JP2023132811A - flexible polyurethane foam - Google Patents

Abstract

To provide a flexible polyurethane foam excellent in sound absorbency even if its thickness is as thin as 10 mm or so, the flexible polyurethane foam capable of exhibiting sufficient sound absorbency even in a low frequency region of 1250 Hz or lower, specifically.SOLUTION: In a flexible polyurethane foam, a difference is within 0.30, with regard to the difference between a maximum value and a minimum value in a range from -20°C to 100°C of a value of loss tangent (tanδ) obtained by dynamic viscoelasticity measurement at frequency 100 Hz, at a rate of temperature rise 2°C/min., and in a compression mode.SELECTED DRAWING: None

Description

FIELD OF THE INVENTION The present invention relates to flexible polyurethane foams.

Flexible polyurethane foam is used in a wide range of applications, including daily necessities, automobile interior materials, clothing, sporting goods, medical materials, and civil engineering and construction materials. Among these application fields, there is a demand for further noise reduction by improving the performance of soundproofing materials such as sound absorbing materials and sound insulating materials, particularly in transportation vehicles such as automobiles, and buildings such as houses.

Particularly in the field of automobiles, with the regulation values of external noise regulations being applied and regulations becoming stricter in the future, reducing engine transmitted sound and radiated sound from tires is an urgent issue, and the use of sound-absorbing materials. Needs are increasing. In response to these demands, it is possible to increase the sound absorption performance and vibration absorption performance relatively easily by increasing the thickness of the base material. There are concerns that it will not be possible to secure sufficient space. Therefore, it is necessary to improve the sound absorption performance and reduce the thickness of the base material to about 10 mm.

Various efforts have been made to improve this sound absorption performance. For example, Patent Document 1 discloses a sound absorbing material having specific flow resistance, Young's modulus, and loss coefficient.

Japanese Patent Application Publication No. 2009-040071

According to Patent Document 1, when examining each sound absorption property, a sound absorbing material with a thickness of 10 mm and ^an area of 0.95 m2 is used, but there is still room for improvement in sound absorption properties, and in particular, as shown in FIG. As shown, the sound absorption coefficient does not reach 0.2 in the low frequency region of 1250 Hz or less, and it is difficult to say that the sound absorption performance is sufficient.

Therefore, an object of the present invention is to provide a flexible polyurethane foam that has excellent sound absorption properties even when the thickness is as thin as about 10 mm, and in particular exhibits sufficient sound absorption properties even in the low frequency range of 1250 Hz or less. be.

The present invention solves the problem of the maximum and minimum values of loss tangent (tan δ) between -20°C and 100°C determined by dynamic viscoelasticity measurement in compression mode at a frequency of 100Hz and a heating rate of 2°C/min. Provided is a flexible polyurethane foam in which the difference is within 0.30.

This composition has excellent sound absorption properties even when the thickness is as thin as about 10 mm, and exhibits sufficient sound absorption properties even in the low frequency range of 500 Hz to 1250 Hz. The difference between the maximum and minimum values of the loss tangent (tan δ) between -20°C and 100°C determined by dynamic viscoelasticity measurement in compression mode at a frequency of 100Hz and a heating rate of 2°C/min is calculated as 0. It has now been discovered that by setting the thickness within 30, a surprising effect can be obtained in that even when the thickness is thin, excellent sound absorption properties are exhibited in the low frequency range.

The flexible polyurethane foam may have a complex modulus of elasticity of 0.5 or less at 25°C determined by dynamic viscoelasticity measurement in compression mode at a frequency of 100Hz and a heating rate of 2°C/min. When the complex modulus of elasticity is the above value, even if the flexible polyurethane foam is thin, the sound absorption properties in the low frequency region of 1250 Hz or less are particularly excellent.

The flexible polyurethane foam may be composed of a reactant of a composition including a polyisocyanate, a polyol, and a blowing agent. Further, the polyol may contain at least one selected from the group consisting of chlorinated polymer particle-containing polyols and chlorinated polyols. Furthermore, as the chlorinated polyol, it is possible to contain at least one of a chlorinated polyester polyol and a chlorinated polycarbonate polyol. These chlorinated polyols improve physical properties such as hardness of the flexible polyurethane foam itself, and also contribute to improving sound absorption in the low frequency range of 1250 Hz or less.

Further, as the polyol, a polyether polyol having an average number of functional groups of 2.0 to 4.0 and/or a castor oil polyol having an average number of functional groups of 2.0 to 4.0 may be further contained. Note that the functional group in the average number of functional groups means an active hydrogen group (particularly a hydroxyl group).

The polyisocyanate may include an MDI polyisocyanate composed of monomeric MDI and polymeric MDI. In this case, the content of monomeric MDI is 50 to 85% by mass with respect to the total amount of monomeric MDI and polymeric MDI, and monomeric MDI is composed of 4,4'-MDI and isomers of 4,4'-MDI. It is composed of certain 2,2'-MDI and 2,4'-MDI, and the total content of isomers can be 10 to 50% by mass based on monomeric MDI. Note that MDI means diphenylmethane diisocyanate.

By setting the MDI content to 85% by mass or less, the storage stability of the polyisocyanate component at low temperatures and the durability of the resulting flexible polyurethane foam can be improved, and by setting the MDI content to 50% by mass or more, the elongation of the flexible polyurethane foam can be greatly increased. This can improve foam strength. By setting the isomer content to 10% by mass or more based on the total amount of MDI, it is possible to improve the storage stability of polyisocyanate at low temperatures, making storage easier and making it possible to avoid constant heating inside the foam molding machine. Become. Furthermore, the molding stability of the flexible polyurethane foam is improved, making it difficult for the foam to collapse during foaming. By controlling the isomer content to 50% by mass or less, sufficient reactivity can be obtained, the molding cycle can be improved, and the problem of shrinkage after molding is less likely to occur.

Flexible polyurethane foam has an average sound absorption coefficient of 500 Hz, 630 Hz, 800 Hz, 1000 Hz and 1250 Hz at a thickness of 10 mm, measured at a temperature of 20°C, humidity of 50% RH, and 1 atm, in accordance with JIS A1405-2:2007. It exhibits excellent sound absorption properties in the low frequency range, with a value of 0.35 or higher. Hereinafter, the sound absorption coefficient will be measured under the above conditions of temperature, humidity, pressure, and thickness.

The flexible polyurethane foam can have a density of 25 to 200 kg/m ³ , a C hardness of 0.1 to 20 points, and an air permeability of 0.1 to 30 cm ³ /cm ² /sec. By having such characteristics, sound absorption characteristics suitable for practical use can be obtained even in areas where sufficient space cannot be secured in transportation machines, buildings, etc.

According to the present invention, there is provided a flexible polyurethane foam that exhibits excellent sound absorption properties even when the thickness is as thin as about 10 mm, and in particular exhibits sufficient sound absorption properties even in the low frequency range of 1250 Hz or less.

