JP2013173820A - Novel polyimide and printing composition including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel thermosetting polyimide which allows high-speed printing in screen printing, and has excellent adhesiveness, bendability and a low warping property and good storage stability, as well as characteristics such as heat resistance, electric characteristics, mechanical characteristics and incombustibility, and to provide a printing composition including the same, and a method for forming an insulating film, using the composition.SOLUTION: A thermosetting polyimide excellent for use in printing has a repeating unit of a specific structure including a triple bond. A printing ink composition includes the polyimide and an organic solvent for dissolving the polyimide. A method for forming an insulating film includes: applying the composition onto a base layer followed by drying to thereby form an insulating film composed of a polyimide film.

Description

  The present invention relates to a novel polyimide, a printing composition containing the same, and a method for forming an insulating film using the same.

  In recent years, in the field of electronic parts and solar cell materials, a protective film (coverlay film) for protecting wiring (copper foil pattern or the like) is often provided on the outer surface. In addition, polyimide resin, polyamideimide resin, polyurethane resin, epoxy resin, etc. are used as insulating protective films with excellent heat resistance, electrical properties, and moisture resistance in order to cope with high speed, pattern definition, flexibility, and flame resistance. It has been. These resins have a rigid resin structure, and when used as a thin film substrate, the cured substrate is greatly warped, and the cured film lacks flexibility and has poor flexibility.

  Patent Documents 1 and 2 disclose a composition made of siloxane-modified polyimide derived from diaminopolysiloxane. Siloxane-modified polyimide is excellent in heat resistance and electrical insulation and, in addition, has low warpage due to its low elasticity. However, due to the polysiloxane component, the adhesion of the cured film surface is not sufficient, and excellent properties such as electrical properties, mechanical properties and heat resistance inherently possessed by the polyimide resin are impaired, and dielectric strength, nonflammability properties There was a problem such as lowering.

  In addition to the method for improving the warp due to the low elasticity, a method for improving the warp with the substrate by lowering the thermal expansion coefficient is known. However, it is difficult to design a composition while maintaining a balance of physical properties, and the cured resin film formed by such a method is uniform in appearance, particularly unevenness in appearance and mechanical properties due to differences in reactivity due to molecular weight distribution during curing. The above variation was cited as a problem. (Non-patent documents 1, 2, 3)

JP 7-304950 A JP-A-8-333455

NASA heat-resistant composite material (Techno system, p4-13, p361-373) Polymer ABC Handbook (NTS, p799, p962) Recent progress in polyimide 2001 (Textile Industry Technology Promotion Association, p. 29)

  The present invention has been made in view of such points, and can be printed at high speed in screen printing, has heat resistance, electrical properties, mechanical properties, nonflammability, and the like, and has adhesiveness and flexibility, It is an object of the present invention to provide a novel thermosetting polyimide having excellent low warpage and good storage stability, a printing composition containing the same, and a method for forming an insulating film using the same.

  As a result of earnest research, the inventors of the present application have created a novel polyimide having a triple bond in a repeating unit, and when this polyimide is used as an ink for screen printing, high-speed printing is possible in screen printing, and heat resistance It has been found that an insulating film having characteristics such as electrical characteristics, mechanical characteristics and nonflammability, excellent adhesion, flexibility, low warpage, and good storage stability can be formed. Completed the invention.

  That is, the present invention provides the following general formula [I]

(In the formula, AR ¹ is an arbitrary tetravalent organic group, AR ² is an arbitrary divalent organic group, and at least one of AR ¹ and AR ² has a triple bond)
The polyimide which has a repeating unit represented by these is provided.

  Moreover, this invention provides the ink composition for printing containing the polyimide of the said invention and the organic solvent which melt | dissolves this polyimide. Furthermore, this invention provides the formation method of an insulating film including apply | coating the composition of the said invention on the base layer, and drying and forming the insulating film which consists of a polyimide film.

  According to the present invention, a novel polyimide having a triple bond in a repeating unit is provided for the first time. When this polyimide is used as an ink for screen printing, high-speed printing is possible in screen printing, which has properties such as heat resistance, electrical properties, mechanical properties, and nonflammability, adhesion, flexibility, and low warpage. It is possible to form an insulating film having excellent properties and storage stability.

