JP4485979B2 - Flame-retardant soundproofing / vibration-proof material for vehicle and manufacturing method thereof - Google Patents

Description

  The present invention relates to a flame-retardant soundproofing / vibration-proof material for a vehicle and a method for producing the same, and in particular, a soundproofing / vibration-proofing composed of a flexible polyurethane foam having excellent heat resistance and flame retardancy and low compression residual strain The present invention relates to a material and a method for advantageously producing such a soundproof / vibration-proof material.

  Conventionally, various types of soundproofing materials have been used in vehicles such as automobiles in order to reduce noise leaking outside the vehicle or in the passenger compartment. For example, in the engine room of a vehicle, the engine that is the source of the noise is used. Around the engine cover, side cover, oil pan cover, under cover, etc., to fix the foam sound such as foamed rubber or urethane foam to rigid members such as metal plates, etc. It is provided in a structure that is damped (see FIG. 1 of Patent Document 1). In addition, since various accessory devices and parts are arranged close to the periphery of the engine body of the vehicle, there is inevitably a gap between the engine body and these devices and parts. However, in such a structure, when the engine is operated, a standing wave is generated in the gap, and this standing wave causes a problem that the engine noise is increased. For this reason, in order to suppress such standing waves and reduce the radiated sound from the engine, in Patent Document 2 and the like, a gap (space) between the engine body and the surrounding devices and parts is used. It has been proposed that a cushioning material made of a foamed material such as foamed rubber or urethane foam is filled as a spacer.

  By the way, the material such as foamed rubber and foamed urethane used as a soundproofing material or a cushioning material as described above has a heat resistance deterioration property and a flame resistance property due to a special condition that it is disposed close to the engine body. Although it is desired to be excellent in both, the EPDM foam conventionally used as foamed rubber has good heat resistance, but has insufficient flame retardancy In addition, in the foam of epichlorohydrin rubber, which is another foam rubber, the flame retardancy is good but the heat deterioration resistance is insufficient.

  As foamed urethane (polyurethane foam) used in the same manner as such foamed rubber, asphalt-impregnated polyurethane foam foamed with asphalt is known as disclosed in Patent Document 3, Patent Document 4, and the like. . Specifically, this asphalt-impregnated polyurethane foam is produced by injecting a composition comprising a polyol, a polyisocyanate, a foaming agent, an amine catalyst, a flame retardant, and asphalt into a predetermined mold and foam-molding the composition. The asphalt-impregnated polyurethane foam thus obtained has a feature of being reasonably inexpensive and excellent in heat resistance, but has a problem of insufficient flame retardancy. However, if the content of the flame retardant in the polyurethane foam is increased, the flame retardancy is improved, but in addition to the inevitable increase in raw material costs, the heat deterioration resistance is reduced and the foam is reduced. Therefore, it is difficult to adopt an embodiment in which the content of the flame retardant is increased.

  Furthermore, in Patent Document 5, a flame retardant-containing flame retardant urethane foam containing a flame retardant obtained using a styrene polymer polyol as a polyol component is clarified, but in combination with a flame retardant, Since it is intended to achieve both flame retardancy and heat deterioration resistance of polyurethane foam, its cost reduction was difficult, and its heat deterioration resistance was evaluated at a temperature of 120 ° C. Therefore, if it exceeds such a temperature, the flame retardant contained in the foam will be scattered, the flame retardancy will be impaired, and the heat-resistant deterioration characteristics of polyurethane foam will be reduced. The problem was inherent.

  Furthermore, in Patent Document 6, a vehicle vibration-absorbing and sound-absorbing member having excellent vibration damping and sound absorbing properties and water-stopping properties is used, and a polyolefin polyol having a saturated hydrocarbon resin skeleton as a polyol component is used. It has been clarified that a foam (polyurethane foam) obtained by reacting with an organic polyisocyanate component in the presence of a surfactant having a group-containing fatty acid ester skeleton is used. It has not been clarified as to what means should be adopted in order to simultaneously impart excellent flame retardancy and heat deterioration resistance to polyurethane foam.

  Under such circumstances, the present inventors, together with other inventors, previously described in Patent Document 7 by using a specific organic polyisocyanate component and a specific polyol component, specifically, organic polyisocyanate. The main component is a monomeric MDI having an NCO content of 29 to 33%, which includes diphenylmethane diisocyanate and its carbodiimide modified product and / or its uretonimine modified product, and contains 1 to 1 in the monomeric MDI. While using 45% by weight of 2,4′-diphenylmethane diisocyanate as a monomer and / or modified component, the polyol component has a functional group number of 2 to 8 and a molecular weight: What contains 1000-10000 polyol in the ratio of 50 weight% or more By there, without using a flame retardant, and maintain excellent physical properties before and after heat aging test, and non-flammable, flexible polyurethane foams having excellent moldability revealed that the obtained.

