JPH06100877A - Lubricant composition for forming lubricating film readily removable by washing with water - Google Patents

Abstract

PURPOSE:To provide a composition which has excellent lubricity and forms a lubricating film readily removable by washing with water after molding. CONSTITUTION:This lubricant composition consists of at least one compound (a) selected from a water-soluble polyester having an average molecular weight of 30,000 or higher and lower than 500,000 and a water-soluble polysaccharide, at least one water-soluble polyamide (b), at least one wax (c) having a melting point of 50-130 deg.C, and water (d), wherein the weight ratio of component (a) to component (b) is (50:1) to (1:50) and the amount of component (c) is 3-90 pts.wt. based on 100 pts.wt. total of components (a) and (b).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricant composition which imparts excellent moldability to the surface of a metal and imparts a film which can be easily washed off with water after the molding process. A lubricant composition suitable for imparting a lubricating property that withstands high-level forming such as plastic forming, and for forming a film that can be easily dissolved and removed with water or the like from a lubricating film remaining on the metal surface after forming Regarding

[0002]

2. Description of the Related Art Metallic materials, such as steel materials, are formed into a plate shape, a tubular shape, a bar shape, etc. by a rolling machine of a steel manufacturer, etc., and further, depending on their respective applications in home appliances, automobiles, building material manufacturers, etc. It is formed by a method such as pressing and forging, and most of them form a lubricating film by combining a solid lubricant such as oil and fat and lime soap with a zinc phosphate film. The site where such molding processing is performed,
Due to oil stains and dust scattering on the molding equipment and its surroundings,
The environment is extremely poor both in terms of pollution prevention and occupational health and safety.

On the other hand, conventionally, with respect to a metal member having a complicated shape, a heavily worked portion is divided into a plurality of worked portions, and the members are assembled after molding. However, in recent years, as seen in the shapes of automobile bodies and the like, there is a tendency that a design that uses a large number of curved surfaces is used for the purpose of distinguishing the appearance, and a strong processing part having a complicated shape is formed into a plurality of parts. In the conventional method of dividing into processed parts, molding, and then joining and assembling a plurality of processed parts, the surface smoothness is impaired, resulting in a great disadvantage in productivity. Therefore, there is a strong demand for a lubricant having higher lubrication performance, improving the working environment, and not impairing the workability of the next process such as welding, pretreatment for painting, and painting. Although it has been proposed to use a wax-based lubricant as a lubricant to meet such demands, the environment in press working is improved but not as good as when using press oil or the like. Below.

When a press oil or wax is used as a lubricant during molding, it is necessary to remove the lubricating film containing metal powder remaining after molding with a solvent such as trichlorethylene. However, in recent years, in order to improve the global environment, the use of solvents typified by trichlorethylene has been greatly restricted, and the tendency to completely abolish is increasing, and the development of a lubricating film that is easy to remove with water after molding is required. There is.

Many inventions have been disclosed as methods of using waxes as lubricants. For example, JP-A-6
In the invention of JP-A 2-812221, montan wax, carnauba wax, polyethylene oxide wax, and microcrystalline wax are used as the main components of the lubricant, and a lubricant containing a surfactant, a metal soap, and a solid lubricant is used as the aluminum. It is disclosed that a cold plastic working is performed after coating and drying a metal material such as the above to form a lubricating film on the surface of the metal. In addition, JP-A-3-134094
In the invention of the publication, a synthetic ester wax having an acid value of 5 or less, a hydroxyl value of 10 or less, and a melting point of 50 ° C. or less is an ester of a hindered alcohol having a neo skeleton and a saturated fatty acid having 10 to 14 carbon atoms. A method is disclosed in which a lubricant mainly composed of aluminum is applied to a metal material such as aluminum and dried to form a lubricating film on the surface of the metal, and then cold plastic working is performed.

