WO2009090798A1

WO2009090798A1 - Flux creeping-up preventive composition for solder, electronic member for solder coated with the composition, method for soldering the member, and electrical appliance

Info

Publication number: WO2009090798A1
Application number: PCT/JP2008/071320
Authority: WO
Inventors: Ryo Hirabayashi; Fusae Ishiwata
Original assignee: Agc Seimi Chemical Co., Ltd.
Priority date: 2008-01-18
Filing date: 2008-11-25
Publication date: 2009-07-23
Also published as: CN101952082B; CN101952082A; JP5295131B2; MY150334A; JPWO2009090798A1

Abstract

Disclosed is a flux creeping-up preventive composition for a solder that has flux creeping-up preventive properties comparable with those of a conventional flux creeping-up preventive agent comprising a polymer containing a polyfluoroalkyl group having 8 or more carbon atoms, wherein an influence on a living body and an environment can be significantly reduced. The flux creeping-up preventive composition comprises a polymer comprising at least one type of an (meth)acrylate polymerization unit (A) containing a perfluoroalkyl group having 6 or less carbon atoms and at least one type of a polymerization unit (B) derived from a hydroxyl group-containing unsaturated compound. The polymer has a weight average molecular weight (in terms of polymethyl methacrylate) of not less than 150000.

Description

Solder flux creeping-up composition, electronic member for solder coated with the composition, method for soldering the member, and electrical product

The present invention relates to a flux creeping-up preventing composition used as a pretreatment agent for preventing solder flux from creeping up when soldering an electronic component having electrical contacts or an electronic member such as a printed circuit board. The present invention also relates to an electronic component such as an electronic component for soldering or a printed board having a coating formed from the composition, a soldering method using the composition, and an electric product including the soldered electronic component. .

When soldering various parts to a printed circuit board or soldering an IC to an IC socket, a flux treatment for improving the adhesiveness of the solder is performed in advance. A general flux is a corrosive agent containing an acidic component in a solvent. For this reason, it is undesirable for flux to penetrate or adhere to electrical contact parts of electronic parts such as connectors, switches, volumes, semi-fixed resistors, or parts that do not require soldering on printed circuit boards, and this must be prevented. . In particular, due to the phenomenon called “flux scooping up” that occurs in the through-hole part of electronic parts due to the capillary phenomenon, the flux adheres to or penetrates into parts that are not soldered, causing corrosion. Need to prevent.

For this reason, prior to soldering, pre-treatment is performed to prevent flux creeping. The flux creep-up preventing agent used for this pretreatment is usually a composition containing a polymer having a solvent repellency with respect to the solvent of the flux. Conventionally, since the flux solvent is typically IPA, IPA repellency has been used as an index of the flux creep-up prevention performance. Therefore, a polyfluoroalkyl group-containing polymer having high IPA repellency has been used as an active ingredient of the flux creeping-up preventing agent.

Conventionally, such a polymer is typically CH ₂ ═C (R ¹ ) COO—QR ^f (wherein R ^{1 is a} hydrogen atom or a methyl group, Q is a divalent linking group, R ^{f is} A polymer derived from a (meth) acrylate having a polyfluoroalkyl group represented by (C4-14 polyfluoroalkyl group) (see Patent Document 1).

JP-A-10-303536

The US Environmental Protection Agency (USEPA) published a preliminary risk study report on the safety of perfluorooctanoic acid (PFOA) detected in various environments, including wild animals and human blood, in March 2003. Furthermore, in January 2006, PFOA and its related substances and their precursor substances were proposed to fluororesin manufacturers and others to participate in a reduction plan in the environment and content reduction in products. When the carbon number of the perfluoroalkyl group is 6 or less, the risk to living bodies and the environment is greatly reduced.

However, the performance such as hydrophobicity and oleophobicity resulting from the perfluoroalkyl group in the polymer is high when the carbon number of the perfluoroalkyl group is 8 or more, but is remarkably lowered when the carbon number is 6 or less. To do. This is said to be because a perfluoroalkyl group having 8 or more carbon atoms has crystallinity. The IPA repellency, which is important as an index of the performance of the flux creeping-up preventing agent, also decreases rapidly when the carbon number of the perfluoroalkyl group is 6 or less. Especially when the immersion treatment is performed at a low concentration, the performance degradation is very large.

Furthermore, the flux creeping-up preventing agent is required to be a very thin film in order to prevent contact failure due to the flux creeping-up preventing film processed on the contact part of the electronic component. When the immersion treatment is performed, IPA performance at a very low concentration is required.

