JP2020192579A - New rosin compound, method for producing the same, and flux and solder paste - Google Patents

Abstract

To provide a flux and a solder paste which are excellent in solderability and can enhance reliability.SOLUTION: A flux contains a new rosin compound having a high content ratio of agathin acids, and preferably further contains a thixotropic agent and a solvent. A solder paste contains a flux containing a new rosin compound, and specific solder powder. The solder powder contains a solder alloy that has an alloy composition of at least one of 25-300 mass ppm As, more than 0 mass ppm and 5,100 mass ppm or less Pb, more than 0 mass ppm and 3,000 mass ppm or less Sb, more than 0 mass ppm and 10,000 mass ppm or less Bi, and the balance Sn, and satisfies Expression (1): 275≤2As+Sb+Bi+Pb and Expression (2): 0.01≤(2As+Sb)/(Bi+Pb)≤10.00, in Expressions (1) and (2), As, Sb, Bi and Pb each represent a content in the alloy composition.SELECTED DRAWING: None

Description

The present invention relates to a novel rosin compound, a method for producing the same, a flux, and a solder paste.

Fixing and electrical connection of electronic components in electronic devices, such as mounting electronic components on printed circuit boards, is generally performed by soldering, which is the most advantageous in terms of cost and reliability. In this soldering, flux, which is an auxiliary agent that facilitates the adhesion of solder to the printed circuit board and electronic components, is used.

The flux has many useful functions such as (1) to (3) below.
(1) Metal surface cleaning action (action of chemically removing the oxide film on the metal surface of printed circuit boards and electronic components to clean the surface so that soldering is possible)
(2) Anti-oxidation action (action to cover the cleaned metal surface during soldering to block contact with oxygen and prevent the metal surface from being re-oxidized by heating)
(3) Interfacial tension lowering action (action to reduce the surface tension of molten solder and improve the wettability of metal surfaces with solder)

In particular, in order to exert the action of (1) above, it is necessary to increase the acid value (mgKOH / g) of the flux and the composition contained in the flux, and in order to increase the acid value, it is a kind of activator. The addition of an organic acid is carried out.

Further, if the flux contains a large amount of ionic substances, the metal surfaces of the printed circuit board and electronic components are easily corroded. Therefore, from the viewpoint of reducing the corrosiveness of the flux and increasing the reliability, it is desirable that the amount of ionic substances contained in the flux is small.
An aqueous solution resistivity (electric resistivity) test is used to quantify ionic substances in flux. The larger the value of the aqueous solution resistivity (Ω · m), the smaller the corrosiveness and the higher the reliability as a flux.

In addition to the above-mentioned activator such as organic acid, a base resin such as rosin is added to the flux.
As the rosin which is the base resin, natural rosin has been mainly used so far. Such natural rosin contains abietic acid as a main component, but there are some that contain agatic acids (agatic acid, dihydroagatic acid, tetrahydroagatic acid, etc.) depending on the production area of the natural rosin.

As a conventional example of a rosin containing agatinic acids, in Patent Document 1, at least 15% by weight of pimaran-type resin acid (a-1), at least 1% by weight of labdane-type resin acid (a-2), and conjugated dizygous acid. A soldered flux base resin made of rosins (A) containing at least 50% by weight of an abietane-type resin acid (a-3) having no heavy bond has been proposed.
As an example of the labdane-type resin acid (a-2), a resin acid derived from agatic acid is disclosed.

International Publication No. 2013/172295

However, it was found that the flux used in the examples of Patent Document 1 has a low acid value and insufficient solderability.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a flux and a solder paste which are excellent in solderability and can enhance reliability.

As a result of diligent research to solve the above problems, the present inventors have made a rosin component (pot) remaining in the distillation apparatus instead of the main distillate conventionally used as a purified rosin when distilling the raw material rosin. It was found that the above-mentioned problems can be solved by using the rosin component containing a large amount of agacinic acids in the remaining) as a flux, and the present invention has been completed. Specific embodiments of the present invention are as follows.

[1] A rosin compound containing rosin and agatinic acids in an amount of more than 15% by mass and 70% by mass or less.

[2] A flux containing the rosin compound according to the above [1].

[3] The flux according to the above [2], which further contains a thixotropic agent and a solvent.

[4] The flux according to the above [3], wherein the thixotropy contains at least one selected from the group consisting of an amide compound and an ester compound.

[5] The flux according to the above [4], wherein the amide compound contains at least one selected from the group consisting of polyamide, bisamide and monoamide.

[6] The above-mentioned [4] or [5], wherein the thixotropy contains at least the amide compound and contains the amide compound in an amount of more than 0% by mass and 15% by mass or less based on the total amount of the flux. flux.

[7] The flux according to any one of [4] to [6] above, wherein the ester compound contains castor oil.

[8] Any of the above [4] to [7], wherein the thixotropy contains at least the ester compound and contains the ester compound in an amount of more than 0% by mass and 8% by mass or less based on the total amount of the entire flux. The flux according to item 1.

[9] The flux according to any one of the above [2] to [8], further comprising an organic acid in an amount of 0% by mass or more and 15% by mass or less with respect to the total amount of the entire flux.

[10] Further, with respect to the total amount of the entire flux, amine is 0% by mass or more and 8% by mass or less, organic halogen compound is 0% by mass or more and 8% by mass or less, and amine hydrohalide is 0% by mass or more 3 The flux according to any one of the above [2] to [9], which contains 0% by mass or more and 8% by mass or less of an antioxidant in an amount of 0% by mass or less or an antioxidant.

[11] A solder paste containing the flux according to any one of the above [2] to [10] and a solder powder.

[12] The solder powder has As: 25 to 300 mass ppm, Pb: 0 mass ppm or more and 5100 mass ppm or less, and Sb: 0 mass ppm or more and 3000 mass ppm or less, and Bi: 0 mass ppm or more and 10000 mass ppm or less. The solder paste according to the above [11], which comprises at least one of the above and a solder alloy having an alloy composition in which the balance is Sn and satisfies the following equations (1) and (2).
275 ≦ 2As + Sb + Bi + Pb (1)
0.01 ≦ (2As + Sb) / (Bi + Pb) ≦ 10.00 (2)
In the above equations (1) and (2), As, Sb, Bi and Pb each represent the content (mass ppm) in the alloy composition.

[13] Further, the solder paste according to the above [12], wherein the alloy composition satisfies the following formula (1a).
275 ≦ 2As + Sb + Bi + Pb ≦ 25200 (1a)
In the above formula (1a), As, Sb, Bi and Pb each represent the content (mass ppm) in the alloy composition.

[14] Further, the solder paste according to the above [12], wherein the alloy composition satisfies the following formula (1b).
275 ≦ 2As + Sb + Bi + Pb ≦ 5300 (1b)
In the above formula (1b), As, Sb, Bi and Pb each represent the content (mass ppm) in the alloy composition.

[15] The solder paste according to any one of [12] to [14] above, wherein the alloy composition satisfies the following formula (2a).
0.31 ≦ (2As + Sb) / (Bi + Pb) ≦ 10.00 (2a)
In the above formula (2a), As, Sb, Bi and Pb each represent the content (mass ppm) in the alloy composition.

[16] Further, the alloy composition of the above [12] to [15] contains at least one selected from the group consisting of Ag: 0 to 4% by mass and Cu: 0 to 0.9% by mass. The solder paste according to any one item.

[17] A method for producing a rosin compound, which comprises the following steps (a) and (b).
Step (a): A step of distilling a raw material rosin compound containing agatic acids of 1% by mass or more and 15% by mass or less to concentrate the agatic acids in the raw material rosin compound Step (b): After the step (a) The step of distilling and purifying a crude rosin compound containing concentrated agatinic acids to obtain a rosin compound containing more than 15% by mass and 70% by mass or less of agatinic acids.

[18] The method for producing a rosin compound according to the above [17], wherein the raw material rosin compound selected in the step (a) is selected from the group consisting of natural rosin and hydrogenated rosin.

According to the present invention, it is possible to provide a flux and a solder paste having excellent solderability and high reliability.
Further, according to the present invention, it is possible to provide a novel rosin compound having a high content ratio of agatinic acids and a method for producing the same.

The present invention will be described in more detail below.
In the present specification, "ppm" relating to the solder alloy composition is "mass ppm" unless otherwise specified. “%” Is “mass%” unless otherwise specified.

<Rosin compound>
The rosin compound of the present embodiment contains more than 15% by mass and 70% by mass or less of agatic acids and rosin.

Examples of the agatic acids in the rosin compound include agatic acid, dihydroagatic acid, tetrahydroagatic acid and the like.

