JPS62275133A - Carbon fiber-reinforced thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in impact strength, adhesion of carbon fiber to thermoplastic resin and capability of binding fibers, by mixing a thermoplastic resin with a carbon fiber coated with a specified amount of a polyurethane resin. CONSTITUTION:A polyacrylic, rayon, pitch, carbonaceous or graphite carbon fiber (a) whose surface is treated preferably by oxidation is coated with 0.3-10wt% wholly thermoplastic linear polyurethane resin (b) obtained by reacting an isocyanate with a diol at an NCO to OH ratio in the range of 0.95-1.0 to obtain a polyurethane resin-coated carbon fiber (b). 97-40wt% thermoplastic resin (A) selected from among a polycarbonate resin, a polyamide resin and a thermoplastic saturated polyester resin is mixed with 3-60wt% component B.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention The present invention relates to a carbon fiber-reinforced thermoplastic resin composition that can be used for composite materials.
A thermoplastic resin composition that improves the mechanical properties, especially the impact strength, of a carbon 11!1a reinforced resin with a thermoplastic resin as a matrix, as well as improves the cohesiveness of fibers and improves the workability when mixing with the resin. It is about providing.

In recent years, high-performance engineering resin materials made by reinforcing thermoplastic resins with carbon fibers have attracted attention, and the demand for them is rapidly increasing. However, hydrocarbon fibers do not have active groups on their surfaces and are essentially inert, and have poor adhesion to thermoplastic resins. Although the mechanical properties are improved compared to the above, the degree of improvement is insufficient and it cannot be said that the properties of carbon am are fully utilized effectively.

Poor adhesion between carbon fibers and thermoplastic resins has a significant negative impact, particularly on the impact strength of the reinforced resins.

In order to mix the hydrocarbon fiber and the thermoplastic resin, it is common to melt and knead the fibers cut into suitable sizes, for example, 10 to 3II11), together with resin pellets or resin powder in an extruder. On this occasion! If the IM is not highly cohesive, the fibers will spread out due to the frictional force with the resin, become fluffy, float up in the extruder hopper, and only the resin will be supplied, resulting in a uniform distribution. It becomes difficult to obtain the resin composition regularly.

In order to avoid such difficulties, it is of course necessary to impart high cohesiveness to the fibers, and from the standpoint of preventing fiber opening, it is conceivable to use so-called milled fibers with a fiber length of 11 II g or less.

In order to improve the cohesiveness of the fibers, carbon fibers are coated with the same thermoplastic resin as the matrix resin, and in this case, the matrix resin is generally used after being dissolved in a solvent. In this case, solvents that degrade the environment during the treatment process are used, such as formic acid, phenol, etc. for polyamide resin, or chlorinated solvents for polycarbonate, polysulfone, and polyethersulfone resins. In addition, few thermoplastic resins are soluble in harmless solvents, and considering these factors, it is not preferable to use solvents to improve convergence. In addition, in order to prevent easy opening, the above-mentioned method of converting carbon fibers into milled fibers with a diameter of 11'III or less is such that the milled fibers are further converted into 4JAN in the screw when mixed, and the fiber length in the final molded product is reduced. is 0.
Since it is less than 1 mm, it does not contribute to improving various properties of the molded product, and is therefore not suitable for the purpose of obtaining a molded product with high strength and high elasticity.

Carbon mM is generally used in composite materials with epoxy resin as the matrix resin, in which case the fibers are sized with uncured epoxy resin, cut as is, and used as reinforcement for thermoplastic resins. When carbon fibers sized with such uncured epoxy resin come into contact with resin heated for drying in the hopper, the epoxy resin softens and the fibers tend to open, making steady operation difficult. Often.

As a result of various studies aimed at improving these problems, the inventors of the present invention found that by coating carbon fibers with a specific amount of polyurethane resin, the adhesiveness between carbon fibers and thermoplastic resin was increased and molded products were formed. The inventors have discovered that it is possible to improve the properties and further improve the cohesiveness of the fibers, thereby improving the workability when mixing the fibers and the resin, leading to the present invention.

Specifically, the present invention provides a carbon fiber-reinforced thermoplastic resin composition comprising 3-60% by weight of carbon fibers coated with 0.3-10% by weight of polyurethane resin and 97-40% by weight of thermoplastic resin. It is. and thermoplastic rMIF
In the resin composition, W is particularly selected from a polycarbonate resin, a polyamide resin, or a thermoplastic saturated polyester resin.

