JPH0420374B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a.Objective of the invention (industrial application field) This invention provides a liquid-tight system for a synthetic resin tank for a heater core of an automobile heater and a water pipe for water supply and drainage provided in this tank. Can be used when joining to.

(Prior Art) As means for liquid-tightly joining synthetic resin parts to each other, methods using screws and O-rings, methods using adhesives, methods using heat welding, etc. are conventionally known. . Among these methods, heat welding is a joining method in which a metal is interposed in the joint, the metal is heated by high-frequency induction heating, and the joining surfaces of thermoplastic synthetic resin parts are heated and welded, and the joining surfaces are strongly pressed together. BACKGROUND ART A method of joining synthetic resin parts together using a high frequency induction heating method is known, in which synthetic resin parts are joined together in a liquid-tight manner.

Such joining methods include, for example, the generation described in US Pat. No. 3,461,014. In this invention, when joining synthetic resin parts made of the same material, an adhesive mixed with ferromagnetic powder such as magnetic iron oxide is applied to the bonding surface, and this ferromagnetic powder is applied to a high-frequency induction heating coil. By generating heat, the joint surfaces of the synthetic resin parts to be joined are melted, and together with the action of the adhesive, the synthetic resin parts are strongly bonded together. However, according to experiments conducted by the present invention, when attempting to generate heat using the high frequency induction heating method using adhesives mixed with ferromagnetic powder, ultrahigh frequency induction heating coils of 2 to 27 MHz, which are popular in the United States, are used. Although it is possible to generate sufficient heat, the 100-450 KHz high-frequency induction heating coils that are popular in Japan do not generate enough heat and cannot perform bonding.

Furthermore, as described in Japanese Patent Application Laid-open No. 48-49828, a wire mesh is interposed between the joint surfaces of synthetic resin parts, and the wire mesh is heated by high-frequency induction heating to melt the synthetic resin at the joint surface. There is a method of bonding by strongly pressing the bonding surfaces together. However,
This type of joining method works well when the joining area is relatively large, but when the joining area is narrow and the shape of the joining surface is relatively complex, such as an annular shape, such as when joining a pipe to a synthetic resin tank, The work of forming the wire mesh into a predetermined shape or properly aligning the wire mesh with the joint surface becomes troublesome. Furthermore, JP-A-53-
As described in Publication No. 58582, a method of melting and joining the joining surfaces of synthetic resins by interposing a heating conductor such as iron wire in the joining part and generating heat from this heating conductor using high-frequency induction heating method. However, in cases where hot water is repeatedly supplied to joints such as radiators and heater cores, and the temperature rises and falls rapidly, cracks are likely to occur in the joints due to the difference in thermal expansion between the synthetic resin and the heating conductor. This can easily cause water leakage failures.

For this reason, the present inventor first developed a method for joining synthetic resin parts together by sandwiching a joining part made of a thermoplastic synthetic resin mixed with metal fibers between joining surfaces, and heating the joining part by high-frequency induction. Invented parts for the machine (Japanese Patent Application No. 165085/1985).

The joining parts according to the present invention include a thermoplastic synthetic resin made of the same material as the synthetic resin parts to be joined.
The volume mixing ratio with respect to the thermoplastic synthetic resin is 7~
40% of metal fibers and 0.1 to 2.0% by weight of a coupling agent are added to the total amount of this thermoplastic synthetic resin and metal fibers, and can be freely sandwiched between the bonding surfaces of the synthetic resin parts to be bonded. When joining synthetic resin parts together, as shown in FIG. The high-frequency induction heating coil 4 is energized while being held between the bonding surfaces of the synthetic resin parts 2 and 3 and pressing the synthetic resin parts 2 and 3 toward each other. As a result, the metal fibers mixed in the joining part 1 generate heat, melting the synthetic resin constituting the joining part and the synthetic resin on the joint surfaces of the two synthetic resin parts 2 and 3, and both molten resins melt. After mixing, cooling and solidifying these molten resins, both synthetic resin parts are integrally joined in an airtight and liquidtight manner.

