Polyurethane foam molded body, seat pad, and method for producing polyurethane foam molded body

Abstract

Provided is a polyurethane foam molded body having satisfactory hardness and strength, by using a pulverized product of polyurethane foam. The present invention pertains to a polyurethane foam molded body containing more than 0 mass% to not more than 15 mass% of a powder which is a pulverized product of polyurethane foam.

Description

Polyurethane foam molded article, sheet pad, and method for manufacturing polyurethane foam molded article

[0001] This invention relates to a polyurethane foam molded article, a sheet pad, and a method for manufacturing a polyurethane foam molded article.

[0002] Polyurethane foam is widely used in automotive seat pads, mattress cushioning, shock absorbers, and other applications. Because polyurethane foam is made of a thermosetting resin with a three-dimensional mesh structure, recycling requires special techniques.

[0003] As an innovative approach, a polyurethane foam molded article has been proposed in which the pulverized material of recycled polyurethane foam is used as a mixed composition of polyol and polyisocyanate, and this composition is foamed (Patent Document 1).

[0004] Japanese Patent Publication No. 2023-39041

[0005] However, the polyurethane foam molded articles proposed in Patent Document 1 were developed with a focus on properties such as sound absorption and vibration damping, and the pulverized polyurethane foam used in the specific examples is pulverized rigid polyurethane foam, prepared using sieves with opening diameters of 3 mm or 10 mm. Such polyurethane foam molded articles have significantly lower physical properties such as hardness and strength compared to polyurethane foam molded articles without added pulverized material, making them unsuitable for applications such as automobile seat pads.

[0006] The present invention aims to provide a polyurethane foam molded article having good hardness and strength, for example in a flexible polyurethane foam, using pulverized polyurethane foam, along with a method for producing the same.

[0007] The inventors of this invention discovered that the problem can be solved by finely grinding the pulverized polyurethane foam to a powder level and specifying the amount to be used, and thus completed the present invention.

[0008] The gist of the present invention is as follows: [1] A polyurethane foam molded article containing more than 0% by mass and 15% by mass or less of powder which is pulverized polyurethane foam. [2] A polyurethane foam molded article of [1] obtained by foaming a composition which contains a polyol, a polyisocyanate, and powder which is pulverized polyurethane foam. [3] A polyurethane foam molded article of [1] or [2] in which the powder which is pulverized polyurethane foam has a volume-based median diameter of less than 50 μm. [4] A polyurethane foam molded article of any of [1] to [3] in which the powder which is pulverized polyurethane foam is pulverized soft polyurethane foam. [5] A polyurethane foam molded article of any of [1] to [4] which is a soft polyurethane foam molded article. [6] A sheet pad made of any of the polyurethane foam molded articles of [1] to [5]. [7] A method for producing a polyurethane foam molded article, comprising the step of foaming a composition containing a polyol, a polyisocyanate, and a powder which is a pulverized polyurethane foam, wherein the composition contains the powder which is a pulverized polyurethane foam in an amount greater than 0% by mass and less than or equal to 15% by mass. [8] The method for producing a polyurethane foam molded article according to [7], wherein, in preparing the composition, the powder which is a pulverized polyurethane foam and water are mixed. [9] The method for producing a polyurethane foam molded article according to [8], wherein a dust explosion is prevented by mixing the powder which is a pulverized polyurethane foam and water.

[0009] According to the present invention, a polyurethane foam molded article having good hardness and strength, for example in a flexible polyurethane foam, can be provided using pulverized polyurethane foam, along with a method for manufacturing the same.

[0010] The present invention will be described in detail below.

[0011] <Polyurethane Foam Molded Article> The polyurethane foam molded article of the present invention contains a powder which is a pulverized polyurethane foam in an amount of more than 0% by mass and 15% by mass or less.

