JP2012086269A - Rosin-based flux for soldering and solder paste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide rosin-based flux for soldering hardly scattered in soldering, and moreover, capable of suppressing heating droop of a solder paste.SOLUTION: As a base material, a rosin derivative hydride including a maleopimaric acid anhydride and having a melt viscosity of 100-1,000 mPa s/180°C is used.

Description

  The present invention relates to a rosin flux for soldering and a solder paste.

  As electronic devices become more sophisticated, smaller and lighter, components and patterns have become smaller and finer than before, and surface-mount substrates are no longer manufactured without a micro soldering technique called micro soldering. It is an era when it cannot be done.

  In micro soldering, solder paste, which is a mixture of paste-like flux and powder-like solder alloy, is usually screen-printed on a small terminal electrode provided on the substrate, and then the printed substrate is heated called a reflow oven. Soldering is performed by passing it through a furnace. Also, in a reflow furnace, a main heating called a main heat for melting a solder alloy is usually performed after a preheating called a preheating, but when a lead-free alloy is used as the solder alloy, the temperature of the main heat is increased. May exceed 300 ° C.

  In general, a rosin flux based on rosins or derivatives thereof is often used as the flux. This is because the action of maintaining the shape of the solder paste placed on the terminal electrode during preheating and the action of promoting the wetting of the solder alloy and the terminal electrode (active action) during the main heating are obtained. .

  However, since rosins and their derivatives are generally thermoplastic materials, the solder paste may be heated on the terminal electrodes during soldering. In particular, when a lead-free solder alloy is used, the temperature of the main heat becomes high, so heating is likely to occur. In severe cases, unmelted solder powder flows out around the terminal electrode together with the flux, and solder balls and terminal electrodes In some cases, the insulation reliability of the surface mount substrate may be significantly impaired.

  Therefore, it has been studied to solve the problem of heating without using rosins. For example, Patent Document 1 discloses a flux using a hydride of an alcohol-modified dicyclopentadiene resin. However, the effect is not enough.

  Also, since rosins are natural products and contain various low-boiling components, when rosin flux is used, the flux components scatter from the solder paste during soldering, and the surface of the mounting board or inside the reflow furnace May adhere to large amounts. In particular, if residue adheres to the connector pattern, etc., it may cause insulation failure, so the industry has taken measures such as incorporating a flux recovery device in a reflow furnace or cleaning the mounting board after soldering. , Both of which are not desirable because they lead to complicated manufacturing processes and high costs.

  Various means are known as means for preventing flux scattering. For example, Patent Document 2 proposes a rosin-based flux using distilled rosin in which the content of low-boiling components is adjusted to less than 7% by weight. . However, there is a problem that the solder paste is easily heated in the reflow furnace and a lot of solder balls are generated.

JP 2009-154170 A JP 2008-62241 A

  It is a main object of the present invention to provide a rosin-based flux that can suppress the solder paste from being heated and has almost no scattering during soldering.

  As a result of intensive studies, the present inventor has developed a rosin derivative hydrogen containing a maleopimaric anhydride (a-1) represented by the following structural formula (1) and having a melt viscosity of 100 to 1000 mPa · s / 180 ° C. It has been found that the above-mentioned problem can be solved by a flux containing the chemical (A).

(In formula (1), the broken line means that a carbon-carbon bond may exist there.)

  According to the rosin flux for soldering of the present invention (hereinafter sometimes simply referred to as “flux”), a solder paste can be obtained with little heating dripping and flux component scattering during soldering. Moreover, since the solder joint is covered with a flux residue having excellent crack resistance, it is considered that migration due to adhesion of moisture hardly occurs. In addition, since the film is excellent in color tone, the finished feeling and visibility of the mounting substrate are improved. In addition, since such an effect can be obtained in the same manner when lead-free solder powder having a high melting point is used, the flux of the present invention is particularly suitable for use in lead-free solder. In addition, the rosin flux for soldering of the present invention is also suitable as a post flux for coating the terminal electrode or a flux used for the solder that enters the terminal.

  The flux of the present invention comprises, as a base material, a rosin derivative hydride (A) containing a maleopimaric anhydride (a-1) represented by the following structural formula (1) (hereinafter referred to as component (a-1)) ( Hereinafter, (A) component) is used.

(In formula (1), the broken line means that a carbon-carbon bond may exist there.)

  Specifically, the formula (1) means dihydromaleopimaric acid represented by the following structural formula (1-2) and / or maleopimaric anhydride represented by the following structural formula (1-3).

