Polyurethane foam and electronic equipment

Abstract

To provide polyurethane foam excellent in cushioning.SOLUTION: Polyurethane foam contains polymer particles having a core-shell structure including a core layer containing a rubber component. A density based on JIS K 6401:2011 of the polyurethane foam is 100-250 kg / m3.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to polyurethane foams and electronic devices. [Background technology]

[0002] Patent Document 1 discloses a polyurethane foam produced by a mechanical froth method. This polyurethane foam is obtained by mixing a foam-forming gas with a resin raw material containing a polyol, an isocyanate, and a foam stabilizer, and sandwiching the mixture between a substrate film and a surface protective film to react and harden. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-227392 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, polyurethane foams are required to have various properties, and these requirements are becoming stricter. For example, polyurethane foams with excellent cushioning properties are required. An object of the present disclosure is to obtain a polyurethane foam having excellent cushioning properties. The present disclosure can be realized in the following forms. [Means for solving the problem]

[0005] [1] A polymer particle having a core-shell structure with a core layer containing a rubber component, Density based on JIS K6401:2011 is 100kg / m 3 More than 250kg / m 3 Below is a polyurethane foam. Effect of the Invention

[0006] According to the present disclosure, a polyurethane foam having excellent cushioning properties can be obtained. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing a first example of an electronic device equipped with polyurethane foam. [Diagram 2] FIG. 13 is a diagram showing a second example of an electronic device including polyurethane foam. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Here, a preferred example of the present disclosure is given. [1] A polymer particle having a core-shell structure with a core layer containing a rubber component, Density based on JIS K6401:2011 is 100kg / m 3 More than 250kg / m 3 Below is a polyurethane foam. [2] The polyurethane foam according to [1], having a 50% compression hardness based on JIS K6254:2010 of 0.0080 MPa or less. [3] An electronic device comprising the polyurethane foam described in [1] or [2]. [4] A polymer particle having a core-shell structure with a core layer containing a rubber component, The thickness is 5 mm or less, Density based on JIS K6401:2011 is 250kg / m 3 Below is a polyurethane foam. [5] A polymer particle having a core-shell structure with a core layer containing a rubber component, Polyurethane foam with a 25% compression hardness of 0.0025 MPa or less based on JIS K6254:2010. [6] A polyurethane foam obtained by a mechanical froth method from a polyurethane foam composition containing a polyol and an isocyanate and an inert gas, The composition for a polyurethane foam contains polymer particles having a core-shell structure with a core layer containing a rubber component, Density based on JIS K6401:2011 is 250kg / m 3 Below is a polyurethane foam.

[0009] The present disclosure will be described in detail below. In this specification, when a numerical range is described using "-", the lower limit and the upper limit are included unless otherwise specified. For example, the description "10-20" includes both the lower limit "10" and the upper limit "20". In other words, "10-20" has the same meaning as "10 or more and 20 or less". In this specification, the upper limit and the lower limit of each numerical range can be arbitrarily combined.

[0010] 1. Polyurethane foam of the first embodiment The polyurethane foam of the first embodiment contains polymer particles having a core-shell structure (hereinafter, simply referred to as polymer particles). The core-shell structure has a core layer containing a rubber component. The polyurethane foam has a density of 100 kg / m based on JIS K6401:2011. 3 More than 250kg / m 3 The following is the result.

[0011] The polyurethane foam is preferably obtained from a polyurethane foam composition containing a polyol, an isocyanate, and polymer particles. The polyurethane foam composition may contain a filler, a foam stabilizer, a catalyst, an antioxidant, a moisture absorbent, etc. Each component of the composition will now be described.

[0012] (1) Polyol As the polyol, a polyol for polyurethane foam can be used, and suitable examples thereof include one or more of polyether polyol, polyester polyol, polyether ester polyol, and the like.

[0013] The polyether polyol is preferably at least one selected from the group consisting of polyether polyols obtained by adding an alkylene oxide, such as ethylene oxide (EO) or propylene oxide (PO), to a polyhydric alcohol, such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, glycerin, pentaerythritol, trimethylolpropane, sorbitol, or sucrose.

[0014] When the polyether polyol contains ethylene oxide (EO), it is preferable that the polyether polyol contains a low EO polyether polyol having an ethylene oxide addition rate of 1 mass% to 40 mass% and a high EO polyether polyol having an ethylene oxide addition rate of 60 mass% to 100 mass%. When the total amount of polyols is 100 mass parts, the low EO polyether polyol is preferably 30 mass parts to 40 mass parts, and the high EO polyether polyol is preferably 10 mass parts to 20 mass parts.

