TWI736867B - Polyimide varnish and preparation method thereof, polyimide coating article and preparation method thereof, wire and eleectronic device - Google Patents

Abstract

The invention provides a polyimide varnish and a preparation method thereof, a polyimide coating product and a preparation method thereof, an electric wire and an electronic device. The invention provides a polyimide varnish, which is a polyimide varnish for conductor coating, which comprises a polyimide prepared by polymerizing more than one dianhydride monomer and more than one diamine monomer in an organic solvent Acid solution, silicone additives, alkoxysilane coupling agent and low-temperature hardening agent, and the softening resistance temperature of the coating product prepared from the polyimide varnish is above 500°C.

Description

Polyimide varnish and preparation method thereof, polyimide coating 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 coating products and a polyimide coating product prepared from the polyimide varnish.

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

In addition, it is suitable for high-voltage electrical equipment, such as motors used under high voltage. High voltage is applied to the insulated wires constituting the electrical equipment. Therefore, partial discharge (corona discharge) is likely to occur on the surface of the insulating coating. .

The occurrence of corona discharge may cause a local temperature rise, or generate ozone or ions. As a result, the insulation coating of the insulated wire is deteriorated. Therefore, the insulation breakdown occurs earlier and the life of electrical equipment is shortened.

Insulated wires used at high voltages are required to improve the corona discharge starting voltage for the above reasons. For this reason, it is known that reducing the dielectric constant of the insulating layer is effective.

Examples of resins that can be used for the insulating layer include polyimide resins, polyimide resins, and polyesterimide resins.

Among them, in particular, polyimide resin has excellent properties as a material having excellent heat resistance and insulation properties and used as a coating material for conductors.

Polyimide resin refers to a high heat-resistant resin prepared by the following method: after the aromatic dianhydride and the aromatic diamine or aromatic diisocyanate are solution polymerized to prepare the polyimide derivative, the above-mentioned The polyamide acid derivative is dehydrated by ring-closing and is imidized.

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

This method of forming an insulating coating may vary in terms of the physical properties, productivity, and preparation cost of the insulating coating prepared according to conditions such as the temperature of the curing furnace, the number of times of coating of the polyimide varnish, and the coating speed. That is, forming an insulating coating at a high temperature is beneficial to the production of an insulating coating with excellent physical properties. The fewer the number of coatings or the faster the coating speed, the more productivity will increase.

However, when the temperature of the above-mentioned curing furnace is too high, it will cause defects on the surface of the insulating coating or carbonization of the polyimide resin. When the above-mentioned number of coating times is too small or the coating speed is too fast , It will cause the problem of decreased physical properties of the prepared polyimide coating products.

In addition, even if a general polyimide resin has excellent physical properties, its adhesion to a conductor is not excellent. Therefore, when an insulating coating is formed, a problem of appearance defects occurs.

As described above, it is very difficult to improve the properties required of polyimide varnishes and polyimide resins prepared from the above polyimide varnishes. In particular, when one characteristic is improved, the other characteristic decreases, so To satisfy 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, and at the same time satisfies the heat resistance, insulation and mechanical properties of polyimide, and excellent adhesion to conductors. .

[The problem to be solved by the invention]

The purpose of the present invention is to provide a polyimide varnish for conductor coating comprising a surface modifier, a coupling agent and a hardener, and a polyimide coating product prepared from the polyimide varnish.

According to an aspect of the present invention, surface modifiers, coupling agents, and hardeners are disclosed as necessary to realize polyimide coated products with excellent heat resistance, insulation, flexibility, and adhesion to the substrate (conductor). 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 present invention provides a polyimide varnish, which is a polyimide varnish for conductor coating and includes a polyimide acid solution, silicone additives, alkoxysilane coupling agent and low-temperature hardener. The polyamide acid solution is prepared by polymerizing more than one dianhydride monomer and more than one diamine monomer in an organic solvent. The softening resistance temperature of the coated product prepared from the polyimide varnish is above 500°C.

