JP2020142266A - Flux and solder paste - Google Patents

Abstract

To provide a flux which imparts thixotropic properties and is excellent in printability, printing sag suppression capability and heating sag suppression capability and enhances wettability of soldering, and a solder paste using the flux.SOLUTION: A flux contains a thixotropic agent, a compound represented by general formula (1), a rosin and a solvent, in which the thixotropic agent contains a cyclic amide compound and a non-cyclic amide compound, contains 0.1 wt.% to 8.0 wt.% of the cyclic amide compound, 0.5 wt.% to 8.0 wt.% of the non-cyclic amide compound, and has the total amount of the cyclic amide compound and the non-cyclic amide compound of 1.5 wt.% or more and 10.0 wt.% or less. The cyclic amide compound is obtained by cyclic polycondensation of a dicarboxylic acid and/or tricarboxylic acid and diamine and/or triamine. The non-cyclic amide compound is obtained by non-cyclic polycondensation of a monocarboxylic acid, dicarboxylic acid and/or tricarboxylic acid and monoamine, diamine and/or triamine. In formula (1), R1, R2, R3 and R4 represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.SELECTED DRAWING: None

Description

The present invention relates to a flux used for soldering and a solder paste using this flux.

Generally, the flux used for soldering chemically removes metal oxides present on the metal surface of the solder and the object to be soldered, allowing the movement of metal elements at the boundary between the two. Has the effect of soldering. Therefore, by performing soldering using flux, an intermetallic compound can be formed between the solder and the metal surface of the object to be bonded, and a strong bond can be obtained.

In such a soldering flux and a solder paste containing metal powder, thixotropy is imparted by the thixotropic agent contained in the flux. The thixotropic agent builds a network in the flux and imparts thixotropic properties. If the flux has thixotropic properties, the viscosity of the flux decreases when a shearing force is applied, so that workability such as printability is improved. In addition, by containing the thixotropy, the dripping of the solder paste after printing, which is called printing dripping, and the dripping of the solder paste when melting by heating, which is called heating dripping, are held by the network formed by the thixotropy, so that the flux The sagging is suppressed.

As the thixo agent, an amide-based thixo agent composed of an amide compound obtained by dehydration condensation of a fatty acid and an amine is used from the viewpoint of imparting tixo property, improving printability, and suppressing printing sagging and heating sagging (for example, Patent Documents). 1). Further, as the thixotropy, an ester-based thixotropy made of hydrogenated castor oil is used.

Japanese Patent No. 3350767

In the amide-based thixo agent, hydrogen bonds are easily formed in the molecule and between the molecules by the amide bond, and when it becomes a polymer, the compatibility is poor and uniform dispersion is difficult, so that the printability is not stable. Further, when the amount of the high molecular weight amide compound is increased, the viscosity becomes extremely high, so that the printability deteriorates. Further, even an ester thixotropy cannot sufficiently suppress heating sagging. In addition, there is also a problem that the wettability of the metal surface of the object to be joined due to solder tends to decrease.

INDUSTRIAL APPLICABILITY The present invention has been made to solve such a problem, and has improved the wettability of solder by imparting chicosis, excellent printability, ability to suppress print sagging, and ability to suppress heat sagging. It is an object of the present invention to provide a flux and a solder paste using the flux.

A flux containing a thixo agent composed of a cyclic amide compound and a non-cyclic amide compound and a specific activator represented by the general formula (1) improves the tixo property and the wettability of the solder, and this flux It was found that the solder paste containing the metal powder can improve the printability and suppress the printing sagging and the heating sagging.

Therefore, the present invention is a flux containing a thixo agent, a compound represented by the following general formula (1), a rosin, and a solvent, and the thixo agent contains a cyclic amide compound and a non-cyclic amide compound. , 0.1 wt% or more and 8.0 wt% or less of the cyclic amide compound, 0.5 wt% or more and 8.0 wt% or less of the acyclic amide compound, and the cyclic amide compound and the acyclic amide compound. The total is 1.5 wt% or more and 10.0 wt% or less, and the cyclic amide compound is an amide compound having a molecular weight of 3000 or less in which dicarboxylic acid and / or tricarboxylic acid and diamine and / or triamine are cyclically polycondensed. The acyclic amide compound is an amide compound in which a monocarboxylic acid, a dicarboxylic acid and / or a tricarboxylic acid and a monoamine, a diamine and / or a triamine are acyclically condensed.

［式（１）中、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４は、それぞれ独立に、水素原子または炭素数１〜４のアルキル基を示す。］

[In formula (1), R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ]

The compound represented by the general formula (1) is preferably picolinic acid.

It is more preferable that the cyclic amide compound has 3 or more and 10 or less carbon atoms of the dicarboxylic acid and tricarboxylic acid, and the cyclic amide compound has 6 or more and 10 or less carbon atoms of the dicarboxylic acid and tricarboxylic acid.

It is more preferable that the cyclic amide compound has 2 or more and 54 or less carbon atoms of diamine and triamine, and the cyclic amide compound has 6 carbon atoms of diamine and triamine.

The cyclic amide compound is preferably an amide compound in which a dicarboxylic acid having 3 or more and 10 or less carbon atoms and a diamine having 2 or more and 54 carbon atoms or less are cyclically polycondensed, and the cyclic amide compound has carbon atoms. It is more preferable that the amide compound is a cyclic polycondensation of a dicarboxylic acid having a value of 6 or more and 10 or less and a diamine having 6 carbon atoms.

The acyclic amide compound preferably has a monocarboxylic acid, a dicarboxylic acid and a tricarboxylic acid having a carbon number of 2 or more and 28 or less, and a monoamine, a diamine and a triamine having a carbon number of 0 or more and 54 or less.

The thixotropy preferably further contains an ester compound, and the thixotropy preferably contains hydrogenated castor oil as an ester compound.

It is more preferable that the thixotropy contains 0.1 wt% or more and 1.5 wt% or less of the cyclic amide compound and 0.5 wt% or more and 4.0 wt% or less of the acyclic amide compound. Further, the thixotropy preferably contains the ester compound in an amount of 0 wt% or more and 8.0 wt% or less.

Further, the compound represented by the general formula (1) is preferably contained in an amount of 0.5 wt% or more and 7.0 wt% or less, and the rosin is preferably contained in an amount of 30 wt% or more and 60 wt% or less.

Further, it may contain 0 wt% or more and 20 wt% or less of amine, 0 wt% or more and 5 wt% or less of organic halogen compound, 0 wt% or more and 2 wt% or less of amine halide hydrolate, or 0 wt% or more and 5 wt% or less of antioxidant. preferable.

Further, the present invention is a solder paste containing the above-mentioned flux and metal powder.

In the thixo agent composed of the cyclic amide compound and the acyclic amide compound, the acyclic amide compound is crosslinked with the low molecular weight cyclic amide compound, and therefore, in the flux of the present invention, the comparison with the case where the thixo agent is composed of the acyclic amide compound. Therefore, the thixo property can be improved and the precipitation of the thixo agent can be suppressed without increasing the content of the acyclic amide compound.

Further, in the flux of the present invention, the wettability of the solder can be enhanced by containing the compound represented by the above general formula (1) as the specific activator.

In the solder paste using this flux, it is possible to obtain good printability in which bleeding, blurring and the like are suppressed, and it is possible to suppress printing sagging in which the solder paste flows after printing. Further, it is possible to prevent the solder paste from sagging due to heating during soldering.

It is a schematic diagram which shows the outline of the molecular structure of a dicarboxylic acid. It is a schematic diagram which shows the outline of the molecular structure of a diamine. It is a schematic diagram which shows the outline of the molecular structure of the acyclic amide compound. It is a schematic diagram which shows the outline of the molecular structure of the acyclic amide compound. It is a schematic diagram which shows the outline of the molecular structure of a cyclic amide compound. It is a schematic diagram which shows the outline of the molecular structure which crosslinked a non-cyclic amide compound with a cyclic amide compound. It is a schematic diagram which shows the outline of the molecular structure of a monocarboxylic acid. It is a schematic diagram which shows the outline of the molecular structure of a monoamine. It is a schematic diagram which shows the outline of the molecular structure of the acyclic amide compound which condensed monocarboxylic acid and monoamine.

