JPH11170374A - Bonding method of synthetic resin molding member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to produce a molding member having a monocoque construction by a method wherein a plurality of molding members are integrally bonded together by thermal fusion through a bonding layer, which includes an un- molded synthetic resin material the same as that of a plurality of the molding members and is formed on at least one of bonding surfaces opposing to each of the molding members. SOLUTION: A plurality of molding members 1 made of the same synthetic resin material as each other are molded at a certain molding temperature. A bonding layer 2a, the solvent of which includes an un-molded synthetic resin material 2 having the same material as that of the molding material 1, is formed on at least one of bonding surfaces opposing to each other of a plurality of the molding members 1. After that, the bonding layer 2a is heated under the temperature condition being lower than a molding temperature so as to evaporate the solvent in the bonding layer. Next, by heating a plurality of the molding members 1 through the bonding layer 2a up to the temperature exceeding its molding temperature, the members are integrally bonded together. In order to bondingly fix complicated and fine molding members 1, an adhesive prepared by dissolving the same material, of which a molding is molded, in a solvent, is coated as the bonding layer 2a so as to opposedly urge the members 1 through the layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for bonding a synthetic resin molded member.

[0002]

2. Description of the Related Art Heretofore, in the production of a synthetic resin molded member having a fine internal structure, these have been divided into a plurality of parts, molded, and then integrated by bonding. Hereinafter, an ink jet head used in an ink jet printer will be described as an example. The ink jet head has a discharge volume of about 30 pl to 100 p for one drop of ink.
Since a very small amount of 1 is ejected, the ink chamber that holds the ink liquid amount is necessarily a small liquid chamber.

Conventionally, an ink jet head nozzle portion including an ink chamber is composed of a vibrating member and a plurality of pieces such as a molding member having a nozzle and an ink chamber, each of which is formed by injection molding and bonded by an adhesive. It was produced by.

[0004] Further, a method of bonding with a dope cement in which the same material as a molded member is dissolved in a solvent as an adhesive has been conventionally considered. However, in this method, since a small amount of solvent is left at the time of bonding and the solvent is volatilized after the bonding is completed, bubbles created when the solvent is volatilized in the adhesive layer always occur and significantly impair sealability, so ink jet printing It is not suitable for an application such as a head which needs to secure a seal with a width of 80 microns. Further, this method has a weak point in strength and has a problem.

[0005]

In the conventional resin molding bonding technique, the resin molding members are bonded by using an adhesive (a material different from the material of the molding) manufactured by a specialized maker. Was common. However,
When an integrated head is made by bonding and fixing two or more pieces with a complicated and fine structure like an ink jet head, the characteristics of the adhesive layer part differ from the characteristics of the resin molded product, With respect to the adhesive strength and accuracy, there was a high possibility that various problems such as peeling, difference in thermal expansion, adhesive residue, unevenness, and protrusion would occur.

[0006] Alternatively, as a typical method of finely bonding a resin molded product, sheet bonding using a sheet-like adhesive may be performed. However, a problem such as ink resistance may occur in the sheet adhesive. there were.

On the other hand, conventional integral molding (monocoque structure)
In general, a molding method typified by injection molding or blow molding is used for the head, but it cannot be applied to a case where a fine and complicated head is manufactured.

[0008] In the case of a molded member obtained by bonding a plurality of resin molded products and having a fine and complicated hermetic structure, it is essential that the adhesive layer portion has a complete hermetic structure. . Therefore, in the present invention, a molded member having a monocoque structure is manufactured by eliminating the above-mentioned disadvantages caused by the adhesion of the resin molded products to each other and by giving the adhesive layer the same physical properties as when integrally molded. The task is to

[0009]

According to the present invention, there is provided a method of bonding a synthetic resin member, comprising: forming a plurality of molded members made of the same synthetic resin material at a constant molding temperature; An adhesive layer containing an unformed synthetic resin material is formed on at least one of the opposed adhesive surfaces of the plurality of molded members, and the plurality of molded members are heated and melted to a molding temperature via the adhesive layer to be integrally bonded. It is in.

