JP2011224652A - Flux for solder and solder composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solder composition which is good in solderability, excels in color tone of a flux residue, and reduces the flux residue, and a flux which can provide such solder composition.SOLUTION: The flux for solder is characterized in that the maximum absorbance A in a region 254 nm or more measured by an ultraviolet ray absorptiometric method (measuring condition: sample concentration 1 g/dm, 1 cm of cell length) is 0.15 or less, and that it contains rosins (A) of which the content of a component with molecular weight of 320 measured by a gas chromatograph mass spectrometry of methylation treatment is 95% or more of the amount of sum total of the component with molecular weight of 314-320.

Description

The present invention relates to a solder flux and a solder composition.

Rosin is widely used in solder flux because it has an action to remove the oxide film on the surface of the solder powder (cleaning action) and an action to prevent reoxidation of the solder powder (base resin action) ( For example, see Patent Document 1).

However, rosins usually contain an abietan-based resin acid having a conjugated double bond in the molecule (such as abietic acid, levopimaric acid, parastrinic acid, or neoabietic acid). Abietan-based resin acids are very easily oxidized, and thus have a problem of poor thermal stability such as discoloration and quality deterioration.

Therefore, it has been proposed to use a rosin hydride (hydrogenated rosin), a disproportionate (disproportionated rosin) or the like for the purpose of stabilizing rosins (see, for example, Patent Document 2). When hydrogenated rosin or disproportionated rosin is used, discoloration and quality deterioration can be improved to some extent, but further improvement has been demanded. The applicant has proposed a solder flux containing a hydrogenated polymerized rosin with a good color tone of the residue after reflow (see Patent Document 3). However, a solder flux with a better color tone of the flux residue is required. It was.

JP-A-9-10988 JP 2002-144077 A JP 2009-285715 A

An object of the present invention is to provide a solder composition having good solderability, excellent color tone of a flux residue, inconspicuous residue, and reducing the flux residue, and a flux capable of providing such a solder composition. And

As a result of intensive studies, the present inventor has found that the above-described problems can be solved by using rosins containing specific components, and completed the present invention.

That is, according to the present invention, the maximum absorbance A (measurement conditions: sample concentration 1 g / dm ³ , cell length 1 cm) in the region of 254 nm or more by ultraviolet absorption spectrophotometry is 0.15 or less, and the gas chromatograph of methylated products Solder flux containing rosin (A) whose molecular weight 320 component measured by mass spectrometry is 95% or more of the total amount of components having a molecular weight of 314 to 320; powder solder and solder flux The present invention relates to a solder composition.

ADVANTAGE OF THE INVENTION According to this invention, the soldering flux which is favorable for solderability, is excellent in the color tone of a flux residue, a residue is not conspicuous, and reduces a flux residue can be provided. Moreover, the solder flux of the present invention can provide a solder composition having excellent heat resistance and good color tone.

The solder flux of the present invention has a maximum absorbance A (measurement condition: sample concentration of 1 g / dm ³ , cell length of 1 cm) in the region of 254 nm or more by ultraviolet absorption photometry, which is 0.15 or less. Containing rosins (A) (hereinafter referred to as component (A)) in which the content of components having a molecular weight of 320 measured by gas chromatography mass spectrometry is 95% or more of the total amount of components having a molecular weight of 314 to 320 Features.