<Example of flux of this embodiment>
The flux of the present embodiment contains a thixotropic agent, a compound represented by the general formula (1), rosin, and a solvent. The thixotropy comprises a cyclic amide compound and a non-cyclic amide compound.

The cyclic amide compound is a low molecular weight amide compound having a molecular weight of 3000 or less, particularly 1000 or less, in which a dicarboxylic acid and / or a tricarboxylic acid and a diamine and / or a triamine are cyclically polycondensed. The acyclic amide compound is an acyclic amide oligomer having a molecular weight of 3000 or less, which is a non-cyclic polycondensation of a monocarboxylic acid, a dicarboxylic acid and / or a tricarboxylic acid, and a monoamine, a diamine and / or a triamine, and a molecular weight of more than 3000. It is a non-cyclic polymer amide polymer.

FIG. 1 is a schematic diagram showing an outline of the molecular structure of a dicarboxylic acid, FIG. 2 is a schematic diagram showing an outline of the molecular structure of a diamine, and FIG. 3 is a schematic diagram showing an outline of the molecular structure of an acyclic amide compound. .. By polycondensing (dehydrating condensation) the dicarboxylic acid shown in FIG. 1 and the diamine shown in FIG. 2, an acyclic amide compound is synthesized as shown in FIG.

In the thixo agent composed of the acyclic amide compound shown in FIG. 3, the carboxyl group (COOH) of the dicarboxylic acid shown in FIG. 1 and the amino group (NH ₂ ) of the diamine shown in FIG. 2 are amide-bonded by polycondensation to form an amide group. A network is formed by hydrogen bonding of C (= O) -NH hydrogen (H) and oxygen (O) within and between molecules. The amide bond site is indicated by (A), and the hydrogen bond site is indicated by (B).

FIG. 4 is a schematic diagram showing an outline of the molecular structure of the acyclic amide compound. When the acyclic amide compound is polymerized, as shown in FIG. 4, hydrogen bonds (B) proceed in the molecule, so that the solubility (compatibility) in the flux becomes very poor, and the acyclic amide compound becomes coarse in the flux. Precipitation may occur, resulting in poor thixophilicity. Further, in the solder paste in which such a flux and a metal powder are mixed, printability is poor, and printing sagging and heating sagging occur.

Therefore, by using the cyclic amide compound in combination with the acyclic amide compound, the non-cyclic amide compound is crosslinked with the cyclic amide compound by a non-covalent interaction to construct a relatively uniform network of thixotropic agent components. , Suppresses excessive thiox agent precipitation.

FIG. 5 is a schematic diagram showing an outline of the molecular structure of the cyclic amide compound. By polycondensing the dicarboxylic acid shown in FIG. 1 and the diamine shown in FIG. 2, a cyclic amide compound is synthesized as a low molecular weight amide as shown in FIG.

Since the cyclic amide compound has higher symmetry than the acyclic amide compound, it has a property of being easily crystallized as compared with the acyclic low molecular weight amide. On the other hand, since the acyclic low molecular weight amide has a polar terminal group, it is easily compatible with the flux and difficult to crystallize, so that it is difficult to impart thixotropic property due to network formation. On the other hand, since the cyclic amide compound does not have a polar terminal group, it is difficult to be compatible with the flux and it is easy to impart thixotropic property due to network formation.

As a result, in the thixo agent composed of the cyclic amide compound and the acyclic amide compound, the hydrogen bond between the cyclic amide compound and the acyclic amide compound is promoted, and the hydrogen bond in the molecule of the acyclic amide compound is inhibited. It is thought that it will be done.

FIG. 6 is a schematic diagram showing an outline of a molecular structure in which a non-cyclic amide compound is crosslinked with a cyclic amide compound. In the thixo agent composed of the cyclic amide compound and the acyclic amide compound, as shown in FIG. 6, the cyclic amide compound and the acyclic amide compound are hydrogen-bonded (B), so that the cyclic amide compound is a non-cyclic amide compound. It is considered that a network of relatively uniform components bridged by covalent interactions is constructed.

Therefore, in the flux containing the thixotropic agent composed of the cyclic amide compound and the acyclic amide compound, the excessive precipitation of the thixotropic agent is suppressed and the thixotropic property is excellent as compared with the thixotropic agent composed of the cyclic amide compound. Further, the solder paste composed of a flux containing a thixo agent composed of a cyclic amide compound and a non-cyclic amide compound and a metal powder is excellent in printability, suppresses printing sagging, and further suppresses heating sagging.

Cyclic amide compounds and acyclic amide compounds are represented as [n + n] type when the number of carboxylic acids is n and the number of amines is n. The cyclic amide compound is constructed from the [1 + 1] type to the [n + n] type, preferably the [1 + 1] type to the [3 + 3] type, and particularly preferably the [2 + 2] type. FIG. 5 shows an example of a [2 + 2] type in which a dicarboxylic acid and a diamine are polycondensed cyclically, and the cyclic amide compound is preferably a [2 + 2] type in which a dicarboxylic acid and a diamine are polycondensed cyclically.

The cyclic amide compound is a [2 + 2] type in which tricarboxylic acid and diamine are polycondensed cyclically and one of the functional groups of the tricarboxylic acid is unbonded to another compound, and tricarboxylic acid and diamine are contained. Also included are the [2 + 3] type, which is polycondensed cyclically to form a cage-type structure, and the [3 + 2] type, in which dicarboxylic acid and triamine are polycondensed cyclically to form a cage-type structure.

As a result, the cyclic amide compound includes an amide oligomer in which dicarboxylic acid and diamine are cyclically polycondensed, an amide oligomer in which tricarboxylic acid and diamine are cyclically polycondensed, an amide oligomer in which dicarboxylic acid and triamine are cyclically polycondensed, and tricarboxylic acid. An amide oligomer in which triamine is cyclically polycondensed, an amide oligomer in which dicarboxylic acid and tricarboxylic acid and diamine are cyclically polycondensed, an amide oligomer in which dicarboxylic acid and tricarboxylic acid and triamine are cyclically polycondensed, and a dicarboxylic acid and diamine and triamine are cyclic. It may be any of an amide oligomer polycondensed with, an amide oligomer obtained by cyclically polycondensing tricarboxylic acid, diamine and triamine, and an amide oligomer obtained by cyclically polycondensing dicarboxylic acid and tricarboxylic acid with diamine and triamine.

Further, the acyclic amide compound is an amide compound in which a dicarboxylic acid and / or a tricarboxylic acid and a monoamine are acyclically polycondensed when the monocarboxylic acid and diamine and / or triamine are acyclically polycondensed. In some cases, for example, in the case of an amide compound containing a monocarboxylic acid or a monoamine, the monocarboxylic acid and the monoamine function as terminal molecules to form an acyclic amide oligomer having a reduced molecular weight. Further, the acyclic amide compound is an acyclic polymer-based amide polymer when it is an amidation site in which a dicarboxylic acid and / or a tricarboxylic acid and a diamine and / or a triamine are polycondensed in an acyclic manner. Further, the acyclic amide compound also includes an amide compound in which a monocarboxylic acid and a monoamine are acyclically condensed.

The reason why an amide compound in which a monocarboxylic acid and a monoamine are acyclically condensed can form a network will be described below.

FIG. 7 is a schematic diagram showing an outline of the molecular structure of monocarboxylic acid, FIG. 8 is a schematic diagram showing an outline of the molecular structure of monoamine, and FIG. 9 is a molecule of an acyclic amide compound in which monocarboxylic acid and monoamine are condensed. It is a schematic diagram which shows the outline of the structure.

The carboxyl group (COOH) of the monocarboxylic acid shown in FIG. 7 and the amino group (NH ₂ ) of the monoamine shown in FIG. 8 are amide-bonded by condensation to form the acyclic amide compound shown in FIG. Further, hydrogen (H) and oxygen (O) of the amide group C (= O) -NH of the acyclic amide compound are connected by hydrogen bonding between the molecules. The intramolecular amide bond site of the acyclic amide compound is indicated by (A), and the intermolecular hydrogen bond site of the acyclic amide compound is indicated by (B).

In this way, monoamides (monoamides) having one amide group in the molecule are connected by hydrogen bonds. The aggregate of monoamides formed by hydrogen bonds is treated as a supramolecular. Supramolecules refer to aggregates of molecules constructed from non-covalent interactions such as hydrogen bonds and hydrophobic interactions. Hydrogen bonds show strong interaction and have a stable structure.

