JP5588318B2 - Oil-based plunger lubricant composition - Google Patents

Description

  The present invention relates to an oil-based plunger lubricant composition supplied between a plunger tip and an injection sleeve of a die casting machine when a metal or alloy melt is subjected to die casting.

Conventionally, a molded product made of a metal or an alloy, that is, a cast product, is manufactured while supplying a melt (molten metal) to, for example, a cavity of a die casting machine to give a predetermined shape. In this manufacturing method, usually, a lubricant (lubricant composition) is supplied between the plunger tip and the injection sleeve to reduce friction between them.
Examples of the lubricant composition include an aqueous graphite-containing composition (for example, Patent Document 1), an O / W type or W / O type graphite-free emulsion composition (for example, Patent Document 2), mineral oil, fats and oils, and the like. An oil agent composition containing a synthetic oil and an oil agent composition in which graphite is further dispersed are widely used.

JP 2008-264847 A JP 2000-15419 A

When a lubricant composition containing graphite is used, the working environment and the cast product obtained may be easily contaminated. Further, the O / W-type or W / O-type graphite-free emulsion composition only delays the time until the lubricant is ignited by the heat of vaporization of water contained therein, and remains in the high-temperature injection sleeve. It does not suppress even the flammability of the component, but merely by adding water, the oil concentration is relatively lowered to show a flame suppression effect. In addition, emulsion compositions generally have poor lubricity compared to non-hydrous lubricants, and in order to prevent sudden wear of plunger tips and injection sleeves, the supply amount must be increased, resulting in an increase in excess oil content. The actual situation is that a sufficient anti-inflammatory effect is not obtained.
Further, in the case of the above oil agent composition, there is a case where the molten metal is ignited when the molten metal is supplied to the cavity. When the supplied lubricant is consumed for ignition, sufficient lubricant is not interposed on the sliding surface, leading to a decrease in productivity of the cast product.

  An object of the present invention is to provide an oil-based plunger lubricant composition that is non-hydrated and non-graphite-type, and suppresses ignition during supply of molten metal and deterioration of the working environment.

By using a composition containing mineral oil, calcium sulfonate , wax , silicone, and an aromatic phosphate , the present inventors have solved the above problems and completed the present invention.

The present invention is as follows.
1. An oil-based plunger lubricant composition comprising mineral oil, calcium sulfonate , wax , silicone, and aromatic phosphate ester .
2 . 2. The oil type plunger lubricant composition according to 1 above, which contains a wax having a melt viscosity at 140 ° C. of 300 to 11,000 mPa · s.

According to the oil-based plunger lubricant composition of the present invention, in particular, due to the inclusion of calcium sulfonate , wax , silicone and aromatic phosphate ester , the adsorptivity to the sliding surface is high, Oil film breakage is suppressed, excellent lubrication performance is provided, and ignition and deterioration of the working environment when supplying molten metal to the cavity can be suppressed. Therefore, the oil-based plunger lubricant composition of the present invention is suitable for use in a die casting machine for producing a large casting product, and a good working environment can be obtained.

It is a schematic plan view which shows the flammability evaluation apparatus in [Example]. It is a schematic sectional drawing which shows the flammability evaluation apparatus in [Example]. It is a schematic sectional drawing which shows that the molten metal was supplied to the cavity in a test device. It is a schematic sectional drawing which shows that casting was discharged | emitted from the test apparatus. It is the schematic which shows the evaluation apparatus (adhesion slip test machine) of the lubricity in [Example]. It is a graph which shows the friction coefficient measured in [Example].

The oil-based plunger lubricant composition of the present invention contains mineral oil, calcium sulfonate , wax , silicone and aromatic phosphate ester . The composition of the present invention may further contain at least one component selected from fats and oils, synthetic oils, and inorganic powders.

  As the mineral oil, a general mineral oil can be used as a base oil in the field of lubricating oil. Specific examples include paraffinic mineral oil and naphthenic mineral oil. These mineral oils may be treated by distillation under reduced pressure, degreasing, solvent extraction, hydrocracking, solvent dewaxing, sulfuric acid washing, clay refining, hydrorefining and the like.

The kinematic viscosity of the mineral oil (100 ° C.), from the viewpoint of lubricating performance, preferably 15 to 35 mm ² / s, particularly preferably 25 to 35 mm ² / s.

