CN113811420B

CN113811420B - Flux composition comprising maleic acid-modified rosin ester or maleic acid-modified rosin amide, and flux and solder paste comprising the same

Info

Publication number: CN113811420B
Application number: CN202080034898.8A
Authority: CN
Inventors: 川崎浩由; 白鸟正人; 桥本裕; 宫城奈菜子
Original assignee: Senju Metal Industry Co Ltd
Current assignee: Senju Metal Industry Co Ltd
Priority date: 2019-05-27
Filing date: 2020-05-27
Publication date: 2023-05-05
Anticipated expiration: 2040-05-27
Also published as: TW202120636A; CN113811420A; TWI836084B

Abstract

The purpose of the present invention is to provide: a soldering flux which suppresses residual cracking of a flux residue and is excellent in solder wettability. The present invention provides a composition for soldering flux, comprising: 1 or more selected from the group consisting of a maleic acid-modified rosin ester, a maleic acid-modified rosin amide, a hydride of the maleic acid-modified rosin ester, and a hydride of the maleic acid-modified rosin amide.

Description

Flux composition comprising maleic acid-modified rosin ester or maleic acid-modified rosin amide, and flux and solder paste comprising the same

Technical Field

The present invention relates to: a composition for a soldering flux comprising a maleic acid-modified rosin ester or a maleic acid-modified rosin amide, and a soldering flux comprising the same, and a solder paste.

Background

The fixing and electrical connection of electronic components to electronic components in electronic devices, such as the mounting of electronic components to printed substrates, is generally performed by soldering, which is most advantageous in terms of cost and reliability.

The method generally adopted in the soldering is as follows: a flow soldering method in which a molten solder is brought into contact with a printed board and an electronic component to perform soldering, and a reflow soldering method in which solder paste, a preform tab or solder balls are remelted in a reflow furnace to perform soldering.

In the soldering, an auxiliary agent, that is, a flux, which facilitates adhesion of the solder to the printed board and the electronic component is used. The flux exerts (1) a metal surface cleaning action (action of chemically removing an oxide film on a metal surface of a printed board and an electronic component to thereby enable soldering to clean the surface), (2) a re-oxidation-resistant action (action of covering the cleaned metal surface to block contact with oxygen and prevent re-oxidation of the metal surface by heating in soldering), and (3) an interfacial tension lowering action (action of reducing a surface tension of the solder after melting and improving wettability of the metal surface based on the solder) and other useful actions.

Patent document 1 describes the following scheme: a rosin derivative compound obtained by dehydrating and condensing a rosin-based carboxyl group-containing resin and a dimer acid derivative flexible alcohol compound is used as a flux for soldering.

Further, patent document 2 discloses a method for producing a rosin ester with a high yield in a short time.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2014-185298

Patent document 2: japanese patent laid-open No. 2017-186324

Disclosure of Invention

Problems to be solved by the invention

However, the flux described in patent document 1 has poor reliability because residue cracks occur in the flux residue after soldering.

On the other hand, when the rosin ester described in patent document 2 is used as a flux, there are problems that the activity is low and the wettability of the solder is poor.

In view of the above, an object of the present invention is to provide: a soldering flux which suppresses residual cracking of a flux residue and is excellent in solder wettability.

Solution for solving the problem

The present inventors have conducted intensive studies to solve the above problems, and as a result, found that: the present invention has been completed by solving the above problems by using a flux composition containing 1 or more selected from the group consisting of a maleic acid-modified rosin ester, a maleic acid-modified rosin amide, a hydride of the above maleic acid-modified rosin ester, and a hydride of the above maleic acid-modified rosin amide. Namely, the present invention is as follows.

[1]

A composition for a soldering flux comprising: 1 or more selected from the group consisting of a maleic acid-modified rosin ester, a maleic acid-modified rosin amide, a hydride of the maleic acid-modified rosin ester, and a hydride of the maleic acid-modified rosin amide.

[2]

The composition for soldering according to the above [1], wherein the maleic acid-modified rosin ester or the maleic acid-modified rosin amide is 1 or more selected from the group consisting of compounds represented by the following formulas (1) to (7).

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(wherein R 'each independently represents an optionally substituted, linear or branched alkyl group, an alkylene glycol group, or a terminal-modified polyalkylene oxide group; R' each independently represents an optionally substituted, linear or branched alkylene group, or a 2-valent alkylene glycol group.)

[3]

A flux for soldering a solder alloy, which comprises the composition for a flux described in the above [1] or [2 ].

[4]

The flux according to the above [3], wherein the content of the maleic acid-modified rosin ester and/or the maleic acid-modified rosin amide is more than 0% by weight and 60% by weight or less relative to the whole flux.

[5]

The flux according to the above [3] or [4], wherein the flux further comprises a thixotropic agent.

[6]

The flux according to any one of the above [3] to [5], wherein,

the foregoing flux further comprises:

0 to 20% by weight of an amine,

An organic halogen compound in an amount of 0 to 5 wt%

0 to 2 wt% of an amine hydrohalate, or

0 to 5% by weight of an antioxidant,

0 to 80% by weight of a resin.

[7]

A solder paste, comprising: the flux according to any one of the above [3] to [6], and a solder alloy.

[8]

The solder paste according to the above [7], wherein,

the solder alloy has the following alloy composition:

as:25 to 300 mass ppm, bi:0 mass ppm or more and 25000 mass ppm or less, pb: more than 0 mass ppm and 8000 mass ppm or less, and the balance being Sn, and satisfying the following formulas (1) and (2):

275≤2As+Bi+Pb (1)

0<2.3×10 ^-4 ×Bi+8.2×10 ^-4 ×Pb≤7 (2)

[ in the above formulas (1) and (2), as, bi and Pb represent the contents (mass ppm) in the aforementioned alloy compositions, respectively ].

[9]

The solder paste according to the above [7], wherein,

the solder alloy has the following alloy composition:

as:25 to 300 mass ppm; pb: more than 0 mass ppm and less than 5100 mass ppm; sb: more than 0 mass ppm and 3000 mass ppm or less and Bi: at least 1 of more than 0 mass ppm and 10000 mass ppm or less; the balance is composed of Sn, and satisfies the following formulas (3) and (4):

275≤2As+Sb+Bi+Pb (3)

0.01≤(2As+Sb)/(Bi+Pb)≤10.00(4)

[ in the above formulas (3) and (4), as, sb, bi and Pb represent the content (mass ppm) in the composition of the aforementioned alloy, respectively ].

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, there may be provided: a soldering flux which suppresses residual cracking of a flux residue and is excellent in solder wettability.

