TWI498184B - Solder flux and solder paste - Google Patents

Description

Flux and cream flux

This invention relates to a flux and a cream flux.

The flux is a function of cleaning, anti-oxidation, and promoting wetting of the metal surface to be welded. A rosin-based compound is widely used as a matrix agent in fluxes. As the rosin-based compound, hydrogenated rosin, disproportionated rosin, maleic acid-modified rosin, phenol-modified rosin, and the like are known. However, when these rosin-based compounds are used, any of the properties such as thermal stability and electrical insulating properties of the flux may be deteriorated due to the selected rosin-based compound.

As a method of improving the thermal stability and the electrical insulating property of the flux using the rosin-based compound, for example, a method of using a distilled purified product of hydrogenated rosin, disproportionated rosin or polymerized rosin as a rosin-based compound has been proposed (see Patent Document 1). According to this method, thermal stability and electrical insulation can be improved to some extent. However, it is still insufficient to suppress the occurrence of solder balls when the flux is used for flux.

In recent years, flux has been used in many cases in which a flux powder and a flux are mixed to form a paste flux. In the cream solder, it is a problem to suppress the generation of solder balls. As a method for solving this problem, a method of using a reaction product obtained by performing a Diels-Alder reaction with levopimaric acid and acrylic acid as a rosin-based compound has been proposed (refer to a patent) Literature 2). According to this method, the generation of the solder ball can be suppressed, and the cream flux having good solderability can be obtained. However, the electrical insulation of the obtained cream solder and the color residue prevention after reflow can be said to be insufficient.

Further, a method for producing a colorless polymerized rosin by hydrogenating a purified polymerized rosin is known (see Patent Document 3). However, no specific study has been conducted on the flux using the polymerized rosin.

[Patent Document 1] Japanese Patent Laid-Open No. 59-159298

[Patent Document 2] Japanese Patent Laid-Open No. Hei 6-39584

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2002-201433

An object of the present invention is to provide a flux excellent in electrical insulation and a cream flux using the same.

Another object of the present invention is to provide a cream flux which has less generation of solder balls, less coloration of residue after reflow, and good solderability.

The inventors of the present invention have made an effort to achieve the above problems. As a result, it has been found that the electrical insulation of the flux can be improved by setting the metal content of the rosin-based compound for the flux to a specific amount or less and lowering the electrical conductivity to a specific value or less. Further, it has been found that by using a specific rosin-based compound, the color tone of the flux can be made light and good; by using the flux, it is possible to suppress generation of solder balls, less coloration of residue after reflow, and soldering. Good cream solder. The present inventors completed the present invention based on the results of further studies based on these various findings.

The present invention provides the flux and paste flux shown below.

A flux comprising a rosin-based compound (A) having a metal content of 50 ppm or less and a conductivity of 1.0 μS/cm or less in a 20% by weight ethanol solution.

2. The flux according to item 1, wherein the content of the Group 1 element (excluding hydrogen) and the Group 17 element contained in the rosin-based compound (A) is 20 ppm or less.

3. The flux according to item 1, wherein the rosin-based compound (A) is obtained by hydrogenating an addition reactant of the α,β-unsaturated carboxylic acid (a) and the rosin (b).

4. The flux according to item 3 above, wherein the modification ratio of the α,β-unsaturated carboxylic acid of the rosin-based compound (A) is 30 to 70%.

5. The flux according to item 3 above, wherein the rosin compound (A) has a hydrogenation ratio of 30 to 60%.

6. The flux according to item 3 above, wherein the rosin-based compound (A) has a color tone of 2 or less in the Gardner colour.

7. The flux according to item 1, wherein the rosin-based compound (A) is a hydride of a polymerized rosin or a polymerized rosin.

8. The flux according to item 7, wherein the polymerized rosin is obtained by polymerizing the purified rosin.

A paste flux comprising a flux powder and a flux as in the above item 1.

10. The cream flux of item 9, wherein the flux powder is a lead-free solder powder.

11. The cream flux according to item 9 above, wherein the flux powder is 80 to 95% by weight and the flux is 20 to 5% by weight based on 100% by weight of the total amount of the cream flux.

Flux

The flux of the present invention is characterized in that it contains a rosin-based compound (A) having a metal content of about 50 ppm or less and a conductivity of about 1.0 μS/cm or less in a 20% by weight ethanol solution.

When the content of the metal contained in the rosin-based compound (A) exceeds 50 ppm, the electrical conductivity exceeds 1.0 μS/cm, and the electrical insulating properties become low, which is not preferable. Here, the term "metal" as used in the present invention means an element other than a Group 17 element, a Group 18 element, hydrogen, boron, carbon, nitrogen, oxygen, helium, phosphorus, sulfur, and selenium.

In the present specification, the metal content is a value measured by a wavelength dispersion type fluorescent X-ray analyzer, for example, "ZSX100e" (trade name, manufactured by Rigaku Electric Co., Ltd.).

Further, the rosin-based compound (A) is dissolved in ethanol to obtain a conductivity of 20% by weight of the compound solution, which is equivalent to electrical insulation when used as a flux, and a value higher than this value causes the flux to be electrically charged. Insulation deteriorates.

In the present specification, the conductivity of the rosin-based compound in a 20% by weight ethanol solution is measured by a conductivity measuring device, for example, "CONDUCTIVITY METER" (trade name, manufactured by Horiba, Ltd.).