  Examples of the calcium sulfonate include a calcium salt of petroleum sulfonic acid, a calcium salt of substituted or unsubstituted aromatic sulfonic acid, an overbased calcium salt of petroleum sulfonic acid, and an overbased of substituted or unsubstituted aromatic sulfonic acid. Calcium salt and the like. These compounds may be used alone or in combination of two or more. In the present invention, while maintaining good lubrication performance, it is possible to obtain an effect of suppressing flammability when supplying molten metal, overbased calcium salt of petroleum sulfonic acid and overbased calcium of alkyl-substituted aromatic sulfonic acid Salts are preferred.

  The content of the calcium sulfonate is 100 masses of the mineral oil because the viscosity of the composition does not increase excessively and the effect of suppressing the ignition of molten metal is obtained while maintaining good lubrication performance. When it is made into a part, Preferably it is 10-30 mass parts, Most preferably, it is 15-25 mass parts. If the content of the calcium sulfonate is too small, the lubrication performance may be lowered.

Examples of the wax include petroleum wax, oxidized wax, natural wax and the like. These may be used alone or in combination of two or more.
Examples of petroleum waxes include paraffin wax, olefin wax, polyethylene wax, and polypropylene wax.
Examples of the oxidized wax include oxidized polyethylene wax and oxidized polypropylene.
Examples of natural waxes include beeswax, carnauba wax, and montan wax.

The melt viscosity (140 ° C.) of the wax is preferably 300 mPa · s or more, more preferably 300 to 11,000 mPa · s, and still more preferably 350 to 10 because oil film strength on the sliding surface is sufficiently maintained. 000 mPa · s, particularly preferably 400 to 9,000 mPa · s.
In the present invention, a plurality of waxes having different melt viscosities can be used in combination. Examples thereof include (1) at least one wax having a melt viscosity in the range of 3,000 to 11,000 mPa · s, and at least 1 having a melt viscosity in the range of 300 mPa · s to less than 3,000 mPa · s. A mode in which the waxes are combined, (2) at least one wax having a melt viscosity in the range of 3,000 to 6,500 mPa · s, and a melt viscosity of more than 6,500 mPa · s to 11,000 mPa · s. Examples include a combination with at least one wax in the range of s or less.
In the case of the above aspect (1), for example, a wax (W1a) having a melt viscosity of 3,500 to 6,000 mPa · s and a wax (W1b) having a melt viscosity of 300 to 2,500 mPa · s may be used in combination. it can. The mass proportions of the waxes (W1a) and (W1b) are preferably 30 to 70 mass% and 70 to 30 mass%, more preferably 40 to 60 mass%, respectively, when the total of these is 100 mass%. It is 60-40 mass%.
In the case of the above aspect (2), for example, a wax (W2a) having a melt viscosity of 3,500 to 6,500 mPa · s and a wax (W2b) having a melt viscosity of 7,000 to 10,000 mPa · s are used. It can be used in combination, has high adsorptivity to the sliding surface, suppresses oil film breakage, and provides excellent lubrication performance. The mass proportions of the waxes (W2a) and (W2b) are preferably 30 to 70 mass% and 70 to 30 mass%, more preferably 40 to 60 mass%, respectively, when the total of these is 100 mass%. It is 60-40 mass%.

  Since the oil film strength on the sliding surface is sufficiently maintained, the content of the wax is preferably 1 to 10 parts by mass, particularly preferably 2 to 6 parts by mass when the mineral oil is 100 parts by mass. is there. If the wax content is too low, sufficient oil film strength on the sliding surface may not be obtained. On the other hand, when there is too much content of the said wax, the viscosity of a composition may rise too much. Moreover, there may be a paste-like stain around the equipment.

  In the oil-based plunger lubricant composition of the present invention, the wax may be contained by being compatible with other components, or may be dispersed as fine particles.

The oil-based plunger lubricant composition of the present invention contains silicone and aromatic phosphate ester , and can further contain at least one component selected from fats and oils, synthetic oils and inorganic powders, and is more excellent. In addition, it is possible to obtain the lubrication performance and the suppression effect of the ignition when supplying the molten metal.

As the silicone, conventionally known compounds can be used as silicone oil or silicone wax. Specific examples include straight silicone and modified silicone. These may be used alone or in combination of two or more.
Examples of the straight silicone include dimethyl silicone, cyclic silicone, methylphenyl silicone, and methylhydrogen silicone.
The modified silicone may be partially or wholly modified by an alkyl group, an aralkyl group, an amino group, a carboxylalkyl group or a carboxylic acid alkyl group, a hydroxyalkyl group, an aminoalkyl group, a polyether group, a carbinol group, or the like. And organopolysiloxane.
In the present invention, a modified silicone is preferred, and an alkyl-modified silicone is particularly preferred because excellent lubricating performance and wettability are obtained and the oil film strength is improved.

