JP2005193612A - Rigid polyurethane foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rigid polyurethane foam which has buckling properties, is excellent in sound insulating/absorbing performance, and can be used suitably as a sound insulating/absorbing material. <P>SOLUTION: The rigid polyurethane foam is composed of three layers of a high density surface layer (X1) having holes penetrating the layer, a low density inside layer (Y1), and a high density surface layer (X2). The thickness of each of the layers (X1) and (X2) is at least 0.5 mm. The average maximum diameter of the holes is 0.01-100 mm. The total area of the holes in the surface of the layer (X1) is preferably 1-80% of the surface area of the layer (X1). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to rigid polyurethane foam. More specifically, the present invention relates to a rigid polyurethane foam suitable for a sound absorbing material for vehicles such as automobiles.

Conventionally, the sound-absorbing and sound-absorbing material is, for example, disposed around the driver's seat of an automobile in order to block sound from the engine unit, and a thermosetting flexible polyurethane foam has been used. For example, Patent Document 1 is known as a flexible polyurethane foam excellent in sound insulation performance.
Japanese Patent Laid-Open No. 5-84858

  However, the flexible polyurethane foam does not have a buckling performance, and when the automobile has an accident, there is a drawback that a high stress is applied to an impacted object and the driver is damaged on the foot. In addition, the conventional rigid polyurethane foam has a buckling performance but does not have a sound absorption performance, and thus cannot be used as a sound absorbing material.

The present inventors have intensively studied to solve these problems, and have reached the following invention.
That is, the present invention includes the following (I) and (II).
(I) A rigid polyurethane foam comprising three layers of a surface high-density layer (X1), an internal low-density layer (Y1), and a surface high-density layer (X2), wherein (X1) has pores penetrating the layer.
(II) A sound absorbing material made of the above rigid polyurethane foam.

  The rigid polyurethane foam of the present invention has a buckling performance and an excellent sound absorbing performance. Therefore, it is useful as a high performance sound absorbing material for automobiles.

The rigid polyurethane foam of the present invention has a surface high-density layer (X1), a low-density internal layer (Y1), and a high-density surface layer having holes penetrating from the surface to the internal low-density layer (Y1) in the thickness direction. X2). When used as a sound-absorbing material, normally (X1) is used with the incident sound side and (X3) on the opposite side, but if (X1) does not have a through-hole, it will be incident. Sound is blocked by the surface high-density layer and sufficient sound-absorbing performance cannot be obtained. Further, if the foam is not a three-layer foam having a high density layer on the surface, it will not have high buckling performance.
The rigid polyurethane foam of the present invention preferably has a molecular weight between crosslinking points of 400 to 1,000.

As for the size of the hole of (X1), the average of the maximum diameter (diameter when the cross section is a circle) is preferably 0.01 to 100 mm. The lower limit is more preferably 0.1 mm, particularly preferably 0.3 mm, and the upper limit is further preferably 40 mm, particularly preferably 10 mm, and most preferably 3 mm. When the average maximum diameter of the holes is 0.01 to 100 mm, the sound-absorbing performance suitable as a vehicle member is obtained.
The shape of the cross section of the hole is not particularly limited, but is preferably a circle or a shape close to a circle (indeterminate shape or polygon), and more preferably a circle.

Moreover, the total area of the pores on the surface of the surface high-density layer (X1) is preferably 1 to 80% with respect to the surface area of (X1) [surface area of the surface where only (X1) excluding the side surface portion appears). . The lower limit is more preferably 2%, particularly preferably 3%, and the upper limit is more preferably 30%, particularly preferably 10%, most preferably 8%. When the total area of the holes is 1 to 80%, the sound absorbing performance suitable as a vehicle member is obtained.
In the present invention, the average maximum diameter of the holes and the ratio of the total area of the holes to the surface area of (X1) are measured by the following method.
The surface of (X1) of the foam is photographed at 10 random locations, and the sample is enlarged to an appropriate size (for example, 2 to 100 times, preferably 5 to 10 times) as necessary. The average maximum diameter is obtained by arithmetically averaging the maximum diameter of the holes in the photograph. Moreover, the total of the area of a hole is measured and the ratio with respect to the total surface area of (X1) of the measured range is calculated. In addition, when the cross section of a hole is circular and a diameter is known beforehand, you may obtain | require by calculation from the area of one hole, and the number of the holes opened.