(Problems to be Solved by the Invention) However, the above-mentioned parts for joining synthetic resin parts according to the earlier invention still have the following problems.

That is, in the joining component according to the previous invention, the direction in which the metal fibers mixed in the thermoplastic synthetic resin are arranged was not particularly determined, but according to the experiments of the present inventor, the direction in which the metal fibers were arranged was determined by high-frequency induction heating. In particular, it has been found that the efficiency deteriorates when the direction of the magnetic flux generated by energizing the high-frequency induction heating coil 4 and the direction of the metal fibers do not match.

The present invention has been made to address such problems.

b. Structure of the invention (means for solving problems) The parts for joining synthetic resin parts of the present invention are:
As in the case of the joining parts according to the earlier invention mentioned above, the volume mixing rate in the thermoplastic synthetic resin is 7 to 40%.
of metal fibers and further add 0.1 to 2.0 of this total amount.
% by weight of the coupling agent, but in the present invention, the metal fibers mixed into the thermoplastic synthetic resin are further mixed in the direction of the magnetic flux generated by the high-frequency induction heating coil during the joining process. Arranged.

In addition, such parts for joining synthetic resin parts are made by injection molding or extrusion molding of thermoplastic synthetic resin mixed with metal fibers, but it is not possible to mix metal fibers during this injection or extrusion molding. The direction in which the thermoplastic synthetic resin flows is made to match the direction of the magnetic flux applied by the high-frequency induction heating coil during use, at least in the state immediately before cooling and solidification.

That is, when the joining parts of the present invention are manufactured by injection molding, a thermoplastic synthetic resin mixed with metal fibers and heated and melted is injected into a mold as shown in FIG. This metal is made by resin molding by combining a first half piece 6 having a cylindrical convex portion 5 and a second half piece 8 having an inner hole 7 having an inner diameter larger than the outer diameter of the cylindrical convex portion 5. A cylindrical space 9 is formed, and a disc-shaped (or conical) flow path 11
is provided. When injection molding the joining parts, the injection channel 1 opened at the end face of the second half piece 8
0 from the nozzle 12 in advance,
Inject heated and melted thermoplastic synthetic resin. The synthetic resin sent into the injection channel 10 is
1 into the cylindrical space 9, in which case the synthetic resin flows in the axial direction of the cylindrical space 9. Therefore, the metal fibers 13 mixed in the thermoplastic synthetic resin are also oriented in the axial direction of the cylindrical space 9, as shown in FIG. Once the thermoplastic synthetic resin injected into the cylindrical space 9 has cooled and solidified, the first and second halves 6 and 8 are separated and metal fibers are mixed into the thermoplastic synthetic resin to form a part into a cylindrical shape. Take out the plastic synthetic resin. At this time, in order to separate the synthetic resin still attached to the first half piece 6 from the first half piece 6, the protruding pins 14, 14 are attached to the first half piece 6.
is provided so that the synthetic resin that remains fitted onto the cylindrical convex portion 5 can be pushed out.

Furthermore, when the joining parts of the present invention are made by extrusion molding, as shown in FIG.
Thermoplastic synthetic resin mixed with metal fibers and heated and melted is continuously extruded from the annular opening of an extrusion die having a diameter of 7. Since the extrusion direction of the synthetic resin and the axial direction of the formed cylindrical part coincide, the metal fibers 13 mixed into the synthetic resin are oriented in the axial direction of the cylindrical part.

In this way, cylindrical parts obtained by injection molding or extrusion molding of thermoplastic synthetic resin are cut in a direction perpendicular to the axis using a cutter, and then joined into annular shapes as shown in Figures 4 and 5. It is designated as part 1. In this joining component 1, the metal fibers 13 mixed into the thermoplastic synthetic resin are oriented in the front and back directions of the component 1.

