JPS61188128A - Bonding of synthetic resin materials - Google Patents

Abstract

PURPOSE:To enable to bond synthetic resin materials easily and strongly by a method wherein one of synthetic resin material is made of a material, which transmits laser beams and the other is made of a material, which does not transmit laser beams, and, in addition, synthetic resin material with heat resistance is arranged between said materials and laser beams are irradiated from the direction of the laser beam transmitting material without decreasing the intensity. CONSTITUTION:A plate member 21 does not transmit laser beams having wavelengths of 1.06mum or less, because the color of raw material of the plate member 21 is due to carbon black mixed therein. A polypropylene resin plate member 23, which transmits laser beams having wavelengths of 1.06mum or less, is arranged onto a thin plate 22. In order to join both the members 21 and 22, the tip of the irradiation nozzle 5 of YAG:Nd<3+> laser is abutted against the top face of the polypropylene resin plate member 23 so as to apply load in the direction indicated with the arrow B and at the same time to irradiate YAG laser beams. [See Fig. (c).] Under the state as mentioned above, the polypropylene resin plate member 23 transmits YAG laser beams in the relation between the wavelengths of the beams and the absorption spectra of the synthetic resin material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of overlapping synthetic resin materials and irradiating laser light from one of them to join them together.

[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, in the former physical joining method, when the synthetic resin materials to be joined are of the same type, there is a method of applying ultrasonic waves or vibrations to the resynthetic resin material and welding it. This is a method of joining re-synthetic resin materials by generating heat with a heating element such as a metal mesh on the joining surfaces of the synthetic resin materials to be joined, melting the joining surfaces of both synthetic resin materials, and pressurizing and cooling them. The latter chemical bonding method involves interposing an adhesive such as hot melt on one surface of the synthetic resin materials to be bonded, and applying ultrasonic waves to the surface of the other synthetic resin material. After heating and melting the adhesive, both synthetic resin materials are cooled while being pressurized, and the resynthetic resin materials are joined together.

However, in the former physical joining method, when joining the same type of synthetic resin materials, the melting temperature of the two synthetic resin materials to be joined is the same and they are compatible, so the re-synthetic resin material However, when joining different types of synthetic resin materials, since the melting temperatures of the two synthetic resin materials are different and their compatibility is poor,
It is difficult to join resynthetic resin materials. The latter chemical bonding method is equally 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 material of the synthetic resin material, making it difficult to firmly join resynthetic resin materials.

From the above, it goes without saying that in cases of different species,
When joining synthetic resin materials even if they are of the same type,
Many mechanical joining methods are used. A typical example thereof will be explained using a method of joining polypropylene resin and polyethylene resin as shown in FIG.

In FIG. 7, reference numeral 51 is a plate member made of polypropylene resin, and a plate member 52 made of polyethylene resin is placed at the bottom of this plate member 51. Through-holes 53a and 53b are provided at portions opposite to the plate member 51.
is formed. A screw 55 is screwed into the through holes 53a, 53b of both plate members 51, 52 from above with a gasket 54 interposed therebetween, and both plate members 51, 52 are joined.

[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 invention was made to solve the above-mentioned problems, and at least one of the synthetic resin materials to be joined is made transparent to laser light, and between it and the other synthetic resin material, Non-transparent to laser light,
By disposing a sheet-like synthetic resin material mixed with heat-resistant reinforcing fibers and irradiating laser light from the direction of the transparent synthetic resin material, the strength of the re-synthetic resin material can be reduced. The purpose is to easily and firmly join the parts without any problems. '.

