JPS6218428A - Ceramic fiber-containing composite plastic - Google Patents

Abstract

PURPOSE:To obtain a fiber-reinforced plastic improved in surface smoothness, dimensional stability, mechanical strength, sliding property and coloration, by adding a ceramic fiber to a plastic material. CONSTITUTION:A composite plastic comprising 5-60wt% ceramic fiber and the balance of a plastic material. It is preferable to remove thicker fibers contained so that most of the fibers have thicknesses distributed within the range of 0.1-4.0mu because the finer they are, the more the surface smoothness and sliding property can be improved when they are used as a filler for a plastic. It is also desirable that the content of shots of a particle diameter >=44mu in the ceramic fiber is 20% or below, and it is desirable to remove coarse shots so that the sizes of shots contained may be 150mu or below.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ceramic fiber composite plastic having excellent mechanical properties, dimensional stability, surface smoothness, sliding properties, colorability, etc.

[Conventional technology]

Conventionally, plastics are filled with various inorganic fII iron slants such as glass fibers, potassium titanate fibers, carbon fibers, calcium carbonate, silica, magnesium carbonate, mica, glass beads, alumina fibers, and silicon carbide fibers. It is well known to improve strength, dimensional stability, etc.

[Problem to be solved by the invention J However, although glass fiber is the most widely used inexpensive fibrous filler, its fiber diameter is usually 6 to 16 μm, and it is easy to orient, so it is difficult to fill it with glass fiber. Plastics have problems such as lack of surface smoothness, poor sliding properties, and directional molding shrinkage.

Among the glass fibers, there are special types with fiber diameters of 0°7~
There is a material as thin as 3μ, which solves the problems of the glass fiber-filled plastic mentioned above, but it has the disadvantage of being extremely expensive.

There are two types of alumina fibers: alumina fibers and mullite fibers.
There are short fibers with a fiber diameter of about 3 μμ and continuous long fibers with a fiber diameter of 9 μμ. Short fibers with a fiber diameter of about 3 μm were developed as a heat insulating material, and their own strength is low, so they cannot be kneaded with resin.
The fibers are severely bent during molding, making it unsuitable as a filler. Long fibers with a fiber diameter of 9 to μμ are heat resistant,
It has high strength and high modulus of elasticity and was developed as a reinforcing material, but in addition to being extremely expensive, the fibers are thick and have the same problems as regular glass fibers.

Silicon carbide fiber is a reinforcing fiber that is heat resistant, has high strength, and has a high modulus of elasticity. However, in addition to the disadvantage that it is extremely expensive, the fiber is thick at 10 to 15 μm, making it similar to ordinary glass fiber. There is a problem.

Carbon fiber is widely used as a reinforcing material having high strength and high modulus of elasticity, but in addition to being expensive, it also has the problem of not being able to add color to composite reinforced plastics.

Potassium titanate fiber has excellent fiber strength and elastic modulus, and the fiber diameter is extremely thin (0.1 to 0.3μ, so it is reinforced with fibers).Lastic has high mechanical strength and excellent surface smoothness and sliding properties. Although it has extremely excellent properties as a reinforcing material, such as having no directionality in molding shrinkage, it has the disadvantage of being very expensive and has the problem of poor colorability.

Furthermore, those filled with non-fibrous materials such as calcium carbonate, magnesium carbonate, mica, and glass beads have a drawback of poor mechanical strength.

[Failure to solve the problem]

The purpose of the present invention is to provide a fiber reinforced plastic (FRP) that improves the drawbacks of the prior art, such as surface smoothness, dimensional stability, mechanical strength, sliding properties, and colorability. The above object is achieved by providing a ceramic fiber composite plastic according to the claims.

Ceramic fibers are generally made by electrically melting approximately equal amounts of silica and alumina of crystal purity, and then blowing out the trickle with high-pressure air to make the fibers masculinized.
Unlike glass fiber, which softens at 0 to 300°C, it does not crystallize unless the temperature reaches 850°C or higher, and has excellent fire resistance that can withstand high temperatures of 1000°C or higher. Furthermore, most of the fiber thicknesses are distributed within the range of 0.1 to 6/j, and the fibers are characterized by being extremely thin, with an average of around 2μ. The thinner the fibers, the better the surface smoothness and sliding properties when filled into plastic.Thus, by removing the thicker fibers contained in ceramic fibers, most of the fibers are 0.1~
It is preferable to distribute the particles within a range of 4.0 μm. Furthermore, when the above-mentioned trickle is made into fibers, shot that is not made into fibers, shot that remains attached to the tips of the fibers,
Furthermore, shots that break off from the tips of the fibers occur. The size of this shot is generally coarse if it is not fiberized from the beginning, and many have a particle size of 150 Ij or more. In addition, the tips of the fibers or those separated from the fibers are generally as thin as 44 to 100/j, and these account for most of the shots. Ceramic fibers produced by the above method usually contain about 50% shot having a particle size of 44 μm or more, which is another characteristic of ceramic fibers.

