JP2014014867A - Base resin for soldering flux, soldering flux, and solder paste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide new base resin for soldering flux in which fluidity of flux as well as viscosity stability and adhesiveness of solder paste are improved, and a color tone of flux residue and anti-crack resistance are excellent.SOLUTION: A rosin (A') including rosin (a-1) derived from slash pine and/or rosin (a-2) derived from merkus pine is purified, and is further subjected to a hydrogenation reaction and/or a disproportionation reaction so as to provide a product (A). Base resin for soldering flux includes the product (A).

Description

  The present invention relates to a base resin for soldered flux, a soldered flux, and a solder paste.

  For surface mounting of circuit boards, solder paste, which is a mixture of flux and solder powder, is usually supplied to the electrodes on the circuit board by methods such as screen printing and dispenser discharge, and electronic components such as capacitors are mounted on it. Thereafter, the circuit board is heated in a reflow furnace to melt the solder powder, and the electronic component and the electrode are joined.

  Conventionally, natural rosin has been used as a base resin for the flux. However, natural rosin is very easily oxidized and has poor thermal stability, such as being easily discolored under heating. For this reason, when natural rosin is used as the base resin for the flux, the residue generated at the solder joint is strongly colored, making subsequent inspection or cleaning difficult, or causing cracks to induce a migration phenomenon. Such a problem becomes particularly serious when a lead-free solder powder having a high melting point is used.

  Therefore, in this field, instead of natural rosin, so-called hydrogenated rosin or disproportionated rosin (see Patent Documents 1 and 2) having excellent thermal stability has been used (see Patent Document 3). As a result, when the natural rosin species used as the raw materials are different, the fluidity of the flux and the viscosity of the solder paste may greatly decrease over time, or the adhesiveness of the solder paste may be lost. It was found that there was.

JP-A-5-271622 JP-A-6-329991 Japanese Patent Laid-Open No. 11-73869

  The present invention provides a new base resin for soldered flux that improves the flowability of soldered flux and the viscosity stability and adhesiveness of solder paste, and also has good color tone and crack resistance of the flux residue. The main task is to do.

  As a result of intensive studies to solve the above problems, the present inventor has found that a rosin obtained from a specific pine seed is light-colored and a base resin capable of solving the above problems is sufficient.

  That is, the present invention purifies rosins (A ′) containing rosin (a-1) derived from slash pine and / or rosin (a-2) derived from Merck pine, and further hydrogenation reaction and / or The present invention relates to a soldered flux base resin comprising a product (A) obtained by a disproportionation reaction, a soldered flux containing the base resin, and a solder paste containing the soldered flux and solder powder.

  According to the base resin of the present invention, the fluidity of the soldered flux and the viscosity stability and adhesiveness of the solder paste are improved. Further, the base resin is excellent in thermal stability, and the color tone and crack resistance of the flux residue are also improved.

  In addition, the soldered flux of the present invention maintains its fluidity even after being stored at room temperature for a long time, thereby improving the viscosity stability and adhesiveness of the solder paste and the solderability (wetting property). . In addition, since the color tone of the flux residue generated after soldering is good, for example, inspection work is facilitated, and the cleaning process can be omitted. In addition, since cracks are unlikely to occur in the flux residue, problems relating to the electrical reliability of the circuit, such as migration accompanying adhesion of moisture, are also unlikely to occur.

  Further, the solder paste of the present invention is excellent in viscosity stability over time, is not only suitable for long-term storage, but also has good adhesive strength, and its change over time is small. Moreover, solderability (wetting property) is also good, and the color tone and crack resistance of the flux residue generated after soldering are also good.

  The product (A) according to the present invention is not only used as a flux base resin for solder paste, but also as a flux base in preflux or postlux (dip soldered flux), crab solder, yarn solder, etc. It is also useful as a resin. In particular, the post-flux containing the base resin of the present invention has excellent temporal stability, good solderability, and good color tone of the flux residue generated after soldering.