  As a result, various problems such as an increase in product cost based on a large amount of conventional flame retardants can be advantageously solved. In vibration materials, the use of carbodiimide-modified diphenylmethane diisocyanate and / or its uretonimine-modified (hereinafter referred to as carbodiimide-modified) tends to sag, resulting in increased compression residual strain. However, it was newly revealed. In addition, by using a carbodiimide modified body of diphenylmethane diisocyanate and the like, it has become possible to reduce the cost compared to the case where a large amount of flame retardant is blended, but a modified body such as a carbodiimide modified body, The actual situation is that raw material costs are higher than other polyisocyanate compounds, and further cost reduction is required.

JP 2000-220467 A Japanese Utility Model Publication No.59-7545 Japanese Examined Patent Publication No. 57-22051 Japanese Patent Publication No. 61-50965 JP-A-7-233236 JP-A-10-81142 JP 2003-97645 A

  Here, the present invention has been made in the background of such circumstances, the problem to be solved is to achieve both excellent flame retardancy and excellent heat deterioration resistance, and to achieve compression residual. The purpose is to provide a flame-retardant soundproofing / vibration-proof material for vehicles with improved distortion characteristics and lower costs, and to advantageously produce soundproofing / vibration-proof materials with such excellent characteristics. It is to provide a possible method.

  And, as a result of intensive studies to solve such problems, the present inventors, as a result, the specific polyisocyanate component and the specific polyol component filed earlier without using a carbodiimide-modified product having a high raw material cost. In particular, it has been found that the compression residual strain characteristics can be effectively improved by replacing the constituent components of the polyisocyanate component.

Accordingly, the present invention has been completed based on such findings, and the first aspect thereof is a soft polyurethane obtained by reacting and foaming an organic polyisocyanate component and a polyol component. 75 to 90% by weight of a monomeric MDI comprising a foamed soundproof / vibration-proof material, wherein the organic polyisocyanate component contains (A) 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate And (B) 8 to 24.9% by weight of a polynuclear isocyanate composed of a polymeric MDI composed of crude MDI having three or more benzene rings in the molecule, and (C) 0.8% of the prepolymerized isocyanate. 1 to 2% by weight, and the (A) monomeric MDI contains 40% by weight or more. The polyol component contains 2,4'-diphenylmethane diisocyanate while the polyol component contains a polyol having a functional group number of 2 to 8 and a molecular weight of 1000 to 10,000 in a proportion of 50% by weight or more. The polyurethane foam has a density of 70 to 150 kg / m ³ , a 50% compression load value of (5 to 60) × 10 ⁻² N / mm ² , a tensile strength of 120 kPa or more, an elongation of 100% or more, and a compression residue. A flame-retardant soundproofing / vibration-proof material for a vehicle having a strain of 15% or less and exhibiting nonflammability by the FMVSS-302 flammability test method before and after a heat aging test at 160 ° C. for 72 hours is there.

  In addition, in the desirable second aspect of the flame retardant soundproofing / vibration-proof material for vehicles according to the present invention, the NCO content of the organic polyisocyanate component is adjusted to 31.0-33.5%. It becomes.

  Moreover, in the third aspect of the flame-retardant soundproofing / vibration-proof material for vehicles according to the present invention, the polyurethane foam has a tensile strength and elongation rate after a heat aging test of 160 ° C. × 72 hours, It has the characteristic which is 50% or more of the value before this test.

  Furthermore, in the fourth aspect of the flame-retardant soundproofing / vibration-proof material for vehicles according to the present invention, the monomeric MDI is composed of 2,4′-diphenylmethane diisocyanate and 4,4′-diphenylmethane diisocyanate. The 2,4'-diphenylmethane diisocyanate is contained in Meric MDI in a proportion of 40 to 50% by weight.

In addition, in a fifth aspect of the vehicle flame retardant soundproofing vibration-proof material according to the present invention, the polynuclear isocyanate, while the previous SL organic polyisocyanate component, the proportion of 8.5 to 19.5 wt% The structure used is preferably employed.

