Reinforcing fiber bundle and molding material

Abstract

Disclosed are: a reinforcing fiber bundle with excellent mechanical property and handling property, which contains a propylene-based resin (A), a propylene-based resin (B) comprising at least a carboxylic acid salt bonded to the polymer chain, and a reinforcing fiber (C) wherein the propylene-based resin (A) comprises more than 70% by mass but not more than 100% by mass of a component (A-1) having a weight average molecular weight of 150,000 or more, the amount of the propylene-based resin (B) is 3 to 50 parts by mass per 100 parts by mass of the propylene-based resin (A), and the total content rate of the propylene-based resin (A) and the propylene-based resin (B) is 0.3 to 5% by mass in the whole reinforcing fiber bundle; and a molding material comprising the reinforcing fiber bundle and a matrix resin.

Claims

1. A reinforcing fiber bundle which contains a propylene-based resin (A), a propylene-based resin (B) comprising at least a carboxylic acid salt bonded to the polymer chain, and a reinforcing fiber (C) wherein the propylene-based resin (A) comprises more than 70% by mass but not more than 100% by mass of a component (A-1) having a weight average molecular weight of 150,000 or more, and 0 to 30% by mass of a component (A-2) having a weight average molecular weight of less than 150,000, provided that the sum of the component (A-1) and the component (A-2) is 100% by mass, the weight average molecular weight of the propylene-based resin (A) is higher than the weight average molecular weight of the propylene-based resin (B), the amount of the propylene-based resin (B) is 3 to 50 parts by mass per 100 parts by mass of the propylene-based resin (A), and the total content of the propylene-based resin (A) and the propylene-based resin (B) is 0.3 to 5% by mass in the whole reinforcing fiber bundle.

2. The reinforcing fiber bundle according to claim 1, wherein the total content of the propylene-based resin (A) and the propylene-based resin (B) is 0.3 to 3% by mass in the whole reinforcing fiber bundle.

3. The reinforcing fiber bundle according to claim 1, wherein the propylene-based resin (A) has a Shore A hardness of 60 to 90 or a Shore D hardness of 45 to 65.

4. The reinforcing fiber bundle according to claim 1, wherein the propylene-based resin (A-1) comprises 0.0003 to 5% by mass of a group 15 to 17 element of the periodic table.

5. The reinforcing fiber bundle according to claim 4, wherein the propylene-based resin (A-1) comprises a maleic anhydride structure.

6. The reinforcing fiber bundle according to claim 1, which is a reinforcing fiber bundle for polyamide resin.

7. A molding material which contains 1 to 80 parts by mass of the reinforcing fiber bundle of claim 1 and, 20 to 99 parts by mass of a thermoplastic matrix resin (M), provided that the sum of the reinforcing fiber bundle and the matrix resin (M) is 100 parts by mass.

8. The molding material according to claim 7, which contains 10 to 70 parts by mass of the reinforcing fiber bundle and, 30 to 90 parts by mass of a propylene-based resin (D), provided that the sum of the reinforcing fiber bundle and the propylene-based resin (D) is 100 parts by mass, wherein the weight average molecular weight Mw (A) of the propylene-based resin (A), the weight average molecular weight Mw (B) of the propylene-based resin (B) and the weight average molecular weight Mw (D) of the propylene-based resin (D) satisfy the following relation:
Mw(A)>Mw(D)>Mw(B).

9. The molding material according to claim 7, which contains 1 to 80 parts by mass of the reinforcing fiber bundle and, 20 to 99 parts by mass of a polyamide resin (E), provided that the sum of the reinforcing fiber bundle and the polyamide resin (E) is 100 parts by mass.

10. A fiber-reinforced resin composition for tape winding molding which contains: (i) a polymer (I) comprising an olefin-derived unit having 2 to 20 carbon atoms and having a carboxylic acid group, and (ii) the reinforcing fiber bundle of claim 1, wherein the melting point and/or the glass transition temperature of the polymer (I) is 50 to 300 C., and wherein the amount of the polymer (I) is 20 to 80 parts by mass, and the amount of the reinforcing fiber (C) contained in the reinforcing fiber bundle is 20 to 80 parts by mass, provided that the sum of the polymer (I) and the reinforcing fiber (C) is 100 parts by mass.

11. A fiber-reinforced resin composition for tape winding molding which contains 25 parts by mass of the reinforcing fiber bundle of claim 1 and, 25 to 75 parts by mass of at least one resin selected from the group consisting of a propylene-based resin (D) and a polyamide resin (E), provided that the sum of the reinforcing fiber bundle and the at least one resin is 100 parts by mass.

12. The fiber-reinforced resin composition for tape winding molding according to claim 11, wherein the resin is the propylene-based resin (D).

13. The fiber-reinforced resin composition for tape winding molding according to claim 10, which further contains 5 parts by mass or less of a dye (II) absorbing a light having a wavelength of 300 to 3000 provided that the sum of the polymer (I) and the reinforcing fiber (C) is 100 parts by mass.