The present invention is a polymer containing a polymer unit derived from an unsaturated compound having a polyfluoroalkyl group having 6 or less carbon atoms, which has little influence on the living body and the environment. Of a flux scooping prevention composition for a solder having a performance equivalent to that of a flux scooping prevention agent comprising a polymer containing a polymer unit derived from an unsaturated compound having a molecular weight of 8 or more and having a high flux scooping prevention performance With the goal.

In view of the above problems, the present invention is a polymer containing a polymer unit derived from an unsaturated compound having a polyfluoroalkyl group having 6 or less carbon atoms, which has little influence on the living body and the environment. By introducing a polar group into the polymer and setting the weight average molecular weight of the polymer to 150,000 or more, a polymer unit derived from an unsaturated compound having 8 or more carbon atoms in a conventional polyfluoroalkyl group is obtained. The present invention makes it possible to provide a flux scooping preventive agent having the same performance as the flux scooping preventive agent containing the polymer contained.

The solder flux creeping-up composition according to the present invention comprises a polymerization unit (A) derived from a compound represented by the following formula (a) and a polymerization unit (B) derived from an unsaturated compound containing a hydroxyl group. Each polymer contains at least one polymer and has a weight average molecular weight (in terms of polymethyl methacrylate) of 150,000 or more.
CH ₂ ═C (R ¹ ) —C (O) OQ ¹ —R ^f (a)
In the formula, R ¹ : a hydrogen atom or a methyl group,
Q ¹ : a single bond or a divalent linking group,
R ^f represents a polyfluoroalkyl group or polyfluoroether group having a main chain length of 1 to 6 carbon atoms.

In the above formula (a), a preferred R ^f group is a linear perfluoroalkyl group or perfluoroether group having 1 to 6 carbon atoms.
In Formula (a), Q ¹ is preferably a single bond or a linear alkylene group having 1 to 6 carbon atoms, an amino group, a sulfonyl group, or a combination thereof.

The polymerization unit (B) is preferably derived from a compound represented by the following formula (b).
CH ₂ ═C (R ¹ ) —C (O) O—Q ² —OH (b)
Wherein, ^{R 1:} same as in the formula ^{(a), Q} 2: 2 divalent linking group.

An embodiment in which the proportion of the polymer units (B) in the polymer is 10% by mass or less is preferable.
The solder flux creeping-up composition according to the present invention is usually in a liquid form, and preferably contains a polymer as described above at a concentration of 0.001 to 10% by mass.

Another aspect of the present invention is an electronic member that has a coating made of any of the above-described compositions on part or all of the soldering portion of the electronic member and has a solder flux creeping-up preventing performance.

The present invention also provides a method of forming a film made of any of the above-described compositions on a part or all of a part to be soldered of an electronic member, applying a part or all of the film with a soldering flux, A method of soldering an electronic member to be attached is provided, and an electric product including the electronic member soldered by the method is also provided.

The present invention provides a composition for preventing flux creep-up, not only by suppressing the content of polyfluoroalkyl groups having 8 or more carbon atoms in the polymer to ensure safety to living bodies and the environment, but also to polyfluoroalkyl. Suppression of the creeping prevention performance due to the decrease in the chain length of the group is suppressed, and it is possible to maintain the same level of performance as conventional products.
The flux scooping prevention composition of the present invention has the same contact resistance and solder wettability as the film formed thereby, so that even if a film is formed on an electronic component or the like, the contact portion Is less likely to cause contact failure due to the coating, and it is considered that the soldering of the coating forming portion is less likely to cause trouble.

In addition, in this specification, (meth) acrylate represents both or one of acrylic ester and methacrylic ester.

The polymer contained in the composition for preventing creeping up of the solder flux of the present invention (also referred to as “scooping-up preventing agent”) is a polymer unit (A) derived from a compound represented by the following formula (a): And at least one polymerization unit (B) derived from an unsaturated compound containing a hydroxyl group.
CH ₂ ═C (R ¹ ) —COO—Q ¹ —R ^f (a)
However, the symbols in the formulas have the following meanings.
R ¹ : a hydrogen atom or a methyl group,
Q ¹ : a single bond or a divalent linking group,
R ^f : a polyfluoroalkyl group or polyfluoroether group having a main chain length of 1 to 6 carbon atoms.