  The method for producing the component (A) is not particularly limited. For example, (a) a method of hydrogenating a Diels-Alder reaction product of α, β-unsaturated dicarboxylic acids and rosins, or (a) the Diels-Alder reaction. A method using a hydride of a modified resin acid isolated from a product by a known method (see US Pat. No. 2,628,226, etc.), (u) Levopimaric acid isolated from a rosin by a known method (J. Am. Chem. Soc., 70, 334 (1948), etc.) and a hydride of a Diels-Alder reaction product of α, β unsaturated dicarboxylic acids. Industrially, method (a) is simple and will be described in detail below.

  Examples of α, β unsaturated dicarboxylic acids include maleic anhydride, maleic acid, fumaric acid and the like. Examples of rosins include raw material rosins such as gum rosin, wood rosin and tall oil rosin. The raw rosins are purified by means of a vacuum distillation method, a steam distillation method, an extraction method, a recrystallization method or the like from the viewpoint of heat dripping resistance, suppression of solder balls, color tone of the flux residue, etc. It is preferably used as a product from which the components have been removed (hereinafter referred to as purified rosin).

  The conditions of the purification means are not particularly limited. For example, in the case of a vacuum distillation method, the temperature is usually about 200 to 300 ° C. and about 0.01 to 3 kPa. In the case of the steam distillation method, the temperature is about 200 to 300 ° C., and steam that is pressurized to about 0.1 to 1 MPa under normal pressure is blown into the reaction system. In the case of the extraction method, the rosin is used as an alkaline aqueous solution, unsaponifiable matter not dissolved in the aqueous solution is extracted with various organic solvents, and the remaining aqueous layer is neutralized. In the recrystallization method, the rosins are dissolved in an organic solvent as a good solvent, and then the organic solvent is distilled off to form a concentrated solution. Further, an organic solvent as a poor solvent is added to achieve the desired purification. Rosin is obtained. Organic solvents include aromatic hydrocarbons such as benzene, toluene and xylene; ketones such as acetone and methyl ethyl ketone; aliphatic hydrocarbons such as n-hexane, n-heptane and isooctane; alicyclic rings such as cyclohexane and decalin Group hydrocarbons and the like.

  The Diels-Alder reaction product is obtained by reacting the α, β unsaturated dicarboxylic acids and rosins under conditions of usually about 180 to 240 ° C. and about 1 to 9 hours. The amount used of both may be appropriately determined in consideration of the content of the component (a-1) in the component (A). Usually, α, The β unsaturated dicarboxylic acids are usually in the range of about 30 to 100 mol%, preferably 55 to 70 mol%. In order to suppress coloring of the target Diels-Alder reactant and to improve the color tone of the flux residue film, it is preferable to purge the reaction vessel with an inert gas stream such as nitrogen. In the reaction, various known catalysts, for example, Lewis acids such as zinc chloride, iron chloride and tin chloride, and Bronsted acids such as para-toluenesulfonic acid and methanesulfonic acid can be used. It is usually about 0.01 to 10% by weight based on rosins.

  The component (A) is obtained by hydrogenating the obtained Diels-Alder reactant by various known methods. Specifically, the Diels-Alder reactant is usually about 1 to 25 MPa (preferably 5 to 20 MPa) at a temperature of about 100 to 300 ° C. (preferably 150 to 260 ° C.) in the presence of a hydrogenation catalyst. What is necessary is just to make a hydrogenation reaction under hydrogen pressure. Examples of the hydrogenation catalyst include supported catalysts such as palladium carbon, rhodium carbon, ruthenium carbon, and platinum carbon, metal powders such as nickel and platinum, and iodides such as iodine and iron iodide. The amount of the hydrogenation catalyst used is usually about 0.01 to 10% by weight, preferably 0.1 to 5% by weight, based on the Diels-Alder reactant. If necessary, the organic solvent can be used as a reaction solvent. In addition, it is preferable to further refine | purify (A) component from an above-mentioned refinement | purification means from viewpoints, such as flux scattering prevention.

  The component (A) has a melt viscosity of usually about 100 to 1000 mPa · s / 180 ° C., preferably 200 to 600 mPa · s / 180 ° C. from the viewpoint of heating dripping, flux scattering, crack resistance of the flux residue, and the like. The melt viscosity can be adjusted by, for example, the content of the component (a-1) in the component (A). The “melt viscosity” refers to a value measured by a B-type viscometer in a state where the component (A) is melted at 180 ° C.

