Brazing material, brazing member, heat exchanger, and method for manufacturing brazing member

Abstract

This brazing material for brazing aluminum or an aluminum alloy includes fluoride-based flux, a solidifying agent, and an amine compound. The brazing material is solid at 25°C. The solidifying agent contains a normal dialcohol with 6 to 10 carbon atoms. The amine compound contains a secondary amino group-containing compound.

Description

Brazing material, brazing member, heat exchanger, and method for manufacturing brazing member

[0001] The present invention relates to a brazing material, a brazing member, a heat exchanger, and a method for manufacturing a brazing member.

[0002] Conventionally, in welding metal members, a liquid flux composition (liquid brazing material) is used to remove oxides from the metal members. Liquid flux compositions are liquid at room temperature and have fluidity, so they may not be sufficiently easy to handle and work with. Therefore, a solid flux composition (solid brazing material) is required.

[0003] The following brazing material has been proposed as a solid flux composition (solid brazing material). More specifically, the brazing material contains a fluoride-based flux, a solidifier, and an organic viscosity reducer, and is solid at 25°C. In addition, as a method for applying the brazing material, for example, a method for rubbing the brazing material against a substrate, and a method for heating and melting the brazing material and discharging it onto a substrate using a discharging device have been proposed (see, for example, Patent Document 1).

[0004] International Publication No. 2020 / 040128

[0005] In recent years, in addition to the above-mentioned friction coating method (friction method) and the above-mentioned discharge coating method (dispense method), a spray coating method has been investigated as a method for coating a brazing material.

[0006] However, when the brazing material is heated and melted, the flux may aggregate, which may result in insufficient applicability (spray applicability) in the spray method.

[0007] Furthermore, when the spray method is used, the amount of brazing material applied may increase, which may result in an increase in the amount of components (solidifiers) other than the flux adhering to the base material, resulting in a decrease in brazability.

[0008] The present invention provides a brazing material having excellent applicability (particularly spray applicability) and brazing ability, a brazed member, a heat exchanger, and a method for manufacturing a brazed member.

[0009] The present invention [1] provides a brazing material for brazing aluminum or an aluminum alloy, the brazing material comprising a fluoride-based flux, a solidifying agent, and an amine compound, and being solid at 25°C, the solidifying agent containing a normal dialcohol having 6 to 10 carbon atoms, and the amine compound containing a secondary amino group.

[0010] The present invention [2] includes the brazing material according to the above [1], wherein the ClogP value of the secondary amino group-containing compound is −1.85 to 5.00.

[0011] The present invention [3] includes the brazing material according to the above [1] or [2], wherein the content ratio of the amine compound is 3 to 5000 parts by mass relative to 100 parts by mass of the fluoride-based flux.

[0012] The present invention [4] includes a brazed member comprising aluminum or an aluminum alloy and a coating film formed by applying the brazing material according to any one of the above [1] to [3] to the aluminum or the aluminum alloy.

[0013] The present invention [5] includes a heat exchanger comprising the assembly of brazed members according to the above [4].

[0014] The present invention [6] includes a method for manufacturing a brazed member, comprising: a processing step of processing a base material made of aluminum or an aluminum alloy; and an application step of heating and melting the brazing material according to any one of the above [1] to [3], supplying it to a spraying device, and spraying it onto the base material.

[0015] The present invention [7] includes a method for manufacturing a brazed member, comprising: a processing step of processing a base material made of aluminum or an aluminum alloy; and an application step of heating and melting the brazing material according to any one of the above [1] to [3], supplying it to a discharge device, and discharging it onto the base material.

[0016] The present invention [8] includes a method for manufacturing a brazed member, comprising: a processing step of processing a base material made of aluminum or an aluminum alloy; and an application step of applying the brazing material according to any one of the above [1] to [3] to the base material by rubbing.

[0017] The brazing member of the present invention contains a solidifying agent and an amine compound. The solidifying agent contains a normal dialcohol having 6 to 10 carbon atoms, and the amine compound contains a compound containing a secondary amino group. Therefore, in the brazing member, aggregation of the fluoride-based flux is suppressed. As a result, the brazing material has excellent applicability (especially spray applicability) and brazing properties.

[0018] The brazing material is used in the brazing member, the heat exchanger, and the method for manufacturing the brazing member of the present invention, and therefore the brazing member, the heat exchanger, and the method for manufacturing the brazing member of the present invention provide excellent application properties and brazing properties.

[0019] Fig. 1 is a schematic perspective view showing one embodiment of a heat exchanger of the present invention. Fig. 2 is an exploded perspective view of a plate-bonded tube used in the heat exchanger shown in Fig. 1. Fig. 3A shows a process for processing an Al base material, and Fig. 3B shows a process for applying a brazing material to the Al base material.

[0020] 1. Brazing Material [Brazing Components] The brazing material of the present invention is a brazing material for brazing aluminum or an aluminum alloy. The brazing material contains, as essential components, a fluoride-based flux, a solidifying agent, and an amine compound.

[0021] Hereinafter, the fluoride-based flux, the solidifying agent, and the amine compound may be collectively referred to as the “brazing components.” That is, the brazing material contains the brazing components as essential components, and the brazing components are made up of the fluoride-based flux, the solidifying agent, and the amine compound.

[0022] As will be described later, the brazing material may contain a brazing material (for example, a metal powder) as an optional component in addition to the brazing components. The brazing material is not included in the brazing components.

[0023] The content of the brazing components is, for example, 50 to 100 mass%, preferably 70 to 100 mass%, relative to the total amount of the brazing material. When the brazing material contains a brazing material (optional component, described later), the content of the brazing components is, for example, 50 to 90 mass%, preferably 70 to 80 mass%, relative to the total amount of the brazing material.