FIG. 3 is a diagram showing the loss tangent (tan δ) of the flexible polyurethane foam of Example 1 between −20° C. and 100° C. FIG. 3 is a diagram showing the loss tangent (tan δ) of the flexible polyurethane foam of Example 2 between −20° C. and 100° C. FIG. 3 is a diagram showing the loss tangent (tan δ) of the flexible polyurethane foam of Example 3 between −20° C. and 100° C. FIG. 3 is a diagram showing the loss tangent (tan δ) of the flexible polyurethane foam of Example 4 between −20° C. and 100° C. FIG. 3 is a diagram showing the loss tangent (tan δ) of the flexible polyurethane foam of Example 5 between −20° C. and 100° C. FIG. 3 is a diagram showing the loss tangent (tan δ) of the flexible polyurethane foam of Example 6 between −20° C. and 100° C. FIG. 2 is a diagram showing the loss tangent (tan δ) of the flexible polyurethane foam of Comparative Example 1 between -20°C and 100°C. FIG. 3 is a diagram showing the loss tangent (tan δ) of the flexible polyurethane foam of Comparative Example 2 between −20° C. and 100° C.

The polyurethane foam according to the embodiment is a flexible polyurethane foam. Here, the flexible polyurethane foam refers to a reversibly deformable foam that has an open cell structure and exhibits high air permeability. 161-233, see Keiji Iwata, "Polyurethane Resin Handbook" (first edition, 1987), Nikkan Kogyo Shimbun, pp. 150-221].

The physical properties of flexible polyurethane foam are difficult to specify because they vary depending on the chemical structure of the polyol and isocyanate used in its production, chemical factors such as the amount of blowing agent, isocyanate index, cell structure, etc. However, in general, the density (can be measured as apparent density; the same applies hereinafter) is 10 to 100 kg/m ³ (JIS K 6401), and the compressive strength (ILD 25%) is 2 to 80 kgf (20 to 800 N). ) (JIS K 6401), and the elongation rate is in the range of 80 to 500% (JIS K 6301) [for example, Gunter Oertel, "Polyurethane Handbook" (1985 edition) Hanser Publisher (Germany), pp. 184 to 191; See pages 212-218, Keiji Iwata, "Polyurethane Resin Handbook" (first edition, 1987), Nikkan Kogyo Shimbun, pages 160-166 and 186-191].

In addition, semi-rigid polyurethane foam is a reversibly deformable foam that has an open cell structure similar to flexible polyurethane foam and exhibits high air permeability, although its foam density and compressive strength are higher than that of flexible polyurethane foam. The raw materials used in the production, such as polyols and isocyanates, are the same as those for flexible polyurethane foam, so it is generally classified as flexible polyurethane foam [for example, Gunter Oertel, "Polyurethane Handbook" (1985 edition) Hanser Publisher (Germany), pp. 223-233; see Keiji Iwata, "Polyurethane Resin Handbook" (first edition, 1987), Nikkan Kogyo Shimbun, pp. 211-221]. The physical properties of semi-rigid polyurethane foam are not particularly limited, but generally have a density of 40 to 800 kg/m ³ , a 25% compressive strength of 0.1 to 2 kgf/cm ² (9.8 to 200 kPa), The elongation rate is in the range of 40 to 200%.

Rigid polyurethane foams, on the other hand, are highly crosslinked, closed-cell structures that cannot be reversibly deformed, and have properties that are completely different from flexible and semi-rigid polyurethane foams [e.g. Gunter Oertel, “Polyurethane Foams] (1985 edition) Hanser Publisher (Germany), pages 234-313; see Keiji Iwata, "Polyurethane Resin Handbook" (first edition 1987) Nikkan Kogyo Shimbun, pages 224-283]. The properties of the rigid foam are not particularly limited, but generally the density is in the range of 20 to 100 kg/m ³ and the compressive strength is in the range of 0.5 to 10 kgf/cm ² (50 to 1000 kPa).

The flexible polyurethane foam in the present invention includes not only the flexible polyurethane foam having the above-mentioned characteristics, but also the semi-rigid polyurethane foam having the above-mentioned characteristics.

The polyisocyanate used to obtain the flexible polyurethane foam may be any compound having at least two isocyanate groups. Examples of such compounds include aromatic isocyanate compounds, aliphatic isocyanate compounds, alicyclic isocyanate compounds, and polyisocyanate derivatives thereof.

Aromatic isocyanate compounds include tolylene diisocyanate (2,4- or 2,6-tolylene diisocyanate or a mixture thereof) (TDI), phenylene diisocyanate (m-, p-phenylene diisocyanate or a mixture thereof, 4, 4'-diphenyl diisocyanate, diphenylmethane diisocyanate (4,4'-, 2,4' or 2,2'-diphenylmethane diisocyanate or mixtures thereof) (MDI), 4,4'-toluidine isocyanate (TODI), 4,4' - diphenyl ether diisocyanate, xylylene diisocyanate (1,3- or 1,4-xylylene diisocyanate or a mixture thereof) (XDI), tetramethyl xylylene diisocyanate (1,3- or 1,4-tetramethyl xylylene diisocyanate or its mixture) mixture) (TMXDI), ω,ω'-diisocyanate-1,4-diethylbenzene, naphthalene diisocyanate (1,5-, 1,4- or 1,8-naphthalene diisocyanate or mixtures thereof) (NDI), triphenylmethanetri Isocyanate, tris (isocyanate phenyl) thiophosphate, polymethylene polyphenylene polyisocyanate, nitrodiphenyl-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diphenylpropane diisocyanate, Examples include 3,3'-dimethoxydiphenyl-4,4'-diisocyanate.

Aliphatic isocyanate compounds include trimethylene diisocyanate, 1,2-propylene diisocyanate, butylene diisocyanate (tetramethylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate). , hexamethylene diisocyanate, pentamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,-trimethylhexamethylene diisocyanate, 2,6-diisocyanate methyl capate, lysine diisocyanate, lysine ester triisocyanate, 1,6 , 11-undecane triisocyanate, 1,3,6-hexamethylene triisocyanate, trimethylhexamethylene diisocyanate, decamethylene diisocyanate and the like.

Examples of monocyclic alicyclic isocyanate compounds include 1,3-cyclopentane diisocyanate, 1,3-cyclopentene diisocyanate, cyclohexane diisocyanate (1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate), 3- Isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), methylenebis(cyclohexylisocyanate (4,4'-, 2,4'- or 2,2'-methylenebis(cyclohexylisocyanate or mixtures thereof)) (hydrogenated MDI), methylcyclohexane diisocyanate (methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, bis(isocynate methyl)cyclohexane (1,3- or 1,4-bis(isocyanate methyl) )cyclohexane or a mixture thereof) (hydrogenated XDI), dimer acid diisocyanate, transcyclohexane 1,4-diisocyanate, hydrogenated tolylene diisocyanate (hydrogenated TDI), hydrogenated tetramethylxylylene diisocyanate (hydrated TMXDI), etc. It will be done.