When the maximum absorbance A (measurement condition: sample concentration 1 g / dm ³ , cell length 1 cm) in the region of 254 nm or more by ultraviolet absorption spectrophotometry of the component (A) exceeds 0.15, or a gas chromatograph of methylated products When the content of a component having a molecular weight of 320 measured by mass spectrometry is less than 95% of the total amount of components having a molecular weight of 314 to 320, a highly reactive conjugated double bond or various impurities are contained in the molecule. For this reason, the heat stability during soldering in the case of a solder composition is deteriorated. In the component (A), the absorbance in the region of 254 nm or more by the ultraviolet spectrophotometry is mainly a peak related to the carbon-carbon unsaturated bond, and the increase in the value means that there are many unsaturated bonds in the molecule. It means to become. In addition, if there are many coloring impurities, the value is considered to increase. Since the carbon-carbon unsaturated bond is rich in reactivity, it easily reacts with oxygen and various components in the solder composition, causing coloration and leading to generation of unnecessary compounds. In addition, the component having a molecular weight of 320 of the methylated product means that the carboxyl group of the resin acid component of component (A) is methylated to form a carboxylic acid ester, and the carbon-carbon unsaturated bond in the molecule is present. All correspond to hydrogenated ones. The component having a molecular weight of 314 corresponds to a component having three carbon-carbon unsaturated bonds in the molecule. Therefore, the content of the component having the molecular weight of 320 is 95% or more of the total amount of the components having the molecular weight of 314 to 320, which means that the component having the carbon-carbon unsaturated bond contained in the component (A) is extremely small. Means that.

Component (A) is usually a hydrogenation of natural rosins such as wood rosin, tall oil rosin, gum rosin and rosin derivatives (a) (hereinafter referred to as component (a)) such as disproportionated rosin and hydrogenated rosin. The content of the component having a molecular weight of 320 measured by gas chromatography mass spectrometry of methylated products such as tetrahydroabietic acid and tetrahydropimalic acid is 95% or more of the total amount of the components including the components having a molecular weight of 314 to 320. It is obtained by doing so. The component (a) is preferable because it can be refined to improve the color tone and reduce impurities. Although it does not specifically limit as a purification method, Specifically, distillation, recrystallization, extraction etc. are mentioned, for example. In the case of distillation, for example, the unpurified component (a) is usually performed under distillation conditions of a temperature of about 200 to 300 ° C. and a pressure of about 130 to 1300 Pa. The distillation time may be determined according to the distillation conditions. In the case of recrystallization, for example, the unpurified component (a) is dissolved in a good solvent, and then the solvent is distilled off to make a concentrated solution, and a poor solvent is added to this solution. Examples of the good solvent include benzene, toluene, xylene, chloroform, lower alcohols having 1 to 3 carbon atoms, ketones such as acetone, and acetates such as ethyl acetate. Examples of the poor solvent include n-hexane, n-heptane, cyclohexane, isooctane and the like. Further, in the above purification, the unpurified component (a) may be made into an alkaline aqueous solution using alkaline water, and the insoluble unsaponified product produced may be extracted with an organic solvent, and then the aqueous layer may be neutralized.

Hydrogenation of a component (a) can be performed by a well-known method. Specifically, for example, in the presence of a hydrogenation catalyst, the component (a) is usually added at about 1 to 25 MPa, preferably about 5 to 20 MPa under hydrogen pressure for about 0.5 to 7 hours, preferably 1 to 5 hours. This is done by heating. Examples of hydrogenation catalysts include palladium, rhodium, ruthenium, platinum and nickel metals supported on alumina, silica, diatomaceous earth, carbon, titania and other supported metals, nickel, platinum and other metal powders, iodine and iron iodide. Various known materials such as iodides can be used. Among these, palladium, rhodium, ruthenium or platinum-based catalysts are preferable in terms of hydrogenation efficiency (good hydrogenation rate and short hydrogenation time). The amount of the catalyst used is usually about 0.01 to 10 parts by weight, preferably 0.01 to 5 parts by weight, per 100 parts by weight of component (a). The hydrogenation temperature is about 100 to 300 ° C, preferably 150 to 290 ° C. Moreover, you may perform hydrogenation in the state which melt | dissolved rosin in the solvent as needed. The solvent to be used is not particularly limited, but a solvent that is inert to the reaction and easily dissolves the raw materials and products is preferable. For example, cyclohexane, n-hexane, n-heptane, decalin, tetrahydrofuran, dioxane and the like can be used alone or in combination of two or more. Although the usage-amount of a solvent is not restrict | limited in particular, Usually, it uses so that solid content may be about 10 weight% or more with respect to raw material resin. Preferably it is the range of 10 to 70 weight%. In the case of hydrogenated rosin hydrogenated under general hydrogenation conditions, the content of the component having a molecular weight of 320 measured by gas chromatography mass spectrometry of the methylated product is the sum of the components having a molecular weight of 314 to 320. It only increases to about 20% by weight of the amount. Therefore, in order to obtain the component (A), the hydrogenation conditions are severely repeated such as repeating the hydrogenation of the component (a), increasing the amount of catalyst used, increasing the hydrogenation temperature, increasing the hydrogen pressure, extending the reaction time, etc. It is necessary to select the catalyst type.

