TW202018023A - Polyimide varnish and preparation method thereof, polyimide coating article and preparation method thereof, wire and eleectronic device - Google Patents

Abstract

The present invention is a polyimide varnish for coating a conductor, which comprises: a polyamic acid solution produced by polymerizing at least one dianhydride monomer and at least one diamine monomer in an organic solvent; a silicone additive; an alkoxy silane coupling agent; and a low-temperature curing agent, wherein the softening resistant degree of the coated product produced from the polyimide varnish is at least 500 DEG C.

Description

Polyimide varnish and preparation method thereof, polyimide coated product and preparation method thereof, electric wire and electronic device

The present invention relates to a polyimide varnish for conductor coating for improving the heat resistance of polyimide coated products and a polyimide coated product prepared from the above polyimide varnish.

The insulating layer (insulating coating) of the coated conductor requires excellent insulation, adhesion to the conductor, heat resistance, mechanical strength, etc.

In addition, high-voltage electrical equipment, such as motors used at high voltages, apply high voltages to the insulated wires that make up the electrical equipment. Therefore, partial discharge (corona discharge) is likely to occur on the surface of the insulating coating .

Corona discharge can cause local temperature rise, or generate ozone or ions. As a result, the insulation coating of the insulated wire deteriorates, so the insulation damage is caused earlier and the life of the electrical equipment becomes shorter.

An insulated wire used at a high voltage requires improvement of the corona discharge starting voltage due to the above reasons. For this reason, it is known that it is effective to lower the dielectric constant of the insulating layer.

Examples of the resin that can be used for the insulating layer include polyimide resin, polyimide amide imide resin, and polyester amide imide resin.

Among them, polyimide resins, as materials with excellent heat resistance and insulation, have excellent properties as coating materials for conductors.

Polyimide resin refers to a highly heat-resistant resin prepared by polymerizing an aromatic dianhydride with an aromatic diamine or an aromatic diisocyanate solution to prepare a polyamic acid derivative, and then using Polyamide derivatives are closed-loop dehydrated and imidate.

As a method of forming an insulating coating using such a polyimide resin, for example, the following method may be used: a polyimide varnish that is a precursor of the polyimide resin is coated or coated around the wire including a conductor, and thereafter The polyimide varnish is imidized in a hardening furnace capable of heat treatment at a specific temperature.

This method of forming an insulating coating may vary in terms of physical properties, productivity, and preparation costs of the prepared insulating coating according to the conditions of the temperature of the hardening furnace, the number of times the polyimide varnish is applied, and the coating speed. That is, forming an insulating coating at a high temperature is advantageous for producing an insulating coating with excellent physical properties. The fewer the number of coatings or the faster the coating speed, the more the productivity will increase.

However, when the temperature of the hardening furnace is too high, it may cause defects in the surface of the prepared insulating coating or carbonization of the polyimide resin. When the above coating frequency is too small or the coating speed is too fast ，It will cause the problem that the physical properties of the prepared polyimide coated products decrease.

In addition, even if the ordinary polyimide resin has excellent physical properties, the adhesion to the conductor is not excellent. Therefore, when forming an insulating coating, a problem of poor appearance may occur.

As described above, it is very difficult to improve the characteristics required for the polyimide varnish and the polyimide resin prepared from the polyimide varnish. In particular, in the case where one characteristic is improved, the other characteristic is reduced, so , While satisfying multiple characteristics at the same time is a subject of continuous research in related technical fields.

Therefore, there is an urgent need for a polyimide varnish for conductor coatings that is excellent in productivity and process efficiency as described above, satisfies the heat resistance, insulation and mechanical properties of polyimide, and has excellent adhesion to conductors. .

[Problem to be solved by invention]

An object of the present invention is to provide a polyimide varnish for conductor coating including a surface conditioner, a coupling agent and a hardener, and a polyimide coating product prepared from the polyimide varnish.

According to one aspect of the present invention, surface modifiers, coupling agents, and hardeners are disclosed as necessary to realize polyimide-coated products having excellent heat resistance, insulation, flexibility, and adhesion to substrates (conductors) factor.

Therefore, the essential object of the present invention is to provide specific examples of the above-mentioned polyimide varnish for conductor coating.

[Means to solve the problem]

The invention provides a polyimide varnish, which is a polyimide varnish for conductor coating, which includes a polyamic acid solution, a silicone additive, an alkoxysilane coupling agent, and a low-temperature hardener. The polyamic acid solution is prepared by polymerizing more than one dianhydride monomer and more than one diamine monomer in an organic solvent. The coating products prepared from polyimide varnish have a softening resistance of 500°C or higher.

In an embodiment of the present invention, relative to 100 parts by weight of the solid content of the polyimide varnish, 0.01 to 0.05 parts by weight of the silicone-based additive is included.

In an embodiment of the invention, the silicone additives include selected from dimethylpolysiloxane, polyether modified polydimethylsiloxane, polymethylalkyl Polymethylalkylsiloxane and more than one group of silicone compounds including hydroxyl (-OH) and carbon-carbon double bond structure (C=C).

In an embodiment of the present invention, relative to 100 parts by weight of the solid component of the polyimide varnish, 0.01 to 0.05 parts by weight of the alkoxysilane coupling agent is included.

In an embodiment of the present invention, the alkoxysilane coupling agent includes a group selected from 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldi Methoxysilane, 3-aminopropylmethyl diethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane , More than one of the group consisting of 2-aminophenyltrimethoxysilane and 3-aminophenyltrimethoxysilane.

In an embodiment of the present invention, relative to 100 parts by weight of the solid component of the polyimide varnish, 0.1 to 2 parts by weight of the low temperature hardener is included.