[0012] The powder (hereinafter also simply referred to as "powder") which is the pulverized material of polyurethane foam, may be pulverized material of flexible polyurethane foam, semi-rigid polyurethane foam, or rigid polyurethane foam. From the viewpoint of ensuring good hardness and strength in the polyurethane foam molded article, pulverized material of flexible polyurethane foam is preferred. The polyurethane foam in the powder may be open-cell foam or closed-cell foam. From the viewpoint of circular economy, it is preferable to use polyurethane foam of the sheet pad type. The polyurethane foam in the powder may be one type only, or two or more types in combination.

[0013] In this invention, finely ground polyurethane foam is used. In this specification, "powder" refers to the median diameter (D) based on volume. ５０ This refers to materials with a median diameter (D) of 80 μm or less. Within this range, good hardness and strength can be easily ensured in polyurethane foam molded articles. ５０ The median diameter (D) is preferably less than 50 μm, and more preferably 45 μm or less. ５０ The lower limit of the particle size is not particularly limited, but can be, for example, 10 μm or more. To avoid increased costs and to ensure good handling, it is preferably 20 μm or more, more preferably 30 μm or more, and even more preferably 40 μm or more.

[0014] Cumulative 90% particle size (D) based on volume of powder ９０ The thickness of the material is preferably 100 μm or less, and more preferably 60 μm or less, from the viewpoint of obtaining good hardness and strength.

[0015] The volume-based median diameter and cumulative 90% particle diameter can be measured by the measurement method described in the examples.

[0016] The powder content is 15% by mass or less, preferably 10% by mass or less, when the polyurethane foam molded article is considered to be 100% by mass. Within this range, good hardness and strength can be easily ensured in the polyurethane foam molded article. The powder content is greater than 0% by mass, preferably 1% by mass or more, and more preferably 5% by mass or more, from the viewpoint of good recyclability.

[0017] Polyurethane foam molded articles may be flexible, semi-rigid, or rigid. In particular, flexible polyurethane foam molded articles are advantageous because they have a greater effect in suppressing the deterioration of physical properties such as hardness and strength due to the addition of powdered polyurethane foam.

[0018] The urethane composition of the polyurethane foam molded article (polyol component and polyisocyanate component, etc.) and the urethane composition of the powdered polyurethane foam (polyol component and polyisocyanate component, etc.) may be the same or different.

[0019] The density of the polyurethane foam molded article is not particularly limited; for example, a density of 30 to 90 kg / m³ as measured according to JIS K 7222:2005 is acceptable. ３ It can be, preferably 40 to 80 kg / m ３ That is the case.

[0020] The size of the cells formed from the resin skeleton of a polyurethane foam molded body is not particularly limited. For example, if the cell diameter is measured for cells in a scan image obtained by an X-ray CT scan and the average value of the cell diameter is calculated, the average value (average cell diameter) can be 10 to 70 μm, preferably 30 to 70 μm.

[0021] From the viewpoint of suppressing the deterioration of physical properties such as hardness and strength due to the blending of powdered polyurethane foam, it is preferable that the average cell diameter of the polyurethane foam molded article be larger than the volume-based median diameter of the powdered polyurethane foam. The average cell diameter of the polyurethane foam molded article can be 0.5 to 2 times the volume-based median diameter of the powder, and is preferably 1 to 2 times.

[0022] The polyurethane foam molded article of the present invention can have a hardness in the range of 80 to 350 N at 23°C, as measured in accordance with JIS K6400-2 D method.

[0023] <Method for Manufacturing Polyurethane Foam Molded Articles> The method for manufacturing polyurethane foam molded articles is described below.

[0024] The present invention relates to a method for producing a polyurethane foam molded article, which includes a step of foaming a composition containing a polyol, a polyisocyanate, and a powder which is pulverized polyurethane foam. The amount of the pulverized polyurethane foam powder contained in the composition is 15% by mass or less, preferably 10% by mass or less, when the composition is considered to be 100% by mass. Within this range, good hardness and strength can be easily ensured in the resulting polyurethane foam molded article. The powder content is greater than 0% by mass, and from the viewpoint of good recyclability, it is preferably 1% by mass or more, and more preferably 5% by mass or more.