In the oil-based plunger lubricant composition of the present invention , the silicone content is preferable when the mineral oil is 100 parts by mass because excellent lubricating performance and wettability are obtained and the oil film strength is improved. Is 1 to 10 parts by mass, particularly preferably 2 to 6 parts by mass.

As said aromatic phosphate ester, aromatic phosphate ester or its condensate etc. are mentioned. These compounds may be used alone or in combination of two or more.
The aromatic phosphate ester is preferably a compound having an aryl group having 6 to 30 carbon atoms, such as triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate. , Xylenyl diphenyl phosphate, diphenyl (2-ethylhexyl) phosphate, di (isopropylphenyl) phenyl phosphate, and the like.
Examples of the aromatic phosphate ester condensate include 1,3-phenylene bis (diphenyl phosphate), 1,3-phenylene bis (dixylenyl phosphate), and bisphenol A bis (diphenyl phosphate). Can be mentioned.
In the present invention, an aromatic phosphate ester and a condensate thereof are used because the effect of suppressing the ignition of molten metal is obtained.

In the oil-based plunger lubricant composition of the present invention, the content of the aromatic phosphate ester is preferably obtained when the mineral oil is 100 parts by mass because the effect of suppressing the ignition of molten metal is obtained. 5 to 15 parts by mass, particularly preferably 5 to 10 parts by mass. When there is too much content of the said aromatic phosphate ester, the smoke generation at the time of molten metal supply may become remarkable.

  By blending oil or synthetic oil with the oil-based plunger lubricant composition of the present invention, the viscosity of the composition can be adjusted while maintaining excellent lubricating performance.

  Examples of the fat include beef tallow, lard, rapeseed oil, coconut oil, palm oil, bran oil, and hydrogenated products thereof. These may be used alone or in combination of two or more.

  When the oil-based plunger lubricant composition of the present invention contains oils and fats, the content is preferably 2 to 25 parts by mass when the mineral oil is 100 parts by mass from the viewpoint of the above blending effect. Especially preferably, it is 5-20 mass parts.

  Examples of the synthetic oil include fatty acids obtained from the above fats and oils; esters of fatty acids and alcohols; poly α-olefins such as polybutenes; polyols such as polyethylene glycols and polyester polyols; other polyethers; polyesters; It is done. These may be used alone or in combination of two or more.

  When the oil-based plunger lubricant composition of the present invention contains a synthetic oil, the content is preferably 2 to 25 masses when the mineral oil is 100 mass parts from the viewpoint of the above blending effect. Parts, particularly preferably 5 to 20 parts by mass.

  Examples of the inorganic powder include graphite, graphite fluoride, molybdenum disulfide, tungsten disulfide, manganese sulfide, calcium fluoride, boron nitride, silicon nitride, mica, talc, and kaolin. These compounds may be used alone or in combination of two or more.

  When the oil-based plunger lubricant composition of the present invention contains an inorganic powder, the content of the mineral oil is 100 from the viewpoint of maintaining a balance between the lubricating performance and heat retention and the viscosity of the composition. When it is made into a mass part, Preferably it is 5-20 mass parts, Most preferably, it is 5-15 mass parts.

  The oil-based plunger lubricant composition of the present invention may contain additives such as an antioxidant, a metal deactivator, a rust inhibitor, and an antifoaming agent as necessary.

The oil type plunger lubricant composition of the present invention can be produced by mixing each component and then heating at a temperature of 120 ° C. to 160 ° C., for example.
In the oil-based plunger lubricant composition of the present invention, the lipophilic component is usually in a uniformly mixed state, but the wax may be dispersed in the form of fine particles depending on the type. Inorganic powder is also dispersed in the composition.

  The oil-based plunger lubricant composition of the present invention has a tendency to thicken as the temperature rises when heated to 100 ° C. or higher. Also excellent. Moreover, since the residence in an injection sleeve is suppressed, the ignition at the time of molten metal supply can be suppressed.

When the viscosity of the oil-based plunger lubricant composition of the present invention is measured using a B-type viscometer, it is preferably 600 to 1,800 mPa · s, more preferably 700 to 1,600 mPa · s at 100 ° C. s. Moreover, at 150 degreeC, Preferably it is 800-2,800 mPa * s, More preferably, it is 1,100-2,700 mPa * s, Most preferably, it is 1,200-1,900 mPa * s.
Since the oil-based plunger lubricant composition of the present invention has a viscosity corresponding to the above temperature, when it is supplied between the plunger tip of the die casting machine and the injection sleeve, the adsorptivity to the sliding surface is high. Oil film breakage is suppressed, a liquid pool made of a lubricant is less likely to be generated, accumulation over time is difficult to occur, and ignition during molten metal supply is also suppressed. Furthermore, after the cast product is discharged, the lubricant spread on the inner wall of the injection sleeve reattaches when the plunger tip is retracted, so that excessive deficiency is unlikely to occur and is discharged outside the system when the plunger tip retracts. Deposits can be reduced. These effects can be obtained even under high-speed injection conditions such as 2 to 3 m / sec.