By the way, the present invention is also intended for a method for producing a flame-retardant soundproofing / vibration-proof material for vehicles, and is a soft product obtained by reacting and foaming an organic polyisocyanate component and a polyol component. In producing a desired soundproofing and vibration isolating material using polyurethane foam, 75 of Monomeric MDI containing (A) 2,4′-diphenylmethane diisocyanate and 4,4′-diphenylmethane diisocyanate as the organic polyisocyanate component. ~ 90 wt%, (B) 8 to 24.9 wt% of polynuclear isocyanate composed of polymeric MDI consisting of crude MDI having 3 or more benzene rings in the molecule, and (C) prepolymerization 0.1 to 2% by weight of isocyanate, and (A) monomeric MDI contains 40% by weight or more of On the other hand, a polyol containing 2,4′-diphenylmethane diisocyanate is used, and the polyol component contains a polyol having a functional group number of 2 to 8 and a molecular weight of 1000 to 10,000 in a proportion of 50% by weight or more. Using these materials, the organic polyisocyanate component and the polyol component are reacted so that the NCO / OH index is 0.6 to 1.2, whereby the density is 70 to 150 kg / m ³ and the compression is 50%. The load aging is (5-60) × 10 ⁻² N / mm ² , the tensile strength is 120 kPa or more, the elongation is 100% or more, the compressive residual strain is 15% or less, and the heat aging property is 160 ° C. × 72 hours. Before and after the test, the flexible polyurethane foam showing nonflammability was formed by the FMVSS-302 flammability test method. The first aspect is a method for manufacturing a flame-retardant soundproofing / vibration-proof material for vehicles.

  In the second preferred embodiment of the method for producing a flame-retardant soundproofing / vibration-proof material for vehicles according to the present invention, the reaction between the organic polyisocyanate component and the polyol component is performed in the presence of a foaming agent. The polyurethane foam will be formed.

  And according to the first aspect described above in the flame-retardant soundproofing / vibration-proof material for vehicles according to the present invention, the polyurethane foam that provides the flame-retardant soundproofing / vibration-proofing material for vehicles has a specific organic polyisocyanate component and It has a great feature in that it is formed by using specific polyol components and reacting them, where the activity and crosslinking properties of organic polyisocyanate components and the activity and crosslinking properties of polyol components Is effectively balanced to maintain excellent physical properties before and after the thermal degradation test, as well as good nonflammability (combustion resistance) and excellent compression residual strain characteristics. A polyurethane foam could be obtained.

  In particular, in the present invention, as the organic polyisocyanate component, (A) monomeric MDI containing 2,4′-form and 4,4′-form of diphenylmethane diisocyanate (MDI) in a specific ratio, B) A polynuclear isocyanate having three or more aromatic rings (nuclei) in the molecule and (C) a prepolymerized isocyanate are used in combination at a specific blending ratio. As a result, the compressive residual strain characteristics can be advantageously improved. In addition, the heat-resistant deterioration characteristics of the foam are effectively improved, and even if the flame comes into contact with the foam, the foam melts away by heat, and the non-flammable characteristics that prevent the flame from propagating are flame retardants. And carbodiimide modified products can be effectively imparted without requiring blending.

  Therefore, in the present invention, the occurrence of compression residual strain that has been caused when using a modified carbodiimide or the like can be effectively prevented. In order to make the anti-vibration material incombustible, it is not necessary to include any flame retardant in the foam that gives it, and since no carbodiimide modified product is used, a large amount of conventional flame retardant is blended. It is possible to advantageously eliminate various problems caused by the problem, and to reduce the cost of the product extremely effectively.

  In addition, according to the second aspect of the flame-retardant soundproofing / vibration-proof material for vehicles according to the present invention, the features of the present invention can be exhibited more advantageously.

  Further, in the third aspect of the vehicle flame-retardant soundproofing / vibration-proof material according to the present invention, very excellent heat aging resistance is imparted.

  Furthermore, according to the fourth aspect of the vehicle flame-retardant soundproofing / vibration-proof material according to the present invention, it is possible to effectively improve the compression residual strain characteristics.

  In addition, according to the above-described fifth aspect of the flame-retardant soundproofing / vibration-proof material for vehicles according to the present invention, a polynuclear isocyanate adopting a crude MDI having three or more benzene rings in the molecule, such a polynuclear If the content of the isocyanate is adjusted, the object of the present invention will be realized more advantageously.

  Further, according to the method for manufacturing a flame-retardant soundproofing / vibration-proof material for vehicles according to the present invention, the flame-retardant soundproofing / vibration-proofing material for vehicles having the excellent characteristics as described above can be formed with good moldability. In addition, it is easy to manufacture, and it is possible to form a soundproof / vibration-proof material at a low cost.