[0025] The powder, which is the pulverized material of polyurethane foam, can be obtained by pulverizing polyurethane foam, and the manufacturing method of the present invention may include the step of pulverizing polyurethane foam to obtain powder.

[0026] The polyurethane foam to be crushed includes scraps, defective products, and used polyurethane foam that is scheduled to be discarded, which are generated during the manufacturing process of polyurethane foam.

[0027] Grinding methods include compression grinding (e.g., roller mills) and grinding by impact or shock (e.g., jet mills). High-speed rotary grinders (e.g., hammer mills, pin mills) and container-driven mills (e.g., rotary mills, vibratory mills, planetary mills) may also be used. Among these, a combination of roller mills and jet mills is preferred from the viewpoint of finer grinding.

[0028] Grinding can be carried out dry or wet, but wet grinding is preferred because it easily avoids the risk of dust explosions caused by the powder. For example, grinding can be done by adding water. When grinding is done wet, it is preferable to dry the powder after grinding.

[0029] The pulverized polyurethane foam may be classified as appropriate. The means of classification are not particularly limited and include sieving, etc. By classification, the median diameter (D) of the powder based on volume can be determined. ５０ ) can be adjusted.

[0030] A composition can be prepared by mixing powdered polyurethane foam with polyols and polyisocyanates. When preparing the composition, mixing water with the powder helps to avoid the risk of dust explosions. Water can also function as a blowing agent.

[0031] The polyol is not particularly limited and examples include polyether polyols, polyester polyols, polyether polyester polyols, and polymer polyols (generally, those in which organic particles are dispersed in a polyether polyol).

[0032] Examples of polyether polyols include compounds obtained by adding alkylene oxides such as propylene oxide and ethylene oxide to polyols such as ethylene glycol, glycerin, and sorbitol.

[0033] Examples of polyester polyols include those obtained by polycondensation reactions of polyols such as ethylene glycol, glycerin, and sorbitol with polycarboxylic acids such as malonic acid, maleic acid, succinic acid, adipic acid, tartaric acid, sebacic acid, oxalic acid, phthalic acid, terephthalic acid, and trimellitic acid; and ring-opening polymers of cyclic esters such as polycaprolactone.

[0034] Examples of polyether polyester polyols include compounds obtained by reacting an intermediate compound, which is acquired by adding an alkylene oxide such as propylene oxide or ethylene oxide to a polyol such as ethylene glycol, glycerin, or sorbitol, with a polycarboxylic acid such as malonic acid, maleic acid, succinic acid, adipic acid, tartaric acid, sebacic acid, oxalic acid, phthalic acid, terephthalic acid, or trimellitic acid.

[0035] Examples of the polymer polyol include those in which polymer fine particles such as polyacrylonitrile and polyacrylonitrile / styrene copolymer are dispersed in a specific polyol.

[0036] As the polyol, natural polyols such as palm oil-derived polyol, castor oil-derived polyol, and soybean oil-derived polyol may be used.

[0037] The polyol may be used alone or in combination of two or more in any ratio.

[0038] The polyisocyanate is not particularly limited, and examples thereof include aromatic polyisocyanates, aliphatic polyisocyanates, and modified polyisocyanates obtained by modifying them. The aliphatic polyisocyanate may be an alicyclic polyisocyanate.

[0039] Examples of the aromatic polyisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, xylylene diisocyanate, polymethylene polyphenyl diisocyanate, and the like.

[0040] Examples of the aliphatic polyisocyanate include hexamethylene diisocyanate and the like. Also included are alicyclic polyisocyanates such as cyclohexylmethane diisocyanate, cyclohexane diisocyanate, and isophorone diisocyanate.

[0041] The polyisocyanate may be used alone or in combination of two or more in any ratio.