In an embodiment of the invention, the low-temperature hardener includes one or more selected from the group consisting of β-picoline, isoquinoline, triethylidene diamine, and pyridine.

In an embodiment of the present invention, the low-temperature hardener includes one or more selected from the group consisting of β-picoline, isoquinoline, and pyridine and triethylidene diamine.

In an embodiment of the present invention, the dianhydride monomer includes one or more selected from the group consisting of pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarboxylic dianhydride.

In an embodiment of the present invention, the diamine monomer includes a group selected from the group consisting of 4,4'-diaminodiphenyl ether (or oxydiphenylamine) and 4,4'-methylenediphenylamine More than one.

In an embodiment of the invention, the polyimide varnish further includes an antioxidant.

In an embodiment of the present invention, the decomposition temperature of 5% by weight of the antioxidant is 380°C or higher.

In an embodiment of the present invention, relative to 100 parts by weight of the solid component of the polyimide varnish, 0.1 to 2 parts by weight of the antioxidant is included.

The invention provides a method for preparing a polyimide varnish, which is a method for preparing the above polyimide varnish, which includes (a) polymerizing more than one dianhydride monomer and more than one diamine monomer in an organic solvent and A process of preparing a polyamic acid solution; and (b) a process of mixing a silicone additive, an alkoxysilane coupling agent, and a low-temperature hardener in the polyamic acid solution.

In an embodiment of the present invention, the process (a) is performed at a temperature of 30°C to 80°C, the viscosity of the polyamic acid solution at a temperature of 23°C is in the range of 500 cP to 9,000 cP, and the process (b) is at a temperature Performed at 40°C to 90°C.

The invention provides a method for preparing a polyimide coating product, which includes (1) a process of applying the above polyimide varnish to a conductor surface; and (2) applying the polyimide varnish applied to the conductor surface The process of preparing the polyimide-coated product by the imidization of the amide-imide varnish and continuously performing the process (1) and the process (2) repeatedly 4 to 20 times, the polyimide-coated product The softening resistance temperature is above 500℃.

In an embodiment of the present invention, each time the process (1) and the process (2) are repeated once, the coating thickness of the polyimide varnish is 2 μm to 6 μm, and the process (2) is at a temperature of 300 Performed at ℃ to 750 ℃, the coating speed of the conductor is 2 m/min to 30 m/min.

In an embodiment of the invention, the conductor is a wire having a diameter of 0.1 mm to 5 mm.

The invention provides a polyimide-coated product, which is prepared by the preparation method of the polyimide-coated product.

In an embodiment of the invention, the thickness is in the range of 16 μm to 50 μm, the tan δ is 270°C or higher, and the dielectric breakdown voltage is 8 kV/mm or higher.

The present invention provides an electric wire, which includes a polyimide-coated product prepared by applying the above-mentioned polyimide varnish to the surface of the electric wire and performing imidization.

The invention provides an electronic device including the above electric wire

[Effect of the invention]

The alkoxysilane coupling agent and silicone additives in the polyimide varnish of the present invention can improve the adhesion between the polyimide coated product and the conductor and improve the production yield.

In addition, the low-temperature hardener included in the polyimide varnish is also used in the preparation process of polyimide coated products at relatively low hardening temperature and relatively few coating times or relatively low coating speed It can achieve a high imidization rate, which can improve the heat resistance, insulation, flexibility and other physical properties of polyimide coated products while improving productivity and process efficiency.

Such a polyimide-coated product has the advantages of satisfying the heat resistance, insulation and flexibility required by electronic devices, and has the advantage of excellent adhesion between the polyimide-coated product and the conductor.

The invention provides a polyimide varnish, which is a polyimide varnish for conductor coating, including: Polyamide acid solution is prepared by polymerizing more than one dianhydride monomer and more than one diamine monomer in an organic solvent; Silicone additives; Alkoxysilane coupling agent; and Low temperature hardener; and The coating products prepared from the above polyimide varnish have a softening resistance of 500°C or higher.

It was found that in the case of preparing a polyimide-coated product using the above-mentioned polyimide varnish, it has excellent heat resistance and insulation, and the flexibility of the coating and the adhesion to the substrate are improved.

Therefore, in this specification, the specific content for realizing the above-mentioned polyimide-coated product will be described.

Prior to this, the terms or words used in this specification and the patent application scope of the invention should not be limitedly interpreted as the ordinary meaning or the meaning in the dictionary. In order to explain their own invention in the best way, the inventor should only stand on The principles of the concept of the terminology can be appropriately defined and interpreted as meanings and concepts consistent with the technical idea of the present invention.

Therefore, the configuration of the embodiments described in this specification is only the best embodiment of the present invention, and does not represent all the technical ideas of the present invention. Therefore, it should be understood that there may be alternatives from the perspective of this application Various equivalents and modifications of the above embodiment.

In this specification, expressions in the singular include expressions in the plural as long as they do not express other meanings explicitly in the text. In this specification, it should be understood that the terms "including", "having", or "having" indicate the existence of implemented features, numbers, steps, constituent elements, or combinations thereof, and do not preclude one or more other features, numbers, The existence possibility or additional possibility of steps, constituent elements or combinations thereof.

In this specification, "dianhydride" refers to its precursors or derivatives, which are not technically dianhydrides, but even so, they also react with diamines to form polyamic acid, The above polyamic acid can be converted into polyimide again.

In this specification, "diamine" refers to those including their precursors or derivatives, which are not technically diamines, but even so, they also react with dianhydrides to form polyamic acid, and the above-mentioned polyamide The amine acid can be converted into polyimide again.

