Polyurethane molded product and method for producing polyurethane molded product

Abstract

To provide a method for producing a polyurethane molded product, which has high strength even when recycled materials are used, and to provide the polyurethane molded product.SOLUTION: A method for producing a polyurethane molded product includes: a first step of mixing a polyurethane fragment 2, a first binder 3, and a binder fiber 4; and a molding step of feeding materials obtained after the first step into a mold and molding it by heating. The fragment 2 is made of polyurethane foam. The polyurethane foam includes rigid polyurethane foam and flexible polyurethane foam. The fragment 2 may also be made of crushed recycled material.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for producing a polyurethane molded article using mainly recycled pulverized material, and to a polyurethane molded article. [Background technology]

[0002] Conventionally, methods for recycling used urethane foams, etc. have been proposed. For example, according to the description in Patent Document 1, a method for recycling soft urethane foam involves uniformly mixing a finely ground product mainly composed of soft urethane foam with low-melting polyester staple fibers, filling this mixture almost uniformly in a molding machine, and heating and pressurizing the mixture in the molding machine at a temperature higher than the softening temperature of the low-melting polyester staple fibers to obtain a molded product.

[0003] The soft urethane foam or the treated object having the fibrous material attached thereto is processed into a finely ground product to such an extent that it can be uniformly mixed with the low-melting polyester staple fibers.The mixture of the two is then almost uniformly filled into a molding machine, and heated and pressurized at a temperature higher than the softening temperature of the low-melting polyester staple fibers, causing the low-melting polyester staple fibers to melt, and the low-melting polyester staple fibers and the ground product of the treated object to become one with each other, thereby obtaining a homogeneous, stable-quality, and highly durable molded product.

[0004] According to this, (a) a homogeneous, stable-quality, highly durable molded product can be obtained by heating and pressurizing a uniform mixture of ground material and low-melting polyester staple fibers at a temperature higher than the softening temperature of the low-melting polyester staple fibers. (b) Molding can be performed under conditions where the heating temperature inside the molding machine is higher than the softening temperature of the low-melting polyester staple fibers and lower than the fluidization temperature of the flexible polyurethane foam, thereby shortening molding time and saving energy. (c) Molding is performed at a heating temperature lower than the fluidization temperature of the flexible polyurethane foam, so thermal decomposition of the flexible polyurethane foam does not occur and the generation of hydrogen cyanide can be prevented. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 7-68550 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the conventional example shown in Patent Document 1 has the following problems. Molded products made by the recycling method, such as urethane foam, are reused as residential insulation materials and other uses. When workers install the molded products at construction sites, etc., they will be damaged if the molded products have low strength. The molded products made by the conventional example have a problem in that they do not have sufficient strength. As an example, under the conditions shown in Figure 5, the three-point bending strength is 3 N / cm 2 This is a low value.

[0007] The present invention is devised to solve the problems of the related art, and has an object to provide a method for producing a polyurethane molded article, and a polyurethane molded article, which can achieve high strength even when recycled materials are used. [Means for solving the problem]

[0008] A method for producing a polyurethane molded article according to a first aspect of the present invention includes a first step of mixing polyurethane pieces, a first binder, and binder fibers, and a molding step of feeding the material obtained after the first step into a mold and heat-molding the material.

[0009] According to this, the pieces are bound by the first binder and the binder fibers, so that the molded polyurethane article can have high strength.

[0010] The pieces may also be made of polyurethane foam. In this case, the polyurethane molding obtained can be used as a high-strength insulating material for housing and other building materials.

[0011] The first binder may be a moisture-curing binder, in which case the first binder mixed with the binder fibers adheres to the fragments and cures, thereby strengthening the binding force between the fragments.

[0012] A polyurethane molded article according to a second aspect of the present invention comprises polyurethane pieces, a first resin derived from a first binder, and a second resin derived from binder fibers.

[0013] In this case, the polyurethane molded article can have high strength because the pieces are covered with the first resin and the bonding strength between the pieces is increased by the second resin. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic diagram showing the structure of a polyurethane molded body 1 produced by the polyurethane molded body production method of the present invention. [Diagram 2] FIG. 1 is an explanatory diagram showing a first example of the steps of the method for producing a polyurethane molded article of the present invention. [Diagram 3] FIG. 2 is an explanatory diagram showing a second example of the steps of the method for producing a polyurethane molded article of the present invention. [Figure 4] 1 is a flowchart illustrating steps of a method for producing a polyurethane molded article according to the present invention. [Diagram 5] FIG. 1 is a diagram summarizing the evaluation results of each of the examples, comparative examples, and a conventional example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, a polyurethane molded body manufacturing method and a polyurethane molded body 1 embodying the present invention will be described with reference to the drawings. Note that the description of the embodiment of the invention and the drawings referred to are used to explain technical features that can be adopted by the present invention. The present invention is not limited thereto. The configuration of the device shown in the drawings is merely an illustrative example and is not intended to limit the present invention.

