Resin foam, method for producing resin foam, and method for producing pulverized product of resin foam

Abstract

To construct a new application in which a resin foam pulverized product can be suitably used, and to provide a new technique for producing a resin foam pulverized product suitable for the application.SOLUTION: The present technology provides a resin foam containing a pulverized resin foam product obtained by pulverizing a cooled resin foam. The present technology also provides a method for producing a resin foam, including a production step of producing a resin foam using, as a raw material, a pulverized product of a resin foam obtained by pulverizing a cooled resin foam. The present technology further provides a method for producing a pulverized product of a resin foam, the method including a pulverization step of pulverizing the resin foam cooled using a solid cooling agent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present technology relates to a resin foam. More specifically, the present technology relates to a resin foam containing pulverized resin foam, a method for producing a resin foam, and a method for producing pulverized resin foam. [Background technology]

[0002] Pulverized resin foam has been used in various fields. For example, Patent Document 1 proposes a technique for using cut pieces of porous polyurethane resin as an adsorbent for recovering fat-soluble secondary metabolites produced by plant cells.

[0003] Technologies related to methods for pulverizing resin foams that can be used for such a variety of applications are also being developed. For example, Patent Document 2 proposes a technology for efficiently and inexpensively producing thermoplastic resin powder from thermoplastic resins with good elongation, in which thermoplastic resin foams with an average cell diameter of 100 μm to 600 μm are freeze-pulverized to produce powder with an average particle size of 100 μm to 150 μm. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-223202 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-203919 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, pulverized resin foam is used for various purposes in various fields, and pulverization techniques are also being developed. Therefore, the main objective of the present technology is to establish new applications in which pulverized resin foam can be suitably used, and to provide a new technology for producing pulverized resin foam suitable for such applications. [Means for solving the problem]

[0006] The inventors of the present application conducted intensive research to solve the above-mentioned problems, and succeeded in producing high-quality resin foam by performing material recycling using the resin foam pulverization obtained by pulverizing cooled resin foam, thereby completing the present technology.

[0007] That is, in the present technology, first, a resin foam is provided, which includes a pulverized resin foam obtained by pulverizing a cooled resin foam.

[0008] The present technology also includes a manufacturing step of manufacturing a resin foam using, as a raw material, a pulverized resin foam obtained by pulverizing the cooled resin foam; The present invention provides a method for producing a resin foam, comprising:

[0009] The present technology further provides a method for producing pulverized resin foam, which includes a pulverization step of pulverizing a resin foam cooled using a solid coolant. In the pulverization step in the method for producing pulverized resin foam according to the present technology, the resin foam can be pulverized together with the coolant. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a photograph showing the cross sections of the resin foams of Example 1 and Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0011] A preferred embodiment for carrying out the present technology will be described below. The embodiments described below are examples of typical embodiments of the present technology, and any of the embodiments can be combined. Furthermore, the scope of the present technology is not to be interpreted as being narrow.

[0012] 1.Resin foam The resin foam according to the present technology is characterized by containing a specific pulverized resin foam. The type of resin foam is not particularly limited as long as the resin foam according to the present technology contains the specific pulverized resin foam. Examples of the resin foam include polyurethane foam, polyethylene foam, polypropylene foam, vinyl chloride foam, polystyrene foam, and phenol foam. In the present technology, polyurethane foam is particularly preferred among these.

[0013] When the type of resin foam according to the present technology is polyurethane foam, it can be produced using, as raw materials, a composition for producing polyurethane foam, which contains, in addition to a specific pulverized resin foam, a polyol, a blowing agent, a catalyst, a foam stabilizer, an antioxidant, an isocyanate, and, as necessary, various additives, etc. Hereinafter, each raw material when the type of resin foam according to the present technology is polyurethane foam will be described.

[0014] (1) Crushed resin foam The pulverized resin foam material that can be used as a raw material for the resin foam according to the present technology is characterized in that it is obtained by pulverizing a cooled resin foam. Details of the pulverization method are the same as those that can be used in the pulverization step in the manufacturing method for pulverized resin foam according to the present technology described below, and therefore will not be described here.

