Preparation method of soldering flux and joint body

Abstract

The present invention uses a soldering flux containing rosin, terpene phenol resin and an activator. The terpene phenol resin has a hydroxyl value exceeding 70 mgKOH / g. The activator contains an organic acid having a solubility parameter (SP value) of 11.00 or more or an organic acid represented by the general formula (1). In the formula (1), R 1 represents a chain hydrocarbon group having 2 to 15 carbon atoms, an alicyclic hydrocarbon group having 3 to 15 carbon atoms, an aromatic group or a carboxyl group, wherein the chain hydrocarbon group and the alicyclic hydrocarbon group each have a hydroxyl group or a carboxyl group.

Description

Technical Field

[0001] The present invention relates to a method for preparing a soldering flux and a joint body. This application claims priority based on Japanese Patent Application No. 2021-182145 filed in Japan on November 8, 2021, and the contents thereof are incorporated herein by reference. Background Art

[0002] Usually, fixing components to a substrate and electrically connecting components to the substrate are performed by soldering. In soldering, flux, solder, and solder paste mixed with flux and solder are used.

[0003] The flux has the ability to chemically remove the metal surface of the object to be soldered and the metal oxides present in the solder, and to allow the metal elements to move at the boundary between the two. Therefore, by soldering with the flux, an intermetallic compound is formed between the two, thereby obtaining a strong joint.

[0004] In soldering, a method such as reflow soldering or flow soldering is used depending on the size of the object to be joined.

[0005] In reflow soldering, solder paste is first printed on a substrate, then components are mounted, and the substrate with components mounted is heated in a heating furnace called a reflow oven to perform soldering.

[0006] In flow soldering, first, flux is applied to a substrate on which components are mounted, and then soldering is performed by bringing molten solder jetting from below into contact with the soldering surface while the substrate on which components are mounted is conveyed.

[0007] The flux used in soldering generally contains a resin component, a solvent, an activator, etc. For example, the embodiment of Patent Document 1 describes a flux for flow soldering, which contains rosin as a resin component and an organic acid, an organic halogen compound or an amine hydrohalide as an activator.

[0008] Prior art documents

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent No. 6617848 Summary of the invention

[0011] Problems to be solved by the present invention

[0012] The resin component and activator contained in the flux remain as flux residue at the joint between the component and the substrate after soldering. Depending on the activator contained in the flux, it is sometimes easy to precipitate in the flux residue after soldering. The activator precipitated in the flux residue absorbs moisture in the air and ionizes. The ionized activator corrodes the metal and causes migration.

[0013] Therefore, an object of the present invention is to provide a flux and a method for producing a joint body that can further suppress the precipitation of an activating agent in the flux residue after soldering.

[0014] Means of solving the problem

[0015] The present invention includes the following aspects.

[0016] A first aspect of the present invention is a soldering flux comprising rosin, a terpene-phenol resin and an activator, wherein the terpene-phenol resin has a hydroxyl value exceeding 70 mgKOH / g and the activator contains an organic acid (A1) having a solubility parameter (SP value) of 11.00 or more.

[0017] In the soldering flux of the first aspect, the content of the organic acid (A1) is preferably 0.05% by mass or more and 6% by mass or less relative to the total mass (100% by mass) of the soldering flux.

[0018] In the soldering flux of the first aspect, the ratio (mass ratio) of the content of the organic acid (A1) relative to the content (100 parts by mass) of the terpene-phenol resin is preferably 1 part by mass or more and 600 parts by mass or less.

[0019] A second aspect of the present invention is a soldering flux comprising rosin, a terpene-phenol resin and an activator, wherein the terpene-phenol resin has a hydroxyl value exceeding 70 mgKOH / g, and the activator comprises an organic acid (A2) represented by the following general formula (1).

[0020] R 1 -COOH···(1)

[0021] [Where R 1 represents a chain hydrocarbon group having 2 to 15 carbon atoms, an alicyclic hydrocarbon group having 3 to 15 carbon atoms, an aromatic group or a carboxyl group. The chain hydrocarbon group and the alicyclic hydrocarbon group each have a hydroxyl group or a carboxyl group.]

[0022] In the soldering flux of the second aspect, the content of the organic acid (A2) is preferably 0.05% by mass or more and 6% by mass or less relative to the total mass (100% by mass) of the soldering flux.

[0023] In the soldering flux of the second aspect, the ratio (mass ratio) of the content of the organic acid (A2) relative to the content (100 parts by mass) of the terpene-phenol resin is preferably 1 part by mass or more and 600 parts by mass or less.

[0024] In the soldering flux of the first aspect or the second aspect, the content of the terpene phenol resin is preferably 0.1% by mass or more and 20% by mass or less relative to the total mass (100% by mass) of the soldering flux.

[0025] A third aspect of the present invention is a method for producing a bonded body, comprising the step of obtaining a bonded body by soldering a solder alloy on a surface of a substrate treated with the flux of the first aspect or the second aspect.

[0026] Effects of the Invention

[0027] According to the present invention, it is possible to provide a flux and a method for producing a joint body that can further suppress the precipitation of an activating agent in the flux residue after soldering. DETAILED DESCRIPTION

[0028] (Flux)

[0029] The flux of the first aspect and the second aspect can be used for either flow soldering or reflow soldering, but is preferably used for flow soldering.

[0030] The substrate used for flow soldering is made of a cheap and difficult-to-wet material and has the characteristic of being easily oxidized. In addition, the soldering time of flow soldering is short. For these reasons, a highly active activator is used in flow soldering. The highly active activator is difficult to dissolve in the flux residue containing resin etc. after soldering and precipitates in the flux residue. As a highly active activator, a specific organic acid described later is used.

[0031] In the soldering flux of the first aspect and the second aspect, a terpene phenol resin having a hydroxyl value exceeding 70 mgKOH / g relative to the specific organic acid is used. This can suppress precipitation of the activator in the soldering flux residue.

[0032] Hereinafter, the soldering flux of the first aspect and the second aspect will be described in detail.

[0033] In this specification, the solid content of the flux refers to all components remaining after removing only the solvent from the flux.

[0034] In the present specification, the hydroxyl value of the terpene phenol resin refers to the hydroxyl value measured by the potentiometric titration method according to 7.2 of JIS K0070 "Testing methods for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponifiable matter of chemical products".

[0035] The hydroxyl value measured by this method is a weighted average value of the hydroxyl values ​​of all types of terpene phenol resins contained in the flux.

[0036] [First method]

[0037] One embodiment of the soldering flux of the first aspect is as follows: The soldering flux of this embodiment contains rosin, terpene phenol resin, an activator, a solvent (S), and other components as needed.

[0038] The terpene phenol resin has a hydroxyl value exceeding 70 mgKOH / g. The activator contains an organic acid (A1) having a solubility parameter (SP value) of 11.00 or more. The soldering flux of this embodiment is suitable as a soldering flux for flow soldering.

[0039] <Rosin>

[0040] In the present invention, the term "rosin" includes natural resins containing abietic acid as a main component, mixtures of abietic acid and isomers thereof, and substances obtained by chemically modifying natural resins (sometimes referred to as rosin derivatives).

[0041] The total content of abietic acid and isomers of abietic acid in the natural resin is, for example, 40% by mass or more and 80% by mass or less relative to the natural resin.

[0042] In the present specification, the term "main component" refers to a component whose content in the compound is 40% by mass or more among the components constituting the compound.

[0043] Representative examples of isomers of abietic acid include neoabietic acid, palustric acid, and levopimaric acid. The structure of abietic acid is shown below.

[0044] [Chemical formula 1]

[0045]

[0046] Examples of the “natural resin” include gum rosin, wood rosin, and tall oil rosin.

[0047] In the present invention, "substances obtained by chemically modifying natural resins (rosin derivatives)" include substances obtained by subjecting the "natural resins" to one or more treatments selected from hydrogenation, dehydrogenation, neutralization, alkylene oxide addition, amidation, dimerization and polymerization, esterification, and Diels-Alder cycloaddition.

[0048] Examples of the rosin derivative include purified rosin and modified rosin.

