Composition for molding flexible polyurethane foam

Abstract

To provide a composition for molding soft polyurethane foam that can be used as a sound-absorbing material to render the substrate thin, and has high sound absorption performance in a wide range of frequencies, and a soft polyurethane foam including the composition.SOLUTION: A composition for molding soft polyurethane foam is composed of a polyol component (A) and a polyisocyanate component (B). The polyol component (A) includes a catalyst (C), a foam stabilizer (D), and a foamer (E). At least one of the polyol component (A) and the polyisocyanate component (B) includes a foam breaker (F). The content of the foam breaker is 0.1-7.5 mass% relative to the total amount of the composition for molding soft polyurethane foam.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a composition for molding flexible polyurethane foam and a flexible polyurethane foam using the composition. [Background technology]

[0002] Flexible polyurethane foam is used in a wide range of applications, including household goods, automotive interior materials, clothing, sports and leisure goods, medical materials, and civil engineering and construction materials. Within these application areas, there is a particular need for further noise reduction through improved performance of soundproofing materials such as sound-absorbing and sound-insulating materials, especially in transportation vehicles such as automobiles and buildings such as houses. In the automotive sector in particular, with the application of external noise regulations and the prospect of stricter regulations in the future, reducing engine noise transmission and tire noise radiation is an urgent issue, leading to increased demand for sound-absorbing materials. While increasing the thickness of the base material can relatively easily improve sound absorption and vibration absorption performance, there are concerns that a thicker base material may prevent sufficient space from being secured in transportation vehicles or buildings. Therefore, it is necessary to improve sound absorption performance while simultaneously reducing the thickness of the base material.

[0003] Various efforts have been made to improve this sound absorption performance. For example, Patent Document 1 describes a method for improving sound absorption in the 1000Hz-2000Hz range by increasing the cell diameter of rigid foam as a soundproofing material for a dashboard panel. However, because the base material is rigid foam, there is a problem that its shape does not conform well when attached to a vehicle, and it is difficult to restore its shape when compressed, thus limiting the areas in which it can be used. In addition, since the average sound absorption rate in the 1000-2000Hz range is 45% or more when the thickness of the base material is 15mm, it cannot be said that the thinning of the base material and the sound absorption performance are sufficient. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2006-017983 [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention has been made in view of the above-mentioned background art, and aims to provide a flexible polyurethane foam molding composition that has a thin substrate thickness and high sound absorption performance over a wide frequency range when used as a sound-absorbing material, and a flexible polyurethane foam using the composition. [Means for solving the problem]

[0006] In other words, the present invention includes the embodiments shown below.

[0007] [1] A flexible polyurethane foam molding composition comprising a polyol component (A) and a polyisocyanate component (B), wherein the polyol component (A) comprises a catalyst (C), a foam stabilizer (D), and a blowing agent (E), and at least one of the polyol component (A) or the polyisocyanate component (B) contains a foam breaker (F), and the content of the foam breaker is 0.1 to 7.5% by mass of the total amount of the flexible polyurethane foam molding composition.

[0008] [2] The flexible polyurethane foam molding composition according to [1] above, characterized in that the antifoaming agent (F) is a silicone oil and the number average molecular weight of the polysiloxane component contained in the silicone oil is 10,000 to 50,000.

[0009] [3] The flexible polyurethane foam molding composition according to [1] or [2] above, characterized in that the antifoaming agent (F) is included in the polyol component (A).

[0010] [4] A flexible polyurethane foam molding composition according to any one of [1] to [3] above, characterized in that the polyisocyanate component (B) contains diphenylmethane diisocyanate in an amount of 50 to 85% by mass, and the total amount of 2,2'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate contained in the diphenylmethane diisocyanate is 10 to 50% by mass relative to the total amount of the diphenylmethane diisocyanate.

[0011] [5] A flexible polyurethane foam obtained by reacting and foaming a flexible polyurethane foam molding composition described in any of [1] to [4] above.

[0012] [6] The flexible polyurethane foam described in [5] above, characterized in that, in a sound absorption coefficient measurement method compliant with JIS A1405-2:2007, the simple average value of the sound absorption coefficient in the frequency range of 1000Hz to 3500Hz is 0.6 or higher.

[0013] [7] Density of 25-200 kg / m³ 3 Furthermore, the C hardness of the foam test specimen is 5.0 to 85, and the air permeability is 0.1 to 100 cm. 3 / cm 2 The flexible polyurethane foam according to [5] or [6] above, characterized in that it is / sec.

[0014] [8] The flexible polyurethane foam according to any one of [5] to [7] above, characterized in that the average cell diameter of the flexible polyurethane foam is 2000 μm or more, and the area ratio occupied by cells with a diameter of 5000 μm or more is 20% or more.

[0015] [9] A flexible polyurethane foam according to any one of [5] to [8] above, characterized in that the thickness of the thinnest part is 5.0 to 50 mm.

[0016]

[10] A foamed laminate comprising the soft polyurethane foam and the film according to any one of [5] to [9] above, wherein at least one film is arranged in the order of the film and the soft polyurethane foam with respect to a sound source.

[0017]

[11] The foamed laminate according to

[10] above, wherein the film is coated on the foam surface by integral molding with the soft polyurethane foam.