14. A laminated body having a layer containing the molding material of claim 7.

15. A tape winding molded article containing the laminated body according of claim 14.

16. A tape winding molding method using a tape containing the fiber-reinforced resin composition of claim 10.

17. The tape winding molding method according to claim 16, wherein the fiber-reinforced resin composition further contains 5 parts by mass or less of a dye (II) absorbing a light having a wavelength of 300 to 3000 m, provided that the sum of the polymer (I) and the reinforcing fiber (C) is 100 parts by mass.

Description

EXAMPLES

(1) Hereinafter, the present invention will be explained in more detail by examples.

(2) (1) Measurement of Adhesion Amount of Propylene-Based Resin to Reinforcing Fiber Bundle

(3) Approximately 5 g of a reinforcing fiber bundle carrying a propylene-based resin adhered thereto was taken and dried at 120 C. for 3 hours, and its weight W.sub.1 (g) was measured. Then, the reinforcing fiber bundle was heated in a nitrogen atmosphere at 450 C. for 15 minutes, thereafter, cooled to room temperature, and its weight W.sub.2 (g) was measured. Using W.sub.1 (g) and W.sub.2 (g), the adhesion amount was calculated by the following equation.
Adhesion amount=[(W.sub.1W.sub.2)/W.sub.2]100(% by mass)
(2) Measurement of Weight Average Molecular Weight of Propylene-Based Resin

(4) The molecular weight was determined by the GPC method under the following conditions.

(5) Liquid chromatograph: manufactured by Polymer Laboratories Ltd., PL-GPC220 type hot gel permeation chromatograph (differential refractometer device embedded)

(6) Column: manufactured by Tosoh Corporation, TSKgel GMH.sub.HR-H(S)-HT2 and GMH.sub.HR-H(S)1 connected in series

(7) Mobile phase medium: 1,2,4-trichlorobenzene (containing 0.025% stabilizer)

(8) Flow rate: 1.0 ml/min

(9) Measurement temperature: 150 C.

(10) Method for preparing calibration curve: A standard polystyrene sample was used.

(11) Sample concentration: 0.15% (w/v)

(12) Amount of sample solution: 500 l

(13) Standard sample for preparing calibration curve: Monodisperse polystyrene manufactured by Tosoh Corporation

(14) Molecular weight calibration method: Standard calibration method (polystyrene conversion)

(15) (3) Structure Analysis of Propylene-Based Resin

(16) Each propylene-based resin was subjected to organic compound elemental analysis, inductively coupled plasma (ICP) emission spectrometry, IR (infrared absorption) spectrum analysis, .sup.1H-NMR measurement and .sup.13C-NMR measurement, and the content rate of the monomer structure was evaluated from the amount of elements contained in the propylene-based resin, the identification of the structure of the functional group, the attribution proton and the peak intensity of carbon, Organic compound element analysis was carried out using an organic element analyzer 2400 II (manufactured by PerkinElmer). ICP emission spectrometry was carried out using ICPS-7510 (manufactured by Shimadzu Corporation). IR spectrum analysis was carried out using IR-Prestige-21 (manufactured by Shimadzu Corporation). .sup.1H-NMR measurement and .sup.13C-NMR measurement were carried out using a JEOL JNM-GX 400 spectrometer (manufactured by JEOL Ltd.).

(17) (4) Measurement of Carboxylic Acid Salt Content of Propylene-Based Resin

(18) For each propylene-based resin, the carboxylic acid salt content and the non-neutralized carboxylic acid content were measured by carrying out the following operation. Zero point five (0.5) g of the propylene-based resin was refluxed with heating in 200 ml of toluene and dissolved. This solution was titrated with a 0.1 N potassium hydroxide-ethanol standard solution, and the acid value was calculated by the following equation. Phenolphthalein was used as an indicator.
Acid value=(5.611AF)/B (mg KOH/g)

(19) A: Use amount (ml) of 0.1 N potassium hydroxide-ethanol standard solution

(20) F: Factor of 0.1 N potassium hydroxide-ethanol standard solution (1.02)

(21) B: Sampling amount (0.50 g)

(22) Next, the acid value calculated by the above method was converted into the number of moles of the carboxylic acid group not neutralized by the following formula.
Number of moles of carboxylic acid group not neutralized=acid value1,000/56 (mol/g)

(23) Then, the conversion rate of a carboxylic acid group to a neutralized salt is calculated by the following formula using the total number of moles (mol/g) of the carboxylic acid group calculated by separately quantifying carbonyl carbon of the carboxylic acid group by a method such as IR, NMR or elemental analysis.
Conversion rate %=(1r)100(%)

(24) r: Number of moles of carboxylic acid group not neutralized/total number of moles of carboxylic acid group

(25) (5) Measurement of Number of Fluffs Caused by Friction

(26) It was determined in the same manner as described in examples of Japanese Patent No. 5584977. Specifically, the number of fluffs caused by friction of 0 to 5 pieces/m was accepted, and the number over this was rejected.