[0049] Examples of the modified rosin include hydrogenated rosin, polymerized rosin, polymerized hydrogenated rosin, disproportionated rosin, acid-modified rosin, rosin ester, acid-modified hydrogenated rosin, acid-modified disproportionated rosin, acid-anhydride-modified disproportionated rosin, phenol-modified rosin, and α,β-unsaturated carboxylic acid-modified products (acrylated rosin, maleated rosin, fumarated rosin, etc.), purified products, hydrogenated products, and disproportionated products of the polymerized rosin, purified products, hydrogenated products, and disproportionated products of the α,β-unsaturated carboxylic acid-modified products, abietol, abietamine, hydrogenated abietol, rosin ester, hydrogenated rosin ester, rosin soap, hydrogenated rosin soap, and acid-modified rosin soap.

[0050] Examples of rosin amines include dehydroabietylamine and dihydroabietylamine. Abietylamine refers to so-called disproportionated rosin amines. The structures of dehydroabietylamine and dihydroabietylamine are shown below.

[0051] [Chemical formula 2]

[0052]

[0053] The rosin may be used alone or in combination of two or more.

[0054] As the rosin, a rosin derivative is preferably used.

[0055] As the rosin derivative, it is preferable to use one or more selected from the group consisting of acid-modified hydrogenated rosin, acid-modified rosin, hydrogenated rosin, polymerized rosin and rosin ester.

[0056] As the acid-modified hydrogenated rosin, acrylic acid-modified hydrogenated rosin is preferably used.

[0057] As the acid-modified rosin, acrylic acid-modified rosin is preferably used.

[0058] The content of the rosin in the flux is preferably 1% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 25% by mass or less, and further preferably 2% by mass or more and 20% by mass or less, relative to the total amount of the flux (100% by mass).

[0059] In the solid content of the flux, the content of the rosin is preferably 10% by mass or more and 90% by mass or less, more preferably 20% by mass or more and 80% by mass or less, and further preferably 30% by mass or more and 75% by mass or less, relative to the total amount (100% by mass) of the solid content.

[0060] <Terpene phenol resin>

[0061] In the present specification, the terpene-phenol resin refers to a copolymer of a terpene monomer and phenols, a hydrogenated product of the copolymer, and a copolymer of a terpene monomer, a monomer other than the terpene monomer, and phenols, and a hydrogenated product of the copolymer.

[0062] Examples of the terpene phenol resin include terpene resins, modified terpene resins, terpene phenol resins, and modified terpene phenol resins.

[0063] Examples of the modified terpene resin include hydrogenated terpene resin, aromatic modified terpene resin, hydrogenated aromatic modified terpene resin, and the like.

[0064] Examples of the modified terpene-phenol resin include hydrogenated terpene-phenol resins and the like.

[0065] Terpene monomers include, for example, hemiterpenes having 5 carbon atoms such as isoprene, monoterpenes having 10 carbon atoms, sesquiterpenes having 15 carbon atoms, diterpenes having 20 carbon atoms, diperpenes having 25 carbon atoms, triterpenes having 30 carbon atoms, and tetraterpenes having 40 carbon atoms.

[0066] Examples of the phenols include phenol, cresol, and xylenol.

[0067] The hydroxyl value of the terpene phenol resin exceeds 70 mgKOH / g, may be 90 mgKOH / g or more, preferably 110 mgKOH / g or more, more preferably 130 mgKOH / g or more, further preferably 140 mgKOH / g or more, particularly preferably 170 mgKOH / g or more, and most preferably 190 mgKOH / g or more.

[0068] The upper limit of the hydroxyl value of the terpene phenol resin is not particularly limited as long as the effects of the present invention can be exhibited, and may be, for example, 300 mgKOH / g or less, 250 mgKOH / g or less, or 230 mgKOH / g or less.

[0069] For example, the hydroxyl value of the terpene-phenol resin may be greater than 70 mgKOH / g and less than 300 mgKOH / g, may be greater than 90 mgKOH / g and less than 300 mgKOH / g, preferably greater than 110 mgKOH / g and less than 300 mgKOH / g, more preferably greater than 130 mgKOH / g and less than 300 mgKOH / g, further preferably greater than 140 mgKOH / g and less than 300 mgKOH / g, particularly preferably greater than 170 mgKOH / g and less than 300 mgKOH / g, and may be greater than 190 mgKOH / g and less than 300 mgKOH / g.

[0070] Alternatively, the hydroxyl value of the terpene-phenol resin may be greater than 70 mgKOH / g and less than 250 mgKOH / g, may be greater than 90 mgKOH / g and less than 250 mgKOH / g, preferably greater than 110 mgKOH / g and less than 250 mgKOH / g, more preferably greater than 130 mgKOH / g and less than 250 mgKOH / g, further preferably greater than 140 mgKOH / g and less than 250 mgKOH / g, particularly preferably greater than 170 mgKOH / g and less than 250 mgKOH / g, and may be greater than 190 mgKOH / g and less than 250 mgKOH / g.

[0071] When the hydroxyl value of the terpene phenol resin exceeds the above lower limit, the effect of suppressing the precipitation of the highly polar organic acid (A1) in the flux residue is further enhanced.

[0072] When the hydroxyl value of the terpene phenol resin is equal to or less than the above upper limit, moisture absorption can be further reduced, thereby further suppressing a decrease in the insulation resistance value of the soldering flux and further suppressing the occurrence of migration.

[0073] Examples of the terpene phenol resin include easily available resins such as YS Polyster (terpene phenol resin: manufactured by Yasuhara Chemical Co., Ltd.), TAMANOL (terpene phenol resin: manufactured by Arakawa Chemical Industries, Ltd.), TELLTAG 80 (terpene phenol resin: manufactured by Nippon Terpene Chemical Co., Ltd.), and Sylvares TP (terpene phenol resin: manufactured by Air Brown Co., Ltd.) A terpene phenol resin can be selected from these resins so as to obtain a desired hydroxyl value.

[0074] The terpene phenol resins may be used alone or in combination of two or more.

[0075] The soldering flux of this embodiment may contain one type of terpene phenol resin having a hydroxyl value exceeding 70 mgKOH / g. Alternatively, the soldering flux of this embodiment may contain two or more terpene phenol resins having different hydroxyl values, and the hydroxyl value obtained by weighted average of these hydroxyl values ​​exceeds 70 mgKOH / g.

[0076] The content of the terpene phenol resin in the soldering flux is preferably 0.1% to 20% by mass, more preferably 0.2% to 10% by mass, and further preferably 0.5% to 5% by mass, relative to the total amount of the soldering flux (100% by mass).

[0077] In the solid content of the flux, the content of the terpene phenol resin is preferably 3 mass % or more and 50 mass % or less, more preferably 4 mass % or more and 40 mass % or less, and further preferably 5 mass % or more and 30 mass % or less, relative to the total amount of the solid content (100 mass %).

[0078] When the content of the terpene phenol resin is equal to or greater than the above lower limit, precipitation of the organic acid (A1) in the flux residue after soldering can be further suppressed.

[0079] When the content of the terpene phenol resin is equal to or less than the above upper limit, the possibility that the viscosity of the flux becomes too high can be reduced.

[0080] The mixing ratio of rosin and terpene-phenol resin, in terms of the mass ratio of rosin / terpene-phenol resin, i.e., the ratio of the content of rosin to the content of terpene-phenol resin, is preferably 0.5 to 20, more preferably 1 to 10, and even more preferably 1.5 to 8.

[0081] <Activator>

[0082] 《Special active agent》

[0083] The soldering flux of the present embodiment contains an organic acid (A1) having a solubility parameter (SP value) of 11 or more as a specific activator.

[0084] [Dissolution parameter (SP value)]

[0085] In this specification, the solubility parameter (SP value) refers to a value calculated from the molecular structure based on the Fedors method. The SP value (δ) can be obtained from the following formula (SP).

[0086] δ=(ΔE / ΔV) 1 / 2 (cal / cm 3 ) 1 / 2 ···(sp)

[0087] In the formula (sp), ΔE represents the total of the vaporization energies (cal / mol) of atoms and atomic groups in the molecule of the organic acid (A1).

[0088] ΔV represents the molar volume (cm2) of the atoms and atomic groups in the molecule of the organic acid (A1) at 25°C. 3 / mol).

[0089] As the evaporation energy and the molar volume, the values ​​described in Robert F. Fedors, A method for estimating both the solubility parameters and molar volumes of liquids. Polymer Engineering and Science, 14, 147-154 (1974) can be used.

