Polyurethane foam molded body

Abstract

To provide a polyurethane foam molded body capable of improving damping performance.SOLUTION: A polyurethane foam molded body is obtainable from a composition including polyol, polyisocyanate, an alkyl ester having a structure derived from fatty acid ester or benzene propanoic acid. A coefficient of variation obtained by dividing a standard deviation of a cell diameter by an average cell diameter is 0.37 or more.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This disclosure relates to a polyurethane foam molded article. [Background technology]

[0002] The molded article disclosed in Patent Document 1 is made of foamed urethane. This molded article has a plurality of cavities (cells). The plurality of cavities are dispersed and arranged inside the molded article. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2021 / 200870 [Overview of the project] [Problems that the invention aims to solve]

[0004] When a molded body, such as the one described in Patent Document 1, is made into a thin-walled form, its vibration damping properties decrease. Furthermore, if the cells of the molded body become coarser, the air permeability increases, further reducing vibration damping properties. Therefore, there is a need for a configuration that can improve the vibration damping properties of the molded body. This disclosure aims to provide a polyurethane foam molded article that can improve vibration damping. This disclosure can be realized in the following forms. [Means for solving the problem]

[0005] [1] A polyurethane foam molded article obtained from a composition containing a polyol, a polyisocyanate, and an alkyl ester having a structure derived from a fatty acid ester or benzenepropanoic acid, A polyurethane foam molded article having a coefficient of variation of 0.37 or greater, obtained by dividing the standard deviation of cell diameter by the mean cell diameter. [2] A polyurethane foam molded article obtained from a composition containing a polyol, a polyisocyanate, and a fatty acid ester or an alkyl ester having a structure derived from benzenepropanoic acid, which is having an average cell diameter of 400 μm or more, and having a standard deviation of cell diameter of 200 μm or more, the polyurethane foam molded article. [Effects of the Invention]

[0006] According to the present disclosure, a polyurethane foam molded article with improved vibration damping properties can be provided. [Brief Description of the Drawings]

[0007] [Figure 1] FIG. 2 is a perspective view schematically showing a vehicle floor silencer using a polyurethane foam molded article according to one embodiment. [Figure 2] FIG. 2 is an explanatory view schematically showing an insulator arranged around an engine and a motor, which uses a polyurethane foam molded article. [Figure 3] FIG. 2 is a cross-sectional view schematically showing an example of the internal structure of the polyurethane foam molded article of Example 1. [Figure 4] FIG. 2 is an explanatory view for explaining a method of measuring a cell diameter in cells appearing on a horizontal plane photographed with an optical microscope. [Modes for Carrying Out the Invention]

[0008] Here, desirable examples of the present disclosure are shown. [3] The polyurethane foam molded article according to [1] or [2], wherein the loss factor at an antiresonance point of 450 Hz or more and 550 Hz or less measured in accordance with JIS K 7391:2008 is 0.330 or more, and / or the loss factor at an antiresonance point of 1950 Hz or more and 2200 Hz or less is 0.130 or more. [4] A polyurethane foam molded article according to any one of [1] to [3], wherein the loss coefficient at the anti-resonance point between 1100 Hz and 1300 Hz, measured in accordance with JIS K 7391:2008, is 0.090 or higher. [5] A vibration damping member, a polyurethane foam molded body as described in any of [1] to [4].

[0009] The disclosure is described in detail below. In this specification, when a numerical range is indicated using "-", it includes both the lower and upper limits unless otherwise specified. For example, the expression "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".

[0010] 1. Polyurethane foam molded body The polyurethane foam molded article is obtained from a composition containing a polyol, a polyisocyanate, and an alkyl ester having a structure derived from a fatty acid ester or benzenepropanoic acid.

[0011] (1.1) Polyol The polyol is not particularly limited. Various polyols may be used individually or in combination of two or more. The polyol may be an ether-based polyol or an ester-based polyol. Furthermore, one of these polyols may be used as the starting material, or two or more may be used in combination.

[0012] Examples of ether-based polyols include polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, glycerin, pentaerythritol, trimethylolpropane, sorbitol, and sucrose, as well as polyether polyols obtained by adding alkylene oxides such as ethylene oxide and propylene oxide to polyhydric alcohols.

[0013] Examples of ester polyols include polyester polyols and phthalic acid ester 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.