In an embodiment of the present invention, relative to 100 parts by weight of the solid content of the polyimide varnish, 0.01 parts by weight to 0.05 parts by weight of the silicone additives are included.

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

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 alkoxysilane coupling agent is included.

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

In an embodiment of the present invention, relative to 100 parts by weight of the solid content of the polyimide varnish, the low-temperature hardener includes 0.1 to 2 parts by weight.

In an embodiment of the present invention, the low-temperature hardening agent includes more than one selected from the group consisting of β-picoline, isoquinoline, triethylenediamine, 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 triethylenediamine.

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

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

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

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

The present invention provides a method for preparing polyimide varnish, which is a method for preparing the above polyimide varnish, comprising (a) polymerizing more than one dianhydride monomer and more than one diamine monomer in an organic solvent. A process of preparing a polyamide acid solution; and (b) a process of mixing silicone additives, an alkoxysilane coupling agent and a low-temperature hardening agent in the polyamide 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 performed at a temperature Performed at 40°C to 90°C.

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

In an embodiment of the present invention, each time process (1) and 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 Executed at ℃ to 750℃, the coating speed of the conductor is 2 m/min to 30 m/min.

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

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

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

The present invention provides an electric wire, which comprises a polyimide coated product prepared by coating the above-mentioned polyimide varnish on the surface of the electric wire for imidization.

The present invention provides an electronic device, which includes the above-mentioned wire

[Effects 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 coating 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 the polyimide coating product at a relatively low hardening temperature and a relatively small number of coatings or a relatively low coating speed. A high imidization rate can be achieved, thereby improving the heat resistance, insulation, flexibility and other physical properties of polyimide coating products while improving productivity and process efficiency.

The polyimide coated product has the advantages of meeting 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 present invention provides a polyimide varnish, which is a polyimide varnish for conductor coating and includes: The 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 softening resistance temperature of the coated product prepared from the polyimide varnish is above 500°C.

It is found that when the polyimide varnish is used to prepare a polyimide coated product, 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 scope of patent applications for inventions should not be limitedly interpreted as ordinary meanings or dictionary meanings. In order for the inventor to explain his own invention in the best way, he should only be based on The principles of the concepts of terms can be appropriately defined and interpreted as meanings and concepts that conform to the technical idea of the present invention.

Therefore, the configuration of the embodiment 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-mentioned embodiment.

In this specification, as long as other meanings are not clearly expressed in the text, the expression of the singular number includes the expression of the plural number. In this specification, it should be understood that terms such as "include", "have" or "have" indicate the presence of implemented features, numbers, steps, constituent elements, or combinations thereof, and do not preclude one or more other features, numbers, The existence or additional possibilities of steps, constituent elements, or combinations thereof.

In this specification, "dianhydride" refers to those including its precursors or derivatives, which may not be dianhydrides technically, but even so, they also react with diamine to form polyamide acid. The above-mentioned polyamide can be converted into polyimide again.

In this specification, "diamine" refers to those including its precursors or derivatives, which may not be diamines technically, but even so, they also react with dianhydrides to form polyamide acid. Amino acids can be converted into polyimides again.

In this specification, when an amount, concentration, other value or parameter is listed as a range, a preferred range, or a preferred upper limit and a preferred lower limit, it should be understood that it has nothing to do with whether the range is otherwise disclosed. Specifically, all ranges formed by any pair of any upper range limit value or preferred value and any lower range limit value or preferred value are disclosed.

When the range of a numerical value is mentioned in this specification, unless otherwise stated, the range means the end point and all integers and fractions within the range.

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

NS 1 Implementation mode: Polyimide varnish

The polyimide varnish of the present invention is a polyimide varnish for conductor coating, and is characterized in that it includes: The 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 softening resistance temperature of the coated product prepared from the polyimide varnish is above 500°C.

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

On the other hand, the above-mentioned polyimide varnish is based on the entire 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, more specifically, 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, so it is not good.

On the contrary, when the solid content of the polyimide varnish is less than the above range, a large amount of solvent needs to be removed during the curing process, which causes problems of increased production cost and process time.