The content of agatinic acids with respect to the total mass of the rosin compound is more than 15% by mass and 70% by mass or less, preferably more than 15% by mass and 40% by mass or less, and more preferably more than 15% by mass and 30% by mass or less.
When the content of agatinic acids is within the above range, the solderability when used as a flux is excellent and the reliability is high.
The content of agatinic acids is measured using a molecular weight measurement method using a gel permeation chromatography (GPC) apparatus.

As the rosin in the rosin compound in the present embodiment, one containing either a natural rosin or a modified rosin can be used. Examples of such rosins include raw material rosins such as gum rosin, wood rosin and tall oil rosin, and derivatives obtained from the raw material rosin. Examples of the derivative include purified rosin, hydrogenated rosin, disproportionated rosin, polymerized rosin and α, β unsaturated carboxylic acid modified products (acrylicated rosin, maleated rosin, fumarized rosin, etc.), and the polymerized rosin. Examples thereof include purified products, hydrides and disproportionated products of the above, and purified products, hydrides and disproportionated products of the α, β unsaturated carboxylic acid modified products, and one or more of them can be used.

<Manufacturing method of rosin compound>
Next, a method for producing the rosin compound of the present embodiment will be described.

The method for producing a rosin compound of the present embodiment described above includes the following steps (a) and (b).
Step (a): A step of distilling a raw material rosin compound containing agatic acids of 1% by mass or more and 15% by mass or less to concentrate the agatic acids in the raw material rosin compound Step (b): After the step (a) The step of distilling and purifying a crude rosin compound containing concentrated agatinic acids to obtain a rosin compound containing more than 15% by mass and 70% by mass or less of agatinic acids.

The raw material rosin compound containing 1% by mass or more and 15% by mass or less of agatinic acids used as a raw material in the step (a) is not particularly limited as long as it contains agatinic acids, but is selected from the group consisting of natural rosin and hydrogenated rosin. It is preferable to use one. For example, as the raw material rosin compound, it is preferable to use a natural rosin such as South Apine rosin produced in China, Vietnam or Indonesia, a hydrogenated rosin of the natural rosin, or the like.

The distillation apparatus used in the step (a) is not particularly limited, but a batch distillation apparatus, a continuous distillation apparatus, a thin film distillation apparatus and the like can be used.
The pressure for distilling the raw material rosin compound in the step (a) is preferably 50 Pa or more and 400 Pa or less, more preferably 100 Pa or more and 300 Pa or less, and further preferably 100 Pa or more and 250 Pa or less.
The temperature at which the raw material rosin compound is distilled in the step (a) is preferably 100 ° C. or higher and 300 ° C. or lower, more preferably 150 ° C. or higher and 280 ° C. or lower, and further preferably 200 ° C. or higher and 270 ° C. or lower.
The distillation time for distilling the raw material rosin compound in the step (a) is preferably 0.5 hours or more and 24 hours or less, more preferably 1 hour or more and 12 hours or less, and further preferably 1.5 hours or more and 5 hours or less.

The distillation apparatus used in the purification of the step (b) is not particularly limited, but a batch distillation apparatus, a continuous distillation apparatus, a thin film distillation apparatus and the like can be used.
In the step (b), the pressure for distilling the crude rosin compound containing concentrated agatinic acids after the step (a) is preferably 50 Pa or more and 400 Pa or less, more preferably 100 Pa or more and 300 Pa or less, and 100 Pa or more and 250 Pa or less. Is even more preferable.
In the step (b), the temperature at which the crude rosin compound is distilled is preferably 100 ° C. or higher and 300 ° C. or lower, more preferably 150 ° C. or higher and 280 ° C. or lower, and further preferably 200 ° C. or higher and 270 ° C. or lower.
In the step (b), the distillation time for distilling the crude rosin compound is preferably 0.5 hours or more and 24 hours or less, more preferably 1 hour or more and 12 hours or less, and further preferably 1.5 hours or more and 5 hours or less. preferable.

In the method for producing a rosin compound of the present embodiment, it is preferable to repeat the step (a) until a desired concentration of agatinic acids is obtained, and the number of repetitions of the step (a) is preferably 1 to 100 times. It is more preferably 2 times or more and 50 times or less, and further preferably 3 times or more and 10 times or less.
Further, the step (a) in the method for producing the rosin compound may include an operation of further adding the raw material rosin compound containing 1% by mass or more and 15% by mass or less of the agatinic acids to the raw material rosin compound after concentration. ..

In the conventional method for producing rosin, the raw material rosin is distilled to remove the volatile initial distillate and the pitch component (remaining in the kettle) remaining in the distillation apparatus, and a resin of a monocarboxylic acid such as abietic acid. Purified rosin was obtained by removing the main distillate containing an acid and then purifying it.
On the other hand, in the method for producing a rosin compound of the present embodiment, a raw material rosin compound containing agatic acids is selected, and a volatile initial distillate and a main distillate containing a resin acid of a monocarboxylic acid such as abietic acid are used. A rosin compound containing a high concentration of abietic acids is obtained by distilling and removing the abietic acids contained in the components remaining in the distillation apparatus. As a result, since agatinic acids are dicarboxylic acids, they have a high acid value, and when the concentration is high, the solderability of the flux can be efficiently improved. In addition, since the agatic acids are concentrated in rosin without being isolated, they can be easily produced at low cost even on an industrial scale.

<Flux>
The flux of the present embodiment contains the above-mentioned specific rosin compound, and is particularly suitable as a flux for solder paste.
In the present embodiment, the higher the content of agatanic acids contained in the flux, the higher the solderability.
For example, the content of agatinic acids contained in the flux is preferably more than 0.5% by mass and 20% by mass or less, more preferably 1% by mass or more and 16% by mass or less, and 2% by mass with respect to the total amount of the entire flux. % Or more and 10% by mass or less are more preferable.
When the content of agatinic acids contained in the flux is within the above range, the solderability when the flux is used is excellent and the reliability is high.
The content of agatinic acids contained in the flux is preferably 2 to 40% by mass, more preferably 5 to 35% by mass, and 5 to 30% of the total amount of the solid content (excluding the solvent) of the flux. Mass% is more preferred.

For example, the flux of the present embodiment may contain a thixotropic agent and a solvent in addition to the above-mentioned specific rosin compound.

The content of the rosin compound contained in the flux is preferably 2% by mass or more and 60% by mass or less, more preferably 5% by mass or more and 50% by mass or less, and 10% by mass or more and 40% by mass with respect to the total amount of the entire flux. The following is more preferable.

Examples of the thixotropy used in the present embodiment include amide compounds, ester compounds, sorbitol-based thixotropy and the like.

Examples of the amide compound that is a thixotropic agent include monoamide, bisamide, and polyamide.
For example, such amide compounds include lauric acid amides, palmitic acid amides, stearic acid amides, behenic acid amides, hydroxystearic acid amides, saturated fatty acid amides, oleic acid amides, erucic acid amides, unsaturated fatty acid amides, p-toluamides, p. -Monoamides such as toluenemethaneamide, aromatic amide, hexamethylenehydroxystearic acid amide, substituted amide, methylolstearic acid amide, methylolamide, fatty acid esteramide; methylenebisstearic acid amide, ethylenebislauric acid amide, ethylenebishydroxy fatty acid (C6 to 24 carbon atoms of fatty acid) Amide, ethylene bishydroxystearic acid amide, saturated fatty acid bisamide, methylene bisoleic acid amide, unsaturated fatty acid bisamide, m-xylylene bisstearic acid amide, aromatic bisamide and other bisamides;
Examples thereof include polyamides such as saturated fatty acid polyamides, unsaturated fatty acid polyamides, aromatic polyamides, tris 1,2,3-propanetricarboxylic acids (2-methylcyclohexylamide), cyclic amide oligomers, and acyclic amide oligomers.

The cyclic amide oligomer includes an amide oligomer in which dicarboxylic acid and diamine are polycondensed cyclically, an amide oligomer in which tricarboxylic acid and diamine are polycondensed cyclically, an amide oligomer in which dicarboxylic acid and triamine are polycondensed cyclically, and tricarboxylic acid. Amido oligomer with cyclic polycondensation of dicarboxylic acid and triamine, amide oligomer with cyclic polycondensation of dicarboxylic acid and tricarboxylic acid and diamine, amide oligomer with cyclic polycondensation of dicarboxylic acid and tricarboxylic acid and triamine, dicarboxylic acid and diamine And an amide oligomer in which triamine is cyclically polycondensed, an amide oligomer in which tricarboxylic acid, diamine and triamine are polycondensed cyclically, and an amide oligomer in which dicarboxylic acid and tricarboxylic acid and diamine and triamine are cyclically polycondensed. ..

