FLUORORESIN, LAMINATE, TUBE, AND TUBE MANUFACTURING METHOD

Abstract

A fluororesin having a reactive functional group, wherein the difference between the loss elastic modulus at 270° C. of the fluororesin (G″.sub.270) and the loss elastic modulus at 280° C. of the fluororesin (G″.sub.280) (G″.sub.270-G″.sub.280) is 2,500 Pa or more. Also disclosed is a fluororesin layer containing the fluororesin; and a non-fluororesin layer containing a non-fluororesin.

Claims

1. A fluororesin having a reactive functional group, wherein a difference between a loss elastic modulus at 270° C. of the fluororesin (G″.sub.270) and a loss elastic modulus at 280° C. of the fluororesin (G″.sub.280) (G″.sub.270-G″.sub.280) is 2,500 Pa or more.

2. The fluororesin according to claim 1, wherein the difference between the storage elastic modulus at 270° C. of the fluororesin (G′.sub.270) and the storage elastic modulus at 280° C. of the fluororesin (G′.sub.280) (G′.sub.270-G′.sub.280) is 1,500 Pa or more.

3. The fluororesin according to claim 1, wherein the fluororesin is a melt-fabricable fluororesin.

4. The fluororesin according to claim 1, wherein the fluororesin contains ethylene unit and tetrafluoroethylene unit.

5. The fluororesin according to claim 4, wherein the fluororesin further contains hexafluoropropylene unit.

6. The fluororesin according to claim 1, wherein the number of reactive functional groups of the fluororesin is 3 or more per 10.sup.6 main-chain carbon atoms.

7. A laminate comprising: a fluororesin layer containing the fluororesin according to claim 1; and a non-fluororesin layer containing a non-fluororesin.

8. The laminate according to claim 7, comprising a polyamide resin layer containing a polyamide resin as the non-fluororesin layer.

9. The laminate according to claim 7, comprising an ethylene/vinyl alcohol copolymer (EVOH) layer containing an EVOH resin as the non- fluororesin layer.

10. The laminate according to claim 7, comprising: a polyamide resin layer containing a polyamide resin and an ethylene/vinyl alcohol copolymer (EVOH) layer containing an EVOH resin as the non-fluororesin layer, wherein the fluororesin layer and the polyamide resin layer are directly adhered and the polyamide resin layer and the EVOH layer are directly adhered.

Description

EXAMPTES

[0196] Next, embodiments of the present disclosure will now be described by way of Examples, but the present disclosure is not limited solely to the Examples.

[0197] The numerical values of the Examples were measured by the following methods.

<Polymer Composition>

[0198] .sup.19F-NMR measurement was conducted using pellets of the fluororesin obtained in each Example and a nuclear magnetic resonance apparatus AC300 (manufactured by Bruker-Biospin AG) to determine the polymer composition from the integrated values of peaks. Depending on the kind of monomer, the results of elemental analysis were suitably combined to determine the polymer composition (the content of each monomer unit of the polymer).

<Melting Point>

[0199] Thermal measurement was conducted using pellets of the fluororesin obtained in each Example and a differential scanning calorimeter REC220 (manufactured by Seiko Instruments Inc.) in accordance with ASTM D 4591 at a temperature-increasing rate of 10° C./min, and the melting point of the fluororesin was determined from the peak of the endothermic curve obtained.

<Melt Flow Rate (MFR)>

[0200] The mass (g/10 min) of the fluororesin flowing out from a nozzle having an inner diameter of 2 mm and a length of 8 mm per 10 minutes at 265° C. or 297° C. under a load of 5 kg was determined as the MFR using pellets of the fluororesin obtained in each Example and a melt indexer (manufactured by Yasuda Seiki Seisakusho Ltd.) in accordance with ASTM D 1238.

<Number of Carbonate Groups and Carboxylic Acid Fluoride Groups>

[0201] Pellets of the fluororesin obtained in each Example were compression-molded at room temperature to produce films having a thickness of 50 to 200 wt. In an infrared absorption spectrum analysis of this film, a peak assigned to the carbonyl group of a carbonate group [—OC(═O)O—] appears at an absorption wavelength of 1817 cm.sup.−1 [ν.sub.(C═))], and a peak assigned to the carbonyl group of a carboxylic acid fluoride group [—COF] appears at an absorption wavelength of 1884 cm.sup.−1 [ν.sub.(C═O)], and thus the absorbance of the ν.sub.(C═O)peaks was measured. The number of carbonate groups per 10.sup.6 main-chain carbon atoms of the fluororesin was calculated according to the following formula.

