JP2630890B2 - Thermosetting adhesive paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive paint, and more particularly to a thermosetting adhesive paint for a self-fusing insulated wire used for a voice coil of a speaker and a paper tube supporting a coil.

[0002]

2. Description of the Related Art Generally, a voice coil is formed by tightly winding a plurality of layers of a self-fusing insulated wire while applying an alcohol-based solvent onto a coil supporting paper tube (hereinafter abbreviated as a paper tube), heating and drying the wire. It is obtained by fusing the space between the paper tube and the wire loop and integrating them. Self-fusing insulated wires are those in which an adhesive coating is applied to the conductor via an insulating coating and then baked to provide an adhesive coating. A film is provided. The adhesive film of the self-fusing insulated wire and the adhesive film of the paper tube are preferably made of the same resin or a resin of the same system in terms of adhesion between the paper tube and the wire. Therefore, the same adhesive paint or the same kind of adhesive paint is preferably used as the adhesive paint for the self-fusing insulated wire and the adhesive paint for the paper tube (hereinafter, these adhesive paints are abbreviated as the adhesive paint for voice coil). .

Conventionally used adhesive coatings for voice coils include those obtained by dissolving a thermoplastic resin soluble in an alcohol-based solvent, for example, a polyvinyl butyral resin or an alcohol-soluble polyamide resin, in an organic solvent.
Alternatively, there is a product obtained by adding a curing component such as an epoxy resin to an alcohol-soluble polyamide resin and dissolving the same in an organic solvent.

[0004]

In recent years, audio equipment such as a stereo has been required to have high output and high performance, and the load applied to a speaker has become more and more severe. A voice coil used for the audio equipment has also been required to have excellent heat resistance. Have been. When the thermal destruction phenomenon in the continuous overload test of the voice coil is observed, it occurs most often at the bonding interface between the paper tube and the wire ring, and then between the wires. The main reasons for this are as follows: (1) Since the thermal expansion coefficients of the paper tube and the wire loop are different, distortion occurs in both. (2) Deviation between the paper tube and the wire loop due to vibration and heat generated by the coil. In the worst case, this causes the wire loop to fall off the paper tube, impairing its function as a voice coil.

[0005] The resin between the wires of the voice coil manufactured from the self-fusing insulated wire and the paper tube obtained by using the above-mentioned adhesive paint and the resin at the bonding portion between the paper tube and the wire loop are fundamentally heat. Due to the plasticity, the adhesive strength is significantly reduced at high temperatures, and the heat resistance is not sufficiently satisfactory. Therefore, it cannot be used for audio equipment such as a stereo that requires high output and high performance. In addition, the resin between the wires of the voice coil manufactured from the self-fusing insulated wire and the paper tube obtained by using the above-mentioned adhesive paint, and the resin of the bonding portion between the paper tube and the wire are mixed with a hardening component. As a result, the heat resistance improved, but it was still insufficient. In addition, the adhesive coating of the self-fusing insulated wire and paper tube obtained by using the adhesive coating of
The curing component in the adhesive film impairs the resolubility of the alcohol-soluble polyamide resin, which is the main component, in alcohol-based solvents and impairs the initial adhesive properties. The work was hindered.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. By using a specific composition as an adhesive coating for a voice coil, it is possible to provide a particularly high load between a paper tube and a wire loop. The object of the present invention is to improve the heat-resistant adhesive strength of the voice coil and to improve the initial adhesive properties of the voice coil.

[0007]

In order to achieve the above object, the present invention provides an alcohol-soluble alicyclic epoxy resin based on 100 parts by weight of an alcohol-soluble polyamide resin.
10 to 40 parts by weight, 20 to 70 parts by weight of an epoxy resin other than the alcohol-soluble epoxy resin, bismaleimide compound
20-80 parts by weight, alkyl etherified amino resin 2-8
The thermosetting adhesive paint is obtained by adding 10 to 40 parts by weight of a thermosetting phenol resin and dissolving the same in an organic solvent.

Further, the thermosetting adhesive paint is a thermosetting adhesive paint which is subjected to aging treatment for a time determined by the following formula (1).