When the acyclic amide oligomer is an amide oligomer in which a monocarboxylic acid and diamine and / or triamine are polycondensed in an acyclic manner, the amide in which a dicarboxylic acid and / or the tricarboxylic acid and the monoamine are polycondensed acyclically. Examples thereof include the case of an oligomer. In the case of an amide oligomer containing a monocarboxylic acid or a monoamine, the monocarboxylic acid and the monoamine function as terminal molecules (terminal molecules) to form an acyclic amide oligomer having a reduced molecular weight. When the acyclic amide oligomer is an amide compound in which a dicarboxylic acid and / or a tricarboxylic acid and a diamine and / or a triamine are polycondensed in an acyclic manner, the acyclic amide oligomer is a non-cyclic polymer amide polymer. Further, the acyclic amide oligomer also includes an amide oligomer in which a monocarboxylic acid and a monoamine are acyclically condensed.

Examples of the ester compound that is a thixotropic agent include castor oil and the like.

Examples of the sorbitol-based thixo agent include dibenzylidene sorbitol, bis (4-methylbenzylidene) sorbitol, (D-) sorbitol, monobenzylidene (-D-) sorbitol, and mono (4-methylbenzylidene)-(D-) sorbitol. And so on.

One type or two or more types of thixotropic agents can be used.
The thixotropy preferably contains at least one selected from the group consisting of amide compounds and ester compounds.
The content of the thixotropy is preferably 0.1 to 15.0% by mass, more preferably 0.2% by mass or more and 10.0% by mass or less, based on the total amount of the flux.

It is preferable to use the amide compound containing at least one selected from the group consisting of polyamide, bisamide and monoamide. The flux of the present embodiment preferably contains the amide compound in an amount of more than 0% by mass and 15.0% by mass or less, and 0.2% by mass or more and 10.0% by mass or less, based on the total amount of the flux. Is more preferable.

As the ester compound, it is preferable to use a compound containing castor oil. The flux of the present embodiment preferably contains the ester compound in an amount of 0% by mass or more and 8.0% by mass or less, and more preferably 0% by mass or more and 5.0% by mass or less, based on the total amount of the flux. preferable.

Examples of the solvent used in this embodiment include water, alcohol-based solvents, glycol ether-based solvents, terpineols and the like.
As alcohol-based solvents, isopropyl alcohol, 1,2-butanediol, isobornylcyclohexanol, 2,4-diethyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, 2,5 -Dimethyl-2,5-hexanediol, 2,5-dimethyl-3-hexine-2,5-diol, 2,3-dimethyl-2,3-butanediol, 1,1,1-tris (hydroxymethyl) Ethan, 2-ethyl-2-hydroxymethyl-1,3-propanediol, 2,2'-oxybis (methylene) bis (2-ethyl-1,3-propanediol), 2,2-bis (hydroxymethyl) -1,3-propanediol, 1,2,6-trihydroxyhexane, bis [2,2,2-tris (hydroxymethyl) ethyl] ether, 1-ethynyl-1-cyclohexanol, 1,4-cyclohexanediol , 1,4-Cyclohexanedimethanol, erythritol, treitol, guayacol glycerol ether, 3,6-dimethyl-4-octin-3,6-diol, 2,4,7,9-tetramethyl-5-decine-4 , 7-diol and the like.
Glycol ether-based solvents include hexyl glycol, hexyl diglycol, 2-ethylhexyl glycol, 2-ethylhexyl diglycol, dimethyltriglycol, dibutyldiglycol, diethylene glycol mono-2-ethylhexyl ether, 2-methylpentane-2,4- Aliper glycol ether-based solvents such as diols, diethylene glycol monohexyl ethers, diethylene glycol dibutyl ethers, triethylene glycol monobutyl ethers, tetraethylene glycol monomethyl ethers, tetraethylene glycol dimethyl ethers; phenyl glycols, phenyldiglycols, benzyl glycols, benzyl diglycols, Examples thereof include aromatic glycol ether-based solvents such as ethylene glycol monophenyl ether.
As the solvent, one kind or two or more kinds can be used.

The flux of the present embodiment may contain components other than rosin, thixotropic agent and solvent. Examples of components other than rosin, thixotropy and solvent include organic acids, amines, halogen-based activators, antioxidants and the like.

Organic acids include glutaric acid, adipic acid, azelaic acid, eicosandioic acid, citric acid, glycolic acid, succinic acid, salicylic acid, diglycolic acid, dipicolinic acid, dibutylaniline diglycolic acid, suberic acid, sebacic acid, and thioglycol. Acid, terephthalic acid, dodecanedioic acid, parahydroxyphenylacetic acid, picolinic acid, phenylsuccinic acid, phthalic acid, fumaric acid, maleic acid, malonic acid, lauric acid, benzoic acid, tartaric acid, tris isocyanurate (2-carboxyethyl) , Glycin, 1,3-cyclohexanedicarboxylic acid, 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxymethyl) butanoic acid, 2,3-dihydroxybenzoic acid, 2,4-diethylglutaric acid , 2-Kinolinecarboxylic acid, 3-hydroxybenzoic acid, malic acid, p-anisic acid, stearic acid, 12-hydroxystearic acid, oleic acid, linoleic acid, linolenic acid and the like.

Examples of the organic acid include dimer acid, trimer acid, hydrogenated dimer acid which is a hydrogenated product obtained by adding hydrogen to dimer acid, and hydrogenated trimer acid which is a hydrogenated product obtained by adding hydrogen to trimer acid.

For example, dimer acid which is a reaction product of oleic acid and linoleic acid, trimer acid which is a reaction product of oleic acid and linoleic acid, dimer acid which is a reaction product of acrylic acid, trimer acid which is a reaction product of acrylic acid, and methacrylic acid. Dimeric acid, which is a reaction product of methacrylic acid, trimeric acid, which is a reaction product of methacrylic acid, dimer acid, which is a reaction product of acrylic acid and methacrylic acid, trimer acid, which is a reaction product of acrylic acid and methacrylic acid, and oleic acid. A certain dimer acid, trimer acid which is a reaction product of oleic acid, dimer acid which is a reaction product of linoleic acid, trimer acid which is a reaction product of linoleic acid, dimer acid which is a reaction product of linolenic acid, and a reaction product of linolenic acid. A certain trimer acid, dimer acid which is a reaction product of acrylic acid and oleic acid, trimer acid which is a reaction product of acrylic acid and oleic acid, dimer acid which is a reaction product of acrylic acid and linoleic acid, reaction of acrylic acid and linoleic acid Trimmer acid, which is a reaction product of acrylic acid and linolenic acid, dimer acid, which is a reaction product of acrylic acid and linolenic acid, trimeric acid, which is a reaction product of acrylic acid and linolenic acid, dimer acid, which is a reaction product of methacrylic acid and oleic acid, methacrylic acid and oleic acid. Trimmer acid, which is a reaction product of methacrylic acid and linoleic acid, dimer acid, which is a reaction product of methacrylic acid and linoleic acid, trimeric acid, which is a reaction product of methacrylic acid and linoleic acid, dimer acid, which is a reaction product of methacrylic acid and linolenic acid, and methacrylic acid. Trimmer acid, which is a reaction product of linolenic acid, dimer acid, which is a reaction product of oleic acid and linolenic acid, trimeric acid, which is a reaction product of oleic acid and linolenic acid, dimer acid, which is a reaction product of linoleic acid and linolenic acid, linole. Examples thereof include trimeric acid, which is a reaction product of acid and linolenic acid, hydrogenated dimer acid, which is a hydrogenated product of each of the above-mentioned dimer acids, and hydrogenated trimeric acid, which is a hydrogenated product of each of the above-mentioned trimeric acids.

As the organic acid, one type may be used alone, or two or more types may be mixed and used.
The flux of the present embodiment preferably contains an organic acid in an amount of 0% by mass or more and 15% by mass or less, and more preferably 0.2% by mass or more and 10% by mass or less, based on the total amount of the flux.

