JP2010140815A - Insulated wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulated wire in which adhesion performance between a conductor and a conductor coating is not deteriorated even by high temperature treatment. <P>SOLUTION: A resin composition which includes a resin other than epoxy resin such as polyamide resin, urethane resin, nitrile rubber 20-150 pts.wt. and a hardener such as diaminodiphenyl methane 3-30 pts.wt. against epoxy resin 100 pts.wt. is coated and baked on a conductor and a primer layer in which the epoxy resin is hardened by the hardener is formed. Then, an insulation layer having, as a main component, at least one kind or more of resin selected from a group of polyester imide, polyamide imide, polyester, and polyimide is formed on the upper layer of the primer layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an insulated wire.

  In light of the fact that insulation coating breaks in so-called windings of motors, etc., inadequate layering and poor grounding, etc., improve mechanical strength and workability, and improve adhesion to conductors such as core wires. It is required for insulated wires to be made.

  Under such circumstances, for example, Japanese Patent No. 3766447 (Patent Document 1) includes aromatic polyamide-based paints, polyimide-based paints, polyamide-imide-based paints, polyester-imide-based paints, polyester-based paints, polyurethane-based paints, and the like. Curability such as acetylenes, alkynols and amines as metal deactivators different from the film-forming resin, and second phenolic resin, epoxy resin and melamine resin different from the resin component in the paint. A coating material for forming an insulating film using a resin is disclosed.

  Japanese Patent Laid-Open No. 10-334735 (Patent Document 2) discloses a coating material for forming an insulating film containing a polyimide resin in which melamine is added to a polyimide resin. By applying and baking these resin paints on the surface of the conductor, an insulated wire having high mechanical strength such as high adhesion to the conductor and not easily damaged, and excellent workability can be obtained.

Japanese Patent No. 3766447 Japanese Patent Laid-Open No. 10-334735

  However, even when these insulating paints are used, when a large current flows through the insulated wire, the conductor generates heat, and the temperature rise causes softening or deterioration of the insulating coating, resulting in insufficient layer or poor grounding. May occur. Therefore, not only the adhesiveness and mechanical strength are high and the processability is excellent, but further heat resistance is desired.

  Moreover, in an insulated wire, after performing an impregnation varnish process or twisting a plurality of insulated wires, a fusion | bonding process between lines may be performed by heat processing. In this case, when the above-mentioned paint is used, in particular, when a melamine resin is used, after being exposed to a high temperature during the impregnation varnish treatment or the fusion treatment, the adhesion with the conductor is lowered, and only the film is stretched. In some cases, the conductor was exposed.

  This invention is made | formed in view of such a condition, Comprising: In an insulated wire which has an insulating layer, it aims at forming the insulating layer which adhesiveness does not fall by high temperature processing.

  Therefore, the present inventor made diligent efforts, and the above object was achieved by providing a primer layer in which a resin composition containing at least one resin other than an epoxy resin, a curing agent and an epoxy resin was applied and baked on a conductor. As a result, the present invention has been completed.

  According to the present invention, an insulated wire excellent in workability such as mechanical strength and flexibility is not deteriorated even when exposed to a high temperature such as varnish impregnation treatment or fusion treatment. Is provided.

  The present invention is an insulated wire having a conductor, a primer layer covering the conductor surface, and an insulating layer covering the primer layer, wherein the primer layer is at least one resin other than an epoxy resin, a curing agent, and an epoxy resin It is the layer formed by apply | coating and baking the resin composition containing this to a conductor.

  As a conductor used for the insulated wire of the present invention, a conductor similar to the conductor conventionally used for the insulated wire is used, and examples thereof include a copper wire and an aluminum wire.

  The epoxy resin used in the present invention is not particularly limited as long as it is a thermosetting synthetic resin having a reactive epoxy group at the terminal. Such epoxy resins include glycidyl ether type, glycidyl amine type, glycidyl ester type, and olefin oxidation type (alicyclic type), and any of these types may be used. As a glycidyl ether type, for example, an epoxy resin obtained from an epihalohydrin and an active hydrogen compound, specifically, a bisphenol epoxy resin obtained from a bisphenol and epichlorohydrin, a cresol such as orthocresol, and formaldehyde Examples thereof include a cresol novolac type epoxy resin, an ortho cresol novolac type epoxy resin, and a polyfunctional monomer type epoxy resin obtained from a polyfunctional monomer. A halogenated epoxy resin obtained by halogenating a part of these resins with bromine or the like is also preferably used.

