JP2013103158A - Method for removing urethane from metal-urethane composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for removing urethane from a metal-urethane composite material with high work efficiency and at a shorter work time.SOLUTION: With regard to a composite material (metal-urethane composite material) having a core bar and a coating layer containing a urethane resin formed on the surface of the core bar, the method for removing the coating layer containing the urethane resin (method for removing urethane) from the composite material is characterized by involving a first step in which the metal-urethane composite material is left in water or oil heated to a predetermined temperature for a predetermined time, and a second step which is carried out after the first step and in which the metal-urethane composite material is removed from the water or oil and the coating layer is removed within a predetermined time.

Description

  The present invention relates to a method of removing a coating layer containing urethane resin from a composite material (referred to as a metal / urethane composite material) having a cored bar and a coating layer containing a urethane resin formed on the surface of the cored bar (urethane removal) Method). Specifically, it relates to a method of removing urethane from metal / urethane composites used in automobile parts such as steering wheels and electrical equipment. In other words, recovery of metal cores and recycling of metal / urethane composites. This is a usage method.

Magnesium alloys have the highest strength per unit weight among practical metals and can be recycled. In recent years, magnesium alloys have been widely used for automotive parts and electrical equipment. Especially, it is used suitably as components for motor vehicles in which both strength and lightness are required. Recycling of automobile parts is obligatory, and it is also important that energy consumption during recycling is low and CO ₂ emissions are low. However, since magnesium alloys are not sufficiently recyclable compared to iron or the like, there is a need for a recycling method that has a short working time, low cost, and good recycling efficiency. There is also a need for a recycling method that reduces the environmental burden caused by the discharge of waste liquid.

  When recycling metals used in automobile parts, etc., urethane resins are often combined with urethane resins or painted with urethane resin paints. It is necessary to separate it from In the case of iron, since the melting point is 1000 ° C. or higher, the urethane resin is decomposed prior to the melting of iron during melting. However, the melting point of the magnesium alloy is about 600 ° C., which is lower than that of iron and the like, and is easily oxidized. Therefore, there is a limit to the high temperature, and it is difficult to separate the urethane resin by decomposition during melting. Moreover, since molten magnesium has a small specific gravity, it is not easy to separate the urethane resin and its decomposition products due to the difference in specific gravity.

  For this reason, when recycling a metal / urethane composite such as a magnesium alloy, it is usually melted after removing the coated urethane resin or the urethane resin coating. Play to ingot. Patent Document 1 discloses a magnesium alloy coating film in which a part of a coating film is removed from a magnesium alloy material coated with a urethane resin paint by a cutter knife or wet blasting, and then the coating film is further removed with an alkaline stripping solution. A removal method is described. Further, it is also described that the magnesium alloy after removal of the coating film is melted and regenerated into an ingot.

JP 2004-99993 A

  However, in the case of blasting, it is difficult to remove the urethane resin adhering to the fine irregularities, and a large amount of dust is generated. The dust containing magnesium is easy to burn and has a safety problem. In addition, when using an alkaline solution such as an alkaline stripping solution, the waste solution must be treated by treating the alkaline solution in which a part of the urethane resin is dissolved through multiple stages of processing, which requires extremely high processing costs. Had the problem of becoming.

  Accordingly, an object of the present invention is to provide a method for removing urethane from a metal / urethane composite material, which has good working efficiency and can shorten the working time.

  The urethane removal method of the present invention is a method in which a metal / urethane composite material is placed in hot water or hot oil at a predetermined temperature for a predetermined time (= after swelling and softening the urethane resin), and within a predetermined time (the urethane resin is constant) It is characterized in that the coating layer is removed in a swollen or softened state.

  According to the present invention, the metal / urethane composite material is swelled and softened in water (including steam) or oil heated to a predetermined temperature for a predetermined time, so that the urethane resin is not dissolved (peeled). The bonding force with the surface can be greatly reduced. Therefore, water or water is impregnated in a state where the urethane resin is swollen and softened by impregnation with hot water or hot oil at a predetermined temperature (= a state in which the bonding strength and mechanical strength between the urethane resin and the core metal surface are greatly reduced). It is taken out from the oil and the coating layer is removed within a predetermined time. By doing so, the coating layer can be removed from the metal / urethane composite material in a short time with high work efficiency. As described above, it is possible to provide a urethane removal method that has high work efficiency from the metal / urethane composite material and can shorten the work time as compared with the prior art (Patent Document 1).

It is process drawing in the urethane removal method from a metal and urethane composite material. 2A is a view showing the appearance of the core bar after the coating layer is removed from the steering wheel of the metal / urethane composite material within a predetermined time (while the urethane resin in the coating layer is swollen and softened). Is a drawing of the front side of the cored bar, and FIG. 2B is a drawing of the back side of the cored bar of FIG. 2A.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may be different from the actual ratios.

  The method for removing urethane from a metal / urethane composite material according to the present invention removes a coating layer containing urethane resin from a metal / urethane composite material having a metal core and a coating layer containing urethane resin formed on the surface of the metal core. The method includes the following steps.

  First, it includes a first step in which the metal / urethane composite is left in water or oil heated to a predetermined temperature for a predetermined time to swell and soften the urethane resin in the coating layer.

  Further, after the first step, the metal / urethane composite material is taken out of water or oil, and the coating layer is removed within a predetermined time (while the urethane resin in the coating layer is in a certain swelling and softened state). It includes two steps.

  Hereinafter, as an embodiment (first embodiment) of the urethane removal method of the present invention, an example in which a steering wheel is used for a metal / urethane composite material will be mainly described. However, the present invention is not limited to these. Not a thing.

  Although the use of Mg alloys is progressing in automobile parts, among them, many Mg alloys are used for the core metal of the steering wheel. A steering wheel usually has a structure in which a core metal made of a magnesium alloy is covered with a coating layer containing a urethane resin formed by foaming a crosslinked polyurethane resin composition. The coating layer can be formed by RIM molding (Reaction Injection Molding) or the like. Such a coating layer often contains carbon black or the like in order to improve the strength. Since such a urethane resin has high adhesion to the core metal (Mg alloy), it is difficult to peel from the core metal (Mg alloy). Further, since the urethane resin is crosslinked, it cannot be dissolved in an organic solvent, and it is difficult to dissolve and remove the organic resin using an organic solvent. In addition, the cored bar may be provided with a recess (V-shaped groove around the entire steering) to prevent peeling (especially prevention of rotation of the coating layer during gripping), or the spoke may be integrally formed. Often, this makes peeling more difficult. Furthermore, since urethane resin is a foam containing air, its thermal conductivity is low, and heat decomposition by firing hardly transfers heat to the inside, so only the surface is carbonized first, making it difficult for internal decomposition to proceed. It was difficult to completely remove the film. With regard to this phenomenon, a strong bond (physical bond) due to the so-called anchor effect can be considered, but in the case of a urethane resin, the viscosity of the resin composition (solution) was high, and it was considered not to be an anchor effect. For this reason, the functional group (OH group, etc.) and the urethane resin (isocyanate group, etc.) on the surface of the core metal (Mg alloy) have been strongly chemically bonded by a so-called chemical reaction. It seemed difficult to do. On the other hand, as a result of earnestly examining the above problems without being caught by conventional technical common sense (conventional concept), the present inventors have found that the core metal (Mg alloy) surface and the urethane resin are not chemically bonded, both It is known that they are bonded by the intermolecular van der Waals force. From this knowledge, even if the alkali stripping solution penetrates to the interface between the core metal and the urethane resin, and the core metal and urethane resin at the interface are not dissolved and peeled off, the urethane resin is swollen and softened to increase the bond distance between molecules. And found that van der Waals power can be reduced. Furthermore, it has been found that when the removal operation is performed in a state where the urethane resin is swollen and softened, the mechanical strength of the urethane resin is also lowered, and therefore the coating layer can be removed very easily. On the other hand, in the process where the urethane resin is cooled and contracted and cured from the swollen and softened state to the original state, the bond distance between the molecules is shortened, the van der Waals force is increased, and the mechanical strength is also increased. For this reason, it has also been found that the removal of the coating layer becomes very difficult (the working efficiency is drastically reduced) when it is no longer swollen and softened.

  Hereinafter, each component of this embodiment will be described in detail.

(1) Metal / urethane composite material The metal / urethane composite material that can be used in the present embodiment is not particularly limited, and any conventionally known metal / urethane composite material can be applied. For example, in the case of moving parts such as vehicles, examples of the metal / urethane composite material include a steering wheel, a seat seat frame, a shift knob, a door knob, a saddle, and a handle, but are not limited thereto. Absent. Further, in the case of electrical equipment and the like, examples of the metal / urethane composite material include, but are not limited to, a handle / knob of game equipment, a handle of health equipment, and the like.

  Examples of the moving body such as a vehicle include a moving body such as a bulldozer, an excavator, a truck crane, and a forklift among general construction machines in addition to a vehicle, an aircraft, and a ship. However, it is not limited to these. Vehicles include automobiles that use gasoline or bioethanol as fuel, electric vehicles that use secondary batteries or fuel cells, and four-wheeled vehicles such as hybrid vehicles (passenger cars, trucks, buses, etc.); motorcycles, bicycles; railways Vehicles (trains, hybrid trains, locomotives, etc.) are examples. However, it is not limited to these. Examples of the electric device include an amusement vehicle. However, it is not limited to these.

(A) Core metal The core metal material is not particularly limited as long as it is a metal material (including an alloy) satisfying characteristics (for example, mechanical strength, specific gravity) and economy (cost) according to the purpose of use. It is not a thing. The metal materials (including alloys) include magnesium and its alloys, aluminum and its alloys, iron and its alloys (including stainless steel), titanium and its alloys, cobalt and its alloys, nickel and its alloys, copper and its Examples include alloys, but are not limited thereto. Preferably, it is a metal (alloy) that has a lower melting point than a metal in which the urethane resin is decomposed prior to melting of iron by melting and is difficult to separate the urethane resin by decomposition at the time of melting. This is because these metals are difficult to melt and the application of the urethane removal method of the present invention is extremely effective. From this viewpoint, a magnesium alloy or an aluminum alloy is preferable. These metals (alloys) are excellent in that they have higher mechanical strength, can be reduced in weight with a low specific gravity.

  The magnesium alloy of the core metal only needs to have magnesium as a main component, and the content of the magnesium element is usually 50% by mass or more, and preferably 80% by mass or more. Examples of magnesium alloys include Mg-Al alloys, Mg-Al-Zn alloys, Mg-Al-Mn alloys, Mg-Zn-Zr alloys, Mg-rare earth elements alloys, Mg-Zn-rare earth elements alloys. Etc. Usually, an Mg-Al alloy is used for the core for the steering wheel. The aluminum alloy of the core metal only needs to have aluminum as a main component, and the content of aluminum element is usually 50% by mass or more, and preferably 80% by mass or more. Aluminum alloys include Al-Mg alloys, Al-Mg-Zn alloys, Al-Mg-Mn alloys, Al-Zn-Zr alloys, Al-rare earth elements alloys, Al-Zn-rare earth elements alloys. Etc. Usually, an Al—Mg alloy is used for the steering wheel core metal.

