JP2009040954A - Lubricant composition for warm working of magnesium and magnesium alloy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricant composition for warm working excellent in reduction of load in processing, scratch resistance, low smoking, burning resistance and excellent in degreasing power in rolling and press forming of magnesium and magnesium alloys in warm regions. <P>SOLUTION: The lubricant composition is obtained by adding antioxidant consisting of at least a kind of primary antioxidant and at least a kind of secondary antioxidant to a base oil consisting of a branched type ester composed of a polyhydric alcohol and a fatty acid by forming an ester bonding and (or) a polyether compound having a polyphenyl ether in the molecular structure. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention, when plastic processing magnesium and magnesium alloy, in the processing in the temperature range, lubrication performance to reduce the processing load, low smoke generation performance to reduce the smoke generation during processing, lubricant of high temperature The present invention relates to a lubricating oil that has excellent burn-proof performance that suppresses deterioration, and has excellent degreasing properties after plastic working.

  Magnesium and magnesium alloys are extremely poor in workability in a temperature region where there are few sliding surfaces at 180 ° C. or less, and therefore, processing such as rolling or press molding is usually performed in a warm region of 180 ° C. to 350 ° C.

  As such a lubricant for magnesium and magnesium alloy, for example, Patent Document 1 has been proposed. This lubricant is mainly composed of polyisobutylene and has a good stainability after rolling, but has a good fuming property. There is a problem, and high-strength press molding generates wrinkles that are insufficiently lubricated.

  In addition, Patent Document 2 proposes to improve low smoke generation and kogation resistance by using a heat-resistant ester as a base, but it completely satisfies the required performance of low smoke generation and kogation resistance. In addition, the lubricating performance was insufficient, and it was insufficient as a lubricant for magnesium and magnesium alloy to be warm processed.

  Furthermore, the silicone oil excellent in heat resistance proposed in Patent Document 3 has low smoke generation and good kogation resistance. However, silicone oil has a high coefficient of friction and is particularly poor in degreasing, so it has a problem in the subsequent process. Has occurred.

In addition, although the lubricating oil added with fluorine-based oil has a high coefficient of friction, it can satisfy the above-mentioned required performance from silicone oil including degreasing properties, but there are problems in terms of cost and environment. Therefore, magnesium and magnesium alloys are warm with low fuming and scoring resistance equivalent to silicone oil base and fluorinated oil lubricants, and with excellent lubrication performance to reduce processing load and degreasing after plastic processing. Processing lubricants are now highly eagerly aspired.
JP 2006-131726 A JP 2004-323563 A JP 2003-253281 A

  The object of the present invention is the lubrication for warm working, which is excellent in all of the reduction of processing load, prevention of wrinkles, low smoke generation, scorch resistance, and degreasing in the rolling and pressing of magnesium and magnesium alloys in the warm region. It is to provide an agent composition.

  As a result of intensive studies in order to solve the above problems, the present inventors have found that at least one polyether compound having (A) a branched ester and / or (B) a polyphenyl ether in its molecular structure. Contained in the base oil with excellent heat resistance, combined with (C) a primary antioxidant that blocks radical chain polymerization as an antioxidant and a secondary antioxidant that decomposes peroxides produced during oxidation It has been found that the squeezed lubricant composition achieves the intended purpose. Further, at this time, (D) an extreme pressure agent or the like was added to find a lubricant composition further improving the lubricity, and the present invention was completed.

  Further, the lubricant for warm working of magnesium and magnesium alloy of the present invention, when the lubricant composition is 100 parts by weight, the above base oil, the primary antioxidant and the oxidation process to prevent radical chain polymerization The secondary antioxidant that decomposes the peroxide generated in step (b) is used in combination with at least one or more of 0.2 to 10 parts by weight. Furthermore, the lubricity can be improved by containing 2.0 to 29.8 parts by weight of the extreme pressure agent.

