CN116917350A - Injection molded article and method for producing same - Google Patents

Abstract

The present invention provides an injection-molded article obtained by injection-molding a copolymer containing Tetrafluoroethylene (TFE) units and fluoro (alkyl vinyl ether) (FAVE) units using a mold having a gate, wherein the content of the fluoro (alkyl vinyl ether) units of the copolymer is 5.2 to 6.3% by mass relative to the total monomer units, the melt flow rate of the copolymer at 372 ℃ is 19.0 to 35.0g/10 min, and the melt flow rate of the copolymer per 10 min ⁶ The number of functional groups having carbon atoms of a main chain is 50 or less, and the injection-molded body has a structure corresponding to the gate of the moldThe ratio ((a)/(b)) of the maximum flow length (a) of the injection molded body from the gate portion to the average value (b) of the product thickness over the maximum flow length is 80 to 200.

Description

Injection molded article and method for producing same

Technical Field

The present invention relates to an injection molded article and a method for producing the same.

Background

Patent document 1 describes an ozone-resistant injection-molded article comprising a perfluoro resin, wherein the perfluoro resin comprises a perfluoropolymer having an MIT value of 30 ten thousand times or more and each 1×10 of the perfluoropolymer ⁶ The number of unstable terminal groups in the number of carbon atoms is 50 or less.

Prior art literature

Patent literature

Patent document 1: international publication No. 2003/048214

Disclosure of Invention

Problems to be solved by the invention

The purpose of the present invention is to provide an injection-molded article which can be produced at high productivity without corroding a mold for molding, has excellent low vapor permeability, high-temperature tensile creep characteristics, low reagent permeability, abrasion resistance at 150 ℃, durability against repeated loads, heat deformation resistance after reagent impregnation, high-temperature high elasticity, and is less likely to cause elution of fluorine ions into a reagent, has high transparency, beautiful appearance, and a large flow length.

Means for solving the problems

According to the present invention, there is provided an injection-molded article obtained by injection-molding a copolymer using a mold having a gate, whereinThe above copolymer contains Tetrafluoroethylene (TFE) units and fluoro (alkyl vinyl ether) (FAVE) units, the content of fluoro (alkyl vinyl ether) units of the above copolymer is 5.2 to 6.3 mass% relative to the total monomer units, the melt flow rate of the above copolymer at 372 ℃ is 19.0 to 35.0g/10 min, and the above copolymer per 10 min ⁶ The number of functional groups having a main chain carbon number is 50 or less, the injection-molded article has a gate portion corresponding to the gate of the mold, and the ratio ((a)/(b)) of the maximum flow length (a) of the injection-molded article from the gate portion to the average value (b) of the product thickness over the maximum flow length is 80 to 200.

In the injection-molded article of the present invention, it is preferable that the fluoro (alkyl vinyl ether) unit of the copolymer is a perfluoro (propyl vinyl ether) unit.

In the injection-molded article of the present invention, the content of the fluoro (alkyl vinyl ether) unit in the copolymer is preferably 5.4 to 6.1% by mass based on the total monomer units.

In the injection-molded article of the present invention, the melt flow rate of the copolymer at 372℃is preferably 20.0g/10 min to 30.9g/10 min.

In the injection-molded article of the present invention, the copolymer preferably has a melting point of 295℃to 305 ℃.

The injection-molded article of the present invention preferably further comprises a welded portion, and the ratio (D/L) of the maximum depth D to the maximum thickness L of the welded portion of the injection-molded article is 0.8 or less.

Further, according to the present invention, there is provided a method for producing the injection molded article, comprising the step of injection molding the copolymer using an injection molding machine and the mold having the gate, wherein an average value d (c/d) of a maximum flow length c of the mold from the gate portion and a cavity thickness of the mold over the maximum flow length is 80 to 200.

In the production method of the present invention, the temperature of the mold is preferably 150 to 250 ℃.

In the production method of the present invention, the cylinder temperature of the injection molding machine is 350 to 420 ℃.

Effects of the invention

According to the present invention, it is possible to provide an injection-molded article which can be produced at high productivity without corroding a mold for molding, has excellent low water vapor permeability, high-temperature tensile creep characteristics, low reagent permeability, abrasion resistance at 150 ℃, durability against repeated loads, heat resistance deformation after reagent impregnation, and high-temperature high elasticity, is less likely to cause elution of fluorine ions into a reagent, has high transparency, has beautiful appearance, and has a large flow length.

Drawings

FIG. 1 is a diagram for explaining a method of producing a micro dumbbell test piece.

Fig. 2 is a diagram showing the shape of a micro dumbbell test piece.

Detailed Description

Hereinafter, specific embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments.

Patent document 1 proposes an ozone resistant injection molded article comprising a perfluoro resin having an MIT value of 30 ten thousand times or more, wherein each 1×10 of the perfluoro resin is a perfluoro polymer, particularly as an article excellent in ozone resistance such as piping material and joint used in a semiconductor manufacturing apparatus ⁶ The number of unstable terminal groups in the number of carbon atoms is 50 or less. In addition, in the example of patent document 1, it is described that: a cap nut having a minimum outer diameter of 43mm, an inner diameter of 27.02mm and a height of 30mm was manufactured by injection molding using an injection molding machine.

However, there is a problem that it is difficult to use the ozone resistance injection molded article described in patent document 1 as an injection molded article having high transparency, beautiful appearance and a large flow length. For example, piping members for transporting a reagent, such as a joint, and flowmeter members for measuring the flow rate of a reagent often have complicated shapes, and transparency and aesthetic appearance capable of confirming the internal state are required for these. In addition, in order to avoid mixing of moisture such as water vapor in the outside air into the reagent, low permeability to water vapor is also required. When the high-pressure reagent or the high-temperature reagent is circulated, the high-pressure reagent or the high-temperature reagent passes through the piping member and the flowmeter member. The pressure of the reagent frequently fluctuates at the start of supply of the fluid, at the stop of supply of the fluid, at the time of change of the supply pressure of the fluid, and the like, and therefore durability against the high-pressure and high-temperature reagent and durability against pressure fluctuation are required. Therefore, there is a demand for a molded article which is excellent in low permeability to water vapor, low permeability to a reagent such as an electrolyte, high-temperature tensile creep characteristics, abrasion resistance at 150 ℃, durability against repeated loads, heat distortion resistance after impregnation with a reagent, high-temperature high elasticity, high transparency, beautiful appearance, and large flow length.

The injection molded body of the present invention is an injection molded body obtained by injection molding a specific copolymer using a mold having a gate, the injection molded body having a gate portion corresponding to the gate of the mold, and the ratio ((a)/(b)) of the maximum flow length (a) of the injection molded body from the gate portion to the average value (b) of the product thickness over the maximum flow length being 80 to 200. Since the injection-molded article of the present invention has such a constitution, it can be produced with high productivity without corroding a mold for molding, and is excellent in low permeability to water vapor, low permeability to a reagent such as an electrolyte, high-temperature tensile creep characteristics, abrasion resistance at 150 ℃, durability against repeated loads, heat-resistant deformability after impregnation with a reagent, high-temperature high elasticity, and high transparency, beautiful appearance, and large flow length, and fluoride ions are not easily eluted into the reagent.

The injection molded body of the present invention has a gate portion. The gate portion is a gate portion corresponding to a gate provided in a mold for injection molding, and can be generally identified as a gate mark remaining on the injection molded body after the gate is separated from the injection molded body on the surface of the injection molded body. The number of gate portions is not particularly limited, but is preferably 1 or more, but may be 4 or less, and more preferably 1.

The injection-molded body of the present invention has a large flow length, and the ratio ((a)/(b)) of the maximum flow length (a) of the injection-molded body from the gate portion to the average value (b) of the product thickness over the maximum flow length is 80 to 200. The ratio ((a)/(b)) is preferably 85 or more, more preferably 87 or more, still more preferably 90 or more, particularly preferably 94 or more, most preferably 100 or more, preferably 150 or less, more preferably 135 or less. Injection molded articles having a large ratio ((a)/(b)) tend to suffer from molding defects such as white fly and surface peeling, and tend to have poor smoothness. Therefore, even when an injection-molded article is composed of a copolymer having a small haze value and excellent transparency, there is a problem that the transparency of the injection-molded article is easily deteriorated. Surprisingly, the injection-molded article of the present invention is excellent in transparency despite a large flow length.