[0014] The number-average molecular weight of the polyol is not particularly limited. Preferably, it is 500-10000, more preferably 1000-6000, and even more preferably 2000-5000. The number-average molecular weight of the polyol can be measured by gel permeation chromatography (GPC).

[0015] (1.2) Polyisocyanates The polyisocyanate is not particularly limited. As polyisocyanates, aliphatic or aromatic polyisocyanates having two or more isocyanate groups, mixtures thereof, and modified polyisocyanates obtained by modifying them can be used. Examples of aliphatic polyisocyanates include hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexamethane diisocyanate. Examples of aromatic polyisocyanates include toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymeric polyisocyanate (crude MDI), modified MDI, naphthalene diisocyanate, and xylylene diisocyanate. Other prepolymers can also be used.

[0016] Furthermore, the polyisocyanate may be a bifunctional isocyanate having two isocyanate groups in one molecule, or a trifunctional or more isocyanate having three or more isocyanate groups in one molecule. In addition, one of these isocyanates may be used as the starting material, or two or more may be used in combination.

[0017] Examples of bifunctional aromatic polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 2,2'-diphenylmethane diisocyanate (2,2'-MDI), xylylene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, and mixtures thereof.

[0018] Examples of bifunctional alicyclic polyisocyanates include cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, and methylcyclohexane diisocyanate.

[0019] Examples of bifunctional aliphatic polyisocyanates include butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropyl diisocyanate, methylene diisocyanate, and lysine isocyanate. Examples of isocyanates with two or more functions include polymeric MDIs and isocyanates with three or more functions.

[0020] The NCO index in the composition is preferably 70-110, and more preferably 80-105. The NCO index is defined as the value obtained by dividing the total number of isocyanate groups in the polyisocyanate by the total number of active hydrogens that react with the isocyanate groups, and multiplying the result by 100. That is, the NCO index is 100 when the number of active hydrogens that react with the isocyanate groups is stoichiometrically equal to the number of isocyanate groups in the polyisocyanate.

[0021] (1.3) Fatty acid esters Fatty acid esters function as antifoaming agents. When fatty acid esters are included in a composition, cells tend to coalesce more easily, resulting in foams with larger cell diameters and a more readily formed double-cell structure. Fatty acid esters (RCOOR', where R and R' may be the same or different) possess both hydrophilic and hydrophobic properties. Examples of fatty acid esters include sorbitan-based fatty acid esters, glycerol-based fatty acid esters, higher alcohol fatty acid esters, propylene-based fatty acid esters, and n-butyl stearate. Fatty acid esters may be used individually or in combination of two or more types. Examples of sorbitan-based fatty acid esters include sorbitan trioleate, sorbitan monooleate, sorbitan monostearate, sorbitan monoisostearate, sorbitan monopalmitate, sorbitan monolaurate, sorbitan tristearate, sorbitan sesquistearate, sorbitan sesquioleate, sorbitan sesquiisostearate, and sorbitan coconut oil fatty acid. Examples of glycerol fatty acid esters include glycerol monostearate, glycerol monobehenate, glycerol monooleate, glycerol monolaurate, stearing distearate, glycerol dibehenate, and glycerol diolate. Examples of higher alcohol fatty acid esters include stearyl stearate, lauryl stearate, lauryl laurylate, and stearyl behenate.

[0022] In the composition, the content of fatty acid esters per 100 parts by mass of the total amount of polyol is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 1.5 parts by mass or more. In the composition, the content of fatty acid esters per 100 parts by mass of the total amount of polyol is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less. Therefore, in the composition, the content of fatty acid esters per 100 parts by mass of the total amount of polyol is preferably 0.5 parts by mass or more and 20 parts by mass or less, more preferably 1 part by mass or more and 15 parts by mass or less, and even more preferably 1.5 parts by mass or more and 10 parts by mass or less.

[0023] (1.4) Alkyl ester having a structure derived from benzenepropanoic acid The alkyl ester having a structure derived from benzenepropanoic acid functions as an antifoaming agent. When the alkyl ester having a structure derived from benzenepropanoic acid is contained in the composition, cells tend to coalesce, forming a foam with a large cell diameter, and a double cell structure is easily formed. The alkyl ester having a structure derived from benzenepropanoic acid is represented by the following structural formula (1).