  The form (shape) of the core bar is not particularly limited. For example, in the case of moving parts such as a vehicle, a part having a specific shape for each part such as a form (shape) of a core bar used for a steering wheel, a seat seat frame, a shift knob, a door knob, or the like can be a target. For example, taking a steering wheel as an example, the shape of the steering wheel is usually composed of a rim portion that a passenger grips, a spoke portion, and a boss portion that is attached to the vehicle body. The mandrel of the steering wheel made of magnesium alloy may be one in which the rim, spoke and boss are integrally formed of, for example, Mg alloy or Al alloy, or Mg alloy or Al may be formed only on a part of the steering wheel. A cored bar made of an alloy or the like may be used. The rim portion is usually circular. Further, in order to improve the adhesion between the coating layer and the cored bar and prevent displacement, the rim part of the cored bar is often formed with a groove (concave) on the surface.

(B) Coating layer As a coating layer containing a urethane resin (including a foamed urethane resin) formed on the surface of the core metal, the urethane of the present embodiment can be used as long as the urethane resin is directly formed on the core metal surface. A removal method is applicable.

  For example, taking a steering wheel as an example, the whole of the core metal of the steering wheel may be covered with a coating layer, or only a part thereof may be covered with a film. Usually, the entire rim portion is covered with a coating layer.

Moreover, as a structure of the coating layer containing a urethane resin, (i) the coating layer of the single layer structure which consists of urethane resins;
(Ii) A multi-layer coating layer comprising: a urethane resin formed on the surface of the core metal; and a wood-tone resin film or a wood-like thin plate-like wood formed for the purpose of imparting design properties to the urethane resin surface ;
(Iii) A multilayer comprising: a urethane resin formed on the core metal surface; and a leather material bonded or stitched to the urethane resin surface for the purpose of imparting design properties, a high-class feeling of leather products, a feeling of touch, etc. And the like. However, the present embodiment is not limited to these. The urethane removing method of the present embodiment has a urethane resin formed on the surface of the core metal, and can particularly effectively act on a coating layer having high adhesion with the core metal.

  Here, the urethane resin is not particularly limited, and conventionally known resins can be used. Further, the urethane resin may be one having a urethane resin as a main component (50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more). As needed, additives, such as antioxidant, a light stabilizer, a foaming agent, or a filler, may be contained individually by 1 type or in combination of 2 or more types. The urethane resin is usually a urethane bond formed by condensation of a compound (for example, polyisocyanate and polyol) having an OH (hydric acid) group such as an NCO (isocyanate) group and an alcohol group. It is a molecular compound. A crosslinked structure can be introduced by using a polyisocyanate or polyol having a valence of 3 or more. Taking the cover layer of the steering wheel as an example, as the urethane resin, foamed urethane resins (various foamed urethane resins having different foaming ratios) are suitably used. The urethane foam resin is made into a resin by mixing a foaming agent (water, fluorocarbon, etc.), a foam stabilizer (silicone oil), a catalyst (amine compound, etc.), a colorant, etc. with a polyol and polyisocyanate as main components. However, it is foamed (foam). Among these, those in which bubbles communicate and are soft and have a restoring property are also called soft urethane homes. On the other hand, the rigid urethane foam comprises a polyisocyanate having two or more NCO (isocyanate) groups and a polyol having two or more OH (hydric acid) groups, a catalyst (amine compound, etc.), a blowing agent (water, fluorocarbon, etc.), It is a uniform plastic foam obtained by mixing together with a foam stabilizer (silicone oil), etc., and performing foaming reaction and resinification reaction simultaneously. It looks like a collection of small bubbles, and each of these small hard bubbles is an independent bubble that contains a gas that is difficult to transfer heat. For this reason, the rigid urethane foam maintains an excellent heat insulation performance unlike any other over the long term. As described above, since the urethane resin is a foam, a soft hand can be obtained and the material can be reduced in weight. Moreover, the heat insulation is also high. RIM molding is suitably used as a method for forming a coating layer made of a urethane resin foam. This is a method in which two or more types of monomers are mixed and injected into a mold together with a catalyst, a crosslinking agent, a foaming agent, and the like to cause a polymerization reaction and foam at the same time to obtain a foam molded product. Since the raw material enters the mold in the state of a monomer having a low viscosity, the injection pressure may be low, and it is suitably used for the production of a steering wheel coating layer. As a urethane resin molding material suitable for such RIM molding, for example, a crosslinked polyurethane composition described in JP-A-2006-199719 can be used, but is not limited thereto.

  The thickness of the coating layer is not particularly limited. That is, in this embodiment, even if the thickness of the coating layer is different, by leaving the metal / urethane composite material in water (including steam) or oil heated to a predetermined temperature for a predetermined time, What is necessary is just to swell and soften this urethane resin. Therefore, depending on the thickness of the coating layer, especially the thickness of the urethane resin in the coating layer, the urethane resin will be in a sufficiently swollen and softened state (= a state in which the bonding force with the core metal surface is greatly reduced). In addition, the heating temperature and heating time in water (including steam) or oil may be appropriately adjusted. Taking a steering wheel as an example, the thickness of the coating layer covering the cored bar is not particularly limited, but is usually about 1 to 30 mm. Urethane resin has good adhesion to a core metal (Mg alloy, Al alloy, etc.), and is suitably used as a coating layer for a steering wheel.

  The specific gravity of the urethane resin in the coating layer is not particularly limited, and a specific gravity according to the purpose of use is used. For example, taking a coating layer of a steering wheel as an example, the specific gravity of urethane resin is generally in the range of 0.3 to 0.7. In this embodiment, as shown in Table 1 of Examples described later, the specific gravity of the urethane resin is preferably in the range of 0.4 to 0.6, more preferably in the range of 0.4 to 0.5. In contrast, it is particularly excellent in that the urethane removal work time can be greatly shortened. However, the present embodiment is not limited to these ranges. In other words, in the examples, a comparative study is performed without performing the pretreatment process. However, for those in which the specific gravity of the urethane resin is outside the above-described preferred range, the pretreatment process described below is performed, and then This is because the work of removing the coating layer in the second step can be greatly shortened. In addition, the specific gravity of a urethane resin can be measured using a specific gravity measuring device.

(2) About each process of the urethane removal method Next, it demonstrates per each process of the urethane removal method from an above-described metal and urethane composite material. FIG. 1 is a process diagram in a method for removing urethane from a metal / urethane composite material. As shown in FIG. 1, the first step 13 and the second step 15 are essential as the steps in the method of removing urethane from the metal / urethane composite material, and further, the urethane resin is swollen and softened in the first step 13. When oil is used, it is desirable to perform the third step 17 after the second step 15. Furthermore, you may perform the pre-processing process 11 before the 1st process 13 as needed. In particular, when the coating layer has a multilayer structure including a urethane resin, it is desirable to perform the pretreatment step 11. Hereinafter, it demonstrates in order of a process including an arbitrary process.

(A) Pretreatment step 11
As the pretreatment step 11, any one of the following steps (i) and (ii) is performed before the first step 13. In particular, when the coating layer has a multilayer structure including a urethane resin, it is desirable to perform the pretreatment step 11. As the multilayer structure, for example, a multilayer structure in which a coating layer is further provided with an outer layer such as a resin coating, a thin plate-like wood, and a leather material on the surface (outside) of a urethane resin (inner layer) formed on the surface of the core metal. However, it is not limited to these.

  (I) A step of forming mechanical damage on the coating layer is performed. Specifically, a step of cutting the coating layer with a depth reaching the surface of the metal core with a blade (for example, a cutter knife) or the like is performed. At this time, when the cored bar is recycled, it is desirable that the surface of the cored bar is not damaged. For example, as shown in FIG. 1, when the steering wheel 21 is taken as an example, an outer layer resin film, a thin plate-like wood or leather material constituting the coating layer 23 with a blade (for example, a cutter knife; not shown), Further, a process of making a notch 25 having a depth reaching the surface of the core metal through the inner layer urethane resin is performed. Thereby, in the 1st process 13 of the following process, penetration of water or oil heated to predetermined temperature to urethane resin is promoted, and time shortening can be aimed at. Furthermore, water or oil heated to a predetermined temperature can penetrate into the urethane resin in a short time, swell and soften, and the bond distance between the molecules between the core surface and the urethane resin can be increased in a short time. It is excellent in that the virus power can be reduced. From this point of view, is it possible to form a plurality of incisions 25 with a knife (for example, a cutter knife) at regular intervals throughout the coating layer 23 so that heated water or oil can penetrate into the entire coating layer (see FIG. 1)? Alternatively, it is desirable to form the entire periphery of the coating layer, but the present invention is not limited thereto.

  In the present embodiment, the coating layer is not limited to the case where the urethane resin is a multilayer structure, and even when the coating layer is made of a urethane resin, the step of forming mechanical damage may be performed in the same manner as in the above (i). Good. Thereby, an above-described effect can be produced.

  (Ii) A step of cutting the stitched portion of the outer layer of the covering layer having the stitched portion is performed. For example, taking a steering wheel as an example, a step of cutting the stitched portion (sewn portion, sewing thread along the seam) of the leather material of the outer layer of the covering layer having a stitched (sewn) portion with a blade (for example, scissors) I do. As a result, in the first step of the next step, water or oil heated to a predetermined temperature can permeate the urethane resin in a short time, swell and soften, and molecules between the core material surface and the urethane resin. It is excellent in that the bond distance between them is wide and van der Waals force can be reduced. In this case, water or oil can permeate through the gap between the stitched portions (seams) of the leather material and can penetrate into the urethane resin of the inner layer, but the leather material tends to shrink when wet with liquid (water or oil). And prevents the urethane resin in the inner layer from swelling. Therefore, cutting the stitched portions (sewn portions, sewing threads along the seams) of the leather material of the outer layer can be an effective means so as not to prevent the swelling of the urethane resin of the inner layer. In addition, when removing the covering layer in the second step, the outer layer can be quickly removed by cutting the stitched portion (sewn portion, sewing thread along the seam) of the outer layer leather material. The work efficiency (time reduction) can be improved.

(B) First step 13
In the first step 13, the metal / urethane composite material is placed in water or oil heated to a predetermined temperature for a predetermined time (= impregnating the coating layer with hot water or hot oil to swell and soften the urethane resin in the coating layer) Process). This allows the urethane resin in the coating layer to swell and soften by allowing the metal / urethane composite material to stand in water (including steam) or oil heated to a predetermined temperature for a predetermined time, thereby dissolving the urethane resin. The bonding force with the metal surface can be greatly reduced without (peeling). As a result, the urethane resin in the coating layer is swollen and softened by impregnating with hot water or hot oil at a predetermined temperature (= bonding strength with the core metal surface is greatly reduced, and mechanical strength is also greatly reduced. State). In this embodiment, hot water or hot oil is sufficiently applied to the urethane resin in the coating layer only by placing it in water or oil heated to a predetermined temperature as described above for a predetermined time without performing the above pretreatment step. The urethane resin in the coating layer can be swollen and softened by impregnation. However, by performing the pretreatment step 11, hot water or hot oil is quickly impregnated in the urethane resin from the pretreated portion, and can be swollen and softened in a shorter time, and the time required for the first step is reduced. It is excellent in that it can be shortened.