[0015] The cooling method for the resin foam (hereinafter also referred to as "resin foam to be pulverized") used as the raw material for the pulverized material is not particularly limited, and one or a combination of two or more common cooling methods can be used. Examples include a method of cooling using a solid or liquid coolant, and a method of cooling for a predetermined period of time in a refrigerator or freezer. Among these, in the present technology, a method of cooling using a solid coolant is preferred. Note that details of the solid coolant are the same as those used in the method for producing pulverized resin foam according to the present technology described below, and therefore will not be described here.

[0016] The type of resin foam to be pulverized can be one or a combination of two or more common resin foams, as long as the action and effect of the present technology are not impaired. Examples of resin foams to be pulverized include polyurethane foam, polyethylene foam, polypropylene foam, vinyl chloride foam, polystyrene foam, and phenol foam. However, it is preferable to use a resin foam of the same type as the resin foam containing pulverized resin foam as the resin foam to be pulverized. For example, when producing polyurethane foam containing pulverized resin foam, it is preferable to select polyurethane foam as the resin foam to be pulverized.

[0017] The physical properties of the resin foam to be pulverized are not particularly limited as long as they do not impair the action and effect of the present technology, and a resin foam with appropriate physical properties can be selected as the resin foam to be pulverized depending on the cooling method, pulverization method, the application and expected physical properties of the resin foam to be produced, etc.

[0018] In the present technology, the glass transition point (Tg) of the resin foam to be pulverized is preferably -50°C or higher, more preferably -30°C or higher, even more preferably 0°C or higher, and particularly preferably 10°C or higher. By using a resin foam with a glass transition point within this range as the resin foam to be pulverized, pulverization can be performed more easily. There is no particular upper limit to the glass transition point (Tg) of the resin foam to be pulverized, and the resin foam to be pulverized may be, for example, a resin foam having a glass transition point (Tg) of 30°C or lower, 25°C or lower, or the like.

[0019] The content of pulverized resin foam in the resin foam can be freely set as long as it does not impair the function and effect of the present technology. The lower limit of the content of pulverized resin foam in the resin foam can be set to, for example, 1 part by mass or more, preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and even more preferably 7 parts by mass or more, per 100 parts by mass of the polyol used. The present technology is characterized in that even if a predetermined amount of pulverized resin foam is contained, as described below, it has physical properties equivalent to or better than those of a resin foam produced without using pulverized resin foam.

[0020] The upper limit of the content of pulverized resin foam in the resin foam can be set to, for example, 30 parts by mass or less, preferably 25 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less, per 100 parts by mass of the polyol used. By setting the content of pulverized resin foam in the resin foam within this range, deterioration in the physical properties of the resin foam can be suppressed.

[0021] (2) Polyol The polyol that can be used in the present technology can be one or more polyols that can be used in the production of general polyurethane foams, as long as the action and effect of the present technology are not impaired. Specific examples include polyether polyols obtained by adding alkylene oxides such as ethylene oxide (EO) and propylene oxide (PO) to polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, glycerin, pentaerythritol, trimethylolpropane, sorbitol, and sucrose; polyester polyols obtained by polycondensation of aliphatic carboxylic acids such as malonic acid, succinic acid, and adipic acid, or aromatic carboxylic acids such as phthalic acid, with aliphatic glycols such as ethylene glycol, diethylene glycol, and propylene glycol; polyether ester polyols obtained by reacting the above polyether polyols with polybasic acids to form polyesters; and polyether ester polyols having both polyether and polyester segments in one molecule.

[0022] (3) Foaming agent The blowing agent that can be used in the present technology can be freely selected from one or more blowing agents that can be used in the production of polyurethane foams, as long as it does not impair the functions and effects of the present technology. Specific examples include water, hydrocarbons, halogenated compounds, etc. Examples of hydrocarbons include cyclopentane, isopentane, and normal pentane. Examples of the halogenated compounds include methylene chloride, trichlorofluoromethane, dichlorodifluoromethane, nonafluorobutyl methyl ether, nonafluorobutyl ethyl ether, pentafluoroethyl methyl ether, and heptafluoroisopropyl methyl ether. Among these, water is preferably used as the blowing agent in the present technology. The water may be ion-exchanged water, tap water, distilled water, or the like. The amount of the blowing agent used is not particularly limited as long as it does not impair the functions and effects of the present technology. For example, 1 to 8 parts by mass of the blowing agent can be used per 100 parts by mass of polyol.