The maximum flow length (a) from the gate portion is a distance at which the copolymer flows in the mold, and can be determined, for example, by measuring a distance at which a weld portion is formed at a portion where the gate portion merges with the copolymer flowing in the mold. Alternatively, in the case where there is no weld between the gate portion and the end of the injection-molded body farthest from the gate portion, it can be determined by measuring the distance between the gate portion and the end of the injection-molded body farthest from the gate portion. In the case where the injection-molded body has a plurality of gate portions, or the like, the distance at which the plurality of copolymers can flow in the mold is determined, the longest distance among the determined distances is taken as the maximum flow length (a) from the gate portions.

The ratio ((a)/(b)) can be obtained by dividing the maximum flow length (a) obtained as described above by the average value (b) of the product thickness over the maximum flow length. The average value (b) of the product thickness over the maximum flow length can be determined as follows: the minimum diameter of the cross section perpendicular to the line drawn for measuring the maximum flow length (a) (the product thickness at the maximum flow length, and the short side when the cross section is a quadrangle) was measured every 2mm along the line drawn for measuring the maximum flow length, and the measured values were accumulated to calculate the average of the measured values.

The injection molded article of the present invention generally has a welded portion corresponding to a portion where the resin flows into and merges in the mold. The weld can be generally confirmed as a weld line on the surface of the injection molded body. In the present invention, the weld includes a weld line which is hardly visible, in addition to a large weld line which is said to be defective in molding.

The injection-molded article of the present invention has a beautiful appearance, and the maximum depth of the welded portion is small. Therefore, in the injection-molded article of the present invention, the ratio (D/L) of the maximum depth (D) to the maximum thickness (L) of the welded portion of the injection-molded article is preferably 0.8 or less, more preferably 0.7 or less, further preferably 0.5 or less, further preferably 0.3 or less, and particularly preferably 0.2 or less. The smaller the maximum depth of the welded portion, the smoother the surface of the injection-molded body, and the more excellent the transparency of the injection-molded body can be said to be. It was also found that the smaller the ratio (D/L) of the maximum depth (D) to the maximum thickness (L) of the fusion-spliced portion of the injection-molded body, the more significantly the tensile strength of the injection-molded body.

The injection molded article of the present invention contains a copolymer containing Tetrafluoroethylene (TFE) units and fluoro (alkyl vinyl ether) (FAVE) units. The copolymer is a melt-processible fluororesin. Melt processability means that a polymer can be melted and processed using existing processing equipment such as an extruder and an injection molding machine.

As the FAVE constituting the above-mentioned FAVE unit, at least one selected from the group consisting of a monomer represented by the general formula (1) and a monomer represented by the general formula (2) is exemplified.

General formula (1):

CF ₂ ＝CFO(CF ₂ CFY ¹ O) _p -(CF ₂ CF ₂ CF ₂ O) _q -Rf (1)

(wherein Y is ¹ Represents F or CF ₃ Rf represents a perfluoroalkyl group having 1 to 5 carbon atoms, p represents an integer of 0 to 5, and q represents an integer of 0 to 5. )

General formula (2):

CFX＝CXOCF ₂ OR ¹ (2)

(wherein X is the same or different and represents H, F or CF ₃ ，R ¹ A fluoroalkyl group having 1 to 6 carbon atoms which may contain 1 to 2 atoms selected from the group consisting of H, cl, br and I and which is linear or branched; or represents a cyclic fluoroalkyl group having 5 or 6 carbon atoms which may contain 1 to 2 atoms of at least 1 selected from the group consisting of H, cl, br and I. )

Among them, as the above FAVE, monomers represented by the general formula (1) are preferable, at least 1 selected from the group consisting of perfluoro (methyl vinyl ether), perfluoro (ethyl vinyl ether) (PEVE) and perfluoro (propyl vinyl ether) (PPVE) are more preferable, at least 1 selected from the group consisting of PEVE and PPVE are more preferable, and PPVE is particularly preferable.

The FAVE unit content of the copolymer is 5.2 to 6.3 mass% relative to the total monomer units. The content of the FAVE unit in the copolymer is preferably 5.3% by mass or more, more preferably 5.4% by mass or more, preferably 6.2% by mass or less, more preferably 6.1% by mass or less, and further preferably 6.0% by mass or less. If the FAVE unit content of the copolymer is too large, the injection-molded article is poor in high-temperature tensile creep characteristics, durability against repeated loads, low water vapor permeability and low reagent permeability, and the injection-molded article is low in elastic modulus at high temperatures. When the content of FAVE units in the copolymer is too small, the heat distortion resistance, abrasion resistance at 150 ℃ and transparency of the injection-molded article after the reagent impregnation are poor.

The TFE unit content of the copolymer is preferably 93.7 to 94.8 mass%, more preferably 93.8 mass% or more, still more preferably 93.9 mass% or more, still more preferably 94.7 mass% or less, still more preferably 94.6 mass% or less, based on the total monomer units. When the content of TFE unit in the copolymer is too small, high-temperature tensile creep characteristics, durability against repeated load, low water vapor permeability and low reagent permeability of the injection molded article may be deteriorated, and the elastic modulus of the injection molded article at high temperature may be lowered. When the content of TFE unit in the copolymer is too large, heat distortion resistance, abrasion resistance at 150 ℃ and transparency of the injection molded article after the reagent impregnation may be deteriorated.

In the present invention, the content of each monomer unit in the copolymer is determined by ¹⁹ F-NMR measurement.

The copolymer may also contain monomer units derived from monomers copolymerizable with TFE and FAVE. In this case, the content of the monomer unit copolymerizable with TFE and FAVE is preferably 0 to 1.1 mass%, more preferably 0.05 to 0.5 mass%, and even more preferably 0.1 to 0.3 mass%, based on the total monomer units of the copolymer.

Examples of monomers copolymerizable with TFE and FAVE include Hexafluoropropylene (HFP) and CZ ¹ Z ² ＝CZ ³ (CF ₂ ) _n Z ⁴ (wherein Z is ¹ 、Z ² And Z ³ Identical or different, H or F, Z ⁴ H, F or Cl, n represents an integer of 2 to 10), and CF ₂ ＝CF-OCH ₂ -Rf ¹ (wherein Rf ¹ A perfluoroalkyl group having 1 to 5 carbon atoms. ) Alkyl perfluorovinyl ether derivatives shown and the like. Among them, HFP is preferable.

The copolymer is preferably at least one selected from the group consisting of a copolymer composed of only TFE units and FAVE units and a TFE/HFP/FAVE copolymer, and more preferably a copolymer composed of only TFE units and FAVE units.

The Melt Flow Rate (MFR) of the copolymer is 19.0 to 35.0g/10 min. The MFR of the copolymer is preferably 19.5g/10 min or more, more preferably 20.0g/10 min or more, still more preferably 22.0g/10 min or more, particularly preferably 23.0g/10 min or more, most preferably 24.0g/10 min or more, preferably 33.9g/10 min or less, more preferably 33.0g/10 min or less, still more preferably 32.9g/10 min or less, particularly preferably 31.9g/10 min or less, most preferably 30.9g/10 min or less. When the MFR of the copolymer is too low, the appearance of the injection-molded article is poor, and not only the low water vapor permeability, transparency, high temperature and high elasticity, durability against repeated loads, and low reagent permeability of the injection-molded article are reduced, but also an injection-molded article having a large flow length may not be obtained. When the MFR of the copolymer is too high, the abrasion resistance at 150 ℃ and the transparency and the heat distortion resistance after the impregnation with the agent are poor.

In the present invention, MFR is a value obtained as a mass (g/10 min) of a polymer flowing out from a nozzle having an inner diameter of 2.1mm and a length of 8mm at 372℃under a 5kg load every 10 minutes using a melt index meter according to ASTM D1238.

The MFR can be adjusted by adjusting the kind and amount of a polymerization initiator used in polymerizing the monomers, the kind and amount of a chain transfer agent, and the like.

In the present invention, every 10 of the copolymer ⁶ The number of functional groups having the number of main chain carbon atoms is 50 or less, preferably 40 or less, more preferably 30 or less, still more preferably 20 or less, still more preferably 15 or less, particularly preferably 10 or less, and most preferably less than 6. By setting the number of functional groups of the copolymer within the above range, the high-temperature tensile creep characteristics and the low permeability of the reagent can be improved, and the amount of fluorine ions eluted from the injection-molded article into the reagent can be greatly reduced. Further, even if the copolymer is molded by filling the mold with the copolymer, the mold is not easily corroded, and therefore the appearance of the injection molded article is not affected by the corrosion of the mold, and the appearance of the obtained injection molded article is more beautiful.