[0090] The SP value of the organic acid (A1) is 11.00 or more, preferably 11.50 or more, more preferably 11.70 or more, further preferably 12.00 or more, particularly preferably 12.50 or more, and most preferably 13.00 or more.

[0091] The upper limit of the SP value of the organic acid (A1) is not particularly limited, and may be, for example, 25 or 23 or less.

[0092] For example, the SP value of the organic acid (A1) may be greater than or equal to 11.00 and less than or equal to 25.00, may be greater than or equal to 11.50 and less than or equal to 25.00, may be greater than or equal to 11.70 and less than or equal to 25.00, may be greater than or equal to 12.00 and less than or equal to 25.00, may be greater than or equal to 12.50 and less than or equal to 25.00, or may be greater than or equal to 13.00 and less than or equal to 25.00.

[0093] Alternatively, the SP value of the organic acid (A1) may be greater than or equal to 11.00 and less than or equal to 23.00, may be greater than or equal to 11.50 and less than or equal to 23.00, may be greater than or equal to 11.70 and less than or equal to 23.00, may be greater than or equal to 12.00 and less than or equal to 23.00, may be greater than or equal to 12.50 and less than or equal to 23.00, or may be greater than or equal to 13.00 and less than or equal to 23.00.

[0094] The organic acid (A1) having an SP value of not less than the above lower limit has high polarity and is therefore likely to precipitate in flux residue containing resin and the like after soldering.

[0095] The soldering flux of the present embodiment uses a terpene phenol resin having a hydroxyl value exceeding 70 mgKOH / g. This suppresses the precipitation of the organic acid (A1) having an SP value not less than the above lower limit in the soldering flux residue.

[0096] The organic acid (A1) may be a dicarboxylic acid.

[0097] Examples of the dicarboxylic acid include oxalic acid (15.22), malonic acid (14.03), succinic acid (13.21), glutaric acid (12.61), adipic acid (12.15), pimelic acid, suberic acid (11.49), azelaic acid (11.25), sebacic acid (11.04), 2,4-diethylglutaric acid (14.89), and 1,3-cyclohexanedicarboxylic acid (12.80).

[0098] The numerical values ​​in parentheses represent the SP value of each dicarboxylic acid.

[0099] Alternatively, the organic acid (A1) may be a hydroxycarboxylic acid.

[0100] Examples of the hydroxycarboxylic acid include 2,2-bis(hydroxymethyl)propionic acid (16.12) and 2,2-bis(hydroxymethyl)butanoic acid (18.31).

[0101] The numerical values ​​in parentheses represent the SP value of each hydroxycarboxylic acid.

[0102] Alternatively, the organic acid (A1) may be an aromatic carboxylic acid.

[0103] Examples of the aromatic carboxylic acid include picolinic acid (12.78) and dipicolinic acid (13.37).

[0104] The organic acid (A1) is preferably succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid or 2,2-bis(hydroxymethyl)propionic acid, more preferably succinic acid, glutaric acid, adipic acid or 2,2-bis(hydroxymethyl)propionic acid, further preferably succinic acid or 2,2-bis(hydroxymethyl)propionic acid.

[0105] The organic acid (A1) may be used alone or in combination of two or more.

[0106] The content of the organic acid (A1) in the soldering flux is preferably 0.05% by mass to 6% by mass, more preferably 0.1% by mass to 4% by mass, and further preferably 0.1% by mass to 3% by mass, relative to the total mass of the soldering flux (100% by mass).

[0107] In the solid content of the flux, the content of the organic acid (A1) is preferably 0.5 mass % to 50 mass % inclusive, more preferably 0.5 mass % to 40 mass % inclusive, and further preferably 1 mass % to 40 mass % inclusive, relative to the total amount (100 mass %) of the solid content.

[0108] When the content of the organic acid (A1) is equal to or more than the lower limit, the wettability of the flux can be further improved.

[0109] When the content of the organic acid (A1) is equal to or less than the upper limit, precipitation of the organic acid (A1) in the flux residue after soldering can be further suppressed.

[0110] The mixing ratio of the organic acid (A1) and the terpene-phenol resin, measured as the mass ratio represented by organic acid (A1) / terpene-phenol resin, that is, the ratio of the organic acid (A1) to the content (100 parts by mass) of the terpene-phenol resin, can be 1 part by mass or more and 600 parts by mass or less, preferably 2 parts by mass or more and 600 parts by mass or less, more preferably 1 part by mass or more and 400 parts by mass or less, further preferably 1 part by mass or more and 200 parts by mass or less, particularly preferably 1 part by mass or more and 100 parts by mass or less, and most preferably 1 part by mass or more and 50 parts by mass or less.

[0111] When the content ratio of the organic acid (A1) is equal to or greater than the above lower limit, weldability can be improved.

[0112] When the content ratio of the organic acid (A1) is equal to or less than the upper limit, the precipitation of the organic acid (A1) in the flux residue after soldering can be further suppressed.

[0113] Other active agents

[0114] The activator contained in the soldering flux of the present embodiment may contain other activators in addition to the organic acid (A1).

[0115] Examples of the other activators include organic acid-based activators other than the organic acid (A1), amine-based activators, and halogen-based activators.

[0116] [Other organic acid based surfactants]

[0117] Examples of the organic acid-based activator include undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, nonadecanedioic acid, eicosanedioic acid, 4-tert-butylbenzoic acid, palmitic acid, 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester, dimer acid, trimer acid, hydrogenated dimer acid which is a hydrogenated product of dimer acid, and hydrogenated trimer acid which is a hydrogenated product of trimer acid.

[0118] Examples of the dimer acid and trimer acid include a dimer acid as a reaction product of oleic acid and linoleic acid, a trimer acid as a reaction product of oleic acid and linoleic acid, a dimer acid as a reaction product of acrylic acid, a trimer acid as a reaction product of acrylic acid, a dimer acid as a reaction product of methacrylic acid, a trimer acid as a reaction product of methacrylic acid, a dimer acid as a reaction product of acrylic acid and methacrylic acid, a trimer acid as a reaction product of acrylic acid and methacrylic acid, a dimer acid as a reaction product of oleic acid, a trimer acid as a reaction product of oleic acid, a dimer acid as a reaction product of linoleic acid, a trimer acid as a reaction product of linolenic acid, a dimer acid as a reaction product of linolenic acid, a trimer acid as a reaction product of linolenic acid, a dimer acid as a reaction product of acrylic acid and oleic acid, a trimer acid as a reaction product of acrylic acid and linoleic acid, and a dimer acid as a reaction product of acrylic acid and oleic acid. Acid, trimer acid which is a reaction product of acrylic acid and linoleic acid, dimer acid which is a reaction product of acrylic acid and linolenic acid, trimer 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, trimer acid which is a reaction product of methacrylic acid and oleic acid, dimer acid which is a reaction product of methacrylic acid and linoleic acid, trimer 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, trimer acid which is a reaction product of methacrylic acid and linolenic acid, dimer acid which is a reaction product of oleic acid and linolenic acid, trimer acid which is a reaction product of linoleic acid and linolenic acid, dimer acid which is a reaction product of linoleic acid and linolenic acid, trimer acid which is a reaction product of linoleic acid and linolenic acid, hydrogenated dimer acid which is a hydrogenated product of the above dimer acids, hydrogenated trimer acid which is a hydrogenated product of the above trimer acids, and the like.

[0119] For example, the dimer acid, which is a reaction product of oleic acid and linoleic acid, is a dimer having 36 carbon atoms. Also, the trimer acid, which is a reaction product of oleic acid and linoleic acid, is a trimer having 54 carbon atoms.

[0120] The other organic acid-based activators may be used alone or in combination of two or more.

[0121] [Amine surfactant]

[0122] Examples of the amine-based activator include rosin amine, azoles, guanidines, alkylamine compounds, and amino alcohol compounds.

[0123] Examples of the rosin amine include the rosin amines described above in <rosin>.