Further, the content of the Group 1 element (excluding hydrogen) and the Group 17 element contained in the rosin-based compound (A) is set to be about 20 ppm or less, so that the electrical conductivity can be lowered, so that it is preferably set to Below 10ppm.

As the rosin-based compound (A), it is preferred to add an α,β-unsaturated carboxylic acid (a) and a rosin (b) addition reactant in terms of color shade and improvement in thermal stability. A rosin-based compound (AI) obtained by hydrogenation, and a rosin-based compound (A-II) as a polymerized rosin or a hydrogenated polymerized rosin.

Rosin compound (A-I)

The rosin-based compound (A-I) is obtained by hydrogenating an addition reactant of an α,β-unsaturated carboxylic acid (a) and rosin (b).

The α,β-unsaturated carboxylic acid (a) is not particularly limited, and those skilled in the art can be used. Specific examples thereof include (meth)acrylic acid, maleic acid (anhydride), fumaric acid, citraconic acid (anhydride), and itaconic acid (anhydride). Among these, in terms of the color tone of the obtained rosin-based compound and the reduction in brittleness, it is preferred to use acrylic acid.

The rosin (b) is not particularly limited, and those skilled in the art can be used. Specifically, it is preferred to use rosin such as gum rosin, wood rosin, high oil rosin, etc.; purified rosin and the like. Further, the component (b) is preferably purified by preliminarily removing the metal and further reducing the color tone. The purification method is not particularly limited, and specific examples thereof include distillation, recrystallization, and extraction.

When the (b) component is distilled, the distillation conditions are appropriately selected in the range of about 200 to 300 ° C and a pressure of about 130 to 1,300 Pa in consideration of the distillation time. When recrystallization is carried out, for example, the unpurified component (b) is dissolved in a good solvent, and then the solvent is distilled off to form a thick solution, and a poor solvent is added to the solution. Examples of the good solvent include benzene, toluene, xylene, chloroform, a lower alcohol having a carbon number of 1 to 3, a ketone such as acetone, and an acetate such as ethyl acetate. Examples of the poor solvent include n-hexane. n-Heptane, cyclohexane, isooctane, and the like.

Further, in addition to these methods, the unpurified (b) component is made into an alkaline aqueous solution using alkaline water, and the resulting insoluble unsaponifiable matter is removed by extraction with an organic solvent, and then the aqueous layer is neutralized. Thereby, the component (b) can be purified.

The addition reaction of the component (a) and the component (b) can be carried out by a well-known method. Specifically, for example, the addition reaction can be carried out by mixing the components (a) and (b) and heating at about 150 to 300 ° C for about 0.5 to 24 hours.

The ratio of use of the component (a) and the component (b) is not particularly limited. Usually, it is preferably 1 part or less per part of the component (b), and it is more preferable to set the component (a) to about 1 mole. It is set to about 0.05 to 0.75 moles, and particularly preferably set to about 0.10 to 0.70 moles. Further, the modification ratio of the rosin (b) modified by the α,β-unsaturated carboxylic acid (a) is set to about 30 to 70%, whereby the acid value of the finally obtained rosin-based compound (AI) becomes high, and The metal oxide removal activity is high, and therefore it is preferable. When it exceeds 70%, the brittleness of the rosin-based compound tends to increase. Further, the modification ratio is based on a peak area value of rosin (b) and a rosin modified based on α,β-unsaturated carboxylic acid, which is analyzed by gel permeation chromatography (GPC, Gel Permeation Chromatography). Peak area value, the value obtained by calculation.

The rosin-based compound (A-I) used in the present invention can be obtained by hydrogenating the α,β-unsaturated carboxylic acid-modified rosin obtained in the above manner. The hydrogenation is not particularly limited, and a well-known method can be employed. Specifically, for example, hydrogenation can be carried out by, in the presence of a hydrogenation catalyst, an α,β-unsaturated carboxy group under a pressure of hydrogen gas of usually about 1 to 25 MPa, preferably about 5 to 20 MPa. The acid-modified rosin is heated for about 0.5 to 7 hours, preferably about 1 to 5 hours. As the hydrogenation catalyst, a carrier catalyst such as palladium carbon, rhodium carbon, rhodium carbon or platinum carbon; a metal powder such as nickel or platinum; and an iodide such as iodine or iron iodide can be used. The amount of the catalyst used is usually preferably from 0.01 to 5 parts by weight, more preferably from 0.01 to 3.0 parts by weight, per 100 parts by weight of the α,β-unsaturated carboxylic acid-modified rosin. Further, the hydrogenation temperature is preferably about 100 to 300 ° C, more preferably about 150 to 290 ° C.

As for the hydrogenation, it is preferred to obtain a hydrogenation rate of about 30 to 60% in terms of obtaining a rosin-based compound having a light color tone, good thermal stability, and low crystallinity. In addition, the hydrogenation rate can be measured by gas chromatography, for example, "GC-14A" (trade name, manufactured by Shimadzu Corporation).

In the rosin-based compound (AI) which is a hydrogenated α,β-unsaturated carboxylic acid-modified rosin obtained by the above hydrogenation, a catalyst for hydrogenation or a catalyst-derived metal remains (particularly the first Since the group element (excluding hydrogen) and the group 17 element) have such a tendency, it is preferred to carry out further purification as needed. As for purification, it may be carried out by distillation, recrystallization, extraction or the like.

