JP3928136B2 - Solder resist paint, cured product thereof and printed wiring board provided with coating - Google Patents

Description

  The present invention relates to a two-component type solder resist paint, a cured product thereof, and a printed wiring board provided with a film which is one form of the cured product. More specifically, in a two-component type solder resist coating composed of a first liquid containing a partial hydrolyzate of an alkoxysilane compound and a second liquid containing alkoxy titanium, the first liquid and / or the second liquid A two-part type solder resist paint containing potassium titanate fiber, a cured product formed from these two-part type solder resist paints, and a coating that is one form of a cured product formed from the solder resist paint The present invention relates to a printed wiring board. The cured product and the coating have high heat resistance to withstand component mounting with lead-free solder. Furthermore, although it does not contain an antimony compound, a halogen compound and a phosphorus compound, it also exhibits flame retardancy.

  At present, alkali developing type liquid solder resists are widely used as solder resists for some consumer printed wiring boards and most industrial printed wiring boards. As an alkali development type liquid solder resist comprising such a photosensitive / thermosetting resin composition, JP-A-61-2243869, JP-A-3-253093, JP-A-4-281454, A composition is disclosed in Japanese Laid-Open Patent Application No. 8-335767.

  In addition, when flame retardancy is imparted to the solder resist, halogen flame retardants and combinations of halogen flame retardants and antimony compounds are widely used. As an alkali development type solder resist using such a halogen flame retardant, a composition is disclosed in, for example, Japanese Patent Application Laid-Open No. 2-88615. However, recently, demands for dehalogenation and deantimony for flame retardancy have increased due to global environmental problems and safety problems for human bodies. For example, JP-A-2003-277470 discloses a halogen compound. A composition containing an unused organophosphorus compound is disclosed.

  On the other hand, apart from the alkali developing type liquid solder resist, a thermosetting type liquid solder resist has been used as another solder resist for a long time. Japanese Patent Publication Nos. 57-49588 and 56-15741. JP-B-5-75032 and JP-A-11-158252 disclose the composition. As the composition, an epoxy resin is mainly used. Recently, liquid solder resists for thermosetting are mainly used for flexible printed wiring boards and IC package printed wiring boards.

  By the way, various electronic components are mounted on the printed wiring board, and most of them are joined by solder. This solder is also being switched from the tin-lead eutectic solder to the lead-free solder due to environmental problems, and a higher soldering temperature is required. As a result, the heat resistance of the solder resist must be improved. Is no longer. For the purpose of improving the heat resistance, a method of adding a filler having a radius of several tens nm to several μm to the solder resist has been proposed, but it is insufficient in terms of quality and productivity. Thus, in order to solve environmental problems, solder resists that do not contain halogen compounds, phosphorus compounds, and antimony compounds and have high heat resistance that can withstand component mounting with lead-free solder have not been put into practical use. Is the current situation.

  Regardless of whether it is an alkali development type or a thermosetting type, conventional solder resists have a limit in heat resistance and flame retardancy because organic polymers are mainstream. In many cases, after a solder resist is applied to the entire surface of the substrate, a coating is formed on the substrate or the like through complicated operations such as drying, exposure, development, and curing. And there are very few cases where a solder resist is applied only to a necessary portion according to a pattern, and then a film is formed only by a thermosetting operation. Furthermore, as described above, organic solder resists are mainstream, and inorganic solder resists are very few. If an inorganic solder resist appears, it has a feature that it can withstand high temperatures during soldering, and can form a solder resist film with high heat resistance, and in particular, halogen compounds, antimony compounds, Even if a flame retardant such as a phosphorus compound is not used, an effect of ensuring flame retardancy can be expected. In addition, a solder resist of a type in which a solder resist is applied only to a necessary portion according to a pattern and then a film is formed only by a thermosetting operation, no equipment for exposure and development is required, and the number of processes is small. This is also advantageous from the viewpoint of manufacturing cost.

  While the inventors have studied a coating agent having excellent heat resistance, a composition comprising an alkoxy compound, alkoxy titanium, an aqueous dispersion of colloidal silica, silica powder, and the like forms a film having excellent heat resistance. And applied for a patent as a composition and a film excellent in heat dissipation and heat shielding properties (Japanese Patent Application No. 2003-159589 (Patent Document 1)). The present inventor has been studying solder resist paints by paying attention to the application of such a composition having excellent heat dissipation and heat shielding properties to a solder resist.

  As an application of an alkoxysilane compound to a solder resist composition, it is obtained by partially subjecting a novolak phenol resin and an alkoxysilane partial condensate to a dealcoholization condensation reaction in Japanese Patent Application Laid-Open No. 2001-40663 (Patent Document 2). It is described that an alkoxy group-containing silane-modified phenol resin is used together with an epoxy resin. However, this alkoxy group-containing silane-modified phenolic resin has a problem that it is necessary to strictly control the degree of condensation of alkoxysilane and the degree of condensation due to dealcoholization, and its production becomes complicated. Since the composition is based on an epoxy resin, the cured film is likely to be warped or cracked, and has a limited heat resistance.

  It has already been known that an inorganic coating agent can be obtained by reacting a partially hydrolyzed silane compound with alkoxytitanium (Japanese Patent Laid-Open No. 63-12671 (Patent Document 3)). And it is described in patent document 3 that the compound which put the silica fine powder into the inorganic type coating agent is used for the tile joint material and the filling cement. However, when these mixtures are used for solder resists, as shown in the comparative examples, the hardness of the coating is low and a good coating cannot be obtained.

: Japanese Patent Application No. 2003-159589 : JP 2001-40663 A : JP-A 63-12671

  The present invention has been made in view of the circumstances relating to the above-mentioned organic solder resist, and pays attention to the inorganic solder resist, has high heat resistance, and therefore can withstand high temperature mounting by lead-free solder when mounting components. Inorganic solder resist paint, which has high flame retardancy without using a flame retardant, and has a simplified process and reduced cost in comparison with conventional ones, An object of the present invention is to provide a cured product made of a solder resist paint and a printed wiring board provided with a film made of the solder resist paint.

