JPH026600A - Water-soluble lubricant for plastic working - Google Patents

Abstract

PURPOSE:To avoid work environment pollution and health hazard, by compounding two dibasic acid alkali metal salts and water-soluble polymers, thereby providing superior lubricity and releasability to those of graphite as lubricant for plastic working. CONSTITUTION:Water-soluble lubricants for plastic working are prepd. by compounding 0.1-30wt.%, pref. 5-15wt.%, two dibasic acid alkali metal salts (esp. Na salt is pref.), and 0.01-20wt.%, pref. 0.1-5wt.%, water-soluble polymers (e.g., hydroxyethylcellulose). Combinations of two kinds of dibasic acid are phthalic acid and adipic acid, phthalic acid and glutaric acid, phthalic acid and fumaric acid, isophthalic acid and adipic acid, isophthalic acid and glutaric acid, isophthalic acid and fumaric acid, terephthalic acid and malonic acid, glutaric acid and malonic acid, glutaric acid and fumaric acid, glutaric acid and malic acid, and fumaric acid and malonic acid. The wt. ratio between the two dibasic acid alkali metal salts in these combinations is 1:9-9:1, pref. 3:7-7:3.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a water-soluble lubricant for plastic working.

This lubricant is suitable for plastic processing, i.e. forging, extrusion, rolling,
It is used in place of graphite-based lubricants for the purpose of mold release during metal processing such as pressing and wire drawing, especially hot or warm forging and hot extrusion that use graphite-based lubricants. It is useful as a non-graphite lubricant.

[Conventional technology]

Oil-based or water-dispersed graphite is usually used as a lubricant for plastic working of metals.

The former is made by dispersing graphite in a mixture of mineral oil, extreme pressure additives, waxes, etc., but since most of the processing is done hot, there is a risk of ignition and smoke generation. There are major problems in terms of work environment and health. The latter is made by adding extreme pressure additives to water and dispersing graphite. The lubricity is the same as that of the former oil fraction, there is no flammability problem, and workability is slightly improved, but as long as graphite is used, it will not contaminate workers and the working environment with black. However, health issues remain.

In order to solve these problems in the working environment, attempts have been made to develop lubricants for plastic working that do not use graphite. For example, a lubricant containing a glass composition in an alkali metal salt of an aromatic carboxylic acid (Japanese Patent Application Laid-open No. 6O-1293), a lubricant using an alkali metal salt of phthalic acid (Japanese Patent Application Laid-Open No. 58-1988)
8489) etc. However, even with these lubricants, in the former case, the glass composition tends to accumulate in the recesses of the mold, causing underfilling, and good lubricity cannot be obtained when the mold temperature is low. There are problems such as the mold cannot be easily cleaned with water, and spraying the glass composition is not good for the health of the workers. The latter has the advantage of being less toxic, causing no particular health problems, and the mold can be easily washed with water, but it is said to have slightly poorer lubricity than graphite and is more likely to seize. Disadvantages are identified in use.

[Problem to be solved by the invention]

Graphite-based lubricants, which are used exclusively as lubricants for plastic processing, are known to contaminate workers and the working environment with black, as mentioned above, and may be harmful to health. In this case, there are problems such as the risk of ignition.

Therefore, it has good lubricity, no pollution (non-flammable,
There is a need for a lubricant that is easy to clean and has no health concerns. Furthermore, lubricants are generally used diluted with water, but in recent years there has been a demand for lubricants to have a certain level of performance even when highly diluted.

An object of the present invention is to provide a lubricant for plastic working that can satisfy such requirements.

[Means to solve the problem]

In the present invention, the alkali metal salts of two types of dibasic acids are
30 II% and 0.01 to 20% by weight of a water-soluble polymer compound, and the combinations of two dibasic acids include orthophthalic acid and adipic acid, orthophthalic acid and glutaric acid, Orthophthalic acid and fumaric acid, isophthalic acid and adipic acid, isophthalic acid and glutaric acid, isophthalic acid and fumaric acid, terephthalic acid and glutaric acid, terephthalic acid and fumaric acid, terephthalic acid and malonic acid, glutaric acid and malonic acid, glutaric acid and fumaric acid, glutaric acid and malic acid, and fumaric acid and malonic acid.

The lubricant of the present invention may further contain additives selected from particulate minerals, extreme pressure additives, preservatives, corrosion inhibitors, and antifoaming agents.

Lubricants for plastic working, especially hot forging, cannot be used because the mold temperature is as high as approximately 300°C, so they cannot be used if they decompose and disappear at temperatures around this temperature. However, it is desirable that it disappear while in contact with the metal to be forged at a temperature of 1000°C or higher.

Graphite is useful in this respect, but alkali metal salts of dibasic acids are white and exhibit similar properties. Here, metal soaps, that is, metal salts of saturated fatty acids, which are monobasic acids, are often used as lubricants for plastics, but these cannot be said to be useful as lubricants for plastic processing because they cannot be applied uniformly. .

