JP2011159793A - Winding coil component manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a winding coil component manufacturing method for readily coping with the change in the size and the shape of a winding coil component which is to be a product, and efficiently manufacturing the winding coil component having exterior resin. <P>SOLUTION: For manufacturing the winding coil component includes the exterior resin 5, arranged to coat a winding wire 4 wound around the winding core portion of a magnetic core 3 having the winding core portion 1 and a pair of flanges 2a, 2b, arranged on both sides of the winding core portion, when the winding coil component is manufactured, a resin composition is prepared which contains an epoxy resin, acid anhydride, and microcapsule-type imidazole based latent hardener; and then after a solvent which has a polar group is added to the resin composition, the resin composition with the solvent added thereto is applied between a pair of flanges so as to coat the winding wire wound around the winding core portion, and hardened, the exterior resin is formed. As the solvent that has the polar group, at least one kind is used that is selected from among a group constituted of aromatic hydrocarbons, ester, alcoholic, ether, and ketone systems. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a wound coil component, and more specifically, a winding of a magnetic core having a winding core and a pair of flanges disposed on both ends thereof, wound around the winding core. The present invention relates to a method for manufacturing a wound coil component including an exterior resin disposed between a pair of flanges.

  For example, as shown in FIG. 4, a magnetic core 53 having a winding core portion 51 and a pair of flange portions 52 a and 52 b disposed on both ends thereof, A winding 54 wound around the core 51, an exterior resin 55 filled between the pair of flanges 52a and 52b so as to cover the winding 54 wound around the core 51, and the winding There is a wound coil component provided with external electrodes 56a and 56b to which both ends thereof are electrically connected.

In such a wound coil component, by applying and curing a magnetic powder-containing resin having a glass transition temperature of −20 ° C. or lower, more preferably −50 ° C. or lower, as the exterior resin. A wound coil component (surface-mounted coil component) having a formed exterior resin has been proposed (see Patent Document 1).
And when this magnetic coil containing exterior resin whose glass transition temperature is -20 degrees C or less, More preferably, -50 degrees C or less is used like this winding coil component, generation | occurrence | production of the crack of the flaw in a heat cycle test It is said that a coil component suitable for an application in which the temperature environment of use is prevented and the usage temperature environment changes drastically is obtained.

Also proposed is a wound coil component having an exterior resin formed by applying and curing a resin mixture containing 55% by weight or more of metal powder or a resin mixture containing 1 to 40% by weight of filler. (See Patent Document 2).
And according to this winding coil component, it is supposed that the reliability after environmental load tests, such as a heat shock, can be ensured.

Japanese Patent Laid-Open No. 2005-210055 JP 2008-300653 A

  As in Patent Document 1, when a magnetic powder-containing resin having a low glass transition temperature is used as the exterior resin, the flexibility of the exterior resin increases, so that the response to temperature changes is improved, and various sizes and shapes are available. It can be used for the wire-wound type coil parts, and versatility is improved. However, there is a problem that the package resin after curing is too soft, and the effect of improving the reliability by supplementing the mechanical strength of the magnetic core becomes insufficient.

  On the other hand, when the filler (such as silica powder or filler) such as metal powder is contained in the resin as in Patent Document 2, the reinforcing effect is improved, but the size and shape of the wound coil component are improved. Is different, it is necessary to adjust the filler content to an appropriate amount. For this reason, whenever the size or shape of the product changes, a resin composition containing a filler in an appropriate ratio must be prepared each time, which causes a problem of reducing productivity and increasing cost.

  The present invention solves the above-mentioned problems, and can easily cope with changes in the size and shape of a wound coil component as a product, and can efficiently manufacture a wound coil component including an exterior resin. It is an object of the present invention to provide a method for manufacturing a possible wound coil component.

In order to solve the above problems, a method for manufacturing a wound coil component according to the present invention includes:
A magnetic core having a winding core and a pair of flanges disposed on both ends thereof;
A winding wound around the core portion of the magnetic core;
A method of manufacturing a wound coil component comprising: an exterior resin filled between the pair of flanges so as to cover the winding wound around the winding core part,
Preparing a resin composition comprising an epoxy resin, an acid anhydride, and a microcapsule type imidazole-based latent curing agent;
Adding a solvent having a polar group to the resin composition;
And a step of applying the resin composition to which the solvent is added between the pair of flanges so as to cover the winding wound around the core part.

