JPS6230063B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improved mold sand disintegrator. Water glass molds and cement molds are extremely popular in casting manufacturing because they are easy to mold and the material costs are low. After the sand has solidified and the mold is destroyed to take out the product, the molding sand has poor collapsibility and it takes time to remove the sand, which requires a pneumatic hammer, a large hammer, etc. This causes worker fatigue and requires a great deal of effort, and the impact of the hammer can cause cracks in the casting, resulting in defective products, which sometimes impedes productivity. This is the biggest drawback of water glass-based molds and cement-based molds. has been used as a disintegrant, but no significant results have been obtained in terms of improving disintegration. This is because if a large amount of powder disintegrants such as wood flour are used, the disintegration properties will improve, but as the surface area of the powder increases, the binding force of the binder water glass and cement will decrease, and the strength of the mold at room temperature will decrease. It becomes weak and the surface stability of the mold is poor, making it difficult to handle. Water-soluble auxiliary binders such as sucrose are dissolved in the water contained in the water glass, increasing the binding power of the sand, reducing the fluidity of the sand, and making molding time-consuming. In addition, water glass absorbs water into the water-soluble auxiliary binder, so the kneaded sand dries quickly and the usable life of the sand is shortened, and in the case of CO ₂ gas type sand, the kneaded sand cannot be stored. In the case of cement molds, molasses is used, but the sand generates heat, which causes a lot of wear and tear on the wooden mold (the model used to make the mold) and produces an unpleasant odor. When sucrose and glucose become liquid sugar, their effectiveness as disintegrants decreases.Disintegrants that absorb water during or after the mixing of molding sand are difficult to dehydrate, and due to the residual water, the strength of the mold decreases and the surface of the mold deteriorates. Stability also deteriorates. Therefore, sucrose, glucose, starch, etc. are scattered in the form of powder or granules between the grains of sand in the mold, and when poured, they are heated by hot water, burnt, and carbonized, and are generated during the process of solidifying the casting. It exerts a buffering effect by absorbing compressive force, but when dissolved in water, this buffering effect decreases, causing the molding sand to tighten and become less collapsible. Especially the core (the inner mold of the casting)
This tendency is strong. Furthermore, molds using water-soluble auxiliary binders are hygroscopic, and if the molds are not sufficiently dried, gas defects will occur in the castings. Up until now, using too many disintegrants has improved disintegration, but it has also increased material costs, deteriorated mold strength and surface stability, and increased gas generation due to combustion of combustible materials during pouring, resulting in castings with gas defects. Many defects occur due to Traditionally, water glass-based molding sand and cement-based molding sand were disposable because they were cheap, but as regulations on industrial waste disposal became stricter, the cost of waste disposal became a larger proportion of the manufacturing cost of castings. As the recovery and recycling of sand has become an urgent need, recycling equipment has become widely installed. However, with poorly collapsible sand, a lot of hardened binder sticks to the surface of the sand grains, and the sand grains are tightly bound together, forming large sand blocks. This takes a lot of time and effort, such as crushing it using a crusher and removing foreign matter stuck to the surface of the sand grains using a sand grain polisher, but the sand grains are crushed and the recovery rate is poor. It is treated as industrial waste. Powder, granular petroleum-based wax, powder, granular plant-based wax, powder, granular animal-based wax (hereinafter, the above various waxes may be collectively referred to as powder or granular wax),
Powder, granular low molecular weight polyolefin resin, powder, granular atactic polypropylene resin, powder, granular chemical structure unknown so-called kettle residue resin (hereinafter, the above various resins and resin-like substances are collectively referred to as powder, granular polyolefin) Molding sand disintegrants consisting of one or more types of resins (sometimes expressed as resins, etc.) exhibit remarkable disintegrability and have a high rate of sand reuse, but because they are soft, they are crushed during kneading. It adheres to the kneading machine and softens in the summer or at high temperatures in the workplace, making it difficult to handle, and it also burns during pouring, creating an unpleasant odor, which makes the working environment worse. The present invention uses powders, granular petroleum waxes, powders, granular vegetable waxes, powders, granular animal waxes, powders, granular low molecular weight polyolefin resins, powders, granular Atactic polypropylene resin, powder, granular chemical structure unknown so-called kettle residue resin material to increase the hardness and use as an unpleasant odor deodorizer powder, granular graphite, wood powder, rice husk powder, granular crushed material, Grain flour, ground granules,
One or more types of powder and granular starch (hereinafter, the above various deodorants may be collectively referred to as deodorants) are added and mixed. The features of the present invention include powder, granular petroleum wax, powder, granular vegetable wax, powder, granular animal wax, powder, granular low molecular weight polyolefin resin, powder, granular atactic polypropylene resin, Powder, granular graphite, wood flour, rice husk powder, granular pulverized product, grain powder, granular pulverized product, powder A deodorizing agent made of one or more types of granular starch is coated on the surface to form a waterproof coating and then added to water glass molding sand or cement molding sand. The newly developed molding sand with the addition of a molding sand disintegrant has improved sand fluidity, reduces the work of pounding and hardening the molding sand, and makes molding easier.