  The gist of the present invention is that a first liquid composed of a partial hydrolyzate of an alkoxysilane compound and an organic solvent and a first liquid composed of a second liquid composed of alkoxytitanium and an organic solvent are mixed and cured. In the two-component type solder resist coating, the first component and / or the second component contains potassium titanate fibers.

  The first liquid and / or the second liquid can contain at least one selected from the group consisting of kaolin powder, alumina powder, and coupling agent-treated aluminum hydroxide powder, and the first liquid and / or The second liquid can contain a fumed silica powder that has been subjected to a surface hydrophobization treatment, the first liquid and / or the second liquid can also contain an ethylcellulose powder, the first liquid and / or A blue pigment containing no halogen atom and / or a yellow pigment containing no halogen atom can be added to the second liquid.

  A solder resist cured product can be obtained by mixing the above-described first and second liquids of the solder resist paint. Furthermore, a film which is one form of the cured product can be obtained in the same manner. This coating can be patterned on a printed wiring board. At this time, the thickness of the coating is preferably 7 μm to 40 μm at the edge of the circuit.

  The inventor has intensively researched and completed the present invention, paying attention to the heat resistance, flame retardancy, etc. of an inorganic polymer obtained by the reaction of a partially hydrolyzed product of an alkoxysilane compound and alkoxytitanium. . That is, potassium titanate fiber is added to the partially hydrolyzed product of alkoxysilane compound, and kaolin powder, alumina powder, coupling agent-treated aluminum hydroxide powder, pigment, etc. are added as necessary, and surface hydrophobicity is further added. It is a form of solder resist paint with excellent performance, cured product made of the paint, and cured product made of the paint by adding fumed silica powder or ethyl cellulose powder that has been subjected to a chemical treatment and reacting with alkoxy titanium. A printed wiring board provided with a coating is provided. At this time, potassium titanate fiber, kaolin powder, alumina powder, aluminum hydroxide powder treated with a coupling agent, fumed silica powder and ethyl cellulose powder subjected to surface hydrophobization treatment, pigment, etc. are contained in a liquid containing alkoxy titanium. It can also be mixed, and can also be mixed with both the liquid containing the partial hydrolyzate of an alkoxysilane compound, and the liquid containing an alkoxy titanium.

  The solder resist paint of the present invention forms a hardened solder resist and a film, but these hardened and coated films have high heat resistance and lead for solder used when various electronic components are mounted on a printed wiring board. It exhibits high heat resistance that can withstand the increased mounting temperature associated with the free operation, and has a great practical advantage. In addition, since it is substantially free of antimony, halogen and phosphorus, compared to conventional compositions, the burden associated with the disposal of printed wiring boards without adversely affecting the human body or the natural environment due to incineration of waste. Can be reduced. In addition, the solder resist coating is easy to manufacture, and the cured product and film formation do not require complicated equipment, the process is simplified, and the manufacturing cost is low.

  The basis of the present invention is that a first liquid composed of a partial hydrolyzate of an alkoxysilane compound and an organic solvent and a first liquid composed of a second liquid composed of an alkoxy titanium and an organic solvent are mixed with the second liquid. In the two-component type solder resist paint to be cured, the first solution and / or the second solution is a two-component type solder resist paint containing potassium titanate fibers and the like. The first liquid and the second liquid are mixed, and the mixed liquid (this mixed liquid is referred to as a solder resist liquid) is applied to the coated body, for example, and heated as necessary, so that it is inorganic on the coated body. Form a cured product of the system. When applied in the form of a film, a film is formed. Here, the potassium titanate fiber can be added to the first liquid, and can also be added to the second liquid. It can also be added to both the first liquid and the second liquid. In addition to potassium titanate fiber, the first liquid and / or the second liquid include kaolin powder, alumina powder, coupling agent-treated aluminum hydroxide powder, and fumed silica powder and ethyl cellulose subjected to surface hydrophobization treatment. Powders, pigments, and the like can be added as appropriate. Hereinafter, the present invention will be mainly described by mixing potassium titanate fibers and the like into the first liquid containing the partial hydrolyzate of alkoxysilane compound. However, potassium titanate fibers, kaolin powder, alumina powder, coupling The agent-treated aluminum hydroxide powder, fumed silica powder, ethyl cellulose powder, pigments and the like subjected to surface hydrophobization treatment can also be used by mixing with a second liquid containing alkoxy titanium. In addition, kaolin powder, alumina powder, coupling agent-treated aluminum hydroxide powder, surface hydrophobized fumed silica powder, ethyl cellulose powder, pigments, etc. may be used separately in the first and second liquids. it can.

  For example, potassium titanate fiber is added to the first liquid, kaolin powder, alumina powder, coupling agent-treated aluminum hydroxide powder is added to the second liquid, and fumed silica powder or ethyl cellulose powder subjected to surface hydrophobization treatment, Pigment etc. may be added, potassium titanate fiber, kaolin powder, alumina powder, coupling agent treated aluminum hydroxide powder, pigment etc. are added to the first liquid, and surface hydrophobic treatment is applied to the second liquid Fumed silica powder or ethyl cellulose powder may be added, potassium titanate fiber is added to the second liquid, and kaolin powder, alumina powder, coupling agent treated water is added to the first liquid in addition to the potassium titanate fiber. Add aluminum oxide powder, fumed silica powder with hydrophobized surface, ethyl cellulose powder, pigment, etc. It is also possible to add potassium titanate fiber, kaolin powder, alumina powder, coupling agent-treated aluminum hydroxide powder, etc. to the second liquid, and to the first liquid in addition to the potassium titanate fiber to make the surface hydrophobic. Dosilica powder, ethyl cellulose powder, pigments and the like may be added. In addition, kaolin powder, alumina powder, aluminum hydroxide powder treated with coupling agent, fumed silica powder with surface hydrophobic treatment, ethyl cellulose powder, pigment, etc. are added separately in the first and second liquids For example, 80% of these minerals to be added can be added to the first liquid and the remaining 20% can be added to the second liquid. In any case, a predetermined amount of potassium titanate fiber, kaolin powder, alumina powder, coupling agent-treated aluminum hydroxide powder, and surface hydrophobization treatment were performed in a solder resist solution obtained by mixing the first solution and the second solution. It only has to contain fumed silica powder, ethyl cellulose powder, pigment, or the like.