The infrared absorption spectrum (FT-IR) of the polyimide of this invention synthesize | combined in the following comparative example 1 is shown.

As described above, the polyimide of the present invention is represented by the above general formula [I]. In general formula [I], AR ¹ is an arbitrary tetravalent organic group, AR ² is an arbitrary divalent organic group, and at least one of AR ¹ and AR ² has a triple bond. As AR ¹ , the following general formula [II]:

[II]

[II]

(In the formula, E represents a single bond, —C≡C—, —O—, —C (CH ₃ ) ₂ — or —C (CF ₃ ) ₂ —).
In particular, those in which E is —C≡C— are preferred. Preferred examples of tetracarboxylic dianhydrides having a structure represented by the general formula [II] include 4,4- (1,2-ethynyl) bisphthalic anhydride represented by the following formula [VI]. it can.

[VI]

[VI]

In addition, AR ² in the general formula [I] is represented by the following general formula [III]:

[III]
（式中、Ｗは、-C(CH₃)₂-又は-C(CF₃)₂-を表す）
で表されるもの、又はAR²が下記一般式[IV]：

[III]
(Wherein represents -C (CH ₃ ) ₂ -or -C (CF ₃ ) _2- )
Or AR ² is represented by the following general formula [IV]:

[IV]

[IV]

(Wherein X is —C≡C—, —C (═O) —, —SO ₂ —, —O—, —S—, — (CH ₂ ) _a — (A is an integer of 1 to 5) Selected from the group consisting of: -NHCO-, -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -C (= O) O- and a single bond, and R ₁ and R ₂ are Independently selected from hydrogen, hydroxyl group, carboxyl group, alkyl group having 1 to 4 carbon atoms, phenyl group, F, CL and BR (however, P1 and P2 each independently represent an integer of 1 to 4)
Or AR ² is represented by the following general formula [V]:

[V]

[V]

Wherein Y and Z are independently of each other —C (═O) —, —SO ₂ —, —O—, —S—, — (CH ₂ ) _a — (A represents an integer of 1 to 5 ), -NHCO-, -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -C (= O) O- and a single bond, R ₃ , R ₄ and R ₅ Are independently selected from hydrogen, hydroxyl group, carboxyl group, alkyl group having 1 to 4 carbon atoms, phenyl group, F, CL and BR (provided that at least one of R ₃ , R ₄ and R ₅ is A group having 1 to 4 carbon atoms), and P3, P4 and P5 each independently represent an integer of 1 to 4))
The thing represented by these is preferable.

  Preferred examples of the diamine having the structure represented by the above formula [III] include 2,2-bis [4- (4-aminophenoxy) phenyl] propane and 2,2-bis [4- (4-aminophenoxy) phenyl. ] Hexafluoropropane, α, α-bis [4- (4-aminophenoxy) phenyl] -1,3-diisopropylbenzene, α, α-bis [4- (4-aminophenoxy) phenyl] -1,4- Mention may be made of diisopropylbenzene.

Preferred examples of the diamine having the structure represented by the above formula [IV] include 3,7-diamino-dimethyldibenzothiophene 5,5-dioxide, bis (3-carboxy-4-aminophenyl) methylene, 2,2-bis ( 3-hydroxy-4-aminophenyl) propane, 2,2-bis (4-aminophenyl) propane, 2,2-bis (3-methyl-4-aminophenyl) propane, 2,2-bis (4-amino) Phenyl) hexafluoropropane, 2,2-bis (3-amino-4-methylphenyl) hexafluoropropane, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, 5,5'-methylenebis (2-aminobenzoic acid) and 3,3′-diamino-4,4′-dihydroxydiphenylsulfone can be mentioned.

  Preferred examples of the diamine having the structure represented by the above formula [V] include α, α-bis (4-aminophenyl) -1,3-diisopropylbenzene, α, α-bis (4-aminophenyl) -1, 3-dihexafluoroisopropylidenebenzene, α, α-bis (4-aminophenyl) -1,4-diisopropylbenzene, α, α-bis (4-aminophenyl) -1,4-dihexafluoroisopropylidenebenzene Can be mentioned.

  As the tetracarboxylic dianhydride and diamine constituting the polyimide used in the present invention, usually, together with the tetracarboxylic dianhydride and / or diamine having the ethynyl group, heat resistance, electrical characteristics, film physical properties, Other tetracarboxylic dianhydrides and / or diamines can be used in combination in order to impart various functions such as adhesion.