[0023] (4) Catalyst The catalyst that can be used in the present technology can be one or more catalysts that can be used in the production of polyurethane foams, and can be freely selected and used as long as it does not impair the functions and effects of the present technology. Specific examples include amine-based catalysts such as triethylamine, dimethylaminohexanol, triethylenediamine, and tetramethylguanidine; tin-based catalysts such as dibutyltin dilaurate; and metal catalysts (also referred to as "organometallic catalysts") such as phenylmercury propionate and lead octenate. The amount of catalyst used is not particularly limited as long as it does not impair the functions and effects of the present technology. For example, 0.1 to 2 parts by mass of catalyst can be used per 100 parts by mass of polyol.

[0024] (5) Foam stabilizer The foam stabilizer that can be used in the present technology can be freely selected from one or more foam stabilizers that can be used in the production of polyurethane foam, as long as the action and effect of the present technology are not impaired. Specific examples include silicone-based foam stabilizers, fluorine-containing compound-based foam stabilizers, surfactants, etc. The amount of foam stabilizer used is not particularly limited as long as the action and effect of the present technology are not impaired. For example, 0.5 to 3 parts by mass of foam stabilizer can be used per 100 parts by mass of polyol.

[0025] (6) Antioxidants The antioxidant that can be used in the present technology can be one or more antioxidants that can be used in the production of polyurethane foam, as long as the action and effect of the present technology are not impaired. Specific examples include phenol-based antioxidants (monophenol-based, thiobisphenol-based, hindered phenol-based), naphthylamine-based, diphenylamine-based, p-phenyldiamine-based, quinoline-based, hydroquinone derivatives, and phosphite-based antioxidants. The amount of antioxidant used is not particularly limited as long as the action and effect of the present technology are not impaired. For example, 0.5 to 3 parts by mass of antioxidant can be used per 100 parts by mass of polyol.

[0026] (7) Isocyanate The isocyanate that can be used in the present technology can be one or more isocyanates that can be used in the production of polyurethane foams, as long as the action and effect of the present technology are not impaired. Specific examples include aliphatic isocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexamethane diisocyanate; aromatic isocyanates such as toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthalene diisocyanate, xylylene diisocyanate, and polymeric polyisocyanate (crude MDI); and modified polyisocyanates obtained by modifying these.

[0027] The isocyanate index of the polyurethane foam is not particularly limited as long as it does not impair the functions and effects of the present technology, and can be set, for example, to a value of 90 to 120. In the present technology, the isocyanate index is a value calculated by [(isocyanate equivalent in the composition for producing polyurethane foam / active hydrogen equivalent in the composition for producing polyurethane foam) × 100].

[0028] (8) Other In the present technology, one or more additives that can be used in the production of polyurethane foams can be freely selected and used as needed, as long as they do not impair the functions and effects of the present technology. Specific examples include flame retardants, stabilizers, plasticizers, colorants, pigments, crosslinking agents, antibacterial agents, dispersants, and ultraviolet absorbers.

[0029] 2. Physical properties of resin foam (1) Density The density of the resin foam according to the present technology can be freely set as long as it does not impair the functions and effects of the present technology. The lower limit of the density of the resin foam according to the present technology is, for example, 15 kg / m 3 or more, preferably 17 kg / m 3 More preferably, 20 kg / m 3 More preferably, 23 kg / m 3 The upper limit of the density of the resin foam according to the present technology is, for example, 45 kg / m 3 Less than 40 kg / m 3 Less than or equal to 35 kg / m 3 More preferably, 30 kg / m or less 3 By setting the density of the resin foam within this range, it is possible to impart cushioning properties without impairing the flexibility of the resin foam (preventing it from becoming hard). Note that in the present technology, the density is a value measured by the method described in the examples below.

[0030] (2) 25% compression hardness The 25% compression hardness of the resin foam according to the present technology can be freely set as long as it does not impair the functions and effects of the present technology. The lower limit of the 25% compression hardness of the resin foam according to the present technology is, for example, 95 N or more, preferably 100 N or more, more preferably 105 N or more, and even more preferably 110 N or more. The upper limit of the 25% compression hardness of the resin foam according to the present technology is, for example, 160 N or less, preferably 150 N or less, more preferably 130 N or less, and even more preferably 120 N or less. By setting the 25% compression hardness of the resin foam within this range, the resin foam according to the present technology can be suitably used in applications requiring softness. Note that, in the present technology, the 25% compression hardness is a value measured by the method described in the Examples described below.

