JPS6315690B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of manufacturing an insulated wire without using a solvent, and particularly to a method of manufacturing an insulated wire that is insulated and coated with a polyester resin and has various characteristics comparable to conventional magnet wires. Conventionally, when manufacturing insulated wires used as magnet wires for motors, etc., it is common to apply an insulating paint obtained by dissolving resin in an organic solvent onto a conductor and dry and solidify it. At this time, a large amount of solvent is used to adjust the viscosity of the paint in order to make it easier to coat the conductor with the paint, but due to the toxicity of the solvent used and incomplete recovery of the solvent, it is difficult to improve the working environment. Also, from the viewpoint of resource saving, there is a strong desire for a method of manufacturing insulated wires that does not use solvents. In response to this demand, a method has been proposed in which a resin having high strength and low melt viscosity, such as linear polyester, is melt-coated onto a conductor by extrusion molding (Japanese Patent Application Laid-Open No. 4875/1983). However, since the insulated wire obtained by this method is simply a conductor coated with thermoplastic resin, it has poor mechanical strength including abrasion resistance.
Due to its poor heat deterioration resistance, it is impossible to obtain an insulated wire that passes JIS standards and can be used as a magnet wire, and even if it can be used, it can only be used in extremely limited equipment. do not have. In other words, since resins such as linear polyester are crystalline polymers, if they are stretched or bent during coil processing, microscopic cracks will occur, resulting in a decrease in electrical properties, as well as deterioration due to drying, etc. Loss of flexibility due to crystallization is also observed when heated. As a test method for heat deterioration resistance of magnet wire, a test is specified in JIS C3203, 3210, 3211, etc., in which the flexibility is observed after heating for a specified time (for example, for polyester enal copper wire, heating at 200℃ for 6 hours) Even in the later winding property), the flexibility completely disappears due to crystallization. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing an insulated wire without using a solvent, which does not have the above-mentioned drawbacks, and has sufficient performance to be used as a magnet wire. In order to achieve the above-mentioned object, the present inventors have conducted extensive research into a method for manufacturing insulated wires that does not use solvents, and as a result, they have first covered a linear conductor with a substantially linear polyester resin, and then By heating this resin coating layer to a temperature higher than the melting point of the resin, it was possible to obtain the characteristics of an insulated wire, but compared to an insulated wire manufactured using a solvent-based paint, the heat softening characteristics, etc. It was still inferior in terms of heat resistance. As a result of further investigation, we found that by coating a polyester resin with a stable polyfunctional unsaturated monomer and crosslinking it by heating, the crosslinking density of the coating layer increases and the heat resistance improves. The present invention was achieved based on the discovery that the bonding strength of the crosslinks is strengthened and the thermal stability can also be improved, thus eliminating the above-mentioned drawbacks. The present invention is directed to (a) a substantive substance whose main component is an ester bond consisting of an acid component mainly consisting of a dicarboxylic acid in which an aromatic group or a part thereof is replaced with an aliphatic group, and a diol component mainly consisting of an aliphatic diol. The linear polyester resin (A) has two or more aliphatic unsaturated groups having at least one hydrogen atom at the carbon atom α-position with respect to the double bond in the molecule, and the polyester A compound (B) that is substantially stable with respect to the polyester resin (A) under melt blending conditions with the polyester resin (A) is added to the polyester resin (A) 100%.
A linear conductor is coated with a polyester composition containing 1 to 30 parts by weight, and (b) this coating layer is heated to a temperature equal to or higher than the melting point of the polyester resin (A) in an oxygen-containing atmosphere. The gel fraction of the coating layer is
The above objective is achieved by crosslinking to 20% or more. The acid component constituting the linear polyester resin (A) used in the present invention is an aromatic acid or a dicarboxylic acid in which a portion thereof is replaced with an aliphatic acid. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl sulfone dicarboxylic acid,
Examples include diphenoxyethane dicarboxylic acid, diphenyl ether dicarboxylic acid, methyl terephthalic acid, methyl isophthalic acid, and terephthalic acid is particularly preferred. In addition, aromatic dicarboxylic acid is 30 mol% of that amount.
Hereinafter, aliphatic dicarboxylic acids such as succinic acid, adipic acid, and sebacic acid can be contained preferably in a proportion of 20 mol% or less. Further, examples of the aliphatic diol component constituting the linear polyester resin (A) include ethylene glycol, trimethylene glycol, tetramethylene glycol, hexanediol, and decanediol. Particularly preferred are ethylene glycol and tetramethylene glycol. Further, part of the aliphatic diol can be oxy(alkylene) glycol, for example, polyethylene glycol or polytetramethylene glycol. The polyfunctional unsaturated monomer used in the present invention has two or more aliphatic unsaturated groups having at least one hydrogen atom at the carbon atom α-position with respect to the double bond in the molecule. Moreover, the compound (B) is substantially stable with respect to the polyester resin (A) under melt blending conditions with the polyester resin (A). Here, "a compound that is substantially stable under melt-blending conditions with the polyester resin (A)" refers to a compound that is substantially stable under melt-blending conditions with the polyester resin (A), for example, at a temperature of the melting point of the polyester resin (A) + 20°C. When kept in an inert gas atmosphere for 15 minutes, for example, the aliphatic unsaturated groups do not react with each other or with the polyester resin (A), and the aliphatic unsaturated groups are stabilized. means that it exists in Such an unsaturated group is preferably a non-conjugated aliphatic unsaturated group, particularly the following general formula (): A non-conjugated group having at least two hydrogen atoms at the carbon α-position with respect to the double bond represented by, for example, an allyl group, a substituted allyl group, etc. is preferable. In the group represented by the above general formula (), the bonds (a), (b), (c) and (d) are bonded to a hydrogen atom or an organic group, and the bond (e) is bonded to a bonding group. There is.
The organic groups bonded to the bonds in (a), (b), (c), (d), and (e) may be independent, or may be bonded to each other to form a ring structure. . When forming a ring structure, the double bond in formula () can also form a part of the ring structure. At this time, this ring structure is an alicyclic ring,
Although it may have a ring structure such as a heterocycle, it does not form an aromatic ring. A more preferable structure for the group represented by the above general formula () is represented by the following general formula (). [However, in the formula, R ₁ , R ₂ and R ₃ are the same or different and each represents a member selected from the group consisting of a hydrogen atom and an organic group. ] In the general formula (), preferred examples of organic groups for R ₁ , R ₂ and R ₃ include C ₁ to _{C 6} alkyl, more preferably C ₁ to C ₃ alkyl. Among the groups represented by formula (), ie, allyl and substituted allyl, allyl, metaallyl and crotyl groups are preferred, and allyl group is particularly preferred. Compounds having at least two such unsaturated groups
When (B) is blended into a polyester resin, not only is the aliphatic unsaturated group in the compound (B) stable under melt blending conditions with the polyester, but also the compound (B) itself is stable. It needs to be stable, so when compound (B) is melt-blended, the resulting polyester composition is 35%
It is necessary that there is substantially no insoluble material that does not dissolve at 0.degree. C., and that the [η] of the polyester does not decrease significantly. Therefore, compounds that contain highly reactive ester-forming functional groups (for example, highly reactive esters, highly reactive hydroxyl groups, highly reactive carboxyl groups, etc.), and furthermore, may decompose at the melting temperature of polyester resin. Compounds that are oxidized or gasified are not preferred as compounds for use in the present invention. A compound having a group represented by the above general formula ()
A specific example of (B) is given below. () Compounds having an amide bond and/or an imide bond: (1) A compound represented by the following formula () Q ₁ {X(Q ₁ A) _n ″} _o ″ ………() However, in the formula () , A is: a monovalent group having the structure represented by the above formula (), preferably an allyl group or a substituted allyl group represented by the above (); X is: -CONR ₁₁ - (where R ₁₁ is a hydrogen atom or _C1 - _C5 alkyl group),