In this specification, when the amount, concentration, other value or parameter is listed as a range, a preferred range or a preferred upper limit value and a preferred lower limit value, it should be understood that it is irrelevant whether the range is disclosed otherwise Specifically, all ranges formed by an arbitrary pair of arbitrary upper range limit values or preferred values and arbitrary lower range limit values or preferred values are disclosed.

When a range of numerical values is mentioned in this specification, unless otherwise stated, the range is meant to include all integers and fractions within the end point and the range.

The scope of the invention is not limited to the specific values mentioned when defining the range.

First 1 Embodiment: Polyimide varnish

The polyimide varnish of the present invention is a polyimide varnish for conductor coating, which is characterized by including: Polyamide acid solution is prepared by polymerizing more than one dianhydride monomer and more than one diamine monomer in an organic solvent; Silicone additives; Alkoxysilane coupling agent; and Low temperature hardener; and The coating products prepared from the above polyimide varnish have a softening resistance of 500°C or higher.

In a specific example, the softening resistance temperature of the coated product prepared from the above polyimide varnish may be 500° C. or higher and 900° C. or lower.

On the other hand, the above polyimide varnish is based on the total weight of the polyimide varnish and the solid content may be 15% to 38% by weight, specifically 18% to 38% by weight, at 23°C The viscosity can be 500 cP to 8,000 cP, in detail 500 cP to 5,000 cP.

In the case where the solid content of the polyimide varnish is greater than the above range, the viscosity of the polyimide varnish will inevitably increase, which is not good.

Conversely, in the case where the solid content of the polyimide varnish is less than the above range, a large amount of solvent needs to be removed during the hardening process, thus causing problems of increased production cost and process time.

In addition, the polyimide varnish with the above viscosity has the advantage of being easy to handle in terms of fluidity, and will also facilitate the process of coating onto the conductor surface.

In detail, when the viscosity of the polyimide varnish is greater than the above range, when the polyimide varnish is moved by the tube in the preparation process of the polyimide, it needs to be applied due to friction with the tube The higher the pressure, the higher the process cost and the lower the handling.

In addition, when preparing polyimide coated articles, it may be difficult to uniformly apply to the conductor.

On the contrary, when the viscosity of the polyimide varnish is less than the above range, a large amount of solvent needs to be removed during the hardening process, which may cause problems of increased production cost and process time.

The alkoxysilane coupling agent may be included in an amount of 0.01 to 0.05 parts by weight relative to 100 parts by weight of the solid content of the polyimide varnish.

When the content of such an alkoxysilane coupling agent is greater than the above range, the mechanical properties will be reduced. When performing heat treatment to achieve imidization, the alkoxysilane coupling agent will decompose at high temperature and will instead The adhesion between the polyimide-coated product and the conductor is reduced, so it is not good.

Conversely, when the content of the alkoxysilane coupling agent is less than the above range, the effect of improving the adhesion between the polyimide-coated product and the conductor cannot be sufficiently exerted, which is not good.

The alkoxysilane coupling agent may include, for example, selected from the group consisting of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, 3 -Aminopropylmethyl diethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, 2-aminobenzene More than one of the group consisting of trimethoxysilane and 3-aminophenyltrimethoxysilane, but not limited to this.

The silicone-based additive may be included in an amount of 0.01 to 0.05 parts by weight relative to 100 parts by weight of the solid content of the polyimide varnish.

When the content of such silicone-based additives is greater than the above range, the mechanical properties of the prepared polyimide-coated product will be reduced. When performing heat treatment to achieve the imidization, the above-mentioned silicone-based additives The object decomposes at high temperature but will reduce the adhesion between the polyimide coated product and the conductor, which is not good.

Conversely, when the content of the silicone additive is less than the above range, the effect of improving the adhesion between the prepared polyimide-coated product and the conductor cannot be sufficiently exerted, which is not good.

The above-mentioned silicone additives may include, for example, selected from dimethylpolysiloxane, polyether modified polydimethylsiloxane (Polyether modified polydimethylsiloxane), and polymethylalkylsiloxane (Polymethylalkylsiloxane). , And one or more groups of silicone additives including hydroxyl (-OH) and double bond structure (C=C), but it is not limited to this.

The low-temperature hardener may be included in 0.1 to 2 parts by weight with respect to 100 parts by weight of the solid content of the polyimide varnish.

The low-temperature hardener may include one or more selected from the group consisting of β-picoline, isoquinoline, triethylenediamine, and pyridine.

Specifically, the low-temperature hardener may include one or more types selected from the group consisting of β-picoline, isoquinoline, and pyridine, and triethylenediamine.

In particular, the above-mentioned triethylenediamine functions to achieve low temperature hardening of the polyimide varnish and to improve the heat resistance of the prepared polyimide-coated product.

When the content of the low-temperature curing agent is greater than the above range, there is a high possibility of appearance defects caused by an increase in the curing rate, and the heat resistance and insulation of the polyimide coated product due to the difference in local curing rate However, physical properties such as flexibility will decrease. Conversely, when the content of the low-temperature hardener is less than the above range, the effect of the present invention for improving the heat resistance of the polyimide-coated product cannot be sufficiently exhibited, which is not good.

On the other hand, polyimide resins usually cause chemical changes, that is, oxidation reactions due to light, heat, pressure, shear force, etc. in the presence of oxygen. Such an oxidation reaction changes the physical properties due to molecular chain breakage and crosslinking in the polyimide resin, which causes a problem that the heat resistance and mechanical properties of the prepared polyimide film are reduced.