The polyfluoroalkyl group means a partially fluoro-substituted or perfluoro-substituted alkyl group in which two to all of the hydrogen atoms of the alkyl group are substituted with fluorine atoms. The polyfluoroalkyl group represented by the R ^f group may have either a straight chain structure or a branched structure, but the main chain length (the number of carbon atoms not including the side chain) is an alkyl having 1 to 6 carbon atoms. A partially fluoro- or perfluoro-substituted alkyl group corresponding to the group. Specific examples include a moiety corresponding to an alkyl group such as methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, 3-methylbutyl or a perfluoro-substituted alkyl group.
The polyfluoroether group means a group in which an etheric oxygen atom is inserted between one or more carbon-carbon atoms in the polyfluoroalkyl group.

Among the above, the R ^f group preferably has a linear structure from the viewpoint of increasing the packing of the R ^f group. For the same reason, in the case of a branched structure, it is preferable that the branched portion is present at the terminal portion of the R ^f group.
The R ^f group is preferably a polyfluoroalkyl group. Further, the R ^f group is preferably a substantially perfluorinated perfluoroalkyl group (R ^F ), more preferably an R ^F group having a main chain length of 1 to 6 carbon atoms, It is particularly preferable that the R ^F group is.

Q ¹ is a single bond or a divalent linking group. Examples of the divalent linking group include, but are not limited to, —O—, —S—, —N (R) — (wherein R is H or an alkyl group having 1 to 3 carbon atoms), _{_{-SO 2 -, - PO 2 -}} , - CH = CH -, - CH = N -, - N = N -, - N (O) = N -, - COO -, - COS -, - CONH -, - COCH ₂ —, —CH ₂ NH—, —CH ₂ —, —CO—, —CH═CH—COO—, —CH═CH—CO—, a linear or branched alkylene group or alkenylene group, — ( An alkyleneoxy group such as CH ₂ CH ₂ O) _n —, — (CH ₂ CH ₂ CH ₂ O) _n — (where n is an integer of 1 to 30), divalent 4, 5, 6 or 7 members Ring substituents, condensed substituents composed thereof, 6-membered aromatic groups such as phenylene, 4- to 6-membered saturated saturated groups The unsaturated aliphatic groups, 5- or 6-membered heterocyclic group or include their condensed rings. Moreover, the group comprised from the combination of these bivalent coupling groups is mentioned.

The above linking group may have a substituent. Examples of the substituent include a halogen atom (F, Cl, Br, I), a hydroxyl group, a cyano group, an alkoxy group (methoxy, ethoxy, butoxy, octyl). Oxy, methoxyethoxy, etc.), aryloxy groups (phenoxy, etc.), alkylthio groups (methylthio, ethylthio, etc.), acyl groups (acetyl, propionyl, benzoyl, etc.), sulfonyl groups (methanesulfonyl, benzenesulfonyl, etc.), acyloxy groups (acetoxy, Benzoyloxy etc.), sulfonyloxy groups (methanesulfonyloxy, toluenesulfonyloxy etc.), phosphonyl groups (diethylphosphonyl etc.), amide groups (acetylamino, benzoylamino etc.), carbamoyl groups (N, N-dimethylcarbamoyl, N -Feni Carbamoyl etc.), alkyl groups (methyl, ethyl, propyl, isopropyl, cyclopropyl, butyl etc.), aryl groups (phenyl, toluyl etc.), heterocyclic groups (pyridyl, imidazolyl, furanyl etc.), alkenyl groups (vinyl, 1- Propenyl, etc.), alkoxyacyloxy groups (acetyloxy, etc.), alkoxycarbonyl groups (methoxycarbonyl, ethoxycarbonyl, etc.), and polymerizable groups (vinyl group, acryloyl group, methacryloyl group, silyl group, cinnamic acid residue, etc.) Can be mentioned.

Q ¹ can be appropriately selected as long as it is a single bond or a divalent linking group, but is a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms, a phenylene group, an amino group (—N ( R)-), a sulfonyl group (—SO ₂ —) and a divalent linking group selected from a combination thereof are preferable. Specific examples of the divalent linking group in this combination include —N (R) —SO ₂ —, the above alkylene group or phenylene group, and —NR—, —SO ₂ — or —N (R) —SO. Examples thereof include a linking group to _2- . The alkylene group is preferably linear.

Among the compounds represented by the formula (a), a preferable one is represented by the following formula (a1).
CH ₂ ═C (R ¹ ) —COO— (CH ₂ ) _p —R ^f (a1)
Where p is an integer from 0 to 6,
R ¹ and R ^f are the same as those in the formula (a).