Since shot is mainly spherical, it does not contribute to reinforcing the plastic, and coarse shots have negative effects such as impairing the smoothness of the surface, but on the other hand, it has the effect of reducing the directionality of shrinkage of molded products. It also has For this reason, the particle size 4 contained in ceramic fibers is
The amount of shots larger than 4μ is preferably 20 inches or less, and it is preferable that coarse shots are removed and the size of the included shots is 150μ or less.

A method for obtaining ceramic fibers used in the present invention whose fiber diameters are mostly within the range of 0.1 to 4.0 microns and whose shot content is 20 inches or less will be described.

Commercially available ceramic fibers are placed in water and stirred to create a ceramic fiber slurry.

Next, this slurry is gradually introduced into a cylindrical container, and at the same time,
Pressurized water is pumped through the side wall of this container to generate a thin stream, and the ceramic fibers are loosened in the thin stream to separate the Shirot. A slurry of disentangled ceramic fibers is sequentially flowed out from the center of the thin stream and guided onto a moving endless screen to collect the fibers. The ceramic fiber thus obtained has, for example, a shot content of 18% having a particle size of 44 μm or more, and a fiber diameter within a range of 0.1 to 3.5 μm, with an average diameter of 1.6 μm. Alternatively, the content of shot having a particle size of 44μ or more is μ%, and the fiber diameter is within the range of 0.1 to 8.0μ, with an average of 1.3μ.

Next, the ceramic fiber length used in the present invention will be explained. Ceramic fibers are a collection of fibers of various lengths, ranging from nearly powder-like fibers to those with a length of about 250 mm. The length of the ceramic fiber has a great effect on the mechanical strength of the plastic, and the longer it is, the better the mechanical strength will be, but if it is too long, the uniform mixability and dispersibility with the 1st lath nut will decrease, so it should be less than 500μ. is desirable. A more preferable length of the fibers is an average length of 50 to 150 microns.

A method for obtaining ceramic fibers having a 1a diameter in the range of 0.1 to 500μ for use in the present invention will be described.

Commercially available ceramic fibers are formed into mats, blankets, or sheets without the use of binders. Next, this molded body is inserted between rollers or flat plates and pressed to cut the ceramic fibers. The ceramic fiber thus obtained has a fiber length, for example, in a range of 0.1 to 500μ, with an average length of 125μ.

Furthermore, the ceramic fibers used in the present invention are advantageously treated with a silane cassophizing agent.

This is to improve the adhesion between the ceramic fibers and the 7" plastic. Plastics filled with ceramic fibers whose surface has been treated with a 7" springing agent have higher mechanical strength than those filled with untreated ceramic fibers. is excellent.

Next, the plastic used in the present invention will be explained.

Examples of plastics used in the present invention include epoxyphenol, urea, melamine, impure polyester, diallyl phthalate, silicone, polyurethane, and vinyl chloride.
and polyvinyl real alcohol, polyethylene, polypropylene, alkyl nitrile styrene terephthalate. polyethylene terephthalate.

Polyphenylene oxide, polycarbonate, nylon 6, nylon 66, polyacetal, polystyrene terephthalate, polyether → no-phon, polyphenylene sulfide, polyimide, polyether ether keto 7, tetrafluorinated ethylene, trifluorinated ethylene etc. are advantageous.

Next, the reason for limiting the amount of ceramic fibers filled in the plastic snack in the present invention will be explained.

If the ceramic fiber filling amount is less than 5 wt%, the mechanical strength of the composite plastic will be insufficient, and if it exceeds 60 wt%, the impact resistance, surface smoothness, sliding properties, moldability, etc. will decrease, so the ceramic fiber filling amount is The amount is 5~
It is necessary to keep it within the range of 5Qwt%.

Next, a method for mixing, kneading, and molding ceramic fiber and plastic will be exemplified.

First, in the case of thermoplastic plastics, plastic raw materials in the form of chips or powder and ceramic fibers are mixed in advance, the mixed raw materials are put into an extrusion molding machine, and the plastic is kneaded with the ceramic fibers while melting. After thorough kneading, the kneaded mixture of plastic and ceramic fiber is extruded through an extruder to obtain a pellet of ceramic fiber composite plastic. Next, a ceramic fiber composite plastic of a predetermined shape is obtained by injection molding using this V-cut as a raw material.

On the other hand, in the case of thermosetting plastics, ceramic fiber mats, blankets, sheets, etc. are impregnated with solution-like plastic raw materials, and then heat pressed to form them into a predetermined shape. After the ceramic fibers are added to the plastic raw material and kneaded, a ceramic fiber composite plastic of a predetermined shape is obtained by injection molding.