[0124] Examples of the azoles include 2-methylimidazole, 2-ethylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-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-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazole trimellitate, 2,4-diamino-6-[2″-methylimidazolyl-(1′)]-ethyl tris-imidazolyl 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-benzylimidazole chloride, 2-methylimidazoline, 2-phenylimidazoline, 2,4-diamino-6-vinyl-s-triazine, 2 ,4-diamino-4,6-vinyl-s-triazine isocyanuric acid adduct, 2,4-diamino-6-methacryloyloxyethyl-s-triazine, epoxy-imidazole adduct, 2-methylbenzimidazole, 2-octylbenzimidazole, 2-pentylbenzimidazole, 2-(1-ethylpentyl)benzimidazole, 2-nonylbenzimidazole, 2-(4-thiazolyl)benzimidazole, benzimidazole, 1,2,4-triazole, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-pentylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 2 ,2'-methylenebis[6-(2H-benzotriazol-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-benzotriazol-1-yl)methyl]imino]bisethanol, 1-(1',2'-dicarboxyethyl)benzotriazole, 1-(2,3-dicarboxypropyl)benzotriazole, 1-[(2-ethylhexylamino)methyl]benzotriazole, 2,6-Bis[(1H-benzotriazol-1-yl]methyl]-4-methylphenol, 5-methylbenzotriazole, 5-phenyltetrazolyl, etc.

[0125] Examples of the guanidines include 1,3-diphenylguanidine, 1,3-di-o-tolylguanidine, 1-o-tolylguanidine, 1,3-di-o-isopropylphenylguanidine, and 1,3-di-o-isopropylphenyl-2-propionylguanidine.

[0126] Examples of the alkylamine compound include ethylamine, triethylamine, ethylenediamine, triethylenetetramine, cyclohexylamine, hexadecylamine, and stearylamine.

[0127] Examples of the amino alcohol compound include N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine and monoisopropanolamine.

[0128] The amine-based activators may be used alone or in combination of two or more.

[0129] [Halogen-based activators]

[0130] Examples of the halogen-based activator include amine hydrohalide salts and organic halogen compounds other than amine hydrohalide salts.

[0131] Amine hydrohalides are compounds formed by reacting amines with hydrogen halides.

[0132] Examples of the amines include those listed in the section "Amine-based activators". Examples of the hydrogen halides include hydrides of chlorine, bromine, and iodine.

[0133] More specifically, examples of the amine hydrohalide salt include cyclohexylamine hydrobromide, hexadecylamine hydrobromide, stearylamine hydrobromide, ethylamine hydrobromide, 1,3-diphenylguanidine hydrobromide, ethylamine hydrochloride, stearylamine hydrochloride, diethylaniline hydrobromide, diethanolamine hydrochloride, 2-ethylhexylamine hydrobromide, pyridine hydrobromide, isopropylamine hydrobromide, diethylamine hydrobromide, dimethylamine hydrobromide, dimethylamine hydrobromide, rosinamine hydrobromide, 2-ethylhexylamine hydrochloride, isopropylamine hydrobromide, cyclohexylamine hydrobromide, 2-piperidine hydrobromide, 1,3-diphenylguanidine hydrochloride, dimethylbenzylamine hydrochloride, hydrazine hydrate hydrobromide, dimethylcyclohexylamine hydrochloride, trinonylamine hydrobromide, diethylaniline hydrobromide, 2-diethylaminoethanol hydrobromide, 2-diethylaminoethanol hydrochloride, ammonium chloride, di Allylamine hydrochloride, diallylamine hydrobromide, diethylamine hydrochloride, triethylamine hydrobromide, triethylamine hydrochloride, hydrazine hydrochloride, hydrazine dihydrochloride, hydrazine hydrobromide, hydrazine dihydrobromide, pyridine hydrochloride, aniline hydrobromide, butylamine hydrochloride, hexylamine hydrochloride, n-octylamine hydrochloride, dodecylamine hydrochloride, dimethylcyclohexylamine hydrobromide, ethylenediamine dihydrobromide, rosinamine hydrobromide, 2-phenylimidazole hydrobromide, 4-benzylpyridine hydrobromide, L-glutamic acid hydrochloride, N-methylmorpholine hydrochloride, betaine hydrochloride, 2-piperidine hydroiodide, cyclohexylamine hydroiodide, 1,3-diphenylguanidine hydrofluoride, diethylamine hydrofluoride, 2-ethylhexylamine hydrofluoride, cyclohexylamine hydrofluoride, ethylamine hydrofluoride, rosinamine hydrofluoride, cyclohexylamine tetrafluoroborate and dicyclohexylamine tetrafluoroborate, etc.

[0134] In addition, as a halogen-based activator, for example, a salt formed by reacting an amine with tetrafluoroboric acid (HBF4) or a complex formed by reacting an amine with boron trifluoride (BF3) can also be used. Examples of the complex include boron trifluoride piperidine and the like.

[0135] Examples of the organic halogen compound other than the amine hydrohalide salt include halogenated aliphatic compounds. The halogenated aliphatic hydrocarbon group refers to a group in which a part or all of the hydrogen atoms constituting the aliphatic hydrocarbon group are substituted with halogen atoms.

[0136] Examples of the halogenated aliphatic compound include halogenated aliphatic alcohols and halogenated heterocyclic compounds.

[0137] Examples of the halogenated aliphatic alcohol include 1-bromo-2-propanol, 3-bromo-1-propanol, 3-bromo-1,2-propanediol, 1-bromo-2-butanol, 1,3-dibromo-2-propanol, 2,3-dibromo-1-propanol, 1,4-dibromo-2-butanol, and trans-2,3-dibromo-2-butene-1,4-diol.

[0138] Examples of the halogenated heterocyclic compound include compounds represented by the following general formula (2).

[0139] R 11 -(R 12 )n(2)

[0140] [Where R 11 represents an n-valent heterocyclic group. 12 represents a halogenated aliphatic hydrocarbon group.]

[0141] As R 11 The heterocyclic ring of the n-valent heterocyclic group in the formula (I) may be a ring structure in which a portion of the carbon atoms constituting the aliphatic hydrocarbon or aromatic hydrocarbon ring is substituted with a heteroatom. Examples of the heteroatom in the heterocyclic ring include an oxygen atom, a sulfur atom, a nitrogen atom, and the like. The heterocyclic ring is preferably a 3- to 10-membered ring, and more preferably a 5- to 7-membered ring. Examples of the heterocyclic ring include an isocyanurate ring and the like.

[0142] R 12 The halogenated aliphatic hydrocarbon group in preferably has 1 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, and still more preferably 3 to 5 carbon atoms. 12 Preferred are brominated aliphatic hydrocarbon groups and chlorinated aliphatic hydrocarbon groups, more preferred are brominated aliphatic hydrocarbon groups, and still more preferred are brominated saturated aliphatic hydrocarbon groups.

[0143] Examples of the halogenated heterocyclic compound include tris-(2,3-dibromopropyl)isocyanurate and the like.

[0144] In addition, as organic halogen compounds other than amine hydrohalides, for example, iodinated carboxyl compounds such as 2-iodobenzoic acid, 3-iodobenzoic acid, 2-iodopropionic acid, 5-iodosalicylic acid, and 5-iodoanthranilic acid; chlorinated carboxyl compounds such as 2-chlorobenzoic acid and 3-chloropropionic acid; halogenated carboxyl compounds such as brominated carboxyl compounds such as 2,3-dibromopropionic acid, 2,3-dibromosuccinic acid, and 2-bromobenzoic acid, hydrobromic acid, carbon tetrabromide, fatty acid methyl ester chloride (chlorinated paraffin), tetrabromoethane, etc.

[0145] The halogen-based activators may be used alone or in combination of two or more.

[0146] <Solvent (S)>

[0147] Examples of the solvent (S) include water, alcohol solvents, glycol ether solvents, and terpineols.

[0148] Examples of the alcohol solvent include ethanol, 1-propanol, 2-propanol, 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-hexyne-2,5-diol, 2,3-dimethyl-2,3-butanediol, 2-methylpentane-2,4-diol, 1,1,1 -tri(hydroxymethyl)propane, 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, 1-ethynyl-1-cyclohexanol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, etc.

[0149] Examples of the glycol ether solvent include diethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether, diethylene glycol monohexyl ether (hexyl diglycol), diethylene glycol dibutyl ether, triethylene glycol monobutyl ether, methpropylene triethylene glycol, butylpropylene triethylene glycol, triethylene glycol butyl methyl ether, and tetraethylene glycol dimethyl ether.

[0150] The solvent (S) may be used alone or in combination of two or more.

[0151] From the viewpoint of improving volatility during preheating, the solvent (S) preferably contains a solvent (S1) having a boiling point of 100° C. or less. The boiling point of the solvent (S1) is preferably 60° C. or more and 100° C. or less, more preferably 70° C. or more and 100° C. or less, further preferably 75° C. or more and 100° C. or less, and particularly preferably 80° C. or more and 100° C. or less.

