JP2011131247A - Composition for brazing aluminum - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure the excellent appearance of the composition for aqueous aluminum brazing after the brazing without impairing the solubility in water during the saponification. <P>SOLUTION: The composition for the aqueous aluminum brazing contains (A) water-soluble saponified substance of methacrylic ester-based polymer, (B) non-reactive flux, (C) water-soluble alcohol, and (D) water. The acid value of the polymer (A) is 1-19. The content (in terms of solid content) of the component (A) is 3-15 wt.%, and that of the component (B) is 25-50 wt.%, that of the component (C) is 35-55 wt.%, and that of the component (D) is 5-15 wt.%. In order to adjust the blending ratio of water-soluble alcohol to be higher while setting the acid value of a binder resin to be lower, water solubility after the saponification is guaranteed, and the appearance after the brazing is ensured. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention provides a water-based aluminum brazing composition that is excellent in appearance after brazing and that can ensure good brazing properties, stability over time, adhesion, and the like.

  Conventionally, for example, when brazing a member made of aluminum or an aluminum alloy used in an aluminum heat exchanger for automobiles represented by an evaporator, a condenser or the like mounted on a vehicle, a brazing flux or a flux is used. In addition to the material, a binder for evenly adhering to the joint was mixed, applied to the brazed part, assembled, and brazed under heating.

When a methacrylate ester polymer is used as a binder resin for an aluminum brazing composition, for example, it is superior in thermal decomposability and brazing properties compared to an acrylate ester polymer, and has adhesion, peel resistance, and blocking resistance. Properties and solvent resistance are also good.
Accordingly, the following is a conventional technique for a water-based aluminum brazing composition obtained by diluting a mixture of a flux and a water-soluble alcohol or a brazing material with water using a methacrylic ester polymer as a binder. Street.

(1) Patent Document 1
For the purpose of improving wettability, adhesion, brazing, etc. to aluminum materials (paragraph 6), a methacrylate polymer having an acid value (during drying) of 20 to 80 and a predetermined glass transition temperature is used as a binder. An aqueous aluminum brazing composition containing an alcohol and water having a flux and a flash point of 30 ° C. or higher, or further containing a brazing material is disclosed (claims 1 to 3).
In the binder preparation example 1 (paragraph 32) of the same document 1, the acid value of the binder resin is 25, and in the paint preparation example (paragraph 42), 10 parts of saponified binder and 90 parts of flux are mixed and isopropyl alcohol is mixed. 10-20 parts of alcohol such as (IPA) is added and diluted with water (Table 1).

(2) Patent Document 2
A composition for brazing aluminum using a methacrylic acid ester polymer as a binder, with the aim of improving adhesion, brazing properties, etc. (paragraph 10).
The above polymer can be dissolved in an organic solvent (paragraph 19) such as IPA, 1-propanol, ethylene glycol monoethyl ether, and flux powder (or brazing powder) can be added and applied to the aluminum material. Disclosed (Claims 3-4).
As the polymer, homopolymers of methacrylic acid esters and copolymers of the esters are listed in Table 1.

(3) Patent Document 3
Disclosed is a binder for brazing made of a methacrylic acid ester polymer having an acid value (during drying) of 1 to 100 as a main component and adding a specific subcomponent such as an oxirane group-containing resin to make it thermosetting or photocurable. (Claims 1 to 6).
In Example 1 (paragraph 42), a resin solution having an acid value of 40 is saponified with dimethylaminoethanol, and then an oxirane group-containing resin is blended. In Example 5 (paragraph 48), 2-hydroxyethyl methacrylate is blended with a resin solution having an acid value of 15.
In the preparation of the sample (brazing composition) (paragraph 55), 10 parts of binder and 90 parts of flux are mixed, and a diluent solvent is added to form an aluminum brazing composition having a solid content of 50%.

(4) Patent Document 4
An aluminum brazing composition in which water-dispersible cationic polymer fine particles and a flux are dispersed in water is disclosed (claim 1).
The cationic polymer fine particles are obtained by emulsion polymerization of a polymerizable monomer ((meth) acrylate monomer, styrene, (meth) acrylamide, etc .; paragraph 26) in the presence of a cationic polymer emulsifier (paragraph 16). 25). In Production Example 1 (paragraph 37), styrene, (meth) acrylic acid ester or the like is used as the monomer, and no unsaturated carboxylic acid is used.
Moreover, when Example 1 of a composition is seen (paragraph 40), alcohol is not included and it is thought that the applicability | paintability to the member which consists of aluminum or an aluminum alloy is not good.

(5) Other patent documents 5-7
Patent Documents 5 to 7 are prior art documents relating to an aluminum brazing composition having a methacrylate polymer as a binder.
In the synthesis example (paragraphs 30 to 35) of the resin binder of Patent Document 5 above, the acid value is unknown, and in Example 1 of the brazing composition, 9 parts of the resin binder, 91 parts of flux, 33 parts of alcohol, 4 of water Part.
The acid value of the resin binder of Patent Document 6 is 40 (paragraph 28), and the acid value of the resin binder of Patent Document 7 is about 25 (paragraph 35).