(27) (6) Evaluation of Interfacial Shear Strength

(28) <Interfacial Shear Strength (IFSS)>

(29) The interfacial shear strength (fragmentation method) between the reinforcing fiber bundle and the matrix resin was evaluated by the following method. Two resin films (20 cm20 cm square) made of the matrix resin (M) and having a thickness of 100 m were produced. One single fiber of 20 cm length taken out from the reinforcing fiber bundle was arranged linearly on one resin film and the other resin film was placed so as to sandwich the single fiber therebetween. This was pressure-pressed at 200 C. for 3 minutes at a pressure of 4 MPa to prepare a sample in which the single fiber was embedded in the resin. The sample was further cut, to obtain a test piece with thickness 0.2 mm, width 5 mm and length 30 mm in which the single fiber was buried in the center. A total of five test pieces were further made by the same method.

(30) These five test pieces were subjected to a tensile test under conditions of a test length of 14 mm and a strain rate of 0.3 mm/min using a usual tensile test jig, and the average breaking fiber length (L) when fiber breakage no longer takes place was measured using a transmission type optical microscope. The interfacial shear strength () (MPa) by the fragmentation method was determined from the following formula.
=(f.Math.d)/2Lc,Lc=(4/3).Math.L

(31) Here, Lc is the critical fiber length, L is the average value of the final breaking length (m) f the fiber, of is the fiber's tensile strength (MPa), and d is the fiber diameter (m). (Reference: Osawa et al., Journal of the Society of Textile Science, Vol. 33, No. 1 (1977))

(32) f was obtained by the following method as the tensile strength distribution of the fiber follows the Weibull distribution. That is, single fibers were used, and the relational expression between the sample length and the average tensile strength was determined from the average tensile strength obtained at sample lengths of 5 mm, 25 mm and 50 mm by the least squares method, and the average tensile strength when the sample length was Lc was calculated.

(33) (7) Appearance Evaluation of Winding Molded Article

(34) The appearance of the winding molded article was visually evaluated. Evaluation items are resin squeezing out, fiber protruding, surface smoothness and surface gloss.

(35) (8) Method for Measuring Melting Point

(36) The melting point (Tm) of the polymer was measured by a differential scanning calorimeter (DSC) on a DSC 220C apparatus manufactured by Seiko Instruments Inc. Specifically, 7 to 12 mg of samples were sealed in an aluminum pan and heated from room temperature to 200 C. at 10 C./min. The sample was held at 200 C. for 5 minutes to completely melt all crystals and then cooled to 50 C. at 10 C./min. After 5 min at 50 C., the sample was heated a second time to 200 C. at 10 C./min. In this second heating test, the peak temperature was adopted as the melting point (Tm-II).

(37) Hereinafter, the materials used in Examples are shown.

(38) (Reinforcing Fiber (C))

(39) A carbon fiber bundle (manufactured by Mitsubishi Rayon Co., Ltd., trade name PYROFIL TR50S12L, number of filaments 24,000, strand strength 5000 MPa, strand elastic modulus 242 GPa) was immersed in acetone, ultrasonic waves were acted on this for 10 minutes, then, the carbon fiber bundle was lifted, and further washed three times with acetone and dried at room temperature for 8 hours to remove the adhered sizing agent before use.

Production Example 1: Production of Emulsion

(40) One hundred (100) parts by mass of a propylene-butene copolymer having a Shore D hardness of 52 and a weight average molecular weight measured by GPC of 350,000 as the propylene-based resin (A), 10 parts by mass of a maleic anhydride-modified propylene-based polymer (weight average molecular weight Mw 20,000, acid value 45 mg KOH/g, maleic anhydride content rate 4% by mass, melting point 140 C.) as the raw material of the propylene-based resin (B), and 3 parts by mass of potassium oleate as the surfactant were mixed. This mixture was fed at a rate of 3000 g/hr from a hopper of a twin-screw extruder (PCM-30, L/D=40, manufactured by Ikegai Tekko Co., Ltd.), and a 20% aqueous potassium hydroxide solution was continuously fed from a feed port provided in the vent of the extruder at a rate of 90 g/hour, and continuously extruded at a heating temperature of 210 C. The extruded resin mixture was cooled to 110 C. with a jacketed static mixer set at the mouth of the extruder and then poured into warm water at 80 C. to obtain an emulsion. The solid content concentration of the obtained emulsion was 45%.

(41) The above-described maleic anhydride-modified propylene-based resin is a modified resin obtained by mixing 96 parts by mass of a propylene-butene copolymer, 4 parts by mass of maleic anhydride, and 0.4 parts by mass of a polymerization initiator (manufactured by NOF Corp., trade name PERHEXA 25B), followed by modification at a heating temperature of 160 C. for 2 hours.