The temperature of the water heated to the predetermined temperature in the first step is not particularly limited as long as it is in a temperature range where the above-described effects can be achieved, but is preferably in the range of 40 to 100 ° C, more preferably. Is in the range of 60-100 ° C. If the temperature of water is 40 degreeC or more, it is excellent in the point which can fully swell and soften the urethane resin in a coating layer. On the other hand, if the temperature of water is 100 ° C. or lower, it is not necessary to use an expensive pressure-resistant device and the pressure is high, which is economically excellent. Moreover, it is excellent also for the global environment in that the amount of energy such as electricity and gas used for heating in the process and the amount of CO ₂ emitted when the energy is generated can be suppressed. In addition, if the water temperature is within the above range, the urethane resin will not be decomposed and dissolved in the water from the metal / urethane composite material. By simply replenishing the water, the water can be used over and over again.

  Note that the heated water here includes steam (water vapor). This is because even if steam is used, the urethane resin of the coating layer can be impregnated with hot water, and the above-described operational effects can be sufficiently exhibited.

  Use pure water, ion-exchanged water, tap water (tap water), well water (ground water), rain water (reserved water), industrial water, fresh water from seawater, sewage-treated water, etc. Can do. In addition, various amounts of various additives (for example, surfactants, antioxidants, ultraviolet absorbers, lubricants, etc.) may be mixed in the water as long as the effects of the present invention are not hindered. . In the case of treating industrial waste (hereinafter also referred to as industrial waste) after removing the urethane resin impregnated with water in the next step, it is desirable to use inexpensive industrial water or the like from the viewpoint of economy. In the case where the urethane resin impregnated with water is removed in the next step and then dried and regenerated (recycled) using, for example, a regeneration technique, it is desirable to use clean water with relatively low cost and high purity. The regeneration technique is not particularly limited, and a conventionally known regeneration technique can be used. For example, the production of a cushion material containing parenchyma cells described in JP 2010-208306 A proposed by the present applicant. Recycling can be achieved using a method or the like.

Next, the temperature of the oil heated to the predetermined temperature in the first step is not particularly limited as long as it is in a temperature range where the above-described effects can be achieved, but is preferably in the range of 40 to 200 ° C. More preferably, it is the range of 80-200 degreeC. If the temperature of oil is 40 degreeC or more, it is excellent in the point which can fully swell and soften the urethane resin in a coating layer. On the other hand, if the temperature of the oil is 200 ° C. or lower, the oil to be used can be widely used without being limited. Moreover, it is excellent also for the global environment in that the amount of energy such as electricity and gas used for heating in the process and the amount of CO ₂ emitted when the energy is generated can be suppressed. Also, if the temperature of the oil is within the above range, the urethane resin will not be decomposed and dissolved from the metal / urethane composite material into the oil. By simply replenishing the oil, the oil can be used over and over again.

  Moreover, any of mineral oil, vegetable oil, and animal oil may be sufficient as the oil to be used, and these waste oils may be used (refer the Example mentioned later). In addition, various amounts of various additives (for example, surfactants, antioxidants, ultraviolet absorbers, lubricants, etc.) may be mixed in the oil as long as the effects of the present invention are not impaired. . The mineral oil is not particularly limited, and a conventionally known mineral oil can be used. For example, petroleum (naphtha, gasoline, light oil, kerosene, heavy oil), mineral oil (mineral oil), paraffin, baby oil, liquid paraffin, ceresin, mineral wax, petroleum wax, silicon oil, dredging oil, shale oil, creosode oil However, it is not limited to these. Examples of the vegetable oil include castor oil (castor oil), paulownia oil, nanjo oil oil (jatropha oil), bird mill oil, linseed oil (flux seed oil, linseed oil), shortening, salad oil, white squeezed oil, corn oil, large Bean oil, sesame oil (sesame oil), rapeseed oil (canola oil), safflower oil (safflower oil), sunflower oil, rice bran oil, coconut oil, coconut oil, palm oil, palm kernel oil, coconut oil (copra oil), cottonseed oil, hemp seed oil (Hemp oil), camellia oil, poppy oil (poppy seed oil), mustard oil, wheat germ oil, evening primrose oil, shiso oil, camellia oil, camellia oil, apricot kernel oil (apricot kernel oil), akebi oil (akebi seed oil) , Mountain tea flower oil (tea plum oil), tea oil, walnut oil, birch oil, daifu oil, soybean oil, nutmeg oil, olive oil, peanut oil, almond oil, Boca do oil, hazelnut oil, grape seed oil, laurel oil (laurel oil), macadamia nut oil, argan oil, pumpkin seed oil, pecan nut oil, pistachio oil, jojoba oil, cacao butter, borage oil (borage seed oil), shea butter, Babas oil, Baobao oil, melon seed oil, mango butter, salva butter, cocle butter, meadow foam oil, coffee bean oil, marula nut oil, broccoli seed oil, peach kernel oil, cherry kernel oil, cranberry seed oil, pomegranate seed oil, cucumber nut oil , Neem oil (Margossa oil), Kiwi fruit seed oil, Rosehip oil, Seabaxon (Sea buckthorn seed oil), Mongongo oil, Oil bitumen oil, Chin Oil, honey 陀油, Japan wax, candelilla wax, carnauba wax, essential oils (essential oils) and the like, shall by no means be limited to these. Animal oils include, for example, lard, het (beef tallow), bone fat, bone oil, fish oil, chicken oil, duck oil, chick bird oil, cocoon oil, coconut oil, lanolin (wool grease), Schmalz, butter, emu oil, su Oil (sea bream oil), ghee, catfish oil (main ingredients are horse oil), whale oil, dolphin oil, mink oil, squalane, egg yolk oil, liver oil, cocoon oil, cow leg oil, beeswax, etc. It is not limited. These oils (including waste oil) may be used alone or in combination of two or more. When industrial waste treatment is performed after the urethane resin impregnated with oil is removed in the next step, it is desirable to use inexpensive waste oil from the viewpoint of economy. For example, taking a steering wheel as an example, it is desirable to use waste oil such as hydraulic oil, gear oil, cutting oil, etc. of a vehicle such as an automobile generated during the production or disassembly of a vehicle such as an automobile as in the case of a steering wheel. This is because the waste oil can be reused as it is without incurring transportation and recovery costs. After removing the urethane resin impregnated with oil in the next step, it is desirable to use mineral oil or vegetable oil when degreasing, drying, and regenerating (recycling) using a regeneration technique, for example. The regeneration technique is not particularly limited, and a conventionally known regeneration technique can be used. For example, the production of a cushion material containing parenchyma cells described in JP 2010-208306 A proposed by the present applicant. Recycling can be achieved using a method or the like.

The time in which the metal / urethane composite material in the first step is placed in water heated to a predetermined temperature (including in a steam (vapor) atmosphere) is particularly limited as long as it is in a temperature range where the above-described effects can be achieved. Although it is not a thing, Preferably it is the range for 5 minutes or more, More preferably, it is the range for 10 minutes or more. If the time of placing in water heated to the above-mentioned predetermined temperature is 5 minutes or more, it is excellent in that the urethane resin in the coating layer can be sufficiently swollen and softened. On the other hand, the upper limit value of the time in the water heated to the above-mentioned predetermined temperature is not particularly limited, but if it is approximately 60 minutes or less, the energy such as electricity and gas used for the heating in the process. It is also excellent for the global environment in that the amount and the amount of CO ₂ emitted when producing the energy can be suppressed. However, in the present invention, the above range (particularly the upper limit value) is not limited at all, and the present invention can be applied as long as it is within the range in which the effects of the present invention can be effectively expressed.

The time for which the metal / urethane composite material in the first step is placed in the oil heated to a predetermined temperature is not particularly limited as long as it is in a temperature range in which the above-mentioned effects can be achieved, but preferably 5 minutes. It is the above range, More preferably, it is the range for 10 minutes or more. If the time of placing in the oil heated to the above-mentioned predetermined temperature is 5 minutes or more, it is excellent in that the urethane resin in the coating layer can be sufficiently swollen and softened. On the other hand, the upper limit value of the time in the oil heated to the above-mentioned predetermined temperature is not particularly limited. However, if it is approximately 60 minutes or less, such as electricity or gas used for heating in the process. It is also excellent for the global environment in that the amount of energy and the amount of CO ₂ emitted when producing the energy can be suppressed. Further, in the case of oil, it is oxidized and deteriorated when left in a heated state for a long time, but in this embodiment, such a state, that is, oil that has become waste oil can be used sufficiently. There is no particular limitation. That is, from the viewpoint of suppressing oxidation, it may be performed in an inert gas atmosphere such as N ₂ gas, He gas, Ar gas, etc., but from the viewpoint of economy (cost reduction), it is performed in the atmosphere. Particularly desirable. However, in the present invention, the above range (particularly the upper limit value) is not limited at all, and the present invention can be applied as long as it is within the range in which the effects of the present invention can be effectively expressed.

  As a method of placing the metal / urethane composite in water or oil heated to a predetermined temperature, (1) a method of immersing in a water tank or oil tank containing water or oil heated to a predetermined temperature, (2) steam ( A method of placing it in a heated steam atmosphere.

  In the method (1), as shown in FIG. 1, while the water 27 or the oil 27 ′ heated to a predetermined temperature is immersed in the water tank 29 or the oil tank 29 ′, the water tank 29 or the oil tank 29 is immersed. 'Inner water (hot water) 27 or oil (hot oil) 27' may be stirred. However, by heating to the above-mentioned predetermined temperature, water (hot water) 27 or oil (hot oil) 27 ′ in the water tank 29 or oil tank 29 ′ is vigorously convected (heat flow) by heating (= similar to stirring) In particular, it is not necessary to perform stirring. As shown in FIG. 1, heating may be performed using a heater (coil heater) 29. Or you may provide the jacket (not shown) which can let a heat medium pass around the water tank 27 or the oil tank 27 '. Further, a heater may be wound directly around the water tank 27 or the oil tank 27 ′ (not shown), or a heating source such as a heater (coil heater) may be installed inside the water tank 27 or the oil tank 27 ′ ( It is not particularly limited.

  In the case of the above method (2), steam may be sprayed onto the metal / urethane composite material, or it may be simply steamed with steam. For example, using an industrial steamer that uses the same principle as a cooking steamer, steaming steam with steam from the bottom of a steamer containing metal / urethane composite material swells urethane resin. It may be softened.

  In any of the above methods (1) and (2), as shown in step 13 of FIG. 1, a plurality of metal / urethane composite materials (steering wheel 21) can be used together (a number that can be processed in the next step 15). From the viewpoint of production efficiency, it is desirable to swell and soften with a certain interval. At this time, the metal / urethane composites are in close contact with each other, so that the water or oil penetration does not become uneven depending on the location. It is good to make it go around.