The metal content of the rosin-based compound (A-I) thus obtained is 50 ppm or less, and the electrical conductivity when the 20% by weight ethanol solution is prepared is 1.0 μS/cm or less. Further, the acid value is preferably about 200 to 340 mgKOH/g. Further, the color tone is usually such that the Gardner color number is 2 or less.

In the present specification, the color of the rosin-based compound (Gardner color number) is obtained by placing 10 g of the rosin-based compound to be placed in a test tube, heating and melting under a nitrogen stream, and then according to the "Gardner color number test" in accordance with JIS K0071. The method is a value obtained by measuring a person who heats and melts. As the standard solution of the Gardner color number, for example, a Gardner color standard liquid manufactured by Kishida Chemical Co., Ltd. can be used.

loose Fragrance Compound (A-II)

The rosin-based compound (A-II) is a polymerized rosin or a hydrogenated polymerized rosin.

The rosin-based compound (A-II) is a polymerized rosin or hydrogenated polymerized rosin having a reduced metal content. When the rosin-based compound (A-II) is a polymerized rosin, it can be obtained, for example, by polymerizing rosin (b) by a known method, and removing the metal component as needed until the metal component content reaches a desired amount. The method of the following, the method of carrying out the polymerization after reducing the metal component contained in the rosin (b). Further, when the rosin-based compound (A-II) is a hydrogenated polymerized rosin, it can be obtained by polymerizing rosin (b), hydrogenating it, and removing the metal component as necessary until the metal component content reaches a desired level. A method of reducing the amount of the metal component contained in the rosin (b), followed by polymerization and hydrogenation.

The rosin (b) used for the production of the rosin-based compound (A-II) is not particularly limited, and those skilled in the art can be used. Specifically, it is preferred to use rosin such as rosin gum, wood rosin, high oil rosin, etc.; purified rosin and the like. Further, in the same manner as in the case of producing the rosin-based compound (A-I), the component (b) can be removed by preliminarily removing the metal, and the color tone can be further lightened, which is preferable. The purification method of the component (b) is the same as the case of producing the rosin-based compound (A-I).

The polymerization of rosin (b) can be carried out by a well-known method, for example, by reacting in an organic solvent at a temperature of about 40 to 160 ° C for about 1 to 10 hours in the presence of a catalyst. . Examples of the catalyst include sulfuric acid, formic acid, p-toluenesulfonic acid, methanesulfonic acid, hydrogen fluoride, zinc chloride, aluminum chloride, titanium tetrachloride, and a sulfonated product of a styrene-divinylbenzene copolymer. As the catalyst, zinc chloride is preferred in terms of less side reactions such as decarbonation of rosin and good reaction activity, and it is usually used together with sulfuric acid. After the completion of the reaction, various well-known methods such as water washing and filtration can be usually used for removing the catalyst. Examples of the organic solvent include toluene, xylene, and a halogenated hydrocarbon. After the polymerization reaction, the unreacted rosin and its decomposition product can be removed by distillation under reduced pressure.

The polymerized rosin thus obtained is usually composed of a monomer which is an unreacted rosin, a dimer component which contains a dimerization of the above monomer, and a polymer having a polymerization degree larger than that of the dimer component. The mixture, the color tone (Gardner color number) is about 4~7. The content of the polymer in the polymerized rosin differs depending on the reaction temperature, the reaction time, the type of the catalyst, and the conditions for removing the unreacted rosin from the polymerization reaction, and therefore, in order to achieve the desired polymerization rosin content, The reaction conditions and the like can be appropriately selected. The polymer content in the polymerized rosin of the rosin derivative (A-II) is not particularly limited, and may be determined depending on the use of the flux or the like using the flux, and is usually about 10 to 85% by weight, preferably 20~80% by weight.

Further, when the rosin-based compound (A-II) is a hydrogenated polymerized rosin, hydrogenation may be carried out by various well-known methods after the polymerization of rosin (b). The hydrogenation is not particularly limited, and a well-known method can be employed. Specifically, for example, the polymerized rosin may be heated in the presence of a hydrogenation catalyst at a pressure of about 1 to 25 MPa, preferably about 5 to 20 MPa, for about 0.5 to 7 hours, preferably. It is about 1 to 5 hours. As the hydrogenation catalyst, a carrier catalyst such as palladium carbon, rhodium carbon, rhodium carbon or platinum carbon; a metal powder such as nickel or platinum; and an iodide such as iodine or iron iodide can be used. The amount of the catalyst used is usually from about 0.01 to about 5 parts by weight, preferably from about 0.01 to about 3.0 parts by weight, per 100 parts by weight of the polymerized rosin. Further, the hydrogenation temperature is about 100 to 300 ° C, preferably about 150 to 290 ° C. As for the hydrogenation, it is preferred to obtain a hydrogenation rate of about 30 to 60% in terms of obtaining a rosin-based compound having a light color tone, good thermal stability, and low crystallinity. In addition, the hydrogenation rate can be measured by a gas chromatograph, for example, "GC-14A" (trade name, manufactured by Shimadzu Corporation).

In the above-mentioned polymerized rosin or hydrogenated polymerized rosin, that is, the rosin-based compound (A-II), a catalyst or a catalyst-derived metal or the like which is used during polymerization or hydrogenation remains (particularly a group 1 element (excluding hydrogen)) Since the Group 17 element has such a tendency, it is preferred to further purify it as needed to have a metal content of 50 ppm or less. As for purification, it may be carried out by distillation, recrystallization, extraction or the like.