  Examples of such tetracarboxylic dianhydrides include pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, and bis (3,4-dicarboxyphenyl) ether. Dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfonetetracarboxylic dianhydride, bicyclo [2.2.2] octane -7-ene-2,3,5,6-tetracarboxylic dianhydride and the like, and bis (3,4-dicarboxyphenyl) ether dianhydride, Preferably, ', 4,4'-biphenylsulfonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 3,4'-oxydiphthalic anhydride, 3,3'-oxydiphthalic anhydride is used. Can do. These tetracarboxylic dianhydrides may be used alone or in combination of two or more.

  Examples of the diamine include m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 4,4′-diamino-2,2′-dimethyl-1,1′-biphenyl, 4,4′-diamino-2. , 2′-ditrifluoromethyl-1,1′-biphenyl, 4,4′-diamino-3,3′-ditrifluoromethyl-1,1′-biphenyl, 4,4′-diamino-3,3′- Dihydroxy-1,1′-biphenyl, 4,4′-diamino-3,3′-dimethyl-1,1′-biphenyl, 9,9′-bis (3-methyl-4-aminophenyl) fluorene, 3, 5-diaminobenzoic acid, 2,6-diaminopyridine, 4,4 ′-(hexafluoroisopropylidene) dianiline, 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropro 2,2-bis (3-amino-4-methylphenyl) hexafluoropropane, 4,4 ′-(9-fluorenylidene) dianiline, 1,3-bis (3-aminophenoxy) benzene, 1,3- Bis (3-hydroxy-4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,2-bis (3-hydroxy-4) -Aminophenyl) benzene, 2,2-bis (3-methyl-4-aminophenyl) benzene and the like. These diamines are used alone or in combination of two or more.

  The polyimide used in the present invention is obtained by combining the above-described tetracarboxylic dianhydride and / or diamine having an ethynyl group and the above-described tetracarboxylic dianhydride and / or diamine other than these. The ratio of the component which has an ethynyl group among the tetracarboxylic dianhydride component and diamine component which comprise a polyimide is 10-80 mol% normally, Preferably, it is 20-60 mol%. When the proportion of the component having an ethynyl group is within this range, excellent cured film characteristics can be obtained.

  Moreover, a reactive group can be introduced into the terminal portion of the polyimide in order to improve chemical resistance. For example, a slightly larger amount of tetracarboxylic acid is added and synthesized so that the end of polyimide becomes an acid anhydride, and then an amine compound typified by 3-ethynylaniline or 4-ethynylaniline is added. An acetylene group can be introduced into. It is also possible to add a slight amount of a diamine compound so as to be an amine terminal, and then add an acid anhydride typified by maleic anhydride, ethynyl phthalic anhydride or phenyl ethynyl phthalic anhydride. Reactive groups can be introduced. These end groups react with each other by heating at 150 ° C. or higher, and the polymer main chain is crosslinked.

  The polyimide contained in the polyimide resin composition of the present invention can be produced by a known synthesis method in which tetracarboxylic dianhydride and diamine are dissolved in an organic solvent and directly imidized in the presence of an acid catalyst. Further, it can also be produced by dissolving and reacting tetracarboxylic dianhydride and diamine in an organic solvent, followed by imidization by adding at least one of tetracarboxylic dianhydride and diamine. The mixing ratio of tetracarboxylic dianhydride and diamine is preferably 0.9 to 1.1 mol% of the total amount of diamine with respect to 1 mol% of the total amount of acid dianhydride. Here, as the acid catalyst, chemical imidation using a catalyst such as acetic anhydride / triethylamine or valerolactone / pyridine can be suitably used. The reaction temperature is preferably 80 to 250 ° C., and the reaction time can be appropriately selected depending on the scale of the batch, the reaction conditions employed, and the like. Moreover, the block copolymerization polyimide obtained by performing imidation reaction in 2 steps or more and reacting different tetracarboxylic dianhydride and / or diamine in each step can be preferably used. In addition, the manufacturing method itself of solvent-soluble block copolymerization polyimide itself is well-known as described, for example in patent document 10, The polyimide used suitably for this invention is the above-mentioned tetracarboxylic dianhydride and / or. It can be synthesized by a known method using diamine.