Detailed Description

Hereinafter, embodiments of the present invention (hereinafter, referred to as "the present embodiment") will be described in detail, but the present invention is not limited thereto, and various modifications may be made without departing from the gist thereof.

Soldering flux

The flux for soldering the solder alloy of the present embodiment contains: a flux composition comprising 1 or more selected from the group consisting of a maleic acid-modified rosin ester, a maleic acid-modified rosin amide, a hydride of the maleic acid-modified rosin ester, and a hydride of the maleic acid-modified rosin amide; and, a solvent.

By using the composition for a flux of the present embodiment, it is possible to sufficiently suppress residue cracking of the flux residue and improve solder wettability. Soldering may be used for either of flow soldering and reflow soldering, but is preferably used for reflow soldering in order for the effect of the present invention to become more remarkable.

[ maleic acid-modified rosin ester/maleic acid-modified rosin amide ]

The flux composition of the present embodiment includes: 1 or more selected from the group consisting of a maleic acid-modified rosin ester, a maleic acid-modified rosin amide, a hydride of the maleic acid-modified rosin ester, and a hydride of the maleic acid-modified rosin amide.

The maleic acid-modified rosin ester is not particularly limited, and examples thereof include: maleic acid-modified rosin monoesters such as maleic acid-modified rosin monomethyl ester, maleic acid-modified rosin monoethyl ester, maleic acid-modified rosin monoisopropyl ester and maleic acid-modified rosin monoethyl glycol ester; and maleic acid-modified rosin diesters such as maleic acid-modified rosin dimethyl esters. Among them, from the viewpoints of flux activity and compatibility, monoester of carboxylic acid residue is preferable, and isopropyl ester is particularly preferable.

Examples of the maleic acid-modified rosin ester include compounds represented by the following formula (1) or (2).

(wherein R represents an optionally substituted, linear or branched alkyl group, an alkylene glycol group, or a terminal modified polyalkylene oxide group.)

Wherein the alkylene glycol group represents a 1-valent group represented by the following formula (i), wherein R ¹ Each independently represents a straight-chain or branched alkylene group having 1 to 4 carbon atoms, and n represents an integer of 1 to 500.

h(OR ¹ ) _n - (i)

The terminal-modified polyalkylene oxide group represents a 1-valent group represented by the following formula (ii), wherein R ¹ Each independently represents a linear or branched alkylene group having 1 to 4 carbon atoms, X represents an amino group, a linear or branched alkyl ester group having 1 to 40 carbon atoms, or a linear or branched alkyl ether group having 1 to 40 carbon atoms, and n represents an integer of 0 to 500.

X-R ¹ -(OR ¹ ) _n - (ii)

The carbon number of the alkyl group represented by R is not particularly limited, and is preferably 1 to 54. The alkylene glycol group represented by R and the carbon number of the terminal-modified polyalkylene oxide group are not particularly limited, and preferably 1 to 500. In the formulae (i) and (ii), the alkyl group of X preferably has 1 to 24 carbon atoms, and R ¹ The carbon number of (2) is preferably 1 to 3. In the formulae (i) and (ii), n is preferably 1 to 500, more preferably 1 to 100, and further preferably 1 to 10. Examples of the terminal-modified polyalkylene oxide group include: a group obtained by adding cetyl alcohol, stearyl alcohol, behenyl alcohol or a C1-40 alcohol such as palmitic acid, stearic acid or behenic acid, or a C1-40 carboxylic acid to the hydroxyl end of a polyalkylene glycol such as polyethylene glycol, polypropylene glycol or a copolymer of ethylene oxide and propylene oxide; and groups obtained by modifying the hydroxyl end of polyalkylene glycol such as a copolymer of ethylene oxide and propylene oxide with an amino group.

The maleic acid-modified rosin ester also includes: and a compound obtained by condensing 2 or more kinds of maleic acid-modified rosin esters such as a dimer of a maleic acid-modified rosin ester and a polymer of a maleic acid-modified rosin ester represented by the following formula (3) or by bonding them with an alcohol or the like.

(wherein R' represents an optionally substituted, linear or branched alkylene group, or a 2-valent alkylene glycol group.)

Wherein the alkylene glycol group having a valence of 2 represents a valence of 2 represented by the following formula (iii), wherein R ² And R is ³ Each independently represents a straight-chain or branched alkylene group having 1 to 4 carbon atoms, and n represents an integer of 0 to 500.

-R ² -(OR ³ ) _n - (iii)

The carbon number of the alkylene group represented by R' is not particularly limited, and is preferably 1 to 54. The carbon number of the 2-valent alkylene glycol group represented by R' is not particularly limited, and is preferably 1 to 500. In the formula (iii), R is ² And R is ³ Carbon number of (2)Preferably 1 to 3. In the formula (iii), n is preferably 1 to 500, more preferably 1 to 100, and further preferably 1 to 10.

The maleic acid-modified rosin amide is not particularly limited, and examples thereof include a dehydration condensate of maleic acid-modified rosin and cyclohexylamine, and a cyclohexylamine salt of a dehydration condensate of maleic acid-modified rosin and cyclohexylamine. Specifically, examples thereof include compounds represented by the following formulas (4) and (5). Among them, maleic acid-modified rosin monocyclohexyl amide and maleic acid-modified hydrogenated rosin cyclohexyl amide are preferable from the viewpoints of flux activity and compatibility.

(wherein R is as defined above.)

In addition, the maleic acid-modified rosin amide further comprises: a compound obtained by condensing 2 or more kinds of maleic acid-modified rosin amide represented by the following formula (6) or a combination thereof via an amine or the like, such as a maleic acid-modified rosin amide dimer or a maleic acid-modified rosin amide polymer.

(wherein R' has the same meaning as described above.)

Further, the maleic acid-modified rosin acid amide also includes: a compound obtained by bonding a maleic acid-modified rosin amide represented by the following formula (7) and a maleic acid-modified rosin ester directly or via an amine, an alcohol or the like.

(wherein R' has the same meaning as described above.)

In addition, the maleic acid-modified rosin ester and the maleic acid-modified rosin amide also include: various isomers (structural isomers, optical isomers, etc.) of the above-mentioned compounds, salts (amine salts, etc.) of the above-mentioned compounds.

The maleic acid-modified rosin ester and the maleic acid-modified rosin amide may be used alone or in combination of 1 or more than 2.

The hydrides of the maleic acid-modified rosin esters and the maleic acid-modified rosin amides refer to compounds in which the carbon-carbon double bonds present in these compounds are hydrogenated. For example, the hydrogenated product of the maleic acid-modified rosin ester represented by the above formula (1) has a structure represented by the following formula (8).