Examples of the crosslinked alicyclic isocyanate compound include norbornene diisocyanate, methyl norbornane diisocyanate, bicycloheptane triisocyanate, methyl diisocyanate, bicycloheptane, and di(diisocyanatomethyl)tricyclodecane.

In the composition for forming flexible polyurethane foam, MDI (diphenylmethane diisocyanate) can be suitably used. As MDI, monomeric MDI (M-MDI ), but MDI-based polyisocyanates, which are a mixture of M-MDI and polyphenylene polymethylene polyisocyanate, ie, polymeric MDI (P-MDI), may also be used.

In addition to M-MDI and a mixture of M-MDI and P-MDI, various modified products thereof such as urethane modified products, urea modified products, allophanate modified products, nurate modified products, and biuret modified products can also be used. .

The content of M-MDI in the MDI polyisocyanate is preferably in the range of 50 to 85% by weight, and may be 60 to 85% by weight, 70 to 85% by weight, or 75 to 85% by weight. If the M-MDI content exceeds 85% by mass, the storage stability of the polyisocyanate component at low temperatures and the durability of the resulting flexible polyurethane foam may decrease, while if it is less than 50% by mass, the crosslinking density may increase. Accordingly, the elongation of the flexible polyurethane foam may decrease, making it difficult to obtain sufficient foam strength.

Furthermore, the total content of 2,2'-MDI and 2,4'-MDI (hereinafter sometimes referred to as "isomer content") with respect to the total amount of M-MDI is 10 to 50% by mass. It is preferably 10 to 45% by weight, and may be 10 to 40% by weight.

If the content of 2,2'-MDI and 2,4'-MDI is less than 10% by mass based on the total amount of monomeric MDI, the storage stability at low temperatures of the polyisocyanate component may be impaired, and the isocyanate storage location and Continuous heating of piping and the inside of the foam molding machine may be required. Furthermore, the molding stability of the flexible polyurethane foam may be impaired, and the foam may collapse during foaming. On the other hand, if it exceeds 50% by mass, the reactivity decreases, which may cause problems such as lengthening of the molding cycle, high cell foam ratio, and shrinkage after molding.

The above-mentioned MDI-based polyisocyanate includes M-MDI content of 85% by mass, P-MDI content of 15% by mass, isomers of 4,4'-MDI in M-MDI (2,4'-MDI and 2,2 '-MDI) content of 38% by mass (manufactured by Tosoh Corporation, product name: CEF-550), M-MDI content of 76% by mass, P-MDI content of 24% by mass, M-MDI Polyisocyanate (manufactured by Tosoh Corporation, trade name: CEF-549) having a 4,4'-MDI isomer (2,4'-MDI and 2,2'-MDI) content of 38% by mass is mentioned.

Note that polyisocyanate or its derivative may be used alone or in combination of two or more.

The polyol used to obtain the flexible polyurethane foam contains at least one type selected from the group consisting of chlorinated polymer particle-containing polyols and chlorinated polyols (hereinafter sometimes collectively referred to as "chlorine-containing polyol component"). You can stay there. That is, the polyol can be only a chlorine-containing polyol component, a combination of a polyol other than a chlorine-containing polyol (chlorine-free polyol component) and a chlorine-containing polyol, or only a chlorine-free polyol component.

When using a chlorine-containing polyol, the chlorine concentration of the chlorine-containing polyol component is 2.0% to 15.5%, based on the total amount of polyol (total amount of chlorine-containing polyol component and chlorine-free polyol component). It may be .0% to 15.0%, 3.0 to 14.0%, 3.5 to 13.5%, or 3.5 to 13.0%. The chlorine concentration calculated from only the chlorine-containing polyol component, not the total amount of polyol, is more than 13.0% and less than 23.0%, 15.0-22.0%, 17.0-22.0%, 18 It may be .0 to 22.0%, or 18.0 to 21.0%, or it may be 19.0% or 20.0%.

In addition, when calculating the chlorine concentration, when the polyol contains a plurality of chlorine-containing polyol components, a weighted average is used. The chlorine concentration is calculated based on information on the raw materials used (for example, information on the type and amount of the compound used to contain chlorine) or a known method for detecting the amount of chlorine in a polymer. For example, when introducing chlorine using epichlorohydrin, it can be calculated according to the following formula.
Chlorine concentration (%) = (molecular weight of chlorine-containing polyol component - molecular weight of initiator) x (chlorine atomic weight ÷ molar mass of epichlorohydrin) ÷ molecular weight of chlorine-containing polyol component x 100

When using a chlorine-containing polyol, the content ratio of the chlorine-containing polyol component based on the total amount of polyol can be 10 to 100% by mass, 10 to 80% by mass, or 20 to 70% by mass, and polyisocyanate The content ratio of polyol (total amount) to (total amount) can be adjusted so as to correspond to the isocyanate index described below.

The chlorine-free polyol component used to obtain the flexible polyurethane foam may be any compound that contains an active hydrogen group as a reactive group with an isocyanate group and does not contain chlorine. Examples of chlorine-free polyol components include polyester polyols, polyether polyols, polycarbonate polyols, polyolefin polyols, acrylic polyols, silicone polyols, castor oil polyols, fluorine polyols, transesterified products of two or more types of polyols, and polyisocyanates. Hydroxyl group-terminated prepolymers subjected to urethanization reaction are preferably used, and these may be used alone or as a mixture of two or more.

Examples of polyester polyols include phthalic acid, isophthalic acid, terephthalic acid, naphthalene dicarboxylic acid, succinic acid, tartaric acid, oxalic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, glutaconic acid, azelaic acid, sebacic acid, Dicarboxylic acids such as 1,4-cyclohexyldicarboxylic acid, α-hydromuconic acid, β-hydromuconic acid, α-butyl-α-ethylglutaric acid, α,β-diethylsuccinic acid, maleic acid, fumaric acid, etc., or dicarboxylic acids such as these one or more types of anhydrides, etc., and ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5 -pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, Neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, ethylene oxide and propylene oxide adducts of bisphenol A, bis(β-hydroxyethyl)benzene, xylylene glycol, glycerin Examples include those obtained from a polycondensation reaction with one or more types of low-molecular polyols having a molecular weight of 500 or less, such as trimethylolpropane and pentaerythritol. Also included are lactone-based polyester polyols obtained from ring-opening polymerization of cyclic ester (so-called lactone) monomers such as ε-caprolactone, alkyl-substituted ε-caprolactone, δ-valerolactone, and alkyl-substituted δ-valerolactone. Furthermore, a polyester-amide polyol obtained by replacing a part of the low-molecular polyol with a low-molecular polyamine such as hexamethylene diamine, isophorone diamine, or monoethanolamine or a low-molecular amino alcohol can also be used.