All of these methods use wax as a main component, and the lubricating performance depends substantially on the melting point of the wax as the main component, that is, the high-melting-point wax has excellent lubricating performance. Is known. Therefore, the lubricating performance and the lubricating film removing performance are contradictory, and it is difficult to satisfy both performances at the same time. Further, in these methods, the temperature of the mold in the actual continuous press work reaches 80 ° C. or more due to frictional heat between the tool and the processing material, heat generated by plastic deformation of the processing material, etc., so the wax softens and melts. The retention of excellent processing performance as a solid lubricating film is reduced, and the melted wax is scattered from the mold and the processing material, resulting in the disadvantage that the surroundings of the processing apparatus and the working environment are unavoidable.

On the other hand, as a measure for reducing the contamination around the processing equipment and the working environment due to the scattering of the lubricant contained in the oil-based and wax-based lubricants, the invention of Japanese Patent Application Laid-Open No. 50-37966 discloses a specific molecular weight. A method of using polyethylene glycol and polyvinyl alcohol as a lubricating film and polyethylene oxide as a lubricating additive is disclosed.
However, polyvinyl alcohol is hard and brittle as a film, and its water solubility is not sufficient. Therefore, in the invention of Japanese Patent Laid-Open No. 50-37966, polyethylene glycol is used in combination to achieve compatibility with the removability of the lubricating film. However, when polyethylene glycol is used, the removability of the lubricating film can be improved, but it hinders the formation of the lubricating film, so that the lubricating performance and the removability of the lubricating film cannot be satisfied at the same time.

[0008]

As described above, none of the prior art methods for forming a lubricating film can satisfy both the metal forming workability and the lubricating film removing property after the forming work. The present invention aims to solve these problems, has excellent forming processability on the surface of the metal, lubricity, and removability of the lubricating film after the forming process, that is, easy to remove by washing with water. The present invention is intended to provide a lubricant composition for forming a lubricating film and a method for forming a lubricating film that do not adversely affect the pretreatment process for coating and the coating process that are performed thereafter.

[0009]

[Means for Solving the Problems] The inventors of the present invention diligently studied a lubricant composition and a method for forming a lubricant film, which simultaneously satisfy excellent moldability, lubricity, and the ability to remove a lubricant film by water after molding. As a result, at least one selected from water-soluble polyesters and water-soluble polysaccharides and at least one selected from water-soluble polyamides as a resin component, and at least one selected from waxes having a melting point of 50 to 130. The present invention has been completed by finding that a lubricant composition consisting of one kind and water forms a lubricating film which is easily removed by washing with water on a metal surface.

That is, the present invention comprises (a) an average molecular weight of 3
At least one selected from water-soluble polyesters of 50,000 or more and less than 500,000 and water-soluble polysaccharides;
(B) at least one selected from water-soluble polyamides, (c) at least one selected from waxes having a melting point of 50 to 130 ° C., and (d) water,
And (a) / (b) = 50/1 to 1/50 by weight, and the content of (c) is 3 to 90 parts by weight per 100 parts by weight of (a) + (b). The present invention provides a lubricant composition for forming a lubricating film, which is easily washed and removed with water.

Further, according to the present invention, (a) an average molecular weight of 30,000 or more, 50 or more on the surface of steel, plated steel, steel having a chemical conversion film formed thereon or plated steel having a chemical conversion film formed thereon.
At least one selected from water-soluble polyesters and water-soluble polysaccharides of less than 20,000, (b) at least one selected from water-soluble polyamides, and (c) a melting point of 50.
At least 1 selected from waxes having a temperature of 130 ° C
Consisting of seeds and (d) water, and (a) / (b) =
The lubricant composition having a weight ratio of 50/1 to 1/50 and a content of (c) of 3 to 90 parts by weight per 100 parts by weight of (a) + (b) is applied and dried. , 0.
Also provided is a method for forming a lubricating film, which is characterized by forming a film of 1 to 5.0 g / m ^{2 and} is easily washed and removed with water.

