JPH10251596A - Electric wire coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electric wire coating material excellent in thermal stability, moisture resistance, soldering resistance, low dielectric constant properties and productivity. SOLUTION: This electric wire coating material is obtained by formulating 0.1-50 pts.wt. organic silyl ether compound of the formula RnSi(O-Y)4-n [R is an organic group; Y is an alkyl group or an aryl group; (n) is an integer of 1-3] with 100 pts.wt. polycarbodiimide resin having at least one, preferably six fluorine atoms in a repeating unit and excellent in moisture resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel electric wire coating material, and more particularly to an electric wire coating material for fine wires that can be soldered.

[0002]

2. Description of the Related Art In recent years, as electronic circuits have become smaller and lighter,
BACKGROUND ART Weight reduction and high reliability of electric wires and cables have been promoted, and there is a demand for thinner and thinner coating layers of electric wires and cables. It is very difficult to remove only the resin coated on the extra-fine wire when soldering the electric wire, and it is necessary to use a resin that has solderability. In view of the above, there is a demand for a coating material that is excellent in heat resistance and that does not cause damage such as corrosion to an internal copper wire in a test in a humid atmosphere under a high temperature and a high pressure such as a pressure cooker test (PCT). Further, with the increase in the speed of the CPU, there is a strong demand for lowering the dielectric constant of the resin used as the coating material, and practical wire coating materials are giving rise to practical problems.

Conventionally, silicon-based materials have been used as electric wire coating materials.
Polyurethane-based, polyamide-imide-based, polyimide-based,
Although there is a thermosetting resin such as a polyester resin, it is known that an electric wire coated with a polyurethane resin can be soldered as it is without being peeled off as a feature not seen when coated with another resin, There is a problem that heat resistance is low. For the purpose of improving such heat resistance, JP-A-8-259886 discloses that a resin derived from a carbodiimide-modified diisocyanate and a diol has higher heat resistance than polyurethane, and is excellent in solderability. Have been. However, from the viewpoint of the above-described high reliability and low dielectric constant, it is still difficult to say that the coating material is sufficient.

Conventionally known polycarbodiimide resins are very excellent in heat resistance and moisture resistance in a normal temperature atmosphere, but are extremely unstable in a pressure cooker test, are easily hydrolyzed, and have a low molecular weight. And the mechanical strength of the film is reduced, so that the reliability of covering the electric wire is greatly reduced. Furthermore, a varnish obtained by dissolving only these polycarbodiimide resins in an organic solvent is not only poor in wettability and adhesion to an adherend, but also needs to be cured in order to obtain a sufficiently reliable wire coating. This takes a long time, and there is a problem in productivity.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a wire covering material which overcomes the above-mentioned problems and has excellent heat resistance, moisture resistance, solderability, low dielectric constant and productivity.

[0006]

SUMMARY OF THE INVENTION The present invention has been completed as a result of intensive studies on the above-mentioned problems of the prior art. That is, in the present invention, an organic silyl ether compound represented by the following general formula (1) is blended with a polycarbodiimide resin having at least one fluorine atom in a repeating unit and having excellent moisture resistance. The present invention relates to a wire covering material characterized by the above. RnSi (OY) _4- n (1) (wherein R is an organic group, Y is an alkyl group or an aryl group,
n shows the positive number of 1-3. As the electric wire coating material, it is preferable that 0.1 to 50 parts by weight of an organic silyl ether compound is blended with respect to 100 parts by weight of the above polycarbodiimide resin. It is preferable that the resin contains 6 fluorine atoms, and more preferable is a fluorine-containing polycarbodiimide resin selected from the following general formulas (2) to (5).