[0018]

[12] The foamed laminate according to

[10] or

[11] above, wherein the film is a polyurethane resin film.

[0019]

[13] The foamed laminate according to

[12] above, wherein the polyurethane resin film is obtained from an aqueous polyurethane resin emulsion.

[0020]

[14] The foamed laminate according to

[13] above, wherein the polyol component used in the aqueous polyurethane resin emulsion has a carbonate skeleton.

[0021]

[15] The foamed laminate according to

[14] above, wherein the average functionality number of the polyol component having a carbonate skeleton is 2.1 or more.

[0022]

[16] The foamed laminate according to any one of

[10] to

[12] above, wherein the film has a thickness of 0.1 to 250 μm, an open cell ratio of 0 to 2.0%, and an average open cell diameter of 300 μm to 1000 μm when the open cell ratio exceeds 0%.

Effect of the Invention

[0023] By using the composition for forming a soft polyurethane foam of the present invention, it becomes possible to obtain a soft polyurethane foam that has a thin base material thickness and high sound absorption performance in a wide frequency range when used as a sound absorption material.

Mode for Carrying Out the Invention

[0024] The present invention will be described in further detail.

[0025] The flexible polyurethane foam molding composition of the present invention comprises the following polyol component (A), polyisocyanate component (B), catalyst (C), foam stabilizer (D), blowing agent (E), and foam breaker (F).

[0026] The polyol component (A) is formed by polyaddition with the polyisocyanate component (B) to form polyurethane, and in the present invention, it is preferable that it be at least one selected from the group consisting of polyether polyols and polyester polyols. Furthermore, a number average molecular weight of 1,000 to 10,000 is preferable, 3,000 to 8,000 is more preferable, and 4,000 to 8,000 is most preferable. In addition, a nominal number of functional groups of 2 or more is even more preferable. If the number average molecular weight is below the lower limit, the resulting foam tends to lack flexibility, and if it exceeds the upper limit, the hardness of the foam tends to decrease. Also, if the nominal number of functional groups is less than 2, the rebound modulus of the foam decreases significantly, and problems occur such as the foam not returning to its original shape when compressed. Note that the nominal number of functional groups refers to the theoretical average number of functional groups (number of active hydrogen atoms per molecule) assuming that no side reactions occur during the polymerization reaction of the polyol.

[0027] Examples of polyether polyols include polypropylene ether polyol, polyethylene polypropylene ether polyol (hereinafter referred to as PPG), and polytetramethylene ether glycol (hereinafter referred to as PTG). Examples of polyester polyols include polycondensation type polyester polyols consisting of adipic acid and a diol, and lactone-based polyester polyols such as polycaprolactone polyol.

[0028] In the present invention, from the viewpoint of improving the heat resistance of the foam, at least one polyol selected from the group consisting of castor oil and castor oil-modified polyols can be used in combination with the polyol component (A). Examples of such at least one polyol selected from the group consisting of castor oil and castor oil-modified polyols include derivatives of castor oil such as refined castor oil, semi-refined castor oil, unrefined castor oil, and hydrogenated castor oil.

[0029] Furthermore, in the present invention, it is preferable that the polyol component (A) contains a polyether polyol having polyoxyalkylene chains made of a copolymer of oxyethylene and oxypropylene, for the purpose of promoting the interconnection of the flexible polyurethane foam. The number average molecular weight is preferably 3,000 to 8,000, and the nominal number of functional groups is preferably 2 to 4. Moreover, it is preferable that the oxyethylene units in the polyether polyol be 60 to 90% by mass, and more preferably 60 to 80% by mass. By setting the oxyethylene units to 60 to 90% by mass, the durability of the foam can be improved. Also, from the viewpoint of storage stability at low temperatures, it is preferable that the copolymer made of oxyethylene and oxypropylene is a random copolymer.

[0030] The amount of polyether polyol added is preferably 0.5 to 5.0% by mass relative to the polyol component (A). Below the lower limit, the moldability of the foam may deteriorate, and above the upper limit, the elongation of the foam may decrease.

[0031] The polyol component (A) of the present invention may be used in combination with a polymer polyol obtained by polymerizing vinyl monomers in a polyol using a conventional method for the purpose of adjusting hardness. Examples of such polymer polyols include those obtained by polymerizing vinyl monomers in a polyalkylene polyol such as PPG in the presence of a radical initiator and stably dispersing them. Examples of vinyl monomers include acrylonitrile, styrene, vinylidene chloride, hydroxyalkyl methacrylate, and alkyl methacrylate, with acrylonitrile and styrene being preferred. Examples of such polymer polyols include EL-910 and EL-923 from AGC Corporation, and FA-728R from Sanyo Chemical Industries Ltd.

[0032] In the present invention, the polyisocyanate component (B) preferably uses diphenylmethane diisocyanates (hereinafter referred to as MDI), such as 4,4'-diphenylmethane diisocyanate (hereinafter referred to as 4,4'-MDI), 2,4'-diphenylmethane diisocyanate (hereinafter referred to as 2,4'-MDI), 2,2'-diphenylmethane diisocyanate (hereinafter referred to as 2,2'-MDI), and polyphenylene polymethylene polyisocyanate (hereinafter referred to as P-MDI) as the isocyanate source. In the present invention, various modified forms such as the above-mentioned MDI, mixtures of MDI and P-MDI, urethane modified forms, urea modified forms, allophanate modified forms, nurate modified forms, and biuret modified forms can also be used.