Examples of polyether polyols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol. , 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol , cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, bisphenol A, bis(β-hydroxyethyl)benzene, xylylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc. Start with a compound having two or more active hydrogen groups, preferably two to three active hydrogen groups, such as polyols or low-molecular polyamines such as ethylenediamine, propylenediamine, toluenediamine, metaphenylenediamine, diphenylmethanediamine, and xylylenediamine. As agents, polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, etc., or alkyl glycidyl ethers such as methyl glycidyl ether, and aryl glycidyl ethers such as phenyl glycidyl ether. , polyether polyols obtained by ring-opening polymerization of cyclic ether monomers such as tetrahydrofuran.

Examples of polycarbonate polyols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, Cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, ethylene oxide and propylene oxide adducts of bisphenol A, bis(β-hydroxyethyl)benzene, xylylene glycol, glycerin, trimethylolpropane , one or more types of low-molecular polyols such as pentaerythritol, dialkyl carbonates such as dimethyl carbonate and diethyl carbonate, alkylene carbonates such as ethylene carbonate and propylene carbonate, diphenyl carbonate, dinaphthyl carbonate, dianthryl carbonate, and diphenane. Examples include those obtained from a dealcoholization reaction or dealcoholization reaction with diaryl carbonates such as tolyl carbonate, diindanyl carbonate, and tetrahydronaphthyl carbonate.

Furthermore, polyols obtained by transesterification of polycarbonate polyols, polyester polyols, and low-molecular-weight polyols can also be suitably used.

Examples of the polyolefin polyol include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, and the like.

Acrylic polyols include acrylic esters and/or methacrylic esters (hereinafter referred to as "(meth)acrylic esters"), acrylic acid hydroxy compounds having at least one or more hydroxyl groups in the molecule that can serve as reaction sites, and /Or a methacrylic acid hydroxy compound (hereinafter referred to as "(meth)acrylic acid hydroxy compound") and a polymerization initiator are used to copolymerize an acrylic monomer using thermal energy, ultraviolet rays, or light energy such as an electron beam. I can list things.

Examples of the (meth)acrylic ester include alkyl esters having 1 to 20 carbon atoms. Examples of such (meth)acrylic esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, and (meth)acrylate. ) Alkyl (meth)acrylates such as hexyl acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, and dodecyl (meth)acrylate. Esters; esters of (meth)acrylic acid with alicyclic alcohols such as cyclohexyl (meth)acrylate; (meth)acrylic acid aryl esters such as phenyl (meth)acrylate and benzyl (meth)acrylate; can. Such (meth)acrylic esters may be used alone or in combination of two or more.

Examples of (meth)acrylic acid hydroxy compounds include compounds having at least one hydroxyl group in the molecule that can serve as a reaction site with polyisocyanate, and specifically, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate , 4-hydroxybutyl acrylate, 3-hydroxy-2,2-dimethylpropyl acrylate, pentaerythritol triacrylate, and other hydroxy acrylic compounds. Also included are methacrylic acid hydroxy compounds such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 3-hydroxy-2,2-dimethylpropyl methacrylate, and pentaerythritol trimethacrylate. These (meth)acrylic acid hydroxy compounds may be used alone or in combination of two or more.

Examples of silicone polyols include vinyl group-containing silicone compounds obtained by polymerizing γ-methacryloxypropyltrimethoxysilane, etc., and α,ω-dihydroxypolydimethylsiloxane, α,ω-dihydroxy having at least one terminal hydroxyl group in the molecule. Polysiloxanes such as polydiphenylsiloxane can be mentioned.

Examples of castor oil-based polyols include linear or branched polyester polyols obtained by reacting castor oil fatty acids with polyols. Furthermore, dehydrated castor oil, partially dehydrated castor oil that is partially dehydrated, and hydrogenated castor oil that has hydrogen added thereto can also be used.

Examples of the fluorine-based polyol include linear or branched polyols obtained by a copolymerization reaction of a fluorine-containing monomer and a monomer having a hydroxyl group as an essential component. Here, the fluorine-containing monomer is preferably a fluoroolefin, such as tetrafluoroethylene, chlorotrifluoroethylene, trichlorofluoroethylene, hexafluoropropylene, vinylidene fluoride, vinyl fluoride, trifluoromethyltrifluoroethylene. can be mentioned. Examples of monomers having a hydroxyl group include hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and cyclohexanediol monovinyl ether, hydroxyalkyl allyl ethers such as 2-hydroxyethyl allyl ether, and hydroxyalkyl vinyl crotonate. Monomers having hydroxyl groups such as hydroxyl group-containing vinyl carboxylates or allyl esters may be mentioned.

Further, the polyol preferably has a number of active hydrogen groups (average number of functional groups) in one molecule of 1.9 to 6.0. The average number of functional groups may be 2.0 to 5.0 or 2.0 to 4.0. The number average molecular weight of the polyol is preferably 250 to 50,000. The number average molecular weight of the polyol may be 500 to 40,000, 8000 to 30,000, 1,000 to 20,000, or 1,000 to 10,000.

The chlorine-free polyol component may contain at least one of a polyether polyol having an average functional group number of 2.0 to 4.0 and a castor oil polyol having an average functional group number of 2.0 to 4.0; may contain. The polyether polyol having an average number of functional groups of 2.0 to 4.0 may contain a polyether having an average number of functional groups of 2.0 and a polyether polyol having an average number of functional groups of 4.0. When the chlorine-free polyol component contains a polyether polyol with an average functional group number of 2.0, a polyether polyol with an average functional group number of 4.0, and a castor oil-based polyol with an average functional group number of 2.0 to 4.0, the total amount of polyols Based on (chlorine-containing polyol component + chlorine-free polyol component), 40 to 60% by mass of polyether polyol with an average functional group number of 2.0 and 1.0 to 2.0% by mass of a polyether polyol with an average functional group number of 4.0. 0% by mass, and 8 to 20% by mass of castor oil polyol having an average number of functional groups of 2.0 to 4.0.

As the chlorinated polyol among the chlorine-containing polyol components, any of the chlorinated products of the above-mentioned chlorine-free polyols can be employed. As a method for chlorination, known methods such as addition of epichlorohydrin can be applied.

Examples of the chlorine-containing polyol component include at least one of chlorinated polyether, chlorinated polyester polyol, chlorinated polycarbonate polyol, and chlorinated polymer particle-containing polyol.