Examples of amines include monoethanolamine, diphenylguanidine, ditrilguanidine, ethylamine, triethylamine, cyclohexylamine, ethylenediamine, triethylenetetramine, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethyl. Imidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methyl Imidazole, 1-cyanoethyl-2-undecyl imidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecyl imidazolium trimerite, 1- Cyanoethyl-2-phenylimidazolium trimeritate, 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino-6- [2'- Undecylimidazolyl- (1')] -ethyl-s-triazine, 2,4-diamino-6- [2'-ethyl-4'-methylimidazolyl- (1')]-ethyl-s-triazine, 2, 4-Diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-Phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo [1,2-a] benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2- Methylimidazoline, 2-phenylimidazolin, 2,4-diamino-6-vinyl-s-triazine, 2,4-diamino-6-vinyl-s-triazine isocyanuric acid adduct, 2,4-diamino-6-methacryloyloxy Ethyl-s-triazine, epoxy-imidazole adduct, 2-methylbenzoimidazole, 2-octylbenzoimidazole, 2-pentylbenzoimidazole, 2- (1-ethylpentyl) benzoimidazole, 2-nonylbenzoimidazole, 2- (4) -Thiazolyl) benzoimidazole, benzoimidazole, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole , 2- (2'-Hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3', 5'-di-tert-amylphenyl) Benzotriazole, 2- (2'-hydroxy-5'-tert-octylphenyl) benzotriazole, 2,2'-methylenebis [6- (2H-benzotriazole-2-yl) -4-tert-octylphenol], 6 -(2-Benzotriazolyl) -4-tert-octyl-6'-tert-butyl-4'-methyl-2,2'-methylenebisphenol, 1,2,3-benzotriazole, 1- [N, N-bis (2-ethylhexyl) aminomethyl] benzotriazole, carboxybenzotriazole, 1- [N, N-bis (2-ethylhexyl) aminomethyl] methylbenzotriazole, 2,2'-[[(methyl-1H- Benzotriazole-1-yl) methyl] imino] bisethanol, 1- (1', 2'-dicarboxyethyl) benzotriazole, 1- (2,3-dicarboxypropyl) benzotriazole, 1-[(2-2-) Ethylhexylamino) methyl] benzotriazole, 2,6-bis [(1H-benzotriazole-1-yl) methyl] -4-methylphenol, 5-methylbenzotriazole, 5-phenyltetrazole and the like can be mentioned.

One type of amine may be used alone, or two or more types may be mixed and used.
The flux of the present embodiment may contain amine in an amount of 0% by mass or more and 8% by mass based on the total amount of the flux.

Examples of the halogen-based activator include amine hydrogen halides and organic halogen compounds.

Amine hydrohalide is a compound obtained by reacting an amine with hydrogen halide.
As the amine in the amine hydrohalide, the above-mentioned amine can be used, and examples thereof include ethylamine, cyclohexylamine, ethylenediamine, triethylamine, diphenylguanidine, ditrilguanidine, methylimidazole, 2-ethyl-4-methylimidazole and the like. Be done. Examples of hydrogen halides include hydrides of chlorine, bromine, iodine and fluorine (hydrogen chloride, hydrogen bromide, hydrogen iodide, hydrogen fluoride). Further, borofluoric acid may be contained in place of the amine hydrohalide or in combination with the amine halide hydride, and examples of the borofluoric acid include borohydrofluoric acid.
Examples of the amine hydrogen halide include aniline hydrogen chloride, cyclohexylamine hydrogen chloride, aniline hydrogen bromide, diphenylguanidine hydrogen bromide, ditrilguanidine hydrogen bromide, ethylamine hydrogen bromide and the like.

Examples of the organic halogen compound include trans-2,3-dibromo-2-butane-1,4-diol, triallyl isocyanurate hexabromide, 1-bromo-2-butanol, 1-bromo-2-propanol and 3-bromo. -1-propanol, 3-bromo-1,2-propanediol, 1,4-dibromo-2-butanol, 1,3-dibromo-2-propanol, 2,3-dibromo-1-propanol, 2,3- Dibromo-1,4-butanediol, 2,3-dibromo-1,4-butanediol, 2,3-dibromo-2-butene-1,4-diol, tris isocyanurate (2,3-dibromopropyl), Examples thereof include chlorendic anhydride.

The flux of the present embodiment may contain an organic halogen compound in an amount of 0% by mass or more and 8% by mass or less and an amine hydrohalide hydrochloride in an amount of 0% by mass or more and 3% by mass or less based on the total amount of the flux.

Examples of the antioxidant include a hindered phenolic antioxidant and the like.
The flux of the present embodiment preferably contains an antioxidant in an amount of 0% by mass or more and 8% by mass or less based on the total amount of the flux.

The flux of the present embodiment may further contain a resin component other than rosin.
Examples of the resin component other than rosin include acrylic resin, terpene resin, modified terpene resin, terpenephenol resin, modified terpenephenol resin, styrene resin, modified styrene resin, xylene resin, modified xylene resin and the like.
As the modified terpene resin, an aromatic modified terpene resin, a hydrogenated terpene resin, a hydrogenated aromatic modified terpene resin and the like can be used. As the modified terpene phenol resin, hydrogenated terpene phenol resin or the like can be used. As the modified styrene resin, styrene acrylic resin, styrene maleic anhydride and the like can be used. Examples of the modified xylene resin include a phenol-modified xylene resin, an alkylphenol-modified xylene resin, a phenol-modified resol-type xylene resin, a polyol-modified xylene resin, and a polyoxyethylene-added xylene resin.

The flux of the present embodiment may further contain a surfactant.
Examples of the surfactant here include polyoxyalkylene acetylene glycols, polyoxyalkylene glyceryl ether, polyoxyalkylene alkyl ether, polyoxyalkylene ester, polyoxyalkylene alkyl amine, and polyoxyalkylene alkyl amide.

The flux of the present embodiment described above is particularly suitable for solder paste. By applying such a flux to the solder paste, the solderability is excellent and the reliability can be enhanced.

Further, the flux of the present embodiment is not limited to that for solder paste, and can also be applied as a liquid flux for flow soldering. The main component of this liquid flux is a solvent, and it contains a volatile solvent such as isopropyl alcohol, and spray coating or the like is generally used. For example, examples of the liquid flux to which the flux of the present embodiment is applied include a flux in which a part or all of the rosin-based resin in the flux described in Japanese Patent No. 63222881 is replaced with the rosin compound according to the present invention. By applying the flux of the present embodiment to the liquid flux, the solderability is excellent and the reliability can be enhanced.

The reason why the above-mentioned effects of the present invention can be obtained is not clear, but it is presumed as follows.
Rosin is a highly crystalline component. If rosin, which is the main component of the flux residue, causes cracks in the residue, there are inconveniences such as easy absorption of moisture from the cracks. All agatic acids have a flexible structure even when compared with the structure of rosin, particularly abietic acid, which is the main component. Therefore, as the content of agatinic acids increases, the crystallization of rosin is inhibited and the residue tends to be soft. Therefore, it is considered that the effect of the present invention can be obtained by the flux containing the rosin compound of the present embodiment.

<Solder paste>
The solder paste of the present embodiment contains the above-mentioned flux and solder powder.

The solder powder is a solder powder of Sn alone, Sn-Ag type, Sn-Cu type, Sn-Ag-Cu type, Sn-Bi type, Sn-In type, etc., or Sb, an alloy thereof. Any one composed of a powder of a solder alloy to which Bi, Pb, In, Cu, Zn, As, Ag, Cd, Fe, Ni, Co, Au, Ge, P and the like are added can be used arbitrarily.

In one embodiment, the solder powder has As: 25 to 300 mass ppm, Pb: 0 mass ppm and 5100 mass ppm or less, and Sb: 0 mass ppm and 3000 mass ppm or less, and Bi: 0 mass ppm and 10000 mass ppm. Those containing at least one of the following and a solder alloy having an alloy composition in which the balance is Sn and satisfying the following equations (1) and (2) (hereinafter referred to as "solder powder (Sp)") are preferable.
275 ≦ 2As + Sb + Bi + Pb (1)
0.01 ≦ (2As + Sb) / (Bi + Pb) ≦ 10.00 (2)
In the above equations (1) and (2), As, Sb, Bi and Pb each represent the content (mass ppm) in the alloy composition.

1. 1. Alloy composition
(1) As: 25 to 300 mass ppm
As is an element capable of suppressing a change in the viscosity of the solder paste over time. It is presumed that As has low reactivity with flux and is a noble element with respect to Sn, so that it can exert an effect of suppressing thickening. If As is less than 25 mass ppm, the thickening suppressing effect cannot be sufficiently exhibited. The lower limit of the As content is 25 mass ppm or more, preferably 50 mass ppm or more, and more preferably 100 mass ppm or more. On the other hand, if the amount of As is too large, the wettability of the solder alloy deteriorates. The upper limit of the As content is 300 mass ppm or less, preferably 250 mass ppm or less, and more preferably 200 mass ppm or less.