  The content of the component (a-1) in the component (A) is usually 30% by weight or more, preferably 40 to 75% by weight in consideration of heat dripping resistance, flux scattering suppression, flux residue crack resistance, and the like. Degree. Further, the component (A) may contain other resin acid, for example, dehydroabietic acid (hereinafter sometimes referred to as component (a-2)), and the content thereof is usually 70% by weight. Less, preferably about 10 to 25% by weight. Examples of the resin acid other than the components (a-1) and (a-2) include abietic acid and maleopimaric acid, and the content thereof is usually less than 70% by weight, preferably less than 50% by weight. It is.

  Component (A) may contain low molecular weight components (hereinafter simply referred to as low molecular weight components) having a molecular weight of 280 or less, such as various catalysts and impurities derived from raw material rosins. The amount is usually 3% by weight or less from the viewpoint of resistance to heat dripping and suppression of flux scattering.

  The content of various resin acids and low molecular weight components in the component (A) can be specified by various known analysis methods such as gel permeation chromatography (GPC) and gas chromatography (GC). For example, in the case of GPC, the resin acid content (X wt%) can be obtained by the following formula.

  X = [(Area of peak attributed to resin acid to be measured) / (Peak area of the entire resin acid component including the resin acid)] × 100

  Further, the structure of the component (a-1) in the component (A) and other resin acids can be identified by various known means such as IR method and NMR method.

  Although the other physical property of (A) component is not specifically limited, For example, the theoretical acid value based on a tertiary carboxyl group is about 130-160 mgKOH / g normally, Preferably it is 134-154 mgKOH / g. By using the component (A) having the theoretical acid value, effects such as suppression of heating dripping, suppression of flux scattering, and crack resistance of the flux residue film can be obtained in a balanced manner. The “theoretical acid value based on tertiary carboxyl group” is a calculated value expressed in mg of potassium hydroxide that reacts with a tertiary carboxyl group derived from various resin acids in component (A) in an equivalent amount. is there.

The component (A) has a molar concentration based on carboxyl groups (hereinafter referred to as unit carboxyl group molar concentration) of usually about 2.2 × 10 ^{−3 to} 3.2 × 10 ⁻³ mol / g, preferably 2. 4 × ¹⁰ -3 is good is a ~3 × ¹⁰ -3 mol / g. The unit carboxyl group concentration means the number of moles of carboxyl group (-COOH) per 1 g of component (A) (in terms of solid content), and by using such component (A), suppression of heat dripping and flux scattering are suppressed. In addition, effects such as crack resistance of the flux residue film can be obtained in a well-balanced manner. The unit carboxyl group concentration is an actual measurement value and is determined as follows.

  Unit carboxyl group molar concentration (mol / g) = Y− (YZ) × 2

(Calculation method of Y)
(A) 0.3 g of component is dissolved in 50 ml of acetone to prepare an acetone solution. Next, 25 ml of an aqueous potassium hydroxide solution (concentration 1.0 × 10 ⁻⁴ mol / ml; manufactured by Wako Pure Chemical Industries, Ltd., volumetric analysis reagent) is added to the acetone solution, and the mixture is stirred and left for 10 minutes. Next, several drops of phenolphthalein are added to the acetone solution after standing, neutralization titration is performed using an aqueous hydrochloric acid solution (concentration: 1.0 × 10 ⁻⁴ mol / ml), and the equivalence point (from red purple to colorless) Record the titer (ml) at the point of change). Then, Y is calculated from the following formula 1.

Formula 1: Y (mol / g) = {[(potassium hydroxide aqueous solution amount (ml) −hydrochloric acid titration amount (ml)] × potassium hydroxide aqueous solution concentration (mol / ml)} ÷ (A) component usage amount (g )

(Calculation method of Z)
Ethanol and toluene are mixed at a weight ratio = 1: 2 to prepare an ethanol / toluene solvent. Next, 1 g of the component (A) is dissolved in the ethanol / toluene solvent to prepare a toluene-ethanol solution of the component (A). Next, several drops of phenolphthalein solution are added to the solution, and an ethanolic potassium hydroxide solution (concentration 5.0 × 10 ⁻⁴ mol / ml; manufactured by Wako Pure Chemical Industries, Ltd., volumetric analysis reagent) is used. Titrate and record titration (ml) at the equivalence point (the point at which the solution changed from colorless to reddish purple). Then, Z is calculated from the following formula 2.