In the present invention, the polyimide varnish may further include an antioxidant to solve the above problems. Specifically, the decomposition temperature of 5% by weight of the above-mentioned antioxidant is 380° C. or more. Specifically, the decomposition temperature of 5% by weight may be 400° C. or more.

The above-mentioned antioxidant may include a compound represented by Chemical Formula 1 below.

In the above Chemical Formula 1, R ₁ to R ₆ may be independently selected from the group consisting of C1-C3 alkyl groups, aryl groups, carboxylic acid groups, hydroxyl groups, fluoroalkyl groups and sulfonic acid groups, n is 1 to 4 When R ₁ to R ₆ are plural, they may be the same or different from each other, and m 1 to m 6 are independently integers of 0 to 3.

In the above Chemical Formula 1, when the substituent of the benzene ring is not specified, the substituent refers to hydrogen.

In a specific example, in the above Chemical Formula 1, n may be 1, and m1 to m6 may be 0. In more detail, the antioxidant is a compound of the following Chemical Formula 1-1.

This kind of antioxidant has low volatility and excellent thermal stability, so it is not decomposed or volatilized in the preparation process of polyimide coated products, and can play a role in preventing the amide group or polyimide in the polyimide varnish Oxidation of amide imide groups of amine coated products.

Conversely, 5% by weight of an antioxidant with a decomposition temperature of 380° C. or lower decomposes due to high temperature in the production process of polyimide-coated products, so that the effect achieved by adding the above-mentioned antioxidant cannot be exerted.

The above-mentioned antioxidant can be included in the range of 0.1 part by weight to 2 parts by weight with respect to 100 parts by weight of the solid content of the polyimide varnish.

When the content of such an antioxidant is greater than the above range, deposition or blooming occurs in the polyimide-coated product and instead the mechanical properties are lowered, and the appearance of the coated product is unfavorable, which is not good .

Conversely, when the content of the antioxidant is less than the above range, the antioxidant effect cannot be sufficiently exhibited, which is not good.

On the other hand, as described above, the above-mentioned polyamic acid solution can be produced by the polymerization reaction of one or more dianhydride monomers and one or more diamine monomers.

The dianhydride monomer that can be used to prepare the polyamic acid of the present invention may be an aromatic tetracarboxylic dianhydride.

Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride (or PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (or BPDA), 2,3,3', 4'-biphenyltetracarboxylic dianhydride (or a-BPDA), oxydiphthalic dianhydride (or ODPA), diphenyl sulfone-3,4,3',4'-tetracarboxylic dianhydride (Or DSDA), bis(3,4-dicarboxyphenyl) sulfide dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexa Fluoropropane dianhydride, 2,3,3',4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride (or BTDA), double (3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, p-phenylene bis(trimellitic acid monoester anhydride), p-extrusion Biphenyl bis (trimellitic acid monoester anhydride), m-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, p-terphenyl-3,4,3',4'- Tetracarboxylic dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)phthalic anhydride, 1,4-bis(3,4-dicarboxyphenoxy)phthalic anhydride, 1,4- Bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA), 2,3,6, 7-Naphthalene tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 4,4'-(2,2-hexafluoroisopropylidene) diphthalic dianhydride, etc. These can be used alone or in combination of two or more as desired.

These can be used alone or in combination of two or more as desired, but in the present invention, the dianhydride monomer that can be preferably used may be selected from pyromellitic dianhydride (PMDA, pyromellitic dianhydride) and 3 ,3',4,4'-Biphenyl tetracarboxylic dianhydride (BPDA, tetracarboxylic dianhydrid) more than one of the ethnic group.

The diamine monomers that can be used to prepare the polyamic acid solution of the present invention can be listed as aromatic diamines as follows.

1) Such as 1,4-diaminobenzene (or p-phenylenediamine, PDA), 1,3-diaminobenzene, 2,4-diaminotoluene, 2,6-diaminotoluene, 3, 5-diaminobenzoic acid (or DABA) and other diamines with a benzene core in the structure are relatively strong diamines; 2) Such as 4,4'-diaminodiphenyl ether (or oxydiphenylamine, ODA), 3,4'-diaminodiphenyl ether and other diaminodiphenyl ether, 4,4'-diamine Diphenylmethane (or methylene dianiline, MDA), 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-di Aminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, bis(4- Aminophenyl) sulfide, 4,4'-diaminobenzylaniline, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine (or o-tolidine), 2 ,2'-dimethylbenzidine (or m-toluidine), 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-diaminedi Phenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl Thioether, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfide, 4,4'-diamine Phenylbenzene, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone , 3,3'-diamino-4,4'-dimethoxybenzophenone, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4, 4'-diaminodiphenylmethane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-amino Phenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 3,3'-diaminodiphenyl sulfite, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, etc. have 2 benzenes in structure Nuclear diamine; 3) Such as 1,3-bis(3-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(3-aminophenyl)benzene, 1, 4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene (or TPE-Q) , 1,4-bis(4-aminophenoxy)benzene (or TPE-Q), 1,3-bis(3-aminophenoxy)-4-trifluoromethylbenzene, 3,3' -Diamino-4-(4-phenyl)phenoxybenzophenone, 3,3'-diamino-4,4'-bis(4-phenylphenoxy)benzophenone, 1,3-bis(3-aminophenylsulfide)benzene, 1,3-bis(4-aminophenylsulfide)benzene, 1,4-bis(4-aminophenylsulfide)benzene , 1,3-bis(3-aminophenyl sulfonate)benzene, 1,3-bis(4-aminophenyl sulfonate)benzene, 1,4-bis(4-aminophenyl sulfonate)benzene, 1 ,3-bis[2-(4-aminophenyl)isopropyl]benzene, 1,4-bis[2-(3-aminophenyl)isopropyl]benzene, 1,4-bis[2 -(4-aminophenyl) isopropyl] benzene and other diamines having three benzene nuclei in structure; 4) Such as 3,3'-bis(3-aminophenoxy) biphenyl, 3,3'-bis(4-aminophenoxy) biphenyl, 4,4'-bis(3-amino group Phenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)biphenyl, bis[3-(3-aminophenoxy)phenyl]ether, bis[3-(4- Aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ether, bis[3 -(3-aminophenoxy)phenyl] ketone, bis[3-(4-aminophenoxy)phenyl] ketone, bis[4-(3-aminophenoxy)phenyl] ketone , Bis[4-(4-aminophenoxy)phenyl] ketone, bis[3-(3-aminophenoxy)phenyl] sulfide, bis[3-(4-aminophenoxy)phenyl ) Phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [3- ( 3-aminophenoxy) phenyl] satin, bis[3-(4-aminophenoxy) phenyl] satin, bis[4-(3-aminophenoxy) phenyl] satin, bis [4-(4-Aminophenoxy)phenyl] ash, bis[3-(3-aminophenoxy)phenyl]methane, bis[3-(4-aminophenoxy)phenyl ]Methane, bis[4-(3-aminophenoxy)phenyl]methane, bis[4-(4-aminophenoxy)phenyl]methane, 2,2-bis[3-(3- Aminophenoxy)phenyl]propane, 2,2-bis[3-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy) Phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2-bis[3-(3-aminophenoxy)phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis[3-(4-aminophenoxy)phenyl]-1,1,1,3,3,3- Hexafluoropropane, 2,2-bis[4-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-( 4-Aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane and other diamines having four benzene nuclei in structure.