In addition, since the water-absorbing substance is waterproofed, it does not adsorb the moisture required for the binder, so the usable life of the kneaded sand is long, and the surface stability of the mold at room temperature is also good, making it easier to use water glass-based molding sand. In some cases, the amount of water glass added can be smaller than that of conventional water glass molding sand. The mold sand disintegrating agent, which is scattered between the sand grains, is heated by high-temperature water during pouring and melts and dissolves before the mold sand expands, and its fluidity is extremely good, allowing it to flow out and disperse widely in the gaps between the sand grains. However, especially in the case of water glass-based molding sand, before the hardened water glass is softened under high temperature and pressure, a carbonized film is formed on the surface of the sand grains and the binder to prevent the binder from sticking. Small cavities are formed in the area where this mold sand disintegrator dissolves, making the mold porous and acting as a buffer for the sand that expands with the temperature of the water and the compressive force generated during the solidification process of the casting. Absorbs and prevents mold destruction.
The greater the amount of residual heat after casting, the wider the range of carbonization in which the mold sand disintegrator elutes, and the mold exhibits extremely remarkable collapsibility. The deodorant is dispersed and dotted between the sand grains, and when poured, it is heated with high-temperature water, and all substances other than graphite are carbonized. This carbide acts as a buffer material that absorbs the sand that expands with the temperature of the water and the compressive force generated during the solidification process of castings, and not only has an auxiliary effect on improving collapsibility, but also acts as a material for powder, granular wax, and powder. The unpleasant odor that occurs when granular low-molecular-weight polyolefin resins are burned is caused by the addition of deodorizing agents, which increases the melting point and causes the combustion temperature to shift to a higher temperature side, resulting in high-temperature combustion. This deodorizing effect plays an important role in improving the working environment. To explain the present invention in more detail, powder added as a deodorant, granular graphite, wood flour, rice husk powder, granular pulverized product, grain powder, granular pulverized product,
Powder, granular petroleum-based wax, powder, granular vegetable-based wax,
Powder, granular animal wax, powder, granular low molecular weight polyolefin resin, powder, granular atactic polypropylene resin, powder, granular one or more of so-called kettle residue resin-like substances of unknown chemical structure, 5 to 5 The amount is preferably within 100 parts by weight.This deodorant is waterproofed using a Henschel mixer.The Henschel mixer is equipped with a jacket for cooling water on the outer wall of the stirring section, and powder, granular wax, or powder,
When 100 parts by weight of one or more granular low molecular weight polyolefin resins and 5 to 100 parts by weight of one or more deodorants are simultaneously added and stirred, the mixture is mixed. The powder, granular wax, powder, granular low molecular weight polyolefin resin, etc. and the deodorant heat up to around 50℃ due to friction, and this heat causes the powder, granular wax, powder, granular low molecular weight polyolefin resin, etc. Molecular weight polyolefin resin and the like soften and adhere to the surface of the deodorant to form a waterproof coating. The deodorizer coated with a waterproof coating is fed into the cooling water jacket of the Henschel mixer and cooled while stirring, and the powder, granular wax, powder, granular low molecular weight polyolefin resin, etc. and the deodorant solidify. It is possible to obtain a mold sand disintegrating agent with good fluidity by preventing the deodorizing agent's waterproof coating from peeling off. This waterproof stirrer is not limited to Henschel mixers;