  Examples of the material constituting the molten metal according to the present invention include aluminum, an aluminum alloy, a magnesium alloy, zinc, and a zinc alloy.

Examples of the method for using the oil-based plunger lubricant composition of the present invention include a method of dripping onto a plunger tip, or a method of performing spray coating or the like in an injection sleeve. In the latter case, the film is then spread on the plunger tip or a film made of a lubricant is formed on the inner surface of the injection sleeve.
The die casting machine to which the oil type plunger lubricant composition of the present invention can be applied is not particularly limited, and is suitable for use with a large die casting machine having a clamping force of 1,000 tons or more, for example.

1. Raw materials for oil-based plunger lubricant composition The raw materials used for the preparation of the oil-based plunger lubricant composition are shown below.
(1) Mineral oil Paraffinic base oil "Super Oil N320" (manufactured by JX Nippon Oil & Energy Corporation)
(2) Calcium sulfonate Overbased salt calcium sulfonate “LUBRIZOL5283C” (manufactured by Nippon Lubrizol)
(3) Wax (w1)
Polyethylene oxide “AC 316” having a melt viscosity of 8,500 mPa · s at 140 ° C. (manufactured by Honeywell)
(4) Wax (w2)
Polyethylene oxide “A-C 392” having a melt viscosity of 4,500 mPa · s at 140 ° C. (manufactured by Honeywell)
(5) Wax (w3)
Low molecular weight olefin wax “E-10” having a melt viscosity of 400 mPa · s at 140 ° C. (manufactured by Westlake Longview Corporation)
(6) Silicone Alkyl-modified silicone oil “TSF4421” (made by Momentive Performance Materials Japan)
(7) Phosphate ester tricresyl phosphate “TCP” (manufactured by Daihachi Chemical Industry Co., Ltd.)

2. Preparation and Evaluation of Oil Type Plunger Lubricant Composition After mixing the above raw materials at a mass ratio shown in Table 1 using a stirrer, the mixture was heated to 150 ° C. using an oil bath, whereby composition I II, III and IV were obtained. About the obtained composition, the viscosity in 0 degreeC, 10 degreeC, 25 degreeC, 50 degreeC, 100 degreeC, 150 degreeC, and 200 degreeC was measured with the B-type viscosity meter (refer Table 1).
For comparison, oil-based graphite “Plunger Height TG-Y” (manufactured by Nippon Graphite Co., Ltd.) and W / O emulsion “Neocaster RE-76” (manufactured by MORESCO) were used.

表３における判定基準は、以下の通りである。
Ａ：不燃・発煙なし
Ｂ：不燃・発煙のみ
Ｃ：炎小、鎮火速
Ｄ：炎小、鎮火遅
Ｅ：炎大、鎮火速
Ｆ：連続燃焼 Hereinafter, the above-described composition and commercially available products are referred to as “lubricants”, and evaluation items, methods, and results are shown.
(1) Evaluation of flammability Evaluation of flammability is performed by integrating a cavity (inner diameter: 75 mm) formed in a cylindrical shape inside the box-shaped main body 11 and an injection sleeve (box-shaped main body 11) forming the cavity. ), A molten metal inlet 15 (opening size: 80 mm × 50 mm) opened above the injection sleeve (upper side in FIG. 2), and a slidable cylindrical shape inserted from one side of the apparatus (right side in FIG. 1) The plunger tip 13 (diameter 74.4 to 74.7 mm) and the apparatus 1 provided with an openable and closable casting discharge portion 17 disposed on the other side of the apparatus (left side in FIG. 1) were used. (See FIGS. 1 and 2).
When the plunger tip 13 is in the position shown in FIG. 2, that is, when the molten metal inlet 15 is viewed from above, the exposed area on the tip side (cavity side) of the plunger tip 13 is the opening area of the molten metal inlet 15. It arrange | positioned so that it might be half (40 mm x 50 mm). Next, 3 ml of lubricant was spot-supplied to the central portion of the exposed outer peripheral surface of the plunger tip 13 (arrow in FIG. 2). Ten seconds later, about 300 milliliters of molten metal 2 (650 ° C.) made of ADC 12 was supplied to the cavity of the apparatus adjusted to 60 ° C. (see FIG. 3), and a rod-shaped casting 3 having a semicircular cross-sectional shape was obtained. It formed and discharged | emitted from the casting discharge part 17 (refer FIG. 4). Thereafter, this operation was continuously performed 10 times at intervals of about 3 minutes, and the flammability due to the lubricant was visually observed when the casting was discharged each time. The results are shown in Table 3.