  Examples of bisphenol include 2,2-bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) sulfide, and 2,2-bis. Examples include (4-hydroxyphenyl) sulfone, 3,4,5,6-dibenzo-1,2-oxaphosphan-2-oxide hydroquinone, and the like.

  Preferred examples of the bisphenol epoxy resin include a bisphenol A epoxy resin obtained from bisphenol A and epihalohydrin, a bisphenol F epoxy resin obtained from bisphenol F and epihalohydrin, and a bisphenol S epoxy obtained from bisphenol S and epihalohydrin. Resins are exemplified. Moreover, these various epoxy resins can be used not only independently but also by mixing two or more kinds of epoxy resins.

  Although it does not restrict | limit especially as an average molecular weight (weight average molecular weight) of an epoxy resin, From a viewpoint of improving heat resistance and adhesiveness, Preferably it is 10,000-100000, More preferably, it is 30000-80000.

  In the present invention, not only an epoxy resin but also at least one resin other than an epoxy resin is used. Examples of the resin include polyamide resin, polyurethane resin, nitrile rubber, polyester, and polyimide resin. Among these, from the viewpoint of forming a good primer layer, polyamide resin, polyurethane resin, and nitrile rubber are preferably used. These resins are not particularly limited, and one or more of these resins can be used. Examples of the polyamide resin include nylon 6, nylon 66, nylon 11, nylon 12, nylon 610, nylon 612, and polyamide elastomer. As the polyurethane resin, any of polyester-based polyurethane (adipate-based, caprolactone-based, polycarbonate-based, etc.) and polyether-based polyurethane can be used. Nitrile rubber is a copolymer of butadiene and acrylonitrile. In the present invention, not only this copolymer but also hydrogenated nitrile rubber (HNBR) obtained by adding hydrogen thereto, carboxylated NBR introduced with methacrylic acid. Various derivatives of the copolymer such as (XNBR), NBIR in which part of butadiene is replaced with isoprene, and NIR in which all of butadiene is replaced with isoprene are also preferably used. Resins other than these epoxy resins are at least 10 parts by mass, more preferably at least 20 parts by mass with respect to 100 parts by mass of the epoxy resin, and the upper limit is at most 200 parts by mass, preferably at most 150 parts by mass. More desirably, it is 100 parts by mass or less. Within this range, a primer layer with good adhesion can be formed.

  In the present invention, it is not sufficient to apply and bake a resin composition containing these epoxy resins and resins other than epoxy resins, and it is necessary to cure these resin compositions using a curing agent. In this respect, as described in Patent Document 1, it is completely different from a resin layer in which a curable resin such as an epoxy resin is simply blended. This curing agent functions to form a three-dimensional network structure by reacting with an epoxy resin, and the curing agent is not particularly limited as long as it can perform this function. Various curing agents widely used as curing agents for epoxy resins, such as urea and melamine compounds, aliphatic amines and amine compounds, isocyanate compounds, aminopolyamide resins, alicyclic acid anhydrides such as methyltetrahydrophthalic anhydride Other examples include aliphatic acid anhydrides and aromatic acid anhydrides. These curing agents are appropriately selected in accordance with the characteristics of the target insulated wire, but in consideration of the object of the present invention, among these, amine compound and isocyanate compound curing agents are preferably used. . In the present invention, a part or all of the epoxy resin may be cured by a curing agent, and the primer layer of the present invention is formed by intricately intertwining a cured epoxy resin and a resin other than the epoxy resin. It is considered a thing.

