JP7590752B2 - Coating resin stripping solution, coating resin stripping treatment solution, and coating resin stripping treatment method - Google Patents

Description

The present invention relates to a coating resin stripping solution for stripping coating resin from an insulated conductive wire, a coating resin stripping treatment solution, a coating resin stripping treatment method, and a method for recycling the conductor wire that constitutes the insulated conductive wire.

For example, polyvinyl formal resin, polyester resin, polyesterimide resin, polyamideimide resin, polyimide resin, etc. are used as coating resins for insulating and coating the conductor wire of an insulated conductive wire. Among them, resins containing imide groups, amide groups, and ester groups in the repeating units of polyesterimide, polyamideimide, polyimide, etc. are known as coating resins with excellent heat resistance. In a given electrical device, such insulated conductive wires are usually used by removing the coating resin at both ends (tips) to expose the conductor wire and perform the electrical connection function. With heat-resistant insulated conductive wires, there is a problem that the coating resin, such as polyimide, cannot be easily removed when exposing the conductor wire, for example, by heat treatment to the extent of soldering.

One common method for exposing the conductor wire is a physical stripping method that uses a stripping blade or irradiates a laser beam to remove the coating resin from the insulated conductive wire. Another known method is a chemical stripping method that uses a coating resin stripping solution and immerses the insulated conductive wire in the stripping solution to make it easier to remove the coating resin. Patent Documents 1 and 2 describe chemical stripping methods and coating removal solutions for stripping the coating resin from insulated conductive wires, and Patent Document 3 discloses a method and coating removal solution in which the coating resin in the technology of Patent Document 2 is specifically limited to polyimide resin.

Japanese Patent Application Publication No. 2-164213 JP 2013-27071 A JP 2013-211991 A

The method of chemically peeling off the coating resin using a treatment liquid is preferable in that it requires simpler coating resin treatment equipment than the method of physically removing the coating resin using a device equipped with a peeling blade or laser irradiation unit. In addition, the chemical peeling method is also superior in terms of productivity, since multiple insulated conductive wires can be immersed in the treatment liquid to peel off the coating resin at once. However, as explained below, there is a problem in that there is room for further improvement in terms of contributing to productivity.

Patent Document 1 states that, as a conventional method, "polyamide-imide or polyimide heat-resistant enameled wire is stripped using a sodium hydroxide solution at 50 to 90°C or an alkali-mixed molten bath at about 400 to 450°C" (page 1, right column, line 16). It also points out that "during heating, alkali particles may scatter and adhere to the insulating coating of the coil or lead wire. If such adhesion occurs, corrosion of the coating progresses over a long period of time, which is likely to cause a decrease in insulating performance or short-circuiting between layers of the coil" (page 2, left column, line 3).
In this way, when a high-temperature sodium hydroxide solution or an alkali molten bath is used as a coating resin stripping treatment solution, the treatment solution must be handled carefully, resulting in poor handling characteristics. In this respect, the treatment solution of Patent Document 1 has the drawback of impairing productivity.

Patent Document 2 discloses a coating resin treatment liquid that is separated into at least two layers: an upper layer liquid 21 that is a poor solvent for the resin coating, and a lower layer liquid 22 that is a solvent that has a pH of 9 or more under predetermined conditions and swells or dissolves the resin coating. Specifically, in the examples, when the resin coating is a polyurethane resin, a polyester resin, a polyvinyl formal resin, or an epoxy acrylic resin, the results of removing the coating resin by the following work procedures 1) to 4) are disclosed ([0039]).
1) Immersing the conductor assembly 10 in the coating removal treatment liquid 20;
2) After a predetermined time has elapsed, the conductor assembly 10 is removed from the coating removal treatment liquid 20.
3) The resin coating 11b of the tip portion 10a which has been immersed in the lower layer liquid 22 and swollen is peeled off.
4) The peeled resin coating 11b is removed to expose only the conductor wire 12.
Specifically, in [0032] of Patent Document 2, a technique for a peeling treatment that is essentially premised on swelling the coating resin is described.

Patent Document 3 limits the coating resin to polyimide and discloses a coating resin treatment liquid similar to Patent Document 2. In the coating removal treatment liquid for evaluation, the components of the lower layer liquid for peeling off the coating resin are about 70 to 80% polar solvent and contain monoethanolamine or diethanolamine as a neutralizing agent, similar to Patent Document 2. It is disclosed that, according to the same terminal treatment method as Patent Document 2, the tip of a resin-coated copper conductor was immersed in the coating removal treatment liquid, and after immersion for 3 minutes, compressed air was blown onto it to remove the swollen coating, and the peeling state was evaluated.
Thus, in Patent Documents 2 and 3, an organic solvent containing an organic agent is used as the coating resin stripping treatment liquid, and therefore, the handling is improved compared to the treatment liquid of Patent Document 1. However, in that the swollen coating resin needs to be wiped off afterwards, a treatment liquid that can further improve productivity is expected.

Furthermore, when wiping off the swollen coating resin in this way, the boundary between the exposed conductor wire and the end of the remaining coating resin tends to become roughly disturbed. This can partially impair insulation, and there is a risk that the safety of the electrical contacts connecting the conductor wires will be compromised. A treatment solution that does not impair safety and can improve productivity is desirable.

In addition, Patent Document 2 uses a coating removal treatment liquid whose pH is adjusted according to the resin to be stripped, and Patent Document 3 uses a coating removal treatment liquid whose pH is adjusted by adding a neutralizing agent according to the anionic or cationic polar group in the polyimide resin. In other words, Patent Documents 2 and 3 each use a coating removal treatment liquid whose components are finely adjusted for each resin, since the types of resin to be stripped are different. When fine adjustment of the components of the coating removal treatment liquid is required for each resin, a treatment liquid that can further improve productivity is expected in that a coating removal treatment liquid corresponding to each resin needs to be prepared.

In addition, in magnet wire, rectangular wire is often used to increase the occupancy rate of the winding. In the rectangular wire formed by rolling a round wire in one axial direction, one pair of opposing surfaces in the rolling direction may be flat, but the other pair of opposing surfaces may be formed with a gentle R shape. In such a case, the processing method of physically removing the coating resin requires preparation of a peeling blade corresponding to various R shapes so as not to cut the conductor wire, adjustment of the irradiation angle of the laser beam, and frequent part replacement and device adjustment, which reduces productivity. Therefore, in the coating resin removal processing of magnet wire, there is a strong demand for a chemical processing method using a coating removal processing solution.
In the following description, the term "magnet wire" is used to mean an insulated conductive wire for windings in electrical devices.

In view of the above problems, the present invention aims to provide a coating resin stripping solution, a coating resin stripping treatment solution, and a coating resin stripping treatment method that contribute to improving the productivity of removing the coating resin in a treatment solution for chemically stripping the coating resin from an insulated conductive wire.

The present invention is as follows.
[1] A coating resin remover for removing a coating resin from an insulated conductive wire having a conductor wire and a coating resin coating the conductor wire, comprising:
An inorganic alkali (A);
an alkanolamine (B) having 1 to 10 carbon atoms;
and water (C).
[2] The inorganic alkali (A) is contained in the coating resin stripping solution in an amount of 5 mass% or less,
The coating resin stripping solution according to [1], wherein the alkanolamine (B) is contained in the coating resin stripping solution in an amount of 15% by mass or more and 90% by mass or less.
[3] The coating resin stripper according to [1] or [2], wherein the alkanolamine (B) includes one or more selected from the group consisting of monoethanolamine, diethanolamine, N-methylethanolamine, N-ethylethanolamine, N-butylethanolamine, N-(2-aminoethyl)ethanolamine, and N-(2-aminoethyl)propanolamine.
[4] The coating resin stripping solution according to any one of [1] to [3] above, further comprising an aprotic polar solvent (D) having a boiling point of 100° C. or higher and 2 to 6 carbon atoms.
The aprotic polar solvent (D) may have a Hansen polarity parameter of 4.3 or more, expressed in units of (cal/ml) ^0.5 , and a Hansen hydrogen bonding parameter of 2.0 or more and 5.6 or less.
[5] A coating resin remover for removing a coating resin from an insulated conductive wire having a conductor wire and a coating resin coating the conductor wire, comprising:
an alkanolamine (B) having 1 to 10 carbon atoms;
Water (C);
and (D) an aprotic polar solvent having a boiling point of 100° C. or higher and a carbon number of 2 to 6.
[6] The coating resin stripper according to [4] or [5], wherein the aprotic polar solvent (D) contains one or more selected from the group consisting of dimethylsulfoxide, N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and 1,3-dimethyl-2-imidazolidinone.
[7] The coating resin stripper according to any one of [1] to [6], further comprising at least one alcohol-based solvent (E) having a boiling point of 100° C. or higher and selected from the group consisting of linear or branched alcohols having 2 to 6 carbon atoms and divalent to trivalent alcohols, and aromatic alcohols having 2 to 8 carbon atoms and monovalent to trivalent alcohols.
[8] The coating resin stripper according to any one of [1] to [7], wherein the cross-sectional shape of the conductor wire is circular or rectangular.
[9] The coating resin remover according to any one of [1] to [8], wherein the insulated conductive wire is a single-wire insulated conductive wire or an assembly-type insulated conductive wire having a plurality of the insulated conductive wires.
[10] The coating resin stripper according to [9], wherein the insulated conductive wire is a magnet wire and a standalone insulated conductive wire, and the conductor wire is a rectangular wire.
[11] The coating resin stripper according to any one of [1] to [10], wherein the coating resin is one or more selected from the group consisting of polyacetal resin, polyester resin, polyurethane resin, polyamide resin, polycarbonate resin, polyimide resin, polyesterimide resin, polyesterimide resin, polyamideimide resin, and polyesteramideimide resin.
[12] The coating resin stripper according to [11], wherein the coating resin is one or more selected from a polyester-based resin, a polyurethane-based resin, a polyamide-based resin, a polycarbonate, a polyimide-based resin, a polyesterimide resin, a polyesterimide resin, a polyamideimide resin, and a polyesteramideimide resin, and the coating resin stripper is of a dissolution stripping type that dissolves and strips the coating resin.
[13] The coating resin stripping solution according to [11], wherein the coating resin is a polyacetal resin, and the coating resin stripping solution is of a swelling stripping type that swells and strips the coating resin.

[14] A release treatment layer containing the coating resin stripping solution according to any one of [1] to [12] above;
A coating resin stripping treatment liquid comprising: an oily component including a higher aliphatic hydrocarbon; and an evaporation prevention layer disposed on the release treatment layer separately from the release treatment layer.