[0015] The number average molecular weight of the polyether polyol is not particularly limited. The number average molecular weight of the polyether polyol is preferably 8000 or less, more preferably 6000 or less, and even more preferably 5000 or less, from the viewpoint of suppressing the increase in liquid viscosity, reducing the influence of deterioration in fluidity, and facilitating thin-layer molding. The number average molecular weight of the polyether polyol is preferably 200 or more, more preferably 300 or more, and even more preferably 400 or more, from the viewpoint of suppressing reactivity, reducing initial thickening, increasing fluidity, and reducing hardness.

[0016] The number of functional groups of the polyether polyol is not particularly limited. The number of functional groups of the polyether polyol is preferably 2-5, more preferably 2-4, and further preferably 2 or 3. In the present disclosure, the number of functional groups means the average number of active hydrogen groups of each component contained in the polyol.

[0017] The content of the polyether polyol is preferably 70 parts by mass or more and 95 parts by mass or less, more preferably 75 parts by mass or more and 92 parts by mass or less, and even more preferably 80 parts by mass or more and 90 parts by mass or less, in terms of ensuring various physical properties of the polyurethane foam, when the total amount of the polyols is 100 parts by mass.

[0018] The polyester polyol is preferably one or more selected from the group consisting of polycaprolactone-based polyester polyols, adipate-based polyester polyols, and polycarbonate-based polyols. The polycaprolactone-based polyester polyol is preferably a polyester polyol obtained by ring-opening addition polymerization of lactones such as ε-caprolactone. The adipate-based polyester polyol is preferably a polyester polyol obtained by polycondensation of a multifunctional carboxylic acid and a multifunctional hydroxy compound. Among these polyester polyols, polycaprolactone-based polyester polyols are preferred.

[0019] Examples of the polyether ester polyol include those obtained by reacting the above-mentioned polyether polyol with a polybasic acid to form a polyester, and those having both polyether and polyester segments in one molecule.

[0020] The number average molecular weight of the polyol that is contained in the polyurethane foam composition in the largest amount among the polyols (hereinafter also referred to as the main polyol) is, from the viewpoints of increasing the viscosity and enhancing the reactivity, preferably 8000 or less, more preferably 6000 or less, and even more preferably 5500 or less. The number average molecular weight of the main polyether polyol is, from the viewpoints of ensuring the strength of the polyurethane foam, preferably 3000 or more, more preferably 4000 or more, and even more preferably 4500 or more.

[0021] The main polyol preferably has 2-5 functional groups, more preferably 2-4 functional groups, and even more preferably 2 or 3 functional groups.

[0022] The hydroxyl value of the main polyol is preferably 20 mgKOH / g or more, more preferably 25 mgKOH / g or more, and even more preferably 30 mgKOH / g or more. From the viewpoint of suppressing heat generation during foaming, the hydroxyl value of the main polyol is preferably 60 mgKOH / g or less, more preferably 50 mgKOH / g or less, and even more preferably 40 mgKOH / g or less. Therefore, the hydroxyl value of the main polyol is preferably 20 mgKOH / g or more and 60 mgKOH / g or less, more preferably 25 mgKOH / g or more and 50 mgKOH / g or less, and even more preferably 30 mgKOH / g or more and 40 mgKOH / g or less.

[0023] (2) Isocyanate The isocyanate may be one generally used in the production of polyurethane foam. The isocyanate preferably contains one or more MDI-based compounds selected from the group consisting of diphenylmethane diisocyanate (MDI), modified MDI, and polymeric MDI.

[0024] Diphenylmethane diisocyanate is, for example, 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,2'-diphenylmethane diisocyanate (2,2'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), and a mixture of two or more of these.

[0025] The modified MDI is, for example, a carbodiimide modified MDI, a urethane modified MDI, a uretoimine modified MDI, etc. The modified MDI preferably includes a carbodiimide modified MDI.

[0026] Polymeric MDI is a polyphenylene polymethylene polyisocyanate, and is, for example, a mixture of dinuclear MDI and trinuclear or higher polynuclear MDI. Polymeric MDI may be untreated crude MDI obtained by MDI synthesis reaction, or may be MDI obtained by separating a desired amount of monomeric MDI from the crude MDI by vacuum distillation to adjust the composition.