The coated carbon IIN in the present invention has excellent cohesiveness, so it can be smoothly fed from the hopper of an extruder when mixed with a resin to give a uniform resin composition, and is particularly useful for polycarbonate resins, polyamide resins, thermoplastic saturated resins, etc. The resin composition of the present invention has high adhesion to polyester resins, and can provide molded products with excellent properties, particularly impact strength.

The carbon fiber used as a raw material in the present invention is a commonly known polyacrylic, rayon, or pitch type, and may be either carbonaceous or graphite. Further, the carbon fiber in the present invention is preferably one whose surface has been oxidized as in the case of general use.

The polyurethane resin used in the present invention includes 1,6-hexane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, tolylene diisocyanate,
Isocyanates such as isophorone diisocyanate (A
> and ethylene glycol, butylene glycol, 1.6
- Diols (B) such as glycols such as hexanediol and bishydroxyethoxybenzene, polyester diols such as polyethylene adipate, polycaprolactone, and poly(hexamethylene adipate), or polyether diols such as polyoxytetramethylene glycol; Reaction of T” IQ Larel Toko’5 (7)
It is a so-called completely thermoplastic type linear polyurethane resin in which 0.95≦NGO101-1≦1.0.

The so-called incompletely thermoplastic polyurethane resin of NGO/○to 1>1 tends to cause a crosslinking reaction during the sizing process, and as a result, the excessive cohesiveness of carbon fibers is increased by +S.
It is coated with a mixed tan resin with a thermoplastic resin, particularly a resin with a low melt viscosity such as a polyamide resin.

The sizing port of the polyurethane resin is 0.311 here.
If it is less than m%, the cohesiveness of the fibers will be poor and the degree of improvement in adhesion between the fibers and the resin will be low.On the other hand, if it exceeds 10% by weight, the cohesiveness will be too strong, resulting in poor dispersion and a decrease in strength.

In order to coat the charcoal-N fibers with a polyurethane resin, the uli fibers are manufactured by dipping them in a solution of the polyurethane resin in a suitable solvent or a solution of the polyurethane resin dispersed in water. Substantially continuous carbon fibers having an appropriate number of filaments are continuously immersed in a polyurethane resin solution containing 0.5 to 5% mold in methyl ethyl ketone, and then passed through a hot air drying oven at 80°C to remove the solvent. , and then cut to an appropriate length with a cutter.

When charcoal*m fibers are mixed into a thermoplastic resin, the length of the fibers is not particularly limited, but from the viewpoint of workability, 0.3 to 10 mm, particularly 3 to 6 IIlffl, is preferable.

In the present invention, thermoplastic resins include generally commercially available polycarbonate resins, polyamide resins, thermoplastic saturated polyester resins (e.g., polybutylene terephthalate resins, polyethylene terephthalate resins), polyacetal 84 resins, polysulfone bfI resins, and polyethersulfone resins. Resin, polyphenylene sulfide HA
General molding resins such as styrene resins, olefin resins, and vinyl chloride resins can be used, but in particular, polycarbonate resins, polyamide resins, and thermoplastic polyester resins improve the mechanical properties of molded products. Therefore, it is suitable.

Polycarbonate resins are produced from aromatic dihydroxy compounds and carbonate precursors, such as phosgene, diphenyl carbonate, etc., by a solution method or a melt method. In this case, the aromatic dihydroxy compounds include 2,2-bis(4-hydroxyphenyl)propane (common name bisphenol A), bis(4-hydroxyphenyl)methane,
1.1-bis(4-hydroxyphenyl)cyclohexane, 2.2-bis(4-hydroxy-3-methylphenyl)propane, 2.2-bis(3,5-dibromo-4-
hydroxyphenyl)propane, 2,2-bis(3,5
-dimethyl-4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)sulfide, bis(4-
Examples include hydroxyphenyl) sulfone. A particularly preferred polycarbonate resin is a polycarbonate based on 2,2-bis(4-hydroxyphenyl)alkane, especially bisphenol A. Those having an average molecular weight of 15,000 to ioo, ooo are suitable.

In addition, as polyamide resins, nylon 6, nylon 66, nylon 11, nylon 12, nylon 6.10
etc. Furthermore, as a thermoplastic saturated polyester resin,
Examples include polyethylene terephthalate, polyethylene terephthalate, and co-polyester containing these as main components.