  The amine compound used as the curing agent may be either an aliphatic amine or an aromatic amine. For example, metaphenylenediamine (MPDA), diaminodiphenylmethane (DDM), diaminodiphenylsulfone (DDS), methylenebis (2-chloroaniline), Aromatic amines such as methylenebis (2,3-dichloroaniline), diphenyldiaminosulfone, 2,2 ′, 3,3′-tetrachloro-4,4′-diaminodiphenylmethane, diethylenetriamine (DTA), triethylenetetramine (TTA) ), Tetraethylenepentamine, dipropylenediamine (DPDA), linear aliphatic polyamines such as diethylaminopropylamine (DEAPA), N-aminoethylpiverazine (NAEP), mensendiamine (MDA), isophorone diamine (IPDA) cycloaliphatic polyamines, such as, m- xylylenediamine (m-XDA), xylylenediamine, aliphatic aromatic amines such as xylylenediamine triplets are exemplified.

  Examples of the melamine compound include methylated melamine, butylated melamine, methylolated melamine, and butyrololized melamine.

  As isocyanate compounds, aromatic diisocyanates such as tolylene diisocyanate (TDI), diphenylmethane isocyanate (MDI), p-phenylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexane diisocyanate, lysine diisocyanate C3-C12 aliphatic diisocyanate such as 1,4-cyclohexane diisocyanate (CDI), isophorone diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI), methylcyclohexane diisocyanate, isopropylidene dicyclohexyl- 4,4′-diisocyanate, 1,3-diisocyanatomethylcyclohexane (hydrogenated XDI), 5 to 5 carbon atoms such as TDI, 2,5-bis (isocyanatomethyl) -bicyclo [2,2,1] heptane, 2,6-bis (isocyanatomethyl) -bicyclo [2,2,1] heptane Examples thereof include aliphatic diisocyanates having an aromatic ring such as 18 alicyclic isocyanates, xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), and modified products thereof. The above curing agents can be used alone or in admixture of two or more compounds.

  In the present invention, considering application to a conductor, it is generally used as a resin composition in which an epoxy resin or the like is mixed in an organic solvent as described later. In view of the stability at this time, a blocked isocyanate type curing agent is also preferably used.

  The blocked isocyanate is obtained by protecting the isocyanate compound with a blocking agent. Examples of the blocking agent include alcohols, phenols, ε-caprolactam, butyl cellosolve and the like, but are not limited thereto. Examples of alcohols include aliphatic alcohols having about 1 to 4 carbon atoms such as methanol, ethanol, propanol and butanol, aromatic alcohols such as benzyl alcohol, and alicyclic alcohols such as cyclohexanol. Examples of phenols include phenol, cresol, xylenol, and the like, but alcohols are preferably used as a blocking agent from the viewpoint of handleability.

  In the present invention, it is necessary to cure such a curing agent and an epoxy resin, but the amount ratio of the epoxy resin and the curing agent is appropriately determined in consideration of the characteristics of the obtained resin layer. That is, if the amount of the curing agent is small, the mechanical strength and heat resistance may be insufficient, and if the amount is large, there is a possibility that the resin layer becomes unfavorable because processability decreases. Therefore, in the present invention, the curing agent is at least 3 parts by mass, more preferably at least 5 parts by mass, and even more preferably at least 20 parts by mass with respect to 100 parts by mass of the epoxy resin. It is not more than part by weight, preferably not more than 150 parts by weight, more desirably not more than 100 parts by weight, and may be not more than 50 parts by weight.

  In this invention, the said component is provided as a resin composition uniformly disperse | distributed to the organic solvent, and a resin layer is formed by apply | coating and hardening the said resin composition on the conductor surface. The organic solvent used is not particularly limited. Examples of the organic solvent include polar organic solvents such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, tetramethylurea, hexaethylphosphoric triamide, and γ-butyrolactone. First, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, esters such as methyl acetate, ethyl acetate, butyl acetate, diethyl oxalate, diethyl ether, ethylene glycol dimethyl ether, diethylene glycol monomethyl ether, ethylene glycol monobutyl ether (butyl cellosolve) ), Ethers such as diethylene glycol dimethyl ether and tetrahydrofuran, charcoal such as hexane, heptane, benzene, toluene and xylene Examples include hydrogen, halogenated hydrocarbons such as dichloromethane and chlorobenzene, phenols such as cresol and chlorophenol, and tertiary amines such as pyridine. These organic solvents may be used alone or in combination of two or more. Used.