(2) At least one kind of Sb having Pb: more than 0 mass ppm and 5100 mass ppm or less, Sb: more than 0 mass ppm and 3000 mass ppm or less, and Bi: more than 0 mass ppm and 10000 mass ppm or less has low reactivity with flux. It is an element that has an effect of suppressing thickening. When the solder alloy in the present embodiment contains Sb, the lower limit of the Sb content is 0 mass ppm or more, preferably 25 mass ppm or more, more preferably 50 mass ppm or more, and further preferably 100 mass ppm. It is ppm or more, and particularly preferably 300 mass ppm or more. On the other hand, if the Sb content is too large, the wettability deteriorates, so it is necessary to set the content to an appropriate level. The upper limit of the Sb content is 3000 mass ppm or less, preferably 1150 mass ppm or less, and more preferably 500 mass ppm or less.

Like Sb, Bi and Pb are elements that have low reactivity with flux and exhibit an effect of suppressing thickening. Further, Bi and Pb are elements that can suppress deterioration of wettability due to As because the liquidus temperature of the solder alloy is lowered and the viscosity of the molten solder is reduced.

If at least one element of Pb, Sb, and Bi is present, deterioration of wettability due to As can be suppressed. When the solder alloy in the present embodiment contains Bi, the lower limit of the Bi content is 0 mass ppm or more, preferably 25 mass ppm or more, more preferably 50 mass ppm or more, and further preferably 75 mass ppm. It is ppm or more, particularly preferably 100 mass ppm or more, and most preferably 250 mass ppm or more. The lower limit of the Pb content is 0 mass ppm or more, preferably 25 mass ppm or more, more preferably 50 mass ppm or more, further preferably 75 mass ppm or more, and particularly preferably 100 mass ppm or more. Yes, most preferably 250 mass ppm or more.

On the other hand, if the content of these elements is too large, the solidus temperature is remarkably lowered, so that ΔT, which is the temperature difference between the liquidus temperature and the solidus temperature, becomes too wide. If ΔT is too wide, the liquid phase Bi and Pb will be concentrated because a high melting point crystal phase having a low content of Bi and Pb is precipitated in the solidification process of the molten solder. After that, when the temperature of the molten solder is further lowered, the low melting point crystal phase having a high concentration of Bi and Pb is segregated. Therefore, the mechanical strength and the like of the solder alloy are deteriorated, and the reliability is deteriorated. In particular, since the crystal phase having a high Bi concentration is hard and brittle, segregation in the solder alloy significantly lowers the reliability.

From this point of view, when the solder alloy in the present embodiment contains Bi, the upper limit of the Bi content is 10,000 mass ppm or less, preferably 1000 mass ppm or less, and more preferably 600 mass ppm or less. More preferably, it is 500 mass ppm or less. The upper limit of the Pb content is 5100 mass ppm or less, preferably 5000 mass ppm or less, more preferably 1000 mass ppm or less, further preferably 850 mass ppm or less, and particularly preferably 500 mass ppm or less. is there.

(3) Equation (1) The solder alloy in this embodiment must satisfy the following equation (1).

275 ≦ 2As + Sb + Bi + Pb (1)
In the above formula (1), As, Sb, Bi and Pb each represent the content (mass ppm) in the alloy composition.

As, Sb, Bi and Pb are all elements exhibiting a thickening suppressing effect, and the total of these elements needs to be 275 mass ppm or more. In the formula (1), the As content is doubled because As has a higher effect of suppressing thickening than Sb, Bi and Pb.

If the formula (1) is less than 275, the thickening suppressing effect is not sufficiently exhibited. The lower limit of the equation (1) is 275 or more, preferably 350 or more, and more preferably 1200 or more. On the other hand, the upper limit of the formula (1) is not particularly limited from the viewpoint of the thickening suppressing effect, but is preferably 25200 or less, more preferably 10200 or less, from the viewpoint of setting ΔT in a suitable range. It is more preferably 5300 or less, and particularly preferably 3800 or less.

The following equations (1a) and (1b) are obtained by appropriately selecting the upper limit and the lower limit from the above preferred embodiments.

275 ≦ 2As + Sb + Bi + Pb ≦ 25200 (1a)
275 ≦ 2As + Sb + Bi + Pb ≦ 5300 (1b)
In the above formulas (1a) and (1b), As, Sb, Bi and Pb each represent the content (mass ppm) in the alloy composition.

(4) Equation (2) The solder alloy in this embodiment must satisfy the following equation (2).

0.01 ≦ (2As + Sb) / (Bi + Pb) ≦ 10.00 (2)
In the above formula (2), As, Sb, Bi and Pb each represent the content (mass ppm) in the alloy composition.

If the contents of As and Sb are large, the wettability of the solder alloy deteriorates. On the other hand, Bi and Pb suppress the deterioration of wettability due to the inclusion of As, but if the content is too large, ΔT increases, so strict control is required. In particular, in an alloy composition containing Bi and Pb at the same time, ΔT tends to increase. In view of these, if the contents of Bi and Pb are increased to excessively improve the wettability, ΔT will spread. On the other hand, if the content of As and Sb is increased to improve the thickening suppressing effect, the wettability is deteriorated. Therefore, in the present embodiment, the group is divided into As and Sb groups, Bi and Pb groups, and when the total amount of both groups is within an appropriate predetermined range, the thickening suppressing effect, ΔT narrowing, and wetting All of the sex is satisfied at the same time.

If the equation (2) is less than 0.01, the total content of Bi and Pb is relatively large as compared with the total content of As and Sb, so that ΔT spreads. The lower limit of the formula (2) is 0.01 or more, preferably 0.02 or more, more preferably 0.41 or more, further preferably 0.90 or more, and particularly preferably 1.00 or more. Most preferably, it is 1.40 or more. On the other hand, when the equation (2) exceeds 10.00, the total content of As and Sb becomes relatively larger than the total content of Bi and Pb, so that the wettability deteriorates. The upper limit of the formula (2) is 10.00 or less, preferably 5.33 or less, more preferably 4.50 or less, still more preferably 2.67 or less, and even more preferably 2.50. It is less than or equal to, and particularly preferably 2.30 or less.

The denominator of Eq. (2) is "Bi + Pb", and Eq. (2) cannot be established unless these are included. That is, the solder alloy in this embodiment always contains at least one of Bi and Pb. The alloy composition containing no Bi and Pb is inferior in wettability as described above.
The following equation (2a) is obtained by appropriately selecting the upper limit and the lower limit from the above preferred embodiments.

0.31 ≦ (2As + Sb) / (Bi + Pb) ≦ 10.00 (2a)
In the above formula (2a), As, Sb, Bi and Pb each represent the content (mass ppm) in the alloy composition.

(5) At least one Ag selected from the group consisting of Ag: 0 to 4% by mass and Cu: 0 to 0.9% by mass forms Ag ₃ Sn at the crystal interface to improve the reliability of the solder alloy. It is an arbitrary element that can be used. In addition, Ag is an element whose ionization tendency is noble with respect to Sn, and when it coexists with As, Pb and Bi, it promotes the effect of suppressing thickening of these elements. The Ag content is preferably 0 to 4% by mass, more preferably 0.5 to 3.5% by mass, and further preferably 1.0 to 3.0% by mass.

Cu is an optional element that can improve the joint strength of solder joints. Further, Cu is an element whose ionization tendency is noble with respect to Sn, and when it coexists with As, Pb and Bi, it promotes the effect of suppressing thickening of these elements. The Cu content is preferably 0 to 0.9% by mass, more preferably 0.1 to 0.8% by mass, and even more preferably 0.2 to 0.7% by mass.

(6) Remaining: Sn
The rest of the solder alloy in this embodiment is Sn. In addition to the above-mentioned elements, unavoidable impurities may be contained. Even if it contains unavoidable impurities, it does not affect the above-mentioned effects. Further, as will be described later, even if an element not contained in the present invention is contained as an unavoidable impurity, it does not affect the above-mentioned effect. If the content of In is too large, ΔT spreads, so if it is 1000 mass ppm or less, the above-mentioned effect is not affected.

2. 2. Solder powder The solder powder in the present embodiment preferably satisfies the size (particle size distribution) satisfying symbols 1 to 8 in the powder size classification (Table 2) in JIS Z 3284-1: 2014. A size satisfying symbols 4 to 8 (particle size distribution) is more preferable, and a size satisfying symbols 5 to 8 (particle size distribution) is more preferable. When the particle size satisfies this condition, the surface area of the powder is not too large and the increase in viscosity is suppressed, and the aggregation of the fine powder is suppressed and the increase in viscosity may be suppressed. Therefore, it is possible to solder to finer parts.