[0024] [Fluoride-based flux] Examples of fluoride-based fluxes include Cs-Al-F-based fluxes, K-Zn-F-based fluxes, and K-Al-F-based fluxes. Cs-Al-F-based fluxes contain cesium (Cs), aluminum (Al), and fluorine (F). Examples of Cs-Al-F-based fluxes include cesium fluoroaluminate (non-reactive cesium-based flux), specifically CsAlF ４ , Cs ２ AlF ５ , and Cs ３ AlF ６ The K-Zn-F flux contains potassium (K), zinc (Zn) and fluorine (F). Examples of the K-Zn-F flux include potassium zinc fluoride, specifically KZnF. ３ The K-Al-F flux contains potassium (K), aluminum (Al) and fluorine (F). Examples of the K-Al-F flux include potassium fluoroaluminate, specifically KAlF ４ , K. ２ AlF ５ , and K ３ AlF ６ These may be used alone or in combination of two or more. A preferred example of the fluoride-based flux is a K-Al-F-based flux.

[0025] From the viewpoint of application property and brazing property, the blending ratio of the fluoride-based flux relative to the total amount of the brazing components (fluoride-based flux, solidifying agent, and amine compound) is, for example, 1 to 80 mass%, preferably 5 to 70 mass%, more preferably 5 to 60 mass%, even more preferably 10 to 50 mass%, still more preferably 30 to 50 mass%, and particularly preferably 35 to 45 mass%.

[0026] In particular, from the viewpoint of brazing performance, the lower limit of the blending ratio of the fluoride-based flux is, for example, 1 mass % or more, preferably 5 mass % or more, more preferably 10 mass % or more, even more preferably 30 mass % or more, and particularly preferably 35 mass % or more, relative to the total amount of the brazing components (fluoride-based flux, solidifying agent, and amine compound).

[0027] From the viewpoint of application properties, the upper limit of the blending ratio of the fluoride-based flux relative to the total amount of the brazing components (fluoride-based flux, solidifying agent, and amine compound) is, for example, 80 mass % or less, preferably 70 mass % or less, more preferably 60 mass % or less, even more preferably 50 mass % or less, and particularly preferably 45 mass % or less.

[0028] [Solidifying Agent] The solidifying agent is a component that adjusts the melting temperature so that the brazing material becomes solid at 25°C and improves shape retention. The solidifying agent does not include known gelling agents, and is distinguished from the gelling agent. The solidifying agent does not include the amine compounds described below, and is distinguished from the amine compounds. More specifically, the solidifying agent contains a normal dialcohol having 6 to 10 carbon atoms.

[0029] The normal dialcohol having 6 to 10 carbon atoms is a linear aliphatic alcohol (C6 to 10 linear aliphatic dihydric alcohol) having two hydroxyl groups per molecule. Examples of normal dialcohols having 6 to 10 carbon atoms include 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol. These can be used alone or in combination of two or more. Preferred examples of normal dialcohols having 6 to 10 carbon atoms include linear aliphatic dihydric alcohols having 6 to 9 carbon atoms, more preferably linear aliphatic dihydric alcohols having 7 to 9 carbon atoms, even more preferably linear aliphatic dihydric alcohols having 8 to 9 carbon atoms, and particularly preferably linear aliphatic dihydric alcohols having 9 carbon atoms (i.e., 1,9-nonanediol). These can be used alone or in combination of two or more types.

[0030] The solidifying agent may further contain other solidifying agents. The other solidifying agents are solidifying agents excluding normal dialcohols having 6 to 10 carbon atoms. Examples of the other solidifying agents include the solidifying agents described in paragraphs

[0051] to

[0092] of WO 2020 / 040128 (excluding normal dialcohols having 6 to 10 carbon atoms).

[0031] More specifically, examples of other solidifying agents include hydrocarbons that are solid at room temperature, alkyl alcohols that are solid at room temperature (excluding normal dialcohols having 6 to 10 carbon atoms), ether alcohols that are solid at room temperature, and high-carbon carboxylic acid-high-carbon alcohol esters. Examples of hydrocarbons that are solid at room temperature include natural waxes and synthetic waxes. Examples of alkyl alcohols that are solid at room temperature (excluding normal dialcohols having 6 to 10 carbon atoms) include normal monools having 14 to 30 carbon atoms, normal dialcohols having 11 to 30 carbon atoms, and trihydric or higher alcohols having 5 to 30 carbon atoms. Examples of normal monools having 14 to 30 carbon atoms include tetradecanol, hexadecanol, octadecanol, and eicosanol. Examples of normal dialcohols having 11 to 30 carbon atoms include 1,11-undecanediol, 1,12-dodecanediol, and 1,20-eicosanediol. Examples of trihydric or higher alcohols having 5 to 30 carbon atoms include trimethylolpropane and pentaerythritol. Examples of ether alcohols that are solid at room temperature include polyether monools and polyether glycols. Examples of polyether monools include polyethylene glycol monomethyl ether and polyethylene glycol monoethyl ether. Examples of polyether glycols include polyoxyethylene glycol, polyoxypropylene glycol, and polyoxybutylene glycol. Examples of high-carbon carboxylic acid-high-carbon alcohol esters include reaction products of carboxylic acids having 10 or more carbon atoms with alcohols having 8 or more carbon atoms. Examples of carboxylic acids having 10 or more carbon atoms include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, decanedioic acid, dodecanedioic acid, and anhydrides thereof. Examples of alcohols having 8 or more carbon atoms include octyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, linolyl alcohol, octanediol, nonanediol, decanediol, and dodecanediol.More specific examples of the high-carbon carboxylic acid-high-carbon alcohol ester include carnauba wax, candelilla wax, and triacontanyl palmitate. These can be used alone or in combination of two or more.

