JP2000169752A - Photosensitive resin composition for coating electronic circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition for protectively coating electronic circuit that is curable by light irradiation within a short time and has flexibility and the resistance to electrolytic solution, water, ionic drinking water or the like. SOLUTION: The photosensitive resin composition comprises as essential components an unsaturated polyurethane having an ethylenically unsaturated bond with the molecule and having a number average molecular weight, when converted into polystyrene, as measured by GPC of 800-13,000, an ethylenically unsaturated compound having an ethylenically unsaturated bond and having a molecular weight of smaller than 800, and a photopolymerization initiator. These essential components can impart to the photosensitive resin composition the resistance to electrolytic solution that has leaked out on an electronic circuit, water or ionic drinking water which a user has inadvertently spilled thereon, or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a hybrid IC,
A photosensitive resin used to cover electronic circuits such as mounting circuits so that they do not malfunction when exposed to leaked electrolyte, spilled water, ionic drinking water, etc. Composition.

[0002]

2. Description of the Related Art Under severe conditions of electronic circuits, pin feet and connectors of mounted components such as capacitors and transistors may be corroded or dewed by moisture, dust, acid gas, etc. In such a case, there is a danger that the hybrid IC and the mounted circuit board may not operate properly. In the case of a mobile phone or the like that uses a lithium ion secondary battery, it may be used when taking a bath or while drinking ionic drinking water, etc. When the battery is spilled, there is a danger that the connected protection circuit is short-circuited and does not operate, causing a battery runaway.

In addition, when the electrolyte leaks from the battery, the electrolyte comes into contact with the protection circuit, impairing its function and generating heat.

In order to solve such a problem, the surface of an electronic circuit is coated with a resin to protect the surface. However, when such a resin is coated to form a strong film, a high temperature is required. Has to be cured and the function of the electronic circuit is impaired. Japanese Patent Application Laid-Open No. 61-278845 proposes forming a protective film by applying a photocurable moisture-proof insulating paint made of a diene rubber to a part or the whole of a hybrid IC and a mounting circuit board. According to this method, it is possible to cure at a low temperature, but there is a problem that curing is slow in ordinary exposure in the air, and the cured product has tackiness and is difficult to handle thereafter. I was

[0005]

The object of the present invention is to provide a photosensitive resin composition for an electronic circuit protective coat which is curable at a low temperature, has flexibility, and has resistance to electrolytes, water, ionic drinking water and the like. It is an object of the present invention to provide a photosensitive resin composition for an electronic circuit protective coat that can be cured by short-time light irradiation in air.

[0006]

DISCLOSURE OF THE INVENTION The present inventors have set forth the above-mentioned object as having a polystyrene-equivalent number average molecular weight of 800 to 130, having an ethylenically unsaturated bond in the molecule, based on GPC measurement.
The present invention has been completed by solving the problem by using an unsaturated polyurethane having a molecular weight of less than 800, an ethylenically unsaturated compound having an ethylenically unsaturated bond and having a molecular weight of less than 800, and a photosensitive resin composition comprising a photopolymerization initiator as essential components. did.

Hereinafter, the present invention will be described in detail. The photosensitive resin composition for coating an electronic circuit of the present invention has a polystyrene-equivalent number average molecular weight of 800 to 13 based on GPC measurement and having an ethylenically unsaturated bond in the molecule.
000 unsaturated polyurethane, an ethylenically unsaturated compound having an ethylenically unsaturated bond and having a molecular weight of less than 800, and a photopolymerization initiator. The number average molecular weight in terms of polystyrene based on GPC measurement having an ethylenically unsaturated bond in the molecule is 800 to 1300.
The unsaturated polyurethane of 0 is obtained by reacting a diol compound with a diisocyanate compound and then reacting a compound having an ethylenically unsaturated bond with a hydroxyl group or an amino group or a compound having an ethylenically unsaturated bond with an isocyanate group at the same time. Can be