  The amount of the organic solvent is not particularly limited, and may be an amount that can uniformly disperse the epoxy resin and other resins and the curing agent. Usually, it is 5 parts by mass or more, preferably 10 parts by mass or more, and more preferably 30 parts by mass or more with respect to 100 parts by mass of the epoxy resin, but if it is too much, an appropriate coating film cannot be formed. From the viewpoint, it is at most 200 parts by mass, preferably 150 parts by mass or less, more preferably 100 parts by mass or less.

  In order to improve fluidity of fillers such as silica other than alumina, magnesium oxide, silicon carbide, and titanium carbide, and insulating paint, as required, within a range where the object of the present invention is not hindered. For example, titanium compounds such as tetraisopropyl titanate, tetrabutyl titanate, tetrahexyl titanate, zinc compounds such as zinc naphthenate and zinc octenoate, additives such as curing accelerators, antioxidants and leveling agents may be blended. There is no problem. From the viewpoint of obtaining a uniform dispersed resin composition upon mixing of alumina, it can be said that it is preferable to disperse in an organic solvent in advance and then mix with an epoxy resin dispersion.

  This resin composition is applied to the conductor surface and cured to form a primer layer. The coating method is not particularly limited, and for example, a conventional method such as a dipping method is used. After application, the primer layer is formed by naturally drying or heat drying the coating film at a temperature of from room temperature to 300 to 400 ° C. From the viewpoint of sufficiently reacting the epoxy resin and the curing agent and bringing the primer layer into close contact with the conductor surface, it is preferable to bake after applying the resin composition on the conductor rather than natural drying. Baking can be performed by a conventional method. The baking temperature is 150 to 400 ° C., preferably 200 to 400 ° C., from the viewpoint of preventing the reaction between the epoxy resin and the curing agent and the deterioration of the insulating layer due to the high temperature treatment. Moreover, when using blocked isocyanate as a hardening | curing agent, in order to make a blocking agent dissociate and to function as a hardening | curing agent, it is preferable to heat to the temperature more than the dissociation temperature. Moreover, baking may be performed only once or may be performed twice or more.

  The primer layer thus obtained can be used as the outer skin as it is, but it is exclusively used from the viewpoint of use as a winding, heat resistance, wear resistance, mechanical strength, oil resistance, chemical resistance, insulation, etc. One or a plurality of other insulating layers are formed on the primer layer. From such a viewpoint, the film thickness of the primer layer obtained by curing the epoxy resin or the like is set to the same thickness as that when the conventional ester imide resin or the like is used as the primer layer. Specifically, the resin composition is applied so that the thickness of the primer layer (thickness after baking) is 0.5 to 5 μm, preferably 1 to 5 μm.

  For the insulating layer laminated on the primer layer, various known insulating paints conventionally used for coating insulated wires, such as polyesterimide, polyamideimide, polyester and polyimide, are used. These resins can be used alone or in combination of two or more resins. In addition, the laminated insulating layer only needs to use these resins as a main component. In addition to these resins, other resins and additives may be added for the purpose of improving heat resistance, improving wear resistance, and slipping properties. It does not mean to exclude the mixed insulating layer. It is also possible to provide various known lubricating layers on top of these insulating layers in order to impart lubricity. In the present invention, these insulating layers are provided on the upper layer of the primer layer obtained by curing the epoxy resin, but the forming method is not different from the conventional method. Needless to say, the laminated insulating layer is not limited to one layer, and a plurality of layers may be laminated.

  Moreover, although the film thickness of the insulating layer provided in an upper layer can also be determined suitably, it is about 20-200 micrometers normally as a whole resin layer (including a primer layer) of an insulated wire, Preferably it is about 20 micrometers-100 micrometers in film thickness. It is formed.

  Thus, since the primer layer of the present invention is formed by applying and baking a resin composition containing at least one resin other than an epoxy resin, a curing agent and an epoxy resin on the conductor, the primer layer and the conductor Thus, an insulated wire having good mechanical strength with no separation from a conductor even during high-temperature treatment such as varnish impregnation treatment or fusion treatment is provided.