[0033] The MDI content of the polyisocyanate component (B) according to the present invention is preferably in the range of 50 to 85% by mass. If the MDI content exceeds 85% by mass, the storage stability of the resulting polyisocyanate composition at low temperatures and the durability of the resulting flexible foam may decrease. On the other hand, if it is less than 50% by mass, the elongation of the flexible polyurethane foam decreases as the crosslinking density increases, making it difficult to obtain sufficient foam strength.

[0034] Furthermore, the sum of the content of 2,2'-MDI and the content of 2,4'-MDI relative to the total amount of MDI (hereinafter referred to as the isomer content) is preferably 10 to 50% by mass.

[0035] If the content of 2,2'-MDI and 2,4'-MDI relative to the total amount of MDI in the present invention is less than 10% by mass, the storage stability of the resulting polyisocyanate composition at low temperatures may be impaired, and it may be necessary to keep the isocyanate storage area, piping, and foam molding machine constantly heated. In addition, the molding stability of the flexible polyurethane foam may be impaired, and foam collapse during foaming may occur. On the other hand, if it exceeds 50% by mass, the reactivity decreases, which may lead to problems such as an extended molding cycle, a higher degree of foam closure, and shrinkage after molding.

[0036] As catalyst (C), various urethane catalysts known in the art can be used, for example, triethylamine, tripropylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine, dimethylbenzylamine, N,N,N',N'-tetramethylhexamethylenediamine, N,N,N',N',N''-pentamethyldiethylenetriamine, bis-(2-dimethylaminoethyl) ether, triethylenediamine, 1,8-diaza-bicyclo[5.4.0]undecene-7, 1,2-dimethylimidazole, dimethylethanolamine, N,N-dimethyl-N-hexanolamine, as well as organic salts thereof, organometallic compounds such as stanus octoate and zinc naphthenate. Amine catalysts having active hydrogen, such as N,N-dimethylethanolamine and N,N-diethylethanolamine, are also preferred.

[0037] The amount of catalyst added is preferably 0.01 to 10% by mass relative to the polyol component (A). Below the lower limit, curing is likely to be insufficient, and above the upper limit, moldability may deteriorate.

[0038] As the foam stabilizer (D), a conventional surfactant can be used, and a silicone-based surfactant is preferably used. Examples include SZ-1327, SZ-1325, SZ-1336, SZ-3601 from Dow-Toray, Y-10366J, L-5309J from Momentive, and B-8724LF2, B-8715LF2 from Evonik. The amount of these foam stabilizers added is preferably 0.1 to 3.0% by mass relative to the polyol component (A).

[0039] The blowing agent (E) is primarily water. Water reacts with isocyanate groups to form high-hardness urea groups and generates carbon dioxide, thereby causing foaming. Alternatively, any additional blowing agent may be used in addition to water. For example, small amounts of low-boiling point organic compounds such as cyclopentane or isopentane may be used in combination, or air, nitrogen gas, or liquefied carbon dioxide can be mixed and dissolved into the stock solution using a gas loading device to induce foaming. The amount of blowing agent added is usually 0.5 to 10% by mass relative to the polyol composition, but the apparent density is 25 kg / m³. 3 When obtaining a low-density flexible polyurethane foam, the density is preferably 4.0 to 7.0% by mass, and more preferably 4.0 to 6.5% by mass. Exceeding the upper limit may make foaming unstable, and below the lower limit may prevent the density of the foam from being sufficiently reduced.

[0040] The defoaming agent (F) in this invention is used for the purpose of coarsening the cells of the flexible polyurethane foam. By coarsening the cells, a resonator-type sound absorption mechanism is created within the flexible polyurethane foam, making it possible to enhance the sound absorption effect at specific frequencies. Examples of components of the defoaming agent (F) include silicone-based, oil-based, fatty acid-based, fatty acid ester-based, and phosphate ester-based defoaming agents, as well as defoaming agents in which part of the structure has been modified. These may be contained individually or in combination of two or more types. Furthermore, if two or more types are contained, any combination of silicone-based, alcohol-based, ether-based, polyol-based, metal soap-based, nonionic surfactant-based, oil-based, fatty acid-based, fatty acid ester-based, and phosphate ester-based defoaming agent components may be used. In addition, the defoaming agent component is particularly preferably a silicone-based defoaming agent. Examples of silicone-based defoaming agents include oil-type, oil compound-type, solution-type, emulsion-type, self-emulsifying-type, and powder-type, all of which can be suitably used. Silicone-based foaming agents, like the silicone-based foam stabilizers described above, have a polysiloxane structure, but differ in that the polysiloxane chain is relatively long to exhibit foaming properties, and they are highly insoluble in the polyol component (A) or polyisocyanate component (B). The number average molecular weight of the polysiloxane component is preferably 10,000 to 50,000, and more preferably 10,000 to 30,000. If the number average molecular weight is less than 10,000, the foaming effect may be difficult to obtain, and if the number average molecular weight exceeds the upper limit, the dispersibility of the foaming agent may decrease and separation may occur.