The criteria in Table 3 are as follows.
A: No incombustibility / no smoke B: Only incombustibility / fumes C: Small flame, quenching speed D: Small flame, slow quenching E: Large flame, quenching speed F: Continuous combustion

In the case of oily graphite, the lubricant accumulates in the injection sleeve over time, and once ignited, the ignition at the time of supplying the molten metal does not stop. In the case of the W / O emulsion, the lubricant oozes out between the plunger tip and the injection sleeve, and a part thereof tends to flow to the tip of the plunger tip. The liquid that has flowed out to the front surface of the plunger tip is no longer involved in the friction surface and is lost only for combustion, which naturally leads to a decrease in primary performance. The reason for this is that the evaporation of water at the time of spreading increases the surface area and the surface tension is higher than that of oil, making it difficult for the plunger tip and the injection sleeve to enter the clearance, and the liquid staying at the dripping position rubs. It is thought to be due to flowing out without entering the plane.
On the other hand, in the case of the compositions (I) to (IV), it was confirmed that the ignition at the time of supplying the molten metal can be suppressed as compared with the oily graphite and the W / O emulsion.

(2) Lubricity evaluation Using the adhesion slip tester shown in FIG. 5, a sliding test was conducted in the following manner to measure the friction coefficient of the lubricant. In addition, about the W / O emulsion, it tested with the active ingredient after removing a water | moisture content.
(A) The surface of a test piece (160 mm × 30 mm × 2 mm) made of SKD61 of alloy tool steel was adjusted with # 1000 abrasive paper and then kept at 230 ° C. on a heater.
(B) About 1.0 mg of lubricant is applied to the contact portion of a steel ball (φ3 / 16 inch) and a test piece made of high carbon chrome, and a load (0.5 kg or 4.0 kg) is applied to the steel ball. However, the surface of the test piece was continuously slid 10 times at a speed of 4 mm / second over a length of 4 mm, and the coefficient of friction was measured each time.
(C) This test was repeated three times, and the coefficient of friction for each number of sliding was averaged and shown in Table 4 and FIG.

  From Table 4 and FIG. 6, it can be seen that the friction coefficients of the compositions (I) to (IV) are relatively equivalent to the friction coefficients of the oily graphite and the W / O emulsion.

(3) Productivity evaluation A die-casting machine (manufactured by Ube Industries Co., Ltd.) with a clamping force of 1,650 tons is provided with a φ120 mm plunger tip, and injection speed (low speed 0.8 m / second, high speed 2.8 m / second) Second), a cycle time of 88 seconds, a molten metal temperature of 645 ° C., and a casting weight of 14.2 kg, the transmission axle case was cast.
In this evaluation, composition (III) and oil-based graphite were used as lubricants, and 5 milliliters per shot was dropped on the plunger tip to produce about 50,000 castings. Ignition state when molten metal was supplied, injection waveform The product defect rate was compared.
After the completion of production, the injection waveform and the product defect rate were comparable between the composition (III) and the oily graphite. However, when oily graphite is used, each time the molten metal is supplied, the lubricant ignites and the flame rises high, whereas when the composition (III) is used, the number of ignitions is less than that of oily graphite. It was about half, and the height of the flame was about half that of oil-based graphite.

  The oil-based plunger lubricant composition of the present invention is suitable for die casting using a molten metal made of aluminum, an aluminum alloy, a magnesium alloy, zinc, a zinc alloy, or the like. Using a large die casting machine of 1,000 tons or more, stable production of a cast product having a predetermined shape can be promoted under the condition of an injection speed of 2 to 3 m / sec.

1: Flammability evaluation apparatus 11: Box-shaped main body 13: Plunger tip 15: Molten metal inlet 17: Casting discharge part 2: Molten metal 3: Casting 5: Lubricant 6: Steel ball 7: Test piece 9: Heater

Claims (2)

An oil-based plunger lubricant composition comprising mineral oil, calcium sulfonate , wax , silicone, and aromatic phosphate ester .   The oil-based plunger lubricant composition according to claim 1, comprising a wax having a melt viscosity at 140 ° C. of 300 to 11,000 mPa · s.

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