Production Example 2: Production of Emulsion

(42) An emulsion was produced in the same manner as described in Production Example 1 except that the propylene-butene copolymer was changed to a propylene-based resin containing a propylene unit, a butene unit and an ethylene unit and having a weight average molecular weight of 330,000 and a Shore A hardness of 75.

Production Example 3: Production of Emulsion

(43) An emulsion was produced in the same manner as described in Production Example 1 except that the propylene-butene copolymer was changed to a propylene-based resin containing a propylene unit, a butene unit and an ethylene unit and having a weight average molecular weight of 340,000 and a Shore A hardness of 84.

Production Example 4: Production of Emulsion

(44) An emulsion was produced in the same manner as described in Production Example 1 except that 80 parts by mass of a propylene-butene copolymer having a Shore D hardness of 52 and a weight average molecular weight measured by GPC of 350,000 as the propylene-based resin component (A-1) and 20 parts by mass of a maleic anhydride-modified propylene-based polymer (weight average molecular weight=100,000, acid value=11 mg KOH/g) as the propylene-based resin component (A-2) were used.

Production Example 5: Production of Emulsion

(45) To 100 parts by mass of a propylene-butene copolymer having a Shore D hardness of 52, a weight average molecular weight measured by GPC of 350,000 and a melting point of 80 C. as the propylene-based resin (A), 0.01 part by mass of maleic anhydride and 0.005 parts by mass of a polymerization initiator (manufactured by NOF Corp., trade name PERHEXA 25B) were added and after thorough mixing, they were reacted at an extrusion temperature of 230 C., a rotation speed of 200 rpm and an extrusion rate of 20 kg/hr using a twin-screw extruder (manufactured by Nippon Purakon Ltd., 30 mm extruder, L/D=42, same direction rotation, no vent). The resultant modified resin had a weight average molecular weight measured by GPC of 330,000, and the content rate of oxygen (group 16 element in the periodic table) calculated from the feeding ratio of the propylene-butene copolymer and maleic anhydride was 0.0049% by mass.

(46) One hundred (100) parts by mass of this propylene-butene copolymer, 10 parts by mass of a maleic anhydride-modified propylene-based polymer (weight average molecular weight Mw 20,000, acid value 45 mg KOH/g, maleic anhydride content rate 4% by mass, melting point 140 C.) as the raw material of the propylene-based resin (B), and 3 parts by mass of potassium oleate as the surfactant were mixed. This mixture was fed at a rate of 3000 g/hr from a hopper of a twin-screw extruder (PCM-30, L/D=40, manufactured by Ikegai Tekko Co., Ltd.), and a 20% aqueous dimethylethanolamine solution was continuously fed from a feed port provided in the vent of the extruder at a rate of 150 g/hour, and continuously extruded at a heating temperature of 210 C. The extruded resin mixture was cooled to 110 C. with a jacketed static mixer set at the mouth of the extruder and then poured into warm water at 80 C. to obtain an emulsion. The solid content concentration of the resultant emulsion was 45%.

(47) The above-described maleic anhydride-modified propylene-based resin used as the raw material of the propylene-based resin (B) is a modified resin obtained by mixing 96 parts by mass of a propylene-butene copolymer, 4 parts by mass of maleic anhydride, and 0.4 parts by mass of a polymerization initiator (manufactured by NOF Corp., trade name PERHEXA 25B), followed by modification at a heating temperature of 160 C. for 2 hours (oxygen content rate 1.96% by mass).

Comparative Production Example 1: Production of Emulsion

(48) An emulsion was produced in the same manner as described in Production Example 1 except that the propylene-butene copolymer was changed an olefin-based copolymer containing a propylene unit, a butene unit and an ethylene unit and having a weight average molecular weight of 100,000 in which the Shore A hardness was out of the measurement range.

Comparative Production Example 2: Production of Emulsion

(49) An emulsion was produced in the same manner as described in Production Example 1 except that a propylene-butene-ethylene copolymer having a weight average molecular weight measured by GPC of 120,000 and having no melting was used as the propylene-based resin (A).

Example 1-1

(50) The emulsion obtained in Production Example 1 was adhered to the above-described reinforcing fiber manufactured by Mitsubishi rayon using a roller impregnation method. Then, it was dried on-line at 130 C. for 2 minutes to remove low-boiling point components to obtain a reinforcing fiber bundle of the present invention. The adhesion amount of the emulsion was 0.87% by mass. The fuzzing resistance of the carbon fiber bundle was acceptable. The interfacial shear strength (IFSS) was measured using a mixture (weight ratio 95/5, Mw 300,000) of a commercially available unmodified polypropylene resin (manufactured by Prime Polymer Co., Ltd., trade name Prime Polypro J106 MG) and a modified polypropylene (melt flow rate measured in accordance with ASTM D1238 at 230 C. and a load of 2.16 kg: 9.1 g/10 min) grafted with 0.5% by mass of maleic anhydride, as the matrix resin (M). IFSS was 19.7 MPa. Then, a carbon fiber-reinforced thermoplastic resin molded article of the present invention was produced (fiber volume fraction Vf 0.4) using 57 parts of this reinforcing fiber and 43 parts of a mixture (weight ratio 95/5, Mw 300,000) of a commercially available unmodified polypropylene resin (manufactured by Prime Polymer Co., Ltd., trade name Prime Polypro J106 MG) and a modified polypropylene (melt flow rate measured in accordance with ASTM D1238 at 230 C.: 9.1 g/10 min) grafted with 0.5% by mass of maleic anhydride, as the matrix resin (M).