Acyclic amide compounds, which are monoamides in which monocarboxylic acids and monoamines are condensed, are linked by hydrogen bond-derived interaction with amide bonds, and in addition, molecular chains linked by hydrogen bond interactions, especially main chain amides. A hydrogen bond derived from the bond and an interaction between molecular chains due to a hydrophobic interaction by a side chain or the like form a bridging site and grow into a three-dimensional network.

As described above, although the acyclic amide compound obtained by condensing a monocarboxylic acid and a monoamine has only one amide group, it can be seen that a network can be formed by binding by a non-covalent interaction by a hydrogen bond.

The cyclic amide compound contained as a thixo agent is an amide compound in which a dicarboxylic acid and / or a tricarboxylic acid and a diamine and / or a triamine are cyclically polycondensed, and has two or more amide groups.

As a result, when the cyclic amide compound is added to the thixo agent, the non-cyclic amide compound, which is an aggregate of monoamides connected by the interaction by hydrogen bonds, is connected via the cyclic amide compound.

In the solder paste using a flux in which the thixotropy contains a cyclic amide compound and a non-cyclic amide compound, it is considered that thixotropic property is imparted by forming a network of the cyclic amide compound and the acyclic amide compound.

However, if the contents of the cyclic amide compound and the non-cyclic amide compound are too small, a sufficient network cannot be formed, so that thixotropic property is not imparted.

On the other hand, in the case of a thixo agent which does not contain a cyclic amide compound or whose content of the cyclic amide compound is less than the amount specified in the present invention, when the acyclic amide compound becomes excessive, the acyclic amide compound is intramolecular or intermolecular. Excessively interacts with each other, and aggregation and precipitation are likely to occur.

As a result, the rheological characteristics of the flux are impaired (printability is poor due to crystal precipitation), and the thixotropic agent density is low in the portion where the aggregate is not formed, so that the thixotropic agent is substantially insufficient as described above. It is thought that it will not be effective.

On the other hand, a cyclic amide compound obtained by cyclically polycondensing dicarboxylic acid and / or tricarboxylic acid, diamine and / or triamine, monocarboxylic acid, dicarboxylic acid and / or tricarboxylic acid, monoamine, diamine and / or triamine. By using the acyclic amide compound condensed in an acyclic manner at the content specified in the present invention, the acyclic amide compound is crosslinked with the cyclic amide compound by a non-covalent interaction, and is relatively uniform. It is possible to construct a network of various tide agent components and suppress excessive tide agent precipitation. The effect of using the cyclic amide compound and the acyclic amide compound in combination is as long as the content of the cyclic amide compound and the acyclic amide compound is within the range specified in the present invention, even if the molecular weight of the acyclic amide compound is 3000 or less. It can be demonstrated even over 3000.

Further, the acyclic amide compound has the maximum molecular weight when the ratio of the total number of moles of the carboxyl groups of the dicarboxylic acid and / or the tricarboxylic acid to the total number of moles of the amino groups of the diamine and / or the triamine is 1: 1. Become. On the other hand, if the ratio of the total number of moles of the carboxyl groups of the dicarboxylic acid and / or the tricarboxylic acid to the total number of moles of the amino groups of the diamine and / or the triamine is 1: m or m: 1 (m> 1). , It becomes an acyclic amide oligomer with a reduced molecular weight. It is preferably 1: 2 to 2: 1.

The cyclic amide compound preferably has a dicarboxylic acid and a tricarboxylic acid having a carbon number of 3 or more and 10 or less, and the dicarboxylic acid and the tricarboxylic acid having a carbon number of 6 or more and 10 or less.

Further, the cyclic amide compound preferably has 2 or more and 54 or less carbon atoms of diamine and triamine, and 6 carbon atoms of diamine and triamine.

Further, the acyclic amide compound preferably has 2 or more and 28 or less carbon atoms of the monocarboxylic acid, dicarboxylic acid and tricarboxylic acid, and more preferably 2 or more carbon atoms of the monocarboxylic acid, dicarboxylic acid and tricarboxylic acid. It is 18 or less, more preferably 2 or more and 10 or less, and even more preferably 6 or more and 10 or less. The acyclic amide compound preferably has a monoamine, diamine, and triamine having 0 or more and 54 or less carbon atoms, and the monoamine, diamine, and triamine have more preferably 0 or more and 18 or less carbon atoms, and further preferably 0 or more and 10 or less carbon atoms. , More preferably 6 or more and 10 or less.

Examples of the dicarboxylic acid in the cyclic amide compound and the non-cyclic amide compound include adipic acid having 6 carbon atoms and sebacic acid having 10 carbon atoms.

The dicarboxylic acids in the cyclic amide compound and the non-cyclic amide compound are malonic acid having 3 carbon atoms, succinic acid having 4 carbon atoms, glutaric acid having 5 carbon atoms, pimelic acid having 7 carbon atoms, and suberic acid having 8 carbon atoms. Examples thereof include aliphatic dicarboxylic acids such as azelaic acid having 9 carbon atoms and cyclohexanedicarboxylic acid having 8 carbon atoms, and aromatic dicarboxylic acids such as phthalic acid having 6 carbon atoms and terephthalic acid having 6 carbon atoms.

Further, examples of the tricarboxylic acid in the cyclic amide compound and the non-cyclic amide compound include cyclohexanetricarboxylic acid having 9 carbon atoms and benzenetricarboxylic acid having 9 carbon atoms.

The monocarboxylic acid in the acyclic amide compound is acetic acid having 2 carbon atoms, palmitic acid having 16 carbon atoms, stearic acid having 18 carbon atoms, 12-hydroxystearic acid having 18 carbon atoms, behenic acid having 22 carbon atoms, and carbon. The number 28, such as montanic acid, can be mentioned.

Examples of the diamine in the cyclic amide compound and the non-cyclic amide compound include 1,6-hexanediamine.

The diamines in the cyclic amide compound and the non-cyclic amide compound are ethylene diamine having 2 carbon atoms, 1,3-diaminopropane having 3 carbon atoms, 1,4-diaminobutane having 4 carbon atoms, dimer diamine having 36 carbon atoms, and carbon. Examples thereof include phenylenediamine having a number of 6, metaxylylenediamine having 8 carbon atoms, paraxylylenediamine having 8 carbon atoms, and 2,4-diaminotoluene having 8 carbon atoms.

Further, examples of the triamine in the cyclic amide compound and the non-cyclic amide compound include triaminocyclohexane having 6 carbon atoms and trimer triamine having 54 carbon atoms.

Examples of the monoamine in the acyclic amide compound include ammonia having 0 carbon atoms, ethylamine having 2 carbon atoms, hexylamine having 6 carbon atoms, octylamine having 8 carbon atoms, and stearylamine having 18 carbon atoms.

Examples of the [1 + 1] type acyclic amide compound obtained by condensing a monocarboxylic acid and a monoamine include stearic acid amide (molecular weight 283.49) and p-toluamide (molecular weight 135.17). Further, examples of the [1 + 1] type acyclic amide compound obtained by condensing monocarboxylic acid and diamine include ethylenediamine monostearic acid amide (molecular weight 326.56).

Examples of the [2 + 1] type acyclic amide compound obtained by condensing a monocarboxylic acid and a diamine include ethylenediamine bisstearic acid amide (molecular weight 593.02), ethylenediamine bispalmitic acid amide (molecular weight 536.9), and m-xylylenediamine bisstearate. Acid amide (molecular weight 669.11) and the like can be mentioned.

Examples of the [1 + 2] type acyclic amide compound obtained by condensing a dicarboxylic acid and a monoamine include succinate bisstearylamide (molecular weight 621.07), adipic acid bisstearylamide (molecular weight 649.12), and sebacic acid bisstearylamide (molecular weight). 705.27) and the like.

The acyclic amide compound can be substituted by ring-opening polymerization of lactam, and examples thereof include 6-nylon obtained by ring-opening polymerization of ε-caprolactam and 12-nylon obtained by ring-opening polymerization of lauryl lactam.

The flux of the present embodiment contains the above-mentioned cyclic amide compound as a thixo agent in an amount of 0.1 wt% or more and 8.0 wt% or less, more preferably 0.1 wt% or more and 1.5 wt% or less in an acyclic amide compound. The compound is 0.5 wt% or more and 8.0 wt% or less, more preferably 0.5 wt% or more and 4.0 wt% or less of the acyclic amide compound, and the total of the cyclic amide compound and the acyclic amide compound is 1.5 wt%. % Or more and 10.0 wt% or less.