JP 2000-153393 A JP-A-11-239869 JP 2000-000687 A JP 2007-175746 A JP 2009-208129 A JP 2009-142870 A JP 2008-207237 A

In the case of a methacrylic ester-based resin binder, when the acid value is too low, the function as a binder (for example, adhesion) is lowered or the solubility in water is deteriorated during saponification. In Cited Document 1, the acid value is adjusted to a range of 20-80.
However, as the acid value of the methacrylic acid ester polymer increases, the thermal decomposability at the time of brazing is impaired, and carbides are likely to remain, and blackening due to the resin residue is observed. There is a problem that the appearance afterwards deteriorates. In addition, when blackening occurs, the fillet length also deteriorates, and the brazing property also deteriorates.
In addition, when brazing a heat exchanger, recently, the space between parts has become narrower due to the compactness of the heat exchanger, which means that the work is performed in a closed space, so that the binder resin is more difficult to thermally decompose. .
Therefore, it is conceivable to adjust the acid value of the binder resin to ensure the appearance after brazing, but as described above, the solubility in water during saponification decreases, and in order to compensate for this, organic In the case of using a solvent, there is a risk of ignition or explosion during use, which causes problems in terms of occupational health and work environment.

  This invention makes it a technical subject to ensure the external appearance after brazing in the composition for water-system aluminum brazing, without impairing the solubility to water at the time of saponification.

  As a result of diligent research to improve the appearance after brazing while ensuring the solubility of the binder resin in water smoothly, the present inventors affect the acid value of the binder resin. Therefore, by adjusting the acid value to a predetermined low range to suppress the generation of carbides during brazing, the amount of water-soluble alcohol is increased, and the content of other components is also mutually adjusted, so that the water of the binder resin The present invention was completed by discovering that a water-based brazing composition can be smoothly produced by making up for the lack of solubility in water.

That is, the present invention 1 includes (A) a water-soluble saponified product of a methacrylate ester polymer,
(B) a non-reactive flux;
(C) a water-soluble alcohol;
(D) In an aqueous aluminum brazing composition containing water,
The acid value of the polymer (A) is 1 to 19,
And the content (in terms of solid content) of the component (A) is 3 to 15% by weight, the component (B) is 25 to 50% by weight, the component (C) is 35 to 55% by weight, and the component (D) is A water-based aluminum brazing composition characterized by being 5 to 15% by weight.

The present invention 2 comprises (a) a water-soluble saponified product of a methacrylate ester polymer,
(b) a non-reactive flux;
(c) brazing material;
(d) a water-soluble (volatile) alcohol;
(e) in an aqueous aluminum brazing composition containing water,
The acid value of the polymer (a) is 1 to 19,
And the content (in terms of solid content) of the component (a) is 3 to 10% by weight, the component (b) is 25 to 40% by weight, the component (c) is 5 to 15% by weight, and the component (d) is An aqueous aluminum brazing composition comprising 35 to 55% by weight and component (e) of 5 to 15% by weight.

Invention 3 is the invention 1 or 2, wherein the polymer of component (A) or component (a) is a C ₁ -C ₁₂ alkyl ester of methacrylic acid and an unsaturated carboxylic acid, or further a hydroxyl group-containing methacrylic acid. A water-based aluminum brazing composition characterized by being a copolymer with an ester.

  In the present invention 4, the aqueous aluminum brazing composition according to any one of the present inventions 1 to 3 is applied to an aluminum member to supply flux or flux and brazing material, and brazing is performed between the aluminum member of the other party. This is a method of brazing aluminum.

First, in Patent Document 1 described above, the acid value of the binder resin is 20 to 80, but in the present invention, the acid value of the binder resin is set to be lower than 19 and the water-soluble saponified product (binder) is first used. By adjusting the content ratios of water-soluble alcohol, flux, water, or brazing material to each other, it is possible to prevent blackening after brazing and to ensure a good appearance.
In addition, by increasing the amount of water-soluble alcohol, the solubility in water after saponification is compensated, the production of the composition is facilitated, and the content of each component of the composition is adjusted to each other. Adhesiveness, adhesive coating property, or storage stability of the composition itself can be secured satisfactorily.

The present invention firstly includes a water-soluble saponified product of a methacrylic acid ester polymer, a non-reactive flux, a water-soluble alcohol, and water, or further contains a brazing material. The aqueous acid brazing composition has a low acid value of 1 to 19 and the contents of the components below the polymer are adjusted to each other within an appropriate range. Second, these aqueous compositions This is a brazing method using
The aluminum of the present invention is a concept including both pure aluminum and aluminum alloy.

The binder component of the present invention is for adhering the flux to the aluminum member, and from the standpoint of preventing thermal brazing failure due to good thermal decomposability, a methacrylic ester polymer is selected, and a water-soluble saponified product is used. Used in form.
It is essential that the acid value (when dried) of the methacrylic acid ester polymer of the present invention (component (A) in the present invention 1 and component (a) in the present invention 2) is 1 to 19, preferably Is 5-18. When the acid value exceeds the upper limit of 19, there is a concern that the appearance may be poor after brazing. When the acid value is lower than the lower limit of 1, the solubility in water decreases.

In this methacrylic acid ester polymer, the constituent monomer is not particularly limited. However, as shown in the present invention 3, a C ₁ -C ₁₂ alkyl ester of methacrylic acid and an unsaturated carboxylic acid, or further a hydroxyl group is contained. Copolymers with methacrylic acid esters are preferred.
As the C ₁ -C ₁₂ alkyl ester of methacrylic acid, at least one monomer component represented by the following general formula (1) can be used. When a long-chain alkyl ester having more than 12 carbon atoms is used, the water-solubility of the methacrylic acid ester-based copolymer is lowered, which adversely affects brazing properties.
CH ₂ = C (CH ₃ ) COOR (1)
(In the formula (1), R is an alkyl group having 1 to 12 carbon atoms.)
Specific examples of the C ₁ -C ₁₂ alkyl ester of methacrylic acid include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, And uraryl methacrylate.
The unsaturated carboxylic acid is used from the standpoint of maintaining water solubility, and acrylic acid, methacrylic acid, (anhydrous) maleic acid, fumaric acid, itaconic acid, (anhydrous) citraconic acid, or salts thereof can be used alone or Can be used together.