Example 1-2

(51) A reinforcing fiber bundle of the present invention was obtained in the same manner as in Example 1-1 except that the emulsion obtained in Production Example 2 was used. The adhesion amount of the emulsion was 1.27% by mass. The fuzzing resistance of the carbon fiber bundle was acceptable. IFSS was 18.7 Mpa.

Example 1-3

(52) A reinforcing fiber bundle of the present invention was obtained in the same manner as in Example 1-1 except that the emulsion obtained in Production Example 3 was used. The adhesion amount of the emulsion was 1.7% by mass. The fuzzing resistance of the carbon fiber bundle was acceptable. IFSS was 17.2 MPa.

Comparative Example 1-1

(53) A reinforcing fiber bundle was obtained in the same manner as in Example 1-1 except that the emulsion obtained in Comparative Production Example 1 was used. The adhesion amount of the emulsion was 1.6% by mass. The fuzzing resistance of the carbon fiber bundle was rejected. IFSS was 19.8 MPa.

Comparative Example 1-2

(54) A carbon fiber bundle (manufactured by Mitsubishi Rayon Co., Ltd., trade name PYROFIL TR50S12L, number of filaments 12,000, strand strength 5000 MPa, strand elastic modulus 242 GPa) was used as it is. The fuzzing resistance was passed. The interfacial shear strength (IFSS) was measured using a mixture (weight ratio 95/5, Mw 300,000) of a commercially available unmodified polypropylene resin (manufactured by Prime Polymer Co., Ltd., trade name Prime Polypro J106 MG) and a modified polypropylene (melt flow rate measured in accordance with ASTM D1238 at 230 C.: 9.1 g/10 min) grafted with 0.5% by mass of maleic anhydride, as the matrix resin (M). IFSS was 11.0 MPa.

(55) As can be seen from the above Examples 1-1 to 1-3 and Comparative Examples 1-1 to 1-2, the reinforcing fiber bundle of the present invention has excellent performance in which few fuzz and high interfacial shear strength are compatible. Therefore, a propylene-based resin composition containing the reinforcing fiber bundle is also expected to have excellent strength and appearance.

Example 2-1

(56) In this example, a unidirectional material (UD material), which is a molded article containing fibers in which opened fiber bundles are aligned in one direction, is produced. Specifically, as shown in FIG. 1 of Japanese Patent No. 4522498, after the opened fiber bundles are aligned, brought into contacted with the molten matrix resin coated on the impregnation roll (5), and pulled, to obtain a unidirectional carbon fiber-reinforced thermoplastic resin molded article. The temperature of the extruder and T die was 260 C., and the temperature of the impregnation roll was 260 C.

(57) In this example, the emulsion produced in Production Example 1 was allowed to adhere to the above-described reinforcing fiber manufactured by Mitsubishi Rayon Co., Ltd. using a roller impregnation method. Then, it was dried on-line at 130 C. for 2 minutes to remove low-boiling components, to obtain a reinforcing fiber bundle of the present invention. The adhesion amount of the emulsion was 0.87% by mass, and the fuzzing resistance of the carbon fiber bundle was acceptable.

(58) Next, a unidirectional carbon fiber-reinforced thermoplastic resin molded article of the present invention was produced using 51 parts of this reinforcing fiber and 49 parts of polyamide 6 (trade name UBE NYLON 1015B, melting point 220 C., density 1.14 g/cc, manufactured by Ube Industries, Ltd.) as the matrix resin (M).

Example 2-2

(59) A unidirectional carbon fiber-reinforced thermoplastic resin molded article of the present invention was produced in the same manner as in Example 2-1 except that 54 parts by mass of a reinforcing fiber and 46 parts by mass of polyamide 12 (trade name UBESTA 3014U, melting point 180 C., density 1.02 g/cc, manufactured by Ube Industries, Ltd.) as the matrix resin (M) were used.

Example 2-3

(60) A carbon fiber-reinforced thermoplastic resin molded article of the present invention was produced in the same manner as in Example 2-1 except that the emulsion obtained in Production Example 4 was used as the sizing agent.

Example 2-4

(61) A carbon fiber-reinforced thermoplastic resin molded article of the present invention was produced in the same manner as in Example 2-2 except that the emulsion obtained in Production Example 4 was used as the sizing agent.