[15] A coating resin stripping method using the coating resin stripping solution according to any one of [1] to [13] or the coating resin stripping treatment solution according to [14],
Immersing the insulated conductive wire in the coating resin stripping solution having a temperature of 75° C. or higher and 120° C. or lower;
and exposing the conductor wire.
[16] The coating resin peeling treatment method according to [15], wherein the immersion time is 60 minutes or less.
[17] The coating resin dissolution treatment method according to [15] or [16], further comprising providing an evaporation prevention layer containing an oily component including a higher aliphatic hydrocarbon on the coating resin stripping solution.
[18] The coating resin stripping method according to any one of [15] to [17], wherein the coating resin stripping solution remaining after the first coating resin stripping treatment is carried out, or after the first treatment, or after any further treatment if further treatment is carried out, is continuously used.
[19] The material of the conductor wire is copper, a copper alloy, aluminum, or an aluminum alloy,
the coating resin is at least one selected from the group consisting of polyacetal resins, polyester resins, polyurethane resins, polyamide resins, polyether resins, polyimide resins, polyesterimide resins, polyesteramideimide resins, polyamideimide resins, and polyetherimide resins;
The coating resin stripping method according to any one of [15] to [18], wherein even when the materials of the conductor wires are different and/or even when the types of the coating resins are different, one type of coating resin stripping solution is used.
[20] A method for reusing a conductor wire constituting an insulated conductive wire, comprising: immersing the insulated conductive wire in the coating resin stripping liquid or the coating resin stripping treatment liquid described in any one of [1] to [13] above or the coating resin stripping treatment liquid described in [14] above, heated to 75°C or higher and 120°C or lower, exposing the conductor wire, recovering the exposed conductor wire, and reusing the exposed conductor wire.

According to the coating resin remover of the present invention, the coating resin can be easily dissolved or swelled and removed by simply immersing the insulated conductive wire in the remover or the treatment liquid for stripping, which contributes to improving productivity. Moreover, at the boundary surface of the remover or the treatment liquid for stripping, the edge of the coating resin that remains unstripped and the conductive wire exposed from the end of the coating resin are clearly bounded. Furthermore, according to the present stripper, the coating resin can be easily dissolved or swelled and removed from any insulated conductive wire made of different types of resin or metal without changing the stripper. Furthermore, in the case of a dissolving type stripper, since the resin is dissolved, there is no need to recover the resin portion, which is very convenient.
In a coating resin stripping treatment liquid that contains an oily component containing a higher aliphatic hydrocarbon and has an evaporation prevention layer disposed on the release treatment layer separately from the release treatment layer, the evaporation of the components contained in the coating resin stripping treatment liquid can be reduced, and therefore the treatment liquid can have less fluctuation in the treatment liquid component composition and can ensure stable performance even when used for a long time or repeatedly.
Furthermore, in the coating resin stripping treatment method using the coating resin stripping liquid or the coating resin stripping treatment liquid, the coating resin can be dissolved or swelled and stripped by simply immersing the insulated conductive wire in the stripping liquid or the stripping treatment liquid, so that the conductor wire can be exposed in a simple and inexpensive manner.
Furthermore, when the coating resin stripping solution remaining after the first coating resin stripping treatment method is carried out, after the first treatment, or after a further treatment, if any, is to be used continuously, the used stripping solution or the stripping treatment solution can be repeatedly used. Therefore, this is very convenient and very useful in terms of cost. In particular, the coating resin stripping treatment solution having an evaporation prevention layer is extremely useful for this repeated use, since it can reduce the fluctuation of the treatment solution component composition.
In addition, by using the coating resin remover or the coating resin remover treatment liquid, the conductor wire constituting the insulated conductive wire can be easily exposed by simply immersing the insulated conductive wire in the coating resin remover or the coating resin remover treatment liquid, without having to physically or mechanically strip the coating resin using large machinery or equipment, or without burning the resin. Therefore, by using the present remover, the exposed conductor wire can be recovered and easily reused. Furthermore, by using the present remover, the conductive wire can be easily reused regardless of the type of insulated conductive wire with a different coating resin or metal, without changing the remover. In addition, by using the present dissolving remover, the coating resin is dissolved, so there is no need to separate and recover the resin portion, and the conductive wire can be recovered very easily.
Furthermore, in the above method, the treatment temperature is set to 75 to 120° C., but is not limited thereto and can be set to about 80 to 110° C., 80 to 100° C., 80 to 98° C., 85 to 110° C., 85 to 100° C., or 85 to 98° C. In the case of a high temperature, the treatment time can be shortened, and in the case of a relatively low temperature, evaporation of the contained water can be reduced, and a stable composition can be maintained.

FIG. 2 is a diagram illustrating a treatment mode for dissolving a coating resin using the coating resin stripper of the present invention. FIG. 11 is a diagram illustrating the tip of the insulated conductive wire after the coating resin dissolving treatment. FIG. 2 is a diagram illustrating a magnet wire as an insulated conductive wire according to an embodiment. FIG. 2 is a diagram illustrating a single-type insulated conductive wire and a group-type insulated conductive wire as the insulated conductive wire.

The coating resin stripping solution of the present invention will now be described in more detail.
[Coating resin stripper]
The coating resin remover of the present invention (see coating resin remover L of the present embodiment shown in FIG. 1 ) is a coating resin remover L for removing coating resin 11 from insulated conductive wire 10 having conductor wire 12 and coating resin 11 coating conductor wire 12, and is characterized by containing an inorganic alkali (A), an alkanolamine (B) having 1 to 10 carbon atoms, and water (C).
Another coating resin stripper of the present invention is a coating resin stripper for stripping coating resin from an insulated conductive wire having a conductor wire and a coating resin coating the conductor wire, and is characterized in that it contains an alkanolamine (B) having 1 to 10 carbon atoms, water (C), and an aprotic polar solvent (D) having a boiling point of 100° C. or higher and having 2 to 6 carbon atoms.

The coating resin stripping solution containing the inorganic alkali (A), the alkanolamine (B) having 1 to 10 carbon atoms, and water (C) may further contain an aprotic polar solvent (D). The coating resin stripping solution containing the alkanolamine (B) having 1 to 10 carbon atoms, water (C), and the aprotic polar solvent (D) may further contain the inorganic alkali (A).
In addition, in the present coating resin remover L, each of the coating resin remover liquids L containing three components or each of the coating resin remover liquids L containing four components may further contain a predetermined alcohol-based solvent (E).
In the following, the inorganic alkali (A) will also be referred to as the "A component", the alkanolamine (B) as the "B component", the water (C) as the "C component", the aprotic polar solvent (D) as the "D component", and the alcohol solvent (E) as the "E component".

The type of insulated conductive wire 10 from which the coating resin 11 is removed using the coating resin stripping solution L of this embodiment is not particularly limited as long as it is an electric wire having a coating resin 11 covering a conductor wire 12. Examples of the insulated conductive wire 10 include electric power transmission wires, control and communication cables, and electric wires for various electric devices, and in particular, magnet wire 101a used for wiring and windings of inductors and motors for vehicles, etc., which is preferably small and has heat resistance to withstand current capacity.

The outer shape of the insulated conductive wire 10 is not particularly limited, and may be a round wire or a square wire. The insulated conductive wire 10 may be a standalone insulated conductive wire 101 consisting of a single insulated conductive wire 10 (see FIG. 4(c)), or may be an assembly type insulated conductive wire 102 including a plurality of insulated conductive wires 10 (see FIGS. 4(a) and 4(b)). If the insulated conductive wire is a standalone insulated conductive wire magnet wire 101a, a rectangular wire is often used as the conductor wire 12 in order to increase the occupancy rate of the winding (see FIG. 3).
When the insulated conductive wire is a grouped insulated conductive wire 102 or a single insulated conductive wire in the form of a rectangular wire such as the magnet wire 101a, these are usually special wire forms or shapes that make it difficult to physically peel off the coating resin using a peeling blade or laser beam. For example, in the case of the grouped insulated conductive wire 102, the insulated conductive wire is unwound into a single insulated conductive wire 10 and the coating resin is physically peeled off one by one, or in the case of the magnet wire 101a, a work of applying a peeling blade along the outer shape of the conductor wire that inevitably leaves an R shape at least at the corners is required. This coating resin stripping solution is particularly preferable when used for the coating resin stripping treatment of insulated conductive wires of these special wire forms or shapes, because the coating resin can be peeled off and easily removed by chemical action by immersing the insulated conductive wire in the coating resin stripping solution.

The material of the conductor wire is not particularly limited as long as it has conductivity for conducting electricity, and may be, for example, copper, aluminum, iron, platinum, silver, etc. The material of the conductor wire may be a single metal or an alloy, but copper and copper alloys are preferred from the viewpoint of conductivity, and aluminum and aluminum alloys are preferred from the viewpoint of weight reduction. The external shape of the conductor wire 12 is not particularly limited, and the cross-sectional shape may be a circular conductor wire (see FIG. 4), a rectangular conductor wire, or an indeterminate shape. The conductor wire may have a diameter of, for example, about 0.1 to 5 mm when converted into the equivalent circular cross-sectional shape.

There is no particular limitation on the type of coating resin 11. For example, the coating resin is preferably one having a hydrolyzable ester group, a urethane group, an amide group, or an imide group, among various groups.
Specifically, examples of the coating resin include polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, polybutylene naphthalate, unsaturated polyester, alkyd resin, and polyarylate; polyurethane-based resins such as thermoplastic polyurethane obtained by reacting a polyisocyanate compound with a polyol, polyester, epoxy, and polyurethane polyol compound, and thermosetting polyurethane crosslinked therewith; polyamide-based resins such as aliphatic nylons such as 6-nylon, 11-nylon, 12-nylon, 66-nylon, and 610nylon, and aromatic nylons such as MXD6-nylon; polycarbonate; polyacetal-based resins such as polyformal, polyvinyl formal, and polyvinyl butyral; polyether-based resins such as chlorinated polyether and polyphenylene ether; polysulfone resins; polyethersulfone resins; polyphenylene sulfite; polyimide-based resins; phenolic resins; epoxy resins; resins having an ester bond in the side chain such as diallyl phthalate and polyacrylate; and resins having an amide bond in the side chain such as polyformamide.
The coating resin may be a copolymer or graft polymer of the above-mentioned resins, and examples thereof include polyesterimide resin, polyesteramideimide resin, polyamideimide resin, and polyetherimide resin.
The coating resin may be a modified version of these, and is preferably one or more selected from these.

Among the above, the coating resin is preferably one or more selected from polyacetal resin, polyester resin, polyurethane resin, polyamide resin, polycarbonate, polyimide resin, polyesterimide resin, polyamideimide resin, and polyesteramideimide resin.