[0027] The isocyanate index (INDEX) is preferably from 80 to 120, more preferably from 85 to 110, and further preferably from 90 to 105. The isocyanate index is a value obtained by dividing the number of moles of isocyanate groups in an isocyanate by the total number of moles of active hydrogen groups such as hydroxyl groups of a polyol and water as a blowing agent, and multiplying the result by 100, and is calculated as [NCO equivalent of isocyanate / active hydrogen equivalent×100].

[0028] The isocyanate content is preferably 20 parts by mass or more and 45 parts by mass or less, more preferably 25 parts by mass or more and 40 parts by mass or less, and even more preferably 30 parts by mass or more and 35 parts by mass or less, relative to 100 parts by mass of the total polyol.

[0029] (3) Polymer particles with a core-shell structure Specifically, the polymer particles having a core-shell structure refer to rubber particles in which a part or all of the surface of a particulate core component, mainly composed of a crosslinked rubber-like polymer, is covered with a shell component by graft-polymerizing a polymer different from the core component. Examples of the core component include crosslinked rubber particles. The type of rubber used for the crosslinked rubber particles is not limited, and examples of the rubber include butadiene rubber, acrylic rubber, silicone rubber, butyl rubber, nitrile rubber, styrene rubber, synthetic natural rubber, and ethylene propylene rubber. Examples of the shell component include polymers polymerized from one or more monomers selected from the group consisting of acrylic acid esters, methacrylic acid esters, and aromatic vinyl compounds. It is preferable that the shell component is graft-polymerized to the core component and chemically bonded to the polymer constituting the core component. In addition, in consideration of dispersibility with polyol, it is preferable that the core-shell rubber particles include MBS (methyl methacrylate-butadiene-ethylene copolymer)-based polymers.

[0030] The particle size (volume average particle size) of the polymer particles is preferably from 10 nm to 2000 nm, more preferably from 50 nm to 800 nm, further preferably from 100 nm to 600 nm, and particularly preferably from 200 nm to 400 nm.

[0031] The content of the polymer particles is preferably 1 part by mass or more and 10 parts by mass or less, more preferably 1.5 parts by mass or more and 8.0 parts by mass or less, and even more preferably 2.0 parts by mass or more and 6.0 parts by mass or less, relative to 100 parts by mass of the total polyol.

[0032] In order to facilitate mixing with polyols and the like, the polymer particles are preferably added to the polyurethane foam composition as a polymer particle dispersion in which the polymer particles are dispersed in PPG (polypropylene glycol). The PPG in the polymer particle dispersion functions as a solvent. The weight ratio of the polymer particles to the PPG in the polymer particle dispersion is preferably 40:60-50:50.

[0033] The content of the polymer particle dispersion is preferably 1.0 parts by mass or more and 20 parts by mass or less, more preferably 2.0 parts by mass or more and 15 parts by mass or less, and even more preferably 3.0 parts by mass or more and 10 parts by mass or less, based on 100 parts by mass of the total polyol.

[0034] The content of the polymer particles having a core-shell structure in the polyurethane foam is preferably 0.5 parts by mass or more and 10 parts by mass or less, more preferably 1.0 parts by mass or more and 8 parts by mass or less, and even more preferably 1.5 parts by mass or more and 5 parts by mass or less, based on 100 parts by mass of the polyurethane foam.

[0035] (4) Filler The filler is preferably at least one selected from the group consisting of aluminum hydroxide, magnesium hydroxide, and calcium carbonate.

[0036] The content of the filler is preferably 5.0 parts by mass or more and 30 parts by mass or less, more preferably 10 parts by mass or more and 25 parts by mass or less, and even more preferably 15 parts by mass or more and 20 parts by mass or less, based on 100 parts by mass of the total polyol.

[0037] (5) Foam stabilizer The foam stabilizer is used to facilitate the foaming of the polyurethane foam composition. As the foam stabilizer, a known foam stabilizer that is usually used when the mechanical froth method is adopted, such as a silicone-based foam stabilizer, can be used.

[0038] The content of the foam stabilizer is preferably 3.0 parts by mass or more and 25 parts by mass or less, more preferably 5.0 parts by mass or more and 20 parts by mass or less, and even more preferably 10 parts by mass or more and 15 parts by mass or less, based on 100 parts by mass of the total polyol.

[0039] (6) Catalyst The catalyst is mainly for promoting the urethane reaction between the polyol and the isocyanate. The organometallic catalyst is preferably at least one selected from the group consisting of an organoferric compound, an organotin compound, an organobismuth compound, an organolead compound, and an organozinc compound.

[0040] The catalyst content is preferably 3.0 parts by mass or more and 20 parts by mass or less, more preferably 5.0 parts by mass or more and 10 parts by mass or less, and even more preferably 7.0 parts by mass or more and 8.0 parts by mass or less, relative to 100 parts by mass of the total polyol.