The structure of the present invention will be described in detail below. The lubricant composition according to the present invention contains the component (a) and the component (b) as resin components, and a specific example of the water-soluble polyester which is one of the component (a) has an alkylene glycol structure. Examples thereof include esters of dihydroxy compounds and polycarboxylic acids. Examples of such water-soluble polyesters include a dihydroxy compound having an average molecular weight of 1,000 or more and less than 30,000, which is obtained by addition-polymerizing an alkylene oxide containing ethylene oxide to an organic compound having two active hydrogen groups, An average molecular weight of 30,000 or more obtained by reacting with a polycarboxylic acid or an anhydride thereof or a lower alkyl ester thereof,
High molecular weight compounds of less than 500,000 are mentioned.

When the average molecular weight of the water-soluble polyester is less than 30,000, the solubility in water is sufficient, but the hygroscopicity increases, and the lubricating film formed from the lubricant composition containing the same necessarily absorbs water. Undesirably increases. Further, if the average molecular weight is 500,000 or more, the dissolution rate in water decreases, and a lubricating film formed from a lubricant composition containing this cannot be easily removed by washing after molding, which is not preferable.

Examples of the organic compound having two active hydrogen groups constituting such water-soluble polyesters include ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, butylamine, polytetramethylene glycol and aniline. . Examples of the alkylene oxide containing ethylene oxide to be addition-polymerized with an organic compound having two active hydrogen groups include ethylene oxide alone or a mixture of ethylene oxide.

The dihydroxy compound obtained by subjecting these to block addition polymerization by a known method is required to have an average molecular weight of 1,000 or more. When the average molecular weight is less than 1,000, the addition ratio of the polyvalent carboxylic acid increases when forming the polyester, which is not preferable because the resulting polyester has insufficient solubility in water. In addition, when the average molecular weight is 30,000 or more, the ester content decreases, and it is difficult to form a film, which is not preferable.

Next, the polyvalent carboxylic acid or its anhydride or its lower alkyl ester to be reacted with the dihydroxy compound is, for example, oxalic acid, maleic acid, phthalic acid, isophthalic acid, terephthalic acid, sebacic acid, adipic acid. Or an anhydride thereof, or a dimethyl ester or diethyl ester thereof, or an anhydride of pyromellitic acid. The esterification reaction of these polyhydric carboxylic acids or their anhydrides or their lower alkyl esters with the above dihydroxy compounds is usually carried out in a closed vessel. The esterification reaction is not just a reaction of one molecule, but one carboxyl group of a polycarboxylic acid is esterified with an alcohol group of a dihydroxy compound, and the unreacted residual carboxyl group and another new dihydroxy group are formed. This is a reaction in which the compound is esterified, and then the unreacted alcohol group of the esterified hydroxy compound and the new polyvalent carboxylic acid are esterified to gradually increase the molecular weight. The ratio of reacting the dihydroxy compound with the polyvalent carboxylic acid or its anhydride or its lower alkyl ester may be any ratio as long as the resulting water-soluble polyester has an average molecular weight of 30,000 or more. It doesn't matter. On the other hand, in order to reduce the average molecular weight to less than 500,000, it is necessary to control the reaction conditions. For example, the pressure in the closed container used for the reaction is reduced to control.

The water-soluble polysaccharide, which is another component of (a), is specifically shown. One or a mixture of two or more selected from starch, pullulan, and those represented by the general formula (1). Is mentioned.

[0018]

[Chemical 1] In the above general formula (1), R is H, CH ₃ , [—CH ₂ —
CH ₂ -O] _n -H, _{[- CH 2 -CH (CH 3)} -O ] _n
At least one group selected from the group —H, provided that n is an integer of 1 or more.