[0032] From the viewpoint of coatability, the content of other solidifying agents (solidifying agents excluding normal dialcohols having 6 to 10 carbon atoms) is, for example, 0 to 20 mass%, preferably 0 to 10 mass%, more preferably 0 to 5 mass%, and particularly preferably 0 mass%, relative to the total amount of solidifying agents.

[0033] That is, from the viewpoint of coatability, the content of the normal dialcohol having 6 to 10 carbon atoms is, for example, 80 to 100 mass%, preferably 90 to 100 mass%, more preferably 95 to 100 mass%, and particularly preferably 100 mass%, relative to the total amount of the solidifier.

[0034] That is, from the viewpoint of coatability, the solidifying agent is particularly preferably made of a normal dialcohol having 6 to 10 carbon atoms.

[0035] From the viewpoint of application property and brazing property, the content of the solidifying agent relative to the total amount of the brazing components (fluoride-based flux, solidifying agent, and amine compound) is, for example, 1 to 95 mass%, preferably 10 to 90 mass%, more preferably 30 to 80 mass%, even more preferably 35 to 70 mass%, still more preferably 39.5 to 60 mass%, still more preferably 40 to 60 mass%, and particularly preferably 50 to 60 mass%.

[0036] In particular, from the viewpoint of application property, the lower limit of the content of the solidifying agent is, for example, 1 mass % or more, preferably 10 mass % or more, more preferably 30 mass % or more, even more preferably 35 mass % or more, even more preferably 39.5 mass % or more, still more preferably 40 mass % or more, and particularly preferably 50 mass % or more, relative to the total amount of the brazing components (fluoride-based flux, solidifying agent, and amine compound).

[0037] From the viewpoint of brazing performance, the upper limit of the content of the solidifying agent relative to the total amount of the brazing components (fluoride-based flux, solidifying agent, and amine compound) is, for example, 95 mass % or less, preferably 90 mass % or less, more preferably 80 mass % or less, even more preferably 70 mass % or less, still more preferably 60 mass % or less, even more preferably 60 mass % or less, and particularly preferably 60 mass % or less.

[0038] Moreover, from the viewpoint of application property and brazing property, the content of the solidifying agent relative to 100 parts by mass of the fluoride-based flux is, for example, 1 to 2000 parts by mass, preferably 10 to 1000 parts by mass, more preferably 50 to 500 parts by mass, still more preferably 100 to 300 parts by mass, and particularly preferably 120 to 200 parts by mass.

[0039] [Amine Compound] The amine compound improves the mixing stability of the fluoride-based flux and the solidifying agent in the molten brazing material, and reduces the melt viscosity of the brazing material. In other words, the amine compound is a viscosity reducer (surfactant) that has a viscosity reducing effect (surface activity).

[0040] The amine compound includes a secondary amino group-containing compound.

[0041] A secondary amino group-containing compound is a compound having one or more secondary amino groups per molecule. The secondary amino group-containing compound is not particularly limited in other structure as long as it has one or more secondary amino groups per molecule. For example, the secondary amino group-containing compound may or may not contain other amino groups (e.g., primary amino groups and tertiary amino groups). Furthermore, the secondary amino group-containing compound may or may not contain functional groups other than amino groups (e.g., hydroxyl groups and mercapto groups).

[0042] That is, examples of secondary amino group-containing compounds include those that contain a secondary amino group but do not contain other amino groups and do not contain functional groups other than amino groups. Examples of such secondary amino group-containing compounds include dibutylamine, diethylamine, dipropylamine, N-butylethylamine, and diisopropylamine. These can be used alone or in combination of two or more types.

[0043] In addition, the secondary amino group-containing compound may be, for example, a secondary amino group-containing compound that contains a secondary amino group, other amino groups, and no functional groups other than amino groups. Examples of such secondary amino group-containing compounds include diaminodiethylamine, diaminodiphenylamine, diaminodipropylamine, diaminodipropylpropanediamine, triethyltetramine, tetraethylenepentamine, pentaethylhexaneamine, and aminomethylpiperazine. These may be used alone or in combination of two or more.

[0044] Examples of secondary amino group-containing compounds include those that contain a secondary amino group, no other amino groups, and a functional group other than an amino group. Examples of such secondary amino group-containing compounds include mono-n-dibutylethanolamine, diethanolamine, dodecylethanolamine, ethylaminoethanol, dipropargylamine, and methylaminoethanol. These can be used alone or in combination of two or more types.

[0045] In addition, the secondary amino group-containing compound may be, for example, a secondary amino group-containing compound containing a secondary amino group, another amino group, or a functional group other than an amino group. Such a secondary amino group-containing compound may, for example, be aminoethylethanolamine. These may be used alone or in combination of two or more types.

[0046] The secondary amino group-containing compound preferably includes a secondary amino group-containing compound that does not contain other amino groups but contains a functional group other than an amino group, and a secondary amino group-containing compound that contains other amino groups and contains a functional group other than an amino group.The secondary amino group-containing compound more preferably includes a secondary amino group-containing compound that contains other amino groups and contains a functional group other than an amino group, and even more preferably includes aminoethylethanolamine.

[0047] The secondary amino group-containing compound is preferably selected based on its Clog P value. From the viewpoints of coatability and hard cake resistance, the Clog P value of the secondary amino group-containing compound is, for example, −2.00 to 8.00, preferably −1.90 to 6.00, more preferably −1.85 to 5.00, even more preferably −1.60 to 3.00, still more preferably −1.50 to 2.00, still more preferably −1.30 to 1.50, and particularly preferably −1.00 to 1.00.