[0041] (7) Antioxidants The antioxidant is preferably a hindered phenol-based antioxidant from the viewpoint of reducing the content of volatile organic compounds.

[0042] The content of the antioxidant is preferably 0.1 parts by mass or more and 1.5 parts by mass or less, more preferably 0.2 parts by mass or more and 1.0 parts by mass or less, and even more preferably 0.3 parts by mass or more and 0.5 parts by mass or less, relative to 100 parts by mass of the total polyol.

[0043] (8) Moisture absorbent The moisture absorbent is preferably an inorganic porous material that is a solid at room temperature and that supports a metal compound. Supporting refers to a state in which the metal compound is held by the inorganic porous material through physical or chemical adsorption. The inorganic porous material is made of zeolite, sepiolite, aluminum oxide, silica, etc., and has a physical adsorption effect.

[0044] The content of the moisture absorbent is preferably 0.3 parts by mass or more and 3.0 parts by mass or less, more preferably 0.5 parts by mass or more and 2.5 parts by mass or less, and even more preferably 1.0 parts by mass or more and 2.0 parts by mass or less, based on 100 parts by mass of the total polyol.

[0045] (9) Other ingredients The polyurethane foam composition may contain other components other than those described above as necessary. The other components may include additives such as foaming assistants (e.g., zinc stearate, urea-based foaming assistants, etc.), dispersants (e.g., polyethylene-based waxes), crosslinking assistants, pigments, plasticizers, and functional agents (e.g., flame retardants). These additives may be used alone or in combination of two or more.

[0046] 1-2.Physical properties of polyurethane foam (1) Apparent density The apparent density of polyurethane foam (JIS K6401:2011) is 100 kg / m 3 More than 250kg / m 3 Less than 105kg / m 3 More than 200kg / m 3 Less than 110kg / m is preferable. 3 More than 180kg / m 3 Less than 115kg / m is more preferable. 3 More than 130kg / m 3 The following is even more preferred:

[0047] (2) 25% compression hardness (CLD) The 25% compression hardness (CLD (Compression-Load-Deflection)) can be measured based on JIS K6254: 2010. For example, the 25% compression hardness can be measured as follows. The test piece shall be cylindrical with a diameter of 50 mm. There shall be three test pieces. For the measurement, a compression tester shall be used in which the attached compression hardness measuring tool comes into contact with the test piece, and at the same time, the load cell detects the rebound force from the compressed test piece and records it continuously. The test piece is compressed at a rate of 1.0 mm / min until it reaches 30% strain, and the relationship between the compression force and deflection (compression force-deformation curve) is recorded. From the recorded compression force-deformation curve, the compression force at which the deflection is 25% (25% compression force) is determined relative to the thickness of the test piece before compression. The 25% compression load is calculated using the following formula. 25% compressive load [MPa] = 25% compressive force [N] / test piece area [mm 2 ]

[0048] The 25% compression hardness is preferably 0.0005 MPa or more and 0.0025 MPa or less, more preferably 0.0008 MPa or more and 0.0020 MPa or less, and even more preferably 0.0010 MPa or more and 0.0018 MPa or less.

[0049] (3) 40% compression hardness (CLD) The 40% compression hardness can be measured in the same manner as the 25% compression hardness, based on JIS K6254:2010. The test piece is compressed at a rate of 1.0 mm / min until it reaches 50% strain, and the relationship between the compression force and deflection (compression force-deformation curve) is recorded. From the recorded compression force-deformation curve, the compression force at which the deflection is 40% (40% compression force) is determined relative to the thickness of the test piece before compression. The 40% compression load is calculated using the following formula. 40% compressive load [MPa] = 40% compressive force [N] / test piece area [mm 2 ]

[0050] The 40% compression hardness is preferably 0.0008 MPa or more and 0.0045 MPa or less, more preferably 0.0010 MPa or more and 0.0040 MPa or less, and even more preferably 0.0015 MPa or more and 0.0038 MPa or less.

[0051] (4) 50% compression hardness (CLD) The 50% compression hardness can be measured in the same manner as the 25% compression hardness, based on JIS K6254:2010. The test piece is compressed at a rate of 1.0 mm / min until it reaches 60% strain, and the relationship between the compression force and deflection (compression force-deformation curve) is recorded. From the recorded compression force-deformation curve, the compression force at which the deflection is 50% (50% compression force) is determined relative to the thickness of the test piece before compression. The 50% compression load is calculated using the following formula. 50% compressive load [MPa] = 50% compressive force [N] / test piece area [mm 2 ]

[0052] The 50% compression hardness is preferably 0.0020 MPa or more and 0.0080 MPa or less, more preferably 0.0025 MPa or more and 0.0065 MPa or less, and even more preferably 0.0030 MPa or more and 0.0060 MPa or less.