[0024]

Chemical Formula

[0025] R 1 Examples of the alkyl group having 1 to 10 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, and decyl group. R 2 , R 3 , R 4 , R 5 , R 6 Examples of the alkyl group having 1 to 6 carbon atoms in the above include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, pentyl group, and hexyl group.

[0026] As the alkyl ester having a structure derived from benzenepropanoic acid, a compound represented by the following structural formula (2) is preferable. In structural formula (2), R is an alkyl group having 1 to 10 carbon atoms. Examples of alkyl groups with 1-10 carbon atoms, represented by R in structural formula (2), include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups.

[0027] [ka]

[0028] As alkyl esters having a structure derived from benzenepropanoic acid, octyl=3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate (alkyl 4-hydroxy-3,5-di-tert-butylphenylpropionic acid (C=8)) and benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-C7-9-branched alkyl esters, which include the compound represented by the following structural formula (3), are preferably used.

[0029] [ka]

[0030] In the composition, the content of alkyl ester having a structure derived from benzenepropanoic acid, per 100 parts by mass of the total amount of polyol, is preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 0.8 parts by mass or more. In the composition, the content of alkyl ester fatty acid ester having a structure derived from benzenepropanoic acid, per 100 parts by mass of the total amount of polyol, is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 5 parts by mass or less. Therefore, in the composition, the content of alkyl ester having a structure derived from benzenepropanoic acid, per 100 parts by mass of the total amount of polyol, is preferably 0.3 parts by mass or more and 10 parts by mass or less, more preferably 0.5 parts by mass or more and 8 parts by mass or less, and even more preferably 0.8 parts by mass or more and 5 parts by mass or less.

[0031] (1.5) Foaming agent The composition may contain a blowing agent. The blowing agent is used to generate bubbles in the polyurethane. Blowing agents include chemical blowing agents that generate gas by thermal decomposition or chemical reaction (for example, water that reacts with isocyanate groups to produce CO2) and physical blowing agents that generate gas by pressure reduction or heating (for example, pentane, cyclopentane, methylene chloride, carbon dioxide, etc. dissolved in the resin under high pressure).

[0032] Among these, water is preferred as the foaming agent. This is because the reaction between water and isocyanate generates carbon dioxide gas, promoting foaming, while the reaction between water and isocyanate also forms urea bonds and urea bonds in the urethane polymer, thereby accelerating resin formation.

[0033] (1.6) Foam stabilizers The composition may contain a foam stabilizer. Generally, foam stabilizers are said to have the effect of improving the compatibility of each raw material used to manufacture polyurethane, adjusting the surface tension of the mixed raw materials, and stabilizing the bubbles generated by the foaming agent. Examples of foam stabilizers include silicone-based surfactants such as dimethylsiloxane-based foam stabilizers (polyethersiloxanes), and nonionic surfactants such as polyethylene glycol alkyl ethers and sorbitan fatty acid esters.

[0034] As described above, when a silicone-based foam stabilizer and defoamer are added to the composition simultaneously, optimizing the composition of the composition can yield a polyurethane foam that contains closed cells and has a double-cell structure. On the other hand, when a silicone-based foam stabilizer is not added to the composition, and an antifoaming agent is added, optimizing the composition of the composition can yield a polyurethane foam with few or no closed cells and a double-cell structure.

[0035] (1.7) Catalyst It is preferable that the composition includes a catalyst (resin-forming catalyst) to promote the reaction between the polyol and the polyisocyanate. Furthermore, when using a chemical blowing agent, particularly water, as a blowing agent, it is preferable to add a catalyst (foaming catalyst) to the raw materials to promote the reaction between water and polyisocyanate and generate gas. The type of catalyst is not particularly limited in this disclosure.

[0036] Examples of resinification catalysts include N,N-dimethylaminopropylurea, 1,2-dimethylimidazole, N,N,N'-trimethyl-N'-aminopropyl-bis(aminoethyl) ether, diethanolamine, 1-methylimidazole, N·(N',N'-dimethylaminoethyl)-morpholine, tetramethylguanidine, dimethylaminoethanol, triethylenediamine, N-methyl-N'-(2-hydroxyethyl)-piperazine, N,N,N',N'-tetramethylpropane-1,3-diamine, and N,N,N',N'-tetramethylpropane-1,3-diamine. Examples of amine-based catalysts include methylethylenediamine, N,N,N′,N″,N″-pentamethyl-(3-aminopropyl)ethylenediamine, N,N'-dimethylpiperazine, N,N,N',N'-tetramethylhexane-1,6-diamine, N,N,N',N",N"-pentamethyldipropylene-triamine, N-(2-hydroxyethyl)morpholine, ethylene glycol bis(3-dimethyl)-aminopropyl ether, N,N-dimethylcyclohexylamine, and N-methyl-N'-(2-dimethylamino)ethylpiperazine.