Examples of the chlorinated polyether polyol include compounds represented by the following general formula (10). R ¹⁰ is an n-functional organic group, and R ¹¹ is a difunctional organic group, and when a plurality of R ^11s exist, each R ¹¹ may be the same type or a combination of different types. Note that at least one of R ¹⁰ and R ¹¹ (at least one of R ^{11 when a plurality of R 11} exists) has a chlorine atom. n is a number from 1 to 12, and may be 1 to 6, 2 to 6, or 2 to 4, or may be 2. p is a number from 1 to 100, and may be from 1 to 80 or from 1 to 50. Examples of R ¹⁰ and R ¹¹ include hydrocarbon groups (chlorinated hydrocarbon groups when they contain chlorine), and the number of carbon atoms in R ¹⁰ is 1 to 12 or 1 to 6, and the number of carbon atoms in R ¹¹ is 1 to 1. It can be 6 or 1-4.

In the compound represented by the general formula (10), when R ¹⁰ is difunctional (when n is 2), the compound is represented by the following general formula (11). p has the same meaning as above, and the plurality of R ^11s may be the same type or a combination of different types, and R ¹⁰ and/or at least one of the plurality of R ^11s has a chlorine atom. ing.

Examples of the chlorinated polyester polyol include compounds represented by the following general formula (20). R ²⁰ and R ²¹ are bifunctional organic groups, and when a plurality of R ²⁰ and R ²¹ exist, R ²⁰ and R ²¹ may be the same or a combination of different types. Note that at least one of R ²⁰ and R ²¹ (at least one of R ²⁰ and R ²¹ when a plurality of R 20 and R 21 exist) has a chlorine atom. q is a number from 1 to 100, and may be from 1 to 80 or from 1 to 50. Examples of R ²⁰ and R ²¹ include hydrocarbon groups (chlorinated hydrocarbon groups when they contain chlorine), and the carbon numbers of R ²⁰ and R ²¹ are each independently 1 to 30, 1 to 20, or 1 to 20. It can be 12.

Examples of the chlorinated carbonate polyol include compounds represented by the following general formula (30). R ³⁰ is a bifunctional organic group, and a plurality of R ^30s may be the same type or a combination of different types. Note that at least one of the plurality of R ^30s has a chlorine atom. r is a number from 1 to 100, and may be from 1 to 80 or from 1 to 50. Examples of R ³⁰ include hydrocarbon groups (chlorinated hydrocarbon groups when containing chlorine), and the number of carbon atoms in R ³⁰ can be 1 to 30, 1 to 20, or 1 to 12.

Examples of polyols containing chlorinated polymer particles include polyols containing vinyl chloride polymer particles and/or vinyl chloride-unsaturated vinyl copolymer particles. The volume average particle diameter of the chlorinated polymer particles can be 0.05 to 2 μm.

The unsaturated vinyl monomer that forms the vinyl chloride-unsaturated vinyl copolymer may be any monomer that forms a copolymer with vinyl chloride. Examples of unsaturated vinyl include styrenes such as vinyl acetate, styrene, α-methylstyrene, hydroxystyrene, and chlorostyrene, (meth)acrylonitrile compounds such as acrylonitrile and methacrylonitrile, methyl (meth)acrylate, and ethyl (meth)acrylate. ) Acrylic esters, (meth)acrylic esters such as butyl (meth)acrylic ester, (meth)acrylic acid, alkali metal salts of (meth)acrylic acid, (meth)acrylamide, ethylene, propylene, vinylidene chloride, etc. Can be mentioned.
These unsaturated vinyls may be used alone or in combination of two or more.

In order to obtain a polyol containing chlorinated polymer particles, an aqueous dispersion (including an emulsion, latex, or suspension) containing chlorinated polymer particles may be mixed with a polyol, and the resulting mixture may be dehydrated.

As the blowing agent used to obtain the flexible polyurethane foam, a physical blowing agent and/or a chemical blowing agent can be used. Physical blowing agents include chlorofluorocarbons, hydrochlorofluoroolefins, hydrochlorofluorocarbons, hydrofluoroolefins, hydrofluorocarbons, perfluorocarbons, low boiling point halogen hydrocarbons such as methylene chloride, pentane, Examples include hydrocarbons such as cyclopentane, gases such as air, nitrogen, carbon dioxide, and low-temperature liquids. Chemical blowing agents include water, organic acids, inorganic acids such as boric acid, alkali carbonates, cyclic carbonates, dialkyl carbonates, and those that generate gas by reacting with polyurethane raw materials or decomposing by heat etc. can be mentioned. The content of the blowing agent can be 1 to 10 parts by weight, or 1 to 5 parts by weight based on 100 parts by weight of the polyol.

Due to its low ozone depletion potential (ODP) and low global warming potential (GWP), it Chlorofluorocarbons, etc. have zero ODP and small GWP, so HFO-1234zf, E-HFO-1234ze, Z-HFO-1234ze, HFO-1234yf, E-HFO-1255ye, Z-HFO-125ye, E-HFO Hydrofluoroolefins such as -1336mzz, Z-HFO-1336mzz, HFO-1438mzz, hydrofluorocarbons such as HFC-134a, HFC-245, HFC-236, HFC-356, HFC-365mfc, HFC-227ea, etc. bread, Hydrocarbons such as butane, pentane, hexane, cyclopentane, etc., or water are preferred.

Catalysts may be used to obtain flexible polyurethane foams. Examples of the catalyst include tertiary amine compounds and organometallic compounds. The content of the catalyst can be 0.01 to 10 parts by weight, or 0.05 to 5 parts by weight based on 100 parts by weight of polyol.

Examples of tertiary amine compounds include triethylamine, triethylenediamine, N,N-dimethylbenzylamine, N-methylmorpholine, diazabicycloundecene, and the like. Commercially available products can be used, and for example, triethylenediamine (TEDA-L33), bis(dimethylaminoethyl)ether (TOYOCAT-ET), etc. are preferably used.

Examples of organometallic compounds include tin compounds and non-tin compounds. Examples of tin-based compounds include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, tributyltin acetate, and triethyl. Examples include tin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, dioctyltin dilaurylate (also known as DOTDL), tin 2-ethylhexanoate, and the like.

Examples of non-tin compounds include titanium compounds such as dibutyltitanium dichloride, tetrabutyl titanate, and butoxytitanium trichloride, lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate, and 2-ethyl Examples include iron-based materials such as iron hexanoate and iron acetylacetonate, cobalt-based materials such as cobalt benzoate and cobalt 2-ethylhexanoate, zinc-based materials such as zinc naphthenate and zinc 2-ethylhexanoate, and zirconium naphthenate. .

Among the above catalysts, dibutyltin dilaurate (also known as: DBTDL), dioctyltin dilaurate (also known as: DOTDL), tin 2-ethylhexanoate, and the like are preferred in terms of reactivity and hygiene. The above catalysts can be used alone, but two or more types can also be used in combination.