  Alkoxy titanium may be used alone, but diluted with an organic solvent. That is, the second liquid is used in a state where at least alkoxy titanium and an organic solvent are mixed. In order to uniformly mix with the first liquid, potassium titanate fiber, kaolin powder, alumina powder, coupling agent-treated aluminum hydroxide powder, and fumed silica that has been surface-hydrophobized. It is also preferable for uniformly mixing powder, ethylcellulose powder, pigment and the like. As the organic solvent for alkoxy titanium, any organic solvent may be used as long as it can stably hold alkoxy titanium. Needless to say, the same solvent as the organic solvent of the first liquid can be used.

  The partial hydrolyzate of the alkoxysilane compound of the first solution and the alkoxytitanium of the second solution start to react immediately when they are mixed. Therefore, the solder resist paint should be used after mixing well immediately before use. Is good. And after mixing the 1st liquid and the 2nd liquid, it is recommended not to leave it in the state which used up and mixed for a long time. Moreover, after mixing the first liquid and the second liquid, it is preferable to keep the temperature as low as possible without exposing it to a high temperature.

  When the first liquid and the second liquid are mixed, the partially hydrolyzed product of the alkoxysilane compound and the alkoxytitanium react to be cured. This is because when a partially hydrolyzed product of an alkoxysilane compound reacts with an alkoxytitanium, dealcoholization occurs to form a Si—O—Ti bond or a Si—O—Si bond, resulting in a three-dimensional network structure polymer. Because it becomes. The formed polymer, that is, the cured product or film is substantially composed of an inorganic substance. The cured product or film is composed of inorganic material by 80% or more by weight. The organic group in the solder resist paint of the present invention is an organic group such as an alkoxy group (alcohol component) bonded to a silicon atom and a titanium atom and an alkyl group bonded directly to a silicon atom. When the partial hydrolyzate of the silane compound reacts with the alkoxytitanium, a Si—O—Ti bond or a Si—O—Si bond is generated, and the alcohol component of the alkoxy group is eliminated. However, an organic group such as an alkyl group directly bonded to the silicon atom remains as it is.

  The first liquid and / or the second liquid of the solder resist paint of the present invention are mixed with potassium titanate fiber. The reason for using this is described below. A printed wiring board consists of a circuit part and a board | substrate part, and the unevenness | corrugation of the surface is a level | step difference of 30-100 micrometers generally. Therefore, the solder resist for circuit coating needs to have a thickness of 20 to 80 μm at the concave portion and 10 to 30 μm at the convex portion. Also, since electronic components are mounted on the printed wiring board, the solder resist needs to withstand solder at 260 ° C., for example. It is difficult to form a thick film only with a cured product composed of a partially hydrolyzed product of an alkoxysilane compound and an alkoxytitanium, and cracks are likely to occur with, for example, 260 ° C. solder. By adding potassium titanate fibers to these paints, the thickness of the coating can be secured, and for example, a coating that can withstand solder at 260 ° C. can be formed.

  Moreover, at least 1 type selected from the group which consists of kaolin powder, an alumina powder, and a coupling agent process aluminum hydroxide powder other than a potassium titanate fiber can be added to a 1st liquid and / or a 2nd liquid. By adding these compounds, a thick film can be formed on the uneven surface of the coated body, and there is an effect that a film without unevenness can be formed. On the other hand, when the partially hydrolyzed silane compound and alkoxytitanium are reacted, mixing of silica powder is described in Patent Document 3 (Japanese Patent Laid-Open No. 63-12671). Although various studies were made including various coupling agent-treated silica powders, it was impossible to obtain a cured product or film that had extremely low pencil hardness after thermosetting and could be put to practical use.

  In addition, the addition of hydrophobized fumed silica powder to the first liquid and / or the second liquid can increase the viscosity of the solder resist liquid after mixing with the first liquid and the second liquid. Further, it is possible to improve the printability of screen printing or flexographic printing of a solder resist solution. Moreover, the effect of preventing sedimentation of potassium titanate fibers contained in the first liquid and / or the second liquid, and further kaolin powder, alumina powder, coupling agent-treated aluminum hydroxide and the like was recognized. Furthermore, by adding ethyl cellulose powder to these paints, it is possible to improve the external punching ability from the work board during the manufacturing process of the printed wiring board.

  The blending ratio of the organic solvent constituting the solder resist paint, that is, the solder resist liquid obtained by mixing the first liquid and the second liquid will be described below. The amount of the organic solvent in the solder resist solution obtained by mixing the first solution and the second solution is not particularly limited, but is very small, for example, 30% or less by weight based on the total amount of the solder resist solution. If it becomes, the hardening time of the liquid mixture at the time of mixing a 1st liquid and a 2nd liquid will become short, and it is unpreferable on use. Also, if the amount is very large, for example, 55% or more by weight with respect to the total amount of the solder resist solution, the coating becomes thin and it becomes difficult to form a stable coating.

  The potassium titanate fiber is preferably used in an amount of 18 to 80 parts by weight with respect to 100 parts by weight of the partially hydrolyzed alkoxysilane compound. A good film can be obtained with the addition amount in this range. If it is less than 18 parts by weight, it is difficult to ensure the thickness of the coating, and for example, resistance to soldering at 260 ° C. becomes poor. On the other hand, when it exceeds 80 parts by weight, for example, when a film is formed by screen printing, the printability is deteriorated, and it is difficult to obtain a uniform and non-uniform film, which is not preferable in practice.