[0031] (3) Rebound elasticity The rebound resilience of the resin foam according to the present technology can be freely set as long as it does not impair the functions and effects of the present technology. The lower limit of the rebound resilience of the resin foam according to the present technology is, for example, 20% or more, preferably 25% or more, and more preferably 30% or more. The upper limit of the rebound resilience of the resin foam according to the present technology is, for example, 55% or less, preferably 50% or less, and more preferably 45% or less. In the present technology, the rebound resilience is a value measured by the method described in the Examples below.

[0032] (4) Tensile strength The tensile strength of the resin foam according to the present technology can be freely set as long as it does not impair the functions and effects of the present technology. The lower limit of the tensile strength of the resin foam according to the present technology is, for example, 80 kPa or more, preferably 85 kPa or more, and more preferably 90 kPa or more. The upper limit of the tensile strength of the resin foam according to the present technology is, for example, 110 kPa or less, preferably 105 kPa or less, and more preferably 100 kPa or less. In the present technology, the tensile strength is a value measured by the method described in the examples below.

[0033] (5) Growth rate The elongation percentage of the resin foam according to the present technology can be freely set as long as it does not impair the functions and effects of the present technology. The lower limit of the elongation percentage of the resin foam according to the present technology is, for example, 120% or more, preferably 125% or more, and more preferably 130% or more. The upper limit of the elongation percentage of the resin foam according to the present technology is, for example, 160% or less, preferably 155% or less, and more preferably 150% or less. In the present technology, the elongation percentage is a value measured by the method described in the examples below.

[0034] (6) Tear strength The tear strength of the resin foam according to the present technology can be freely set as long as it does not impair the function and effect of the present technology. The lower limit of the tear strength of the resin foam according to the present technology is, for example, 4.0 N / cm or more, preferably 4.5 N / cm or more, and more preferably 5.0 N / cm or more. The upper limit of the tear strength of the resin foam according to the present technology is, for example, 20.0 N / cm or less, preferably 15.0 N / cm or less, and more preferably 10.0 N / cm or less. In the present technology, the tear strength is a value measured by the method described in the examples described below.

[0035] (7)Dry heat distortion The dry heat distortion of the resin foam according to the present technology can be freely set as long as it does not impair the function and effect of the present technology. The lower limit of the dry heat distortion of the resin foam according to the present technology is the lower the better, for example, 0%. The upper limit of the dry heat distortion of the resin foam according to the present technology is, for example, 3.0% or less, preferably 2.5% or less, and more preferably 2.0% or less. In the present technology, the dry heat distortion is a value measured using the method described in the examples below.

[0036] (8) Breathability The breathability of the resin foam according to the present technology can be freely set as long as it does not impair the functions and effects of the present technology. The lower limit of the breathability of the resin foam according to the present technology, measured by a method in accordance with ASTM D 3574, is, for example, 100 L / min or more, preferably 110 L / min or more, more preferably 120 L / min or more, even more preferably 130 L / min or more, and still more preferably 140 L / min or more. The upper limit of the breathability of the resin foam according to the present technology, measured by a method in accordance with ASTM D 3574, is, for example, 200 L / min or less, preferably 190 L / min or less, and more preferably 180 L / min or less.

[0037] In addition, the lower limit of the air permeability of the resin foam according to the present technology measured by a method conforming to JIS K 6400-7 is, for example, 100 cm 3 / cm 2 s or more, preferably 110cm 3 / cm 2 s or more, preferably 120 cm 3 / cm 2 s or more, more preferably 130 cm 3 / cm 2 s or more, even more preferably 140 cm 3 / cm 2 The upper limit of the air permeability of the resin foam according to the present technology measured by a method conforming to JIS K 6400-7 is, for example, 200 cm 3 / cm 2 s or less, preferably 190 cm 3 / cm 2 s or less, preferably 180 cm 3 / cm 2 ·s or less.

[0038] By setting the breathability of the resin foam within this range, the resin foam according to the present technology can be suitably used for applications requiring breathability (for example, bedding such as mattresses and pillows).

