JP5526415B2 - Aqueous release lubricant composition - Google Patents

Description

  The present invention relates to a water-based release lubricant composition that imparts lubricity and releasability by directly applying to a high temperature object such as a release / sliding member by a method such as spraying or brushing. About.

  Examples of mold release / sliding fields that require lubrication in a high temperature range include workpieces and molds in plastic processing between warm and hot temperatures, and are attached to the outlet of a molten metal container for iron making. There is a brick part of the sliding opening and closing device. For example, a water-based release lubricant is conventionally applied to these release / sliding members, but the moisture contained in the applied release lubricant is high-temperature release / slide members. There was a problem in that a good lubricant coating film could not be formed because the water vapor generated instantly evaporated and the generated water vapor repelled the droplets of the release lubricant.

  As a method for solving this problem, for example, Patent Document 1 describes a method in which a surface treatment agent containing an inorganic water-soluble adhesive is applied in advance to the surface of a release / sliding member to which an aqueous lubricant is applied. Has been. However, in this method, the surface of the mold release / sliding member needs to be pre-treated in advance, and another type of mold release lubricant is applied on the surface of the pre-treated to form two treatment layers. For example, there is a drawback that the application work to the high-temperature mold release / sliding member becomes extremely complicated.

  Silicone oil is generally used as a lubricant release agent for high-temperature release / sliding members such as molds. For example, Patent Document 2 proposes the use of a water-soluble emulsion in which a specific chelating agent is contained in organopolysiloxane for releasing into a high-temperature mold. However, this method is intended to prevent contamination by reducing adhesion to a high-temperature mold, and does not indicate that the adhesion of a water-soluble release lubricant can be improved.

Japanese Patent No. 3931054 JP 2003-275845 A

  In view of the above-described problems of the conventional aqueous release lubricant, the present invention provides an aqueous release by water vapor generated by evaporation of moisture when applied to the surface of a high-temperature object (release / sliding member). An object of the present invention is to provide an aqueous release lubricant composition that can prevent the droplets of the mold lubricant from being repelled and can form a good release lubricant film on the surface of an object to be coated.

  In order to achieve the above object, the inventor applied a water-based release lubricant composition as a result of repeated investigations on conditions under which a good release lubricant film can be formed when applied to a high-temperature release / sliding member. When bubbles of water vapor generated at the interface with the high-temperature mold release / sliding member are released, they are released when the interfacial tension at 25 ° C. of the aqueous release lubricant composition is within a specific range. It has been found that it adheres to the surface of the high-temperature mold release / sliding member without any failure, and has completed the present invention.

  That is, the aqueous release lubricant composition provided by the present invention is an aqueous release lubricant composition comprising a silicone surfactant, a solid lubricant, and a water-soluble resin, and the silicone surfactant 0.001 to 0.1% by mass, 10 to 50% by mass of a solid lubricant, 1 to 5% by mass of a water-soluble resin, and a surface tension at 25 ° C. of 40 to 60 mN / m. .

  In the aqueous release lubricant composition according to the present invention, the silicone surfactant is preferably any one of polydimethyl silicone, fluoroalkyl-modified silicone and organo-modified silicone. The solid lubricant is preferably graphite.

  According to the water-based mold release lubricant composition of the present invention, when applied to a high temperature coated object exceeding 600 ° C., the applied droplets are not repelled, and the surface of the coated object has good mold release lubrication. A film can be formed. Accordingly, since the water-based release lubricant composition can be directly applied to a high-temperature object to be coated, it is troublesome to apply a ground treatment agent to the object to be coated, cool it once, and then reheat it. This eliminates the need for operation, eliminates energy loss, and greatly improves the efficiency of mold release lubrication at high temperatures.

  The water-based release lubricant composition of the present invention comprises a silicone surfactant, a solid lubricant, and a water-soluble resin as main components, and water as a solvent. The surface tension at 25 ° C. is adjusted to a range of 40 to 60 mN / m by addition. By controlling the surface tension to 40 to 60 mN / m by adding a silicone surfactant, droplets of the water-based release lubricant composition applied to the high-temperature release / sliding member are not repelled. -A good release lubricant film can be formed by adhering to the surface of the sliding member.