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

In detail, when the viscosity of the polyimide varnish is greater than the above range, the polyimide varnish needs to be applied due to friction with the tube when the polyimide varnish is moved by the tube during the preparation process of the polyimide The higher the pressure, so the process cost increases and the processability will decrease.

In addition, when preparing polyimide coated products, it may be difficult to uniformly coat 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 curing process, which causes problems of increased production costs and process time.

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

In the case where the content of the alkoxysilane coupling agent is greater than the above range, the mechanical properties will decrease. When the heat treatment for realizing the imidization is performed, the alkoxysilane coupling agent decomposes at high temperature and will instead The adhesion between the polyimide-coated product and the conductor is reduced, so it is not good.

On the contrary, when the content of the above-mentioned alkoxysilane coupling agent is less than the above-mentioned range, the effect of improving the adhesion between the polyimide-coated product and the conductor cannot be fully exhibited, and therefore it is not good.

The aforementioned alkoxysilane coupling agent may include, for example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, 3 -Aminopropylmethyldiethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, 2-aminobenzene One or more of the group consisting of trimethoxysilane and 3-aminophenyltrimethoxysilane, but it is not limited to this.

With respect to 100 parts by weight of the solid content of the polyimide varnish, 0.01 parts by weight to 0.05 parts by weight of silicone additives may be included.

When the content of such silicone additives is greater than the above range, the mechanical properties of the prepared polyimide coating products will decrease. When the heat treatment for achieving imidization is performed, the silicone additives are added The substance decomposes at high temperature, which will reduce the adhesion between the polyimide-coated product and the conductor, so it is not good.

On the contrary, when the content of the aforementioned silicone additives is less than the aforementioned range, the effect of improving the adhesion between the prepared polyimide-coated product and the conductor cannot be fully exerted, and therefore it is not good.

The aforementioned silicone additives may include, for example, selected from the group consisting of dimethylpolysiloxane, polyether modified polydimethylsiloxane, and polymethylalkylsiloxane. , And more than one group of silicone additives including hydroxyl (-OH) and double bond structure (C=C), but it is not limited to this.

With respect to 100 parts by weight of the solid content of the polyimide varnish, the low-temperature hardening agent may be included in an amount of 0.1 to 2 parts by weight.

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

Specifically, the above-mentioned low-temperature hardening agent may include one or more selected from the group consisting of β-picoline, isoquinoline, and pyridine, and triethylenediamine.

In particular, the above-mentioned triethylenediamine plays the role of realizing low-temperature hardening of the polyimide varnish and improving the heat resistance of the prepared polyimide coating product.

When the content of the above-mentioned low-temperature hardening agent is greater than the above-mentioned range, the appearance defect caused by the increase in the hardening speed is more likely to occur. The difference in the local hardening speed causes the heat resistance and insulation of the polyimide coated product , Flexibility and other physical properties will decrease instead. On the contrary, when the content of the above-mentioned low-temperature hardening agent is less than the above-mentioned range, the effect of the present invention for improving the heat resistance of the polyimide-coated product cannot be fully exhibited, and therefore it is not preferable.

On the other hand, polyimide resins generally 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 of the polyimide resin due to molecular chain scission, cross-linking, etc., thereby causing problems that the heat resistance and mechanical properties of the prepared polyimide film are reduced.

In the present invention, the above-mentioned polyimide varnish may further include an antioxidant to solve the above-mentioned problem. Specifically, the decomposition temperature of 5 wt% of the antioxidant is 380°C or higher, and in detail, the decomposition temperature of 5 wt% may be 400°C or higher.

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, aryl, carboxylic acid, hydroxyl, fluoroalkyl and sulfonic acid groups, and n is 1 to 4. The integers of R ₁ to R ₆ may be the same or different from each other when there are multiple R 1 to R 6, and m 1 to m 6 are each independently an integer of 0 to 3.

