JPH05214119A - Method for bonding polyolefinic material - Google Patents

Abstract

PURPOSE:To carry out the adhesive bonding of a polyolefinic material, excellent in bonding reliability with a high accuracy by coating the polyolefinic material with a primer, then superposing another material on the coated polyolefinic material, subsequently irradiating the superposed materials with laser beams and forming firm adhesive bonds in the interface. CONSTITUTION:A polyolefinic material such as PE or PP, assuming black or a dark color and having enhanced absorption of laser beams is coated with an adhesive or successively with a primer and the adhesive and another material such as a glass plate is then superposed on the coated surface and bonded. In the process, after coating the polyolefinic material with the primer, the adhesive or the primer and the adhesive or superposing the other material thereon, the resultant polyolefinic material is irradiated with laser beams such as gaseous carbon dioxide laser beams to form firm adhesive bonds in the interface between the polyolefinic material and the adhesive layer or the primer and the adhesive layer. Thereby, the bonding of the polyolefinic material is carried out.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for adhering a polyolefin material, and more specifically, through a strong adhesive bond at the interface between the polyolefin material formed by laser irradiation and an adhesive layer or a primer and an adhesive layer. High adhesion reliability and precision of polyolefin materials and other materials
It relates to a method capable of (reproducibly) bonding.

[0002]

BACKGROUND OF THE INVENTION Polyolefin materials such as polyethylene (PE), polypropylene (PP), ethylene-propylene-diene terpolymer (EPDM), other polyolefin copolymers or these polyolefin materials. Demand for mixed molded products containing either of these has not been low in various fields from the past, but in the last few years, for the purpose of environmental protection, it is a substitute for recyclable and safer materials. Demand is growing rapidly. However, as a drawback of this polyolefin material, poor adhesion in adhesion or painting has been a problem.

Therefore, conventionally, in order to improve the adhesiveness in the adhesion or coating of the polyolefin material, a method of performing a surface treatment such as a chemical treatment with a strong acid or a strong alkali, a primer treatment, a corona treatment, a reduced pressure plasma treatment, a UV treatment and the like. Has been taken. Each of these methods has its own drawbacks, but especially in the method excluding the low-pressure plasma treatment, the biggest drawback is that the results vary and the reliability after aging is lacking. This is a fatal defect when assuming the joining of automobile parts used for at least 10 years. Therefore, a method with higher accuracy (reproducibility) and higher reliability is desired.

On the other hand, in the low-pressure plasma treatment or the UV treatment under reduced pressure, the reduced-pressure tank itself is an obstacle to practical use. When considering automation, corona treatment, low pressure plasma treatment, UV
High-speed processing in seconds is not possible with physical processing such as processing.

In addition to such a method, there is known a method of improving the adhesiveness by pre-treating the surface of a plastic material using laser irradiation. In this method, for example, a plastic material is irradiated with a laser beam to cause surface shape change, oxidation and / or removal of impurities and obstacles, and then a primer and an adhesive are sequentially applied, and then another material is applied to the applied surface. Is a method of overlapping and adhering
(It is also known to apply laser irradiation to paint). However, this method merely causes some change in the physical state on the surface of the plastic material, which only physically bonds the primer and the adhesive layer, which has been desired in the past. At present, it has not been possible to achieve highly accurate and reliable adhesive force development. Particularly by this method, it was difficult to improve the adhesiveness to a low-polarity polyolefin material.

[0006] In laser processing, which is often used for welding and cutting various plastic materials, there have been few reports about surface modification of plastics, and the reason is that energy control is difficult. In addition, when a functional group is introduced by oxidation or so-called chemical effect, a too expensive special device such as an excimer laser is required. Therefore, although the surface modification of polyolefin materials can be expected, the use of UV laser is not practical. On the other hand, it is possible to use a general thermal laser such as a carbon dioxide laser or a YAG laser, and pay close attention to energy adjustment to change the shape of the surface and remove impurities and obstacles. As an example of its application, there is a technology to increase the strength by applying an adhesive after irradiating a glass fiber reinforced plastic with laser [Yoshihiko Mukai, Arata Nishimura "Joytech,
September 1989 "(p. 50-55)," Laser pretreatment in adhesive bonding of FRP "]. However, it is considered very difficult to improve the adhesive performance by modifying the surface pretreatment of the polyolefin material by such laser irradiation.
This is because no chemical effect can be expected.