  The silicone surfactant used in the water-based release lubricant composition of the present invention is not particularly limited, and polydimethyl silicone, a fluoroalkyl-modified silicone in which a part of the methyl group of polydimethyl silicone is replaced with a fluoroalkyl group, An organo-modified silicone in which a part of the methyl group of polydimethyl silicone is replaced with a primary amine can be used. Moreover, in order to improve the defoaming property and dispersibility in water, a silicone-based surfactant containing polyoxyethylene / octylphenyl ether, mineral oil, or the like can also be used.

  When any silicone surfactant is used, it is important to control the surface tension of the water-based release lubricant composition within a range of 40 to 60 mN / m by adding the silicone surfactant. From the viewpoint of thermal stability, polydimethylsilicone, trifluoropropyl-modified silicone that is one kind of fluoroalkyl-modified silicone, primary amine-modified silicone that is one kind of organo-modified silicone, and the like are preferably used. it can. Among them, polydimethyl silicone is particularly preferable because it is excellent in heat resistance and chemical resistance.

  The blending amount of the silicone surfactant is in the range of 0.001 to 0.1% by mass with respect to the total amount of the water-based release lubricant composition. When the amount of the silicone surfactant is less than 0.001% by mass, it is difficult to obtain the surface tension reducing effect of the aqueous release lubricant composition, and it is difficult to obtain the surface tension in the range of 40 to 60 mN / m. . Further, even if the silicone surfactant is added in an amount of more than 0.1% by mass, the effect of reducing the surface tension is saturated, so that further reduction of the surface tension cannot be obtained and the cost increases. .

  The water-based release lubricant composition of the present invention contains a solid lubricant. As the solid lubricant, known solid lubricant powders generally used for the purpose of mold release and lubrication can be used. For example, graphite (graphite), tetrafluoroethylene (PTFE), melamine cyanuric acid (MCA) ), Talc (talc), mica (mica), molybdenum disulfide, tungsten disulfide, and the like can be suitably used. Among them, graphite is a soft scaly crystal structure, and is particularly preferable because it easily forms a lubricating surface by sliding on an object to be coated.

  The blending amount of the solid lubricant is 10 to 50% by mass with respect to the total amount of the water-based release lubricant composition. When the blending amount of the solid lubricant is less than 10% by mass, the lubricating action of the release lubricant film becomes insufficient. On the other hand, when the blending amount of the solid lubricant is more than 50% by mass, the aqueous release lubricant composition becomes pasty, so that it is difficult to apply to the coating object.

  The aqueous release lubricant composition of the present invention contains a water-soluble resin in order to make the above-described solid lubricant a coating film on the surface of the object to be coated. The water-soluble resin is not particularly limited, and those conventionally used for the same purpose, for example, carboxymethyl cellulose, hydroxyethyl cellulose and the like can be used. In the aqueous release lubricant composition of the present invention, sodium alginate can also be used as a water-soluble resin.

  The blending amount of the water-soluble resin needs to be 1 to 5% by mass with respect to the total amount of the water-based release lubricant composition. When the blending amount of the water-soluble resin is less than 1% by mass, it is difficult to form a coating film on the surface of the member to be coated. Further, if the blending amount of the water-soluble resin is more than 5% by mass, the lubricating action of the release lubricating film becomes insufficient, which is not preferable.

  In general, water-based release lubricant compositions tend to settle solid lubricant powder over time, so thickening bentonite, hectorite, and smectite that have been hydrotreated for the purpose of preventing sedimentation and improving redispersibility. It can be contained as an agent. The blending amount of the thickener can be appropriately determined according to the type and blending amount of the water-soluble resin to be used. However, if the blending amount is too large, it becomes a paste that is a characteristic of the water-soluble resin. It needs attention because it affects. Furthermore, various additives such as preservatives, dispersants and antifoaming agents for the purpose of long-term stability can be appropriately blended.