If the amount of the cyclic amide compound is less than 0.1 wt%, the thixotropic property deteriorates. In addition, printing sagging and heating sagging cannot be suppressed. On the other hand, when the amount of the cyclic amide compound is more than 8.0 wt%, the total amount of the amide thixotropy increases, so that precipitation occurs in the flux and the printability deteriorates.

The flux of the present embodiment preferably contains an ester compound as a thixotropy, and contains 0 wt% or more and 8.0 wt% or less of the ester compound, and more preferably 0 wt% or more and 4.0 wt% or less of the ester compound.
Examples of the ester compound include hydrogenated castor oil and the like.

The flux of the present embodiment contains a compound represented by the following general formula (1) as a specific activator.

［式（１）中、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４は、それぞれ独立に、水素原子または炭素数１〜４のアルキル基を示す。］

[In formula (1), R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ]

In the general formula (1), R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a propyl group, a cyclopropyl group, a butyl group and a cyclobutyl group. Among them, R ¹ , R ² , R ³ and R ⁴ are preferably a hydrogen atom, a methyl group, an ethyl group and a cyclopropyl group, more preferably a hydrogen atom and a methyl group, and are hydrogen atoms. Is particularly preferable. R ¹ , R ² , R ³ and R ⁴ may be the same or different.

Examples of the compound represented by the general formula (1) include picolinic acid, 6-methylpicolinic acid, 6-ethylpicolinic acid, 3-cyclopropylpicolinic acid, 4-cyclopropylpicolinic acid, and 6-cyclopropylpicolinic acid. Examples thereof include 5-butylpicolinic acid and 6-cyclobutylpicolinic acid. Of these, picolinic acid is particularly preferred.
As the compound represented by the general formula (1), one type may be used alone, or two or more types may be mixed and used.

The flux of the present embodiment preferably contains 0.5 wt% or more and 7 wt% or less of the compound represented by the general formula (1), and more preferably 1.0 wt% of the compound represented by the general formula (1). Includes% or more and 5.0 wt% or less.

Examples of the rosin include raw material rosins such as gum rosin, wood rosin and tall oil rosin, and derivatives obtained from the raw material rosin. Examples of the derivative include purified rosin, hydrogenated rosin, disproportionated rosin, polymerized rosin, acid-modified rosin, phenol-modified rosin and α, β-unsaturated carboxylic acid-modified products (acrylicized rosin, maleated rosin, and fumarized products). (Rosin, etc.), and purified products, hydrides and disproportionated products of the polymerized rosin, and purified products, hydrides and disproportionated products of the α, β unsaturated carboxylic acid modified products, and one of them or Two or more types can be used.

The flux of the present embodiment preferably contains rosin in an amount of 30 wt% or more and 60 wt% or less, and more preferably contains rosin in an amount of 35 wt% or more and 60 wt% or less.

Examples of the solvent include water, alcohol solvents, glycol ether solvents, terpineols and the like. As alcohol-based solvents, isopropyl alcohol, 1,2-butanediol, isobornylcyclohexanol, 2,4-diethyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, 2,5 -Diol-2,5-hexanediol, 2,5-dimethyl-3-hexine-2,5-diol, 2,3-dimethyl-2,3-butanediol, 1,1,1-tris (hydroxymethyl) Ethan, 2-ethyl-2-hydroxymethyl-1,3-propanediol, 2,2'-oxybis (methylene) bis (2-ethyl-1,3-propanediol), 2,2-bis (hydroxymethyl) -1,3-propanediol, 1,2,6-trihydroxyhexane, bis [2,2,2-tris (hydroxymethyl) ethyl] ether, 1-ethynyl-1-cyclohexanol, 1,4-cyclohexanediol , 1,4-Cyclohexanedimethanol, erythritol, treitol, guayacol glycerol ether, 3,6-dimethyl-4-octin-3,6-diol, 2,4,7,9-tetramethyl-5-decine-4 , 7-diol and the like. Glycol ether-based solvents include hexyl diglycol, diethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether, 2-methylpentane-2,4-diol, diethylene glycol monohexyl ether, diethylene glycol dibutyl ether, and triethylene glycol monobutyl ether. , Tetraethylene glycol monomethyl ether and the like.

The flux of the present embodiment may further contain an organic acid (excluding the compound represented by the general formula (1)), an amine, and a halogen (organic halogen compound, amine hydrohalide). The flux of the present embodiment preferably contains 0 wt% or more and 10 wt% or less of the organic acid. The flux of the present embodiment preferably contains 0 wt% or more and 20 wt% or less of amine, and more preferably contains 0 wt% or more and 5 wt% or less of amine. The flux of the present embodiment preferably contains 0 wt% or more and 5 wt% or less of an organic halogen compound as a halogen, and preferably contains 0 wt% or more and 2 wt% or less of an amine hydrogen halide.

Organic acids (excluding compounds represented by the general formula (1)) include glutaric acid, adipic acid, azelaic acid, eicosandioic acid, citric acid, glycolic acid, succinic acid, salicylic acid, diglycolic acid, dipicolinic acid, Dibutylaniline diglycolic acid, suberic acid, sebacic acid, thioglycolic acid, terephthalic acid, dodecanedioic acid, parahydroxyphenylacetic acid, phenylsuccinic acid, phthalic acid, fumaric acid, maleic acid, malonic acid, lauric acid, benzoic acid, Tartrate acid, tris isocyanurate (2-carboxyethyl), glycine, 1,3-cyclohexanedicarboxylic acid, 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxymethyl) butanoic acid, 2,3- Dihydroxybenzoic acid, 2,4-diethylglutaric acid, 2-quinolinecarboxylic acid, 3-hydroxybenzoic acid, malic acid, p-anisic acid, stearic acid, 12-hydroxystearic acid, oleic acid, linoleic acid, linolenic acid, etc. Can be mentioned.

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

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

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

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

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

The flux of the present embodiment may further contain an antioxidant, and examples of the antioxidant include a hindered phenolic antioxidant and the like, preferably containing 0 wt% or more and 5 wt% or less of the antioxidant. .. The balance of the flux of the present embodiment is a solvent.

<Example of solder paste of this embodiment>
The solder paste of the present embodiment contains the above-mentioned flux and metal powder.
The metal powder is preferably a solder containing no Pb, and is a solder powder containing Sn alone, or Sn-Ag-based, Sn-Cu-based, Sn-Ag-Cu-based, Sn-Bi-based, and Sn-In. It is composed of a system or the like, or a powder of a solder alloy obtained by adding Sb, Bi, In, Cu, Zn, As, Ag, Cd, Fe, Ni, Co, Au, Ge, P and the like to these alloys.

The solder alloy has As: 25 mass ppm or more and 300 mass ppm or less, Sb: 0 mass ppm or more and 3000 mass ppm or less, Bi: 0 mass ppm or more and 10000 mass ppm or less, and Pb: 0 mass ppm or more and 5100 mass ppm or less. It is preferable to have an alloy composition in which at least one of them and the balance (Bal) are Sn. The solder alloy may further contain at least one of Ag: 0% by mass or more and 4% by mass or less and Cu: 0% by mass or more and 0.9% by mass or less.

As is an element capable of suppressing the change in viscosity of the solder paste with time. It is presumed that As has low reactivity with flux and is a noble element with respect to Sn, so that it can exert an effect of suppressing thickening. The lower limit of the As content is, for example, 25 mass ppm or more, preferably 50 mass ppm or more, and more preferably 100 mass ppm or more. On the other hand, if the amount of As is too large, the wettability of the solder alloy deteriorates. The upper limit of the As content is, for example, 300 mass ppm or less, preferably 250 mass ppm or less, and more preferably 200 mass ppm or less.

Sb is an element that has low reactivity with flux and exhibits an effect of suppressing thickening. When the solder alloy contains Sb, the lower limit of the Sb content is, for example, more than 0 mass ppm, preferably 25 mass ppm or more, more preferably 50 mass ppm or more, still more preferably 100 mass ppm or more. It is particularly preferably 300 mass ppm or more. On the other hand, if the Sb content is too large, the wettability of the solder alloy deteriorates, so it is necessary to set the content to an appropriate level. The upper limit of the Sb content is, for example, 3000 mass ppm or less, preferably 1150 mass ppm or less, and more preferably 500 mass ppm or less.