  The amount of alkoxytitanium used as the main component of the second liquid is 5 to 30 parts by weight with respect to 100 parts by weight of the partially hydrolyzed alkoxysilane compound, so that good film performance can be obtained. it can. If it is less than 5 parts by weight, the pencil hardness etc. of the coating will be low and it will not be practical, and if it exceeds 30 parts by weight, for example, it will be easy to crack in the coating in a float test in a solder bath at 260 ° C. It will not be. The amount used here is based on alkoxytitanium, a partially hydrolyzed alkoxysilane compound that does not contain an organic solvent. The actual amount of alkoxytitanium added depends on the type of alkoxytitanium compound used (for example, titanium tetrabutoxide or titanium tetrapropoxide), the type of alkoxysilane compound and the amount used (especially trialkoxysilane) And the amount of tetraalkoxysilane used). If the amount of trialkoxysilane or tetraalkoxysilane used is large among the alkoxysilanes, the amount of alkoxytitanium added may be small. In addition, since titanium tetrabutoxide has a large molecular weight, it is added in a larger amount than titanium tetrapropoxide.

  The amount of alkoxytitanium added is preferably in the range of 0.010 to 0.15, expressed as the ratio of titanium element to silicon element. When the addition amount of titanium is less than 0.010 with respect to silicon element, it becomes difficult to form a cured product having a network structure and a coating, while when the addition amount of titanium is more than 0.15 with respect to silicon element, The curing rate of the solder resist solution is too high, or the performance of the formed cured product or film is not sufficient, for example, cracks are likely to occur during soldering.

  Next, the addition amount of kaolin powder, alumina powder, coupling agent-treated aluminum hydroxide powder, etc., but the upper limit of the addition amount does not cause film choking (a phenomenon in which the powder is exposed on the film surface). Range may be sufficient.

  The fumed silica powder subjected to the surface hydrophobization treatment is preferably 19 parts by weight or less with respect to 100 parts by weight of the partially hydrolyzed alkoxysilane compound. If this amount is exceeded, the viscosity increase during storage of the mixed liquid mixed with the second liquid is accelerated, and small-diameter grains are likely to be generated in the coating film, which is not practically preferable. The ethyl cellulose powder is preferably 13 parts by weight or less with respect to 100 parts by weight of the partially hydrolyzed product of the alkoxysilane compound. This is because if the amount exceeds this amount, the flame retardancy of the coating will decrease, and as for the pigment, a blue pigment containing no halogen atom and a yellow pigment containing no halogen atom are used. The ratio of blue pigment and yellow pigment in the amount of green can be used.

Next, the partial hydrolyzate of the alkoxysilane compound, which is the central component of the solder resist paint of the present invention, will be described. The partially hydrolyzed product of the alkoxysilane compound is an oligomer obtained by partially hydrolyzing and condensing the alkoxysilane compound represented by the general formula 1. Examples of R 1 in Chemical Formula ¹ include a methyl group, an ethyl group, a propyl group, an isopropyl group, an aminoethyl group, a glycidylpropyl group (see Chemical Formula 2), and examples of R ² include a methyl group and an ethyl group. be able to. Here, n is an integer of 0-3.

  As the alkoxysilane compound, at least one selected from the substances represented by Chemical Formula 1 is appropriately used. Usually, two to three compounds are mixed and used. A partial hydrolyzate can be obtained by reacting these alkoxysilane compounds with an amount of water smaller than the amount of water (calculated value) required to completely hydrolyze the alkoxysilane in the presence of an acid catalyst. . When trialkoxysilane or tetraalkoxysilane is present, the coating obtained by curing the coating has a three-dimensional structure.

  As the organic solvent used in the first liquid or the second liquid, the following solvents can be used. Methyl alcohol, ethyl alcohol, isopropyl alcohol, 1-butanol, 2-butanol, diacetone alcohol, butyl acetate, butyl butyrate, propylene glycol monomethyl ether, diacetone alcohol, butyl carbitol, butyl carbitol acetate, butyl lactate, ethyl Carbitol, ethyl carbitol acetate, isophorone, dipropylene glycol methyl ether, dipropylene glycol n-propyl ether, propylene glycol n-butyl ether, dipropylene glycol dimethyl ether, propylene glycol diacetate, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate , Solvents such as 3-methoxybutanol and 3-methoxybutyl acetate A. However, it is not limited to these solvents, and the solvent can be used alone or in combination of two or more.

  Potassium titanate fiber is a potassium hexatitanate fiber. The fiber diameter is preferably 1 μm or less, the average fiber length is preferably 20 μm or less, and the maximum length is preferably 100 μm or less. If the diameter, average length, and maximum length of the fiber are larger than these values, the coating becomes uneven during screen printing or flexographic printing, and stable printing cannot be performed, making it unsuitable.

  Alkoxytitanium is represented by Formula 3. Examples of R in the formula include a methyl group, an ethyl group, a propyl group, and a butyl group. From the reaction rate, those having a propyl group or a butyl group can be suitably used as R.

The kaolin powder is preferably a powder having an average particle size of 5 μm or less and a maximum particle size of 25 μm or less, and a moisture content of 0.8% by weight or less. If the particle size is larger than these values, spots are likely to occur on the film, and it is not suitable because it becomes less uniform. If the adhering moisture exceeds 0.8% by weight, the pencil hardness of the coating becomes extremely small, which is not suitable. The alumina powder preferably has an average particle size of 5 μm or less and a maximum particle size of 25 μm or less, and a powder having a sodium oxide (Na ₂ O) content of 0.06 wt% or less can be suitably used. If the particle size is larger than these values, spots are likely to occur on the film, and a uniform film cannot be obtained, which is not suitable. If the amount of sodium oxide (Na ₂ O) exceeds 0.06% by weight, curing of the solder resist solution is inhibited, which is not suitable.

The coupling agent-treated aluminum hydroxide powder preferably has an average particle size of 3 μm or less and a maximum particle size of 25 μm or less, and soluble sodium oxide preferably has a content of 0.06% by weight or less. Furthermore, those whose surface is coated with an epoxysilane or titanate coupling agent can be suitably used. What was surface-coated with an epoxysilane coupling agent is excellent in adhesion to printed circuit board copper. The limitation of numerical values for particle size and soluble sodium oxide (Na ₂ O) is the same reason as for alumina powder. In addition, if the surface is not coated with a coupling treatment agent, the coating film will shed and is not suitable.