[0042] The amount of the polyisocyanate used is preferably such that the isocyanate index is usually about 80 to 130. If the isocyanate index is 80 or more, poor shrinkage of the obtained polyurethane foam can be sufficiently suppressed, and if it is 130 or less, foam collapse can be sufficiently suppressed.

[0043] The isocyanate index is expressed as a percentage of the equivalent ratio of isocyanate groups of polyisocyanate to active hydrogen groups such as hydroxyl groups of polyols and foaming agents (water).

[0044] The composition may further contain crosslinking agents, foaming agents, foam stabilizers, catalysts, colorants such as pigments, antioxidants, flame retardants, ultraviolet absorbers, light stabilizers, antibacterial agents, and the like.

[0045] The crosslinking agent is not particularly limited and includes, for example, polyhydric alcohols such as diethylene glycol, polyethylene glycol, polypropylene glycol, glycerin, trimethylolpropane, pentaerythritol, and sorbitol; amines such as ethylenediamine, diethylenetriamine, hexamethylenediamine, hydrazine, diethyltoluenediamine, and diethylenetriamine; amino alcohols such as diethanolamine and triethanolamine; and compounds obtained by adding ethylene oxide or polypropylene oxide to these active hydrogen compounds. The crosslinking agent may be used alone or in combination of two or more in any ratio.

[0046] The blowing agent is not particularly limited and can be, for example, water, a low-boiling point organic compound, or carbon dioxide. Examples of low-boiling point organic compounds include hydrocarbons such as pentane; trichloromonofluoromethane, dichlorodifluoromethane, monochlorodifluoromethane, trichlorotrifluoroethane, and methylene chloride. The blowing agent may be used alone or in combination of two or more in any ratio.

[0047] The foam stabilizer is not particularly limited and examples include organopolysiloxanes, alkyl carboxylates, alkylbenzene sulfonates, etc. The foam stabilizer may be used alone or in combination of two or more in any ratio.

[0048] The catalyst is not particularly limited and examples include amine catalysts and metal catalysts.

[0049] Examples of amine catalysts include 6-dimethylamino-1-hexanol, tetramethylhexamethylenediamine, pentamethyldiethylenetriamine, dimethylcyclohexylamine, bis-(dimethylaminoethyl) ether, tetramethylpropylenediamine, trimethylaminoethylpiperazine, tetramethylethylenediamine, dimethylbenzylamine, methylmorpholine, ethylmorpholine, and triethylenediamine.

[0050] Examples of metal catalysts include stanus octate, dibutyltin dilaurate, and tin-based catalysts such as stannous 2-ethylhexylate.

[0051] The catalyst may be used alone, or two or more catalysts may be used in any ratio.

[0052] The method for obtaining a composition containing a polyol, a polyisocyanate, and a powder that is a pulverized polyurethane foam is not particularly limited. For example, a first raw material containing a polyol and a second raw material containing a polyisocyanate can be prepared, and then the first and second raw materials can be mixed. The powder that is a pulverized polyurethane foam may be blended into either the first or second raw material, or into both the first and second raw materials. It is preferable to blend it into the first raw material in order to prevent the reaction between the moisture contained in the powder and the polyisocyanate. It is also preferable to blend other optional components into the first raw material. Furthermore, by adding water to the powder first, the scattering of the powder can be prevented, and dust explosions can be prevented. With this method, the powder that is a pulverized polyurethane foam and the other components can be thoroughly mixed before the reaction between the polyol and the polyisocyanate proceeds.

[0053] In this way, recycling the powder, which is the crushed material of used polyurethane foam, makes it possible to reduce the environmental impact.