Moreover, the said methacrylic acid ester-type polymer can contain a hydroxyl-containing methacrylic acid ester in a constituent monomer other than the said monomer component from the viewpoint which increases the adhesiveness to an aluminum member. Examples of the hydroxyl group-containing methacrylic acid ester include hydroxyl group-containing monomers represented by the following general formulas (2) to (4), and at least one of these can be used.
CH ₂ = C (CH ₃ ) COO (CH ₂ ) _n OH (2)
(In formula (2), n is an integer of 2 or more and 4 or less.)
_{CH 2 = C (CH 3)} COO (C 2 H 4 O) n H ... (3)
(In formula (3), n is an integer of 2 or more and 12 or less.)
CH ₂ = C (CH ₃ ) COO (C ₃ H ₆ O) _n H (4)
(In formula (4), n is an integer of 2 or more and 12 or less.)
Specific examples of the hydroxyl group-containing methacrylic acid ester include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycolic methacrylate ester (n = 2 to 12 in the above general formula (3)), and the like.
Further, since the homopolymer of C ₁ -C ₁₂ alkyl ester of methacrylic acid is brittle and has low adhesion to the aluminum member, and the lower limit of the acid value of the binder component is 1, it is preferable to select the copolymer. .

The methacrylic acid ester copolymer is obtained by radical polymerization by a known polymerization method such as bulk polymerization, solution polymerization, suspension polymerization or the like.
In particular, it is preferable to obtain various polymers by a solution polymerization method using alcohol as a solvent.
The methacrylic acid ester polymer is saponified with a cationic compound in an aqueous solution to make it water-soluble.
Examples of the cationic compound include ammonia, diethylamine and triethylamine, and volatile amino alcohols such as dimethylaminoethanol are suitable.
The binder content of the water-soluble saponified methacrylic acid ester polymer is preferably about 5 to 80% by weight, more preferably 10 to 55% by weight.

The non-reactive flux of the present invention (component (B) in the present invention 1, component (b) in the present invention 2) contains a fluoride-based flux as a main component, and any of them can be used without limitation within this range.
Specific examples of the non-reactive flux include potassium fluoroaluminate, potassium fluoride, aluminum fluoride, lithium fluoride, sodium fluoride, potassium fluoroaluminate-cesium complex, cesium fluoroaluminate, and the like. Potassium aluminate is preferred. Accordingly, reactive zinc-substituted fluxes such as potassium fluorozincate and cesium fluorozincate are excluded from the flux of the present invention.
Commercial products of non-reactive flux include Nocolok Flux (potassium fluoroaluminate) and Nocolok Cs Flux (cesium-based flux) manufactured by Solvay.

In the aqueous aluminum brazing composition of the present invention, by adding a water-soluble and volatile alcohol (component (C) in the present invention 1, component (d) in the present invention 2) to the composition, By reducing the surface tension of the coating material, the wettability of the coating material to the aluminum member can be improved, and the water repelling phenomenon can be suppressed and uniformly applied. In this case, it is preferable to use alcohol with a flash point of 30 ° C or higher from the standpoint of suppressing dangers such as ignition and explosion. For alcohol with a high flash point, the surface tension of the coating film is further reduced by adding a small amount. There is also an advantage.
Specific examples of the alcohol having a flash point of 30 ° C. or higher include ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol butyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether. , Propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, 1,3 butanediol, 3-methyl-1,3-butanediol, 3-methoxy-3-methyl- Examples include 1-butanol.
However, the present invention does not exclude water-soluble alcohols having a flash point of less than 30 ° C. such as methanol, ethanol, and IPA.

Moreover, in the composition for water-system aluminum brazing of this invention, in addition to the essential component of a flux, a binder, water-soluble alcohol, and water, a brazing material can be contained.
Examples of the brazing material (component (c) in the present invention 2) include metal silicon powder, silicon-aluminum alloy, or an alloy containing a small amount of magnesium, copper, germanium, or the like. An example of a commercially available brazing material is Silgrain (from Elkem), and an example of a mixture of flux and brazing material is Nocolok Sil Flux (a mixture of potassium fluoroaluminate and metal silicon powder) from Solvay. .

As described above, the water-based aluminum brazing composition of the present invention 1 includes (A) a water-soluble saponified product of a methacrylic ester polymer, (B) a non-reactive flux, (C) a water-soluble alcohol, (D) contains water.
In the present invention 1, the content (solid content conversion) of the component (A) in the composition needs to be 3 to 15% by weight, and preferably 5 to 10% by polymerization. Since the water-soluble saponified product of the polymer is an important factor for the appearance after brazing, the appearance after brazing deteriorates when the content exceeds the upper limit (15% by weight). When the content is lower than the lower limit (3% by weight), the adhesion is deteriorated and the coating property (handling property) is lowered.
The content (in terms of solid content) of the non-reactive flux (B) needs to be 25 to 50% by weight, and preferably 30 to 45% by weight. If the content of the flux exceeds the upper limit (50% by weight), the coating property of the composition is deteriorated and the cost is increased. If the content is lower than the lower limit (25% by weight), the function of the flux is not sufficiently exhibited, and the brazing property. Gets worse.

