JPH06240049A - Carbon-fiber-reinforced thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To improve the dimensional accuracy, tensile strength, tensile modulus, bending strength, impact strength, etc., of a molded article made of the subject compsn. by compounding a thermoplastic resin with a carbon fiber having a specified diameter and a carbon black each in a specified amt. CONSTITUTION:This resin compsn. is prepd. by compounding a thermoplastic resin with 3-30wt.% carbon fiber having a diameter of 1-6mum and 0-20 wt.% carbon black. Polyacrylonitrile-and pitch-derived carbon fibers are suitable, and they may be precoated with a sizing a coupling agent (e.g. a vinylalkylsilane) to improve the processibility or adhesion to the resin. As the carbon b1ack, are used a furnace black, acetylene black, etc. A polycarbonate resin, a polyacetal resin, a styrenic resin, etc., are used as the resin. Thus obtd. compsn. is useful for producing automotive parts, electronic parts, etc.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a carbon fiber reinforced heat having excellent dimensional accuracy, tensile strength, tensile elastic modulus, bending strength, bending elastic modulus, impact strength, heat resistance, conductivity, and appearance of molded products. Regarding the plastic resin composition, it is mainly a molded product excellent in high mechanical strength, dimensional accuracy, conductivity and appearance, and can be used in a wide range of fields such as electric / electronic parts, OA equipment parts, automobile parts and sundries.

[0002]

2. Description of the Related Art Thermoplastic resins are characterized by excellent mechanical properties, thermal properties, electrical properties, dimensional accuracy, a high degree of freedom in the shape of molded products, and easy and reproducible molding. So it is used in a wide range of applications. Furthermore, for the purpose of improving mechanical properties, thermal properties, electrical properties, and dimensional accuracy, a method of adding a mineral reinforcing agent such as glass fiber, carbon fiber, talc, mica, and needle-shaped titanium oxide has been proposed. It's When such a mineral reinforcement is added to the thermoplastic resin, the mineral reinforcement is exposed on the surface of the molded article,
There is a problem that the appearance of the molded product is significantly impaired. Regarding the addition of carbon fibers, the diameter of carbon fibers used for practically molded products is generally 7 μm or more, and a resin composition in which carbon fibers having a diameter of 7 μm or more are melt-kneaded with a thermoplastic resin is known. For example, Japanese Examined Patent Publication No. 4-48825 discloses adding carbon fiber having a diameter of 100 μm to polyphenylene ether. However, in such a resin composition to which carbon fibers having a diameter of 7 μm or more are added, there is a problem that the carbon fibers are very likely to be exposed on the surface of the molded product and the appearance is significantly impaired.

Regarding the addition of glass fiber, in order to improve the appearance of the molded product of glass fiber reinforced PC, JP-A-60-4 was used.
No. 550, a method of adding low-molecular weight PC is also proposed, and the effect of adding low-molecular weight PC to carbon fiber is recognized to some extent, but it is not always satisfactory.

[0004]

SUMMARY OF THE INVENTION The present inventors have solved the above-mentioned problems by solving the above-mentioned problems and mechanical properties such as dimensional accuracy, tensile strength, tensile elastic modulus, bending strength, bending elastic modulus and impact strength. For the purpose of providing a carbon fiber reinforced thermoplastic resin composition excellent in heat resistance, conductivity, and appearance and smoothness of a molded product, earnest research was conducted to complete the present invention.

[0005]

According to the present invention, a carbon fiber having a diameter of 1 to 6 .mu.m, which is thinner than that of the prior art, is 3 to 30 w.
Dimensional accuracy, tensile strength, tensile modulus, flexural strength, flexural modulus, impact strength, heat resistance, conductivity, appearance and smoothness of molded products, containing t% and 0 to 20 wt% of carbon black. It is a carbon fiber reinforced thermoplastic resin composition having excellent properties.

The carbon fiber used in the present invention may be either pitch-based or PAN-based carbon fiber. The diameter of carbon fiber is "reinforced plastics, Vol.34, N
o. 3-6, P89-93 ".
It is possible to control. As long as the carbon fiber has a diameter in this range, the carbon fiber can be appropriately selected depending on the purpose, such as roving type, chopped strand, milled fiber, and powder type.

The carbon fiber used in the present invention may be coated with a known sizing agent or coupling agent in order to improve workability and adhesion between the carbon fiber and the thermoplastic resin. As the carbon fiber coupling agent, known ones such as vinylalkylsilane, methacryloalkylsilane, epoxyalkylsilane, aminoalkylsilane, mercaptoalkylsilane, and chloroalkylsilane can be used. As the sizing agent, epoxy type, polyester type, urethane type, polystyrene type and the like can be used.