[0007]

Embedded image

[0008]

DETAILED DESCRIPTION OF THE INVENTION The polycarbodiimide resin used in the present invention can be synthesized from the corresponding diisocyanate by a known method. For example, LMAlberino et al. (J.appl.Polym.Sci., 21, PP1999 (1977));
As disclosed in JP-A-292316 and JP-A-4-275359, it can be obtained by reacting an organic diisocyanate in an organic solvent in the presence of a carbodiimidization catalyst. As the diisocyanate that can be used, a diisocyanate having at least one fluorine atom, preferably six fluorine atoms in one molecule is used. Specific examples include 2,2-bis (4-isocyanatophenoxyphenyl) hexafluoropropane, 2,2-bis (4-phenylisocyanate) hexafluoropropane, and 2,2′-bis (3-
Isocyanate-4-methylphenyl) hexafluoropropane and 2,2′-bis (trifluoromethyl) biphenyl-4,4′-diisocyanate give a fluorinated polycarbodiimide resin of the above general formulas (2) to (5). The raw material is most preferable in terms of polymerization reactivity, heat resistance, moisture resistance, film formability, flexibility and the like. In addition, propane hexafluoro-1,3-diisocyanate, bis (4-phenylisocyanate) difluoroethylene, butane octafluoride-
1,4-diisocyanate, octane hexafluoride-1,
8-Diisocyanate, 1-trifluoromethylbenzene-3,4-diisocyanate, 1-trifluoromethylbenzene-2,4-diisocyanate, 2-trifluoromethylbenzene-1,4-diisocyanate and the like are used.

Further, the corresponding diamine compound can be produced in one pot in the presence of a halogenated formate, a carbodiimidization catalyst, a basic compound and an organosilicon compound. The corresponding diamine compounds include 2,2-bis (4-aminophenoxyphenyl) hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, and 2,2′-bis (3-amino-4 -Methylphenyl) hexafluoropropane, 2,2'-bis (trifluoromethyl) biphenyl-4,4'-diamine, propane hexafluoro-1,3-diamine, bis (4-
Aminophenyl) difluoroethylene, butane octafluoride-1,4-diamine, octane hexafluoro-1,8-diamine, 1-trifluoromethylbenzene-3,4-diamine, 1-trifluoromethylbenzene-2 , 4-diamine, 2-trifluoromethylbenzene-1,4-diamine and the like.

The reaction solvent is not particularly limited as long as it dissolves or suspends a diamine compound. Examples thereof include ether compounds such as tetrahydrofuran, diethyl ether and dioxane, ketone compounds such as acetone and methyl ethyl ketone, ester compounds such as ethyl acetate, and toluene. ,
Examples include hydrocarbon compounds such as xylene and benzene, and halogenated hydrocarbon compounds such as chloroform and methylene chloride. These solvents may be used alone or as a mixture of two or more. In some cases, the reaction temperature can be changed by substituting part or all of the reaction during the reaction.

As a method for producing a polycarbodiimide from a diamine compound in one pot, for example, as a first step of the reaction, the corresponding diamine is added to methyl chloroformate, ethyl chloroformate, phenyl chloroformate, p-nitrophenyl chloroformate. Bisurethane is synthesized by the action of a halogenated formate such as a mate. In particular, phenylchloroformate or p-nitrophenylchloroformate is more suitable for obtaining fully activated bisurethane for obtaining polycarbodiimide. The reaction temperature is -40 to 110C, preferably -20 to 90C, and most preferably 0 to 80C. -4
At 0 ° C. or lower, the reaction hardly proceeds, and at a high temperature of 110 ° C. or higher, side reactions such as condensation may occur.

As the basic compound for trapping hydrogen chloride generated when bisurethane is produced, an organic base or an inorganic base can be used, but an organic base is more suitable because it is easily dissolved in a solvent. Furthermore, tertiary amines such as triethylamine and pyridine are suitable because they do not inhibit the reaction among organic bases. Primary amines and secondary amines are not preferred because they have active hydrogen and may react with isocyanates which are considered to be formed as reaction intermediates. The amount of the basic compound used is 0.1 to 10 times, preferably 1 to 8 times, and most preferably 2 to 6 times the mole of the diamine used. 0.
If it is less than 1 mole, the reaction hardly proceeds, and if it is 10 moles or more, undesired side reactions may occur. Next, an organosilicon compound is used as a reaction catalyst for obtaining polycarbodiimide from bisurethane. In particular, chlorosilanes such as trimethylchlorosilane, triethylchlorosilane, trimethoxychlorosilane, and tetrachlorosilane are preferred, but trimethylchlorosilane is most preferred in terms of ease of handling and economy.