The softening point (ring ball method) of the component (A) thus obtained is not particularly limited, but it is usually preferably about 60 ° C. or higher. The component (A) having a softening point of less than 60 ° C. has increased low-molecular components due to decarboxylation and the like, leading to a decrease in activity associated with a decrease in acid value. Although the acid value of a component (A) is not specifically limited, Usually, it is preferable to set it as about 150 mgKOH / g or more. In the component (A) having an acid value of less than 150 mgKOH / g, low molecular components due to decarboxylation and the like are increasing, leading to a decrease in activity associated with a decrease in acid value. It is preferable to make the color tone of the component (A) colorless and transparent of 300 Hazen (JIS K 0071-1) or less because the color tone of the flux residue becomes good. In addition, it is preferable to use component (A) as a rosin derivative having a 99% weight loss temperature of 500 ° C. or less in thermogravimetry at a rate of temperature increase of 5 ° C./min.

The solder flux of the present invention can be used as a flux such as post flux used for flow soldering, flux such as cream solder used for reflow soldering, and solder containing solder used for manual soldering.

The solder flux of the present invention is characterized by containing the component (A), and further, a flux base resin other than the known component (A), a thixotropic agent, an activator, and other additives. Etc. may be contained.

As a flux base resin, if it is different from a component (A), it will not specifically limit and a well-known thing can be used. Specific examples include gum rosin, polymerized rosin, hydrogenated rosin, disproportionated rosin, various other rosin derivatives, and synthetic resins such as polyester resin, phenoxy resin, terpene resin, and polyamide resin.

The solvent is not particularly limited, and known solvents can be used. Specifically, alcohols such as ethanol, n-propanol, isopropanol and isobutanol, glycol ethers such as butyl carbitol and hexyl carbitol, esters such as isopropyl acetate, ethyl propionate, butyl benzoate and diethyl adipate And hydrocarbons such as n-hexane, dodecane, and tetradecene.

The thixotropic agent is not particularly limited, and known ones can be used. Specifically, for example, hardened castor oil, beeswax, carnauba wax, stearamide, hydroxystearic acid ethylene bisamide and the like can be used.

As an activator, it does not specifically limit but a well-known thing can be used. Specific examples include amine hydrohalides, organic acids, and organic amines.

As an additive, if it can be normally used for preparation of a flux, it will not specifically limit, A well-known thing can be used. Additives such as antioxidants, antifungal agents and matting agents can be contained.

The solder composition of the present invention contains solder powder and the above solder flux.

The alloy composition of the solder powder used in the present invention is not particularly limited, and various known ones can be used. For example, the alloy composition of the solder powder includes conventionally known tin-lead alloys, tin-silver alloys and tin-zinc alloys that have been developed as lead-free solders; and the above solder alloys include copper, bismuth, What added indium, antimony, etc. can be used. Although the usage-amount of each component of cream solder is not specifically limited, Usually, the solder flux is about 5 to 20 parts by weight with respect to about 80 to 95 parts by weight of the solder powder.

In addition to the solder powder and the solder flux, a known additive such as a solvent usually used for preparing the solder composition may be used for the solder composition of the present invention.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the examples, “%” and “part” mean “% by weight” and “part by weight” unless otherwise specified.