The powder, granular wax, powder, granular low molecular weight polyolefin resin, etc. will not be crushed or crushed, and the powder, granular wax, powder, granular low molecular weight polyolefin resin, etc. will not be crushed or crushed by frictional heat. Any type of stirrer may be used as long as it does not melt, and cooling may not require the use of cooling water. In this case, take out the mold sand disintegrator that has been waterproofed from the stirrer and leave it to disperse at room temperature, or
Cooling may be performed by gentle wind using a blower, or forced cooling may be performed using cold air. Deodorants can be used even if they are not waterproof. In this case, a mixture of powder, granular wax, powder, granular low molecular weight polyolefin resin, etc., and one or more deodorizers is added to the molding sand. Alternatively, one or more of powder, granular wax or powder, granular low-molecular-weight polyolefin resin, etc. and one or more of deodorants are simultaneously added to the molding sand and stirred. . Mold sand made by adding and kneading a mold sand disintegrant without waterproofing to a deodorizer is powder, granular wax or powder,
If the mixing ratio of one or more of the granular low molecular weight polyolefin resins, etc. and one or more of the deodorants is the same, molds using waterproofed deodorizers Although the deodorizing effect is inferior to that of sand disintegrants, and the usable life of the kneaded sand is shortened, if a continuous kneader is used to knead the molding sand, molds can be easily formed even if the usable time is short. Next, the disintegrating properties of the mold sand disintegrating agent of the present invention will be explained using examples. The sample used for this measurement was a JIS-specified 50φ x 50 length, and the measurements included a surface stability test, room temperature strength test, and residual strength test at each heating temperature.The results are shown in Table 1 and It is shown in Table 2. The composition of the mold sand disintegrant used here is: Mold sand disintegrator-1 A mixture of 100 parts by weight of powdered or granular petroleum wax and 45 parts by weight of powdered or granular furnace carbon. Mold sand disintegrant - 2 A mixture of 100 parts by weight of powdered or granular petroleum wax and 45 parts by weight of powdered or granular channel carbon. Mold sand disintegrant - 3 100 parts by weight of powdered or granular petroleum wax and 45 parts by weight of wood powder
Mixture with parts by weight. Mold sand disintegrator-4 A mixture of 100 parts by weight of powdered or granular petroleum-based wax and 45 parts by weight of rice husk powder or pulverized granules. Mold sand disintegrant - 5 A mixture of 100 parts by weight of powdered or granular petroleum-based wax and 45 parts by weight of rice flour or granular crushed material. Mold sand disintegrant - 6 A mixture of 100 parts by weight of powdered or granular petroleum wax and 45 parts by weight of powdered or granular starch. Mold sand disintegrant - 7 A mixture of 100 parts by weight of powdered or granular vegetable wax (carnauba wax) and 45 parts by weight of wood flour. Mold sand disintegrant - 8 Powder, granular vegetable wax (cotton wax) 100
A mixture of parts by weight and 45 parts by weight of wood flour. Mold sand disintegrant - 9 Powder, granular animal wax (Mitsuwa wax)
A mixture of 100 parts by weight and 45 parts by weight of wood flour. Mold sand disintegrant - 10 Powder, granular animal wax (wool wax)
A mixture of 100 parts by weight and 45 parts by weight of wood flour. Mold sand disintegrant - 11 A mixture of 100 parts by weight of powder or granular low molecular weight polyolefin resin and 45 parts by weight of wood flour. Mold sand disintegrant - 12 Powder, granular atactic polypropylene resin
A mixture of 100 parts by weight and 45 parts by weight of wood flour. Mold sand disintegrant - 13 Powder, granular, so-called pot residue resinous material with unknown chemical structure