(wherein R is as defined above.)

The various maleic acid-modified rosin esters and maleic acid-modified rosin amides can be produced by a known method. As a known method, for example, it is possible to employ: the solvent-free reaction described in example 1 of Japanese patent application laid-open No. 2017-186324 and the reaction in the hydrophobic solvent of example 6. Examples of raw rosin used for the synthesis of the maleic acid-modified rosin ester and the maleic acid-modified rosin amide include gum rosin, tall oil rosin, wood rosin, and purified products thereof (purified rosin). As the raw rosin, raw rosin and commercially available gum rosin described in "DF.Zinkel, J.Russell Jigao Gu Chuanji Hongchi (1993), chemical production, chemical use, 361-362" of pine can be used, for example. That is, the maleic acid-modified rosin ester and the maleic acid-modified rosin amide of the present embodiment may contain compounds obtained by esterifying or amidating the above-described various raw material rosins and rosin derivatives obtained from raw material rosins such as (hydrogenated) maleic acid-modified rosins.

The content of the maleic acid-modified rosin ester and the maleic acid-modified rosin amide is preferably more than 0% by weight and 60% by weight or less, more preferably 5% by weight or more, still more preferably 10% by weight or more, still more preferably 20% by weight or more, particularly preferably 30% by weight or more, and as an upper limit, more preferably 50% by weight or less, still more preferably 40% by weight or less, relative to the whole flux. The greater the content of the maleic acid-modified rosin ester and the maleic acid-modified rosin amide, the more remarkable the suppression effect of the residue cracking of the flux residue tends to be.

The flux of the present embodiment may contain resins other than the above-described maleic acid-modified rosin ester and maleic acid-modified rosin amide, and their hydrides. As the resin, various resins used in conventional soldering fluxes can be used. Examples of such resins include rosin-based resins, acrylic resins, polyesters, polyethylenes, polypropylenes, polyamides, styrene-maleic acid copolymers, acrylic resins, epoxy resins, phenolic resins, phenoxy resins, terpene phenolic resins, and mixtures thereof, and among these, rosin-based resins are often used. Examples of the rosin-based resin include natural rosins such as gum rosin and wood rosin, and derivatives thereof (polymerized rosin, hydrogenated rosin, disproportionated rosin, acid-modified rosin, rosin ester, and the like).

The content of the resin in the flux is not limited, and when the flux is used as a reflow flux, the content may be, for example, 10 to 80 wt%, 20 to 70 wt%, or 30 to 60 wt%. When the flux is used for flow soldering, it may be in the range of 3 to 18 wt%, 6 to 15 wt%, or 9 to 12 wt%, for example.

Examples of the solvent contained in the flux of the present embodiment include water, alcohol solvents, glycol ether solvents, terpineols, and the like. As the alcohol-based solvent, a solvent, examples thereof include isopropanol, 1, 2-butanediol, isobornyl cyclohexanol, 2, 4-diethyl-1, 5-pentanediol, 2-dimethyl-1, 3-propanediol, 2, 5-dimethyl-2, 5-hexanediol, 2, 5-dimethyl-3-hexyne-2, 5-diol, 2, 3-dimethyl-2, 3-butanediol, 1-tris (hydroxymethyl) ethane, 2-ethyl-2-hydroxymethyl-1, 3-propanediol, 2' -oxybis (methylene) bis (2-ethyl-1, 3-propanediol) 2, 2-bis (hydroxymethyl) -1, 3-propanediol, 1,2, 6-trihydroxyhexane, bis [2, 2-tris (hydroxymethyl) ethyl ] ether, 1-ethynyl-1-cyclohexanol, 1, 4-cyclohexanediol, 1, 4-cyclohexanedimethanol, erythritol, threitol, guaifenesin, 3, 6-dimethyl-4-octyne-3, 6-diol, 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol, and the like. Examples of the glycol ether solvent include hexyldiglycol, diethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether, 2-methylpentane-2, 4-diol, diethylene glycol monohexyl ether, diethylene glycol dibutyl ether, triethylene glycol monobutyl ether, and tetraethylene glycol monomethyl ether.

The flux of the present embodiment may further contain an organic acid, an amine, a halogen (an organic halogen compound, an amine hydrohalate) as an active agent.

When the flux according to the present embodiment is used as a flux for reflow soldering, it preferably contains 0 wt% or more and 10 wt% or less of an organic acid. When the flux according to the present embodiment is used as a flux for reflow soldering, the flux contains preferably 0 wt% or more and 20 wt% or less of amine, and more preferably 0 wt% or more and 5 wt% or less of amine. When the flux according to the present embodiment is used as a flux for reflow soldering, the halogen is preferably an organic halogen compound in an amount of 0 wt% or more and 5 wt% or less, and preferably an amine halogen acid salt in an amount of 0 wt% or more and 2 wt% or less.

When the flux according to the present embodiment is used as a flux for flow soldering, the flux preferably contains 0.1 wt% or more and 12.0 wt% or less of an active agent, more preferably contains 0.3 wt% or more and 8.0 wt% or less, and still more preferably contains 0.5 wt% or more and 4.0 wt% or less.

Examples of the organic acid include glutaric acid, adipic acid, azelaic acid, eicosanedioic acid, citric acid, glycolic acid, succinic acid, salicylic acid, diglycolic acid, dipicolinic acid, dibutylanilinedioic acid, suberic acid, sebacic acid, thioglycolic acid, terephthalic acid, dodecanedioic acid, p-hydroxyphenylacetic acid, phenylsuccinic acid, phthalic acid, fumaric acid, maleic acid, malonic acid, lauric acid, benzoic acid, tartaric acid, tris (2-carboxyethyl) isocyanurate, glycine, 1, 3-cyclohexanedicarboxylic acid, 2-bis (hydroxymethyl) propionic acid, 2-bis (hydroxymethyl) butyric acid, 2, 3-dihydroxybenzoic acid, 2, 4-diethylglutaric acid, 2-quinolinecarboxylic 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 hydride of dimer acid to which hydrogen is added, and hydrogenated trimer acid which is a hydride of trimer acid to which hydrogen is added.