[0048] In particular, from the viewpoint of improving melt stability and suppressing hard caking, the lower limit of the ClogP value of the secondary amino group-containing compound is, for example, −2.00 or more, preferably −1.90 or more, more preferably −1.85 or more, even more preferably −1.60 or more, still more preferably −1.50 or more, still more preferably −1.30 or more, and particularly preferably −1.00 or more.

[0049] Furthermore, from the viewpoint of improving the dispersibility of the flux, suppressing aggregation, and obtaining a uniform coating film, the upper limit of the ClogP value of the secondary amino group-containing compound is, for example, 8.00 or less, preferably 6.00 or less, more preferably 5.00 or less, even more preferably 3.00 or less, still more preferably 2.00 or less, still more preferably 1.50 or less, and particularly preferably 1.00 or less.

[0050] The ClogP value is a logP value calculated by calculation. The logP value is the logarithm of the n-octanol / water partition coefficient (P), and is a parameter indicating the degree of hydrophobicity and hydrophilicity. In the present application, the ClogP value is calculated using, for example, a commercially available software package (e.g., ChemDraw Ultra ver. 14.0 (CambridgeSoft Corporation, USA)) (the same applies hereinafter).

[0051] The amine compound may further contain other amine compounds. The other amine compounds are amine compounds other than secondary amino group-containing compounds, and are amine compounds that do not contain a secondary amino group (hereinafter referred to as secondary amino group-free compounds). Examples of secondary amino group-free compounds include primary amino group-containing compounds that do not contain a secondary amino group, and tertiary amino group-containing compounds that do not contain a secondary amino group. Examples of primary amino group-containing compounds that do not contain a secondary amino group include ethanolamine, behenylamine acetate, and laurylamine acetate. Examples of tertiary amino group-containing compounds that do not contain a secondary amino group include triethylamine and triethanolamine. These compounds may be used alone or in combination of two or more.

[0052] From the viewpoint of coatability, the content of other amine compounds (amine compounds excluding secondary amino group-containing compounds) is, for example, 0 to 20 mass%, preferably 0 to 10 mass%, more preferably 0 to 5 mass%, and particularly preferably 0 mass%, relative to the total amount of the amine compounds.

[0053] That is, from the viewpoint of coatability, the content of the secondary amino group-containing compound is, for example, 80 to 100 mass%, preferably 90 to 100 mass%, more preferably 95 to 100 mass%, and particularly preferably 100 mass%, relative to the total amount of the amine compounds.

[0054] That is, from the viewpoint of coatability, it is particularly preferable that the amine compound is a secondary amino group-containing compound.

[0055] From the viewpoint of application property and hard cake resistance, the content of the amine compound is, for example, 0.01 to 20 mass%, preferably 0.05 to 10 mass%, more preferably 0.1 to 5 mass%, even more preferably 0.2 to 1 mass%, and particularly preferably 0.3 to 0.6 mass%, relative to the total amount of the brazing components (fluoride-based flux, solidifying agent, and amine compound).

[0056] In particular, from the viewpoint of application property, the lower limit of the content of the amine compound is, for example, 0.01 mass % or more, preferably 0.05 mass % or more, more preferably 0.1 mass % or more, even more preferably 0.2 mass % or more, and particularly preferably 0.3 mass % or more, relative to the total amount of the brazing components (fluoride-based flux, solidifying agent, and amine compound).

[0057] Furthermore, from the viewpoint of hard cake resistance, the upper limit of the content of the amine compound relative to the total amount of the brazing components (fluoride-based flux, solidifying agent, and amine compound) is, for example, 20 mass % or less, preferably 10 mass % or less, more preferably 5 mass % or less, even more preferably 1 mass % or less, and particularly preferably 0.6 mass % or less.

[0058] Moreover, from the viewpoint of application property and hard cake resistance, the content ratio of the amine compound relative to 100 parts by mass of the fluoride-based flux is, for example, 1 to 10,000 parts by mass, preferably 3 to 5,000 parts by mass, more preferably 10 to 2,500 parts by mass, still more preferably 50 to 1,000 parts by mass, and particularly preferably 100 to 300 parts by mass.

[0059] In particular, from the viewpoint of improving the dispersibility of the flux and suppressing aggregation, the lower limit of the content of the amine compound is, for example, 1 part by mass or more, preferably 3 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 50 parts by mass or more, and particularly preferably 100 parts by mass or more.

[0060] Furthermore, from the viewpoint of improving melt stability and suppressing hard caking, the upper limit of the content of the amine compound relative to 100 parts by mass of the fluoride-based flux is, for example, 10,000 parts by mass or less, preferably 5,000 parts by mass or less, more preferably 2,500 parts by mass or less, even more preferably 1,000 parts by mass or less, and particularly preferably 300 parts by mass or less.

[0061] [Brazing Material] The brazing material can contain a brazing material as an optional component to improve work efficiency. Examples of brazing materials include metals that can be alloyed with aluminum, and also alloys of such metals with aluminum. The brazing material can also contain other metals in appropriate proportions. More specific examples of brazing materials include metal silicon and silicon-aluminum alloys. These can be used alone or in combination of two or more types. The brazing material is preferably a metal powder. The average particle size of the metal powder is not particularly limited and can be set appropriately depending on the purpose and application.

[0062] The blending ratio of the brazing material is not particularly limited, but is, for example, 0 to 70 mass%, preferably 5 to 60 mass%, more preferably 10 to 50 mass%, and even more preferably 20 to 40 mass%, relative to the total amount of the brazing material.