[0054] The method for manufacturing the polyurethane foam molded body of the present invention includes a step of foaming the above composition. At that time, any molding method can be used, for example, mold molding, slab molding, etc. are mentioned. In the case of mold molding, for example, the above composition is filled into a mold and foamed inside the mold to obtain a polyurethane foam molded body as a mold-molded product. The foaming conditions can be appropriately adjusted according to the raw materials used, the characteristics of the desired molded body, etc. In the case of mold molding, the temperature of the mold is set to 50 to 70 ° C and held for 3 to 7 minutes. In addition, the molded body after foaming may be subjected to defoaming treatment. When observing the cross section of the polyurethane foam molded body of the present invention, usually, powder that is a pulverized product of polyurethane foam can be confirmed.

[0055] The polyurethane foam molded body of the present invention is widely used in cushion materials such as automobile seats and mattresses, impact absorbing materials, etc. Since polyurethane foam is made of a thermosetting resin having a three-dimensional network structure, ingenuity is required for recycling.

[0056] The present invention is suitable for molding cushion materials such as seat pads, bedding such as pillows and mattresses, zabutons, pads for chairs, and pads for clothing.

[0057] Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples at all, and can be appropriately changed within the range not changing the gist.

[0058] <Preparation of pulverized product of polyurethane foam> Soft polyurethane foam was pulverized by a roll press (manufactured by Seishin Enterprise Co., Ltd., model number 150 type), and then pulverized using a jet mill (single track jet mill manufactured by Seishin Enterprise Co., Ltd.) to obtain a pulverized product 1 which is a powder. A pulverized product 2 was obtained in the same manner as the pulverized product 1 except that pulverization was performed only by the roll press. Regarding these powders, the volume-based cumulative 10% particle diameter (D １０ ), volume-based cumulative 50% particle diameter (median diameter, D ５０ ) and volume-based cumulative 90% particle diameter (D９０ ) are shown in Table 1.

[0059] The pulverized material 2 was sieved to remove particles larger than 50 μm, obtaining pulverized material 3, which is a powder. Based on the particle size distribution of pulverized material 2, the cumulative 10% particle size (D) by volume was calculated. １０ ), cumulative 50% particle size (median diameter, D) based on volume. ５０ ) and the cumulative 90% particle size (D) based on volume. ９０ The result was calculated. The results are shown in Table 1.

[0060]

[0061] <Preparation of Flexible Polyurethane Foam Molded Article> (Reference Example 1) Using 69.4 parts by mass of polypropylene glycol (manufactured by Mitsui Chemicals, Inc., trade name "EP902N", hydroxyl value 23 mg KOH / g) and 30.6 parts by mass of polymer polyol (manufactured by Sanyo Chemical Industries, Ltd., trade name "Sanix KC-863", hydroxyl value 23 mg KOH / g) as the main raw materials, and as auxiliary materials, 0.579 parts by mass of triethylenediamine (manufactured by Evonik, trade name "DABCO 33LV"), 0.347 parts by mass of bis(2-dimethylaminoethyl) ether (manufactured by Tosoh Corporation, trade name "TOYOCAT-ET33B"), and silicone foam stabilizer 1 (manufactured by Momentive Performance Materials Japan, trade name "Niax silicone") A polyol premix was prepared by mixing and stirring 0.3 parts by mass of L-3627J, 0.2 parts by mass of silicone foam stabilizer 2 (manufactured by Momentive Performance Materials Japan, product name "Niax silicon L-3647J"), and 2.1 parts by mass of water as a foaming agent.

[0062] A polyol premix and polyisocyanate (manufactured by Tosoh Corporation, product name "CORONATE(R) 1021") were mixed and stirred until the isocyanate index reached 100. The apparent density of the mixture was 72 kg / m³. ３ After pouring the material into the mold, the mold lid was closed and cured for 5 minutes to obtain polyurethane foam. The polyurethane foam was removed from the mold (demolished), subjected to a de-foaming treatment, and a flexible polyurethane foam molded body of Reference Example 1 was obtained.