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

If at least one element of Sb, Bi and Pb is present, deterioration of the wettability of the solder alloy due to As can be suppressed. When the solder alloy contains Bi, the lower limit of the Bi content is, for example, more than 0 mass ppm, preferably 25 mass ppm or more, more preferably 50 mass ppm or more, still more preferably 75 mass ppm or more. It is particularly preferably 100 mass ppm or more, and most preferably 250 mass ppm or more. When the solder alloy contains Pb, the lower limit of the Pb content is, for example, more than 0 mass ppm, preferably 25 mass ppm or more, more preferably 50 mass ppm or more, still more preferably 75 mass ppm or more. It is 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 remarkably lowered, so that ΔT, which is the temperature difference between the liquidus temperature and the solidus temperature, becomes too wide. If ΔT is too wide, the liquid phase Bi and Pb will be concentrated because a high melting point crystal phase having a low content of Bi and Pb is precipitated in the solidification process of the molten solder. After that, when the temperature of the molten solder is further lowered, the low melting point crystal phase having a high concentration of Bi and Pb is segregated. Therefore, the mechanical strength and the like of the solder alloy are deteriorated, and the reliability is deteriorated. In particular, since the crystal phase having a high Bi concentration is hard and brittle, segregation in the solder alloy significantly lowers the reliability.

From this point of view, when the solder alloy contains Bi, the upper limit of the Bi content is, for example, 10000 mass ppm or less, preferably 1000 mass ppm or less, more preferably 600 mass ppm or less, and further. It is preferably 500 mass ppm or less. When the solder alloy contains Pb, the upper limit of the Pb content is, for example, 5100 mass ppm or less, preferably 5000 mass ppm or less, more preferably 1000 mass ppm or less, and further preferably 850 mass ppm or less. It is particularly preferably 500 mass ppm or less.

The solder alloy preferably satisfies the following mathematical formula (1).

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

As, Sb, Bi and Pb are all elements that have an effect of suppressing thickening. The total of these is preferably 275 mass ppm or more. In the formula (1), the As content is doubled because As has a higher effect of suppressing thickening than Sb, Bi, and Pb.

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

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

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

Further, the solder alloy preferably satisfies the following mathematical formula (2).

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

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

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

The denominator of the mathematical formula (2) is "Bi + Pb", and the mathematical formula (2) cannot be established unless these are included. Therefore, the solder alloy preferably contains at least one of Bi and Pb. As described above, the alloy composition containing no Bi and Pb is inferior in the wettability of the solder alloy.

The following mathematical formula (2a) is obtained by appropriately selecting the upper limit and the lower limit from the above preferred embodiments.

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

Ag is an optional element capable of forming Ag ₃ Sn at the crystal interface to improve the reliability of the solder alloy. In addition, Ag is an element whose ionization coefficient is noble with respect to Sn, and when it coexists with As, Pb and Bi, it promotes the effect of suppressing thickening of these elements. The Ag content is preferably 0% by mass or more and 4% by mass or less, more preferably 0.5% by mass or more and 3.5% by mass or less, and further preferably 1.0% by mass or more and 3.0% by mass or less. It is as follows.

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

The balance (Bal) of the solder alloy is preferably Sn. The solder alloy may contain unavoidable impurities in addition to the above-mentioned elements. Even if it contains unavoidable impurities, it does not affect the above-mentioned effects. If the content of In is too large, ΔT spreads, so if it is 1000 mass ppm or less, it does not affect the above-mentioned effect.

<Example of action and effect of flux and solder paste of this embodiment>
In a flux containing a thixo agent, a compound represented by the general formula (1), rosin, and a solvent, and the thixo agent contains a cyclic amide compound and an acyclic amide compound, the thixo agent is derived from the acyclic amide compound. As compared with the case of, the thixo property can be improved and the precipitation of the thixo agent can be suppressed without increasing the content of the acyclic amide compound. In addition, high solder wettability can be exhibited. In the solder paste using this flux, it is possible to obtain good printability in which bleeding, blurring and the like are suppressed, and it is possible to suppress printing sagging in which the solder paste flows after printing. Further, it is possible to prevent the solder paste from sagging due to heating during soldering.

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

The fluxes of Examples and Comparative Examples were prepared with the compositions shown in Table 1, Table 2, Table 3, Table 4, Table 5, Table 6, Table 7, and Table 8 below, and the solder paste was prepared using this flux. Then, the flux property, the ability to suppress the printing sagging of the solder paste, the printability, the ability to suppress the heating sagging, and the wetting rate were verified.
The composition ratios in Table 1, Table 2, Table 3, Table 4, Table 5, Table 6, Table 7, and Table 8 are wt (mass)% when the total amount of flux is 100.

The solder paste has a flux of 11 wt% and a metal powder of 89 wt%. The metal powder in the solder paste is a Sn-Ag-Cu based solder alloy in which Ag is 3.0 wt%, Cu is 0.5 wt%, and the balance is Sn, and the average particle size of the metal powder is φ20 μm. Is.

<Evaluation of thixotropy of flux>
(1) Verification method The evaluation of thixotropic property was carried out in accordance with JIS Z3284-3 4.2 using a spiral viscometer. The rotation speed of the viscometer was set to 3 rpm and 30 rpm, and the viscosity after rotation for a predetermined time was read to calculate the thixotropy.

(2) Judgment criteria 〇 〇: Thixotropy ratio is 0.60 or more 〇: Thixotropy ratio is 0.30 or more and less than 0.60 ×: Thixotropy ratio is less than 0.30

<Evaluation of solder paste's ability to suppress printing sagging>
(1) Verification method The evaluation of the printing sagging suppression ability of the solder paste conforms to JIS Z3284-3 4.3, and the solder is used on a copper plate using a stainless metal mask in which the solder paste printing portion is formed in a predetermined pattern. After printing the paste and removing the metal mask, store it at room temperature 25 ± 5 ° C. and relative humidity 50 ± 10% for 10 to 20 minutes, and among the printed patterns, not all the printed solder pastes are integrated. The minimum interval was visually confirmed. The thickness of the metal mask is 0.2 mm, the solder paste printing portion has a quadrangular opening, and the size is 3.0 × 1.5 mm. In the solder paste printing section, multiple openings of the same size are lined up at different intervals, and the opening interval L is 0.2-0.3-0.4-0.5-0.6-0.7-. It is 0.8-0.9-1.0-1.1-1.2 mm.

(2) Judgment criteria 〇: The minimum distance that does not become one after printing is 0.2 mm or less ×: The minimum distance that does not become one after printing exceeds 0.2 mm

<Evaluation of printability of solder paste>
(1) Verification method The printability of the solder paste is evaluated in accordance with JIS Z3284-3 4.1, and the solder paste is applied to the copper plate using a stainless metal mask in which the solder paste printing portion is formed in a predetermined pattern. After printing, it was visually confirmed that there was no bleeding or blurring at the initial stage of printing and during continuous printing.

(2) Judgment criteria 〇: No bleeding or blurring after printing ×: There is bleeding or blurring after printing

<Evaluation of the ability of solder paste to suppress heating sagging>
(1) Verification method The evaluation of the ability to suppress heating sagging of solder paste conforms to JIS Z3284-3 4.4, and the solder is used on a copper plate using a stainless metal mask in which a solder paste printing portion is formed in a predetermined pattern. After printing the paste and removing the metal mask, the paste was heated at 150 ± 10 ° C. for 10 minutes, and the minimum interval at which all the printed solder pastes were not integrated was visually confirmed among the printed patterns. The thickness of the metal mask is 0.2 mm, the solder paste printing portion has a quadrangular opening, and the size is 3.0 × 1.5 mm. In the solder paste printing section, multiple openings of the same size are lined up at different intervals, and the opening interval L is 0.2-0.3-0.4-0.5-0.6-0.7-. It is 0.8-0.9-1.0-1.1-1.2 mm.