[0152] The content of the solvent (S1) is preferably 70% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, further preferably 90% by mass or more and 100% by mass or less, particularly preferably 95% by mass or more and 100% by mass or less, and may be 100% by mass, relative to the total mass (100% by mass) of the solvent (S). By making the content of the solvent (S1) above the lower limit, the volatility of the solvent (S) under preheating can be easily increased.

[0153] From the viewpoint of solubility of the specific active agent, the solvent (S1) having a boiling point of 100° C. or less is preferably an alcohol solvent.

[0154] The alcohol solvent preferably contains 2-propanol.

[0155] The content of the solvent (S) in the flux is preferably 40% by mass or more and 98% by mass or less, more preferably 60% by mass or more and 98% by mass or less, and further preferably 70% by mass or more and 98% by mass or less, relative to the total amount of the flux (100% by mass).

[0156] <Other ingredients>

[0157] The soldering flux of the present embodiment may contain other components in addition to the rosin, terpene phenol resin, activator, and solvent as necessary.

[0158] Examples of other components include a thixotropic agent, a resin component other than rosin and terpene phenol resin, a metal deactivator, a surfactant, a silane coupling agent, an antioxidant, and a colorant.

[0159] 《Resin components other than rosin and terpene-phenol resins》

[0160] Examples of the resin component other than the rosin-based resin include styrene resin, modified styrene resin, xylene resin, modified xylene resin, acrylic resin, polyethylene resin, acrylic-polyethylene copolymer resin, epoxy resin, and silicone resin.

[0161] Examples of the modified styrene resin include styrene acrylic resin, styrene maleic resin, etc. Examples of the modified xylene resin include phenol-modified xylene resin, alkylphenol-modified xylene resin, phenol-modified resol-type xylene resin, polyol-modified xylene resin, and polyoxyethylene-added xylene resin.

[0162] 《Metal passivator》

[0163] Examples of the metal deactivator include hindered phenol compounds, nitrogen compounds, etc. The "metal deactivator" referred to herein refers to a compound having a function of preventing metal from being degraded due to contact with a certain compound.

[0164] The hindered phenol compound refers to a phenol compound having a bulky substituent (for example, a branched or cyclic alkyl group such as a tert-butyl group) at at least one ortho position of phenol.

[0165] The hindered phenol compound is not particularly limited, and examples thereof include bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionic acid][ethylenebis(oxyethylene)], N,N'-hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], 1,6-hexanediolbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,2'-methylenebis[6-(1-methylcyclohexyl)-p-cresol], 2,2'-methylenebis(6-tert-butyl-p-cresol), 2,2'-methylenebis(6-tert-butyl-4-ethylphenol), triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediolbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,4-bis(n-octyl)-1,4-diol 2-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N'-hexamethylenebis( 3,5-di-tert-butyl-4-hydroxy-hydrocinnamic acid amide), 3,5-di-tert-butyl-4-hydroxybenzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, N,N'-bis[2-[2-(3,5-di-tert-butyl-4-hydroxyphenyl)ethylcarbonyloxy]ethyl]oxalamide, compounds represented by the following chemical formulas, etc.

[0166] [Chemical formula 3]

[0167]

[0168] (wherein, Z is an alkylene group which may be substituted. 101 and R 102 Each is independently an alkyl group, an aralkyl group, an aryl group, a heteroaryl group, a cycloalkyl group or a heterocycloalkyl group which may be substituted. 103 and R 104 Each is independently an alkyl group which may be substituted.)

[0169] Examples of the nitrogen compound in the metal deactivator include hydrazide nitrogen compounds, amide nitrogen compounds, triazole nitrogen compounds, and melamine nitrogen compounds.

[0170] As the hydrazide-based nitrogen compound, any nitrogen compound having a hydrazide skeleton may be used, and examples thereof include dodecanedioic acid bis[N2-(2-hydroxybenzoyl)hydrazide], N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazide, decanedicarboxylic acid disalicylic hydrazide, N-salicylic-N'-salicylic hydrazide, m-nitrophenyl hydrazide, 3-aminophthalhydrazide, phthalic acid dihydrazide, adipic acid hydrazide, oxalyl di(2-hydroxy-5-octylbenzylidene hydrazide), N'-benzoylpyrrolidonecarboxylic acid hydrazide, and N,N'-bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hydrazide.

[0171] The amide nitrogen compound may be any nitrogen compound having an amide skeleton, and examples thereof include N,N′-bis{2-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethyl}oxalamide.

[0172] The triazole nitrogen compound may be any nitrogen compound having a triazole skeleton, and examples thereof include N-(2H-1,2,4-triazol-5-yl)salicylamide, 3-amino-1,2,4-triazole, and 3-(N-salicyloyl)amino-1,2,4-triazole.

[0173] As the melamine-based nitrogen compound, any nitrogen compound having a melamine skeleton may be used, and examples thereof include melamine, melamine derivatives, etc. More specifically, examples thereof include triaminotriazine, alkylated triaminotriazine, alkoxyalkylated triaminotriazine, melamine, alkylated melamine, alkoxyalkylated melamine, N2-butylmelamine, N2,N2-diethylmelamine, N,N,N',N',N",N"-hexa(methoxymethyl)melamine, etc.

[0174] The metal deactivator preferably contains bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionic acid][ethylenebis(oxyethylene)].

[0175] Surfactants

[0176] Examples of the surfactant include nonionic surfactants and weakly cationic surfactants.

[0177] Examples of the nonionic surfactant include polyethylene glycol, polyethylene glycol-polypropylene glycol copolymers, aliphatic alcohol polyoxyethylene adducts, aromatic alcohol polyoxyethylene adducts, and polyhydric alcohol polyoxyethylene adducts.

[0178] Examples of the weak cationic surfactant include terminal diamine polyethylene glycol, terminal diamine polyethylene glycol-polypropylene glycol copolymer, aliphatic amine polyoxyethylene adducts, aromatic amine polyoxyethylene adducts, and polyamine polyoxyethylene adducts.

[0179] Examples of surfactants other than those described above include polyoxyalkylene acetylene glycols, polyoxyalkylene glycerol ethers, polyoxyalkylene alkyl ethers, polyoxyalkylene esters, polyoxyalkylene alkylamines, and polyoxyalkylene alkylamides.

[0180] One embodiment of the soldering flux of the first embodiment described above contains rosin, terpene phenol resin, an organic acid (A1) having an SP value of 11.00 or more, and a solvent, and is suitable for flow soldering.

[0181] The specific organic acid (A1) is highly active and easily precipitates in the flux residue. However, even if the flux of the present embodiment contains the organic acid (A1), by containing a terpene-phenol resin having a hydroxyl value exceeding 70 mgKOH / g in addition to the rosin, the precipitation of the organic acid (A1) in the flux residue after soldering can be further suppressed.

[0182] The reason why such an effect can be obtained is not clear, but it is presumed that the compatibility of the organic acid (A1) with the resin component in the flux residue is improved by the terpene phenol resin having a hydroxyl value exceeding 70 mgKOH / g contained in the flux of the present embodiment.

[0183] [Second method]

[0184] One embodiment of the soldering flux of the second aspect is as follows: The soldering flux of this embodiment contains rosin, terpene phenol resin, an activator, a solvent (S), and other components as needed.

[0185] The terpene phenol resin has a hydroxyl value exceeding 70 mgKOH / g. The activator contains an organic acid (A2) represented by the following general formula (1). The soldering flux of this embodiment is suitable as a soldering flux for flow soldering.

[0186] R 1 -COOH···(1)

[0187] [Where R 1 represents a chain hydrocarbon group having 2 to 15 carbon atoms, an alicyclic hydrocarbon group having 3 to 15 carbon atoms, an aromatic group or a carboxyl group. The chain hydrocarbon group and the alicyclic hydrocarbon group each have a hydroxyl group or a carboxyl group.]

[0188] <Rosin>

[0189] Examples of the rosin include the rosin described above in the first aspect.

[0190] The rosin may be used alone or in combination of two or more.

[0191] As the rosin, a rosin derivative is preferably used.