  The fumed silica powder subjected to surface hydrophobization treatment preferably has an average primary particle diameter of 20 nm or less. Those whose surfaces have been subjected to hydrophobic treatment with dimethyldichlorosilane, hexamethyldisilazane, or the like can be suitably used. In particular, the hexamethyldisilazane-treated product is effective in increasing the viscosity of the solder resist solution (the mixed solution of the first solution and the second solution is called the solder resist solution). If the surface is not hydrophobized, it is not suitable because there is no thickening effect of the solder resist solution. On the other hand, if the average diameter of the primary particles exceeds 20 nm, circular protrusions are generated on the cured film, which is not preferable. As the ethylcellulose powder, for example, N-type (having an ethoxy group substitution degree of 2.41 to 2.51 per unit of anhydrous glucose) manufactured by Hercules, USA can be suitably used. Among the N-types, N-50 and N-100 are particularly preferable from the viewpoint of the balance between solubility and coating quality in the grades classified by viscosity. As for the blue pigment containing no halogen atom and the yellow pigment containing no halogen atom, examples of the blue pigment include copper phthalocyanine blue, iron phthalocyanine blue, and indigo. As the yellow pigment, anthraquinone yellow, benzimidazolone yellow, iron oxide and the like can be suitably used.

  Next, a procedure for preparing a solder resist solution by mixing the first solution and the second solution and applying the solder resist solution to a printed wiring board or the like to form a cured product or film will be described. Potassium titanate fiber is added to an organic solvent in which a partial hydrolyzate of an alkoxysilane compound is dissolved and mixed. If necessary, kaolin powder, alumina powder, coupling agent-treated aluminum hydroxide powder, surface-hydrophobized fumed silica powder, ethyl cellulose powder, and blue pigment and halogen atoms that do not contain halogen atoms. A yellow pigment not contained is added, and the mixture is stirred and mixed in a stirring tank having a propeller-type or saddle-type rotary blade until these fibers and powder are sufficiently kneaded into the liquid. Of course, a stirring method other than this method can also be used. The mixing temperature at this time is preferably 40 ° C. or less. When the temperature exceeds 40 ° C., it is not preferable because the mixed solution is likely to be covered with a thin film (thin film formed on the surface of the solder resist solution). Further, if necessary, the mixed solution is transferred to a ball mill, a three-roller or the like, and mixed and kneaded until the powder and fibers are sufficiently dispersed. At this time, the liquid temperature during mixing and kneading is preferably 40 ° C. or lower for the same reason as described above. In this way, the first liquid is obtained.

  On the other hand, a second liquid in which alkoxy titanium is dissolved in an organic solvent is prepared. The first liquid and the second liquid are generally stirred for 10 minutes or more in a stirring tank having a propeller type or saddle type rotary blade until both liquids are sufficiently mixed. The stirring liquid temperature at this time is preferably 30 ° C. or less. If it exceeds 30 ° C., uneven spots and the like are generated on the appearance of the film, which is not preferable.

  In preparing the solder resist solution, it is preferable that the viscosities of the first liquid and the second liquid are substantially equal to each other immediately before mixing. In addition, when preparing a solder resist solution, potassium titanate fiber, kaolin powder, alumina added to the organic solvent solution of the partial hydrolyzate of alkoxysilane compound to prevent the progress of local reaction due to insufficient mixing Part of powder, coupling agent-treated aluminum hydroxide powder, surface-hydrophobized fumed silica powder, ethyl cellulose powder, pigment, etc. are added to an organic solvent solution of alkoxy titanium, and mixed well with a ball mill or three rolls. You may knead. In this case, the liquid temperature during mixing and kneading is preferably 40 ° C. or lower for the same reason as described above. Also, when the first liquid and the second liquid are mixed, they immediately react and begin to cure, so after mixing the first liquid and the second liquid, it can be quickly applied to the object without leaving for a long time. Is good. Also, it is preferable to use up the solder resist solution obtained by mixing the first solution and the second solution without leaving them. If the solder resist solution remains, it is recommended that it be discarded and not reused. The solder resist solution can be obtained by preparing the first solution and the second solution separately, and mixing the two. Alternatively, the potassium titanate fiber is added to the organic solvent solution of the partially hydrolyzed alkoxysilane compound. Also, by mixing kaolin powder, alumina powder, coupling agent-treated aluminum hydroxide powder, surface hydrophobized fumed silica powder, ethyl cellulose powder, pigment, etc., and then mixing an organic solvent solution of alkoxy titanium It can also be obtained.

  In order to form a film on the substrate, a solder resist solution, which is a mixed solution of the first solution and the second solution prepared above, is applied to the substrate, dried and heat-treated. The substrate is a printed wiring board in which a circuit is formed by a subtractive method, a semi-additive method, an additive method, or the like. As a method of applying a solder resist solution on the surface of the printed wiring board to form a pattern, a screen printing method or a flexographic printing method can be applied.

  Drying and curing of the coating applied to the circuit surface is performed by drying and curing with a profile in which the temperature is gradually raised from room temperature in the range of 200 ° C. at the maximum and 100 ° C. at the minimum. Cooling to room temperature after curing is performed with a profile that gradually cools, avoiding rapid cooling. The temperature rise and cooling profiles are determined in consideration of quality and productivity depending on the thickness of the printed wiring board substrate and the circuit thickness. When the maximum temperature exceeds 200 ° C., it is not preferable due to thermal deterioration of the printed wiring board and generation of internal stress. Moreover, when the maximum temperature is less than 100 ° C., the curing (drying) of the solder resist coating of the present invention does not end in a practically necessary time, which is not preferable.

  The film thickness after curing needs to be 7 μm or more at the edge of the circuit on the printed wiring board. If it is less than 7 μm, the protection of the circuit is deteriorated during long-term use, which is not preferable.

  An alkoxysilane mixture composed of 2000 g of dimethyldimethoxysilane, 4000 g of methyltrimethoxysilane and 1000 g of an alkoxysilane containing an epoxy group represented by formula 4 (see formula 4) is dropped into a mixture of 1000 g of pure water and 100 g of acetic acid. And reacted at room temperature. The reaction proceeded with exotherm and was completed in tens of minutes. To this was added propylene glycol monomethyl ether to obtain a hydrolyzate solution of an alkoxysilane compound. The amount of propylene glycol monomethyl ether added was 45% by weight based on the solid content after the alkoxysilane compound hydrolyzate solution was dried at 105 ° C. for 120 minutes.