These can be used alone or in combination of two or more as desired, but in the present invention, the diamine monomer that can be preferably used may be selected from 4,4′-diaminodiphenyl ether (or oxygen Diphenylamine (ODA) and 4,4'-methylenedianiline (MDA) in one or more groups.

First 2 Embodiment: Preparation method of polyimide varnish

The preparation method of the polyimide varnish of the present invention may include: (A) The process of preparing a polyamic acid solution by polymerizing more than one dianhydride monomer and more than one diamine monomer in an organic solvent; and (B) The process of mixing silicone additives, alkoxysilane coupling agent and low temperature hardener in the above-mentioned polyamide solution.

In the present invention, the preparation of the polyamic acid solution can be exemplified by the following methods, for example: (1) A method of putting the entire amount of the diamine monomer into the solvent, and thereafter adding the dianhydride monomer in such a way that it is substantially equivalent to the diamine monomer and polymerizing; (2) A method of putting the entire amount of dianhydride monomer into a solvent and then adding a diamine monomer so as to be substantially equivalent to the dianhydride monomer and polymerizing; (3) After putting a part of the components in the diamine monomer into the solvent, a part of the components in the dianhydride monomer are mixed at a ratio of about 80 mol% to 120 mol% relative to the reaction components, and then added A method of polymerizing the remaining diamine monomer component and continuously adding the remaining dianhydride monomer component to make the diamine monomer and the dianhydride monomer substantially equal moles; (4) After putting the dianhydride monomer in the solvent, a part of the components in the diamine compound is mixed at a ratio of 90 mol% to 110 mol% relative to the reaction component, and then other dianhydride monomer components are added , And continue to add the remaining diamine monomer component to make the diamine monomer and dianhydride monomer become substantially equivalent to the polymerization method; (5) A first composition is formed by reacting in excess of any of a part of the diamine monomer component and a part of the dianhydride monomer component, and a part of the diamine monomer component and a part of the dianhydride monomer Any one of the components is reacted in excess in another solvent to form the second composition, and then the first composition and the second composition are mixed to complete the polymerization. In this case, when the first composition is formed, When the amine monomer component is excessive, the dianhydride monomer component is excessive in the second composition, and when the dianhydride monomer component is excessive in the first composition, the diamine monomer component is excessive in the second composition The method of mixing the first composition and the second composition and using the whole diamine monomer component and the dianhydride monomer component used for the reaction thereof to be substantially equivalent to the polymerization method.

The organic solvent is not particularly limited as long as it can dissolve polyamic acid, but as an example, it may be an aprotic polar solvent.

Non-limiting examples of the aprotic polar solvent include N,N'-dimethylformamide (DMF), N,N'-dimethylacetamide (DMAc) and other amide-based solvents, P-chlorophenol, o-chlorophenol and other phenolic solvents, N-methyl-pyrrolidone (NMP), γ-butyrolactone (GBL) and diethylene glycol dimethyl ether (Diglyme), etc., which can be used alone Or a combination of two or more.

Auxiliary solvents such as xylene, toluene, tetrahydrofuran, acetone, methyl ethyl ketone, methanol, ethanol, water, etc. may also be used to adjust the solubility of the polyamic acid.

In one example, the organic solvent that can be preferably used to prepare the polyimide varnish of the present invention can be N,N'-dimethylformamide and N,N'-dimethyl which are amide-based solvents Acetamide.

The above-mentioned polymerization method is not limited to the above-mentioned example, and of course any known method can be used.

The above dianhydride monomer can be appropriately selected from the examples described above, and in detail, it can be preferably selected from pyromellitic dianhydride (PMDA, pyromellitic dianhydride) and 3,3',4,4'- More than one of the ethnic groups composed of biphenyl-tetracarboxylic dianhydrid (BPDA).

The above-mentioned diamine monomer can be appropriately selected from the examples described above. In detail, it can be preferably selected from 4,4′-diaminodiphenyl ether (or oxydiphenylamine, ODA) and 4, More than one of the ethnic group consisting of 4'-methylene dianiline (MDA).