The identification of the kind of the functional group and the measurement of the number of functional groups may be performed by infrared spectroscopic analysis.

Specifically, the number of functional groups was measured by the following method. First, the copolymer was cold-molded to prepare a film having a thickness of 0.25mm to 0.3 mm. The film was analyzed by fourier transform infrared spectroscopy to obtain the infrared absorption spectrum of the above copolymer, and to obtain a differential spectrum from the fully fluorinated background spectrum without functional groups. The specific absorption peak of the specific functional group in the copolymer was calculated for every 1X 10 based on the following formula (A) ⁶ Number of functional groups N of carbon atoms.

N＝I×K/t (A)

I: absorbance of light

K: correction coefficient

t: film thickness (mm)

For reference, the absorption frequency, molar absorptivity, and correction factor are shown in table 1 for some functional groups. The molar absorptivity was determined from FT-IR measurement data of the low molecular weight model compound.

TABLE 1

TABLE 1

-CH ₂ CF ₂ H、-CH ₂ COF、-CH ₂ COOH、-CH ₂ COOCH ₃ 、-CH ₂ CONH ₂ The absorption frequency ratios of (C) are shown in the tables respectively for-CF ₂ H. -COF, free-COOH and bonded-COOH, -COOCH ₃ 、-CONH ₂ Is tens of kesse (cm) ^-1 )。

For example, the functional group number of-COF means the number of functional groups derived from-CF ₂ Absorption frequency of COF 1883cm ^-1 The number of functional groups obtained from the absorption peak at the site and the number of functional groups obtained from the absorption peak derived from-CH ₂ Absorption frequency of COF 1840cm ^-1 The total number of functional groups obtained from the absorption peak at the position.

The functional groups are functional groups present at the main chain end or side chain end of the copolymer and functional groups present in the main chain or side chain. The number of functional groups may be-cf=cf ₂ 、-CF ₂ H、-COF、-COOH、-COOCH ₃ 、-CONH ₂ and-CH ₂ Total number of OH.

The functional group is introduced into the copolymer, for example, by a chain transfer agent or a polymerization initiator used in producing the copolymer. For example, using alcohols as chain transfer agents, or using compounds having-CH ₂ In the case of peroxides of OH structure as polymerization initiators, -CH ₂ OH is introduced into the backbone end of the copolymer. In addition, the functional group is introduced into the terminal of the side chain of the copolymer by polymerizing a monomer having the functional group.

By subjecting the copolymer having such a functional group to fluorination treatment, a copolymer having the number of functional groups in the above range can be obtained. That is, the copolymer contained in the injection-molded article of the present invention is preferably a copolymer after the fluorination treatment. The copolymer contained in the injection-molded article of the present invention preferably also has-CF ₃ End groups.

The melting point of the copolymer is preferably 295 to 315 ℃, more preferably 300 ℃ or higher, still more preferably 301 ℃ or higher, particularly preferably 302 ℃ or higher, still more preferably 310 ℃ or lower, still more preferably 305 ℃ or lower. By having the melting point within the above range, even when the flow length of the injection-molded article is large, the water vapor low permeability, high-temperature tensile creep characteristics, low-permeability of the reagent, abrasion resistance at 150 ℃, durability against repeated loads, heat deformation resistance after reagent impregnation, and high-temperature high-elasticity of the injection-molded article are further improved, and the transparency and appearance are higher.

In the present invention, the melting point can be measured using a differential scanning calorimeter [ DSC ].

The water vapor permeability of the injection-molded article of the present invention is preferably 520g/m ² The following is given. The injection-molded article of the present invention has excellent low permeability to water vapor. Therefore, when the injection-molded article of the present invention is used as a piping member for transporting a reagent, such as a joint, a flowmeter member for measuring the flow rate of a reagent, or the like, it is possible to highly suppress permeation of water vapor in the outside air and mixing of a reagent.

In the present invention, the water vapor permeability can be measured at a temperature of 95℃for 60 days. Specific measurement of the water vapor permeability can be performed by the method described in examples.

The haze value of the injection-molded article of the present invention is preferably 7.0% or less, more preferably 6.7% or less. When the haze value of the injection-molded article is in the above range, for example, in the case where the injection-molded article of the present invention is used as a molded article such as a valve, a filter cover, a pipe, a joint, a bottle, a flowmeter, or the like, it is easy to observe the inside of the molded article by visual observation, a camera, or the like, and it is easy to confirm the flow rate and the remaining amount of the content. In the present invention, the haze value can be measured in accordance with JIS K7136.

The storage modulus (E') of the injection-molded article of the present invention at 150℃is preferably 75MPa or more, more preferably 80MPa or more, preferably 1000MPa or less, more preferably 500MPa or less, and still more preferably 300MPa or less. By making the storage modulus (E') of the injection-molded body at 150 ℃ within the above range, the elastic modulus of the injection-molded body at high temperature becomes higher, and the high-temperature high-elasticity becomes more excellent. Therefore, the durability of the injection-molded body when contacted with a high-pressure and high-temperature reagent is further improved.

The storage modulus (E') can be measured by dynamic viscoelasticity measurement at a temperature rising rate of 2 ℃/min and a frequency of 10Hz at a temperature ranging from 30 ℃ to 250 ℃.

In the injection-molded article of the present invention, the amount of the eluted fluoride ion detected in the electrolyte impregnation test is preferably 1.0ppm or less, more preferably 0.8ppm or less, and still more preferably 0.7ppm or less on a mass basis. When the injection-molded article of the present invention is used as a piping member for transporting a reagent, such as a joint, a flowmeter member for measuring the flow rate of a reagent, or the like, contamination of a reagent with fluoride ions can be highly suppressed.

In the present invention, the electrolyte impregnation test can be performed as follows: test pieces having a weight corresponding to 4 pieces of injection-molded articles (15 mm. Times.15 mm. Times.0.5 mmt) were produced, and a glass sample bottle containing the test pieces and 2g of dimethyl carbonate (DMC) was placed in a constant temperature bath at 80℃and left for 144 hours.

The injection-molded article of the present invention may contain other components such as fillers, plasticizers, processing aids, mold release agents, pigments, flame retardants, lubricants, light stabilizers, weather stabilizers, conductive agents, antistatic agents, ultraviolet absorbers, antioxidants, foaming agents, fragrances, oils, softeners, dehydrofluorination agents, and the like.

Examples of the filler include silica, kaolin, clay, organized clay, talc, mica, alumina, calcium carbonate, calcium terephthalate, titanium oxide, calcium phosphate, calcium fluoride, lithium fluoride, crosslinked polystyrene, potassium titanate, carbon, boron nitride, carbon nanotubes, and glass fibers. Examples of the conductive agent include carbon black. Examples of the plasticizer include dioctyl phthalate and pentaerythritol. Examples of the processing aid include carnauba wax, sulfone compound, low molecular weight polyethylene, and fluorine-based aid. Examples of the dehydrofluorination agent include organic onium and amidines.

As the other components, other polymers than the above copolymers may be used. Examples of the other polymer include a fluororesin other than the above copolymer, a fluororubber, a nonfluorinated polymer, and the like.

The copolymer contained in the injection-molded article of the present invention can be produced by a polymerization method such as suspension polymerization, solution polymerization, emulsion polymerization, or bulk polymerization. As the polymerization method, emulsion polymerization or suspension polymerization is preferable. In these polymerizations, the conditions such as temperature and pressure, polymerization initiator, and other additives may be appropriately set according to the composition and amount of the copolymer.

As the polymerization initiator, an oil-soluble radical polymerization initiator or a water-soluble radical polymerization initiator can be used.

The oil-soluble radical polymerization initiator may be a known oil-soluble peroxide, and the following are exemplified as typical examples:

dialkyl peroxycarbonates such as di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, and di-2-ethoxyethyl peroxydicarbonate;

peroxyesters such as t-butyl peroxyisobutyrate and t-butyl peroxypivalate;

dialkyl peroxides such as di-t-butyl peroxide;

di [ fluoro (or fluoro chloro) acyl ] peroxides; etc.

As bis [ fluoro (or fluoro chloro) acyl groups]The peroxides include [ (RfCOO) & lt- & gt ]] ₂ (Rf is perfluoroalkyl, omega-hydroperfluoroalkyl or fluorochloroalkyl).