The content of the water-soluble alcohol (C) needs to be 35 to 55% by weight, and preferably 40 to 50% by weight. If the content exceeds the upper limit (55% by weight), the working environment deteriorates from the viewpoint of occupational health due to flammability and odor, and if the content is lower than the lower limit (35% by weight), the coating property (wetting property) of the composition deteriorates. To do. In particular, as described above, in the present invention, since the acid value of the polymer (A) is set low, the content of the water-soluble alcohol is included from the viewpoint of supplementing the solubility of the polymer in water after saponification. The amount needs to be set to a large value of 35% by weight or more.
In addition, the addition of water maintains the work environment in terms of occupational health and serves to avoid the flammability of the composition. The content of water (D) is required to be 5 to 15% by weight, and preferably 8 to 12% by weight. If the water content exceeds the upper limit (15% by weight), the storage stability of the composition is impaired because the acid value at the time of drying the binder resin is low. Moreover, when content is lower than a minimum (5 weight%), as above-mentioned, flammability, an odor, etc. will increase and workability | operativity in terms of occupational health will deteriorate.
The brazing composition is adjusted so that the total solid content concentration and viscosity by dilution of water are within an appropriate range. The solid content concentration of the entire composition by dilution of water is suitably 25 to 80% by weight, preferably 35 to 55% by weight.

On the other hand, the brazing composition of the present invention 2 is basically a brazing composition of the present invention 1 further added with a brazing material. Therefore, (a) a water-soluble saponified product of a methacrylic ester polymer. And (b) a non-reactive flux, (c) a brazing filler metal, (d) a water-soluble alcohol, and (e) water.
In this case, the point that the acid value of the polymer (a) is set to a low value of 1 to 19 (preferably 5 to 18) is the same as that of the present invention 1.
The content of the component (a) (in terms of solid content) is 3 to 10% by weight (preferably 4 to 8% by weight), and the component (b) is 25 to 40% by weight (30 to 35% by weight). Component (c) is 5 to 15% by weight (7 to 13% by weight), Component (d) is 35 to 55% by weight (40 to 50% by weight), and Component (e) is 5 to 15% by weight (8 to 12%). % By weight).
Even if the content of the brazing material (c) exceeds the upper limit (15% by weight), the quality of the brazing does not change much and the cost is wasted. If the content is lower than the lower limit (5% by weight), the brazing property is naturally deteriorated. .
The total solid content concentration when diluted with water is suitably 20 to 80% by weight, preferably 30 to 60% by weight.

In brazing using the aqueous brazing composition of the present invention, a brazing composition is applied to an aluminum member, a flux (or flux and brazing material) is supplied, and the aluminum member has a predetermined structure. After assembly, the basic principle is to braze between the coated aluminum member and the mating member by heating to a brazing temperature (see the present invention 4).
When assembling the aluminum member, the brazing composition of the present invention 1 containing no brazing material is applied to one aluminum member and assembled with the other aluminum member (brazing sheet clad with the brazing material). Will be brazed. Moreover, when the brazing composition contains a brazing material as in the present invention 2, the mating material is an aluminum member without a brazing material (bearing material).
There is no restriction | limiting in particular in the coating method of the brazing composition of this invention, Arbitrary methods can be applied including a roll coat method, a dipping method, a spray method, etc.
However, the above-mentioned dipping method may make it difficult to apply a brazing composition having a constant composition ratio at a high speed due to precipitation of the flux. Since there is a problem such as clogging of the gun, a roll coat method in which an aqueous brazing composition is applied to an aluminum member with a roll coater is preferable.
In the roll coating method, the aqueous brazing composition of the present invention is applied to the surface of the aluminum member before the member is assembled into an arbitrary structure in advance (that is, when the member is in a plate-like or planar state). Since the brazing can be performed by supplying the required amount in a required amount uniformly and efficiently, there is an advantage that productivity is increased by adopting this pre-coating method.

In applying the aqueous brazing composition of the present invention, the adhering amount (dry weight) of the composition is suitably 3 to 100 g / m ² from the balance of brazing property and coating stability, preferably 5 ˜20 g / m ² .
In the above brazing method, the aluminum member is assembled into a predetermined structure, and then brazed by heating to a brazing temperature in a nitrogen atmosphere. In the present invention, a methacrylate polymer is used as the binder resin. And in order to keep the acid value of the polymer low, the polymer is depolymerized in a short time at a temperature lower than the normal brazing temperature (about 600 ° C.) to become a volatile monomer. The binder disappears at the time of brazing, and the binder and its carbide are prevented from remaining in the brazed portion, and the appearance after brazing is excellent while performing stable brazing.

Examples of Synthesis of Methacrylic Acid Ester Copolymer (Binder Resin), Examples of Compositions for Aqueous Aluminum Brazing of the Present Invention Using Copolymers Obtained in Synthesis Examples, Water Systems Obtained in Examples Various evaluation test examples such as appearance after brazing, brazing property, adhesion, and storage stability of the brazing composition will be sequentially described. “Parts” and “%” in the examples are basically based on weight.
The present invention is not limited to the following examples and test examples, and it is needless to say that arbitrary modifications can be made within the scope of the technical idea of the present invention.