Formula 2: Z (mol / g) = [ethanolic potassium hydroxide solution titration (ml) × ethanolic potassium hydroxide solution concentration (mol / ml)] ÷ (A) component usage (g)

  In addition, from the viewpoints of heat dripping resistance, flux scattering suppression, flux residue crack resistance, and the like, the softening point of component (A) (refers to the value measured by the ring and ball method defined in JIS K 59202; the same applies hereinafter). Is usually about 100 to 150 ° C, preferably 110 to 130 ° C.

  In particular, from the viewpoint of the color tone of the flux residue, the color tone of the component (A) is usually Gardner 2 or less, preferably Gardner 1 or less to Hazen 50 or so. (Hazen color tone is a value measured according to JIS K 0071-1, and Gardner color tone is a value measured according to JIS K 0071-2.)

  In addition to the component (A), the flux of the present invention includes a thixotropic agent (B) (hereinafter referred to as component (B)), a flux solvent (C) (hereinafter referred to as component (C)), and as necessary. Accordingly, the base material (E) other than the component (A) (E) (hereinafter referred to as component (E)) and various additives (F) (hereinafter referred to as component (F)) are included.

  Examples of the component (B) include animal and plant thixotropic agents such as hardened castor oil, beeswax and carnauba wax, and amide thixotropic agents such as stearic acid amide and hydroxystearic acid ethylenebisamide. Or in combination of two or more.

  As the component (C), for example, alkylene glycol monoethers such as diethylene glycol monohexyl ether and diethylene glycol monobutyl ether; hexyl glycol, octanediol, ethylhexyl glycol, benzyl alcohol, 1,3-butanediol, 1,4-butanediol, Other alcohols such as 2- (2-n-butoxyethoxy) ethanol, terpineol; esters such as butyl benzoate, diethyl adipate, dioctyl sebacate, 2- (2-n-butoxyethoxy) ethyl acetate; dodecane , Hydrocarbons such as tetradecene; pyrrolidones such as N-methyl-2-pyrrolidone, and the like can be used singly or in combination of two or more. Among these, the alkylene glycol monoethers and / or esters are preferable. In particular, considering the soldering temperature, the component (C) having a boiling point in the range of about 150 to 300 ° C., preferably 220 to 270 ° C. (particularly alkylene glycol monoethers and / or esters) is preferable.

Examples of the component (D) include hydrohalates of amines such as ethylamine hydrobromide and cyclohexylamine hydrobromide; succinic acid, benzoic acid, adipic acid, glutaric acid, palmitic acid, stearic acid , Aliphatic organic carboxylic acids containing no halogen atom such as picolinic acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid, etc .; N, N′-bis (4-aminobutyl) -1,2-ethanediamine, tri Organic diamines such as ethylenetetramine, N, N ′-(3-aminopropyl) ethylenediamine, N, N′-bis (3-aminopropyl) piperazine; 3-bromopropionic acid, 2-bromovaleric acid, 5-bromo -N-valeric acid, 2-bromoisovaleric acid, 2,3-dibromosuccinic acid, 2-bromosuccinic acid, 2,2-dibromoadipic acid, etc. Dicarboxylic acids; 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- Bromodiols such as 2-butene-1,4-diol; Bromoalkanes such as 1,2,3,4-tetrabromobutane and 1,2-dibromo-1-phenylethane; 1-bromo-3-methyl Bromoalkenes such as -1-butene, 1,4-dibromobutene, 1-bromo-1-propene, 2,3-dibromopropene, 1,2-dibromostyrene; 4-stearo Luoxybenzyl bromide, 4-stearyloxybenzyl bromide, 4-stearylbenzyl bromide, 4-bromomethylbenzyl stearate, 4-stearoylaminobenzyl bromide, 2,4-bisbromomethylbenzyl stearate, 4-palmitoyloxy Examples thereof include benzyl bromide, 4-myristoyloxybenzyl bromide, 4-lauroyloxybenzyl bromide, 4-undecanoyloxybenzyl bromide and the like. The component (D) is preferably at least one selected from the group consisting of aliphatic organic carboxylic acids not containing halogen atoms, organic diamines, bromodicarboxylic acids, and bromodiols.
(I added.)

  Examples of the component (E) include the raw rosins, Diels-Alder reactants obtained from the raw rosins and α, β unsaturated monocarboxylic acids (acrylic acid, methacrylic acid, etc.), hydrides thereof, Raw material rosin hydrides, disproportionated rosin, formylated rosin, polymerized rosin, and other rosin base materials other than component (A), epoxy resin, acrylic resin, polyimide resin, polyamide resin (nylon resin), Examples thereof include synthetic resins such as polyester resin, polyacrylonitrile resin, vinyl chloride resin, vinyl acetate resin, polyolefin resin, fluorine resin, and ABS resin, and these can be used alone or in combination of two or more.

