阅读说明：本技术 助焊剂和焊膏 (Flux and solder paste ) 是由 行方一博 新井健文 早川真滋 于 2020-06-26 设计创作，主要内容包括：本发明的助焊剂为一种用于软钎焊的无卤素的助焊剂,所述助焊剂含有：包含利用差热分析所得的一个或多个吸热峰均在130～200℃的范围内被观察到的聚酰胺化合物的触变剂、和包含异氰脲酸衍生物的活性剂,前述异氰脲酸衍生物的含量相对于助焊剂整体为5.0质量％以下。(The soldering flux of the invention is halogen-free soldering flux for soldering, and the soldering flux contains: the flux contains a thixotropic agent comprising a polyamide compound in which one or more endothermic peaks obtained by differential thermal analysis are observed in the range of 130 to 200 ℃, and an active agent comprising an isocyanuric acid derivative, wherein the content of the isocyanuric acid derivative is 5.0% by mass or less with respect to the entire flux.)

1. A flux which is a halogen-free flux for soldering, comprising:

a thixotropic agent comprising a polyamide compound in which one or more endothermic peaks obtained by differential thermal analysis are observed in a range of 130 to 200 ℃, and

an active agent comprising an isocyanuric acid derivative,

the content of the isocyanuric acid derivative is 5.0 mass% or less with respect to the entire flux.

2. The flux according to claim 1, wherein a content of the isocyanuric acid derivative is 0.5% by mass or more and 5.0% by mass or less with respect to the entire flux.

3. The flux according to claim 1 or 2, wherein the isocyanuric acid derivative is at least one selected from bis (2-carboxyethyl) isocyanuric acid, tris (2-carboxyethyl) isocyanuric acid, and tris (2-carboxypropyl) isocyanuric acid.

4. The flux according to any one of claims 1 to 3, wherein the content of the polyamide compound is 1.0 mass% or more and 7.0 mass% or less with respect to the entire flux.

5. A solder paste comprising the flux of any one of claims 1 to 4 and a solder alloy.

Technical Field

The present invention relates to a flux used for soldering, and a solder paste containing the flux.

Background

In a mounting technique for mounting electronic components such as chip components and package boards on an electronic circuit board such as a printed circuit board, solder paste in which a solder alloy and a flux are mixed is used. Specifically, a solder paste is screen-printed on the pads on the surface of the electronic circuit board, and then the electronic component is mounted and heated (reflow soldering), thereby bonding the electronic component to the electronic circuit board.

In recent years, electronic components have been miniaturized along with miniaturization and high performance of electronic devices, and thus the pitch of pads on the surface of an electronic circuit board on which solder paste is printed tends to be narrowed. As a technique for improving the solder fusibility to such fine solder pads, for example, patent document 1 discloses a solder paste using a fatty acid ester of a sugar as a thixotropic agent contained in a flux. Further, patent document 2 discloses a solder paste using an aromatic carboxylic acid having a hydroxyl group or an acyl group at the ortho-position or the para-position as an activator contained in a flux.

Documents of the prior art

Patent document

Patent document 1: japanese unexamined patent application publication No. 2014-144473

Patent document 2: japanese laid-open patent publication No. 2017-64784

Disclosure of Invention

Problems to be solved by the invention

Conventionally, halogens are widely used as activators for improving the melting property of solder because they remove an oxide film on the surface of solder and reduce the surface tension of solder. In the solder pastes of patent documents 1 and 2, a halogen compound is also contained as an activator. However, halogen-free compounds have been developed in recent years because of the concern that harmful substances such as dioxin are generated during combustion. Therefore, there is a demand for the development of a solder paste which is halogen-free and exhibits excellent solder fusibility to a fine solder pad.

The present invention has been made in view of the above circumstances, and an object thereof is to provide: a halogen-free flux which exhibits excellent solder fusibility to a fine solder pad when used together with a solder alloy, and a solder paste containing the flux.