[0192] As the rosin derivative, it is preferable to use one or more selected from the group consisting of acid-modified hydrogenated rosin, acid-modified rosin, hydrogenated rosin, polymerized rosin and rosin ester.

[0193] As the acid-modified hydrogenated rosin, acrylic acid-modified hydrogenated rosin is preferably used.

[0194] As the acid-modified rosin, acrylic acid-modified rosin is preferably used.

[0195] The content of the rosin in the flux is preferably 1% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 25% by mass or less, and further preferably 2% by mass or more and 20% by mass or less, relative to the total amount of the flux (100% by mass).

[0196] In the solid content of the flux, the content of the rosin is preferably 10% by mass or more and 90% by mass or less, more preferably 20% by mass or more and 80% by mass or less, and further preferably 30% by mass or more and 75% by mass or less, relative to the total amount (100% by mass) of the solid content.

[0197] <Terpene phenol resin>

[0198] Examples of the terpene-phenol resin include the terpene-phenol resins described above in the first aspect.

[0199] The terpene phenol resins may be used alone or in combination of two or more.

[0200] The hydroxyl value of the terpene phenol resin exceeds 70 mgKOH / g, may be 90 mgKOH / g or more, preferably 110 mgKOH / g or more, more preferably 130 mgKOH / g or more, further preferably 140 mgKOH / g or more, particularly preferably 170 mgKOH / g or more, and most preferably 190 mgKOH / g or more.

[0201] The upper limit of the hydroxyl value of the terpene phenol resin is not particularly limited as long as the effects of the present invention are exhibited, and may be, for example, 300 mgKOH / g or less, 250 mgKOH / g or less, or 230 mgKOH / g or less.

[0202] For example, the hydroxyl value of the terpene-phenol resin may be greater than 70 mgKOH / g and less than 300 mgKOH / g, may be greater than 90 mgKOH / g and less than 300 mgKOH / g, preferably greater than 110 mgKOH / g and less than 300 mgKOH / g, more preferably greater than 130 mgKOH / g and less than 300 mgKOH / g, further preferably greater than 140 mgKOH / g and less than 300 mgKOH / g, particularly preferably greater than 170 mgKOH / g and less than 300 mgKOH / g, and may be greater than 190 mgKOH / g and less than 300 mgKOH / g.

[0203] Alternatively, the hydroxyl value of the terpene-phenol resin may be greater than 70 mgKOH / g and less than 250 mgKOH / g, may be greater than 90 mgKOH / g and less than 250 mgKOH / g, preferably greater than 110 mgKOH / g and less than 250 mgKOH / g, more preferably greater than 130 mgKOH / g and less than 250 mgKOH / g, further preferably greater than 140 mgKOH / g and less than 250 mgKOH / g, particularly preferably greater than 170 mgKOH / g and less than 250 mgKOH / g, and may be greater than 190 mgKOH / g and less than 250 mgKOH / g.

[0204] When the hydroxyl value of the terpene phenol resin is equal to or greater than the above lower limit, precipitation of the organic acid (A1) in the flux residue after soldering can be further suppressed.

[0205] When the hydroxyl value of the terpene phenol resin is equal to or less than the above upper limit, moisture absorption can be further reduced, thereby further suppressing a decrease in the insulation resistance value of the soldering flux and further suppressing the occurrence of migration.

[0206] The content of the terpene phenol resin in the soldering flux is preferably 0.1% to 20% by mass, more preferably 0.2% to 10% by mass, and further preferably 0.5% to 5% by mass, relative to the total amount of the soldering flux (100% by mass).

[0207] In the solid content of the flux, the content of the terpene phenol resin is preferably 3 mass % or more and 50 mass % or less, more preferably 4 mass % or more and 40 mass % or less, and further preferably 5 mass % or more and 30 mass % or less, relative to the total amount of the solid content (100 mass %).

[0208] When the content of the terpene-phenol resin is equal to or greater than the above lower limit, precipitation of the activator in the flux residue after soldering can be further suppressed.

[0209] When the content of the terpene phenol resin is equal to or less than the above upper limit, the possibility that the viscosity of the flux becomes too high can be reduced.

[0210] The mixing ratio of rosin and terpene-phenol resin, in terms of the mass ratio of rosin / terpene-phenol resin, i.e., the ratio of the content of rosin to the content of terpene-phenol resin, is preferably 0.5 to 20, more preferably 1 to 10, and even more preferably 1.5 to 8.

[0211] <Activator>

[0212] 《Special active agent》

[0213] The soldering flux of the present embodiment contains an organic acid (A2) represented by the following general formula (1) as a specific activator.

[0214] R 1 -COOH···(1)

[0215] [Where R 1 represents a chain hydrocarbon group having 2 to 15 carbon atoms, an alicyclic hydrocarbon group having 3 to 15 carbon atoms, an aromatic group or a carboxyl group. The chain hydrocarbon group and the alicyclic hydrocarbon group each have a hydroxyl group or a carboxyl group.]

[0216] R 1 The chain hydrocarbon group in may be either linear or branched.

[0217] The chain hydrocarbon group and the alicyclic hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group, and are preferably saturated hydrocarbon groups.

[0218] The number of carbon atoms in the chain hydrocarbon group is preferably 2-12, more preferably 3-9, particularly preferably 3-7, and most preferably 3-5.

[0219] Examples of the chain hydrocarbon group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, tert-pentyl, neopentyl, n-hexyl, isohexyl, sec-hexyl, tert-hexyl and neohexyl.

[0220] The alicyclic hydrocarbon group preferably has 3 to 12 carbon atoms, more preferably 4 to 12 carbon atoms, and even more preferably 4 to 8 carbon atoms.

[0221] Examples of the alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, and a cycloundecyl group.

[0222] R 1The aromatic group in the above-mentioned group is a group having at least one aromatic ring, for example, an aromatic hydrocarbon ring of benzene, naphthalene, anthracene, phenanthrene, etc., an aromatic heterocyclic ring in which a part of the carbon atoms constituting the aromatic hydrocarbon ring are substituted by heteroatoms, a condensed ring formed by condensation of an aromatic hydrocarbon ring and an aromatic heterocyclic ring, etc.

[0223] R 1 When the aromatic group in has a substituent, examples of the substituent include a hydrocarbon group having 1 to 20 carbon atoms, an aromatic hydrocarbon group, a carboxyl group, a hydroxyl group, an amino group, a halogen atom, and the like, preferably a carboxyl group or a hydroxyl group.

[0224] Examples of the organic acid (A2) represented by the general formula (1) include dicarboxylic acids, hydroxycarboxylic acids, and aromatic carboxylic acids.

[0225] Examples of the dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioc acid, hexadecanedioic acid, 2,4-diethylglutaric acid, and 1,3-cyclohexanedicarboxylic acid.

[0226] Examples of the hydroxycarboxylic acid include 2,2-bis(hydroxymethyl)propionic acid and 2,2-bis(hydroxymethyl)butanoic acid.

[0227] Examples of the aromatic carboxylic acid include picolinic acid and dipicolinic acid.

[0228] Among the organic acids (A2) represented by the general formula (1), succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid or 2,2-bis(hydroxymethyl)propionic acid is preferred, succinic acid, glutaric acid, adipic acid or 2,2-bis(hydroxymethyl)propionic acid is more preferred, and succinic acid or 2,2-bis(hydroxymethyl)propionic acid is further preferred.

[0229] The organic acid (A2) represented by the general formula (1) may be used alone or in combination of two or more.

[0230] The content of the organic acid (A2) in the soldering flux is preferably 0.05% by mass to 6% by mass, more preferably 0.1% by mass to 4% by mass, and further preferably 0.1% by mass to 3% by mass, relative to the total mass of the soldering flux (100% by mass).

[0231] In the solid content of the flux, the content of the organic acid (A2) is preferably 0.5 mass % or more and 50 mass % or less, more preferably 0.5 mass % or more and 40 mass % or less, and further preferably 1 mass % or more and 40 mass % or less, relative to the total amount (100 mass %) of the solid content.

[0232] When the content of the organic acid (A2) is equal to or more than the lower limit, the wettability of the flux can be further improved.

[0233] When the content of the organic acid (A2) is equal to or less than the upper limit, precipitation of the activator in the flux residue after soldering can be further suppressed.