In a method of first synthesizing a polyurethane polymer having isocyanate groups at both terminals and reacting it with a compound having both a hydroxyl group and an ethylenically unsaturated bond, the compound having both a hydroxyl group and an ethylenically unsaturated bond is not reacted at both terminals. In order to facilitate the reaction with the polyurethane polymer having an isocyanate group and to terminate the reaction in a short time by suppressing side reactions, the reaction is performed by adding the number of hydroxyl groups to the number of isocyanate groups in excess. Is preferred. Usually, an excess of about 2 to 5 times the required amount is added. The result is a mixture of a polyurethane polymer having ethylenically unsaturated bonds and an excess of hydroxyl-containing ethylenically unsaturated compounds.

In a method of first synthesizing a polyurethane polymer having hydroxyl groups at both ends and reacting it with a compound having both an isocyanate group and an ethylenically unsaturated bond, the compound having both an isocyanate group and an ethylenically unsaturated bond is a polyurethane polymer. It is generally added in the same or less range as the number of hydroxyl groups of the polymer, but in this case, in order to facilitate stirring and suppress side reactions,
It is preferable to reduce the viscosity of the reaction system by using a component not involved in the urethanization reaction as a diluent. When a compound having both an isocyanate group and an ethylenically unsaturated bond is added in excess, it is necessary to eliminate the isocyanate group by adding a compound having an active hydrogen such as a hydroxyl group after completion of the reaction.

As the diol compound, compounds having two hydroxyl groups in one molecule, for example, polyester diols such as polypropylene glycol adipate diol, polyneopentyl glycol adipate diol, polybutylene glycol adipate diol, polycaprolactone diol, and polyvalerolactone diol; , Polyethylene glycol diol, polypropylene glycol,
Examples thereof include polyester diols such as polytetramethylene glycol, polybutadiene having a terminal hydroxyl group and hydrogenated products thereof, and polyisoprene having a terminal hydroxyl group and hydrogenated products thereof.

The molecular weight determined from the hydroxyl value of the diol compound is about 400 to 4000, but from the viewpoint of obtaining a more flexible and strong product, it is 500 to 2500.
It is preferable to use one having a molecular weight of the order. Examples of the diisocyanate compound include compounds having two isocyanate groups, such as tolylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, and isophorone diisocyanate.
Among these, tolylene diisocyanate is preferred because the viscosity is not so increased and a flexible and strong product is easily obtained.

Examples of the compound having both a hydroxyl group and an ethylenically unsaturated group include hydroxyethyl methacrylate,
Hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, N-
Examples include methylol acrylamide, polyoxyethylene glycol monomethacrylate, polyoxypropylene glycol monomethacrylate, and the like. Of these, hydroxyethyl methacrylate and hydroxypropyl methacrylate are preferred from the viewpoint of flexibility and strength, and hydroxypropyl methacrylate having excellent water resistance is most preferred.

Examples of the compound having an isocyanate group and an ethylenically unsaturated group at the same time include those obtained by adding a diisocyanate compound to a compound having a hydroxyl group and an ethylenically unsaturated group at a ratio of 1: 1. . The unsaturated polyurethane obtained as described above preferably has a number average molecular weight of 800 to 13,000 determined by GPC measurement using polystyrene as a standard. Although the viscosity of the obtained photosensitive resin composition can be lowered as the molecular weight is smaller, the cured resin loses flexibility when the molecular weight is smaller than this, and the adhesion to a substrate or the like is impaired. Not preferred.

When the molecular weight is large, the flexibility of the cured product is easily secured, but when the molecular weight is larger than this, the viscosity of the obtained photosensitive resin composition becomes high, and the coating on the electronic circuit becomes easy, for example, air bubbles are easily entrained in the uneven portions. It becomes difficult to do. It is effective to introduce a polar group such as a carboxyl group into the unsaturated polyurethane in order to enhance the adhesion to a substrate or the like. Introduction of carboxyl groups into unsaturated polyurethane
After the urethane polymer of both terminal isocyanate groups,
A compound having two hydroxyl groups and an ethylenically unsaturated bond at the same time is added, and one of the hydroxyl groups is reacted with an isocyanate group to obtain an unsaturated polyurethane having two hydroxyl groups and two ethylenically unsaturated bonds in the molecule. Further, by addition of an acid anhydride and ring-opening addition, an unsaturated polyurethane having a carboxyl group and an ethylenically unsaturated bond at both terminals simultaneously can be obtained.