Examples thereof include: the reactants of oleic acid and linoleic acid, i.e., dimer acid, the reactants of acrylic acid, i.e., trimer acid, the reactants of methacrylic acid, i.e., dimer acid, the reactants of acrylic acid and methacrylic acid, i.e., trimer acid, the reactants of acrylic acid and methacrylic acid, i.e., dimer acid, the reactants of oleic acid, i.e., trimer acid, the reactants of linoleic acid, i.e., dimer acid, the reactants of linoleic acid, i.e., trimer acid, the reactants of linolenic acid, i.e., dimer acid, the reactants of acrylic acid and oleic acid, i.e., dimer acid, the reactants of acrylic acid and linoleic acid, i.e., trimer acid the reaction product of acrylic acid and linolenic acid is dimer acid, the reaction product of acrylic acid and linolenic acid is trimer acid, the reaction product of methacrylic acid and oleic acid is dimer acid, the reaction product of methacrylic acid and oleic acid is trimer acid, the reaction product of methacrylic acid and linoleic acid is dimer acid, the reaction product of methacrylic acid and linoleic acid is trimer acid, the reaction product of methacrylic acid and linolenic acid is dimer acid, the reaction product of methacrylic acid and linolenic acid is trimer acid, the reaction product of oleic acid and linolenic acid is dimer acid, the reaction product of oleic acid and linolenic acid is trimer acid, the reaction product of linoleic acid and linolenic acid is dimer acid, the reaction product of linoleic acid and linolenic acid is trimer acid, the hydrogenation product of each dimer acid is hydrogenation dimer acid, the hydrogenation product of each trimer acid is hydrogenation trimer acid, and the like.

Examples of the amine include: monoethanolamine, diphenylguanidine, xylylguanidine, ethylamine, triethylamine, cyclohexylamine, ethylenediamine, triethylenetetramine, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1, 2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 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 isocyanurate adduct, 2-phenylimidazole isocyanuric acid adducts, 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-phenylimidazoline, 2, 4-diamino-6-vinyl-s-triazine isocyanuric acid adducts, 2, 4-diamino-6-methacryloyloxyethyl-s-triazine, epoxy-imidazole adducts, 2-methylbenzimidazole, 2-octylbenzimidazole, 2-pentylbenzoimidazole, 2- (1-ethylpentyl) benzimidazole, 2-nonylbenzimidazole, 2- (4-thiazolyl) benzimidazole, 2- (2 ' -hydroxy-5 ' -methylphenyl) benzotriazole, 2- (2 ' -hydroxy-3 ' -tert-butyl-5 ' -methylphenyl) -5-chlorobenzotriazole, 2- (2 ' -hydroxy-3 ',5' -di-tert-phenyl) benzotriazole, tert-2- (2-hydroxy-5 ' -tert-phenyl) benzotriazole, tert-octyl-benzotriazole, 2,2 '-methylenebis [6- (2H-benzotriazol-2-yl) -4-tert-octylphenol ], 6- (2-benzotriazolyl) -4-tert-butyl-6' -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' - [ [ (methyl-1H-benzotriazol-1-yl) methyl ] imino ] diethanol, 1- (1 ',2' -dicarboxyethyl) benzotriazole, 1- (2, 3-dicarboxypropyl) benzotriazole, 1- [ (2-ethylhexyl amino) methyl ] benzotriazole, 2, 6-bis [ (1H-benzotriazol-1-yl) methyl ] -4-methylphenol, 5-methylbenzotriazole, 5-phenyltetrazole and the like.

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

Amine hydrohalates are compounds obtained by reacting an amine with a hydrogen halide.

As the amine of the amine hydrohalate, the above-mentioned amine may be used, and examples thereof include ethylamine, cyclohexylamine, ethylenediamine, triethylamine, diphenylguanidine, xylylguanidine, methylimidazole, 2-ethyl-4-methylimidazole and the like. Examples of the hydrogen halide include chlorine, bromine, iodine, and hydrogen fluoride (hydrogen chloride, hydrogen bromide, hydrogen iodide, and hydrogen fluoride). In addition, boron fluoride may be contained in place of or together with the amine halogen acid salt, and as boron fluoride, boron fluoride acid and the like may be mentioned.

Examples of the amine hydrohalate include aniline hydrogen chloride, cyclohexylamine hydrogen chloride, aniline hydrogen bromide, diphenylguanidine hydrogen bromide, xylylguanidine hydrogen bromide, and ethylamine hydrogen bromide.

The flux of the present embodiment may further contain an antioxidant, and examples of the antioxidant include a hindered phenol-based antioxidant, and when used as a reflow flux, the antioxidant is preferably contained in an amount of 0 wt% or more and 5 wt% or less, and when used as a flow flux, the antioxidant is preferably contained in an amount of 0 wt% or more and 5 wt% or less, and more preferably contained in an amount of 0 wt% or more and 2 wt% or less.

The flux of the present embodiment may contain a thixotropic agent.

Examples of the thixotropic agent include wax-based thixotropic agents, amide-based thixotropic agents, sorbitol-based thixotropic agents, and the like. Examples of the wax-based thixotropic agent include hydrogenated castor oil and the like. Examples of the amide-based thixotropic agent include monoamide-based thixotropic agents, bisamide-based thixotropic agents, and polyamide-based thixotropic agents, and specifically include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, saturated fatty acid amide, oleic acid amide, erucic acid amide, unsaturated fatty acid amide, p-toluenemethane amide, aromatic amide, methylenebisstearic acid amide, ethylenebislauric acid amide, ethylenebishydroxystearic acid amide, saturated fatty acid bisamide, methylenebisoleic acid amide, unsaturated fatty acid bisamide, m-xylylenebisstearic acid amide, aromatic bisamide, saturated fatty acid polyamide, unsaturated fatty acid polyamide, aromatic polyamide, substituted amide, methylol stearic acid amide, methylol amide, fatty acid ester amide, and the like. Examples of the sorbitol thixotropic agent include dibenzylidene-D-sorbitol, bis (4-methylbenzylidene) -D-sorbitol, and the like.

In addition, the flux of the present embodiment may contain an ester compound as a thixotropic agent. Examples of the ester compound include hydrogenated castor oil and the like.

When the total amount of the thixotropic agent contained in the flux is used as the reflow flux, it is preferably 0 wt% or more and 15 wt% or less, more preferably 0 wt% or more and 10 wt% or less. In addition, when the amide thixotropic agent is used as a reflow soldering flux, the content of the ester compound is preferably 0 wt% or more and 8.0 wt% or less, more preferably 0 wt% or more and 4.0 wt% or less.

When the total amount of the thixotropic agent contained in the flux is used as the flux, it is preferably 0 wt% or more and 3 wt% or less, more preferably 0 wt% or more and 1 wt% or less.

[ solder paste ]

The flux of the present embodiment may be used for both flow soldering and reflow soldering, but is preferably used for reflow soldering in order to make the effect of the present invention more remarkable.

The solder paste of embodiment 1 includes: the flux, and the solder alloy.