  Examples of the component (F) include additives such as antioxidants, antifungal agents, and matting agents.

Although the usage-amount of (A) component-(D) component is not specifically limited, when the heating dripping, flux scattering, the crack resistance of a flux residue film | membrane, etc. are considered, it is as follows normally. (However, the total does not exceed 100% by weight.)
Component (A): about 30 to 75% by weight, preferably 40 to 55% by weight
Component (B): about 0.1 to 10% by weight, preferably 3 to 10% by weight
Component (C): about 20 to 69.9% by weight, preferably 30 to 56.9% by weight
Component (D): about 0 to 10% by weight, preferably 0.1 to 5% by weight

In addition, although the usage-amount of the (E) component and (F) component in the flux of this invention is not specifically limited, Usually, it is as follows.
(E) component: less than about 30% by weight, preferably less than 25% by weight (F) component: less than 10% by weight, preferably less than 5% by weight

  The solder paste of the present invention is obtained by mixing the flux of the present invention and solder powder by various known means (planetary mill, etc.), and the amounts used are usually about 5 to 20 parts by weight and 80 to 95 parts by weight, respectively. Degree.

  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 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- Lead-free solder powders such as S-based solder powder and Sn-Ag-Cu-Ni-Ge solder powder are exemplified. Note that the flux according to the present invention suitably works even at the melting temperature of lead-free solder, and can suppress heating dripping, generation of solder balls, cracks in the flux residue, etc. As a solder powder, lead-free solder powder In particular, Sn-based lead-free solder powder is preferable.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not limited to these Examples.

  In each of the preparation examples, “melt viscosity” is a value obtained by using a commercially available B8M type viscometer (product name “VISCOMETER”, manufactured by TOKIMEC, rotor No. HM-1), “maleopimaric anhydrides”. "Content of low molecular weight component" is a commercially available gel permeation chromatography measuring device (product name "High Speed GPC System HLC-8220", manufactured by Tosoh Corporation, column name "TSK-GEL G1000HXL" “Dehydroabietic acid content” means a value calculated with a commercially available gas chromatographic apparatus (product name “GC7890”, manufactured by Agilent). .

<Preparation of component (A)>
Preparation Example 1
Step (1): Purification Unpurified gum rosin (measured acid value: 171 mg KOH / g, unit carboxyl group molar concentration: 3.2 × 10 ⁻³ mol / g, softening point: 74 ° C., Gardner 6, manufactured in China) in a vacuum distillation vessel Preparation and distillation under reduced pressure of 0.4 kPa under a nitrogen seal gave purified rosin (actual acid value 177, softening point 80 ° C., Gardner 3).

Step (2): Diels-Alder Reaction Next, 700 g of the purified rosin and 154 g of maleic anhydride were charged into another vacuum distillation vessel and reacted at 220 ° C. for 4 hours with stirring in a nitrogen stream, followed by 4 kPa under reduced pressure. The rosin derivative (theoretical acid value 144 mgKOH / g, unit carboxyl group molar concentration 2.7 × 10 ⁻³ mol / g, softening point 121 ° C., Gardner 8) was obtained by removing unreacted product.

Step (3): Hydrogenation Reaction Next, 500 g of the rosin derivative and 6.0 g of 5% palladium carbon (water content: 50%) were charged into a 1 liter rotary autoclave to remove oxygen in the system, and then 10 MPa with hydrogen. The rosin derivative hydride (theoretical acid value 144 mgKOH / g, unit carboxyl group molar concentration 2.7 × 10 ⁻³ mol / g) was heated to 220 ° C. and hydrogenated at the same temperature for 3 hours. A softening point of 120 ° C.).

Step (4): Purification Next, 400 g of the rosin derivative hydride and 200 g of xylene were charged into a reaction vessel and dissolved under heating, and then 150 g of xylene was distilled off. Next, 150 g of cyclohexane was charged and cooled to room temperature. When the crystal yield reached about 40 g, the supernatant was transferred to another reaction vessel and recrystallized at room temperature. Then, after further removing the supernatant and washing with 20 g of cyclohexane, the cyclohexane was distilled off to obtain a melt viscosity of 361 mPa · s (180 ° C.), a theoretical acid value of 144 mgKOH / g, and a unit carboxyl group molar concentration of 2.7. × 10 ⁻³ mol / g, softening point 120 ° C., Hazen color 150, maleopimaric anhydride (a-1) content is about 66% by weight, dehydroabietic acid (a-2) content is about 17 A rosin derivative hydride (A-1) (hereinafter referred to as component (A-1)) having a weight percent of 0.7% by weight and a low molecular weight component was obtained. Table 1 shows the physical properties and the like.