In the above chemical formula 1, when the substituent of the benzene ring is not specifically specified, the above 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. More specifically, the above antioxidant is a compound of the following Chemical Formula 1-1.

This antioxidant has low volatility and excellent thermal stability, so it will not decompose or volatilize during the preparation process of polyimide coating products, and can play a role in preventing the amide group or polyimide in the polyimide varnish. The effect of oxidation of the imine group of amine-coated products.

On the contrary, 5% by weight of the antioxidant with a decomposition temperature of 380°C or less decomposes due to high temperature during the preparation process of the polyimide coating product, and thus cannot exert the effect achieved by adding the above-mentioned antioxidant.

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

When the content of this antioxidant is greater than the above range, deposition or blooming will occur in the polyimide coated product, which will decrease the mechanical properties, and the appearance of the coated product will be poor, so it is not good .

On the contrary, when the content of the antioxidant is less than the above range, the antioxidant effect cannot be fully exhibited, and therefore it is not preferable.

On the other hand, as described above, the polyamide acid solution can be produced by the polymerization reaction of more than one dianhydride monomer and more than one diamine monomer.

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

The above-mentioned aromatic tetracarboxylic dianhydride may 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 sulfide-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-phenylene dianhydride 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-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,4'-(2,2-hexafluoroisopropylidene)diphthalic dianhydride, etc. These etc. can be used individually or in combination of 2 or more types as desired.

They can be used alone or in combination of two or more according to expectations, but in the present invention, the dianhydride monomer that can be preferably used can be selected from pyromellitic dianhydride (PMDA, pyromellitic dianhydride) and 3 ,3',4,4'-Biphenyltetracarboxylic dianhydrid (BPDA, tetracarboxylic dianhydrid) is composed of more than one species.

The diamine monomers that can be used to prepare the polyamide acid solution of the present invention can be classified and 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 relatively strong structure as a diamine with a benzene nucleus in the structure; 2) Such as 4,4'-diaminodiphenyl ether (or oxydiphenylamine, ODA), 3,4'-diaminodiphenyl ether and other diaminodiphenyl ethers, 4,4'-diamine Diphenylmethane (or methylene diphenylamine, MDA), 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-di Aminodiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-Dicarboxy-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, bis(4- Aminophenyl) thioether, 4,4'-diaminobenzaniline, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine (or o-tolidine), 2 ,2'-dimethylbenzidine (or m-tolidine), 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-diaminodiphenylamine 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 sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diamino Phenyl chloride, 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 sulfene, 3,4'-diaminodiphenyl sulfene, 4,4'-diaminodiphenyl sulfene, etc. have 2 benzenes in the 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)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminophenyl)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 with 3 benzene nuclei in the structure; 4) Such as 3,3'-bis(3-aminophenoxy)biphenyl, 3,3'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-amino) 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]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[3-( 3-aminophenoxy)phenyl] ash, bis[3-(4-aminophenoxy)phenyl] ash, bis[4-(3-aminophenoxy)phenyl] ash, double [4-(4-Aminophenoxy)phenyl] sulfide, 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 4 benzene nuclei in the structure.

These can be used singly or in combination of two or more as desired, but in the present invention, the diamine monomer that can be preferably used can be selected from 4,4'-diaminodiphenyl ether (or oxygen Diphenylamine (ODA) and 4,4'-methylenediphenylamine (MDA) are composed of more than one species.