  Next, 240 g of potassium hexatitanate fibers (fibers having an average diameter of 0.5 μm and an average length of 15 μm) are added to 1000 g of the partially hydrolyzed alkoxysilane compound solution, and the liquid temperature is 20 ° C. To 30 ° C. for 30 minutes in a stirring tank having a propeller rotor. Next, this mixed solution was transferred to a ball mill and mixed for 120 minutes. The liquid temperature at the time of mixing was controlled to be 20 ° C to 30 ° C. Defoaming was easy during the ball mill. In this way, a first liquid was prepared. As a second liquid, a 50 wt% solution of propylene glycol monomethyl ether of tetrabutoxytitanium was prepared. The second liquid is added to the first liquid at a ratio of 36 parts by weight with respect to 100 parts by weight of the solid after the hydrolyzate solution of the alkoxysilane compound is dried at 105 ° C. for 120 minutes. Mixing was performed at 25 ° C. for 15 minutes to obtain a liquid solder resist solution.

  1000 g of the partially hydrolyzed product of the alkoxysilane compound of Example 1 and 100 g of kaolin powder (with an average particle size of the powder of 3.0 μm and an attached moisture of 0.6% by weight) and alumina powder (average of the powder) 460 g with a particle size of 2.0 μm and sodium oxide of 0.03% by weight) and 120 g of potassium hexatitanate fiber (with an average fiber diameter of 0.5 μm and an average length of 15 μm) The mixture was stirred at a liquid temperature of 20 ° C. to 30 ° C. for 30 minutes in a stirring tank having a propeller rotor. Next, this mixed solution was transferred to a ball mill and mixed for 120 minutes. The liquid temperature at the time of mixing was controlled to be 20 ° C to 30 ° C. Defoaming was easy during the ball mill. In this way, the first liquid is obtained. As a second liquid, a 50 wt% solution of propylene glycol monomethyl ether of tetrabutoxytitanium was prepared. The second liquid is added to the first liquid at a ratio of 36 parts by weight with respect to 100 parts by weight of the solid after the solution of the partially hydrolyzed alkoxysilane compound is dried at 105 ° C. for 120 minutes. At 25 ° C. for 15 minutes to obtain a liquid solder resist solution.

  Into 1000 g of the partial hydrolyzate solution of the alkoxysilane compound of Example 1, 100 g of kaolin powder (with an average particle size of the powder of 3.0 μm and an attached water content of 0.6% by weight) and alumina powder (of the powder) 460g and potassium hexatitanate fiber (fiber average diameter is 0.5μm, average length is 15μm) 120 g and 50 g of fumed silica powder whose surface has been hydrophobized (the average particle size of the primary particles is 7 nm and surface-treated with hexamethyldisilazane) are added, and the propeller rotor blades at a liquid temperature of 20 ° C. to 30 ° C. for 30 minutes It stirred in the stirring tank which has. Next, this mixed solution was transferred to a ball mill and mixed for 120 minutes. The liquid temperature at the time of mixing was controlled to be 20 ° C to 30 ° C. The first liquid was obtained by simply defoaming during the ball mill. As a second liquid, a 50 wt% solution of propylene glycol monomethyl ether of tetrabutoxytitanium was prepared. The second liquid is added to the first liquid at a ratio of 36 parts by weight with respect to 100 parts by weight of the solid after the hydrolyzate solution of the alkoxysilane compound is dried at 105 ° C. for 120 minutes. Mixing was performed at 25 ° C. for 15 minutes to obtain a liquid solder resist solution.

  Into 1000 g of the partial hydrolyzate solution of the alkoxysilane compound of Example 1, 100 g of kaolin powder (with an average particle size of the powder of 3.0 μm and an attached water content of 0.6% by weight) and alumina powder (of the powder) 460g and potassium hexatitanate fiber (fiber average diameter is 0.5μm, average length is 15μm) Add 120 g and 50 g of fumed silica powder with surface hydrophobization treatment (average particle size of primary particles 7 nm, surface treatment with hexamethyldisilazane) and 30 g of N-50 type ethyl cellulose powder from Hercules, USA The mixture was stirred at a liquid temperature of 20 ° C. to 30 ° C. for 30 minutes in a stirring tank having a propeller-type rotary blade. Next, this mixed solution was transferred to a ball mill and mixed for 120 minutes. The liquid temperature at the time of mixing was controlled to be 20 ° C to 30 ° C. The first liquid was obtained by simply defoaming during the ball mill. As a second liquid, a 50 wt% solution of propylene glycol monomethyl ether of tetrabutoxytitanium was prepared. The second liquid is added to the first liquid at a ratio of 36 parts by weight with respect to 100 parts by weight of the solid after the hydrolyzate solution of the alkoxysilane compound is dried at 105 ° C. for 120 minutes. Mixing was performed at 25 ° C. for 15 minutes to obtain a liquid solder resist solution.

  1000 g of the partially hydrolyzed alkoxysilane compound solution of Example 1, 240 g of potassium hexatitanate fibers (fibers having an average diameter of 0.5 μm and an average length of 15 μm), water treated with a coupling agent 550 g of aluminum oxide powder (powder having an average particle size of 2.3 μm, soluble sodium oxide of 0.05% by weight, and surface-coated with an epoxysilane coupling agent) and surface hydrophobized. 60 g of fumed silica powder (with an average primary particle diameter of 7 nm and surface-treated with hexamethyldisilazane), 4 g of yellow pigment (anthraquinone yellow) and 4 g of blue pigment (copper phthalonic cyan blue) are added, and the liquid temperature The mixture was stirred at 20 to 30 ° C. for 30 minutes in a stirring tank having a propeller rotor. Next, this mixed solution was transferred to a ball mill and mixed for 180 minutes. The liquid temperature at the time of mixing was controlled to be 20 ° C to 30 ° C. In this way, a first liquid was prepared. As a second solution, a 50% by weight solution of tetrabutoxytitanium butyl butyrate was prepared. The second liquid is added to the first liquid at a ratio of 40 parts by weight with respect to 100 parts by weight of the solid after the hydrolyzate solution of the alkoxysilane compound is dried at 105 ° C. for 120 minutes. Mixing was performed at 25 ° C. for 15 minutes to obtain a liquid solder resist solution.