[Action and effect]

The plastic of the present invention is a plastic filled with ceramic fibers having various properties as described above, and has the following functions and effects.

First, since ceramic fibers have extremely small fiber diameters, plastic snacks filled with ceramic fibers have excellent surface smoothness and sliding properties, and are also excellent in blue color.

Second, ceramic fibers contain shot and have a small fiber diameter, so the orientation of the fibers during molding is low, and the directionality and shrinkage rate of molding shrinkage are low, so the filled molded product may warp. Extremely small.

Furthermore, the mechanical strength of ceramic fibers is
Tensile strength 160 to 4-1 tensile modulus 5400KV-
Because it is large and has a thin fiber diameter, it is less likely to break during molding, and even if it does break, it has a large aspect ratio, so plastic filled with it has high mechanical strength.

〔Example〕

Next, the present invention will be explained with reference to examples.

Example 1 The diameter of the fiber whose surface was coated with the aminorane coupling agent was mostly within the range of 0.1 to 4μ, with an average diameter of 1.6μ.
The fiber length is mostly within the range of 0.1 to 500μ, with an average of 1
Ceramic fibers with a shot content of 25μ, shot content of 18, and nylon 6 resin pellets were blended in the proportions shown in Table 1, mixed and kneaded in an extruder, and then injection molded to produce the ceramic fiber composite plastic of the present invention. Obtained.

Example 2 Most of the fibers whose surfaces were coated with Ami2/silane yarn coupling agent had a diameter in the range of 0.1 to 8.0ti, an average of 1.3μ, and a fiber length of mostly 0.1 to 500μ. Ceramic fiber composite plastic of the present invention was prepared by blending pellets of ceramic fiber part acetal copolymer with an average of 125μ and a shot content of μ% within the range in the proportions shown in the IT table and using the same method as in Example 1. I got it.

Example 3 The fiber diameter is mostly within the range of 0.1 to 6 tt, with an average of 2
．． Ceramic fibers with a fiber diameter of 0μ, mostly within the range of 0.1 to 500μ, an average of 125μ, and a shot content of 48, and polyphenylene oxide resin pellets were mixed in the ratio shown in Table 1. A ceramic fiber composite plastic of the present invention was obtained in the same manner as in Example 1.

Example 4 Most of the fibers whose surfaces were coated with an aminosilane coupling agent had a diameter within the range of 0.1 to 6μ, with an average diameter of 1.6μ.
The fiber length is mostly within the range of 0.1 to 500μ, with an average of 1
A ceramic fiber composite plastic of the present invention was obtained in the same manner as in Example 1 by blending ceramic fibers of 25 μm and shot content of 18% and pellets of polybutylene terephthalate resin in the proportions shown in Table 1. .

Example 5 The diameter of the fibers whose surfaces were coated with an aminosilane coupling agent was mostly within the range of Oμ to 3μ, with an average of 1.3μ, and the fiber length was mostly within the range of Oμ to 500μ, with an average of 125μ.
A ceramic fiber composite plastic of the present invention was obtained in the same manner as in Example 1 by blending ceramic fibers with a shot content of μ% and pellets of polycarbonate wood in the proportions shown in Table 1. .

The following physical property evaluation tests were conducted on the ceramic fiber-filled plastics of Examples 1 to 5 above, and the results are shown in Table 1.

Tensile strength ASTM D 638 Flexural modulus ASTM D 790 Impact strength AS
TM D 256 As shown in Table 1, ceramic fibers have a reinforcing effect when combined with plastics, so the ceramic fiber composite plastics of the present invention have high mechanical strength and a surface It has excellent smoothness and small directional molding shrinkage, making it suitable for various machines, equipment housings, precision machine parts, etc.

Claims (1)

[Claims] 1. Ceramic fiber composite plastic consisting of 5 to 60 wt% ceramic fibers and the remainder plastic material. 2. The ceramic fiber composite plastic according to claim 1, wherein the diameter of the ceramic fibers is mostly within the range of 0.1 to 4μ. 3. The ceramic fiber composite plastic according to claim 1 or 2, wherein the length of the ceramic fibers is mostly within the range of 0.1 to 500μ. 4. The ceramic fiber composite plastic according to any one of claims 1 to 3, wherein the ceramic fiber has a shot content of 20% or less. . 5. The ceramic fiber composite plastic according to any one of claims 1 to 4, wherein the ceramic fiber has shot particles contained therein having a particle size of 150 μm or less. 6. The ceramic fiber composite plastic according to any one of claims 1 to 5, wherein the surface of the ceramic fiber is coated with a silane coupling agent.