The carbon black used in the present invention is
Powdered or granular carbon such as fannes black or acetylene black is used. For example, American C
Vulcan XC72 manufactured by ABOT, Asahi HS-500 manufactured by Asahi Carbon Co., Ltd., Ketjen Black EC manufactured by Akzo of the Netherlands, SEAS-116 manufactured by Tokai Carbon Co., Ltd. and the like can be used.

The thermoplastic resin used in the present invention is usually commercially available PMMA, styrene resin, PPE, P
It is at least one thermoplastic resin selected from BT, PET, POM, PC, polyamide, polysulfone, polyarylene polyether polysulfone, and polyphenylene sulfide. The polyamides include aliphatic nylons such as 4 nylon, 6 nylon, 66 nylon, 11 nylon and 12 nylon, aromatic nylons such as polyhexadiamine terephthalamide, polyhexamethylene diamine isophthalamide and xylene group-containing polyamide. And so on. Examples of the styrene resin include polystyrene, rubber-modified polystyrene, ABS, AS and AA.
S, AMBS, AES, styrene-maleic acid copolymer, etc. When two or more types of thermoplastic resins are mixed and used, a known compatibilizer may be used.

The resin composition of the present invention has a fiber diameter of 1
3 to 30 wt% of carbon fiber of ˜6 μm and 0 to 20 wt% of carbon black are contained. Carbon fibers having a diameter smaller than 1 μm are difficult to manufacture by themselves. Diameter is 6
It is not preferable to add carbon fibers larger than μm because the appearance and smoothness of the molded product will be poor. If the carbon fiber addition rate is lower than 3 wt%, the mechanical strength and conductivity are not sufficiently improved. Addition rate of carbon fiber is 30w
If it exceeds t%, the appearance and smoothness of the molded product will be poor, and further the abrasion of the screw and cylinder of the extruder or injection molding machine will be severe, which is not preferable. If the addition rate of carbon black exceeds 20 wt%, the melt viscosity of the resin composition becomes high, making it difficult to mold thin-walled molded products and large-sized molded products, and further, the appearance and smoothness of the molded products become poor, which is not preferable. .

The resin composition of the present invention has a low molecular weight PC, a low molecular weight PPE, a low molecular weight PBT, a low molecular weight PET, a low molecular weight PS and a low molecular weight A in order to further improve the appearance.
A so-called oligomer such as S may be added in the range of 30 wt% or less.

If necessary, the following elastomer may be added to the resin composition of the present invention. That is, a block copolymer consisting of polystyrene and hydrogenated polyisoprene (for example, Septon manufactured by Kuraray Co., Ltd.), hydrogenated SEBS (for example, Kraton G manufactured by Shell Chemical Co., Ltd.), an ethylene-α-olefin copolymer (for example, Mitsui Oil Co., Ltd.). Chemical Co., Ltd. Tuffmer) and propylene-α-olefin copolymer, acrylic rubber, SBR,
Known elastomers such as thermoplastic polyester elastomers and polyester / polyether coelastomers can be used.

In the present invention, glass fibers having a diameter of 6 μm or less, glass flakes having an average diameter of 50 μm or less, glass beads having a diameter of 30 μm or less, and an average length of 5 are used within a range not impairing the appearance.
Fillers such as mica of 0 μm or less, acicular titanium oxide, potassium titanate whiskers, and talc may be added.

In the resin composition of the present invention, known phosphorus compounds such as triphenyl phosphate, tricresyl phosphate and polycondensates thereof, halogen compounds are used as flame retardants, and antimony trioxide and tetraoxide are used. Flame retardant aids such as antimony can also be added. Antioxidants, heat stabilizers, UV absorbers, plasticizers, lubricants, release agents and the like can also be added depending on the required performance.

The resin composition of the present invention can be produced by the equipment and method generally used for producing a thermoplastic resin composition. For example, it is also possible to produce pellets for molding by mixing the components constituting the carbon fiber reinforced thermoplastic resin composition all at once with a mixer such as a tumbler or separately and kneading them using a uniaxial or biaxial extruder. Is.

[0016]

【Example】

Examples 1 to 5 and Comparative Examples 1 to 5 The present invention will be specifically described with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto. The molding method and test method for the test pieces in the examples and comparative examples are as follows, and the addition ratio of the components (all units below are wt%)
The test results are shown in Tables 1 and 2.

(1) Main raw materials Polycarbonate resin: Mitsubishi Gas Chemical Co., Ltd. Iupilon S2000 (abbreviated as PC) Polyacetal resin: Mitsubishi Gas Chemical Co., Ltd. Iupital F20-02 (abbreviated as POM) PPE resin: Mitsubishi Gas Chemical Yupiace AH40 manufactured by Co., Ltd.
(Abbreviated as PPE) PAN-based carbon fiber: Bethfight manufactured by Toho Rayon Co., Ltd. and others (abbreviated as CF) Carbon black: Ketjenblack EC made by Akzo in the Netherlands (abbreviated as EC)

(2) Molding conditions for test piece After mixing the components in the ratios shown in Table 1, the screw diameter 30
A pellet is manufactured by melt-kneading with a mm twin-screw extruder. After drying the pellets at 100 ° C. for 5 hours, the mold temperature was 11 by using an SG125 injection molding machine manufactured by Sumitomo Heavy Industries, Ltd.
0 ℃, cylinder set temperature 220 ℃ (POM is 3
00 ° C (for PC and PPE), injection pressure 100MPa
Mold the test piece with.