<< Synthesis example of methacrylate ester copolymer >>
Among Synthesis Examples 1 to 3 below, Synthesis Example 1 is an example of a methacrylic acid copolymer having an acid value of about 3, Synthesis Example 2 is also an example having an acid value of about 15, and Synthesis Example 3 has an acid value of about 15 examples.
Comparative Synthesis Example 1 is an example of a copolymer having an acid value exceeding the upper limit (19) of the appropriate range of the present invention (in other words, a reference example of the copolymer described in Patent Document 1 described above).
(1) Synthesis example 1
After charging 169 parts of IPA in a reaction apparatus equipped with a stirrer, a cooling pipe, a dropping funnel and a nitrogen introducing pipe, the temperature was raised until the system temperature reached 80 ° C. under a nitrogen stream. Next, a mixed solution of 31 parts of methyl methacrylate, 31 parts of 2-hydroxyethyl methacrylate, 87 parts of isobutyl methacrylate, 0.7 part of methacrylic acid and 4 parts of benzoyl peroxide was dropped into the system over about 3 hours, Furthermore, the temperature was kept at the same temperature for 10 hours to complete the polymerization, and a binder having an acid value of about 3 at the time of drying was obtained.
Next, 113 parts by weight of the above solution, 90 parts of 3-methoxy-3-methyl-1-butanol (with a flash point of 30 ° C. or higher) were added to a reactor equipped with a stirrer, a vapor agglomeration remover, and a nitrogen introduction tube. Alcohol), 33 parts of ion-exchanged water and 0.3 part of dimethylaminoethanol were charged, and the temperature was raised until the system was refluxed under a nitrogen stream. 60 parts of IPA in the system was removed using a vapor agglomeration removing apparatus to obtain an aluminum brazing binder (water-soluble saponified product of methacrylate ester copolymer) having a solid content of 30%.

(2) Synthesis example 2
After charging 169 parts of IPA in a reaction apparatus equipped with a stirrer, a cooling pipe, a dropping funnel and a nitrogen introducing pipe, the temperature was raised until the system temperature reached 80 ° C. under a nitrogen stream. Next, a mixed solution of 31 parts of methyl methacrylate, 31 parts of 2-hydroxyethyl methacrylate, 84 parts of isobutyl methacrylate, 3.5 parts of methacrylic acid and 4 parts of benzoyl peroxide was dropped into the system over about 3 hours, Furthermore, the temperature was maintained at the same temperature for 10 hours to complete the polymerization, and a binder having an acid value of about 15 at the time of drying was obtained.
Next, a reaction apparatus equipped with a stirrer, a vapor coagulation removal apparatus, and a nitrogen inlet tube was charged with 113 parts of the above solution, 90 parts of 3-methoxy-3-methyl-1-butanol, 33 parts of ion-exchanged water, and 1 After charging 2 parts of dimethylaminoethanol, the temperature was raised until the system was refluxed under a nitrogen stream. 60 parts of IPA in the system was removed using a vapor agglomeration removing apparatus to obtain an aluminum brazing binder (water-soluble saponified product of methacrylate ester copolymer) having a solid content of 30%.

(3) Synthesis example 3
After charging 169 parts of IPA in a reaction apparatus equipped with a stirrer, a cooling pipe, a dropping funnel and a nitrogen introducing pipe, the temperature was raised until the system temperature reached 80 ° C. under a nitrogen stream. Next, a mixed solution of 32 parts of methyl methacrylate, 31 parts of 2-hydroxyethyl methacrylate, 83 parts of isobutyl methacrylate, 4.4 parts of methacrylic acid and 4 parts of benzoyl peroxide was dropped into the system over about 3 hours, Further, the temperature was kept at the same temperature for 10 hours to complete the polymerization, and a binder having an acid value of about 19 at the time of drying was obtained.
Next, in a reactor equipped with a stirrer, a vapor coagulation removal device and a nitrogen introduction tube, 113 parts of the above solution, 89 parts of 3-methoxy-3-methyl-1-butanol, 33 parts of ion-exchanged water and 1 After charging 0.5 parts of dimethylaminoethanol, the temperature was raised until the system was refluxed under a nitrogen stream. 60 parts of IPA in the system was removed using a vapor agglomeration removing apparatus to obtain an aluminum brazing binder (water-soluble saponified product of methacrylate ester copolymer) having a solid content of 30%.

(4) Comparative synthesis example 1
After charging 169 parts of IPA in a reaction apparatus equipped with a stirrer, a cooling pipe, a dropping funnel and a nitrogen introducing pipe, the temperature was raised until the system temperature reached 80 ° C. under a nitrogen stream. Next, a mixed solution of 31 parts of methyl methacrylate, 30 parts of 2-hydroxyethyl methacrylate, 83 parts of isobutyl methacrylate, 5.6 parts of methacrylic acid and 4 parts of benzoyl peroxide was dropped into the system over about 3 hours, Furthermore, the temperature was kept at the same temperature for 10 hours to complete the polymerization, and a binder having an acid value of about 25 at the time of drying was obtained.
Next, a reaction apparatus equipped with a stirrer, a vapor coagulation removal apparatus, and a nitrogen inlet tube was charged with 113 parts of the above solution, 90 parts of 3-methoxy-3-methyl-1-butanol, 33 parts of ion-exchanged water, and 1 After charging 9.9 parts of dimethylaminoethanol, the temperature was raised until the system was refluxed under a nitrogen stream. 60 parts of IPA in the system was removed using a vapor agglomeration remover to obtain an aluminum brazing binder (methacrylate ester water-soluble saponified product) having a solid content of 30%.