In the above bonding method, it is preferable that the bonding layer is adhered to the bonding surface by electrostatic coating, and the plurality of formed members and the bonding layer are bonded by heating and melting at a forming temperature. Alternatively, the adhesive layer may be formed on the adhesive surface by spin coating or printing. Alternatively, the adhesive layer may be formed into a sheet and attached to the adhesive surface.

[0011] Another method of bonding a synthetic resin member according to the present invention, which solves the above-mentioned problems, is to form a plurality of molded members made of the same synthetic resin material at a constant molding temperature, and to form an unformed synthetic material of the same quality as these molded members. An adhesive layer containing a resin material in a solvent is formed on at least one of the opposing adhesive surfaces of the plurality of molded members, and the adhesive layer is heated at a temperature condition equal to or lower than the molding temperature to evaporate the solvent in the adhesive layer. It is an object of the present invention to heat and melt a plurality of molded members to a temperature exceeding a molding temperature via an adhesive layer and integrally bond them.

In the above-mentioned bonding method, the solvent may have volatility. Further, in the bonding method described above, it is preferable that a plurality of molded members are molded at a temperature equal to or lower than the crosslinking completion temperature, and the synthetic resin in the solvent is made a material before the completion of the crosslinking.

In the above-mentioned bonding method, the plurality of molded members bonded together may be heated to a crosslinking temperature and cured.

Preferably, an epoxy resin or a phenol resin is used as the synthetic resin, and the molded member molded at the molding temperature and the adhesive layer are heat-bonded.

In the present invention, the plurality of molded members are
A vibration member of the ink jet head for transmitting the vibration of the piezoelectric element to the pressure chamber, and a forming member of the ink jet head in which a plurality of nozzles and a plurality of pressure chambers corresponding to the nozzles are formed. At this time, a plurality of molded members of the phenol resin, which have been completely bonded, may be baked in an inert gas to form amorphous carbon, thereby forming a monocoque structure as a whole.

The adhesive used in the present invention is made of the same material as the molded member, directly or in a solvent by mixing, dispersing,
It melts and forms on the bonding surface in various ways. The same effect can be obtained by replacing this solvent with a conventional liquid adhesive (a material different from the molded product).

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the drawings for embodiments of an ink jet head.

FIG. 1 shows a nozzle-side forming member (hereinafter referred to as a nozzle-side forming member) 1 of an ink jet head.
FIG. 2 shows a forming member 2 on the ink chamber side (hereinafter, referred to as an ink chamber forming member). Both molding materials are made of a synthetic resin material.

FIG. 3 shows a nozzle-side molding member 1 and an ink-chamber-side molding member 2 of an ink-jet head bonded to each other.

When the complicated and fine molded member prepared in FIGS. 1 and 2 is bonded and fixed as shown in FIG. 3, the adhesive used for the bonding is made of the same material as that used for forming the molded product. The materials are mixed or dissolved with a solvent (using various kinds of optimum solvents depending on the material of the resin), and the adhesive is applied as the adhesive layers 1a and 2a, and then the substrates are pressed against each other to complete the bonding.

In this example, a phenol resin was used as an example for each molded member. The molding temperature of this resin is 10 degrees Celsius
0-110 degrees, the crosslinking temperature is 180 degrees. The adhesive layer
Using MEK (methyl-ethyl-ketone) or alcohol (for example, isopropyl alcohol, acetone, monoethanolamine, etc.) as a solvent, mixing or dissolving the unmolded powder of the present resin, applying it to the bonding surface, and then drying The solvent is completely evaporated in the process. At this time, a thin skin of the adhesive layer on which the crosslinking has not progressed remains on the adhesive surface. Air bubbles are generated in the adhesive layer, leaving small holes. However, when the members are assembled and then heated under pressure, the unmolded resin melts to enable uniform and no gap bonding. In the case of a phenol resin, since the molding temperature is 100 to 110 degrees, it is heated to about 120 degrees to perform melt bonding.

The molding member 1 on the nozzle side and the molding member 2 on the ink chamber side have not been melted since they have been heated to the molding temperature once, but the adhesive surface is activated due to the heat and good adhesion is possible, and the sealing property is satisfactory. Is obtained.