[0053] (5) Compressive set The compression set (JIS K6401:2011) of the polyurethane foam when compressed by 50% is preferably 0% or more and 10.0% or less, more preferably 0.1% or more and 5.0% or less, and even more preferably 0.3% or more and 3% or less.

[0054] (6) Thickness The thickness of the polyurethane foam is preferably 5 mm or less, more preferably 2 mm or less, and even more preferably 1 mm or less.

[0055] 1-3. Manufacturing method of polyurethane foam The polyurethane foam is preferably produced by a general polyurethane foam production method used when the mechanical froth method is adopted. For example, the polyurethane foam composition is charged into a mixing head, and then stirred and mixed to be homogeneous while mixing with an inert gas. The polyurethane foam composition mixed in the mixing head is then heated and cured on a release paper or in a predetermined mold to obtain a polyurethane foam. In order to form a foam of a desired density, the amount of inert gas stirred into the composition is controlled by a gas flow meter. Increasing the amount of cell-forming inert gas decreases the density, and decreasing the amount of inert gas increases the density. As the inert gas, a gas that is a gas under ambient conditions and is substantially inert or does not react at all with any component in the liquid phase may be used as necessary. Examples include nitrogen, carbon dioxide, and dry air, which is a dried normal gas.

[0056] 1-4. Uses of polyurethane foam Polyurethane foam is suitable as a cushioning material. Polyurethane foam is suitable as a cushioning material used in electronic devices and sensor parts. For example, as shown in FIG. 1, a notebook personal computer (PC) 10 includes a polyurethane foam (polyurethane foam 1) of the present disclosure. The polyurethane foam 1 is suitable as a back cushion for a liquid crystal display (LCD) module 12 in the PC 10. Also, as shown in FIG. 2, the PC 10 includes a polyurethane foam (polyurethane foam 2) of the present disclosure. The polyurethane foam 2 is suitable as a packing between the LCD module 12 and a frame 14 in the PC 10.

[0057] The polyurethane foam is also suitable as a cushioning material for use in vehicle-mounted parts, for example, a cushioning material for batteries such as lithium-ion batteries.

[0058] Polyurethane foams can be used for a variety of purposes, including but not limited to cushioning materials, such as electronic device parts for mobile phones, cameras, televisions, etc., vehicle-mounted parts for batteries, vehicle lighting devices, vehicle display devices, etc., waterproof and dustproof sealing materials for toner cartridges, etc.

[0059] 1-5. Effects of the first embodiment In the past, the method of lowering the repulsive stress with the same resin component blend was to lower the density. However, with the conventional resin component blend, the density was 150 kg / m 3 The maximum density reduction was 0.008 MPa, at which point the 50% compression hardness was 0.008 MPa or more. Considering practical performance, the reduction in density was the limit, and even if it was reduced, the cell properties deteriorated.

[0060] The polyurethane foam of the first embodiment has low density and excellent cushioning properties. Since the polyurethane foam contains polymer particles having a core-shell structure (a structure having a core layer containing a rubber component), the nucleating agent effect is easily generated, bubble formation is stabilized, and the density can be reduced. Therefore, the polyurethane foam can be deployed in applications where cushioning properties are required without applying a load to the other side by high compression.

[0061] When the number average molecular weight of the main polyol in the polyurethane foam composition is increased (for example, 5000) and the functionality is increased (for example, 3), the compression set can be reduced.

[0062] When the polyether polyol used in the polyurethane foam composition contains ethylene oxide (EO), the viscosity at the initial stage of the reaction increases, the bubble retention effect improves, and the density can be reduced.

[0063] 2. Polyurethane foam of the second embodiment The polyurethane foam of the second embodiment includes polymer particles having a core-shell structure. The core-shell structure includes a core layer containing a rubber component. The polyurethane foam has a thickness of 5 mm or less. The polyurethane foam has a density of 250 kg / m based on JIS K6401:2011. 3 The following is the result.