Means for solving the problems

The flux of the present invention is a halogen-free flux for soldering, which contains: the flux contains a thixotropic agent comprising a polyamide compound in which one or more endothermic peaks obtained by differential thermal analysis are observed in the range of 130 to 200 ℃, and an active agent comprising an isocyanuric acid derivative, wherein the content of the isocyanuric acid derivative is 5.0% by mass or less with respect to the entire flux.

In the flux of the present invention, the content of the isocyanuric acid derivative is preferably 0.5% by mass or more and 5.0% by mass or less with respect to the entire flux.

In the flux of the present invention, it is preferable that the isocyanuric acid derivative is at least one selected from the group consisting of bis (2-carboxyethyl) isocyanuric acid, tris (2-carboxyethyl) isocyanuric acid and tris (2-carboxypropyl) isocyanuric acid.

In the flux of the present invention, the content of the polyamide compound is preferably 1.0 mass% or more and 7.0 mass% or less with respect to the entire flux.

The solder paste of the present invention contains the above-described flux and a solder alloy.

Detailed Description

Hereinafter, a flux and a solder paste according to an embodiment of the present invention will be described.

< soldering flux >

(thixotropic agent)

The flux of the present embodiment includes, as a thixotropic agent, a polyamide compound in which one or more endothermic peaks obtained by differential thermal analysis are observed in a range of 130 to 200 ℃. The endothermic peak in the present specification means a peak having an endothermic amount of 10J/g or more. The endothermic peak is an index indicating a change in the state of the thixotropic agent. It is presumed that the state of the thixotropic agent changes from a solid to a liquid or glass state at a temperature at which an endothermic peak is observed. Therefore, it is considered that the endothermic peak of the polyamide compound as the thixotropic agent is observed in the range of 130 to 200 ℃, that is, the state of the thixotropic agent changes in this temperature range, and therefore the solder alloy is not inhibited from wet spreading.

The differential thermal analysis is carried out under the following conditions, for example, using a differential scanning calorimeter (Thermo plus DSC 8230, manufactured by Rigaku Corporation).

Measurement temperature range: 30 to 300 DEG C

Temperature rise rate: 10 ℃/min

And (3) measuring atmosphere: under nitrogen atmosphere, the flow rate is 30 mL/min

Sample amount: 10mg of

Examples of the polyamide compound include: aromatic polyamide compounds (semi-aromatic polyamide compounds or wholly aromatic polyamide compounds) having a cyclic compound such as a benzene ring or a naphthalene ring in the main chain, aliphatic polyamide compounds, and the like. Examples of the aromatic polyamide compound in which one or more endothermic peaks obtained by the differential thermal analysis are observed in the range of 130 to 200 ℃ include those known under the trade name of JH-180 (manufactured by Ito oil Co., Ltd.). The aliphatic polyamide compound having one or more endothermic peaks obtained by the differential thermal analysis, which are observed in the range of 130 to 200 ℃ is, for example, available under the trade names VA-79 (manufactured by Kyowa chemical Co., Ltd.), AMX-6096A (manufactured by Kyowa chemical Co., Ltd.), SP-10, SP-500 (manufactured by ay Industries, Inc., supra), Grilamid L20G, Grilamid TR55 (manufactured by EMS-CHEMIE (Japan) Ltd.). These polyamide compounds may be used in 1 kind or in combination of 2 or more kinds.

The content of the polyamide compound is preferably 1.0 mass% or more, and more preferably 3.0 mass% or more, based on the entire flux. The content of the polyamide compound is preferably 7.0 mass% or less, and more preferably 5.0 mass% or less, based on the entire flux. When the polyamide compound contains 2 or more species, the content is the total content of the polyamide compounds.

The flux of the present embodiment may contain a thixotropic agent other than the polyamide compound. The other thixotropic agent is not particularly limited, and examples thereof include bisamide compounds, hydrogenated castor oil, kaolin, colloidal silica, organobentonite, and glass frit. These may be used in 1 kind or 2 or more kinds in combination. The content of the other thixotropic agent is preferably 80% by mass or less, more preferably 40% by mass or less, based on the entire amount of the thixotropic agent, and further preferably no other thixotropic agent is contained.