Examples of the compound having two hydroxyl groups and an ethylenically unsaturated bond used herein include primary and secondary hydroxyl groups such as a compound obtained by adding water to glycidyl methacrylate or acrylate to open an epoxy group. Is used. By utilizing the difference in reactivity between the primary hydroxyl group and the secondary hydroxyl group, it is possible to obtain an unsaturated polyurethane having hydroxyl groups at both ends in which only one hydroxyl group in the molecule has reacted with an isocyanate group.

Molecular weight having an ethylenically unsaturated bond 80
Examples of the ethylenically unsaturated compound less than 0 include hydroxyethyl methacrylate and acrylate, hydroxyalkyl methacrylate and acrylates such as hydroxypropyl acrylate and methacrylate, isobornyl acrylate and methacrylate, cyclohexyl methacrylate and acrylate, benzyl acrylate and methacrylate, and phenyl acrylate. And dimethacrylates and diacrylates of polyoxyethylene glycol such as methacrylate, diethylene glycol dimethacrylate and diacrylate, tetraethylene glycol dimethacrylate and diacrylate, propylene glycol dimethacrylate and diacrylate, dipropylene glycol dimethacrylate and diacrylate, trip Pyrene glycol dimethacrylate and diacrylate, butanediol dimethacrylate and diacrylate, hexanediol dimethacrylate and diacrylate, nonanediol diacrylate and dimethacrylate, trimethylolpropane trimethacrylate and triacrylate, dimethacrylate and diacrylate having a bisphenol skeleton , N-methylol acrylamide, diacetone acrylamide,
Examples thereof include N-substituted acrylamides such as N, N-dimethylacrylamide, N- (2-methoxyethyl) acrylamide, N-methylol methacrylamide, and N, N-dimethylmethacrylamide, and methacrylamides.

Of these, hydroxyalkyl methacrylates and acrylates, isobornyl acrylate, cyclohexyl acrylate, benzyl acrylate, and the like are suitable from the viewpoint of enhancing the adhesion to electronic circuit equipment. Particularly, hydroxyethyl methacrylate, acrylate, and isobornyl acrylate are effective. Hydroxyalkyl methacrylates and acrylates have high hygroscopicity, so that their proportion in the photosensitive resin composition preferably does not exceed 50%. Hydroxypropyl methacrylate and acrylate have an advantage that they have a slightly smaller effect of enhancing adhesion than hydroxyethyl methacrylate and acrylate, but have low hygroscopicity. Isobornyl acrylate is most suitable because it hardly absorbs moisture.

The use of acrylates is effective for enhancing the curability upon exposure in air. In particular, polyfunctional acrylates such as diacrylate and triacrylate are highly effective. Usually, these compounds are used in combination as the ethylenically unsaturated compound having an ethylenically unsaturated bond and having a molecular weight of less than 800. Usually, based on GPC measurement having an ethylenically unsaturated bond in the molecule, 100 parts by weight of an unsaturated polyurethane having a number average molecular weight of 800 to 13,000 in terms of polystyrene, and ethylenically unsaturated having a molecular weight of less than 800 having an ethylenically unsaturated bond. The compound is
50 to 500 parts by weight, preferably 50 to 300 parts by weight,
Particularly preferably, it is used in the range of 50 to 200 parts by weight.