In this way, the metal fibers mixed in the thermoplastic synthetic resin constituting the joining parts were discarded in the front and back directions of the joining parts, so that the synthetic resin parts 2 and 2 to be joined, as shown in FIG. When this joining part 1 is sandwiched between the joining surfaces of 3 and the high frequency induction heating coil 4 provided around the joining part 1 is energized, the direction of the magnetic flux 18 generated around this high frequency induction heating coil 4 and As a result of the alignment of the metal fibers 13, an induced current is effectively generated in the metal fibers 13. For this reason, the metal fibers 13 generate heat well, and the thermoplastic synthetic resin constituting the joining part 1 and the synthetic resin on the joining surfaces of the synthetic resin parts 2 and 3 are effectively melted.

The thermoplastic synthetic resin constituting the joining part 1 is made of the same material as the synthetic resin parts 2 and 3 to be joined, and the metal fibers mixed therein can be made of a metal that generates an induced current due to electromagnetic induction. Yes, but
Ferromagnetic metals such as iron or iron-based alloys are suitable, and when made into fibers, the diameter is 8~
A diameter of 120μ and a length of about 2 to 18 mm can be used, but more preferably a diameter of 40 to 60μ and a length of 3 mm.
~4mm. Such metal fibers are mixed into the above-mentioned thermoplastic synthetic resin at a volume mixing rate of 7 to 40%, but this mixing ratio varies depending on the diameter and length of the metal fibers, and is preferably 40 to 40% in volume. Mix 15-30% of metal fibers with a size of 60μ and a length of 3-4 mm.

By modifying the surface of metal fibers, coupling agents improve the bonding property or affinity between the thermoplastic synthetic resin and the metal fibers that make up the joining parts, and also improve the bonding properties between the metal fibers and the thermoplastic synthetic resin. By improving the plasticity of the mixture and reducing the viscosity during melting, the workability of parts to be joined is improved and the work of joining synthetic resin parts is made more efficient. Such a coupling agent is appropriately selected depending on the type of thermoplastic synthetic resin and metal. For example, when nylon is used as the thermoplastic synthetic resin and iron is used as the metal, A-187 (γ-
glycidoxypropyltrimethoxysilane),
Silane coupling agents such as C-A0700 (aminoethylaminopropyltrimethoxysilane), C-M8550 (methacryloxypropyltrimethoxysilane), and PSX084 can be used. Such a coupling agent is added in an amount of 0.1 to 2.0% by weight based on the total amount of the thermoplastic synthetic resin and metal fiber.

As mentioned above, joining parts are used by mixing thermoplastic synthetic resin, metal fibers, and a coupling agent and forming them into a predetermined shape. calcium,
Fillers such as talc, pigments, etc. may be mixed.

(Example) Next, examples of the present invention will be described.

Example 1 A tank and a water pipe made of nylon 66 were used as fitting synthetic resin parts.

The joining parts were made of 79.8 parts by weight of nylon 66, 234 parts by weight of iron fibers with a diameter of 60μ and a length of 3 mm (volume mixing rate: 30%), and 1.5 parts by weight of aminoethylaminopropyltrimethoxysilane as a coupling agent. The added ingredients are stirred and mixed in advance, extruded into a string shape with a diameter of about 1.5 mm using a screw type kneading extruder under heating conditions of 270 to 290°C, cooled, and cut into lengths of 2 to 3 mm using a cutter. It was cut into pellets. This pellet is put into an injection molding machine at a cylinder temperature of
It is injection molded into a cylindrical shape under the conditions of 270 to 280℃ and a mold temperature of 80 to 120℃, and this cylindrical material is cut to a predetermined thickness with a cutter to obtain the joining parts shown in Figures 4 and 5. Obtained. As shown in FIGS. 4 and 5, this joining component has metal fibers arranged in a straight line in the thickness direction. This joining part is held between the tank and the liquid pipe in the state shown in Figure 1,
While the parts to be joined were lightly pressurized from both sides by the tank and the liquid pipe, electricity was applied for 5 seconds to a high-frequency induction heating coil with an output of 7 KW and a frequency of 400 KHz, which was installed near the parts to be joined. As a result, the nylon 66 that makes up the joining parts and the nylon 66 that makes up the joining surfaces of the tank and liquid passage pipe melt, and the joint becomes airtight and liquid-tight, achieving strength equal to or higher than that of the base material. It was done. Furthermore, the joined tank and fluid pipe were assembled into an automobile radiator, and hot and cold water were sent in alternately at regular intervals to repeatedly apply thermal shock, but airtightness and liquid-tightness were completely maintained. However, the adhesive strength did not decrease.