(active agent)

The flux of the present embodiment contains an isocyanuric acid derivative as an active agent. The isocyanuric acid derivative in the present specification means a compound having an isocyanuric acid skeleton represented by the following general formula (1).

(in the formula, R¹、R²、R³The same or different, represent hydrogen atom, carboxyl, alkyl with 1-8 carbon atoms, and organic group represented by-Y-X (wherein, Y is alkylene, phenylene or cycloalkylene with 1-6 carbon atoms, and X is carboxyl, hydroxyl, amino, phenyl or organic group containing phosphorus atom). )

As the aforementioned isocyanuric acid derivative, it is preferably selected from bis (2-carboxyethyl) isocyanuric acid (i.e., R in the general formula (1))¹Is a hydrogen atom, R²、R³Is the same organic group represented by-Y-X, Y is an ethylene group, X is a carboxyl group, tris (2-carboxyethyl) isocyanuric acid (i.e., R in the general formula (1))¹、R²、R³Is the same organic group represented by-Y-X, Y is an ethylene group, X is a carboxyl group, and tris (2-carboxypropyl) isocyanuric acid (i.e., R in the general formula (1))¹、R²、R³Is at least one of the same organic groups represented by-Y-X, Y is a propylene group, and X is a carboxyl group).

The content of the isocyanuric acid derivative is 5.0% by mass or less, preferably 3.0% by mass or less, and more preferably 2.5% by mass or less, based on the entire flux. The content of the isocyanuric acid derivative is preferably 0.5% by mass or more, and more preferably 1.0% by mass or more, based on the entire flux. When the isocyanuric acid derivative contains 2 or more species, the content is the total content of the isocyanuric acid derivative.

The flux of the present embodiment may contain an active agent other than the isocyanuric acid derivative. The other active agent is not particularly limited, and examples thereof include organic acid-based active agents, amine compounds, amino acid compounds, and the like.

The organic acid-based active agent is not particularly limited, and examples thereof include monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, capric acid, lauric acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, tuberculostearic acid, arachidic acid, behenic acid, xylonic acid, and glycolic acid; dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, methylsuccinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, tartaric acid, and diglycolic acid; and other organic acids such as dimer acid, levulinic acid, lactic acid, acrylic acid, benzoic acid, salicylic acid, anisic acid, citric acid, and picolinic acid.

Examples of the amine compound include, but are not particularly limited to, tetraacetylethylenediamine (N, N' -tetraacetylethylenediamine), N-acetylimidazole, N-acetylphthalimide, acetamidobenzoic acid (3-acetamidobenzoic acid, 4-acetamidobenzoic acid), N-acetamidobenzoic acid, acetamidobenzoic acid (2-acetamide-6-nitrobenzoic acid, 3-acetamido4-nitrobenzoic acid, 3-acetamido2-nitrobenzoic acid, and 5-acetamido2-nitrobenzoic acid).

The amino acid compound is not particularly limited, and examples thereof include N-acetylphenylalanine (N-acetyl-L-phenylalanine, N-acetyl-DL-phenylalanine, N-acetyl-D-phenylalanine), N-acetylglutamic acid (N-acetyl-L-glutamic acid), N-acetylglycine, N-acetylleucine (N-acetyl-L-leucine, N-acetyl-DL-leucine, N-acetyl-D-leucine), and N-acetylphenylglycine (N-acetyl-N-phenylglycine, N-acetyl-L-phenylglycine, N-acetyl-DL-phenylglycine).

The other active agents may be used in combination of 1 or 2 or more. The content of the other active agent is preferably 15 mass% or less, and more preferably 10 mass% or less, with respect to the entire flux.