[0037] When the foaming agent is water, foaming catalysts include, for example, amine catalysts such as triethylamine, N,N,N′,N″,N″-pentamethyldiethylenetriamine, triethylenediamine, diethanolamine, bis(2-dimethylaminoethyl) ether, dimethylaminomorpholine, N-ethylmorpholine, and tetramethylguanidine.

[0038] (1.8) Others The composition may also contain other additives as appropriate, such as degassing agents, crosslinking agents, pigments, weathering agents, plasticizers, foaming aids, and flame retardants. Examples of degassing agents include polypropylene-polyethylene polyol compounds such as polyethylene glycol polypropylene glycol block copolymer. Examples of crosslinking agents include N,N-diethanolamine. Examples of pigments include a mixture of carbon pigment (black pigment) and polyether polyol dispersed in polyether polyol. Any plasticizer used for polyurethane foam is acceptable. Examples of weathering agents include bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate. Plasticizers are added, for example, to ensure an appropriate mixing ratio between the NCO-terminated urethane polymer and the foaming liquid, and to ensure stable mixing and stirring. As foaming aids, alternative fluorocarbons such as hydrofluoroolefins (HFOs) or hydrocarbons such as pentane can be used alone or in combination.

[0039] 2. Composition of the polyurethane foam molded body (2.1) Cell structure This section describes the cell diameter of polyurethane foam molded products. First, the method for measuring the "cell diameter" is explained. A sample of polyurethane foam molded product measuring 500 mm (length) x 500 mm (width) x 20 mm (height) is cut perpendicularly from the surface. The cross-section of the cut sample is photographed using an optical microscope. 100 cells are randomly selected from the cells appearing in the photographed cross-section, and the cell diameter of each cell is measured.

[0040] If the cell is perfectly circular, the cell diameter is the diameter of the cell. If the cell is irregularly shaped (such as an ellipse or other shape different from a perfect circle), the longest length in any direction (the length of the line segment (major axis) that can be drawn so as to fit within the captured cell) in the cell appearing on a horizontal plane is defined as the major axis diameter. The longest line segment (minor axis) that can be drawn so as to fit within the cell in a direction perpendicular to the major axis of the cell is defined as the minor axis diameter. This minor axis diameter is defined as the cell diameter.

[0041] Defoaming agents have the effect of increasing the cell diameter of the cells in a polyurethane foam molded article. Furthermore, when a composition containing a defoaming agent is used, a polyurethane foam molded article with a structure in which large-diameter and small-diameter cells are mixed (double-cell structure) can be obtained (see Figure 3). "Large-diameter cells" refer to cells with a diameter of 700 μm or more, for example. "Small-diameter cells" refer to cells with a diameter of less than 700 μm, for example.

[0042] "Average cell diameter" refers to the arithmetic mean of the cell diameters of 100 or more cells randomly selected from all the cells contained in the polyurethane foam molded article. The average cell diameter is 200 μm or more, preferably 300 μm or more, and more preferably 400 μm or more. The average cell diameter is preferably 850 μm or less, more preferably 800 μm or less, and even more preferably 750 μm or less. Therefore, the average cell diameter is 200 μm or more, preferably 200 μm or more and 850 μm or less, more preferably 300 μm or more and 800 μm or less, and even more preferably 400 μm or more and 750 μm or less.

[0043] "Standard deviation of cell diameter" refers to the standard deviation of the cell diameters of 100 or more cells randomly selected from all the cells contained in a polyurethane foam molded article. The standard deviation of cell diameter is 200 μm or more, preferably 230 μm or more, and more preferably 250 μm or more. The standard deviation of cell diameter is preferably 1000 μm or less, more preferably 900 μm or less, and even more preferably 800 μm or less. Therefore, the standard deviation of cell diameter is 200 μm or more, preferably 200 μm to 1000 μm, more preferably 230 μm to 900 μm, and even more preferably 250 μm to 800 μm.