  The number average molecular weight of the polyimide resin thus obtained is preferably 2000 to 60000, and more preferably 4000 to 40000. Here, the number average molecular weight is a polystyrene equivalent value based on a calibration curve prepared using standard polystyrene by a gel permeation chromatography (GPC) apparatus.

  The organic solvent contained in the printing ink composition of the present invention is not particularly limited as long as the polyimide resin and the filler are added as long as they dissolve the filler. Since it is printed by screen printing and dried at a low temperature, the boiling point of the organic solvent under atmospheric pressure is 80 ° C. or higher and lower than 300 ° C., more preferably 120 ° C. or higher and lower than 250 ° C. If it is lower than 130 ° C., drying may be too fast in screen printing, and printing may not be successful. When it is 250 ° C. or higher, drying at a low temperature may be slow. Specifically, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl Ethers such as ethyl ether, dipropylene glycol dimethyl ether, diethylene glycol dibutyl ether, dibenzyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propyl acetate Acetate, propylene glycol diacetate, butyl acetate, isobutyl acetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, benzyl acetate, butyl carbitol acetate, etc., methyl lactate, ethyl lactate, lactic acid Esters such as butyl, methyl benzoate and ethyl benzoate, glymes such as triglyme and tetraglyme, ketones such as acetylacetone, methylpropylketone, methylbutylketone, methylisobutylketone, cyclopentanone and 2-heptanone, butyl Alcohols such as alcohol, isobutyl alcohol, pentanol, 4-methyl-2-pentanol, 3-methyl-2-butanol, 3-methyl-3-methoxybutanol, diacetone alcohol, Aromatic hydrocarbons such as xylene, and other, .gamma.-butyrolactone, N- methylpyrrolidone, N, N- dimethylformamide, N, N- dimethylacetamide, and dimethyl sulfoxide.

  The proportion of the solid content of the polyimide resin in the composition of the present invention is preferably 15 to 50% by weight, and more preferably 25 to 40% by weight. If it is less than 15% by weight, the film thickness that can be generated by one printing and coating tends to be thin, and multiple printings and coatings tend to be required. If it exceeds 50% by weight, the viscosity of the resin composition is too high There is a tendency to end up.

  The ink composition of the present invention can impart thixotropic properties. The thixotropic property is often possessed by the polyimide itself of the present invention, but when the polyimide itself does not have thixotropic property, it can be imparted by adding an inorganic filler. It is also an effective means to contain an inorganic filler in the composition. Examples of the inorganic filler for imparting thixotropy include inorganic fillers composed of at least one of silica, alumina, titania, silver, and copper. Specific examples include amorphous silica of 0.01 to 0.03 μm and / or spherical silica, alumina, or titania having a particle size of 0.1 to 0.3 μm. Moreover, it is more preferable to use an inorganic filler surface-treated with a trimethylsilylating agent or the like for the purpose of enhancing storage stability. The content of the inorganic filler in the composition is usually 0 to 50% by weight, preferably 2 to 30% by weight. When the content of the inorganic filler is in this range, appropriate thixotropic properties are imparted.

  Moreover, if there is no influence on a product, additives, such as a coloring agent, an antifoamer, a leveling agent, an adhesiveness imparting agent, can be added to the polyimide resin composition of this invention as needed. Examples of the colorant include phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, carbon black, naphthalene black and the like. The antifoaming agent is used to eliminate bubbles generated during printing, coating, and curing, and an acrylic or silicone surfactant is appropriately used. Specifically, BYK-A501 of BYK Chemi, DC-1400 of Dow Corning, SAG-30, FZ-328, FZ-2191, FZ-5609, etc. of Nippon Unicar Co., Ltd. are listed as silicone-based defoamers. It is done. The leveling agent is used to lose unevenness on the surface of the film that occurs during printing and coating. Specifically, it is preferable to contain about 100 ppm to about 2% by weight of a surfactant component, and an acrylic or silicone leveling agent can suppress foaming and make the coating film smooth. Preferably, it is non-ionic without ionic impurities. Examples of suitable surfactants include FC-430 from 3M, BYK-051 from BYK Chemi, Y-5187, A-1310, and SS-2801 to 2805 from Nippon Unicar. Examples of the adhesion-imparting agent include imidazole compounds, thiazole compounds, triazole compounds, organoaluminum compounds, organotitanium compounds, and silane coupling agents. These additives are preferably blended in an amount of 10 parts by weight or less with respect to 100 parts by weight of the polyimide resin component. When the compounding amount of the additive exceeds 10 parts by weight, the physical properties of the obtained coating film tend to be lowered and the problem of contamination by volatile components also occurs. For this reason, it is most preferable not to add said additive.

