JPH0515658B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a cement composition, and particularly to a cement composition which is used for sliding members and whose main components include a cementitious material, an ultrafine powder, a high-performance water reducer, and a solid lubricant. [Prior art] Conventionally, sliding parts such as machine tools and machine parts have been manufactured using water or water-based lubricants or no lubricants, especially machine tools that operate unmanned, vacuum and low temperature, etc. Since metal cannot be used for sliding parts such as pump parts and valves in special environments, synthetic resins such as diallyl phthalate resin, phenol resin, polyimide resin, and tetrafluoroethylene resin, and various materials such as glass fiber and carbon fiber are used. Composite materials that combine fibers or solid lubricants such as molybdenum disulfide, ethylene tetrafluoride, and graphite, and coatings of these materials on metal have been used. [Problems to be Solved by the Invention] However, the above-mentioned materials have problems such as poor heat resistance, weather resistance, use at low temperatures, organic solvent resistance, oil resistance, etc. due to the use of synthetic resin as a matrix. The dot was hot. In addition, some products have improved heat resistance, but it is only up to about 200°C, which is not sufficient, and there are also problems from an economic standpoint. The inventors of the present invention have investigated the above-mentioned problems in various ways, and found that by using cementitious material, ultrafine powder, high-performance water reducing agent, and solid lubricant as the main ingredients, it is possible to achieve excellent wear resistance and solve the above-mentioned problems. The inventors have discovered that an improved sliding member can be obtained and have completed the present invention. [Means for Solving the Problems] That is, the present invention is a cement composition whose main components are a cementitious material, an ultrafine powder, a high performance water reducer, and a solid lubricant. The present invention will be explained in more detail below. The cement material used in the present invention generally includes various Portland cements such as ordinary, early-strength, ultra-early-strength, white, or sulfate-resistant Portland cement, and mixed cements containing admixtures such as slag and fly ash. However, when mixed cement is used in a general curing method, the reaction continues for a long period of time, which is not desirable in terms of stability. , consideration must be given to pulverizing the mixed material and/or the cement to be mixed into a pulverized mixed cement. It is also possible to compensate for shrinkage using expansive cement, to develop the required strength in a short time with rapid hardening cement, and to use a gypsum-based high-strength admixture. The expanding component of the expanding cement is Etrin guide type, such as "Denka" manufactured by Denki Kagaku Kogyo Co., Ltd.
CSA # 20'' and calcined CaO are preferred, and even among calcined CaO, they are calcined at 1100 to 1300℃ and have an average crystal diameter of 10μ.
The following are particularly preferred. Rapid-hardening cement contains calcium aluminate-based rapid-hardening components, such as various types of calcium aluminate alone or a mixture of calcium aluminate and calcium sulfate.
There are cements containing ``Denka ES'' manufactured by Onoda Cement Co., Ltd., and ``Jet Cement'' manufactured by Onoda Cement Co., Ltd. High-strength admixtures are gypsum-based, such as "Denka Σ-1000" manufactured by Denki Kagaku Kogyo Co., Ltd. and "Asano Super Mix" manufactured by Nippon Cement Co., Ltd. The ultrafine powder has an average particle size that is at least one order of magnitude lower than that of the above-mentioned cementitious material, and it is particularly preferable that the average particle diameter of the ultrafine powder is two orders of magnitude lower from the viewpoint of the fluidity properties of the kneaded material. Specifically, silica dust (silica fume) and siliceous dust, which are produced as by-products during the production of silicon, silicon-containing alloys, and zirconia, are particularly suitable, and calcium carbonate, silica gel, opalescent silica, fly ash, slag, and titanium oxide are particularly suitable. , aluminum oxide, etc. can also be used. In particular, opalescent silica, fly ash,
The use of ultrafine powder obtained by pulverizing slag using a jet mill equipped with a classifier is effective in improving curing shrinkage. The amount of ultradifferentiation used is preferably 40 to 5 parts by weight based on 60 to 95 parts by weight of the cementitious material, and more preferably 35 to 10 parts by weight based on 65 to 90 parts by weight. If it is less than 5 parts by weight, the effect of developing high strength is small, and
If the amount exceeds 40 parts by weight, the fluidity of the kneaded product will be significantly reduced, making it difficult to mold and developing insufficient strength. What is a high performance water reducing agent (hereinafter simply referred to as a water reducing agent)?
It is a surfactant that has a large dispersing power without causing too much delay in setting or excessive air movement even when added to cement in large quantities. Examples include those whose main components are salts, high molecular weight lignin sulfonates, polycarboxylate salts, etc. A water reducing agent is necessary to obtain a kneaded product with a low water ratio, and the conventional amount used is 0.3 to 1% by weight based on cement, but in the present invention,
It is desirable to add it in a larger amount. Specifically, a mixture of cementitious material and ultrafine powder 100
It is used up to about 10 parts by weight as a solid content, and if it is added in an amount larger than that, it will adversely affect the curing reaction. A particularly preferable addition amount is 1
~5 parts by weight. By using such a water reducing agent in combination with ultrafine powder, it is possible to obtain a fluid kneaded material that can be molded by a conventional method even if the ratio of water cementitious material to ultrafine powder is 25% or less. The term solid lubricant used in the present invention refers to a solid that has a lubricating effect on its own, protects surfaces from damage during relative motion, and reduces friction and wear. Examples of these include inorganic substances with a layered structure such as molybdenum disulfide, graphite, boron nitride, mica, and talc; inorganic substances with a non-layered structure such as calcium fluoride, barium fluoride, and lead oxide; lead, cadmium, These include soft metals such as white metal, organic polymer compounds such as polytetrafluoroethylene and polyamide fluorine resin, and organic layered crystal structures such as phthalocyanine. These solid lubricants can be used alone or in combination of two or more. The amount of solid lubricant used varies depending on the particle size and specific gravity of the solid lubricant.