NS 2 Embodiment: Preparation method of polyimide varnish

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

In the present invention, the preparation of the polyamide acid solution can be exemplified by the following methods: (1) A method in which the entire amount of the diamine monomer is put into the solvent, and thereafter the dianhydride monomer is added so as to be substantially equal to the diamine monomer to polymerize; (2) A method in which the entire amount of the dianhydride monomer is put into the solvent, and then the diamine monomer is added and polymerized in such a way that it becomes substantially equal to the dianhydride monomer; (3) After putting some of the components in the diamine monomer into the solvent, mix some of the components in the dianhydride monomer at a ratio of about 80 mol% to 120 mol% with respect to the reaction components, and then add The remaining diamine monomer components, and the remaining dianhydride monomer components are continuously added here, so that the diamine monomer and the dianhydride monomer are substantially equal-molar for polymerization; (4) After putting the dianhydride monomer into the solvent, mix a part of the diamine compound at a ratio of 90 mol% to 110 mol% relative to the reaction components, and then add other dianhydride monomer components , And continue to add the remaining diamine monomer components to make the diamine monomer and the dianhydride monomer essentially become equal moles for polymerization; (5) A part of the diamine monomer component and a part of the dianhydride monomer component are reacted in a solvent to form the first composition, and a part of the diamine monomer component and a part of the dianhydride monomer Any one of the components is excessively reacted in another solvent to form the second composition, and then the first composition and the second composition are mixed to complete the polymerization. At this time, when the first composition is formed, two When the amine monomer component is too much, the dianhydride monomer component is excessive in the second composition, and when the dianhydride monomer component is too much 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 the overall diamine monomer component and the dianhydride monomer component used for the reaction thereof are substantially equal-molar and polymerized.

The above-mentioned organic solvent is not particularly limited as long as it is a solvent that can dissolve polyamide acid, but as an example, it may be an aprotic polar solvent (aprotic polar solvent).

As non-limiting examples of the aforementioned aprotic polar solvents, N,N'-dimethylformamide (DMF), N,N'-dimethylacetamide (DMAc) and other amine-based solvents, Phenolic solvents such as p-chlorophenol and o-chlorophenol, N-methyl-pyrrolidone (NMP), gamma-butyrolactone (GBL) and diethylene glycol dimethyl ether (Diglyme), etc., which can be used alone Or use a combination of two or more.

Auxiliary solvents such as xylene, toluene, tetrahydrofuran, acetone, methyl ethyl ketone, methanol, ethanol, water, etc. can also be used to adjust the solubility of polyamide acid depending on the situation.

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 as amine-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-mentioned dianhydride monomer can be appropriately selected from the examples described above. In detail, it can be preferably selected from pyromellitic dianhydride (PMDA, pyromellitic dianhydride) and 3,3',4,4'- More than one kind in the group consisting 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 used selected from 4,4'-diaminodiphenyl ether (or oxydiphenylamine, ODA) and 4, 4'-Methylene dianiline (MDA) is composed of more than one species.

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

In addition, the above-mentioned process (b) can be further mixed with an antioxidant in the polyamide 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 antioxidant included in the amine varnish can minimize the change in the physical properties of the polyimide coating product prepared from the above polyimide varnish.

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

However, the specific combination of silicone additives, alkoxysilane coupling agent, antioxidant, and low-temperature hardener contained in the polyimide varnish and slight content differences will also affect the physical properties of the polyimide coating product. Changes occur, and it is not easy to speculate on the above changes.

NS 3 Implementation mode: preparation method of polyimide coated product and polyimide coated product

The preparation method of the polyimide coated product of the present invention is characterized in that it comprises: (1) The process of applying polyimide varnish to the surface of the conductor; and (2) The process of imidizing the polyimide varnish coated on the surface of the conductor; and Repeat the above process (1) and process (2) 4 to 20 times continuously, The softening resistance temperature of the polyimide coated product is above 500°C.

When the above process (1) and process (2) are repeated once, the coating thickness of the polyimide varnish can 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-mentioned conductor may be 2 m/min to 30 m/min.

The above-mentioned conductors may be copper wires including copper or copper alloys, but conductors including other metal materials such as silver wires or various metal-plated wires such as aluminum-plated wires and tin-plated wires can also be included as conductors.

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

In the preparation method of the present invention, the polyimide coating product can be prepared by the thermal imidization method.

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

The above-mentioned thermal imidization method can heat-treat the polyimide varnish at a variable temperature in the range of 100°C to 750°C to imidize the amide acid groups present in the polyimide varnish. In detail, In other words, heat treatment can be performed at 300°C to 750°C, more specifically, 500°C to 700°C to imidize the amide group present in the polyimide varnish.