Among the above-mentioned preferred resins, it is particularly preferred if the coating resin is one or more selected from polyester resins, polyurethane resins, polyamide resins, polycarbonate resins, polyimide resins, polyesterimide resins, polyesterimide resins, polyamideimide resins, and polyesteramideimide resins. If the coating resin of the insulated conductive wire is one of these particularly preferred resins, it is suitable for insulated conductive wires that require heat resistance, and the coating resin can be dissolved and removed by a coating resin remover.

Among the above-mentioned preferred resins, it is particularly preferred that the coating resin is a polyacetal-based resin, and is one or more selected from polyformal, polyvinyl formal, and polyvinyl butyral. If the coating resin of the insulated conductive wire is one of these particularly preferred resins, it is suitable for use as an insulated conductive wire for magnet wire, which requires abrasion resistance during winding, and the coating resin can be dissolved or swelled and peeled off by a coating resin stripping solution.

Alternatively, the resin coating may be a double coating, such as an inner layer of polyesterimide overcoated with an outer layer of polyamideimide or polyamide.
The thickness of the coating resin is not particularly limited, but a coating film having a thickness of, for example, about 0.05 to 0.8 mm is preferably used as the target for peeling. The method for coating the conductor wire with the coating resin can be, for example, a dipping process by coating or an electrodeposition process by electrodeposition.

The components contained in the coating resin stripping solution L will be described in further detail below.
[Inorganic alkali (A)]
The inorganic alkali (A) may be any one that dissociates in water (C), and is preferably one that acts to promote the scission of the main chain. The inorganic alkali (A) is added as an alkali metal hydroxide or carbonate, etc., and is dispersed as ions in the coating resin stripping solution L. In this specification, the term "inorganic alkali" is used appropriately as a term that includes each state, such as an alkali metal hydroxide or carbonate, or an alkali ion state dispersed in the coating resin stripping solution L.
Specific examples of the inorganic alkali (A) include one or more selected from sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, etc. Among them, from the viewpoint of improving the releasability of the coating resin, one or more selected from potassium hydroxide, sodium hydroxide, sodium carbonate, and potassium carbonate are preferred, and at least one of sodium hydroxide and potassium hydroxide is particularly preferred.

The content of the inorganic alkali (A) is not particularly limited, but the upper limit can be 30% or less, preferably 25% or less, of the total amount of components A, B and C being 100% by mass (hereinafter simply referred to as %). If the content of component A exceeds 30%, care must be taken when handling the coating resin stripping solution L.
Furthermore, when the total amount of components A to D including component D is taken as 100%, the content of component A can be 30% or less, preferably 25% or less, as described above, but the upper limit can be 10% or less, preferably 5% or less, more preferably 4% or less, even more preferably 3% or less, and even more preferably 2% or less.
Generally speaking, a high content of inorganic alkali (A) can be advantageous for stripping the coating resin, but it is considered that this may have an effect on the conductor wire material that has a high ionization tendency. For this reason, it is preferable to keep the content of inorganic alkali (A) low, but it is not limited thereto, and it can be set to about 3% or less in particular so as not to sacrifice the stripping effect.

The content of component A may have a lower limit of 0.4% or more, preferably 0.5% or more, more preferably 0.8% or more, or 1% or more, or even 2% or more, whether it is a three-component composition of components A, B, and C, or a four-component composition including these and component D. If the lower limit of the content of inorganic alkali (A) is within this range, the amount of substance that cleaves the bond functional groups of the coating resin can be maintained, and the reaction that cleaves the bond functional groups can be promoted.

The content of the component A may be any combination of the upper and lower limits described above.
Particularly preferred combinations are those in the range of 1 to 30%, preferably 2 to 25%, for the three components, and 0.4 to 10%, more preferably 0.4 to 6%, even more preferably 0.5 to 4%, even more preferably 0.6 to 4%, even more preferably 0.8 to 3%, and even more preferably 0.8 to 2% for the four components.
A high content of the inorganic alkali (A) is preferred because the coating resin can be easily peeled off, whereas a low content of the inorganic alkali (A) is preferred because the effect on the metal can be reduced.

[Alkanolamine (B)]
The alkanolamine (B) having 1 to 10 carbon atoms in this embodiment is an amine having an alkane skeleton and a hydroxyl group bonded thereto, and is represented by the general formula [N.R1.R2.R3], where _R1 , _R2 , and _R3 are each independently hydrogen, _a linear or branched alkyl group having 1 to 6 carbon atoms, or a linear or branched alkyl alcohol having 1 to 6 carbon atoms _, and at least one of _R1 , _{R2 ,} and _R3 is an alkyl alcohol.
When the coating resin remover solution L contains an alkanolamine (B), it is believed that the cleavage action of ester groups, imide groups, amide groups, etc. is promoted, so that the clarity of the boundary between the remaining edge of the coating resin after dissolving the coating resin and the exposed conductor wire is more reliably maintained.

The alkanolamine (B) is not particularly limited, but is preferably a primary or secondary amine. _R1 , _R2 , and _R3 each represent at least one of hydrogen and an alkyl group. The number of carbon atoms in the alkyl alcohol is not particularly limited, but is preferably 6 or less, more preferably 4 or less, from the viewpoint of easy miscibility with water (C).
Specifically, the alkanolamine (B) is a primary alkanolamine [NH ₂ · R ₁ ] in which R ₁ is ethanol, which is monoethanolamine;
Similarly, secondary alkanolamines [NH·R ₁ ·R ₂ ] in which R ₁ is ethanol include N-methylethanolamine, N-propylethanolamine, N-isopropylethanolamine, N-butylethanolamine, N-(2-aminoethyl)ethanolamine and diethanolamine;
The same examples can be given below for cases where the alkyl alcohol is propanol, butanol, pentanol, hexanol, etc., and the alkanolamine (B) may be one or more selected from these.

Among these, the alkanolamine (B) is preferably one or more selected from monoethanolamine, diethanolamine, N-methylethanolamine, N-ethylethanolamine, N-butylethanolamine, N-(2-aminoethyl)ethanolamine, and N-(2-aminoethyl)propanolamine, and is particularly preferably monoethanolamine or diethanolamine.

The content of component B is not particularly limited, but can be 90% or less, preferably 60% or less, when the total of components A, B and C is taken as 100%.
In addition, when the composition contains components A, B, C and D, or further contains component E, the content of component B can be 50% or less, preferably 40% or less, and more preferably 38% or less, when the total content of these components is 100%. If the content of alkanolamine (B) exceeds 90%, the content of water (C) becomes relatively small, so that the inorganic alkali (A) tends to become difficult to dissolve in the coating resin stripper solution L, and by reducing the content of component B, the safety of handling the stripper solution can be improved.

The content of component B can be 30% or more, preferably 40% or more, when the total of components A, B and C is 100%.
When the composition contains components A, B, C and D, or further contains component E, the content of component B can be 10% or more, preferably 15% or more, and more preferably 20% or more. If the content of alkanolamine (B) is less than 10%, the amount of substance that contributes to cleavage of the bond functional group of the coating resin is thought to tend to decrease.

The content ratio of the B component can be any combination of the upper and lower limits described above, but a preferred combination is 30 to 90%, preferably 40 to 90%, when the total of the A component, B component, and C component is 100%. In addition, when the total of the A component, B component, C component, and D component is 100%, the content ratio of the B component can be 10 to 80%, 10 to 60%, preferably 10 to 50%, 10 to 40%, and more preferably 15 to 40%. In addition, when the total of the A component, B component, C component, D component, and E component is 100%, the content ratio of the B component can be 10 to 50%, preferably 15 to 40%, and more preferably 20 to 40%.
Furthermore, in either case where the composition contains components A, B, C, and D, or further contains component E, when the total of components A, B, C, and D is 100%, the content of component B can be 10 to 80%, preferably 10 to 60%, more preferably 15 to 60%, even more preferably 20 to 60%, even more preferably 10 to 50%, even more preferably 15 to 50%, and even more preferably 20 to 50%.

[Water (C)]
The type of water (C) is not particularly limited, and may be, for example, distilled water, tap water, or ion-exchanged water.
When the coating resin stripping solution L contains water, the inorganic alkali (A) can be quickly dissolved and dispersed in the treatment solution. In addition, the inclusion of water (C) is preferable because it is believed that the hydrolysis action of the inorganic alkali (A) and the alkanolamine (B) can be promoted. Although it depends on the type of coating resin, the inclusion of water (C) can contribute to shortening the time required for the coating resin stripping treatment to dissolve the coating resin by cutting the bond functional group in the alkaline aqueous solution.

The content of water (component C) is not particularly limited.
In the case of the A component, the B component and the C component, when the total of these is 100%, the upper limit of the content of the C component can be 50% or less, 40% or less, preferably 35% or less. In either case of the A component, the B component, the C component and the D component, or the E component, when the total of each of the four or five components is 100%, the upper limit of the C component content may be 40% or less, preferably 35% or less, 25% or less, 15% or less, more preferably 10% or less. When the water (C) is 40% or less, it is possible to achieve a balance with the content of the other components.

The content of water (C) may be such that the lower limit is 8% or more, preferably 10% or more, when the total of components A, B, and C is 100%. In either case where components A, B, C, and D are included, or where component E is further included, when the total of each of the four or five components is 100%, the lower limit of the content of component C may be 1% or more, preferably 2% or more, more preferably 3% or more, or may be 10% or more, or 20% or more.
The lower limit of the content of water (C) needs to be determined while considering the balance with the content of other components and the method of use of the coating resin stripping solution L. For example, when the content of inorganic alkali (A) in the coating resin stripping solution L is very low, 5% by mass or less, the content of water (C) may be about 2% by mass or more accordingly. In addition, when the coating resin stripping solution L is heated while the stripping treatment is performed, the boiling point of water (C) is relatively lower than that of other components, so that the content of water (C) is likely to change over time while the coating resin stripping solution L is repeatedly used. The content of water (C) exemplified above may be within the above range during treatment, and the content of water (C) before treatment (before heating) may be greater than the above value in anticipation of evaporation in advance.

The content of water (component C) in the coating resin stripping solution L can be any combination of the upper and lower limits mentioned above. A preferred combination is 8 to 40%, preferably 10 to 35%, when the total of components A, B, and C is 100%. Furthermore, when components A, B, C, and D, or even component E, are included, the content of component C can be 2 to 40%, preferably 2 to 35%, more preferably 2 to 25%, and even more preferably 2 to 15%, when the total of these components is 100%.