The amount of the organosilicon compound used is 0.1 to 10 times, preferably 0.5 to 7 times, and most preferably 1 to 4 times the mole of the produced bisurethane. If the amount is too small, unreacted raw materials may remain.
If the amount is too large, it may be difficult to remove after the reaction is completed, or an undesirable side reaction may occur. Examples of the polymerization catalyst include 1-phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide,
-Ethyl-2-phospholene-1-oxide, 3-methyl-1-phenyl-3-phospholene-1-oxide, 3-
Phosphorene oxides such as methyl-1-phenyl-2-phospholene-1-oxide or their 2- or 3-phosphorene isomers can be used. These are generally used in an amount of 0.05 to 50 mol% of bisurethane,
Preferably 0.1-40 mol%, optimally 0.5-30
mol%. If the amount is too small, it may be deactivated during the reaction and the polymerization may be stopped. If the amount is too large, it may be difficult to control the reaction. In addition, these polymerization catalysts,
It may be present from the beginning of the reaction, or may be added after the reaction of the bisurethane with the organosilicon compound or the basic compound has proceeded first. In the one-pot production method, a diamine is carbodiimidated in the presence of a halogenated formate, a carbodiimidation catalyst, a basic compound and an organosilicon compound, and the order of the reaction and the like can be appropriately selected.

The reaction temperature at which the polymerization reaction proceeds is generally from 0 to 200 ° C., preferably from 20 to 150 ° C., more preferably from 40 to 120 ° C., and can be appropriately changed depending on the combination of the diamine and the organosilicon compound used. it can. If the reaction temperature is too low, the reaction may not proceed at all. Conversely, if the reaction temperature is raised too much or heated for too long, undesired side reactions may occur or the product may be decomposed. It is better to proceed.
The diamine concentration in the reaction mixture is between 1 and 50%, preferably between 5 and 40%, optimally between 10 and 30%. If the concentration is too low, the reaction requires time, which is not practical. If the concentration is too high, an undesirable side reaction may be caused.

The terminal blocking treatment can be carried out by adding a monoisocyanate, a urethane compound or a monoamine during any of the last, middle and early stages of the reaction or throughout the entire reaction. By this treatment, the storage stability of the polycarbodiimide solution can be improved. As the monoisocyanate, phenyl isocyanate, p-nitrophenyl isocyanate, p- and m-tolyl isocyanate, p-formylphenyl isocyanate and the like can be used. Examples of the urethane compound include phenyl urethane and 2-phenoxyphenyl-2- (4-
(Phenoxyphenylurethane) hexafluoropropane, p- and m-tolylurethane, and the like can be used. As monoamines, 1-naphthylamine, p-
And m-tolylamine, phenoxyphenylamine and the like. The polycarbodiimide solution obtained in this manner is preferable in that the solution has excellent storage stability.

After completion of the reaction, the polycarbodiimide can be isolated and purified by a conventional method. That is, a method of removing the hydrochloride salt generated by the reaction and excess reaction reagent and taking out polycarbodiimide as a solution, or a method of pouring the reaction mixture into a poor solvent such as lower hydrocarbons / alcohol to precipitate the polymer as a precipitate. There is. After being precipitated as a precipitate, it is washed and dried by a predetermined operation, and the polycarbodiimide can be taken out as a solid. The molecular weight of the polycarbodiimide is such that the repeating unit n is 2 to 400,
Preferably 10 to 200, 2,000 to 100,0 in number average molecular weight
00, preferably 4,000 to 20,000. If the molecular weight is too high, storage stability will be poor, which is not practically preferable. If the molecular weight is too low, it is not preferable because the reliability of the film is poor. In the polymerization of the polycarbodiimide used in the present invention, it is possible to copolymerize with another diisocyanate and another diamine. The copolymerization ratio should be within a range that does not impair the properties of the fluorinated polycarbodiimide, and is 50 mol% or less, preferably 30 mol% or less. Specifically, aromatic, aliphatic, alicyclic, and aliphatic-aromatic diisocyanates and diamines containing no fluorine atom can be used. Further, silicon diamines such as dimethyl silicon diamine and diphenyl silicon diamine, and phosphorus-containing diamines such as phenyl phosphorus diamine and methoxy phosphorus diamine can also be used.