  The aqueous release lubricant composition of the present invention can be produced by weighing a predetermined amount of each of the above-described components and, for example, stirring and mixing according to the following procedure, but is not particularly limited to the following procedure. . For example, a predetermined amount of a silicone surfactant, a solid lubricant, a water-soluble resin, a solvent (water), and an antifoaming agent, a dispersing agent, an antifoaming agent, and the like are weighed. Next, the aqueous release lubricant composition of the present invention can be obtained by mixing these raw materials and stirring and mixing and dispersing until a uniform liquid is obtained using, for example, a dissolver type stirrer.

  While using any of polydimethyl silicone (surfactant 1), trifluoropropyl-modified silicone (surfactant 2), and primary amine-modified silicone (surfactant 3) as the silicone-based surfactant, Graphite powder was used as a solid lubricant, hydroxyethyl cellulose was used as a water-soluble resin, and water was used as a solvent to prepare water-based release lubricant compositions of Samples 1 to 7 shown in Table 1 below.

  That is, each of the above components is weighed so as to have the composition shown in Table 1 below, stirred and mixed at 1200 rpm for 30 minutes with a dissolver type stirrer, and each of the water-based mold release lubricating compositions of Samples 1-7. Was made. About each water-system mold release lubricating composition of the obtained samples 1-7, surface tension was measured by the test method based on JISK2241, using Mr. Dunois surface tension meter, and the obtained result was each water system release. It was shown in the following Table 1 together with the blending composition of the mold lubricant composition.

  Next, the film-forming properties (adhesiveness) of each of the aqueous release lubricant compositions of Samples 1 to 7 were evaluated by the following evaluation method. That is, an air spray (manufactured by Meiji Machinery Co., Ltd., nozzle diameter 1.0 mm, mist) was applied to a fire-resistant brick heated to the surface temperature shown in Table 2 below and inclined at 60 °. Application pressure was 0.35 MPa). The refractory brick was heated in an electric furnace, and the surface temperature of the refractory brick was measured using a radiation thermometer.

  The evaluation results of the film-forming properties (adhesiveness) obtained are shown in Table 2 below together with the surface temperature of the refractory brick. In addition, the standard of evaluation was that the water-based release lubricant composition droplets sprayed from the air spray adhered to the surface of the refractory brick without being repelled and formed a film, and the spray was sprayed from the air spray. More than 50% and less than 80% of the droplets adhere to the surface of the refractory brick without being repelled, and less than 50% of the droplets sprayed from the air spray adhere to the surface of the refractory brick without being repelled. What formed the film was set as x.

  As can be seen from the above results, each of the water-based release lubricant compositions of Samples 1 to 5 which are examples of the present invention has a surface tension as low as 40 to 60 mN / m and the surface of the refractory brick heated to a high temperature. When applied by spraying, the droplets did not repel and adhered to the surface, and a good release lubricant film could be formed. On the other hand, each of the water-based release lubricant compositions of Samples 6 to 7 as a comparative example does not contain a silicone surfactant or its blending amount is too small, so that the surface tension becomes higher than 60 mN / m, and the fire resistance If the surface temperature of the brick was not 400 ° C. or lower, it could adhere and form a release lubricating film.

Claims (1)

A water-based release lubricant composition for forming a water-based release lubricant film on a high-temperature coating object exceeding 600 ° C., comprising 0.001 to 0.1% by mass of a silicone surfactant, a solid lubricant 10 to 50% by mass of graphite and 1 to 5% by mass of hydroxyethyl cellulose as a water-soluble resin , and the silicone-based surfactant is any one of polydimethylsilicone, fluoroalkyl-modified silicone and organo-modified silicone, An aqueous release lubricant composition characterized in that the surface tension at 25 ° C. is controlled to 40 to 60 mN / m by the addition of a silicone surfactant .