A preferred combination of the content ratios of the A component, the B component, and the C component is 1 to 30% for the A component, 30 to 90% for the B component, and 8 to 40% for the C component, and more preferably 2 to 25% for the A component, 40 to 86% for the B component, and 10 to 35% for the C component, when the total of the A component, the B component, and the C component is 100%.
When the combination of the inorganic alkali (A), alkanolamine (B) and water (C) is favorable as described above, the coating resin remover L functions favorably as a dissolving and stripping type coating resin remover that dissolves and strips a predetermined coating resin. Since the boundary between the edge of the coating resin that remains unstripped and the conductive wire exposed from the end of the coating resin is ensured, this can contribute to improving productivity in the work of chemically stripping the coating resin.

[Aprotic polar solvent (D)]
When the present coating resin stripping solution L contains an aprotic polar solvent (D), the aprotic polar solvent (D) preferably has a boiling point of 100° C. or higher, a carbon number in the range of 2 to 6, and is capable of dissolving and miscible with the inorganic alkali (A), the alkanolamine (B), and the water (C). The polarity and aprotic nature of the aprotic polar solvent (D) are specified based on a predetermined solubility parameter, i.e., the aprotic polar solvent (D) has a Hansen polarity parameter of 4.3 or higher, expressed in units of (cal/ml) 0.5, and a Hansen hydrogen bond parameter of 2.0 to 5.6.
When the coating resin remover L contains an aprotic polar solvent (D), it is considered that the degree of freedom of the agent (e.g., ^OH- ) acting nucleophilically on the functional group that is the bond portion connecting the repeating units of the coating resin is increased due to the solvation effect on the cation derived from the inorganic alkali (A). For example, if the coating resin is a polyimide resin, a polyimide amide resin, a polyester resin, or the like, it can support the cleavage of the bond portion of the imide group, amide group, ester group, or the like in the main chain, and the coating resin is quickly dissolved in the coating resin remover L, so that the time required for the highly heat-resistant coating resin removal treatment can be shortened, especially when the coating resin is dissolved and removed.

Here, the value of the Hansen solubility parameter (δ) is calculated based on dispersibility (δ _d ), polarity (δ _p ), and hydrogen bonding (δ _h ). The Hansen solubility parameter is usually expressed in units of either (MPa) ^0.5 or (cal/ml) ^0.5 , but in this specification, "(cal/ml) ^0.5 " will be used.
The parameter values of various solvents are disclosed on the Internet (http://www.stenutz.eu/chem/solv24.php?sort=1). Examples of aprotic polar solvents (D) having a boiling point of 100° C. or higher and specified based on the above parameter values include diethyl sulfate, dimethyl sulfoxide (hereinafter also referred to as "DMSO"), N,N-dimethylacetamide, N,N-dimethylformamide (hereinafter also referred to as "DMF"), N-methyl-2-pyrrolidone (hereinafter also referred to as "NMP"), 1,3-dimethyl-2-imidazolidinone (hereinafter also referred to as "DMI"), oxolan-2-one (γ-butyrolactone), thiolane-1-oxide, nitromethane, pyridine, and the like.
Specifically, the aprotic polar solvent (D) may be one or more selected from the above, preferably one or more selected from DMSO, NMP, DMF, and N,N-dimethylacetamide, each of which contains a nitrogen atom or a sulfur atom, and particularly preferably NMP, DMF, and DMSO.

When the aprotic polar solvent (D) is one or more selected from the above, it can gently peel or dissolve the coating resin and maintain the same dissolution time compared to a treatment solution consisting of only an aqueous alkali solution derived from inorganic alkali (A). In addition, the aprotic polar solvent (D) is preferable in that it is uniformly miscible with the aqueous inorganic alkali (A) solution and the alkanolamine (B) and that it has a relatively high boiling point of 100°C or higher, so that the dissolution rate of the coating resin can be increased by increasing the temperature during the peeling treatment.

The content of the aprotic polar solvent (D) is not particularly limited, but in the case of A component, B component, C component and D component, or in the case of further containing E component, when the total of these components is 100%, it can be 80% or less, preferably 60% or less, and can be 40% or less. Furthermore, in the case of A component, B component, C component and D component, or in the case of further containing E component, when the total of these components is 100%, the content of this D component can be 10% or more, preferably 20% or more, more preferably 25% or more, and more preferably 28% or more. The upper and lower limits can be used in appropriate combination.
The content of the aprotic polar solvent (D) contained in the coating resin stripping solution L is determined from the viewpoint of miscibility with other components and other solvents, and the speed of gently stripping the coating resin. If the content of the aprotic polar solvent (D) in the coating resin stripping solution L is too high, the balance with the content of other components will be poor when stripping a coating resin having a bond functional group with low reactivity with a nucleophile. If the content of the aprotic polar solvent (D) is too low, the effect of gently and quickly stripping the coating resin will be difficult to obtain when stripping a coating resin having a bond functional group with high reactivity with a nucleophile. Depending on the bond functional group of the coating resin, the reactivity of the functional group with the nucleophile may be high or low, so by appropriately balancing the content of the aprotic polar solvent (D), the versatility of the coating resin stripping solution L corresponding to various coating resins can be improved.

The content ratio of the D component can be any combination of the upper and lower limits mentioned above, but preferred combinations are 20 to 80%, preferably 25 to 80%, when the total of A, B, C and D components, or B, C and D components, is taken as 100%, and can also be 20 to 60%, 25 to 60%, 20 to 40%, 25 to 40%, or 28 to 40%.

Furthermore, when the total of components A, B, C, D and E is 100%, the content of component D can be 25 to 35%, preferably 25 to 28%.

A preferred combination of the content ratios of each of the A, B, C and D components is, when the total of the A, B, C and D components is 100%, the A component is 0.5 to 8%, the B component is 10 to 80%, the C component is 2 to 40%, and the D component is 15 to 80%, preferably the A component is 0.8 to 6%, the B component is 15 to 75%, the C component is 2 to 35%, and the D component is 15 to 77%, more preferably the A component is 0.8 to 5.5%, the B component is 20 to 70%, the C component is 2 to 30%, and the D component is 20 to 77%, and even more preferably the A component is 0.8 to 4%, the B component is 20 to 70%, the C component is 2 to 20%, and the D component is 20 to 60%.
If the combination of the content ratios of inorganic alkali (A), alkanolamine (B), water (C) and aprotic polar solvent (D) is favorable, the coating resin stripper L acts favorably as a dissolving and stripping type coating resin stripper that dissolves and strips a specific coating resin. For example, if the coating resin is a polyimide resin, a polyimide amide resin, a polyester resin, etc., the aprotic polar solvent (D) in the coating resin stripper L can support the bond scission action of imide groups, amide groups, ester groups, etc. in the main chain by alkaline hydrolysis, and dissolve the coating resin in the coating resin stripper L quickly and gently, so that the time required for the stripping treatment of these high heat-resistant coating resins can be shortened, especially when dissolving and stripping the coating resin. Therefore, it can further contribute to improving productivity in the work of chemically stripping the coating resin.

As a particularly preferred combination of the content ratios of the A component, the B component, the C component, and the D component, there may be a case where the contents of the A component and the C component are low. In this case, when the total of the A component, the B component, the C component, and the D component is taken as 100%, among these components, the A component can be 0.5 to 5%, the B component can be 15 to 50%, the C component can be 2 to 12%, and the D component can be 20 to 80%, preferably the A component can be 0.8 to 3%, the B component can be 15 to 40%, the C component can be 2 to 10%, and the D component can be 25 to 80%, and more preferably the A component can be 0.9 to 2%, the B component can be 22 to 40%, the C component can be 2 to 8%, and the D component can be 25 to 45%.
When the combination of the content ratios of components (A) to (D) among components (A) to (D) falls within the above range, the content ratio of the inorganic alkaline aqueous solution in the coating resin stripping solution L can be kept low, and therefore coating resin stripping treatment can be preferably performed on insulated conductive wires using conductor wire materials with a high ionization tendency (e.g., aluminum). Furthermore, the coating resin stripping solution L acts preferably as a dissolution-type stripping treatment solution, and can rapidly and gently strip heat-resistant coating resins such as polyimide, polyamideimide, and polyesterimide in addition to polyester.
A preferred combination of the content ratios of each of the B, C and D components is 15 to 70% for the B component, 3 to 20% for the C component and 20 to 80% for the D component, preferably 15 to 65% for the B component, 4 to 18% for the C component and 20 to 80% for the D component, when the total of the B, C and D components is 100%.

[Alcohol-based solvent (E)]
The alcohol-based solvent (E) of the present embodiment is not particularly limited, but is preferably at least one of a linear or branched alcohol having a boiling point of 100° C. or higher and a mono- to trivalent linear or branched alcohol having 2 to 6 carbon atoms and a mono- to trivalent aromatic alcohol having 2 to 8 carbon atoms.
When the coating resin remover L contains an alcohol-based solvent (E), it is believed that the reaction causing the conductor wire to dissolve can be suppressed compared to water (C) when the material of the conductor wire has high reactivity with an aqueous solution of inorganic alkali (A).
In addition, when a coating resin containing a functional group (e.g., ether) at a bond portion that has a relatively low reactivity with a nucleophile is peeled off, the coating resin can be swelled by the solvation effect due to the hydrogen bonding action of the alcohol-based solvent (E) and peeled off so as to separate it from the surface of the conductor wire. When a coating resin having a bond functional group that has a high reactivity with a nucleophile is peeled off, the resin can be dissolved and peeled off, and the peeling can be performed by swelling without necessarily relying on dissolution and peeling, so that the versatility of the coating resin peeling solution L that can be used for various coating resins can be improved.

Specifically, when the alcohol-based solvent (E) is a linear or branched alcohol, examples of the alcohol-based solvent include 2-methoxyethanol (methyl cellosolve), 2-ethoxyethanol (ethyl cellosolve), 1-methoxy-2-propanol, 3-methoxy-1-propanol, 1,2-propanediol (propylene glycol), 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2,3-propanetriol, diethylene glycol, ethylene glycol, triethylene glycol, and the like;
Aromatic alcohols include benzyl alcohol, methylbenzyl alcohol, benzenedimethanol, and methylbenzyl alcohol;
When the aromatic alcohol has a phenol skeleton, examples thereof include phenol, dihydroxybenzene, trihydroxybenzene, methoxyphenol, dimethoxyphenol, ethoxyphenol, methylphenol (cresol), dimethylphenol, ethylphenol, methylresorcinol, ethylresorcinol, methyltrihydroxybenzene, and ethyltrihydroxybenzene.

The alcohol-based solvent (E) may be one or more selected from the above, but is preferably one or more selected from propylene glycol, diethylene glycol, ethylene glycol, triethylene glycol, phenol, catenal, phloroglucinol, cresol, and benzyl alcohol, with 2-methoxyethanol, propylene glycol, ethylene glycol, phenol, and benzyl alcohol being particularly preferred.