The thicknesses of (X1) and (X2) are each preferably 0.5 mm or more. The lower limit of the thickness is more preferably 0.8 mm, particularly preferably 1 mm, and the upper limit is more preferably 10 mm. When the thickness of the high-density layer is 0.5 mm or more, when stress is applied to the foam, the cell is uniformly stressed, and random impact of the cell does not occur, and sufficient shock absorbing ability is obtained.
The thickness of the internal low density layer (Y1) is preferably 100 mm or less, more preferably the lower limit is 1 mm and the upper limit is 90 mm. The thickness of the entire foam is preferably 2 to 120 mm, more preferably the lower limit is 5 mm and the upper limit is 100 mm.

The size of the rigid polyurethane foam of the present invention varies depending on the application to be used and is not particularly limited. For example, when used as a sound absorbing material for undercarriage of a driver's seat of an automobile, the surface area of (X1) or (X2) 5,000 to 30,000 cm ² is preferable.

The portion of the surface high-density layer (X1) having holes penetrating the layer excluding the holes and the density of the surface high-density layer (X2) are preferably 100 to 300 kg / m ³ , and the density of the internal low-density layer (Y1) Is preferably 10 to 70 kg / m ³ . The density of the portion excluding the holes of (X1) is the density of (X1 ′) before the holes are formed when (X1) is obtained by forming holes in the high-density layer (X1 ′). Equivalent to.
The lower limit of the density of (X1) excluding the holes and (X2) is more preferably 110 kg / m ³ , particularly preferably 120 kg / m ³ , and the upper limit is more preferably 200 kg / m ³ , especially Preferably it is 180 kg / m ³ . The lower limit of the density of (Y1) is more preferably 15 kg / m ³ , particularly preferably 20 kg / m ³ , and the upper limit is further preferably 50 kg / m ³ , particularly preferably 40 kg / m ³ . When the portion excluding the hole of (X1) and the density of (X2) is 100 to 300 kg / m ³ , both strength and light weight can be achieved as a vehicle member, and the density of (Y1) is 10 to 70 kg / m. ^If it is ³ , it has a suitable shock absorbing ability.
The thickness and density of each layer can be adjusted to the said range by adjusting the quantity of the foaming agent and catalyst which are mentioned later, for example.

In the rigid polyurethane foam of the present invention, three layers of a surface high-density layer (X1) having a hole penetrating the layer, an internal low-density layer (Y1), and a surface high-density layer (X2) are prepared separately. However, since the process is not complicated, a single foam-forming composition containing a water-based foaming agent is poured into the mold in one step. A hole is made in the layer (X1 ′) of the rigid polyurethane foam formed of the three layers of the surface high-density layer (X1 ′), the internal low-density layer (Y1), and the surface high-density layer (X2) ( X1) is preferred. If the single foam-forming composition is formed by pouring into a mold in a single step, it can correspond to the complicated shape of the vehicle member.
Such a three-layered rigid polyurethane foam formed in one step can be obtained, for example, by selecting the composition of the polyol component as described later.

  The means for making holes in the rigid polyurethane foam is not particularly limited, but it is preferable to post-process by a physical method rather than using chemicals to make holes. Examples of the physical post-processing include a method of using a needle, a thousand sheets, a drill, a nail, a cork borer, etc., manually or by using a movable device to which a plurality of these are attached, a method of punching with compressed air, and the like. Among these, a method using a needle is preferable, and it is more preferable to use a jig in which a plurality of (for example, 10 to 200) needles having the same size are arranged like Kenzan. By using a sword-shaped jig, it is possible to obtain a surface high-density layer (X1) with holes that are evenly spaced, and to uniformly incorporate sound into the internal low-density layer (Y1). , Can have good sound absorption.

The rigid polyurethane foam of the present invention preferably has a sound absorption coefficient of 45% or more in the entire region having a frequency of 1500 Hz to 4000 Hz. More preferably, it is 60% or more, and particularly preferably 70% or more. When the sound absorption coefficient is 45% or more in the entire region, sound absorption performance suitable as a vehicle member is obtained.
Moreover, it is preferable that the foam of this invention is 15% or more in the whole area | region where a sound absorption coefficient is 800 Hz or more and less than 1500 Hz. More preferably, it is 25% or more, and particularly preferably 30% or more. When the sound absorption coefficient is 15% or more in the entire region, sound absorption performance suitable as a vehicle member is obtained.
The method for measuring the sound absorption rate is as follows.
The sample is in a state where the surface high-density layer (X1) / inner low-density layer (Y1) / surface high-density layer (X2) are stacked in the height direction, cut into a cylindrical shape with a diameter of 3 cm, and (X1) is incident As the sound side, the sound absorption coefficient with respect to the frequency is measured by a normal incidence sound absorption coefficient measuring apparatus (2-microphone method) manufactured by Rion Co., Ltd.