(2) Judgment criteria 〇: Minimum distance not integrated is 1.0 mm or less ×: Minimum distance not integrated is more than 1.0 mm

<Evaluation of solder wettability (wetting speed)>
(1) Verification method The wetting rate of the solder paste conforms to the method of the meniscograph test, and a copper plate having a width of 5 mm, a length of 25 mm and a thickness of 0.5 mm is oxidized at 150 ° C. for 1 hour, and the copper oxide plate is a test plate. As a test device, Solder Checker SAT-5200 (manufactured by RHESCA) was used, and Sn-3Ag-0.5Cu (each numerical value was mass%) was used as a solder, and the evaluation was performed as follows.
First, the test plate was immersed 5 mm in each of the fluxes of Examples 1 to 47 and Comparative Examples 1 to 5 measured in a beaker, and the flux was applied to the test plate. Subsequently, after the flux was applied, the test plate to which the flux was applied was immediately immersed in the solder bath to obtain zero cross time (sec). Subsequently, the fluxes of Examples 1 to 47 and Comparative Examples 1 to 5 were measured 5 times, and the average value of the obtained 5 zero cross times (sec) was calculated. The test conditions were set as follows.
Immersion speed in solder bath: 5 mm / sec (JIS Z 3198-4)
Immersion depth in solder bath: 2 mm (JIS Z 3198-4)
Immersion time in solder bath: 10 sec (JIS Z 3198-4)
Solder tank temperature: 245 ° C (JIS C 60068-2-54)
The shorter the average value of the zero cross time (sec), the higher the wetting speed and the better the solder wetting property.

(2) Judgment criteria 〇: The average value of zero cross time (sec) is 6 seconds or less.
X: The average value of zero cross time (sec) exceeds 6 seconds.

<Comprehensive evaluation>
〇: Each evaluation of the thixotropic property of the flux, the printing sagging suppressing ability of the solder paste, the printing property of the solder paste, the heating sagging suppressing ability of the solder paste, and the wetting speed is 〇 or 〇〇.
X: At least one of each evaluation of the thixotropic property of the flux, the printing sagging suppressing ability of the solder paste, the printing property of the solder paste, the heating sagging suppressing ability of the solder paste, and the wetting rate is x.

In the present invention, as shown in Example 1, sebacic acid, which is a dicarboxylic acid having 10 carbon atoms, and 1,6-hexanediamine, which is a diamine having 6 carbon atoms, are polycondensed cyclically as a thixo agent. The present invention defines a cyclic amide compound in which a cyclic amide compound, sebacic acid, which is a dicarboxylic acid having 10 carbon atoms, and 1,6-hexanediamine, which is a diamine having 6 carbon atoms, are polycondensed in an acyclic manner. By including the amount within the specified range, the thiox property of the flux could be improved and the precipitation of the thiox agent could be suppressed. In addition, by adopting picolinic acid as a specific activator, the wetting speed was increased and the solder wetting property could be improved. Further, in the solder paste using this flux, good printability in which bleeding, blurring, etc. are suppressed can be obtained, and printing sagging in which the solder paste flows after printing can be suppressed. Furthermore, it was possible to suppress the heating sagging of the solder paste due to heating during soldering.

As in Example 2, even if picolinic acid is contained in an amount of 7 wt%, the thixotropy of the flux, the ability to impart a high wetting rate, the ability to suppress printing dripping of the solder paste, the printing property, and the ability to suppress heating dripping are not impaired. On the other hand, a sufficient effect was obtained. Further, as in Example 3, by containing 0.5 wt% of picolinic acid and using an organic acid in combination, the flux property, the ability to impart a high wetting rate, the ability to suppress printing sagging of solder paste, printability, and heating The ability to suppress sagging was not inhibited, and a sufficient effect was obtained for these.

As shown in Examples 4 to 6, picolinic acid is contained as a specific activator, and the flux can also be obtained by changing the type or amount of the cyclic amide compound and the acyclic amide compound within the range specified in the present invention. Sufficient effects were obtained on the thixo property, the wetting rate, the ability of the solder paste to suppress printing dripping, the printing property, and the ability to suppress heating dripping.

As shown in Examples 7 to 11, picolinic acid is contained as a specific activator, and the type of organic acid can be changed, a plurality of types of organic acids can be combined, or the amount of organic acid can be changed to change the amount of the organic acid. Sufficient effects were obtained on the wetting speed, the ability to suppress printing dripping of solder paste, printability, and the ability to suppress heating dripping.

As shown in Examples 12 to 15, even if a plurality of types of rosins containing picolinic acid as a specific activator and further changing the type of rosin are combined, the flux property, the wetting rate, and the printing sagging of the solder paste Sufficient effects were obtained on the inhibitory ability, printability, and heating sagging inhibitory ability.

As shown in Examples 16 to 17, picolinic acid is contained as a specific activator, and even if amine is contained, the flux property, wetting rate, ability to suppress printing sagging of solder paste, printability, and heating sagging A sufficient effect was obtained on the inhibitory ability.

As shown in Examples 18 to 19, picolinic acid is contained as a specific activator, and even if halogen is contained, the thixotropy of the flux, the wetting rate, the ability to suppress printing sagging of the solder paste, printability, and heating sagging A sufficient effect was obtained on the inhibitory ability.

As shown in Example 20, even if picolinic acid is contained as a specific activator and an antioxidant is also contained, the thixotropy of the flux, the wetting rate, the ability to suppress printing sagging of the solder paste, printability, and heating sagging A sufficient effect was obtained on the inhibitory ability.

As shown in Example 21, even if the amount of organic acid (excluding picolinic acid) is reduced by containing picolinic acid as a specific active agent and further using an amine, a halogen and an antioxidant in combination, the flux Sufficient effects were obtained on the picolinic acidity, wetting speed, printing sagging suppressing ability of solder paste, printability, and heating sagging suppressing ability.

As shown in Examples 22 to 23, picolinic acid is contained as a specific activator, and even by changing the amount of rosin, the flux property, the wetting rate, the ability to suppress printing sagging of solder paste, and the printability , A sufficient effect was obtained on the ability to suppress heating sagging.

As shown in Examples 24 to 28, the type of organic acid is changed by containing picolinic acid as a specific activator and further containing an ester compound as a thixo agent within the range specified in the present invention. By combining multiple types of organic acids and changing the amount of organic acids, sufficient effects can be obtained on the flux property, wetting rate, solder paste printing sagging ability, printability, and heating sagging suppressing ability. It was.

As shown in Examples 29 to 32, the type of rosin is changed by containing picolinic acid as a specific activator and further containing an ester compound as a thixotropy within the range specified in the present invention. Even by combining a plurality of types of rosins, sufficient effects were obtained on the thixotropy of the flux, the wetting rate, the ability to suppress printing dripping of the solder paste, the printing property, and the ability to suppress heating dripping.

As shown in Examples 33 to 34, picolinic acid is contained as a specific activator, and further, by containing an ester compound as a thixotropic agent within the range specified in the present invention, an amine can also be contained. Sufficient effects were obtained on the thixotropic property of the flux, the wetting rate, the printing sagging suppressing ability of the solder paste, the printing property, and the heating sagging suppressing ability.

As shown in Examples 35 to 36, picolinic acid may be contained as a specific activator, and an ester compound may be contained as a thixotropy within the range specified in the present invention, and halogen may also be contained. Sufficient effects were obtained on the thixotropy of the flux, the wetting rate, the ability to suppress printing dripping of the solder paste, the printing property, and the ability to suppress heating dripping.

As shown in Example 37, picolinic acid is contained as a specific active agent, and an ester compound is contained as a thixotropic agent within the range specified in the present invention, and further, within the range specified in the present invention. By containing the antioxidant, sufficient effects were obtained on the thixotropy of the flux, the wetting rate, the ability to suppress printing dripping of the solder paste, the printing property, and the ability to suppress heating dripping.

As shown in Example 38, it contains picolinic acid as a specific activator, further contains an ester compound as a thixo agent within the range specified in the present invention, and further contains an amine, a halogen, and an antioxidant. As a result, even if the amount of organic acids (excluding picolinic acid) is reduced, sufficient effects can be obtained on the tixo property of the flux, the wetting rate, the printing sagging ability of the solder paste, the printing property, and the heating sagging suppressing ability. It was.

As shown in Examples 39 to 40, picolinic acid is contained as a specific active agent, and an ester compound is contained as a thyxo agent within the range specified in the present invention, and further specified in the present invention. Even if the amount of rosin was changed within the above range, sufficient effects were obtained on the flux property, the wetting rate, the ability to suppress the printing dripping of the solder paste, the printing property, and the ability to suppress the heating dripping.