The method of applying an appropriate amount of the adhesive is conventionally known to be performed by a method such as spin coating, silk printing, transfer, powder coating, etc., and therefore, it is possible to appropriately use the method. As a special method, a low-temperature molding into a sheet can be used as an adhesive.

In the bonding of the present invention, the margin of the synthetic resin molded member is 50 μm to 1 μm at the minimum part of the partition wall of the ink chamber 2.
The adhesive is very narrow, about
When it is applied accurately to about m to 15 μm, a desired adhesive strength can be obtained without excess adhesive protruding.

Also, as a bonding method, no solvent is used,
The same material as the material of the molding member is pulverized to fine particles,
The powder may be adhered to the bonding surface by using the principle of electrostatic coating, and then may be bonded by heating, pressing and melting. The adhesive layer is spin coating,
It can be attached by printing, forming into a sheet shape, or the like.

By activating the adhesive surface to be coated with the adhesive layer by plasma asher or chemical treatment, it is possible to realize stronger adhesion.

If the temperature is further increased from the molding temperature after the bonding is completed, the crosslinking is sufficiently advanced to obtain a more chemically stable structure. In the case of this phenol resin, 18
When heated to 0 ° C, crosslinking proceeds sufficiently simultaneously for both the bonded portion and the molded member, resulting in a stable molecular structure. In addition to this, an epoxy resin or other thermosetting resin, a liquid crystal polymer, or the like may be used as the resin.

According to the present invention, a monocoque structure head made of an amorphous carbon material, which is a more stable material, can be realized. When producing an amorphous carbon head, the above-mentioned bonded resin molded member is put into a furnace to be fired, and is fired in an inert gas atmosphere for 1000 hours.
If performed at around ℃, all of the film including the adhesive layer becomes amorphous. Therefore, it is possible to produce an amorphous carbon head having a monocoque structure having a very good performance that the adhesive layer can sufficiently withstand the ink.

FIG. 4 shows an ink chamber manufactured by the above-described manufacturing method, in which an actuator 3 of a piezoelectric element, a power supply circuit 4 for driving the actuator 3, an ink channel 6 as a holder, an ink tube connector and a filter 7 are provided. And the like, and shows a state of being assembled to the ink jet head.

FIG. 5 schematically illustrates the relationship between the progress of the crosslinking of the material, that is, the temperature when the present invention, that is, a phenol resin is used as the synthetic resin material of the molding member.

The resin pellets in which the crosslinking has not progressed before molding are at the point A (70 to 90 degrees Celsius) below the molding temperature.
Heat is applied to this to form a molding temperature point C (100 to 120 degrees Celsius).
(Degrees) and softened at point B (120-140 degrees Celsius) to form a gel before molding the molded member.

Even after the completion of molding, it can be heated and solidified to obtain a solid state in which crosslinking has progressed to some extent. The above-mentioned bonding method is applied to this pair of molded members, and then the bonding layer is heated and pressurized. At a point around point B, the bonding layer becomes a gel or a liquid, and has a crosslinking temperature D (170 to 250 degrees Celsius).
By heating beyond (degree), the cross-linking of the non-cross-linked portions on both sides of the bonding surface of the forming member in contact therewith sufficiently proceeds, and the pair of forming members are integrally bonded as a single material.

Even if the adhesive layer adheres to an open part, not to the adhesive surface, crosslinking proceeds at that part and it is merely integrated with the surface of the molded member, so that it becomes foreign matter or obstructed. It never happens.

As described above, according to the present invention, it is possible to improve the situation in which the desired performance cannot be obtained because the adhesive has been used with a different material from the molding member. It has become possible to achieve a sufficiently satisfactory strength and airtightness in the same manner as in the state described above.

The ink jet head has been described above as an example of the present invention. However, this technique has versatility and can be applied to other technical fields. The same applies to the case of using other resins for injection molding, such as thermoplastic resins (PET, PBT, PC, ABS, AS, etc.).

[0036]

According to the structure of the present invention, since the resin molded member and the adhesive layer are made of the same material, they can be finished in the same manner as an integrally molded product. Therefore, a molded member having the same characteristics as those of integral molding can be obtained even with a complicated shape having a hollow portion on the inside that could not be industrially formed by conventional molding. Therefore, for example, in an inkjet head,
Since the whole is composed of a single chemically stable material, even if a liquid or ink that is chemically active and is likely to be contaminated or eroded is stored inside the component, it will not be attacked by it. .