Among these, compounds having a structure in which R ^f is a linear perfluoroalkyl group (R ^F ) having 1 to 6 carbon atoms are particularly suitable. Such compounds specifically include
CH ₂ ═CH—COO— (CH ₂ ) ₂ —C ₆ F ₁₃ ,
CH ₂ ═C (CH ₃ ) —COO— (CH ₂ ) ₂ —C ₆ F ₁₃ ,
_{_{CH 2 = CH-COO- (CH}} 2) 2 -C 4 F 9,
CH ₂ ═C (CH ₃ ) —COO— (CH ₂ ) ₂ —C ₄ F ₉
Etc.

The polymerization unit (B) is derived from an unsaturated compound containing a hydroxyl group. This compound is preferably a compound represented by the following formula (b).
CH ₂ ═C (R ¹ ) —C (O) O—Q ² —OH (b)
In the formula, R ¹ is the same as defined in formula (a), and Q ² is a divalent linking group.
Q ² can be appropriately selected as long as it is a divalent linking group, and examples thereof include, but are not limited to, those similar to Q ¹ in formula (a).

Among these, a compound represented by the following formula (b1) is preferable.
CH ₂ ═C (R ¹ ) —C (O) O—Q ³ —OH (b1)
In the formula, R ¹ is the same as defined above, and Q ³ represents an alkylene group, a phenylene group, a cyclohexylene group, an ester bond, an amide bond, — (CH ₂ CH ₂ O) _n —, — (CH ₂ CH ₂ CH ₂ O) _n- , or a combination thereof (where n is an integer from 1 to 30). These groups may have a substituent such as a hydroxyl group or an aryl group. Specific examples of Q ³ shown in Table 1. Ph is a phenyl group.

N = 1 to 10 in Table 1 above

The polymer according to the present invention is a copolymer containing at least one of the above polymerized units (A) and polymerized units (B), and the polymerized units (B) are represented by the formula (b). It is preferable that the polymerization unit (A) is derived from the compound represented by the formula (a1) and the polymerization unit (B) is derived from the compound represented by the formula (b1). It is more preferable that they are used.

The content of polymer units (A) in the polymer is preferably 90% by mass or more, and more preferably 95% by mass or more. When the content of the polymerization unit (A) is 90% by mass or more, the IPA performance can be maintained and the creeping prevention performance can be maintained.

The content of the polymer units (B) in the polymer is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass. When the content is within the above range, the IPA performance of the copolymer is improved, and good anti-cracking performance of the flux can be obtained. When the content is too small, the creeping prevention performance is low, and when the content is too large, the solubility of the copolymer in the solvent is remarkably lowered.
In the polymer according to the present invention, the content of each polymerization unit can be substantially regarded as a polymerization charge amount. In the polymerization unit (A) or (B), when the polymerization unit is composed of two or more kinds, the content is the total of the respective polymerization units.

The polymer according to the present invention may contain other polymer units (C) in addition to the polymer units (A) and (B) as described above. The other polymerization unit (C) is not particularly limited as long as it is a polymerization unit derived from a compound that can be copolymerized with the compounds forming the above (A) and (B). Examples of this compound include a compound (c) having a polymerizable group. Specifically, (meth) other than the compounds exemplified for the styrene compound (c1) and the polymerized units (A) and (B). Examples thereof include a compound (c) having an unsaturated group such as an acrylic acid compound (c2) and a further polymerizable compound (c3). Although the specific example of such a compound (c) is shown below, it is not limited to these.

As said (c1), the styrene-type compound represented by a following formula is mentioned.

In the formula, R ² : —H, CH ₃ , —Cl, —CHO, —COOH, —CH ₂ Cl, —CH ₂ NH ₂ , —CH ₂ N (CH ₃ ) ₂ , —CH ₂ N (CH ₃ ) ₃ Cl, —CH ₂ NH ₃ Cl, —CH ₂ CN, —CH ₂ COOH, —CH ₂ N (CH ₂ COOH) ₂ , —CH ₂ SH, —CH ₂ SO ₃ Na or —CH ₂ OCOCH ₃ .