[0064] 2-1. Citation of the description of the polyurethane foam of the first embodiment Regarding the polyurethane foam, the explanations in the section "Polyurethane foam of the first embodiment" apply as is to the "Composition for polyurethane foam," "Method of producing polyurethane foam," and "Uses of polyurethane foam," and the description thereof will be omitted. In other words, the explanations in the section "Polyurethane foam of the first embodiment" apply as is to the "Composition for polyurethane foam," "Method of producing polyurethane foam," and "Uses of polyurethane foam."

[0065] 2-2. Physical properties of polyurethane foam of the second embodiment Regarding the physical properties of the polyurethane foam, the explanations in the section "Physical Properties of Polyurethane Foam of First Embodiment" for "25% Compression Hardness (CLD)", "40% Compression Hardness (CLD)", "50% Compression Hardness (CLD)", and "Compression Set" apply as is, and the description is omitted. In other words, the "25% Compression Hardness (CLD)", "40% Compression Hardness (CLD)", "50% Compression Hardness (CLD)", and "Compression Set" explained in the section "Physical Properties of Polyurethane Foam of First Embodiment" apply as is. (1) Apparent density The apparent density of polyurethane foam (JIS K6401:2011) is 250kg / m 3 Less than or equal to 100 kg / m 3 More than 250kg / m 3 Less than 105kg / m is preferable. 3 More than 200kg / m 3 Less than 110kg / m is more preferable. 3 More than 180kg / m 3 More preferably, 115 kg / m 3More than 130kg / m 3 The following are particularly preferred:

[0066] (2) Thickness The polyurethane foam has a thickness of 5 mm or less, preferably 2 mm or less, and more preferably 1 mm or less.

[0067] 2-3. Effects of the second embodiment The polyurethane foam of the second embodiment is low-density, thin, and has excellent cushioning properties. The polyurethane foam contains polymer particles having a core-shell structure (a structure having a core layer containing a rubber component), which makes it easy for the nucleating agent effect to occur, stabilizing bubble formation and allowing for low density. Therefore, the polyurethane foam can be used in applications where cushioning properties are required without applying a load to the other side under high compression.

[0068] 3. Polyurethane foam of the third embodiment The polyurethane foam of the third embodiment includes polymer particles having a core-shell structure. The core-shell structure includes a core layer containing a rubber component. The polyurethane foam has a 25% compression hardness of 0.0025 MPa or less based on JIS K6254:2010.

[0069] 3-1. Citation of the polyurethane foam of the third embodiment Regarding the polyurethane foam, the explanations in the section "Polyurethane foam of the first embodiment" apply as is to the "Composition for polyurethane foam," "Method of producing polyurethane foam," and "Uses of polyurethane foam," and the description thereof will be omitted. In other words, the explanations in the section "Polyurethane foam of the first embodiment" apply as is to the "Composition for polyurethane foam," "Method of producing polyurethane foam," and "Uses of polyurethane foam."

[0070] 3-2. Physical properties of polyurethane foam of the third embodiment Regarding the physical properties of the polyurethane foam, the explanations in the section "Physical Properties of Polyurethane Foam of the First Embodiment" for "40% Compression Hardness (CLD)", "50% Compression Hardness (CLD)", "Compression Set", and "Thickness" apply as is, and the description thereof is omitted. In other words, the explanations in the section "Physical Properties of Polyurethane Foam of the First Embodiment" for "40% Compression Hardness (CLD)", "50% Compression Hardness (CLD)", "Compression Set", and "Thickness" apply as is. (1) Apparent density The apparent density of polyurethane foam (JIS K6401:2011) is 100 kg / m 3 More than 250kg / m 3 Less than 105kg / m is preferable. 3 More than 200kg / m 3 Less than 110kg / m is more preferable. 3 More than 180kg / m 3 More preferably, 115 kg / m 3 More than 130kg / m 3 The following are particularly preferred:

[0071] (2) 25% compression hardness (CLD) The method for measuring the 25% compression hardness (CLD) is the same as in the first embodiment. The 25% compression hardness is 0.0025 MPa or less, preferably 0.0005 MPa or more and 0.0025 MPa or less, more preferably 0.0008 MPa or more and 0.0020 MPa or less, and even more preferably 0.0010 MPa or more and 0.0018 MPa or less.

[0072] 3-3. Effects of the Third Embodiment The polyurethane foam of the third embodiment has excellent cushioning properties. Since the polyurethane foam contains polymer particles having a core-shell structure (a structure having a core layer containing a rubber component), the nucleating agent effect is easily generated, the bubble formation is stabilized, and the density can be reduced. Therefore, the polyurethane foam can be deployed in applications where cushioning properties are required without applying a load to the other side by high compression.