The rigid polyurethane foam of the present invention has a longitudinal direction [surface high-density layer (X1) / internal low-density layer (Y1) / surface high-density layer (X2) in a stress compression strain curve when laminated vertically. It is preferable that the compressibility in the vertical direction is in the range of 10 to 60% with respect to the thickness of the foam and the compressive stress is 550 ± 300 N because the buckling performance is good. The stress range is preferably 550 ± 280N, more preferably 550 ± 250N.
The method for measuring the compressive stress is as follows.
A sample is cut into 50 mm x 50 mm, and the stress with respect to a compression rate of 0 to 90% is measured with an autograph "AG-I20kN" manufactured by Shimadzu Corporation.

If the rigid polyurethane foam of the present invention has the above-described surface high-density layer (X1) having pores penetrating the layer, internal low-density layer (Y1), and surface high-density layer (X2), the composition The above is not particularly limited.
Specifically, for example, a polyol component composed of a polymer polyol (A) and / or a polyol (B) obtained by polymerizing a vinyl monomer (b) in a polyol (a), a polyisocyanate component (C), and water. It can be obtained by reacting a polyol component and (C) using a foam-forming composition comprising a foaming agent (D) as a main component, a catalyst (E), and, if necessary, a foam stabilizer (F).

The above polyols (a) and (B) are compounds containing at least 2 (preferably 2 to 8) hydroxyl groups [however, one hydroxyl group and 1 to 7 or more other activities. A small amount (preferably 10% or less) of a compound having a hydrogen-containing group (amino group, imino group, mercapto group, etc.) may be contained. ], For example, an active hydrogen-containing compound having 2 to 8 or more valences such as polyhydric alcohol, polyhydric phenol, amine, polycarboxylic acid, phosphoric acid, etc. A compound having a structure to which AO) is added [(poly) ether polyol] may be mentioned, and two or more of them may be used in combination.
In the above and below, “%” means “% by mass” unless otherwise specified.

  Examples of the polyhydric alcohol include dihydric alcohols having 2 to 20 carbon atoms (aliphatic diols such as ethylene glycol, propylene glycol, 1,3- and 1,4-butanediol, 1,6-hexanediol, neopentyl Alkylene glycols such as glycols; and alicyclic diols such as cycloalkylene glycols such as cyclohexanediol and cyclohexanedimethanol, trihydric alcohols having 3 to 20 carbon atoms (aliphatic triols such as glycerin, trimethylolpropane, Alkanetriols such as methylolethane and hexanetriol); 4 to 8 or more polyhydric alcohols having 5 to 20 carbon atoms (aliphatic polyols such as pentaerythritol, sorbitol, mannitol, sorbitan, jigs) Alkane polyols such as serine and dipentaerythritol and intramolecular or intermolecular dehydrates of alkanetriols; and sugars such as sucrose, glucose, mannose, fructose, and methylglucoside and their derivatives), and two or more of these The combined use etc. are mentioned.

  Examples of the polyhydric phenol include monocyclic polyphenols such as pyrogallol, hydroquinone, and phloroglucin; bisphenols such as bisphenol A, bisphenol F, and bisphenolsulfone; Examples thereof include polyphenols described in US Pat. No. 3,265,641; and combinations of two or more thereof.

Examples of the amine include ammonia; an aliphatic amine, an alkanolamine having 2 to 20 carbon atoms (for example, monoethanolamine, diethanolamine, triethanolamine, and isopropanolamine), and an alkylamine having 1 to 20 carbon atoms (for example, n- Butylamine and octylamine), alkylene diamines having 2 to 6 carbon atoms (for example, ethylene diamine, propylene diamine and hexamethylene diamine), polyalkylene polyamines having 4 to 20 carbon atoms (dialkylene triamine having 2 to 6 carbon atoms in the alkylene group) -Hexaalkyleneheptamine, such as diethylenetriamine and triethylenetetramine).
C6-C20 aromatic mono- or polyamines (for example, aniline, phenylenediamine, tolylenediamine, xylylenediamine, diethyltoluenediamine, methylenedianiline, and diphenyletherdiamine); C4-C20 alicyclic Amines (for example, isophorone diamine, cyclohexylene diamine, and dicyclohexyl methane diamine); heterocyclic amines having 4 to 20 carbon atoms (for example, those described in piperazine, aminoethylpiperazine, and Japanese Patent Publication No. 55-21044), and these 2 The combined use of more than seeds is mentioned.