A mixture of 100 parts by weight and 45 parts by weight of wood flour. Example 1 Self-hardening mold sand Silica sand (No. 6 for foundries) 100 parts by weight Molding sand disintegrant-1 1.2 parts by weight Water glass (molar ratio 2.5, 42B- _e ) 6 parts by weight Hardening agent (Dical powder) 2 parts by weight Example 2 Self-hardening mold sand Silica sand (No. 6 for foundries) 100 parts by weight Molding sand disintegrant-2 1.2 parts by weight Water glass (molar ratio 2.5, 42B- _e ) 6 parts by weight Hardening agent (Dical powder) 2 parts by weight Example 3 Self-hardening mold sand Silica sand (No. 6 for foundries) 100 parts by weight Molding sand disintegrant-3 1.2 parts by weight Water glass (molar ratio 2.5, 42B- _e ) 6 parts by weight Hardening agent (Dical powder) 2 parts by weight Example 4 Self-hardening mold sand Silica sand (No. 6 for foundries) 100 parts by weight Molding sand disintegrant-4 1.2 parts by weight Water glass (molar ratio 2.5, 42B- _e ) 6 parts by weight Hardening agent (Dical powder) 2 parts by weight Example 5 Self-hardening mold sand Silica sand (No. 6 for foundries) 100 parts by weight Molding sand disintegrant-5 1.2 parts by weight Water glass (molar ratio 2.5, 42B- _e ) 6 parts by weight Hardening agent (Dical powder) 2 parts by weight Example 6 Self-hardening mold sand Silica sand (No. 6 for foundries) 100 parts by weight Molding sand disintegrant-6 1.2 parts by weight Water glass (molar ratio 2.5, 42B- _e ) 6 parts by weight Hardening agent (Dical powder) 2 parts by weight Example 7 Self-hardening mold sand Silica sand (No. 6 for foundries) 100 parts by weight Molding sand disintegrant-7 1.2 parts by weight Water glass (molar ratio 2.5, 42- _e ) 6 parts by weight Hardening agent (Dical powder) 2 parts by weight Example 8 Self-hardening mold sand Silica sand (No. 6 for foundries) 100 parts by weight Molding sand disintegrant-8 1.2 parts by weight Water glass (molar ratio 2.5, 42- _e ) 6 parts by weight Hardening agent (Dical powder) 2 parts by weight Example 9 Self-hardening mold sand Silica sand (No. 6 for foundries) 100 parts by weight Molding sand disintegrant-9 1.2 parts by weight Water glass (molar ratio 2.5, 42- _e ) 6 parts by weight Hardening agent (Dical powder) 2 parts by weight Example 10 Self-hardening mold sand Silica sand (No. 6 for foundries) 100 parts by weight Molding sand disintegrant-10 1.2 parts by weight Water glass (molar ratio 2.5, 42- _e ) 6 parts by weight Hardening agent (Dical powder) 2 parts by weight Example 11 Self-hardening mold sand Silica sand (No. 6 for foundries) 100 parts by weight Molding sand disintegrant-11 1.2 parts by weight Water glass (molar ratio 2.5, 42- _e ) 6 parts by weight Hardening agent (Dical powder) 2 parts by weight Example 12 Self-hardening mold sand Silica sand (No. 6 for foundries) 100 parts by weight Molding sand disintegrant-12 1.2 parts by weight Water glass (molar ratio 2.5, 42- _e ) 6 parts by weight Hardening agent (Dical powder) 2 parts by weight Example 13 Self-hardening mold sand Silica sand (No. 6 for foundries) 100 parts by weight Molding sand disintegrant-13 1.2 parts by weight Water glass (molar ratio 2.5, 42- _e ) 6 parts by weight Hardening agent (Dical powder) 2 parts by weight In Examples 1 to 13, samples were collected, molded, left at room temperature, and measured after curing was completed. Example 14 CO ₂ gas molding sand Silica sand (No. 6 for foundries) 100 parts by weight Molding sand disintegrant-1 1.2 parts by weight Water glass (molar ratio 2.3, 50- _e ) 6 parts by weight Example 15 CO ₂ gas molding sand Silica sand (No. 6 for foundries) 100 parts by weight Molding sand disintegrator-3 1.2 parts by weight Water glass (molar ratio 2.3, 50- _e ) 6 parts by weight Example 16 CO ₂ gas molding sand Silica sand (No. 6 for foundries) 100 parts by weight Mold sand disintegrant - 8 1.2 parts by weight Water glass (molar ratio 2.3, 50 - _e ) 6 parts by weight Example 17 CO ₂ gas mold sand silica sand (No. 6 for foundries) 100 parts by weight Mold sand disintegrant - 10 1.2 parts by weight Glass (molar ratio 2.3, 50- _e ) 6 parts by weight Example 18 CO ₂ gas mold sand silica sand (No. 6 for foundries) 100 parts by weight Molding sand disintegrant - 11 1.2 parts by weight Water glass (molar ratio 2.3, 50- _e ) 6 parts by weight In Examples 14 to 18, samples were collected, molded, and then