[0073] 4. Polyurethane foam according to the fourth embodiment The polyurethane foam of the fourth embodiment is obtained by a mechanical froth method from a polyurethane foam composition containing a polyol and an isocyanate, and an inert gas. The polyurethane foam composition contains polymer particles having a core-shell structure. The core-shell structure includes a core layer containing a rubber component. The polyurethane foam has a density of 250 kg / m based on JIS K6401:2011. 3 The following is the result.

[0074] 4-1. Citation of the description of the polyurethane foam of the first embodiment Regarding the polyurethane foam, the explanations in the section "Polyurethane foam of the first embodiment" apply as is to the "Composition for polyurethane foam" and "Uses of polyurethane foam", and the description thereof is omitted. In other words, the explanations in the section "Polyurethane foam of the first embodiment" apply as is to the "Composition for polyurethane foam" and "Uses of polyurethane foam".

[0075] 4-2. Properties of polyurethane foam of the fourth embodiment Regarding the physical properties of the polyurethane foam, the explanations in the section "Physical Properties of Polyurethane Foam of First Embodiment" for "25% Compression Hardness (CLD)", "40% Compression Hardness (CLD)", "50% Compression Hardness (CLD)", "Compression Set", and "Thickness" apply as is, and the description thereof is omitted. In other words, the explanations in the section "Physical Properties of Polyurethane Foam of First Embodiment" for "25% Compression Hardness (CLD)", "40% Compression Hardness (CLD)", "50% Compression Hardness (CLD)", "Compression Set", and "Thickness" apply as is. (1) Apparent density The apparent density of polyurethane foam (JIS K6401:2011) is 250kg / m 3 Less than or equal to 100 kg / m 3 More than 250kg / m 3 Less than 105kg / m is preferable. 3 More than 200kg / m 3 Less than 110kg / m is more preferable. 3 More than 180kg / m 3More preferably, 115 kg / m 3 More than 130kg / m 3 The following are particularly preferred:

[0076] 4-3. Manufacturing method of polyurethane foam according to the fourth embodiment The polyurethane foam is obtained by a method similar to the mechanical froth method described in the first embodiment.

[0077] 4-4. Effects of the Fourth Embodiment The polyurethane foam of the fourth embodiment has low density and excellent cushioning properties. Since the polyurethane foam contains polymer particles having a core-shell structure (a structure having a core layer containing a rubber component), the nucleating agent effect is easily generated, bubble formation is stabilized, and the density can be reduced. Therefore, the polyurethane foam can be deployed in applications where cushioning properties are required without applying a load to the other side by high compression. EXAMPLES

[0078] The present invention will be described more specifically below with reference to examples. 1. Preparation of Polyurethane Foam The polyurethane foams of Examples 1-6 and Comparative Examples 1 and 2 were prepared according to the blending ratios shown in Table 1. In Table 1, the blending ratios represent blending ratios (parts by mass) when the total amount of polyol (including polymer particle dispersion) is 100 parts by mass. The thicknesses of the polyurethane foams prepared in Examples 1-6 and Comparative Examples 1 and 2 are shown in Table 1.

[0079] [Table 1]

[0080] Details of the raw materials for the polyurethane foam in Table 1 are shown below. Polyol 1: Polyether polyol, product name: NO.38F (manufactured by Sanyo Chemical Industries, Ltd.), hydroxyl value: 34 mg KOH / g, number of functional groups: 3, number average molecular weight: 5000, EO content: 14% Polyol 2: Polyether polyol, product name: PP-400 (manufactured by Sanyo Chemical Industries, Ltd.), hydroxyl value: 280.5 mg KOH / g, number of functional groups: 2, number average molecular weight: 400 Polyol 3: Polyether polyol, product name: PP-2000 (manufactured by Sanyo Chemical Industries, Ltd.), hydroxyl value: 56.1 mg KOH / g, number of functional groups: 2, number average molecular weight: 2000 Polyol 4: Polyether polyol, product name: EX-914 (AGC), hydroxyl value: 41.9 mg KOH / g, number of functional groups: 3, number average molecular weight: 3000 Polyol 5: Polyether polyol, product name: PR-5007 (ADEKA), hydroxyl value: 23.1 mg KOH / g, number of functional groups: 2, number average molecular weight: 5000 Polymer particle dispersion: MBS resin / polypropylene glycol (molecular weight 400) = 40 / 60 weight ratio, product name: MX-714 (Kaneka Corporation), hydroxyl value: 171.0 mg KOH / g, number of functional groups: 2, number average molecular weight: 400 Polyol 6: Polyester polyol, product name: PLACCEL205U (manufactured by Daicel Corporation), hydroxyl value: 212.0 mgKOH / g, number of functional groups: 2, number average molecular weight: 529 Filler: Aluminum hydroxide, product name: B-325 (manufactured by Nippon Armorix Co., Ltd.) Foam stabilizer: Silicone foam stabilizer, Product name: SZ-1952 (Dow Toray), Hydroxyl value: 40.0 mg KOH / g, Functional group number: 1, Number average molecular weight: 1400 Catalyst: Iron catalyst, Product name: FIN-P1 (manufactured by Nippon Kagaku Sangyo Co., Ltd.), Hydroxyl value: 56.1 mg KOH / g, Number of functional groups: 2, Number average molecular weight: 2000 Antioxidant: Hindered phenol-based antioxidant, product name: SONGNOX 1135LQ (manufactured by SONGWON) Moisture absorbent: Zeolite, product name: Molecular Sieve 3A POWDER (manufactured by Union Showa Co., Ltd.) Isocyanate: Polymeric MDI (crude MDI), product name: Luplanate M5S (manufactured by BASF INOAC Polyurethanes), NCO%: 31.5, number of functional groups: 2.4, number average molecular weight: 320