Comparative Example 2-1

(62) An epoxy-based sizing agent (2,2-bis(4-glycidyloxyphenyl)propane manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the sizing agent. The 1% aqueous solution thereof was adhered to the above-described reinforcing fiber manufactured by Mitsubishi rayon using a roller impregnation method. Next, it was dried on-line at 130 C. for 2 minutes to obtain a reinforcing fiber bundle. The adhesion amount was 0.85%. A carbon fiber-reinforced thermoplastic resin molded article was produced in the same manner as in Example 2-1 except that this reinforcing fiber bundle was used.

Comparative Example 2-2

(63) An epoxy-based sizing agent (2,2-bis(4-glycidyloxyphenyl)propane manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the sizing agent. The 1% aqueous solution thereof was adhered to the above-described reinforcing fiber manufactured by Mitsubishi rayon using a roller impregnation method. Next, it was dried on-line at 130 C. for 2 minutes to obtain a reinforcing fiber bundle. The adhesion amount was 0.85%. A carbon fiber-reinforced thermoplastic resin molded article was produced in the same manner as in Example 2-2 except that this reinforcing fiber bundle was used.

(64) The following evaluations were made on each molded article above. The results are shown in Table 1.

(65) [Fuzz]

(66) The number of fluffs caused by friction was measured in the same manner as the method described in examples of Japanese Patent No. 5584977, and evaluated according to the following criteria.

(67) A: Number of fluffs caused by friction is 0 to 10/m

(68) B Number of fluffs caused by friction is 11 to 50/m

(69) X: Number of fluffs caused by friction is 51/m or more

(70) [Cutting of Fiber (Around Surface)]

(71) The presence or absence of fiber bundle cutting in the vicinity of the guide roll surface of the fiber at the time of producing a unidirectional material was visually confirmed and evaluated according to the following criteria.

(72) A: No breakage of fiber occurred

(73) X: Friction of fiber occurred

(74) [Winding of Fiber on Roll]

(75) The presence or absence of winding of fiber on an impregnation roll at the time of producing a unidirectional material was confirmed and evaluated according to the following criteria.

(76) A: Winding of fiber on roll did not occur

(77) X: Winding of fiber on roll occurred

(78) [Peel Off of Resin]

(79) The presence or absence of peel off of a resin in a take-off device at the time of producing a unidirectional material was visually confirmed and evaluated according to the following criteria.

(80) A: Peel off of resin did not occur

(81) B: Peel off of resin slightly occurred, but there was no problem in production

(82) X: Peel off of resin remarkably occurred

(83) [Impregnating Property]

(84) The impregnating property of a resin at the time of producing a unidirectional material was visually confirmed and evaluated according to the following criteria.

(85) A: Resin was sufficiently impregnated

(86) B: Impregnation of resin was somewhat inferior, but there was no problem in production

(87) X: Impregnation of resin was insufficient

(88) [Mechanical Property]

(89) (Preparation of Unidirectional Laminate)

(90) Further, eight sheets of the unidirectional material sheets were laminated in the direction of 0 and this was placed in a press apparatus (manufactured by Shinto Metal Industry Co., Ltd., apparatus name: NSF-37HHC) equipped with a flat metal mold. It was pressurized and compressed for 3 minutes at 5 MPa at 240 C. in Examples 1 and 3 and Comparative Example 1 and at 220 C. in Examples 2 and 4 and Comparative Example 2, and thereafter, cooled immediately while keeping the pressurized state, to obtain a unidirectional laminate of 1.0 mm thickness.

(91) (Measurement of Mechanical Property)

(92) The obtained unidirectional laminate was cut out to prepare four test pieces (250 mm15 mm), a tensile test was conducted at a speed of 2 mm/min using a tensile test machine (manufactured by Zwick, apparatus name Z100), and the elastic modulus and the breaking strength were measured (in accordance with ASTM D 3039), and the average value of four test pieces was taken. The interlaminar shear stress (ILSS) was measured (in compliance with ASTM D 2344) using a short span bending test apparatus (manufactured by Shimadzu Corp., apparatus name Shimadzu Autograph AG-5KNX).

(93) [Vf (Fiber Volume Fraction)]

(94) It was decided according to JIS K 7075 standard.