The above process (a) can be performed at 30°C to 80°C, and the viscosity of the above polyamide solution at 23°C is in the range of 500 cP to 9,000 cP.

In addition, the above process (b) can be further mixed with an antioxidant in a polyamic acid solution and performed at 40°C to 90°C.

The silicone additives and alkoxysilane coupling agent included in the polyimide varnish can improve the adhesion between the polyimide coating product prepared from the polyimide varnish and the conductor. The polyimide The antioxidant included in the amine varnish can minimize the change in physical properties of the polyimide-coated article prepared from the above-mentioned polyimide varnish.

In addition, the low-temperature hardener included in the polyimide varnish can improve physical properties such as heat resistance, insulation, and flexibility of the polyimide-coated product prepared from the polyimide varnish.

However, the specific combination of the silicone additives, alkoxysilane coupling agents, antioxidants, and low-temperature hardeners included in the polyimide varnish and the slight difference in content will also make the physical properties of the polyimide coated products Changes have occurred, and it is not easy to speculate on the above changes.

First 3 Embodiment: Preparation method of polyimide coated products and polyimide coated products

The preparation method of the polyimide coating product of the present invention is characterized by including: (1) The process of applying polyimide varnish to the conductor surface; and (2) The process of imidizing the polyimide varnish coated on the conductor surface; and Continuously execute the above process (1) and process (2) 4 to 20 times, The softening resistance temperature of the polyimide-coated product is 500°C or higher.

Each time the above process (1) and process (2) are repeated once, the coating thickness of the above polyimide varnish may be 2 μm to 6 μm, The above process (2) is performed at 300°C to 750°C.

In addition, the coating speed of the above conductor may be 2 m/min to 30 m/min.

The above conductor may be a copper wire including copper or a copper alloy, but various metal plated wires such as silver wires and other metal materials or aluminum-plated wires and tin-plated wires may also be included as conductors.

The cross-sectional shape of the conductor may be loop wire, rectangular wire, hexagonal wire, etc., but it is not limited to this.

In the preparation method of the present invention, polyimide-coated products can be prepared by the thermal imidization method.

The thermal imidization method mentioned above refers to a method of excluding the chemical catalyst and inducing the imidate reaction using a heat source such as hot air or an infrared dryer.

The thermal imidization method described above can heat-treat the polyimide varnish at a variable temperature in the range of 100°C to 750°C to imide the amidinoyl group amide imide present in the polyimide varnish. In other words, it is possible to perform heat treatment at 300°C to 750°C, more specifically 500°C to 700°C to imidize the amidinate group present in the polyimide varnish.

The thickness of the polyimide-coated article of the present invention prepared according to the preparation method described above may be in the range of 16 μm to 50 μm, the softening resistance temperature is 500° C. or higher, the tan δ is 270° C. or higher, and the insulation breakdown voltage (BDV ) Is above 8 kV/mm.

The present invention can also provide an electric wire including a polyimide-coated product prepared by applying the above-mentioned polyimide varnish to the surface of the electric wire and performing imidization, and can provide an electronic device including the above-mentioned electric wire.

Hereinafter, the action and effect of the invention will be described in more detail with specific examples of the invention. However, these embodiments are only examples of the invention and do not thereby define the scope of rights of the invention.

Hereinafter, the compound names of abbreviations used in Examples and Comparative Examples are as follows. -Pyromellitic dianhydride: PMDA -Biphenyltetracarboxylic dianhydride: BPDA -Oxydiphenylamine: ODA -Methylene dianiline: MDA -N-methylpyrrolidone: NMP

<Example 1>

Nitrogen was injected into a 500 ml reactor equipped with a stirrer and a nitrogen injection/discharge pipe, and NMP was introduced, the temperature of the reactor was set to 30°C, and then ODA and PMDA were introduced to confirm complete dissolution.

After the temperature was raised to 50°C under a nitrogen atmosphere for heating and stirring was continued for 120 minutes, a polyamic acid solution having a viscosity of 10,000 cP at 23°C was prepared.

After setting the temperature of the reactor to 50°C, OFS-6011 as an alkoxysilane coupling agent and 5% by weight of an antioxidant were added to the above-mentioned polyamic acid solution at a weight ratio of 1:50:1:1 The compound of the following chemical formula 1-1 with a decomposition temperature of about 402°C, BYK-378 as a silicone additive, and triethylidene diamine as a low-temperature hardener are slowly stirred for 30 minutes to the total solid content The NMP content was about 25% by weight and the viscosity was about 3,000 cP. NMP was prepared to prepare a diamine monomer and dianhydride monomer with a molar ratio of 100:100 and 0.01 parts by weight relative to 100 parts by weight of the solid content. Polyimide varnish of alkoxysilane coupling agent, 0.5 parts by weight of antioxidant, 0.01 parts by weight of silicone additives, and 0.5 parts by weight of low temperature hardener.

In the coating and hardening furnace, when the above polyimide varnish is applied to a copper wire with a conductor diameter of 1 mm, the thickness of each coating is adjusted to be between 2 μm and 6 μm, and the coating and hardening furnace The maximum temperature is adjusted to 500 ℃, and the coating speed of the copper wire is adjusted to 12 m/min. The coating is repeated 7 times, the drying and hardening processes are carried out to prepare polyacrylic acid with a coating thickness of 35 μm. Amine-coated wire.

<Examples 2 to 13 and Comparative Examples 1 to 16>

Except that the viscosities of the monomers, additives, and polyimide varnish in Example 1 were changed as in Table 1 below, except that the electric wires were prepared in the same manner as in Example 1.