  The soldering flux base resin of the present invention includes rosin (a-1) derived from slash pine (hereinafter referred to as “component (a-1)”) and / or rosin derived from Merck pine (a-2). (Hereinafter referred to as “component (a-2)”) is purified, and further hydrogenation and / or disproportionation is performed. It is a product (A) obtained by reaction (hereinafter referred to as “component (A)”).

  The slash pine (Pinus elliottii) is a pine family plant mainly originating in the southeastern part of the United States, and is currently planted in China, Southeast Asia and Thailand. In particular, slash pine, which originates in China, is sometimes referred to as wetland pine.

  The component (a-1) is not particularly limited as long as it is a rosin derived from the slash pine. For example, raw pine oil collected from the slash pine, gum rosin obtained by distilling and purifying this, and slash pine wood Examples include tall oil rosin and wood rosin obtained by use.

  In addition, Pinus merukusii is a pine family plant mainly originating in Southeast Asia and grows in Vietnam, Cambodia, Indonesia, and so on. In addition, the Merkushi pine that originates in Laos is sometimes called Laos pine.

  The component (a-2) is not particularly limited as long as it is a rosin derived from the Merck pine, for example, raw pine oil collected from Merck pine, gum rosin obtained by distillation / purification of this, or Merck pine wood And tall oil rosin, wood rosin and the like obtained by using

The component (A ′) may contain rosins (a-3) (hereinafter referred to as “component (a-3)”) derived from pine trees other than the slash pine and the Merck pine. As such a pine, Pinus pine (Pinus)
massoniana), Yunnan pine (Pinus yunnanensis), Lion pine (Pinus sylvestris var. mongolica), Aleppo pine (Pinus)
halepensis) and the like.

  The content of the component (a-1) and / or the component (a-2) in the component (A ′) is not particularly limited, but usually 50% by weight or more is preferable in consideration of the intended effect of the present invention. Is about 60 to 100% by weight. Moreover, content of (a-3) component is less than 50 weight%, Preferably it is about 40 to 0 weight%.

  The component (A) can be obtained by purifying the component (A ′) by various known methods and further subjecting it to a hydrogenation reaction and / or a disproportionation reaction. In addition, when (a-1) component and (a-2) component are used, and also when (a-3) component is used, what mixed them is good also as (A ') component.

  As the purification step, various known methods such as a distillation method, an extraction method, and a recrystallization method can be employed. The distillation method can be carried out, for example, usually at a temperature of about 200 to 300 ° C. and a reduced pressure of about 0.01 to 3 kPa. In the extraction method, the component (A ′) (raw material rosin) may be an alkaline aqueous solution, the insoluble unsaponified product may be extracted with various organic solvents, and then the aqueous layer may be neutralized. Further, in the recrystallization method, there is a method in which the component (A ′) is dissolved in an organic solvent as a good solvent, then the solvent is distilled off to form a concentrated solution, and further an organic solvent as a poor solvent is added. .

  Various known methods can be adopted as the hydrogenation reaction. Specifically, the component (A ′) may be hydrogenated in the presence of a hydrogenation catalyst. The reaction temperature is usually about 100 to 300 ° C., the hydrogen pressure is about 1 to 25 MPa, and the reaction time is about 1 to 10 hours. Examples of the hydrogenation catalyst include palladium, rhodium, ruthenium, platinum and the like supported on carbon, alumina, silica, silica alumina, zeolite, etc .; metal powders such as nickel and platinum; iodine such as iodine and iron iodide And the like. The amount of the hydrogenation catalyst used is usually about 0.01 to 10% by weight relative to the component (A ′).

  Various known methods can be adopted as the disproportionation reaction. Specifically, the component (A ′) may be subjected to a disproportionation reaction in the presence of a disproportionation catalyst. In addition, reaction temperature is about 100-300 degreeC normally, reaction pressure is a normal pressure or less than 1 MPa, and reaction time is about 1 to 10 hours. Further, as the disproportionation catalyst, the same one as the above-described hydrogenation catalyst can be used, and the amount used is usually about 0.01 to 10% by weight with respect to the component (A ′).