Foam stabilizers may be used to obtain flexible polyurethane foams. By using a foam stabilizer, the cell size of polyurethane foam can be controlled. Generally, polyether/siloxane type organic silicone surfactants having linear, branched, or pendant structures are used, such as polydimethylolsiloxane-polyalkylene oxide block copolymers, vinylsilane-polyalkyl polyol polymers, etc. Can be used. The amount of the foam stabilizer to be added can be 0.1 to 5 parts by weight, or 0.1 to 3 parts by weight, based on 100 parts by weight of the polyol, since the cell structure and size are easily stabilized.

In order to obtain flexible polyurethane foam, various additives such as fillers such as calcium carbonate and barium sulfate, flame retardants, plasticizers, colorants, anti-mold agents, auxiliary agents, crosslinking agents such as polyamines, etc. are added as necessary. It may also be used.

When obtaining a flexible polyurethane foam, the isocyanate index (100 times the molar ratio of NCO to active hydrogen) is preferably 70 to 140, more preferably 70 to 120 as a good range for molding cycles.

If the isocyanate index is less than 70, the closed-cell property of the foam will increase excessively, and if it is higher than 120, unreacted isocyanate will remain for a long time, resulting in an extension of the molding cycle, and foam collapse during foam foaming due to a delay in increasing the molecular weight. There is a possibility that this may occur.

In order to obtain flexible polyurethane foam, the components of the composition for forming flexible polyurethane foam (hereinafter sometimes referred to as "foaming stock solution", containing catalysts, foam stabilizers, etc. as appropriate) are thoroughly mixed. , reaction and foaming.

Specifically, the foaming stock solution is injected into a mold and then foamed and cured to form a flexible polyurethane molded foam (hereinafter sometimes referred to as "flexible molded foam"). The mixed solution is poured into a foaming container or continuously. Alternatively, a method can be adopted in which the polyurethane foam is supplied onto a belt conveyor and foamed to form a flexible polyurethane slab foam (hereinafter sometimes referred to as "flexible slab foam").

In the production of flexible molded foam, the temperature of the mold when the foaming stock solution is injected into the mold is usually 30 to 80°C, preferably 45 to 70°C. If the mold temperature when injecting the foaming stock solution into the mold is less than 30°C, the reaction rate may slow down and the production cycle may be extended. On the other hand, if it is higher than 80°C, the reaction between polyol and isocyanate may be delayed. On the other hand, if the reaction between water and isocyanate is excessively accelerated, the foam may collapse during foaming.

The curing time when foaming and curing the foaming stock solution is preferably 10 minutes or less, more preferably 7 minutes or less, considering the production cycle of general flexible molded foams.

When producing a flexible molded foam, the above-mentioned components can be mixed using a high-pressure foaming machine, a low-pressure foaming machine, etc., as in the case of ordinary flexible molded foams.

It is preferable to mix the polyisocyanate and the polyol immediately before foaming. Other components can be mixed in advance with the polyisocyanate or polyol to the extent that they do not affect the storage stability or reactivity of the raw materials over time. These mixtures may be used immediately after mixing, or may be stored and then used in the required amount as appropriate. In the case of a foaming device that can simultaneously introduce more than two components into the mixing section, polyols, blowing agents, polyisocyanates, catalysts, foam stabilizers, foam breakers, etc. can also be introduced individually into the mixing section.

Further, the mixing method may be either dynamic mixing in which mixing is carried out in the mixing chamber of the machine head of the foaming machine, or static mixing in which mixing is carried out in the liquid feeding pipe, or both may be used in combination. Mixing of a gaseous component such as a physical foaming agent and a liquid component is often performed by static mixing, and mixing of components that can be stably stored as a liquid is often performed by dynamic mixing. The foaming device is preferably a high-pressure foaming device that does not require solvent cleaning of the mixing section.

The liquid mixture obtained by such mixing is injected into a mold, foamed and hardened, and then demolded. In order to perform demolding smoothly, it is also preferable to apply a mold release agent to the mold in advance. As the mold release agent to be used, a mold release agent commonly used in the field of molding processing may be used.

Furthermore, in the production of flexible molded foam, the surface of the foam can be coated with a film by integral molding for the purpose of enhancing the sound absorption effect of a specific frequency. A sound absorbing film absorbs sound that attempts to pass through the film from the outside by converting relatively low frequency sound of 1000 to 2000 Hz into vibration energy.

Integrated mold molding is a method in which a film is placed in advance in at least one of the lower mold or upper mold in a shape that follows the inner surface shape, the mixed liquid is injected into the mold, and the mold is removed after foaming and hardening. be. At least one film is placed in the order of the film and the flexible polyurethane foam against the sound source, but may also be placed on the opposite side of the sound source in order to increase the sound insulation rate.

As the film laminated on the flexible polyurethane foam, a non-breathable resin film is preferably used. Examples of the resin include polyurethane resin, acrylic resin, polyethylene resin, polypropylene resin, vinyl chloride resin, EVA resin, PBT resin, silicone rubber, 6-nylon, 6,6-nylon, 11-nylon, 12-nylon, etc. Examples include polyamide resin.

The thickness of the film is preferably 0.1 to 250 μm. If the thickness of the film is less than 0.1 μm, the moldability during molding may deteriorate, and if it exceeds 250 μm, the sound absorption performance may deteriorate. Further, the density of the film is preferably 0.8 to 1.8 g/cm ³ . If the film density is less than 0.8 g/cm ³ , a sufficient sound absorption effect may not be obtained in the low frequency range, and if it exceeds the upper limit, the weight of the sound absorbing material will increase.

As a method for forming a film layer on the surface of flexible polyurethane foam, it is also possible to perform in-mold coat molding, in which the polyurethane foam is molded after applying an in-mold coat paint to at least one of the lower mold or upper mold in advance. .

The paint for in-mold coating can suitably be used in both water-based and solvent-based systems, and may be either a one-component curing type or a two-component curing type. Examples of the resin for in-mold coating paints include known paints such as polyurethane resins, acrylic resins, and polyester resins, among which polyurethane resins are preferred, and furthermore, from the viewpoint of being able to increase the softening temperature. An aqueous polyurethane resin emulsion using a polyol component having a carbonate skeleton is preferred. The polyol component having a carbonate skeleton may contain an ester group other than the carbonate skeleton, and an aqueous polyurethane resin emulsion using a polyol component having a carbonate skeleton, and an aqueous polyurethane resin emulsion using a polyol component having an ester group. It may be a mixture of. The average number of functional groups of the polyol component having a carbonate skeleton is preferably 2.1 or more. When the average number of functional groups is less than 2.1, the heat resistance of the resulting film layer is likely to be impaired.

The product after demolding can be used as is, but the cell membrane of the foam may be destroyed under compression or reduced pressure by a known method to stabilize the appearance and dimensions of the product thereafter.