The solder alloy is not particularly limited, but preferably has the following alloy composition:

275≤2As+Bi+Pb (1)

0<2.3×10 ^-4 ×Bi+8.2×10 ^-4 ×Pb≤7 (2)

The solder alloy according to embodiment 2 is not particularly limited, but preferably has the following alloy composition:

as:25 to 300 mass ppm, pb: more than 0 mass ppm and 5100 mass ppm or less, and Sb: more than 0 mass ppm and 3000 mass ppm or less and Bi: at least 1 of more than 0 mass ppm and 10000 mass ppm or less, the balance being composed of Sn, and satisfying the following formulas (3) and (4):

275≤2As+Sb+Bi+Pb (3)

0.01≤(2As+Sb)/(Bi+Pb)≤10.00 (4)

As is an element that can suppress the change with time of the viscosity of the solder paste. As has low reactivity with flux and is an element more expensive than Sn, and therefore, it is presumed that thickening inhibition effect can be exerted. If As is less than 25 mass ppm, the thickening inhibition effect cannot be sufficiently exhibited. The lower limit of the As content is 25 mass ppm or more, preferably 50 mass ppm or more, more preferably 100 mass ppm or more. On the other hand, if As is excessive, 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, more preferably 200 mass ppm or less.

Sb is an element having low reactivity with the flux and showing a thickening suppression effect. When the solder alloy of the present embodiment contains Sb, the lower limit of the Sb content exceeds 0 mass ppm, preferably 25 mass ppm or more, more preferably 50 mass ppm or more, still more preferably 100 mass ppm or more, particularly preferably 300 mass ppm or more. On the other hand, if the Sb content is too large, wettability is deteriorated, and therefore, the content must be moderate. The upper limit of the Sb content is 3000 mass ppm or less, preferably 1150 mass ppm or less, more preferably 500 mass ppm or less.

Bi and Pb are elements having low reactivity with flux and showing thickening inhibition effect, similarly to Sb. In addition, bi and Pb are elements that can suppress deterioration of wettability based on As by lowering the liquidus temperature of the solder alloy.

If at least 1 element of Sb, bi, and Pb is present, deterioration of wettability based on As can be suppressed. When the solder alloy of the present embodiment contains Bi, the lower limit of the Bi content exceeds 0 mass ppm, preferably 25 mass ppm or more, more preferably 50 mass ppm or more, still more preferably 75 mass ppm or more, particularly preferably 100 mass ppm or more, and most preferably 250 mass ppm or more. When the solder alloy of the present embodiment contains Pb, the lower limit of the Pb content exceeds 0 mass ppm, preferably 25 mass ppm or more, more preferably 50 mass ppm or more, still more preferably 75 mass ppm or more, particularly preferably 100 mass ppm or more, and most preferably 250 mass ppm or more.

On the other hand, if the content of these elements is too large, the solidus temperature is significantly lowered, and therefore the temperature difference between the liquidus temperature and the solidus temperature, i.e., Δt, becomes excessively large. If Δt is excessively large, a high-melting-point crystal phase having a small content of Bi and Pb is precipitated during solidification of the molten solder, and therefore Bi and Pb in the liquid phase are concentrated. Then, if the temperature of the molten solder is further lowered, the low-melting-point crystal phase having a high concentration of Bi and Pb segregates. Therefore, the mechanical strength and the like of the solder alloy deteriorate, and the reliability deteriorates. In particular, since the crystal phase having a high Bi concentration is hard and brittle, if segregation occurs in the solder alloy, mechanical strength and the like are significantly reduced.

From this viewpoint, in the case where the solder alloy of the present embodiment contains Bi, the upper limit of the Bi content is 25000 mass ppm or less, preferably 10000 mass ppm or less, more preferably 1000 mass ppm or less, still more preferably 600 mass ppm or less, and particularly preferably 500 mass ppm or less. When the solder alloy of the present embodiment contains Pb, the upper limit value of the Pb content is 8000 mass ppm or less, preferably 5100 mass ppm or less, more preferably 5000 mass ppm or less, still more preferably 1000 mass ppm or less, particularly preferably 850 mass ppm or less, and most preferably 500 mass ppm or less.

The solder alloy according to embodiment 1 preferably satisfies the following formula (1).

275≤2As+Bi+Pb (1)

In the above formula (1), as, bi and Pb represent the contents (mass ppm) in the alloy composition, respectively.

As, bi and Pb are elements showing thickening inhibition effect. The total amount of these is preferably 230 mass ppm or more. (1) In the formula, the reason why the As content is 2 times is that As has a higher thickening inhibition effect than Bi and Pb.

(1) If the formula is less than 275, the thickening inhibition effect cannot be sufficiently exhibited. (1) The lower limit of the formula is 275 or more, preferably 300 or more, more preferably 700 or more, and still more preferably 900 or more. On the other hand, the upper limit of (1) is not particularly limited from the viewpoint of the thickening inhibition effect, but is preferably 25200 or less, more preferably 15200 or less, further preferably 10200 or less, particularly preferably 8200 or less, and most preferably 5300 or less from the viewpoint of forming a range suitable for Δt.

The upper limit and the lower limit are appropriately selected from the above preferred embodiments, and are the following formulas (1 a) and (1 b).

275≤2As+Bi+Pb≤25200 (1a)

275≤2As+Bi+Pb≤5300 (1b)

In the above formulas (1 a) and (1 b), as, bi and Pb represent the contents (mass ppm) in the alloy composition, respectively.

The solder alloy according to embodiment 1 preferably satisfies the following formula (2).

0<2.3×10 ^-4 ×Bi+8.2×10 ^-4 ×Pb≤7 (2)

In the above formula (2), bi and Pb represent the contents (mass ppm) in the alloy composition, respectively.

Bi and Pb suppress deterioration of wettability due to the inclusion of As, but if the content is too large, deltaT increases, and therefore strict management is required. In particular, in the alloy composition containing both Bi and Pb, ΔT tends to be increased. In embodiment 1, the total of values obtained by multiplying the contents of Bi and Pb by a predetermined coefficient is limited, whereby the increase in Δt can be suppressed. In the formula (2), the coefficient of Pb is larger than that of Bi. This is because Pb contributes significantly to Δt as compared with Bi, and only a slight increase in the content greatly increases Δt.