[0009]

(Equation 1) Here, T is the aging temperature (° K), and H is the aging time (hr).

The alcohol-soluble polyamide resin used in the present invention is a resin which is a main component of the adhesive coating of the present invention.
An adhesive film forming component is a highly flexible linear polymer that is soluble in an alcoholic solvent such as methanol or a phenolic solvent and has good compatibility with other materials. Specifically, Amilan CM-4000 (trade name of Toray), Ultramid 1C (trade name of BASF, Germany) composed of a copolymer of 6-10 nylon and 6 or 6,6-nylon, etc., and Platamide M1425 ( Japan Rilsan Co., Ltd.).

The alcohol-soluble alicyclic epoxy resin (hereinafter abbreviated as alcohol-soluble epoxy resin) used in the present invention is soluble in an alcohol-based solvent, has a basic skeleton of a molecular structure of an alicyclic type, and has an epoxy equivalent. Those which are 150-500 are desirable. Specific examples include EHPE-3150 (trade name of Daicel Chemical Industries, Ltd.). This alcohol-soluble epoxy resin improves the resolubility of the adhesive film in alcoholic solvents (hereinafter abbreviated as alcohol resolubility),
It is a component added to improve the initial adhesive properties. When the epoxy equivalent is less than 150, heat resistance is impaired due to low molecular weight, and when it exceeds 500, reactivity is poor.

An epoxy resin other than the alcohol-soluble epoxy resin (hereinafter abbreviated as epoxy resin) used in the present invention is a compound having an epoxy ring at a terminal, and is used to improve film-forming ability, swellability, and crosslink density. It is a component to be added. Specific examples include bisphenol-based epicoats # 1001, # 1004, # 1007, and # 1009 (trade names of Yuka Shell Co., Ltd.). In addition, considering the heat resistance and reactivity, Araldite which is a polyfunctional novolak type epoxy resin
ECN 1235, 1280, 1299 (all are trade names of CHIBA), DEN
It is more effective to use 431, 438 (both are trade names of Dow Chemical Company) and the like. These epoxy resins may be used alone, or may be used in combination according to desired properties.

The bismaleimide compound used in the present invention is a component that contributes to heat curing and imparts heat resistance, and the one represented by the following chemical formula 1 is used.

[0014]

Embedded image

In the above formula 1, R represents a divalent aliphatic or aromatic hydrocarbon. Specifically, N, N-ethylenebismaleimide, N, N-hexamethylenebismaleimide, N, N-trimethylhexamethylenebismaleimide, N,
N-methylenediparaphenylenebismaleimide, N, N-paradiphenylsulfonebismaleimide and the like can be mentioned.

The alkyl etherified amino resin used in the present invention is a component that contributes to heat curing and imparts heat resistance, and includes benzoguanamine resin, phthalodiguanamine resin,
It is obtained by subjecting CTU-guanamine resin, melamine resin, urea resin and the like to methylol with formaldehyde, and then subjecting the methylol compound to alkyl etherification with alcohol. Specifically, Delamine CTU-100, MT-30, A-
100SL (both are trade names of Fuji Kasei), Beckamine P-138
(Dai Nippon Ink Co., Ltd.).

The thermosetting phenolic resin used in the present invention is a component that contributes to thermosetting and imparts heat resistance.
Reaction by heat treatment at ~ 220 ℃ for 10 ~ 30 minutes,
One that cures is desirable. Specifically, the laser top PL-220
7, PL-2407, PS-2772, PS-2780 (all are trade names of Gunei Chemical Industry Co., Ltd.) and the like.