The carbon IN reinforced thermoplastic resin composition according to the present invention is
It contains 3 to 6 weight % of carbon fibers treated with carbon fibers and 97 to 40 weight % of thermoplastic resin.

When the carbon fiber content in the resin composition is less than 3%, the effect as a reinforcing material is small, and when it exceeds 60%, the moldability deteriorates significantly, which is not preferable in any case.

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited thereby.

Example 1 Ester-type fully thermoplastic polyurethane resin with a high molecular weight (Lisbon 6216S L manufactured by Dainippon Ink and Chemicals Co., Ltd.)
) in methyl ethyl ketone to make a polyurethane resin solution, acrylic high-strength type carbon m-fiber roving (120'00 filament) was immersed in this, and after removing the solvent in a hot air dryer at 80°C, it was removed with a roving cutter. A chopped carbon fiber strand with a length of 61IIll was produced.

At this time, the concentration of the polyurethane resin solution was adjusted, and five types of chopped strands with different sizing distances were created.

These chopped strands are thoroughly dried into nylon 66 resin pellets (2020B manufactured by Ube Industries, Ltd.) or polycarbonate resin powder (Panlite L-1250P manufactured by Konjin Kasei Co., Ltd.), each containing 30% by weight of carbon fiber.
After tri-blending a total of 3 kg in a tumbler, the mixture was melt-kneaded and extruded into a strand shape using a 4 mm vented extruder, and after cooling with water, the mixture was cut into pellet shapes to obtain a molding material. At this time, the carbon fibers remaining in the hopper of the extruder were taken out and their weight was measured. The results are shown in Table 1.

Steady operation of a system in which carbon fibers remain is difficult. For systems with remaining carbon fibers, the mixture ratio is kept the same, the mixture is put into the hopper again, and then a plastic rod is used to force the carbon fibers to 1! The miscellaneous was fed to the extruder.

After thoroughly drying the molding material having a carbon fiber content of 30% by weight thus obtained, a test piece was molded using an injection molding machine and its physical properties were measured. The results are shown in Table 2.

Comparative Example 1 Each 6n+ml chopped strand of carbon fiber without sizing treatment (no size) or carbon fiber sized with epoxy resin (Epicoat 828 manufactured by Shell Chemical Co., Ltd.) was made into nylon in the same manner as in Example 1. 66
The mixture was mixed with resin pellets, put into the hopper of an extruder, and extruded. Further, each of the chopped strands was mixed with polycarbonate resin powder and extruded in the same manner. As a result, in all cases, most of the carbon fibers remained in the hopper, making it impossible to obtain a satisfactory molding material.

The weight of each residual carbon fiber was measured. The results are also listed in Table 1.

Further, as in Example 1, the mixing ratio was again made the same, and carbon fibers were forcibly fed to the extruder using a plastic rod to obtain a molding material. After thoroughly drying this molding material, a test piece was molded using an injection molding machine and its physical properties were measured. The results are also listed in Table 2.

Example 2 The same chopped strands used in Example 1 were added to sufficiently dried polybutylene terephthalate (CL-7000 manufactured by Konjinsha) so that the carbon fiber content was 30%. After tri-blending in a tumbler, the mixture was melt-kneaded in a 40 mm vented extruder, extruded into strands, cooled with water, and made into pellets. After drying these pellets at 120°C for 4 hours, they were molded in an injection molding machine. A test piece was molded and its physical properties were measured.The results are shown in Table 3.

Comparative Example 2 Bo I The physical properties of test pieces prepared using the same no-size carbon fibers or epoxy resin-sized carbon fibers as used in Comparative Example 1 are also listed in Table 3.

According to the above, by using carbon fiber coated with 0.3 to 10% by weight of polyurethane resin, mixing with the thermoplastic resin can be carried out constantly, and the physical properties of the molded product can be significantly improved. Recognize.

Claims (1)

[Scope of Claims] (1) A carbon fiber-reinforced thermoplastic resin composition comprising 3-60% by weight of carbon fibers coated with 0.3-10% by weight of a polyurethane resin and 97-40% by weight of a thermoplastic resin. . (2) The composition according to claim (1), wherein the thermoplastic resin is a polycarbonate resin, a polyamide resin, or a thermoplastic saturated polyester resin.