Examples of the polycarboxylic acid include aliphatic polycarboxylic acids having 4 to 18 carbon atoms such as succinic acid and adipic acid; aromatic polycarboxylic acids having 8 to 18 carbon atoms such as phthalic acid, terephthalic acid and trimellitic acid. .
Two or more of these active hydrogen compounds may be used in combination. Of these, polyhydric alcohols are preferred.

  The AO having 2 to 8 or more carbon atoms includes ethylene oxide (hereinafter referred to as EO), propylene oxide (hereinafter referred to as PO), 1,2-, 1,3-, 1,4- and 2,3-butylene. Examples thereof include oxides, styrene oxides, and combinations of two or more of these (block and / or random addition).

  Moreover, you may use 1 or more types of polyols other than the above in a polyol component. Examples of the other polyol include polyester polyol (reaction product of the polyhydric alcohol and the polycarboxylic acid), the polyhydric alcohol, and the alkanolamine.

  The hydroxyl value of the above polyols (a) and (B) as a whole [component obtained by removing the polymer (b) from the polyol component] is preferably 100 to 1000 (mg KOH / g, the same applies to the following hydroxyl values). The lower limit is preferably 140 and the upper limit is preferably 800.

Among the polyol components, the polyol (B) preferably contains one or more alkanolamines (a1). When (a1) is contained, a foam having a three-layer structure of (X1 ′) / (Y1) / (X2) can be easily obtained.
(A1) preferably has 2 to 9 carbon atoms, more preferably 2 to 6 carbon atoms. Specific examples include one or more selected from monoethanolamine, diethanolamine, and triethanolamine, with diethanolamine being preferred.

More preferably, the polyols (a) and / or (B) also contain the following (a2) and (a3).
(A2): Polyoxypropylene polyol having an average functional group number of 2 to 7 and a hydroxyl value of 200 to 600.
(A3): The average number of functional groups is 2 to 5, the hydroxyl value is 20 to 80, and the content of oxyethylene units (hereinafter referred to as EO units) is 0 to 70% (polyoxyethylene). Polyoxypropylene polyol.

Examples of the polyol (a2) include PO adducts of one or more active hydrogen-containing compounds, and two or more of them may be used in combination.
The average number of functional groups per molecule of (a2) is 2-7. The lower limit is preferably 2.5, more preferably 3, and the upper limit is preferably 6, more preferably 5.5. Even if the number of functional groups outside this range is included, the average functional group number may be 2 to 7 using an AO adduct of two or more active hydrogen-containing compounds (the following average functional group number) The same). Here, the average functional group number is a theoretical value calculated from the average functional group number of the active hydrogen-containing compound as a raw material, and is regarded as the functional group number.
The hydroxyl value of (a2) is 200-600. The lower limit is preferably 250, more preferably 300, and the upper limit is preferably 550, more preferably 500.
When the average number of functional groups in (a2) is 2 or more, the compression set rate is improved, and when it is 7 or less, the elongation property is improved. When the hydroxyl value is 200 or more, the hardness of the foam is improved, and when it is 600 or less, the elongation property is improved.

Examples of the polyol (a3) include AO adducts of one or more active hydrogen-containing compounds, and two or more of them may be used in combination. The AO is PO alone or a combination of EO and PO. When EO and PO are used in combination, any of block addition, random addition, or a combination thereof may be used.
The average number of functional groups per molecule of (a3) is 2-5. The lower limit is preferably 2.2, more preferably 2.5, and the upper limit is preferably 4.5, more preferably 4. The hydroxyl value is 20-80. The lower limit is preferably 30, more preferably 40, and the upper limit is preferably 70, more preferably 65. The content of EO units is 70% or less. Preferably it is 1-69%, More preferably, it is 2-68%.
When the average number of functional groups in (a3) is 2 or more, the compression set rate is improved, and when it is 5 or less, the elongation property is improved. When the hydroxyl value is 20 or more, the hardness of the foam is improved, and when it is 80 or less, the elongation property is improved. When the content of EO units is 70% or less, a continuous foam is obtained, and a foam with good moldability is obtained.