[0081] 2. Evaluation method (1) Density (apparent density) Density (kg / m 3 ) was measured as the apparent density based on JIS K6401:2011. The measurement results are shown in Table 1.

[0082] (2) 25% compression hardness (CLD) The 25% compression hardness was measured by the method described in the embodiment under a 25% compression load (MPa) at 25° C. The measurement results are shown in Table 1.

[0083] (3) 40% compression hardness (CLD) The 40% compression hardness was measured by the method described in the embodiment under a 40% compression load (MPa) at 25° C. The measurement results are shown in Table 1.

[0084] (4) 50% compression hardness (CLD) The 50% compression hardness was measured by the method described in the embodiment under a 50% compression load (MPa) at 25° C. The measurement results are shown in Table 1.

[0085] (5) Compressive set The compression set at 50% compression was measured based on JIS K6401:2011. The measurement results are shown in Table 1.

[0086] (6) Cellular The cellulosity was evaluated by observing the cross section of the polyurethane foam and based on the following criteria. A: There are relatively small bubbles and no pinholes. B: Relatively large bubbles (pinholes, etc.) are present.

[0087] 3.Results The results are shown in Table 1. The 25% compression hardness of Examples 1-6 was 0.0010 MPa-0.0021 MPa. In contrast, the 25% compression hardness of Comparative Examples 1 and 2 was 0.0040 MPa and 0.0028 MPa, respectively. Examples 1-6 satisfy the following requirement (a). Comparative Examples 1 and 2 do not satisfy the following requirement (a). It is believed that Examples 1-6 were able to reduce the 25% compression hardness by satisfying the following requirement (a). Requirement (a): The polyurethane foam contains polymer particles having a core-shell structure with a core layer containing a rubber component.

[0088] The 40% compression hardness of Examples 1-6 was 0.0017MPa-0.0037MPa. In contrast, the 40% compression hardness of Comparative Examples 1 and 2 was 0.0060MPa and 0.0048MPa, respectively. It is believed that Examples 1-6 were able to reduce the 40% compression hardness by satisfying the above requirement (a).

[0089] The 50% compression hardness of Examples 1-6 was 0.0030MPa-0.0067MPa. In contrast, the 50% compression hardness of Comparative Examples 1 and 2 was 0.0083MPa and 0.0069MPa, respectively. It is believed that Examples 1-6 were able to reduce the 50% compression hardness by satisfying the above requirement (a).

[0090] 4. Effects of the embodiment According to the above examples, a polyurethane foam having a thin shape, low density, and excellent cushioning properties that does not easily apply a load to the other side when compressed could be produced. In particular, a polyurethane foam that does not easily apply a load to the other side when highly compressed could be produced.

[0091] The present disclosure is not limited to the above-described embodiments, and various modifications and variations are possible. [Explanation of symbols]

[0092] 1,2: Polyurethane foam 10: Personal computers (electronic devices) 12: LCD module 14: Frame

Claims

1. The polymer particles have a core-shell structure with a core layer containing a rubber component, Density based on JIS K6401:2011 is 100 kg / m ３ More than 250kg / m ３ Below is a polyurethane foam.

2. The polyurethane foam according to claim 1, having a 50% compression hardness based on JIS K6254:2010 of 0.0080 MPa or less.

3. An electronic device comprising the polyurethane foam according to claim 1 or 2.

Images