Preparation Example 2
A rosin derivative hydride (A-2) (hereinafter referred to as component (A-2)) was obtained in the same manner as in Preparation Example 1 except that 154 g of maleic anhydride was changed to 77 g. Table 1 shows the physical properties and the like.

Preparation Example 3
In the same manner as in Preparation Example 1, except that 6.0 g of 5% palladium carbon (water content 50%) was changed to 12.0 g, rosin derivative hydride (A-3) (hereinafter referred to as (A- 3) Component)) was obtained. Table 1 shows the physical properties and the like.

Preparation Example 4
In the same manner as in Step (3) of Preparation Example 2, except that 6.0 g of 5% palladium carbon (water content 50%) was changed to 12.0 g, rosin derivative hydride (A-4) (hereinafter referred to as (A- 4) Component)) was obtained. Table 1 shows the physical properties and the like.

Preparation Example 5
A rosin derivative hydride (A-5) (hereinafter referred to as component (A-5)) was obtained in the same manner except that 154 g of maleic anhydride was changed to 200 g in the step (2) of Preparation Example 1. Table 1 shows the physical properties and the like.

Preparation Example 6
In the same manner as in Step 5 of Preparation Example 5 except that 6.0 g of 5% palladium carbon (water content 50%) was changed to 12.0 g, rosin derivative hydride (A-6) (hereinafter referred to as (A- 6) Component)) was obtained. Table 1 shows the physical properties and the like.

Preparation Example 7
The rosin derivative hydride (A-7) (hereinafter referred to as (A-7) component) was used in the same manner except that unpurified gum rosin was used in step (2) without purification in step (1) of Preparation Example 1. ) Table 1 shows the physical properties and the like.

Comparative Preparation Example 1
A rosin derivative hydride (X-1) (hereinafter referred to as component (X-1)) was obtained in the same manner except that 105 g of acrylic acid was used instead of 154 g of maleic anhydride in the step (2) of Preparation Example 1. It was. Table 1 shows the physical properties of the component (X-1).

<Preparation of flux>
Example 1
Flux by adding 50 parts of (A-1) component, 5 parts of 12-hydroxystearic acid ethylenebisamide as component (B), and 45 parts of diethylene glycol monohexyl ether as component (C), and dissolving by heating. Was prepared.

Example 2
A flux was prepared in the same manner as in Example 1 except that the component (A-2) was used instead of the component (A-1).

Example 3
In Example 1, a flux was prepared in the same manner except that the component (A-3) was used instead of the component (A-1).

Example 4
A flux was prepared in the same manner as in Example 1 except that the component (A-4) was used instead of the component (A-1).

Example 5
A flux was prepared in the same manner as in Example 1 except that the component (A-5) was used instead of the component (A-1).

Example 6
In Example 1, a flux was prepared in the same manner except that the component (A-6) was used instead of the component (A-1).

Example 7
A flux was prepared in the same manner as in Example 1 except that the component (A-7) was used instead of the component (A-1).

Example 8
A flux was prepared in the same manner as in Example 1 except that 17-hydroxystearic acid ethylene bisamide was used instead of 12-hydroxystearic acid ethylene bisamide as component (B).

Example 9
In Example 1, a flux was prepared in the same manner except that hydrogenated castor oil was used in place of 12-hydroxystearic acid ethylenebisamide as component (B).

Example 10
The flux obtained in Example 1 was further mixed with 5 parts of adipic acid as component (D) to prepare a flux.

Example 11
The flux obtained in Example 1 was further mixed with 1 part of trans 2,3-dibromo-1,4-butanediol as component (D) to prepare a flux.

Example 12
In Example 1, a flux was prepared in the same manner except that 3 parts of N, N-bis (3-aminopropyl) ethylenediamine was used as the component (D).

Comparative Example 1
In Example 1, a flux was prepared in the same manner except that the component (X-1) was used instead of the component (A-1).

