CARBON FIBER-CONTAINING POLYPROPYLENE COMPOSITION

Abstract

Provided is a fiber-reinforced polypropylene composition having a light weight and improved mechanical strength. A carbon fiber-containing polypropylene composition contains a predetermined amount of each of polypropylene (component 1), carbon fiber (component 2), and modified polypropylene (component 3), wherein the component 2 contains a predetermined amount of each of a C—O bond, a C═O bond, an O—C═O bond, a C—C bond, and a C—N bond.

Claims

1. A carbon fiber-containing polypropylene composition comprising: polypropylene (component 1), carbon fiber (component 2), and modified polypropylene (component 3), and satisfying all of the following requirements: Requirement 1: a content of the component 1, a content of the component 2, and a content of the component 3 are 30 to 98 wt %, 1 to 50 wt %, and 1 to 20 wt %, respectively, with respect to 100 wt % of a total weight of the component 1, the component 2, and the component 3; and Requirement 2-1: the component 2 contains a C—O bond, a C═O bond, an O—C═O bond, a C—C bond, and a C—N bond, and a content of the C—O bond is 1 to 24% with respect to 100% of a total spectrum area of the C—O bond, the C═O bond, the O—C═O bond, the C—C bond, and the C—N bond.

2. A carbon fiber-containing polypropylene composition comprising: polypropylene (component 1), carbon fiber (component 2), and modified polypropylene (component 3), and satisfying all of the following requirements: Requirement 1: a content of the component 1, a content of the component 2, and a content of the component 3 are 30 to 98 wt %, 1 to 50 wt %, and 1 to 20 wt %, respectively, with respect to 100 wt % of a total weight of the component 1, the component 2, and the component 3; and Requirement 2-2: the component 2 contains a C—O bond, a C═O bond, an O—C═O bond, a C—C bond, and a C—N bond, and a total content of the C═O bond and the O—C═O bond is 4 to 15% with respect to 100% of a total spectrum area of the C—O bond, the C═O bond, the O—C═O bond, the C—C bond, and the C—N bond.

3. A carbon fiber-containing polypropylene composition comprising: polypropylene (component 1), carbon fiber (component 2), and modified polypropylene (component 3), and satisfying all of the following requirements: Requirement 1: a content of the component 1, a content of the component 2, and a content of the component 3 are 30 to 98 wt %, 1 to 50 wt %, and 1 to 20 wt %, respectively, with respect to 100 wt % of a total weight of the component 1, the component 2, and the component 3; and Requirement 2-3: the component 2 contains a C—O bond, a C═O bond, an O—C═O bond, a C—C bond, and a C—N bond, and a content of the C—O bond and a total content of the C═O bond and the O—C═O bond are 1 to 24% and 4 to 15%, respectively, with respect to 100% of a total spectrum area of the C—O bond, the C═O bond, the O—C═O bond, the C—C bond, and the C—N bond.

4. The carbon fiber-containing polypropylene composition according to claim 1, wherein the component 3 is at least one modified polypropylene selected from the group consisting of maleic anhydride-modified polypropylene, epoxy-modified polypropylene, and carbodiimide-modified polypropylene.

5. A molded article comprising the carbon fiber-containing polypropylene composition according to claim 1.

6. The carbon fiber-containing polypropylene composition according to claim 2, wherein the component 3 is at least one modified polypropylene selected from the group consisting of maleic anhydride-modified polypropylene, epoxy-modified polypropylene, and carbodiimide-modified polypropylene.

7. The carbon fiber-containing polypropylene composition according to claim 3, wherein the component 3 is at least one modified polypropylene selected from the group consisting of maleic anhydride-modified polypropylene, epoxy-modified polypropylene, and carbodiimide-modified polypropylene.

8. A molded article comprising the carbon fiber-containing polypropylene composition according to claim 2.

9. A molded article comprising the carbon fiber-containing polypropylene composition according to claim 3.

10. A molded article comprising the carbon fiber-containing polypropylene composition according to claim 4.

11. A molded article comprising the carbon fiber-containing polypropylene composition according to claim 6.

12. A molded article comprising the carbon fiber-containing polypropylene composition according to claim 7.

Description

EXAMPLES

[0217] Hereinafter, the present disclosure will be described in more detail with reference to Examples and Comparative Examples, but the present disclosure is not limited thereto.