Examples of (c2) include acrylic acid, methacrylic acid, and (meth) acrylate represented by the following formula.
CH ₂ ═C (R ¹ ) —COO—R ³
In the formula, R ^{1 is a} hydrogen atom or a methyl group, and R ^{3 is} —CH ₃ —CH ₂ CH ₂ N (CH ₃ ) ₂ , — (CH ₂ ) _m H (m = 2 to 20), —CH ₂ CH (CH ₃ ) ₂ , —CH ₂ —C (CH ₃ ) ₂ —OCO—Ph, —CH ₂ Ph, —CH ₂ CH ₂ OPh, —CH ₂ N (CH ₃ ) ₃ Cl, — (CH ₂ CH ₂ O) _m CH ₃ (m = 2 to 20), — (CH ₂ ) ₂ —NCO,

It is.

Examples of (c2) further include polyesters of (meth) acrylic acid such as acrylic acid diesters and compounds represented by the following formula.
CH ₂ = C (R ¹ ) -CONH-R ⁴
In the formula, R ^{1 is a} hydrogen atom or a methyl group, and R ^{4 is} —C _m H _{2m + 1} (m = 2 to 20), —H.

Still other polymerizable compounds (c3) include vinyl compounds other than the above (c1) and (c2), such as vinyl chloride (CH ₂ ═CHCl) and acrylonitrile (CH ₂ ═CHCN).
Moreover, as a polymeric compound (c3), the unsaturated ester which has the following epoxy groups is also mentioned.

The polymer according to the present invention can contain, as the polymerized unit (C), a polymerized unit derived from one or more of the compounds (c) as described above. (C) The total amount may be 50% by mass or less, preferably 20% by mass or less.

If the molecular weight of the polymer as described above is small, it will not be possible to exhibit sufficient creeping prevention performance. For this reason, the polymer according to the present invention requires a high molecular weight for sufficiently exhibiting the creeping prevention performance in addition to the structure as described above. Specifically, the polymer has a weight average molecular weight (Mw) of 150,000 or more. The molecular weight is preferably 180,000 or more, more preferably 200,000 or more. However, if the molecular weight is too large, solubility in a solvent and handling of a polymer become difficult, so that it is preferably at most 2 million, more preferably 1 million or less. Even 500,000 or less may be sufficient.
In the present invention, the weight average molecular weight is defined as GPC (gel permeation chromatography; column filler: styrene divinylbenzene copolymer, moving layer: polymethyl methacrylate (standard name) measured by Asahiklin AK-225 (trade name). Substance) The molecular weight in terms of conversion.

The polymer according to the present invention is not particularly limited with respect to the polymerization form and the like except that it includes the above-described polymerization units (A) and (B) and an additional polymerization unit (C). The polymerization form may be any of random, block, graft and the like, and is not particularly limited, but usually a random copolymer is preferred.

The production method is not particularly limited, but in the present invention, it is usually possible to carry out addition polymerization based on unsaturated groups in each compound. The polymerization can be carried out by appropriately adopting known addition polymerization conditions for unsaturated compounds. For example, the polymerization initiation source is not particularly limited, and usual initiators such as organic peroxides, azo compounds and persulfates can be used.

When polymerizing the polymer according to the present invention, other desired components may be used together with the above-mentioned compound as a polymerization raw material within a range not impairing the effects of the present invention. Examples of the other components include the above initiator, a polymerization regulator, a polymerization catalyst, a reactive dye, and an antistatic agent. The total content of such other components in the polymer is preferably 10% by mass or less, more preferably 5% by mass or less, and still more preferably 1% by mass or less.

The scooping preventive agent of the present invention is a liquid composition containing the above-mentioned polymer and usually dissolved or dispersed in a solvent. For this reason, it is a preferred embodiment that the polymer is produced by solution polymerization using a solvent described later as a polymerization medium, and the liquid composition is directly prepared by polymerization. When the polymerization raw material compound is a gas such as vinyl chloride, it may be continuously supplied under pressure using a pressure vessel.

The solvent for forming the composition is not particularly limited as long as it can dissolve or disperse the polymer, and examples thereof include various organic solvents, water, and mixed media thereof. The polymer is particularly easily dissolved in a fluorinated solvent, and hydrochlorofluorocarbon (HCFC) and perfluorocarbon (PFC) can also be used. In consideration of social environmental problems, hydrofluorocarbon (HFC) or hydrofluoroether (HFE) is preferable. Specific examples of usable fluorine-based solvents are shown below, but are not limited thereto.