As a concrete example of the water-soluble polyamides (b) which is another one of the resin components, those having a tertiary amine in the main chain, side chain or both main chain and side chain, or the main chain And those having a polyalkylene glycol structure. Examples of polyamides having a main chain, a side chain, or a tertiary amine in both the main chain and the side chain include polymers of diamines such as bisaminopropylpiperazine and aminoethylpiperazine and dicarboxylic acids such as adipic acid and sebacic acid. , A copolymer of them with lactams, a copolymer of α-diaminomethyl-ε-caprolactam or other lactams, and the like. Further, as having a polyalkylene glycol structure in the main chain, a polymer of a diamine or hexamethylenediamine obtained from polyethylene glycol having a molecular weight of about 200 to 4,000 and a dicarboxylic acid such as adipic acid or sebacic acid, or And at least one selected from copolymers of lactams.

When the weight ratio of the water-soluble polyesters as the resin component in the present invention, the water-soluble polysaccharide (a) and the water-soluble polyamides (b) is (a) / (b) = 1/50 or less, Since the strength of the lubricating film formed on the surface of the metal is insufficient, the lubricating performance is deteriorated, which is not preferable. Also, the weight ratio is 50
When it exceeds / 1, the lubricating performance of the lubricating coating formed on the surface of the metal is sufficiently exhibited, but the coating removability with water is insufficient, which is not preferable. In order to obtain better lubrication performance and film removal performance, the weight ratio of (a) / (b) should be 20 / 1-
It is preferably 1/20.

The water-soluble polyesters and the water-soluble polysaccharides can be used alone, respectively, but when both are used, the ratio is not particularly limited. However, in order to exhibit proper lubricity and removability of the lubricating coating with water, the weight ratio (a) / (b) of the water-soluble polyester (a) and the water-soluble polysaccharide (b) is 100 / 1 to 1/10
The range of 0, more preferably 20/1 to 1/20 is good. However, the resin component having such a structure alone is not sufficient to satisfy the desired lubricity. Generally known hydrocarbon-based, fatty acid amide-based, ester-based, alcohol-based, metal soap-based and inorganic-based additives are known as additives for improving lubricity, but the present inventors have conducted extensive studies. As a result, it is better to select and use substances that exist on the surface of the resin film rather than disperse the additives in the resin film formed, and reduce the friction between the surface of the molded product and the mold. It was found that this is a method of maximizing the lubricating effect.

Wax is preferable as a constituent component which imparts such characteristics to the film. Used in the present invention (c)
The wax having a melting point of 50 to 130 ° C. is preferable, and one or more kinds of these waxes are used. When the melting point of the wax is less than 50 ° C, and 13
When it exceeds 0 ° C, the lubricity is insufficient. As the type of wax, an aqueous emulsion of polyethylene wax is more preferably used. It is preferable to add 3 to 90 parts by weight of wax to 100 parts by weight of the resin component. If the wax content is less than 3 parts by weight with respect to 100 parts by weight of the resin component, the desired lubricating performance cannot be obtained.
If it exceeds the weight part, the lubricating performance is satisfied, but the film removability with an aqueous detergent is insufficient, which is not preferable.

The lubricant composition of the present invention is a water-based lubricant, and the amount of water in (d) used is the same as in the above (a) and (b).
It is the total remaining amount of the components (c) and (c) and is not particularly limited, but it also varies depending on the film formation amount.

Addition to the lubricant composition of the present invention
Additives that can be used are added to ordinary water-based resin paints.
Additives used, such as leveling agents, wetting agents, thickeners, etc., can also be added to the lubricant composition. Further, in order to improve weldability, one or more selected from zinc powder, powdered nickel, metal powder such as stainless powder, and inorganic compound-based conductive agent such as ITO can be added and used.

Next, a method for forming a lubricating film using the lubricant composition of the present invention, which can be easily washed and removed with water, will be described below. The above lubricant composition is applied to the metal surface and then dried to form a film of 0.1 to 5.0 g / m ² . If it is less than 0.1 g / m ² , lubricity is insufficient, and 5.0
If it exceeds g / m ² , the lubricating performance is satisfactory but the film removability is deteriorated, which is not preferable. When applying the lubricant composition to the surface of the metal, it is preferable to preliminarily clean the metal surface by alkali cleaning or other suitable cleaning means, which prevents cissing during application of the lubricant composition. It is effective to do. Further, a zinc phosphate-based coating, an iron phosphate-based coating, a chromate coating or the like is applied to the surface of the metal in advance, and then the lubricant composition is applied, and then dried to give a metal surface of 0.1 to 0.1%. 5.0 g / m ²
By forming the film of (1), it is possible to further improve the corrosion resistance and the coating adhesion after removing the lubricating film. Examples of the metal include steel and plated steel.