Further, even when the temperature and humidity of the environment change and the material expands and contracts, stress due to the difference in the expansion coefficient is hardly generated from the case where the entire material is a single material, and the reliability is high. Therefore, the present invention can be applied to a head configuration for a solid ink handled at a high temperature.

Since the number of parts and man-hours are small as a whole, the potential for work failure and operation failure is reduced, and the reliability and the life are extended. In addition, since the number of parts and man-hours are small, inexpensive production is possible, and multi-nozzles are easily formed, so that it is easy to improve performance such as high speed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a molding member on the nozzle side of an inkjet head according to the present invention.

FIG. 2 is a cross-sectional view of a molding member on the ink chamber side of the inkjet head of the present invention.

FIG. 3 is a sectional view when the molded members of FIGS. 1 and 2 are adhered.

FIG. 4 is a cross-sectional view of an inkjet head assembly.

FIG. 5 is a graph showing the relationship between the temperature of a material used as a molding member and the temperature of the material used.

[Explanation of symbols]

Reference numerals 1 and 2 indicate resin molded members, 1a and 2a indicate adhesive layers, 3 indicates an actuator, 4 indicates an electrode circuit, 6 indicates an ink flow path, and 7 indicates a filter.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 63:00 (72) Inventor Jun Nagata 1060 Takeda, Hitachinaka-shi, Ibaraki Pref. Hitachi Koki Co., Ltd.

Claims (11)

[Claims] 1. A plurality of molded members made of the same synthetic resin material are molded at a constant molding temperature, and an adhesive layer containing an unmolded synthetic resin material of the same quality as the molded members is bonded to the plurality of molded members in opposition to each other. A method for bonding a synthetic resin molded member, comprising: forming the plurality of molded members on at least one of the surfaces; heating and melting the plurality of molded members to a molding temperature via an adhesive layer; 2. A synthetic resin molded member according to claim 1, wherein said adhesive layer is adhered to an adhesive surface by electrostatic coating, and said plurality of molded members and said adhesive layer are heated and melted at a molding temperature to be adhered. Bonding method. 3. The method according to claim 1, wherein the adhesive layer is formed on an adhesive surface by spin coating or printing. 4. A method for bonding a synthetic resin molded member according to claim 1, wherein the bonding layer is formed into a sheet and adhered to the bonding surface. 5. A plurality of molded members made of the same synthetic resin material are molded at a constant molding temperature, and an adhesive layer containing an unmolded synthetic resin material of the same quality as the molded members in a solvent is formed on the plurality of molded members. Formed on at least one of the opposing adhesive surfaces, the adhesive layer is heated at a temperature condition equal to or lower than the molding temperature to evaporate the solvent in the adhesive layer, and the plurality of molded members are heated to a temperature exceeding the molding temperature via the adhesive layer. A method for bonding a synthetic resin molded member, wherein the bonding is performed by heating and melting. 6. A method according to claim 5, wherein said solvent has volatility. 7. The method for bonding synthetic resin molded members according to claim 5, wherein a plurality of molded members are molded at a temperature equal to or lower than a crosslinking completion temperature, and the synthetic resin in the solvent is used as a material before the completion of crosslinking. . 8. The method for bonding synthetic resin molded members according to claim 1, wherein a plurality of molded members bonded together are heated to a crosslinking temperature and cured. 9. The bonding of a synthetic resin molded member according to claim 1, wherein a molded member molded at a molding temperature using a phenol resin or an epoxy resin as a synthetic resin is bonded by heating. Method. 10. The ink jet head according to claim 1, wherein said plurality of molding members are a vibration member of an ink jet head for transmitting vibration of a piezoelectric element to a pressure chamber, a plurality of nozzles, and a plurality of pressure chambers corresponding to said nozzles. A method for bonding a synthetic resin molded member, characterized in that the molded member is a molded member of an ink jet head on which is formed. 11. A method of bonding a synthetic resin molded member according to claim 10, wherein the plurality of molded members that have been bonded are fired in an inert gas to form amorphous carbon, thereby forming a monocoque structure as a whole.