  The solder resist solutions of Examples 1 to 3 were applied to an applicator on the copper foil of an FR-4 grade copper clad laminate patterned by a conventional subtractive method and on the FR-4 grade substrate etched on the entire surface. The temperature was gradually raised with a temperature profile of a maximum temperature of 180 ° C., hot air drying was performed for 120 minutes in the total drying time, and then gradually cooled to room temperature in 60 minutes. For the solder resist solutions of Examples 4 and 5, an applicator was applied on a FR-4 grade copper circuit board patterned by a conventional subtractive method, and gradually increased in a temperature profile of a maximum temperature of 180 ° C. The temperature was raised and hot air drying was performed for 120 minutes in the total drying time, and then gradually cooled to room temperature in 60 minutes. The thickness of the coating after curing (drying) was 10 μm at the edge of the copper circuit.

  About the solder resist hardened | cured material (film) obtained in Examples 1-5, the performance test as a printed wiring board was done. The results are shown in Table 1 for Examples 1, 2, and 3, and Table 2 for Examples 4, 5. The evaluation method for each performance test in the table is as shown separately.

  To 1000 g of the partially hydrolyzed alkoxysilane compound solution of Example 1, 240 g of potassium hexatitanate fibers (fibers having an average diameter of 0.5 μm and an average length of 15 μm) are added, and the liquid temperature is 20 ° C. To 30 ° C. for 30 minutes in a stirring tank having a propeller rotor. Next, this mixed solution was transferred to a ball mill and mixed for 180 minutes. The liquid temperature at the time of mixing was controlled to be 20 ° C to 30 ° C. In this way, a first liquid was obtained. Separately, a 50 wt% solution of tetrabutoxy titanium in propylene glycol monomethyl ether was prepared as the second liquid. The second liquid is used as the first liquid, and 10, 16, 30, 40, 48, 60 weights with respect to 100 parts by weight of the solid after drying the solution of the partially hydrolyzed alkoxysilane compound at 105 ° C. for 120 minutes. The mixture is mixed and mixed at a ratio of parts, mixed at 25 ° C. for 15 minutes with a propeller-type stirrer, and this liquid agent is copper foil of an FR-4 grade copper-clad laminate patterned by a conventional subtractive method The applicator is coated on the FR-4 grade substrate that has been etched on the top and the entire surface. The temperature is gradually raised with a temperature profile of a maximum temperature of 180 ° C., and the whole is dried for 120 minutes with hot air. Until cooled. The film thickness after curing (drying) was set to 10 μm on the etching substrate. The physical properties of the cured product are shown in Table 3. From Table 3, in the relationship between the alkoxysilane compound and the alkoxytitanium compound in this Example, the net mixing amount of alkoxytitanium is 8 to 24 wt% with respect to 100 parts by weight of the solid content of the partial hydrolyzate of the alkoxysilane compound. It can be seen that the part provides a preferred coating. When this is expressed by the elemental ratio of titanium element to silicon element, the value is 0.029 to 0.087.

比較例１

Comparative Example 1

1000 g of the partially hydrolyzed alkoxysilane compound solution of Example 1 and 470 g of silica powder (with an average particle size of 4.8 μm) and fumed silica powder subjected to surface hydrophobization treatment (average particle size of primary particles is 7 nm) 60 g of the surface treated with hexamethyldisilazane) was added, and the mixture was stirred at a liquid temperature of 20 ° C. to 30 ° C. for 30 minutes in a stirring tank having a propeller rotor. Next, this mixed solution was transferred to a ball mill and mixed for 180 minutes. The liquid temperature at the time of mixing was controlled to be 20 ° C to 30 ° C. In this way, the first liquid was prepared. On the other hand, a 50% by weight solution of butyl butyrate of tetrabutoxytitanium was prepared as the second liquid. The second liquid is added to the first liquid at a ratio of 40 parts by weight with respect to 100 parts by weight of the solid after the partial hydrolyzate solution of the alkoxysilane compound is dried at 105 ° C. for 120 minutes. The mixture was mixed at 15 ° C. for 15 minutes to obtain a liquid solder resist solution. The solder resist solution is applied on the copper foil of the FR-4 grade copper clad laminate patterned by the conventional subtractive method and the FR-4 grade substrate etched on the entire surface, and the maximum temperature is 180. The temperature was gradually raised with a temperature profile of 0 ° C., hot air drying was performed for 120 minutes in the total drying time, and then gradually cooled to room temperature in 60 minutes. The thickness of the coating after curing (drying) was 10 μm at the edge of the copper circuit.
Comparative Example 2

Instead of 470 g of the silica powder of Comparative Example 1, a hydrophobized silica powder (the powder has an average particle size of 5.0 μm and is formed by chemically reacting an organic silicon compound with hydrous silicic acid. The surface was covered with an organic group (470 g), and the same treatment as in Comparative Example 2 was performed.
Comparative Example 3

In place of 470 g of silica powder of Comparative Example 1, 360 g of kaolin powder (with an average particle diameter of 2.3 μm and a moisture content of 0.9% by weight) was blended and treated in the same manner as Comparative Example 1. did.
Comparative Example 4

  In place of 60 g of the surface-hydrophobized fumed silica powder of Example 3, 60 g of fumed silica powder that has not been surface-hydrophobized (with an average primary particle size of 12 nm) was blended, and Comparative Example 2 and Treated in the same way.

  Example 1 is a system in which potassium hexatitanate fibers are added as an additive, Example 2 is a system in which kaolin powder and alumina powder are added in addition to potassium hexatitanate fibers as additives, and Example 3 is a system in which six additives are added. This is a system in which fumed silica powder surface-hydrophobized with kaolin powder, alumina powder and hexamethyldisilazane is added in addition to potassium titanate fibers. As shown in Table 2, each of the systems has a good coating appearance, a coating hardness of 6H, sufficient hardness, heat resistance and solder heat resistance at 260 ° C. for 20 seconds, no problem, and acid resistance. There was no problem with sex.