The reason why the amount of each resin added to the alcohol-soluble polyamide resin is limited will be described.
The reason why the addition amount of the alcohol-soluble epoxy resin is limited to 10 to 40 parts by weight is that when the amount is less than 10 parts by weight, the effect of improving the alcohol resolubility (initial adhesive property) is not seen, and the addition of 40 parts by weight This is because if it exceeds the number, the heat-resistant adhesive strength of the heat-treated voice coil is impaired. The reason for limiting the addition amount of the epoxy resin to 20 to 70 parts by weight is that exceeding this range will adversely affect the film-forming ability, swellability and crosslink density. The amount of the bismaleimide compound added is 20 to
The reason for limiting to 80 parts by weight is that if it is less than 20 parts by weight, the crosslink density becomes low and heat resistance is impaired, and if it exceeds 80 parts by weight, film forming properties and alcohol resolubility (initial adhesion properties) are impaired. That's why. The reason why the addition amount of the alkyl etherified amino resin is limited to 2 to 8 parts by weight is that when the amount is less than 2 parts by weight, the effect of improving the heat-resistant adhesive strength of the heat-treated voice coil is not so large, and 8 parts by weight. If the ratio exceeds the above, the crosslink density increases in a drying furnace during the production of the paper tube and the self-fusing insulated wire, and the alcohol redissolvability (initial adhesive property) is impaired. The reason for limiting the amount of the thermosetting phenolic resin to 10 to 40 parts by weight is as follows.
If the amount is less than 10 parts by weight, sufficient heat resistance cannot be obtained, and if it exceeds 40 parts by weight, the film-forming property and alcohol resolubility (initial adhesive properties) are impaired.

In the present invention, the thermosetting adhesive paint is subjected to aging treatment for a time determined by the above formula (1),
The alcohol resolubility is determined by the reaction rate constant K of the paint, and a linear relationship is established between the reaction rate constant K of the adhesive paint of the present invention and the reciprocal 1 / T (° K) of the absolute temperature. And the Arrhenius equation, the vertical axis represents aging time (hr), and the horizontal axis represents the reciprocal of absolute temperature 1 / T.
When the above equation 1 is plotted on the semi-log scale graph of FIG. 1 with (° K), it is represented by a straight line L, and it has been found that the portion above this straight line L is in the good resolubility range. It is. Therefore, the minimum aging treatment time is, for example, when the aging temperature is 30 ° C. (303 ° K) or 40 ° C. (313 ° C.).
K) and 50 ° C. (323 ° K), respectively.
hr, 47 hr and 21 hr. The Arrhenius equation is shown in Equation 2 below.

[0020]

(Equation 2) Here, K is a reaction rate constant, E is activation energy, R is a gas constant, A is a constant, and T is an absolute temperature ° K.

[0021]

The adhesive coating composition of the present invention comprises an alcohol-soluble polyamide resin as a main component, an alcohol-soluble epoxy resin contributing to alcohol resolubility (initial adhesive properties), an epoxy resin contributing to film forming ability, and a thermosetting. Since it is a thermosetting adhesive paint to which a bismaleimide compound, an alkyl etherified amino resin and a thermosetting phenol resin are added, the adhesive paint of the present invention can be used to re-dissolve in an alcohol-based solvent, that is, paper in a semi-cured state. It can be applied and dried on a tube and can be applied and baked on a conductor via an insulating film in a semi-cured state. Then, the obtained paper tube and the self-fusing insulated wire are densely coated with a plurality of layers while the alcohol-based solvent is applied onto the paper tube and the self-fusing insulated wire has a good alcohol resolubility (initial adhesive property). The wound voice coil can be wound, and at the stage of heat treatment after winding, each resin contributing to the thermosetting reacts, entangles with the molecular chains of the alcohol-soluble polyamide resin and other additive resins, The resin between the wires, and the resin at the bonding portion between the paper tube and the wire loop form a three-dimensional network structure,
The insolubility imparts heat resistance. Thereby, even if the temperature rise of the voice coil becomes large, the function is maintained.

The ripening temperature T determined by the above equation (1)
(° K) and the aging time H (hr) or more (FIG. 1)
In the above, a part above the straight line L) By aging the adhesive coating of the present invention, a part of the added resin is reacted to further improve the alcohol resolubility (initial adhesive strength).

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the contents of the present invention will be described with reference to embodiments. The present invention is not limited to the present embodiment,
The self-fusing insulated wire obtained by using the adhesive paint of the present invention can be used for winding of a self-supporting coil, a deflection yoke, a motor coil and the like.