[0039] (9) Number of cells The cell number of the resin foam according to the present technology can be freely set as long as it does not impair the function and effect of the present technology. The lower limit of the cell number of the resin foam according to the present technology is, for example, 20 cells / 25 mm or more, preferably 25 cells / 25 mm or more, and more preferably 30 cells / 25 mm or more. The upper limit of the cell number of the resin foam according to the present technology is, for example, 50 cells / 25 mm or less, preferably 45 cells / 25 mm or less, and more preferably 40 cells / 25 mm or less. In the present technology, the cell number is a value measured by the method described in the Examples below.

[0040] 3. Manufacturing method for crushed resin foam The method for producing pulverized resin foam according to the present technology is a method that includes at least a specific pulverization step. Furthermore, the method for producing pulverized resin foam according to the present technology may also include other steps, such as a classification step and a coolant removal step, as needed. Each step will be described in detail below.

[0041] (1) Crushing process The pulverization step is a step of pulverizing the cooled resin foam. A solid coolant is used to cool the resin foam. The pulverization method used in the pulverization step is not particularly limited as long as it does not impair the functions and effects of the present technology, and one or more general pulverization methods can be freely combined and used. Examples include a method of pulverizing using a hammer or other hitting tool, and a method of pulverizing using a pulverizer such as a cutter mill or hammer mill. The details of the resin foam to be pulverized are the same as those of the resin foam to be pulverized described above, and therefore will not be described here.

[0042] The solid cooling agent used in the present technology is preferably a cooling agent that can exist as a solid under normal pressure, such as dry ice or ice.

[0043] Furthermore, the solid coolant used in this technology is preferably a coolant that sublimes under normal pressure and temperature. Examples of coolants that sublimate under normal pressure and temperature include dry ice. By using a coolant that sublimes under normal pressure and temperature, the coolant disappears from the pulverized material by sublimation during or after the pulverization process. This makes it possible to omit the coolant removal process described below, thereby simplifying the manufacturing process and contributing to reducing manufacturing time and costs. In other words, the pulverized resin foam product according to this technology can be a pulverized resin foam product in which the coolant has been sublimated and removed from a pulverized mixture of resin foam and a solid coolant.

[0044] In the crushing process, the resin foam to be crushed may be crushed together with a solid coolant. Conventional resin foam crushing techniques mainly involve freezing the resin foam to be crushed in advance and then crushing the frozen resin foam. In contrast, the present technology has succeeded in producing crushed resin foam by simply crushing the resin foam to be crushed together with a solid coolant without pre-freezing it. In other words, the present technology can omit the freezing process of freezing the resin foam to be crushed before crushing, thereby simplifying the manufacturing process and contributing to reducing manufacturing time and costs.

[0045] In the crushing process, the size of the resin foam to be crushed is not particularly limited. In conventional resin foam crushing techniques, the resin foam to be crushed is primarily frozen in advance and then crushed in its frozen state. Therefore, in order to achieve efficient freezing, it is desirable to preliminarily reduce the size of the resin foam to be crushed to a certain extent. In contrast, in the present technology, by crushing the resin foam together with a solid coolant, it is possible to crush the resin foam while it remains in large chunks, as shown in the examples described below.

[0046] The solid coolant used in the pulverization step preferably has a sublimation point in a temperature range below the glass transition point of the resin foam to be pulverized, preferably below −20° C. from the glass transition point, more preferably below −30° C. from the glass transition point, even more preferably below −40° C. from the glass transition point, and even more preferably below −50° C. from the glass transition point. By using a solid coolant having a sublimation point in such a range, the resin foam to be pulverized can be pulverized more efficiently.

[0047] The size of the solid coolant used in the grinding process is not particularly limited as long as it does not impair the function and effect of the present technology. The lower limit of the size of the coolant is, for example, 0.01 cm 3 More than 0.05cm, preferably 3 More than 0.1cm, preferably 0.1cm 3 By using a coolant having a size within this range, for example, in the case of a sublimable coolant, it is possible to prevent premature sublimation, and more reliably cool the resin foam to be pulverized. In addition, the upper limit of the size of the coolant is, for example, 5 cm. 3 Less than 3cm, preferably 3 Less than 1cm, preferably 1cm 3 By using a coolant having a size within this range, the resin foam to be pulverized can be cooled more efficiently.

