JPS6274630A - Joining of synthetic resin material - Google Patents

Abstract

PURPOSE:To strongly join both synthetic resin materials with each other by a method wherein laser beams are irradiated from the side of one of both the synthetic resin materials to heat and melt the other synthetic resin material, against the molten portion of which the one synthetic resin material formed the joining projection having engaging pieces is pressed for joining. CONSTITUTION:An irradiation nozzle 4 of a neodymium laser is positioned above the joining projection 3 formed on a plate member 2 made of styrene- acrylonitrile copolymer. When YAG laser beams 5 are irradiated from the irradiation nozzle 4 under the above-mentioned state, the joint surface 1a of a plate member 1 is quickly heated and melted by the energy of the laser beams. By being applied with load, the joining projections 3 of the plate member 2 is inserted in the molten portion of the plate member 1 one after another. Thus, the plate members 1 and 2 are strongly joined with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of joining two synthetic resin materials to be joined by irradiating a laser beam from one of the materials.

[Conventional technology]

Conventionally, when joining synthetic resin materials, a physical joining method in which heat is applied to weld them, and a chemical joining method in which they are joined together using an adhesive have been widely used.

In other words, the former physical joining method generates heat with a heating element such as a metal mesh on the joint surfaces of the synthetic resin materials to be joined, melts the joint surfaces of both synthetic resin materials, pressurizes and cools them, and performs resynthesis. This is a method of joining resin materials. In addition, the latter chemical bonding method involves interposing an adhesive such as hot melt on the bonding surfaces of the synthetic resin materials to be bonded.
In this method, high frequency or ultrasonic waves are applied to the surface of one synthetic resin material to heat and melt the adhesive, and then both synthetic resin materials are cooled while being pressurized to rejoin the synthetic resin materials.

However, in the former physical joining method, when joining synthetic resin materials of the same type, both synthetic resin materials have the same melting temperature and are compatible, so both synthetic resin materials are Although it passes through the junction of -
When joining different types of synthetic resin materials, it is difficult to join the two synthetic resin materials because their melting temperatures are different and their compatibility is poor. In addition, the latter chemical bonding method is as suitable as the former physical bonding method when bonding the same type of synthetic resin materials;
When joining different types of synthetic resin materials, the adhesive force of the adhesive decreases depending on the quality of the synthetic resin materials, making it difficult to firmly join both synthetic resin materials. Furthermore, even if the synthetic resin materials are of the same type, it is difficult to firmly bond synthetic resin materials with poor compatibility, such as polypropylene resin, in the same way as with different types of synthetic resin materials.

For the reasons described above, mechanical joining methods are often used when joining synthetic resin materials of poor compatibility, such as polypropylene, even if they are of the same or different types. A typical example thereof will be explained using a method of joining polypropylene resin and polyethylene resin as shown in FIG.

In FIG. 3, reference numeral 51 denotes a plate member made of polypropylene resin, and a plate member 52 made of polyethylene resin is disposed at the bottom of this plate member 51, and this plate member 52 of polyethylene resin and polypropylene resin Through-holes 53a and 53b are formed in opposing parts of the plate member 51.
is formed. Then, screws 55 are screwed into the H through holes 53a and 53b of both plate members 51 and 52 from above with a gasket 54 interposed therebetween, thereby joining both plate members 51 and 52.

[Problem that the invention seeks to solve]

However, in such mechanical joining methods,
Through holes 53a and 53b are formed in both plate members 51 and 52,
The screws 55 must be screwed together, which makes the joining work more complicated than the above-mentioned physical joining method and chemical joining method.
, 53b, both plate members 51
．． There is a problem that the strength of 52 is reduced.

Therefore, this first invention was made to solve the above-mentioned problems, and after irradiating a laser beam from one side of the synthetic resin material to heat and melt it, an elastic locking piece is attached to the melted part. To easily and firmly join both synthetic resin materials without reducing their strength by pressing a joining protrusion and a synthetic resin material having a hooking groove formed around it.

[Means for solving problems]

That is, in the method for joining synthetic resin materials according to the present invention, when joining the two synthetic resin materials by irradiating a laser beam from one side of the two synthetic resin materials to be joined, the lower part of the synthetic resin materials to be joined is The synthetic resin material disposed on the upper part is made absorbent to the laser beam, the synthetic resin material disposed on the upper part is made non-absorbent to the laser beam, and the lower surface of the synthetic resin material is elastically locked. A joining protrusion having a piece is formed, and a latching groove is formed around the protrusion, and the joining protrusion is brought into contact with the lower synthetic resin material, and a laser beam is irradiated from the upper part to bond the lower part. Heating the resin material
The molten material is melted, the joining protrusion is pushed into the molten part, the locking piece is entwined with the molten material, and the molten material is raised into the latching groove.