The thickness of the polyimide coating product of the present invention prepared according to the above-mentioned preparation method can be in the range of 16 μm to 50 μm, the softening resistance temperature is 500°C or more, the tanδ is 270°C or more, and the insulation breakdown voltage (BDV ) Is above 8 kV/mm.

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

Hereinafter, the function and effect of the invention will be described in more detail through specific embodiments 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 the abbreviations used in the 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 gas injection and 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.

The temperature was raised to 50°C in a nitrogen environment, and heating was continued for 120 minutes to prepare a polyamic acid solution with a viscosity of 10,000 cP at 23°C.

After the temperature of the reactor was set to 50°C, OFS-6011 as an alkoxysilane coupling agent and 5% by weight as an antioxidant were added to the polyamide 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 triethylenediamine as a low-temperature hardening agent, slowly stir for 30 minutes to obtain the total solid content The content of NMP becomes about 25% by weight and the viscosity becomes about 3,000 cP. The molar ratio of the prepared diamine monomer to the dianhydride monomer is 100:100, and 0.01 parts by weight relative to 100 parts by weight of the solid content are included. 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-mentioned 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 of the copper wire is adjusted to 500℃, and the coating, drying and hardening process is repeated 7 times under the state of adjusting the coating speed of the copper wire to 12 m/min to prepare a polyamide with a coating thickness of 35 μm. Wires for amine-coated products.

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

Except that the monomers, additives, and the viscosity of the polyimide varnish in Example 1 were changed as shown in Table 1 below, an electric wire was prepared by the same method as Example 1.

<Comparative Example 9>

The compound of the following chemical formula A with a decomposition temperature of about 377°C of 5 wt% was added instead of the compound of the chemical formula 1-1 in Example 1 as the antioxidant, and it was prepared by the same method as in Example 1, except that electric wire.

<Comparative Example 10>

The compound of the following chemical formula B with a decomposition temperature of about 338°C was added at 5 wt% instead of the compound of the chemical formula 1-1 in Example 1 as the antioxidant, and it was prepared by the same method as in Example 1, except that electric wire.

[Table 1]

<Experimental example 1: Evaluation of appearance defects>

The appearance of the polyimide-coated products of the wires prepared in Examples 1 to 13 and Comparative Examples 1 to 16 was visually observed to determine whether they were defective or not. The results are shown in Table 2 below.

For example, when it is a good-quality coated product, it is expressed as "○", and when pinholes or polyimide resin carbonization and other appearance defects are found, it is expressed as "×".

<Experimental Example 2: Evaluation of Thermal Shock Resistance>

The polyimide-coated products of the electric wires prepared in Example 1 to Example 13, and Comparative Example 1 to Comparative Example 16 were evaluated for thermal shock. Thermal shock resistance is an index indicating whether the wire can withstand exposure to temperature in a state where the wire is expanded, or when it is wound around a mandrel or bent.

Specifically, in order to evaluate the thermal shock resistance, the polyimide-coated products of the wires prepared in Example 1 to Example 13, and Comparative Example 1 to Comparative Example 16 were heated for 30 minutes at a temperature of 200°C. After taking out the oven, 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. The results are shown in Table 2 below.

[Table 2]

According to the results in Table 2, it can be seen that the comparative example using silicone additives, alkoxysilane coupling agent, or low-temperature hardening agent in a manner outside the scope of the present invention cannot achieve uniform coating of polyimide coating products. Or carbonization occurs locally, and thermal shock resistance is weak.

<Experimental example 3: Evaluation of physical properties>

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

(1) tanδ value

Use DSE's TD300 tan δ tester (Tan Delta Tester) to measure the tan δ value of polyimide coated products.

Specifically, the test piece is connected to the bridge with the conductor as one electrode and the graphite coating as the other electrode, so that the temperature of the assembly increases at a fixed rate from the ambient temperature to a temperature that provides a clearly defined curve. The temperature is determined by the detector in contact with the sample, and the result is plotted as a linear axis with respect to temperature and a logarithmic or linear axis graph with respect to tanδ, and the value of tanδ of the polyimide-coated product is calculated based on the above value.