Flux content:
The flux content is preferably 5 to 95% by mass, more preferably 5 to 15% by mass, based on the total mass of the solder paste.
When the content of the flux in the solder paste is in this range, the thickening suppressing effect caused by the solder powder is sufficiently exhibited. In addition, corrosion of the metal surface of the printed circuit board and electronic components is further suppressed, and reliability is enhanced.

The solder paste of the present embodiment preferably further contains zirconium oxide powder. By containing zirconium oxide, it is possible to suppress an increase in the viscosity of the paste due to aging. It is presumed that this is because the zirconium oxide is contained so that the oxide film thickness on the surface of the solder powder is maintained in the state before being put into the flux. Details are unknown, but it is inferred as follows. Normally, the active component of the flux has a slight activity even at room temperature, so that the surface oxide film of the solder powder becomes thin due to reduction, which causes the powders to aggregate with each other. Therefore, it is presumed that by adding the zirconium oxide powder to the solder paste, the active component of the flux reacts preferentially with the zirconium oxide powder, and the oxide film on the surface of the solder powder is maintained to such an extent that it does not aggregate.

In order to fully exert such effects, the content of the zirconium oxide powder in the solder paste is preferably 0.05 to 20.0% by mass with respect to the total mass of the solder paste. When it is 0.05% by mass or more, the above-mentioned action and effect can be exhibited, and when it is 20.0% by mass or less, the content of the metal powder can be secured and the thickening prevention effect can be exhibited. Can be done. The content of the zirconium oxide powder is more preferably 0.05 to 10.0% by mass, and the further preferable content is 0.1 to 3% by mass.

The particle size of the zirconium oxide powder in the solder paste is preferably 5 μm or less. When the particle size is 5 μm or less, the printability of the paste can be maintained. The lower limit of the particle size is not particularly limited, but may be 0.5 μm or more.
For the particle size of the zirconium oxide powder, an SEM photograph of the zirconium oxide powder is taken, and the diameter corresponding to the projected circle is obtained by image analysis for each powder of 0.1 μm or more, and the average value thereof is used.

The shape of zirconium oxide is not particularly limited, but if it has a different shape, the contact area with the flux is large and there is an effect of suppressing thickening. When it is spherical, good fluidity can be obtained, so that excellent printability as a paste can be obtained. The shape may be appropriately selected according to the desired characteristics.

How to make solder paste:
The solder paste of this embodiment is produced by a method common in the art.
First, for the production of the solder powder, known methods such as a dropping method in which molten solder material is dropped to obtain particles, a spraying method in which centrifugal spray is applied, and a method in which bulk solder material is crushed can be adopted. In the dropping method and the spraying method, the dropping and spraying are preferably performed in an inert atmosphere or a solvent in order to form particles. Then, each of the above components can be heated and mixed to prepare a flux, and the solder powder can be introduced into the flux, stirred and mixed for production.

<Example of action and effect of flux and solder paste of this embodiment>
In the present embodiment, since a flux containing a rosin compound containing agatanic acids in a specific ratio, preferably a soldering agent and a solvent is used, corrosion of the metal surface of the printed circuit board and electronic parts is further suppressed. Excellent solderability and high reliability.
In addition, such a flux is combined with a solder powder containing Sn and a solder alloy having an alloy composition in which a specific element (at least one of As, Pb and Sb and Bi) is used in a specific ratio as a solder powder. The solder paste is less likely to change with time such as an increase in viscosity, has excellent wettability, and exhibits high mechanical properties. Further, according to this solder paste, the corrosiveness can be lowered and the reliability can be improved.

The joining method using the solder paste according to the present invention may be carried out according to a conventional method using, for example, a reflow method. When flow soldering is performed, the melting temperature of the solder alloy may be approximately 20 ° C. higher than the liquidus temperature. Further, when joining using the solder alloy in the present embodiment, it is preferable to consider the cooling rate at the time of solidification from the viewpoint of microstructure miniaturization. For example, the solder joint is cooled at a cooling rate of 2 to 3 ° C./s or higher. Other joining conditions can be appropriately adjusted according to the alloy composition of the solder alloy.

As the solder alloy in the present embodiment, a low α-dose alloy can be produced by using a low α-dose material as a raw material thereof. When such a low α-dose alloy is used for forming solder bumps around a memory, soft errors can be suppressed.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these examples.

[Manufacturing of rosin compounds]
Production of rosin compound (I):
200 kg of hydrogenated rosin produced in Vietnam was charged into a vacuum distillation apparatus, and distilled at 250 ° C. for 3 hours under a reduced pressure of 200 Pa under a nitrogen seal. Then, each fraction such as the initial fraction and the main fraction was removed to obtain a rosin compound (IA) remaining in the vacuum distillation apparatus.
Next, 100 kg of hydrogenated rosin produced in Vietnam was further added (recharged) to the rosin compound (IA) in the vacuum distillation apparatus, and distillation was performed for 3 hours under the same distillation conditions as above, and the rosin compound remaining in the vacuum distillation apparatus (re-injection). IB) was obtained. Then, a fraction having a liquid phase temperature of 235 ° C. or higher and 260 ° C. or lower was taken out to obtain a final purified product, rosin (I).

Production of rosin compound (II):
Distillation similar to the above "Production of rosin compound (I)" was repeated three times (that is, re-injection of hydrogenated rosin, distillation, re-injection of hydrogenated rosin, and distillation were repeated to remove the agatic acid remaining in the kettle. (Concentration), the final purified product, rosin compound (II), was obtained.

Production of rosin compound (III):
Distillation similar to the above "Production of rosin compound (I)" was repeated 5 times to obtain rosin compound (III) as a final purified product.

Production of rosin compound (IV):
Distillation similar to the above "Production of rosin compound (I)" was repeated 7 times to obtain rosin compound (IV) as a final purified product.

Production of rosin compound (V):
The rosin compound (IA) in the above-mentioned "Production of rosin compound (I)" was used as the rosin compound (V).

Then, with respect to the obtained rosin compounds (I) to (V), the components contained in each rosin compound were analyzed by measuring the molecular weight using a gel permeation chromatography (GPC) apparatus. The evaluation results are shown in Table 1 below.
The numerical value of each component in Table 1 represents the mass% of each component with respect to the total mass of the rosin compound.

[Preparation of flux]
A flux (composition shown in Example 1) is obtained by mixing 25 parts by mass of rosin compound (I) as a rosin compound, 6 parts by mass of polyamide as an amide compound as a thixo agent, and 69 parts by mass of tetraethylene glycol monomethyl ether as a solvent. Flux consisting of) was prepared.

Further, as shown in Tables 2 to 10, fluxes having the respective compositions shown in Examples 2 to 50 and Comparative Examples 1 to 3 were prepared by mixing each component in the same manner as in Example 1 described above. ..

The composition in Tables 2 to 10 is mass% when the total amount of flux is 100% by mass.
In the table, an aliphatic polyamide was used as the polyamide. Hexamethylenebishydroxystearic acid amide was used as the bisamide. P-toluamide was used as the monoamide.

Next, the acid value (mgKOH / g) of the flux was measured and the solderability was evaluated when the fluxes of each example shown in Tables 2 to 10 were used. In addition, the aqueous solution specific resistance (electric resistivity) (Ω · m) of the flux was measured to evaluate the reliability. The details are as follows.

<Evaluation of solderability>
(1) Verification method The acid value (mgKOH / g) of the flux of each example shown in Tables 2 to 10 was measured based on JIS Z 3197: 2012. Then, the solderability was evaluated according to the following criteria.

(2) Judgment criteria ◯: The acid value of the flux is 50 mgKOH / g or more, and it has sufficient activity.
X: The acid value of the flux is less than 50 mgKOH / g, and the activity is insufficient.
In the solder paste, the higher the acid value of the flux, the stronger the action of cleaning the metal surface, which means that the solderability is good.

<Evaluation of reliability>
(1) Verification method For the flux of each example shown in Tables 2 to 10, the aqueous solution resistivity (electric resistivity) (Ω · m) was measured based on JIS Z 3197: 2012. Then, the reliability was evaluated according to the following criteria.

(2) Judgment criteria XX: The aqueous solution resistivity of the flux is 1000 Ω · m or more.
◯: The aqueous solution resistivity of the flux is 500 Ω · m or more and less than 1000 Ω · m.
X: The aqueous solution resistivity of the flux is less than 500 Ω · m.
In the solder paste, the higher the aqueous solution resistivity of the flux, the stronger the corrosion suppressing effect on the metal surface, which means that the reliability is high.

<Comprehensive evaluation (1)>
〇: In Tables 2 to 10, each evaluation of solderability and reliability is 〇.
X: In Tables 2 to 10, at least one of the evaluations of solderability and reliability is x.

The evaluation results are shown in Tables 2-10.