[0063] The content of the brazing material is not particularly limited, but is, for example, 3 to 300 parts by mass, preferably 5 to 100 parts by mass, and more preferably 10 to 50 parts by mass relative to 100 parts by mass of the brazing components.

[0064] [Additives] The brazing material may contain known additives as optional components to improve work efficiency. Examples of additives include antioxidants, corrosion inhibitors, antifoaming agents, thickeners, and colorants. These may be used alone or in combination of two or more. The amount and timing of addition of the additives are appropriately determined depending on the purpose and application. For example, the content of the additives is 10 mass% or less with respect to the total amount of the brazing material. Note that the brazing material may contain a gelling agent if necessary, but preferably does not contain a gelling agent from the viewpoint of brazing properties (appearance).

[0065] [Preparation of brazing material] The brazing material is obtained by mixing and stirring the above-mentioned components in the above-mentioned proportions by a known method. At this time, the fluoride-based flux is dispersed by the amine compound, and the brazing material is solidified by the solidifying agent. That is, the brazing material is solid, specifically, solid at 25°C.

[0066] "Solid" at 25°C is defined as a substance that is determined to be "not liquid" after testing at 25°C in accordance with the method described in "Method for Confirming Liquidity" in "Fire Department Hazard No. 11: Promulgation of the Cabinet Order Partially Amending the Cabinet Order Concerning the Control of Hazardous Materials (Part Relating to the Testing and Properties of Hazardous Materials) and the Ministerial Ordinance Concerning the Testing and Properties of Hazardous Materials (Notice)."

[0067] The brazing material is softened by heating. More specifically, for example, when the brazing material is applied to aluminum or an aluminum alloy, the solid brazing material is heated, as will be described in detail later. As a result, the brazing material softens and melts.

[0068] The heating temperature is, for example, 40 to 400° C., preferably 50 to 300° C., and more preferably 60 to 150° C. In other words, the brazing material is preferably in a molten state at least at 150° C.

[0069] From the viewpoint of spray application properties, the viscosity of the brazing material at 60°C (molten state) is, for example, 0.01 to 50 Pa s, preferably 0.03 to 10 Pa s, more preferably 0.05 to 5 Pa s, even more preferably 0.09 to 5 Pa s, and particularly preferably 0.1 to 2 Pa s.

[0070] [Application of Brazing Material] The brazing material is applied to aluminum or an aluminum alloy, and then solidifies to form a coating (solid coating).

[0071] An example of the application method is the spray method. In the spray method, the brazing material is heated and melted, and then the molten brazing material is supplied to a known spraying device (spray). The molten brazing material is then sprayed onto any desired object to be coated. As a result, a coating film of the brazing material is formed on the surface of any desired object to be coated. The spray method allows for the formation of a uniform coating film with good workability.

[0072] Another example of the application method is the dispense method. In the dispense method, the brazing material is heated and melted, and then the molten brazing material is supplied to a dispenser. The molten brazing material is then dispensed onto a desired object. As a result, a coating film of the brazing material is formed on the surface of the desired object. The dispense method allows the coating film of the brazing material to be formed more accurately at a desired position.

[0073] Another application method is, for example, a friction method. In the friction method, a solid brazing material is rubbed against an arbitrary object to be coated without heating and melting the brazing material. As a result, a coating film of the brazing material is formed on the surface of the arbitrary object to be coated. The friction method allows the brazing material to be applied with better workability.

[0074] The coating method is not limited to the above, and known methods may be used. More specifically, the coating method is not particularly limited, and examples thereof include brush coating, roll coating, spin coating, dip coating, spray coating, bar coating, knife coating, die coating, inkjet coating, and gravure coating. The coating amount (coating thickness) of the brazing material is appropriately set depending on the purpose and application.

[0075] [Effects] The brazing member contains a solidifying agent and an amine compound. The solidifying agent contains a normal dialcohol having 6 to 10 carbon atoms, and the amine compound contains a compound containing a secondary amino group. Therefore, in the brazing member, aggregation of the fluoride-based flux is suppressed. As a result, the brazing material has excellent applicability (especially spray applicability) and brazing properties.

[0076] More specifically, the nucleophilicity of an amino group is determined, for example, by the number of electron-donating groups bonded to the nitrogen atom and the influence of the nitrogen atom's lone electron pair. Of primary, secondary, and tertiary amino groups, secondary amino groups have the highest nucleophilicity. In other words, compounds containing secondary amino groups (secondary amino group-containing compounds) have relatively higher nucleophilicity than compounds not containing secondary amino groups (secondary amino group-free compounds). Therefore, secondary amino group-containing compounds can be well adsorbed to fluoride-based fluxes, improving the dispersibility of the fluoride-based fluxes. In other words, if an amine compound contains a secondary amino group-containing compound, aggregation of the fluoride-based flux can be suppressed, ensuring excellent application properties.

[0077] On the other hand, when the amine compound contains a secondary amino group-containing compound, depending on the type of solidifier, the compatibility between the amine compound and the solidifier may not be sufficient, which may cause a decrease in coatability (homogeneity) and brazability.

[0078] In contrast, the solidifying agent of the brazing material described above contains a normal dialcohol having 6 to 10 carbon atoms. Therefore, even when the amine compound contains a secondary amino group-containing compound, the amine compound and the solidifying agent have good compatibility. As a result, excellent coatability (uniformity) and brazing properties are obtained.

[0079] 2. Brazed Member and Heat Exchanger The brazed member and the heat exchanger will be described in detail below.

[0080] In FIG. 1, a heat exchanger 1 is a laminated heat exchanger used in, for example, an air conditioner, and has a known laminated structure.

[0081] Specifically, the heat exchanger 1 includes a tube stack 3 formed by stacking a plurality of plate-bonded tubes 2 , and a refrigerant supply / discharge pipe 4 for supplying and discharging a refrigerant to the tube stack 3 .