  The physical properties of the component (A) thus obtained are not particularly limited. For example, the color tone is preferably a Gardner color tone of 2 or less in consideration of the temporal stability of the flux and solder paste and the color tone (transparency) of the flux residue. .

  In consideration of flux activity and solder paste solderability (wetting), the acid value (JIS K 5902) of component (A) is usually about 150 to 190 mg KOH / g, and the softening point (JIS K 5902) is usually normal. It is about 70-90 degreeC.

  The first flux of the present invention comprises a base resin (component (A)) of the present invention, a flux solvent (B) (hereinafter referred to as component (B)) and a thixotropic agent (C) (hereinafter referred to as (C). And a composition containing an active agent (D) (hereinafter referred to as component (D)) as necessary. The composition is particularly suitable as a solder paste flux.

  Moreover, the 2nd flux of this invention is a composition which contains (A) component, (B) component, and (D) component as needed, and does not contain a thixotropic agent (C). The composition can be used particularly as a flux in fluxes other than solder paste flux, such as pre-flux and post-lux (flux for dip solder), solder with solder, yarn solder, etc., and particularly suitable as post-flux. is there.

  As the component (B), various known compounds can be used without particular limitation. Specifically, for example, ether alcohols such as diethylene glycol monohexyl ether, diethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monoethyl hexyl ether, butyl carbitol, hexyl carbitol; isopropyl alcohol, octanediol, benzyl alcohol 1,3-butanediol, 1,4-butanediol, 2- (2-n-butoxyethoxy) ethanol, terpineol, benzyl alcohol, and other non-ether alcohols; isopropyl acetate, ethyl propionate, butyl benzoate, Esters such as diethyl adipate; hydrocarbons such as n-hexane, dodecane and tetradecene; pyrrolidones such as N-methyl-2-pyrrolidone It is. Among these, when the flux of the present invention is used as a solder paste, the ether alcohols having a high boiling point are preferable in consideration of the temperature during reflow (usually 230 to 260 ° C.), and particularly the boiling point is 230 to Ether-based alcohols at about 260 ° C. are preferred. Further, when the flux of the present invention is used as a flux other than the solder paste flux, particularly as a post flux, non-ether alcohols are preferred.

  Examples of the component (C) include animal and plant thixotropic agents such as castor oil, hydrogenated castor oil, beeswax and carnauba wax; amide thixotropic agents such as stearamide and 12-hydroxystearic acid ethylenebisamide. These can be used alone or in combination of two or more. The flux of the present invention containing the component (C) is suitable for solder paste applications, and the screen printing suitability of the solder paste can be adjusted by the component (C).

  (D) component can be used as needed for the purpose of improving the wettability at the time of fusion | melting of the solder metal which applies the flux of this invention by supplementing the active effect | action of (A) component of this invention. Specifically, for example, monocarboxylic acids such as palmitic acid, stearic acid, benzoic acid and picolinic acid; dicarboxylic acids such as succinic acid, adipic acid, glutaric acid, azelaic acid, sebacic acid, dodecanedioic acid and dimer acid; 1-bromo-2-butanol, 1-bromo-2-propanol, 3-bromo-1-propanol, 3-bromo-1,2-propanediol, 1,4-dibromo-2-butanol, 1,3-dibromo -2-propanol, 2,3-dibromo-1-propanol, 1,4-dibromo-2,3-butanediol, 2,3-dibromo-1,4-butenediol, 2,3-dibromo-2-butene Bromo alcohols such as 1,4-diol and 2,2-bis (bromomethyl) -1,3-propanediol; ethylamine hydrobromide, die Hydrohalogenates of organic amines such as ruamine hydrobromide and methylamine hydrobromide; Bromo such as 1,2,3,4-tetrabromobutane and 1,2-dibromo-1-phenylethane Alkanes; bromoalkenes such as 1-bromo-3-methyl-1-butene, 1,4-dibromobutene, 1-bromo-1-propene, 2,3-dibromopropene, 1,2-dibromostyrene; 4 -Stearoyloxybenzyl bromide, 4-stearyloxybenzyl bromide, 4-stearylbenzyl bromide, 4-bromomethylbenzyl stearate, 4-stearoylaminobenzyl bromide, 2,4-bisbromomethylbenzyl stearate, 4-palmitoyl Oxybenzyl bromide, 4-myristoyloxybenzyl bromide, 4 Benzyl bromides such as lauroyloxybenzil bromide, 4-undecanoyloxybenzyl bromide; N, N′-bis (4-aminobutyl) -1,2-ethanediamine, triethylenetetramine, N, N′— And polyamines such as (3-aminopropyl) ethylenediamine and N, N′-bis (3-aminopropyl) piperazine; and chlorine-based activators such as diethylamine hydrochloride. A combination of more than one species can be used.