(2) The solder alloy having the formula 0 does not contain two elements of Bi and Pb, and deterioration of wettability due to the inclusion of As cannot be suppressed. (2) The lower limit of the formula exceeds 0, preferably 0.02 or more, more preferably 0.03 or more, still more preferably 0.05 or more, particularly preferably 0.06 or more, and most preferably 0.11 or more. On the other hand, if the formula (2) exceeds 7, the temperature range of Δt becomes excessively wide, so that the molten solder is segregated in a crystal phase having high concentrations of Bi and Pb at the time of solidification, and the mechanical strength and the like are deteriorated. (2) The upper limit of (c) is 7 or less, preferably 6.56 or less, more preferably 6.40 or less, still more preferably 5.75 or less, still more preferably 4.18 or less, particularly preferably 2.30 or less, and most preferably 0.90 or less.

The upper limit and the lower limit are appropriately selected from the above preferred embodiments and are represented by the following formula (2 a).

0.02≤2.3×10 ^-4 ×Bi+8.2×10 ^-4 ×Pb≤0.9(2a)

In the above formula (2 a), bi and Pb represent the content (mass ppm) in the alloy composition, respectively.

The solder alloy according to embodiment 2 preferably satisfies the following formula (3).

275≤2As+Sb+Bi+Pb (3)

In the above formula (3), as, sb, bi and Pb represent the contents (mass ppm) in the alloy composition, respectively.

As, sb, bi and Pb are elements showing thickening inhibition effects. The total of these must be 275 mass ppm or more. (3) In the formula, the reason why the As content is 2 times is that As has a higher thickening inhibition effect than Sb, bi, and Pb.

(1) If the formula is less than 275, the thickening inhibition effect cannot be sufficiently exhibited. (1) The lower limit of the formula is 275 or more, preferably 350 or more, more preferably 1200 or more. On the other hand, the upper limit of (1) is not particularly limited from the viewpoint of the thickening inhibition effect, but is preferably 25200 or less, more preferably 10200 or less, further preferably 5300 or less, and particularly preferably 3800 or less from the viewpoint of forming a range suitable for Δt.

The upper limit and the lower limit are appropriately selected from the above preferred embodiments, and are the following formulas (3 a) and (3 b).

275≤2As+Sb+Bi+Pb≤25200 (3a)

275≤2As+Sb+Bi+Pb≤5300 (3b)

In the above formulas (3 a) and (3 b), as, sb, bi, and Pb represent the contents (mass ppm) in the alloy composition, respectively.

The solder alloy according to embodiment 2 preferably satisfies the following formula (4).

0.01≤(2As+Sb)/(Bi+Pb)≤10.00 (4)

In the above formula (2), as, sb, bi and Pb represent the contents (mass ppm) in the alloy composition, respectively.

If the contents of As and Sb are large, wettability of the solder alloy is deteriorated. On the other hand, bi and Pb suppress deterioration of wettability due to inclusion of As, but if the content is excessive, Δt increases, and therefore strict management is required. In particular, in the alloy composition containing both Bi and Pb, Δt is liable to rise. In view of this, Δt is enlarged when the content of Bi and Pb is increased to excessively improve wettability. On the other hand, if the contents of As and Sb are increased to improve the thickening suppression effect, the wettability is deteriorated. Therefore, in embodiment 2, when the total amount of the two groups is within a proper predetermined range, the thickening suppression effect, the narrowing of Δt, and the wettability are all satisfied at the same time.

(4) If the formula is less than 0.01, the total content of Bi and Pb becomes relatively large As compared with the total content of As and Pb, and therefore, deltaT is enlarged. (4) The lower limit of the formula is 0.01 or more, preferably 0.02 or more, more preferably 0.41 or more, still more preferably 0.90 or more, particularly preferably 1.00 or more, and most preferably 1.40 or more. On the other hand, if the formula (4) exceeds 10.00, the total of the contents of As and Sb is relatively large As compared with the total of the contents of Bi and Pb, and therefore, wettability is deteriorated. (4) The upper limit of (2) is 10.00 or less, preferably 5.33 or less, more preferably 4.50 or less, still more preferably 2.67 or less, still more preferably 4.18 or less, and particularly preferably 2.30 or less.

The denominator of the formula (4) is "bi+pb", and if these are not contained, the formula (4) is not established. That is, the solder alloy of embodiment 2 must contain at least 1 of Bi and Pb. As described above, the wettability of the alloy composition containing no Bi and Pb is poor.

The upper limit and the lower limit are appropriately selected from the above preferred embodiments and are represented by the following formula (4 a).

0.31≤(2As+Sb)/(Bi+Pb)≤10.00 (4a)

In the above formula (4 a), as, sb, bi and Pb represent the contents (mass ppm) in the alloy composition, respectively.

Ag is formed at grain boundary ₃ Sn, any element that can improve the reliability, mechanical strength, and the like of the solder alloy. Ag is an element having a higher ionization tendency than Sn, and is present together with As, pb, and Bi, thereby contributing to the thickening suppression effect thereof. The Ag content is preferably 0 to 4%, more preferably 0.5 to 3.5%, and still more preferably 1.0 to 3.0%.

Cu is an arbitrary element that can improve the joining strength of the soldered joint. Cu is an element having a higher ionization tendency than Sn, and is present together with As, pb, and Bi, thereby contributing to the thickening suppression effect thereof. The Cu content is preferably 0 to 0.9%, more preferably 0.1 to 0.8%, and still more preferably 0.2 to 0.7%.

The balance of the solder alloy of the present embodiment is Sn. Unavoidable impurities may be contained in addition to the aforementioned elements. Even when unavoidable impurities are contained, the aforementioned effects are not affected. As will be described later, the inclusion of the elements not included in the present embodiment as unavoidable impurities does not affect the effects described above. If the content of In is too large, Δt increases, and therefore, if it is 1000 mass ppm or less, the aforementioned effects are not affected.

The content of the solder alloy and the flux in the solder paste is not limited, and for example, the content of the solder alloy may be 5 to 95% by weight and the content of the flux may be 5 to 95% by weight.

The solder paste of the present embodiment preferably contains zirconia powder. Zirconia can suppress the increase in viscosity of the paste with time. This is presumably because the zirconia is contained, so that the oxide film thickness on the surface of the solder powder is maintained in a state before the solder powder is put into the flux. Details are not clear, but are presumed as follows. In general, the active ingredient of the flux remains slightly active even at normal temperature, and therefore, the surface oxide film of the solder powder becomes thin by reduction, which causes aggregation of the powders. It is therefore assumed that: by adding zirconia powder to the solder paste, the active ingredient of the flux preferentially reacts with the zirconia powder, and the extent to which the oxide film on the surface of the solder powder does not aggregate is maintained.

In order to sufficiently exert such an effect, the content of zirconia powder in the solder paste is preferably 0.05 to 20.0% with respect to the total mass of the solder paste. The above-described effect can be exhibited when the content is 0.05% or more, and the thickening-preventing effect can be exhibited when the content is 20.0% or less. The zirconia content is preferably 0.05 to 10.0%, more preferably 0.1 to 3%.