m-xylene hexafluoride (hereinafter referred to as m-XHF),
p-xylene hexafluoride (hereinafter referred to as p-XHF),
CF ₃ CH ₂ CF ₂ CH ₃ ,
CF ₃ CH ₂ CF ₂ H,
C ₆ F ₁₃ OCH ₃ ,
C ₆ F ₁₃ OC ₂ H ₅ ,
C ₃ F ₇ OCH ₃ ,
C ₃ F ₇ OC ₂ H ₅ ,
C ₆ F ₁₃ H,
CF ₂ HCF ₂ CH ₂ OCF ₂ CF ₂ H,
CF _₃ CFHCFHCF ₂ CH _3,
CF ₃ (OCF ₂ CF ₂ ) _n (OCF ₂ ) _m OCF ₂ H (m and n are each 1 to 20),
C ₃ F ₁₇ OCH ₃ ,
C ₇ F ₁₅ OCH ₃ ,
C ₄ F ₉ OCH ₃ ,
C ₄ F ₉ OC ₂ H ₅ ,
CF ₃ (CF ₂ ) ₃ OC ₂ H ₅ ,
(CF ₃ ) ₂ CFCF ₂ OC ₂ H ₅ ,
C ₄ F ₉ CH ₂ CH ₃ ,
CF ₃ CH ₂ OCF ₂ CF ₂ CF ₂ H,
CF ₃ CF ₂ CHCl ₂ ,
CClF ₂ CF ₂ CHClF
And mixtures of these.
For example, a mixture of CF ₃ CF ₂ CHCl ₂ and CClF ₂ CF ₂ CHClF is a trade name of Asahi Clin AK-225 (manufactured by Asahi Glass Co., Ltd.), and CF ₃ (CF ₂ ) ₃ OC ₂ H ₅ and (CF ₃ ) A hydrofluoroether mixture with ₂ CFCF ₂ OC ₂ H ₅ is available under the trade name Novec HFE 7200 (manufactured by 3M).

The scooping preventive agent of the present invention usually contains the above polymer in a concentration of preferably 0.001 to 10% by mass, more preferably 0.01 to 1% by mass. If the concentration of the polymer is within this range, the creeping prevention performance can be sufficiently exhibited, and the stability of the composition is also good. The concentration of the polymer in the scooping prevention agent may be a final concentration. For example, when the scooping prevention agent is directly prepared as a polymerization composition, the polymer concentration of the polymerization composition immediately after polymerization (solid The partial concentration) may exceed 10% by mass. The high-concentration polymerization composition can be appropriately diluted so that the final desired concentration is obtained.

The scooping preventive agent of the present invention may contain any desired component as long as it does not adversely affect the stability of the composition, the flux scooping prevention performance or the appearance. Such components include, for example, pH control agents, rust preventives for preventing corrosion of the coating surface, the purpose of controlling the concentration of the polymer in the liquid when the composition is diluted, and untreated parts Dyes, dye stabilizers, flame retardants, antifoaming agents, antistatic agents, and the like.

In the present invention, a coating film of the scooping-up preventing agent as described above is formed on a part or all of the soldering portion of the surface of the electronic member, and after treating a part or all of the coating film with a soldering flux, An electronic member soldering method for soldering is provided. In this case, the scooping-up preventing agent can be diluted to an arbitrary concentration according to the purpose and application and coated on the electronic member. As a coating method, a general coating method can be employed. For example, there are methods such as dip coating, spray coating, or coating with an aerosol can filled with the composition of the present invention.

Specific examples of the electronic member include an electronic component having an electrical contact such as a connector, a switch, a volume, or a semi-fixed resistor, and a printed circuit board having an electrical contact. Examples of the location covered with the scooping preventive agent of the present invention include a location where a flux scooping may occur when an electronic component such as a connector is soldered to a printed circuit board. More specifically, a base part of an electronic component such as a connector to be attached to the printed board, a substrate surface on the side of the printed board on which the electronic component main body is mounted, or a through hole provided in the printed board for attaching the electronic component, etc. It is done. Moreover, you may coat | cover the whole surface of an electronic component or a printed circuit board, and can also employ | adopt coating methods other than the above. For example, a method of full immersion or semi-immersion with good coating efficiency can be employed.

It is more preferable to perform drying at a temperature equal to or higher than the boiling point of the solvent after application of the scooping inhibitor. Of course, when heating and drying are difficult due to the material of the parts to be processed, etc., heating should be avoided to dry. In addition, what is necessary is just to select heating conditions according to the composition of the composition to apply | coat, an application area, etc.

The scooping preventive agent of the present invention forms a film on the surface of an electronic member such as an electronic component or a printed circuit board and prevents scooping of the solder flux. Therefore, according to the present invention, an electronic member such as an electronic component or a printed board in which corrosion due to flux is prevented is provided.