When the flux having the composition shown in Example 1 was used, sufficient effects were obtained for the effect of cleaning the metal surface and suppressing the corrosion of the metal surface.
From these results, the flux having the composition shown in Example 1 and the solder powder having each alloy composition shown in Test Examples 1 to 108 described later were mixed (solder powder: flux = 89: 11 (mass ratio). )) It can be said that a solder paste that does not easily change with time such as an increase in viscosity, has excellent wettability, has high mechanical properties, has excellent solderability, and has improved reliability can be prepared. ..

As shown in Examples 2 to 4, the metal surface can also be combined with a plurality of types of amide compounds containing the rosin compound (I) within the range specified in the present invention and changing the type of the amide compound which is a thixo agent. Sufficient effect was obtained on the cleaning of the metal surface and the effect of suppressing corrosion on the metal surface.

As shown in Example 5, the metal surface can be cleaned and the metal surface can be corroded by including the ester compound, which contains the rosin compound (I) within the range specified in the present invention and combines a plurality of types of amide compounds. A sufficient effect was obtained for the inhibitory effect.

As shown in Example 6, the metal surface can be cleaned by combining the rosin compound (I) within the range specified in the present invention, combining a plurality of types of amide compounds, including an ester compound, and changing the type of solvent. A sufficient effect was obtained on the effect of suppressing corrosion of the metal surface.

As shown in Examples 7 to 8, increasing or decreasing the amount of the rosin compound (I) within the range specified in the present invention also has a sufficient effect on the effect of cleaning the metal surface and suppressing the corrosion of the metal surface. was gotten.

As shown in Examples 9 to 12, even by combining a plurality of types of rosin compounds by changing the type of the rosin compound, sufficient effects were obtained for the effect of cleaning the metal surface and suppressing the corrosion of the metal surface.

As shown in Examples 13 to 15, the metal surface can also be cleaned by increasing the amount of the amide compound, which is a thixo agent, containing the rosin compound (I) within the range specified in the present invention and containing the organic acid. , A sufficient effect was obtained on the corrosion suppressing effect of the metal surface.

As shown in Examples 16 to 20, the rosin compound (I) within the range specified in the present invention is contained, and the type of organic acid is changed, a plurality of types of organic acids are combined, or the amount of organic acid is changed. , Sufficient effect was obtained for cleaning the metal surface and suppressing corrosion of the metal surface.

As shown in Examples 21 and 22, the effect of purifying the metal surface and suppressing the corrosion of the metal surface also by containing the rosin compound (I) within the range specified in the present invention, the organic acid, and the amine. Sufficient effect was obtained.

As shown in Examples 23 and 24, even if a halogen-based activator containing a rosin compound (I) within the range specified in the present invention and containing an organic acid is contained, the metal surface can be cleaned and the metal surface can be cleaned. A sufficient effect was obtained for the corrosion suppression effect.

As shown in Example 25, even if the rosin compound (I) within the range specified in the present invention is contained and an antioxidant containing an organic acid is contained, the effect of cleaning the metal surface and suppressing the corrosion of the metal surface is also achieved. Sufficient effect was obtained.

As shown in Example 26, it contains a rosin compound (I) within the range specified in the present invention, and even if the amount of the organic acid is reduced, it contains an antioxidant containing an amine, including a halogen-based activator. As a result, a sufficient effect was obtained on the effect of cleaning the metal surface and suppressing the corrosion of the metal surface.

As shown in Examples 27 and 28, even if the amount of the rosin compound (I) containing an organic acid and within the range specified in the present invention is changed, the effect of cleaning the metal surface and suppressing the corrosion of the metal surface can be obtained. A sufficient effect was obtained.

As shown in Examples 29 to 33, an organic acid containing a rosin compound (I) within the range specified in the present invention, containing an ester compound, changing the type of organic acid, combining a plurality of types of organic acids, Even by changing the amount, a sufficient effect was obtained on the cleaning of the metal surface and the effect of suppressing corrosion on the metal surface.

As shown in Examples 34 and 35, the metal surface can be cleaned by containing the rosin compound (I) within the range specified in the present invention, the ester compound, the organic acid, and the amine. A sufficient effect was obtained on the surface corrosion suppressing effect.

As shown in Examples 36 and 37, the metal surface can also be cleaned by containing the rosin compound (I) within the range specified in the present invention, containing the ester compound, containing the organic acid, and containing the halogen-based activator. A sufficient effect was obtained on the effect of suppressing corrosion of the metal surface.

As shown in Example 38, the metal surface can be cleaned by containing the rosin compound (I) within the range specified in the present invention, the ester compound, the organic acid, and the antioxidant. A sufficient effect was obtained on the surface corrosion suppressing effect.

As shown in Example 39, the rosin compound (I) within the range specified in the present invention is contained, the ester compound is contained, and even if the amount of the organic acid is reduced, the amine is contained and the halogen-based activator is contained. Further, by containing an antioxidant, a sufficient effect was obtained for cleaning the metal surface and suppressing corrosion of the metal surface.

As shown in Examples 40 and 41, even if the amount of the rosin compound (I) containing the organic acid, the ester compound, and the range specified in the present invention is changed, the metal surface can be cleaned and the metal surface can be cleaned. A sufficient effect was obtained for the corrosion suppression effect.

As shown in Example 42, the metal surface is cleaned even if the rosin compound (I) within the range specified in the present invention is contained, the organic acid is contained, the ester compound is contained, and the amount of the amide compound is increased. A sufficient effect was obtained on the corrosion suppressing effect of the metal surface.

As shown in Examples 43 to 46, the amount of the ester compound even if the rosin compound (I) within the range specified in the present invention is contained, the organic acid is contained, the ester compound is contained, and the amount of the amide compound is reduced. By increasing the amount of the mixture, sufficient effects were obtained for the tixo property of the flux, the cleaning of the metal surface, and the effect of suppressing corrosion of the metal surface.

As shown in Example 47, even if the amount of the rosin compound (I) within the range specified in the present invention, the organic acid, and the amide compound which is a thixo agent is increased, the metal surface can be cleaned and the metal can be cleaned. A sufficient effect was obtained on the surface corrosion suppressing effect.

As shown in Examples 48 and 49, even if the content of the amide compound which contains an organic acid and is a thixo agent is reduced, the metal surface is contained by containing the rosin compound (I) within the range specified in the present invention. Sufficient effect was obtained on the cleaning of the metal surface and the effect of suppressing corrosion on the metal surface.

As shown in Example 50, by containing an organic acid, an ester compound, and a rosin compound (I) within the range specified in the present invention, the metal surface can be cleaned and the metal surface can be suppressed from corrosion. On the other hand, a sufficient effect was obtained.

On the other hand, as shown in Comparative Example 1, by containing the rosin compound (V) whose content of agatinic acids is outside the range specified in the present invention, the metal surface is cleaned and the metal surface is suppressed from corrosion. A sufficient effect was not obtained for the effect.

Further, as shown in Comparative Example 2, if the rosin compound was not contained within the range specified in the present invention, a sufficient effect on the effect of cleaning the metal surface and suppressing the corrosion of the metal surface could not be obtained.

Further, as compared with Comparative Example 3, in the flux to which the present invention is applied, a smaller amount of organic acid has a sufficient effect on both the cleaning of the metal surface and the corrosion suppressing effect of the metal surface. It was confirmed that it could be obtained.

As described above, when the flux having the composition shown in Examples 1 to 50 was used, sufficient effects were obtained for both the cleaning of the metal surface and the corrosion suppressing effect of the metal surface.

[Manufacturing of solder paste]
Solder powders having the alloy compositions shown in Tables 11 to 16 and having a size (particle size distribution) satisfying symbol 4 in the powder size classification (Table 2) in JIS Z 3284-1: 2014 (Test Examples 1 to 108, Test Example 201). ~ 278) was prepared.
However, Test Examples 1, 5-11, 13-15, 18, 19, 23-29, 31-33, 36, 37, 41-47, 49-51, 54, 55, 59-65, 67-69, The solder powders of 72, 73, 77 to 83, 85 to 87, 90, 91, 95 to 101, 103 to 105, and 108 correspond to the above-mentioned "solder powder (Sp)".

The above-mentioned flux having the composition shown in Example 21 and the solder powder having the alloy composition of each example shown in Tables 11 to 16 were mixed to prepare a solder paste. The mass ratio of the flux to the solder powder was set to flux: solder powder = 11:89.

When the solder powder of each example was used, the change in viscosity of the solder paste with time was measured. In addition, the liquidus temperature and the solidus temperature of the solder powder were measured. Furthermore, the wettability was evaluated using the solder paste immediately after production. The details are as follows.