【formula】

[Formula] (wherein R ₁₁ is as described above, and two R _11s may be the same or different) and -O-. Q ₁ is: mono- to tetravalent aliphatic value of C ₂ to C ₂₀ , C ₄ to
C ₁₂ mono- to tetravalent aliphatic group,

[Formula] (where R ₁₂ is a hydrogen atom, C ₆ to C ₁₂ aryl group, C ₁
~ _C6 alkyl group, _C1 - _C6 alkyloxy group,
1-4 consisting of nitro group or halogen atom)
the basis of valence,

A mono- to tetravalent group consisting of [Formula] (where R ₅ is as above) and

[Formula] [Here, Y is -O-, -CO-, -SO ₂ -, -NR ₁₁
− (However, R ₁₁ is the same as above), −O(CH ₂ CH ₂ ) _l ′O−
(where l' is an integer of 1 to 3), a member selected from the group consisting of C ₂ to C ₁₂ alkylene]
A group selected from the group consisting of tetravalent groups, and when X in the above is -O-, Q ₁ is preferably the above aliphatic group or alicyclic group. The aliphatic group mentioned above is a C ₂ to C ₂₀ alkylene group,
2~ having the structure represented by the above general formula ()
4 olefin residues,

【formula】 etc. are preferable, and the aliphatic group is

【formula】 A mono- to tetravalent group consisting of,

1~ consisting of [formula] tetravalent group,

Preferred examples include divalent to tetravalent groups consisting of the formula: Q′ ₁ is: a direct bond or a divalent or higher group in Q ₁ , preferably a direct bond or C ₁ to _{C 5}
is an alkylene group. m″ and n″ are each an integer from 1 to 4,
It is preferable that m″×n″≧2. Examples of such compounds of formula () are:
The following compounds can be exemplified. N,N'-diallyl (or dimethallyl or dicrotyl) adipamide, N,N'-diallyl (or dimethallyl or dicrotyl) sebecamide, N,N'-diallyl (or dimethallyl or dicrotyl) decanedicarboxamide, N,N'- Diallyl (or dimethallyl or dicrotyl) terephthalamide, N,N'-diallyl (or dimethallyl or dicrotyl) isophthalamide, N,
N'-diallyl (or dimethallyl or dicrotyl) naphthalene dicarboxamide,
N,N'-diallyl (or dimethallyl or dicrotyl) hexahydroterephthalamide,
(or Tetramethallyl (or tetracrotyl) adipamide, N,N,N',N''-Tetralyl (or tetramethallyl or tetracrotyl) sebavacamide, N,N,N',N''-
tetraallyl (or tetramethallyl or tetracrotyl) decanedicarboxamide,
N,N,N',N''-tetraallyl (or tetramethallyl or tetracrotyl) terephthalamide, N,N,N',N''-tetraallyl (or tetramethallyl or tetracrotyl)
Isophthalamide, N,N,N′,N″-tetraallyl (or tetramethallyl or tetracrotyl) naphthalene dicarboxamide, N,
N-diallyl (or dimethallyl or dicrotyl)benzamide, N,N,N',N'-tetraallyl (or tetramethallyl or tetrachlor) hexahydroterephthalamide,
N,N,N',N'-tetraallyl (or tetramethallyl or tetracrotyl)diphenoxyethanedicarboxamide, N,N,N',
N', N'', N''-hexaallyl (or hexametaallyl or hexacrotyl) trimesic acid amide, N, N, N', N', N'', N''-hexaallyl (or hexametaallyl or hexacrotyl) trimellitic acid amide , N, N, N′,
N′, N″, N″, N, N′′′′-octaallyl (or octamethallyl or octacrotyl)
Pyromellitic acid amide, N,N'-diallyl (or dimethallyl or dicrotyl) pyromellitimide, N,N'-diallyl (or dimethallyl or dicrotyl)benthophenone-3,4,3',4'-tetracarboxylic acid bisimide, N , N'-diallyl (or dimethallyl or dicrotyl)butane-1,2,3,4