The content of the alcohol solvent (component E) is not particularly limited, but when the total of components A, B, C, D and E is taken as 100%, the upper limit can be 50% or less, 45% or less, and preferably 40% or less. The lower limit of the content of component E can be 5% or more, preferably 10% or more, and more preferably 18% or more. Any combination of the upper and lower limits can be used.
If the content of the alcohol-based solvent (E) is less than the lower limit, the proportion of the alkaline aqueous solution component becomes relatively large, and as a result, depending on the material of the conductor wire, the eluted product may remain on the surface of the conductor wire after the stripping treatment, which may increase the contact resistance. If the content of the alcohol-based solvent (E) is more than the upper limit, the proportion of the alkaline aqueous solution component becomes relatively small, and as a result, the stripping effect may be suppressed for the coating resin that is decomposed by the alkaline aqueous solution.

The content ratio of the alcohol-based solvent (E) in the coating resin stripping solution L may be any combination of the upper and lower limits described above. A preferred combination is, when the total of the components A, B, C, D and E is taken as 100%, 5 to 50 mass %, preferably 10 to 45 mass %, and more preferably 18 to 40 mass %.
In addition, when a coating resin that corresponds to 100% of the total mass of the five components A to E and has a bonding functional group with low reactivity with a nucleophilic agent is used for the peel treatment, the range can be about 23 to 32%.

A preferred content ratio of component E is 10 to 80 parts by mass, preferably 20 to 80 parts by mass, and more preferably 20 to 70 parts by mass, when the total mass of components A to D having the above-mentioned preferred content ratio combination is 100 parts by mass.
In the above case, even if the material of the conductor wire is reactive to the aqueous solution of the inorganic alkali (A), the conductor wire can be prevented from dissolving in the coating resin stripper. Moreover, the coating resin stripper L preferably functions as a dissolution stripping type stripper that dissolves and strips a predetermined type of coating resin, and also preferably functions as a swelling stripping type stripper that mainly swells and strips other predetermined types of coating resin.
Alternatively, from the viewpoint of the versatility of the coating resin stripping solution L corresponding to various coating resins, the particularly preferred content ratio of the alcohol-based solvent (E) can be 24 to 52%, preferably 26 to 50%, and more preferably 28 to 48% relative to the total mass of the components A to D having the above-mentioned preferred content ratio combination of 100%. In this case, the coating resin stripping solution L specifically acts as a dissolution stripping type stripping solution for polyester, polyamideimide, and polyimide coating resins, and can also act as a swelling stripping type stripping solution for polyvinyl formal coating resins, which mainly swells and strips the resin. The versatility of the coating resin stripping solution L corresponding to these coating resins is reliably improved, and this can contribute to further improving productivity in the work of chemically stripping the coating resin.

(Other ingredients)
In addition to the above-mentioned components, the coating resin stripping solution L may contain an organic acid or an inorganic acid, and preferably an organic acid. Preferred organic acids include formic acid, phenol, and phenolic compounds having multiple hydroxyl groups (e.g., phloroglucinol). Examples of inorganic acids include phosphoric acid and methanesulfonic acid.
When the coating resin stripper L contains an organic acid, even if the coating resin does not necessarily have a bond functional group that is highly reactive with a nucleophile, it can help the coating resin to be peeled off while swelling. In this case, the versatility of the coating resin stripper L for various coating resins can be further improved. In addition, when the coating resin stripper L contains the organic acid or inorganic acid, especially the organic acid, it is effective in stripping polyacetal resins (polyformal, polyvinyl formal, polyvinyl butyral, etc.). In addition, a stripper containing 100% formic acid and phenol can strip polyacetal resins by itself.

In addition to the above-mentioned components, the coating resin remover L may also contain a conductor wire corrosion inhibitor and a surfactant. For example, if the conductor wire is made of copper, a corrosion inhibitor such as benzotriazole can be used, and if the conductor wire is made of aluminum, a corrosion inhibitor such as Killesvit AL can be used. Examples of surfactants include anionic, nonionic, cationic, and amphoteric surfactants, of which nonionic surfactants are preferred.

[Treatment solution for peeling off coating resin]
The coating resin stripping treatment liquid _L0 is prepared using the above-mentioned coating resin stripping liquid L, as shown in Fig. 1. The coating resin stripping treatment liquid _L0 is characterized by having a release treatment layer _L1 containing the coating resin stripping liquid L, and an evaporation prevention layer _L2 containing an oily component (F) containing a higher aliphatic hydrocarbon and disposed on the release treatment layer _L1 separately from the release treatment layer _L1 . The coating resin stripping treatment liquid _L0 is obtained by mixing the coating resin stripping liquid L with the oily component (F).

The release treatment layer _L1 is mainly composed of the coating resin stripping solution L, and forms a polar solvent phase containing the above-mentioned respective stripping components. That is, the release treatment layer _L1 contains at least inorganic alkali (A), alkanolamine (B), and water (C) as stripping components, and preferably contains aprotic polar solvent (D) and alcohol-based solvent (E) in the same phase. The content of the coating resin stripping solution L in the release treatment layer _L1 may be almost 100%.

The evaporation-preventive layer _L2 forms a non-polar solvent phase mainly composed of an oily component (F) containing a higher aliphatic hydrocarbon. The content of the oily component (F) in the evaporation-preventive layer _L2 may be approximately 100%. The evaporation-preventive layer _L2 is provided to prevent the evaporation of the above-mentioned release components (A) to (E) in the release treatment layer _L1 when the coating resin stripping treatment liquid _L0 is heated for use, or to clearly define the boundary between the edge of the coating resin that remains unpeeled after treatment and the conductive wire exposed from the end of the coating resin.
The oily component (F) is, for example, a higher aliphatic hydrocarbon having 20 or more carbon atoms that is liquid at room temperature, non-volatile, and insoluble in water. Specific examples include oils collectively known as liquid paraffin, such as white oil, white mineral oil, and mineral oil.

The coating resin peeling treatment liquid _L0 is provided with an evaporation prevention layer _L2 in which the oily component (F) is disposed on the upper surface of the peeling treatment layer _L1 so as to seal the upper surface (see the liquid surface S of the coating resin peeling liquid L in FIG. 1) and prevents evaporation of the peeling components. Since the evaporation of water (C), which has a particularly low boiling point among the peeling components of the peeling treatment layer _L1 , can be prevented, even when the coating resin peeling treatment liquid _L0 is heated and used for peeling treatment of the coating resin, the water (C) can be prevented from decreasing in volume. The coating resin dissolving ability and swelling ability of the coating resin peeling liquid L are maintained, and it is not necessary to frequently add the peeling component each time a peeling treatment is performed, and the coating resin peeling treatment liquid _L0 can be used repeatedly as it is, which is preferable in that the safety of the working environment is improved.

In the coating resin peeling treatment liquid _L0 , the mass ratio of the release treatment layer _L1 to the evaporation prevention layer _L2 may be about 0.5 to 15, preferably about 0.7 to 10, and more preferably about 0.9 to 8 _, per 100 of the release treatment layer _L1 . If the proportion of the evaporation prevention layer _L2 is less than the lower limit, the evaporation prevention effect or boundary clarification effect may be suppressed, and if it is more than the upper limit, the oily stickiness may be emphasized, and the handleability of the coating resin peeling treatment liquid _L0 may be impaired.

[Method for dissolving coating resin or method for dissolving coating resin in a method for recycling conductor wire]
As shown in FIG. 1 and FIG. 2, the method of dissolving the coating resin 11 of the insulated conductive wire 10 using the above-mentioned coating resin remover L can be carried out, for example, as follows:
1) The coating resin remover L is heated to 75° C. or higher and 120° C. or lower, and a portion (usually the tip) of the insulated conductive wire 10 covered with the coating resin 11 is immersed in the coating resin remover L.
2) The immersion time should be no more than 30 minutes.
3) The coating resin 11 is dissolved by immersion in the coating resin remover L. 4) The conductor wire 12 covered with the coating resin 11 is exposed.
5) The insulated conductive wire 10 is removed from the coating resin remover L.
The removed insulated conductive wire 10 can be used without the need to wipe off any remaining melted resin components from the exposed portion of the conductor wire 12 (see the conductor wire tip 12a in FIG. 2).

When heating the coating resin stripping solution L (or the coating resin stripping treatment solution L ₀ ), the lower limit of the temperature of the coating resin stripping solution L can usually be 75° C. or higher, preferably 80° C. or higher, and more preferably 85° C. or higher. Similarly, the upper limit can be set to 120° C., 110° C., 100° C. or lower, 98° C. or lower, 97° C. or lower, or 95° C. or lower, depending on the purpose, desired effect, and application. The treatment temperature can be various combinations of the lower and upper limits. If the temperature of the coating resin stripping solution L is within the preferred range, it is possible to prevent thermal deterioration of the coating resin stripping solution L due to heating while shortening the immersion time for stripping the insulated conductive wire 10 in the coating resin stripping solution L. For example, the temperature of the coating resin stripping solution L can be 80 to 110°C, 80 to 100°C, 80 to 98°C, 80 to 97°C, 85 to 110°C, 85 to 100°C, 85 to 98°C, 85 to 97°C, 90 to 110°C, 90 to 100°C, 90 to 98°C, or 90 to 97°C. In the above case, the coating resin 11 can be dissolved and stripped or swollen and stripped within an immersion time of 20 to 30 minutes, particularly within 20 minutes. Note that a higher temperature of the coating resin stripping solution L can shorten the treatment time, and a lower temperature of the coating resin stripping solution L can increase the number of times the coating resin stripping solution L is used repeatedly, although the treatment time is longer. Furthermore, when the treatment temperature is set to a higher temperature of 85 to 120° C., 85 to 110° C., 90 to 120° C., 90 to 110° C., 95 to 120° C., or 95 to 110° C., the treatment time can be set to about 5 to 20 minutes, or further to about 5 to 15 minutes.

(Anti-transpiration layer)
In the present coating resin dissolving treatment method, preferably, a water evaporation prevention layer _L2 containing the above-mentioned oily component (F) containing higher aliphatic hydrocarbon may be provided on the coating resin stripping liquid L (see FIG. 1). That is, the coating resin stripping treatment liquid _L0 may be prepared in advance and directly heated before the stripping treatment is started, or the oily component (F) may be added to the coating resin stripping liquid L when the stripping treatment is performed. In the coating resin dissolving treatment method, the timing of providing such an evaporation prevention layer is not particularly limited, but it is preferable that it is provided before heating the coating resin stripping liquid L in order to prevent water evaporation as much as possible. Note that, once the evaporation prevention layer is provided on the coating resin stripping liquid L, there is no need to add the oily component (F) each time the coating resin stripping liquid L is used repeatedly thereafter. That is, after the first coating resin stripping treatment method is performed, the coating resin stripping liquid L remaining after the first treatment may be used continuously.
In this manner, the coating resin stripping method of the present invention can contribute to improving the productivity of removing coating resin using a treatment solution for chemically stripping the coating resin from an insulated conductive wire.

