JPS6189030A - Plastic screwlike molding and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a plastic screwlike molding that is reinforced highly with reinforcing fibers, and is lightweight, corrosion-resistant, chemical-resistant and electrically insulative, by making said molding of a resin composition containing a crosslinked polymer mainly consisting of a phenol formaldehyde resin and a polyamide resin. CONSTITUTION:The polyamide used is preferably a resin having amide linkages in the main chain that is used as a thermoplastic resin such as nylons. The phenolic resin used should contain reactive methylol groups per molecule in an amount between 2wt% and 15wt%. If required, reinforcing fibers are added to prepared the intended resin composition, and the composition is molded for example by injection molding. Then the molded material that may be in the shape of a column or a cylinder is formed with a thread on the outer layer section or on the inner layer section. Then the threaded material is heated at or below the melting temperature thereof or irradiated with radiation to produce the desired screwlike molding.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a plastic screw-shaped molded article and a method for manufacturing the same, and particularly to a plastic screw-shaped molded article having threads formed by rolling, lightweight, high strength, corrosion resistance, and chemical resistance. The present invention relates to a plastic screw-shaped molded product that has excellent properties and electrical insulation properties and whose mechanical strength does not decrease even at high temperatures, and a method for producing the same.

(Conventional technology) One example is a thread-shaped molded object such as a bolt.

Metal bolts have been known for a long time. This is manufactured by the rolling method, which has the fastest production speed for thread processing. Although metal bolts are manufactured with high productivity, they have the fatal disadvantage of being heavy and prone to rust. On the other hand, bolts made from lightweight and corrosion-resistant plastics are being produced.However, bolts made by injection molding of thermoplastic resins such as vinyl chloride and polycarbonate are generally not strong enough. It is weak and can only be used for specific purposes such as decoration. Among thermoplastic resins, hard vinyl chloride and polyamide are relatively hard. Polyamides such as nylon 6, nylon 6.6° and nylon MXD6 are particularly strong. It is an engineering plastic that has excellent properties such as self-lubricating properties, oil resistance, and chemical resistance.If reinforcing fibers such as glass fiber are added, it can have an even better reinforcing effect. You will get a high quality bolt with
Plastic materials that can be rolled are:

Limited to non-fiber reinforced plastic materials such as rigid PVC resin. This is because fiber-reinforced plastic materials have high strength and therefore have poor plastic deformability, making it impossible to form threads by rolling, which requires plastic deformability. Even if you forcefully roll the material.

The threads do not form a normal triangular shape, and the top of the triangle becomes two threads, or cracks occur in the threads. Therefore, it has low strength and cannot be used as a screw. On the other hand, bolts obtained by rolling a non-fiber reinforced plastic material are inferior in one strength. Its tensile strength is at most 4~
5 kg/u+2, it cannot withstand use as a bolt that requires strong fastening force.

In order to improve these problems, the following measures may be taken: ■ Adding a plasticizer such as phenol, or ■ Bringing the material into contact with a heat medium before rolling, or Heat the molding dice. ■If you take the measures mentioned above,
Generally, the rolling properties of a molded material increase, but the mechanical strength decreases as the elastic modulus decreases. By taking the measure (2), it is possible to improve the rolling properties without impairing the mechanical strength of the forming material. However, thermoplastics generally have significantly lower mechanical strength at high temperatures than at low temperatures. Polyamide resin is no exception.

Therefore, to date, no bolt has been produced that exhibits a small decrease in mechanical strength even at high temperatures and can be mass-produced by rolling.

(Problems to be Solved by the Invention) The present invention can solve the above-mentioned problems of the prior art.The purpose of the present invention is to provide a lightweight, corrosion-resistant, chemical-resistant, and electrically insulating product that is made of reinforced fibers. An object of the present invention is to provide a highly reinforced plastic screw-shaped molded body and a method for manufacturing the same. Another object of the present invention is to provide a method for manufacturing a high-strength plastic thread-shaped molded body by rolling, which is the most economical method for thread processing. Still another object of the present invention is to provide a plastic screw-shaped molded article whose mechanical properties do not deteriorate even when used at high temperatures, and a method for producing the same.

(Means for Solving the Problems) The plastic screw-shaped molded article of the present invention is made of a resin composition containing a crosslinked polymer mainly consisting of a polyamide resin and a phenol formaldehyde resin, thereby achieving the above object. .