-tetracarboxylic acid bisimide, N,N'-diallyl (or dimethallyl or dicrotyl)cyclopentane-1,2,3,4-tetracarboxylic acid bisimide, ethylenebis[N-allyl (or N-methallyl or N-crotyl) trimellitic acid imide]amide, tetramethylenebis[N-allyl (or N-methallyl or N-crotyl) trimellitic acid imide]amide, hexamethylenebis[N-allyl (or N-methallyl or N-crotyl)
Trimellitic acid imide] amide, decamethylene bis [N-allyl (or N-methallyl or N-crotyl) trimellitic acid imide] amide, dodecamethylene bis [N-allyl (or N-methallyl or N-crotyl) trimellitic acid imide] Amide, (However, A: allyl or metaallyl or crotyl), N,N'-diallyl (or dimethallyl or dichloro) trimellitic acid amide imide, N,N,N'-triallyl (or trimethallyl or tricrotyl) trimellitic acid amide imide, ethylene (or trimethylene or tetramethylene or hexamethylene or decamethylene) bis(2-propylenecarboxamide), ethylene (or trimethylene or tetramethylene or hexamethylene or decamethylene) bis[2-(or 3-)
butenecarboxamide], ethylene (or trimethylene or tetramethylene or hexamethylene or decamethylene) bis[2-
(or 3- or 4-) pentenecarboxamide], ethylene (or trimethylene or tetramethylene or hexamethylene or decamethylene) bis[2- (or 3- or 4- or 5-) hexenecarboxamide],
N-allyl (or crotyl or metaallyl) 2-propylenecarboxamide, N-allyl (or crotyl or metaallyl) 2-
(or 3-)butenecarboxamide, N-
Allyl (or crotyl or metaallyl)2
-(or 3-or 4-)propenecarboxamide, N-allyl (or crotyl or metaallyl) 2-(or 3-or 4-or 5-)hexenecarboxamide, N,N-
Diallyl (or dicrotyl or dimethallyl) 2-propylenecarboxamide, N,N
- diallyl (or dicrotyl or dimethallyl) 2-(or 3-)butenecarboxamide, N,N-diallyl (or dicrotyl or dimethallyl) 2-(or 3- or 4)
-) propenecarboxamide, N,N-diallyl (or dicrotyl or dimethallyl)
2-(or 3-or 4-or 5-)hexenecarboxamide, N,N'-diallyl (or dicrotyl or dimethallyl) 3-
(or 2) hexene 1,6-dicarboxamide N,N'-diallyl (or dicrotyl or dimethallyl) 2-butene 1,4-dicarboxamide, N,N,N',N'-tetraallyl (or tetracrotyl or Tetramethallyl) 3-(or 2)hexene 1,6-dicarboxamide, N,N,N',N'-tetraallyl (or tetracrotyl or tetramethallyl) 2-butene 1,4-dicarboxamide, ethylene (or trimethylene or tetramethylene or hexamethylene or decamethylene) bis 2- (or 3-) cyclohexenecarboxamide, ethylene (or trimethylene or tetramethylene or hexamethylene or decamethylene) bis 3- (or 4
-) Cyclohexene 1,2-dicarboximide, ethylene (or trimethylene or tetramethylene or hexamethylene or decamethylene) bis-2- (or 3-) cyclohexene 1,1-dicarboximide, ethylene (or trimethylene or tetramethylene or hexamethylene or decamethylene) methylene or decamethylene) bis2-
cyclohexene 1,4-dicarboximide,
N-allyl (or crotyl or metaallyl) 2-(or 3-)cyclohexenecarboxamide, N-allyl (or crotyl or metaallyl) 3-(or 4-)cyclohexene 1,2-dicarboximide, N-allyl (or crotyl or metaallyl) 2-(or 3-)cyclohexene 1,1-dicarboximide, N-allyl (or crotyl or metaallyl) 2-cyclohexene 1,4-dicarboximide, N-allyl (or crotyl or metaallyl) bicyclo [2,2,1]-3
-hebutene 2,3-dicarboximide, N,
N-diallyl (or dicrotyl or dimethallyl) 2-(or 3-)cyclohexenecarboxamide, N,N,N',N'-tetraallyl (or tetracrotyl or tetramethallyl) 3-(or 4-)cyclohexene 1,
2-dicarboxamide, N,N,N',N'-
Tetraallyl (or tetracrotyl or tetramethallyl) 2-(or 3-)cyclohexene 1,1-dicarboxamide, N,N,
N',N'-tetraallyl (or tetracrotyl or tetramethallyl) 2-cyclohexene 1,4-dicarrboxamide, N,N,
N′,N′-tetraallyl (or tetracrotyl or tetramethallyl) bisitalo [2,