  In addition, the swelling rate of the urethane resin in the coating layer at the end of the first step (in other words, in a swollen and softened state) is not particularly limited. Preferably, when water is used, it is 0.5% or more, particularly 1.5% or more, and when oil is used, it is 0.5% or more, particularly 1.5% or more. If the swelling ratio is 0.5% or more when water is used and 0.5% or more when oil is used, the urethane resin in the coating layer is swollen and softened = the urethane resin in the coating layer The bonding strength with the core metal surface and the mechanical strength are greatly reduced. Therefore, in the next step (second step), by removing the coating layer within a predetermined time (that is, while it is in a swollen and softened state), the metal / urethane composite material can be efficiently removed in a short time. The coating layer can be removed. The upper limit value of the swelling ratio of the urethane resin in the coating layer at the end of the first step (in other words, in a swollen and softened state) is not particularly limited. That is, swelling may be performed up to the maximum swelling rate of each urethane resin (that is, a saturated state filled with water or oil that can be impregnated inside the urethane resin under a predetermined heating temperature condition).

  The swelling ratio of the urethane resin is calculated by the following formula (1) or (2) (in the examples and comparative examples described later, both are easy to measure in a short time, and the following formula (1) with little measurement error. Was calculated using

(C) Second step 15
In the second step 15, after the first step 13, the step of taking out the metal / urethane composite from water or oil and removing the coating layer within a predetermined time is performed. As a result, the metal / urethane composite material is taken out from water or oil, and the urethane resin in the covering layer is impregnated with hot water or hot oil at a predetermined temperature to swell and soften (= the binding force with the surface of the metal core) The coating layer can be removed while the mechanical strength is greatly reduced. As a result, the coating layer can be removed from the metal / urethane composite material in a short time with high work efficiency. That is, the metal / urethane composite material is excellent in that the work efficiency is good and the work time can be greatly shortened as compared with the prior art (for example, Patent Document 1).

  The time for removing the coating layer within the predetermined time in the second step is preferably within 40 minutes, preferably within 30 minutes, more preferably within 20 minutes when water (including steam) is used in the first step. In addition, when the oil is used in the first step, the time for removing the coating layer within the predetermined time in the second step is preferably within 40 minutes, preferably within 30 minutes, and more preferably within 25 minutes. When water (including steam) is used in the first step, if the time for removing the coating layer within the predetermined time of the second step is within 40 minutes, the swollen and softened state = bonding force with the core metal surface In the state where the mechanical strength is greatly reduced, it is excellent in that the coating layer can be easily removed from the metal / urethane composite material with work efficiency. Similarly, when oil is used in the first step, if the time for removing the coating layer within the predetermined time of the second step is within 40 minutes, the state is swollen and softened = bonding force with the core metal surface and the machine It is excellent in that the coating layer can be easily removed from the metal / urethane composite material with good work efficiency while the mechanical strength is greatly reduced.

  The swelling ratio of the urethane resin in the coating layer (in the swollen and softened state) at the end of the second step is 0.5% or more, preferably 1.5% when water is used in the first step. The above is desirable, and when oil is used in the first step, it is desirably 0.5% or more, preferably 1.5% or more. If the swelling ratio is 0.5% or more when water is used in the first step and 0.5% or more when oil is used, the swollen and softened state = bonding force with the core metal surface and mechanical It is excellent in that the coating layer can be removed from the metal / urethane composite material in a short time with high work efficiency while the strength is greatly reduced. The upper limit value of the swelling ratio of the urethane resin in the coating layer in the swollen and softened state is not particularly limited. That is, swelling may be performed up to the maximum swelling rate of each urethane resin (that is, a saturated state filled with water or oil that can be impregnated inside the urethane resin under a predetermined heating temperature condition). In addition, the swelling rate of a urethane resin shall be computed by said Formula (1) or (2).

  In this step 15, the method for removing the coating layer from the metal / urethane composite material is not particularly limited, and a conventionally known method can be used, and an appropriate method according to the shape of the metal / urethane composite material. A simple jig may be used so that the work can be performed more efficiently. Furthermore, such a jig may be used to automate the removal operation to further increase the work efficiency.

  Taking the steering wheel 21 as an example, for example, when the work is performed manually, the entire covering layer 23 ′ of the rim portion 22 ′ of the tearing wheel 21 ′ is within a predetermined time (in a so-called swollen and softened state). A notch is made around the core with a plastic spatula or the like (see FIG. 1). Then, it may be peeled up and down along the cut portion 25a. As a result, the coating layer (not shown) in the concave portion (V-shaped groove) can be removed cleanly.

  In addition, when the notch is formed in the whole circumference | surroundings of the coating layer 23 of the rim | limb part 22 by the pre-processing process 11, it is only necessary to peel up and down along the said notch part 25, and shortening of working time can be aimed at. However, in the pretreatment step 11, the urethane resin (coating layer 23) is not swollen or softened, and the same cutting operation can be performed in a shorter time when the same cutting operation is performed. Therefore, when the coating layer is not a multilayer structure but a single layer structure made of urethane resin, it is better in terms of work efficiency to omit the pretreatment step 11.

  Further, depending on the temperature and time of the first step, and also the specific gravity (foaming ratio and degree of crosslinking) of the urethane resin, the coating layer may remain in the concave portion (V-shaped groove) of the rim portion. Even in such a case, the V-shaped resin guide can be easily peeled off by inserting it along the concave portion (V-shaped groove) of the rim portion.

  Further, the covering layer 23 'of the spoke portion 24' and the boss portion 26 'of the steering wheel 21' is also the same as the covering layer 23 'of the rim portion 22' within a predetermined time (while being swollen and softened). Cut with a resin spatula to reach the cored bar 33. Then, it may be peeled off along the cut portion 25a into which the cut has been made. In addition, when the notch 25 is formed in the coating layer 23 of the spoke part 24 and the boss | hub part 26 by the pre-processing process 11, it is only necessary to peel along the said notch part 25, and shortening of working time can be aimed at.

  In addition, it is desirable to automate part or all of the manual work using a jig or the like that can simultaneously cut and peel the coating layer of a metal / urethane composite material (for example, a steering wheel). For example, as an example of a jig for automation, a jig having a roller, a rotary motor, etc. so that the rim portion of the steering wheel in a swollen and softened state can be rotated concentrically and the rotation speed can be adjusted. Can be mentioned. The jig has a cleaving tool (for example, a resin spatula, etc.) on the periphery of the rim that can be freely adjusted in the cutting depth in the center direction (depth direction) of the rim that is swollen and softened. Is provided. Further, the jig includes a peeling tool (for example, a pointed resin guide, etc .; the depth of which can be adjusted in the center direction) that can be peeled up and down along the cut portion. It is provided on the outside of the peripheral portion behind the slitting tool (backward with respect to the rotation direction). The peeling tool (pointed resin guide) may be provided at a plurality of locations so that it can be peeled off in the vertical direction stepwise. In this case, the resin guide provided on the rear side may be larger, and in the resin guide provided on the rear side, the mounting position is provided at two locations on the upper side and the lower side of the widened cut portion. May be. Further, a resin guide suitable for the V-shaped groove may be further provided. When processing (swelling or softening) a plurality of metal / urethane composite materials (for example, steering wheel) at a time in the first step, prepare the number of jigs corresponding to the number of treatments. It is desirable that parallel processing can be performed within a predetermined time (= short time). However, the present embodiment is not limited to such a jig.

  In order to remove the coating layer within a predetermined time (while being swollen and softened) using such a jig, the rim portion of the steering wheel installed in the jig (so-called swollen and softened) Are rotated concentrically at a constant speed. A plastic spatula is pressed against the rotating rim (swelled and softened) so that the notch is made deeper and deepened until it reaches the core metal surface. The resin spatula is fixed to. Next, the resin guide is inserted to a depth that reaches the surface of the core metal along the cut portion inserted in the rotating rim portion, and is peeled up and down while being expanded in the vertical direction. By doing so, the coating layer can be removed within a predetermined time (while being swollen and softened). When the coating layer of the V-shaped groove remains, a dedicated resin guide suitable for the V-shaped groove is inserted along the V-shaped groove of the rotating rim portion to the depth reaching the core metal surface at the bottom of the groove. By taking out the coating layer from the mold groove, the coating layer of the V-shaped groove can also be removed within a predetermined time (while being swollen and softened). In addition, about spoke parts and boss | hub parts other than a rim | limb part, it should sever and cut up and down along a notch part using a resin spatula etc. by hand so that it may reach a metal core. By doing so, the spoke portion and the boss portion other than the rim portion can also be removed within a predetermined time (while being swollen and softened).

  As shown in step 15 of FIG. 1, the coating layer 23 ′ is removed from the steering wheel 21 ′ of the metal / urethane composite material within a predetermined time (while being swollen and softened) in the coating layer 23 ′. By doing so, it can be divided into a core metal 33 and a coating layer 23 '. Of these, the coating layer 23 ′ may be recovered at this point and recycled or industrial waste. On the other hand, regarding the metal core 33, when water (hot water) 27 is used, it is recovered at this time and may be recycled as a metal core for steering wheel, an ingot or the like. When oil (hot oil) 27 ′ is used, the third step 17 shown below is performed, collected, and recycled as a steering wheel core bar, ingot, or the like.

  FIG. 2 shows a core bar after removing the coating layer from the steering wheel of the metal / urethane composite material within a predetermined time (while it is swollen and softened) in the coating layer (step 15 in FIG. 1). It is drawing which represented the external appearance of the metal core 33). 2A is a drawing of the front side of the cored bar, and FIG. 2B is a drawing of the back side of the cored bar of FIG. 2A. In this embodiment, since the coating layer is removed while the urethane resin in the coating layer is swollen and softened, as shown in FIGS. The coating layer can be reliably removed in a short time.

(D) Third step 17
In the third step 17, when oil is used in the first step 13, the second step 15 is followed by a step of degreasing and washing the core after removing the coating layer. As a result, oil remaining on the surface of the metal core can be washed away, and the degreased metal core can be heated and melted and reused as an ingot, or a coating layer can be formed and recycled as a metal / urethane composite material. .

The degreasing solvent that can be used for oil degreasing and washing is not particularly limited, and conventionally known degreasing solvents can be used. For example, gasoline, naphtha, petroleum, carbon tetrachloride, acetone, alcohol, ethanol, trichloroethylene, perchloroethylene, methylene chloride, methylpyrrolidone, and the like can be used. Commercially available detergents may also be used, for example, detergent (chemical name) Techniclean 200 EF (supplier; B-P Japan Co., Ltd., ingredients; diphosphate tetrapotassium salt diphosphate and tetrapotassium, silicic acid. A cleaning solution in which (H ₂ SiO ₃ ), alkoxylated long-chain alcohol, 2-phenoxytanol, 2- (2 butoxyethoxy) ethanol) is mixed with water in an appropriate ratio can be used, but is not limited thereto. It is not something. These may be used alone or in combination of two or more. The drawing showing the core after removing the coating layer from the steering wheel of the metal / urethane composite material and degreasing is omitted because it has no difference in appearance from FIGS. 2A and 2B (see FIGS. 2A and 2B). ).