As the photopolymerization initiator used in the photosensitive resin composition, those having a capability of absorbing ultraviolet rays having a wavelength of 300 to 400 nm and initiating polymerization, and known ones are used. For example, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin-n-
Benzoin derivatives such as butyl ether, α-methylol benzoin methyl ether, α-methoxybenzoin methyl ether, α-ethoxybenzoin ethyl ether, benzophenone, 1-hydroxycyclohexylphenylacetophenone, 1-benzyl-1-dimethylaminopropyl-p -Morpholinoketone and the like. Among them, α-methoxybenzoin methyl ether is preferable because it can cure a coating film having a large curing rate and a large thickness.

The photopolymerization initiator may be used alone or in combination. The amount of the photopolymerization initiator may be any amount as long as it is an effective amount for initiating polymerization, and is usually 0.1 to 0.1% based on the total weight of the photosensitive resin composition.
Used in the range of 10% by weight. If the amount is less than this, the photopolymerization initiation efficiency is deteriorated, and if it is too large, the mechanical properties of the cured product are deteriorated. Further, with respect to the curability in the exposure in the air, it is advantageous that the amount of addition is large. A preferred range is 1 to 6% by weight, particularly preferred is 3 to 5% by weight.

It is effective to use these photopolymerization initiators in combination with a compound having an amino group in order to enhance the curability upon exposure in air. Examples of the compound having an amino group include dimethylaminobenzophenone, dimethylaminobenzoic acid isoamyl ester, and the like, but its own ultraviolet absorption is not so large,
Particularly preferred is dimethylaminobenzoic acid isoamyl ester, which does not hinder the curing of thick coatings. The compound having an amino group is present in an amount of 1 to 1 with respect to the total weight of the photosensitive resin composition.
It is used in the range of 0% by weight, preferably 3 to 10% by weight, particularly preferably 5 to 10% by weight. As the compound having an amino group, diethylaminoethyl methacrylate having an amino group and an ethylenically unsaturated bond at the same time can be used. In this case, the addition amount may be within the addition amount range of the ethylenically unsaturated compound having a molecular weight of less than 800. It is also effective to use benzophenone as a photopolymerization initiator.

In addition, a stabilizer such as a known thermal polymerization inhibitor can be added to secure the stability of the photosensitive resin during production or storage. Examples of such stabilizers include p-methoxyphenol, 2,6-di-t-butyl-p-cresol, and the like. Further, in order to further increase the resistance to the electrolytic solution used in the lithium ion secondary battery, it is effective to add a filler having a hydroxyl group.

Examples of such fillers include silicas. The shape of the filler is not particularly limited, but a spherical shape having pores on the surface is preferable because it is easily available. The average particle size is not limited, but is 20 μm.
The following ones, particularly those having a size of 12 μm or less, are preferred in that they are difficult to separate and settle in the photosensitive resin. The size of the pores on the surface is not particularly limited, but those having a size of about 0.001 to 0.03 μm are used. In addition, those in which the hydroxyl groups on the surface have been eliminated by the treatment have no effect of increasing the resistance to the electrolytic solution.

The amount of the filler having a hydroxyl group is 2 to 30% by weight based on the total weight of the photosensitive resin composition. Preferably 5
It is added in an amount of 15% by weight, particularly preferably in the range of 8 to 12% by weight. If the amount is too large, the viscosity becomes too high, and it is difficult to coat, and if the amount is too small, the effect cannot be obtained. Although the filler having a hydroxyl group has an effect of increasing the resistance to the electrolytic solution, it does not impair the resistance to the ionic drinking water. Has the advantage that it can be dealt with only by coating one resin.

In order to make it easy for bubbles generated during the operation to escape, the viscosity of the photosensitive resin composition at 20 ° C. is 300 poise or less, preferably 200 poise or less, particularly preferably 1 poise or less.
Desirably, it is 50 poise or less. The viscosity of the photosensitive resin composition can be reduced by increasing the blending ratio of the ethylenically unsaturated compound having a molecular weight of less than 800, particularly the liquid ethylenically unsaturated compound. Among the liquid ethylenically unsaturated compounds, those having a small molecular weight are particularly effective in lowering the viscosity. It is also effective to reduce the viscosity by adding liquid plasticizers in a range that does not significantly affect other properties such as adhesion.