Examples of the di [ fluoro (or fluorochloroacyl ] peroxides include di (ω -hydro-dodecafluoroheptanoyl) peroxide, di (ω -hydro-hexadecanoyl) peroxide, di (perfluoropropionyl) peroxide, di (perfluorobutanoyl) peroxide, di (perfluoropentanoyl) peroxide, di (perfluorohexanoyl) peroxide, di (perfluoroheptanoyl) peroxide, di (perfluorooctanoyl) peroxide, di (perfluorononanoyl) peroxide, di (ω -chloro-hexafluorobutanoyl) peroxide, di (ω -chloro-dodecafluoroheptanoyl) peroxide, di (ω -chloro-dodecafluorooctanoyl) peroxide, ω -hydro-dodecafluoroheptanoyl-peroxide, ω -chloro-hexafluorobutanoyl-peroxide, ω -hydrododecafluoroheptanoyl-perfluorobutanoyl-peroxide, di (perfluoroheptanoyl) peroxide, di (dichloro-heptanoyl) peroxide, di (dichloro-dodecanoyl) peroxide, and di (dichloro-dodecanoyl) dodecanoyl peroxide.

The water-soluble radical polymerization initiator may be a known water-soluble peroxide, and examples thereof include ammonium salts such as persulfuric acid, perboric acid, perchloric acid, perphosphoric acid, and percarbonic acid, potassium salts, sodium salts, disuccinic acid peroxide, and organic peroxides such as dipentaerythritol peroxide, t-butyl peroxymaleate, and t-butyl hydroperoxide. The reducing agent such as sulfite may be used in combination with the peroxide in an amount of 0.1 to 20 times the amount of the peroxide.

In the polymerization, a surfactant, a chain transfer agent and a solvent may be used, and conventionally known ones may be used, respectively.

As the surfactant, a known surfactant can be used, and for example, a nonionic surfactant, an anionic surfactant, a cationic surfactant, and the like can be used. Among them, the fluorinated anionic surfactant is preferable, and the fluorinated anionic surfactant having 4 to 20 carbon atoms, which may be linear or branched, and which may or may not contain ether-bonded oxygen (i.e., may have an oxygen atom interposed between carbon atoms), is more preferable. The amount of the surfactant to be added (relative to the polymerization water) is preferably 50ppm to 5000ppm.

Examples of the chain transfer agent include: hydrocarbons such as ethane, isopentane, n-hexane, and cyclohexane; aromatic compounds such as toluene and xylene; ketones such as acetone; acetate esters such as ethyl acetate and butyl acetate; alcohols such as methanol and ethanol; mercaptans such as methyl mercaptan; halogenated hydrocarbons such as carbon tetrachloride, chloroform, methylene chloride and methyl chloride; etc. The amount of the chain transfer agent to be added may vary depending on the amount of the chain transfer constant of the compound to be used, and is usually in the range of 0.01 to 20% by mass relative to the polymerization solvent.

Examples of the solvent include water, a mixed solvent of water and alcohol, and the like.

In the suspension polymerization, a fluorine-based solvent may be used in addition to water. As the fluorine-based solvent, CH may be mentioned ₃ CClF ₂ 、CH ₃ CCl ₂ F、CF ₃ CF ₂ CCl ₂ H、CF ₂ ClCF ₂ Hydrochlorofluoroalkanes such as CFHCl; CF (compact flash) ₂ ClCFClCF ₂ CF ₃ 、CF ₃ CFClCFClCF ₃ Isophlorofluoroalkanes; CF (compact flash) ₃ CFHCFHCF ₂ CF ₂ CF ₃ 、CF ₂ HCF ₂ CF ₂ CF ₂ CF ₂ H、CF ₃ CF ₂ CF ₂ CF ₂ CF ₂ CF ₂ CF ₂ Hydrofluoroalkanes such as H; CH (CH) ₃ OC ₂ F ₅ 、CH ₃ OC ₃ F ₅ CF ₃ CF ₂ CH ₂ OCHF ₂ 、CF ₃ CHFCF ₂ OCH ₃ 、CHF ₂ CF ₂ OCH ₂ F、(CF ₃ ) ₂ CHCF ₂ OCH ₃ 、CF ₃ CF ₂ CH ₂ OCH ₂ CHF ₂ 、CF ₃ CHFCF ₂ OCH ₂ CF ₃ Isohydrofluoroethers; perfluorocyclobutane, CF ₃ CF ₂ CF ₂ CF ₃ 、CF ₃ CF ₂ CF ₂ CF ₂ CF ₃ 、CF ₃ CF ₂ CF ₂ CF ₂ CF ₂ CF ₃ Among them, perfluoroalkanes are preferable. The amount of the fluorine-based solvent to be used is preferably 10 to 100% by mass based on the aqueous medium in view of suspension property and economy.

The polymerization temperature is not particularly limited, and may be 0 to 100 ℃. The polymerization pressure is appropriately determined depending on the kind and amount of the solvent used, the vapor pressure, the polymerization temperature, and other polymerization conditions, and may be generally 0 to 9.8MPaG.

When an aqueous dispersion containing a copolymer is obtained by polymerization, the copolymer contained in the aqueous dispersion can be precipitated, washed, and dried to recover the copolymer. In addition, in the case where the copolymer is obtained as a slurry by polymerization, the copolymer can be recovered by taking out the slurry from the reaction vessel, washing it, and drying it. The copolymer can be recovered in the form of a powder by drying.

The copolymer obtained by polymerization may be molded into pellets. The molding method for molding the pellets is not particularly limited, and conventionally known methods can be used. For example, a method of melt-extruding a copolymer using a single screw extruder, a twin screw extruder, or a tandem extruder, cutting the copolymer into a predetermined length, and molding the copolymer into pellets, and the like can be mentioned. The extrusion temperature at the time of melt extrusion is required to be changed depending on the melt viscosity of the copolymer and the production method, and is preferably from +20℃to +140℃of the melting point of the copolymer. The method of cutting the copolymer is not particularly limited, and conventionally known methods such as a wire cutting method, a thermal cutting method, an underwater cutting method, and a sheet cutting method can be employed. The volatile components in the pellets may also be removed by heating the resulting pellets (degassing treatment). The obtained pellets may be treated by contacting them with warm water at 30 to 200 ℃, steam at 100 to 200 ℃ or hot air at 40 to 200 ℃.

The copolymer obtained by polymerization may also be subjected to a fluorination treatment. The fluorination treatment may be performed by contacting the copolymer that has not been subjected to the fluorination treatment with a fluorine-containing compound. By fluorination treatment, the-COOH, -COOCH-of the copolymer can be obtained ₃ 、-CH ₂ OH、-COF、-CF＝CF ₂ 、-CONH ₂ Isothermally labile functional groups and relatively thermally stable-CF ₂ Conversion of functional groups such as H to extremely thermally stable-CF ₃ . As a result, the-COOH, -COOCH-of the copolymer can be used ₃ 、-CH ₂ OH、-COF、-CF＝CF ₂ 、-CONH ₂ and-CF ₂ The total number of H (the number of functional groups) is easily adjusted to be within the above-mentioned range.

The fluorine-containing compound is not particularly limited, and examples thereof include a fluorine radical source that generates a fluorine radical under the fluorination treatment conditions. As the fluorine radical sourceExamples thereof include F ₂ Gas, coF ₃ 、AgF ₂ 、UF ₆ 、OF ₂ 、N ₂ F ₂ 、CF ₃ OF, fluorinated halogens (e.g. IF ₅ 、ClF ₃ ) Etc.

F ₂ The fluorine radical source such as gas may be used at a concentration of 100%, but from the viewpoint of safety, it is preferably used by mixing with an inactive gas and diluting to 5 to 50% by mass, more preferably 15 to 30% by mass. The inert gas may be nitrogen, helium, argon, or the like, and nitrogen is preferable from the viewpoint of economy.

The conditions of the fluorination treatment are not particularly limited, and the copolymer in a molten state may be brought into contact with the fluorine-containing compound, but may be usually conducted at a temperature of 20 to 240℃and more preferably 100 to 220℃below the melting point of the copolymer. The fluorination treatment is generally carried out for 1 to 30 hours, preferably 5 to 25 hours. The fluorination treatment preferably involves reacting the copolymer which has not been subjected to the fluorination treatment with fluorine gas (F ₂ Gas) contact.