  Next, the present invention will be described in more detail based on the following examples. First, 50 parts by mass of bisphenol A type epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., product name Epicoat 1001) and 100 parts by mass of polycarbonate polyol (manufactured by Sumitomo Bayer Urethane Co., Ltd., product name Dismophen 2020E) as epoxy resins And 50 parts by mass of a urethane prepolymer obtained by reacting 25 parts by mass with methylene diisoionate (Sumitomo Chemical Co., Ltd., product name Sumidur 44S) and 25 parts by mass of diaminodiphenylmethane as a curing agent were dissolved in N-methylpyrrolidone. Thus, a resin composition having a solid content of 30% by mass was obtained.

  A primer layer obtained by applying this resin composition to a surface of a copper wire having a diameter of 1.0 mm so that the film thickness after baking is 3 μm, and baking and curing for several seconds in a baking furnace set at a furnace temperature of 300 to 400 ° C. Formed.

  Next, a resin solution of a general-purpose polyesterimide resin (general-purpose EsI: manufactured by Hitachi Chemical Co., Ltd., trade name Isomid 40SM-45) is applied so that the film thickness after baking is 22 μm, and the furnace temperature is 300 to 300 μm. The second resin layer was formed by baking for several seconds in a baking oven set at 400 ° C.

  Furthermore, general-purpose PAI was applied so that the film thickness after baking was 5 μm, and a third resin layer was formed under the same conditions as for general-purpose EsI. In addition, the general purpose PAI used what was obtained by the following method.

(Manufacture of general-purpose PAI)
Under a nitrogen gas environment, 176.9 g of trimellitic anhydride, 1.95 g of trimellitic acid and 233.2 g of methylene diisocyanate were charged into the flask, and 536 g of N-methyl-2-pyrrolidone was added as a solvent while stirring. After heating at 80 ° C. for 3 hours, the temperature in the flask was raised to 120 ° C. over about 4 hours and heated at the same temperature for 3 hours. Thereafter, the heating was stopped, 134 g of xylene was added to the flask, and then allowed to cool to obtain a polyamideimide resin varnish (general-purpose PAI) having a nonvolatile content of 35% by mass.

  Finally, a self-lubricating PAI that enhances lubricity is applied so that the film thickness after baking is 2 μm, and under the same conditions as the general-purpose EsI, a fourth resin layer is formed as a surface layer. The insulated wire of Example 1 was manufactured. The self-lubricating PAI was obtained by the following method.

(Manufacture of self-lubricating PAI)
Polyamide wax varnish (self-lubricating PAI) was obtained by mixing 1.5 parts by mass of polyethylene wax with respect to 100 parts by mass of the solid content of general-purpose PAI obtained above.

  15 parts by mass of novolak type epoxy resin (epoxy equivalent 200 g / eq o-cresol novolak type epoxy resin) and brominated epoxy resin (epoxy equivalent 625 g / eq, bromine content 51% brominated bisphenol A type epoxy resin) ) 130 parts by mass and 300 parts by mass of a brominated phenoxy resin (a brominated phenoxy resin having a weight average molecular weight of 30000 and a bromine content of 25%) and a polyamide resin (copolymerized polyamide resin having a glass transition temperature of 25 ° C and a melting point of 115 to 125 ° C) ) 100 parts by mass, 20 parts by mass of diphenyldiaminosulfonic acid as a curing agent, and 2 parts by mass of 2-undecylimidazole as a curing accelerator are dissolved in N-methylpyrrolidone, and the resin composition has a solid content of 30% by mass. I got a thing. And the insulated wire of Example 2 was manufactured like Example 1 below.