[0048] The amount of solid coolant used in the pulverization step is not particularly limited as long as it does not impair the function and effect of the present technology. The lower limit of the amount of coolant used is, for example, 100 parts by mass or more, preferably 300 parts by mass or more, and more preferably 500 parts by mass or more, relative to 100 parts by mass of the resin foam to be pulverized. By setting the amount of coolant used within this range, the resin foam to be pulverized can be cooled more efficiently. The upper limit of the amount of coolant used is, for example, 5,000 parts by mass or less, preferably 4,000 parts by mass or less, and more preferably 3,000 parts by mass or less, relative to 100 parts by mass of the resin foam to be pulverized. By setting the amount of coolant used within this range, for example, in the case of a sublimable coolant, it can be rapidly sublimated during or after pulverization of the resin foam to be pulverized. As a result, it is possible to omit the coolant removal step described below, which simplifies the manufacturing process and contributes to reducing manufacturing time and costs.

[0049] (2) Classification process The classification step is a step of classifying the pulverized resin foam obtained through the pulverization step based on its size. Although the classification step is not an essential step in the method for producing pulverized resin foam according to the present technology, the classification step makes it possible to make the pulverized resin foam uniform in size, and therefore the method can be suitably used for various applications.

[0050] The classification method in the classification step is not particularly limited, and one or a combination of two or more methods that can be used to classify pulverized materials can be used. For example, a classification method using a classification tool such as a sieve can be used.

[0051] The size of the pulverized resin foam after the classification step can be appropriately set depending on the intended use, etc. For example, when the pulverized resin foam is used as a raw material for a resin foam, the upper limit of the particle size of the pulverized resin foam can be set to, for example, 4 mm or less, preferably 3 mm or less, and more preferably 2 mm or less. Setting the upper limit of the particle size of the pulverized resin foam within this range can improve the quality of the resin foam produced using it. Furthermore, the lower limit of the particle size of the pulverized resin foam is, for example, 0.1 mm or more, preferably 0.2 mm or more, and more preferably 0.3 mm or more. Setting the lower limit of the particle size of the pulverized resin foam within this range can prevent the pulverized resin foam from scattering during resin foam production, allowing for more efficient resin foam production.

[0052] (3) Coolant removal process The coolant removal step is a step of removing the solid coolant from the pulverized resin foam obtained through the pulverization step. In the method for producing pulverized resin foam according to the present technology, this coolant removal step is not an essential step. For example, as described above, by using a sublimable coolant, the solid coolant can be removed from the pulverized resin foam without performing the coolant removal step.

[0053] When a coolant removal step is performed, the removal method in the coolant removal step is not particularly limited, and any method can be adopted depending on the properties of the coolant used. For example, when a sublimable coolant is used, the coolant can be removed from the pulverized resin foam by simply leaving it for a certain period of time. Furthermore, when a vaporizable coolant is used, the coolant can also be removed from the pulverized resin foam by drying the pulverized resin foam after the pulverization step. Furthermore, the coolant can also be removed from the pulverized resin foam by a method such as immersing the pulverized resin foam after the pulverization step in a solvent in which the coolant is soluble. When a solvent is used, a drying step may be further performed to evaporate the solvent.

[0054] 4. Manufacturing method of resin foam The method for producing a resin foam according to the present technology is a method for producing a resin foam using pulverized resin foam obtained by pulverizing a cooled resin foam as a raw material. The cooling method for the resin foam to be pulverized is the same as the cooling method described for the resin foam according to the present technology described above, and therefore a description thereof will be omitted here. Furthermore, the pulverization method for the cooled resin foam is the same as the pulverization method that can be used in the pulverization step in the method for producing pulverized resin foam according to the present technology described above, and therefore a description thereof will be omitted here. Furthermore, steps that can be performed other than the pulverization step for the pulverized resin foam are the same as the other steps that can be performed in the method for producing pulverized resin foam according to the present technology described above, and therefore a description thereof will be omitted here.

[0055] The production of the pulverized resin foam and the production of the resin foam using the pulverized resin foam as a raw material may be carried out by the same organization or by different organizations. For example, one organization may produce the pulverized resin foam, and another organization may use the produced pulverized resin foam to produce the resin foam.