[0082] In the tube stack 3, the plate-joined tube 2 is a hollow member having a substantially flat shape, and as shown in FIG. 2, includes a pair (two) of plate members 5 arranged opposite each other, and two inner fins 6 arranged inside the plate members 5.

[0083] Each plate member 5 is a member (Al member) made of aluminum or an aluminum alloy, has a roughly rectangular shape when viewed from above, and has a recess 7 that is roughly rectangular when viewed from above and extends along the longitudinal direction at approximately the center of its longitudinal direction (the region excluding both longitudinal ends).

[0084] The recess 7 has a protrusion 8 (rib) extending along the longitudinal direction of the recess 7 at the center in the width direction perpendicular to the longitudinal direction. That is, the protrusion 8 divides the recess 7 into a recess 7a on one side in the width direction and a recess 7b on the other side in the width direction.

[0085] A first through hole 9 is formed at one longitudinal end of the recess 7a.

[0086] A second through hole 10 is formed at the other longitudinal end of the recess 7a.

[0087] A third through hole 11 is formed at one longitudinal end of the recess 7b.

[0088] A fourth through hole 12 is formed at the other longitudinal end of the recess 7b.

[0089] A groove 13 is formed between the first through hole 9 and the third through hole 11, thereby allowing a refrigerant (described later) to flow between the first through hole 9 and the third through hole 11. Note that no groove 13 is formed between the second through hole 10 and the fourth through hole 12, and they are independent of each other.

[0090] The inner fins 6 are made of aluminum or an aluminum alloy (Al members), and one is provided in the recess 7 a and one in the recess 7 b (two in total). Specifically, each inner fin 6 has a corrugated shape that is approximately the same size as the recesses 7 a and 7 b, and is capable of being housed in a refrigerant passage 15 (described later).

[0091] As will be described in detail later, the plate-joined tube 2 is formed by brazing the pair of plate members 5 and the inner fins 6 together.

[0092] 1, a plurality of the obtained plate-bonded tubes 2 are stacked so that the first through holes 9, the second through holes 10, the third through holes 11, and the fourth through holes 12 overlap one another to form a refrigerant supply / discharge path 16. The stacked plate-bonded tubes 2 are then fixed by outer plates 17 on both sides in the stacking direction.

[0093] More specifically, the outer plate 17 on one side (rear side) in the stacking direction blocks the first through hole 9, the second through hole 10, the third through hole 11, and the fourth through hole 12. On the other hand, the outer plate 17 on the other side (front side) in the stacking direction blocks the third through hole 11 and the fourth through hole 12, and leaves the first through hole 9 and the second through hole 10 open.

[0094] This produces a tube stack 3. In the tube stack 3, partition plates for adjusting the flow path of the refrigerant and outer fins for improving heat exchange efficiency may be provided between the plate-bonded tubes 2, as needed.

[0095] The refrigerant supply / discharge pipe 4 includes a refrigerant supply pipe 18 for supplying the refrigerant to the tube stack 3 and a refrigerant discharge pipe 19 for discharging the refrigerant from the tube stack 3 .

[0096] One end of the refrigerant supply pipe 18 is connected to the first through-hole 9, and the other end is connected to a refrigerant tank (not shown). The refrigerant tank stores a known refrigerant such as hydrofluoroolefin.

[0097] The refrigerant discharge pipe 19 has one end connected to the second through hole 10 and the other end connected to a refrigerant recovery tank (not shown).

[0098] In this heat exchanger 1, by supplying the refrigerant X from the refrigerant supply pipe 18 to the refrigerant passage 15 inside the plate-bonded tube 2, heat exchange occurs between the refrigerant X flowing inside the tube stack 3 and the air-conditioning air Y flowing outside the tube stack 3, thereby cooling the air-conditioning air Y.

[0099] A method for manufacturing the plate-jointed tube 2 and the brazing plate 20 as a brazing member for obtaining the plate-jointed tube 2 will be described in detail below.

[0100] That is, in the manufacture of the plate-joined tube 2, first, a brazing plate 20 is manufactured, which includes a plate member 5 (Al member) and a coating film 29 of brazing material formed on the surface of the plate member 5, and then the obtained brazing plate 20 is brazed to the above-mentioned inner fin 6.

[0101] In manufacturing the brazing plate 20, for example, as shown in FIG. 3 , a substrate 22 (hereinafter referred to as an Al substrate) made of a thin plate of aluminum or an aluminum alloy is prepared, and after processing the Al substrate 22, the above-described brazing material is applied to the Al substrate 22.

[0102] In FIG. 3, the Al base 22 is moved in a predetermined direction (for example, from the left side to the right side of the drawing) by a moving device 23 such as a belt conveyor.

[0103] Then, the following steps shown in FIG. 3A (processing step) and FIG. 3B (coating step) are carried out continuously from the upstream side to the downstream side of the moving device 23 .

[0104] That is, in this method, as shown in FIG. 3A, first, the Al base 22 is processed (processing step).

[0105] More specifically, the Al base 22 is processed and formed into a predetermined shape (for example, the shape of the plate member 5) while being intermittently moved in a predetermined direction in the production line.

[0106] The processing method is not particularly limited, and for example, a known processing device 30 such as a press processing device, a bending processing device, or a cutting processing device may be used.

[0107] As a result, the plate member 5 (see FIG. 2) is obtained as the processed Al base material 22.

[0108] Next, in this method, as shown in FIG. 3B, the brazing material 27 is heated and melted, and the resulting liquid molten composition 28 is applied to the plate member 5 (application step).