[0016] <Description of the polyurethane molding manufacturing method> The method for producing a polyurethane molded body will now be described. The method for producing a polyurethane molded body includes a first step of mixing polyurethane pieces 2, a first binder 3, and binder fibers 4, and a molding step of feeding the material from the first step into a mold 24 and molding it by heating.

[0017] The fragment 2 is made of foamed polyurethane. The foamed polyurethane includes hard polyurethane foam and soft polyurethane foam. The fragment 2 may also be made of ground recycled material.

[0018] Moreover, the first binder 3 is a moisture-curing binder. When the fragments 2 are polyurethane foam, the first binder 3 is, for example, an isocyanate prepolymer that is liquidized by reacting an isocyanate 23 with a polyol 22. The first binder 3 is mixed with the binder fibers 4 in a liquid state, so it is easy to mix and adheres evenly to the fragments 2. The first binder 3 then chemically reacts with moisture in the air and hardens.

[0019] <Description of molding process> Next, the molding process of the polyurethane molded body 1 will be described with reference to Figs. 2 to 4. The fragments 2 will be described in the case where rigid polyurethane foam is used. As shown in Fig. 4, first, a rigid polyurethane foam recovery process P1 is performed. Next, a rigid polyurethane foam crushing process P2 is performed to generate fragments 2, which are crushed material 21. The fragments 2 have a side length ranging from 0.5 mm to 50 mm. Also, as shown in Fig. 2, a liquid binder 5, which is an isocyanate prepolymer, is generated as the first binder 3 in a generation process P3 by reacting an isocyanate 23 with a polyol 22.

[0020] Next, as shown in Figures 2 and 3, a blending process P4 is carried out in which the fragments 2, the liquid binder 5 as the first binder 3, and the binder fiber 4 are put into a blender 20 and mixed. The blending process P4 corresponds to the first step. It is preferable to use a low melting point resin fiber with a core-sheath structure as the binder fiber 4. In this case, the melting point of the resin constituting the sheath is lower than that of the resin constituting the core. The weight ratio of the fragments 2, the binder fiber 4, and the liquid binder 5 is, for example, 100:5:10.

[0021] As shown in Figures 2 and 3, after the first step, the obtained material is put into a mold 24 (P5). In the example shown in Figure 2, the material is then compressed and molded (P6) while being heated using a mold 25. The heating temperature is 150°C, the pressure is 1 to 5 Pa, and the heating time is 10 minutes. After molding, the molded product is removed (P7) and cut out according to the intended use (P8), completing the polyurethane molded product 1. The example shown in Figure 2 is a case of molding by heating and compression. The isocyanate prepolymer crosslinks with the polyurethane, so that the liquid binder 5 becomes a first resin 13 (described later) and bonds firmly with the fragments 2.

[0022] The binder fibers 4 include low-melting-point polyester staple fibers with a sheath-core structure, and in the example shown in Fig. 2, the melting point is 150°C or less. In the low-melting-point polyester staple fibers with a sheath-core structure, the resin constituting the sheath is softened by heating and compression, and the low-melting-point polyester staple fibers are easily bonded to the fragments 2. In addition, the low-melting-point polyester staple fibers with a sheath-core structure are also easily bonded to the first resin 13 derived from the liquid binder 5, and the bonding strength between the fragments 2 is increased.

[0023] Another example will be described with reference to FIG. 3. After the first step, the obtained material is put into a mold 24 (P5), and then compressed by a mold 25 while introducing heated steam 28 into a steam hole 26, to perform compression molding (P16). In this case, the heating temperature is 100°C, and the heating time and pressurizing pressure are the same as in FIG. 2. After molding, the molded product is removed (P17), cut out according to the application (P18), and the polyurethane molded body 1 is completed. The example shown in FIG. 3 is a case of molding by heated steam compression. The low melting point polyester staple fiber with a core-sheath structure used in this case has a melting point of 100°C or less, and the resin constituting the sheath is softened by heated steam compression, making it easier to bond with the fragments 2. It is also easier to bond with the first resin 13, as in FIG. 2.

[0024] The liquid binder 5 hardens during the series of steps and becomes bonded to the pieces 2 as the first resin 13. Since the liquid component hardens during the process, a step of removing the liquid component is not required. The structure of the molded polyurethane molded body 1 will be described later.