Means for Solving Problem c] That is, in the method for joining synthetic resin materials according to the present invention, when joining the same kind of molded resin materials to each other regardless of the force ζ, the synthetic resin At least one of the materials is transparent to laser light, and there is a material between it and the other resin material that is non-transparent to laser light.
A sheet-shaped synthetic resin material mixed with heat-resistant reinforcing fibers is placed, and after the living synthetic resin material is overlaid, a synthetic resin transparent to the laser beam is formed. The laser beam is irradiated from the direction of the material. □ An example of a synthetic resin material that is transparent to laser light is polypropylene resin, and an example of a synthetic resin material that is non-transparent to laser light is carbon black of 0.05 to 50%. Polypropylene resin added in the range of 2.0% by weight, styrene reinforced with glass fibers in the range of 1.0% to 30% by weight, and carbon black added in the range of 0.05 to 2.0% by weight. Examples include acrylonitrile copolymers. Furthermore, examples of the sheet-shaped synthetic resin material that is non-transmissive to laser light include the aforementioned synthetic resin material that is non-transparent to laser light and formed into a sheet shape. These 'synthetic resin materials are a combination of one that is transparent to laser light, one that is non-transparent, and a sheet-like material, or one that is transparent on both sides and a non-transparent material in the middle. It is possible to freely select and join any combination of arranged materials.

In addition, the reinforcing fibers having heat resistance may be those having a melting temperature higher than the melting temperature of the resynthesized resin material used as the base material, such as glass fibers, metal fibers, carbon fibers, etc. can.

Lasers used for joining synthetic resin materials include glass: neodymium laser, YAG = neodymium 3+ laser, ruby laser, helium-neon laser,
Krypton laser, argon laser, N2 laser, N2
Laser etc. can be mentioned.

Furthermore, the wavelength of the laser used when bonding synthetic resin materials needs to be compatible with the synthetic resin materials to be bonded, and this is determined by the absorption spectrum characteristics of the synthetic resin materials. In other words, for the combination of synthetic resin materials to be joined, one is transparent to laser light, and the sheet-shaped synthetic resin material mixed with heat-resistant reinforcing fibers is non-transparent to laser light. In the combination of a polypropylene resin with the same properties, a styrene-acrylonitrile copolymer with the latter properties, and a general resin with carbon black or pigment added as a colorant, Y
AG: oscillation wavelength of neodymium 1+ laser. 1.0
6 μm passes through.

In addition, the output of the lede must be sufficient to melt the synthetic resin material, and when using a YAG: neodymium 1" laser, a suitable value is approximately 5 to 100 W. If it is too high, the synthetic resin material will evaporate and bonding will become impossible, so this must be taken into consideration.

〔Example〕

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

FIG. 1 is a schematic cross-sectional view explaining the method of joining synthetic resin materials according to the present invention, FIG. 2 is an enlarged cross-sectional view of the ellipse of section A in FIG. 1(d), and FIG. 1 shows a cross-sectional view of a laser beam irradiation device used in the method.

First, YAG used in this example: neodymium 1
''The laser beam irradiation device will be explained with reference to FIG.

In FIG. 5, reference numeral 1 denotes a cylindrical body formed from a metal material, and this cylindrical body 1 is attached to an upper case l.
It is divided into two parts, a and lower case 1b, and both cases 1
It is assumed that a and 1b have the same diameter. In addition, YAG
：An optical fiber 2 connected to a neodymium laser oscillator (not shown) is connected □, YAG
: The YAG laser beam M transmitted from the neodymium 3+ laser oscillator is reflected within the core rod 3 of the optical fiber 2 and is incident on the cylindrical body l.

Moreover, the inner part of the cylindrical body l has two optical lenses 4a, 4.
b and 4c are arranged with an interval between them.

That is, the first optical lens 4a is a 1.1 convex lens and is disposed near the lower end of the upper case 1a,
The second optical lens 4b is a convex lens, and is sunk completely into the substantially central portion of the lower case 1b. Similarly to the first optical lens 4a, the J-th optical lens 4c has a diameter of 617 mm, and is disposed near the lower end of the housing case 1b.

