JP2009272341A - Coating processing method for magnet molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating processing method for a magnet molding, which excellently bonds the magnet molding to an adherend using a cyanoacrylate-based adhesive without performing coating processing on a primer for adhesion reinforcement during bonding processing for the adherend. <P>SOLUTION: When the coating processing is carried out by coating the magnet molding, bonded and fixed to the opposite-side adherend with the cyanoacrylate-based adhesive, with a liquid of a resin paint composition, an adhesion-curing accelerator which contains a Cu component and generates Cu ions in the liquid of the paint composition of the resin is in advance added to the liquid of the resin paint composition and the magnet molding is coated with the resin paint composition containing Cu ions to achieve the coating processing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for coating a magnet molded body in which resin molding is performed on the magnet molded body, and more particularly to a coating processing method capable of imparting good adhesiveness when adhesively fixing to a mating adherend later. .

  For example, rare earth iron magnets having excellent magnet characteristics have been used in place of ferrite magnets for small high-performance motors such as mobile phone vibration motors and lens focus stepping motors.

  These rare earth iron-based magnets are more susceptible to rust when placed in a high temperature and high humidity environment than ferrite magnets. Therefore, these rare earth iron-based magnets are coated with resin for the purpose of rust prevention, usually epoxy. Used with resin coating.

Thus, the magnet molded body to which antirust coating was given is assembled | attached and fixed to the case, shaft, etc. of a motor.
Conventionally, a cyanoacrylate-based adhesive, particularly a UV curable anaerobic cyanoacrylate-based adhesive is suitably used as the adhesive at that time.
This cyanoacrylate adhesive has a feature that it can be bonded instantaneously after being bonded with one liquid.

  The reason why the cyanoacrylate adhesive instantly exhibits the adhesive function in this way is that cyanoacrylate has two strongly active functional groups, ie, an electron-withdrawing cyano group and a carbonyl group. The cyanoacrylate monomer starts anionic polymerization using water as an initiator, and the polymerization progresses rapidly to bond and cure.

  In addition, cyanoacrylate adhesives with UV curable and anaerobic adhesive functions are easily polymerized and cured by bonding the magnet molded body to the adherend at the adhesive surface and shutting off the air. There is no need for processing, and the process is simple, and even if the adhesive is applied in many ways and the adhesive protrudes from the joint surface, the protruding portion can be polymerized and cured by UV (ultraviolet) irradiation. (At this time, the polymerization proceeds by radical reaction), and it is necessary to wipe off or wash and remove the adhesive that remains unreacted in the liquid state to cause trouble later. Has no advantage.

  However, this cyanoacrylate adhesive, on the other hand, has the drawback of poor adhesion to the resin, so rust is not a major problem as with conventional ferrite magnets. About what can be fixed, it can be used as an effective adhesive as it is, but it is easy to generate rust like the rare earth iron magnets as mentioned above, and it is used after applying resin coating for rust prevention However, there is a problem that it is difficult to firmly bond and fix the magnet molded body to the other-side adherend due to the resin coating formed on the surface.

In such a case, generally considered as a countermeasure is to apply a primer solution as an adhesion curing accelerator as a base treatment agent to one of the joint surfaces of the magnet compact and the other-side adherend, In this method, the adhesion reaction is promoted by the primer component.
In that case, what contains Cu ion for said cyanoacrylate adhesive is used as an effective primer.

  Actually, as shown in FIG. 3, the present inventors apply the primer 18A solution to the resin-coated film 12A previously applied to the magnet molded body 10A, and in that state, apply cyanoacrylate to the adherend 14A. When the adhesive 16A was applied and the two were adhered, it was confirmed that the adhesive strength was increased as compared with the case where the primer 18A was not directly applied but the adhesive was directly adhered.

  As described above, the following patent document 1 discloses that a primer is applied to one of the joint surfaces when the magnet molded body is resin-coated and the resin-coated magnet molded body and the adherend are bonded. Has been.