  As the degreasing cleaning method in this step 17, it is desirable to carry out the following procedures (1) to (3), but the procedure is not limited to these procedures. (1) Wipe the surface of the mandrel with a cloth material such as a cloth (cloth used for wiping off machine oil or wiping off dirt and impurities). This is excellent in that most of the oil on the surface of the metal core can be efficiently removed. The cloth material is not particularly limited as long as it is a cloth material, a paper material, an oil-absorbing soft resin sheet, etc., which are excellent in oil absorption, and conventionally known materials can be used. (2) The core metal wiped off with the cloth material is degreased and washed. Specifically, the core metal may be immersed in the above-described degreasing solvent (which may be stirred) and degreased and washed. In this case, it is desirable to degrease and clean the core metal by immersing it in an ultrasonic cleaner (oscillation frequency 28 kHz) filled with a degreasing solvent. This is because oil remaining in a narrow gap of the core metal can be sufficiently washed. Further, as shown in FIG. 1, a degreasing solvent 37 is sprayed or sprayed (sprayed or sprayed) on a metal core 31a to which oil adheres, from a faucet 35 leading to a degreasing solvent storage tank (not shown). There is no particular limitation such as washing, and a conventionally known method can be used. The former (especially degreasing with an ultrasonic cleaner) is desirable from the viewpoint of the working environment, temperature control of the degreasing solvent, and recycling of the degreasing solvent after use. (3) Wash the degreased cored bar with water and dry. This is excellent in that a clean cored bar can be quickly obtained without leaving a degreasing solvent on the cored bar. For washing with water, as in the method of degreasing and washing in (2) above, after immersing the core metal in water (which may be stirred) and washing with water, using a suitable dryer (hot air dryer, etc.) It may be dried. In this case, it is desirable to wash the core metal by immersing it in an ultrasonic cleaner (oscillation frequency 28 KHz) filled with water. This is because the degreasing solvent remaining in the narrow gap of the core metal can be sufficiently washed. In addition, after pouring water from a tap water faucet to the metal core to which the degreasing solvent adheres, or spraying (spraying, spraying) and washing with water, it is dried using an appropriate dryer (hot air dryer, etc.). There is no particular limitation such as may be used, and a conventionally known method can be used. The drying conditions are not particularly limited as long as the water can be quickly evaporated. For example, a hot air drying of about 40 to 200 ° C. is performed even though rough water is blown off with an air jet or the like. It may be dried by vacuum drying, heat drying with a heater or the like. Among the degreasing and cleaning methods in this step 17, the above-described degreasing and washing, water washing and drying procedures of (2) and (3) as well as the first step 13 are performed by appropriately combining a plurality of core bars 31a. It is desirable from the standpoint of production efficiency that the degreasing, washing and drying be performed with a certain interval. At this time, the core metal 31a to which the oil adheres is in close contact with each other, so that the cleaning and drying effects do not become uneven depending on the location, and the degreasing solvent 37 and the cleaning water are spaced apart from each other at appropriate intervals. In addition, it is recommended that hot air at the time of drying spreads to every corner. In this step 17, (1) wiping with a cloth material, (2) degreasing, (3) washing and drying the cored bar 31 (see FIG. 1) is recovered, and the steering wheel cored bar or ingot And the like. Even when water is used in the first step 13, after the second step 15, the above-described (3) washing with water (especially washing with an ultrasonic cleaner) and drying the core after removing the coating layer are performed. May be.

  The time required for removing the urethane (the time required for all the steps described above) is within 60 minutes, preferably within 50 minutes, more preferably within 40 minutes, particularly preferably when water is used in the first step. It is within 30 minutes, or when oil is used in the first step, it is within 80 minutes, preferably within 70 minutes, more preferably within 60 minutes. If the time required for removing urethane (the time required for all the steps described above) is within 60 minutes when water is used in the first step, all steps from the pretreatment step (optional) to the second step are performed. be able to. In particular, in a state where the urethane resin swells and softens within a specified time = the state in which the bonding strength with the core metal surface and the mechanical strength are greatly reduced, the coating layer can be easily and efficiently worked from the metal / urethane composite material. It is excellent in that it can be removed. If the time required for removing urethane (the time required for all the steps described above) is within 80 minutes when oil is used in the first step, all steps from the pretreatment step (optional) to the third step are performed. be able to. In particular, in a state where the urethane resin swells and softens within a specified time = the state in which the bonding strength with the core metal surface and the mechanical strength are greatly reduced, the coating layer can be easily and efficiently worked from the metal / urethane composite material. It is excellent in that oil that adheres to the metal core can be removed sufficiently.

(Second Embodiment)
Next, the method for regenerating a metal / urethane composite material according to the present invention uses a cored bar obtained by the method of removing urethane from the metal / urethane composite described above, and a coating layer containing a urethane resin on the surface of the cored bar. It is formed and recycled as a metal / urethane composite material.

  Hereinafter, as an embodiment (second embodiment) of a method for regenerating a metal / urethane composite material according to the present invention, an example using a steering wheel will be mainly described, but the present invention is not limited to these. Not.

As a metal core obtained by the above-described method for removing urethane from the metal / urethane composite material, using a metal core for a steering wheel, a coating layer containing urethane resin is formed on the surface of the metal core, and is reproduced as a steering wheel. Is a preferred embodiment of this embodiment. Normally, damaged products produced during the manufacture of steering wheels are used as industrial waste because they are judged to be inefficient because the urethane resin and cored bar in the grip part are in close contact with each other and it takes time to peel off. This is the current situation. However, a metal such as aluminum, magnesium, or iron is used for the steering wheel core metal, and effective utilization is desired from the viewpoint of raw materials. In this embodiment, the coating layer can be removed from the steering wheel of the used product or the damaged product, and it can be reused as it is without being melted by heating and ingot. It is excellent in that it can be effectively used from recycled parts. In addition, according to the present embodiment, compared with the case where it is heated and melted and regenerated as a metal ingot, the amount of CO ₂ emission is small and the energy efficiency is excellent. Are better.

  In addition, with respect to the method of forming a coating layer containing a urethane resin on the surface of the core metal using the core metal obtained by the urethane removal method from the metal / urethane composite described above, there is no limitation. It can be manufactured in the same manner as a normal product (metal / urethane composite material) using an existing metal / urethane composite material (for example, steering wheel) manufacturing facility. In particular, in the case of a damaged product generated at the time of manufacture, it is also excellent in that it is not necessary to newly install a separate manufacturing facility or add an additional manufacturing facility. However, in the case of used products collected from scrapped vehicles, etc., if the manufacturer is different, or if the model has already been changed and the shape of the steering wheel has been changed, the following third embodiment will be used. What is necessary is just to reproduce | regenerate as a metal in dot.

(Third embodiment)
Next, the core metal regeneration method of the present invention is characterized in that the core metal obtained by the urethane removal method from the above-mentioned metal / urethane composite material is heated and melted to regenerate as an ingot. .

  Hereinafter, as an embodiment (third embodiment) of the method for reclaiming a core metal of the present invention, an explanation will be made focusing on an example using a core metal of a steering wheel, but the present invention is not limited to these. Not.

  It is a preferred embodiment of the present embodiment that the steering wheel core bar is regenerated as a metal ingot such as an Mg alloy as the core bar obtained by the urethane removing method from the metal / urethane composite. Normally, damaged products produced during the manufacture of steering wheels are used as industrial waste because they are judged to be inefficient because the urethane resin and cored bar in the grip part are in close contact with each other and it takes time to peel off. This is the current situation. However, a metal such as aluminum, magnesium, or iron is used for the steering wheel core metal, and effective utilization is desired from the viewpoint of raw materials. In this embodiment, by the method for removing urethane from the metal / urethane composite material, as shown in FIGS. 2A and 2B, by reliably removing the coating layer from the mandrel for the steering wheel, The generation of impurities that affect the quality is greatly suppressed. Therefore, it is possible to recycle used goods collected from scrapped vehicles, etc., and scrap metal steering wheel cores that are produced during production into high-quality metal alloys such as Mg alloys, which are effective in terms of raw materials. It can be said that it can be utilized.

  The temperature at which the core metal is heated and melted is appropriately determined according to the difference in the type (melting temperature) of the core metal material. In manufacturing the metal ingot, a conventionally known manufacturing technique can be used as appropriate. For example, in order to remove impurities in the molten metal (alloy) bath, an appropriate additive may be added, or an appropriate gas may be blown to remove impurities by sedimentation or floating, etc. There is no particular limitation. Furthermore, when producing a metal ingot, for example, when the core metal material is an Mg-Al alloy, when the metal ingot is used for a different purpose of use, in order to adapt to the purpose, in the molten metal (alloy) bath, A metal (for example, Zn or Mn) may be added. Thereby, you may manufacture the ingot of a different composition, such as a Mg-Al-Zn type alloy and a Mg-Al-Mn type alloy, adapted to a different use purpose.

  The recycled metal ingots such as Mg alloy and the like can be used for manufacturing core bars such as a steering wheel, a seat seat frame, a shift knob, and a door knob. In this case, the metal ingot such as Mg alloy obtained by smelting from a normal mineral may be used by blending the metal ingot such as Mg alloy regenerated in this embodiment in an appropriate ratio. Or you may utilize for the use completely different from the conventional metal core, for example, you may use for the housing | casing of a personal computer, the housing | casing of a video and a camera, the component adjustment agent of an aluminum alloy, etc.

  In each of the following examples and comparative examples, an experiment was performed using 110 samples (steering wheels). For each measurement value, an average value of these 110 samples was used. For example, the urethane specific gravity of the urethane resin coating layer of the steering wheel has very little variation, and the sample of Example 1 is in the range of about 0.38 to 0.42. The sample in Example 2 is approximately in the range of about 0.48 to 5.2. The sample of Example 3 is approximately within the range of 0.5.3-5.7. The same applies to other examples and comparative examples. However, regarding the composition of the alloy of the core metal, the distribution range of the sample is shown instead of the average value of the sample.

(1) Hot water heating experiment (85-95 ° C)
Example 1 (Mg alloy core + urethane specific gravity 0.4 urethane resin coating layer steering wheel → hot water immersed in 10 minutes, coating layer removal operation)
(A) First step (a-1) As an experimental water tank (container), 40 liters of water was prepared in a cooking zundo (inner diameter 430 mm, depth 455 mm), and water was heated. Tap water was used as water. The temperature of water was measured using a K thermocouple (the same applies to the following examples).

    (A-2) When the temperature of water reached 85 ° C., the steering wheel was introduced (immersed), and after the addition (immersion), the temperature was adjusted so that the water was within the range of 85 to 95 ° C. The steering wheel has a core metal made of an Mg-AL-Mn alloy (Mg: AL: Mn (mass ratio) = remainder: 5-6: 1 or less) and a specific gravity formed on the surface of the core metal by RIM molding. A steering wheel comprising a 0.4 urethane foam coating layer was used. The specific gravity of the urethane foam resin in the coating layer was measured using a specific gravity measuring instrument (the same applies to the following examples).

    (A-3) Ten minutes after the steering wheel was introduced, the first step was completed. After completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2.6%. The swelling ratio of the urethane resin was calculated by the above formula (1) (the same applies to the following examples).

(B) Second Step After the completion of the first step, the steering wheel is immediately pulled up from the water tank, and while the urethane resin is swollen and softened, the rim portion and spoke of the steering wheel are manually operated using a resin spatula. The coating layer (urethane resin) of the part and the boss part was removed (the core metal and the resin layer were separated and recovered), and the second step was completed (see FIGS. 2A and 2B). The time required for removing the urethane resin was 5 minutes. The swelling ratio of the urethane resin at the end of the second step was 2.6%. The collected metal core can be recycled for steering wheel manufacturing or alloy ingot manufacturing. The recovered coating layer (urethane resin) can be used for industrial waste treatment or recycling.