[0234] The mixing ratio of the organic acid (A2) and the terpene-phenol resin, measured by the mass ratio represented by organic acid (A2) / terpene-phenol resin, that is, the ratio of the organic acid (A2) to the content (100 parts by mass) of the terpene-phenol resin, can be 1 part by mass or more and 600 parts by mass or less, preferably 2 parts by mass or more and 600 parts by mass or less, more preferably 1 part by mass or more and 400 parts by mass or less, further preferably 1 part by mass or more and 200 parts by mass or less, particularly preferably 1 part by mass or more and 100 parts by mass or less, and most preferably 1 part by mass or more and 50 parts by mass or less.

[0235] When the content ratio of the organic acid (A2) is equal to or more than the above lower limit, weldability can be improved.

[0236] When the content ratio of the organic acid (A2) is equal to or less than the above upper limit, precipitation of the organic acid (A2) in the flux residue after soldering can be further suppressed.

[0237] Other active agents

[0238] Examples of the other active agent include the active agents described above in the first aspect.

[0239] <Solvent (S)>

[0240] Examples of the solvent (S) include the solvents described above in the first embodiment.

[0241] The solvent (S) may be used alone or in combination of two or more.

[0242] From the viewpoint of improving volatility during preheating, the solvent (S) preferably contains a solvent (S1) having a boiling point of 100° C. or less. The boiling point of the solvent (S1) is preferably 60° C. or more and 100° C. or less, more preferably 70° C. or more and 100° C. or less, further preferably 75° C. or more and 100° C. or less, and particularly preferably 80° C. or more and 100° C. or less.

[0243] The content of the solvent (S1) is preferably 70% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, further preferably 90% by mass or more and 100% by mass or less, particularly preferably 95% by mass or more and 100% by mass or less, and may be 100% by mass, relative to the total mass (100% by mass) of the solvent (S). When the content of the solvent (S1) is above the lower limit, the volatility of the solvent (S) under preheating is easily increased.

[0244] The alcohol solvent preferably contains 2-propanol.

[0245] The content of the solvent (S) in the flux is preferably 40% by mass or more and 98% by mass or less, more preferably 60% by mass or more and 98% by mass or less, and further preferably 70% by mass or more and 98% by mass or less, relative to the total amount of the flux (100% by mass).

[0246] <Other ingredients>

[0247] As other components, the components described above in the first embodiment can be mentioned.

[0248] One embodiment of the soldering flux of the second embodiment described above contains rosin, terpene phenol resin, the organic acid (A2) represented by the above general formula (1), and a solvent, and is suitable for flow soldering.

[0249] The specific organic acid (A2) is highly active and is easily precipitated in the flux residue. However, even if the flux of the present embodiment contains the organic acid (A2), by containing a terpene-phenol resin having a hydroxyl value exceeding 70 mgKOH / g in addition to the rosin, the precipitation of the organic acid (A2) in the flux residue after soldering can be further suppressed.

[0250] The reason why such an effect can be obtained is not clear, but it is presumed that the compatibility of the organic acid (A2) with the resin component in the flux residue is improved by the terpene phenol resin having a hydroxyl value exceeding 70 mgKOH / g contained in the flux of the present embodiment.

[0251] (Method for preparing a conjugate)

[0252] The method for producing a joined body according to the third aspect includes the step of obtaining a joined body by soldering a solder alloy on the surface of a substrate treated with the flux according to the first aspect or the second aspect.

[0253] Hereinafter, one embodiment of the method for producing a joined body according to the third aspect will be described.

[0254] The method for producing a bonded body according to the present embodiment is a method that includes a component mounting step, a flux coating step, a preheating step, and a soldering step in sequence.

[0255] In the component mounting step, components are mounted on the substrate.

[0256] Examples of the substrate include a printed wiring board and the like.

[0257] Examples of the components include integrated circuits, transistors, diodes, resistors, capacitors, and the like.

[0258] In the flux application step, the flux of the above-described embodiment is applied to the soldering surface of the substrate on which components are mounted.

[0259] As the flux coating apparatus, there can be mentioned a spray flux coater, a foaming flux coater, etc. Among them, a spray flux coater is preferred from the viewpoint of the stability of the coating amount.

[0260] From the viewpoint of solderability, the amount of flux applied is preferably 30 to 180 mL / m 2 , more preferably 40 to 150 mL / m 2 , particularly preferably 50 to 120 mL / m 2 .

[0261] In the soldering process, the soldering surface of the substrate on which the components are mounted is brought into contact with molten solder formed by melting a solder alloy.

[0262] The method of bringing the molten solder into contact with the soldering surface is not particularly limited as long as it is a method that can bring the molten solder into contact with the substrate. Examples of such a method include a jet method and a dipping method.

[0263] The jet method is a method of bringing the soldering surface of a substrate on which components are mounted into contact with a jet of molten solder. The immersion method is a method of bringing the soldering surface of a substrate on which components are mounted into contact with a stationary liquid surface of molten solder.

[0264] As the solder alloy, a solder alloy having a known composition can be used.

[0265] The solder alloy can also be a solder of Sn alone, or a solder alloy of Sn-Ag, Sn-Cu, Sn-Ag-Cu, Sn-Bi, Sn-In, etc., or a solder alloy to which Sb, Bi, In, Cu, Zn, As, Ag, Cd, Fe, Ni, Co, Au, Ge, P, etc. are added.

[0266] The solder alloy may be a Sn-Pb based solder alloy or a Sn-Pb based solder alloy to which Sb, Bi, In, Cu, Zn, As, Ag, Cd, Fe, Ni, Co, Au, Ge, P, etc. are added.

[0267] The solder alloy is preferably a Pb-free solder.

[0268] The soldering conditions in the soldering step may be appropriately set according to the melting point of the solder. For example, when a Sn-Ag-Cu solder alloy is used, the temperature of the molten solder is preferably 230 to 280°C, more preferably 250 to 270°C.

[0269] In the preheating step, the substrate on which the components are mounted is preheated. The temperature of the heated substrate in the preheating step is preferably 80 to 130°C, and more preferably 90 to 120°C.

[0270] According to the method for producing a bonded body of the present embodiment described above, it is possible to further suppress the precipitation of the activating agent in the flux residue on the obtained bonded body, thereby reducing the possibility of migration in the obtained bonded body.

[0271] Other implementations:

[0272] The flux of the above-mentioned embodiment is suitable for flow soldering, but the flux of the first and second embodiments is not limited thereto, and can also be used for reflow soldering.

[0273] Example

[0274] Hereinafter, the present invention will be described by way of examples, but the present invention is not limited to the following examples.

[0275] <Preparation of mixed solution>

[0276] (Test Examples 1 to 35)

[0277] The mixed solutions of the test examples were prepared in the compositions shown in Tables 1 to 7. In Tables 1 to 7, the numerical values ​​represent the weight (g) of each component.

[0278] The raw materials used are as follows.

[0279] Active Agent:

[0280] 2,2-Bis(hydroxymethyl)propionic acid (SP value: 16.12)

[0281] Succinic acid (SP value: 13.21)

[0282] Glutaric acid (SP value: 12.61)

[0283] Adipic acid (SP value: 12.15)

[0284] Suberic acid (SP value: 11.49)

[0285] Sebacic acid (SP value: 11.04)

[0286] 4-tert-Butylbenzoic acid (SP value: 10.52)

[0287] Terpene phenol resin:

[0288] Resin A 200±10mgKOH / g

[0289] Resin B 150±10mgKOH / g

[0290] Resin C 120±10mgKOH / g

[0291] Resin D 100±10mgKOH / g

[0292] Resin E 60±10mgKOH / g

[0293] <Evaluation>

[0294] 《Evaluation of the solubility of active agents》

[0295] Add the activator to resins A to E to prepare a mixed solution. Heat the mixed solution to a temperature above the softening point of the resin and then cool it to room temperature. Check whether there is precipitate in the mixed solution during heating and after cooling, and evaluate based on the following criteria. The results are shown in Tables 1 to 7.

[0296] Judgment criteria:

[0297] A: The activator was dissolved in the mixed solution by heating, and no precipitate was observed after cooling.

[0298] B: The activator did not dissolve in the mixed solution even when heated, and precipitates were observed after cooling.

[0299] [Table 1]

[0300]

[0301] As shown in Table 1, in Test Examples 1 and 2 containing succinic acid and either Resin A or Resin B, no precipitate was observed after cooling.

[0302] On the other hand, in Test Examples 3 to 5 containing succinic acid and any one of Resins C to E, precipitates were observed after cooling.