An electronic component such as an electronic component or a printed circuit board having a coating (dried) formed on the surface as described above or a printed board is then treated with a soldering flux, and then soldered. The soldering method is not particularly limited, and is performed according to a conventionally known method.
The types of flux and solder are not particularly limited, and those commonly used for soldering electronic members can be used.

The electronic components or electronic members such as printed boards are used as materials for various electric products. The electrical product is an excellent quality electrical product in which a failure caused by corrosion due to flux is prevented. Specific examples of the electric products include devices for computer devices, televisions, audio devices (radio cassettes, compact discs, minidiscs), mobile phones, and the like.

The present invention will be specifically described below, but the present invention is not limited to the following examples. Unless otherwise specified, what is indicated by “%” in the description of the following examples represents “mass%”.
The polymerization monomers used in the following preparation examples are shown in Table 2. All of these compounds are commercially available as reagents.

(Examples 1 to 5)
<Preparation of polymerization composition>
In a closed container, monomer, polymerization solvent (m-XHF), initiator dimethyl 2,2′-azobis (2-methylpropionate) (V-601: Wako Pure Chemical Industries, Ltd., trade name) Each was charged at the charging ratio shown in Table 3, and reacted at 70 ° C. for 26 hours to obtain polymerization compositions 1 to 5. Table 3 shows the molecular weight of each polymer of each polymerization composition determined as follows.
In the following, when diluting the polymerization composition, a predetermined amount of the polymerization composition obtained by the reaction is dried at 120 ° C. for 2 hours, and the dry residue is weighed as a polymer. The coalescence concentration% (mass%) was determined.

[Measurement of weight average molecular weight]
The polymerization composition was diluted with Asahiklin AK-225 (manufactured by Asahi Glass Co., Ltd.) so that the concentration of the polymer was about 1%, and used as a measurement sample. GPC was measured under the following conditions using Shodex GPC-104 manufactured by Showa Denko K.K.
<GPC measurement conditions>
Separtion Column: LF-604 (Filler: Styrene divinylbenzene copolymer, Showa Denko KK) x 2
Default Column: KF600RH (filler: none, Showa Denko KK) x 2
Clean Liquid: AK-225
Flow Rate: 0.2ml / min
Reference material: Polymethylmethacrylate

(Comparative Examples 1 to 9)
Comparative polymerization compositions 1 to 9 were obtained in the same manner as in Example 1 except that the charged monomers listed in Table 3 were used. Table 3 shows the molecular weight of each polymer of each polymerization composition obtained in the same manner as in the Examples.

(Test 1) IPA Repellency Each polymerization composition obtained in the above Examples and Comparative Examples was diluted with HFE7200 (manufactured by 3M), and a flux scooping inhibitor for each solder having a polymer concentration of 0.05% was added. Prepared.
About this solder flux creeping-up inhibitor, the contact angle with respect to IPA was measured and IPA repellency was evaluated. The results are shown in Table 3 above. The contact angle measurement method is as follows.
[Measurement of contact angle]
A test piece subjected to silver plating (3 μm) was immersed in each of the inhibitors for 1 minute at room temperature, then taken out and dried at room temperature to treat the scooping-up inhibitor film. 2-propanol (IPA) was dropped onto the silver plating plate, and the contact angle was measured. For the measurement of the contact angle, an automatic contact angle meter OCA-20 (manufactured by dataphysics) was used.

(Test 2)
The polymerization compositions of Examples 1 to 5 were diluted with HFE7200 to prepare solder flux creep-up inhibitors having a polymer concentration of 1%.
A test piece subjected to silver plating (3 μm) was dipped in each scooping preventive agent at room temperature for 1 minute, then taken out and dried at room temperature, and treated with a scooping preventive agent.

[Measurement of contact resistance]
About each test piece after a process, contact resistance was measured on condition of the following.
Contact resistance Contact resistance evaluation / measurement device: MS2007 (Fact Kei Co., Ltd.)
Probe: Pt, φ = 1mm
Base material: Silver plated plate (10 × 50 × 1 mm, Nippon Test Panel Co., Ltd.)
Treatment conditions: After immersion for 1 minute, air-dry at room temperature for 20 minutes or more.
Measurement load: 5gf-100gf

[Measurement of solder wettability (zero cross time)]
The zero cross time was measured for each test piece after the above treatment.
Zero cross time is a measure of the wettability of the solder, meaning that it is easier to wet in a short time, and the performance is evaluated as good.