[0026]

EXAMPLES The effects of the present invention will be specifically described below with reference to Examples and Comparative Examples. 1. Preparation of test pieces (1) Test material Electrogalvanized steel sheet (EG) with a plate thickness of 1.0 mm, zinc-nickel alloy plated steel sheet (Zn-Ni), alloyed hot-dip galvanized steel sheet (GA), 5% aluminum- Galvanized steel sheet (G
F) and 55% aluminium-zinc plated steel sheet (GL) were used as the test materials after being treated in the following steps.

Step (2): Alkaline degreasing fine cleaner 342 (manufactured by Nippon Parkerizing Co., Ltd.) Concentration: 20 g / L Liquid temperature: 60 ° C. Spray: 20 seconds ↓: Rinse water with tap water: 20 seconds ↓: Roll squeeze ↓ : Draining and drying ↓: Applying various lubricants Bar coater No. Using # 3, 5 mL / m ² was applied. However, the coating amount was adjusted by the solid content in the lubricant. ↓: Drying It was dried at an ambient temperature of 260 ° C. for 10 seconds (reached plate temperature =
150 ° C)

2. Performance test (1) Workability (lubricity) Using a high-speed cylindrical deep-drawing tester, wrinkle holding pressure = 0.7T
On, deep drawing speed = 10 m / min, a cylindrical deep drawing test was carried out, and evaluation was made by the limiting drawing ratio. For example, blank diameter = 88 mmφ, punch diameter = 40 mmφ, and the limiting aperture ratio at this time is 2.20. <Evaluation Criteria> ◎: Limiting draw ratio = 2.30 or more ○: Limiting draw ratio = 2.20 or more △: Limiting draw ratio = 2.10 or more ×: Limit draw ratio = less than 2.10.

(2) Film removability test A test plate cut into a size of 70 × 150 (mm) was subjected to a film removal under the condition of tap water using a tap water at a temperature of 60 ° C. for 60 seconds. The amount of carbon remaining on the surface (mg / m ² ) was measured with a carbon deposition amount measuring device to evaluate the film removability (removal rate).

[0030]

[Equation 1]

The composition, coating amount, and performance test results are shown in Tables 1, 2, 3, 4, and 5.

The types of polymers used and the types of wax emulsion contents are described below. [Symbol: PE] As water-soluble polyester, polyethylene glycol (average molecular weight of 3,000 in an autoclave)
0) Addition polymerization of 2,000 parts by weight of ethylene oxide to 200 parts by weight of diethylene oxide gave a dihydroxy compound having an average molecular weight of 32,000. Further, 16 parts by weight of dimethyl isophthalate was added to carry out a demethanol reaction to give an average molecular weight of 25
Ten thousand high molecular weight polyesters were used. [Symbol: SC] Commercially available corn starch was used. [Symbol: HPC] Hydroxypropyl cellulose (trade name: HPC-SL) manufactured by Nippon Soda Co., Ltd. was used. [Code: MC] Methylcellulose (trade name: Tylose MH20) manufactured by Hoechst Japan Ltd. was used. [Symbol: PA70] Water-soluble polyamide, a diamine represented by the following chemical formula, obtained from polyethylene glycol having a molecular weight of 1,000

[0033]

[Chemical 2]