[0303] [Table 2]

[0304]

[0305] As shown in Table 2, in Test Example 6 containing glutaric acid and resin A, no precipitate was observed after cooling.

[0306] On the other hand, in Test Examples 7 to 10 containing glutaric acid and any one of Resins B to E, precipitates were observed after cooling.

[0307] [Table 3]

[0308]

[0309] As shown in Table 3, in Test Example 11 containing adipic acid and resin A, no precipitate was observed after cooling.

[0310] On the other hand, in Test Examples 12 to 15 containing adipic acid and any one of the polymers B to E, precipitates were observed after cooling.

[0311] [Table 4]

[0312]

[0313] As shown in Table 4, in Test Examples 16 to 19 containing suberic acid and any one of Resins A to D, no precipitate was observed after cooling.

[0314] On the other hand, in Test Example 20 containing suberic acid and Resin E, precipitates were observed after cooling.

[0315] [Table 5]

[0316]

[0317] As shown in Table 5, in Test Examples 21 to 24 containing sebacic acid and any of Resins A to D, no precipitate was observed after cooling.

[0318] On the other hand, in Test Example 25 containing sebacic acid and Resin E, precipitates were observed after cooling.

[0319] [Table 6]

[0320]

[0321] As shown in Table 6, in Test Examples 26 and 27 containing 2,2-bismethylolpropionic acid and either the resin A or the resin B, no precipitate was observed after cooling.

[0322] On the other hand, in Test Examples 28 to 30 containing 2,2-bismethylolpropionic acid and any one of Resins C to E, precipitates were observed after cooling.

[0323] [Table 7]

[0324]

[0325] As shown in Table 7, in Test Examples 31 to 35 containing 4-tert-butylbenzoic acid and any one of Resins A to E, no precipitate was observed after cooling.

[0326] From the above results, it is understood that the organic acid (A1) having an SP value of 11.00 or more and the organic acid (A2) represented by the above general formula (1) are dissolved by selecting a terpene-phenol resin having a hydroxyl value exceeding 70 mgKOH / g.

[0327] It was also found that the organic acid (A1) having an SP value of 11.00 or more and the organic acid (A2) represented by the above general formula (1) could not be dissolved in the terpene-phenol resin having a hydroxyl value of 70 mgKOH / g or less.

[0328] <Preparation of flux>

[0329] (Examples 1 to 23, Comparative Examples 1 to 2, Reference Examples 1 to 2)

[0330] The soldering fluxes of Examples and Comparative Examples were prepared according to the compositions shown in the following Table 7. The compositions in Table 7 are expressed in mass % when the total amount of the soldering flux is 100 mass %.

[0331] Specific active agents:

[0332] 2,2-Bis(hydroxymethyl)propionic acid (SP value: 16.12)

[0333] Succinic acid (SP value: 13.21)

[0334] Glutaric acid (SP value: 12.61)

[0335] Adipic acid (SP value: 12.15)

[0336] Suberic acid (SP value: 11.49)

[0337] Sebacic acid (SP value: 11.04)

[0338] 4-tert-Butylbenzoic acid (SP value: 10.52)

[0339] Terpene phenol resin:

[0340] Resin A 200±10mgKOH / g

[0341] Resin B 150±10mgKOH / g

[0342] Resin C 120±10mgKOH / g

[0343] Resin D 100±10mgKOH / g

[0344] Resin E 60±10mgKOH / g

[0345] Rosin: Acrylic acid modified hydrogenated rosin, acrylic acid modified rosin, hydrogenated rosin, polymerized rosin, rosin ester

[0346] Solvent: 2-Propanol

[0347] Other resin components: Silicone resin

[0348] Antioxidants: Quinoline compounds

[0349] <Preparation of molten solder>

[0350] As a mother alloy, an ingot composed of an alloy containing 3 mass % of Ag, 0.5 mass % of Cu, and the balance of Sn was prepared.

[0351] The ingot is melted to prepare molten solder.

[0352] <Evaluation>

[0353] 《Precipitation of flux residue on the surface》

[0354] Verification method:

[0355] By spraying the flux of each example onto the substrate, a pre-treated substrate was obtained.

[0356] Next, flow soldering is performed by bringing molten solder into contact with the pre-treated substrate in a nitrogen atmosphere.

[0357] The presence or absence of precipitation of flux residue on the surface of the substrate was confirmed, and evaluation was performed based on the following criteria. The results are shown in Tables 8 to 10.

[0358] Judgment criteria:

[0359] A: No precipitate was observed on the surface of the flux residue.

[0360] B: A small amount of precipitates was observed on the surface of the flux residue.

[0361] C: A large amount of precipitates were observed on the surface of the flux residue.

[0362] In the evaluation results, the amount of precipitates on the surface of the flux residue increases in order from A to C. The fluxes with evaluation results A to B are acceptable, and the flux with evaluation result C is unacceptable.

[0363] [Table 8]

[0364]

[0365] [Table 9]

[0366]

[0367] [Table 10]

[0368]

[0369] The fluxes of Examples 1 to 23 containing a highly active specific organic acid and a terpene-phenol resin having a hydroxyl value exceeding 70 mgKOH / g were evaluated as A or B in terms of precipitation of flux residue on the surface.

[0370] On the other hand, the fluxes of Comparative Examples 1 and 2 containing a highly active specific organic acid and a terpene-phenol resin having a hydroxyl value of 70 mgKOH / g or less were evaluated as C for the precipitation of flux residue on the surface.

[0371] In addition, the flux of Reference Example 2 containing an organic acid and a terpene-phenol resin having low activity was rated A for precipitation of flux residue on the surface even though the hydroxyl value of the terpene-phenol resin was 70 mgKOH / g or less.

[0372] That is, according to the present invention, even when a highly active specific organic acid is contained, precipitation in the flux residue can be suppressed by containing a terpene-phenol resin having a hydroxyl value exceeding 70 mgKOH / g.

[0373] Industrial Applicability

[0374] According to the present invention, a soldering flux and a method for preparing a joint body can be provided, which can further suppress the precipitation of an active agent in the soldering flux residue after soldering. The soldering flux is suitable for flow soldering. In addition, the soldering flux can be used for soldering electronic substrates used in a high temperature and high humidity environment.

Claims

1. A soldering flux comprising rosin, terpene phenol resin and an activator, The terpene phenol resin has a hydroxyl value of 140 mgKOH / g or more, The activator contains an organic acid (A1) having a solubility parameter (SP value) of 12.00 or more.

2. The soldering flux according to claim 1, wherein The content of the organic acid (A1) is 0.05 mass % or more and 6 mass % or less relative to the total mass (100 mass %) of the soldering flux.

3. The soldering flux according to claim 1 or 2, wherein The ratio (mass ratio) of the content of the organic acid (A1) relative to the content (100 parts by mass) of the terpene-phenol resin is 1 part by mass or more and 600 parts by mass or less.

4. A soldering flux comprising rosin, terpene phenol resin and an activator, The terpene phenol resin has a hydroxyl value of 140 mgKOH / g or more, The active agent contains one or more organic acids (A2) selected from oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, 2,4-diethylglutaric acid, 1,3-cyclohexanedicarboxylic acid, 2,2-bis(hydroxymethyl)propionic acid, 2,2-bis(hydroxymethyl)butyric acid, picolinic acid and dipicolinic acid.

5. The soldering flux according to claim 4, wherein The content of the organic acid (A2) is 0.05% by mass or more and 6% by mass or less relative to the total mass (100% by mass) of the soldering flux.

6. The soldering flux according to claim 4 or 5, wherein: The ratio (mass ratio) of the content of the organic acid (A2) relative to the content (100 parts by mass) of the terpene-phenol resin is 1 part by mass or more and 600 parts by mass or less.

7. The soldering flux according to claim 4 or 5, wherein: The content of the terpene phenol resin is 0.1% by mass or more and 20% by mass or less relative to the total mass (100% by mass) of the soldering flux.

8. The soldering flux according to claim 1 or 2, wherein: The content of the terpene phenol resin is 0.1% by mass or more and 20% by mass or less relative to the total mass (100% by mass) of the soldering flux.

9. A method for preparing a conjugate, comprising: A process for obtaining a joint body by soldering a solder alloy on the surface of a substrate treated with the flux according to any one of claims 1 to 8.

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