The wire covering material of the present invention can be obtained by blending an organic silyl ether compound with the thus obtained fluorinated polycarbodiimide solution and adjusting the viscosity with an organic solvent. If it is necessary to avoid the contamination of impurities, isolate the fluorinated polycarbodiimide
After purification, it may be dissolved in an organic solvent, and an organic silyl ether compound may be blended to obtain a wire covering material. Such an organic solvent may be any as long as it dissolves polycarbodiimide, and examples thereof include ether compounds such as tetrahydrofuran, diethyl ether and dioxane, ketone compounds such as acetone and methyl ethyl ketone, ester compounds such as ethyl acetate, toluene, and xylene. And hydrocarbon compounds such as benzene, and halogenated hydrocarbon compounds such as chloroform and methylene chloride. It is preferable to use a hydrocarbon solvent such as toluene or xylene from the viewpoints of coatability, safety and economy.

The organic silyl ether compound used in the present invention is compounded for imparting adhesiveness, slipperiness and the like to a wire coating material, and is a compound represented by the following general formula (1): RnSi ( OY) _4- n (1). R in the formula
Is an organic group, and Y is an alkyl group or an aryl group, which may be the same or different. n is selected from 1 to 3. When n = 1, a compound such as a generally known silane coupling agent can be used. Specifically, γ-aminopropyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl)
Ethyltrimethoxysilane, N-β (aminoethyl) γ
-Aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercapropropyltrimethoxysilane, γ-chloropropyltrimethoxysilane and the like can be used. Also, n =
In the case of 2, in addition to a silane coupling agent such as γ-glycidoxypropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, dimethyldimethoxysilane, diphenyldimethoxysilane, dimethyldimethoxysilane Ethoxysilane, diphenyldiethoxysilane, or the like can be used. Also, n =
In the case of 3, a trialkylsilyl ether such as phenyltrimethylsilyl ether and methyltrimethylsilyl ether can be used. From the viewpoint of solution stability and wettability, it is desirable to use a trialkylsilyl ether with n = 3. These organic silyl ether compounds are used in an amount of 0.1 to 100 parts by weight of the polycarbodiimide.
100 parts by weight, preferably 1 to 70 parts by weight. When the amount is less than 0.1 part by weight, the effect of addition is small, and when the amount is more than 100 parts by weight, the reliability of the film becomes poor.

The wire covering material of the present invention is provided in a state where the polycarbodiimide and the organic silyl ether compound are dissolved in an organic solvent. The amount of the polycarbodiimide as a solid resin component dissolved in the organic solvent is as follows. , 1 to 70% by weight, preferably 10 to 50% by weight. When the content is 1% by weight or less, there is a problem that a film thickness required for securing electrical insulation cannot be secured, which is not preferable. On the other hand, if the solid content is 70% by weight or more, the viscosity of the solution becomes high, which is not preferable for coating a very fine wire. The wire coating material of the present invention is applied to a bare wire such as a copper wire, and then dried by an organic solvent,
It can be a wire coating. The coating temperature can be gradually raised at a temperature of 500 ° C. or less to form a film. However, after preliminarily drying the solvent at a low temperature, heat treatment can also be performed.