[0044] The "coefficient of variation of cell diameter" is the value obtained by dividing the standard deviation of cell diameters by the mean cell diameter for 100 or more cells randomly selected from all the cells contained in the polyurethane foam molded article. The coefficient of variation of cell diameter is 0.37 or higher, preferably 0.4 or higher, and more preferably 0.45 or higher. The coefficient of variation of cell diameter is preferably 1.5 or lower, more preferably 1.2 or lower, and even more preferably 1.0 or lower. Therefore, the coefficient of variation of cell diameter is 0.37 or higher, preferably 0.37 or higher and 1.5 or lower, more preferably 0.4 or higher and 1.2 or lower, and even more preferably 0.45 or higher and 1.0 or lower.

[0045] "Minimum cell diameter" refers to the smallest cell diameter among 100 or more cells randomly selected from all cells contained in the polyurethane foam molded article. The minimum cell diameter is preferably 20 μm or more, more preferably 40 μm or more, and even more preferably 60 μm or more. The minimum cell diameter is preferably 200 μm or less, more preferably 180 μm or less, and even more preferably 160 μm or less. Therefore, the minimum cell diameter is preferably 20 μm or more and 200 μm or less, more preferably 40 μm or more and 180 μm or less, and even more preferably 60 μm or more and 160 μm or less.

[0046] "Maximum cell diameter" refers to the largest cell diameter among 100 or more cells randomly selected from all cells contained in the polyurethane foam molded article. The maximum cell diameter is preferably 700 μm or more, more preferably 1000 μm or more, and even more preferably 1200 μm or more. The maximum cell diameter is preferably 5000 μm or less, more preferably 4000 μm or less, and even more preferably 3000 μm or less. Therefore, the maximum cell diameter is preferably 700 μm or more and 5000 μm or less, more preferably 1000 μm or more and 4000 μm or less, and even more preferably 1200 μm or more and 3000 μm or less.

[0047] The difference between the minimum and maximum cell diameters is preferably 500 μm or more, more preferably 800 μm or more, and even more preferably 1000 μm or more. The difference between the minimum and maximum cell diameters is preferably 3000 μm or less, more preferably 2800 μm or less, and even more preferably 2500 μm or less. Therefore, the difference between the minimum and maximum cell diameters is preferably 500 μm or more and 3000 μm or less, more preferably 800 μm or more and 2800 μm or less, and even more preferably 1000 μm or more and 2500 μm or less.

[0048] (2.2) Loss Factor In a polyurethane foam molded article, the loss coefficient at the anti-resonance point between 450 Hz and 550 Hz, measured in accordance with JIS K 7391:2008, is preferably 0.330 or higher, more preferably 0.340 or higher, and even more preferably 0.350 or higher. The upper limit of the loss coefficient at the anti-resonance point between 450 Hz and 550 Hz is not particularly limited, but may be 0.5 or lower.

[0049] In a polyurethane foam molded article, the loss coefficient at the anti-resonance point between 1950 Hz and 2200 Hz, measured in accordance with JIS K 7391:2008, is preferably 0.130 or higher, more preferably 0.14 or higher, and even more preferably 0.15 or higher. The upper limit of the loss coefficient at the anti-resonance point between 1950 Hz and 2200 Hz is not particularly limited, but may be 0.2 or lower.

[0050] In a polyurethane foam molded article, the loss coefficient at the anti-resonance point between 1100 Hz and 1300 Hz, measured in accordance with JIS K 7391:2008, is preferably 0.090, more preferably 0.1 or higher, and even more preferably 0.11 or higher. The upper limit of the loss coefficient at the anti-resonance point between 1100 Hz and 1300 Hz is not particularly limited, but may be 0.2 or lower.

[0051] (2.3) Air permeability (Method B) The air permeability of a polyurethane foam molded article, as measured according to JIS K6400-7 Method B, is 0.2 cm. 3 / cm2 Preferably 0.25 cm or more 3 / cm 2 / s or more is more preferable, 0.30cm 3 / cm 2 A value of / s or higher is even more preferable. The air permeability measured according to JIS K6400-7 Method A is 5cm 3 / cm 2 Preferably less than / s, and 3cm 3 / cm 2 / s or less is more preferable, 2cm 3 / cm 2 A value of less than / s is even more preferable. Therefore, the air permeability measured according to JIS K6400-7 Method A is 0.2 cm 3 / cm 2 / s or more 5cm 3 / cm 2 Preferably less than / s, and 0.25cm 3 / cm 2 / s or more 3cm 3 / cm 2 / s or less is more preferable, and 0.30cm 3 / cm 2 / s or more 2cm 3 / cm 2 / s or less is even more preferable.