Adipic acid salt (hereinafter referred to as diamine 1000) (70 parts by weight) and ε-caprolactam (30 parts by weight)
(Parts by weight) was used. [Symbol: PA90] A copolymer of aminoethylpiperazine adipate (90 parts by weight) and ε-caprolactam (10 parts by weight) was used. [Code: PVA] Product name of Kureha Co., Ltd .: PVA10
5 (polyvinyl alcohol) was used. [Code: EAA] Trade name of Mitsubishi Petrochemical Co., Ltd .: Yucaron A510W (weight ratio of ethylene / acrylic acid is 80/2
0 copolymer) was neutralized with ammonia, and an emulsion obtained by emulsification in water at a concentration of 20% by weight was used. [Code: WAX1] Product name: Sanyo Chemical Industries, Ltd .: K
UE-8 (polyethylene wax emulsion, wax melting point = 105 ° C.) was used. [Symbol: WAX2] Trade name: JW-150 (ethylene / paraffin wax emulsion, melting point of wax = 104 ° C./52° C.) manufactured by Johnson Polymer Co., Ltd. was used. [Code: O] Commercially available press oil having a specific gravity of 0.972, a kinematic viscosity (40 ° C.) of 868 cSt, a pour point of −2.5 ° C. and an acid value of 0.84 was used.

Examples 1 to 40 of the present invention have good workability and film removability. Comparative Examples 3, 10, 1
Nos. 7, 24 and 31 are examples of the composition of the present invention, but the amount of the film is large, and the film removability is insufficient. Comparative Examples 4, 11,
Nos. 18, 25, and 32 are examples in which the composition ratio of the coating is different from that of the present invention, and both performances of workability and coating removability are not satisfied. Comparative Examples 5, 12, 19, 26, and 33 are examples in which the coating amount is small and the workability is poor. Comparative Examples 1, 2, 6, 8,
9, 13, 15, 16, 20, 22, 23, 27, 2
Nos. 9, 30, and 34 are based on the conventional technique and are insufficient in workability and film removability. Comparative Examples 7, 14, 21, 35
Shows an example in which a self-emulsifying acrylic emulsion and wax are used as a lubricating component. The workability is sufficient but the film removability is extremely poor.

[0036]

As described above, by applying the lubricant composition of the present invention, excellent moldability and lubricity are imparted, and the lubricating film after press molding is easily removed by washing with water. Thus, it is possible to provide a lubricating film that does not adversely affect the pre-painting treatment step and the painting step performed in the subsequent steps.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

[0040]

[Table 4]

[0041]

[Table 5]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C10M 107: 44 109: 00) C10N 30:00 Z 8217-4H 40:24 Z 8217-4H 50: 08

Claims (3)

[Claims] (A) Average molecular weight of 30,000 or more, 50
At least one selected from water-soluble polyesters and water-soluble polysaccharides of less than 10,000, (b) at least one selected from water-soluble polyamides, and (c) waxes having a melting point of 50 to 130 ° C. At least one selected from (d) water and (a) / (b) = 50/1 to 1/50 in weight ratio, and the content of (c) is (a) + (B) Total 1
3 to 90 parts by weight relative to 00 parts by weight, and a lubricant composition for forming a lubricating film, which is easily washed and removed with water. 2. The weight ratio of the water-soluble polyester (a) and the water-soluble polysaccharide (b) is (a) / (b) = 100/1 to 1 /
The composition of claim 1 which is 100. 3. A water-soluble polyester having an average molecular weight of 30,000 or more and less than 500,000, on the surface of steel, plated steel, steel having a chemical conversion film formed thereon, or plated steel having a chemical conversion film formed thereon. At least one selected from water-soluble polysaccharides, (b) at least one selected from water-soluble polyamides, (c) at least one selected from waxes having a melting point of 50 to 130 ° C., and ( d) water, and (a) / (b) = 50/1 to 1/50 in weight ratio, and the content of (c) is (a) + (b) total 1
3 to 90 parts by weight relative to 00 parts by weight of a lubricant composition is applied and then dried to form a film of 0.1 to 5.0 g / m ^{2 on} the surface. Lubrication film formation method.