The injection-molded article of the present invention can be produced by a production method in which the copolymer obtained as described above is injection-molded using an injection molding machine and a mold having a gate. According to the production method of the present invention, an injection-molded article can be produced at high productivity without corroding a mold for molding, and an injection-molded article having low water vapor permeability, high-temperature tensile creep characteristics, low reagent permeability, abrasion resistance at 150 ℃, durability against repeated loads, excellent heat deformation resistance after reagent impregnation, high-temperature high elasticity, less tendency to dissolve out fluorine ions into a reagent, high transparency, beautiful appearance, and a large flow length can be produced. Further, since the production method of the present invention is a method of molding the copolymer, injection molded articles having a large flow length and a complicated shape, for example, injection molded articles such as flowmeter cases, valve cases, and filter covers can be easily produced by using the production method of the present invention.

The shape of the copolymer to be supplied to the injection molding machine is not particularly limited, and a copolymer in the form of powder, pellet, or the like may be used.

As the injection molding machine, a known injection molding machine can be used. The copolymer injected from the nozzle of the injection molding machine typically flows through the sprue and runner, through the sprue and into the mold cavity, filling the mold cavity. A runner and a gate are formed in a mold for injection molding, and a mold cavity for forming an injection molded body is formed.

The shape of the inlet is not particularly limited, and may be circular, rectangular, trapezoidal, or the like. The shape of the flow channel is not particularly limited, and may be circular, rectangular, trapezoidal, or the like. The runner system is not particularly limited, and may be a cold runner or a hot runner. The gate method is not particularly limited, and may be a direct gate, a side gate, a submerged gate, or the like. The number of gates relative to the mold cavity is not particularly limited. Either a mold having a single point gate structure or a mold having a multi point gate structure may be used. The number of die cavities (the number of cavities) of the die is preferably 1 to 64.

In injection molding, a mold having a ratio ((c)/(d)) of a maximum flow length (c) of the mold from the gate portion to an average value (d) of the thickness of the cavity of the mold over the maximum flow length of 80 to 200 is used as a flow length of the copolymer from the gate. The ratio ((c)/(d)) is preferably 85 or more, more preferably 87 or more, further preferably 90 or more, particularly preferably 94 or more, most preferably 100 or more, preferably 150 or less, further preferably 135 or less.

The more the portions having a small thickness in the cavity of the mold for injection molding, that is, the larger the ratio ((c)/(d)), the more difficult the copolymer flow length is to be elongated, the more difficult is to obtain a large injection molded article having a large number of thin wall portions (that is, the injection molded article having a large ratio ((a)/(b)), and the obtained injection molded article tends to be poor in appearance and transparency. On the other hand, in the case of the conventional injection-molded article having a large ratio ((a)/(b)), there is room for improvement in water vapor low permeability, high-temperature tensile creep characteristics, low permeability of the reagent, abrasion resistance at 150 ℃, durability against repeated loads, heat resistance deformation after impregnation of the reagent, and high-temperature high elasticity even when the appearance is excellent. Further, injection-molded articles that are difficult to dissolve out fluoride ions into the reagent are also desired. The production method of the present invention has the above-described constitution, and therefore enables the production of an injection-molded article having a ratio ((a)/(b)) falling within the above-described range, and being excellent in low vapor permeability, high-temperature tensile creep characteristics, low reagent permeability, abrasion resistance at 150 ℃, durability against repeated loads, heat resistance deformation after reagent impregnation, and high-temperature high-elasticity, being less likely to cause elution of fluorine ions into a reagent, high transparency, and beautiful appearance.

In the production method of the present invention, the temperature of the mold is preferably 150 to 250 ℃, more preferably 170 ℃ or higher, even more preferably 230 ℃ or lower, even more preferably 200 ℃ or lower, from the viewpoint that corrosion of the mold can be further suppressed, the water vapor low permeability, the high temperature tensile creep property, the reagent low permeability, the abrasion resistance at 150 ℃, the durability against repeated loads, the heat deformation resistance after the reagent impregnation, and the high temperature high elasticity are more excellent, the transparency is higher, and the appearance is more beautiful.

In the production method of the present invention, the temperature of the cylinder provided in the injection molding machine is preferably 350 to 420 ℃, more preferably 370 ℃ or higher, and even more preferably 400 ℃ or lower, from the viewpoint that the injection molded article can be produced with low water vapor permeability, high-temperature tensile creep characteristics, low reagent permeability, abrasion resistance at 150 ℃, durability against repeated loads, heat deformation resistance after reagent impregnation, and high-temperature high-elasticity, and higher transparency, and more beautiful appearance.

The injection-molded article of the present invention can be used for various purposes. The injection molded article of the present invention may be, for example, nuts, bolts, fittings, films, bottles, gaskets, tubes, hoses, pipes, valves, sheets, seals, gaskets, tanks, rollers, containers, taps, connectors, filter housings, filter covers, flow meters, pumps, wafer carriers, wafer cassettes, and the like.

The injection molded article of the present invention can be produced at high productivity without corroding a mold used for molding, has excellent low vapor permeability, high-temperature tensile creep characteristics, low reagent permeability, abrasion resistance at 150 ℃, durability against repeated loads, heat resistance deformation after reagent impregnation, and high-temperature high elasticity, is less likely to cause elution of fluorine ions into a reagent, has high transparency, has beautiful appearance, and has a large flow length, and therefore can be suitably used for nuts, bolts, joints, gaskets, valves, taps, connectors, filter housings, filter covers, flowmeters, pumps, and the like. For example, the present invention can be suitably used as a piping member (in particular, a valve case or a filter cover) for transferring a reagent or a flowmeter case having a flow path for a reagent in a flowmeter. The piping member and the flowmeter case of the present invention are excellent in low vapor permeability, high-temperature tensile creep characteristics, low reagent permeability, abrasion resistance at 150 ℃, durability against repeated loads, heat distortion resistance after reagent impregnation, high-temperature high elasticity, high transparency, and beautiful appearance. Therefore, the piping member and the flowmeter case of the present invention are excellent in visibility, and particularly in the flowmeter case, the float inside can be easily observed by visual observation, a camera, or the like, and the piping member and the flowmeter case can be suitably used for measuring the flow rate of a reagent at about 150 ℃, and are less likely to be damaged even if stress is repeatedly applied by the start of the flow of the reagent, the stop of the flow, or the change of the flow rate. Further, the piping member and the flowmeter case of the present invention can be manufactured at an extremely high injection speed without corroding a mold for molding, even in the case of having a thin wall portion, and are excellent in appearance.

The injection molded article of the present invention can be produced at high productivity without corroding a mold used for molding, has excellent low vapor permeability, high-temperature tensile creep characteristics, low reagent permeability, abrasion resistance at 150 ℃, durability against repeated loads, heat resistance deformation after reagent impregnation, and high-temperature high elasticity, is less likely to cause elution of fluorine ions into a reagent, has high transparency, has beautiful appearance, and has a large flow length, and therefore can be suitably used as a compressed member such as a gasket or a gasket.

The injection molded article of the present invention can be produced with high productivity without corroding a mold used for molding, has excellent water vapor low permeability, high-temperature tensile creep characteristics, low reagent permeability, abrasion resistance at 150 ℃, durability against repeated loads, heat deformation resistance after reagent impregnation, and high-temperature high elasticity, is less likely to cause elution of fluorine ions into a reagent, has high transparency, beautiful appearance, and has a large flow length, and therefore can be suitably used as a bottle or a tube. The bottle or tube of the present invention can easily visually confirm the content, and is not easily damaged in use.

The injection molded article of the present invention can be produced at high productivity without corroding a mold used for molding, and is excellent in low water vapor permeability, high-temperature tensile creep characteristics, low reagent permeability, abrasion resistance at 150 ℃, durability against repeated loads, heat resistance deformation after reagent impregnation, high-temperature high elasticity, resistance to elution of fluorine ions into a reagent, high transparency, beautiful appearance, and large flow length. Thus, the injection molding of the present invention can be suitably used for a valve housing or a valve. The valve of the present invention can be manufactured at low cost and with extremely high productivity without corroding a mold, and is not easily damaged even if repeatedly opened and closed at a high frequency, and is excellent in low water vapor permeability, high-temperature tensile creep characteristics, low reagent permeability, abrasion resistance at 150 ℃, durability against repeated loads, heat deformation resistance after reagent impregnation, and high-temperature high elasticity. The valve of the present invention has a high elastic modulus even at high temperatures, and thus can be suitably used for controlling a fluid at 100 ℃ or higher, particularly at about 150 ℃.