As shown in Example 41, by containing picolinic acid as the specific activator and further containing the ester compound as the thixotropy within the range specified in the present invention, even if the amount of the ester compound is reduced, the thixotropy of the flux Sufficient effects were obtained on the properties, wetting speed, printing sagging suppressing ability of solder paste, printability, and heating sagging suppressing ability.

As shown in Examples 42 to 44, picolinic acid is contained as a specific active agent within the range specified in the present invention, and further, an ester compound is contained as a thixo agent within the range specified in the present invention. As a result, by increasing the amount of the ester compound and reducing the acyclic amide compound, sufficient effects can be obtained on the nitrogen property of the flux, the wetting rate, the printing sagging ability of the solder paste, the printing property, and the heating sagging suppressing ability. Was printed.
Further, by heating at 1 ° C. / sec to 250 ° C. from 25 ° C. at N ₂ reflow, then ultrasonically cleaned in a beaker with a solvent, no flux residue Visual inspection revealed that those subsequently dried, washed Sex was obtained.

As shown in Example 45, picolinic acid is contained as a specific activator, the cyclic amide compound is contained in an amount of 0.1 wt% at the lower limit within the range specified in the present invention, and the acyclic amide compound is specified in the present invention. The total of the cyclic amide compound and the acyclic amide compound is within the range specified in the present invention, and the ester compound is contained as a thixo agent within the range specified in the present invention. Sufficient effects were obtained on the tixo property of the flux, the wetting rate, the ability to suppress printing dripping of the solder paste, the printing property, and the ability to suppress heating dripping.

As shown in Example 46, picolinic acid was contained as a specific activator, the cyclic amide compound was increased from the lower limit within the range specified in the present invention to include 0.3 wt%, and the acyclic amide compound was referred to as Example 45. The same 2.5 wt% is contained, and the total of the cyclic amide compound and the non-cyclic amide compound is within the range specified in the present invention, so that even if the content of the ester compound is reduced as compared with Example 45, the flux Sufficient effects were obtained on the thixo property, the wetting rate, the ability of the solder paste to suppress printing dripping, the printing property, and the ability to suppress heating dripping.

As in Example 47, picolinic acid is contained as a specific activator, the cyclic amide compound is contained in the same 0.3 wt% as in Example 46, and the acyclic amide compound is 8 wt at the upper limit within the range specified in the present invention. %, And even if the total of the cyclic amide compound and the non-cyclic amide compound is within the range specified in the present invention, the thiox property of the flux, the wetting rate, and the printing of the solder paste without containing the ester compound as the thiox agent. Sufficient effects were obtained on the ability to suppress sagging, printability, and the ability to suppress heating sagging.

On the other hand, as shown in Comparative Example 1, even if the cyclic amide compound is contained as the thixo agent and picolinic acid is contained as the specific active agent within the range specified in the present invention, the content of the acyclic amide compound is the present invention. When the total amount of the cyclic amide compound and the non-cyclic amide compound was outside the range specified in the present invention, an effect was obtained on the wetting rate, but the tixo property of the flux and the solder were obtained. No effect was obtained on the print sagging suppressing ability, printability, and heating sagging suppressing ability of the paste.

Further, as shown in Comparative Example 2, even if a cyclic amide compound and a non-cyclic amide compound are contained as a thixo agent and picolinic acid is contained as a specific active agent within the range specified in the present invention, the cyclic amide is contained. When the total of the compound and the acyclic amide compound was out of the range specified in the present invention, an effect was obtained on the wetting rate, but the taxi property of the flux, the ability to suppress printing sagging of the solder paste, and the printability. , No effect was obtained on the ability to suppress heating sagging.

Further, as shown in Comparative Example 3, if the cyclic amide compound is not contained as the thixotropy and picolinic acid is contained as the specific activator but the acyclic amide compound is contained outside the range specified in the present invention, the thixotropy of the flux is contained. The effect was obtained on the property, the wetting speed, the ability to suppress the printing sagging of the solder paste, and the ability to suppress the heating sagging, but no effect was obtained on the printability.

Further, as shown in Comparative Example 4, the cyclic amide compound and the acyclic amide compound are not contained as the thixo agent, and even if picolinic acid is contained as the specific activator, the ester compound is contained within the range specified in the present invention. Therefore, the effect was obtained on the tixo property of the flux, the wetting rate, the printing sagging suppressing ability of the solder paste, and the printing property, but not on the heating sagging suppressing ability.

Further, as shown in Comparative Example 5, even if both the cyclic amide compound and the non-cyclic amide compound are contained as the thixo agent, if picolinic acid is not contained as the specific activator, the flux is tyxous and the solder paste is printed. The effect was obtained on the sagging suppressing ability, the heating sagging suppressing ability, and the printability, but not on the wetting rate of the flux.

The thixo agent contains a cyclic amide compound and a non-cyclic amide compound using malonic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, cyclohexanedicarboxylic acid, phthalic acid, terephthalic acid and the like as dicarboxylic acids. In particular, sufficient effects were obtained on the pimelic acidity of the flux, the wetting rate, the ability to suppress printing dripping of solder paste, the printing property, and the ability to suppress heating dripping.

Further, even if the thixo agent contains a cyclic amide compound or a non-cyclic amide compound using cyclohexanetricarboxylic acid, benzenetricarboxylic acid or the like as the tricarboxylic acid, the flux property, wetting rate, ability to suppress printing sagging of solder paste, printing Sufficient effect was obtained on the sex and the ability to suppress heating sagging.

Further, as the thixo agent, ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, dimer diamine, phenylenediamine, m-xylylenediamine, paraxylylenediamine, 2,4-diaminotoluene and the like were used as diamines. Even when the cyclic amide compound and the non-cyclic amide compound were contained, sufficient effects were obtained on the thixo property of the flux, the wetting rate, the printing sagging suppressing ability of the solder paste, the printing property, and the heating sagging suppressing ability.

Further, even if the thixotropy contains a cyclic amide compound or a non-cyclic amide compound using triaminocyclohexane, trimertriamine, etc. as the triamine, the thixotropy of the flux, the wetting rate, the ability to suppress printing sagging of the solder paste, and the printability, A sufficient effect was obtained on the ability to suppress heating sagging.

Further, the thixo agent also contains an acyclic amide compound using acetic acid, palmitic acid, stearic acid, 12-hydroxystearic acid, behenic acid, montanic acid and the like as the monocarboxylic acid, so that the flux property and wetting rate can be increased. Sufficient effects were obtained on the printing sagging suppressing ability, printability, and heating sagging suppressing ability of the solder paste.

Further, even if the thixo agent contains an acyclic amide compound using ammonia, ethylamine, hexylamine, octylamine, stearylamine or the like as the monoamine, the flux property, wetting rate, ability to suppress printing sagging of solder paste, printing Sufficient effect was obtained on the sex and the ability to suppress heating sagging.

Further, even if the thixotropy contains a non-cyclic amide compound obtained by ring-opening polymerization of lactam, it has a sufficient effect on the thixotropic property of the flux, the wetting rate, the printing sagging ability of the solder paste, the printing property, and the heating sagging suppressing ability. was gotten.

<Evaluation of the thickening inhibitory effect of solder paste>
The effect of suppressing thickening of the solder paste prepared by using the flux of each of the above-mentioned examples and the solder alloy having the composition shown in Table 9 below was also verified.

(1) Verification method The obtained solder paste was rotated using a rotational viscometer (PCU-205, manufactured by Malcolm Co., Ltd.) according to the method described in "4.2 Viscosity Characteristics Test" of JIS Z 3284-3. The viscosity was continuously measured for 12 hours at a number: 10 rpm and a measurement temperature: 25 ° C. Then, the initial viscosity (viscosity after 30 minutes of stirring) and the viscosity after 12 hours were compared, and the thickening suppressing effect was evaluated based on the following criteria.

(2) Judgment criteria 〇: Viscosity after 13 hours ≤ Initial viscosity × 1.2: Viscosity increase over time is small and good ×: Viscosity after 13 hours> Initial viscosity × 1.2: Viscosity increase over time is large Bad

In the solder paste using the flux of each example shown in Tables 1 to 7 and the solder alloy of each Test Example A1 to A6 shown in Table 9 satisfying the above formulas (1) and (2), the solder paste In addition to the ability to suppress printing sagging, printability, the ability to suppress heating sagging, and the wetting speed, a sufficient effect was obtained for the effect of suppressing thickening.