[0025] <Effects of the polyurethane molding manufacturing method> The above-described method for producing a polyurethane molded body has the following advantages: In the method for producing a polyurethane molded body, the pieces 2, the first binder 3, and the binder fibers 4 are mixed and then heated and molded, so that the bonding strength between the pieces 2 is strong and a polyurethane molded body 1 with high strength can be produced.

[0026] The pieces 2 may also be made of polyurethane foam, and the polyurethane foam is cross-linked with the isocyanate prepolymer of the first binder 3, thereby increasing the bonding strength between the pieces 2. Thus, the molded polyurethane molded body 1 can be used as a high-strength insulating material for housing and other building materials.

[0027] In addition, since the first binder 3 is a moisture-curing binder, it is mixed with the binder fibers 4 in a liquid state and adheres to the fragments 2, and then hardens, thereby increasing the binding strength between the fragments 2. Since the first binder 3 hardens by chemically reacting with moisture in the air, there is no need to remove the liquid component, and the number of steps can be reduced.

[0028] <Description of polyurethane molding 1> Next, a polyurethane molded body 1 according to a second embodiment of the present invention will be described. As shown in Fig. 1, the polyurethane molded body 1 includes a polyurethane fragment 2, a first resin 13 derived from a first binder 3, and a second resin 14 derived from binder fibers 4. The polyurethane molded body 1 is produced by the polyurethane molded body production method already described.

[0029] 1, the first resin 13 is bonded to cover the periphery of the piece 2. The piece 2 contains foamed polyurethane, and the first resin 13 contains non-foamed polyurethane.

[0030] The first resin 13 has a tensile elongation of 200% or more. The pieces 2 have a tensile elongation of 120% or less. The pieces 2 are bonded together by the first resin 13 having a large tensile elongation acting as an adhesive.

[0031] 1, the second resin 14 is present inside and / or on the surface of the first resin 13. The second resin 14 contains low-melting-point polyester staple fibers. The low-melting-point polyester staple fibers have a melting point of 150° C. or less and have a core-sheath structure.

[0032] 1, between adjacent pieces 2 of the fragments 2, the first resins 13 are bonded to each other, or / and the first resin 13 and the second resin 14, or / and the second resins 14 are bonded to each other. In the low melting point polyester staple fiber, the melting point of the resin constituting the sheath is lower than that of the resin constituting the core. The resin constituting the sheath of the second resin 14 softens before the resin constituting the core, and is likely to bond to the first resin 13, and / or the fragments 2, and / or the second resins 14 themselves.

[0033] <Effects of polyurethane molding 1> The polyurethane molded body 1 described above has the following advantages: As shown in Fig. 1, the polyurethane molded body 1 has pieces 2 covered with the first resin 13, and the bonding force between the pieces 2 is further increased by the second resin 14, so that the polyurethane molded body 1 can have high strength.

[0034] Furthermore, since the first resin 13 of the polyurethane molded body 1 contains non-foamed polyurethane, the bonding strength is stronger and higher strength can be obtained.

[0035] Furthermore, the polyurethane molded body 1 can obtain a stronger bond and a higher strength because the first resin 13 has a higher tensile elongation than the fragments 2. In particular, rigid polyurethane foams generally have low elongation and tend to have low strength when used alone, but the first resin 13 that covers the fragments 2 has a high tensile elongation, which increases flexibility and increases strength.

[0036] Moreover, the polyurethane molded body 1 can have a higher strength because the bonding force between the pieces 2 is increased by the second resin 14. Furthermore, since the second resin 14 contains low-melting point polyester short fibers, it melts during hot molding to increase the adhesive effect and increase the bonding force between the pieces, thereby obtaining a higher strength.

[0037] Furthermore, in the polyurethane molded body 1, the first resins 13 are bonded together, or / and the first resin 13 and the second resin 14, or / and the second resins 14 are bonded together, so that the bonding strength between the fragments 2 is strong, and thus higher strength can be obtained. By including a plurality of bonding states, the polyurethane molded body 1 has higher strength than a single bonding state.

[0038] <Examples and Comparative Examples of Polyurethane Molded Article 1 of the Present Invention, and Comparison with Conventional Examples> Next, the results of comparative evaluation of the polyurethane molded article 1 of the present invention between the examples, comparative examples, and conventional examples will be described. Figure 5 summarizes the comparative evaluation results. There are three examples, A to C, two comparative examples, D and E, and two conventional examples, F and G.