  The flux of the present invention further includes a base resin (E) other than the component (A) (hereinafter referred to as (E) component) and an additive (hereinafter referred to as (F) component) as necessary. May be.

  As the component (E), the components (a-1) to (a-3) and purified products thereof; other raw material rosins and purified products (purified rosins); and other raw material rosins as raw materials. In addition to rosin base resins other than component (A) such as disproportionated rosin, hydrogenated rosin, formylated rosin, polymerized rosin, epoxy resin, acrylic resin, polyimide resin, polyamide resin (nylon resin), polyester resin, Examples thereof include synthetic resins such as polyacrylonitrile resin, vinyl chloride resin, vinyl acetate resin, polyolefin resin, fluorine-based resin, and ABS resin.

  Examples of the component (F) include antioxidants, antifungal agents, and matting agents. Examples of the antioxidant include pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl). -5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (N-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, 2,2-thio-diethylenebis [3- (3,5-di- t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N′-hexa Tylene bis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 3,5-di-tert-butyl-4-hydroxybenzylphosphonate-diethyl ester, 1,3,5-trimethyl- Hindered phenolic antioxidant of 2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene; 2,6-di-t-butyl-p-cresol, 2,4 -Other phenolic antioxidants such as dimethyl-6-tert-butyl-phenol, styrenate phenol, 2,4-bis [(octylthio) methyl] -o-cresol; triphenyl phosphite, triethyl phosphite, tri Phosphorous antioxidants such as lauryl trithiophosphato, tris (tridecyl) phosphite; dilauryl thiodipropionate, Lauryl sulfide, 2-mercaptobenzimidazole, can be exemplified and sulfur-based antioxidants such as lauryl stearyl thiodipropionate, they alone, or used in combination of two or more.

The content of each component in the flux can be appropriately set according to the usage mode of the flux. For example, when the flux is used for solder paste, the content of each component is, for example, as follows.
Component (A): about 20 to 60% by weight, preferably 30 to 60% by weight
Component (B): about 60 to 20% by weight, preferably 55 to 30% by weight
Component (C): about 0 to 20% by weight, preferably 1 to 10% by weight
Component (D): about 0 to 20% by weight, preferably 1 to 10% by weight
Component (E): about 0 to 20% by weight, preferably 0 to 10% by weight
Component (F): about 0 to 10% by weight, preferably 1 to 5% by weight

Moreover, when using this flux for fluxes other than the solder paste flux, the content of each component is, for example, as follows, and a flux having such a composition is particularly suitable as a post flux.
Component (A): about 20 to 60% by weight, preferably 25 to 50% by weight
Component (B): about 80 to 40% by weight, preferably 70 to 45% by weight
Component (C): 0% by weight
Component (D): about 0 to 10% by weight, preferably 1 to 5% by weight
Component (E): about 0 to 10% by weight, preferably 0 to 5% by weight
Component (F): about 0 to 10% by weight, preferably 1 to 5% by weight

  The solder paste of the present invention contains the flux of the present invention and solder powder. Although each content is not specifically limited, Usually, the former is about 5 to 20% by weight, and the latter is about 80 to 95% by weight. The solder paste can be produced by various known means (planetary mill or the like).