Number of carbonate groups or carboxylic acid fluoride groups (per 10.sup.6 main-chain carbon atoms)=(l×K)/t [0202] l: Absorbance [0203] K: Correction factor (—OC(═O)O—R: 1426, —COF: 405) [0204] t: Film thickness (min)

[0205] The infrared absorption spectrum analysis was conducted by scanning 40 times using a Perkin-Elmer MIR spectrometer 1760× (manufactured by The Perkin-Elmer Corporation). The obtained IR spectrum was subjected to automatic baseline judgment by Perkin-Elmer Spectrum for Windows Ver. 1.4C to measure the absorbance of the peaks at 1817 cm.sup.−1 and 1884 cm.sup.−1. The thickness of the films was measured with a micrometer gauge.

<Loss Elastic Modulus (G″) and Storage Elastic Modulus (G′)>

[0206] Pellets of the fluororesin obtained in each Example were used to produce a sheet having a thickness of 2 mm by compression molding at 210° C., and the sheet was subjected to melt viscoelasticity measurement. Using a 25ϕ parallel plate as the jig for measurement, the sample was set to a melt viscoelasticity measurement apparatus at 210° C. The thickness during measurement is 0.8 mm. While measurement was conducted at a strain of 0.1% and 10 rad/second every 30 seconds, heating was made from 210° C. to 300° C. at a rate of 2° C./min. At the time point at which 270° C. has been reached, the loss elastic modulus is defined as G″.sub.270, and the storage elastic modulus is defined as G′.sub.270. At the time point at which 280° C. has been reached, the loss elastic modulus is defined as G″.sub.280, and the storage elastic modulus was defined as G′.sub.280.

Example 1 (Production of fluororesin A)

[0207] 380 L of distilled water was placed in an autoclave. After sufficient nitrogen purging, 166 kg of octafluorocyclobutane, 83 kg of HFP, and 0.3 kg of perfluoro(1,1,5-trihydro-1-pentene) (CH.sub.2═CF(CF.sub.2).sub.3H) were loaded, and the inside of the system was kept at 35° C. and a stirring speed of 200 ipm. Thereafter, TFE was injected up to 0.87 MPa, and further subsequently, Et was injected up to 0.95 MPa. Then, 6.3 kg of di-n-propyl peroxydicarbonate was placed, and polymerization was started. The pressure inside the system decreases as the progress of the polymerization, and thus a gas mixture of TFE/Et/HFP=46/44/10 mol % was continuously supplied to keep the pressure inside the system at 0.95 MPa. Then, perfluoro(1,1,5-trihydro-1-pentene) was continuously loaded up to a total amount of 3.2 kg, and stirring was continued for 23 hours. The pressure was released to atmospheric pressure, and the reaction product was recovered.

[0208] The obtained reaction product was cleaned and dried to obtain 250 kg of a powdery fluororesin. The powdery fluororesin was famed using a single screw extruder to obtain pellets of the fluororesin A.

[0209] The fluororesin A had the following physical properties. [0210] TFE/ethylene/HFP/perfluoro(1,1,5-trihydro-1-pentene) copolymer [0211] TFE/ethylene/HFP/perfluoro(1,1,5-trihydro-1-pentene)=45.5/44.4/9.5/0.6 (mol %) [0212] Melting point: 197° C. [0213] Melt flow rate (265° C.): 28.9 g/10 min [0214] Number of carbonate groups and carboxylic acid fluoride groups: 314/10.sup.6C [0215] Loss elastic modulus at the time point at which 270° C. has been reached (G″.sub.270): 11,815 Pa [0216] Difference (G″.sub.270-G″.sub.280): 4,455 Pa [0217] Storage elastic modulus at the time point at which 270° C. has been reached (G′.sub.270): 5,058 Pa [0218] Difference (G′.sub.270-G′.sub.280): 2,148 Pa

[0219] Laminates to be obtained by using the produced pellets of fluororesins A will be described with reference to Examples. The physical properties of the laminates were measured by the following methods.