Example 2 (Mg alloy cored bar + urethane resin coating layer having a specific gravity of 0.5, steering wheel → after 10 minutes of hot water immersion, coating layer removal work)
Instead of the steering wheel of Example 1, a core metal made of an Mg—AL—Mn alloy (Mg: AL: Mn (mass ratio) = remainder: 5-6: 1 or less) and the surface of the core metal by RIM molding A hot water heating experiment was conducted in the same manner as in Example 1 except that a steering wheel composed of a formed urethane resin coating layer having a specific gravity of 0.5 was used.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 1.8%. The time required for the operation of removing the urethane resin in the second step was 6 minutes.

Example 3 (Mg alloy cored bar + urethane resin coating layer having a specific gravity of 0.55, steering wheel → after 10 minutes of hot water immersion, coating layer removal operation)
Instead of the steering wheel of Example 1, a core metal made of an Mg—AL—Mn alloy (Mg: AL: Mn (mass ratio) = remainder: 5-6: 1 or less) and the surface of the core metal by RIM molding A hot water heating experiment was conducted in the same manner as in Example 1 except that a steering wheel made of a foamed urethane resin coating layer having a specific gravity of 0.55 was used.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 1.8%. The time required for the operation of removing the urethane resin in the second step was 18 minutes.

Example 4 (Al alloy core + steering wheel of urethane resin coating layer having a specific gravity of 0.4 → after removing the coating layer after immersion in hot water for 10 minutes)
Instead of the steering wheel of Example 1, a cored bar made of an Al-Mg-Mn alloy (Al: Mg: Mn (mass ratio) = balance: 2.5-4: 0.4-0.6), A hot water heating experiment was conducted in the same manner as in Example 1 except that a steering wheel made of a foamed urethane resin coating layer having a specific gravity of 0.4 formed on the core metal surface by RIM molding was used.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2.6%. The time required for the operation of removing the urethane resin in the second step was 5 minutes.

Example 5 (Al alloy core + urethane resin coating layer having a specific gravity of 0.5, steering wheel → immersing the coating layer after immersion in hot water for 10 minutes)
Instead of the steering wheel of Example 1, a cored bar made of an Al-Mg-Mn alloy (Al: Mg: Mn (mass ratio) = balance: 2.5-4: 0.4-0.6), A hot water heating experiment was conducted in the same manner as in Example 1 except that a steering wheel composed of a foamed urethane resin coating layer having a specific gravity of 0.5 formed on the core metal surface by RIM molding was used.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 1.8%. The time required for the operation of removing the urethane resin in the second step was 6 minutes.

Example 6 (Al alloy cored bar + urethane resin coating layer having a specific gravity of 0.55, steering wheel → hot water 10 minutes immersion, coating layer removal operation)
Instead of the steering wheel of Example 1, a cored bar made of an Al-Mg-Mn alloy (Al: Mg: Mn (mass ratio) = balance: 2.5-4: 0.4-0.6), A hot water heating experiment was conducted in the same manner as in Example 1 except that a steering wheel composed of a foamed urethane resin coating layer having a specific gravity of 0.5 formed on the core metal surface by RIM molding was used.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 1.8%. The time required for the operation of removing the urethane resin in the second step was 18 minutes.

(2) Medium temperature vegetable oil heating experiment (120-140 ° C)
Example 7 (Mg alloy cored bar + urethane resin coating layer with specific gravity 0.4 Steering wheel → After immersion for 15 minutes in medium temperature vegetable oil, coating layer removal operation → cored bar degreasing cleaning)
(A) First step (a-1) As an experimental oil tank (container), 40 liters of vegetable oil was prepared in a cooking zundo (inner diameter 430 mm, depth 455 mm), and the vegetable oil was heated. . Waste oil such as salad oil was used as the vegetable oil. The temperature of the vegetable oil was measured using a K thermocouple (the same applies to the following examples).

    (A-2) When the temperature of the vegetable oil reached 120 ° C., the steering wheel was introduced (immersed), and after the addition (immersion), the temperature of the vegetable oil was adjusted to be within the range of 120 to 140 ° C. The steering wheel has a core metal made of an Mg-AL-Mn alloy (Mg: AL: Mn (mass ratio) = remainder: 5-6: 1 or less) and a specific gravity of 0 formed on the surface of the core metal by RIM molding. A steering wheel comprising a coating layer made of foamed urethane resin (4) was used.

    (A-3) The first step was completed 15 minutes after the steering wheel was introduced. After completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2.7%.

(B) Second Step After the completion of the first step, the steering wheel is immediately pulled up from the oil tank, and while the urethane resin is swollen and softened, the rim portion and spoke of the steering wheel are manually operated using a resin spatula. The coating layer (urethane resin) of the part and the boss part was removed (the core metal and the resin layer were separated, and the coating layer was recovered in this step), and the second step was completed. The time required for removing the urethane resin was 4 minutes. The recovered coating layer (urethane resin) can be used for industrial waste treatment or recycling.

(C) Third step After the second step, the core after removing the coating layer is degreased and washed (collecting the core) in the following steps (1) to (3), and the third step is completed. (See FIGS. 2A and 2B). That is, (1) The surface (oil) of the metal core after removing the coating layer was wiped with a waste cloth. (2) Next, the core metal wiped with the waste was immersed in an ultrasonic cleaner filled with a degreasing solvent (oscillation frequency 28 KHz), and degreased and cleaned. (3) The degreased and washed cored bar was washed with water and dried with hot air. As the degreasing solvent, a cleaning liquid having a ratio of water: detergent (chemical name) Techniclean 200 EF) = 10: 1 (volume ratio) was used. The washing (drying) time in this step according to the above (1) to (3) was 15 minutes. The collected metal core can be recycled for steering wheel manufacturing or alloy ingot manufacturing. The degreasing solvent (cleaning liquid) used for the degreasing cleaning can also be used for industrial waste treatment or recycling after recovery.

Example 8 (Mg alloy cored bar + urethane resin coating layer having a specific gravity of 0.5) Steering wheel of medium temperature vegetable oil 15 minutes after immersion, coating layer removal operation → cored bar degreasing cleaning)
Instead of the steering wheel of Example 7, a cored bar made of an Mg-AL-Mn alloy (Mg: AL: Mn (mass ratio) = remainder: 5-6: 1 or less) and the surface of the cored bar by RIM molding A medium temperature oil heating experiment was conducted in the same manner as in Example 7 except that a steering wheel composed of a foamed urethane resin coating layer having a specific gravity of 0.5 was formed.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2.0%. The time required for the operation of removing the urethane resin in the second step was 5 minutes.

Example 9 (Mg alloy cored bar + urethane resin coating layer with a specific gravity of 0.55 Steering wheel-> medium temperature vegetable oil immersed for 15 minutes, then coating layer removal operation-> cored bar degreasing cleaning)
Instead of the steering wheel of Example 7, a cored bar made of an Mg-AL-Mn alloy (Mg: AL: Mn (mass ratio) = remainder: 5-6: 1 or less) and the surface of the cored bar by RIM molding A medium temperature oil heating experiment was conducted in the same manner as in Example 7 except that a steering wheel made of a foamed urethane resin coating layer having a specific gravity of 0.55 was used.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2.1%. The time required for the urethane resin removal operation in the second step was 22 minutes.

Example 10 (Al alloy cored bar + steel wheel with urethane resin coating layer having a specific gravity of 0.4 → After soaking in medium temperature vegetable oil for 15 minutes, coating layer removal work → core metal degreasing and cleaning)
Instead of the steering wheel of Example 7, a cored bar made of an Al—Mg—Mn alloy (Al: Mg: Mn (mass ratio) = remainder: 2.5 to 4: 0.4 to 0.6); A medium temperature oil heating experiment was conducted in the same manner as in Example 7 except that a steering wheel composed of a foamed urethane resin coating layer having a specific gravity of 0.4 formed on the core metal surface by RIM molding was used.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2.7%. The time required for the operation of removing the urethane resin in the second step was 4 minutes.

Example 11 (Al alloy cored bar + steering wheel of urethane resin coating layer having a specific gravity of 0.5 → medium temperature vegetable oil immersed for 15 minutes, coating layer removal work → cored bar degreasing cleaning)
Instead of the steering wheel of Example 7, a cored bar made of an Al—Mg—Mn alloy (Al: Mg: Mn (mass ratio) = remainder: 2.5 to 4: 0.4 to 0.6); A medium temperature oil heating experiment was conducted in the same manner as in Example 7 except that a steering wheel comprising a foamed urethane resin coating layer having a specific gravity of 0.5 formed on the core metal surface by RIM molding was used.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2.0%. The time required for the operation of removing the urethane resin in the second step was 5 minutes.

Example 12 (Al alloy core metal + steering wheel of urethane resin coating layer having a specific gravity of 0.55 → immersion of medium temperature vegetable oil for 15 minutes, then removal of coating layer → core metal degreasing cleaning)
Instead of the steering wheel of Example 7, a cored bar made of an Al—Mg—Mn alloy (Al: Mg: Mn (mass ratio) = remainder: 2.5 to 4: 0.4 to 0.6); A medium temperature oil heating experiment was conducted in the same manner as in Example 7 except that a steering wheel made of a foamed urethane resin coating layer having a specific gravity of 0.55 formed on the core metal surface by RIM molding was used.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2.1%. The time required for the urethane resin removal operation in the second step was 22 minutes.

(3) High temperature vegetable oil heating experiment (180-200 ° C)
Example 13 (Mg alloy cored bar + steel wheel coated with urethane resin with specific gravity 0.4 → High temperature vegetable oil soaked for 20 minutes, then removed coating layer → core metal degreasing washed)
(A) First step (a-1) As an experimental oil tank (container), 40 liters of vegetable oil was prepared in a cooking zundo (inner diameter 430 mm, depth 455 mm), and the vegetable oil was heated. . The vegetable oil used was waste oil of salad oil.

    (A-2) When the temperature of the vegetable oil reached 180 ° C., the steering wheel was (immersed), and after the addition (immersion), the temperature was adjusted so that the vegetable oil was in the range of 180 to 200 ° C. The steering wheel is made of a Mg-AL-Mn alloy (Mg-AL-Mn alloy (Mg: AL: Mn (mass ratio) = balance: 5-6: 1 or less)) and a surface of the core metal. A steering wheel composed of a foamed urethane resin coating layer having a specific gravity of 0.4 formed by RIM molding was used.

    (A-3) The first step was completed 20 minutes after the steering wheel was introduced. After completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2.7%.

(B) Second Step After the completion of the first step, the steering wheel is immediately pulled up from the oil tank, and while the urethane resin is swollen and softened, the rim portion and spoke of the steering wheel are manually operated using a resin spatula. The coating layer (urethane resin) of the part and the boss part was removed (the core metal and the resin layer were separated, and the coating layer was recovered in this step), and the second step was completed. The time required for removing the urethane resin was 4 minutes. The recovered coating layer (urethane resin) can be used for industrial waste treatment or recycling.