2,1]-5-heptene 2,3-dicarboxamide, N,N'-diallyl (or dicrotyl or dimethallyl) 2-cyclohexene 1,4-dicarboxamide. () Derivatives of cyanuric acid or isocyanuric acid; Compounds represented by the following formula () or () However, in expressions () and (), multiple
A' may be the same or different, and at least two of them are the group A, and the rest are the group A or the monovalent group in _Q1 . Q ₂ is a divalent to tetravalent group in Q ₁ above. Q′ ₂ is a divalent group in Q ₁ above. and r is 0 or 1, preferably 1, p is an integer of 0 to 10, and q is an integer of 1 to 3. Examples of the compounds represented by the formulas () and () include the following compounds. triallyl (or tricrotyl or trimetaallyl) isocyanurate, diallyl (or dicrotyl or dimethallyl) methyl isocyanurate, diallyl (or dicrotyl or dimethallyl) ethyl isocyanurate, diallyl (or dicrotyl or dimethallyl) decyl isocyanurate, diallyl (or dicrotyl or dimethallyl) Dodecyl isocyanurate, diallyl (or dicrotyl or dimethallyl) silistyl isocyanurate, diallyl (or dicrotyl or dimethallyl) cetyl isocyanurate, diallyl (or dicrotyl or dimethallyl) stearyl isocyanurate, ethylene bis[diallyl (or dicrotyl or dimethallyl) isocyanurate ], tetramethylenebis[diallyl (or dicrotyl or dimethallyl) isocyanurate], hexamethylenebis[diallyl (or dicrotyl or dimethallyl) isocyanurate], decamethylenebis[diallyl (or dicrotyl or dimethallyl) isocyanurate] oxydiethylenebis[ Diallyl (or dicrotyl or dimethallyl) isocyanurate] dioxytoluethylenebis[diallyl (or dicrotyl or dimethallyl) isocyanurate], polyethylene allyl (or metaallyl or crotyl) isocyanurate, terminally terminated with diallyl isocyanurate residues, Polytetramethylene allyl (or meta-allyl or crotyl) isocyanurate which is an isocyanurate residue, polyhexamethylene allyl (or meta-allyl or crotyl) isocyanurate whose terminal is a diallyl isocyanurate residue, whose terminal is a diallyl isocyanurate residue Polydecamethylene allyl (or metaallyl or crotyl) isocyanurate, triallyl (or trimetaallyl or tricrotyl) cyanurate, diallyl (or dimethallyl or dicrotyl) methyl cyanurate,
Diallyl (or dimethallyl or dicrotyl) ethyl cyanurate, diallyl (or dimethallyl or dicrotyl) decyl cyanurate, diallyl (or dimethallyl or dicrotyl) dodecyl cyanurate, diallyl (or dimethallyl or dicrotyl) myristyl cyanurate, diallyl (or dimethallyl or dicrotyl) ) cetyl cyanurate, diallyl (or dimethallyl or dicrotyl) stearyl cyanurate, tetramethylenebis[diallyl (or dimethallyl or dicrotyl) cyanurate], hexamethylenebis[diallyl (or dimethallyl or dicrotyl) cyanurate], decamethylenebis[diallyl ( polytetramethylene allyl (or Metaallyl or crotyl) cyanurate, polyhexamethylene allyl (or metaallyl or crotyl) cyanurate, which terminates in a diallyl cyanurate residue, polydecamethylene allyl (or metaallyl or crotyl) cyanurate, which terminates in a diallyl cyanurate residue. These compounds include, for example, Zh, Organ,
Khim., 2(10), p1742-3 (1965) (Russ), or J. Am. Ohem. Soc., 73 p3003 (1951)
It can be easily synthesized by the method shown in . () A polymer obtained from a compound having a reactive functional group, such as a compound represented by the above general formula (); (1) A polyester represented by the following formula () or () [However, in the formula, A and Q' ₂ have the same definitions as above, and Q ₃ is