[0218] Method of Calculating Bond Component in Surface of Carbon Fiber

[0219] Removal of Sizing Agent

[0220] A temperature of an accelerated solvent extractor ASE-200 (manufactured by Nippon Dionex K.K.) was set to 80° C., and then 0.2 g of carbon fiber was placed in an extraction cell container having a volume of 11 ml and installed in the accelerated solvent extractor ASE-200. 11 ml of tetrahydrofuran (manufactured by Kanto Chemical Co., Inc., special grade, containing no stabilizer) was injected to the extraction cell container, and then the pressure in the extraction cell container was pressurized to 1,000 psi and held for 15 minutes. About half of the tetrahydrofuran was expelled through a discharge port of the extraction cell container using nitrogen, tetrahydrofuran was injected again until the amount of tetrahydrofuran in the extraction cell container reached 11 ml, and then the pressure in the extraction cell container was pressurized to 1,000 psi and held for 10 minutes. About half of the tetrahydrofuran was expelled once again through the discharge port of the extraction cell container using nitrogen, tetrahydrofuran was injected again until the amount of tetrahydrofuran in the extraction cell container reached 11 ml, and then the pressure in the extraction cell container was pressurized to 1,000 psi and held for 10 minutes. Thereafter, nitrogen was injected to the extraction cell container for 2 minutes, and the tetrahydrofuran was expelled through the discharge port of the extraction cell container. The carbon fiber was removed from the extraction cell container and vacuum drying was performed at 40° C. for at least 15 hours.

[0221] X-Ray Photoelectron Spectroscopy (XPS) Analysis

[0222] Next, the carbon fiber subjected to the above work was installed in an X-ray photoelectron spectrometer (manufactured by Shimadzu-Kratos Corp., AXIS ULTRA DLD). A monochromatic Al Kα (1,486.6 eV) was used as an X-ray source and used as excitation light. A tube current was set to 10 mA, a tube voltage was set to 15 kV, and a photoelectron take-off angle defined by an angle between a normal direction of the sample and a photoelectron take-off direction was set to 0°, thereby measuring an output. A background of the obtained carbon is spectrum was removed by the Shirley method.

[0223] The carbon is spectrum from which the background was removed was waveform-separated for a peak derived from each of a C—C bond component, a C—N bond component, a C—O bond component, a C═O bond component, and an O—C═O bond component, by using a Gauss-Lorentz complex function in which a ratio of a Lorentz function was set to 30%, according to a method described in Composites: Part A 90 (2016) 653-661 (Bo Gao et al.).

[0224] A spectrum area of each of the C—C bond component, the C—N bond component, the C—O bond component, the C═O bond component, and the O—C═O bond component obtained by the waveform separation was determined, and a ratio of the spectrum area of the C—O bond component and a ratio of a total amount of the spectrum area of the C═O bond component and the spectrum area of the O—C═O bond component with respect to 100% of a total amount of the C—C bond component, the C—N bond component, the C—O bond component, the C═O bond component, and the O—C═O bond component were calculated.

[0225] Synthesis Example of Modified Polypropylene

[0226] Maleic Anhydride-Modified Polypropylene-1

[0227] Synthesis Example 2 described in WO 2020/009090 A was used.

[0228] Carbodiimide-Modified Polypropylene-1

[0229] 100 wt % of the maleic anhydride-modified polypropylene-1 synthesized in the above, 1.7 wt % of a carbodiimide group-containing compound (manufactured by Nisshin Boseki Co., Ltd., trade name: Carbodilite (registered trademark) HMV-15CA (carbodiimide equivalent: 262 g/mol)), 0.2 wt % of an antioxidant 1 (manufactured by Sumitomo Chemical Co., Ltd., Sumilizer GA80), and 0.2 wt % of an antioxidant 2 (manufactured by Sumitomo Chemical Co., Ltd., Sumilizer GP) were mixed with each other, and the mixture was melted and kneaded with a twin-screw kneader (manufactured by TECHNOVEL Corporation, KZW-15, screw diameter: 15 mm, L/D=45, cylinder temperature: 250° C., rotation speed: 300 rpm, discharge: 2 kg/hr) while degassing from a vacuum vent, thereby obtaining carbodiimide-modified polypropylene-1. An MFR (230° C. and load of 2.16 kg) of the obtained carbodiimide-modified polypropylene-1 was 18 g/10 min.