<Comparative Example 9>

It was prepared by the same method as Example 1 except that 5% by weight of the compound of the following Chemical Formula A having a decomposition temperature of about 377°C was substituted for the compound of Chemical Formula 1-1 in Example 1 as an antioxidant. wire.

<Comparative Example 10>

It was prepared by the same method as Example 1 except that 5 wt% of the compound of the following Chemical Formula B with a decomposition temperature of about 338°C was substituted for the compound of Chemical Formula 1-1 in Example 1 as an antioxidant. wire.

[Table 1]

<Experiment Example 1: Evaluation of poor appearance>

The appearance of the polyimide-coated products of the electric wires prepared in Examples 1 to 13 and Comparative Examples 1 to 16 was visually observed to determine whether they were defective, and the results are shown in Table 2 below.

For example, when it is a good-quality coated product, it is indicated as "○", and when a pinhole or polyimide resin carbonization is found to be poor in appearance, it is indicated as "×".

<Experimental Example 2: Thermal Shock Evaluation>

The polyimide-coated articles of the electric wires prepared in Examples 1 to 13 and Comparative Examples 1 to 16 were evaluated for thermal shock resistance. Thermal shock is an indicator of whether it can withstand exposure to temperature when the wire is expanded, or wrapped around the mandrel or bent.

Specifically, in order to evaluate the thermal shock resistance, the polyimide-coated articles of the electric wires prepared in Examples 1 to 13 and Comparative Examples 1 to 16 were heated at 200°C for 30 minutes to After the oven was taken out, the test piece was cooled to room temperature, and then the number of cracks generated in the polyimide-coated product at 20% elongation was judged, and the results are shown in Table 2 below.

[Table 2]

From the results in Table 2, it can be seen that a comparative example using a silicone additive, an alkoxysilane coupling agent, or a low-temperature hardener in a manner that deviates from the scope of the present invention cannot uniformly coat polyimide-coated products, Or carbonization occurs locally, and the thermal shock is weak.

<Experiment example 3: Physical property evaluation>

The physical properties of the polyimide-coated products of the electric wires prepared in Examples 1 to 13 and Comparative Examples 1 to 16 were measured in the following manner, and the results are shown in Table 3 below.

(1) tanδ value

The tan delta value of polyimide-coated articles was measured using TD300 tan delta tester (Dan Delta Tester) from DSE.

Specifically, the test piece is connected to the bridge with the conductor as one electrode and the graphite coating as the other electrode, and the temperature of the assembly is increased at a fixed rate from the ambient temperature to a temperature that provides a well-defined curve. The temperature was determined by a detector in contact with the sample, and the result was plotted as a linear axis versus temperature and logarithmic or linear axis graph against tan δ, and the tan δ value of the polyimide-coated article was calculated based on the above values.

(2) Resistance to softening temperature

The softening resistance temperature indicates the decomposition temperature of the insulator, and the temperature at which a short circuit occurs between two electric wires crossing each other at a right angle is measured in a state where a predetermined load is applied to the intersection point to determine the softening resistance temperature.

Specifically, the electric wires are stacked at right angles and placed on a flat plate, with a load of 1000 g applied to the overlapped portion, an AC voltage of 100 V is applied at a rate of about 2°C/min in this state The temperature is increased to measure the temperature of the short circuit.

(3) Insulation breakdown voltage (BDV)

The test piece was pretreated in an oven at 150°C for 4 hours, and then put into a pressure vessel. After filling the pressure vessel with 1400 g of refrigerant and heating the pressure vessel for 72 hours, the pressure vessel was cooled, and the test piece was transferred to an oven at 150° C. and held for 10 minutes to cool to room temperature. Connect the two ends of the wire, and increase the AC voltage at the nominal frequency of the test voltage (60 Hz) at a fixed speed between the wire conductors from 0 to determine BDV.

(4) Pinhole test

In order to confirm whether the insulator of the polyimide-coated product of the electric wire has defects, a pinhole test was conducted. Specifically, a wire test piece with a length of about 1.5 m is taken and placed in an air circulation oven (125° C.) for 10 minutes, and then cooled at room temperature without causing any bending or elongation. The cooled wire test piece was immersed in a sodium chloride electrolyte solution to which phenolphthalein alcohol was added while being connected to a circuit having a DC test voltage, and the number of pinholes was visually confirmed.

<Experiment example 4: tensile test>

In order to confirm the adhesion between the conductor and the coated product, the polyimide coated product of the electric wires prepared in Examples 1 to 13, and Comparative Examples 1 to 16 was subjected to a tensile test, and the results Shown in Table 3 below.

Specifically, a straight wire test piece having a freely measured length of 200 mm to 250 mm is quickly stretched to the point of failure or the length (20%) given in the corresponding standard. After elongation, check the test piece for adhesion loss or cracking at a specified rate (1 to 6 times). The 2 mm length of the damaged wire end should be ignored.

Test three test pieces. If the wire is cracked and/or loss of adhesive force, record this situation.

[table 3]

Referring to Table 3, the polyimide coated articles of Examples 1 to 13 prepared from the polyimide varnish of the present invention including silicone additives, alkoxysilane coupling agents, low temperature hardeners and antioxidants The tan δ is 270°C or higher, the softening temperature is 500°C or higher and the heat resistance is excellent, and the insulation breakdown voltage is 8 kV/mm or higher and the insulation is excellent. The tensile test confirmed the difference between the conductor and the coated product. The adhesion is excellent.