[0007]

Therefore, the present inventors have
As a result of intensive research on improving the adhesive strength of polyolefin materials by such laser irradiation, laser irradiation was adopted at an appropriate time after application of a primer or an adhesive instead of the surface pretreatment by laser irradiation that has been conventionally studied. It has been found that a strong adhesive bond can be formed at the interface between the polyolefin material and the adhesive layer or the primer layer and the adhesive layer, so that the desired highly accurate and reliable adhesive force can be developed. The present invention has been completed.

That is, according to the present invention, in an adhesion method using one or both of adherends as a polyolefin material, an adhesive agent is applied to the polyolefin material, or a primer and an adhesive agent are applied in sequence, and then the applied surface is applied. When the other materials are superposed and adhered to each other, laser irradiation is performed after applying the primer of the polyolefin material or after applying the adhesive, or after applying the primer and the adhesive, or after superposing the other materials, and the polyolefin material Provided is a method of adhering a polyolefin material, which comprises forming a strong adhesive bond at the interface between the adhesive layer or the primer and the adhesive layer.

Polyolefin materials targeted by the present invention include polyethylene, polypropylene, ethylene-propylene-diene terpolymers (EPDM), other polyolefin copolymers or blended moldings containing any of these polyolefin materials. There are no restrictions on the type. Further, in order to enhance absorption of the laser beam, those exhibiting black or dark color are preferable.

In the present invention, as a primer which can be used to improve the adhesiveness with a polyolefin material, an isocyanate type or a silane type of a type which transmits a laser beam, for example, an isocyanate type, manufactured by Sunstar Giken Co., Ltd. Primer PP2 ”.
The primer coating thickness may normally be set in the range of 0.1 to 50 μm.

The adhesive used in the present invention is not particularly limited as long as it is an ordinary adhesive. For example, various thermosetting or thermoplastic adhesives such as epoxy, urethane or silicone adhesives, synthetic rubber adhesives, synthetic adhesives are used. A resin adhesive may be used. In addition, apply the adhesive directly to the polyolefin material,
When laser irradiation is performed thereafter, the adhesive is preferably one that transmits a laser beam. The coating thickness of the adhesive may be set so that the thickness of the adhesive layer described later is usually 0.5 to 10 mm. The adhesive of the present invention also includes a sealing material.

Laser used in the present invention [LASER: Lig
ht Amplification by Stimulated Emission of Radi
(abbreviation of ation), any laser can be selected from infrared rays to visible rays, but especially in terms of transparency and cost, for example, YAG laser (wavelength 1.06μ)
Is preferred.

A method of bonding one or both of the adherends according to the present invention with a polyolefin material is a method of bonding a polyolefin material and an adhesive layer or a primer and an adhesive layer (hereinafter, these layers are bonded together by laser irradiation). It is characterized by forming a strong adhesive bond at the interface with a layer) and can be carried out according to the following procedure. (A) When applying an adhesive to a polyolefin material, or applying a primer and an adhesive in sequence, after applying a laser after applying a primer or applying an adhesive or applying a primer and an adhesive, the applied surface is Material of
[For example, polyolefin materials (primer, adhesive application → laser irradiation as above), plastic materials, metal materials, wood materials, ceramics, glass, etc.) should be superposed and adhered. Or (B) the application of the adhesive, or the application of the primer and the adhesive, followed by superimposing other materials, and then irradiating with a laser for adhesion. In this case, the other material must be a material that transmits a laser beam (for example, a glass plate). In addition, the application of the adhesive is not limited to the polyolefin material, but it is applied to the other adherend material, and is superposed.
It is also possible to perform laser irradiation for adhesion.

In any of the above procedures (A) and (B), although not certain, i) uneven shape change at the interface between the polyolefin material and the adhesive layer by laser irradiation, ii) adhesion with the polyolefin material Melt mixing of layers, and / or
Or iii) It is presumed that a strong adhesive bond is formed by a phenomenon such as formation of a chemical reaction product or a chemical bonding reaction part between the polyolefin material and the adhesive layer.