Examples of the synthetic resin material disposed in the upper part that does not absorb laser light include polyethylene resin, polypropylene resin, styrene-acrylonitrile copolymer, and the like. Further, the joining protrusion having an elastic locking piece formed on the lower surface of the synthetic resin material can be formed in one piece or in plural pieces depending on the required joining strength, and the locking piece also has a One or more can be formed. Further, the shape of the joining protrusion is not particularly limited either, and may be formed into, for example, a polygon, a column, a cylinder, a trapezoid, a cone, or the like. The latching groove formed around the joining protrusion is not particularly limited either, and may be formed in, for example, a linear shape, a hemispherical shape, a polygonal shape, a trapezoidal shape, a conical shape, or the like.

Further, the synthetic resin material disposed at the bottom may be any material as long as it has absorbency to laser light, for example,
Polyethylene resin, polypropylene resin, with addition of 0.1 to 0.3% by weight of auxiliary materials such as carbon black,
Synthetic resin materials such as styrene-acrylonitrile copolymer, polyethylene resins, polypropylene resins, styrene resins reinforced with glass fibers, and 0.1 to 0.3% by weight of auxiliary materials such as carbon blanks are added.
Examples include synthetic resin materials such as acrylonitrile copolymers.

The above-mentioned two synthetic resin materials can be freely selected and bonded in a combination such that when the synthetic resin materials are overlapped, the synthetic resin material disposed at the bottom is a synthetic resin material that is absorbent to laser light.

In addition, examples of lasers used when bonding both synthetic resin materials include glass: neodymium 3+ laser, YAG: neodymium 3+ laser, ruby laser, helium-neon laser, krypton laser, argon laser, H2 laser, N2 laser, etc. Of these, especially Y
AG:Neodymium 1+ laser and Glass:Neodymium 3+ laser are the best.

In addition, the wavelength of the laser used when bonding both materials needs to be suitable for the synthetic resin materials to be bonded, and the best wavelength is around 1.06 μm;
If the thickness is 0.6 μm or more, it becomes difficult to heat and melt the lower synthetic resin material to join. In addition, in terms of laser output, 5W to too much is passed through, and 5W
to 30W is the best. If the output is less than 5W, it will take a long time to heat and melt the synthetic resin material at the bottom, and if the output is more than 100W, the synthetic resin material at the bottom may evaporate or deteriorate. This causes the joint strength to decrease.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

(First Example) FIG. 1 is a schematic sectional view illustrating a first example of the method for joining synthetic resin materials according to the present invention.

In (a) to d) of Fig. 1, ``■'' is a plate member made of polypropylene resin, and the plate member 1 has a thickness of 1Q mm, and its upper surface is a flat joint surface. 1a, and the bottom surface is also formed flat to form a pedestal (
(not shown), etc., is the mounting surface 1b. The raw material color of this plate member 1 is black due to O.1% by weight of carbon black being mixed therein, and has the property of absorbing laser light of around 1.06 μm.

Further, a plate member 2 made of styrene-acrylonitrile copolymer is disposed on the upper part of the plate member 1, and the plate member 2 has a thickness of 15 mm. Further, the upper surface of this plate member 2 is a flat surface 2a, and the lower surface is a joint surface 1 of the plate member 1.
The joint surface 2b is in contact with a. Furthermore, a joining protrusion 3 having a cylindrical shape and a length of 5 cranes is formed on the joint surface 2b of this plate member 2, and a latching groove 3a is formed around the joint protrusion 3. There are two locking pieces 3 in the circumferential direction.
b is formed. The raw material color of this plate member 2 is transparent, and it has a non-absorbing property for laser light of around 1606 μm.

When joining both plate members 1.2, (
As shown in a), the tip of the joining protrusion 3 formed on the joining surface 2b of the plate member 2 is set in contact with the joining surface 1a of the lower plate member 1.

Next, as shown in FIG. 1(b), the irradiation nozzle 4 of the YAG:Neodymium 3+ laser device is positioned above the joining protrusion 3 formed on the plate member 2 made of styrene-acrylonitrile copolymer. let In this state, a YAG laser beam 5 having a wavelength of 1.06 μm and an output of 20 W is passed through the processing lens 6 and irradiated from the irradiation nozzle 4.

At this time, the YAG laser beam 5 is not absorbed by the plate member 2 made of styrene-acrylonitrile copolymer due to the relationship between its wavelength and the absorption spectrum of the synthetic resin material, so it is scattered inside the plate member 2. The light then passes through while repeating refraction and reaches the joint surface 1a of the plate member 1 made of polypropylene resin.

The YAG laser beam 5 that reaches the plate member 1 is accumulated as energy in and around the plate member 1, and the joint surface 1a of the plate member 1 is quickly heated and melted by the energy.

Then, while sufficiently heating and melting the plate member 1 with the YAG laser beam 5, as shown in FIG.
Applying a load from the direction, the joining protrusions 3 of the plate member 2 are sequentially inserted into the melted portion of the plate member l. At that time, the molten material 1c of the plate member 1 rises to the upper plate member 2 side, and the latching groove 3a
At the same time, the locking piece 3b of the joining protrusion 3 acts to restore its original state by elastic force and becomes entangled with the molten material IC.