Comparative Example 2
In Example 1, it replaced with (A-1) component except having used the commercially available hydrogenated rosin (Arakawa Chemical Industries Co., Ltd. product, "Hyper CH", hereafter, referred to as (X-2) component). Thus, a flux was prepared. The physical properties of the component (X-2) are shown in Table 1.

Comparative Example 3
In Example 1, the flux was changed in the same manner as in Example 1 except that the purified rosin obtained in step (1) of Preparation Example 1 (hereinafter referred to as (X-3) component) was used instead of the component (A-1). Prepared. In addition, Table 1 shows the physical properties and the like of the component (X-3).

Comparative Example 4
In Example 1, a flux was prepared in the same manner except that the rosin derivative obtained in Step (2) of Preparation Example 1 (hereinafter referred to as (X-4) component) was used instead of the component (A-1). did. In addition, Table 1 shows the physical properties of the component (X-4).

Comparative Example 5
In Example 1, instead of the component (A-1), a commercially available disproportionated rosin (Arakawa Chemical Industries, “Longis R”; undistilled, unhydrogenated, hereinafter referred to as the component (X-5) ) Was used in the same manner except that the above was used. In addition, Table 1 shows the physical properties of the component (X-5).

Comparative Example 6
In Example 1, instead of the component (A-1), a commercially available polymerized rosin (Arakawa Chemical Industries, Ltd., “Aradim R-140”; undistilled, unhydrogenated, hereinafter referred to as the component (X-6) ) Was used in the same manner except that the above was used. In addition, Table 1 shows the physical properties and the like of the component (X-6).

Comparative Example 7
In Example 1, instead of the component (A-1), a commercially available gum rosin (Arakawa Chemical Industries, “CG-WW”; undistilled, unhydrogenated, hereinafter referred to as the component (X-7)) was used. A flux was prepared in the same manner except that it was used. In addition, Table 1 shows the physical properties and the like of the component (X-7).

In Table 1, each symbol has the following meaning.
H: Hazen color G: Gardner color 12-HSBA: 12-hydroxystearic acid ethylene bisamide 17-HSBA: 17-hydroxystearic acid ethylene bisamide C-WAX: hardened castor oil DEGMHE: diethylene glycol monohexyl ether AA: adipic acid DBBD: trans 2,3 Dibromo-1,4-butanediol BAPED: N, N-bis (3-aminopropyl) ethylenediamine None of the components (X-3) to (X-7) is a hydride.
Moreover, the unit carboxyl group molar concentration of the component (X-1) to the component (X-7) is an actual measurement value obtained in accordance with the method described in paragraphs [0032] to [0036] of the present specification.

Comparative Example 8
In Example 1, instead of 50 parts of component (A-1), a mixture of 45 parts of component (X-1) and 5 parts of hydride of alcohol-modified dicyclopentadiene resin (softening point 120 ° C., color tone H200, trade name) A flux was prepared in the same manner except that “KR-1842” (manufactured by Arakawa Chemical Industries, Ltd., hereinafter referred to as “component (X-8)”) was used.

(Preparation of solder paste)
10 parts of the flux of Example 1 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) are stirred in a beaker. A solder paste was prepared. Solder pastes were similarly prepared for the fluxes of Examples 2 to 12 and Comparative Examples 1 to 8.

<Performance evaluation>

(Heating test)
On the copper substrate, the solder paste according to Example 1 was screen-printed in a vertical row so as to be at a predetermined interval in accordance with “JIS Z3284 Annex 8 Sagging test during heating”. Heating was performed for 160 seconds in a reflow furnace (preheating condition: 100 ° C. at 180 ° C., main heating condition: approximately 60 seconds at 240 ° C.), and the degree of heating was confirmed by visually confirming the change in the shape of the solder paste. The solder pastes according to Examples 2 to 12 and Comparative Examples 1 to 8 were similarly evaluated.
4: Very difficult to droop; non-integral spacing less than 0.6 mm 3: Difficult to snag; non-integral spacing of 0.6 mm to less than 0.7 mm 2: Slightly prone; non-integral spacing of 0.7 mm or more Less than ~ 0.8mm 1: Easy to droop; Non-integral spacing is 0.8mm or more

(Solderability)
For each of the solder pastes of Examples 1 to 12 and Comparative Examples 1 to 8, the solderability (wetability) was evaluated in accordance with “JIS Z3284 Annex 10 Wetting Efficacy and Dewetting Test”. (Expansion degree category 1 or 2). In Tables 2 and 3, it is indicated as “3”.