The flux of the present embodiment is halogen-free from the viewpoint of environmental load. In the present specification, halogen-free means that the contents of halogen elements (F: fluorine, Cl: chlorine, Br: bromine, I: iodine) are 1000ppm or less (JEITA ET-7304A). The flux of the present embodiment may contain a halogen-based activator such as an amine halogen salt or a halogen compound if the flux satisfies the halogen-free condition. Examples of the amine halide salt include diethylamine, dibutylamine, tributylamine, diphenylguanidine, and cyclohexylamine. Examples of the halogen of the amine halide salt include fluorine, chlorine, bromine, and iodine. Examples of the halogen compound include tris (2, 3-dibromopropyl) isocyanurate, 2, 3-dibromo-2-butene-1, 4-diol, 2-bromo-3-iodo-2-butene-1, 4-diol, and TBA-bis (2, 3-dibromopropyl ether).

(solvent)

The flux of the present embodiment may contain a solvent. The solvent is not particularly limited, and a known solvent can be used. Examples of the solvent include: glycol ethers such as diethylene glycol monohexyl ether (hexyl diol), diethylene glycol dibutyl ether (butyl diol), diethylene glycol mono 2-ethylhexyl ether (2-ethylhexyl diol), diethylene glycol monobutyl ether (butyl diol), and triethylene glycol monobutyl ether (butyl triol); aliphatic compounds such as n-hexane, isohexane and n-heptane; esters such as isopropyl acetate, methyl propionate, and ethyl propionate; ketones such as methyl ethyl ketone, methyl n-propyl ketone, and diethyl ketone; alcohols such as ethanol, n-propanol, isopropanol, and isobutanol. The solvent may be used in 1 kind or in combination of 2 or more kinds.

The content of the solvent is not particularly limited, and is, for example, preferably 10.0 mass% or more, and more preferably 20.0 mass% or more, with respect to the entire flux. The content of the solvent is preferably 60.0 mass% or less, and more preferably 45.0 mass% or less, based on the entire flux. When the solvent includes 2 or more kinds, the content is the total content of the solvents.

(resin)

The flux of the present embodiment may contain a resin. Examples of the resin include rosin-based resins and synthetic resins. The rosin-based resin is not particularly limited, and for example, 1 or more kinds of rosin-based resins selected from rosins and rosin derivatives (for example, hydrogenated rosins, polymerized rosins, disproportionated rosins, acrylic-modified rosins, and the like) can be used. The synthetic resin is not particularly limited, and a known synthetic resin such as a terpene-phenol resin can be used. The resin may be used in 1 kind or in combination of 2 or more kinds.

The content of the resin is preferably 30% by mass or more, and more preferably 40% by mass or more, based on the entire flux. The content of the resin is preferably 70% by mass or less, and more preferably 50% by mass or less, based on the entire flux. When the resin includes 2 or more species, the content is the total content of the resin.

The flux of the present embodiment may contain, for example, at least 1 selected from a stabilizer, a surfactant, an antifoaming agent, and an anticorrosive agent as other additives. The total content of the other additives is not particularly limited, and may be, for example, 5.0 mass% or less with respect to the entire flux.

The flux of the present embodiment is a halogen-free flux for soldering, which contains: the flux contains a thixotropic agent comprising a polyamide compound in which one or more endothermic peaks obtained by differential thermal analysis are observed in the range of 130 to 200 ℃, and an active agent comprising an isocyanuric acid derivative, wherein the content of the isocyanuric acid derivative is 5.0% by mass or less with respect to the entire flux. According to the above aspect, when the flux is used together with a solder alloy, the flux exhibits excellent solder fusibility to a fine land.

In the flux of the present embodiment, the content of the isocyanuric acid derivative is preferably 0.5% by mass or more and 5.0% by mass or less with respect to the entire flux. According to the above aspect, when the flux is used together with a solder alloy, the solder fusibility to a fine land is improved.

In the flux of the present embodiment, the isocyanuric acid derivative is preferably at least 1 selected from bis (2-carboxyethyl) isocyanuric acid, tris (2-carboxyethyl) isocyanuric acid, and tris (2-carboxypropyl) isocyanuric acid. According to the above aspect, when the flux is used together with a solder alloy, the solder fusibility to a fine land is improved.