[0015]

EFFECTS OF THE INVENTION According to the method of the present invention having the above-mentioned structure, highly accurate (reproducible) and highly reliable adhesive force can be exhibited, and the adhesive property does not deteriorate due to aging. In addition, 1) no decompression chime bar is required 2) High-speed processing in units of seconds is possible 3) Purpose is achieved by using a relatively inexpensive laser for welding applications such as YAG laser It is very limited, and the combination of defocus and mirrors allows for a wide range of treatments that lasers are not good at. 5) When laser irradiation is performed by the method of the present invention, an additional effect such as an effect of improving adhesiveness can be achieved for a long period of about 7 days immediately after irradiation. It is also possible to utilize the laser irradiation after applying the primer or the adhesive of the method of the present invention to develop the effect of improving the adhesive strength to the polyolefin material in coating. For example, it is possible to improve the adhesiveness of the coating material to the polyolefin material by performing undercoating or intermediate coating on the polyolefin material, laser irradiation, and then topcoating.

[0016]

EXAMPLES Next, the present invention will be described more specifically with reference to examples (including comparative examples). Example 1 A black polyethylene material is used as an isocyanate primer
(Sun Star Giken Co., Ltd., Primer PP2) is applied by dipping, and after 10 minutes, a YAG laser (HASU LASER LAYER, LAY75) is used to defocus the laser beam to a diameter of 10 mm (light source voltage 0.5 KV, After performing pulse duration 0.5 msec, 3 pulses), two-component epoxy adhesive (XB3179 / XB3180 manufactured by Ciba-Geigy)
Or two-component urethane adhesive (Sunstar Giken Co., Ltd.)
(Penguin seal 571A) is applied so that the adhesive layer thickness is 3 mm, and then another material (coated steel sheet coated with isocyanate-based primer) is adhered to the polyethylene material so that the tip length is 5 mm, respectively. To do. Two types of aging conditions for the obtained adhesive material: under heating atmosphere
(80 ℃ × 30 minutes or 70 ℃ × 30 minutes) or water immersion
After being subjected to (30 days), the sample is subjected to a shear test with a tensile speed of 50 mm / sec, and the shear strength (N / cm ² ) is measured (twice for each sample). The results are shown in Table 1 below (Note that, as a comparative example, the results in the case of no primer treatment or no laser irradiation are also shown).

[0017]

[Table 1] From the results of Table 1, laser irradiation (3
In both the case of applying the pulse) and the case of no laser irradiation for the primer treatment, the interface of the adhesive was destroyed and no improvement in the adhesiveness was observed. When the laser-irradiated surface was separately treated with a primer, all were AF.

Example 2 A black EPDM material and a silane-based primer (Shin-Etsu Chemical Co., Ltd.)
Co., Ltd., silane coupling agent KBM-603 / KBM
-403 (1: 1) mixture) or an isocyanate primer (primer PP2) was applied by a dipping method, and YAG laser irradiation (provided that 1 or 5 was used under the same conditions as in Example 1).
Pulse), and then a one-component silicone adhesive (Penguin Seal 2505, manufactured by Sunstar Giken Co., Ltd.) was applied so that the adhesive layer had a thickness of 3 mm. The materials are overlapped and bonded. 1 adhesive material obtained
After being left for 68 hours at room temperature or subjected to aging conditions of immersion in water (30 days), the sample is subjected to the same shearing test as in Example 1. The shear strength (N / cm ² ) is shown in Table 2 below (Note that, as a comparative example, the results in the case of no primer treatment and no laser irradiation are also shown).

[0019]

[Table 2]

Example 3 Isocyanate-based primer on black polyethylene material
(Primer PP2) was applied by a dipping method and irradiated with YAG laser under the same conditions as in Example 1 (however, with one pulse), and then a one-component urethane adhesive (Sunstar Giken Co., Ltd.)
Then, a penguin seal 551) is applied so that the adhesive layer has a thickness of 3 mm, and then other materials are superposed and adhered in the same manner as in Example 1. The resulting adhesive material is subjected to the same aging conditions as in Example 2, and then subjected to the same shear test as in Example 1. The shear strength (N / cm ² ) is shown in Table 3 below (as a comparative example, the results of no primer treatment and no laser irradiation are also shown). Furthermore, a corona device (made by Arcotech, Ty
The results when the surface pretreatment is performed by corona treatment (30 seconds) using p-mini) are also shown.