[0230] Epoxy-Modified Polypropylene-1

[0231] 100 wt % of the maleic anhydride-modified polypropylene-1 synthesized in the above, 0.67 wt % of an epoxy group-containing compound (manufactured by Nissan Chemical Industries, Ltd., trade name: TEPIC-S (epoxy equivalent: 105 g/eq), 0.2 wt % of an antioxidant 1, and 0.2 wt % of an antioxidant 2 were mixed with each other, and the mixture was melted and kneaded with a twin-screw kneader (manufactured by TECHNOVEL Corporation, KZW-15, screw diameter: 15 mm, L/D=45, cylinder temperature: 250° C., rotation speed: 300 rpm, discharge: 2 kg/hr) while degassing from a vacuum vent, thereby obtaining epoxy-modified polypropylene-1. An MFR (230° C. and load of 2.16 kg) of the obtained epoxy-modified polypropylene-1 was 69 g/10 min.

[0232] Carbon Fiber 2

[0233] About 10 g of CFRI T8S103C (manufactured by Carbon Fiber Recycle Industry Co., Ltd.) was weighed and put into a 100 mL magnetic crucible, and the magnetic crucible was charged into an electric furnace (manufactured by TT-Labo Co., LTD., TFD-20C-Z). The electric furnace was heated from room temperature to 500° C. at about 65° C./min and was allowed at 500° C. for 1 hour, thereby obtaining carbon fiber 2.

[0234] The obtained carbon fiber 2 was subjected to removal of a sizing agent by the method described above. As a result of measuring a content of the C—O bond and a total content of the C═O bond and the O—C═O bond by the method described above, the content of the C—O bond was 19.3%, and the total content of the C═O bond and the O—C═O bond was 11.3%.

[0235] Used Materials

[0236] The following materials were used in Examples and Comparative Examples.

[0237] 1. Polypropylene (Component 1)

[0238] Polypropylene homopolymer 1 (manufactured by Sumitomo Chemical Co., Ltd., NOBLEN HR100EG)

[0239] MFR (230° C., load of 21.2 N): 23 g/10 min

[0240] Melting point: 164° C.

[0241] Polypropylene homopolymer 2 (manufactured by Sumitomo Chemical Co., Ltd., NOBLEN HU100EG)

[0242] MFR (230° C., load of 21.2 N): 100 g/10 min

[0243] Melting point: 164° C.

[0244] 2. Carbon Fiber (Component 2)

[0245] Carbon fiber 1 (manufactured by Carbon Fiber Recycle Industry Co., Ltd., CFRI T8S103C)

[0246] C—O bond: 5.2%, total of C═O bond and O—C═O bond: 5.8%

[0247] Carbon fiber 2 (obtained by performing heat treatment on carbon fiber-1 at 500° C. for 1 hour)

[0248] C—O bond: 19.3%, total of C═O bond and O—C═O bond: 11.3%

[0249] Carbon fiber 3 (manufactured by Teijin Limited, Tenax-A PCS171200)

[0250] C—O bond: 14.2%, total of C═O bond and O—C═O bond: 7.3%

[0251] Carbon fiber 4 (manufactured by Teijin Limited, Tenax-J IM C443)

[0252] C—O bond: 24.7%, total of C═O bond and O—C═O bond: 2.7%

[0253] Carbon fiber 5 (manufactured by SGL CARBON JAPAN Co., Ltd., SIGRAFIL C C6-4.0/240-T130)

[0254] C—O bond: 27.4%, total of C═O bond and O—C═O bond: 3.1%

[0255] 3. Modified Polypropylene (Component 3)