  As the solder powder, conventional lead eutectic solder powder such as Sn-Pb solder powder; Sn solder powder, Sn-Ag solder powder, Sn-Cu solder powder, Sn-Zn solder powder, Sn-Sb solder Solder powder, Sn-Ag-Cu solder powder, Sn-Ag-Bi solder powder, Sn-Ag-Cu-Bi solder powder, Sn-Ag-Cu-In solder powder, Sn-Ag-Cu-S And lead-free solder powders such as Sn solder powder and Sn-Ag-Cu-Ni-Ge solder powder. In addition, although the average primary particle diameter of solder powder is not specifically limited, Usually, it is about 1-50 micrometers, Preferably it is about 20-40 micrometers.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, as a matter of course, the scope of the present invention is not limited by them. “Part” and “%” are both based on weight.

(Preparation of base resin (A))
Production Example 1
200 g of gum rosin obtained from Chinese slash pine (Gardner color tone 7, acid value 170, softening point 77 ° C .; hereinafter referred to as “raw material 1”) was placed in a vacuum distillation vessel, and under a vacuum of 0.4 kPa under a nitrogen seal And purified rosin was obtained. Next, 150 g of the purified rosin and 0.7 g of 5% palladium carbon (water content 50%) were charged into a 0.3 liter rotary autoclave to remove oxygen in the system, and then pressurized to 10 MPa with hydrogen at 220 ° C. The base resin (A1) was obtained by performing a hydrogenation reaction at the same temperature for 3 hours. Table 1 shows the physical properties of the base resin (A1) (hereinafter the same).

Production Example 2
In Production Example 1, gum rosin (Gardner color tone 8, acid value 185, softening point 81 ° C .; hereinafter referred to as “raw material 2”) 200 g obtained from Indonesian Merck pine was used as the raw material rosin. Base resin (A2) was obtained.

Production Example 3
In Production Example 1, as raw material rosin, 6: 4 (weight) of raw material 2 and gum rosin (Gardner color tone 7, acid value 171, softening point 78 ° C .; hereinafter referred to as “raw material 3”) obtained from Mao pine from China. Ratio) A base resin (A3) was obtained in the same manner except that 200 g of the mixture was used.

Production Example 4
A base resin (A4) was obtained in the same manner as in Production Example 1 except that 200 g of a 5: 5 (weight ratio) mixture of Raw Material 1 and Raw Material 2 was used as the raw material rosin.

Production Example 5
250 g of a 9: 1 (weight ratio) mixture of raw material 1 and raw material 3 was charged into a vacuum distillation vessel and distilled under a vacuum of 0.4 kPa under a nitrogen seal to obtain a purified rosin. Next, 200 g of the purified rosin and 0.4 g of 5% palladium carbon (water content 50%) are charged into a 0.5 liter flask, heated to 260 ° C. in a nitrogen atmosphere, and subjected to a disproportionation reaction at the same temperature for 3 hours. As a result, a base resin (A5) was obtained.

Comparative production example 1
A base resin (I) was obtained in the same manner as in Production Example 1 except that 200 g of raw material 3 was used as the raw material rosin. Table 2 shows the physical properties of the base resin (A) (hereinafter the same).

Comparative production example 2
In Production Example 1, gum rosin (Gardner color tone 7, acid value 170, softening point 78 ° C .; hereinafter referred to as “raw material 4”) 200 g obtained from Yunnan pine produced in China was used as the raw material rosin. Base resin (b) was obtained.

Comparative production example 3
200 g of an 8: 2 mixture of raw material 2 and raw material 3 was placed in a vacuum distillation vessel and distilled under a vacuum of 0.4 kPa under a nitrogen seal to obtain a base resin (c).