The temperature of the pre-drying depends on the type of the solvent,
The temperature is 20 to 300 ° C, preferably 50 to 120 ° C. If the temperature of the preliminary drying is lower than 20 ° C., the solvent may remain in the film. On the other hand, if the temperature is higher than 300 ° C., the solvent foams and microvoids are generated, and a uniform coating film cannot be formed. These coatings may be repeated twice or more and several times to several tens of times. By repeating the process, a film thickness can be secured and a uniform film thickness can be obtained. Further, it is necessary to perform the heat treatment at a temperature of 500 ° C. or lower, and if the heat treatment is performed at a temperature of 500 ° C. or higher, thermal decomposition of polycarbodiimide occurs and the film is deteriorated, which is not preferable. The heat treatment time varies depending on the heat treatment temperature.
It is preferably performed within 30 minutes or 2 minutes at 400 ° C. If the heat treatment is performed for a longer time than this, the thermosetting of the polycarbodiimide resin is completely advanced, and the solderability is deteriorated. This heat treatment step can be performed all at once, or may be performed following the step of removing the organic solvent. By performing such a heat treatment, the heat resistance of the film can be improved,
An effect of improving reliability can be expected.

[0021]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 In a 1-L three-necked flask equipped with a dropping funnel, 40.0 g (77.2 mmol) of 2,2-bis (4-aminophenoxyphenyl) hexafluoropropane, 530 g of methylene chloride,
34.4 g (339 mmol) of triethylamine was charged. 24.2 g (154 mmo) of phenyl chloroformate was added to the dropping funnel.
l) and the reaction vessel was cooled to 0 ° C. in an ice bath. Phenyl chloroformate was added dropwise over 15 minutes, and the mixture was stirred for 12 hours while returning to room temperature. A cooling tube with a calcium chloride tube was attached to the same flask. 0.104 g (0.540 mmol) of a carbodiimidization catalyst (3-methyl-1-phenyl-2-phospholene-1-oxide) was placed in a flask, and the inside was replaced with argon. At room temperature, 18.4 g (170 mmol) of trimethylchlorosilane was added, and the mixture was stirred for 10 minutes. While replacing methylene chloride with an equal amount of toluene, the reaction temperature was gradually increased from room temperature to 80 ° C. over 2 hours, followed by stirring at 80 ° C. for 4 hours. After confirming that the carbodiimidization was completed by IR, 20.5 g (154 mmol) of m-tolyl isocyanate was added, and the mixture was further stirred at 80 ° C for 1.5 hours. The reaction solution was poured into 3160 g of methanol with stirring, and the precipitate was collected and dried under reduced pressure. The obtained white powdery polymer was soluble in an organic solvent and the yield was 36.0 g (90% yield), Mn = 8,400, Mw = 26,000, intrinsic viscosity ηinh
Was 0.1. 100 parts by weight of the polycarbodiimide thus obtained and 10 parts by weight of phenyltrimethylsilyl ether as an organic silyl ether compound were added to 300 parts of toluene.
It melt | dissolved in weight part, and obtained the electric wire coating material of this invention. The viscosity of this varnish was measured at 25 ° C with an E-type viscometer at a rotation speed of 0.5 rpm.
Was 150 mPa · s.

Example 2 The present invention was carried out in the same manner as in Example 1 except that 2,2′-bis (3-aminophenyl) hexafluoropropane was used as a polycarbodiimide monomer and 5 parts by weight of phenyltrimethylsilyl ether was used. An electric wire covering material was obtained. This varnish has a viscosity of 160 mPa · s at 25 ° C and 0.5 rpm.
Met.

Example 3 The procedure of Example 1 was repeated except that 2,2′-bis (3-amino-4-methylphenyl) hexafluoropropane was used as the polycarbodiimide monomer and 20 parts by weight of phenyltrimethylsilyl ether was used. Thus, the wire covering material of the present invention was obtained. The varnish has a viscosity of 13 at 25 ° C and 0.5 rpm.
It was 0 mPa · s.