(C) Third step After the second step, the core after removing the coating layer is degreased and washed (collecting the core) in the following steps (1) to (3), and the third step is completed. (See FIGS. 2A and 2B). That is, (1) The surface (oil) of the metal core after removing the coating layer was wiped with a waste cloth. (2) Next, the core metal wiped with the waste was immersed in an ultrasonic cleaner filled with a degreasing solvent (oscillation frequency 28 KHz), and degreased and cleaned. (3) The degreased and washed cored bar was washed with water and dried with hot air. As the degreasing solvent, a cleaning liquid having a ratio of water: detergent (chemical name) Techniclean 200 EF) = 10: 1 (volume ratio) was used. The washing (drying) time in this step according to the above (1) to (3) was 15 minutes. The collected metal core can be recycled for steering wheel manufacturing or alloy ingot manufacturing. The degreasing solvent (cleaning liquid) used for the degreasing cleaning can also be used for industrial waste treatment or recycling after recovery.

Example 14 (Mg alloy core + steering wheel of urethane resin coating layer with specific gravity of 0.5 → High temperature vegetable oil immersed for 20 minutes, then coating layer removal operation → core metal degreasing and cleaning)
Instead of the steering wheel of Example 13, a cored bar made of an Mg—AL—Mn alloy (Mg: AL: Mn (mass ratio) = remainder: 5-6: 1 or less) and the surface of the cored bar by RIM molding A high-temperature oil heating experiment was conducted in the same manner as in Example 13 except that a steering wheel composed of a foamed urethane resin coating layer having a specific gravity of 0.5 was formed.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2%. The time required for the operation of removing the urethane resin in the second step was 11 minutes.

Example 15 (Mg alloy core + steer wheel of urethane resin coating layer with specific gravity of 0.55 → high temperature vegetable oil immersed for 20 minutes, then coating layer removal operation → core metal degreasing and cleaning)
Instead of the steering wheel of Example 13, a cored bar made of an Mg—AL—Mn alloy (Mg: AL: Mn (mass ratio) = remainder: 5-6: 1 or less) and the surface of the cored bar by RIM molding A high-temperature oil heating experiment was conducted in the same manner as in Example 13 except that a steering wheel composed of a foamed urethane resin coating layer having a specific gravity of 0.55 was used.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2.1%. The time required for the operation of removing the urethane resin in the second step was 10 minutes.

Example 16 (Al alloy cored bar + steel wheel with urethane resin coating layer having a specific gravity of 0.4 → High temperature vegetable oil immersed for 20 minutes, then coating layer removal work → core metal degreasing and cleaning)
Instead of the steering wheel of Example 13, a cored bar made of an Al-Mg-Mn alloy (Al: Mg: Mn (mass ratio) = balance: 2.5-4: 0.4-0.6), A high-temperature oil heating experiment was conducted in the same manner as in Example 13 except that a steering wheel composed of a foamed urethane resin coating layer having a specific gravity of 0.4 formed on the core metal surface by RIM molding was used.

As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2.7%. The time required for the operation of removing the urethane resin in the second step was 4 minutes. Also,
Example 17 (Al alloy cored bar + steering wheel of urethane resin coating layer having specific gravity of 0.5 → high temperature vegetable oil immersed for 20 minutes, then coating layer removal work → cored bar degreasing)
Instead of the steering wheel of Example 13, a cored bar made of an Al-Mg-Mn alloy (Al: Mg: Mn (mass ratio) = balance: 2.5-4: 0.4-0.6), A high temperature oil heating experiment was conducted in the same manner as in Example 13 except that a steering wheel composed of a foamed urethane resin coating layer having a specific gravity of 0.5 formed on the core metal surface by RIM molding was used.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2.0%. The time required for the operation of removing the urethane resin in the second step was 11 minutes.

Example 18 (Al alloy core + steer wheel of urethane resin coating layer having a specific gravity of 0.55 → high temperature vegetable oil immersed for 20 minutes, then coating layer removal operation → core metal degreasing and cleaning)
Instead of the steering wheel of Example 13, a cored bar made of an Al-Mg-Mn alloy (Al: Mg: Mn (mass ratio) = balance: 2.5-4: 0.4-0.6), A high-temperature oil heating experiment was conducted in the same manner as in Example 13 except that a steering wheel composed of a foamed urethane resin coating layer having a specific gravity of 0.55 formed on the core metal surface by RIM molding was used.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2.1%. The time required for the operation of removing the urethane resin in the second step was 10 minutes.

(4) Warm water heating experiment (30 ° C)
Comparative Example 1 (Mg alloy cored bar + urethane resin coating layer having a specific gravity of 0.4, steering wheel → After 10 minutes of warm water immersion, the coating layer is removed)
Instead of the steering wheel of Example 1, a core metal made of an Mg—AL—Mn alloy (Mg: AL: Mn (mass ratio) = remainder: 5-6: 1 or less) and the surface of the core metal by RIM molding A hot water heating experiment was conducted in the same manner as in Example 1 except that a steering wheel made of a foamed urethane resin coating layer having a specific gravity of 0.4 was used.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 0%. The time required for the operation of removing the urethane resin in the second step was 180 minutes.

Comparative Example 2 (Al alloy core + urethane resin coating layer having a specific gravity of 0.4: steering wheel → after removing the coating layer after 10 minutes of warm water immersion)
Instead of the steering wheel of Example 1, a cored bar made of an Al-Mg-Mn alloy (Al: Mg: Mn (mass ratio) = balance: 2.5-4: 0.4-0.6), A hot water heating experiment was conducted in the same manner as in Example 1 except that a steering wheel comprising a cored bar and a coating layer made of urethane foam with a specific gravity of 0.4 formed on the surface of the cored bar by RIM molding was used. went.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 0%. The time required for the operation of removing the urethane resin in the second step was 18 minutes.

(5) Medium temperature mineral oil heating experiment (120-140 ° C)
Example 19 (Mg alloy cored bar + urethane resin coating layer having a specific gravity of 0.4, steering wheel → medium temperature mineral oil immersed for 15 minutes, then coating layer removal work → cored bar degreasing)
(A) First step (a-1) As an experimental oil tank (container), 40 liters of vegetable oil was prepared in a cooking zundo (inner diameter 430 mm, depth 455 mm), and the vegetable oil was heated. . Waste oil of cutting oil was used as mineral oil.

    (A-2) When the temperature of the vegetable oil reached 180 ° C., the steering wheel was (immersed), and after the addition (immersion), the temperature was adjusted so that the vegetable oil was in the range of 180 to 200 ° C. The steering wheel is made of a Mg-AL-Mn alloy (Mg-AL-Mn alloy (Mg: AL: Mn (mass ratio) = balance: 5-6: 1 or less)) and a surface of the core metal. A steering wheel composed of a foamed urethane resin coating layer having a specific gravity of 0.4 formed by RIM molding was used.

    (A-3) The first step was completed 15 minutes after the steering wheel was introduced. After completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2.7%.

(B) Second Step After the completion of the first step, the steering wheel is immediately pulled up from the oil tank, and while the urethane resin is swollen and softened, the rim portion and spoke of the steering wheel are manually operated using a resin spatula. The coating layer (urethane resin) of the part and the boss part was removed (the core metal and the resin layer were separated, and the coating layer was recovered in this step), and the second step was completed. The time required for removing the urethane resin was 4 minutes. The recovered coating layer (urethane resin) can be used for industrial waste treatment or recycling.

(C) Third step After the second step, the core after removing the coating layer is degreased and washed (collecting the core) in the following steps (1) to (3), and the third step is completed. (See FIGS. 2A and 2B). That is, (1) The surface (oil) of the metal core after removing the coating layer was wiped with a waste cloth. (2) Next, the core metal wiped with the waste was immersed in an ultrasonic cleaner filled with a degreasing solvent (oscillation frequency 28 KHz), and degreased and cleaned. (3) The degreased and washed cored bar was washed with water and dried with hot air. As the degreasing solvent, a cleaning liquid having a ratio of water: detergent (chemical name) Techniclean 200 EF) = 10: 1 (volume ratio) was used. The washing (drying) time in this step according to the above (1) to (3) was 15 minutes. The collected metal core can be recycled for steering wheel manufacturing or alloy ingot manufacturing. The degreasing solvent (cleaning liquid) used for the degreasing cleaning can also be used for industrial waste treatment or recycling after recovery.

Example 20 (Al alloy core + steer wheel of urethane resin coating layer having a specific gravity of 0.4 → middle temperature mineral oil immersed for 15 minutes, then coating layer removal operation → core metal degreasing and cleaning)
Instead of the steering wheel of Example 19, a cored bar made of an Al-Mg-Mn alloy (Al: Mg: Mn (mass ratio) = balance: 2.5-4: 0.4-0.6), A high temperature oil heating experiment was conducted in the same manner as in Example 19 except that a steering wheel composed of a foamed urethane resin coating layer having a specific gravity of 0.4 formed by RIM molding on the core metal surface was used.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2.7%. The time required for the operation of removing the urethane resin in the second step was 4 minutes.

(6) High temperature mineral oil heating experiment (180-200 ° C)
Example 21 (Mg alloy cored bar + urethane resin coating layer with specific gravity of 0.4 steering wheel → high temperature mineral oil immersed for 20 minutes, then coating layer removal work → cored bar degreasing)
(A) First step (a-1) As an experimental oil tank (container), 40 liters of vegetable oil was prepared in a cooking zundo (inner diameter 430 mm, depth 455 mm), and the vegetable oil was heated. . Waste oil of cutting oil was used as mineral oil.

    (A-2) When the temperature of the vegetable oil reached 180 ° C., the steering wheel was (immersed), and after the addition (immersion), the temperature was adjusted so that the vegetable oil was in the range of 180 to 200 ° C. The steering wheel is made of a Mg-AL-Mn alloy (Mg-AL-Mn alloy (Mg: AL: Mn (mass ratio) = balance: 5-6: 1 or less)) and a surface of the core metal. A steering wheel composed of a foamed urethane resin coating layer having a specific gravity of 0.4 formed by RIM molding was used.

    (A-3) The first step was completed 20 minutes after the steering wheel was introduced. After completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2.7%.

(B) Second Step After the completion of the first step, the steering wheel is immediately pulled up from the oil tank, and while the urethane resin is swollen and softened, the rim portion and spoke of the steering wheel are manually operated using a resin spatula. The coating layer (urethane resin) of the part and the boss part was removed (the core metal and the resin layer were separated, and the coating layer was recovered in this step), and the second step was completed. The time required for removing the urethane resin was 4 minutes. The recovered coating layer (urethane resin) can be used for industrial waste treatment or recycling.

(C) Third step After the second step, the core after removing the coating layer is degreased and washed (collecting the core) in the following steps (1) to (3), and the third step is completed. (See FIGS. 2A and 2B). That is, (1) The surface (oil) of the metal core after removing the coating layer was wiped with a waste cloth. (2) Next, the core metal wiped with the waste was immersed in an ultrasonic cleaner filled with a degreasing solvent (oscillation frequency 28 KHz), and degreased and cleaned. (3) The degreased and washed cored bar was washed with water and dried with hot air. As the degreasing solvent, a cleaning liquid having a ratio of water: detergent (chemical name) Techniclean 200 EF) = 10: 1 (volume ratio) was used. The washing (drying) time in this step according to the above (1) to (3) was 15 minutes. The collected metal core can be recycled for steering wheel manufacturing or alloy ingot manufacturing. The degreasing solvent (cleaning liquid) used for the degreasing cleaning can also be used for industrial waste treatment or recycling after recovery.