Then, the YAG laser beam M inputted into the optical fiber in a dual-power manner becomes a YAG laser beam Ma having a spread angle θ from the incident part of the upper case 1a, and enters the first optical lens 4a. Furthermore, YAG incident on the first optical lens 4a
The laser beam Ma becomes a parallel YAG laser beam Mb and the second
The YAG laser beam Me enters the third optical lens 4b, becomes a spherical YAG laser beam Me that is condensed again at a certain focal point, and then passes through the third optical lens 4c.
incident on . Further, the spherical YAG laser beam Mc that has entered the third optical lens 4c is emitted again as a parallel YAG laser beam Md. And the second optical lens 4
b and the third optical lens 4c, the diameter of the emitted YAG laser beam Md can be changed arbitrarily.

Furthermore, the lower case 1b constituting the cylindrical main body 1 is provided with an irradiation nozzle 5 made of a metal material. This irradiation nozzle 5 has a flange 5a formed at its upper end.
The flange 53 portion is brought into contact with the lower end portion of the lower case 1b and is held by the screwing of the fixing fitting 6. Further, a fourth optical lens 4d is provided near the lower end of the irradiation nozzle 5.
This fourth optical lens 4d is a convex lens like the second optical lens 4b, and the parallel YAG laser beam Md emitted from the third optical lens 4C is directed to the irradiation nozzle 5. The spherical YA'G laser beam M is guided and reaches the fourth optical lens 4d, and is focused again on a certain focal point.
e and is emitted.

Next, the method for joining different types of synthetic resin materials is shown in Figures 1 to 5.
This will be explained according to the diagram.

In (a) to d) of FIG. 1, 21 is a styrene-acrylonitrile copolymer (A S
G), the raw material color of this plate member 21 is black due to the mixing of carbon black,
As shown in FIG. 3, it has the property of being non-transmissive (low transmittance of laser light) for laser light of 1.06 μm or less.

Further, the upper part of the plate member 21 has a thickness in which 20% by weight of glass fibers having a length of 0.5 mm to 3 mm are added as reinforcing fibers having heat resistance, and 0.1% by weight of carbon black is added. Q. A thin plate 22 made of styrene-acrybinitrile copolymer (ASG) in the form of a 5 mm sheet is provided.

This thin plate 22 has a diameter of 1.06μ as shown in FIG.
It has the property of being non-transparent (low transmittance of laser light) to laser light of m or less, and its raw material color is black due to the addition of carbon black.

Moreover, the upper part of the thin plate 22 is made of polypropylene resin (P P
) is provided.

The raw material color of this plate member 23 is milky white, and it has a property of being transparent (high transmittance of laser light) for laser light of 1.06 μm or less, as shown in FIG. ing.

Therefore, when joining the two plate members 21 and 22 made of synthetic resin material set as shown in (a) of Fig. 1, polypropylene is used as shown in (b) and (C) of Fig. 1. The tip of the YAG:Neodymium 3+ laser irradiation nozzle 5 is brought into contact with the upper surface of the resin plate member 23 to apply a load in the direction of arrow B, and the wavelength of 1.06 is emitted from the irradiation nozzle 5.
μm, YAG laser beam M with output of 5 to 100W
irradiate e.

Here, the effect remains the same whether the irradiation nozzle 5 is brought into contact with the plate member 23 or separated from it, and if the non-contact processing characteristic of laser processing is to be utilized, it is better to keep it separated. It is better. However, in this case, heat-resistant glass fibers and carbon black are added to both plate members 21 and 23 and between them, and a styrene-acrylonitrile copolymer that is nasally permeable to laser light is used. so as to keep the thin plate 22 formed into a sheet in close contact with the
For example, it is necessary to take measures such as using a mechanical ramp mechanism.

In addition, when setting the output 5 or IQOW, take into account the power density, which is common knowledge in laser light utilization.
It is important that the plate members 21 and 23 are melted but not evaporated. In this state, the YAG laser beam Me is transmitted due to the relationship between its wavelength and the absorption spectrum of the synthetic resin material.

As a result, as shown in FIG. 1C, the energy of the YAG laser beam Me is accumulated in the thin plate 22 of the styrene-acrylonitrile copolymer containing glass fibers, heating and melting it. As a result, the glass fibers in the thin plate 22 become entangled with the upper surface of the plate member 21 and the lower surface of the plate member 23, and the plate members 21 and 23 are joined via the glass fibers of the thin plate 22.