cured by passing CO ₂ gas through them for 30 seconds before measurement. Example 19 Cement molding sand silica sand (No. 6 for foundry use) 100 parts by weight Molding sand disintegrant-1 1.2 parts by weight Portland cement 8 parts by weight Water 8 parts by weight Example 20 Cement molding sand silica sand (No. 6 for foundry use) 100 Parts by weight Mold sand disintegrant - 3 1.2 parts by weight Portland cement 8 parts by weight Water 8 parts by weight Example 21 Cement mold sand silica sand (No. 6 for foundries) 100 parts by weight Mold sand disintegrant - 8 1.2 parts by weight Portland cement 8 parts by weight Part water 8 parts by weight Example 22 Cement molding sand silica sand (No. 6 for casting) 100 parts by weight Molding sand disintegrant - 10 1.2 parts by weight Portland cement 8 parts by weight Water 8 parts by weight Example 23 Cement molding sand silica sand (for casting 6) 100 parts by weight Mold sand disintegrant - 11 1.2 parts by weight Portland cement 8 parts by weight Water 8 parts by weight In Examples 19 to 23, samples were collected, molded, left at room temperature, and measured after hardening was completed. I did it.

[Table] To measure the surface stability, place the sample in a foundry sand sieve (rotap type) and vibrate it on the sieve for 2 minutes.
The ratio of the sample weight before measurement to the sample weight after measurement was expressed in %.

[Table] The compositions of conventional self-hardening molding sand and cement molding sand in Table 2 are as follows. Self-hardening molding sand Silica sand (No. 6 for foundry use) 100 parts by weight Water glass (molar ratio 2.5, 42B- _e ) 6 parts by weight Hardening agent (Dical powder) 2 parts by weight Cement molding sand Silica sand (No. 6 for foundry use) 100 Parts by weight Portland cement 8 parts by weight Peach coke powder 1.5 parts by weight Water 8 parts by weight Compared to the residual strength of conventional self-hardening molding sand and cement molding sand, Example 1 of the present invention at 1100°C
The residual strength of ~23 is extremely low and excellent. In addition, these molding sand disintegrants 1 to 13 are not limited to silica sand, but can also include olivine sand and zircon sand, and the water glass used as a binder is a low molar ratio water glass for CO ₂ gas molding sand. to high molar ratio water glass, and binder cements ranging from ordinary Portland cement to ultra-early strength Portland cement can be used. As described above, the mold sand disintegrant of the present invention improves the disintegrability of the mold simply by adding it to mold sand.
When using this mold sand disintegrant, the sand kneading equipment and mold forming method are completely unchanged from the conventional water glass molding method or cement molding method, and the management and handling of the sand is easy. By using this new mold sand disintegrant, there is no hygroscopicity, easy molding, good strength at room temperature and surface stability after storage, and there are no defects in castings caused by gases generated by combustion of combustible materials. Castings cast with molding sand exhibit extremely remarkable collapsibility during sand removal work, the work progresses quickly, productivity is improved, and the degree of worker fatigue is minimal. Some of the deodorants added to the molding sand disintegrating agent of the present invention are treated as industrial waste, and together with the improvement of their recycling, the resource saving effect is also significant. By providing an extremely excellent mold sand disintegrator, the foundry industry can bring great benefits.

Claims (1)

[Claims] 1. 5 to 100 parts by weight of one or more of powder, granular graphite, wood flour, rice husk powder, pulverized granules, grain powder, pulverized granules, flour, and granular starch, into powder, granular petroleum-based wax, powder, granular vegetable-based wax,
A mold sand disintegrator obtained by surface treatment with 100 parts by weight of one or more of powdered or granular animal wax, powdered or granular low molecular weight polyolefin resin, or powdered or granular atactic polypropylene resin.