(95) TABLE-US-00001 TABLE 1 Ex. Ex. Ex. Ex. Comp. Comp. 2-1 2-2 2-3 2-4 Ex. 2-1 Ex. 2-2 Sizing Agent Pro. Pro. Pro. Pro. Epoxy Epoxy Ex. 1 Ex. 1 Ex. 4 Ex. 4 Matrix Resin PA6 PA12 PA6 PA12 PA6 PA12 Fuzz A A B B B B to A to A Cutting of A A A A X X Fiber (around surface) Winding of A A A A X X Fiber on Roll Peel off of B B A A X X Resin Impregnating B B A A X X Pproperty Mechanical property Vf (fiber 38 37 37 39 36 38 volume frac- tion) % Tensile Elastic 92 88 89 95 85 91 Modulus (GPa) Tensile 1056 1084 1124 1241 652 757 strength (MPa) ILSS (MPa) 39.6 46.3 42.6 47.1 36.2 38.4

(96) As can be seen from the above Examples 2-1 to 2-4 and Comparative Examples to 2-1 to 2-2, the reinforcing fiber bundle of the present invention has excellent performance in which few fuzz and high interfacial shear strength are compatible. Therefore, it is expected that the polyamide resin composition containing the reinforcing fiber bundle also has excellent strength and appearance. In addition, since the polyamide resin (E) is used as the matrix resin (M), it is also expected to improve adhesion to a metal.

Example 3-1

(97) The emulsion produced in Production Example 1 was adhered to the above-described reinforcing fiber manufactured by Mitsubishi Rayon Co. Ltd. using a roller impregnation method. Then, it was dried on-line at 130 C. for 2 minutes to remove low-boiling point components to obtain a reinforcing fiber bundle of the present invention. The adhesion amount of the emulsion was 0.87% by mass. The fuzzing resistance of the carbon fiber bundle was acceptable. Next, a resin composition containing 57 parts of this reinforcing fiber and 43 parts by mass of a commercially available unmodified propylene resin (trade name Prime Polypro J106MG, melting point 160 C., manufactured by Prime Polymer Co., Ltd.) and a modified polypropylene (melt flow rate measured according to ASTM D 1238 at 190 C. and at a load of 2.16 kg: 9.1 g/10 min, melting point: 155 C.) grafted with 0.5% by mass of maleic anhydride as the matrix resin (M) was prepared, and a sheet having an average thickness of 150 m was prepared by a conventional method. The mass ratio of the above-described J106MG to the modified polypropylene was 90/10 (corresponding to a weight average molecular weight of 330,000) (melting point of resin is 160 C., content rate of maleic anhydride to the whole resin composition is 0.023% by mass) (fiber volume fraction Vf 0.4).

(98) Using a slitter, this was cut into a 12 mm width tape, which was wound on a mandrel having an inner diameter of 95 mm, to mold a pipe, by using a STWH INB type winding head manufactured by AFPT Co., Ltd. which closed-loop-controls diode laser with a power output of 3 kW and having a wavelength of 960 to 1070 nm, the head being installed in a robot. In winding, lamination is performed alternately at +20 and 20, to obtain a two-layered winding pipe. Further, one layer of 80 angle tape was laminated on the surface under the following molding conditions, to obtain a winding pipe leaving a 100 mm length unfused tape.

(99) Condition 1: laser molding temperature 180 C., winding speed 10 m/min

(100) Condition 2: laser molding temperature 180 C., winding speed 30 m/min

(101) Condition 3: laser molding temperature 200 C., winding speed 60 m/min

(102) Condition 4: laser molding temperature 200 C., winding speed 90 m/min

(103) The appearance of the winding molded article was that the resin did not squeeze out, the fibers did not protrude, the surface smoothness was good, and the surface gloss was good.

(104) A tape of this winding molded article was forcibly peeled using a wedge-shaped jig having a thickness 1.4 mm and a tip angle of 30, and the peeled surface was observed by an electron microscope manufactured by JEOL Ltd., as a result, there was no peeling of the matrix resin part (peeling of the interface between the reinforcing fiber and the resin and partial breakage of the reinforcing fiber were observed). The appearance of the winding molded article was that there was no squeezing out of the resin, the fiber did not protrude, the surface smoothness was good, and the surface gloss was also good.

(105) A tape of this winding molded article was subjected to a peeling test in the following manner. A method improved so that a thermoplastic composite can be reliably measured by combining a drum peel test (ASTM 1781) with a wedge peel test (a method of peeling off the tape while the wedge is in contact with the peeling point, ISO11343) was used. The peeling strength (N/m) was measured by applying a wedge-shaped jig having a thickness of 1.4 mm and a tip angle of 30 to the peeling surface, pulling the tape at a speed of 2 mm/s, and normalizing the average peel force with the width of the peeling surface. The results of peeling strength were as follows.

(106) Condition 1: peeling strength 5700 N/m

(107) Condition 2: peeling strength 6900 N/m

(108) Condition 3: peeling strength 3500 N/m

(109) Condition 4: peeling strength 5500 N/m

Comparative Example 3-1

(110) A winding pipe was obtained in the same manner as in Example 3-1 except that the emulsion obtained in Comparative Production Example 2 was used as the sizing agent. The content rate of the structural unit containing the carboxylic acid group was 0.023% by mass.

(111) The outer appearance of the winding molded article was that the squeezing out of the resin and the protrusion of the fiber were observed, and both the surface smoothness and the surface gloss were not sufficient (level inferior to Examples). The obtained winding pipe was subjected to a peeling test in the same manner as in Example 1, and the peeling strength results shown below were obtained.