Production Example 1
600 g of Chinese hydrogenated rosin (manufactured by Guangxi Zhengzhou Nislin Industrial Chemical Co., Ltd.) was charged into a 1 liter flask and distilled under reduced pressure of 400 Pa to obtain a component distilled at 195 to 250 ° C. 200 g of a component distilled at 195 to 250 ° C., 3.0 g of 5% palladium alumina, and 200 g of cyclohexane were charged into a 1 liter autoclave, the inside of the system was sufficiently replaced with hydrogen gas, and the initial hydrogen pressure was set to 6 MPa. After raising the temperature to 0 ° C., the hydrogen pressure was set to 10 MPa, and the reaction was allowed to proceed for 4 hours while appropriately supplying the pressure decrease. The catalyst was filtered off, and cyclohexane was distilled off under reduced pressure to obtain rosins 1. The content of the component having a molecular weight of 320 measured by gas chromatography mass spectrometry of the methylated product is 100% of the total amount of the components having a molecular weight of 314 to 320, the color tone is 200H, the acid value is 174, and the softening point is 84.5 ° C. Met.

Production Example 2
600 g of Chinese hydrogenated rosin (manufactured by Guangxi Zhengzhou Nislin Industrial Chemical Co., Ltd.) was charged into a 1 liter flask and distilled under reduced pressure of 400 Pa to obtain a component distilled at 195 to 250 ° C. 200 g of the component distilled at 195 to 250 ° C., 3.0 g of 5% palladium carbon (water content 50%), and 200 g of cyclohexane were charged into a 1 liter autoclave, and the system was sufficiently replaced with hydrogen gas. After raising the pressure to 6 MPa and raising the temperature to 200 ° C., the hydrogen pressure was set to 10 MPa, and the reaction was carried out for 4 hours while appropriately supplying the pressure decrease. The catalyst was filtered off, and cyclohexane was distilled off under reduced pressure to obtain rosins 2. The content of the component having a molecular weight of 320 measured by gas chromatography mass spectrometry of the methylated product is 96% of the total amount of the components having a molecular weight of 314 to 320, the color tone is 200H, the acid value is 176 mgKOH / g, and the softening point is 84. It was 5 ° C.

Production Example 3
600 g of a Chinese disproportionated rosin (manufactured by Zhengzhou Songpu) was charged into a 1 liter flask and distilled under a reduced pressure of 400 Pa to obtain a component distilled at 195 to 250 ° C. 200 g of the component distilled at 195 to 250 ° C. and 0.1 g of 5% palladium carbon (water content 50%) were charged into a 1 liter autoclave and the system was sufficiently replaced with hydrogen gas. After raising the temperature to 200 ° C., the hydrogen pressure was set to 10 MPa, and the reaction was allowed to proceed for 4 hours while appropriately supplying the pressure decrease. The catalyst was filtered off, and cyclohexane was distilled off under reduced pressure to obtain rosins 3. The content of the component having a molecular weight of 320 measured by gas chromatography mass spectrometry of the methylated product is 31% of the total amount of the components having a molecular weight of 314 to 320, the color tone is 90H, the acid value is 167 mgKOH / g, and the softening point is 85. It was 5 ° C.

Production Example 4
600 g of Chinese hydrogenated rosin (manufactured by Guangxi Yinzhou Nislin Forestry Chemical Co., Ltd.) was charged into a 1 liter flask and distilled under a reduced pressure of 400 Pa. The content of the component having a molecular weight of 320 measured by gas chromatography mass spectrometry of the methylated product is 17% of the total amount of the components having a molecular weight of 314 to 320, the color tone is 250H, the acid value is 176 mgKOH / g, and the softening point is 79. It was 0 ° C.