  As the solvent, it is desirable to use at least one selected from the group consisting of aromatic hydrocarbons, esters, alcohols, ethers, and ketones.

  The amount of the solvent added is desirably 3% by weight or more, and desirably less than 25% by weight.

In the method for manufacturing a wound coil component of the present invention, a resin composition containing an epoxy resin, an acid anhydride, and a microcapsule-type imidazole-based latent curing agent is prepared, and the resin composition includes a polar group. Is added in an amount corresponding to the size and shape of the wound coil component that is the product, and is applied between the pair of collars so as to cover the winding wound around the winding core, and is cured. As a result, it is possible to efficiently manufacture the wound coil component including the exterior resin having an appropriate magnetic core reinforcing effect.
That is, in the method of manufacturing a wound coil component according to the present invention, the amount of the solvent to be added can be widened. Therefore, by adjusting the amount, the characteristics (Tg, elastic modulus) of the cured exterior resin can be adjusted. , Residual stress) can be controlled to obtain a highly reliable wound coil component.

  In the present invention, by adding a solvent having a polar group before applying (giving) the resin composition to the magnetic core, the capsule covering the imidazole constituting the microcapsule type imidazole-based latent curing agent is eroded. (Swells), the imidazole-based curing agent covered with the capsule is exposed and comes into contact with the main material (epoxy resin), and functions as a curing agent. And the new capsule stable with respect to a heat | fever is formed by the hardening reaction with a main ingredient (epoxy resin) progressing in the surface layer of an imidazole particle. By forming this new capsule, the curing ability of imidazole, which is a curing agent, is inactivated, and the curing of the resin is suppressed. Then, the cured coating film (exterior resin) formed by curing (resining) the resin composition applied (given) to the magnetic core achieves low Tg and low elasticity, and imparts appropriate flexibility. As a result, it is possible to prevent the magnetic core from being cracked or chipped due to the residual stress of the exterior resin.

  In addition, since the degree of inactivation of the curing ability depends on the addition amount of the solvent having a polar group, the physical property of the exterior resin (the physical property of the cured coating film) can be controlled by the addition amount of the solvent. Therefore, it is possible to control the physical properties of the cured coating film according to the size and shape of the magnetic core without adjusting the composition of the resin composition only by adjusting the addition amount of the solvent. By simply preparing the resin composition, various wound coil components including the exterior resin can be easily and efficiently manufactured.

  In the present invention, the “microcapsule type imidazole-based latent curing agent” refers to an imidazole-based curing agent that is an isocyanate compound, an epoxy compound, a polyacid, a polyphenylene oxide, a polyacetal, a polyarylate, a polyester, a polycarbonate, a polyether ether. It is a curing agent that is held in a capsule composed of at least one of side, polyicid, polysulfone, polyethersulfone, and polyallylsulfone. Examples of imidazole curing agents include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-aminoethyl-2-methylimidazole, 1 -(2-hydroxy-3-phenoxypropyl) -2-methylimidazole, 1- (2-hydroxy-3-phenoxypropyl) -2-ethyl-4-methylimidazole, 1- (2-hydroxy-3-butoxypropyl) ) -2-methylimidazole, 1- (2-hydroxy-3-butoxypropyl) -2-ethyl-4-methylimidazole. In particular, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, and 2-phenylimidazole are preferable from the viewpoint of achieving both low-temperature curability and storage stability, and 2-methylimidazole is most preferable.

In the present invention, the solvent having a polar group is a concept that means a solvent having a polar functional group in the molecule, which is an atomic group containing oxygen and nitrogen having a high electronegativity. Examples of the polar group include —OH, C═O, —COOH, —NH ₂ , —NO ₂ , —NH ₃ ⁺ , —CN, and the like.

  The resin composition used in the present invention includes an epoxy resin, an acid anhydride, a microcapsule type imidazole-based latent curing agent, an additive for improving the properties of the wound coil component, such as a metal or In addition, a filler such as an inorganic oxide may be included.

  In the present invention, as the solvent having a polar group to be added to the resin composition, at least one selected from the group consisting of aromatic hydrocarbons, esters, alcohols, ethers, and ketones is used. As a result, the physical properties of the exterior resin (the physical properties of the cured coating film) can be reliably controlled, and the present invention can be made more effective.