(112) Condition 1: peeling strength 1600 N/m

(113) Condition 2: peeling strength 2100 N/m

(114) Condition 3: peeling strength 800 N/m

(115) Condition 4: peeling strength 700 N/m

(116) As can be seen from the above Example 3-1 and Comparative Example 3-1, the tape winding molded article of the present invention has excellent appearance and surface characteristics, and a property that peeling hardly occurs.

Example 4-1

(117) The emulsion obtained in Production Example 5 was adhered to the above-described reinforcing fiber manufactured by Mitsubishi Rayon Co. Ltd. using a roller impregnation method. Then, it was dried on-line at 130 C. for 2 minutes to remove low-boiling point components, to obtain a reinforcing fiber bundle of the present invention. The adhesion amount of the emulsion was 0.87% by mass. The fuzzing resistance of the carbon fiber bundle was acceptable.

(118) Next, a resin composition containing 57 parts of this reinforcing fiber and 43 parts by mass of a commercially available unmodified propylene resin (trade name Prime Polypro J106MG, melting point 160 C., manufactured by Prime Polymer Co., Ltd.) and a modified polypropylene (melt flow rate measured according to ASTM D 1238 at 190 C. and at a load of 2.16 kg: 9.1 g/10 min, melting point: 155 C.) grafted with 0.5% by mass of maleic anhydride as the matrix resin (M) was prepared, and a sheet having an average thickness of 150 m was prepared by a conventional method. The mass ratio of the above-described J106MG to the modified polypropylene was 85/15 (corresponding to a weight average molecular weight of 320,000) (melting point of resin is 160 C., content rate of maleic anhydride to the whole resin composition is 0.034% by mass) (fiber volume fraction Vf 0.4).

(119) Using a slitter, this was cut into a 12 mm width tape, which was wound on a mandrel having an inner diameter of 95 mm, to mold a pipe, by using a STWH INB type winding head manufactured by AFPT Co., Ltd. which closed-loop-controls diode laser with a power output of 3 kW and having a wavelength of 960 to 1070 nm, the head being installed in a robot. In winding, lamination is performed alternately at +20 and 20, to obtain a two-layered winding pipe. Further, one layer of 80 angle tape was laminated on the surface under the following molding conditions, to obtain a winding pipe leaving a 100 mm length unfused tape.

(120) Condition 1: laser molding temperature 180 C., winding speed 10 m/min

(121) Condition 2: laser molding temperature 180 C., winding speed 30 m/min

(122) Condition 3: laser molding temperature 200 C., winding speed 60 m/min

(123) Condition 4: laser molding temperature 200 C., winding speed 90 m/min

(124) The appearance of the winding molded article was that the resin did not squeeze out, the fibers did not protrude, and the surface smoothness was also good. Further, the surface gloss was good.

(125) A tape of this winding molded article was forcibly peeled using a wedge-shaped jig having a thickness 1.4 mm and a tip angle of 30, and the peeled surface was observed by an electron microscope manufactured by JEOL Ltd., as a result, there was no peeling of the matrix resin part (peeling of the interface between the reinforcing fiber and the resin and partial breakage of the reinforcing fiber were observed).

(126) A tape of the above-described winding molded article was subjected to a peeling test in the following manner. A method improved so that a thermoplastic composite can be reliably measured by combining a drum peel test (ASTM 1781) with a wedge peel test (a method of peeling off the tape while the wedge is in contact with the peeling point, ISO 11343) was used. The peeling strength (N/m) was measured by applying a wedge-shaped jig having a thickness of 1.4 mm and a tip angle of 30 to the peeling surface, pulling the tape at a speed of 2 mm/s, and normalizing the average peel force with the width of the peeling surface. The results of peeling strength were as follows.

(127) Condition 1: peeling strength 7200 N/m

(128) Condition 2: peeling strength 6800 N/m

(129) Condition 3: peeling strength 6500 N/m

(130) Condition 4: peeling strength 5600 N/m

(131) As can be seen from the above Example 4-1, the embodiment of the present invention using the propylene-based resin (A-1) having a high molecular weight and having the functional group described above has good surface condition and good appearance, and additionally, is excellent particularly in peeling strength.

INDUSTRIAL APPLICABILITY

(132) The reinforcing fiber bundle of the present invention is excellent in handling properties, manifests excellent adhesion to the matrix resin (M) and has excellent surface characteristics and peeling strength, therefore, the reinforcing fiber bundle can provide a fiber-reinforced thermoplastic resin molded article excellent in handling properties and having high mechanical property, and can be developed in various applications. Particularly, the reinforcing fiber bundle is suitable for automobile parts, electric/electronic parts, and home and office electric products parts. Further, since the molding material of the present invention is also excellent in adhesion to metals, it is also useful for various applications in which it is necessary to bond a molding material to a metal.