In addition, in the present coating resin stripping method, even when the conductor wires are made of different materials and the types of coating resins are different, one type of coating resin stripping solution L may be used. Thus, the present coating resin stripping method can contribute to improving the productivity of removing coating resins in a treatment solution for chemically stripping the coating resin of an insulated conductive wire.
Examples of the different conductor wire materials include copper, copper alloys, aluminum, and aluminum alloys. A plurality of insulated conductive wires using conductor wires made of different materials selected from among these may be subjected to the stripping treatment at the same time.
Examples of different types of coating resins include polyacetal-based resins, polyester-based resins, polyurethane-based resins, polyamide-based resins, polyether-based resins, polyimide-based resins, polyesterimide resins, polyesteramideimide resins, polyamideimide resins, and polyetherimide resins. A plurality of insulated conductive wires using one coating resin selected from these may be subjected to the stripping treatment at the same time.

The following describes an embodiment of the present invention.
[Test Example A]
In this test example, tests were carried out using the stripping solution shown in Table 1 according to the test method described below, and the test results are shown in Table 2.
(Insulated Conductive Wire 10)
First, as shown in Fig. 1, a rectangular insulated conductive wire 10 was prepared in which the circumferential surface of a conductor wire 12 was covered with a coating resin 11 containing at least an imide group or an ester group in the repeating unit. The shape of the insulated conductive wire 10 was roughly similar to the outer shape of the conductor wire 12, and the cross section of the conductor wire 12 was roughly rectangular with a pair of rounded short sides 121r that bulged out slightly in an arc.
Two types of materials, copper and aluminum, were used as the material for the conductor wire 12. Three types of materials, polyamide-imide resin, polyester resin, and polyimide resin, were used as the material for the coating resin 11. The thickness of each coating resin 11 was about 0.5 (mm).
As shown in FIG. 3, the insulated conductive wire 10 is wound edgewise to be used as a magnet wire 101a, and a predetermined length was cut out in the longitudinal direction to be used for the evaluation test of this embodiment.

(Coating resin remover L)
Next, the following components were used to make up the coating resin stripping solution. Component (A) KOH was prepared as a 48% by mass aqueous solution. Component (B) monoethanolamine contained 10% by mass of water in advance. Phosphoric acid contained 15% by mass of water in advance. The following components were added and mixed to prepare coating resin stripping solutions L Nos. 1 to 14. The components contained in each coating resin stripping solution L and their content ratios are shown in Table 1.
(1) Inorganic alkali (A):
K.O.H.
(2) Alkanolamines (B):
Monoethanolamine (MEA)
(3) Water (C):
The water (C ₀ ) contained in advance in the KOH aqueous solution, the phosphoric acid aqueous solution and the monoethanolamine, and the added water (C ₁ ) added separately to the coating resin stripping solution L are included.
(4) Aprotic polar solvent (D):
N-Methylpyrrolidone (NMP)
Dimethyl sulfoxide (DMSO)
(5) Alcohol-based solvent (E):
Propylene glycol (PG)
Benzyl alcohol (BzA)
(6) Oil-like component (F):
MORESCO White (Made by MORESCO)
(7) Aluminum corrosion inhibitor: Killesvit AL (manufactured by Killest Co., Ltd.)
(8) Organic acids: Phosphoric acid

(Method of dissolving coating resin)
As shown in Fig. 1, each of the coating resin stripping solutions L Nos. 1 to 14 obtained as described above was poured into a container, immersed in a pre-temperature-adjusted oil bath, heated to 95°C, and maintained at that temperature. In this case, for the coating resin stripping solutions L Nos. 4, 7 to 10, and 13, "1" of Moresco White was added to "100" of the coating resin stripping solution L before heating. Then, one end of the insulated conductive wire 10 (corresponding to the symbol 11a in Fig. 1) was immersed in each of the coating resin stripping solutions L Nos. 1 to 14 in the container that had been left stationary. The insulated conductive wire 10 was immersed in each of the coating resin stripping solutions L Nos. 1 to 14 in the container that had been left stationary for a maximum of one hour until the coating resin tip 11a in contact with each coating resin stripping solution L was peeled off.

(Removability evaluation)
The state of the tip 11a of the coating resin immersed in the coating resin stripping solution L of Nos. 1 to 14 until it was peeled off was observed, and the peelability of the coating resin was evaluated as follows.
<Immersion time required for peeling treatment>
After the coating resin tip 11a was peeled off, the boundary between the exposed conductor wire tip 12a and the edge 11b of the coating resin 11 was clear as shown in Fig. 2, and the coating resin tip 11a was removed in a peeling manner in which it dissolved in the coating resin remover L. The immersion time required for the coating resin dissolution treatment until "dissolution peeling" was achieved was evaluated based on the following criteria. Table 3 shows the results of the evaluation of peelability when the coating resin peeling treatment was performed, with the cases using the coating resin remover L Nos. 1 to 11 being Examples 1 to 11 and the cases using the coating resin remover L Nos. 12 to 14 being Comparative Examples 1 to 3.

⊚: "Dissolution peeling" or "swelling peeling" occurred within 30 minutes of immersion. ◯: "Dissolution peeling" or "swelling peeling" occurred within 1 hour of immersion. ×: The coating resin could not be removed even after immersion for more than 1 hour.

As shown in Table 2, it was found that in Examples 1 to 11, which used coating resin stripping solution L Nos. 1 to 11, each coating resin 11 of the insulated conductive wire 10 could be dissolved and stripped off. As shown in Table 1, the coating resin stripping solution L Nos. 1 to 11 contained KOH as the inorganic alkali (A), monoethanolamine as the alkanolamine (B), and water (C). In contrast, the coating resin stripping solution L No. 12 contained phosphoric acid instead of the inorganic alkali (A) and the alkanolamine, and the coating resin stripping solution L Nos. 13 and 14 did not contain the inorganic alkali (A). As a result, it was found that the coating resin stripping solution L Nos. 12 to 14 was used in Comparative Examples 1 to 3, which did not have the ability to dissolve the coating resin 11.

According to Examples 1 to 11, if the coating resin 11 contains functional groups such as ester groups, amide groups, and imide groups as bonds connecting the repeating units, the coating resin 11 immersed in the coating resin remover L is hydrolyzed by the inorganic alkali (A) that dissolves in water (C) as well as the alkanolamine (B) to cut the bonds in the main chain, reduce the molecular weight, and even lead to decomposition. For the polyamideimide, polyester, and polyimide coating resins 11 of Examples 1 to 11, the coating resin remover L is thought to act as a dissolving and removing type. In this way, in Examples 1 to 11, the coating resin 11 is not peeled off by weakening the interaction between the coating resin 11 and the surface of the conductor wire 12 while swelling the coating resin 11, so the shape of the edge 11b of the coating resin 11 that was not immersed in the coating resin remover L remains horizontal along the contact line SL with the liquid surface S of the coating resin remover L (see Figures 1 and 2), and a clear boundary between the conductor wire tip 12a exposed after the coating resin is dissolved and the edge 11b of the remaining coating resin 11 is more reliably maintained. The original coating resin tip 11a did not remain dissolved on the surface of the conductor wire tip 12a, or rose up in a spotty uneven shape from the surface of the conductor wire tip 12a while swelling. Since there was no need to remove these, the productivity of the coating resin peeling process could be increased in the work of chemically removing the coating resin 11 from the insulated conductor wire 10.

Specifically, when the coating resin 11 was stripped using the coating resin stripper L of this embodiment, a portion of the insulated conductive wire 10 was immersed in the coating resin stripper L at 95°C, and the tip 11a of the coating resin was dissolved within an immersion time of 20 minutes, exposing the tip 12a of the conductor wire.

The insulated conductive wire 10 according to this embodiment is a magnet wire 101a, and the conductor wire 12 is a rectangular wire like the magnet wire 101a.
Therefore, the solubility in the coating resin stripping solution could be adjusted by specializing in a resin with a composition suitable for the coating resin application of magnet wire. Since polyimide-based resins such as polyimide and polyamide-imide and polyester-based resins have different skeletons and compositions according to various applications, it is considered that the stripping properties in the coating removal treatment solution also differ for each composition according to the application. For example, the compositions of polyimide-based resins and polyester-based resins used as coating resins for magnet wires are special in that they should be suitable for specific required physical properties such as flexibility to withstand the winding work of the wire and resistance to stress caused by the difference in thermal expansion with the conductor wire, and the coating resin stripping solution L suitable for this could be adjusted.
Furthermore, even if the insulated conductive wire was a rectangular wire, a typical conductor shape that is difficult to physically strip using a stripping blade or laser beam, the insulating coating could be easily removed by chemically dissolving the coating resin.

[Test Example B]
In this test example, the stripping solution shown in Table 3 was used and the test was carried out in the same manner as in Test Example A. The test results are shown in Table 4.
(Insulated Conductive Wire 10)
An insulated conductive wire 10 similar to that of Test Example A was used, except that a total of three types of coating resins were tested, namely, polyamideimide resin, polyester resin, and polyvinyl formal resin, using polyvinyl formal resin instead of polyimide resin, as the material for the coating resin 11.

(Coating resin stripping liquid L, coating resin stripping treatment liquid _L0 )
The following were also used as components constituting the coating resin stripping solution L. Namely, coating resin stripping solutions L Nos. 15 to 25 were prepared in the same manner as in [Test Example A], except that phenol and phloroglucinol were used as the alcohol-based solvent (E) and formic acid was used. The components contained in each coating resin stripping solution L and their content ratios are shown in Table 3.
(1) Alcohol-based solvent (E):
Phenol Phloroglucinol (2) Organic acid Formic acid

(Coating resin peeling treatment liquid _L0 )
The same oily component (F) as in [Test Example A] was added to each of the coating resin stripping solutions L of No. 18 to 20, and coating resin stripping treatment solutions _L0 of No. 18 to 20 were prepared, each having a release treatment layer _L1 containing the coating resin stripping solution L and an anti-transpiration layer _L2 containing the oily component (F) and disposed on the release treatment layer _L1 separately from the release treatment layer _L1 (see FIG. 1). In each coating resin stripping treatment solution _L0 , the release treatment layer _L1 was the coating resin stripping solution L, and the anti-transpiration layer _L2 was the oily component (F). The mass ratio of the coating resin stripping solution L:Moresco White was "6" to "100" of each of the coating resin stripping solutions L of No. 18 to 20, and was the same for each. In the following, the "coating resin stripping treatment solution L0" of No. 18 to 20 will be appropriately referred to as the "coating resin stripping treatment solution _L0 " of each No. This is also referred to as "coating resin stripping solution L."