On the contrary, the following cases can be confirmed: Comparative Example 1 in which silicone additives, alkoxysilane coupling agent, low-temperature hardener, antioxidant and solid content, viscosity, and maximum temperature of the curing furnace are different from the examples At least one of tan δ, softening temperature resistance, or insulation breakdown voltage up to Comparative Example 16 is lower than that in Examples, and there are relatively many defects in the number of pinholes confirmed by the pinhole test, that is, insulators. In addition, it was confirmed that in some of the comparative examples, cracks were observed on the outer surface of the polyimide-coated product in the tensile test, and the adhesion between the conductor and the coated product decreased.

The above has been described with reference to the embodiments of the present invention, but those skilled in the art to which the present invention pertains can make various applications and modifications within the scope of the present invention based on the above.

no

no

Claims (22)

A polyimide varnish, which is a polyimide varnish for conductor coating, includes: Polyamide acid solution is prepared by polymerizing more than one dianhydride monomer and more than one diamine monomer in an organic solvent; Silicone additives; Alkoxysilane coupling agent; and Low temperature hardener, and The coating product prepared from the polyimide varnish has a softening resistance of 500°C or higher. The polyimide varnish as described in item 1 of the patent application scope, wherein, relative to 100 parts by weight of the solid component of the polyimide varnish, 0.01 parts to 0.05 parts by weight of the silicone-based additive is included . The polyimide varnish as described in item 1 of the patent application scope, wherein the silicone additives include selected from dimethylpolysiloxane (dimethylpolysiloxane), polyether modified polydimethylsiloxane ( Polyether modified polydimethylsiloxane), polymethylalkylsiloxane (Polymethylalkylsiloxane) and more than one group consisting of a silicone compound including a hydroxyl group (-OH) and a carbon-carbon double bond structure (C=C). The polyimide varnish as described in item 1 of the patent application scope, wherein, relative to 100 parts by weight of the solid component of the polyimide varnish, 0.01 to 0.05 parts by weight of the alkoxysilane coupling agent is included mixture. The polyimide varnish as described in item 1 of the patent application scope, wherein the alkoxysilane coupling agent comprises a group selected from 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane , 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3- More than one of the group consisting of phenylaminopropyltrimethoxysilane, 2-aminophenyltrimethoxysilane and 3-aminophenyltrimethoxysilane. The polyimide varnish as described in item 1 of the patent application scope, wherein the low temperature hardener is included in 0.1 to 2 parts by weight relative to 100 parts by weight of the solid component of the polyimide varnish. The polyimide varnish as described in item 1 of the patent application scope, wherein the low temperature hardener includes one selected from the group consisting of β-picoline, isoquinoline, triethylidene diamine and pyridine the above. The polyimide varnish as described in item 7 of the patent application scope, wherein the low temperature hardener includes one or more selected from the group consisting of β-picoline, isoquinoline and pyridine and triethylidene amine. The polyimide varnish as described in item 1 of the patent application scope, wherein the dianhydride monomers are selected from pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarboxylic dianhydride More than one of the ethnic groups formed. The polyimide varnish as described in item 1 of the patent application scope, wherein the diamine monomers include selected from 4,4'-diaminodiphenyl ether (or oxydiphenylamine) and 4,4'- More than one of the group consisting of methylene dianiline. The polyimide varnish as described in item 1 of the patent application scope further includes an antioxidant. The polyimide varnish as described in item 11 of the patent application range, wherein the decomposition temperature of 5 wt% of the antioxidant is 380°C or higher. The polyimide varnish as described in item 11 of the patent application range, wherein the antioxidant is included in 0.1 to 2 parts by weight relative to 100 parts by weight of the solid component of the polyimide varnish. A method for preparing polyimide varnish, which is a method for preparing polyimide varnish as described in item 1 of the patent application, includes: (A) The process of preparing a polyamic acid solution by polymerizing more than one dianhydride monomer and more than one diamine monomer in an organic solvent; and (B) The process of mixing silicone additives, alkoxysilane coupling agent and low-temperature hardener in the polyamic acid solution. The preparation method of polyimide varnish as described in item 14 of the patent application scope, wherein process (a) is performed at a temperature of 30°C to 80°C, The viscosity of the polyamide solution at a temperature of 23°C is in the range of 500 cP to 9,000 cP, Process (b) is performed at a temperature of 40°C to 90°C. A preparation method of polyimide coated products includes: (1) The process of applying the polyimide varnish as described in item 1 of the patent application scope to the conductor surface; and (2) The process of preparing the polyimide-coated product by imidizing the polyimide varnish applied to the surface of the conductor, and Continuously execute process (1) and process (2) repeatedly 4 to 20 times, The softening resistance temperature of the polyimide coated product is above 500°C. The method for preparing a polyimide coating product as described in item 16 of the patent application scope, wherein each time the process (1) and the process (2) are repeated once, the coating thickness of the polyimide varnish is 2 μm to 6 μm, Process (2) is performed at a temperature of 300°C to 750°C, The coating speed of the conductor is 2 m/min to 30 m/min. The method for preparing a polyimide-coated article as described in item 16 of the patent application range, wherein the conductor is an electric wire having a diameter of 0.1 mm to 5 mm. A polyimide-coated product prepared by the method for preparing a polyimide-coated product as described in item 16 of the patent application. Polyimide-coated products as described in item 19 of the patent application, whose thickness ranges from 16 μm to 50 μm, tanδ is above 270℃, The dielectric breakdown voltage is above 8 kV/mm. An electric wire comprising a polyimide coated article prepared by applying the polyimide varnish as described in item 1 of the patent application scope to the surface of the electric wire and performing imidization. An electronic device including the electric wire as described in item 21 of the patent application scope.