However, for example, a magnet used for a small motor such as a vibration motor or a lens focus stepping motor used in the above-described mobile phone is, for example, an extremely small ring magnet having an outer diameter of about φ2 mm or a segment type magnet having a width of about 2 mm ( This is a circular arc magnet with a predetermined width in the circumferential direction in which the ring is divided into a plurality of parts in the circumferential direction. It is difficult to automate, and the actual situation is that it is performed manually, and the adhesion of the primer to the magnet molded body or the other side of the adherend is performed manually in an independent process. It is extremely difficult.
In addition to the fact that it is difficult to manually apply a primer to such an extremely small magnet compact, the primer is manually applied to each of a large number of magnet compacts. This is not practical from the viewpoint of work, and even if a primer is applied to the narrow inner diameter side of the magnet molded body, the applied state may be excessively applied for certain things, or conversely In some cases, it may not be applied, resulting in a large variation in the adhesive strength of the magnet compact.
Moreover, if the primer application is performed in a separate step, the number of steps increases and the cost becomes high.
Therefore, the countermeasure by such a method cannot actually be adopted.

In addition, the following patent document 2, patent document 3, patent document 4, patent document 5 etc. point out that there exists a problem in apply | coating the primer liquid as an adhesion hardening accelerator as a base treatment for adhesion reinforcement. ing.
The inventions disclosed in these patent documents are intended to solve the problem. However, all of those disclosed in these patent documents are different from the present invention in the solving means.

JP-A-6-302426 JP 2002-158105 A JP 2006-289610 A JP 2006-156787 A JP 2000-312039 A

  The present invention is based on the circumstances as described above, and it is possible to satisfactorily attach a magnet molded body using a cyanoacrylate adhesive without applying a primer for reinforcing adhesion during the adhesion treatment with the adherend. The object of the present invention is to provide a method of coating a magnet molded body that can be bonded to a material.

  Thus, according to the first aspect of the present invention, there is provided a magnet molded body in which a liquid of a resin coating composition is applied to a magnet molded body that is bonded and fixed to a mating adherend with a cyanoacrylate adhesive. A coating treatment method comprising a Cu component, and an adhesion hardening accelerator that generates Cu ions in the resin coating composition liquid is added in advance to the resin coating composition liquid. A liquid of a resin coating composition is applied to the magnet molded body and subjected to a coating treatment.

  According to a second aspect of the present invention, there is provided the curing accelerator according to the first aspect, wherein the Cu ion has a concentration in the range of 2000 to 20000 ppm based on the solid content of the resin paint in the liquid of the resin paint composition. Is added.

Effects and effects of the invention

  As described above, in the present invention, an adhesion hardening accelerator containing a Cu component and generating Cu ions in a liquid of a resin coating composition is previously added to the liquid of the resin coating composition, and a magnet is formed using this. The molded body is to be painted.

  In other words, a primer previously applied as a base treatment agent on one of the joint surfaces of the magnet molded body and the adherend to enhance adhesion is previously applied prior to the coating treatment of the magnet molded body. In addition to applying the resin coating to the surface of the magnet molded body, at the same time, the resin coating film contains an adhesion hardening accelerator at the same time. It is.

FIG. 1 shows a conceptual diagram thereof.
In the figure, reference numeral 10 denotes a magnet molded body, 12 denotes a resin-coated film applied to the surface, and 14 denotes a mating adherend.
As shown in the drawing, in the present invention, after the resin coating is applied to the magnet molded body 10, the substrate 14 and the resin coating film are not separately applied without applying a primer as a base treatment agent as in the prior art. The cyanoacrylate adhesive 16 is applied to the joining surface of either one of the magnet molded body 10 on which the magnet 12 is formed (the side of the adherend 14 in FIG. 1), and the magnet molded body 10 and the adherend are adhered as they are. The material 14 is bonded to the bonding surface, and the adhesive 16 is subjected to a curing reaction to bond the two together.