(Method of Coating Resin Peeling Treatment)
[Test Example A] Similarly, the coating resin stripping treatment was performed. That is, the coating resin stripping solutions L of Nos. 15 to 25 (or the coating resin stripping treatment solutions L ₀ of Nos. 18 to 20) were heated to 95°C and maintained at that temperature. In the cases of Test Examples 21-4 and 24-1, the heating temperature was 100°C. The insulated conductive wire 10 was immersed in each coating resin stripping solution L for a maximum of one hour until the coating resin tip portion 11a in contact with the coating resin stripping solution L was stripped off.

(Removability evaluation)
The state of the tip 11a of the coating resin immersed in the coating resin stripping solution L of Nos. 15 to 25 until it was peeled off was observed, and the peelability of the coating resin was evaluated as follows.
1. Peeling Mode
After the coating resin 11 was peeled off, the following was determined as "dissolution peeling" in the same manner as in [Test Example A]: the boundary between the exposed conductor wire tip 12a and the edge 11b of the coating resin 11 was clear and the coating resin tip 11a was dissolved in the coating resin remover L and removed; the boundary between the exposed conductor wire tip 12a and the edge 11b of the coating resin 11 was clear and the coating resin 11 was peeled off by swelling in the coating resin remover L and rising up from the surface of the conductor wire. The time required for the coating resin dissolution treatment to reach "dissolution peeling" and "swelling peeling" was evaluated based on the following criteria. The cases where coating resin remover L Nos. 15 to 20 were used were designated Test Examples 15 to 20, and the cases where coating resin remover L Nos. 21 to 25 were used were designated Test Examples 21 to 25. The results of the peelability evaluation performed for the coating resin peeling treatment are shown in Table 4.

⊚: "Dissolution peeling" occurred within 30 minutes of immersion. ⊚ ^* : "Swelling peeling" occurred within 30 minutes of immersion. ◯: "Dissolution peeling" or "swelling peeling" occurred within 1 hour of immersion. ×: The coating resin could not be removed even after immersion for more than 1 hour.

As shown in Table 4, in test examples 15 to 20 using coating resin stripping solution L No. 15 to 20, it was found that the coating resin 11 of the insulated conductive wire 10, which is polyamideimide, polyester, and polyvinyl formal, can be dissolved and swelled to be stripped. As shown in Table 3, the coating resin stripping solution L No. 15 to 20 contained KOH as the inorganic alkali (A), monoethanolamine as the alkanolamine (B), water (C), NMP as the aprotic polar solvent (D), and benzyl alcohol or phenol as the alcohol solvent (E).

According to Test Examples 15 to 20, if the bonding functional group of the coating resin 11 is polyamideimide or polyester containing any one of an ester group, an amide group, or an imide group, it is considered that, similarly to [Test Example A], the bonding portion in the chain of the coating resin 11 immersed in the coating resin remover solution L is hydrolyzed by the inorganic alkali (A) dissolved in the water (C) as well as the alkanolamine (B), resulting in a decrease in molecular weight and even decomposition.
If the coating resin 11 is polyvinyl formal and the binding functional group includes an acetal group obtained by condensing an alcohol with an aldehyde under an acid catalyst, the acetal group is considered to return to the original aldehyde and alcohol in the presence of water (C) or a mild acid. When the polyvinyl formal returns to the original alcohol and aldehyde, solvation by the water (C) or the alcohol-based solvent (E) in the coating resin remover L proceeds, and the coating resin is considered to be peeled off from the surface of the conductor wire while breaking the chain, and can be "swelled and peeled off". It is considered that the coating resin remover L acts as a swelling peeling type for the polyvinyl formal coating resin 11 of the test examples 15 to 20. In fact, the polyvinyl formal coating resin did not peel off in a spotty uneven manner by swelling and rising from the surface of the conductor wire tip 12a.

From Test Example 21, it was found that the coating resin stripping solution L of No. 21 containing KOH, MEA and water in the indicated content ratio acts as a "dissolution stripping type" for the coating resins which are polyamideimide and polyester.
From Test Example 22, it was found that the coating resin stripping solution L of No. 22 containing KOH, MEA, water, NMP, BzA and phenol (46.2 mass%) in the indicated content ratios acts as a "dissolution stripping type" for coating resins that are polyester and polyvinyl formal, and can act as a "dissolution stripping type" for coating resins that are polyamideimide.
From Test Example 23, it was found that coating resin stripper L of No. 23 containing KOH, MEA, water, NMP, BzA and phenol (10.0 mass%) in the indicated content ratios acts as a "dissolution stripping type" for polyester coating resins, acts as a "swelling stripping type" for polyvinyl formal coating resins, and can act as a "dissolution stripping type" for polyimide amide coating resins.
From Test Example 24, it was found that the coating resin stripping solution L of No. 24 containing KOH, MEA, water, NMP, BzA and phloroglucinol (24.6% by mass) in the indicated content ratio acts as a "swelling stripping type" for the coating resin which is polyvinyl formal, and is difficult to strip for the coating resin which is polyimide amide.
From Test Example 25, it was found that coating resin stripper L No. 25 containing 100% by mass of formic acid acts as a "swelling stripper" against the coating resin which is polyvinyl formal, and is difficult to strip against the coating resin which is polyimide amide. In addition, the stripper containing only phenol (No. 26) also acted as a "swelling stripper" against the coating resin which is polyvinyl formal (Test Example 26).
In general, the coating resin remover L of each of Test Examples 21 to 25 tended to act as a "dissolution stripping type" when the coating resin was polyamideimide or polyester, and as a "swelling stripping type" when the coating resin was polyvinyl formal, and it was found that the coating resin remover L was capable of stripping any of polyamideimide, polyester, and polyvinyl formal.

As described above, from Test Example 21, if the coating resin is polyamideimide or polyester, these resins are dissolved and stripped by the coating resin stripper L of No. 21 containing each of the components (A) to (C). On the other hand, it is found that the coating resin stripper L of No. 21, which does not contain the aprotic polar solvent (D) and the alcohol solvent (E), has difficulty in dissolving and swelling the coating resin of polyvinyl formal. From separate experimental confirmation, it has been found that polyvinyl formal shows no signs of peeling in a 100% NMP solution and is completely stripped in a 100% phenol solution. Therefore, in order to increase the versatility of the coating resin stripper L so that it can also strip polyvinyl formal, it is considered necessary for the coating resin stripper L to contain the alcohol solvent (E) and to pay attention to its content ratio.
As shown, in the coating resin stripper L Nos. 15 to 20 relating to Test Examples 15 to 20 (the total mass of components (A) to (E) and the organic acid is taken as 100%), the content ratio Z of the alcohol-based solvent (E) was in the range of 20<Z≦35, while in the coating resin stripper L Nos. 22 to 24 relating to Test Examples 22 to 24, Z was >35.
From the above, it has been found that in order to further reliably increase the versatility of the coating resin stripper L for various coating resins, it is essential that the coating resin stripper L contains an alcohol-based solvent (E) and that the content thereof is 20% or more, preferably 23% or more, and does not exceed 35%, relative to 100% total mass of the components (A) to (E) and the organic acid. In other words, when the total mass of the inorganic alkali (A), alkanolamine (B), water (C) and aprotic polar solvent (D) is taken as 100%, the coating resin stripper L of Test Examples 15 to 20 in which the alcohol-based solvent (E) is in the range of 20 to 35%, preferably 22 to 33%, acts as a dissolution stripper for polyamideimide and polyester coating resins and acts as a swelling stripper for polyvinyl formal coating resins, and is a treatment liquid that reliably increases the versatility of the coating resin for various coating resins.

[Test Example C]
In this test example, the coating resin stripping treatment liquid (No. 27 to 35) shown in Table 5 was used, and the test was performed in the same manner as in Test Example A, except that the treatment temperature of the stripping liquid in Examples 27, 28 and 29-2, in which the coating resin was polyester, was 85°C, and the test results are shown in Table 6. The stripping liquids in No. 27 to 29 are three components, alkanolamine (B), water (C) and aprotic polar solvent (D, NMP). The stripping liquids in No. 30 to 35 are four components, inorganic alkali (A), alkanolamine (B), water (C) and aprotic polar solvent (D, DMSO alone or a mixture of NMP and DMSO). None of the treatment liquids used Moresco White. As shown in Table 6, the same polyamideimide resin or polyester resin as in Test Example 1 was used as the material for the coating resin 11.

The coating resin peeling treatment was performed in the same manner as in Test Example A. The treatment temperature was 95° C., the same as in Test Example A, for the stripping solutions No. 30 to 35, but 85° C. for the stripping solutions No. 27 to 29.
The peelability evaluation was carried out in the same manner as in Test Example A. The criteria for the peelability evaluation were the same as those in Test Example A and are shown below.
⊚: "Dissolution and peeling" occurred within 30 minutes of immersion. ◯: "Dissolution and peeling" occurred within 1 hour of immersion. ×: The coating resin could not be removed even after immersion for more than 1 hour.

The stripping solutions No. 27 to 29, which are three-component systems of alkanolamine (B), water (C) and aprotic polar solvent (D, NMP), exhibited excellent stripping properties, similar to the three-component system No. 13, as shown in Table 6. Furthermore, the stripping solutions No. 27 to 29 exhibited excellent stripping properties, even though the treatment temperature was 85° C., which is 10° C. lower than that of Examples A and B.
In addition, the stripping solutions Nos. 30, 32 to 35 (DMSO) and 31 (mixture of NMP and DMSO) which are four-component systems of inorganic alkali (A), alkanolamine (B), water (C) and aprotic polar solvent (D) showed excellent stripping properties, as shown in Table 6, similar to Nos. 4 to 10 and 16 to 20 which used NMP as the polar solvent, and No. 3 which used DMSO as the polar solvent.