Comparative production example 4
200 g of raw material 3, 0.7 g of 5% palladium carbon (moisture content 50%), 0.7 g, charged in a 0.3 liter rotary autoclave, and after removing oxygen in the system, pressurized to 10 MPa with hydrogen, up to 220 ° C. The temperature was raised and a hydrogenation reaction was carried out at the same temperature for 3 hours to obtain a base resin (d).

Comparative Production Example 5
200 g of material 3, 0.06 g of 5% palladium carbon (water content 50%), charged in a 0.5 liter flask, heated to 280 ° C. in a nitrogen atmosphere, and allowed to disproportionate at that temperature for 3 hours. As a result, a base resin (e) was obtained.

Examples 1-5 and Comparative Examples 1-5
<Manufacture of solder paste flux and solder paste>
Flux for solder paste is prepared by placing 50 parts of component (A1) obtained in Production Example 1, 5 parts of 12-hydroxystearic acid ethylenebisamide, and 45 parts of diethylene glycol monohexyl ether in a beaker and heating and melting under stirring. did. Next, by stirring and mixing 10 parts of the flux and 90 parts of lead-free solder powder (Sn—Ag—Cu alloy; 96.5 wt% / 3 wt% / 0.5 wt%, average particle size 25 to 38 μm) A solder paste was prepared. For the base resins obtained in Production Examples 2 to 5 and Comparative Production Examples 1 to 5, solder paste flux and solder paste were prepared in the same manner.

<Flux test for solder paste>
(Stability over time)
After the solder paste fluxes of Examples 1 to 5 and Comparative Examples 1 to 5 were stored at room temperature for 1 month, the fluidity was confirmed according to the following criteria. The results are shown in Table 3.
1: Flows at room temperature.
2: Although it does not flow at room temperature, it is soft and easy to stir.
3: Solidified at room temperature and difficult to stir.

<Solder paste test>
(Stability over time)
After the solder pastes of Examples 1 to 5 and Comparative Examples 1 to 5 were stored at 40 ° C. for 7 days, the viscosity was measured by an automatic viscosity measuring apparatus PCU-205 (manufactured by Malcolm Co., Ltd.), and the paste was prepared (0 days) The change in viscosity from the eye) was confirmed. The smaller the viscosity change, the better the stability over time. The results are shown in Table 3.
1: Change in viscosity is less than 20 Pa · S 2: Change in viscosity is 20 Pa · S or more and less than 40 Pa · S 3: Change in viscosity is 40 Pa · S or more

(Adhesive)
The solder pastes of Examples 1 to 5 and Comparative Examples 1 to 5 were printed on a copper plate, and the adhesive strength was measured with a tackiness tester TK-1 (manufactured by Malcolm). The larger the value, the better the adhesiveness. The results are shown in Table 3.
1: Measurement value is 80 gf or more 2: Measurement value is 30 gf or more and less than 80 gf 3: Measurement value is less than 30 gf

(Solderability)
The solder pastes of Examples 1 to 5 and Comparative Examples 1 to 5 were evaluated for solderability (wetability) in accordance with “JIS Z3284 Annex 10 Wetting Efficacy and Dewetting Test”. The solderability was also good (spreading degree category 1 or 2).

(Flux residue color tone)
The solder pastes of Examples 1 to 5 and Comparative Examples 1 to 5 are printed on a copper substrate, and the soldered part is observed with a microscope VW-6000 (manufactured by Keyence Corporation: 30 times), whereby the color tone of the flux residue Was confirmed according to the following criteria. The results are shown in Table 3.

1: colorless and transparent 2: slightly colored 3: colored

(Flux residue cracks)
Together with the evaluation of the color tone of the flux residue, the presence or absence of cracks was confirmed. In any of the solder pastes of Examples 1 to 5 and Comparative Examples 1 to 5, no cracks were observed in the residue.

Examples 6 to 10 and Comparative Examples 6 to 10
<Post flux production>
A post flux was prepared by putting 50 parts of the component (A1) obtained in Production Example 1 and 50 parts of isopropyl alcohol into a beaker and heating and melting them under stirring. Post fluxes were similarly prepared for the rosins obtained in Production Examples 2 to 5 and Comparative Production Examples 1 to 5.