(3) Tensile strength (abbreviated as TS, unit MP
a) Using ASTM-D638 standard 3.2 mm tensile test piece,
Five tests of one type were performed under the conditions of 23 ° C. and a pulling speed of 5 mm / min, and the average value of the five tests is shown.

(4) Flexural strength and flexural modulus (BS and BM
Abbreviated as "MPa and GPa") A strip type test piece of 3.2 x 12.7 x 63.5 mm was used, and 5 pieces of each type were tested under the conditions of 23 ° C and a bending speed of 5 mm / min, and an average of 5 pieces was used. Indicated by value.

(5) Deflection temperature under load (abbreviated as DTUL, unit: ° C) According to ASTM-D648, 3 pieces were measured at a load of 1.82 MPa and the average value was shown.

(6) Surface resistivity (abbreviated as SR and unit is Ω) 10 at 6 points on a disc having a diameter of 100 mm and a thickness of 3.2 mm.
Apply silver paint at 6 mm intervals at 6 mm intervals at 23 ° C for 5
It was dried in a 5% RH chamber for 48 hours or more to prepare a silver electrode on a disc. The resistance between the silver electrodes on the disk was measured with an Advantech Digital Multimeter IR-6853. The measurement was carried out at 7 points / sheet, and the average value of 5 measurements excluding the maximum and minimum values was shown.

(7) Appearance of molded product A disc having a diameter of 100 mm and a thickness of 3.2 mm is visually observed, and a molded product having a good appearance is A, an ordinary molded product is B, and carbon fiber or carbon black is the surface of the molded product. A molded product that is exposed to the outside and has a bad appearance is judged as C.

[0024]

The carbon fiber reinforced thermoplastic resin composition of the present invention has dimensional accuracy, tensile strength, tensile modulus, flexural strength, flexural modulus, impact strength, heat resistance, conductivity, and appearance of molded products. Since it has excellent smoothness and smoothness, it can be used in a wide range of fields such as electric / electronic parts, OA equipment parts, automobile parts and sundries.

Table 1 Example No. 1 2 3 4 5 PC (parts by weight) 90 80 0 0 0 POM (parts by weight) 0 0 80 0 0 PPE (parts by weight) 0 0 0 88 92 CF diameter (μm) 4 4 3 3 2 CF (parts by weight) 10 20 20 12 5 EC (parts by weight) 0 0 0 0 3 TS 130 130 160 160 130 100 BS 200 240 240 300 170 130 BM 7 12 17 17 10 6 DTUL 148 149 146 106 136 132 ⁵ 10 ² 10 ⁴ 10 ² 10 ⁴ Appearance A B A A A

Table 2 Table 2 Comparative Example No 1 2 3 4 5 PC (parts by weight) 90 80 0 0 0 POM (parts by weight) 0 0 80 0 0 PPE (parts by weight) 0 0 0 88 92 CF diameter (μm) 12 8 12 8 12 CF (weight part) 10 20 20 12 5 EC (weight part) 0 0 0 0 3 TS 110 110 140 130 110 85 BS 180 220 220 260 150 110 BM 6 11 14 9 4.5 DTUL 146 147 146 135 135 SR ⁶ 10 ³ 10 ⁵ 10 ³ 10 ⁵ Appearance C C C C C

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C08L 71/12 LQP 9167-4J 101/00

Claims (3)

[Claims] 1. A thermoplastic resin having a fiber diameter of 1 to 6 .mu.m.
m carbon fiber 3 to 30 wt% and carbon black 0 to 2
A thermoplastic resin composition containing 0 wt%. 2. The thermoplastic resin composition according to claim 1, wherein the carbon fibers are one or more selected from acrylonitrile-based carbon fibers and pitch-based carbon fibers. 3. The thermoplastic resin is PMMA, styrenic resin, PPE, PBT, PET, POM, PC, 4 nylon, 6 nylon, 66 nylon, 11 nylon, 12 nylon, polyhexadiamine terephthalate, etc. Amide, polyhexamethylenediamineisophthalic acid amide, polyhexadiamineterephthalamide, polyhexamethylenediamineisophthalic acid amide, aromatic nylon such as polyamide containing xylene group, polysulfone, polyarylene polyether polysulfone, polyphenylene sulfide The thermoplastic resin composition according to claim 1, which is one or more kinds.