A 3-(k+2)-valent group consisting of [Formula] (where R ₁₂ is the same as the above definition),

A trivalent to (k+2) valent group consisting of [Formula] (where R ₁₂ is the same as defined above) or

A 3-(k+ 2)-valent group consisting of [Formula], where k is an integer of 1-4, s is 0 or 1, t is an integer greater than 2, and k×t≧2
It is. ] It is a polymer having the repeating unit. In such a polymer, the polymer () is s
= 1, Q′ ₂ (COOH) ₂ or its ester-forming derivative (e.g. C ₁ -C ₃ alkyl ester,
_C6 - _C12 aryl esters, acid halides)
and, when s=0, a compound such as COCl ₂ , OOBr ₂ , diaryl carbonate, etc.

[Formula] or its ester-forming derivatives (for example, lower fatty acid esters, alkali metal salts, etc.) can be obtained by reacting with a conventionally known method, and the compound of () is when s=1,

[Formula] or its ester-forming derivative, and when s=0,

It can be obtained by reacting [Formula] or its ester-forming derivative by a conventionally known method. In the present invention, the terminal ends of these polymers become the terminal ends of the components forming the compound represented by the above formula, but it is preferred to convert them into terminals in the form of, for example, alkyl- or aryl-esters, by conventional methods. Examples of such polymers of formulas () and () include polymers having the following repeating units (provided that A in the following compounds is allyl, metaallyl, or crotyl). These are relatively unreactive compounds. (2) Polyamide Poly(ethylene-2-butene 1,4-dicarboxamide), poly(tetramethylene-
2-butene 1,4-dicarboxamide),
poly(hexamethylene-2-butene 1,4-
dicarboxamide), poly(decamethylene-2-butene 1,4-dicarboxamide),
Poly(ethylene 3-(or 2-)hexene 1,6-dicarboxamide), poly(tetramethylene 3-(or 2-)hexene 1,
6-dicarboxamide), poly(hexamethylene 3-(or 2-)hexene 1,6-
dicarboxamide), poly(decamethylene 3-(or 2-)hexene 1,6-dicarboxamide) Among the compounds (), (), and () above, the compound () or () is more preferable;
The compounds in parentheses () are most preferred. moreover()
Among these compounds, it is preferable that there are four or more allyl or substituted allyl groups in the molecule. The reason for this is that it is structurally heat resistant, has high reactivity, and can be used safely from the standpoint of self-crosslinking, and when such a compound is used, an excellent insulated wire can be obtained. The polyester composition used in the present invention contains 1 to 30 parts by weight per 100 parts by weight of the polyester resin (A),
Preferably, in a composition containing 5 to 20 parts by weight of the above compound (B), if the amount of component B is less than 1 part by weight, the effect of adding component B will not be sufficiently exhibited;
Even if more than % by weight is added, the effect of adding component B will not increase. The polyester composition can be obtained by mixing component A and component B by any method. In addition, various additives such as UV absorbers, stabilizers such as antioxidants, pigments, and fillers such as glass fibers can be added to the polyester composition used in the present invention as required. . Coating with the polyester composition can be easily carried out by applying the polyester composition in a heated molten state, or by a conventional molding method for thermoplastic resins such as extrusion molding, injection molding, etc. The polyester composition layer covering the linear conductor must be heated in an oxygen-containing atmosphere. The reason for this is that when heated in an oxygen-free atmosphere, the degree of crosslinking is extremely low, and it is difficult to crosslink until the gel fraction of the coating layer reaches 20% or more. Air, which is industrially easiest to use, can be used as the oxygen-containing atmosphere. Therefore, the conventional baking furnace for enamelled electric wires that uses a solvent can be used as is, and no new equipment is required, which is advantageous. The heating temperature must be higher than the melting point of the polyester resin (A) used; if it is lower than the melting point, crystallization may proceed, resulting in loss of flexibility and the film forming during folding, winding, etc. may fall off. The polyester composition coating layer is crosslinked by heating until its gel fraction becomes 20% or more. Here, "gel fraction" means 90% using m-cresol.
It is the ratio of the insoluble residue to the total coating layer when heated at °C. When the gel fraction is less than 20%, it is difficult to obtain the characteristics necessary for an insulated wire for a magnet wire. The mechanism by which the resin coating layer crosslinks due to heating is not clear, but heating in an oxygen-containing atmosphere causes scission and oxidation of the main chain due to the action of oxygen and heat, resulting in the generation of free radicals and the crosslinking of molecules. It is assumed that this occurs, resulting in insolubility.
Component B, which is a polyfunctional unsaturated monomer, reacts not only with each other but also with free radicals generated during the course of thermal crosslinking of the polyester resin (A). It is believed that when component B coexists, a stronger crosslinked product is produced than when component A is used alone, and therefore superior heat resistance can be obtained than when only thermal crosslinking is used. Comparing the heat resistance of insulated wires for magnet wires with respect to the increased heat softening temperature, which is an important characteristic, those with only thermal crosslinking are