The viscosity can be lowered by raising the temperature of the photosensitive resin composition at the time of use, but the temperature may be deteriorated depending on the temperature. . The light source used to cure the composition may emit ultraviolet light having a wavelength of 300 to 400 nm, and may be an ultraviolet fluorescent lamp, a high-pressure mercury lamp,
A metal halide lamp, a xenon lamp, or the like commonly used for curing a photosensitive resin can be used.

When the photosensitive resin composition is cured in air, it is effective to irradiate ultraviolet rays having a wavelength of less than 300 nm together to prevent the curing of the surface layer from being inhibited by oxygen in the air. It is a target. When a light source that simultaneously emits ultraviolet light having a wavelength of less than 300 nm, such as a high-pressure mercury lamp or a metal halide lamp, is used, the desired effect can be obtained by not passing through a filter. When a light source that emits only ultraviolet light having a wavelength of 300 nm or more, such as an ultraviolet fluorescent lamp, is used together with a light source having a center wavelength of 254 nm, such as a germicidal lamp, the curability in the air can be enhanced. In this case, in order to obtain a uniform cured surface, it is desirable to irradiate ultraviolet rays having a wavelength of 300 nm or more before or simultaneously with irradiation of ultraviolet rays having a wavelength of less than 300 nm. The coating of the electronic circuit with the photosensitive resin can be performed by immersing the electronic circuit in the photosensitive resin composition, coating with a brush or the like, mechanically coating with a dispenser, or molding the electronic circuit. It can be performed by a known method such as a method in which the photosensitive resin is poured into the frame and embedded.

The electronic circuit referred to in the present invention is an electronic circuit in which at least one element such as an LSI, a transistor, a capacitor, an FET, a voltage detecting element, a fuse, a thermistor, and a resistance element is incorporated. Also includes those mounted on substrates such as paper phenolic resin substrates and alumina substrates. Particularly when a cured film of the photosensitive resin composition of the present invention is formed, a voltage detecting element,
Significant effects are found for electronic circuits including environmentally sensitive elements such as FETs.

Further, according to the present invention, excellent effects are exhibited in a battery connected to an electronic circuit on which a cured film of the photosensitive resin composition of the present invention is formed. That is, when an electronic circuit on which a cured film of the photosensitive resin composition of the present invention is formed is connected to a nickel-cadmium battery, an alkaline secondary battery such as a nickel metal hydride battery, a lithium ion secondary battery, Even if the liquid comes into contact with the leaking electronic circuit, it has a strong resistance, and troubles such as abnormal voltage detection and abnormal switching function can be avoided. In particular, electronic circuits connected to such batteries often perform important functions such as charge control, overcharge prevention control, overdischarge prevention control, and the like. A great effect can be obtained from the viewpoint of.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the following examples.

(Example 1) 300 g of polypropylene glycol adipate diol having an average molecular weight of 2500 determined from the hydroxyl value and polyethylene glycol / polypropylene glycol / polyethylene glycol block copolymer diol having an average molecular weight of 2,500 (polypropylene glycol content: 60% by weight) 300 g and 84 g of tolylene diisocyanate were reacted to introduce isocyanates at both ends. Then 38 g of glycerin monomethacrylate
To give a polymer having hydroxyl groups and methacrylate groups at both ends, and further add 24 g of succinic anhydride to carry out a ring-opening addition reaction to obtain an unsaturated polyurethane (A) having methacrylate groups and carboxyl groups at both ends. Was.