After demolding, the soft molded foam is subjected to needle punching or hot needle processing on the surface skin layer or laminated film in order to effectively input sound wave energy into the internal porous layer and increase the sound absorption effect on the high frequency side. It can be used after being subjected to hole-opening treatment such as laser irradiation. The porosity is preferably 0 to 2.0%. If the porosity exceeds 2.0%, the sound absorption effect on the low frequency side may be reduced. Furthermore, when the porosity ratio exceeds 0%, the average pore diameter is preferably 300 μm to 1000 μm, more preferably 300 μm to 900 μm. If the average opening diameter is less than 300 μm, there is a risk that the hole will be blocked by burrs generated during drilling, and if it exceeds 1000 μm, there is a risk that the sound absorption effect on the low frequency side will decrease.

By the above-described manufacturing method of flexible polyurethane foam, the thickness is 5.0 to 50 mm, the density (calculated as apparent density) is 25 to 200 kg/m ³ , the C hardness of the foam test piece is 0.1 to 20 points, and the ventilation To obtain a flexible polyurethane foam having a sound absorption coefficient of 0.1 to 30 cm ³ /cm ² /sec and an average sound absorption coefficient of 0.35 or more at 500 Hz, 630 Hz, 800 Hz, 1000 Hz and 1250 Hz, in accordance with JIS A1405-2:2007. be able to. If the average value of the sound absorption coefficient is 0.35 or more, a practically sufficient sound absorption effect will be exhibited.

Regarding the flexible polyurethane foam, the apparent density according to JIS K-6400:2004 is preferably 25 to 200 kg/m ³ , ⁵⁰ to 180 kg/m 3 , 80 to 175 kg/m ³ , or 110 to 150 kg/m 3 It may be ³ . C hardness measured using a rubber hardness meter (Asker C type) described in JIS K7312 is preferably 0.1 to 20 points, 0.5 to 15 points, 0.8 to 12 points, or It may be 1 to 10 points.

In addition, regarding the flexible polyurethane foam, the air permeability according to JIS K6400-7:2012 is preferably 0.1 to 30 cm ³ /cm ² /sec, 0.1 to 10 cm ³ /cm ² /sec, 0 .1 to 5 cm ³ /cm ² /sec, or 0.1 ^{to 2 cm 3} /cm ² /sec. Based on JIS A1405-2:2007, the average value of sound absorption coefficient for 500Hz, 630Hz, 800Hz, 1000Hz and 1250Hz is 0.35-1.00, 0.35-0.80, 0.35-0.70 , 0.35 to 0.60, or 0.35 to 0.50.

Flexible polyurethane foam has a maximum and minimum loss tangent (tan δ) value between -20°C and 100°C, determined by dynamic viscoelasticity measurement in compression mode at a frequency of 100Hz and a heating rate of 2°C/min. The difference between them must be within 0.30. Note that a test piece having a width of 10 mm, a length of 10 mm, and a thickness of 10 mm can be used for measuring the loss tangent (tan δ). The difference between the maximum value and the minimum value between -20°C and 100°C measured under the above conditions may be 0 to 0.30, 0.10 to 0.28, or 0.10 to 0.26. .

The complex elastic modulus of the flexible polyurethane foam at 25° C. determined by dynamic viscoelasticity measurement in compression mode at a frequency of 100 Hz and a heating rate of 2° C./min may be 0.5 or less. Note that a test piece having a shape of 10 mm in width, 10 mm in length, and 10 mm in thickness can be used for measuring the complex modulus of elasticity. The complex modulus measured under the above conditions may be 0.1 to 0.5, 0.2 to 0.5, or 0.3 to 0.5.

The value of the loss tangent (tan δ) determined by dynamic viscoelasticity measurement at 100 Hz, heating rate of 2°C/min, and compression mode is arbitrary, but between -20°C and 100°C, for example, from 0.20 to 0.55, 0.20 to 0.50.

EXAMPLES Hereinafter, the present invention will be explained with reference to examples, but the present invention is not limited to the following examples.

[Synthesis of chlorinated polyol]
Chlorinated polyol 1:
Tetra-n-butylammonium bromide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and triisopropoxyaluminum are mixed into aliphatic polyester polyol with a molecular weight of 1000 (manufactured by Kuraray Co., Ltd., product name: Kuraray Polyol P-1010, adipic acid type). By thoroughly dehydrating and removing the solvent, and adding epichlorohydrin (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.), a bifunctional, chlorinated polyol 1 having a molecular weight of 2,000 was prepared. The chlorine concentration of chlorinated polyol 1 was 19%. Note that the chlorine concentration was calculated according to the following formula.
Chlorine concentration (%) = (molecular weight of chlorinated polyol - molecular weight of initiator) x (chlorine atomic weight ÷ molar mass of epichlorohydrin) ÷ molecular weight of chlorinated polyol x 100

Chlorinated polyol 2:
Tetra-n-butylammonium bromide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and triisopropoxyaluminum are mixed into polycarbonate polyol (manufactured by Kuraray Co., Ltd., trade name: Kuraray Polyol C-1090) with a molecular weight of 1000, and then dehydrated and solvent removed. was carried out sufficiently, and epichlorohydrin (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) was added to prepare a bifunctional, chlorinated polyol 2 having a molecular weight of 2,000. The chlorine concentration of chlorinated polyol 2 was 19%. Note that the chlorine concentration was measured in the same manner as in the case of chlorinated polyol 1.

Polyol containing chlorinated polymer particles:
650 g of polyether polyol (manufactured by AGC, trade name: EL-820) with a molecular weight of 4900 and 350 g of vinyl chloride polymer latex (average volume particle diameter: 1.2 μm) were placed in a disper mixer (PRIMIX, manufactured by Primix), and the mixture was heated at 2000/min. The mixture was mixed by rotation for 3 minutes at a room temperature of 25° C. to prepare a polyol containing chlorinated polymer particles having a chlorinated vinyl polymer content of 35% by mass. The chlorine concentration in the polyol containing chlorinated polymer particles was 20%.

[Polyol composition]
Weigh out the ingredients listed in "Second Liquid" in Table 1 into a polypropylene cup (1 L), and mix at 1400 rpm for 20 minutes at room temperature of 25°C using a small high-speed stirrer (PRIMIX manufactured by PRIMIX). , polyol compositions P-1 to P-9 were obtained.

[Foam molding]
Isocyanate 1 was added to polyol compositions P-1 to P-9 so that the isocyanate index would be as shown in Table 1, and the mixture was stirred at 7,000 revolutions per minute using a small high-speed stirrer (PRIMIX manufactured by PRIMIX). The mixture was mixed for a second to prepare a foaming stock solution. Immediately after preparing the foaming stock solution, it was injected into a mold to foam a flexible polyurethane foam. Thereafter, it was taken out from the mold and the physical properties of the obtained flexible polyurethane foam were measured.
[Foaming conditions]
Mold temperature: 60-70℃
Mold shape: 200mm x 200mm x 10mm
Mold material: Aluminum Cure time: 5 minutes

In addition, "Isocyanate index" in Table 1 refers to the molar ratio ( NCO/active hydrogen).