  At that time, since the resin coating film 12 contains Cu ions 18 in the adhesion curing accelerator added in advance to the resin coating composition liquid, the magnet molded body 10 is made of resin coating film. Even when bonded to the adherend 14 via 12, the adhesive reaction can be performed satisfactorily, and the magnet compact 10 and the adherend 14 can be firmly bonded and fixed.

Therefore, according to the present invention, various problems caused by performing an application process of an adhesion curing accelerator, that is, a primer solution as a base treatment agent, on a very small magnet molded body having an outer diameter of about 2 mm, That is, the primer cannot be applied to the magnet molded body with a uniform coating thickness, and thus the adhesive strength varies for each magnet molded body, or the complexity of manually applying the primer, The magnet molded body and the adherend are firmly bonded without causing problems such as an increase in labor and process for applying the primer solution to an extremely large number of small magnet molded bodies and an increase in costs caused thereby. It is possible to adhere and fix to the adherend, and it is possible to satisfactorily assemble the magnet compact to the adherend.
From the above points, the present invention is particularly suitable for application to a small ring-shaped magnet having an outer diameter of 5 mm or less or a small segment-type magnet having a width of 5 mm or less.

In the present invention, it is desirable to add an adhesion hardening accelerator so that the Cu ion has a concentration in the range of 2000 to 20000 ppm based on the solid content of the resin paint in the liquid of the resin paint composition. 2).
If the concentration is less than 2000 ppm, the effect of accelerating the curing of the cyanoacrylate adhesive is poor. Conversely, if the concentration exceeds 20000 ppm, the ratio of metal components in the liquid of the resin coating composition becomes too high, and the viscosity of the coating becomes too high. It becomes difficult to form a film.

Various resin coating methods can be used for resin coating for rust prevention, but spray coating is particularly suitable.
In particular, in the case of a small magnet having an outer diameter of φ5 mm or less, for example, a ring magnet molded body having a small hole diameter of about φ2 mm or a segment magnet molded body having a width of about 2 mm, this is accommodated in the rotating barrel and the rotating barrel is rotated. It is preferable to use barrel spray coating in which a liquid of the resin coating composition is spray-coated with a spray gun on a magnet molded body that rolls in a rotating barrel.

  By doing so, for example, a resin-coated film can be satisfactorily formed on the inner diameter side and outer diameter side of the ring-shaped magnet molded body and segment magnet molded body, and the outer diameter is also formed on the inner diameter side. The adhesion hardening accelerator can be evenly added to the side in a dispersed state.

The present invention can be applied not only to the case where the entire surface of the magnet molded body is coated, but also to the case where a part is coated, and the present invention can be applied to various magnet molded bodies. is there.
In particular, in the case of rare earth iron-based magnets, there is a problem that rust is likely to occur, and since a resin coating process is essential, it is particularly suitable for application to such rare earth iron-based magnets.

  Here, as the rare earth iron-based magnet, for example, Nd-Fe-B or Sm-Fe-N-based magnetic powder is pulverized and adjusted to a predetermined particle size, mixed with a thermosetting resin or a thermoplastic resin binder, and compression molded or Rare earth iron bond magnet obtained by injection molding, or rare earth iron hot work magnet obtained by orienting crystal grains while pressing Nd-Fe-B or Sm-Fe-N magnetic powder at high temperature Alternatively, it can be applied to rare earth iron-based sintered magnets obtained by finely pulverizing Nd—Fe—B or Sm—Fe—N alloy ingots and forming crystal grain orientation molding under a magnetic field, followed by sintering. .

  In the present invention, it is possible to perform coating treatment using various resin coating compositions. In particular, when the coating processing is performed using an epoxy resin resin coating composition and a curing agent using an amine. Applying to the effect is great.