  Conventionally, there has been no lubricating oil that satisfies all the required performances regarding processing load reduction, prevention of wrinkles, low smoke generation, scoring resistance, and degreasing properties. However, by using the lubricant of the present invention, any problem can be solved, and it is possible to process even shapes that have been difficult to mold due to the difficulty of workability unique to magnesium and magnesium alloys. The effect of becoming can be expected.

  The present invention will be specifically described below.

  In the present invention, at least one of (A) a branched ester and (B) a polyether compound is used as a base oil.

    Specifically, (A) is a branched type in which a linear or branched saturated fatty acid having 6 to 18 carbon atoms is ester-bonded to two or more hydroxyl groups of a polyhydric alcohol having a branched carbon chain. It is an ester, and one or more of these are used.

    As the polyhydric alcohol, those having 2 to 4 grades can be used, and examples thereof include neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol and the like. From the viewpoint of heat resistance, esters in which the hydrogen atom is not contained in the β-position carbon of the alcohol molecule are preferable. Typical examples of fatty acids include linear or branched caproic acid, caprylic acid, lauric acid, myristic acid, stearic acid, and the like.

  (B) is a polyether compound having a polyphenyl ether in the molecular structure, which has polyphenyl ether as a main chain, and includes at least one alkyl chain in the polyphenyl ether alone or in the terminal phenyl group, Examples include pentaphenyl ether, tetraphenyl ether, alkyl diphenyl ether, and the like.

The base oil contains 60.0 to 99.8 parts by weight, based on 100 parts by weight of the lubricant composition.
(C) The antioxidant contains a primary antioxidant and a secondary antioxidant in combination of at least one of each.

  Primary antioxidants are phenolic or amine antioxidants that block radical chain polymerization of alkyl groups that occur during base oil oxidation. Radicals generated from the base oil alkyl groups by heat or light energy (R・) Is captured to prevent chain polymerization. The action is considered as follows.

RH + (heat and light energy) ⇒ R ・ + H ・
R ・ + O ₂ ⇒ ROO ・
Primary antioxidant ＋ R ・ ⇒ RH ＋ Primary antioxidant ・
ROO ・ ＋ Primary antioxidant ・ ⇒ Primary antioxidant-OOR
Primary antioxidant -OOR ⇒ Primary antioxidant + ROOH

Typical examples of phenolic compounds include BHT (2,6-di-t-butyl-p-cresol), butylhydroxyanisole, and 2,2-methylenebis (4-methyl-6-t-butylphenol). Examples of amines include phenyl-β-naphthylamine, α-naphthylamine, N, N-diphenyl-p-phenylenediamine, and the like.

  As the secondary antioxidant, sulfur-based and phosphorus-based antioxidants are used and have an action of decomposing peroxide generated in the process of base oil oxidation.

  That is, as described above, peroxide (ROOH) generated when heat or light energy is oxidized in the presence of oxygen is decomposed as follows to capture active oxygen.

ROOH + 2R'SH ⇒ ROH + R'SOR '(Sulfur system)

Typical examples include sulfur-based dilauryl thiodipropionate, distearyl thiopropionate, and 2-mercaptobenzimidazole, and phosphorus-based tridecyl phosphite, triphenyl phosphite, and trilauryl. And trithiophosphite.

  Antioxidants alone are effective in smoke and burn resistance, but use of at least one or more primary and secondary antioxidants further improves smoke and burn resistance. .

  As for the addition amount of the antioxidant, when the lubricant composition is 100 parts by weight, the base oil contains 0.2 to 10 parts by weight of the primary antioxidant and the secondary antioxidant.

  The preferable addition amount is 1.5 to 6.0 parts by weight, and the preferable ratio (weight) of the primary antioxidant and the secondary antioxidant is 1: 5 to 5: 1. If the addition amount is 1.5 parts by weight or less, the effect is small, and if it is 6.0 parts by weight or more, the cost is high. Moreover, it is because a synergistic effect will become small if the ratio (weight) of both is 1: 5 or less mutually.

  (D) Examples of extreme pressure agents include alkylphosphonic acids based on phosphorus, sulfurized fats and oils, sulfurized olefins, sulfurized lard, polysulfide and the like based on sulfur, which have the effect of improving lubricity.