  Moreover, you may add a hardening | curing agent to the composition of this invention. Although it does not specifically limit as a hardening | curing agent, Phenolic resins, such as a phenol novolak type phenol resin, a cresol novolak type phenol resin, a naphthalene type phenol resin, amino resins, urea resins, melamine resins, dicyandiamide, di Examples include hydrazine compounds, imidazole compounds, Lewis acids, Bronsted acid salts, polymercaptan compounds, isocyanates and blocked isocyanate compounds, and the like.

  The said hardening | curing agent can be used 1 type or in combination of 2 or more types, It is preferable to use within the range of 1 weight part-100 weight part with respect to 100 weight part of all the polyimide resins.

  Moreover, you may use a hardening accelerator with the said hardening | curing agent. The curing accelerator is not particularly limited. For example, phosphine compounds such as triphenylphosphine; amine compounds such as tertiary amine, trimethanolamine, triethanolamine, tetraethanolamine; 1,8-diaza- Borate compounds such as bicyclo [5,4,0] -7-undecenium tetraphenylborate, imidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole Imidazoles such as 1-benzyl-2-methylimidazole, 2-isopropylimidazole, 2,4-dimethylimidazole, 2-phenyl-4-methylimidazole; 2-methylimidazoline, 2-ethylimidazoline, 2-isopropylimidazoline, 2-fe Imidazolines such as loumidazoline, 2-undecylimidazoline, 2,4-dimethylimidazoline, 2-phenyl-4-methylimidazoline; 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]- Ethyl-s-triazine, 2,4-diamino-6- [2'-undecylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-ethyl-4' Examples include azine-based imidazoles such as -methylimidazolyl- (1 ')]-ethyl-s-triazine. When the imide resin contains an amino group, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 2,4-diamino-6- [2 can be used because the circuit embedding property can be improved. It is preferable to use imidazoles such as '-undecylimidazolyl- (1')]-ethyl-s-triazine.

  The said hardening accelerator can be used combining 1 type (s) or 2 or more types, It is used within the range of 0.01 weight part-10 weight part with respect to 100 weight part of all thermosetting resin group compositions. Is preferred.

  The polyimide resin composition of the present invention has a viscosity at 25 ° C. of preferably 100 to 50000 mPa · s, and more preferably 500 mPa · s to 40000 mPa · s. If this is less than 500 mPa · s, sagging or the like is likely to occur, and a sufficient film thickness and resolution may not be obtained. If it exceeds 40000 mPa · s, the transferability and the printing workability tend to be inferior. In addition, the viscosity numerical value in this invention shall be represented with the apparent viscosity obtained on the conditions of the shear rate 333 (1 / s) using a rheometer.

  This viscosity value is an important factor not only for the shape retention immediately after coating, but also for the fluidity that easily deforms and flows with a squeegee during screen printing. In screen printing, when the viscosity is high, rolling of the resin composition is deteriorated, so that coating with a scraper becomes insufficient, and coating unevenness or scratches tend to occur.

  In addition, if the ink does not have shape retention ability to maintain the printed shape immediately after being applied to the desired pattern shape by screen printing or the like, bleeding and sagging occur in the outer periphery of the pattern, so a thick film with high resolution can be obtained. Can't get. If the viscosity is simply increased, sagging and the like can be suppressed, but a problem of plate separation and a problem of flatness of the coating film occur in screen printing. Therefore, the thixotropy coefficient is important in order to prevent bleeding and sagging. Usually, rheometer measurement can be quantified and evaluated from the area obtained by hysteresis curve (measurement of viscosity rotation speed dependence), but it is a method of evaluating with a TI value using a more general viscometer. Is the simplest. In the present invention, the thixotropic coefficient is expressed as the apparent viscosity of the resin composition at a shear rate of 33 (1 / s) and 333 (1 / s), and the ratio η33 / η333 between η33 and η333.