The amount is 1 to 100 parts by weight, preferably 3 to 80 parts by weight. If it is more than 100 parts by weight,
Wear resistance, fluidity, and strength properties are reduced. If it is less than 1 part by weight, lubricity is poor. In addition to the above materials, aggregates, fibers including nets, etc. can be used in combination. The aggregate may be those conventionally used in the preparation of general concrete in the field of civil engineering and construction, but harder materials, specifically those with a Mohs hardness of 6 or more, preferably 7 or more, or Knoop It is preferable to use an indenter having an indenter hardness of 700 Kg/mm ² or more, more preferably 800 Kg/mm ² or more, since the strength, that is, the wear resistance can be significantly improved. Examples of materials that meet this standard include silica, emery, pyrite, magnetite, yellow jade, lawsonite, corundum, fenasite, spinel, beryl, chrysosite, tourmaline, granite, andalusite, crossite, zircon, These include calcined bauxite, boron carbide, tungsten carbide, ferrosilicon nitride, silicon nitride, fused silica, fused magnesia, silicon carbide, cubic boron nitride, and ceramic crushed products. The amount of aggregate used is usually selected within 5 times the weight of the total of cementitious material and ultrafine powder. Fibers include steel fibers, stainless steel fibers, copper fibers, various alloy fibers, various natural and synthetic mineral fibers such as asbestos and alumina fibers, carbon fibers, glass fibers, and polypropylene, vinylon, acrylonitrile, aromatic polyamides, and cellulose. Examples include natural or synthetic organic fibers.
Steel rods and FRP rods are also used for reinforcement. The water used in preparing the mixture in the present invention is necessary for molding, but in order to obtain a high-strength hardened product, it is best to use as little water as possible. 12.5 per part
It is preferably from 15 to 35 parts by weight, more preferably from 15 to 35 parts by weight. If the amount of water is more than 40 parts by weight, it is difficult to obtain a high-strength cured product;
If the amount is less than parts by weight, it becomes difficult to perform molding by ordinary pouring or the like. The above materials can be mixed and kneaded by any method as long as they can be mixed and kneaded uniformly.
There is no particular restriction on the order of addition. Also,
It is also possible to place aggregate in advance and pour cement paste and mortar afterwards. Various types of curing are possible for curing the molded product, and any of the following methods can be adopted: normal temperature curing, normal pressure steam curing, high temperature and high pressure curing, and high temperature curing.If necessary, a combination of these curing methods may be used. The composition obtained by the above method can be used as it is as a sliding member, or can be coated on the surface of a metal to impart sliding properties to the metal. Methods for forming the sliding member include pouring, compaction press molding, and extrusion molding, and coating on metal may be performed by any method such as brushing, spatula, troweling, spraying, and spraying. Furthermore, if surface finishing is required, finishing such as wrapping or polishing can be performed. In addition, it is also possible to use such a sliding member together with a water lubricant, a latex-based lubricant, or even a solid lubricant dispersed in water.
The effect will be greater. Cement compositions with such sliding properties can be used for sliding surfaces of machine tools, mechanical parts such as bearings, brake shoes, gears, packings, and tools such as surface plates, as well as for press molding and injection molding. It can be used for molds such as molding, and it can also be used for building materials that require sliding properties, such as the floors of mobile bookshelves and door panels. [Example] The present invention will be explained below with reference to Examples. Example 1 Based on the formulation shown in the table, the mixture was kneaded for 3 minutes using a mortar mixer, and the flow value was measured. or,
The mixture was kneaded in the same manner and poured into a 4 x 4 x 16 cm mold to form a specimen. Demolded 24 hours after injection,
After curing at 50°C and 80% RH for 4 days and cooling to room temperature, compressive strength was measured using a Shimadzu universal testing machine. Further, the friction coefficient and the amount of wear were measured using a friction and wear tester EFM--EN/EH manufactured by Toyo Baldwin Co., Ltd., which was prepared in the same manner as the specimen for strength measurement.
The measurement conditions at that time were as follows. Compatible material: Material, GG22 (casting), surface roughness 1μ or less Specimen: Surface roughness 1μ or less Rotation speed: 2m/s Pressure load: 20Kg ^f / cm ² Atmosphere: Air, 20℃ Test time: 3 hours The results are also listed in the table. <Materials used> Cement: Denki Kagaku Kogyo Co., Ltd., ordinary Portland cement ultrafine powder: Japan Heavy Chemical Industry Co., Ltd., silica hume Water reducer: Daiichi Kogyo Seiyaku Co., Ltd., "Cellflow 110P" Aggregate: Sumitomo Metals Manufactured by Mining Co., Ltd., emery, 0.3-1.2mm
Solid lubricant A: boron nitride, manufactured by Denki Kagaku Kogyo Co., Ltd.
BN B: Molybdenum disulfide, manufactured by Cryax Molybdenum C: Graphite, manufactured by Wako Pure Chemical Industries, Ltd. Reagent D: Talc, “SW” manufactured by Nippon Talc Co., Ltd. E: Ethylene tetrafluoride, manufactured by Daikin Industries, Ltd.

〔Effect of the invention〕

As described above, the cement composition of the present invention exhibits ultra-high strength and excellent wear resistance, and since it is based on inorganic materials, it is heat resistant, has excellent organic solvent and oil resistance, and is rust-proof for sliding members. can be obtained.

[Brief explanation of the drawing]

The drawing is a cross-sectional view of an example of a press mold made using the cement composition of the present invention. Code 1: frame, 2: concrete member.

Claims (1)

[Claims] 1. A cement composition whose main components are a cementitious substance, an ultrafine powder, a high-performance water reducing agent, and a solid lubricant.