While the embodiments have been described above, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the claims.

Examples

Next, embodiments of the present invention will be described with reference to examples, but the present invention is not limited to the examples.

The values of the examples were measured by the following methods.

(content of monomer units)

The content of each monomer unit was measured by an NMR analyzer (for example, AVANCE300 high temperature probe manufactured by Bruker Biospin Co.).

(melt flow Rate (MFR))

The mass (G/10 minutes) of the polymer flowing out from a nozzle having an inner diameter of 2.1mm and a length of 8mm per 10 minutes was determined by using a melt index analyzer G-01 (manufactured by Toyo Seisakusho-Sho Co., ltd.) at 372℃under a 5kg load in accordance with ASTM D1238.

(melting point)

The melting point was determined from the melting curve peak generated during the 2 nd heating process by performing the 1 st heating from 200℃to 350℃at a heating rate of 10℃per minute using a differential scanning calorimeter (trade name: X-DSC7000, manufactured by Hitachi High-Tech Science Co., ltd.), then cooling from 350℃to 200℃at a cooling rate of 10℃per minute, and performing the 2 nd heating from 200℃to 350℃again at a heating rate of 10℃per minute.

(number of functional groups)

The pellets of the copolymer were cold-molded to prepare a film having a thickness of 0.25mm to 0.3 mm. By Fourier transform infrared Spectrum analysis device [ FT-IR (Spectrum One manufactured by Perkinelmer Co.)]The film was scanned 40 times and analyzed to obtain an infrared absorption spectrum and a differential spectrum from a fully fluorinated background spectrum without functional groups. The absorbance peak of the specific functional group shown by the differential spectrum was calculated for every 1X 10 in the sample according to the following formula (A) ⁶ Number of functional groups N of carbon atoms.

N＝I×K/t (A)

I: absorbance of light

K: correction coefficient

t: film thickness (mm)

For reference, regarding the functional groups in the present invention, the absorption frequency, molar absorptivity, and correction coefficient are shown in table 2. The molar absorptivity is determined from FT-IR measurement data of the low molecular weight model compound.

TABLE 2

TABLE 2

Synthesis example 1

After adding 49L of pure water to a 174L-volume autoclave and sufficiently performing nitrogen substitution, 40.7kg of perfluorocyclobutane, 1.90kg of perfluoro (propyl vinyl ether) (PPVE) and 3.20kg of methanol were added, the temperature in the system was kept at 35℃and the stirring speed was kept at 200rpm. Subsequently, tetrafluoroethylene (TFE) was introduced under pressure to 0.64MPa, and then 0.041kg of a 50% methanol solution of di-n-propyl peroxydicarbonate was introduced to start polymerization. Since the pressure in the system decreased as polymerization proceeded, TFE was continuously fed so that the pressure became constant, and 0.057kg of PPVE was added per 1kg of TFE fed, and polymerization was continued for 19 hours. TFE was discharged, and after the autoclave was allowed to return to atmospheric pressure, the obtained reaction product was washed with water and dried to obtain 30kg of powder.

The obtained powder was melt-extruded at 360℃by a screw extruder (trade name: PCM46, manufactured by Mitsui Co., ltd.) to obtain pellets of TFE/PPVE copolymer. Using the pellets obtained, the PPVE content was determined by the method described above. The results are shown in Table 3.

The obtained pellets were placed in a vacuum vibration type reaction apparatus VVD-30 (manufactured by Dachuan origin Co., ltd.) and heated to 210 ℃. After evacuation, N for introduction ₂ F gas dilution to 20 vol% ₂ The gas is brought to atmospheric pressure. From F ₂ After 0.5 hour from the time of gas introduction, the mixture was once evacuated and F was introduced again ₂ And (3) gas. After 0.5 hour, the mixture was again evacuated and F was introduced again ₂ And (3) gas. Thereafter, F is as described above ₂ The gas introduction and evacuation operations were continued for 1 time within 1 hour, and the reaction was carried out at 210℃for 10 hours. After the reaction, the inside of the reactor was fully replaced with N ₂ And (3) ending the fluorination reaction by using the gas. Using the fluorinated pellets, various physical properties were measured by the above-described method. The results are shown in Table 3.

Synthesis example 2

Fluorinated pellets were obtained in the same manner as in example 1 except that PPVE was changed to 2.01kg, methanol was changed to 3.15kg, and PPVE was changed to 0.059kg added per 1kg of TFE supplied. The results are shown in Table 3.

Synthesis example 3

Fluorinated pellets were obtained in the same manner as in example 1, except that PPVE was changed to 2.10kg, methanol was changed to 4.10kg, PPVE was changed to 0.062kg per 1kg of TFE supplied, and the polymerization time was changed to 20 hours. The results are shown in Table 3.

Synthesis example 4

Fluorinated pellets were obtained in the same manner as in example 1, except that PPVE was changed to 2.24kg, methanol was changed to 3.70kg, PPVE was changed to 0.064kg added per 1kg of TFE supplied, and the polymerization time was changed to 19.5 hours. The results are shown in Table 3.

Synthesis example 5

Fluorinated pellets were obtained in the same manner as in Synthesis example 1 except that PPVE was changed to 2.29kg, methanol was changed to 3.30kg, PPVE was added to 0.065kg per 1kg of TFE supplied, the temperature of the vacuum vibration type reactor was changed to 170℃and the reaction time was changed to 5 hours at 170 ℃. The results are shown in Table 3.

Synthesis example 6

Fluorinated pellets were obtained in the same manner as in Synthesis example 1 except that 2.53kg of methanol was used and the polymerization time was changed to 18.5 hours. The results are shown in Table 3.

Synthesis example 7

Fluorinated pellets were obtained in the same manner as in Synthesis example 1 except that 34.0L of pure water, 30.4kg of perfluorocyclobutane, 1.14kg of PPVE, 3.10kg of methanol, 0.60MPa of TFE pressure, 0.060kg of 50% methanol solution of di-n-propyl peroxydicarbonate, 0.058kg of PPVE was added to 1kg of TFE, and the polymerization time was changed to 24.5 hours. The results are shown in Table 3.

Synthesis example 8

Fluorinated pellets were obtained in the same manner as in Synthesis example 1 except that the amount of pure water was changed to 34.0L, perfluorocyclobutane was changed to 30.4kg, PPVE was changed to 0.98kg, methanol was changed to 1.30kg, TFE was pressed to 0.60MPa, 50% methanol solution of di-n-propyl peroxydicarbonate was changed to 0.060kg, PPVE was changed to 0.052kg added per 1kg of TFE supplied, and the polymerization time was changed to 23 hours. The results are shown in Table 3.

Synthesis example 9

Fluorinated pellets were obtained in the same manner as in Synthesis example 1 except that PPVE was changed to 2.24kg, methanol was changed to 4.02kg, PPVE was changed to 0.064kg added per 1kg of TFE supplied, and the polymerization time was changed to 20 hours. The results are shown in Table 3.

Synthesis example 10

After filling a 174L-volume autoclave with 51.8L of pure water and sufficiently replacing the pure water with nitrogen, 40.9kg of perfluorocyclobutane, 3.01kg of perfluoro (propyl vinyl ether) (PPVE) and 1.78kg of methanol were charged, the temperature in the system was kept at 35℃and the stirring speed was kept at 200rpm. Subsequently, tetrafluoroethylene (TFE) was introduced under pressure to 0.64MPa, and then 0.051kg of a 50% methanol solution of di-n-propyl peroxydicarbonate was introduced to start polymerization. Since the pressure in the system decreased as polymerization proceeded, TFE was continuously fed so that the pressure became constant, and 0.063kg of PPVE was additionally fed per 1kg of TFE fed. When the additional amount of TFE fed reached 40.9kg, polymerization was terminated. Unreacted TFE was discharged, the pressure in the autoclave was returned to the atmospheric pressure, and the obtained reaction product was washed with water and dried to obtain 43.5kg of a powder.

The obtained powder was melt-extruded at 360℃by a screw extruder (trade name: PCM46, manufactured by Mitsui Co., ltd.) to obtain pellets of TFE/PPVE copolymer. Using the pellets obtained, the PPVE content was determined by the method described above.