Example 2 The pellets obtained in Example 1 were fed into an extruder and heated to 270 to 280°C.
It was extruded into a pipe shape from a pipe-forming die heated to 280°C, cooled with air and taken off by a take-off machine, and cut into a predetermined thickness to make joining parts.

When a tank fluid passage pipe was joined using this joining part in the same manner as in Example 1, the same results as in Example 1 were obtained.

c. Effects of the Invention Since the parts for joining synthetic resin parts of the present invention and the method for manufacturing the same are constructed as described above, it is possible to join synthetic resin parts together in an attractive and strong manner, which is an advantage of the earlier invention. In addition to the effect, it is possible to save the amount of electricity and time required for bonding.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing the state in which synthetic resin parts are joined together using the joining part of the present invention, Figure 2 is a state in which the joining part of the present invention is made by injection molding, and Figure 3 is also shown in extrusion. 4 is a perspective view of the joining part of the present invention, FIG. 5 is a sectional view taken along line A-A in FIG. 4, and FIG.
The figure is a sectional view showing the joining method of the previous invention. 1: Joining parts, 2, 3: Synthetic resin parts,
4: High frequency induction heating coil, 5: Cylindrical convex part,
6: first half piece, 7: circular hole, 8: second half piece,
9: Cylindrical space, 10: Injection channel, 11: Channel,
12: nozzle, 13: metal fiber, 14: protruding pin, 15: die, 16: die land, 17: air flow path, 18: magnetic flux.

Claims (1)

[Scope of Claims] 1. In a thermoplastic synthetic resin made of the same material as the synthetic resin parts to be joined, metal fibers with a mixing ratio of 7 to 40% by volume with respect to this thermoplastic synthetic resin, and this thermoplastic synthetic resin and 0.1 to total amount with metal fibers
2.0% by weight of a coupling agent is added to the part for joining synthetic resin parts, which has a shape that can be freely sandwiched between the joint surfaces of the synthetic resin parts to be joined, and the metal fibers are joined together. Parts for joining synthetic resin parts that are oriented in the direction of magnetic flux generated by a high-frequency induction coil that is sometimes installed near the joining parts. 2 In a thermoplastic synthetic resin made of the same material as the synthetic resin parts to be joined, metal fibers with a volume mixing ratio of 7 to 40% with respect to this thermoplastic synthetic resin, and the total amount of this thermoplastic synthetic resin and metal fibers. 0.1~
2.0% by weight of a coupling agent is added to the part for joining synthetic resin parts, which has a shape that can be freely sandwiched between the joint surfaces of the synthetic resin parts to be joined, and the metal fibers are joined together. A method of manufacturing parts for joining synthetic resin parts that are oriented in the direction of magnetic flux generated by a high-frequency induction coil sometimes installed near the parts to be joined, in which a thermoplastic synthetic resin mixed with metal fibers before cooling and solidification is used. A method for manufacturing parts for joining synthetic resin parts, in which the flux is caused to flow in a direction that matches the direction of magnetic flux when the joining parts are used, and then cooled and solidified.