  Therefore, the polyimide resin composition of the present invention preferably has a thixotropic coefficient (η33 / η333) at 25 ° C. in the range of 1.5 to 10.0, and more preferably 1.8 to 8. This is because if the thixotropy coefficient is 1.5 or more, sufficient resolution can be easily obtained by screen printing, while if it is 8.0 or less, workability during printing is improved.

The polyimide resin composition of the present invention preferably has high wettability with silicon substrates, ceramic substrates, glass substrates, glass epoxy substrates, metal substrates typified by Ni, Cu, and Al substrates, and PI coating substrates. That is, the contact angle at room temperature is preferably 20 to 90 ° in any of silicon, SiO ₂ film, polyimide resin, ceramic, and metal surface. If it is 90 ° or less, a uniform coating film can be obtained without any flaming, cissing or pinhole. If it exceeds 90 °, the resin paste will bounce on the substrate, and pinholes, patterning defects, etc. will occur. On the other hand, if it is 20 ° or less, sagging occurs during leveling after coating, and the pattern accuracy tends to decrease, such being undesirable. The contact angle is such that when a droplet of the heat-resistant resin paste is dropped on various substrates, a tangent is drawn from the contact point between the droplet and the substrate, and the angle between the tangent and the substrate is defined as the contact angle. The “room temperature” mainly refers to a temperature around 25 ° C. In addition, the contact angle of a composition can be adjusted with a polyimide resin composition, a solvent, surfactant, an antifoamer, and a leveling agent.

  By applying and drying the polyimide composition on the base layer in the solar cell, an insulating film in the solar cell can be formed. As a method for applying the polyimide resin composition of the present invention, a screen printing method, a dispensing method, and an ink jet method are preferable. Particularly, the screen printing method is optimal in that a large area can be applied in a short time. With a single application, it is possible to stably form a film having a thickness after drying of 1 μm or more, preferably 2 μm or more. Considering the insulation reliability, it is desirable to obtain a thickness of at least 5 μm by one application. Therefore, in the screen printing method, a mesh plate having a wire diameter of 50 μm or less and 420 mesh or more and a resin having a rubber hardness of 70 to 90 degrees are used. It is desirable to screen print using a squeegee. The specifications of the screen plate such as the mesh diameter and the number of meshes can be appropriately selected depending on the desired film thickness and pattern size. In addition, fine lines can be drawn by the dispensing method, and it is possible to achieve that the line width of the wet coating film is within + 20% even when left at room temperature for one day as compared with the line width immediately after application. . Furthermore, it is possible to draw fine lines by the ink jet method, and it is possible to achieve that the line width of the wet coating film is within + 100% even when left at room temperature for one day as compared with the line width immediately after coating. .

  The polyimide resin composition can obtain an insulating film and a protective film having excellent electrical characteristics, heat resistance, and chemical resistance by performing leveling, vacuum drying, and final curing process after printing. The leveling is preferably performed for 10 minutes or more. The vacuum drying is preferably performed because the finish of the coating film is improved, but may not always be necessary when a leveling agent or an antifoaming agent is added. The final curing temperature and time can be appropriately selected depending on the solvent of the polyimide resin composition and the applied film thickness.

The present invention will be described in more detail based on examples. The present invention is not limited to the following examples. In the examples, each physical property value was measured by the following method.

1. Comparative synthesis example 1 of polyimide
A Dean's Stark trap was attached to a 2 liter separable three-necked flask equipped with a stainless steel vertical stirrer. Oxydiphthalic anhydride (ODPA) 337.51 g (1088 mmol), 4,4 ′-(1,3-phenylenediisopropylidene) bisaniline (Bisaniline-M) 70.28 g (408 mmol), 2,2-bis [ 4- (4-aminophenoxy) phenyl] propane (BAPP) 73.89 g (640 mmol), γ-valerolactone 10.89 g, pyridine 17.21 g, methyl benzoate (BAME) 966.3 g, tetraglyme 414.3 g Toluene 50g was charged. After stirring for 30 minutes at 180 rpm in a nitrogen atmosphere at room temperature, the mixture was heated to 180 ° C. and stirred for 5 hours. During the reaction, toluene-water azeotrope was removed. By removing the reflux from the system, a 28% concentration polyimide solution was obtained.