On the other hand, a solder using the flux of each example shown in Tables 1 to 7 and the solder alloy of each Test Example B1 to B6 shown in Table 9 which does not satisfy the above formulas (1) and (2). In the paste, effects were obtained on the printing sagging suppressing ability, printability, heating sagging suppressing ability, and wetting speed of the solder paste, but no effect was obtained on the thickening suppressing effect.

From the above, it contains a thixo agent, a compound represented by the general formula (1), rosin, an organic acid and a solvent, and the thixo agent is cyclically composed of dicarboxylic acid and / or tricarboxylic acid and diamine and / or triamine. A non-cyclic amide compound in which a condensed cyclic amide compound and a monocarboxylic acid, a dicarboxylic acid and / or a tricarboxylic acid and a monoamine, a diamine and / or a triamine are acyclically polycondensed, or an acyclic amide compound obtained by ring-opening polymerization of lactam The cyclic amide compound is composed of dicarboxylic acid and tricarboxylic acid having 3 or more and 10 or less carbon atoms, diamine and triamine having 2 or more and 54 carbon atoms, and the acyclic amide compound is monocarboxylic acid, dicarboxylic acid and tricarboxylic acid. The carbon number of the acid is 2 or more and 28 or less, the carbon number of monoamine, diamine and triamine is 0 or more and 54 or less, the cyclic amide compound is 0.1 wt% or more and 8.0 wt% or less, and more preferably, the cyclic amide compound is 0. .1 wt% or more and 1.5 wt% or less, 0.5 wt% or more and 8.0 wt% or less of the acyclic amide compound, more preferably 0.5 wt% or more and 4.0 wt% or less of the acyclic amide compound, and cyclic In the flux according to the present invention in which the total of the amide compound and the acyclic amide compound is 1.5 wt% or more and 10.0 wt% or less, the acyclic amide compound is contained as compared with the case where the thixo agent is composed of the acyclic amide compound. It was possible to improve the thiox property without increasing the amount, suppress the precipitation of the thiox agent, and in addition, improve the wettability of the solder.

With the solder paste using this flux, it was possible to obtain good printability in which bleeding, blurring, etc. were suppressed, and it was possible to suppress printing sagging in which the solder paste flows after printing. Furthermore, it was possible to suppress the heating sagging of the solder paste due to heating during soldering.

Further, the flux according to the present invention contains 0 wt% or more and 8.0 wt% or less of the ester compound as a thixo agent, more preferably 0 wt% or more and 4.0 wt% or less of the ester compound; and 30 wt% or more and 60 wt% or less of the rosin. Preferably, rosin is 35 wt% or more and 60 wt% or less; organic acid is 0 wt% or more and 10 wt% or less; amine is 0 wt% or more and 20 wt% or less, more preferably amine is 0 wt% or more and 5 wt% or less; organic halogen compound is 0 wt% or less. 5 wt% or less, amine halide hydroxide 0 wt% or more and 2 wt% or less; antioxidant is contained in 0 wt% or more and 5 wt% or less, and the balance is a solvent. With such a composition, the thixotropic property of the flux due to the thixotropy containing the cyclic amide compound and the non-cyclic amide compound, the ability to suppress printing sagging of the solder paste, the printability, the ability to suppress heating sagging, and the general formula The wetting rate due to the inclusion of the compound represented by (1) was not inhibited, and a sufficient effect was obtained on these.

Further, this flux and As: 25 mass ppm or more and 300 mass ppm or less, Sb: 0 mass ppm or more and 3000 mass ppm or less, Bi: 0 mass ppm or more and 10000 mass ppm or less, and Pb: 0 mass ppm or more and 5100 mass ppm or less. At least one of the following, at least one of Ag: 0% by mass or more and 4% by mass or less, Cu: 0% by mass or more and 0.9% by mass or less, and the balance (Bal) of Sn. In addition, in the solder paste using the solder alloy satisfying the above formulas (1) and (2), the tyxo property of the flux and the suppression of printing sagging of the solder paste by containing the cyclic amide compound and the non-cyclic amide compound in the thixo agent. The ability, printability, ability to suppress heating sagging, and the wetting rate due to the inclusion of the compound represented by the general formula (1) were not inhibited, and a sufficient effect on the thickening suppressing effect was obtained.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a solder paste using a flux and a flux, which imparts chicivity, is excellent in printability, ability to suppress print sagging, and ability to suppress heat sagging, and has improved solder wettability. be able to.

Claims (17)

It contains a thixotropic agent, a compound represented by the following general formula (1), rosin, and a solvent.
The thixo agent contains a cyclic amide compound and an acyclic amide compound, and contains the cyclic amide compound in an amount of 0.1 wt% or more and 8.0 wt% or less, and the acyclic amide compound in an amount of 0.5 wt% or more and 8.0 wt% or less. Moreover, the total of the cyclic amide compound and the non-cyclic amide compound is 1.5 wt% or more and 10.0 wt% or less.
The cyclic amide compound is an amide compound having a molecular weight of 3000 or less in which a dicarboxylic acid and / or a tricarboxylic acid and a diamine and / or a triamine are cyclically polycondensed.
The acyclic amide compound is a flux characterized by being an amide compound in which a monocarboxylic acid, a dicarboxylic acid and / or a tricarboxylic acid and a monoamine, a diamine and / or a triamine are acyclically condensed.

[In formula (1), R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ] The flux according to claim 1, wherein the compound represented by the general formula (1) is picolinic acid. The flux according to claim 1 or 2, wherein the cyclic amide compound has 3 or more and 10 or less carbon atoms of the dicarboxylic acid and the tricarboxylic acid. The flux according to claim 1 or 2, wherein the cyclic amide compound has 6 or more and 10 or less carbon atoms of the dicarboxylic acid and the tricarboxylic acid. The flux according to claim 3 or 4, wherein the cyclic amide compound has 2 or more and 54 or less carbon atoms of diamine and triamine. The flux according to claim 3 or 4, wherein the cyclic amide compound has 6 carbon atoms of the diamine and the triamine. The cyclic amide compound is a amide compound in which a dicarboxylic acid having 3 or more and 10 or less carbon atoms and a diamine having 2 or more and 54 carbon atoms or less are cyclically polycondensed. 2. The flux according to 2. The cyclic amide compound according to claim 1 or 2, wherein the cyclic amide compound is an amide compound in which a dicarboxylic acid having 6 or more and 10 or less carbon atoms and a diamine having 6 carbon atoms are cyclically polycondensed. Flux. The cyclic amide compound has a dicarboxylic acid and a tricarboxylic acid having a carbon number of 3 or more and 10 or less, and a diamine and a triamine having a carbon number of 2 or more and 54 or less.
The acyclic amide compound is characterized in that the monocarboxylic acid, the dicarboxylic acid and the tricarboxylic acid have 2 or more and 28 or less carbon atoms, and the monoamine, diamine and triamine have 0 or more and 54 or less carbon atoms. The flux according to claim 2. The flux according to any one of claims 1 to 9, wherein the thixotropy further contains an ester compound. The flux according to claim 10, wherein the thixotropy contains hydrogenated castor oil as an ester compound. The thixotropy comprises 0.1 wt% or more and 1.5 wt% or less of the cyclic amide compound, and 0.5 wt% or more and 4.0 wt% or less of the non-cyclic amide compound. 2. The flux according to 2. The flux according to claim 10 or 11, wherein the thixotropy contains 0 wt% or more and 8.0 wt% or less of the ester compound. The flux according to any one of claims 1 to 13, characterized in that the compound represented by the general formula (1) is contained in an amount of 0.5 wt% or more and 7.0 wt% or less. The flux according to any one of claims 1 to 14, wherein the rosin is contained in an amount of 30 wt% or more and 60 wt% or less. Furthermore, amine is 0 wt% or more and 20 wt% or less,
Organic halogen compounds 0 wt% or more and 5 wt% or less,
The flux according to any one of claims 1 to 15, characterized in that it contains 0 wt% or more and 2 wt% or less of an amine hydrogen halide, or 0 wt% or more and 5 wt% or less of an antioxidant. A solder paste containing the flux according to any one of claims 1 to 16 and a metal powder.

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