Then, the joint surface 2b of the upper plate member 2 is connected to the lower plate member l.
Irradiation of the YAG laser beam 5 is continued until the YAG laser beam 5 contacts the bonding surface 1a, and a load is continuously applied from the direction of arrow A.

Then, when the joint surfaces 1a and 2b of both plate members 1.2 are brought into sufficient contact, the irradiation of the YAG laser beam 5 is stopped, and the load on the plate member 2 from the direction of the arrow is removed. After that, the irradiation nozzle 4 is moved away from the plate member 2.

As a result, as shown in FIG. 1(d), the joining protrusion 3 formed on the joining surface 2b of the plate member 2 bites into the melted part of the plate member l, and the locking piece 3b touches the melted material 1c. At the same time, part of the molten material 1c is naturally hardened while being accommodated in the latching groove 3a, and the plate member 1 made of polypropylene resin is
and the plate member 2 made of styrene-acrylonitrile copolymer are firmly joined.

(Second Example) FIG. 2 is a schematic sectional view illustrating a second example of the method for joining synthetic resin materials according to the present invention.

This second embodiment is similar to the first embodiment in many respects;
Identical parts will be given the same numbers, explanations thereof will be omitted, and only differences will be described.

The difference in the second embodiment is that the plate member 1 made of polypropylene resin has 20 fins, the plate member 2 made of styrene-acrylonitrile copolymer has 5 fins, and the joining protrusion 3 is made longer. In addition, a large number of locking pieces 3b are formed by making them thinner. When joining both plate members 1 and 2, the joining operation is performed in the same manner as in the first embodiment.

As a result, the joining surface 2 of the plate member 2 as shown in FIG.
The joining protrusion 3 formed at b bites into the melted part of the plate member 1, and the locking piece 3b gets entangled with the melted material IC, and
A portion of the molten material 1c is naturally hardened while being accommodated in the latch 'a3a, and the plate member 1 made of polypropylene resin and the plate member 2 made of styrene-acrylonitrile copolymer are firmly joined.

In addition, in the i-th example and the second example described above,
Although the combination of the plate member 1 made of polypropylene resin and the plate member 2 made of styrene-acrylonitrile copolymer has been described, the present invention is not limited to this combination, and the present invention is not limited to this combination. It is possible to freely select and bond a combination of a synthetic resin material and an absorbent, low-melting point synthetic resin material.

Further, the laser beam used when joining both plate members 1.2 is not limited to YAG laser beam, and it is natural that similar effects can be obtained even if other laser beams are used.

〔Effect of the invention〕

As explained above, in the method for joining synthetic resin materials according to the present invention, after irradiating a laser beam from one side of the synthetic resin material to heat and melt it, an elastic locking piece is provided at the melted part. Since the joining protrusion and the synthetic resin material with the latching groove formed around it are pressed and joined, it is possible to join the two synthetic resin materials without reducing their strength. .

Further, in the present invention, since the joining protrusion having the elastic locking piece formed in the upper synthetic resin material is inserted into the melted part of the lower synthetic resin material to join them, both This has the effect of making it possible to bond synthetic resin materials more strongly.

In addition, in the present invention, since the laser beam is irradiated from one side of the synthetic resin materials to join them, it is easier to join the synthetic resin materials compared to the conventional mechanical joining method using screws. There is an effect that can be done.

Further, in the present invention, when the synthetic resin materials are joined, there is no fixing means such as screws at the joined portion of the two synthetic resin materials, so there is an effect that the design effect can be improved.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view illustrating a first embodiment of the method for joining synthetic resin materials according to the present invention. FIG. 2 is a schematic cross-sectional view illustrating a second embodiment of the method for joining synthetic resin materials according to the present invention. FIG. 3 is a schematic cross-sectional view illustrating a conventional method of joining synthetic resin materials. ■--Plate member 1c--Melted material 2--Plate member 3--Joining protrusion 3a--Latching groove 3b--Latching piece 4-- ......Irradiation nozzle 5-...YAG laser beam 6-...Processed lens applicant Toyota Motor Corporation (a) <'D) Figure 1 Factor 3

Claims (1)

[Claims] When joining two synthetic resin materials by irradiating a laser beam from one side of the two synthetic resin materials to be joined, the synthetic resin material disposed at the lower part of the synthetic resin materials to be joined is made absorbent to the laser beam. The synthetic resin material disposed on the upper part is non-absorbent to laser light, and the lower surface of this synthetic resin material is formed with a joining protrusion having an elastic locking piece. A retaining groove is formed, the joining protrusion is brought into contact with the lower synthetic resin material, the lower synthetic resin material is heated and melted by irradiating laser light from the upper part, and the joining protrusion is placed in the melted area. 1. A method for joining synthetic resin materials, the method comprising: pushing a part into the latching groove, entangling the latching piece with the molten material, and causing the molten material to bulge in the latching groove.