Example 1
The same apparatus as in Comparative Example 1 was used. 4,4- (1,2-ethynyl) bisphthalic anhydride (EBPA) 12.73 g (40 mmol), Bisanline-M 9.29 g (20 mmol), BAPP 8.21 g (20 mmol), γ-valerolactone 4 g, 0.63 g of pyridine, 77.7 g of γ-butyrolactone (GBL), 77.7 g of methyl benzoate, and 28 g of toluene were charged. After stirring for 30 minutes at 180 rpm in a nitrogen atmosphere at room temperature, the mixture was heated to 180 ° C. and stirred for 3 hours. During the reaction, toluene-water azeotrope was removed. By removing the reflux from the system, a 28% concentration polyimide solution was obtained.

Example 2
The same apparatus as in Comparative Example 1 was used. (ODPA) 337.51 g (1088 mmol), 4,4 ′-(1,3-phenylenediisopropylidene) bisaniline (Bisaniline-M) 150.31 g (408 mmol), 2,2-bis [4- (4 -Aminophenoxy) phenyl] propane (BAPP) 279.15 g (680 mmol), γ-valerolactone 10.89 g, pyridine 17.21 g, methyl benzoate (BAME) 966.3 g, tetraglyme 414.3 g, toluene 50 g. Prepared. After stirring for 30 minutes at 180 rpm in a nitrogen atmosphere at room temperature, the mixture was heated to 180 ° C. and stirred for 5 hours. After the reaction for 5 hours, 14.06 g (15.4 mmol) of 4-phenylethynylphthalic anhydride was charged and reacted at 180 ° C. for 2 hours to complete the reaction. By removing the reflux from the system, a 28% concentration polyimide solution was obtained.

3. Film Formation A film was formed on the substrate using the above composition. It was a substrate polyimide Kapton film (25 μm), and each composition was applied by screen printing. Specific application conditions were polyester mesh # 420, and printing was performed at a squeegee hardness of 80 degrees, an attack angle of 70 degrees, a clearance of 2.5 mm, an actual printing pressure of 0.15 MPa, and a printing speed of 80 mm / sec. Next, the coating film was dried to form a polyimide film. The drying conditions were leveling for 10 minutes, releasing the polyimide film pre-baked at 120 ° C. for 10 minutes from the Kapton film, raising the temperature of the release film again in a drying furnace, and heating at 250 ° C. for 60 minutes or 300 ° C. 60 minutes was performed under nitrogen atmosphere. The film thickness after drying was 15 μm.

4). Evaluation The properties of the above-described polyimide, composition or formed film were evaluated. Evaluation was performed as follows.

(A) Molecular weight: The number average molecular weight Mn of the polyimide resin was measured by gel permeation chromatography GPC (HLC-8220 GPC, manufactured by Tosoh Corporation). The column used was TSKgel GMH _HR- H manufactured by Tosoh Corporation, and the carrier solvent used was a solution of LiBr dissolved in DMF at a concentration of 0.01M. The molecular weight is a converted value calculated using standard polystyrene (TSK standard polystyrene).

(B) Thermal characteristics: The thermal decomposition starting temperature of the polyimide resin was measured with a DuPont 951 thermogravimetric apparatus.

(C) Mechanical properties: The mechanical properties of the polyimide resin are as follows: the drying condition is leveling for 10 minutes, the polyimide film prebaked at 120 ° C. for 10 minutes is released from the Kapton film, and the release film is again dried in a drying furnace. The temperature was raised, and the reaction was performed at 250 ° C. for 60 minutes or 300 ° C. for 60 minutes in a nitrogen atmosphere. About the polyimide resin film, breaking strength, elongation rate, and initial elastic modulus were measured with a universal tensile tester (Orientec Co., Ltd., Tensilon UTM-11-20).

(D) Viscosity and thixotropy coefficient were measured using a rheometer RS300 manufactured by Thermo Haake. Specifically, it was performed as follows. After adjusting the plate (fixed part) to 25 ± 0.1 ° C., a sample amount of 0.5 to 1.0 g is placed. The cone (movable part) is moved to a predetermined position, and the resin solution is held between the plate and the cone until the temperature reaches 25 ± 0.1 ° C. Start rotating the cone, gradually increase the rotation speed so that the shear rate becomes 33 (1 / s) in 10 seconds, hold the speed, and read the viscosity after 1 minute. Next, the rotational speed is increased so that the shear rate reaches 333 (1 / s) in 10 seconds, and the viscosity at 333 (1 / s) is read. A value obtained by dividing the numerical value at 33 (1 / s) thus obtained by the numerical value at 333 (1 / s) was defined as a thixotropic coefficient.