(Flux scattering, solder balls, cracks, color tone)
On the copper substrate, the solder paste according to Example 1 was screen-printed, and the soldered part was observed with a microscope VW-6000 (manufactured by Keyence Corporation: 30 times), thereby causing the degree of flux scattering and generation of solder balls. The presence or absence of cracks in the flux residue and the color tone of the flux residue were visually determined according to the following criteria. The generation of solder balls conformed to “JIS Z3284 Annex 11 Solder ball test”. The solder pastes according to Examples 2 to 12 and Comparative Examples 1 to 8 were similarly evaluated.

3: No scattering 2: Slight scattering is observed 1: Many scattering is observed

2: Good; less than 10 solder balls 1: Bad; 10 or more solder balls

3: No crack 2: Slight cracks are observed 1: Many cracks are observed

3: Colorless and transparent 2: Slightly colored 1: Colored

  From Examples 1 to 7, since the flux of the present invention uses a hydride of a rosin derivative mainly composed of maleopimaric anhydride as a base material, good results can be obtained in any evaluation. ing. On the other hand, as in Comparative Example 1 (acrylic acid-modified rosin hydride) and Comparative Example 2 (hydrogenated rosin), rosin derivatives and rosins that do not contain maleopimaric anhydride are heated and fluxed even if they are hydrides. It turns out that it is inferior in scattering, the crack resistance of a flux residue, and a color tone.

  From Examples 8 to 12, it can be seen that the flux of the present invention uses the component (A), so that good results are obtained even when other flux materials are changed.

  Comparative Example 3 (unhydrogenated purified rosin), Comparative Example 4 (unhydrogenated maleic anhydride modified rosin), Comparative Example 5 (disproportionated rosin), Comparative Example 6 (polymerized rosin), and Comparative Example 7 ( From the results of Gum rosin), it is found that for these rosin base materials, it is difficult to achieve both suppression of heating dripping and prevention of flux scattering if they are not hydrogenated, and may be inferior in other performances. .

  From the results of Comparative Example 8, it can be seen that if a part of the rosin-based base material is replaced with a petroleum resin-based base material, heating drooling is slightly improved, but residual cracks are likely to occur.

Claims (15)

Soldering using a rosin derivative hydride (A) containing maleopimaric anhydrides (a-1) represented by the following structural formula (1) and having a melt viscosity of 100 to 1000 mPa · s / 180 ° C. Rosin flux for use.

(In formula (1), the broken line means that a carbon-carbon bond may exist there.) The rosin-based flux for soldering according to claim 1, wherein the content of the component (a-1) in the component (A) is 30% by weight or more. The soldering rosin flux according to claim 2, wherein the component (A) further contains less than 70% by weight of dehydroabietic acid (a-2). The soldering rosin-based flux according to any one of claims 1 to 3, wherein the content of the low molecular weight component having a molecular weight of 280 or less in the component (A) is 3 wt% or less. The soldering rosin-based flux according to any one of claims 1 to 4, wherein the carboxyl group molar concentration of the component (A) is 2.2 × 10 ^{−3 to} 3.2 × 10 ⁻³ mol / g. The soldering rosin flux according to any one of claims 1 to 5, wherein the softening point of the component (A) is 100 to 150 ° C. The soldered rosin-based flux according to claim 1, wherein the (A) component has a Gardner color tone of 2 or less. The soldered rosin-based flux according to any one of claims 1 to 7, further comprising a thixotropic agent (B), a flux solvent (C), and an activator (D). The soldering rosin flux according to claim 8, wherein the component (B) is an animal or plant thixotropic agent and / or an amide thixotropic agent. The soldering rosin-based flux according to claim 8 or 9, wherein the component (C) is an alkylene glycol monoether having a boiling point of 150 to 300 ° C and / or an ester having a boiling point of 150 to 300 ° C. The activator (D) is at least one selected from the group consisting of aliphatic organic carboxylic acids not containing a halogen atom, organic diamines, bromodicarboxylic acids, and bromodiols. Rosin flux for soldering. The rosin-based flux for soldering according to any one of claims 8 to 11, comprising the components (A) to (D) in the following weight percents.
(A) component: 30 to 75% by weight
(B) component: 0.1 to 10% by weight
Component (C): 20 to 69.9% by weight
(D) component: 0 to 10% by weight A solder paste containing the rosin flux for soldering according to claim 1 and solder powder. The solder paste according to claim 13, wherein the solder powder is lead-free solder powder. The solder paste according to claim 14, wherein the lead-free solder powder is Sn-based lead-free solder powder.