(1) Preparation of Adhesive Paint An alcohol-soluble epoxy resin, an epoxy resin, a bismaleimide resin, an alkyl etherified amino resin, and a thermosetting phenol resin are added to an alcohol-soluble polyamide resin in the composition shown in Table 1. It was dissolved in a mixed solvent of cresol / xylene to prepare an adhesive coating having a concentration of 12%.

[0025]

[Table 1]

(2) Manufacture of paper tube The adhesive paint prepared in the above (1) was applied to a 0.07 mm thick polyimide glass cloth with a bar coater.
Leave in a constant temperature bath for 2 minutes to dry to a semi-cured state,
A paper tube having a 0.010 mm adhesive layer was produced. A, B
The paper tubes coated with the adhesive paints C and C were dried, respectively.
P, BP and CP.

(3) Manufacture of self-fusing insulated wire A polyesterimide insulating paint is applied to a copper wire having a conductor diameter of 0.30 mmφ and baked so as to have a finish outer diameter of 0.320 mm. Apply the applied adhesive paint evenly,
It was baked in a semi-cured state to produce a self-fusing insulated wire having an adhesive film thickness of 0.006 mm. The wires coated and baked with the adhesive paints of A, B and C are respectively AW, BW and CW
And

(4) Manufacture of voice coil The paper tube obtained in the above (2) is cut into a rectangular shape having a width of 25 mm and a length of 75 mm, and is attached cylindrically to a winding jig with the adhesive layer on the outside. Methanol was applied to the self-fusing insulated wire obtained in (3) above, and the adhesive film was swelled and dissolved to form a tightly wound array. Table 2 shows the combinations of the paper tube and the self-fusing insulated wire. After the winding is completed, the voice coil is dried at room temperature for 1 hour, and then heat-treated in a thermostat at 180 ± 5 ° C. for 30 minutes to completely cure the resin in the semi-cured bonded portion, and the voice coil for testing. Was manufactured.

[0029]

[Table 2]

The combination of the paper tube and the self-fusing insulated wire is not limited to the first to third embodiments, but may be any combination.

Comparative Example As an adhesive paint for a voice coil of a comparative example, (a) an adhesive paint obtained by dissolving a polyvinyl butyral resin in an organic solvent and (b) 100 parts by weight of an alcohol-soluble polyamide resin and 30 parts by weight of an epoxy resin as a curing component. A paper tube and a self-fusing insulated wire were manufactured in the same manner as in the example using an adhesive coating in which a part was added and dissolved in an organic solvent, and then a test voice coil was manufactured. Voice coils corresponding to the adhesive paints of (a) and (b) were used in Comparative Examples 1 and 2, respectively.
And The heat treatment conditions during the production of the voice coil were set at 90 ° C. × 15 minutes for Comparative Example 1 and 120 ° C. × 15 minutes for Comparative Example 1 in consideration of the characteristics of each resin.

Heat Resistance Bond Strength Test The heat resistance bond strength test of the test voice coils obtained in the examples and comparative examples will be described with reference to the drawings. Fig. 2 (a),
(b) is a front view and a side view of the test piece for measuring the heat-resistant adhesive strength between the paper tube and the wire loop of the voice coil.

When one portion of the test voice coil is cut at right angles to the coil and spread, a strip in which the polyimide glass cloth (paper tube) 1 and the wire ring 2 are tightly integrated is obtained. Next, the polyimide glass cloth 1 and the wire ring 2 are peeled off from the end so that the bonding portion 3 of 10 mm remains at the center. Next, the test piece 4 is obtained by cutting the polyimide glass cloth 1 and the wire loop 2 of the stripped portion from each other.

In order to measure the heat-resistant adhesive strength of the test piece 4, one end of each test piece was fixed to the upper part in a thermostat, and the other end was fixed to the other end.
After applying a load of 500 g, the thermostat was closed, the temperature was raised from room temperature at a rate of about 2 ° C./min, and the temperature when the load dropped was read. This temperature was defined as the adhesive breaking temperature between the paper tube and the wire loop. n = 5, and the results are shown in Table 3.