(F) Printability was printed using a printing machine LS-34TVA manufactured by Neurong Seimitsu Kogyo Co., Ltd., a screen plate polyester mesh # 420-27 manufactured by NBC Co., Ltd., and L-Screen. Printing was performed on the entire surface of the 6-inch silicon wafer, and the number of cracks and repels was visually examined.

(G) For continuous printability, printing is performed using the apparatus used in (f), and printing is stopped for 20 minutes after printing three times. Printing was performed again, and the product that was the same as before the film thickness was stopped by 3 times was marked as ◯.

(H) Adhesion with the substrate was evaluated based on the JIS K5600-5-6 cross-cut method.

Chemical resistance: A coating film is immersed in a reagent with a cloth soaked with a reagent such as acetone or isopropanol. → ○: No abnormality, ×: Surface abnormality or dissolution

  As is clear from the above examples, according to the polyimide of the present invention, the thermal expansion coefficient after drying and curing is 50 ppm or less, the elastic modulus is 2 GPa or more, and high long-term insulation reliability, flame retardancy, and A polyimide thermosetting resin composition having chemical resistance can be provided.

Claims (12)

The following general formula [I]

(In the formula, Ar ¹ is an arbitrary tetravalent organic group, Ar ² is an arbitrary divalent organic group, and at least one of Ar ¹ and Ar ² has a triple bond)
The polyimide which has a repeating unit represented by these. Ar ¹ is represented by the following general formula [II]:

[II]
(In the formula, E represents a single bond, —C≡C—, —O—, —C (CH ₃ ) ₂ — or —C (CF ₃ ) ₂ —).
The polyimide of Claim 1 represented by these.   The polyimide according to claim 2, wherein E is —C≡C—. Ar ² is represented by the following general formula [III]:

[III]
(Wherein represents -C (CH ₃ ) ₂ -or -C (CF ₃ ) _2- )
The polyimide of any one of Claims 1-3 represented by these. The Ar ² is represented by the following general formula [IV]:

[IV]
(In the formula, X represents —C≡C—, —C (═O) —, —SO ₂ —, —O—, —S—, — (CH ₂ ) _a — (a represents an integer of 1 to 5). Selected from the group consisting of: -NHCO-, -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -C (= O) O- and a single bond, and R ₁ and R ₂ are Independently selected from hydrogen, hydroxyl group, carboxyl group, alkyl group having 1 to 4 carbon atoms, phenyl group, F, Cl and Br (however, p1 and p2 each independently represent an integer of 1 to 4)
The polyimide of any one of Claims 1-3 represented by these. Ar ² is represented by the following general formula [V]:

[V]
Wherein Y and Z are independently of each other —C (═O) —, —SO ₂ —, —O—, —S—, — (CH ₂ ) _a — (a represents an integer of 1 to 5 ), -NHCO-, -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -C (= O) O- and a single bond, R ₃ , R ₄ and R ₅ Are independently selected from hydrogen, hydroxyl group, carboxyl group, alkyl group having 1 to 4 carbon atoms, phenyl group, F, Cl and Br (provided that at least one of R ₃ , R ₄ and R ₅ is An alkyl group having 1 to 4 carbon atoms), and p3, p4 and p5 each independently represent an integer of 1 to 4))
The polyimide of any one of Claims 1-3 represented by these.   The printing ink composition containing the polyimide of any one of Claims 1-6, and the organic solvent which melt | dissolves this polyimide.   The composition according to claim 7, which has a viscosity at 25 ° C of 100 to 50,000 mPa · s.   The composition according to claim 7 or 8, which has a thixotropic coefficient of 1.5 to 10.0.   The composition according to any one of claims 7 to 9, which is an ink composition for a screen printing method, an inkjet method or a dispensing method.   A method for forming an insulating film, comprising: applying the composition according to any one of claims 7 to 9 on a base layer and drying to form an insulating film made of a polyimide film.   The method according to claim 11, wherein the polyimide film is formed by a screen printing method, an inkjet method, or a dispensing method.

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