[0109] More specifically, in the application step, a molten composition 28 of the brazing material 27 is applied to the recess 7 of the plate member 5 (see FIG. 2).

[0110] The heating temperature of the brazing material 27 is, for example, 40 to 400°C, preferably 50 to 300°C, and more preferably 60 to 150°C.

[0111] Furthermore, a spray method is preferably used as a method for applying the molten composition 28. That is, the molten composition 28 is preferably supplied to a spraying device 31 and sprayed onto the plate member 5 (Al substrate 22). The spraying conditions (temperature, pressure, etc.) in the spraying device 31 (spraying) are appropriately set depending on the purpose and application. By using the spraying device 31 (spraying), the molten composition 28 can be applied to obtain a more uniform coating film (solidified coating film) 29. The thickness of the coating film 29 is not particularly limited, but is, for example, 1 to 1000 μm, preferably 5 to 200 μm.

[0112] As a result, a brazing plate 20 including the plate member 5 (Al base material 22) and the coating film 29 can be obtained.

[0113] Such a brazing plate 20 has excellent brazing properties because it is provided with the coating film 29 formed by applying the brazing material 27 to the plate member 5 (Al base material 22).

[0114] Therefore, the obtained brazing plate 20 is suitable for use in manufacturing the plate-bonded tube 2 and the heat exchanger 1 .

[0115] More specifically, as shown in Figures 1 and 2, a pair of brazing plates 20 (plate members 5) are arranged opposite each other, and inner fins 6 are arranged between the pair of brazing plates 20 (plate members 5) so as to correspond to the recesses 7a and 7b.

[0116] Then, each inner fin 6 is brazed to the recessed portion 7a and recessed portion 7b, and at the same time, the contact portions (peripheral edges and protruding portions 8) of the pair of brazing plates 20 (plate members 5) are brazed to each other.

[0117] As a result, the pair of brazing plates 20 (plate members 5) are joined together, and the opposing recesses 7a and 7b form a hollow space, forming two refrigerant passages 15. In addition, inner fins 6 are fixed to the refrigerant passages 15.

[0118] In this way, a plate-bonded tube 2 can be obtained, and by stacking such plate-bonded tubes 2, a heat exchanger 1 having a bonded assembly of the above-mentioned brazing plates 20 (brazing members) can be obtained.

[0119] The heat exchanger 1 obtained is obtained using the brazing plate 20 described above, and therefore has excellent brazing properties.

[0120] The brazed member and heat exchanger described above are suitable for use as heat exchangers for air conditioners used in, for example, the passenger compartment of an automobile or the interior of a house.

[0121] The method for manufacturing a brazed member described above uses the brazing material described above, and therefore, the method for manufacturing a brazed member described above provides excellent applicability (particularly spray applicability) and brazing properties.

[0122] In the above description, the brazing material 27 is applied to the plate member 5 by a spray method, but the application method is not limited to the spray method. For example, the brazing material 27 can also be applied to the plate member 5 by the above-mentioned dispense method and friction method.

[0123] For example, when the dispensing method is employed, first, the Al base 22 is processed in the processing step. Next, in the application step, the solid brazing material 27 is heated and melted. Thereafter, the molten brazing material 27 is supplied to a known discharge device (e.g., a jet dispenser) and discharged onto the Al base 22. As a result, the coating film (solidified coating film) 29 is formed. Such a manufacturing method for a brazed member also has excellent application properties and brazing properties because the brazing material is used.

[0124] Furthermore, for example, when the friction method is employed, first, the Al base 22 is processed in the above-described processing step. Next, the solid brazing material 27 is rubbed against the Al base 22 by a known method without being heated and melted. This scrapes off the solid brazing material 27, and the scraped brazing material 27 adheres to the Al base 22. As a result, the coating film (solidified coating film) 29 is formed. Such a manufacturing method for a brazed member also has excellent coatability and brazeability because the above-described brazing material is used.

[0125] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to the following examples. Note that "parts" and "%" are by mass unless otherwise specified. Furthermore, specific numerical values ​​such as blending ratios (content ratios), physical property values, parameters, etc. used in the following description can be substituted with the corresponding upper limit values ​​(numeric values ​​defined as "equal to or less than") or lower limit values ​​(numeric values ​​defined as "equal to or more than" or "exceeding") of the blending ratios (content ratios), physical property values, parameters, etc. described in the above "Modes for Carrying Out the Invention."

[0126] 1. Production of Brazing Materials Examples 1 to 24 and Comparative Examples 1 to 10 Brazing materials were obtained according to the formulations shown in Tables 1 to 3.

[0127] More specifically, according to the formulations shown in Tables 1 to 4, a fluoride-based flux, a solidifying agent, and an amine compound or a non-amine compound were charged into a kneader (2P-1, manufactured by Primix Corporation) heated to 60°C, and mixed at 100 rpm for 20 minutes. The resulting mixture was then cooled to 25°C and confirmed to be solid. This resulted in a brazing material.

[0128] 2. Evaluation (1) Coatability (Agglomeration) 20 parts by mass of brazing material was heated to 60°C and melted. Separately, 80 parts by mass of 1,8-nonanediol was heated to 60°C and melted. Next, the molten brazing material and 1,8-nonanediol were mixed. Thereafter, 1 g of the resulting mixture was sampled and dropped into a grind meter (manufactured by Erichsen) to confirm the size of the agglomerated particles. Then, the coatability (agglomeration) was evaluated according to the following criteria.

[0129] ⊚: The particle size of the aggregated particles was 30 μm or less. ○: The particle size of the aggregated particles was more than 30 μm and 40 μm or less. Δ: The particle size of the aggregated particles was more than 40 μm and 50 μm or less. ×: The particle size of the aggregated particles was more than 50 μm.