  As epoxy resin, brominated bisphenol A type epoxy resin (Japan Epoxy Resin Co., Ltd., product name EP5046) 56 parts by mass and bisphenol A type epoxy resin (Japan Epoxy Resin Co., Ltd., product name EP828) 14 parts by mass. And 15 parts by mass of carboxylated NBR (manufactured by Nippon Zeon Co., Ltd., trade name 1072J) and 15 parts by mass of carboxylated NBR (manufactured by Ube Industries, Ltd., trade name CTBN1300X13), and 2,2 ′ as a curing agent , 3,3′-tetrachloro-4,4′-diaminodiphenylmethane (Ihara Chemical Industry Co., Ltd., trade name TCCAM) and 2 undecylimidazole (Shikoku Kasei Co., Ltd.) as a curing accelerator Manufactured, trade name CURAZOLE C11Z) 0.6 parts by mass and 1,2,4-benzenetricarboxylic acid ( Mitsubishi Gas Chemical Co., Ltd., by dissolving the trade name F-TMA) 0.6 parts by weight N- methylpyrrolidone, to give a solid content of 30% by weight of the resin composition. And the insulated wire of Example 3 was manufactured like Example 1 below.

  Further, as a comparative example, as an alternative to the primer layer, a general-purpose polyesterimide varnish (general-purpose EsI: manufactured by Hitachi Chemical Co., Ltd., trade name Isomid 40SM-45) and a high-adhesion type polyesterimide varnish (high-adhesion EsI: Insulated electric wires (Comparative Example 1 and Comparative Example 2) each having a primer layer were produced using Dainichi Seika Kogyo Co., Ltd., trade name EH402-45 No. 3). And about the insulated wire of each Example and each comparative example, the test was done about unidirectional abrasion, film | membrane floating, and scratching load. The results are summarized in Table 1. In each test, six insulated wires were prepared in each example and each comparative example, and the average value of the obtained measured values was shown for those that could be evaluated numerically.

[One-way wear]
JIS C3003 9. The test was conducted according to wear resistance.

[Adhesion test]
JIS C3003 8. Adhesion 8.1a) According to the case of rapid extension, film floating (average value when measured at two points: average value of film floating) and length of conductor exposure (average value when measured at two points) : Conductor exposure average). Tests were stored at room temperature (adhesion at room temperature), heated for 1 hour in a constant temperature room at 200 ° C. (adhesion A after heating), and heated for 1 hour in a constant temperature room at 210 ° C. (adhesion after heating) B), heated for 6 hours in a constant temperature room at 160 ° C. (adhesiveness C after heating), and heated for 6 hours in a constant temperature room at 180 ° C. (adhesiveness D after heating).

[Scratch load test]
An insulated wire is set vertically to an Igetalloy wire (Sumitomo Electric Industries, Ltd.) having a diameter of 1.0 mm, a horizontal load is applied to the insulated wire from above, and then the insulated wire is pulled out, and JIS C3003 6). C) Uniformity test c) A test was conducted according to the pin pole method, and the bruising of the wound reaching the conductor was examined three times for each load, and the limit load when no pinhole was generated was examined.

  From the above results, it can be said that the mechanical strength (one-way friction) and the adhesiveness are improved as compared with the case where a highly adhesive polyesterimide or a general-purpose polyesterimide is used as the primer layer.

  As described above, the insulated wire of the present invention has high mechanical strength, and even when heated to a high temperature such as varnish impregnation treatment, the adhesion and mechanical strength are well maintained. Insulated wires that can handle high-power motors are provided.

  The embodiments and examples shown above are exemplifications, and the present invention is not limited to the embodiments and examples described above, and is included in the scope of the claims and all equivalents thereto. Are intended to be included in the present invention.

Claims (5)

An insulated wire having a conductor and a primer layer covering the conductor surface and an insulating layer covering the primer layer,
An insulated wire, wherein the primer layer is a layer formed by applying and baking a resin composition containing at least one resin other than an epoxy resin, a curing agent, and an epoxy resin on a conductor.   The insulated wire according to claim 1, wherein the resin composition contains a hardener in an amount of 3 to 30 parts by mass with respect to 100 parts by mass of the epoxy resin.   The insulated wire according to claim 1 or 2, wherein the resin other than the epoxy resin is at least one of a polyamide resin, a polyurethane resin, and a nitrile rubber.   The insulated wire according to any one of claims 1 to 3, wherein the resin composition contains a resin other than an epoxy resin in an amount of 20 to 150 parts by mass with respect to 100 parts by mass of the epoxy resin.   The insulated wire according to any one of claims 1 to 4, wherein the insulating layer mainly includes at least one resin selected from the group consisting of polyesterimide, polyamideimide, polyester, and polyimide.