  Among the solvents listed above, especially alcohol-based, ether-based, and ketone-based solvents have strong polar groups, and can more reliably control the physical properties of the exterior resin (the physical properties of the cured coating film). Become.

  In the present invention, the rate of occurrence of magnetic core cracks is set to 0 by making the proportion of the solvent having the polar group in the resin composition after addition of the solvent 3% by weight or more. Can do.

  Moreover, when the ratio of the solvent having the polar group to the entire resin composition after the addition of the solvent is 25% by weight or more, the capsule that originally constitutes the microcapsule type imidazole-based latent curing agent contained in the resin composition is obtained. While the degree of erosion (swelling) increases, the subsequent formation of new capsules may proceed excessively, resulting in insufficient curing of the exterior resin, resulting in insufficient magnetic core reinforcing effect. Therefore, the amount of the solvent having a polar group is desirably less than 25% by weight.

It is front sectional drawing which shows the winding coil component element of the stage before arrange | positioning exterior resin prepared in the Example of this invention. It is a top view which shows the winding coil component element of the stage before arrange | positioning exterior resin prepared in the Example of invention. It is front sectional drawing which shows the winding coil components manufactured by the method concerning the Example of this invention. It is front sectional drawing which shows the conventional winding coil component provided with exterior resin.

  Embodiments of the present invention will be described below to describe the features of the present invention in more detail.

<Example 1>
[1] Preparation of Resin Composition First, the following raw materials were weighed and mixed to prepare a resin composition at a stage before adding a solvent having a polar group.
(a) Aliphatic polyglycidyl ether 12g
(b) Acid anhydride 16g
(c) Silane coupling agent 1g
(d) 70 g of silica
(e) 1 g of microcapsule type imidazole-based latent curing agent

  Then, butyl cellosolve as a solvent having a polar group is added to a resin composition not containing a solvent so that the proportion of the total resin composition is 3% by weight, and a resin composition containing the solvent having a polar group is obtained. Produced.

[2] Production of wound coil component provided with exterior resin In this example, as shown in FIG. 1 and FIG. 2, as the wound coil component element to which the resin composition is applied, A magnetic core 3 having a pair of flange portions 2a and 2b disposed on both ends thereof, and a winding 4 wound around the core portion 1 of the magnetic core 3 and having an insulating coating on the surface, A winding coil component element (winding coil component before disposing the exterior resin) A1 provided with external electrodes 6a and 6b to which both ends of the winding 4 are electrically connected was prepared.
The magnetic core 3 constituting the coiled coil component element A1 has dimensions of length L = 3.2 mm, width W = 2.5 mm, and height T = 1.7 mm.

  Then, as shown in FIG. 3, the polarity of the winding coil component element A1 between the pair of flange portions 2a and 2b of the magnetic core 3 is covered so as to cover the winding 4 wound around the core portion 1. The resin composition 5a to which a solvent having a group was added was applied and filled using a dispenser applicator.

  The wound coil component element A1 coated and filled with the resin composition 5a is heat-treated at 90 ° C. for 30 minutes to dry the resin composition 5a, and then heat-treated at 150 ° C. for 60 minutes. Then, as shown in FIG. 1, a wound coil component A provided with the exterior resin 5 was manufactured.

[3] Preparation of cured resin film for characteristic evaluation In addition, in order to evaluate the characteristics of a cured resin to be an exterior resin obtained by curing a resin composition to which a solvent having a polar group is added, The same resin as the applied resin composition, that is, a resin composition added with 3% by weight of butyl cellosolve as a solvent was applied, and the same conditions as described in the above [2] (drying conditions: 90 ° C., 30 minutes) Curing conditions: 150 ° C., 60 minutes) were dried and cured to produce a cured resin film having a width of 10 mm, a length of 50 mm, and a thickness of 0.5 mm.

[4] Measurement and evaluation of characteristics
(1) Measurement of glass transition point (Tg) The glass transition point (Tg) was measured using a dynamic viscoelastic device (DMS110 manufactured by SII) using the cured resin film prepared by the method described in [3] above as a sample. The measurement was performed at a temperature rising rate of 10 ° C./min. The peak position of tan δ was defined as the glass transition temperature (Tg).
The Tg value of the cured resin film (exterior resin) is usually desirably 70 ° C. or lower.