[0063] (Example 1) An amount of pulverized material 1 was weighed to make up 10% by mass in the final polyurethane foam, and it was added to the polyol premix and pre-mixed. Then, a flexible polyurethane foam molded article was obtained in the same manner as in Reference Example 1, except that the polyol premix to which pulverized material 1 was added was used. The ratio of the polyol premix to which pulverized material 1 was added to the polyisocyanate was set so that the ratio of the polyol premix to the polyisocyanate before adding pulverized material 1 was the same as the ratio in Reference Example 1.

[0064] (Comparative Example 1) An amount of pulverized material 2 was weighed to make up 10% by mass in the final polyurethane foam, and it was added to the polyol premix and pre-mixed. A flexible polyurethane foam molded article was obtained in the same manner as in Example 1, except that the polyol premix to which pulverized material 2 had been added was used.

[0065] (Example 2) An amount of the pulverized material 3 was weighed so that it would constitute 10% by mass in the final polyurethane foam, and this was added to the polyol premix and pre-mixed. A flexible polyurethane foam molded article was obtained in the same manner as in Example 1, except that the polyol premix to which the pulverized material 3 had been added was used.

[0066] Density, hardness, elongation, tensile strength, tear strength, rebound elasticity, dry heat shrinkage (DRYSET), and wet heat shrinkage (WETSET) of the flexible polyurethane foam molded articles of Reference Example 1, Examples 1-2, and Comparative Example 1 were measured. The results are shown in Table 2. (1) Density: Density was measured at 23°C in accordance with the JIS K7222 method. (2) Hardness: Hardness was measured at 23°C in accordance with the JIS K6400-2 D method. (3) Elongation: Measured in accordance with the JIS K6400-5 method. (4) Tensile strength: Measured in accordance with the JIS K6400-5 method. (5) Tear strength: Measured in accordance with the JIS K6400-5 B method. (6) Rebound elasticity: Measured in accordance with the JIS K6400-3 method. (7) Dry heat shrinkage (DRYSET) and wet heat shrinkage (WETSET) were measured in accordance with JIS K6400-4 Method A.

[0067]

[0068] Table 2 shows that the polyurethane foam molded article of the present invention, as a flexible polyurethane foam, has good hardness and strength. By adding finely ground polyurethane foam to the powder level, the deterioration of physical properties was suppressed, or even improved, compared to when finer ground material was added.

[0069] According to the present invention, a polyurethane foam molded article having good hardness and strength can be provided using pulverized polyurethane foam, and it has high industrial utility.

Claims

1. A polyurethane foam molded article containing more than 0% by mass and 15% by mass or less of powder, which is a pulverized material of polyurethane foam.

2. A polyurethane foam molded article according to claim 1, comprising foaming a composition containing a polyol, a polyisocyanate, and a powder which is a pulverized product of the polyurethane foam.

3. The polyurethane foam molded article according to claim 1, wherein the powder, which is the pulverized material of the polyurethane foam, has a volume-based median diameter of less than 50 μm.

4. The polyurethane foam molded article according to claim 1, wherein the powder, which is the pulverized polyurethane foam, is the pulverized flexible polyurethane foam.

5. A polyurethane foam molded article according to any one of claims 1 to 4, wherein the polyurethane foam molded article is a flexible polyurethane foam molded article.

6. A seat pad made of a polyurethane foam molded body according to claim 5.

7. A method for producing a polyurethane foam molded article, comprising the step of foaming a composition containing a polyol, a polyisocyanate, and a powder which is a pulverized product of polyurethane foam, wherein the composition contains the powder which is a pulverized product of polyurethane foam in an amount of more than 0% by mass and 15% by mass or less.

8. The method for producing a polyurethane foam molded article according to claim 7, wherein, in preparing the composition, a powder which is a pulverized polyurethane foam is mixed with water.

9. A method for manufacturing a polyurethane foam molded article according to claim 8, wherein a dust explosion is prevented by mixing the powder, which is the pulverized material of the polyurethane foam, with water.

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