[0041] Examples of silicone-based antifoaming agents include dimethyl silicone oil [(CH3)3Si-[OSi(CH3)2]nO-Si(CH3)3], methylphenyl silicone oil [(CH3)3Si-[OSi(CH3)2]m-[OSi(CH3)(C6H5)]nO-Si(CH3)3, (CH3)3Si-[OSi(CH3)2]m-[OSi(C6H5)2]nO-Si(CH3)3, etc.], and methyl hydrogen silicone oil [(CH3)3Si-[OSi(CH3)2]m-[OSi(CH3)(H)]nO-Si(CH3)3, etc.].

[0042] The content of the defoaming agent (F) is preferably 0.1 to 7.5% by mass, and more preferably 0.1 to 7.0% by mass, relative to the total amount of the flexible polyurethane foam molding composition. If the content is less than 0.1% by mass, the coarsening of the cells may be insufficient, and sufficient sound absorption characteristics may not be obtained. If the content exceeds 7.5% by mass, foaming may become unstable.

[0043] The flexible polyurethane foam molding composition of the present invention may contain, as needed, fillers such as calcium carbonate and barium sulfate, as well as various known additives and auxiliary agents such as flame retardants, plasticizers, colorants, and antifungal agents.

[0044] In the present invention, from the above-mentioned flexible polyurethane foam molding composition, the thinnest part thickness is 5.0 to 50 mm and the density is 25 to 200 kg / m³. 3 Furthermore, the C hardness of the foam test specimen is 5.0 to 85, the simple average value of the sound absorption coefficient from 1000Hz to 3500Hz (hereinafter referred to as the average sound absorption coefficient) is 0.6 or higher, and the air permeability is 0.1 to 100 cm. 3 / cm 2 A flexible polyurethane foam with a sound absorption coefficient of / sec can be suitably obtained. Here, the average sound absorption coefficient refers to the simple average value of the normal incidence sound absorption coefficient at 1000Hz, 1250Hz, 1600Hz, 2000Hz, 2500Hz, 3150Hz, and 3500Hz, measured according to the method described in JIS A1405-2:2007.

[0045] Next, the method for producing the flexible polyurethane foam of the present invention will be described.

[0046] The flexible polyurethane foam of the present invention can be produced by reacting and foaming a mixture of a polyol component (A), a polyisocyanate component (B), a catalyst (C), a foam stabilizer (D), a blowing agent (E), and a foam defoamer (F). From the viewpoint of ensuring dispersion stability, it is preferable to add the foam defoamer (F) to the polyol component (A).

[0047] The NCO index (the molar ratio of NCO to active hydrogen multiplied by 100) during the mixing and foaming of all isocyanate groups in the polyisocyanate composition of the present invention and all active hydrogen groups in an active hydrogen group-containing compound containing water is preferably 70 to 140, and more preferably 70 to 120 as a good range for molding cycles.

[0048] If the NCO INDEX is below 70, the foam's cellulite may become excessively high. If it is above 120, there is a risk of prolonged molding cycles due to the prolonged presence of unreacted isocyanates, and foam collapse during foaming due to delayed high molecular weight formation.

[0049] As a method for manufacturing flexible polyurethane foam, methods such as injecting a foaming stock solution, which is a mixture of the polyol component (A), polyisocyanate component (B), catalyst (C), foam stabilizer (D), foaming agent (E), and foam-defrosting agent (F), into a mold and then foaming and curing it, can be used to manufacture flexible polyurethane molded foam (hereinafter referred to as flexible molded foam), and in supplying the mixture solution to a foaming container or a belt conveyor and foaming it, can be used to manufacture flexible polyurethane slab foam (hereinafter referred to as flexible slab foam).

[0050] In the manufacture of flexible mold foam, the mold temperature when injecting the foaming stock into the mold is usually 30 to 80°C, preferably 45 to 70°C. If the mold temperature when injecting the foaming stock into the mold is below 30°C, it may lead to a decrease in the reaction rate and an extension of the production cycle. On the other hand, if it is above 80°C, the reaction between water and isocyanate is excessively promoted compared to the reaction between polyol and isocyanate, which may cause the foam to collapse during the foaming process.

[0051] When the above foaming stock is allowed to harden, the hardening time is preferably 10 minutes or less, and more preferably 7 minutes or less, considering the production cycle of a typical flexible mold foam.

[0052] When manufacturing flexible molded foam, the above components can be mixed using a high-pressure foaming machine or a low-pressure foaming machine, as is the case with ordinary flexible molded foam.

[0053] It is preferable to mix the isocyanate component and the polyol component immediately before foaming. Other components can be pre-mixed with the isocyanate component or the polyol component 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 stored and used as needed. In the case of a foaming apparatus that can introduce more than two components simultaneously into the mixing section, polyols, foaming agents, isocyanates, catalysts, foam stabilizers, anti-foaming agents, etc., can also be introduced into the mixing section individually.

[0054] Furthermore, the mixing method may be either dynamic mixing, which is performed in the mixing chamber of the foaming machine's machine head, or static mixing, which is performed in the liquid delivery piping, or both may be used in combination. Static mixing is often used for mixing gaseous components such as physical foaming agents with liquid components, while dynamic mixing is often used for mixing components that can be stably stored as liquids. The foaming apparatus used in the present invention is preferably a high-pressure foaming apparatus that does not require solvent cleaning of the mixing section.