[0052] (2.4)Hardness In polyurethane foam molded articles, the Asker F hardness is preferably 70 degrees or higher, more preferably 75 degrees or higher, and even more preferably 80 degrees or higher. The Asker F hardness is preferably 98 degrees or lower, more preferably 97 degrees or lower, and even more preferably 96 degrees or lower. Therefore, the Asker F hardness is preferably 70 degrees or higher and 98 degrees or lower, more preferably 75 degrees or higher and 97 degrees or lower, and even more preferably 80 degrees or higher and 96 degrees or lower. Note that the Asker F hardness refers to the hardness determined by the Asker rubber hardness meter type F.

[0053] (2.5) Density The apparent density of the polyurethane foam molded article (according to JIS K7222;2005) is 40 kg / m³. 3 More than 300kg / m 3 The following is preferable: 50 kg / m 3More than 250kg / m 3 The following is more preferable: 60 kg / m 3 More than 180kg / m 3 The following are even more preferable.

[0054] 3. Method for manufacturing a polyurethane foam molded article The method for producing a polyurethane foam molded article according to the present disclosure comprises a first step of obtaining a composition (raw material mixture) containing a polyol, a polyisocyanate, and an alkyl ester having a structure derived from a fatty acid ester or benzenepropanoic acid, and a second step of reacting the composition. In the second step, for example, the composition is poured into a suitable mold, and the composition is reacted to perform mold molding. This yields the polyurethane foam molded article according to the present disclosure.

[0055] 4.Applications The polyurethane foam molded articles of this disclosure can be used for a variety of applications. For example, the polyurethane foam molded articles of this disclosure can be used as vibration damping members. Examples of vibration damping members include vehicle floor silencers and insulators placed around the power source of a vehicle. Figure 1 schematically shows a vehicle floor silencer 10 using the polyurethane foam molded article of this disclosure. Figure 2 schematically shows an insulator 20 using the polyurethane foam molded article of this disclosure. As shown in Figure 2, the insulator 20 is placed around the power source of a vehicle (engine 31, motor 32). [Examples]

[0056] The following will provide a more detailed explanation using examples.

[0057] 1. Fabrication of polyurethane foam molded bodies Compositions were prepared according to the mixing ratios shown in Tables 1 and 2, and polyurethane foam molded articles of the examples and comparative examples were produced by mold molding. Examples 1-6 contain an antifoaming agent in the composition. Comparative Examples 1-3 do not contain an antifoaming agent in the composition. Details of the raw materials in Tables 1 and 2 are shown below. In Tables 1 and 2, the mixing ratios represent the mixing ratio (parts by mass) when the total polyol is 100 parts by mass. In Tables 1 and 2, the numerical values ​​of each component without a unit listed, except for the index, represent parts by mass.

[0058] [Table 1]

[0059] [Table 2]

[0060] The details of the raw materials for the polyurethane foam molded product are as follows: Polyol 1: Polyether polyol, polypropylene oxide with ethylene oxide at the terminus, hydroxyl value 35 mg KOH / g, number of functional groups 3, number average molecular weight 5000, EO ratio 14 mol% • Polyol 2: Polyether polyol, polypropylene oxide with ethylene oxide at the terminus, 3 functional groups, number average molecular weight 7000, EO ratio 14 mol% • Catalyst 1: N,N-dimethylaminopropylurea (DABCO® NE1070, manufactured by EVONIK). • Catalyst 2: 1,2-dimethylimidazole (DABCO® 2040, manufactured by EVONIK). • Catalyst 3: N,N,N'-trimethyl-N'-aminopropyl-bis(aminoethyl) ether (DABCO® NE300, manufactured by EVONIK) • Catalyst 4: Diethanolamine (DEA, 3 functional groups, hydroxyl value 1603 mg KOH / g, manufactured by Mitsui Chemicals, Inc.) • Catalyst 5: Glycol solution of tertiary amine (DABCO® 3040A, manufactured by EVONIK) • Antifoaming agent 1: Sorbitan trioleate (Leodol SP-O30V, manufactured by Kao Corporation) • Antifoaming agent 2: Benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-C7-9 branched alkyl ester (Ortegol 500, manufactured by EVONIK) • Antifoaming agent 3: Fatty acid ester (Ortegol CC2, manufactured by EVONIK) • Foaming agent: Water • Weather-resistant agent: Bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate (UV65, manufactured by SABO SpA). • Pigment: A mixture of carbon pigment (black pigment) and polyether polyol dispersed in polyether polyol (PC4114T-T, manufactured by Dainippon Ink Co., Ltd.) • Degassing agent: Polyethylene glycol polypropylene glycol block copolymer (VORANOL® CP1421, manufactured by Dow Chemical Company) • Crosslinking agent: N,N-diethanolamine (DEA80, manufactured by Mitsui Chemicals, Inc.) • Foam stabilizer: Dimethylsiloxane (B8738LF2, manufactured by EVONIK) • Isocyanate 1: Modified MDI, NCO ratio = 27.6% • Isocyanate 2: Crude MDI, NCO content = 31.5%