Production Example 5
600 g of Chinese gum rosin (manufactured by Guangxi Arakawa Chemical Co., Ltd.) was charged into a 1-liter flask and distilled under reduced pressure of 400 Pa to obtain a component distilled at 195 to 250 ° C. 450 g of a component distilled at 195 to 250 ° C., 400 g of xylene, 20 g of zinc chloride and 3 g of sulfuric acid were charged, and the reaction was performed at 100 ° C. for 6 hours in a nitrogen atmosphere. The reactive organism was washed with 250 g of 1N hydrochloric acid and further washed twice with 250 g of warm water. After washing, the xylene solution was distilled off under conditions of a liquid temperature of less than 200 ° C. and a reduced pressure of 1,300 Pa, and further decomposed and unreacted substances under the conditions of a liquid temperature of 200 to 275 ° C. and a reduced pressure of 400 Pa. 35 g was distilled off to obtain a polymerized rosin. 250 g of the obtained polymer rosin, 250 g of cyclohexane, and 2.5 g of 5% palladium carbon (water content 50%) were charged into a 1 liter autoclave, and after removing oxygen in the system, the hydrogen pressure was adjusted to 10 MPa, and the pressure decreased appropriately. Was allowed to react for 4 hours. The catalyst was filtered off, and cyclohexane was distilled off under reduced pressure to obtain rosins 5. The content of the component having a molecular weight of 320 measured by gas chromatography mass spectrometry of the methylated product is 53% of the total amount of the components having a molecular weight of 314 to 320, the color tone is 300H, the acid value is 147 mgKOH / g, and the softening point is 142. It was 0 ° C.

(Quantification of content of component having molecular weight of 320 measured by gas chromatography mass spectrometry of methylated product)
Quantification was performed with the following gas chromatograph mass spectrometer.
For the measurement, 0.005 g of a sample (rosin) was dissolved in 0.5 g of an on-column methylating agent (phenyltrimethylammonium hydroxide (PTHA) 0.2 molar methanol solution, GL Sciences) and 1 μl was gas chromatographed. The measurement was carried out by injection into mass spectrometry (GC / MS). The ratio of the peak area of the component having a molecular weight of 320 to the total peak area of the components having a molecular weight of 314 to 320 was measured, and this was used as the content of the component having a molecular weight of 320.
Equipment used gas chromatograph: “Agilent 6890” (trade name, manufactured by Agilent Technologies Inc.)
Mass spectrometer: “Agilent 5973” (trade name, manufactured by Agilent Technologies Inc.)
Column: “Advanced-DS” (trade name, manufactured by Shinwa Kako Co., Ltd.)

(Color tone)
It was measured in Hazen units (H) according to JIS K0071-1. For the rosins of Comparative Examples 4 to 6, the Gardner color tone was measured according to JIS0071-2.

(Acid value)
It measured by the neutralization titration method according to JISK0070.

(Softening point)
It was measured by the ring and ball method according to JIS K 5902.

(Absorbance)
A sample (rosin) 25.0 mg is precisely weighed into a 25 ml volumetric flask, dissolved in cyclohexane, and then adjusted to a 25 ml weighing line. Absorbance is measured by using a quartz cell having a cell length of 1 cm with a UV spectrophotometer (HITACHI u-3210 spectrophotometer, manufactured by Hitachi, Ltd.). The maximum absorbance in the region of 254 nm or more was read. The results are shown in Table 1.

(Measurement of 99% weight loss temperature in thermogravimetry)
Using a sample (rosin), a differential thermal / thermogravimetric simultaneous measurement apparatus (trade name “TG / DTA220” manufactured by Seiko Instruments Inc.) at a heating rate of 5 ° C./min in a nitrogen atmosphere is 99. The% weight loss temperature was measured. Furthermore, the state of the residue after thermogravimetry was evaluated according to the following criteria. The results are shown in Table 1.
1: No residue is visually confirmed 2: A slight residue is confirmed, but the appearance is good 3: There is a black or brown residue, and the appearance is poor

Examples 1-2 and Comparative Examples 1-6
Using rosins 1-8, the heat stability of rosins, flux residue evaluation of cream solder flux and post flux (appearance and residue reduction rate) and solderability were evaluated by the following methods.
The results are shown in Table 1.

(Heating stability)
A sample (rosin) is placed in a test tube having an inner diameter of 1.5 cm and a height of 15 cm, and 10 g of the sample is placed in a circulating dryer at 120 ° C. in an air atmosphere, and the color tone over time (Gardner color tone, JIS0071-2). Measured according to the above). The evaluation of the heat stability of the rosins can be used as an index for estimating the heat resistance of solder flux and post flux containing rosins. Rosin having a good color tone after heating is considered to have heating stability that requires solder flux and the like.