Therefore, the aqueous aluminum brazing composition of the present invention was manufactured using each binder (water-soluble saponified product of a methacrylate ester copolymer) obtained in Synthesis Examples 1 to 3 and Comparative Synthesis Example 1. .
<< Examples of water-based aluminum brazing composition >>
Of the following Examples and Comparative Examples, Examples 1A to 9A and Comparative Examples 1A to 13A belong to Group A, which contains no brazing material and is an example of a brazing composition containing a flux and a binder. Group B to which 1B to 9B and Comparative Examples 1B to 13B belong is an example of a brazing composition containing a brazing material in addition to a flux and a binder.
Among the above Examples 1A to 9A, Examples 1A to 3A are examples in which the binder resin, flux, water-soluble alcohol, and water content are fixed to change the acid value of the binder resin. Examples 4A to 6A and The same applies to Examples 7A to 9A. In particular, Examples 3A, 6A, and 9A are examples in which the acid value of the binder is set to the upper limit (19) of the appropriate range of the present invention.
Among Comparative Examples 1A to 13A, Comparative Examples 1A to 4A are examples in which the binder content is less than the lower limit (3%) of the proper range of the present invention, and Comparative Examples 8A to 11A are upper limits in which the binder content is the same range (3%). 15%), Comparative Example 12A is an example in which the content of water-soluble alcohol is less than the lower limit (35%) of the appropriate range of the present invention, and Comparative Example 13A has an upper limit of water content in the present invention (35%). 15%), Comparative Examples 4A to 7A and 11A are examples in which the acid value of the binder resin exceeds the appropriate range of the present invention (particularly, Comparative Examples 5A to 7A are suitable for the entire composition of the composition in accordance with the present invention). In this example, only the acid value is not compatible with the present invention.
On the other hand, also in Examples 1B to 9B and Comparative Examples 1B to 13B including the brazing material, the meanings of the corresponding numbers are the same as in the examples of Group A and the comparative examples. For example, Examples 1B to 3B are examples in which the binder, flux, water-soluble alcohol, and water content were fixed and the acid value of the binder was changed, as in Examples 1A to 3A, and Comparative Examples 5B to 5B. 7B is an example in which the entire composition of the composition is compatible with the present invention, but only the acid value is not compatible with the present invention, as in Comparative Examples 5A to 7A.
The upper half of FIGS. 1 to 2 summarizes the composition of the aqueous aluminum brazing composition. However, FIG. 1 shows each composition of the A group, and FIG. 2 shows each composition of the B group.

(1) Example 1A
The acid value at the time of drying obtained in Synthesis Example 1 was about 3, and the solid content was 34% (10 parts in terms of solid content), 35 parts of potassium fluoride fluoride-based flux, and 3 parts of water. And 28 parts of 3-methoxy-3-methyl-1-butanol as a water-soluble alcohol were added and diluted to obtain an aqueous aluminum brazing composition having a solid concentration of 45%.
In addition, about the said water-soluble alcohol, it replaced with 3-methoxy-3-methyl- 1-butanol, and even if it used various alcohol with the above-mentioned boiling point of 30 degreeC or more, it could be used without a problem (other examples) And the comparative example was the same).

(2) Example 2A
The acid value at the time of drying obtained in Synthesis Example 2 is about 15, 34 parts of binder (30 parts in terms of solid content) having a solid content of 30%, 35 parts of potassium aluminate fluoride flux, 3 parts of water And 28 parts of 3-methoxy-3-methyl-1-butanol were added to dilute to obtain an aqueous aluminum brazing composition having a solid content concentration of 45%.

(3) Example 3A
The acid value at the time of drying obtained in Synthesis Example 3 is about 19 and the solid content is 34% (10 parts in terms of solid content), 35 parts of potassium aluminate fluoride flux and 3 parts of water. And 28 parts of 3-methoxy-3-methyl-1-butanol were added to dilute to obtain an aqueous aluminum brazing composition having a solid content concentration of 45%.

(4) Examples 4A-9A
The composition shown in FIG. 1 is based on Example 1A, using each binder having an acid value of about 3, 15, 19 and a solid content of 30% obtained in Synthesis Examples 1-3. A water-based aluminum brazing composition was produced.

(5) Comparative Example 1A
9 parts of water was added to 3 parts of binder (1 part in terms of solids) having a dry acid value of about 3 and a solid content of 30% obtained in Synthesis Example 1 above, and 35 parts of potassium fluoride fluoride fluoride flux. And 52 parts of 3-methoxy-3-methyl-1-butanol were added to dilute to obtain an aqueous aluminum brazing paint having a solid content of 36%.

(6) Comparative Examples 2A-13A
Based on the above Comparative Example 1A, using each binder having an acid value of about 3, 15, 19 and 25 in the dry synthesis obtained in Synthesis Examples 1 to 3 and Comparative Synthesis Example 1 and having a solid content of 30%. The composition for water-system aluminum brazing was manufactured with the composition shown in FIG.

(7) Example 1B
17 parts of binder (5 parts in terms of solid content) having a dry acid value of about 3 and a solid content of 30% obtained in Synthesis Example 1, 32 parts of a potassium fluoride aluminate flux, a brazing material 8 parts of metal silicon powder as a mixture, diluted by adding 7 parts of water and 36 parts of water-soluble alcohol 3-methoxy-3-methyl-1-butanol, and a solid content concentration of 45% for aluminum brazing I got a thing.

(8) Examples 2B-9B
Using each binder having an acid value of about 15 and 19 and a solid content of 30% obtained in Synthesis Examples 2 to 3 based on Example 1B, water-based aluminum having the composition shown in FIG. A brazing composition was produced.

(9) Comparative Example 1B
3 parts of binder having a dry acid value of about 3 and a solid content of 30% (1 part in terms of solid content) obtained in Synthesis Example 1 above, 36 parts of potassium aluminate fluoride flux, brazing material 8 parts of metal silicon powder as a mixture, 9 parts of water and 43 parts of 3-methoxy-3-methyl-1-butanol were added to dilute, and an aqueous aluminum brazing composition having a solid content concentration of 45% was obtained. Obtained.

(10) Comparative Examples 2B-13B
Based on the above Comparative Example 1B using each binder having an acid value of about 3, 15, 19 and 25 in the drying obtained in Synthesis Examples 1 to 3 and Comparative Synthesis Example 1 and having a solid content of 30%. The composition for water-system aluminum brazing was manufactured with the composition shown in FIG.