The raw materials used in Table 1 are as follows.
Isocyanate 1:
Diphenylmethane diisocyanate (MDI) content 76% by mass, polymethylene polyphenylene polyisocyanate (polymeric MDI, P-MDI) content 24% by mass, MDI isomer (2,4'-MDI and 2,2'-MDI) content 38% by mass polyisocyanate, "CEF-549" manufactured by Tosoh Corporation
Polyol 1:
Polyoxypropylene glycol with average number of functional groups = 2 and number average molecular weight = 1000, "SANNIX PP-1000" manufactured by Sanyo Chemical Industries, Ltd.
Polyol 2:
Castor oil-based polyol with average functional group number = 2.7 and hydroxyl value = 160 (mgKOH/g), "URIC H24" manufactured by Ito Oil Co., Ltd.
Polyol 3:
The above chlorinated polyol 1 was used.
Polyol 4:
The above chlorinated polyol 2 was used.
Polyol 5:
The above polyol containing chlorinated polymer particles was used.
Polyol 6:
Average number of functional groups = 4.0, hydroxyl value = 28 (mgKOH/g), polyoxyethylene polyoxypropylene polyol with 80% by mass of oxyethylene units, "NEF-024" manufactured by Tosoh Corporation
Catalyst 1:
Amine catalyst, “TEDA-L33” manufactured by Tosoh Corporation
Catalyst 2:
Amine catalyst, “TOYOCAT-ET” manufactured by Tosoh Corporation
Foam stabilizer 1:
Silicone foam stabilizer "Y10366J" manufactured by MOMENTIVE

Examples 1 to 6 and Comparative Examples 1 to 3 were evaluated based on the following evaluation method, and the results are shown in Table 2.
[Evaluation method]
Loss tangent (tanδ):
The flexible polyurethane foam obtained by the above foam molding was cut into a piece having a width of 10 mm, a length of 10 mm, and a thickness of 10 mm. Using a dynamic viscoelasticity measuring device Rheogel E-4000 manufactured by UBM, measurements were carried out under the conditions of measurement temperature -100°C to 100°C, heating rate 2°C/min, frequency 100Hz, and compression mode. The complex modulus (=(storage modulus ² + loss modulus ² ) ^1/2 and loss tangent (tan δ) were measured. From the measurement data, the maximum value of loss tangent (tan δ) between -20°C and 100°C The minimum value was determined, and the difference between the maximum value and the minimum value was calculated.The flexible polyurethane foams of Examples 1, 2, 3, 4, 5, 6 and Comparative Examples 1 and 2 were measured between -20°C and 100°C. 1, 2, 3, 4, 5, 6, 7 and 8, respectively.
density:
It was obtained as the apparent density of the entire foam (unit: kg/m ³ ) measured in accordance with JIS K-6400:2004. The weight (W) of a rectangular parallelepiped flexible polyurethane foam (length 200 mm x width 200 mm x thickness 10 mm) was measured, and then the volume (V) was determined from the length, width, and thickness of the rectangular parallelepiped, and the density (ρ) was calculated. .
C hardness:
It was measured using a rubber hardness meter (Asker C type) described in JIS K7312.
Air permeability:
It was measured by the method described in JIS K6400.
Sound absorption coefficient:
Based on the method described in JIS A1405-2:2007, the normal incidence sound absorption coefficient at 500 Hz, 630 Hz, 800 Hz, 1000 Hz, and 1250 Hz was measured using a 4206 type acoustic tube manufactured by Brüel & Kjær Japan. The sound absorption coefficient was measured by placing a urethane foam with a diameter of 28.8 mm and a thickness of 10 mm so that the lower molding surface of the mold faced the sound source side, and with no air layer provided behind the urethane foam. Further, the measurement was performed at a temperature of 20° C., a humidity of 50% RH, and 1 atm.
Formability:
A moldability rating of "○" indicates that the flexible polyurethane foam can be molded without collapse, where the urethane foam sinks significantly after reaching its maximum height, or with shrinkage of the generated urethane foam immediately after foaming or after curing. An evaluation of "x" means that a phenomenon such as collapse or shrinkage occurred in the urethane foam, or that poor mixing occurred.
Complex modulus:
The flexible polyurethane foam obtained by the above foam molding was cut into a piece having a width of 10 mm, a length of 10 mm, and a thickness of 10 mm. Using a dynamic viscoelasticity measuring device Rheogel E-4000 manufactured by UBM, measurements were carried out under the conditions of measurement temperature -100°C to 100°C, heating rate 2°C/min, frequency 100Hz, and compression mode. The complex modulus of elasticity (=(storage modulus ² + loss modulus ² ) ^1/2 was calculated.

Claims (8)

The difference between the maximum and minimum values of the loss tangent (tan δ) obtained by dynamic viscoelasticity measurement in compression mode at a frequency of 100 Hz and a heating rate of 2°C/min between -20°C and 100°C is 0. Flexible polyurethane foam with a rating of 30 or less. The flexible polyurethane foam according to claim 1, having a complex modulus of elasticity of 0.5 or less at 25°C determined by dynamic viscoelasticity measurement in compression mode at a frequency of 100Hz and a heating rate of 2°C/min. consisting of a reactant of a composition comprising a polyisocyanate, a polyol and a blowing agent;
The flexible polyurethane foam according to claim 1 or 2, wherein the polyol contains at least one selected from the group consisting of a chlorinated polymer particle-containing polyol and a chlorinated polyol. The flexible polyurethane foam according to claim 3, wherein the chlorinated polyol contains at least one of a chlorinated polyester polyol and a chlorinated polycarbonate polyol. The flexible polyurethane foam according to claim 3 or 4, further comprising a polyether polyol and/or a castor oil polyol having an average functional group number of 2.0 to 4.0 as the polyol. The polyisocyanate contains an MDI polyisocyanate composed of monomeric MDI and polymeric MDI,
The content of the monomeric MDI is 50 to 85% by mass with respect to the total amount of the monomeric MDI and the polymeric MDI,
The monomeric MDI is composed of 4,4'-MDI and 2,2'-MDI and 2,4'-MDI, which are isomers of 4,4'-MDI, and the total content of the isomers is as follows. Flexible polyurethane foam according to any one of claims 3 to 5, which is 10 to 50% by weight based on monomeric MDI. The average sound absorption coefficient of 500Hz, 630Hz, 800Hz, 1000Hz and 1250Hz is 0.35 in accordance with JIS A1405-2:2007 at a thickness of 10mm measured at a temperature of 20℃, humidity of 50% RH, and 1 atm. The flexible polyurethane foam according to any one of claims 1 to 6, which is the above. The soft polyurethane according to any one of claims 1 to 7, which has a density of 25 to 200 kg/m ³ , a C hardness of 0.1 to 20 points, and an air permeability of 0.1 to 30 cm ³ /cm ² /sec. form.