(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 wires that cross 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 wires are overlapped 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. In this state, the ratio is about 2°C/min. The temperature of the short circuit is measured by increasing the temperature.

(3) Insulation destruction voltage (BDV)

After pretreating the test piece in an oven at 150°C for 4 hours, it was placed in a pressure vessel. After filling the pressure vessel with a refrigerant of 1400 g 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 kept for 10 minutes to cool to room temperature. Connect the two ends of the wire, and increase the test voltage (60 Hz) AC voltage at the nominal frequency between the wire conductors at a constant speed from 0 to determine the BDV.

(4) Pinhole test

In order to confirm whether there are defects in the insulator of the polyimide-coated product of the electric wire, a pinhole test is carried out. Specifically, take a test piece of wire with a length of about 1.5 m and place it in an air-circulating oven (125°C) for 10 minutes, and then cool it at room temperature without any bending or elongation. The cooled wire test piece was immersed in a sodium chloride electrolyte solution containing phenolphthalein alcohol while connected to a circuit with a direct current test voltage, and then taken out, and the number of pinholes was visually confirmed.

<Experimental Example 4: Tensile Test>

In order to confirm the adhesion between the conductor and the coated product, a tensile test was performed on the polyimide coated product of the wire prepared in Example 1 to Example 13, and Comparative Example 1 to Comparative Example 16, and the results Shown in Table 3 below.

Specifically, a straight wire test piece with a freely measurable length of 200 mm to 250 mm is quickly stretched to the breaking point or the length (20%) given in the corresponding standard. After elongation, check whether the test piece has adhesive force loss or cracks at the specified magnification (1 to 6 times). The 2 mm length at the end of the damaged wire should be ignored.

Experiment on 3 test pieces. If the wire appears to be cracked and/or adhesive loss, record this situation.

[table 3]

Referring to Table 3, the polyimide coating products of Example 1 to Example 13 prepared from the polyimide varnish including silicone additives, alkoxysilane coupling agent, low-temperature hardener and antioxidant of the present invention The tanδ is 270℃ or higher, the softening temperature is 500℃ or higher, and the heat resistance is excellent. The insulation breakdown voltage is 8 kV/mm or higher and the insulation is excellent. The tensile test can confirm the difference between the conductor and the coated product. Excellent adhesion.

On the contrary, the following conditions can be confirmed: Comparative Example 1 where silicone additives, alkoxysilane coupling agent, low-temperature curing agent, antioxidant and solid content, viscosity, and maximum temperature of the curing furnace are different from those of the examples. At least one of tanδ, softening resistance temperature, and dielectric breakdown voltage of Comparative Example 16 was lower than that of the Examples, and there were relatively many pinholes confirmed by the pinhole test, that is, defects of the insulator. In addition, it was confirmed that in some comparative examples, cracks were observed on the outer surface of the polyimide-coated product in the tensile test, and the adhesive force between the conductor and the coated product was reduced.

The above has been described with reference to the embodiments of the present invention, but those with common sense in the technical field to which the present invention belongs can make various applications and modifications within the scope of the present invention based on the above content.

without

without

Claims (18)