The metal content of the rosin-based compound (A-II) thus obtained is 50 ppm or less, and the electrical conductivity when the 20% by weight ethanol solution is prepared is 1.0 μS/cm or less. Further, the acid value is preferably about 130 to 180 mgKOH/g. Further, the color tone is usually 7 or less.

Flux

The flux of the present invention is characterized in that it contains a specific rosin-based compound (A) as a flux matrix agent, and further contains a well-known matrix agent, a solvent, a thixotropic agent, an active agent, and the like other than the component (A). Additives other than those.

The flux base agent other than the component (A) is not particularly limited, and those skilled in the art can be used. Specific examples thereof include rosin-based compounds other than the component (A) such as rosin gum, hydrogenated rosin, and disproportionated rosin; synthetic resins such as polyester resins, phenoxy resins, terpene resins, and polyamide resins; . In addition, when a flux base agent other than the component (A) is used in combination, for example, it is preferred to carry out the above-mentioned purification or the like to lower the amount of metal.

The solvent is not particularly limited, and those skilled in the art can be used. Specific examples thereof include alcohols such as ethanol, n-propanol, isopropanol and isobutanol; glycol ethers such as butyl carbitol and hexyl carbitol; isopropyl acetate, ethyl propionate and butyl benzoate; Esters such as esters and diethyl adipate; hydrocarbons such as n-hexane, dodecane and tetradecene.

The thixotropic agent is not particularly limited, and those skilled in the art can be used. Specifically, for example, hardened castor oil, beeswax, carnauba wax, stearylamine, hydroxyoctadecylethylenediamine or the like can be used.

The active agent exhibits an activity of removing the oxide film or the like. The active agent is not particularly limited, and those skilled in the art can be used. Specific examples thereof include amine hydrogen halides, organic acids, and organic amines.

The additive is not particularly limited as long as it is generally used for the preparation of a flux, and those skilled in the art can be used. Specifically, for example, an additive such as an antioxidant, an antifungal agent, or a matting agent may be contained.

The composition ratio of each component of the flux containing the flux base agent, the solvent, the thixotropic agent, and the active agent may be appropriately determined depending on various uses. The composition ratio is usually based on 100% by weight of the total flux, preferably about 30 to 75% by weight of the flux base agent, about 20 to 60% by weight of the solvent, and about 1 to 10% by weight of the thixotropic agent. The active agent is about 0.1 to 10% by weight.

The flux of the present invention is usually obtained by mixing a flux matrix agent, a solvent, a thixotropic agent, an active agent, and other additives as needed, by a well-known method. The flux of the obtained flux at 200 ° C is preferably about 50 to 500 mPa ‧ s.

Paste flux

The cream flux of the present invention contains a flux powder and the flux flux described above. The ratio of use of each component is not particularly limited. Usually, the flux powder is about 80 to 95% by weight and the flux is about 20 to 5% by weight based on 100% by weight of the total amount of the cream flux.

As the flux powder usable in the present invention, various well-known alloy constituents can be used. Specifically, as the flux alloy, for example, a tin-lead alloy, a lead-free alloy such as a tin-silver alloy or a tin-zinc alloy, and copper, bismuth, indium, antimony or the like may be added to the flux alloys. Adults and so on. Further, the particle diameter of the flux powder is not particularly limited, and is usually preferably in the range of about 1 to 100 μm, more preferably in the range of about 5 to 50 μm.

According to the present invention, a remarkable effect as described below can be produced.

(1) The flux of the present invention is extremely excellent in electrical insulation.

(2) In particular, a rosin-based compound (AI) obtained by hydrogenating an addition reactant of an α,β-unsaturated carboxylic acid (a) and rosin (b), or a rosin as a polymerized rosin or a hydrogenated polymerized rosin The compound (A-II) is a flux of the present invention as the rosin-based compound (A), and is excellent in color tone, heat stability, and the like.

(3) The solder ball of the present invention has less solder ball generation, less residue after reflow soldering, and good solderability.

Hereinafter, the present invention will be more specifically described by way of examples and comparative examples. However, the invention is not limited by the examples. Further, the softening point of the rosin-based compound in each of the examples is a value measured by the ring and ball method prescribed by JIS K5902. Further, the first group element in each case means a person other than hydrogen.

Example of the aspect of the flux containing the rosin-based compound (A-I)

Example 1

(1) Purification step of raw material rosin

An unpurified Chinese rosin gum 1,000 g having an acid value of 170 mg KOH/g, a softening point of 74 ° C, a Gardner color number of 6, and 500 g of xylene were placed in a flask, heated and dissolved, and about 350 g of xylene was distilled off. Then, 350 g of cyclohexane was introduced and cooled to room temperature. The supernatant was transferred to another flask by cooling to yield about 100 g of the crystal, and after recrystallization at room temperature, the supernatant was removed, and after washing with 100 g of cyclohexane, the solvent was distilled off to obtain a solvent. Purified rosin 700g.

(2) Addition reaction step

660 g of the purified rosin obtained in the above (1) and 100 g of acrylic acid were placed in a reaction vessel, and the reaction was carried out at 220 ° C for 4 hours while stirring under a nitrogen stream, and then the unreacted product was removed under reduced pressure, thereby obtaining an addition. The reaction product was 720 g.