SAT-5100 (Resca Co., Ltd.) was used for the zero cross time measurement.
<Measurement conditions>
Solder used: H63A-B20 (eutectic solder, Senju Metal Industry Co., Ltd.)
Solder temperature: 235 ° C
Flux: Rosin flux 25% IPA solution (Senju Metal Industry Co., Ltd.)
Base material: Silver-plated plate (10 x 30 x 0.3 mm, Reska Co., Ltd.)
Immersion conditions: Immersion speed: 20 mm / sec, Immersion depth: 2 mm, Immersion time: 10 sec
Treatment conditions: After immersion for 1 minute, air-dry at room temperature for 20 minutes or more.

Table 4 shows the evaluation results of contact resistance and solder wettability (zero cross time).
As the scooping-up preventing agent, even when the treatment was performed at a concentration of 1% which is considerably higher than the concentration of a general scooping-up preventing agent, the contact resistance was almost the same as that of untreated. From this, it was confirmed that even if a film made of the scooping-up preventing agent is formed on the contact portion of the electrical component, the possibility of contact failure is very low.
Moreover, since the zero cross time after the treatment at the above 1% concentration is also 1 second or less, it has been confirmed that even if the scooping prevention coating is processed on the soldered portion, it does not affect the soldering. .

As described above, the creep-up preventing agent of the present invention has a low concentration of IPA repellency even when the perfluoroalkyl group has 6 or less carbon atoms, and the conventional perfluoroalkyl group has 8 or more carbon atoms. It was equivalent to the one. This indicates that the present invention makes it possible to provide an anti-cracking agent having high performance comparable to that of conventional products while greatly reducing risks to living bodies and the environment.

(Test 3)
The polymerization compositions obtained in Examples 1, 4 and 5 and Comparative Examples 1, 2, 8 and 9 were diluted with HFE7200, and diluted at extremely low concentrations with polymer concentrations of 0.05% and 0.01%. Liquids were prepared and the creeping performance of those fluxes was examined. As an example of a specific climbing performance evaluation, a side type connector 05FDZ-ST (S) (LF) (SN) (manufactured by Nippon Crimp Terminal) was used, and several test conditions were set as follows. Tests were conducted.
The connector part was immersed in the diluted solution for 1 minute, taken out, and dried at room temperature for 30 minutes. The connector part was soaked in the flux for 10 seconds to the root of the lead wire. The component was placed on the board, and the soldering surface was immersed in the flux with the component placed. The soldering surface was dipped in eutectic solder (H63A-B20 Senju Metal Industry Co., Ltd.) melted at 235 ° C. and soldered. The connector parts were disassembled and it was confirmed whether or not the flux crawls up at the contact portions.
Table 5 shows the evaluation results of the flux climbing performance as described above. It has been confirmed that the polymerization composition of the present invention exhibits sufficient performance even at a low concentration.

○: No scooping up ×: Scooping up

Claims

It contains at least one polymer unit (A) derived from a compound represented by the following formula (a) and a polymer unit (B) derived from an unsaturated compound containing a hydroxyl group, and has a weight average molecular weight (polymethyl) Flux creep-up preventing composition for solder containing a polymer having a methacrylate equivalent of 150,000 or more:
CH 2 ═C (R 1 ) —C (O) OQ 1 —R f (a)
In the formula, R 1 : a hydrogen atom or a methyl group,
Q 1 : a single bond or a divalent linking group,
R f represents a polyfluoroalkyl group or polyfluoroether group having a main chain length of 1 to 6 carbon atoms.
The composition according to claim 1, wherein the R f group is a linear perfluoroalkyl group or perfluoroether group having 1 to 6 carbon atoms.
The composition according to claim 1 or 2, wherein the polymerization unit (B) is derived from a compound represented by the following formula (b):
CH 2 ═C (R 1 ) —C (O) O—Q 2 —OH (b)
Wherein, R 1: same as in the formula (a), Q 2: 2 divalent linking group.
The composition according to any one of claims 1 to 3, wherein a ratio of the polymerization unit (B) in the polymer is 10% by mass or less.
An electronic member having a coating made of the composition according to any one of claims 1 to 4 at a soldering position of the electronic member and having a solder flux creeping-up preventing performance.
A solder for an electronic member, wherein a film made of the composition according to any one of claims 1 to 4 is formed at a place to be soldered on the electronic member, a solder flux is applied on the film, and then soldered. Attaching method.
An electrical product including an electronic member soldered by the method according to claim 6.