[0039] The ground material 21 used in the examples, comparative examples, and conventional examples is a hard urethane foam chip, and the urethane foam used is manufactured by BASF INOAC Polyurethanes Co., Ltd. and has a product number of FORMLITE SL. The binder fiber 4 used in the examples and comparative examples is manufactured by Unitika Ltd. and has a product number of Melty 4080, and is made of polyethylene. The liquid binder 5 used in the examples and conventional examples is manufactured by BASF INOAC Polyurethanes Co., Ltd. and has a product number of FORMLITE 1150, and is blended with an isocyanate prepolymer.

[0040] The conditions for Examples A to C are explained, and the results are compared among the examples. Comparing Examples A and C, the materials used are both 1000g of crushed material 21, 50g of binder fiber 4, and 100g of liquid binder 5. The density of the molded product is both 50kg / m 3 and only the size of the pulverized material 21 is different. That is, A is in the range of 3 to 10 mm, while C is in the range of 10 to 30 mm. As a result, the three-point bending strength is 7 N / cm for A. 2 whereas C is 14N / cm 2 The larger the size of the pulverized material 21 is within a predetermined range, the higher the three-point bending strength is.

[0041] Comparing Examples A and B, the size of the pulverized material 21 used is in the range of 3 to 10 mm in both cases, but other conditions are different. The mass of the pulverized material 21 used is 1000 g for A and 1200 g for B. The mass of the binder fiber 4 used is 50 g for A and 60 g for B. The mass of the liquid binder 5 used is 100 g for A and 120 g for B. These are conditions for making a difference in the density of the molded product, and A is 50 kg / m 3 and B is 60 kg / m 3 As a result, the three-point bending strength is A = 7N / cm 2 whereas B is 10N / cm 2 The higher the density of the molded product, the higher the three-point bending strength.

[0042] Next, the Example and the Comparative Example are compared. The Comparative Example does not use binder fibers 4 as compared to the Example. Example A and Comparative Example D are compared, in which the size of the pulverized material 21 used is similar. Comparative Example D uses a larger mass of liquid binder 5, 200 g, than Example A. The other conditions are similar. As a result, the three-point bending strength of Comparative Example D is 4 N / cm 2 , which is lower than that of Example A. In addition, even when comparing Example C and Comparative Example E, in which the size of the crushed material 21 used is similar, the three-point bending strength of Comparative Example E is 7 N / cm, even though the mass of the liquid binder 5 used is 200 g, which is larger. 2 From the above results, when comparing the Examples and the Comparative Examples, it is evident that the use of binder fiber 4 results in a higher three-point bending strength.

[0043] Next, the Examples and the Conventional Examples are compared. The Conventional Examples are, for example, conditions conforming to the contents described in Patent Document 1. Conventional Example F is a condition compared to Example A, Conventional Example G is a condition compared to Example C, and Conventional Examples F and G are both examples that do not use liquid binder 5. As a result, the three-point bending strength of Conventional Example F is 3 N / cm 2 , which is lower than that of Example A. The three-point bending strength of Conventional Example G is 6 N / cm 2 , which is lower than the strength of Example C. From the above results, when comparing the Examples and the Conventional Example, it is found that the one using the liquid binder 5 has a higher three-point bending strength.

[0044] Next, the comparative example and the conventional example are compared. The comparative example and the conventional example are comparisons of cases where only either the binder fiber 4 or the liquid binder 5 is used. Between the comparative example D and the conventional example F, and between the comparative example E and the conventional example G, the mass and size of the pulverized material 21 used are the same. According to the comparison results, it can be seen that the three-point bending strength is higher when only the liquid binder 5 is used than when only the binder fiber 4 is used.

[0045] From the above-described comparative results, the polyurethane molded body 1 produced by the polyurethane production method of the present invention has a higher strength than the comparative example and the conventional example. Therefore, the polyurethane molded body 1 using recycled materials is suitable as a residential insulation material and other building materials. [Explanation of symbols]

[0046] 1 Polyurethane molding 2. Fragment 3 First Binder 4. Binder Fiber 13 Daiichi Resin 14 Second resin 24, 25 inch

Claims

1. A first step of mixing polyurethane shreds, a first binder, and binder fibers; A molding step of pouring the material after the first step into a mold and heat-molding it; A method for producing a polyurethane molded article comprising the steps of:

2. 2. The method for producing a polyurethane molded article according to claim 1, wherein the pieces are made of foamed polyurethane.

3. 3. The method for producing a polyurethane molded article according to claim 1, wherein the first binder is a moisture-curing binder.

4. A polyurethane molded article comprising a polyurethane piece, a first resin derived from a first binder, and a second resin derived from binder fibers.

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