Furthermore, the method for producing a plastic screw-shaped molded article of the present invention includes a step of molding the resin composition into a columnar or cylindrical material; rolling the molded material to form a thread on the surface layer of the molded material; The forming step includes a step of heating or irradiating the thread-formed material to a temperature below its melting point, thereby achieving the above object. The "thread-shaped molded body" as used in the present invention refers to a molded body having threads made of a resin composition obtained by heating a plastic molded body or crosslinking the molded body by shining radiation onto the molded body. say. Specifically, it refers to bolts.

The polyamide used in the present invention includes nylon 6, nylon 6/6, which is commonly used as a thermoplastic resin. Nylon 12. There are resins such as nylon MXD6 that have amide bonds in their chains. Needless to say, there is no need to be limited to this.

As a phenol resin, the reactive medylol group in the molecule is 2 wt% or more and 15 wt% of the total phenol resin.
The content below is preferably 5 wt% or more. If the amount is too small, the compatibility with polyamide will be significantly reduced, so that sufficient mechanical strength will not be achieved. Furthermore, if the content of methylol groups exceeds 15 wt%, most of the resin will be hardened during molding, as seen in resol resins, and rolling processing will become impossible.

Furthermore, the amount of phenol resin added is not particularly limited by the proportions of other components in the system.

For example, when using 50-t% of the reinforcing glass fibers described below, it is preferable to use phenol resin in an amount of 3 to 20 wt% of the total composition. If the amount is too small, the material will not be sufficiently deformed, resulting in cracks in the material during rolling. If the amount is too large, the reinforcing effect of the inorganic material on the polyamide resin will be impaired, resulting in a decrease in mechanical strength.

Furthermore, in order to facilitate the dispersion of the phenol resin into the polyamide resin, it is desirable to use it in powder form, preferably with a maximum particle size of 100 μm or less.

Examples of reinforcing fibers include glass fiber.

There are inorganic fibers such as carbon fiber, boron fiber, and silicon carbide fiber; and organic fibers such as aramid fiber. It is also possible to use a mixture of two or more of these fibers. There is no particular restriction on the length of the fibers, as long as they can be dispersed in the thermoplastic resin molded into a cylindrical or cylindrical material. These reinforcing fibers are melt-mixed with a thermoplastic resin using a kneading means such as an extruder, and are uniformly dispersed in the resin. This reinforcing fiber is used as appropriate as required.

When used, it is preferably contained in a range of 25 to 60 wt%. If reinforcing fibers are included, a high-strength plastic thread-shaped molded article can be obtained, but if the content is too large, the product will become brittle and the reinforcing effect will be reduced. It goes without saying that rolling properties and heat resistance are improved even in systems that do not contain fibers. These resins may be mixed with various additives such as fillers, processing agents for improving adhesion to fibers, flame retardants, and antioxidants, if necessary.

The plastic screw-shaped molded article of the present invention is manufactured as follows: The resin composition mainly consisting of the above-mentioned polyamide resin and phenol formaldehyde resin, and reinforcing fibers added as necessary, is prepared by a conventional method such as injection molding. It is formed into a columnar or cylindrical material. This molded material is then subjected to a rolling process to form threads on the outer surface layer of the cylindrical material or the inner surface layer of the cylindrical material.

Molded bodies with threads can be used alone as bolts, etc., but they are usually of the first order.

The molded body is heated to a temperature below the melting point of the molded body or irradiated with radiation to form a desired screw-shaped molded body.

The heating or radiation treatment promotes the reaction of unreacted tyrol groups in the phenol formaldehyde resin contained in the molded article, further increasing the thermal and mechanical strength of the molded article. In particular, when used at high temperatures of 100'C or more, conventional PVC-clad bolts break due to creep or are extremely weak against repeated stress, whereas the bolts obtained by the present invention are used at high temperatures. The methylol group reacts and becomes even stronger thermally and mechanically. Water resistant.

Chemical resistance is also improved. Radiation is 9For example, electron beam.

Includes gamma rays and others that are included in the concept of normal radiation.

(Example) The present invention will be described below with reference to Examples.