The particle size of the zirconia powder in the solder paste is preferably 5 μm or less. If the particle diameter is 5 μm or less, the printability of the paste can be maintained. The lower limit is not particularly limited as long as it is 0.5 μm or more. The particle size is as follows: SEM pictures of zirconia powder were taken, and the projected equivalent diameter was determined by image analysis for each powder of 0.1 μm or more as an average value thereof.

The shape of the zirconia is not particularly limited, and if the zirconia is in a different shape, the contact area with the flux is large, and the thickening suppression effect is exhibited. If the paste is spherical, good fluidity can be obtained, and therefore, excellent printability as a paste can be obtained. The shape may be appropriately selected according to desired characteristics.

Examples

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the scope of the present invention is not limited thereto.

The fluxes of examples A1 to 45 and comparative examples A1 to 3 were prepared with the compositions shown in tables 1 to 6 below, and the wetting speed of the fluxes was verified by preparing a solder paste using the fluxes.

The composition ratio in the following table is the weight (mass%) of the flux, based on 100 total.

In the solder paste, the flux was 11 wt% and the metal powder was 89 wt%. In addition, the metal powder in the solder paste is as follows: the average particle diameter of the metal powder was 20 μm in a Sn-Ag-Cu-based solder alloy containing 3.0 wt% Ag, 0.5 wt% Cu and the balance Sn.

< investigation of soldering flux >)

(1) Evaluation of solder wettability (wetting speed)

(verification method)

Regarding the wetting rate of the solder paste, a copper plate having a width of 5mm×a length of 25mm×a thickness of 0.5mm was subjected to an oxidation treatment at 150℃for 1 hour according to the method of the arc-shaped tin pick-up test (meniscograph test), and a copper oxide plate as a test plate was obtained, and evaluated as follows using Solder Checker SAT-5200 (manufactured by RHECA) as a test device and Sn-3Ag-0.5Cu (each numerical value is weight%) as a solder.

First, a test board was immersed by 5mm in each of the fluxes of examples and comparative examples measured in a beaker, and the fluxes were coated on the test board. Next, after the flux was applied, the test board coated with the flux was immersed in the solder bath rapidly, and a zero-crossing time (seconds) was obtained. Next, for each flux of examples and comparative examples, 5 measurements were performed, and the average value of the obtained 5 zero crossing times (seconds) was calculated. Test conditions were set as follows.

Speed of impregnation of the drill pipe: 5 mm/sec (JIS Z3198-4:2003)

Depth of impregnation for the drill pipe: 2mm (JIS Z3198-4:2003)

Dipping time for the soft solder groove: 10 seconds (JIS Z3198-4:2003)

Solder bath temperature: 245 ℃ (JIS C60068-2-69:2019)

The shorter the average value of the zero crossing time (sec), the higher the wetting speed, the better the solder wettability.

(determination criterion)

And (2) the following steps: the average value of zero crossing time (seconds) is 6 seconds or less.

X: the average value of zero crossing time (seconds) exceeds 6 seconds.

(2) Evaluation of residue crack suppression

On a substrate having a size of 1.5X0.25 mm and electrode pads 64 arranged at a pitch of 0.4mm, soldering was performed using a reflow oven with a metal mask having a thickness of 0.15mm, printing paste (reflow peak temperature: 240 ℃). After the reflow, the number of cracks in the flux residue between pads was counted after being left for 24 hours or more in a normal temperature environment, and the evaluation was performed as follows.

And (2) the following steps: residue cracks are less than 15

X: more than 15 residues of cracks

The maleic acid-modified rosin ester and the maleic acid-modified rosin amide compound in the table each contain an isomer (structural isomer/stereoisomer) thereof.

TABLE 1

TABLE 2

TABLE 3

TABLE 4

TABLE 5

TABLE 6

The flux of the present embodiment contains 1 or more selected from the group consisting of a maleic acid-modified rosin ester, a maleic acid-modified rosin amide, a hydride of the maleic acid-modified rosin ester, and a hydride of the maleic acid-modified rosin amide, whereby residue cracking of the flux residue is suppressed, and solder wettability is also excellent.

< investigation of solder alloy >

The flux prepared in example A1 was mixed with a solder alloy having an alloy composition shown in tables 7 to 18 and satisfying JIS Z3284-1 to prepare a solder paste: classification of powder size in 2014 (table 2) size of symbol 4 (particle size distribution). The mass ratio of the soldering flux to the soft solder alloy is: solder powder = 11:89. for each solder paste, the change in viscosity with time was measured. In addition, the liquidus temperature and solidus temperature of the solder powder were measured. Further, wettability was evaluated by using the solder paste immediately after the production. Details are described below.

(3) Time-dependent change

For each solder paste immediately after manufacture, manufactured by Malcom co., ltd: PCU-205, at rotational speed: the viscosity was measured at 10rpm at 25℃in the atmosphere for 12 hours. The viscosity after 12 hours was 1.2 times or less as compared with the viscosity after 30 minutes from the production of the solder paste, and the viscosity was evaluated as "o" and the viscosity exceeding 1.2 times as "x" if the thickening inhibition effect was sufficiently obtained.

(4)ΔT

For solder alloys before mixing with flux, use SII NANOTECHNOLOGY inc. Product, model: EXSTAR DSC7020, at sample level: about 30mg, rate of temperature increase: DSC measurements were performed at 15℃per minute to obtain solidus and liquidus temperatures. The solidus temperature is subtracted from the obtained liquidus temperature to determine Δt. Delta T is equal to or less than 10deg.C and equal to or less than 10deg.C.

(5) Wettability of

Printing each solder paste just manufactured on a Cu board, and printing the solder paste on N in a reflow oven ₂ In the atmosphere, the mixture was heated from 25℃to 260℃at a heating rate of 1℃per second, and then cooled to room temperature. The appearance of the solder bump after cooling was observed with an optical microscope, thereby evaluating wettability. The case where the solder powder which was not completely melted was observed was evaluated as "good", and the case where the solder powder which was not completely melted was observed was evaluated as "×".

(6) Comprehensive evaluation

And (2) the following steps: all the above evaluations were good

X: in each of the above evaluations, there were X [ Table 7]

TABLE 8

TABLE 9

TABLE 10

TABLE 11

TABLE 12

TABLE 13

TABLE 14

TABLE 15

TABLE 16

TABLE 17

TABLE 18

As shown in tables 7 to 18, the solder paste containing the flux of example A1 and the solder alloy of example B was evaluated, and as a result, good results were obtained in terms of thickening inhibition effect, deltaT, and wettability in all of examples B (examples B2 to B95; and examples B2-1 to examples B2-108).