100 g of the above unsaturated polyurethane (A),
Hydroxyethyl methacrylate 30 g, tetraethylene glycol diacrylate 22 g, pentaerythritol triacrylate 11 g, α-methoxybenzoin methyl ether 6 g, benzophenone 1.5 g, p-dimethylaminobenzoic acid isoamyl ester 15 g, 2,
0.2 g of 6-di-t-butyl-p-cresol was mixed to obtain a photosensitive resin composition having a viscosity of 60 poise at 20 ° C. A protective circuit board for a lithium ion secondary battery with a lead wire is immersed in the photosensitive resin composition (A), and then applied by pulling up and applying ultraviolet rays from a 3 KW high-pressure mercury lamp at 900 mJ / cm ^{2 on} each side. Irradiation on both sides resulted in a cured film without tackiness.

After connecting the lead wire to a voltmeter and a lithium ion battery to form a circuit, the protection circuit board was immersed in ionic drinking water, Pocari Sweat (trade name, manufactured by Otsuka Pharmaceutical Co., Ltd.) for one hour. The voltage change before and after the immersion was measured, but no change was observed at 4.2 V in any case. (Comparative Example 1) The same Pocari Sweat immersion test as in Example 1 was performed using the same protective circuit board for a lithium ion secondary battery with lead wires except that the treatment with the photosensitive resin composition was not performed. The voltage which was 4.2 V is immersion 10
After 2 seconds, the voltage dropped to 1.7V. (Examples 2 to 4) In the same manner as in Example 1 except that the amount of ultraviolet irradiation was changed using a photosensitive resin composition obtained by using an unsaturated polyurethane (A) and variously changing the composition of an ethylenically unsaturated compound and the like. The treatment to the protection circuit board for the lithium ion secondary battery with the lead wire and the Pocari Sweat immersion test were performed. The composition is shown in Table 1 and the test results are shown in Table 2.

[0033]

[Table 1]

[0034]

[Table 2]

Example 5 680 g of polycaprolactone diol having an average molecular weight of 500 determined from the hydroxyl value, and polypropylene glycol 450 having an average molecular weight of 950
g and tolylene diisocyanate (371 g) were reacted to obtain a polyurethane having isocyanate groups at both ends. Further, 2-hydroxypropyl methacrylate 345
g, and the reaction is carried out.
As a result, an unsaturated polyurethane (B) having a number average molecular weight of 5,800 in terms of polystyrene measured by C was obtained. 116 g of the above unsaturated polyurethane (B) (containing 16 g of excess 2-hydroxypropyl methacrylate as a diluent monomer), 100 g of pentaerythritol triacrylate, 100 g of isobornyl acrylate, 150 g of tetraethylene glycol diacrylate, 50 g of diethylaminoethyl methacrylate, α 20 g of -methoxybenzoin methyl ether, 5 g of benzophenone and 0.5 g of 2,6-di-t-butyl-p-cresol were mixed to obtain a photosensitive resin composition having a viscosity of 2 poise at 20 ° C.

A protective circuit board for a lithium ion secondary battery with a lead wire is immersed in the photosensitive resin composition and then pulled up, and ultraviolet rays having a intensity of 4 mW / cm ² from a 40 W ultraviolet fluorescent lamp having a central wavelength of 370 nm. And ² mW / cm ² of ultraviolet light from a 20 W germicidal lamp having a center wavelength of 254 nm, by arranging these lamps alternately and simultaneously irradiating them from one side of the protection circuit board. Irradiation for 1 minute and then for 1 minute from the opposite side resulted in a tack-free cured film on the protection circuit board. The film adhered firmly to the substrate.

The protection circuit base is a lithium ion battery,
After forming a voltmeter and a circuit, the circuit was immersed in an electrolyte for a lithium ion battery for 1 hour, and a voltage change before and after the immersion was examined.
The voltage, which was 4.2 V before immersion, is maintained at 4.2 V even after immersion, and is sufficient to protect the protection circuit board and maintain its function even if the electrolyte leaks from the battery. It was confirmed that the material was a protective coating material. (Example 6 and Comparative Example 2) 300 g of poly-1,4-butylene glycol adipate diol having an average molecular weight of 510 determined from the hydroxyl value, 52.5 g of polypropylene glycol having an average molecular weight of 960, and 173 g of tolylene diisocyanate were reacted at both ends. A polymer having an isocyanate group was obtained. Next, 303 g of 2-hydroxypropyl methacrylate was added to react with the isocyanate group of the polymer, and G having methacrylate groups at both ends was added.
Polystyrene-equivalent number average molecular weight 230 determined by PC specification
0 unsaturated polyurethane (C) was obtained.