[0256] Modified Polypropylene 1

[0257] The maleic anhydride-modified polypropylene of Synthesis Example

[0258] Modified Polypropylene 2

[0259] The Carbodiimide-Modified Polypropylene of Synthesis Example

[0260] Modified polypropylene 3

[0261] The Epoxy-Modified Polypropylene of Synthesis Example

[0262] 4. Other Materials

[0263] Antioxidant 3: manufactured by BASF Japan Ltd., Irganox 1010

[0264] Antioxidant 4: manufactured by BASF Japan Ltd., Irgafos 168

[0265] Melting and Kneading and Production of Injection Molded Article

Example 1

[0266] 70 wt % of the polypropylene homopolymer 1, 10 wt % of the modified polypropylene 1, 20 wt % of the carbon fiber 1, and 0.2 parts by weight of the antioxidant 3 and 0.2 parts by weight of the antioxidant 4 with respect to 100 parts by weight of a total of the polypropylene homopolymer 1, the modified polypropylene 1, and the carbon fiber 1 were mixed with each other to obtain a mixture. The mixture was melted and kneaded with a 40 mm single screw extruder (VS40-28 bent type extruder, manufactured by TANABE PLASTICS MACHINERY CO., LTD.) at a cylinder temperature of 220° C. and a screw rotation speed of 100 rpm, and the mixture was pelletized, thereby obtaining a carbon fiber-containing polypropylene composition. The obtained carbon fiber-containing polypropylene composition was subjected to injection molding using an injection molding machine (manufactured by Meiki Co., Ltd., M-70CSJ) under conditions of a cylinder temperature of 220° C., a mold temperature of 50° C., and an injection speed of 20 mm/sec, thereby obtaining an injection molded article of an ISO test piece.

Examples 2 to 8 and Comparative Examples 1 to 4

[0267] Carbon fiber-containing polypropylene compositions of Examples 2 to 8 and Comparative Examples 1 to 4 were produced in the same manner as that of Example 1 except that the materials shown in Table 1 were used.

[0268] Evaluation of Physical Properties

[0269] 1. Melt Mass Flow Rate (Unit: g/10 min)

[0270] A melt mass flow rate was measured at a measurement temperature of 230° C. and a load of 2.16 kg according to a method specified in JIS K 7210.

[0271] 2. Density (Unit: g/cm.sup.3)

[0272] Using the molded article molded by the molding method described in “Melting and Kneading and Production of Injection Molded Article” and cut into a size of 80 mm×10 mm×4 mm as a test piece, a density was measured according to a water replacement method which is the A method specified in JIS K7112.

[0273] 3. Ultimate tensile Break Strength (Unit: MPa)

[0274] Using the test piece having a thickness of 4 mm molded by the molding method described in “Melting and Kneading and Production of Injection Molded Article”, a ultimate tensile break strength (US) was measured at a tensile speed of 50 mm/min according to a method specified in ISO 527-2.

[0275] 4. Flexural Strength (Unit: MPa)

[0276] Using the test piece having a thickness of 4 mm molded by the molding method described in “Melting and Kneading and Production of Injection Molded Article”, a flexural strength (FS) was measured at a loading speed of 2.0 mm/min according to a method specified in ISO 178.

TABLE-US-00001 TABLE 1 Carbon fiber Total (%) of C═O and Example C—O(%) O—C═O 1 2 3 4 5 Component Polypropylene 70 70 70 70 1 homopolymer 1 Polypropylene 70 homopolymer 2 Component Carbon fiber 1 5.2 5.8 20 20 20 20 2 Carbon fiber 2 19.3 11.3 20 Carbon fiber 3 14.2 7.3 Carbon fiber 4 24.7 2.7 Carbon fiber 5 27.4 3.1 Component Modified polypropylene 10 10 10 3 1 Modified polypropylene 10 2 Modified polypropylene 10 3 Ultimate tensile strength (MPa) 121 130 131 131 130 Flexural strength (MPa) 169 179 175 183 178 Density (g/cm.sup.3) 0.993 0.991 0.996 0.993 0.994 MFR (g/10 min) 2.3 11 2.9 2.1 1.7 Example Comparative Example 6 7 8 1 2 3 4 Component Polypropylene 70 90 90 80 70 70 90 1 homopolymer 1 Polypropylene homopolymer 2 Component Carbon fiber 1 5 20 2 Carbon fiber 2 Carbon fiber 3 20 5 Carbon fiber 4 20 Carbon fiber 5 20 5 Component Modified polypropylene 10 5 5 10 10 5 3 1 Modified polypropylene 2 Modified polypropylene 3 Ultimate tensile strength (MPa) 129 63 70 83 109 75 44 Flexural strength (MPa) 184 87 95 119 147 94 64 Density (g/cm.sup.3) 0.994 0.927 0.927 0.994 0.994 0.996 0.929 MFR (g/10 min) 2.8 10 7.9 1.7 0.9 1.8 7.7