<Adhesive Strength>

[0220] A 1 cm-width test piece was cut off from the tube obtained in each Example and subjected to a 180° delamination test at a speed of 25 mm/min using a Tensilon Universal Tester. The average of 5 local maximum points in the elongation amount−tensile strength graph was determined as the adhesive strength (N/cm).

<Surface Roughness Ra>

[0221] A test piece was produced by cutting the tube obtained in each Example, and the surface roughness Ra was measured at a point of the test piece corresponding to the inner surface of the tube. Measurement at 5 measurement points was repeated 3 times using a surface roughness measuring machine (SURFTEST SV-600 manufactured by Mitutoyo Corporation) in accordance with JIS B0601-1994, and the average of the obtained measurements was defined as the surface roughness Ra.

<Thickness Unevenness>

[0222] The thickness at a total of 10 points at an every 1-m interval from an arbitrary point of the tube obtained in each Example was measured using a micrometer gauge. The proportion of the difference between the maximum value and the minimum value of the measured thickness with respect to the maximum value of the thickness (%) (=[(maximum value)−(minimum value)]/(maximum value)×100) was calculated.

[0223] In Examples, the following materials were used in addition to the fluororesin A.

Polyamide 12

[0224] Vestamid X7297 manufactured by Daicel-Evonik Ltd.

Polyamide 612

[0225] Vestamid SX8002 manufactured by Daicel-Evonik Ltd. Ethylene/vinyl alcohol copolymer resin

[0226] F101B manufactured by Kuraray Co., Ltd.

Example 2 to 3 (Production of Laminate)

[0227] Using a two-component two-layer tube extrusion apparatus equipped with a multimanifold (manufactured by PLABOR Research Laboratory of Plastics Technology Co., Ltd.), polyamide 12 as a layer (B) and the fluororesin A as a layer (A) were fed to two extruders, respectively, to mold a two-component two-layer multilayer tube having an outer diameter of 8 mm and an inner diameter of 6 mm, according to the extrusion conditions shown in Table 2. The multilayer tube has a layer arrangement of the layer (A)/layer (B), and the layer (A) is the innermost layer. The evaluation results are shown in Table 2.

Examples 4 to 5 (Production of Laminate)

[0228] Using a five-component five-layer tube extrusion apparatus equipped with a multimanifold (manufactured by PLABOR Research Laboratory of Plastics Technology Co., Ltd.), polyamide 12 as a layer (E), polyamide 612 as layers (B and D), an ethylene/vinyl alcohol copolymer resin as a layer (C), and the fluororesin A as a layer (A) were fed to five extruders, respectively, to mold a 5-component 5-layer multilayer tube having an outer diameter of 8 mm and an inner diameter of 6 mm, according to the extrusion conditions shown in Table 2. The multilayer tube has a layer arrangement of the layer (A)/layer (B)/layer (C)/layer (D)/layer (E), and the layer (A) is the innermost layer. The evaluation results are shown in Table 2.

TABLE-US-00002 TABLE 2 Example Example Example Example 2 3 4 5 Layer Cylinder 260-270 260-270 260-270 260-270 (A) temperature (° C.) Adapter 270 270 270 270 temperature (° C.) Layer Cylinder 210-245 210-246 230-260 230-260 (B) temperature (° C.) Adapter 245 245 260 280 temperature (° C.) Layer Cylinder 200-220 200-220 (C) temperature (° C.) Adapter 220 220 temperature (° C.) Layer Cylinder 230-260 230-260 (D) temperature (° C.) Adapter 260 280 temperature (° C.) Layer Cylinder 210-250 210-250 (E) temperature (° C.) Adapter 250 250 temperature (° C.) Die 270 270 270 270 temperature (° C.) Chip 280 280 280 280 temperature (° C.) Line Speed 20 70 20 70 (m/min) Layer (A) 250 250 100 100 Layer (B) 750 750 350 350 Thick- Layer (C) 150 150 ness Layer (D) 100 100 μm Layer (E) 300 300 Adhesive strength Material Material Material Material fracture fracture fracture fracture Surface roughness 0.03 0.04 0.12 0.15 Ra (μm) Thickness 0.6 1.1 0.8 1.5 unevenness (%)