Thereafter, as shown in FIG. Remove the load. As a result, as shown in FIG. 2, both plate members 21 and 23; the glass fibers 24 of the thin plate 22 enter the melt and harden in an entangled state, and the plate member 23 made of polypropylene resin and the styrene-acrylonitrile copolymer The plate member 21 consisting of the above is firmly joined.

Further, if the plate member 23 is continuously moved along the surface of the plate member 23 while being irradiated with the YAG laser beam Me, the bonding area becomes larger in the direction of movement, and an even stronger bond can be obtained.

Finally, according to this example, the tensile strength was tested by changing the amount of glass fiber added to thin #i22. As shown in Figure 6, the tensile bonding strength due to the anchoring effect, which eliminates the inclusion of glass fibers, was 9.9 kg at the irradiation beat length of the YAC laser beam Me.
f, and when the other glass fiber was mixed at a ratio of 20% by weight, 20 kgf was obtained.

〔Effect of the invention〕

As explained above, in the method for joining synthetic resin materials according to the present invention, at least one synthetic resin material is made transparent to laser light, and there is a gap between the synthetic resin material and the other molded resin material. A sheet-like synthetic resin material containing heat-resistant reinforcing fibers and non-transparent to laser light is provided, and the laser light is irradiated from the direction of the transparent synthetic resin material. , the joining surfaces of the two synthetic resin materials to be joined are heated and melted, and the reinforcing fibers enter these melts and are entangled and joined together, making the re-synthetic resin material even stronger. effective.

In addition, in the present invention, one of the synthetic resin materials to be bonded must be transparent to laser light, but the intermediate synthetic resin material that is non-transparent to laser light must be heat resistant. Since the other synthetic resin material mixed with the reinforcing machine is used, the other synthetic resin material may be any synthetic resin material, and there can be no restrictions on the type of synthetic resin material to be joined. .

In addition, in the present invention, since the resynthetic resin materials are joined by irradiating laser light from one side of the synthetic resin materials, it is easier to join the resynthetic resin materials compared to conventional mechanical joining methods. There are effects 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 joint of the resynthetic resin material, 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 method of joining synthetic resin materials according to the present invention. FIG. 2 is an enlarged cross-sectional view of the ellipse of section A in FIG. 1(d). FIG. 3 shows the results of spectrum analysis of a styrene-acrylonitrile copolymer. Figure 4 shows the results of spectrum analysis of polyethylene resin. FIG. 5 is a sectional view of a laser beam irradiation device used in the bonding method of the present invention. FIG. 6 is a diagram showing the tensile strength depending on the amount of glass fiber added to a thin plate of styrene-acrylonitrile copolymer. FIG. 7 is a schematic cross-sectional view illustrating a conventional method of joining synthetic resin materials. 5------One irradiation nozzle 4d---Fourth optical lens Md, Me---YAG laser beam 21------
Plate member 22 made of styrene-acrylonitrile copolymer...---Thin plate 23 of styrene-acrylonitrile copolymer containing glass fiber---Plate member 2 made of polypropylene resin
4-・----Glass fiber applicant Toyota Motor Corporation 23-7;
Tashigi Toy 1'y+d, Me---YA a Seeb Yu (a) (t)) (0)
Figure 1 (d) Figure 2 Figure 7 Figure 6 One crocodile (41 pull gt) in the cage (50)

Claims (1)

[Claims] When overlapping synthetic resin materials and joining them together,
A sheet in which at least one of the synthetic resin materials is transparent to laser light, and reinforcing fibers that are non-transparent to laser light and have heat resistance are mixed between the two synthetic resin materials. A synthetic resin characterized in that a synthetic resin material of a shape is arranged, and after these three synthetic resin materials are superimposed, a laser beam is irradiated from the direction of the synthetic resin material that is transparent to the laser beam. How to join materials.