[0055] The mixture obtained by this mixing process is poured into a mold, allowed to foam and harden, and then demolded. To facilitate the demolding process, it is preferable to apply a release agent to the mold beforehand. Any release agent commonly used in the molding industry can be used.

[0056] Furthermore, in the manufacture of flexible molded foam, a film can be applied to the foam surface by integral molding to enhance the sound absorption effect at specific frequencies. The sound-absorbing film according to the present invention absorbs sound from the outside by converting relatively low-frequency sounds of 1000 to 2000 Hz into vibrational energy.

[0057] Integral mold forming is a method in which a film is placed in a shape along the inner surface on at least one of the lower mold or the upper mold of the mold in advance, and then a mixture is injected into the mold and demolded after foaming and curing. At least one film is arranged in the order of the film and the flexible polyurethane foam with respect to the sound source, but it may also be arranged on the opposite side of the sound source in order to increase the sound insulation rate.

[0058] For the film laminated on the flexible polyurethane foam, a non-ventilated 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, and polyamide resins such as 6-nylon, 6, 6-nylon, 11-nylon, and 12-nylon.

[0059] 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 molding processability during mold forming may deteriorate, and if it exceeds 250 μm, the sound absorption performance may decrease. Also, the density of the film is preferably 0.8 to 1.8 g / cm 3 is preferred. If the film density is less than 0.8 g / cm 3 there is a risk that a sufficient sound absorption effect cannot be obtained in the low frequency range, and if it exceeds the upper limit, the weight of the sound absorption material will become heavy.

[0060] As a method of forming a film layer on the surface of the flexible polyurethane foam, in-mold coating molding can also be performed in which an in-mold coating paint is applied in advance to at least one of the lower mold or the upper mold of the mold and then the polyurethane foam is molded.

[0061] In-mold coatings can be suitably used in both water-based and solvent-based forms, and may be either one-component or two-component curing types. Examples of resins for in-mold coatings include polyurethane resins, acrylic resins, polyester resins, and other known coatings. Among these, polyurethane resins are preferred, and moreover, aqueous polyurethane resin emulsions using a polyol component with a carbonate skeleton are preferred from the viewpoint of achieving a higher softening temperature. The polyol component with a carbonate skeleton may also contain ester groups other than the carbonate skeleton, and a mixture of an aqueous polyurethane resin emulsion using a polyol component with a carbonate skeleton and an aqueous polyurethane resin emulsion using a polyol component with ester groups may also be used. The average number of functional groups in the polyol component with a carbonate skeleton is preferably 2.1 or more. If the average number of functional groups is less than 2.1, the heat resistance of the resulting film layer is likely to be impaired.

[0062] Although the demolded product can be used as is, it is preferable to break the foam's cell membrane under compression or reduced pressure using a known method to stabilize the product's appearance and dimensions thereafter.

[0063] After demolding, the soft mold foam can be used after performing perforation treatments such as needle punching, thermal needle processing, or laser irradiation on the surface skin layer or laminated film portion to effectively direct sound wave energy into the internal porous layer and enhance the sound absorption effect on the high-frequency side. A perforation ratio of 0 to 2.0% is preferred. If the perforation ratio exceeds 2.0%, the sound absorption effect on the low-frequency side may decrease. Furthermore, when the perforation ratio exceeds 0%, the average perforation diameter is preferably 300 μm to 1000 μm, and more preferably 300 μm to 900 μm. If the average perforation diameter is less than 300 μm, there is a risk that the holes will be blocked by burrs generated during perforation, and if it exceeds 1000 μm, there is a risk that the sound absorption effect on the low-frequency side may decrease.

[0064] The manufacturing method for the flexible polyurethane foam described above produces a foam with a thickness of 5.0 to 50 mm and a density of 25 to 200 kg / m³. 3Furthermore, the C hardness of the foam test specimen is 5 to 85, the average sound absorption coefficient from 1000 Hz to 3500 Hz is 0.6 or higher, and the air permeability is 0.1 to 100 cm. 3 / cm 2 A flexible polyurethane foam can be obtained at a rate of / sec.

[0065] [Mechanism by which coarse cells provide high sound absorption] The flexible polyurethane foam according to the present invention achieves a high sound absorption effect by coarsening the cells with a defoaming agent. This is thought to be because the coarsening of the cells creates a Helmholtz resonator-type sound absorption mechanism within the flexible polyurethane foam, thereby increasing the sound absorption effect at specific frequencies. In a Helmholtz resonator, the air inside a container with an opening acts as a spring and resonates with vibrations at specific frequencies determined by the internal volume of the container and the area of ​​the opening. This resonance phenomenon causes the air introduced into the container to vibrate violently, and the noise energy is lost through friction, resulting in sound absorption.

[0066] In this invention, coarse cells are used as the container, while relatively small cells other than the coarse cells, pores present in the foam skin layer formed during manufacturing, or openings in the film are considered as the container opening. By adjusting the size of the coarse cells (internal volume of the container) so that the resonant frequency of the Helmholtz resonator is between 1000Hz and 3500Hz, it is believed that a high sound absorption effect can be achieved.