[Test Example D]
In this test example, coating resin stripping treatment liquids No. 27 and 28 (heated at 85°C) shown in Table 5 in Test Example C were tested to see whether the treatment liquid after heating could be reused, i.e., whether the weight of the treatment liquid was reduced. In this test, the treatment liquids No. 27 and 28 were heated in a 95°C bath with the cap of the screw bottle removed, and the heat loss in this case was measured. The test results are as follows.
(1) Processing solution No. 27;
(a) Weight of treatment solution after Test Example C: 24.68 g;
Then, after 3 hours at 95°C: 24.20 g (a decrease of 0.12 g, a decrease rate of 1.6%), and after 5 hours at 95°C: 23.77 g (a decrease of 0.83 g, a decrease rate of 3.4%).
(2) Processing solution No. 28;
(a) Weight of treatment solution after Test Example C: 24.82 g;
Then, at 95°C, after 1 hour: 24.81g (decrease of 0.01g, decrease rate: 0.0%), after 3 hours: 24.44g (decrease of 0.38g, decrease rate: 1.5%), after 5 hours: 24.35g (decrease of 0.47g, decrease rate: 1.9%), after 7 hours: 24.02g (decrease of 0.800g, decrease rate: 3.2%).
In the treatment solutions No. 27 and 28, the weight loss rate was only about 1.5% after 3 hours of treatment at 95°C compared to the start. In the treatment solution No. 28, the weight loss rate was almost 0% after 1 hour of treatment at 95°C. Therefore, the weight loss rate of the treatment solutions No. 27 and 28 was extremely small. The actual heating time at 95°C is thought to be about 5 to 30 minutes, and it is thought that excellent releasability can be maintained in practice even if the same treatment solution is used repeatedly. In addition, if the desired releasability is difficult to obtain in the normal time (about 10 minutes to 1 hour) depending on the combination of resin type and metal type, a longer treatment can be performed with peace of mind.

The present invention is not limited to the above-described embodiment and examples, and various modifications or changes are possible. For example, the use method in which the tip of the insulated conductive wire 10 is immersed in the present coating resin remover L to form a contact for passing electricity and the coating resin tip 11a is peeled off has been described, but other use methods may be used. A recycling system for coated electric wires is known (see JP 2014-29817, etc.), and the entire insulated conductive wire 10 can be immersed in the present coating resin remover L to peel off all of the coating resin 11, and can be applied to such a recycling system. Specifically, the entire coating resin 11 is dissolved and peeled off and swollen and peeled off to remove the conductor wire 12 from the insulated conductive wire 10, and the removed conductor wire 12 can be used as a recycled metal material. The above descriptions used in the description of the present invention can be applied to the insulated conductive wire, coating resin remover, coating resin, and peeling conditions used in this recycling system.
The present invention is not limited to the insulated conductive wires, but can also be used in resin-coated metal bodies for other applications, such as automobile parts, home appliance parts, semiconductor parts, electrical and electronic parts, and daily necessities.

The present invention is used in fields such as coating resin removal and stripping, where the coating resin is dissolved or stripped from an insulated conductive wire, exposing or reusing a conductor wire from an insulated conductive wire, treating waste such as used insulated conductor wire, and recovering useful conductor wire metal.

10: Insulated conductive wire 101: Single insulated conductive wire 101a: Magnet wire 102: Assembly type insulated conductive wire 11: Coating resin 11a: Coating resin tip 11b: Edge portion 12: Conductor wire 12a: Conductor wire tip L: Coating resin stripping liquid _L0 : Coating resin stripping treatment liquid _L1 : Stripping treatment layer _L2 : Evaporation prevention layer

Claims (16)

A coating resin remover for removing a coating resin from an insulated conductive wire having a conductor wire and a coating resin coating the conductor wire, comprising:
An inorganic alkali (A);
The solvent comprises an alkanolamine (B) having 1 to 10 carbon atoms, water (C), and an aprotic polar solvent (D) having a boiling point of 100° C. or higher and having 2 to 6 carbon atoms,
The inorganic alkali (A) is contained in the coating resin stripping solution in an amount of 0.4% by mass or more and 4% by mass or less,
The coating resin stripping solution comprises the alkanolamine (B) in an amount of 15% by mass or more and 60% by mass or less. The coating resin stripper according to claim 1, wherein the inorganic alkali (A) is contained in the coating resin stripper in an amount of 0.4% by mass or more and 3% by mass or less. In the coating resin stripping solution, the inorganic alkali (A) is 0.4% by mass or more and 3% by mass or less,
The alkanolamine (B) is 15% by mass or more and 60% by mass or less,
The water (C) is 2% by mass or more and 40% by mass or less,
The coating resin stripping solution according to claim 2 , wherein the aprotic polar solvent (D) is contained in an amount of 20% by mass or more and 80% by mass or less. The coating resin stripper according to any one of claims 1 to 3 further contains at least one alcohol-based solvent (E) having a boiling point of 100°C or higher, selected from linear or branched alcohols having 2 to 6 carbon atoms and monovalent to trivalent alcohols, and aromatic alcohols having 2 to 8 carbon atoms and monovalent to trivalent alcohols. The coating resin stripper according to claim 4, wherein the alcohol-based solvent (E) is 20% by mass or more and 50% by mass or less when the total of the components (A), (B), (C) and (D) is 100% by mass. The coating resin stripper according to claim 5, wherein the coating resin is one or more selected from the group consisting of polyacetal resin, polyester resin, polyurethane resin, polyamide resin, polycarbonate, polyimide resin, polyesterimide resin, polyamideimide resin, and polyesteramideimide resin. A coating resin remover for removing a coating resin from an insulated conductive wire having a conductor wire and a coating resin coating the conductor wire, comprising:
The solvent comprises an alkanolamine (B) having 1 to 10 carbon atoms, water (C), and an aprotic polar solvent (D) having a boiling point of 100° C. or higher and having 2 to 6 carbon atoms,
The alkanolamine (B) is contained in an amount of 15% by mass or more and 70% by mass or less, the water (C) is contained in an amount of 4% by mass or more and 18% by mass or less, and the aprotic polar solvent (D) is contained in an amount of 20% by mass or more and 80% by mass or less,
The coating resin is at least one selected from the group consisting of polyester resins, polyurethane resins, polyamide resins, polycarbonate resins, polyimide resins, polyesterimide resins, polyamideimide resins, and polyesteramideimide resins. A release treatment layer comprising the coating resin stripping solution according to any one of claims 1 to 7;
A coating resin stripping treatment liquid comprising: an oily component including a higher aliphatic hydrocarbon; and an evaporation prevention layer disposed on the release treatment layer separately from the release treatment layer. The coating resin peeling treatment liquid according to claim 8 , wherein the evaporation prevention layer comprises 0.5% by mass or more and 10% by mass or less, when the total amount of the components of the peeling treatment layer is taken as 100% by mass. A coating resin stripping method using the coating resin stripping treatment liquid according to claim 8 or 9, comprising the coating resin stripping liquid according to claim 1,
the conductor wire is made of copper, a copper alloy, aluminum, or an aluminum alloy;
the coating resin is at least one selected from the group consisting of polyester-based resins, polyurethane-based resins, polyamide-based resins, polycarbonates, polyimide-based resins, polyesterimide resins, polyesterimide resins, polyamideimide resins, and polyesteramideimide resins;
Immerse the insulated conductive wire in the coating resin stripper at a temperature of 75° C. or higher and 120° C. or lower to expose the conductor wire;
A coating resin stripping method, characterized in that one type of coating resin stripping solution is used even when the materials of the conductor wires are different and even when the types of the coating resins are different. A coating resin stripping method using the coating resin stripping treatment liquid according to any one of claims 4 to 6 or the coating resin stripping treatment liquid according to claim 8 or 9, comprising the coating resin stripping liquid according to any one of claims 4 to 6,
the conductor wire is made of copper, a copper alloy, aluminum, or an aluminum alloy;
the coating resin is at least one selected from the group consisting of polyacetal resins, polyester resins, polyurethane resins, polyamide resins, polycarbonates, polyimide resins, polyesterimide resins, polyesterimide resins, polyamideimide resins, and polyesteramideimide resins;
Immerse the insulated conductive wire in the coating resin stripper at a temperature of 75° C. or higher and 120° C. or lower to expose the conductor wire;
A coating resin stripping method, characterized in that one type of coating resin stripping solution is used even when the materials of the conductor wires are different and even when the types of the coating resins are different. A coating resin stripping method using the coating resin stripping solution according to claim 7 or the coating resin stripping treatment solution according to claim 8 or 9, which comprises the coating resin stripping solution according to claim 7,
The material of the conductor wire is copper or a copper alloy,
the coating resin is at least one selected from the group consisting of polyester-based resins, polyurethane-based resins, polyamide-based resins, polycarbonates, polyimide-based resins, polyesterimide resins, polyesterimide resins, polyamideimide resins, and polyesteramideimide resins;
Immerse the insulated conductive wire in the coating resin stripper at a temperature of 75° C. or higher and 120° C. or lower to expose the conductor wire;
A coating resin stripping method, characterized in that one type of coating resin stripping solution is used even when the materials of the conductor wires are different and even when the types of the coating resins are different. A coating resin stripping method characterized in that after carrying out the first coating resin stripping method described in any one of claims 10 to 12, the coating resin stripping solution remaining after the first treatment, or after a further treatment if any, is continuously used. A coating resin stripping method using the coating resin stripping treatment liquid according to any one of claims 4 to 6 or the coating resin stripping treatment liquid according to claim 8 or 9, comprising the coating resin stripping liquid according to any one of claims 4 to 6,
the conductor wire is made of copper, a copper alloy, aluminum, or an aluminum alloy;
the coating resin is at least one selected from the group consisting of polyester-based resins, polyurethane-based resins, polyamide-based resins, polycarbonates, polyimide-based resins, polyesterimide resins, polyesterimide resins, polyamideimide resins, and polyesteramideimide resins;
Immerse the insulated conductive wire in the coating resin stripper at a temperature of 75° C. or higher and 120° C. or lower to expose the conductor wire;
This coating resin stripping method is characterized in that even when the materials of the conductor wires are different and even when the types of the coating resins are different, one type of coating resin stripping solution can be used, and since the coating resin is dissolved and stripped, there is no need to recover the stripped resin, and the remaining coating resin stripping solution can be continuously used after the treatment. 13. The coating resin stripping method according to claim 10, further comprising the steps of: immersing the insulated conductive wire in the coating resin stripping treatment liquid to expose the conductor wire; recovering the exposed conductor wire; and reusing the exposed conductor wire. The coating resin peeling treatment method according to claim 13 or 14,
The temperature of the coating resin stripping solution is 75° C. or more and 95° C. or less, and the exposed conductor wire is recovered to reuse the exposed conductor wire;
Furthermore, after the first coating resin stripping treatment method is carried out at 75° C. or more and 95° C. or less, the coating resin stripping solution remaining after the first treatment or after any further treatment, if any, is continuously reused;
A coating resin stripping method, characterized in that when the coating resin stripping solution after the first use is heated at 95° C. for 3 hours, the loss on heating is 1.6% or less compared to before heating.

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