Examples of the dibasic acids mentioned above include saturated fatty acids such as succinic acid and adipic acid, unsaturated fatty acids such as fumaric acid and maleic acid, and aromatic carboxylic acids such as phthalic acid and isophthalic acid. When salt is used as the main lubricant component for the purpose of the present invention, the coefficient of friction is small;
Therefore, underfilling is less likely to occur, but seizure is more likely to occur.
On the other hand, there is the problem that although seizure does not occur, underfilling is likely to occur, making it impossible to obtain fully satisfactory results.

However, it has been found that by using a mixture of two types of alkali metal salts of dibasic acids, the above problems can be completely solved and good results can be obtained. The reason for this is that when the mixture is applied from an aqueous solution state to a mold and crystallized, the crystals become disordered compared to a single 'sit, that is, the mixture becomes crystals with lower binding energy. The lubricity is expressed early due to the melting point depression phenomenon, and the remaining amount of the active ingredient due to thermal decomposition increases because the substance with a low thermal decomposition temperature decomposes first, and then the substance with a high thermal decomposition temperature decomposes,
Alternatively, since the disorder of the crystals is thought to exhibit collapse similar to layered grooves, it is inferred that this results in excellent lubricated mold release performance. However, although the combination of the two aforementioned dibasic acids gives good results, different combinations of these dibasic acids, such as terephthalic acid and adipic acid, isophthalic acid and malonic acid, adipic acid and glutaric acid, However, the specific combination defined in the present invention provides an effect that meets the objective.

The dibasic acid is used in the form of an alkali metal salt in order to obtain thermal stability, and particularly in order to obtain water solubility as a product, it is difficult to use an alkaline earth metal salt. As the alkali metal salt, sodium salt, potassium salt, and lithium salt are preferable, and sodium salt is particularly desirable.

The alkali metal salt of dibasic acid is contained in the composition as a main component of the lubricant in an amount of 0.1 to 30! ifi%, preferably 5-15
It must be contained in an amount of % by weight.

This is because if it is less than 0.1% by weight, the low coefficient of friction necessary for a lubricant cannot be obtained, and if it exceeds 30% by weight, a stable product cannot be obtained. Further, the weight composition ratio of the alkali metal salts of the two types of dibasic acids is 1:9 to 9:1,
The ratio is preferably 3:3 to 7:3.

The lubricant is generally applied to the mold by spraying. At this time, it is possible to apply only the main lubricant, but a water-soluble polymer compound is used as an adhesive to form a more uniform film. Examples of water-soluble polymer compounds include hydroxyethyl cellulose, carboxymethyl cellulose, sodium polycarboxylate, and ammonium polycarboxylate. The amount of water-soluble polymer compound added is preferably 0.01 to 20% by weight, preferably 0.1 to 5% by weight. This is 0.0
If it is less than 1% by weight, it will not be effective as an adhesive;
This is because if the amount exceeds % by weight, the viscosity increases significantly, making handling of the product complicated.

The above composition can be used satisfactorily as a lubricant for plastic working, but when processing is carried out under harsher operating conditions, there is a possibility that seizure may occur. Particulate minerals and extreme pressure additives may also be added.

Fine particle minerals include layered mica, talc, kaolin,
Suitably, at least one of the fibrous minerals sepiolite, attapulgite, calcium carbonate, calcium sulfate, and barium sulfate is added in an amount of 0.1 to 20% by weight.

Furthermore, it is also possible to add a bactericide for the purpose of preventing corrosion, a corrosion inhibitor for the purpose of rust prevention, and an antifoaming agent for the purpose of suppressing foaming during spraying.

The water-soluble lubricant for plastic working of the present invention may be used as an undiluted solution, but it is preferably 10 times to 50 times
Dilute it twice and use it. From a performance standpoint, it is important to determine whether the amount of solids applied is appropriate, and the amount applied can be increased or decreased by increasing the dilution ratio, but due to constraints such as the timing of application and processing and the shape of the nozzle, It is preferable to change the amount of lubricant solid content applied by adjusting the dilution ratio. Incidentally, the composition concentration explained above is conventionally the concentration before dilution. Any method may be used to apply the resin to the mold, but it is generally preferable to apply by spraying. Further, it may be used as a lubricant for plastic working under hot forging or other forging conditions, or during extrusion.

〔Effect of the invention〕

By using the composition of the present invention as a lubricant for plastic working, it is possible to obtain lubricating performance and mold release properties superior to those of graphite, and since it is a white product, there is no contamination of the working environment, and it is good for the health of workers. It is also excellent, and there are no problems with cleaning.

〔Example〕

Next, the present invention will be further explained by examples. Note that parts and percentages in the examples are based on weight unless otherwise specified.