A polyimide varnish, which is a polyimide varnish for conductor coating, comprises: a polyimide acid solution, which is prepared by polymerizing more than one dianhydride monomer and more than one diamine monomer in an organic solvent Preparation; 0.01 parts by weight to 0.05 parts by weight of silicone additives relative to 100 parts by weight of the solid content of the polyimide varnish; 0.01 parts by weight to 0.05 parts by weight of alkoxysilane coupling agent relative to 100 parts by weight Parts of the solid content of the polyimide varnish; a low-temperature hardener; and an antioxidant, wherein the decomposition temperature of 5 wt% of the antioxidant is 380° C. or more and is prepared from the polyimide varnish The softening resistance temperature of the coated products is above 500℃. The polyimide varnish as described in item 1 of the scope of patent application, wherein the silicone additives include selected from the group consisting of dimethylpolysiloxane and polyether modified polydimethylsiloxane ( Polyether modified polydimethylsiloxane), polymethylalkylsiloxane (Polymethylalkylsiloxane), and silicone compounds including hydroxyl (-OH) and carbon-carbon double bond structure (C=C) are composed of more than one kind. The polyimide varnish according to item 1 of the scope of patent application, wherein the alkoxysilane coupling agent is selected from the group consisting of 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane , 3-Aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3- Phenyl One or more of the group consisting of aminopropyltrimethoxysilane, 2-aminophenyltrimethoxysilane, and 3-aminophenyltrimethoxysilane. The polyimide varnish according to item 1 of the scope of the patent application, wherein the solid content of the polyimine varnish includes 0.1 to 2 parts by weight of the low-temperature hardener relative to 100 parts by weight of the solid content of the polyimide varnish . The polyimide varnish according to the first item of the patent application, wherein the low-temperature hardener includes one selected from the group consisting of β-picoline, isoquinoline, triethylenediamine and pyridine above. The polyimide varnish according to item 5 of the scope of the patent application, wherein the low-temperature hardener includes one or more selected from the group consisting of β-picoline, isoquinoline and pyridine and triethylene diethylene amine. The polyimide varnish as described in item 1 of the scope of the patent application, wherein the dianhydride monomer is selected from the group consisting of pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarboxylic dianhydride More than one kind of ethnic group. The polyimide varnish according to item 1 of the scope of patent application, wherein the diamine monomer includes selected from 4,4'-diaminodiphenyl ether (or oxydiphenylamine) and 4,4'- More than one species in the group consisting of methylene diphenylamine. The polyimide varnish according to item 1 of the scope of patent application, wherein the solid content of the polyimide varnish includes 0.1 to 2 parts by weight of the antioxidant relative to 100 parts by weight of the polyimide varnish. A preparation method of polyimide varnish, which is a method for preparing polyimide varnish as described in item 1 of the scope of patent application, comprising: (a) polymerizing more than one dianhydride monomer and one type in an organic solvent The process of preparing the polyamide acid solution from the above diamine monomer; and (b) The process of mixing silicone additives, alkoxysilane coupling agent and low temperature hardening agent in the polyamide acid solution. The method for preparing polyimide varnish as described in item 10 of the scope of patent application, wherein the process (a) is performed at a temperature of 30°C to 80°C, and the viscosity of the polyimide acid solution at a temperature of 23°C is 500 cP To the range of 9,000 cP, process (b) is performed at a temperature of 40°C to 90°C. A preparation method of a polyimide coating product includes: (1) a process of coating the polyimide varnish as described in item 1 of the scope of the patent application on the surface of a conductor; and (2) applying the coating to the surface of the conductor; The process of preparing the polyimide coating product by the polyimide varnish on the surface of the conductor, and the process (1) and the process (2) are continuously repeated 4 to 20 times, the The softening resistance temperature of polyimide coated products is above 500°C. The method for preparing polyimide coated products as described in item 12 of the scope of patent application, wherein each time process (1) and 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., and the coating speed of the conductor is 2 m/min to 30 m/min. The method for preparing a polyimide-coated product as described in item 12 of the scope of the patent application, wherein the conductor is an electric wire having a diameter of 0.1 mm to 5 mm. A polyimide coated product is prepared by the preparation method of the polyimide coated product as described in item 12 of the scope of patent application. Such as the polyimide coating product described in item 15 of the scope of patent application, which The thickness is in the range of 16 μm to 50 μm, the tan δ is 270° C. or more, and the insulation breakdown voltage is 8 kV/mm or more. An electric wire comprising a polyimide coating product prepared by coating the polyimide varnish as described in item 1 of the scope of patent application on the surface of the electric wire for imidization. An electronic device, which includes the wire as described in item 17 of the scope of the patent application.