[0067] Furthermore, while flexible polyurethane foam is used in this invention, using rigid polyurethane foam may make it difficult to obtain a high sound absorption coefficient in the high-frequency range of 3000 Hz or higher. In addition, rigid polyurethane foam has characteristics such as difficulty in conforming to the shape when attached to vehicles, etc., and difficulty in restoring its shape after compression, which limits the applications in which it can be used. [Examples]

[0068] The present invention will be described more specifically below based on examples and comparative examples, but the present invention is not limited to the following examples. Unless otherwise specified, "parts" and "%" in this text refer to mass.

[0069] (Examples 1-10, Comparative Examples 1-2) [Preparation of polyol compositions] After purging a reactor equipped with a stirrer, condenser, nitrogen inlet tube, and thermometer with nitrogen, 40 g of polyol 1, 60 g of polyol 2, 2.5 g of crosslinking agent 1, 3.0 g of crosslinking agent 2, 0.4 g of catalyst 1, 0.06 g of catalyst 2, 1.0 g of foam stabilizer 1, 2.5 g of foam breaker 1, and 3.0 g of water were charged and stirred at 23°C for 0.5 hours to obtain polyol composition (P-1). As shown in Table 1, the other polyol compositions (P-2 to P-6) were prepared in the same manner as P-1.

[0070] [Preparation of isocyanate compositions] After purging a reactor equipped with a stirrer, condenser, nitrogen inlet tube, and thermometer with nitrogen, 100 g of isocyanate 1 and 2.8 g of antifoaming agent 1 were charged, and the mixture was stirred at 23°C for 0.5 hours to obtain isocyanate composition (I-2).

[0071] [Synthesis of polycarbonate polyols] In a 1L two-necked glass reactor equipped with a stirrer, thermometer, heater, and condenser, 31.3g of trimethylolpropane, 413.8g of 1,6-hexanediol, 454.9g of diethyl carbonate, and 0.045g of lithium acetylacetonate were mixed and reacted at atmospheric pressure at 100-150°C for 8 hours while removing low-boiling point components. The reaction temperature was then increased to 150°C, the pressure in the flask was reduced to 1kPa, and the reaction was continued for another 8 hours to obtain a polycarbonate polyol (PCP-1) with a number-average molecular weight of 1790g / mol and a hydroxyl value of 90.7mgKOH / g.

[0072] [Preparation of aqueous polyurethane resin emulsion] ·PUD-1 In a 1L reactor equipped with a stirrer, thermometer, nitrogen sealing tube, and condenser, 77.6g of N-980N (manufactured by Tosoh Corporation: number average molecular weight 2000; hydroxyl value 56.11 mg KOH / g; 1,6-hexanediol-based polycarbonate diol), 3.04g of 1,6-hexanediol, 26.9g of PCP-1, 75g of acetone, 5.29g of 2,2-dimethylolpropanoic acid, and 31.2g of isophorone diisocyanate were charged. The mixture was heated to 60°C and stirred at the same temperature for 30 minutes. Then, 0.12g of Neostan U-600 was added and the mixture was reacted for 5 hours. Next, 3.99g of triethylamine was added to neutralize the carboxyl groups, and then 320g of water was added while stirring to emulsify the mixture. After emulsification, 0.18 g of KL-245 was added, and within 30 minutes, amine water (containing 30 g of water and 1.99 g of isophorone diamine) was charged in, and the amine chain extension reaction was carried out at 40°C for 12 hours. Stirring was stopped when the presence of isocyanate groups could no longer be detected by FT-IR. Subsequently, the reaction solution was transferred to a 2 L round-bottom flask, and 75 g of acetone and 50 g of water were removed by vacuum distillation to obtain an aqueous polyurethane resin emulsion composition (PUD-1).

[0073] ·PUD-2 In a 1L reactor equipped with a stirrer, thermometer, nitrogen sealing tube, and condenser, 51.8g of N-980N (manufactured by Tosoh Corporation: number average molecular weight 2000; hydroxyl value 56.11 mg KOH / g; 1,6-hexanediol-based polycarbonate diol), 1.99g of 1,6-hexanediol, 53.8g of PCP-1, 75g of acetone, 5.29g of 2,2-dimethylolpropanoic acid, and 31.2g of isophorone diisocyanate were charged. The mixture was heated to 60°C and stirred at the same temperature for 30 minutes. Then, 0.12g of U-600 was added and the mixture was reacted for 5 hours. Next, 3.99g of triethylamine was added to neutralize the carboxyl groups, and then 320g of water was added while stirring to emulsify the mixture. After emulsification, 0.18 g of KL-245 was added, and within 30 minutes, amine water (containing 30 g of water and 1.99 g of isophorone diamine) was charged in, and the amine chain extension reaction was carried out at 40°C for 12 hours. Stirring was stopped when the presence of isocyanate groups could no longer be detected by FT-IR. Subsequently, the reaction solution was transferred to a 2 L round-bottom flask, and 75 g of acetone and 50 g of water were removed by vacuum distillation to obtain an aqueous polyurethane resin emulsion composition (PUD-2).