[0035]

[Table 3]

As is apparent from Table 3, the voice coil manufactured using the adhesive coating composition of the present invention has an extremely high heat-resistant adhesive strength since the adhesive breaking temperature between the paper tube and the wire ring is extremely high. .

Aging treatment of adhesive paint and alcohol resolubility (initial adhesive strength) test Adhesive paints of Examples A, B, and C obtained in (1) above and adhesive paints of Comparative Examples (A) and (B) About the aging temperature
30 ° C, 40 ° C, 50 ° C, 3 levels, aging time is 24 hours, 16
After aging treatment at three levels of 8 hours and 336 hours, a paper tube having a semi-cured adhesive layer and a self-fusing insulated wire were manufactured by the methods described in the above (2) and (3). Next, methanol was applied to the self-fusing insulated wire according to the method described in the above item (4), and the adhesive film was swelled and dissolved, and was wound tightly on a paper tube in an aligned manner. After winding, it was dried at room temperature to produce a voice coil for an initial adhesion test. At this time, the heat treatment performed in the above (4) was not performed. Next, the initial adhesive force between the wire loop and the paper tube was measured using an autograph (AG-5000B manufactured by Shimadzu Corporation). Table 4 shows the results. The reason why the alcohol resolubility is measured by the initial adhesive strength is that the resin at the bonding portion between the paper tube of the voice coil and the wire ring is mixed with the self-fusing insulated wire and the adhesive film of the paper tube dissolved with alcohol. This is because it has been found by experiments so far that a material having a large amount of dissolution (that is, having a good alcohol resolubility) has a good initial adhesive strength.

[0038]

[Table 4]

As can be seen from Table 4, the adhesive paints of Examples 1 to 3 of the present invention were subjected to aging treatment for a time determined by the above formula (1), that is, the initial adhesive strength of the voice coil, ie, self-fusion. It can be seen that the alcohol resolubility of the adhesive coating of the conductive insulated wire and the paper tube is improved.

[0040]

According to the voice coil obtained by using the thermosetting adhesive paint of the present invention, the resin between the wires and the resin at the bonding portion between the paper tube and the wire loop are removed at the heat treatment stage after the completion of the winding. Since a three-dimensional network structure is formed and insolubilized, the heat resistance becomes extremely good. Therefore, when the speaker is activated, the wire loop does not fall off the paper tube due to the heat generated by the voice coil itself, which is extremely effective as an adhesive paint for a voice coil used in a voice coil of a small, high-output speaker. I do. Further, the self-fusing insulated wire and the adhesive film of the paper tube obtained from the adhesive coating of the present invention aged for at least the time determined by the above-mentioned formula 1 have extremely good alcohol solubility, so that the initial stage of the production of the voice coil is improved. Since the adhesive strength is also extremely strong, there is no variation due to insufficient initial adhesive strength at the time of winding the voice coil, and the voice coil winding operation can be performed efficiently, which greatly contributes to the industry.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between aging treatment conditions and alcohol resolubility of a thermosetting adhesive paint of the present invention.

FIGS. 2A and 2B are a front view and a side view of a test piece for measuring a heat-resistant adhesive strength of a voice coil.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polyimide glass cloth (paper tube) 2 Wire loop (self-fusing insulated wire) 3 Adhesion part 4 Test piece L Straight line showing formula 1

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location H01B 7/02 H01B 7/02 B H04R 9/04 104 H04R 9/04 104B

Claims (2)

(57) [Claims] 1. An alcohol-soluble alicyclic epoxy resin of 10 to 40 parts by weight, an epoxy resin other than the alcohol-soluble epoxy resin of 20 to 70 parts by weight, a bismaleimide compound, based on 100 parts by weight of the alcohol-soluble polyamide resin. 20 to 80 parts by weight, and alkyl etherified amino resin
A thermosetting adhesive paint, wherein 8 parts by weight and 10 to 40 parts by weight of a thermosetting phenol resin are added and dissolved in an organic solvent. 2. The thermosetting adhesive paint according to claim 1, wherein the thermosetting adhesive paint is aged for a time determined by the following formula (1). (Equation 1) Here, T is the aging temperature (° K), and H is the aging time (hr).