[0056] The method for producing a resin foam using the pulverized resin foam as a raw material can be any general method for producing a resin foam, and can be any combination thereof, as long as the action and effect of the present technology are not impaired. Specifically, the resin foam can be produced by mixing the components of the composition for producing the resin foam described above to prepare a composition, and then allowing a resinification reaction and a foaming reaction to proceed.

[0057] The foaming method for producing a resin foam according to the present technology can employ any of slab foaming, batch foaming, and mold foaming. Slab foaming is a method in which a resin foam production composition (raw material for resin foam) is mixed and discharged onto a moving conveyor, and foamed at atmospheric pressure and room temperature. Batch foaming is a method in which a mixed resin foam production composition is discharged into a foaming box, and foamed at atmospheric pressure and room temperature. Mold foaming is a method in which a resin foam production composition is mixed and injected into the cavity of a mold (forming die), and foamed to the shape of the cavity. [Example]

[0058] The present technology will be described in more detail below based on examples. Note that the examples described below are examples of typical examples of the present technology, and the scope of the present technology should not be construed as being narrow.

[0059] (1) Manufacturing of crushed resin foam As an example of a resin foam, a low-resilience soft polyurethane foam (glass transition temperature (Tg): 17.5°C, density: 40 kg / m) measuring 100 mm x 100 mm x 50 mm was used. 3 ) and 400 g of dry ice as an example of a coolant were placed in a polyethylene bag, and the bag was hit from the outside with a hammer to pulverize the contents. After the dry ice sublimated, the pulverized polyurethane foam was sieved through a 2 mm mesh sieve to obtain pulverized resin foam (polyurethane powder) with a size of less than 2 mm.

[0060] (2) Manufacturing of resin foam [Example 1] The polyol, blowing agent, catalysts 1 and 2, foam stabilizer, antioxidants 1 and 2, and crushed resin foam shown in Table 1 below were mixed, and then isocyanate was added to form a raw material mixture, which was then poured into a non-sealed 270 mm square foaming box with an open top and foamed. After foaming, the foaming box containing the foam was placed in a thermostatic bath at 70°C to cure, yielding a resin foam (polyurethane foam).

[0061] [Comparative Example 1] A resin foam was produced in the same manner as in Example 1, except that the pulverized resin foam was not used.

[0062] (3) Evaluation The produced resin foams were evaluated as follows: In addition, the cross sections of the resin foams of Example 1 and Comparative Example 1 were photographed.

[0063] [density] The density was measured by a method in accordance with JIS K 7222:2005.

[0064] [25% compression hardness] The 25% compression hardness was measured using a method in accordance with JIS K 6400-2:2012.

[0065] [Rebound elasticity] The rebound resilience was measured by a method in accordance with JIS K 6400-3:2011.

[0066] [Tensile strength] The tensile strength was measured by a method in accordance with JIS K 6400-5:2012.

[0067] [Elongation rate] The elongation was measured by a method in accordance with JIS K 6400-5:2012.

[0068] [Tear strength] The tear strength was measured according to the method of JIS K 6400-5:2012.

[0069] [Dry heat distortion] Dry heat distortion was measured using a method in accordance with JIS K 6400-4:2004.

[0070] [Breathability] The breathability was measured according to methods in accordance with ASTM D 3574 and JIS K 6400-7.

[0071] Number of Cells The number of cells was measured by a method in accordance with JIS K 6400-1:2004.

[0072] (4) Results The results are shown in Table 1 and FIG.

[0073] [Table 1]

[0074] (5) Discussion 1, the foam raw material according to the present technology, which includes the pulverized resin foam obtained by pulverizing the cooled resin foam, has physical properties equal to or better than those of Comparative Example 1, which was produced without using the pulverized resin foam. In particular, Example 1 had improved breathability compared to Comparative Example 1.

Claims

1. A resin foam comprising a pulverized resin foam obtained by pulverizing a cooled resin foam.

2. a manufacturing step of producing a resin foam using the resin foam pulverized product obtained by pulverizing the cooled resin foam as a raw material; A method for producing a resin foam, comprising:

3. A method for producing pulverized resin foam, comprising a pulverization step of pulverizing a resin foam cooled using a solid coolant.

4. The method for producing pulverized resin foam according to claim 3 , wherein the pulverizing step pulverizes the resin foam together with the coolant.

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