[0061] 2. Evaluation Next, the polyurethane foam molded articles of each example and comparative example were evaluated as follows.

[0062] [Evaluation of cell diameter] Each polyurethane foam molded body in the examples and comparative examples was cut vertically from the surface side, measuring 500 mm in length, 500 mm in width, and 20 mm in height. The cross-section of the cut sample was photographed using an optical microscope. Figure 3 is a schematic diagram of the top surface of the cut sample of Example 1. In other words, Figure 3 is a schematic cross-sectional view showing an example of the internal structure of the polyurethane foam molded body 100. As shown in Figure 3, the polyurethane foam molded body 100 has a structure (double cell structure) in which large-diameter cells 110 and small-diameter cells 120 are mixed. 100 cells were randomly selected from the cells appearing in the photographed cross-sections described above, and the cell diameter of each cell was measured.

[0063] Here, if the cell is a perfect circle, the cell diameter is defined as the diameter of the cell. If the cell has an irregular shape (such as an ellipse or a shape other than a perfect circle), the longest length in any direction that can be drawn within the cell in the cross-sectional photograph (the length of the line segment (major axis) that can be drawn within the photographed cell) is defined as the major axis diameter. The longest line segment (minor axis) that can be drawn within the cell in a direction perpendicular to the major axis of the cell is defined as the minor axis diameter. This minor axis diameter is defined as the cell diameter.

[0064] For example, as shown in Figure 4, in a cell 130 that is not perfectly circular, the line segment L1 that has the longest length in any direction is the major axis. The line segment L2 that can be drawn perpendicular to line segment L1 and fits within the cell 130 is the minor axis. Therefore, in the case of cell 130 in Figure 4, line segment L2 is the cell diameter.

[0065] In the examples and comparative examples, the mean, standard deviation, coefficient of variation, minimum cell diameter, maximum cell diameter, and the difference between the minimum and maximum cell diameters were calculated for 100 selected cells. The calculation results are shown in Tables 3 and 4, in the columns for "Mean cell diameter," "Standard deviation of cell diameter," "Coefficient of variation of cell diameter," "Minimum cell diameter," "Maximum cell diameter," and "Difference between minimum and maximum cell diameters."

[0066] [Table 3]

[0067] [Table 4]

[0068] [Evaluation of the loss factor] In each polyurethane foam molded article of the examples and comparative examples, the loss coefficient at each anti-resonance point of the sample for loss coefficient measurement was determined by the method described in the embodiment according to JIS K 7391:2008. The sample size was 30 mm × 300 mm × 20 mm thick. The sample was attached to a steel plate substrate measuring 30 mm × 300 mm × 1.0 mm thick. The loss coefficient was also determined for the steel plate substrate alone. The measurement results are shown in the "Loss Coefficient" column of Tables 5 and 6.

[0069] [Table 5]

[0070] [Table 6]

[0071] [Evaluation of ventilation] In each polyurethane foam molded article of Examples 1-3 and Comparative Examples 1 and 2, the air permeability (Method B) was determined using the method described in the embodiment according to JIS K6400-7 Method B. For each polyurethane foam molded article sample with a thickness of 20 mm and a horizontal surface of 500 mm x 500 mm, five locations forming a 150 mm x 150 mm square on the horizontal surface were identified and used as sampling locations. The average value of the measurement results from the five locations is shown in the "Air Permeability" column of Table 5.