[0074] The raw materials used to obtain PUD-1 and PUD-2 are as follows. • Trimethylolpropane: Manufactured by Sigma-Aldrich • 1,6-Hexanediol: Manufactured by BASF-JAPAN • 2,2-Dimethylolpropionic acid: Manufactured by Tokyo Chemical Co., Ltd. • Isophorone diisocyanate: Manufactured by Evonik • Acetone: Manufactured by KH Neochem Co., Ltd. Triethylamine: Manufactured by Kishida Chemical Co., Ltd. Isophorone diamine: Manufactured by Tokyo Chemical Industry Co., Ltd. • NeoStan U-600: Manufactured by Nitto Kasei Co., Ltd. • KL-245: Manufactured by Evonik. ·Water: City water

[0075] Of the raw materials shown in Table 1, the liquid temperature of the isocyanate composition and the mixture of all raw materials other than the isocyanate composition (polyol composition) was adjusted to 24°C to 26°C. A predetermined amount of polyisocyanate component was added to the polyol composition, mixed in a mixer (7000 rpm) for 7 seconds, and then injected into a mold to foam flexible polyurethane foam. After that, it was removed from the mold and the physical properties of the obtained flexible polyurethane foam were measured.

[0076] [Foaming conditions] Mold temperature: 60-70℃ Mold shape: 200mm x 200mm x 10mm Mold material: Aluminum Cure time: 5 minutes Molded integral molding: Film is placed in the lower mold (Examples 2, 3, and 7) : In-mold coating paint was spray-applied to the lower mold (Examples 9 and 10).

[0077] [Table 1]

[0078] [Raw materials used] • Polyol 1: Polyoxyethylene polyoxypropylene polyol with an average number of functional groups = 3.0 and a hydroxyl value of 33 (mgKOH / g), manufactured by AGC Inc. (product name: Excenol 823) • Polyol 2: A polymer polyol with an average number of functional groups of 3.0 and a hydroxyl value of 24 (mgKOH / g), manufactured by AGC Inc. (product name: Exenol 923) Polyol 3: Unrefined castor oil with an average number of functional groups of 2.7 and a hydroxyl value of 160 (mgKOH / g), manufactured by Ito Oil Co., Ltd. (Product name: URIC H-24) • Polyol 4: Average number of functional groups = 4.0, hydroxyl value = 28 (mgKOH / g), polyoxyethylene polyoxypropylene polyol with 80% by mass of oxyethylene units in the polyether polyol, manufactured by Tosoh Corporation, NEF-024 (product name) • Crosslinking agent 1: Diethanolamine (manufactured by Mitsui Chemicals, Inc.) • Crosslinking agent 2: Triethanolamine (manufactured by Mitsui Chemicals, Inc.) • Catalyst 1: 33% dipropylene glycol solution of triethylenediamine (manufactured by Tosoh Corporation, product name: TEDA L-33) • Catalyst 2: 70% dipropylene glycol solution of bis(2-dimethylaminoethyl) ether (manufactured by Tosoh Corporation, product name: TOYOCAT ET) • Foam stabilizer 1: Silicone-based foam stabilizer (manufactured by Momentive, product name: L-5309J) • Foam stabilizer 2: Silicone-based foam stabilizer (manufactured by Dow-Toray, product name: SRX-280A) • Anti-foaming agent 1: GC-302SS (product name), silicone-based anti-foaming agent manufactured by Nisshin Chemical Research Institute Co., Ltd. • Isocyanate 1: Polyphenylene polymethylene polyisocyanate with an MDI content of 70% by mass and an isomer content of 17.7% by mass (manufactured by Tosoh Corporation, product name: CEF-507) • Film: Thermoplastic polyurethane elastomer film with a film thickness of 30 μm (manufactured by Okura Industries Co., Ltd., product name: Silklon ET85) • PUD-1, PUD-2: In-mold coating paints

[0079] [Moldability evaluation] In Table 1, a "○" rating for moldability means that the flexible polyurethane foam could be molded without collapse (significant sinking after reaching its highest height) or shrinkage of the generated polyurethane foam immediately after foaming or curing. A "×" rating means that collapse, shrinkage, or other phenomena occurred in the polyurethane foam.

[0080] [Apparent Density] It was determined by the method described in JIS K6400.

[0081] [C hardness] The measurement was performed using a rubber hardness tester (Asuka-C type) as specified in JIS K7312.

[0082] [Air permeability] The measurements were taken using the method described in JIS K6400.

[0083] [Sound absorption coefficient] Based on the method described in JIS A1405-2:2007, the normal incidence sound absorption coefficient was measured at 500-6400 Hz using a Bruel Kjær Japan Model 4206 acoustic tube. The sound absorption coefficient was measured using a 28.8 mm diameter, 10 mm thick urethane foam, positioned with the lower mold surface facing the sound source, and without an air layer behind the urethane foam.

[0084] [Average cell diameter] The average cell diameter of each polyurethane foam molded product was determined by cutting a 10mm thick molded product into a disc shape with a diameter of 28.8mm, and using a microscope equipped with a Moritex MTL5518C-034-01 lens to capture an image of the foam's side surface with a field of view of 10mm vertically and 16.3mm horizontally. The cell diameter of a predetermined number of cells present in the field of view was measured, and the average of these cell diameters was calculated.