Appropriate amounts of phenol, urea and formalin were added to a formaldehyde aqueous solution acidified with hydrochloric acid and reacted once, followed by dehydration and drying. The various phenolic resins obtained were subjected to elemental analysis, and the content of methylol groups was determined in conjunction with the results of IR analysis. Various phenolic resins with different methylol group contents obtained in this way (methylol group content 2.
The weight ratio of
: Tri blended at 80. This was made into pellets with a maximum diameter of 2 mm or less using an extrusion molding machine. This was molded into a round bar with a diameter of 9.0 cm using an injection molding machine. This round bar is lQc
A cylindrical material was obtained by cutting into a length of m. This was subjected to a thread rolling machine equipped with an MIO thread die. Attach Nandos to both ends of the obtained 10cn+ length MIO bolt and heat it to JIS B 105 in a constant temperature room at 20℃.
A tensile test according to 1 was conducted. A similar test was also conducted in a constant temperature bath at 80°C. The results are shown in Table 1.

The procedure was the same as in Example 1, except that the pellets of Example 1 were tri-blended with glass fibers having a diameter of 13 μm and a length of 611 m at a weight ratio of 50:50.

The main example 2 for large-stop carbonization is the same as Example 2 except that the composition ratio of phenol resin and polyamide resin was set to 6:94.

SW E1 The same as Example 2 except that the composition ratio of phenol resin and polyamide resin in Example 2 was set to 5:95.

Example 5 This is the same as Example 2 except that the composition ratio of phenol resin and polyamide resin in Example 2 was set to 40:60.

34 Filtration Example 2 was the same as Example 2 except that the composition ratio of phenol resin and polyamide resin was 50:50.

Disaster Management Team 1 This was the same as in Example 2 except that the bolts subjected to the rolling process in Example 2 were placed in an electric furnace at 150°C for 48 hours.

Example 2 is the same as Example 2 except that the bolt is irradiated with IMrad gamma rays.

Example 1 was the same as Example 1 except that the phenol resin was not used in Example 1.

This example is the same as Example 2 except that the phenolic resin was not used in Example 2.

Main Example 2 was the same as Example 2 except that the amount of formaldehyde was adjusted so that the content of methylol groups in the phenol resin was 1.0 wt%.

Example 2 was the same as Example 2 except that the amount of formaldehyde was adjusted so that the content of methylol groups in the phenol resin was 20 wt%.

Comparative Example 2 was the same as Comparative Example 2 except that 1 wt% of phenol was added to the extruder.

Comparative Example 2 was the same as Comparative Example 2 except that the cylindrical material was brought into contact with 150''C silicone oil during rolling.

(The following is a blank space) Table 1 (Effects of the Invention) According to the present invention, it is extremely easy to perform thread forming by rolling on a plastic material highly reinforced with two-reinforced fibers. Thread forming by rolling increases productivity, so bolts can be produced economically. Moreover, the thread shape of the resulting plastic bolt is good, and the top of the thread does not become double-threaded or crack or break. When the molded material with the threads formed is subjected to heat treatment or radiation irradiation treatment, the resulting bolt has little loss of strength even when used at high temperatures, is high strength, lightweight, and corrosion resistant. It has all the characteristics inherent in fiber-reinforced plastic materials such as Tomu.

that's all

Claims (1)

[Scope of Claims] 1. A plastic thread-shaped molded article made of a resin composition containing a crosslinked polymer mainly composed of a polyamide resin and a phenol formaldehyde resin. 2. The plastic screw-shaped molded article according to claim 1, wherein the phenol formaldehyde resin contains 2 to 15% by weight of methylol groups in the molecule. 3. The plastic screw-shaped molded article according to claim 1 or 2, wherein the resin composition contains reinforcing fibers. 4. A step of molding a resin composition containing a crosslinked polymer mainly consisting of polyamide resin and phenol formaldehyde resin into a cylindrical or cylindrical material; rolling the molding material to form a thread on the surface layer of the molding material. A method for producing a plastic screw-shaped molded article, which includes the steps of: heating the material on which the thread is formed to a temperature below its melting point or irradiating it with radiation. 5. The method for producing a plastic screw-shaped molded article according to claim 4, wherein the phenol formaldehyde resin contains 2 to 15% by weight of methylol groups in the molecule. 6. The method for producing a plastic screw-shaped molded body according to claim 4 or 5, wherein the resin composition contains reinforcing fibers.