[0072] [Hardness evaluation] The Asker F hardness was determined for each polyurethane foam molded article in the examples and comparative examples using an Asker rubber hardness tester Type F. The measurement results are shown in the "Asker F Hardness" column of Tables 5 and 6.

[0073] 3. Evaluation Results As shown in Table 3, Example 1, which used defoaming agent 3, showed significantly larger average cell diameters, standard deviations, and coefficients of variation of cell diameters compared to Comparative Example 1, which did not use defoaming agent. Examples 2 and 3, which also used defoaming agent, showed larger coefficients of variation of cell diameters. Similarly, as shown in Table 4, Examples 4-6, which used defoaming agent 3, showed significantly larger average cell diameters, standard deviations, and coefficients of variation of cell diameters compared to Comparative Examples 2 and 3, which did not use defoaming agent. This suggests that the use of defoaming agent 3 facilitated the formation of a double-cell structure in the polyurethane foam molded article.

[0074] As shown in Table 5, Examples 1-3, which used an antifoaming agent, showed larger loss coefficients at the anti-resonance point between 450 Hz and 550 Hz, and between 1950 Hz and 2200 Hz, compared to Comparative Example 1, which did not use an antifoaming agent. In other words, Examples 1-3, which used an antifoaming agent, showed improved vibration damping compared to Comparative Example 1, which did not use an antifoaming agent.

[0075] As shown in Table 6, Examples 4-6, which use an antifoaming agent, have a larger loss coefficient at the anti-resonance point between 1100 Hz and 1300 Hz compared to Comparative Examples 2 and 3, which do not use an antifoaming agent. In other words, Examples 4-6, which use an antifoaming agent, have improved vibration damping compared to Comparative Examples 2 and 3, which do not use an antifoaming agent.

[0076] As shown in Table 5, Example 1, which uses defoaming agent 3, has larger loss coefficients at the anti-resonance point between 450 Hz and 550 Hz, and between 1950 Hz and 2200 Hz, compared to Examples 2 and 3, which use defoaming agents 1 and 2, respectively. Furthermore, Example 1, which uses defoaming agent 3, has higher air permeability compared to Examples 2 and 3, which use defoaming agents 1 and 2, respectively. It is thought that Example 1, which uses defoaming agent 3, has improved vibration damping performance because the double-cell structure is more pronounced despite the increased air permeability compared to Examples 2 and 3, which use defoaming agents 1 and 2, respectively.

[0077] 4. Effects of the Examples According to the above embodiments, the vibration damping properties of the polyurethane foam molded body can be improved.

[0078] This disclosure is not limited to the embodiments detailed above, and various modifications or alterations are possible. [Explanation of Symbols]

[0079] 10: Dual-purpose floor silencer 20: Insulator 31: Engine 32: Motor 110: Large diameter cell 120: Small diameter cell 130: Cell

Claims

1. A polyurethane foam molded article obtained from a composition containing a polyol, a polyisocyanate, and an alkyl ester having a structure derived from a fatty acid ester or benzenepropanoic acid, The coefficient of variation, obtained by dividing the standard deviation of cell diameter by the mean cell diameter, is 0.37 or greater. A polyurethane foam molded article having an average cell diameter of 200 μm or more and 850 μm or less.

2. A polyurethane foam molded article obtained from a composition containing a polyol, a polyisocyanate, and a fatty acid ester, The average cell diameter is between 400 μm and 850 μm. A polyurethane foam molded article having a standard deviation of cell diameter of 200 μm or more and 1000 μm or less.

3. A polyurethane foam molded article according to claim 1 or claim 2, wherein the loss factor at an anti-resonance point between 450 Hz and 550 Hz, measured in accordance with JIS K 7391:2008, is 0.330 or more, and / or the loss factor at an anti-resonance point between 1950 Hz and 2200 Hz is 0.130 or more.

4. A polyurethane foam molded article according to claim 1 or claim 2, wherein the loss coefficient at the anti-resonance point between 1100 Hz and 1300 Hz, measured in accordance with JIS K 7391:2008, is 0.090 or greater.

5. A polyurethane foam molded body according to claim 1 or claim 2, which is a vibration damping member.

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