<Evaluation of changes in viscosity of solder paste over time>
(1) Verification method For each solder paste immediately after production, the viscosity was measured for 12 hours in the air at a rotation speed of 10 rpm and 25 ° C. using PCU-205 manufactured by Malcolm Co., Ltd.

(2) Judgment Criteria A: The viscosity after 12 hours is 1.2 times or less as compared with the viscosity when 30 minutes have passed after the solder paste was prepared.
B: The viscosity after 12 hours exceeds 1.2 times the viscosity when 30 minutes have passed after the solder paste was prepared.

<Evaluation of ΔT>
(1) Verification method For the solder powder before mixing with the flux, DSC measurement was performed using SII Nanotechnology Co., Ltd., model number: EXSTAR DSC7020, sample volume: about 30 mg, and heating rate: 15 ° C./min. The solid-phase line temperature and the liquid-phase line temperature were obtained. ΔT was obtained by subtracting the solidus temperature from the obtained liquidus temperature.

(2) Judgment criteria A: ΔT is 10 ° C. or lower.
B: ΔT exceeds 10 ° C.

<Evaluation of wettability>
Each solder paste immediately after production was printed on the Cu plate, a N ₂ atmosphere in a reflow furnace, after heating from 25 ° C. to 260 ° C. at a heating rate of 1 ° C. / s, and cooled to room temperature. Wetability was evaluated by observing the appearance of the solder bumps after cooling with an optical microscope.

A: When unmelted solder powder is not observed.
B: When unmelted solder powder is observed.

<Comprehensive evaluation (2)>
A: In Tables 11 to 16, each evaluation of aging, ΔT, and wettability is 〇.
B: In Tables 11 to 16, at least one of the evaluations of change with time, ΔT, and wettability is ×.

The evaluation results are shown in Tables 11-16.

As shown in Tables 11 to 16, it was confirmed that when the solder powders of Test Examples 1 to 108 were used, the thickening suppressing effect, the narrowing of ΔT, and the excellent wettability were exhibited in any of the alloy compositions. It was.

On the other hand, when the solder powders of Test Examples 201, 214, 227, 240, 253 and 266 were used, the result showed that the thickening suppressing effect was not exhibited because As was not contained.

When the solder powders of Test Examples 202, 215, 228, 241, 254 and 267 were used, the effect of suppressing thickening was not exhibited because the formula (1) was less than the lower limit.

When the solder powders of Test Examples 203, 216, 229, 242, 255 and 268 were used, the wettability was inferior because the equation (2) exceeded the upper limit.

When the solder powders of Test Examples 204, 205, 217, 218, 230, 231, 243, 244, 256, 257, 269 and 270 were used, the As content and the formula (2) exceeded the upper limit, so that they were wet. The result was inferior in sex.

When the solder powders of Test Examples 206 to 208, 219 to 221 and 232 to 234, 245 to 247, 258 to 260 and 271 to 273 were used, the Sb content exceeded the upper limit, resulting in poor wettability. Indicated.

When the solder powders of Test Examples 209, 210, 222, 223, 235, 236, 248, 249, 261, 262, 274 and 275 were used, ΔT exceeded 10 ° C. because the Bi content exceeded the upper limit. The results are shown.

When the solder powders of Test Examples 211, 213, 224, 226, 237, 239, 250, 252, 263, 265, 276 and 278 are used, ΔT exceeds 10 ° C. because the Pb content exceeds the upper limit. The results are shown.

When the solder powders of Test Examples 212, 225, 238, 251, 264 and 277 were used, Bi and Pb were not contained and the equation (2) was not established, so that the wettability was inferior.

Further, the flux having each composition shown in Examples 1 to 20 and 22 to 50 and the solder powder having each alloy composition shown in Test Examples 1 to 108 are mixed (solder powder: flux = 89: 11 (mass)). The solder paste produced in (ratio)) also exhibits a thickening suppressing effect, a narrowing of ΔT, and excellent wettability, as in the case of a solder paste using a flux having the composition shown in Example 21. Was confirmed.

From these results, by mixing each of the fluxes having each composition shown in Examples 1 to 50 and each of the solder powders having each alloy composition shown in Test Examples 1 to 108, the viscosity is increased with time. It can be said that a solder paste that is less likely to change, has excellent wettability, has high mechanical properties, is excellent in solderability, and has improved reliability can be prepared.

Further, in each of the above evaluations, the rosin compound (I) to (V) blended in the flux is also changed to a rosin compound produced from Vietnamese rosin (unhydrogenated rosin). The same results as when (I) to (V) were blended were obtained.

According to the present invention, it is possible to provide a flux for solder paste, which can have low corrosiveness and high reliability.
Further, according to the present invention, it is possible to provide a solder paste which is less likely to change with time such as an increase in viscosity, further suppresses corrosion of the metal surface of the printed circuit board and electronic components, and has excellent solderability.

Claims (18)

A rosin compound containing rosin and agatinic acids in an amount of more than 15% by mass and 70% by mass or less. A flux containing the rosin compound according to claim 1. The flux according to claim 2, further containing a thixotropic agent and a solvent. The flux according to claim 3, wherein the thixotropy contains at least one selected from the group consisting of an amide compound and an ester compound. The flux according to claim 4, wherein the amide compound contains at least one selected from the group consisting of polyamide, bisamide and monoamide. The flux according to claim 4 or 5, wherein the thixo agent contains at least the amide compound and contains the amide compound in an amount of more than 0% by mass and 15% by mass or less based on the total amount of the flux. The flux according to any one of claims 4 to 6, wherein the ester compound contains castor oil. The flux according to any one of claims 4 to 7, wherein the thixo agent contains at least the ester compound and contains the ester compound in an amount of more than 0% by mass and 8% by mass or less based on the total amount of the flux. The flux according to any one of claims 2 to 8, further comprising an organic acid in an amount of 0% by mass or more and 15% by mass or less based on the total amount of the entire flux. Further, the amine is 0% by mass or more and 8% by mass or less, the organic halogen compound is 0% by mass or more and 8% by mass or less, and the amine halide hydroxide is 0% by mass or more and 3% by mass or less based on the total amount of the entire flux. , Or the flux according to any one of claims 2 to 9, which contains an antioxidant in an amount of 0% by mass or more and 8% by mass or less. A solder paste containing the flux according to any one of claims 2 to 10 and a solder powder. The solder powder is at least one of As: 25 to 300 mass ppm, Pb: 0 mass ppm and 5100 mass ppm or less, Sb: 0 mass ppm and 3000 mass ppm or less, and Bi: 0 mass ppm and 10000 mass ppm or less. The solder paste according to claim 11, further comprising a solder alloy having an alloy composition in which the balance is Sn, and satisfying the following equations (1) and (2).
275 ≦ 2As + Sb + Bi + Pb (1)
0.01 ≦ (2As + Sb) / (Bi + Pb) ≦ 10.00 (2)
In the above equations (1) and (2), As, Sb, Bi and Pb each represent the content (mass ppm) in the alloy composition. The solder paste according to claim 12, wherein the alloy composition satisfies the following formula (1a).
275 ≦ 2As + Sb + Bi + Pb ≦ 25200 (1a)
In the above formula (1a), As, Sb, Bi and Pb each represent the content (mass ppm) in the alloy composition. The solder paste according to claim 12, wherein the alloy composition satisfies the following formula (1b).
275 ≦ 2As + Sb + Bi + Pb ≦ 5300 (1b)
In the above formula (1b), As, Sb, Bi and Pb each represent the content (mass ppm) in the alloy composition. The solder paste according to any one of claims 12 to 14, wherein the alloy composition satisfies the following formula (2a).
0.31 ≦ (2As + Sb) / (Bi + Pb) ≦ 10.00 (2a)
In the above formula (2a), As, Sb, Bi and Pb each represent the content (mass ppm) in the alloy composition. Further, the invention according to any one of claims 12 to 15, wherein the alloy composition contains at least one selected from the group consisting of Ag: 0 to 4% by mass and Cu: 0 to 0.9% by mass. Solder paste. A method for producing a rosin compound, which comprises the following steps (a) and (b).
Step (a): A step of distilling a raw material rosin compound containing agatic acids of 1% by mass or more and 15% by mass or less to concentrate the agatic acids in the raw material rosin compound Step (b): After the step (a) The step of distilling and purifying a crude rosin compound containing concentrated agatinic acids to obtain a rosin compound containing more than 15% by mass and 70% by mass or less of agatinic acids. The method for producing a rosin compound according to claim 17, wherein in the step (a), the raw material rosin compound selected from the group consisting of natural rosin and hydrogenated rosin is used.