[0130] (2) Coating Properties (Uniform Coating Film) The brazing material was heated to 60° C. and melted. Next, the molten brazing material was stirred and charged into a spray coater (a spraying device, manufactured by Musashi Engineering Co., Ltd.).

[0131] The melted brazing material was applied to the substrate using a spray applicator, adjusting the liquid feed pressure so that the amount of application was 250 mg, with the temperature adjusted to 80°C, the stroke adjusted to 2.5 rotations, and the spray time adjusted to 0.08 seconds.

[0132] Thereafter, the obtained coating film was observed, and the maximum Feret diameter of the largest droplet was measured in accordance with JIS Z 8827 (2008). Then, the coating properties (uniformity) were evaluated according to the following criteria.

[0133] ◎: The maximum Feret diameter of the droplets at the time of application was 40 μm or less. ○: The maximum Feret diameter of the droplets at the time of application was more than 40 μm and not more than 60 μm. ○-: The maximum Feret diameter of the droplets at the time of application was more than 60 μm and not more than 80 μm. △: The maximum Feret diameter of the droplets at the time of application was more than 80 μm and not more than 100 μm. ×: The maximum Feret diameter of the droplets at the time of application was more than 100 μm.

[0134] (3) Hard Cake Resistance 40 g of brazing material was heated to 60°C and melted. Next, the molten brazing material was stirred and poured into a 50 ml sample tube, and allowed to stand at 80°C for 16 hours. Thereafter, the molten brazing material was subjected to a compression test using a rheometer (MCR301 manufactured by Anton Paar, measuring jig P-25). Then, the thickness of the sedimentation layer with a hardness of 50 N or more was confirmed, and the hard cake resistance was evaluated according to the following criteria.

[0135] Good: The thickness of the hard cake layer was 3% or less of the total liquid. Good-: The thickness of the hard cake layer was more than 3% but not more than 5% of the total liquid. Fair: The thickness of the hard cake layer was more than 5% but not more than 10% of the total liquid. Fair-: The thickness of the hard cake layer was more than 10% but not more than 15% of the total liquid. Bad: The thickness of the sedimentation layer was more than 15% of the total liquid.

[0136] (4) Brazeability The brazing material was heated to 80° C. and melted. Then, the molten brazing material was stirred and charged into a spray coater (a spraying device, manufactured by Musashi Engineering Co., Ltd.).

[0137] Using a spray applicator, the coating amount was 100 g / m ２ The liquid feed pressure was adjusted so that the melted brazing material was applied to an aluminum member (A1050 50 mm x 25 mm x 0.8 mm). The temperature was adjusted to 80°C, the stroke was adjusted to 2.5 rotations, and the spray time was adjusted to 0.08 seconds. Test specimens were prepared in this manner.

[0138] Thereafter, the test pieces were preheated at 250°C in an air atmosphere using a brazing furnace (box-type electric furnace, A(V)-DC-M, manufactured by Noritake TGF Co., Ltd.), and then heated to 600°C in a nitrogen gas atmosphere (oxygen concentration 100 ppm or less) for brazing.

[0139] Then, discoloration of the brazed portion was visually confirmed, and the brazability was evaluated according to the following criteria.

[0140] ◯: Almost no black color was observed. Δ: Black color was observed in part of the coated area. ×: Black color was observed over the entire coated area.

[0141]

[0142]

[0143]

[0144]

[0145] Details of the abbreviations in the table are as follows: K-Al-F flux: Product name FL7-SS, manufactured by Morita Chemical Co., Ltd. Paraffin wax: Product name Paraffin Wax-115, manufactured by Nippon Seiro Co., Ltd.

[0146] REFERENCE SIGNS LIST 1 Heat exchanger 2 Plate-joined tube 3 Tube stack 4 Refrigerant supply / discharge pipe 5 Plate member

[0147] The above invention is provided as an exemplary embodiment of the present invention, but it is merely an example and should not be interpreted as being limiting. Modifications of the present invention that are obvious to those skilled in the art are intended to be included in the scope of the following claims.

[0148] The brazing material, brazed member, and method for manufacturing a brazed member of the present invention are suitably used in heat exchangers including aluminum or an aluminum alloy.

Claims

1. A brazing material for brazing aluminum or an aluminum alloy, comprising: a fluoride-based flux; a solidifying agent; and an amine compound; the brazing material is solid at 25°C; the solidifying agent contains a normal dialcohol having 6 to 10 carbon atoms; and the amine compound contains a compound containing a secondary amino group.

2. The brazing material according to claim 1, wherein the ClogP value of the secondary amino group-containing compound is -1.85 to 5.

00.

3. The brazing material according to claim 1, wherein the content of the amine compound is 3 to 5,000 parts by mass per 100 parts by mass of the fluoride-based flux.

4. A brazed member comprising: aluminum or an aluminum alloy; and a coating formed by applying the brazing material according to claim 1 to said aluminum or said aluminum alloy.

5. A heat exchanger comprising a joint of the brazed members according to claim 4.

6. A method for manufacturing a brazed member, comprising: a processing step of processing a base material made of aluminum or an aluminum alloy; and a coating step of heating and melting the brazing material according to claim 1, supplying it to a spraying device, and spraying it onto the base material.

7. A method for manufacturing a brazed member, comprising: a processing step of processing a base material made of aluminum or an aluminum alloy; and an application step of heating and melting the brazing material according to claim 1, supplying it to an extrusion device, and extruding it onto the base material.

8. A method for manufacturing a brazed member, comprising: a processing step of processing a base material made of aluminum or an aluminum alloy; and an application step of applying the brazing material according to claim 1 to the base material by rubbing.

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