(3) Hydrogenation step

500 g of the addition reaction product obtained in the above (2) and 5.0 g of 5% by weight of palladium carbon (water content: 50% by weight) were placed in a 1 L autoclave to remove oxygen in the system. The system was pressurized to 10 MPa with hydrogen gas and heated to 220 ° C, and hydrogenation reaction was carried out at this temperature for 3 hours to obtain 460 g of a colorless rosin compound.

(4) Purification step

400 g of the colorless rosin-based compound obtained in the above (3) and 200 g of xylene were placed in a flask, and the mixture was heated and dissolved, and then 150 g of xylene was distilled off, followed by 150 g of cyclohexane, and the mixture was cooled to room temperature. When the crystals were crystallized by cooling to about 40 g, the supernatant was transferred to another flask, and after recrystallization at room temperature, the supernatant was removed, and after washing with 20 g of cyclohexane, the solvent was distilled off. 280 g of a purified colorless rosin compound having an acid value of 245.8 mgKOH/g, a softening point of 132.0 ° C, and a Gardner color number of 1 or less was obtained. The content of the metal in the purified colorless rosin-based compound was 0 ppm, and the content of the Group 1 element and the Group 17 element was 0 ppm.

(5) Preparation of flux

50 parts by weight of the purified colorless rosin-based compound obtained in the above (4), 45 parts by weight of diethylene glycol monohexyl ether, and 5 parts by weight of 12-hydroxyoctadecyl ethylenediamine are placed in a container and heated. After dissolution, cooling is further carried out to prepare a flux of the present invention.

(6) Preparation of cream flux

A flux powder having a particle diameter of 25 to 38 μm (containing Sn of 96.5 wt%, Ag of 3% by weight, and Cu of 0.5 wt%) was used by using a stirring device (trade name "SOFTNER SPS-2", manufactured by Malcom Co., Ltd.). 90 parts by weight of the Sn-Ag-Cu alloy powder and 10 parts by weight of the flux prepared in the above (5) were mixed and stirred to prepare a paste flux of the present invention.

Example 2

(1) 100 g of the purified colorless rosin-based compound obtained in Example 1 (4) and 1 g of a 1,000 ppm aqueous sodium chloride solution were placed in a flask and re-dissolved to obtain an acid value of 245.8 mgKOH/g and a softening point of 132.0. °C, a colorless rosin compound having a Gardner color number of 1. The content of the metal in the purified colorless rosin-based compound was 10 ppm, and the content of the Group 1 element and the Group 17 element was 20 ppm.

(2) Preparation of flux and paste flux

The flux and paste flux of the present invention were prepared in the same manner as in Examples 1 (5) and (6) except that 50 parts by weight of the purified colorless rosin compound obtained in the above (1) was used.

Example 3

(1) 100 g of the purified colorless rosin-based compound obtained in Example 1 (4) and 7.2 mg of iron oxide (Fe ₂ O ₃ ) were placed in a flask and re-dissolved to obtain an acid value of 245.8 mgKOH/g and softened. A purified colorless rosin compound having a color of 132.0 ° C and a Gardner color number of 1. The content of the metal in the purified colorless rosin-based compound was 50 ppm, and the content of the Group 1 element and the Group 17 element was 0 ppm.

(2) Preparation of flux and paste flux

The flux and paste flux of the present invention were prepared in the same manner as in Examples 1 (5) and (6) except that 50 parts by weight of the purified colorless rosin compound obtained in the above (1) was used.

Comparative example 1

(1) In Example 2 (1), the same operation was carried out except that the amount of the 1,000 ppm aqueous sodium chloride solution was changed to 1.5 g, and the acid value was 245.8 mgKOH/g, and the softening point was 132.0. °C, a colorless rosin compound having a Gardner color number of 1. The content of the metal in the purified colorless rosin-based compound was 15 ppm, and the content of the Group 1 element and the Group 17 element was 30 ppm.

(2) Preparation of flux and paste flux

A comparative flux and a cream flux were prepared in the same manner as in Examples 1 (5) and (6), except that 50 parts by weight of the purified colorless rosin compound obtained in the above (1) was used.

Comparative example 2

(1) In Example 3 (1), the amount of iron oxide used was changed to 8.6 mg, and the same operation was carried out to obtain an acid value of 245.8 mgKOH/g, a softening point of 132.0 ° C, and Gardner. A purified colorless rosin compound having a color number of 1. The content of the metal in the purified colorless rosin-based compound was 60 ppm, and the content of the Group 1 element and the Group 17 element was 0 ppm.

(2) Preparation of flux and paste flux

A flux for comparison and a paste flux were prepared in the same manner as in Examples 1 (5) and (6), except that 50 parts by weight of the purified colorless rosin compound obtained in the above (1) was used.

Comparative example 3

(1) In Example 1, except that the purification step of (1) and the purification step of (4) were not carried out, an acid value of 247.6 mgKOH/g and a softening point were obtained in the same manner as in Example 1. It is a rosin compound having a color number of 3 at 130.5 ° C. The metal content of the rosin-based compound was 54 ppm, and the content of the Group 1 element and the Group 17 element was 24 ppm.

(2) Preparation of flux and paste flux

A flux for comparison and a paste flux were prepared in the same manner as in Examples 1 (5) and (6), except that 50 parts by weight of the rosin-based compound obtained in the above (1) was used.