<Post flux test>
(Stability over time)
After the post fluxes of Examples 6 to 10 and Comparative Examples 6 to 10 were stored at room temperature for 1 week, the generation of precipitates was evaluated according to the following criteria. The less precipitate is generated, the better the stability over time. The results are shown in Table 4.
1: No precipitate is generated at all.
2: A slight precipitate is generated.
3: Precipitates are considerably generated.

(Solderability)
Using the post-flux of Examples 6 to 10 and Comparative Examples 6 to 10, the solderability (wetting property) was evaluated in accordance with “JIS Z3197 Solder Spreading Method”. (Expansion degree category 1 or 2).

(Flux residue color tone)
Moreover, the color tone of the flux residue was confirmed according to the following criteria by observing the soldered portion with a microscope VW-6000 (manufactured by Keyence Corporation: 30 times). The results are shown in Table 4.
1: colorless and transparent 2: slightly colored 3: colored

  From the results of Examples 1 to 5, the solder paste flux using the component (A) as a base resin has good temporal stability, and the solder paste using this flux is also excellent in viscosity temporal stability and adhesiveness. I understood it. The solder paste also had good solderability (wetability), color tone of the flux residue, and crack resistance.

  On the other hand, from the results of Comparative Examples 1, 2, 4, and 5, the case where the component (A-1) or the component (a-2) is not contained in the component (A ′) or the purification treatment is performed even if it is contained. It was found that when the soldering was not performed, the flux stability with time and the viscosity stability and tackiness of the solder paste were poor. Moreover, in the case of the comparative example 4, the color tone of the flux residue was also not good.

  Moreover, from the result of Comparative Example 3, even if the component (A ′) or the component (a-2) is contained in the component (A ′), both the hydrogenation reaction and the disproportionation reaction are allowed to pass through. When it was not, the viscosity stability of the solder paste was poor, and it was found that the color tone of the flux residue was not good.

  From the results of Examples 6 to 10, the post-flux having the component (A) as a base resin has good temporal stability, and solderability (wetting) and the color tone of the flux residue when using this flux are also shown. It was good.

  On the other hand, from the results of Comparative Examples 6, 7, 9 and 10, the case where the component (A-1) or the component (a-2) is not included in the component (A ′) or the purification treatment is performed even if it is included. It was found that the stability of the postflux with time is poor when no is performed. In the case of Comparative Example 9, the color tone of the flux residue was not good.

Moreover, from the result of Comparative Example 8, even if the component (A-1) or the component (a-2) is contained in the component (A ′), both the hydrogenation reaction and the disproportionation reaction are allowed to pass through. If not, it was found that the color tone of the flux residue was not good.

Claims (8)

The rosin (A ′) containing rosin (a-1) derived from slash pine and / or rosin (a-2) derived from Merck pine is purified, and further hydrogenated and / or disproportionated. Soldering flux base resin comprising the product (A) obtained in this manner. The base resin for soldered flux according to claim 1, wherein the content of the component (a-1) and / or the component (a-2) in the component (A ') is 50% by weight or more. The base resin for soldered flux according to claim 1 or 2, wherein the (A) component has a Gardner color tone of 2 or less. The base resin for soldered flux according to any one of claims 1 to 3, wherein the acid value of the component (A) is 150 to 190 mgKOH / g. The base resin for soldered flux according to any one of claims 1 to 4, wherein the softening point of the component (A) is 70 to 90 ° C. Soldering flux containing the soldering flux base resin according to any one of claims 1 to 5, the fluxing solvent (B) and the thixotropic agent (C), and optionally the activator (D). Soldering flux containing the base resin for soldering flux according to any one of claims 1 to 5, the solvent for flux (B) and optionally the activator (D) and not containing the thixotropic agent (C). A solder paste containing the soldered flux and solder powder of claim 6.