In the flux of the present embodiment, the content of the polyamide compound is preferably 1.0 mass% or more and 7.0 mass% or less with respect to the entire flux. According to the above aspect, when the flux is used together with a solder alloy, the solder fusibility to a fine land is improved.

The flux of the present embodiment can be obtained by: for example, a thixotropic agent, an active agent, and a solvent, a resin, and other additives as needed are put into a heating container, and then heated to 160 to 180 ℃ to dissolve all the raw materials, and finally cooled to room temperature.

The flux of the present embodiment includes a thixotropic agent, an active agent, a solvent, a resin, and other additives, but is not limited to this embodiment. Other embodiments of the flux include thixotropic agents, active agents, solvents, resins, and other additives.

< solder paste >

The solder paste of the present embodiment contains the above-described flux and a solder alloy. More specifically, the solder paste can be obtained by mixing a solder alloy powder and the flux. The content of the flux is preferably 5 to 20 mass% with respect to the entire solder paste. The content of the solder alloy powder is preferably 80 to 95 mass% with respect to the entire solder paste.

The powder size of the solder alloy is not particularly limited, but is preferably 4 or more, that is, 50 μm or less, and more preferably 6 or more, that is, 25 μm or less, as defined in JIS Z3284-1, in order to improve printability to a fine pattern.

Examples of the solder alloy include a lead-free solder alloy and a lead-containing eutectic solder alloy, but the lead-free solder alloy is preferable from the viewpoint of reducing the environmental load. Examples of the lead-free solder alloy include alloys containing tin, silver, copper, indium, zinc, bismuth, antimony, and the like. In particular, the solder alloy is preferably a medium-temperature-system, medium-high-temperature-system, and high-temperature-system lead-free solder alloy specified in JIS Z3282: 2017(ISO9453) from the viewpoint of improving solder fusibility to a fine solder pad. Specific examples of such alloys include Sn/Ag, Sn/Ag/Cu, Sn/Ag/Bi, Sn/Ag/Cu/Bi, Sn/Sb, Sn/Ag/Bi/In, and Sn/Ag/Cu/Bi/In/Sb alloys.

The solder paste of the present embodiment contains the above-described flux and solder alloy, and thus exhibits excellent solder fusibility to a fine land.

Examples

The present invention will be described below with reference to examples, but the present invention is not limited to the following examples.

< preparation of solder paste >

The resin, thixotropic agent and solvent were charged in the compounding amounts shown in table 1 into a heating vessel and heated to 180 ℃. Thereafter, the varnish component and other components are mixed at room temperature, thereby obtaining a uniformly dispersed flux. The respective amounts shown in table 1 were equal to the contents of the respective components contained in the flux. Next, the respective fluxes were mixed so that they became 13.0 mass% and the solder powders (Sn-3.0 wt% Ag-0.5 wt% Cu, size: 10-25 μm) became 87.0 mass%, to obtain solder pastes of examples and comparative examples.

[ Table 1]

The details of each raw material shown in table 1 are shown below.

KE-604: acrylic acid modified rosin manufactured by Mitsuwa chemical industries Ltd

S-145: terpene phenol resin, YASUHARA chemcal co

JH-180: semi-aromatic polyamide compound, product of itai-kamura co

VA-79 aliphatic Polyamide Compound, product of Kyoeisha chemical Co., Ltd

AMX-6096A aliphatic polyamide compound manufactured by Kyoeisha chemical Co., Ltd

WH-255 aliphatic polyamide compound, manufactured by Kyoeisha chemical Co., Ltd

BTG (BTG): triethylene glycol monobutyl ether manufactured by Nippon emulsifier Co Ltd

HeDG: diethylene glycol monohexyl ether manufactured by Nippon emulsifiers Ltd

Adipic acid: manufactured by Tokyo chemical industry Co Ltd

Sebacic acid: manufactured by Tokyo chemical industry Co Ltd

Methyl succinic acid: manufactured by Tokyo chemical industry Co Ltd

Succinic acid: manufactured by Tokyo chemical industry Co Ltd

Bis (2-carboxyethyl) isocyanuric acid: manufactured by Tokyo chemical industry Co Ltd