<< Example of performance evaluation test of aqueous aluminum brazing composition >>
Therefore, each of the aqueous brazing compositions obtained in Examples 1A to 9A, 1B to 9B and Comparative Examples 1A to 13A and 1B to 13B was subjected to the following various evaluation tests.

First, the storage stability of the composition itself was examined before brazing with the aqueous brazing composition.
(1) Storage stability 200 g of a brazing composition was put in a 200 cc glass bottle, stored at 23 ° C. for 2 months, and the change from the initial state was visually observed to evaluate superiority or inferiority according to the following criteria.
○: The composition was uniform and no turbidity or separation was observed.
Δ: The composition was non-uniform and some turbidity was observed.
X: The composition was non-uniform, and turbidity and separation were clearly observed.

Subsequently, the test piece for brazing evaluation was created by apply | coating each aqueous brazing composition to an aluminum member.
That is, an aluminum member coated with each brazing composition is a horizontal material (JIS-A3003 alloy, 60 mm × 25 mm × 0.3 mm), and an aluminum alloy containing 1.2% manganese and 2.5% zinc. A vertical material (55 mm × 25 mm × 1.0 mm) made of a brazing sheet clad with a silicon-aluminum alloy (brazing material) or an aluminum alloy containing 1.2% manganese and 2.5% zinc is used as the horizontal material. The test piece for brazing evaluation was prepared by assembling the shape and fixing with a stainless steel wire.
Thereafter, the above test piece was heated at 605 ° C. in a nitrogen gas atmosphere (oxygen concentration of 100 ppm or less) using a brazing furnace (box electric furnace, manufactured by Noritake TCF, A (V) -DC-M). A brazing test was conducted.

And based on the result of the brazing test, the superiority or inferiority of the performance in the following various tests was evaluated.
(2) Appearance The appearance after the brazing test was visually evaluated according to the following criteria.
◯: No blackening due to acrylic resin residue was observed.
(Triangle | delta): The blackening derived from the residue of an acrylic resin was seen by a part of test piece.
X: Blackening derived from the acrylic resin residue was clearly seen in the entire test piece.

(3) Brazing property The fillet length after the brazing test was measured and evaluated by visual observation according to the following criteria.
○: A fillet of 20 mm or more on one side was formed without any problem in appearance.
Δ: Regardless of appearance problems, only fillets of 10 mm or more and less than 20 mm on one side were formed.
X: Discoloration was observed on the appearance, and the fillet was less than 10 mm or was not formed.

(4) Adhesion Using a roll coater (manufactured by Mochizuki Kiko Co., Ltd.), a brazing composition is applied to an aluminum member (JIS-A3003 alloy) so that the coating amount is 10 ± 1 g / m ^2. After drying in an oven (manufactured by TABAI ESPEC, PH-301) at 180 ° C. for 90 seconds, a pencil hardness test was performed according to JIS (K5600-5-4).
The pencil hardness becomes softer in the order of H → F → HB → B, and the higher the number added to B, the softer.
○: Adhesiveness was 5B or more.
Δ: Adhesiveness was 6B.
X: Adhesiveness was less than 6B.

(5) Coating property It was carried out whether or not the brazing composition could be uniformly coated with a roll coater (manufactured by Mochizuki Kiko Co., Ltd.) so that the coating amount was 10 ± 1 g / m ² .
A: Even if the coating operation was continued for 60 minutes or more, no variation in the coating amount was observed.
Δ: The coating amount varied ± 3 g / m ² or more within 30 minutes to 60 minutes.
X: The coating amount varied within ± 3 g / m ² within 30 minutes.

(6) Safety In order to confirm the safety of the brazing composition, the smell was actually smelled and confirmed using the odor viewpoint as a criterion.
○: Solvent odor was weak and no discomfort was observed.
Δ: The solvent odor was strong, but there was no discomfort.
X: The solvent odor was strong and the discomfort was recognized.

(7) Comprehensive evaluation Practical superiority or inferiority as a brazing composition (paint) was evaluated by combining the above various test results.
○: All evaluation items were ○.
(Triangle | delta): There existed one or more (triangle | delta) in the evaluation item of various tests.
X: There were one or more x in the evaluation items of various tests.

<< Test results of water-based aluminum brazing composition >>
The lower half of FIG. 1 shows the test results of Examples 1A to 9A and Comparative Examples 1A to 13A, and the lower half of FIG. 2 shows the test results of Examples 1B to 9B and Comparative Examples 1B to 13B.
In the following, the test results will be described with a focus on the brazing composition (paint) that does not contain the brazing material of Group A (see FIG. 1), and the paint containing the brazing material (see FIG. 2) will be described supplementarily. .
(1) First, the acid value of the copolymer constituting the binder component is larger than the upper limit (= 19) of the appropriate range of the present invention. The appearance after brazing was Δ to ×, and the brazing property was similarly Δ to ×.
On the other hand, in Examples 1A to 9A where the acid value of the copolymer was set to a low value of 3 to 19, the appearance after brazing was all good, and the evaluation of the brazing property was the same. . Moreover, in spite of a low acid value, all the applicability | paintability of Examples 1-9 was evaluation of (circle).
Thus, when Examples 1A to 9A are seen in comparison with Comparative Examples 5A to 7A, the magnitude of the acid value of the binder resin affects the appearance after brazing, and there is no blackening by keeping the acid value low. It has been found that an excellent appearance can be obtained, and that the applicability (wetting property) is also improved by adjusting the content of the water-soluble alcohol to be large.
Moreover, 1A, 4A, and 7A (both having an acid value of 3) having the lowest acid value of the copolymer in the examples had no problem in coating properties. However, if the acid value is excessively low, the solubility of the copolymer in water after saponification decreases, so in fact, the copolymer with zero acid value is inferior in applicability and practicality as a paint. There was a problem.
On the other hand, as shown in FIG. 2, the coating material containing the brazing material of Group B also had the same result as that of Group A (see Examples 1B to 9B and Comparative Examples 4B to 7B).