124 g of this unsaturated polyurethane (C) (including 24 g of excess 2-hydroxypropyl methacrylate as a diluent monomer), 62.5 g of 2-hydroxyethyl methacrylate, 12.5 g of pentaerythritol triacrylate, and the average determined from the hydroxyl value Diacrylate 50 of polyethylene glycol having a molecular weight of 400
g, 10 g of α-methoxybenzoin methyl ether, 2 g of benzophenone, and 0.3 g of 2,6-di-t-butyl-p-cresol were mixed to obtain a photosensitive resin composition.

A protective circuit board for a lithium ion battery with a lead wire was applied and cured in the same manner as in Example 5, and an immersion test in an electrolytic solution was performed. It was confirmed that the voltage was 2 V and the electrolyte had resistance. For comparison, an immersion test in an electrolytic solution was performed using a protection circuit board not covered with a photosensitive resin, and a voltage drop to about 1.2 V occurred immediately after the immersion.

(Embodiment 7) The photosensitive resin 100 of Embodiment 6
Silica (trade name Cycilia 470, manufactured by Fuji Silysia Chemical Ltd.) 1 having an average particle diameter of 12 μm and an average pore diameter of 0.017 μm by a Coulter counter method having a hydroxyl group in g
0 g was added and mixed to obtain a photosensitive resin composition. When the composition was applied and cured on a protective circuit board for a lithium ion battery with lead wires in the same manner as in Example 5, a cured film having no tackiness was obtained. Next, an immersion test in an electrolytic solution composed of ethylene carbonate / lithium hexafluorophosphate was performed. Even after 6 days, the same voltage of 4.2 V as before the immersion was exhibited, and high resistance to the electrolytic solution was confirmed. When the photosensitive resin of Example 6 was used, the voltage did not decrease after immersion for 6 hours, but the voltage decreased after immersion for 24 hours. (Examples 8 to 10 and Comparative Example 3) A photosensitive resin composition was prepared in the same manner as in Example 7 except that the silica used in the photosensitive resin composition of Example 7 was replaced with one having various characteristics. The electrolyte resistance was examined.

[0041]

[Table 3] Note 1: Psychia 350, 770, 1510, 6020
Are the trade names of silica manufactured by Fuji Silysia Chemical Ltd. The protective circuits coated with the photosensitive resin compositions of Examples 8, 9, and 10 did not cause a voltage drop due to immersion for 6 days. The coating of the photosensitive resin of No. 11 is the same as that of the coating of the photosensitive resin of Example 6 which is used as a blank.
The voltage dropped during time immersion. For this reason, it was found that silica having no hydroxyl group by treatment had no adverse effect, but had no effect of improving the resistance to electrolytic solution.

[0042]

The electronic circuit is coated with the photosensitive resin composition of the present invention and cured, so that even if the electronic circuit comes into contact with a leaked electrolytic solution, spilled water, ionic drinking water, or the like, the electronic circuit can be used. Function can be prevented from being abnormal.

Claims (2)

[Claims] 1. An unsaturated polyurethane having an ethylenically unsaturated bond in the molecule and having a number average molecular weight in terms of polystyrene of from 800 to 13,000 based on GPC measurement, an ethylenically unsaturated compound having a molecular weight of less than 800 and having an ethylenically unsaturated bond, And a photopolymerization initiator as an essential component. A photosensitive resin composition for coating an electronic circuit. 2. The composition according to claim 1, further comprising a filler having a hydroxyl group in addition to the above components.
The photosensitive resin composition for coating an electronic circuit according to the above.