The obtained pellets were placed in a vacuum vibration type reaction apparatus VVD-30 (manufactured by Dachuan origin Co., ltd.) and heated to 210 ℃. After evacuation, N for introduction ₂ F gas dilution to 20 vol% ₂ The gas is brought to atmospheric pressure. From F ₂ After 0.5 hour from the time of gas introduction, the mixture was once evacuated and F was introduced again ₂ And (3) gas. After 0.5 hour, the mixture was again evacuated and F was introduced again ₂ And (3) gas. Thereafter, F is as described above ₂ The gas introduction and evacuation operations were continued for 1 time within 1 hour, and the reaction was carried out at 210℃for 10 hours. After the reaction, the inside of the reactor was fully replaced with N ₂ And (3) ending the fluorination reaction by using the gas. The results are shown in Table 3.

Synthesis example 11

Fluorinated pellets were obtained in the same manner as in Synthesis example 1 except that PPVE was changed to 2.81kg, methanol was changed to 2.83kg, PPVE was changed to 0.075kg per 1kg of TFE supplied, and the polymerization time was changed to 19.5 hours. The results are shown in Table 3.

TABLE 3

TABLE 3 Table 3

The expression "< 6" in Table 3 means that the number of functional groups is less than 6.

Experimental examples 1 to 6 and comparative experimental examples 1 to 5

Using the pellets obtained above, sheet-like injection molded articles having different shapes were produced by the following method. The obtained sheet-like injection-molded article was evaluated. The results are shown in Table 4.

Sheet injection molded body (40 mm. Times.40 mm. Times.0.5 mmt)

The copolymer was injection molded using an injection molding machine (SE 50 EV-Sup>A, manufactured by sumitomo heavy machinery industries, inc.) with the cartridge temperature set at 400 ℃, the mold temperature set at 200 ℃ and the injection speed set at 20 mm/s. As a mold, a mold made of HPM38 (40 mm. Times.40 mm. Times.0.5 mmT,4 cavities, side gates) was used.

Sheet injection molded body (45 mm. Times.45 mm. Times.0.6 mmt)

The copolymer was injection molded using an injection molding machine (SE 50 EV-Sup>A, manufactured by sumitomo heavy machinery industries, inc.) with the cartridge temperature set at 400 ℃, the mold temperature set at 230 ℃ and the injection speed set at 20 mm/s. As a mold, a mold made of HPM38 (45 mm. Times.45 mm. Times.0.6 mmt,4 cavities, side gates) was used.

Sheet injection molded body (155 mm. Times.100 mm. Times.2 mmt)

The copolymer was injection molded using an injection molding machine (SE 50 EV-Sup>A, manufactured by sumitomo heavy machinery industries, inc.) with the cartridge temperature set at 380 ℃, the mold temperature set at 180 ℃ and the injection speed set at 10 mm/s. As the mold, a mold (155 mm×100mm×2mmt, film gate) in which Cr plating was performed on HPM38 was used.

Sheet injection molded body (180 mm. Times.60 mm. Times.2.4 mmt)

The copolymer was injection molded using an injection molding machine (SE 50 EV-Sup>A, manufactured by sumitomo heavy machinery industries, inc.) with the cartridge temperature set at 380 ℃, the mold temperature set at 180 ℃ and the injection speed set at 10 mm/s. As the mold, a mold (180 mm×60mm×2.4mmt, film gate) in which Cr plating was performed on HPM38 was used.

(vapor permeability)

A sheet-like test piece was produced from the injection-molded article (40 mm. Times.40 mm. Times.0.5 mmt) after the sheet-like injection-molded article was left at 60℃for 24 hours. A sheet-like test piece having a thickness of about 0.2mm was produced using the pellets and a hot press molding machine. In the test cup (penetration area 7.065 cm) ² ) 10g of water was put therein, covered with a sheet-like injection molded body, and fastened and sealed with a PTFE gasket interposed therebetween. The sheet-like test piece was brought into contact with water, kept at a temperature of 95℃for 60 days, taken out, left at room temperature for 2 hours, and then the mass reduction was measured. By measuring the water vapor permeability (g/m ² )。

Water vapor transmission rate (g/m) ² ) =mass reduction (g)/transmission area (m ² )

(haze value)

After the sheet-like injection-molded article (45 mm. Times.45 mm. Times.0.6 mmt) was left at 60℃for 24 hours, the sheet was immersed in a quartz cell containing pure water in accordance with JIS K7136 using a haze meter (trade name: NDH 7000SP, manufactured by Nippon Denshoku Co., ltd.), and the haze value was measured.

(storage modulus (E')

The dynamic viscoelasticity was measured by using DVA-220 (manufactured by IT meter control Co.). After the sheet-like injection-molded article (40 mm. Times.40 mm. Times.0.5 mmt) was left at 60℃for 24 hours, test pieces 25mm in length and 5mm in width were cut, and the storage modulus (MPa) at 150℃was read by measuring the temperature in the range of 30℃to 250℃at a heating rate of 2℃per minute and a frequency of 10 Hz.

(tensile creep test)

The tensile creep strain was measured using TMA-7100 manufactured by Hitachi high technology Co. A sheet-like injection molded article (40 mm. Times.40 mm. Times.0.5 mmt) was punched out to prepare a sample having a width of 2mm and a length of 22 mm. The sample was mounted to the measuring jig at a distance of 10mm from the jig. For the sample, the cross-sectional load was 2.41N/mm ² The sample was subjected to a load of 240℃and a displacement (mm) of the length of the sample was measured from the time point of 70 minutes after the start of the test to the time point of 300 minutes after the start of the test, and the ratio (tensile creep strain (%)) of the displacement (mm) of the length to the initial sample length (10 mm) was calculated. The sheet having a small tensile creep strain (%) measured at 240℃for 300 minutes is less likely to be elongated even under a very high temperature environment under a tensile load, and is excellent in high temperature tensile creep characteristics.

(electrolyte impregnation test)

A15 mm square test piece was cut out from the sheet-like injection molded article (40 mm. Times.40 mm. Times.0.5 mmt). To a 20mL glass sample bottle, 4 pieces of the test piece and 2g of dimethyl carbonate (DMC) were added, and the cap of the sample bottle was closed. The sample bottle was placed in a constant temperature bath at 80℃and left for 240 hours, whereby the test piece was immersed in DMC. Then, the sample bottle was taken out of the incubator, cooled to room temperature, and then the test piece was taken out of the sample bottle. DMC remaining after the test piece was taken out was air-dried in a room at 25℃for 24 hours in a state of being placed in a sample bottle, and 2g of ultrapure water was added. The resulting aqueous solution was transferred to a cell of an ion chromatography system, and the fluorine ion content of the aqueous solution was measured by the ion chromatography system (Dionex ICS-2100, manufactured by Thermo Fisher Scientific Co.).

(test for cracks in reagent impregnation (thermal deformation resistance after reagent impregnation))

3 test pieces were obtained by punching out a sheet-like injection-molded article (155 mm. Times.100 mm. Times.2 mmt) using a 13.5 mm. Times.38 mm rectangular dumbbell. A notch was cut in the center of the long side of each test piece obtained by using a blade of 19mm X0.45 mm in accordance with ASTM D1693. In a 100mL container, 3 notched test pieces and 25g of 85% phosphoric acid aqueous solution were placed, and after heating at 120℃for 100 hours in an electric furnace, the notched test pieces were taken out. The 3 obtained notched test pieces were mounted on a stress crack test jig according to ASTM D1693, and after heating at 150 ℃ for 24 hours in an electric furnace, the notches and the periphery thereof were visually observed to count the number of cracks. The sheet having no cracks was excellent in heat distortion resistance even after being immersed in a reagent.

O: the number of cracks is 0

X: the number of cracks is 1 or more

(electrolyte permeability)

A sheet-like test piece was produced from the injection-molded article (40 mm. Times.40 mm. Times.0.5 mmt) after the sheet-like injection-molded article was left at 60℃for 24 hours. In the test cup (penetration area 7.065 cm) ² ) 5.5g of dimethyl carbonate (DMC) was placed therein, covered with a sheet-like test piece, and fastened and sealed with a PTFE gasket interposed therebetween. The pellet was allowed to contact DMC, kept at 60℃for 60 days, and then taken out, and left at room temperature for 1 hour to measure the mass reduction. The electrolyte permeability (g/m) was determined by ² )。

Electrolyte permeability (g/m) ² ) =mass reduction (g)/transmission area (m ² )

(abrasion test)

Test pieces of 10 cm. Times.10 cm were cut out from the sheet-like injection-molded bodies (155 mm. Times.100 mm. Times.2 mmt). The test piece thus prepared was fixed on a test stand of a taber abrasion tester (No. 101 model taber abrasion tester, manufactured by An Tian refiner manufacturing company), and abrasion test was performed using the taber abrasion tester under conditions of a test piece surface temperature of 150 ℃, a load of 500g, an abrasion wheel CS-10 (20 revolutions ground with grinding paper # 240), and a rotational speed of 60 rpm. The test piece weight after 1000 revolutions was measured, and the test piece weight was further measured after 8000 revolutions with the same test piece. The abrasion loss was determined by the following formula.