[0021]

[Table 3]

Example 4 Isocyanate-based primer on black polyethylene material
(Primer PP2) is applied by a dipping method, and then a one-pack type silicone adhesive (penguin seal 2505) is applied so that the adhesive layer has a thickness of 5 mm, and then a glass plate having a thickness of 5 mm is laminated in the same manner as in Example 1. After combining, YAG laser irradiation (however, with 5 pulses) is performed under the same conditions as in Example 1 to bond. The resulting adhesive material was subjected to the same shearing test as in Example 1 without subjecting it to aging conditions, and the shear strength (N / cm ² )
Is shown in Table 4 below (Note that the results in the case of no laser irradiation are also shown as a comparative example).

[Table 4] No laser irradiation: * AF, * AF irradiation: 50.5AF (60%) (5 pulses) 62.8AF (50%) Note) Refer to Table 1 for AF and * in Table 4.

The laser irradiation in Examples 1 to 4 was evaluated by changing the irradiation angle from 90 ° to 30 ° and the defocus from 5 mm to 10 mm in diameter. Good adhesion was exhibited without any problem. , The ease of energy adjustment and the degree of freedom of the shape of the adherend were confirmed. For wide area processing, a combination of a half mirror and a mirror was an easy solution. After applying the primer, the time until laser irradiation was evaluated from 5 minutes to 72 hours, but no variation in the results was observed and good adhesiveness was confirmed. Furthermore, the adherable time after laser irradiation was 7 days immediately after laser irradiation. It was also confirmed that the adhesiveness-improving effect was obtained even when left for a long time as described above.

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[Procedure amendment]

[Submission date] February 18, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

The laser irradiation in Examples 1 to 4 was evaluated by changing the irradiation angle from 90 ° to 30 ° and the defocus from 5 mm to 10 mm in diameter. Good adhesion was exhibited without any problem. , The ease of energy adjustment and the degree of freedom of the shape of the adherend were confirmed. For wide area processing, a combination of a half mirror and a mirror was an easy solution. After applying the primer, the time until laser irradiation was evaluated from 5 minutes to 72 hours, but no variation in the results was observed and good adhesiveness was confirmed. Furthermore, the adherable time after laser irradiation was 7 days immediately after laser irradiation. It was also confirmed that the adhesiveness-improving effect was obtained even when left for a long time as described above. Example 5 A one-component silicone adhesive (penguin seal 2505) was applied to a black polyethylene material so as to have a thickness of 3 mm, and then a glass plate having a thickness of 5 mm was pressed, and a diameter of 6 mm was applied on the polyethylene material. Y defocused so that
Irradiate with AG laser (light source voltage 0.5 KV, pulse duration 0.5 msec, 1 or 3 pulses) to bond. The resulting adhesive material was subjected to the same shearing test as in Example 1 without subjecting it to aging conditions, and the shear strength (N / cm ² ) is shown in Table 5 below (note that in the case of no laser irradiation as a comparative example). The results are also shown).

[Table 5] No laser irradiation: 3 or less AF irradiation: 1 pulse 15AF (50%) 3 pulses 59CF Note) Refer to Table 1 for AF and CF in Table 5.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Go Nagata 7-1 Akita-cho, Takatsuki-shi, Osaka Sunstar Giken Co., Ltd.

Claims (5)

[Claims] 1. A method for adhering one or both of adherends to a polyolefin material, wherein an adhesive is applied to the polyolefin material, or a primer and an adhesive are applied sequentially, and then another material is applied to the applied surface. The layers of the polyolefin material and the adhesive are laminated by applying laser irradiation after applying the primer or adhesive of the polyolefin material, or after applying the primer and the adhesive, or after overlapping other materials. Alternatively, a method for adhering a polyolefin material, which comprises forming a strong adhesive bond at the interface between the primer and the adhesive layer. 2. The polyolefin material comprises polyethylene, polypropylene, ethylene-propylene-diene terpolymers, other polyolefin copolymers or any of these polyolefin materials which are black or dark and have enhanced absorption of laser light. The bonding method according to claim 1, which is a mixed molded body. 3. The bonding method according to claim 1, wherein laser irradiation is performed after applying a primer to the polyolefin material. 4. The bonding method according to claim 1, wherein the laser irradiation is performed after the other materials are superposed, and in this case, the other material and the adhesive transmit the laser beam. 5. The bonding method according to claim 4, wherein the other material is a glass plate.