The polymer polyol (A) in the present invention can be produced by polymerizing the vinyl monomer (b) in the polyol (a) by an ordinary method.
For example, in at least one polyol selected from the above (a2) and (a3), the vinyl monomer (b) is polymerized in the presence of a radical polymerization initiator to obtain a polyol in which the polymer is stably dispersed. Things. In view of good dispersion stability, a polymer obtained by polymerizing (b) in (a3) is preferred.
Specific examples of the polymerization method include those described in US Pat. No. 3,383,351, Japanese Examined Patent Publication No. 39-25737, and the like.

  As the radical polymerization initiator, those which generate free radicals and initiate polymerization can be used, for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvalero). Nitrile), 2,2′-azobis (2-methylbutyronitrile) and the like; organic peroxides such as dibenzoyl peroxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide and persuccinic acid; And inorganic peroxides such as persulfate and perborate. In addition, these can use 2 or more types together.

As (b), aromatic vinyl monomer (b1), unsaturated nitrile (b2), (meth) acrylic acid ester (b3), other vinyl monomers (b4), and two or more of these A mixture is mentioned.
Examples of (b1) include styrene, α-methylstyrene, hydroxystyrene, chlorostyrene, and the like.
Examples of (b2) include acrylonitrile and methacrylonitrile.
Examples of (b3) include those composed only of C, H, and O atoms, and include methyl (meth) acrylate, butyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, and dodecyl (meta). ) Acrylate, eicosyl (meth) acrylate, docosyl (meth) acrylate and other (meth) acrylate alkyl (1-30 carbon atoms) ester; hydroxypolyalkylene mono (meth) acrylate (for example, alkylene group having 2 to 4 carbon atoms, And the number average molecular weight of the polyoxyalkylene chain is 200 to 1000).
Other vinyl monomers (b4) include vinyl group-containing carboxylic acids and their derivatives [(meth) acrylic acid, (meth) acrylamide, etc.], aliphatic or alicyclic hydrocarbon monomers [ethylene, propylene, Norbornene, etc.], fluorine-containing vinyl monomers (perfluorooctylethyl methacrylate, perfluorooctylethyl acrylate, etc.), nitrogen-containing vinyl monomers other than the above (diaminoethyl methacrylate, morpholinoethyl methacrylate, etc.), vinyl-modified silicone, etc. Is mentioned.
Among these, (b1) and (b2) are preferable, and styrene and / or acrylonitrile are more preferable.

Although the mass ratio of these (b) is not specifically limited, As an example, it is as follows.
(B1) and / or (b2) is preferably 5 to 100%, more preferably 10 to 100%. The mass ratio of (b1) and (b2) is not particularly limited, but is preferably 0/100 to 80/20. (B3) is preferably 0 to 50%, more preferably 0 to 20%. (B4) is preferably 0 to 10%, more preferably 0 to 5%.
By using a small amount (preferably 0.05 to 1%) of a polyfunctional (preferably 2 to 8 functional) vinyl group-containing monomer [divinylbenzene, ethylene di (meth) acrylate, etc.] in (b), The strength of the coalescence can be further improved.
The content of the polymer (b) in (A) is preferably 3 to 50%, more preferably 5 to 45%.

In the present invention, when the polyol component contains (a1), (a2), and (a3), each content based on the total mass of (a) and (B) is such that (a1) is 1 to 1 It is preferable that 10%, (a2) is 25 to 89%, and (a3) is 10 to 70%. The lower limit of (a1) is more preferably 2%, particularly preferably 3%, and the upper limit is more preferably 9%, particularly preferably 8%. The lower limit of (a2) is more preferably 30%, particularly preferably 35%, and the upper limit is more preferably 80%, particularly preferably 75%. The lower limit of (a3) is more preferably 15%, particularly preferably 20%, and the upper limit is more preferably 65%, particularly preferably 60%. Other polyols other than these are preferably 5% or less, more preferably 1% or less.
When (a1) is 1% or more, the compression set shows a good value, and when it is 10% or less, the elongation property shows a good value. When (a2) is 25% or more, the foam hardness shows a good value, and when it is 89% or less, the elongation property shows a good value. When (a3) is 10% or more, the curing property is improved, and when it is 70% or less, the foam hardness is improved.