  Example 4 is a system in which kaolin powder, alumina powder, fumed silica powder subjected to surface hydrophobization treatment and ethyl cellulose powder are added in addition to potassium hexatitanate fiber, and Example 5 is a cup in addition to potassium hexatitanate fiber. This is a system in which a ring agent-treated aluminum hydroxide powder, a surface-hydrophobized fumed silica powder, and a yellow pigment (anthraquinone yellow) and a blue pigment (copper phthalonic cyan blue) are added. As shown in Table 3, any type of coating film has no problem in surface appearance, surface hardness, solder heat resistance, acid resistance, electrical insulation, electrical voltage resistance, acid resistance, flame resistance, etc. The content of halogen, antimony and phosphorus was small.

  About the soldering resist hardened | cured material (coating) obtained by Comparative Examples 1-4, the performance test as a printed wiring board was done. The results are shown in Table 4. Moreover, the evaluation method of each performance test in the table is as described separately.

  Comparative Example 1 is a system in which a silica powder and a surface-hydrophobized fumed silica powder are added, Comparative Example 2 is a system in which a hydrophobized silica powder is added instead of the silica powder in Comparative Example 1, and Comparative Example 3 is a comparison A system in which kaolin powder was added instead of silica powder in Example 1, and Comparative Example 4 was a system in which fumed silica powder not subjected to surface hydrophobization was added instead of fumed silica powder subjected to surface hydrophobization in Example 3. is there. Any of these systems does not contain potassium titanate fibers and contains silica powder. In particular, Comparative Example 4 is a system containing fumed silica powder not subjected to surface hydrophobization treatment. From Table 4, the system that does not contain potassium titanate fiber, simply added silica particles, and the system added fumed silica powder that has not been subjected to surface hydrophobization treatment has a low hardness and a good coating is obtained. I can't understand.

The test method in each performance test in the table is as follows.
Pencil hardness: According to the test method of JISK5600, the evaluation is based on the tearing of the film. The location to be evaluated is on a copper circuit and on a substrate without a copper circuit.
Solder heat resistance: JISC5012 test method. Float in a solder bath at 260 ° C. for 20 seconds and visually observe the presence or absence of cracks in the coating and the presence or absence of separation between the coating and the substrate and the copper circuit.
Acid resistance: The test piece is immersed in a 0.5% sulfuric acid aqueous solution at 30 ° C for 10 minutes, washed with water, dried at 120 ° C for 120 minutes, allowed to cool to room temperature, and then subjected to the above-mentioned pencil hardness test and visual cracking and peeling. Observe.
Salt spray resistance: JISK5600 test method, sprayed with 5% saline solution at 35 ° C. for 96 hours, washed with water and dried, and then visually observed for cracks and peeling. In addition, the peeling of the film with cello tape (registered trademark) is observed.
Electrical insulation: Performed in accordance with JIS C5012 test method The insulation resistance between circuits after a test piece is processed at 60 ° C./90%/DC 30 V / 500 hours is measured. The circuit of the test piece was set to line / space = 125 μm / 125 μm.
Electric withstand voltage: JISC5012 test method. A line / space of the circuit = 125 μm / 125 μm is applied between the circuits at 250 V for 1 minute, and a leakage current of 0.5 mA or less is regarded as acceptable.
Flame resistance: Performed by the test method of the flame retardancy test standard UL94 of the United States. About 1.6mm thick FR-4 grade glass epoxy copper clad laminate (V94 grade certified by UL94) on both sides of the entire etched substrate, with thickness after curing (drying) A film having a thickness of 20 μm is formed, a flame resistance test is performed by a vertical method, and it is determined whether or not V-0 is passed.
Antimony, halogen and phosphorus contents: Antimony is measured by atomic absorption method, halogen is measured by ion chromatography, and phosphorus is measured by spectrophotometry.

  As described in detail above, the present invention relates to a two-component type solder resist paint and a cured product comprising the solder resist paint, and a printed wiring board provided with a film that is the cured product. More than 80% of the components by weight are inorganic. Therefore, it has high heat resistance, and can withstand high mounting temperatures due to lead-free solder used when mounting various electronic components on printed wiring boards. Also, antimony compounds, halogen compounds and phosphorus compounds Is substantially flame retardant per se, and has the characteristics that it does not adversely affect the human body and the natural environment by incineration of waste compared to conventional solder resist cured products and coatings. Furthermore, since exposure and development processes are not required, the process is simplified and the manufacturing cost is reduced. The present invention having such a feature can be effectively used in a wide industrial field using a printed wiring board.

Claims (8)

A two-component type solder resist in which a first liquid composed of a partial hydrolyzate of an alkoxysilane compound and an organic solvent and a first liquid composed of a second liquid composed of an alkoxy titanium and an organic solvent are mixed and cured. In the paint, a two-part type solder resist paint characterized in that the first liquid and / or the second liquid contains potassium titanate fibers. 2. The solder resist according to claim 1, wherein the first liquid and / or the second liquid contains at least one selected from the group consisting of kaolin powder, alumina powder, and coupling agent-treated aluminum hydroxide powder. paint. The solder resist paint according to claim 1 or 2, wherein the first liquid and / or the second liquid contains fumed silica powder subjected to surface hydrophobization treatment. The solder resist paint according to any one of claims 1 to 3, wherein the first liquid and / or the second liquid contains ethylcellulose powder. The first liquid and / or the second liquid are blended with a blue pigment containing no halogen atom and / or a yellow pigment containing no halogen atom. Solder resist paint. Solder resist hardened | cured material formed from the two-component type solder resist coating material of any one of Claims 1-5. The printed wiring board provided with the film | membrane by which pattern formation hardening was carried out from the two-component type solder resist coating material of any one of Claims 1-5. The printed wiring board according to claim 7, wherein a thickness of the coating is 7 μm to 40 μm at an edge portion of the circuit.