(2) Elastic modulus The elastic modulus is based on JIS K7171 using a universal testing machine (Tensilon UCT-IT manufactured by Orientec Co., Ltd.) using a cured resin film prepared by the method described in [3] above as a sample. It was measured.
The elastic modulus of the cured resin film (exterior resin) is usually desirably less than 8000 MPa.

(3) Crack generation rate of magnetic core The occurrence state of cracks in the magnetic core (breakage rate of cracks) was examined by observing the appearance and cross section of the wound coil component A manufactured by the method described in [2] above.

(4) Strength of coiled coil parts The coiled coil parts produced by the above method [2] are housed in the taped part continuous tape (tape wound around the reel) storage part to produce a series of taped parts. The strength of the winding coil component was evaluated by examining whether or not the winding coil component was cracked or chipped when the winding coil component was stored in the tape.
The characteristics examined as described above are shown in Table 1. In Table 1, the strength of the wound coil component was determined to be good if no cracks or chips were observed in the process of manufacturing the taping component series.

<Example 2>
In Example 1 above, a resin composition to which 3% by weight of butyl cellosolve was added as a solvent having a polar group was used. In Example 2, the amount of butyl cellosolve added was 7% by weight. Other than that, the sample was produced on the same conditions as the case of the said Example 1, and the characteristic was evaluated by the same method as the case of the said Example 1. FIG.

<Example 3>
In Example 1 above, a resin composition to which 3% by weight of butyl cellosolve was added as a solvent having a polar group was used, but in Example 3, the amount of butyl cellosolve added was 10% by weight. Other than that, the sample was produced on the same conditions as the case of the said Example 1, and the characteristic was evaluated by the same method as the case of the said Example 1. FIG.

<Example 4>
In Example 1, the resin composition to which 3% by weight of butyl cellosolve was added as a solvent having a polar group was used. In Example 4, the amount of butyl cellosolve added was 15% by weight. Other than that, the sample was produced on the same conditions as the case of the said Example 1, and the characteristic was evaluated by the same method as the case of the said Example 1. FIG.

<Example 5>
In Example 1 above, a resin composition to which 3% by weight of butyl cellosolve was added as a solvent having a polar group was used. In Example 5, the amount of butyl cellosolve added was 20% by weight. Other than that, the sample was produced on the same conditions as the case of the said Example 1, and the characteristic was evaluated by the same method as the case of the said Example 1. FIG.

<Example 6>
In Example 6, instead of butyl cellosolve used in Example 1 above, carbitol was used as a solvent having a polar group, and the amount added was 3% by weight. Other than that, the sample was produced on the same conditions as the case of the said Example 1, and the characteristic was evaluated by the same method as the case of the said Example 1. FIG.

<Example 7>
In this Example 7, instead of the butyl cellosolve used in Example 1 above, methyl ethyl ketone was used as a solvent having a polar group, and the amount added was 3% by weight. Other than that, the sample was produced on the same conditions as the case of the said Example 1, and the characteristic was evaluated by the same method as the case of the said Example 1. FIG.

<Example 8>
In Example 8, the dimensions of the magnetic core are as follows: length L = 4.0 mm, width W = 4.0 mm, height T = 2.0 mm (in Example 1, length L = 3.2 mm, width W = 2.5 mm, height T = 1.7 mm), a sample was prepared under the same conditions as in Example 1, and the characteristics were evaluated in the same manner as in Example 1.

<Example 9>
In Example 9, the dimensions of the magnetic core are as follows: length L = 2.0 mm, width W = 2.0 mm, height T = 1.5 mm (in Example 1, length L = 3.2 mm, width W = 2.5 mm, height T = 1.7 mm), a sample was prepared under the same conditions as in Example 1, and the characteristics were evaluated in the same manner as in Example 1.

<Comparative Example 1>
In Example 1, a resin composition to which 3% by weight of butyl cellosolve was added was used. In Comparative Example 1, a resin composition to which butyl cellosolve was not added (butyl cellosolve 0% by weight) was used. Other than that, the sample was produced on the same conditions as the case of the said Example 1, and the characteristic was evaluated by the same method as the case of the said Example 1. FIG.