Comparative example 4

(1) An unpurified Chinese rosin gum having an acid value of 168.0 mgKOH/g, a softening point of 76.0 ° C, and a Gardner color number of 7+ was used instead of the purified colorless rosin compound of Example 1 (4). The metal content in the unpurified rosin gum was 92 ppm, and the content of the Group 1 element and the Group 17 element was 24 ppm.

(2) Preparation of flux and paste flux

A flux for comparison and a paste flux were prepared in the same manner as in Examples 1 (5) and (6) except that 50 parts by weight of the rosin gum of the above (1) was used.

Performance evaluation

Each of the rosin-based compounds (including the unpurified rosin gum of Comparative Example 4) used in Examples 1 to 3 and Comparative Examples 1 to 4 was subjected to performance tests for heat stability, electrical conductivity, and electrical insulating properties. Further, the paste solders obtained in Examples 1 to 3 and Comparative Examples 1 to 4 were subjected to performance tests for solderability, solder balls, and residue color after reflow. The test method is as follows.

Performance test of rosin compounds

Heating stability test

10 g of the sample was placed in a test tube having an inner diameter of 1.5 cm and a height of 15 cm, and placed in a centrifugal dryer at 180 ° C without being covered, and the change of the Gardner color number with time was observed. . The Gardner color number is represented by a numerical value of 1 to 18, and the larger the value becomes, the stronger the coloring becomes. Further, as for the degree of coloring between the values, for example, in the range of "6" to "6+", "6 to 7", "7-", and "7", the coloring becomes thicker in the order of 6 to 7.

Conductivity test

20 g of a sample and 80 g of ethanol were placed in a jar having a capacity of 220 ml, and dissolved by shaking and stirring. Conductivity was measured on the dissolved 20% by weight ethanol solution by "CONDUCTIVITY METER" (trade name, manufactured by Horiba, Ltd.).

Electrical insulation test

Based on the above electrical conductivity, the electrical insulation properties at the time of forming the flux were evaluated in accordance with the following criteria.

◎: Conductivity is 0.5 μS/cm or less

○: Conductivity is more than 0.5 μS/cm and is 1.0 μS/cm or less

×: Conductivity exceeds 1.0 μS/cm

Paste flux performance test

Weldability test

The wetting efficiency and adhesion of the cream flux were evaluated in accordance with "JIS Z3284 Appendix 10 Wetting Effectiveness and Dehumidification Test". The judgment criterion is based on the distribution of the degree of diffusion as follows.

○: corresponds to the distribution of diffusion degree 1 or 2, and the weldability is good.

×: corresponds to the distribution of diffusion degree 3 or 4, poor weldability

Solder ball test

The generation of solder balls was evaluated in accordance with "JIS Z3284 Appendix 11 Solder Ball Test". The judgment criteria are as follows.

◎: The solder ball is less than 5, which is very good.

○: The number of solder balls is 5 or more and less than 10, which is good.

×: The number of solder balls is 10 or more, which is bad.

Residue color tone test after reflow

The degree of coloration of the residue on the copper substrate after the solderability test was visually evaluated. The judgment criteria are as follows.

○: colorless and transparent

Δ: a little coloring

×: There is coloring

Table 1 shows the test results of the performance tests of the rosin-based compounds of Examples 1 to 3 and Comparative Examples 1 to 4 and the respective cream fluxes.

Example of the aspect of the flux containing the rosin-based compound (A-II)

Example 4

(1) Purification step of raw material rosin

An unpurified Chinese rosin gum 2,000 g having an acid value of 170 mg KOH/g, a softening point of 74 ° C, a Gardner color number of 6, and 1,000 g of xylene were placed in a flask, heated and dissolved, and about 700 g of xylene was distilled off. Then, 700 g of cyclohexane was added and cooled to room temperature. When the crystal was about 200 g, the supernatant was removed, and the obtained crystal was dissolved in xylene in the same manner. After concentration, cyclohexane was added to crystallize, and then the supernatant was removed, and then washed with 200 g of cyclohexane. Thereafter, the solvent was distilled off to obtain 1,400 g of purified rosin.

(2) Polymerization step

In a reaction apparatus equipped with a thermometer, a stirrer, a nitrogen gas introduction tube, and a pressure reduction device, 900 g of purified rosin obtained in the purification step of the above (1), 900 g of xylene, 40 g of zinc chloride, and 6.0 g of sulfuric acid were placed under a nitrogen stream. The polymerization was carried out at 100 ° C for 6 hours. 7 g of concentrated hydrochloric acid and 500 g of warm water were added, and 1,845.9 g of the xylene solution of the reaction product was washed, and then washed twice with 500 g of warm water. The xylene solution after washing is subjected to distillation to remove xylene at a liquid temperature of less than 200 ° C and a reduced pressure of 1,300 Pa, and then, at a liquid temperature of 200 to 275 ° C and a reduced pressure of 400 Pa. The purified rosin decomposition product and 70 g of unreacted purified rosin were distilled off to obtain 471 g of purified polymeric rosin having an acid value of 135.3 mgKOH/g, a softening point of 146 ° C, and a Gardner color number of 5. The polymer content in the purified polymer rosin was confirmed to be 71.3% by weight and the monomer (purified rosin) was 27.2% by weight, as measured by GPC (polystyrene equivalent value by gel permeation chromatography). The content was 1.6% by weight.