  In the present invention, the polyol component preferably contains the polymer polyol (A). Further, the content of the polymer in the polyol component is preferably 5 to 25% or less. The lower limit is more preferably 7%, particularly preferably 10%, and the upper limit is more preferably 23%, particularly preferably 20%. If it is 5% or more, the stretched physical properties of the foam are good, and if it is 25% or less, a foam having an appropriate hardness can be obtained.

As the polyisocyanate component (C) in the present invention, those generally used for polyurethane are used.
For example, an aromatic polyisocyanate having 6 to 20 carbon atoms (excluding the carbon number in the NCO group) and a crude product thereof [2,4- or 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4 ′ -Or 4,4'-diphenylmethane diisocyanate (MDI), crude MDI (polymethylene polyphenylene polyisocyanate), polyaryl polyisocyanate (PAPI), etc.]; aliphatic polyisocyanate having 2 to 18 carbon atoms [hexamethylene diisocyanate, lysine isocyanate] C4-15 alicyclic polyisocyanate [isophorone diisocyanate, dicyclohexyl diisocyanate, etc.]; C8-15 araliphatic polyisocyanate [xylylene diisocyanate, etc.]; modified products of these polyisocyanates Urethane group, carbodiimide group, allophanate group, urea group, biuret group, uretdione group, uretonimine groups, isocyanurate groups or oxazolidone group-containing modified compounds, etc.] and use of two or more types of these can be cited.
Of these, preferred are TDI, MDI, crude MDI, PAPI, carbodiimide group-containing modified MDI, and combinations of two or more thereof. More preferred are MDI, crude MDI, PAPI, carbodiimide group-containing modified MDI, and combinations of two or more thereof.
The NCO group content of (C) is preferably 20 to 35%.

The foaming agent (D) in the present invention uses a foaming agent mainly composed of water.
It is preferable to use only water as (D), but other foaming agents may be used in combination within a range of 50% or less (more preferably 10% or less, particularly preferably 1% or less) in (D). .
As other foaming agents, those usually used for polyurethane are used, and as examples, hydrofluorocarbons such as HFC-134a, HFC-152a, HFC-356mff, HFC-236ea, HFC-245ca, HFC-245fa, HFC- 365 mfc, HFC-227ea and the like, and examples of the low boiling point compound include butane, pentane, cyclopentane and the like.
The amount of (D) used is preferably 3 to 8 parts with respect to 100 parts by mass of the polyol component (hereinafter, “parts by mass” is simply abbreviated as “parts”). The lower limit is more preferably 4 parts, and the upper limit is more preferably 7 parts.

As the catalyst (E) in the present invention, all usual catalysts for promoting the urethanization reaction can be used. Examples include triethylenediamine, bis (N, N-dimethylamino-2-ethyl) ether, N, N. Tertiary amines such as N, N ′, N′-tetramethylhexamethylenediamine and carboxylates thereof; organometallic compounds such as metal carboxylates such as potassium acetate, potassium octylate, stannous octoate, dibutyltin dilaurate; Is mentioned.
The amount of (E) used is preferably 0.05 to 10 parts, more preferably 0.1 to 8 parts, relative to 100 parts of the polyol component.

As the foam stabilizer (F) in the present invention, all those used in the production of ordinary polyurethane foams can be used. For example, a dimethylsiloxane foam stabilizer [for example, “SRX manufactured by Toledo Corning Silicone Co., Ltd.” -253 ", etc.], polyether-modified dimethylsiloxane foam stabilizers (for example," L-5309 "," SZ-1311 "manufactured by Nippon Unicar Co., Ltd.," SF-2972 "manufactured by Toray Dow Corning Silicone Co., Ltd.) ”,“ SF-2965 ”,“ SH-193 ”,“ SRX-274C ”, etc.].
The amount of (F) to be used is preferably 4 parts or less, more preferably 0.2 to 3 parts, and particularly preferably 0.5 to 2 parts with respect to 100 parts of the polyol component.

In the present invention, if necessary, other auxiliary components as described below may be used and reacted in the presence thereof.
For example, colorants (dyes, pigments), flame retardants (phosphate esters, halogenated phosphate esters, etc.), anti-aging agents (triazoles, benzophenones, etc.), antioxidants (hindered phenols, hindered amines) Etc.) and the like.
With respect to the amount of these auxiliary components used relative to 100 parts of the polyol component, the colorant is preferably 1 part or less. The flame retardant is preferably 5 parts or less, more preferably 2 parts or less. The anti-aging agent is preferably 1 part or less, more preferably 0.5 part or less. The antioxidant is preferably 1 part or less, more preferably 0.01 to 0.5 part.