In contrast, comparative examples B1, B10, B19, B28, B37 and B46 do not contain As, and therefore, do not exhibit thickening inhibition effects.

Comparative examples B2, B11, B20, B29, B38 and B47 have the formula (1) below the lower limit, and thus cannot exhibit the thickening suppression effect.

The comparative examples B3, B4, B12, B13, B21, B22, B30, B31, B39, B40, B48 and B49 have As contents exceeding the upper limit value, and thus show the result of poor wettability.

The Pb content and formula (2) of comparative examples B5, B7, B9, B14, B16, B18, B23, B25, B27, B32, B34, B36, B41, B43, B45, B50, B52, and B54 exceed the upper limit value, and thus show the result that Δt exceeds 10 ℃.

Comparative examples B6, B15, B24, B33, B42 and B51 have formula (2) exceeding the upper limit value, and thus show the result that Δt exceeds 10 ℃.

The Bi contents and (2) of comparative examples B8, B17, B26, B35, B44 and B53 exceed the upper limit value, and thus show the result that DeltaT exceeds 10 ℃.

Comparative examples B2-1, B2-14, B2-27, B2-40, B2-53 and B2-66 did not contain As, and thus, did not exhibit thickening inhibition effect.

The comparative examples B2-2, B2-15, B2-28, B2-41, B2-54 and B2-67 have the formula (3) below the lower limit, and thus cannot exhibit the thickening inhibition effect.

The comparative examples B2-3, B2-16, B2-29, B2-42, B2-55 and B2-68 have the formula (4) exceeding the upper limit, and thus have poor wettability.

As contents of comparative examples B2-4, B2-5, B2-17, B2-18, B2-30, B2-31, B2-43, B2-44, B2-56, B2-57, B2-69 and B2-70 and formula (4) exceed upper limits, and thus shows the result of poor wettability.

Comparative examples B2-6 to B2-8; b2-19 to B2-21; b2-32 to B2-34; b2-45 to B2-47; b2-58 to B2-60; and B2-71 to B2-73 exceeds the upper limit, and thus, the wettability is poor.

The Bi contents of comparative examples B2-9, B2-10, B2-22, B2-23, B2-35, B2-36, B2-48, B2-49, B2-61, B2-62, B2-74 and B2-75 exceed the upper limit, and thus, the results of having a DeltaT exceeding 10℃are shown.

The Pb contents of comparative examples B2-11, B2-13, B2-24, B2-26, B2-37, B2-39, B2-50, B2-52, B2-63, B2-65, B2-76 and B2-78 exceed the upper limit, and thus, the result that DeltaT exceeds 10℃is shown.

Comparative examples B2-12, B2-25, B2-38, B2-51, B2-64 and B2-77 do not contain Bi and Pb, and formula (4) is not true, and therefore, wettability is poor.

< combination of soldering flux and solder alloy >)

When the solder alloys of examples B (examples B2 to B95; and examples B2-1 to B2-108) were each combined using the respective fluxes of examples A2 to A45 instead of the flux of example A1, good results were obtained in terms of thickening inhibition effect, deltaT, and wettability.

< preparation of flux composition for flow soldering >

Flux compositions for flow soldering of reference examples C1 to C36 were prepared with compositions shown in tables 13 to 15 below.

TABLE 19

TABLE 20

TABLE 21

When the flux according to the present embodiment is used for forming a flux for flow soldering, residual cracking of flux residues is suppressed, and solder wettability is also excellent.

The present application is based on japanese patent application No. 2019, 5-month 27 (japanese patent application No. 2019-098775), japanese patent application No. 2019, 5-month 27 (japanese patent application No. 2019-098782), japanese patent application No. 2020, 5-month 26 (japanese patent application No. 2020-091559), and japanese patent application No. 2019, 5-month 26 (japanese patent application No. 2020-091571), the contents of which are incorporated herein by reference.

Claims

1. A composition for a soldering flux comprising: 1 or more selected from the group consisting of a maleic acid-modified rosin ester, a maleic acid-modified rosin amide, a hydride of the maleic acid-modified rosin ester, and a hydride of the maleic acid-modified rosin amide, wherein the maleic acid-modified rosin ester does not include a maleic acid-modified rosin ester multimer,

wherein the maleic acid-modified rosin ester or the maleic acid-modified rosin amide is 1 or more selected from the group consisting of compounds represented by the following formulas (1) to (7),

/>

wherein R 'each independently represents an optionally substituted, linear or branched alkyl group, an alkylene glycol group, or a terminal modified polyalkylene oxide group, and R' each independently represents an optionally substituted, linear or branched alkylene group, or a 2-valent alkylene glycol group.

2. A flux for soldering a solder alloy, comprising the composition for flux of claim 1.

3. A soldering flux according to claim 2, wherein the content of the maleic acid-modified rosin ester and/or the maleic acid-modified rosin amide exceeds 0% by weight and is 60% by weight or less relative to the whole of the soldering flux.

4. A soldering flux according to claim 2 or claim 3 wherein the flux further comprises a thixotropic agent.

5. A flux according to claim 4, wherein,

the soldering flux further comprises:

0 to 20% by weight of an amine,

An organic halogen compound in an amount of 0 to 5 wt%

0 to 2 wt% of an amine hydrohalate, or

0 to 5% by weight of an antioxidant,

0 to 80% by weight of a resin.

6. A solder paste, comprising: the flux according to any one of claims 2 to 5, and a solder alloy.

7. A solder paste according to claim 6,

wherein the solder alloy has the following alloy composition:

275≤2As+Bi+Pb (1)

0<2.3×10 ^-4 ×Bi+8.2×10 ^-4 ×Pb≤7 (2)

In the formulas (1) and (2), as, bi, and Pb represent the contents in mass ppm in the alloy composition, respectively.

8. A solder paste according to claim 6,

wherein the solder alloy has the following alloy composition:

as:25 to 300 mass ppm; pb: more than 0 mass ppm and less than 5100 mass ppm; and

sb: more than 0 mass ppm and 3000 mass ppm or less and Bi: at least 1 of more than 0 mass ppm and 10000 mass ppm or less; the balance is composed of Sn, and satisfies the following formulas (3) and (4):

275≤2As+Sb+Bi+Pb (3)

0.01≤(2As+Sb)/(Bi+Pb)≤10.00(4)

in the formulas (3) and (4), as, sb, bi, and Pb represent the contents in mass ppm in the alloy composition, respectively.