Example 1 The friction coefficient was determined by a ring compression experiment.

φ120 x 50m mold (SKD 61, hardened)
Heat the upper and lower molds to about 270°C, and spray apply lubricant 10- diluted 30 times to the surfaces of the upper and lower molds that will come into contact with the ring (pressure 5 kg/cd). Meanwhile, φ60×φ3
A 0.times.15 crane ring (345C material) is heated to 1000.degree. C. in an electric furnace in an Ar atmosphere. The rate of decrease in the height of the mold and ring (processing degree) and the rate of change in the inner diameter are calculated using the energy method by Kudo J (Proc, 5th, Japan Na
t, Cong.

The coefficient of friction was determined by plotting on the theoretical curve determined by Appl, Mech, (1955), 75).

~Lubricant composition used in the experiment~ (Same composition in Example 2.3) Dibasic acid 11.0 parts Sodium hydroxide 7.5 parts Hydroxyethylcellulose 2.0 parts Talc
0 or 5 parts water remaining ~ dibasic acid used in the experiment ~ (same composition in Example 2.3) The numbers in the table indicate sample disease, and the combination of two dibasic acids in the same parts by weight. In this example, talc is not included. Among these, 1 to 13 are examples, and 14 to 16 are comparative examples.

The results are shown in Table 1 below.

(However, when the processing degree is 40%) As a result of the ring compression test, the preferred blended composition of two dibasic acids (llhl~13) has lower friction than the unfavorable blended composition (llhl~16). The coefficients are shown.

Furthermore, when 5 parts of fine mineral particles were added to the N15 composition, the coefficient of friction showed a low value of 0.34.

As a comparative example, tests were also conducted in which fumaric acid or adipic acid was used alone as the dibasic acid, and the friction coefficients thereof showed high values of 0.41 and 0.66.

Example 2 The presence or absence of seizure property was confirmed by a backward extrusion experiment. φ3
8. Heat a punch type (SKD 61, hardened) of a drafting device to about 300°C, and automatically spray lubricant diluted 10 times (4 + r/cd, 2 d/sec). 0
．． Spray for 3 seconds x 4 times (2.4-1 in total, but there is a lot of loss). On the other hand, a test piece (345C material) of φ36.5×50 μl was heated to 1000° C. in an electric furnace in an Ar atmosphere. The punch mold and test piece were set in a 120 ton hydraulic press and compressed. Repeat the same operation five times with different test pieces, and observe the condition of the punch mold after completion. The device was devised so that even if the test piece and punch die were sewn together, they could be separated when pulled out. For comparison, the lubricant was applied to the punch type using a hand spray with a 5-fold diluted solution. (in the table)
). Incidentally, the grades marked with '' in the table are examples of compositions containing 5 parts of talc. Furthermore, as another comparative example, a test was also conducted in which fumaric acid was used alone as the dibasic acid.

The results are shown in Table 2 below.

When using fumaric acid alone or a combination of two unfavorable dibasic acids (N114 to 16.15"), the punch type R
Vertical scratches appeared on some parts due to burning. However, in the case of preferable formulations (numbers 1 to 13) and when the formulation included fine-grained minerals (1'h5'), vertical flaws due to seizure did not occur.

Example 3 We conducted an evaluation using an actual machine.

Hot forging of automobile parts (material 345G) was carried out using a 16"σΩ ton press and a 6000 ton press (material temperature approx. 1250℃, mold temperature approx. 350-400℃).
℃).

The spray used was an airless automatic spray with a pressure of 5 kg/-, and the spray was applied for about 2 to 3 seconds while the mold was open. The dilution ratio is 30 times.

The results are shown in Table 3 below.

Evaluation criteria ◎: Very good ○: Good △: Slightly poor ×: Poor As a result of the actual machine evaluation, the lubricant of the present invention (in this example, m5
．． 6) has superior performance in terms of lubricity, mold releasability, and anti-seizure properties compared to a water-soluble lubricant containing two unfavorable dibasic acid salts or a dibasic acid alone; It was confirmed that workability was also improved.

Claims (1)

[Claims] An aqueous composition containing 0.1 to 30% by weight of an alkali metal salt of one or two types of dibasic acids and 0.01 to 20% by weight of a water-soluble polymer compound; The combinations of orthophthalic acid and adipic acid, orthophthalic acid and glutaric acid, orthophthalic acid and fumaric acid, isophthalic acid and adipic acid, isophthalic acid and glutaric acid, isophthalic acid and fumaric acid, terephthalic acid and glutaric acid, and terephthalic acid and Water-soluble plastic processing lubricants which are fumaric acid, terephthalic acid and malonic acid, glutaric acid and malonic acid, glutaric acid and fumaric acid, glutaric acid and malic acid, and fumaric acid and malonic acid.