Abrasion loss (mg) =m1-M2

M1: test piece weight after 1000 revolutions (mg)

M2: test piece weight (mg) after 8000 revolutions

(tensile Strength after 10 ten thousand cycles)

The tensile strength after 10 ten-thousand cycles was measured by using a fatigue tester MMT-250NV-10 manufactured by Shimadzu corporation. A dumbbell-shaped sample (thickness 2.4mm, width 5.0mm, measuring section length 22 mm) was prepared using a sheet-like injection molded article (180 mm. Times.60 mm. Times.2.4 mmt) and an ASTM D1708 micro dumbbell. The sample was mounted on a measurement jig, and the measurement jig was set in a constant temperature bath at 150 ℃. Repeatedly proceeding to uniaxial direction with stroke of 0.2mm and frequency of 100HzThe tensile strength of each of the stretches (tensile strength at +0.2mm in stroke; tensile strength after 10 ten thousand cycles was calculated from the measured values according to the following formula; in this example, the cross-sectional area of the sample was 12.0 mm) ² 。

Tensile Strength after 10 ten thousand cycles (mN/mm) ² ) =tensile strength (10 ten thousand times) (mN)/cross-sectional area (mm) of sample ² )

The tensile strength after 10 ten thousand cycles is the ratio of the tensile strength under 10 ten thousand repeated loads to the cross-sectional area of the sample. The sheet having high tensile strength after 10 ten thousand cycles maintains high tensile strength even after 10 ten thousand loads, and is excellent in durability against repeated loads.

(mold Corrosion test)

20g of pellets were placed in a glass vessel (50 ml screw tube), and a metal column (5 mm square, 30mm in length) formed of HPM38 (Cr-plated) or HPM38 (Ni-plated) was suspended in the glass vessel so as not to contact the pellets. The glass container was then covered with aluminum foil. The glass container was put in an oven in this state and heated at 380℃for 3 hours. Then, the heated glass vessel was taken out of the oven, cooled to room temperature, and the degree of corrosion of the metal column surface was visually observed. The degree of corrosion was determined according to the following criteria.

O: no corrosion was observed

Delta: corrosion was slightly observed

X: corrosion was observed

Experimental example 7 to Experimental example 12 and comparative Experimental example 6 to comparative Experimental example 10

The copolymer described in Table 5 was injection molded using an injection molding machine (SE 50EV-A, manufactured by Sumitomo mechanical industries Co., ltd.) with Sup>A barrel temperature of 380℃and Sup>A mold temperature of 200℃and an injection speed of 10 mm/s. As the die, a die (spiral flow, width 10mm, thickness 0.5mmt, 1mmt, or 3 mmt) on which Cr plating was performed on HPM38 was used. The length (flow length) of the obtained injection molded article was measured, and the ratio of the flow length to the thickness (flow length/thickness) was calculated. The appearance of the obtained injection-molded article was visually observed and evaluated according to the following criteria. The results are shown in Table 5.

And (2) the following steps: smooth surface, excellent transparency, and beautiful impression

Delta: poor appearance such as off-white was observed in the range of 10% or less of the surface, but the remaining range of the surface was smooth and excellent in transparency

X: poor appearance such as off-white was observed in the range exceeding 10% of the surface

Further, the distance (maximum flow length (a)) from the gate portion of the injection-molded article obtained to the end portion of the injection-molded article was measured. Next, the minimum diameter of the cross section of the injection-molded body (product thickness on the maximum flow length) orthogonal to the line drawn for measuring the maximum flow length was measured every 2mm along the line drawn for measuring the maximum flow length, and the measured values were integrated to calculate the average of the measured values, thereby obtaining the average value (b) and the ratio ((a)/(b)) of the product thickness on the maximum flow length. The results are shown in Table 5.

Experimental example 13 to Experimental example 15

The copolymer described in Table 6 was injection molded using an injection molding machine (SE 50EV-A, manufactured by Sumitomo mechanical industries Co., ltd.) at Sup>A cylinder temperature of 400℃and Sup>A mold temperature of 200℃and an injection speed of 30mm/s, to obtain an injection molded article. As the mold, a mold (flat plate, 155mm×100mm, thickness 1.5mmt, 2-point side gate, gate set at positions 25mm and 75mm from the end of the 100mm side) in which Cr plating was performed on HPM38 was used. In the injection molded article obtained, a welded portion is formed at the welded portion at the center between the gates. The deeper the weld is formed closer to the gate, and the shallower the weld is formed further away from the gate.

As shown in fig. 1, a plurality of micro dumbbell-shaped test pieces shown in fig. 2 were produced by punching test pieces from the injection-molded body 10 in order along the welded portion 12 with a dumbbell cutter 13 centered on the welded portion 12 at the center of 2 positions 11 of the obtained injection-molded body 10 corresponding to the gate of the mold.

The welding depth (corresponding to the "maximum depth of the welded portion (D)") on the gate side of the welded portion located at the center of the micro dumbbell-shaped test piece was measured, and the ratio (welding ratio (D/L)) of the maximum depth of the welded portion (D) to the maximum thickness (L) (1.5 mmt in this experimental example) of the micro dumbbell-shaped test piece was determined.

Tensile test Using a Tensilon Universal tester (RTC-1225A manufactured by ORIENTEC), a tensile test was performed at a chuck spacing of 22mm and a tensile speed of 50mm/min, and the maximum point stress (tensile strength) was measured.

The relationship between the weld ratio (D/L) and the tensile strength is shown in Table 6.

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Claims (9)

1. An injection-molded article obtained by injection-molding a copolymer using a mold having a gate, wherein,

the copolymer contains Tetrafluoroethylene (TFE) units and fluoro (alkyl vinyl ether) (FAVE) units,

the content of the fluoro (alkyl vinyl ether) unit of the copolymer is 5.2 to 6.3 mass% relative to the total monomer units,

The melt flow rate of the copolymer at 372 ℃ is 19.0g/10 min-35.0 g/10 min,

every 10 of the copolymer ⁶ The number of functional groups having the number of carbon atoms in the main chain is 50 or less,

the injection-molded body has a gate portion corresponding to the gate of the mold, and the ratio of the maximum flow length a of the injection-molded body from the gate portion to the average value b of the product thickness over the maximum flow length, that is, a/b, is 80 to 200.

2. The injection-molded body according to claim 1, wherein the fluoro (alkyl vinyl ether) unit of the copolymer is a perfluoro (propyl vinyl ether) unit.

3. The injection-molded article according to claim 1 or 2, wherein the content of the fluoro (alkyl vinyl ether) unit of the copolymer is 5.4 to 6.1 mass% relative to the total monomer units.

4. An injection molded body according to any one of claims 1 to 3, wherein the copolymer has a melt flow rate at 372 ℃ of 20.0g/10 min to 30.9g/10 min.

5. The injection-molded article according to any one of claims 1 to 4, wherein the copolymer has a melting point of 295℃to 305 ℃.

6. The injection-molded article according to any one of claims 1 to 5, further comprising a welded portion, wherein a ratio of a maximum depth D to a maximum thickness L of the welded portion of the injection-molded article, that is, D/L is 0.8 or less.

7. A method for producing an injection-molded article according to any one of claims 1 to 6, comprising the step of injection-molding the copolymer using an injection molding machine and the mold having the gate,

the ratio of the maximum flow length c of the mold from the gate portion to the average value d of the cavity thickness of the mold over the maximum flow length, that is, c/d, is 80 to 200.

8. The manufacturing method according to claim 7, wherein the temperature of the mold is 150 ℃ to 250 ℃.

9. The production method according to claim 7 or 8, wherein a cylinder temperature of the injection molding machine is 350 ℃ to 420 ℃.