(2) In Comparative Examples 8A to 11A in which the binder component content exceeds the upper limit (15% by weight) of the proper range of the present invention, the appearance after brazing is still Δ to x, and the brazing property is the same. Δ to ×.
On the other hand, in Examples 1A to 9A in which the binder component content is in an appropriate range, the appearance after brazing and the evaluation of brazing properties were all good.
Thereby, when Example 1A-9A is seen in contrast with Comparative example 8A-11A, content of a binder component affects the external appearance after brazing, and there is no blackening by suppressing content to below predetermined. An excellent appearance can be obtained, and among Comparative Examples 8A to 11A, the acid value of the binder resin is the upper limit (= 19) of the proper range of the present invention, or in Comparative Examples 10A to 11A exceeding this, the appearance and brazing It was found that both sexes were evaluated as x. On the contrary, in Comparative Examples 1A to 4A in which the content of the binder component is less than the appropriate range of the present invention, the adhesiveness was lowered and the applicability was not good.
On the other hand, as shown in FIG. 2, the paint containing the brazing material of Group B also had the same result as that of Group A (see Examples 1B to 9B and Comparative Examples 8B to 11B).

(3) As described above, in Examples 1A to 9A, the acid value of the binder resin was set low, but the content of the water-soluble alcohol was adjusted so as to compensate for that, so the acid value was designed to be quite low. In spite of the above Examples 1, 4, and 7 (acid value = 3), the coating property (wetting property) was good.
Therefore, the composition of the paint and the acid value of the binder resin are compatible with the present invention. However, in Comparative Example 12 in which the content of the water-soluble alcohol is less than the lower limit (35% by weight), the applicability (wetting property) is impaired. When using a binder resin with a low acid value, it is confirmed that it is necessary to increase the solubility of the binder resin in water by increasing the amount of water-soluble alcohol in order to ensure good paint application. did it.
Although not presented as a comparative example, when the content of the water-soluble alcohol exceeded the upper limit, the odor increased, the occupational health environment deteriorated, and there was concern about the risk of ignition.
On the other hand, as shown in FIG. 2, the paint containing the brazing material of Group B also had the same result as that of Group A (see Examples 1B to 9B and Comparative Example 12B).

(4) The composition of the paint and the acid value of the binder resin are compatible with the present invention, but in Comparative Example 13A where the water content exceeds the upper limit (15% by weight) of the proper range of the present invention, the storage stability of the paint is Although deteriorated, in Examples 1A to 9A in which the water content was adapted to the present invention, the storage stability was good.
Although not presented as a comparative example, when the water content was lower than the lower limit, the odor increased and the occupational health environment deteriorated, and there was concern about the risk of ignition.
On the other hand, as shown in FIG. 2, the paint containing the brazing material of group B also had the same result as that of group A (see Examples 1B to 9B and Comparative Example 13B).
Although this B group paint was not presented as a comparative example, the brazing property deteriorated when the brazing filler metal content was too small. Moreover, even if an excessive amount of brazing material was used, there was no change in evaluation such as brazing.

(5) As seen in the above (1) to (4), in the overall evaluation of brazing, storage stability, adhesion, applicability, and odor, focusing on the appearance after brazing, Examples 1A to 9A Was excellent overall as a water-based brazing paint.
Therefore, as a brazing paint, in order to ensure good performance, especially in the appearance and other brazing, the composition of the paint should be within the appropriate range while keeping the acid value of the binder resin low. The importance of adjusting (especially increasing the amount of water-soluble alcohol) became clear.
The same was true for Group B paints.

It is the table | surface which put together the various evaluation test results, such as a composition of the composition for water-system aluminum brazing of Examples 1A-9A and Comparative Examples 1A-13A, and an external appearance, brazing property, adhesiveness. It is an equivalent figure of Drawing 1 about Examples 1B-9B and comparative examples 1B-13B.

Claims (4)

(A) a water-soluble saponified product of a methacrylate ester polymer;
(B) a non-reactive flux;
(C) a water-soluble alcohol;
(D) In an aqueous aluminum brazing composition containing water,
The acid value of the polymer (A) is 1 to 19,
And the content (in terms of solid content) of the component (A) is 3 to 15% by weight, the component (B) is 25 to 50% by weight, the component (C) is 35 to 55% by weight, and the component (D) is An aqueous aluminum brazing composition characterized by being 5 to 15% by weight. (a) a water-soluble saponified product of a methacrylate ester polymer;
(b) a non-reactive flux;
(c) brazing material;
(d) a water-soluble alcohol;
(e) In a water-based aluminum brazing composition containing water,
The acid value of the polymer (a) is 1 to 19,
And the content (in terms of solid content) of the component (a) is 3 to 10% by weight, the component (b) is 25 to 40% by weight, the component (c) is 5 to 15% by weight, and the component (d) is An aqueous aluminum brazing composition characterized by comprising 35 to 55% by weight and component (e) of 5 to 15% by weight. The polymer of component (A) or component (a) is a copolymer of a C ₁ -C ₁₂ alkyl ester of methacrylic acid and an unsaturated carboxylic acid, or further a hydroxyl group-containing methacrylic ester. The aqueous aluminum brazing composition according to claim 1 or 2.   A water-based aluminum brazing composition according to any one of claims 1 to 3 is applied to an aluminum member to supply flux or flux and brazing material, and brazing is performed between the aluminum member of the other side. An aluminum brazing method characterized by the above.

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