The temperature is about 280°C, whereas that obtained by blending component B and thermally crosslinking shows an improvement of about 300 to 310°C. In manufacturing an insulated wire according to the present invention,
The steps of coating and heating the polyester composition must be carried out continuously using a running linear conductor. The coating layer is heated to a temperature higher than the melting point of the resin (A) in the heating process and melts, becoming liquid like when applying conventional paints that use solvents. Otherwise, the coating layer may become uneven or fall off. Furthermore, if only a wire conductor is fused and coated with polyester resin, bending stress is applied when winding the resulting wire onto a bobbin, etc., which may cause crystallization and cracks. It is necessary to carry out the method of the present invention continuously using a running linear conductor. The insulated wire produced by the method of the present invention has a rising heat softening rate, which is a measure of its heat resistance, equivalent to that of an insulated wire produced using a solvent-based paint. In addition, traditional manufacturing methods that use solvents
In the coating and baking process for film formation, the amount of coating applied to the linear body at one time is limited in order to release the solvent and reaction products.For example, when using a conductor with a diameter of 1.0 mm, the coating and baking process is limited. at least 3
It is also an advantage of the invention that a single coating and heating operation is sufficient for the method of the invention, as opposed to having to be repeated several times. Furthermore, in the method of the present invention, the line speed can be significantly higher than in the case of thermal crosslinking alone without blending component B, so there is a great economic advantage in terms of manufacturing costs. Next, the present invention will be explained with reference to examples. Example 1 Polyethylene terephthalate resin (manufactured by Teijin Ltd.,
20 parts by weight of triallylisocyanurate (manufactured by Nippon Kasei Co., Ltd.) was blended per 100 parts by weight (trade name TR-4550BH, melting point 250-260°C), melt-blended at 270°C, and placed in a tank in the molten state. Ta. A copper wire with a diameter of 0.85 mm was passed through this tank, and a die was squeezed at the exit to form a coating film with a thickness of 28 to 31 μm. This coated wire was then passed through an air atmosphere furnace with a furnace length of 6 m and a furnace temperature of 400° C. at a line speed of 9 m/min to obtain an insulated wire. When the rising heat softening temperature of this insulated wire was measured, it was 310°C. A resin film was removed from this insulated wire and its gel fraction was measured and found to be 95%. Measurement of rising heat softening temperature is JIS C
The test was conducted according to the test method 13.1.1.Crossover method (2) Temperature raising method specified in -3003 (the load was 800g). That is, take two test pieces approximately 10 cm long from the same roll, stack them at right angles, place them on a flat plate, place an 800 g weight on the overlapped part, place this in a thermostatic oven, and place the test pieces on a flat plate. 50 or 60Hz between conductors
An AC voltage of 100 V with a waveform similar to a sine wave was applied, the temperature was raised at a rate of about 2°C/minute, and the temperature at which a short circuit occurred was measured. Comparative Example 1 An insulated wire was obtained in the same manner as in Example 1, except that triallylisocyanurate was not blended and the line speed was changed to 4 m/min. The elevated heat softening temperature and gel fraction of this insulated wire were measured in the same manner as in Example 1. The rising heat softening temperature is 280℃ and the gel fraction is
It was 92%. Comparative Example 2 The same polyethylene terephthalate resin as in Example 1 was melted at 270°C and placed in a tank in the molten state. A copper wire with a diameter of 0.85 mm was passed through this tank, and a die was squeezed at the outlet to form a coating film with a thickness of 28 to 31 μm.The coated wire was then immediately cooled with water to obtain an insulated wire. The elevated heat softening temperature and gel fraction of this insulated wire were measured in the same manner as in Example 1. The rising heat softening temperature was 250°C and the gel fraction was 0%. Example 2 N, N, instead of triallylisocyanurate
An insulated wire was obtained under the same conditions as in Example 1 except that N',N'-tetraallyl terephthalamide was used. The increased thermal softening temperature and gel fraction of this insulated wire were measured in the same manner as in Example 1. The heat softening temperature was 300°C and the gel fraction was 93%. Examples 1 and 2 and Comparative Examples 1 and 2
The various properties of the insulated wire obtained were measured according to JIS3210. The measurement results are shown in Table 1.