Tris (2-carboxyethyl) isocyanuric acid: manufactured by Tokyo chemical industry Co Ltd

Tris (2-carboxypropyl) isocyanuric acid: manufactured by Tokyo chemical industry Co Ltd

N-acetyl-L-glutamic acid: manufactured by Tokyo chemical industry Co Ltd

2, 2' -methylenebis (6-tert-butyl-4-methylphenol): manufactured by Tokyo chemical industry Co Ltd

< measurement of endothermic Peak temperature >

The endothermic peak temperature of each thixotropic agent was determined by differential thermal analysis. Specifically, the reaction was carried out under the following conditions using a differential scanning calorimeter (Thermo plus DSC 8230, manufactured by Rigaku Corporation). Table 2 shows the endothermic peak temperatures obtained by the differential thermal analysis, at which the endothermic amount is 10J/g or more.

Measurement temperature range: 30 to 300 DEG C

Temperature rise rate: 10 ℃/min

And (3) measuring atmosphere: under nitrogen atmosphere, the flow rate is 30 mL/min

Sample amount: 10mg of

[ Table 2]

From the results shown in Table 2, it is understood that JH-180 is a polyamide compound in which 1 endothermic peak obtained by differential thermal analysis is observed in the range of 130 to 200 ℃. Further, VA-79 and AMX-6096A are polyamide compounds in which 3 endothermic peaks obtained by differential thermal analysis are observed in the range of 130 to 200 ℃. JH-180, VA-79 and AMX-6096A are therefore thixotropic agents which meet the requirements of the invention. WH-255 is a polyamide compound in which 2 endothermic peaks out of 3 endothermic peaks obtained by differential thermal analysis are observed in the range of 130 to 200 ℃. Therefore, WH-255 is a thixotropic agent that does not satisfy the requirements of the present invention.

< evaluation of melting Property of solder >

The solder pastes of the examples and comparative examples were applied to copper pads (square shape of 0.2mm × 0.2 mm) on the surface of a substrate having a size of 100mm × 100mm and a thickness of 1.6mm at a thickness of 80 μm. Subsequently, the solder was heated under the following temperature conditions to melt the solder. The heating is performed in the order of (i) → (ii).

< temperature Condition >

(i) During preheating

Temperature rise rate: 1.0-3.0 ℃/sec

Preheating temperature: 150-190 ℃/60-100 seconds

Heating the environment: atmosphere of air

(ii) When the solder is melted

Temperature rise rate: 1.0-2.0 ℃/sec

Melting temperature: 219 ℃ or higher and 30 seconds or longer

Peak temperature: 230 to 250 DEG C

The solder fusibility was evaluated visually based on the following criteria. The ratio of the number of pads corresponding to each reference to the total number of pads (50 pads) is shown in table 1.

O: soft solder has melted (lustrous)

And (delta): with a portion of solder particles

X: soft solder not melted (dull)

From the results in table 1, it is understood that the solder pastes of the respective examples satisfying all the requirements of the present invention exhibit excellent solder fusibility to fine solder pads since the number of solder pads on which solder has been melted is 60% or more.

On the other hand, it is found that the solder pastes of comparative examples 1 and 2, which do not contain isocyanuric acid derivative as an active agent, have solder-melted lands less than 60%, and are in a state where some solder particles remain in most of the lands, and therefore, solder-melting properties with respect to fine lands are deteriorated. In addition, it is understood that the solder paste of comparative example 3, which contains a polyamide compound as a thixotropic agent, the endothermic peak of which is observed in a range of 130 to 200 ℃ by differential thermal analysis, is poor in solder fusibility to fine pads because the solder is not melted in most of the pads. In addition, the solder paste of comparative example 4 in which the content of the isocyanuric acid derivative was more than 5.0 mass% with respect to the entire flux was in a state in which some solder particles remained in most of the lands, and thus it was found that the solder fusibility to the fine lands was deteriorated.