(Preparation of flux for cream solder)
50 parts of a sample (rosins), 45 parts of diethylene glycol monohexyl ether and 5 parts of 12-hydroxystearic acid ethylene bisamide were dissolved by heating and then cooled to prepare a flux composition.

(Preparation of cream solder)
90 parts of solder powder (Sn—Ag—Cu alloy having an average particle diameter of 5 to 20 μn, 96.5 wt% / 3 wt% / 0.5 wt%) and 10 parts of the flux prepared by the above method were stirred. A cream solder was prepared.

(Solderability of cream solder)
The cream solder thus prepared was evaluated in accordance with “JIS Z3284 Appendix 10 Wetting Efficacy and Dewetting Test” and evaluated for solderability (wetting property). Both were good (○: Spreading degree category 1 or 2). Met.

(Cream solder flux residue evaluation)
1. Residue reduction rate Cream solder is screen printed on a copper substrate, and the resulting printed substrate is soldered in a nitrogen reflow furnace (preheating condition: 180 ° C. for 100 seconds, main heating condition: 240 ° C. for about 10 seconds) ), The residue (flux residue) weight on the substrate before and after soldering was measured, and the reduction rate of the flux residue was calculated by the following formula.
Residual reduction rate (%) = (solid content of flux in printed cream solder−amount of flux residue remaining on copper substrate) / (solid content of flux in printed solder paste) × 100
Solid content: flux components other than the solvent (diethylene glycol monohexyl ether) in cream solder Appearance Further, the soldering part was observed with a microscope VW-6000 (manufactured by Keyence Co., Ltd .: 30 times), whereby the color tone of the flux residue was visually judged based on the following criteria.
1: Flux residue is not noticeable 2: Flux residue is slightly noticeable 3: Flux residue is noticeable

(Preparation of post flux)
25 parts of a sample (rosins) and 75 parts of isopropyl alcohol were heated and dissolved, and then cooled to prepare a post flux.

(Post flux residue evaluation)
1. Reduction of post-flux residue by dropping 0.1 g of post flux on a 1 mm thick glass plate with a residue reduction rate of 18 mm x 60 mm, leaving it on a 270 ° C hot plate for 10 seconds, and measuring the weight before and after heating. The rate was calculated by the following formula.
Residual reduction rate (%) = (total amount of solid content in post flux−post flux residue amount remaining on glass plate) / (total amount of solid content in post flux) × 100
Solid content: flux components other than the solvent (isopropyl alcohol) in the post-flux 2. Appearance Also, the appearance was visually observed and evaluated according to the following criteria.
1: Post flux residue is not noticeable 2: Post flux residue is slightly noticeable 3: Post flux residue is noticeable

(Post flux solderability)
In accordance with “JIS Z3197 Solder Spreading Method”, the solderability (wetability) was evaluated and the spreading rate was calculated.

* 1: Rosin 6: Chinese gum rosin * 2: Rosin 7: Chinese disproportionated rosin * 3: Rosin 8: Chinese hydrogenated rosin

Claims (5)

The maximum absorbance A (measurement conditions: sample concentration 1 g / dm ³ , cell length 1 cm) in the region of 254 nm or more by ultraviolet absorption spectrophotometry is 0.15 or less, and was measured by gas chromatograph mass spectrometry of methylated products. A solder flux comprising a rosin (A) having a molecular weight of 320 component which is 95% or more of a total amount of components having a molecular weight of 314 to 320. The soldering flux according to claim 1, wherein the color tone of the rosin (A) is 300 Hazen or less. 3. The solder flux according to claim 1, wherein the rosin (A) is a rosin derivative having a 99% weight loss temperature of 500 ° C. or less in thermogravimetric measurement at a heating rate of 5 ° C./min. A solder composition containing the solder powder and the solder flux according to claim 1. The solder composition according to claim 4, wherein the solder powder is a lead-free solder powder.