(3) Hydrogenation step

250 g of the purified polymerized rosin obtained in the above (2), 250 g of cyclohexane, and 2.5 g of 5% by weight of palladium carbon (water content: 50% by weight) were placed in a 1 L rotary autoclave to remove oxygen in the system. The system was pressurized to 10 MPa with hydrogen gas and heated up to 240 ° C, and hydrogenation reaction was carried out at this temperature for 3 hours to obtain 200 g of a colorless polymerized rosin.

(4) Purification step

200 g of the colorless polymerized rosin obtained in the above (3) and 100 g of xylene were placed in a flask, and the mixture was heated and dissolved. Then, 75 g of xylene was distilled off, and then 75 g of cyclohexane was introduced, and the mixture was cooled to room temperature. The supernatant was transferred to a separate flask by cooling to obtain about 20 g of crystals, and after recrystallization at room temperature, the supernatant was removed, and after washing with 20 g of cyclohexane, the solvent was distilled off to obtain a solvent. 140 g of a rosin-based compound of a purified colorless polymerized rosin having an acid value of 145.2 mgKOH/g, a softening point of 140.0 ° C, and a Gardner color number of 7 or less (Hazen Color Number: 50). The content of the metal in the purified colorless polymerized rosin was 0 ppm, and the content of the Group 1 element and the Group 17 element was 0 ppm.

(5) Preparation of flux and paste flux

The flux and paste flux of the present invention were prepared in the same manner as in Examples 1 (5) and (6) except that 50 parts by weight of the rosin-based compound obtained in the above (1) was used.

Example 5

(1) 100 g of the purified colorless polymerized rosin obtained in Example 4 (4) and 1 g of a 1,000 ppm aqueous sodium chloride solution were placed in a flask and re-dissolved to obtain an acid value of 145.0 mgKOH/g and a softening point of 140.0 °C. A rosin-based compound of purified colorless polymerized rosin having a Gardner color number of 1 or less (having a strong color number of 80). The content of the metal in the purified colorless polymerized rosin was 10 ppm, and the content of the Group 1 element and the Group 17 element was 20 ppm.

(2) Preparation of flux and paste flux

The flux and paste flux of the present invention were prepared in the same manner as in Examples 1 (5) and (6) except that 50 parts by weight of the rosin-based compound obtained in the above (1) was used.

Example 6

(1) 100 g of the purified colorless polymerized rosin and 7.2 mg of iron oxide (Fe ₂ O ₃ ) obtained in Example 4 (4) were placed in a flask and re-dissolved to obtain an acid value of 145.8 mgKOH/g, and a softening point. A rosin-based compound of purified colorless polymerized rosin having a color of 140.5 ° C and a Gardner color number of 1 or less (having a Harjian color number of 80). The content of the metal in the purified colorless polymerized rosin was 50 ppm, and the content of the Group 1 element and the Group 17 element was 0 ppm.

(2) Preparation of flux and paste flux

The flux and paste flux of the present invention were prepared in the same manner as in Examples 1 (5) and (6) except that 50 parts by weight of the rosin-based compound obtained in the above (1) was used.

Example 7

(1) In Example 4, the acid value was 147.0 mgKOH/g, and the softening point was obtained in the same manner as in Example 4 except that the hydrogenation step of (3) and the purification step of (4) were not carried out. A rosin-based compound of purified polymerized rosin having a color of 5 at 141 ° C and a Gardner color number of 5. The content of the metal in the purified polymeric rosin was 0 ppm, and the content of the Group 1 element and the Group 17 element was 0 ppm.

(2) Preparation of flux and paste flux

The flux and paste flux of the present invention were prepared in the same manner as in Examples 1 (5) and (6) except that 50 parts by weight of the rosin-based compound obtained in the above (1) was used.

Example 8

(1) 100 g of the purified polymerized rosin obtained in Example 7 (1) and 1 g of a 1,000 ppm aqueous sodium chloride solution were placed in a flask and re-dissolved to obtain an acid value of 147.1 mgKOH/g and a softening point of 141.5 ° C. A rosin-based compound of a purified polymeric rosin having a Gardner color number of 5+. The content of the metal in the purified polymeric rosin was 10 ppm, and the content of the Group 1 element and the Group 17 element was 20 ppm.

(2) Preparation of flux and paste flux

The flux and paste flux of the present invention were prepared in the same manner as in Examples 1 (5) and (6) except that 50 parts by weight of the rosin-based compound obtained in the above (1) was used.

Example 9

(1) 100 g of the purified polymerized rosin obtained in Example 7 (1) and 7.2 mg of iron oxide (Fe ₂ O ₃ ) were placed in a flask and re-dissolved to obtain an acid value of 146.8 mgKOH/g and a softening point. A rosin-based compound of purified polymeric rosin having a color of 5+ at 140.5 ° C and a Gardner color number of 5+. The content of the metal in the purified polymerized rosin was 50 ppm, and the content of the Group 1 element and the Group 17 element was 0 ppm.

(2) Preparation of flux and paste flux

The flux and paste flux of the present invention were prepared in the same manner as in Examples 1 (5) and (6) except that 50 parts by weight of the rosin-based compound obtained in the above (1) was used.