[Table] From the measurement results of elevated heat softening temperature, gel fraction, and wire characteristics shown in Examples 1 and 2 and Comparative Examples 1 and 2, the following can be found. Regarding the increased heat softening temperature, insulated wires manufactured using conventional solvent-type paints have a softening temperature of 300°C, whereas those containing triallylisocyanurate shown in Example 1 of the present invention have a softening temperature of approximately 310°C. Although the values are similar, those of Comparative Example 1 without triallylisocyanurate have a lower temperature of 280°C than the conventional solvent type, indicating that there is a problem.
In addition, the one shown in Comparative Example 2 without thermal crosslinking was 250
It can be seen that the temperature is even lower than that of the insulated wire for magnet wires. Regarding the gel fraction, Example 1 in which triallylisocyanurate was blended and Comparative Example 1 in which triallylisocyanurate was not blended had almost the same value, but the gel fraction in Example 1 blended with triallylisocyanurate was It is thought that the increased thermal softening temperature is higher because it has a three-dimensional structure that is stronger than that of a single thermally crosslinked structure. In addition, the line speed was 4 m/min for the line without triallyl isocyanurate (Comparative Example 1), whereas the line speed for the line with triallyl isocyanurate mixed (Example 1) was 9 m/min.
It can be seen that the speed has improved to m/min. Also, instead of triallyl isocyanurate, N,
Example 2, which used N,N',N'-tetraallyl terephthalamide, showed values similar to those of Example 1, which used triallyl isocyanurate, in terms of increased heat softening temperature and gel fraction. The characteristics are
Although it meets the JIS standard, it shows a slightly lower value.
This seems to be due to the difference in crosslinked structure. Example 3 and Comparative Examples 3, 4 and 5 The same polyethylene terephthalate as in Example 1 was used, but the same triallyl isocyanurate as in Example 1 was not blended as the polyfunctional monomer (component B). Both coated wires were passed through a baking furnace with a furnace length of 6 m and heat treated under the conditions shown in Table 2 to obtain an insulated wire. The thickness of the resin film of each insulated wire was 28 to 31 μm. Various properties of these insulated wires were measured according to JIS3210. The measurement results are shown in Table 2. In Table 2, H and HB listed in the chemical resistance column refer to pencil hardness, which is specified in the JIS standard (JIS C3003).
The higher the hardness, the higher the degree of crosslinking and the better the chemical resistance.