  In the present invention, the isocyanate index (INDEX) [(NCO group / active hydrogen atom-containing group) equivalent ratio × 100] in the production of polyurethane foam is preferably 65 to 130, more preferably 70 to 120, and particularly preferably. 90-110. When the isocyanate index is 65 or more, the compression set of the foam is good, and when it is 130 or less, the curing time of the foam can be shortened.

  An example of the method for producing the rigid polyurethane foam of the present invention (before the layer (X1 ') is perforated) is as follows. First, a predetermined amount of a polyol component, a foaming agent (D), a catalyst (E), and, if necessary, a foam stabilizer (F) and other auxiliary components are mixed. Subsequently, this mixture and polyisocyanate component (C) (each liquid temperature: 15-70 degreeC) are rapidly mixed using a polyurethane low pressure or high pressure injection foaming machine, or a stirrer. The obtained mixed solution (foaming stock solution) is poured into a sealed mold (made of metal or resin, mold temperature is 5 to 100 ° C.) with a skin material set as necessary, and a urethanization reaction is performed for a predetermined time ( 5 to 1800 seconds) After curing, demold to obtain polyurethane foam. As for the pack rate at the time of pouring into a closed mold, 100 to 200% is preferable.

  Examples of the skin material set in the mold before foaming include ethylene propylene diene monomer polymer (EPDM), polyolefin (olefin having 2 to 8 carbon atoms, for example, polyethylene, polypropylene), and polyvinyl chloride. The thickness of the skin material is preferably 0.5 to 10 mm, more preferably 1 to 5 mm.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited by this.

The polyurethane foam raw materials in Examples and Comparative Examples are as follows.
(1) Polyol a1-1: Diethanolamine (2) Polyol a2-1: A polyol having a hydroxyl value of 400 obtained by adding PO to pentaerythritol.
(3) Polyol a2-2: A polyol having a hydroxyl value of 450 obtained by adding PO to a mixture of sucrose and glycerin (average number of functional groups: 5).
(4) Polyol a3-1: A polyol having a hydroxyl value of 56 obtained by adding PO to glycerin and then adding EO as a block. EO unit content 20%.
(5) Polyol a3-2: A polyol having a hydroxyl value of 50 obtained by adding EO to glycerin and then randomly adding PO and EO (mass ratio 7/3). EO unit content 68%.
(6) Polyol a3-3: A polyol having a hydroxyl value of 36 obtained by adding PO to glycerin and then adding EO in blocks. EO unit content 16%.
(7) Polymer polyol A-1: Acrylonitrile and styrene (mass ratio) in a polyol (a3-4) having a hydroxyl value of 56 and an EO unit content of 5% obtained by block addition of glycerin in the order of PO / EO / PO 2: 8) polymer polyol obtained by polymerizing (polymer content 42%).
(8) Polymer polyol A-2: obtained by polymerizing acrylonitrile in a polyol (a3-5) having a hydroxyl value of 34 and an EO unit content of 14% obtained by adding EO to a block after adding PO to glycerin Polymer polyol (polymer content 20%).

(9) Catalyst E-1: Dipropylene glycol solution of triethylenediamine [TEDA-L33 manufactured by Tosoh Corporation]
(10) Catalyst E-2: Dipropylene glycol solution of bis (N, N-dimethylamino-2-ethyl) ether [TOYOCAT-ET manufactured by Tosoh Corporation]
(11) Catalyst E-3: Tetramethylhexamethylenediamine (12) Catalyst E-4: Tetramethylethylenediamine (13) Foam stabilizer F-1: Polyether-modified dimethylsiloxane foam stabilizer [Toray Dow Corning Silicone ( SH-193]
(14) Foam stabilizer F-2: polyether-modified dimethylsiloxane foam stabilizer [L-5309 manufactured by Nihon Unicar Co., Ltd.]
(15) Polyisocyanate C-1: Polymethylene polyphenylene polyisocyanate [MR-200 manufactured by Nippon Polyurethane Co., Ltd.], NCO% = 31.0
(16) Polyisocyanate C-2: TDI [T-80 manufactured by Nippon Polyurethane Co., Ltd.], NCO% = 48.3