Example 22 (Al alloy core + steer wheel of urethane resin coating layer with specific gravity of 0.4 → high temperature mineral oil immersed for 20 minutes, then coating layer removal operation → core metal degreasing and cleaning)
Instead of the steering wheel of Example 21, a cored bar made of an Al-Mg-Mn alloy (Al: Mg: Mn (mass ratio) = balance: 2.5-4: 0.4-0.6), A high temperature oil heating experiment was conducted in the same manner as in Example 19 except that a steering wheel composed of a foamed urethane resin coating layer having a specific gravity of 0.4 formed by RIM molding on the core metal surface was used.

  As a result, after completion of the first step, the swelling ratio of the urethane resin immediately after pulling up the steering wheel (within 1 minute) was 2.7%. The time required for the operation of removing the urethane resin in the second step was 4 minutes.

Comparative Example 3 (Experimental trial of Example 1 of Patent Document 1 using a steering wheel n of an Al alloy core + urethane resin coating layer having a specific gravity of 0.4)
(A) Pretreatment process The rim part, spoke part, and boss part of the steering wheel were each cut with a cutter knife so as to reach the core metal. The cut length was about 2 cm, and the cut interval was about 10 cm. The steering wheel has a core metal made of an Mg-AL-Mn alloy (Mg: AL: Mn (mass ratio) = remainder: 5-6: 1 or less) and a specific gravity of 0 formed on the surface of the core metal by RIM molding. A steering wheel comprising a coating layer made of foamed urethane resin (4) was used. The time required for the pretreatment process was 2 minutes.

(B) First step (b-1) As an experimental alkaline stripper tank (container), 40 liters of alkaline stripper is prepared in a cooking zundo (inner diameter 430 mm, depth 455 mm). Heated. The alkaline stripping solution used contained 3.5 wt% potassium hydroxide, 2.5 wt% sodium hydroxide, 20 wt% anionic surfactant, and 40 wt% diethylene glycol monoethyl ether. The temperature of the liquid used in each step was measured using a K thermocouple.

    (B-2) When the temperature of the alkali stripping solution reached 70 ° C., the steering wheel in which the cut was formed in the pretreatment step was immersed, and the temperature was adjusted so that the alkali stripping solution maintained 70 ° C. after the immersion. The steering wheel was composed of a core metal made of Mg—Al alloy (see FIGS. 2A and 2B) and a coating layer made of urethane foam (specific gravity 0.4) formed by RIM molding.

    (B-3) The first step was completed 10 minutes after the immersion of the steering wheel.

(B) Second Step After the completion of the first step, the steering wheel is pulled up from the alkaline stripping solution tank, and then the cooking zundo (1) for the experimental first cleaning water tank (container) filled with 40 liters of the first cleaning water ( The steering wheel was immersed in a diameter of 43 cm) and washed with water. After the water washing, the steering wheel was pulled up from the first washing water tank, and the second step was finished. Washing with water was performed at room temperature. The time required for the water washing in the second step was 1 minute.

(C) Third step (c-1) As an experimental acid stripper tank (container), prepare 40 liters of acid stripper in a cooking zundo (inner diameter 430 mm, depth 455 mm). Heated. The acid stripping solution used was an organic acid containing 5 wt% formic acid, 30 wt% aromatic alcohol, and 30 wt% ethylene glycol monobutyl ether.

    (C-2) When the temperature of the alkaline stripping solution reaches 60 ° C, the steering wheel after the second step is immersed in the acid stripping solution tank, and the temperature is adjusted so that the acid stripping solution maintains 60 ° C after the immersion. did.

    (C-3) Ten minutes after immersion of the steering wheel, the third step was completed.

(D) Fourth Step After the completion of the fourth step, the steering wheel is lifted from the acid stripping solution tank, and then a cooking zundo (second container for experiment) filled with 40 liters of the second cleaning water (container) ( The steering wheel was immersed in a diameter of 43 cm) and washed with water. After completion of the water washing, the steering wheel was pulled up from the second washing water tank, and the fourth step was completed. Washing with water was performed at room temperature. The time required for the water washing in the fourth step was 2 minutes.

(E) Fifth step (e-1) As an experimental alkaline solution tank (container), 40 liters of alkaline solution was prepared in a cooking zundo (inner diameter 430 mm, depth 455 mm). An alkaline solution containing 5 wt% sodium hydroxide was used.

    (E-2) The steering wheel after completion of the fourth step was immersed in an alkaline solution bath, and the temperature of the alkaline solution after immersion was adjusted so as to maintain a normal temperature.

    (E-3) Five minutes after the immersion of the steering wheel, the fifth step was completed.

(F) Sixth step After completion of the fifth step, the steering wheel is pulled up from the alkaline bath, and then the cooking zundo (diameter) of the second cleaning water tank (container) for experiments filled with 40 liters of the third cleaning water. 43 cm), the steering wheel was immersed and washed with water. After completion of the water washing, the steering wheel was pulled up from the third washing water tank, and the fifth step was finished. Washing with water was performed at room temperature. The time required for the water washing in the sixth step was 2 minutes.

(G) Seventh step After the sixth step is completed, the coating layer remaining on the core metal is manually (physically) removed using a resin spatula (the core metal and the coating layer are separated and recovered). Seven steps were completed. The time required for the operation of removing the coating layer (urethane resin) in the seventh step was 180 minutes.

  The time required from the pretreatment step to the end of the removal operation of the coating layer (urethane resin) in the seventh step was 212 minutes.

  The results summarized for the above-described Examples and Comparative Examples are shown in Table 1 below.

The evaluation criteria for “workability” in Table 1 are as follows:
A: Work can be done easily in a short time (within 30 minutes for the entire process)
○: Compared with ◎, it takes time and takes a little time (the whole process exceeds 30 minutes and within 60 minutes)
Δ: Compared with ○, it takes time and takes a little time (the whole process exceeds 60 minutes and is within 90 minutes)
X: It takes a considerable amount of time and takes a lot of man-hours (the whole process exceeds 90 minutes).

The evaluation criteria for “safety” in Table 1 are as follows:
◎: Work without problems taking safety into consideration ○: Work without problems with some maintenance and management △: Work can be done by preparing a work environment such as large maintenance exhausts ×: Consider safety Even work cannot be done.

Evaluation criteria for “post-treatment” in Table 1 are as follows:
◎: No post-treatment with solvent ○: Simple solvent treatment required △: Solvent treatment using extensive maintenance required ×: Unusable.

The evaluation criteria for “Environment” in Table 1 are as follows:
◎: Wastewater treatment unnecessary ○: Simple wastewater treatment △: Large-scale wastewater treatment required ×: Unusable.

  From the results of Table 1, in the example, compared with the comparative example, the coating layer is removed by taking it out of the water or oil while being swollen and softened by impregnating with hot water or hot oil at a predetermined temperature. Thus, the coating layer (urethane resin) could be removed from the steering wheel in a short time with high work efficiency.

  In this example, the urethane resin is allowed to swell and soften in heated water or oil without being dissolved (peeled) using an alkali stripping solution or an acid stripping solution as in the comparative example. Thus, the bonding strength with the core metal surface and the mechanical strength can be greatly reduced. The covering layer (urethane resin) can be easily removed in a short time by performing the urethane resin removal operation in such a state (hot, soft and sticky state). That is, like chemical treatment (comparative example), it takes a lot of man-hours, work efficiency is poor, and if it is swollen and soft without taking post-treatment or environmental / safety measures, It has been confirmed that it can be easily removed in a short period of time simply by making a cut with a resin spatula and removing it.

11 Pretreatment process,
13 First step,
15 Second step,
17 Third step 21 Steering wheel,
21 'Steering wheel in swollen and softened state,
22 Rim part,
22 'swollen, softened rim,
23 coating layer,
23 'swollen, softened coating layer (urethane resin),
24 spokes,
24 'spokes in swollen and softened state,
25 Incised part cut in the pretreatment process,
25a Incised part cut in the second step,
27 water,
27 'oil,
29 Aquarium,
29 'oil tank,
31 Coil heater,
33 Core,
33a cored metal with oil attached,
35 Faucet,
37 Degreasing solvent.

Claims (12)

In a method of removing a coating layer containing the urethane resin from a composite material (referred to as a metal / urethane composite material) having a cored bar and a coating layer containing a urethane resin formed on the surface of the cored bar (referred to as a urethane removing method),
A first step of placing the metal / urethane composite in water or oil heated to a predetermined temperature for a predetermined time;
After the first step, the second step of taking out the metal / urethane composite from water or oil and removing the coating layer within a predetermined time;
A method for removing urethane from a metal / urethane composite material, comprising:   The temperature of the water heated to the predetermined temperature in the first step is in the range of 40 to 100 ° C, and the temperature of the oil heated to the predetermined temperature is in the range of 40 to 200 ° C. The urethane removal method as described.   The time in which the metal / urethane composite material in the first step is placed in water heated to a predetermined temperature is in the range of 10 minutes to 20 minutes, and the time in which the metal / urethane composite material is placed in oil heated to the predetermined temperature is 10 minutes to 20 minutes. The urethane removal method according to claim 1, wherein the urethane removal method is within a range of minutes.   When the metal / urethane composite material is taken out of water or oil after the first step, the swelling ratio of the urethane resin in the coating layer is 0.5% or more when water is used. The urethane removal method according to any one of claims 1 to 3, wherein when used, the content is 0.5% or more.   The time for removing the coating layer within the predetermined time of the second step is within 40 minutes when water is used in the first step, and within 40 minutes when oil is used in the first step. The urethane removal method according to any one of claims 1 to 4.   The urethane removal method according to any one of claims 1 to 5, wherein the core metal material is a magnesium alloy or an aluminum alloy. When using oil in the first step,
The urethane removing method according to any one of claims 1 to 6, further comprising a third step of degreasing and washing the core after the coating layer is removed after the second step.   The time required for urethane removal is within 60 minutes when water is used in the first step, or within 80 minutes when oil is used in the first step. The urethane removal method of any one of Claims 1.   The swelling ratio of the urethane resin in the coating layer at the end of the second step is 0.5% or more when water is used in the first step, and 0 when oil is used in the first step. The urethane removal method according to any one of claims 1 to 7, wherein the urethane removal method is at least 5%. When the coating layer has a multilayer structure in which the coating layer contains a urethane resin, as a pretreatment step before the first step,
The method of any one of claims 1 to 9, further comprising: (1) forming a mechanical damage on the coating layer; or (2) cutting a stitched portion of the leather material of the outer layer of the coating layer. The method for removing urethane according to Item.   A coating layer containing a urethane resin is formed on the surface of the core metal using the core metal obtained by the removing method according to any one of claims 1 to 10, and is regenerated as a metal / urethane composite material. Recycled metal / urethane composite material.   A cored bar obtained by the removing method according to any one of claims 1 to 10, is heated and melted and recycled as an ingot.