  When a coating treatment is performed using an epoxy resin resin coating composition containing an amine-based curing agent, the amine-based curing agent is an inhibitor to the adhesion-curing reaction of the cyanoacrylate-based adhesive, and adhesion is difficult to be performed. In such a case, it is possible to perform good adhesion and fixation by applying the present invention.

Next, embodiments of the present invention will be described in detail below.
<Example 1>
The ultra-quenched Nd—Fe—B magnetic powder was pulverized to an average particle size of 100 μm, surface-treated with a silane coupling agent, and then mixed with a cresol novolac type epoxy resin.
This was compressed at a surface pressure of 10 ton / cm ² to obtain a green compact having an outer diameter φ2.1 mm, an inner diameter φ1.3 mm, and a height h4.7 mm.
Thereafter, heat treatment was performed at 150 ° C. for 30 minutes to cure the green compact and obtain a ring-shaped magnet compact.

On the other hand, an epoxy resin-containing resin coating composition liquid containing an amine-based curing agent prepared with the composition shown in Table 1 was coated with an organic copper compound-containing primer “7639” commercially available from Henkel Japan KK as an adhesion curing accelerator. In addition, a material adjusted to have a Cu ion of 2100 ppm on the basis of the solid content after curing is added, and the magnet molded body obtained above is accommodated in a rotating barrel, and the rotating barrel is rotated from the tank to the spray gun. The liquid of the resin coating composition was supplied and spray-coated on the magnet molding from the spray gun.
Then, this was heat-cured.

After that, with a UV bond cyanoacrylate anaerobic adhesive “3062U” manufactured by ThreeBond Co., Ltd., the coated magnet molded body was bonded to a nickel-plated Cu shaft (shaft dimensions: φ1.2 mm × 10.0 mm). Then, after the adhesive was cured, a pull-out test was performed under the following conditions to measure the pull-out strength.
The results are shown in Table 2.

<Pullout strength measurement>
As shown in FIG. 2, the bonded assembly of the magnet molded body 10 and the shaft 20 is installed on the pedestal 22, and the maximum load is applied to the shaft 20 by applying a force F in the axial direction at a speed of 1 mm per minute. The pulling strength was measured by measuring.

<Example 2>
The same magnetic molded body as in Example 1 was prepared by adjusting the same primer as described above so that Cu ions were 19000 ppm on the basis of the solid content after curing in the liquid of the resin coating composition. In addition to the liquid, this was used to apply a coating treatment to the magnet molded body, and then adhered to the Cu shaft in the same manner as described above, and then the pulling strength was measured.
The results are shown in Table 2.

<Comparative Example 1>
The same magnetic molding as in Example 1 was subjected to a coating treatment in the same manner as described above using the resin coating composition liquid to which the above-mentioned primer was not added. Adhesion was performed, and the pull-out strength was measured after the adhesive was cured.
The results are shown in Table 2.

  From the results of Table 2, it can be seen that good adhesion strength can be obtained by applying a resin coating using a resin coating composition liquid to which a primer is added.

  Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention can be implemented in variously modified forms without departing from the spirit of the present invention.

It is a conceptual diagram for demonstrating this invention. It is explanatory drawing of the method of the drawing strength measurement performed for adhesive force evaluation. It is a conceptual diagram explaining a prior art.

Claims (2)

It is a method for coating a magnet molded body in which a liquid of a resin coating composition is applied and coated on a magnet molded body that is bonded and fixed to an adherend on the other side with a cyanoacrylate adhesive,
An adhesion curing accelerator containing Cu component and generating Cu ions in the liquid of the resin coating composition is previously added to the liquid of the resin coating composition, and the liquid of the resin coating composition containing Cu ions is added. A method for coating a magnet molding, wherein the magnet molding is applied and coated.   In Claim 1, The said adhesion hardening accelerator is added so that the said Cu ion may become the density | concentration in the range of 2000-20000 ppm on the basis of solid content of this resin coating material in the liquid of the said resin coating composition. A method for painting a magnet compact.

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