Examples 1-2 and Comparative Examples 1-2
Using a high pressure foaming machine (MiniRIM machine manufactured by PEC), the mixture of components other than polyisocyanate (C) and (C) shown in Table 1 was adjusted to 25 ° C., and then impact-mixed. It was poured into a 300 × 300 × 20 mm hermetic mold whose temperature was adjusted to ° C. and molded.
Among the foams obtained by demolding after 3 minutes, for the rigid polyurethane foams of Examples 1 and 2, using a sword mountain with a needle having a diameter of 1 mm, the surface high-density layer (X1 ′) on one side, The holes were formed so that the distribution of the holes was uniform and the total surface area of the holes was 5% (45 cm ² ) with respect to the surface area (900 cm ² ) of the surface high-density layer.

  Table 1 shows the measurement results of the physical property values of each foam. The density was measured according to JIS K 6400 (1997 edition). The sound absorption coefficient and the compressive stress are measured by the above methods.

  From the above results, the rigid polyurethane foams of Examples 1 and 2 of the present invention have a suitable range in the entire region of frequencies 1500 Hz to 4000 Hz and in the entire region of 800 Hz to less than 1500 Hz, compared to the foam of Comparative Example 1. It can be seen that it has sound absorbing performance and is excellent as a sound absorbing material. Moreover, it has a compressive stress of the suitable range compared with the foam of the comparative example 2, and it turns out that it is excellent in buckling performance.

  Since the rigid polyurethane foam of the present invention has a good sound insulation performance, it can be widely used as a sound insulation material for vehicles, building materials and the like. Further, the sound-absorbing and sound-absorbing material comprising the rigid polyurethane foam of the present invention and, if necessary, a skin material (for example, the foam and the skin material are preferably integrally molded by the above-described method) is used for a vehicle, particularly for an automobile underbody. It is suitably used as a sound absorbing material.

Claims (12)

A rigid polyurethane foam comprising three layers, a surface high-density layer (X1), an internal low-density layer (Y1), and a surface high-density layer (X2), wherein (X1) has pores penetrating the layer. The rigid polyurethane foam according to claim 1, wherein the average maximum diameter of the pores is 0.01 to 100 mm, and the total area of the pores on the surface of (X1) is 1 to 80% with respect to the surface area of (X1). The rigid polyurethane foam according to claim 1 or 2, wherein the thicknesses of (X1) and (X2) are each 0.5 mm or more. The portion excluding the hole of (X1) and the density of (X2) are 100 to 300 kg / m ³ , and the density of (Y1) is 10 to 70 kg / m ³ . Rigid polyurethane foam. Surface high-density layer (X1 '), internal low-density layer (Y1), and surface high-density layer formed by pouring a single foam-forming composition containing a water-based foaming agent into a mold in one step The rigid polyurethane foam according to any one of claims 1 to 4, wherein pores having an average maximum diameter of 0.1 to 100 mm are formed in a layer (X1 ') of the three layers of (X2). 6. The rigid polyurethane foam according to claim 5, wherein the means for making a hole in (X1 ') is a physical post-processing. The rigid polyurethane foam according to any one of claims 1 to 6, wherein the sound absorption coefficient is 45% or more in the entire region having a frequency of 1500 Hz to 4000 Hz. The rigid polyurethane foam according to any one of claims 1 to 7, wherein the sound absorption coefficient is 15% or more in the entire region of 800 Hz or more and less than 1500 Hz. The foam-forming composition comprises the following polyol component, polyisocyanate component (C), a foaming agent (D) mainly composed of water, a catalyst (E), and, if necessary, a foam stabilizer (F). The rigid polyurethane foam according to any one of the above.
Polyol component: a polyol comprising polymer polyol (A) and / or polyol (B) obtained by polymerizing vinyl monomer (b) in polyol (a) and containing alkanolamine (a1) in (B) component. The rigid polyurethane foam according to claim 9, further comprising the following (a2) and (a3) in (a) and / or (B).
(A2): Polyoxypropylene polyol having an average functional group number of 2 to 7 and a hydroxyl value of 200 to 600 mg / KOH.
(A3): (Polyoxyethylene) polyoxypropylene polyol having an average number of functional groups of 2 to 5, a hydroxyl value of 20 to 80 mgKOH / g, and a content of oxyethylene units of 0 to 70% by mass. A sound absorbing material comprising the rigid polyurethane foam according to any one of claims 1 to 10. The sound-absorbing material according to claim 11, wherein the sound-absorbing material is integrally formed with the skin material.