<Comparative example 2>
In Example 1 above, a resin composition to which 3% by weight of butyl cellosolve was added was used. In Comparative Example 2, hexane having no polar group was added at a rate of 3% by weight in place of butyl cellosolve. A resin composition (butyl cellosolve 0% by weight) was used. Other than that, the sample was produced on the same conditions as the case of the said Example 1, and the characteristic was evaluated by the same method as the case of the said Example 1. FIG.
The characteristics examined in each of the above examples and comparative examples are also shown in Table 1.

  As shown in Table 1, in the case of Examples 1 to 9 having the requirements of the present invention, the glass transition point (Tg), the elastic modulus, the crack occurrence rate of the magnetic core, and the strength of the wound coil component are good. It was confirmed that a result was obtained.

  Although not shown in Table 1, as a solvent having a polar group, a sample was prepared under the same conditions as in Example 1 except that the addition amount of butyl cellosolve was 1% by weight. When the characteristics were evaluated by the same method as in, a few cracks occurred in the magnetic core in the produced wound coil component (incidence rate <10%). It should be noted that no defect occurred in the process of manufacturing the taping component series by storing the coiled coil component in the tape storage part.

  Although not shown in Table 1, as a solvent having a polar group, a sample was prepared under the same conditions as in Example 1 except that the addition amount of butyl cellosolve was 25% by weight. When the characteristics were evaluated by the same method as in Example 1, a little defect occurred in the process of manufacturing the taping component series by storing the wound coil component in the tape storage portion. However, in the manufactured wound coil component, no cracking of the magnetic core was observed.

From these results and the results shown in Table 1 above, it is usually considered that the amount of the solvent having a polar group added is desirably 3% by weight or more and less than 25% by weight.
However, depending on the polarity of the solvent having a polar group (that is, depending on the type of solvent used), it may be desirable to add the solvent to less than 3% by weight or 25% by weight or more. Presumed to be possible.

  On the other hand, in Comparative Example 1 using a resin composition to which a solvent having a polar group was not added, the cured coating film (exterior resin) had a high glass transition temperature (Tg) and a large elastic modulus. In the wound coil parts, the occurrence of cracks in the magnetic core was observed at a high rate.

  In the case of Comparative Example 2 in which hexane not having a polar group was added as a solvent, the cured coating film (exterior resin) had a high glass transition temperature (Tg) and a large elastic modulus. In coil parts, the occurrence of cracks in the magnetic core was observed at a high rate.

  From the above results, according to the present invention, it is possible to control the physical properties of the cured coating film according to the size and shape of the magnetic core, without adjusting the blending of the resin composition, only by adjusting the addition amount of the solvent. That is, it turns out that it can respond easily to various winding coil components with the same resin composition.

  In the above examples, the case where the resin composition does not contain a metal powder or a filler for improving characteristics has been described as an example. However, as a resin composition, the metal powder or It is also possible to use a material containing a filler for improving characteristics.

  The present invention is not limited to the above examples in other points as well, and relates to the shape of the magnetic core, the number of turns of the winding, the type and blending ratio of raw materials constituting the resin composition, the type of solvent, etc. Various applications and modifications can be made within the scope of the invention.

DESCRIPTION OF SYMBOLS 1 Core part 2a, 2b Eaves part 3 Magnetic core 4 Winding 5 Exterior resin 5a Resin composition 6a, 6b External electrode A1 Winding coil component element A Winding coil component

Claims (4)

A magnetic core having a winding core and a pair of flanges disposed on both ends thereof;
A winding wound around the core portion of the magnetic core;
A method of manufacturing a wound coil component comprising: an exterior resin filled between the pair of flanges so as to cover the winding wound around the winding core part,
Preparing a resin composition comprising an epoxy resin, an acid anhydride, and a microcapsule type imidazole-based latent curing agent;
Adding a solvent having a polar group to the resin composition;
Applying the resin composition to which the solvent is added between the pair of brim parts so as to cover the winding wound around the core part. Production method.   2. The method for manufacturing a wound coil component according to claim 1, wherein the solvent is at least one selected from the group consisting of aromatic hydrocarbons, esters, alcohols, ethers, and ketones.   2. The method of manufacturing a wound coil component according to claim 1, wherein the amount of the solvent added is 3% by weight or more.   2. The method of manufacturing a wound coil component according to claim 1, wherein the amount of the solvent added is less than 25% by weight.

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