  The extreme pressure agent is preferably contained in an amount of 2.0 to 29.8 parts by weight based on 100 parts by weight of the lubricant composition.

  Further, solid lubricants such as polytetrafluoroethylene (PTFE), calcium carbonate, silica, mica, etc. may be added, and other known additives may be added as long as the object of the invention is not impaired. May be.

  As the magnesium alloy which is a subject of the present invention, those conventionally known are widely included, but representative examples include AZ-31 and AZ-61.

In order to facilitate understanding of the present invention, examples and comparative examples are shown below.
Examples 1 to 8 and Comparative Examples 1 to 10 were prepared by blending predetermined amounts of the components shown in Tables 1 and 2.

(Test method for burning resistance and smoke generation)
1. Test material
A-5052
(A 1mm deep recess is made in the flat plate center using an Erichsen tester)
Test temperature: 250 ° C, 280 ° C
Test time: 20min
2. Test method
About 50 mg of a predetermined component is dropped into a depression of the test material, and the sample is allowed to stand for a predetermined time in an electric furnace set to a predetermined temperature.
3. Evaluation
The sample after the test is marked with “◎” when there is no burn or discoloration, “○” when there is discoloration but no burn, and “×” when there is burn.

            In addition, the smoke generation state is visually observed as a smoke generation state. When there is almost no smoke, “○” is indicated when smoke is present, and “X” is indicated.

(Bowden test method)
1. Test material: AZ-31, steel ball (SUS304)
Test temperature: 280 ° C
Test load: 1kg
Speed: 3.88mm / s
Number of sliding times: 10 reciprocations (70mm / rot)
2. Test method: A few drops of the sample are dropped on the test material, a load [N] of 1.0 kg is applied, the steel ball is moved at a sliding speed of 3.88 [mm / s], and the friction force [F] is measured. Then, the coefficient of friction is obtained from the following equation.

μ = [F] / [N]
3. Evaluation: The friction coefficient is obtained from the calculation formula described above, and the lubricating performance of the test oil is confirmed. The evaluation method is indicated by 係数 for a friction coefficient of 0.2 or less, ○ for a friction coefficient greater than 0.2 and 0.35 or less, and × for a friction coefficient greater than 0.35.

(Degreasing test method)
1. Test material: AZ-31
Adhesive oil amount: 1 g / m ² (Apply each oil in advance)
Alkaline cleaning solution: sodium orthosilicate 3% + nonylphenol EO adduct (Nonipol 100 = Sanyo Kasei) 0.3%
Cleaning liquid temperature: 80 ° C
2. Test method: After immersing in an alkaline cleaning solution for 5 minutes, the test material is rinsed (rinse) several tens of times, and then the wettability of the test material surface is evaluated (visually).

        3. Judgment method: Degreasing property was judged as ◎ when the wetted area was 90% or more, ◯ when 70 to 90%, Δ when 40 to 70%, and x when 40% or less.

  Each component shown in Table 1 was blended to prepare a composition.

  Each component shown in Table 1 was blended to prepare a composition.

  Each component shown in Table 1 was blended to prepare a composition.

  Each component shown in Table 1 was blended to prepare a composition.

  Each component shown in Table 1 was blended to prepare a composition.

  Each component shown in Table 1 was blended to prepare a composition.

  Each component shown in Table 1 was blended to prepare a composition.

Each component shown in Table 1 was blended to prepare a composition.

Comparative Examples 1-10

A composition was prepared by blending the components shown in Table 2.