Comparative Example 5

(1) In the same manner as in Example 5, the amount of the 1,000 ppm aqueous sodium chloride solution was changed to 1.5 g, and the same operation was carried out to obtain an acid value of 144.7 mgKOH/g and a softening point of 140.0 ° C. A rosin-based compound of purified colorless polymerized rosin having a nanocolor number of 1 or less (having a strong color number of 80). The content of the metal in the purified colorless polymerized rosin was 15 ppm, and the content of the Group 1 element and the Group 17 element was 30 ppm.

(2) Preparation of flux and paste flux

A flux for comparison and a paste flux were prepared in the same manner as in Examples 1 (5) and (6), except that 50 parts by weight of the rosin-based compound obtained in the above (1) was used.

Comparative Example 6

(1) In the same manner as in Example 6, except that the amount of iron oxide used was changed to 8.6 mg, the same operation was carried out to obtain an acid value of 145.3 mgKOH/g, a softening point of 140.5 ° C, and a Gardner color number. A rosin-based compound of purified colorless polymerized rosin having 1 or less (having a strong color number of 80). The content of the metal in the purified colorless polymerized rosin was 60 ppm, and the content of the Group 1 element and the Group 17 element was 0 ppm.

(2) Preparation of flux and paste flux

A flux for comparison and a paste flux were prepared in the same manner as in Examples 1 (5) and (6), except that 50 parts by weight of the rosin-based compound obtained in the above (1) was used.

Comparative Example 7

(1) In the same manner as in Example 8, except that the amount of the 1,000 ppm aqueous sodium chloride solution was changed to 1.5 g, the same operation was carried out, and an acid value of 146.7 mgKOH/g and a softening point of 141.0 ° C were obtained. A rosin-based compound of purified polymerized rosin having a nanocolor number of 5+. The content of the metal in the purified polymeric rosin was 15 ppm, and the content of the Group 1 element and the Group 17 element was 30 ppm.

(2) Preparation of flux and paste flux

A flux for comparison and a paste flux were prepared in the same manner as in Examples 1 (5) and (6), except that 50 parts by weight of the rosin-based compound obtained in the above (1) was used.

Comparative Example 8

(1) In the same manner as in Example 9, except that the amount of iron oxide used was changed to 8.6 mg, the same operation was carried out to obtain an acid value of 146.2 mgKOH/g, a softening point of 140.0 ° C, and a Gardner color number. 5+ purified rosin-based compound of polymerized rosin. The content of the metal in the purified polymeric rosin was 60 ppm, and the content of the Group 1 element and the Group 17 element was 0 ppm.

(2) Preparation of flux and paste flux

A flux for comparison and a paste flux were prepared in the same manner as in Examples 1 (5) and (6), except that 50 parts by weight of the rosin-based compound obtained in the above (1) was used.

Comparative Example 9

(1) In Example 4, the acid value was obtained in the same manner as in Example 4 except that the purification step of (1), the hydrogenation step of (3), and the purification step of (4) were not carried out. A rosin-based compound having a polymerized rosin of 140.6 mgKOH/g, a softening point of 138.5 ° C, and a Gardner color number of 9. The metal content in the polymerized rosin was 131 ppm, and the content of the Group 1 element and the Group 17 element was 66 ppm.

(2) Preparation of flux and paste flux

A flux for comparison and a paste flux were prepared in the same manner as in Examples 1 (5) and (6), except that 50 parts by weight of the rosin-based compound obtained in the above (1) was used.

Performance evaluation

Each of the rosin-based compounds used in Examples 4 to 9 and Comparative Examples 5 to 9 was subjected to a performance test of heat stability, electrical conductivity, and electrical insulating properties. Further, the paste fluxes obtained in Examples 4 to 9 and Comparative Examples 5 to 9 were subjected to performance tests for solderability, solder balls, and residue color after reflow. Each test method is as described above.

Table 2 shows the test results of the performance tests of the rosin-based compounds of Examples 4 to 9 and the respective cream fluxes.

Table 3 shows the test results of the performance tests of the rosin-based compounds of Comparative Examples 5 to 9 and the respective cream fluxes.

Claims (11)

A flux containing a rosin-based compound (A) having a metal content of 50 ppm or less and a conductivity of 1.0 μS/cm or less in a 20% by weight ethanol solution. The flux of claim 1, wherein the content of the Group 1 element (excluding hydrogen) and the Group 17 element contained in the rosin-based compound (A) is 20 ppm or less. The flux of claim 1, wherein the rosin-based compound (A) is obtained by hydrogenating an addition reactant of the α,β-unsaturated carboxylic acid (a) and rosin (b). The flux of claim 3, wherein the α,β-unsaturated carboxylic acid modification ratio of the rosin compound (A) is 30 to 70%. The flux of claim 3, wherein the rosin compound (A) has a hydrogenation rate of 30 to 60%. The flux of claim 3, wherein the rosin-based compound (A) has a color tone of 2 or less. The flux of claim 1, wherein the rosin compound (A) is a hydride of a polymerized rosin or a polymerized rosin. A flux according to claim 7, wherein the polymerized rosin is obtained by polymerizing the purified rosin. A cream flux comprising a flux powder and a flux as claimed in claim 1. The cream flux of claim 9, wherein the flux powder is a lead-free solder powder. The cream flux of claim 9, wherein the flux powder is 80 to 95% by weight and the flux is 20 to 5% by weight based on 100% by weight of the total amount of the cream flux.