[0085] [Area percentage occupied by cells with a diameter of 5000 μm or more] The area percentage occupied by cells with a diameter of 5000 μm or more in each polyurethane foam molded body was calculated by cutting a 10 mm thick molded body into a disc shape with a diameter of 28.8 mm, and using a microscope equipped with a Moritex lens MTL5518C-034-01 to capture an image of the foam cross-section with a field of view of 10 mm vertically and 16.3 mm horizontally. The area of ​​cells with a diameter of 5000 μm or more present in the field of view was measured, and the area was calculated based on the following formula. Area ratio occupied by cells with a diameter of 5000 μm or more = (Total area of ​​cells with a diameter of 5000 μm or more / Field of view) × 100 ... (Formula)

[0086] As shown in Comparative Example 1 of Table 1, when no foam-breaking agent is used, the average sound absorption coefficient in the 1000-3500 Hz range is extremely low. In this case, the average cell diameter is smaller compared to the example. As shown in Comparative Example 2, even when a foam-breaking agent is used, if the amount used is too much compared to the specified amount, the molding stability of the foam is significantly reduced, and the foam cannot be molded.

[0087] By comparing the above examples and comparative examples, it is clear that the present invention yields a molded article with a thin base material thickness and high sound absorption performance across a wide frequency range when used as a sound-absorbing material, demonstrating the significance and remarkable excellence of the present invention's configuration.

Claims

1. A flexible polyurethane foam molding composition comprising a polyol component (A) and a polyisocyanate component (B), wherein the polyol component (A) includes a catalyst (C), a foam stabilizer (D), and a blowing agent (E), and at least one of the polyol component (A) or the polyisocyanate component (B) contains a foam defoaming agent (F), and the content of the foam defoaming agent is 0.1 to 7.5% by mass of the total amount of the flexible polyurethane foam molding composition. A composition for molding flexible polyurethane foam, characterized in that the polyisocyanate component (B) contains diphenylmethane diisocyanate in an amount of 50 to 85% by mass, and the total amount of 2,2'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate contained in the diphenylmethane diisocyanate is 10 to 50% by mass relative to the total amount of diphenylmethane diisocyanate.

2. The flexible polyurethane foam molding composition according to claim 1, characterized in that the antifoaming agent (F) is a silicone-based oil and the number-average molecular weight of the polysiloxane component contained in the silicone-based oil is 10,000 to 50,000.

3. The flexible polyurethane foam molding composition according to claim 1 or 2, characterized in that the antifoaming agent (F) is included in the polyol component (A).

4. A flexible polyurethane foam obtained by reacting and foaming a flexible polyurethane foam molding composition according to any one of claims 1 to 3.

5. The flexible polyurethane foam according to claim 4, characterized in that, in a sound absorption coefficient measurement method compliant with JIS A1405-2:2007, the simple average value of the sound absorption coefficient in the frequency range of 1000 Hz to 3500 Hz is 0.6 or more.

6. Density of 25-200 kg / m³ ３ Furthermore, the C hardness of the foam test specimen is 5.0 to 85, and the air permeability is 0.1 to 100 cm. ３ / cm ２ The flexible polyurethane foam according to claim 4 or 5, characterized in that it is / sec.

7. The flexible polyurethane foam according to any one of claims 4 to 6, characterized in that the average cell diameter of the flexible polyurethane foam is 2000 μm or more, and the area ratio occupied by cells with a diameter of 5000 μm or more is 20% or more.

8. A flexible polyurethane foam according to any one of claims 4 to 7, characterized in that the thickness of the thinnest part is 5.0 to 50 mm.

9. A foamed laminate comprising a flexible polyurethane foam and a film according to any one of claims 4 to 8, characterized in that at least one film is arranged in the order of film, then the flexible polyurethane foam, relative to a sound source.

10. A foamed laminate comprising a flexible polyurethane foam and a film, wherein a flexible polyurethane foam molding composition comprising a polyol component (A) and a polyisocyanate component (B) is reacted and foamed, At least one film is arranged relative to the sound source in the order of film, then the soft polyurethane foam. A foamed laminate characterized in that the polyol component (A) comprises a catalyst (C), a foam stabilizer (D), and a blowing agent (E), and at least one of the polyol component (A) or the polyisocyanate component (B) contains a foam-de-foaming agent (F), wherein the content of the foam-de-foaming agent is 0.1 to 7.5% by mass relative to the total amount of the flexible polyurethane foam molding composition.

11. The foamed laminate according to claim 10, characterized in that the defoaming agent (F) is a silicone oil and the number average molecular weight of the polysiloxane component contained in the silicone oil is 10,000 to 50,000.

12. The foamed laminate according to claim 10 or 11, characterized in that the antifoaming agent (F) is included in the polyol component (A).

13. The foamed laminate according to any one of claims 9 to 12, wherein the film is coated on the foam surface by integral molding with the flexible polyurethane foam.

14. The foamed laminate according to any one of claims 9 to 13, characterized in that the film is a polyurethane resin film.

15. The foamed laminate according to claim 14, characterized in that the polyurethane resin film is obtained from an aqueous polyurethane resin emulsion.

16. The foamed laminate according to claim 15, characterized in that the polyol component used in the aqueous polyurethane resin emulsion has a carbonate skeleton.

17. The foamed laminate according to claim 16, characterized in that the average number of functional groups of the polyol component having the carbonate skeleton is 2.1 or more.

18. The foamed laminate according to any one of claims 9 to 17, characterized in that the thickness of the film is 0.1 to 250 μm, the porosity is 0 to 2.0%, and the average porosity when the porosity exceeds 0% is 300 μm to 1000 μm.

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