[Table] As shown in Table 2, when the line speed was increased from 4 m/min to 9 m/min, triallylisocyanurate (component B) was added as shown in Example 3 and Comparative Example 3. In the case of thermal crosslinking alone (Comparative Example 3), the line speed was too high and the crosslinking was insufficient, and its electrical properties failed the JIS standard for polyester insulated wires for magnet wires.
Furthermore, even when triallylisocyanurate (component B) is blended, if the heating temperature is 200°C (Comparative Example 4), crosslinking will be insufficient and crystallization will proceed, and the electrical properties will be It does not meet the standards. From this, it can be seen that it is necessary to heat the polyester resin (component A) to a temperature higher than its melting point in order to prevent crystallization. Further, even if triallyl isocyanurate (component B) is added, the product heat-treated in nitrogen (Comparative Example 5) still has insufficient crosslinking, and its electrical properties fail the JIS standard.
The effect of thermal crosslinking is as explained above for Examples 1 and 2 and Comparative Examples 1 and 2,
The effect of such thermal crosslinking is also clear from Example 3 and Comparative Examples 3, 4, and 5. Example 4 The same polyethylene terephthalate and triallylisocyanurate as in Example 1 were used in Example 1.
Blend in the same proportions, melt and blend at 270℃,
It was placed in a tank in a molten state. This tank has a diameter of
Pass the 0.85mm copper wire through the die and squeeze it at the exit to a thickness of 28mm.
A coating film of ~31μ was formed. This coated wire was then passed through an air atmosphere furnace with a furnace length of 5 m and a furnace temperature of 350°C at various line speeds, and the residence time in the furnace was varied as shown in Table 3, and the insulated wire thus obtained was tested. The gel fraction was measured in the same manner as in Example 1. The results are shown in Table 3. Comparative Example 6 The gel fraction was measured in the same manner as in Example 1 for an insulated wire obtained in the same manner as in Example 4, except that triallylisocyanurate was not blended. The results are shown in Table 3.

[Table] As is clear from the results shown in Table 3, the product containing triallyl isocyanurate (component B) (Example 4) had a gel fraction of 75.0% at a residence time of 20 seconds in the furnace. , the one without the blend (Comparative Example 6) was only 1.8%, and by blending triallylisocyanurate, the line speed in the furnace can be significantly improved. As described above, the method of the present invention allows the line speed to be significantly higher than that of thermal crosslinking alone, and therefore has great economic benefits in terms of manufacturing costs.

Claims (1)

[Scope of Claims] 1 (a) The main component is an ester bond consisting of an acid component mainly consisting of a dicarboxylic acid in which an aromatic group or a part thereof is replaced with an aliphatic group, and a diol component mainly consisting of an aliphatic diol. A substantially linear polyester resin (A) having two or more aliphatic unsaturated groups having at least one hydrogen atom at the carbon atom α-position with respect to the double bond in the molecule. and 1 to 30 parts by weight of a compound (B) which is substantially stable with respect to the polyester resin (A) under melt blending conditions with the polyester resin (A) per 100 parts by weight of the polyester resin (A). (b) heating this coating layer to a temperature equal to or higher than the melting point of the polyester resin (A) in an oxygen-containing atmosphere to reduce the gel fraction of the coating layer; A method for producing an insulated wire, characterized by crosslinking the wire to 20% or more.