Example 4 An electric wire coating material of the present invention was obtained in the same manner as in Example 1 except that 2,2'-bis (trifluoromethyl) biphenyl-4,4'-diamine was used as a polycarbodiimide monomer. Was. The varnish has a viscosity of 150 at 25 ° C and 0.5 rpm.
mPa · s.

Comparative Example 1 An electric wire coating material was obtained in the same manner as in Example 1 except that diphenylmethane-4,4'-diamine was used as a polycarbodiimide monomer and tetrahydrofuran was used as a varnish (?) Solvent. . The varnish has a viscosity of 25
It was 160 mPa · s at 0.5 ° C. and 0.5 rpm.

Comparative Example 2 An electric wire covering material was obtained in the same manner as in Example 1, except that 1-methylbenzene-2,4-diamine was used as a polycarbodiimide monomer. The viscosity of this varnish is 25 ℃,
130 mPa · s at 0.5 rpm.

Comparative Example 3 An electric wire coating material was obtained in the same manner as in Example 1 except that a varnish prepared by dissolving only polycarbodiimide in toluene was used. Examples 1 to 4 and Comparative Examples 1 to 3 above
About, each wire coating material (varnish) is applied 5 times to a bare soft copper wire conductor having a diameter of 100 μm, and pre-dried at 90 ° C. for 30 minutes.
Heat treatment was performed at 250 ° C. for 20 minutes to obtain a coated electric wire. The test results are shown in Table 1.

[Test Method] (1) Dielectric constant, dielectric loss tangent, and volume resistivity: The electric wire covering material synthesized in each of Examples and Comparative Examples was formed into a sheet, one surface having a circular shape having a diameter of 2 cm, and the other surface. The surface of was subjected to gold deposition on the entire surface to form an electrode surface, and the measurement was performed. The dielectric constant and dielectric loss tangent were measured by Hewlett-Packard's 4284A PRECISION LCR.
It was measured using METER. The volume resistivity was measured using R8340A ULTRA HIGH RESISTANCE METER manufactured by Advantest. (2) Solderability: After being immersed in a solder bath at 400 ° C. for 2 seconds, it was visually checked whether or not the coating had melted and had solder. (3) Appearance of electric wire: good film condition; 皮膜, damaged film; × (4) Adhesion: Adhesion to bare soft copper wire was visually observed. (5) PCT (pressure cooker test): 121 ° C x
Conditions of 2 atm. × 100% RH In Table 1, for the samples of Comparative Examples 1 and 2, various electric characteristics could not be measured because the coating was significantly embrittled after 100 hours of PCT.

[0029]

Since the electric wire coating material of the present invention uses a fluorine-containing polycarbodiimide having a specific structure and an organic silyl ether compound, the electric wire coated with this material has heat resistance and moisture resistance, especially a pressure cooker test. In addition to having durability in a high-pressure and high-humidity environment as described above, a low dielectric constant can be achieved, so that high-speed transmission is excellent and electrical problems such as crosstalk noise can be eliminated. Further, a highly reliable coated electric wire can be provided, which is extremely useful industrially.

[0030]

[Table 1]

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Torue Sakamoto 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Yuji Hotta 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation

Claims (4)

[Claims] An organic silyl ether compound represented by the following general formula (1) is compounded with a polycarbodiimide resin having at least one fluorine atom in a repeating unit and having excellent moisture resistance. A wire covering material characterized by the above-mentioned. RnSi (OY) _4- n (1) (wherein R is an organic group, Y is an alkyl group or an aryl group,
n shows the positive number of 1-3. ) 2. The electric wire covering material according to claim 1, wherein 0.1 to 50 parts by weight of an organic silyl ether compound is blended with respect to 100 parts by weight of the polycarbodiimide resin. 3. The electric wire covering material according to claim 1, wherein the polycarbodiimide resin contains 6 fluorine atoms in its repeating unit. 4. The wire covering material according to claim 3, wherein the polycarbodiimide resin is a fluorine-containing polycarbodiimide resin selected from the following general formulas (2) to (5). Embedded image