(*) Comparative Examples 1 to 5 and 7 to 8 have poor scorch resistance evaluation, and excluded the evaluation of the Bowden test.
The components used in Tables 1 and 2 are as follows.
・ Branched ester a: Pentaerythritol fatty acid ester (H-4810BR-32 = manufactured by NOF Corporation)
・ Branched ester b: Pentaerythritol fatty acid diester (HR-200 = manufactured by NOF Corporation)
・ Branched ester c: Branched ester A: B = 3: 7 mixed product ・ Polyether: Tetraphenyl ether (S-3103 = Matsumura Oil Research Institute)
Antioxidant H: 4,4′thiobis (6-tertiarybutyl-3-methylphenol) (Sumilyzer WX-R = manufactured by Sumitomo Chemical)
・ Antioxidant J: Bisphenol compound (Sumilyzer GA80 = manufactured by Sumitomo Chemical)
Antioxidant K: Sulfur-based antioxidant (3-laurylthiopropionate) = 6: 1 (manufactured by Sumitomo Chemical)
・ Extreme pressure agent P: Phosphorus extreme pressure agent (alkyl phosphonic acid diisopropyl ester = Daido Chemical)
・ Extreme pressure agent S: Sulfurized oil (Dairubu GS-110 = Dainippon Ink)
Solid lubricant Q: Polytetrafluoroethylene (KTL-8N = Kitamura)
・ Low viscosity mineral oil: Paraffinic mineral oil (NT200: manufactured by Fuji Kosan)
・ High viscosity mineral oil: Paraffinic mineral oil (NT700: manufactured by Fuji Kosan)
・ Oleic acid: (OA-P: manufactured by Irono Oil Industries)
Palm oil :: (PM-A-10: Fuji Oil)
Unsaturated branched ester: pentaerythritol tetraoleate (Unistar H-481R: manufactured by NOF Corporation)
・ Silicone oil: Dimethyl silicone oil (Silicon KF-96: manufactured by Shin-Etsu Chemical)
・ Fluorine oil: (DEGNUM S-200: Daikin Industries)

The following can be seen from Tables 1 and 2.

(1) As for the result of Examples 1-8, it has confirmed that the scorch resistance was favorable compared with Comparative Examples 1-8 in any case. In particular, Examples 2, 3 and 7 had excellent results at 280 ° C., and were not inferior even when compared with the silicone oil of Comparative Example 9 and the fluorine oil of Comparative Example 10.

  (2) The fuming property was the same, and all of Examples 1 to 8 had little fuming property, and Comparative Examples 1 to 8 had large fuming property.

  (3) Since Examples 1 to 4 have good kogation resistance, the friction coefficient in the Bowden test was also relatively low and good. A low friction coefficient leads to a reduction in processing load and prevention of wrinkles. The same applies to the solid lubricant added in Example 7.

  (4) The addition of the extreme pressure agents of Examples 5, 6 and 8 has a low coefficient of friction and improved lubricity.

(5) Although Comparative Examples 9 and 10 had good kogation resistance and smoke generation, the degreasing property was extremely poor compared to Examples 1 to 8, the friction coefficient in the Bowden test was high, and the lubricity was poor. .

Claims (6)

    (C) Antioxidation to a base oil comprising at least one of a branched ester in which a polyhydric alcohol and a fatty acid are ester-bonded and / or (B) a polyether compound having a polyphenyl ether in the molecular structure. A lubricant composition for warm working of magnesium and a magnesium alloy, comprising at least one primary antioxidant and a secondary antioxidant in combination as an agent.     The warm processing of magnesium and magnesium alloy according to claim 1, wherein the base oil contains 0.2 to 10 parts by weight of a primary antioxidant and a secondary antioxidant when the lubricant composition is 100 parts by weight. Lubricant composition.     3. The magnesium and magnesium alloy according to claim 1, wherein the primary antioxidant is a phenol-based or amine-based antioxidant having an effect of blocking radical chain polymerization that occurs during the oxidation process, and contains at least one kind. A lubricant composition for warm processing.     The secondary antioxidant is a sulfur-based or phosphorus-based antioxidant having an action of decomposing a peroxide generated in the oxidation process, and contains at least one kind. A lubricant composition for warm working of magnesium and magnesium alloys.     Furthermore, (D) Lubricant composition for warm processing of magnesium and magnesium alloy in any one of Claims 1-4 which contains 2.0-29.8 weight part of extreme pressure additives. 6. The lubricant composition for warm working of magnesium and magnesium alloy according to claim 5, wherein the extreme pressure additive is at least one selected from phosphorus-based and sulfur-based extreme pressure additives.