  Furthermore, in the second method for producing a flame-retardant soundproofing / vibration-proof material for vehicles according to the present invention, the reaction of polyurethane formation and foaming can be realized at the same time, and the soundproofing / vibration-proofing material comprising the desired polyurethane foam However, it can be effectively molded.

  By the way, in this invention, as an organic polyisocyanate component which is one of the reaction components for forming the flexible polyurethane foam which gives the target flame-retardant soundproofing and vibration-proof material for vehicles, as (A) 2,4 75-90% by weight of monomeric MDI containing '-MDI and 4,4'-MDI, (B) 8-24.9% by weight of polynuclear isocyanate, and (C) 0.1% of prepolymerized isocyanate. And 2% by weight of 2,4′-MDI is used in the monomeric MDI at a ratio of 40% by weight or more.

  Here, the monomeric MDI (component A) constituting the organic polyisocyanate component is a combination of 2,4′-form and 4,4′-form, which are isomers of MDI. In the invention, it is necessary that 2,4′-MDI is contained in such a monomeric MDI in a proportion of 40% by weight or more. In addition, 2,4'-MDI may be contained in monomeric MDI more than 4,4'-MDI. However, in the production of MDI, only 2,4'-MDI is used. It is difficult to obtain by itself. At present, the upper limit of the production ratio of 2,4′-MDI to 4,4′-MDI is substantially about 50/50. The upper limit of the content of MDI in monomeric MDI is generally about 50% by weight. In addition, when the content of 2,4′-MDI in the monomeric MDI is less than 40% by weight, it is difficult to improve the compressive residual strain characteristics, or the elongation is increased before and after the heat resistance deterioration test. The physical properties such as are reduced.

  In the present invention, the monomeric MDI containing the 2,4′-form and the 4,4′-form as described above is 75 to 90 wt%, preferably 80 to 90 wt% in the organic polyisocyanate component. % Is contained at a rate of%. In addition, if the content of the monomeric MDI in the organic polyisocyanate component is too small, the resulting foam tends to burn easily, and if too much, the combustion resistance is ensured well, It becomes inferior to compression residual strain characteristics.

As the polynuclear isocyanate (B component) constituting the organic polyisocyanate component, various known polyisocyanate compounds having three or more aromatic rings (nuclei) in the molecule are appropriately selected and used. Although the possible is, in particular, in the present invention, among them, having three or more benzene rings polymeric MDI consisting of (hence, the NCO group 3 or more with) crude MDI becomes the be needed use . The upper limit of the number of nuclei (number of benzene rings) in the crude MDI molecule is not particularly limited, but is generally about 6, and in the present invention, such number of nuclei (3-6) ) Is advantageously employed. Then, by utilizing the cross-linking characteristics of such polynuclear isocyanate, a foaming reaction is performed to form a target polyurethane foam.

  In the present invention, such a polynuclear isocyanate is contained in the organic polyisocyanate component in an amount of 8 to 24.9% by weight, preferably 8.5 to 19.5% by weight. . When the content of the polynuclear isocyanate in the organic polyisocyanate component is less than 8% by weight, it becomes difficult to sufficiently improve the compression residual strain characteristics of the polyurethane foam, whereas 24.9% by weight. When it exceeds the range, the combustion resistance is lowered and the fuel tends to burn.

  Furthermore, the prepolymerized isocyanate (C component) constituting the organic polyisocyanate component is obtained by reacting a polyisocyanate compound with a polyol according to a conventionally known method, and has two or more, preferably three NCO groups. For example, a prepolymerized isocyanate having three urethane bonds can be exemplified by reacting the above MDI with a trifunctional polyol. In particular, in the present invention, an isocyanate-terminated prepolymer formed by reacting a trifunctional ether-based polyol with MDI is suitably employed. Here, the trifunctional ether-based polyol is not particularly limited, and for example, a molecular weight of about 6000, which is formed by bonding three polyether groups (having an OH group at the end) having a molecular weight of about 2000. These polyols can be mentioned. By including such a prepolymerized isocyanate, the crosslinked form of the foam is improved, and compression residual strain characteristics and heat aging resistance are improved.

  In the present invention, such prepolymerized isocyanate is contained in the organic polyisocyanate component in a proportion of 0.1 to 2% by weight, preferably 0.5 to 1.5% by weight. . In addition, when the content of the prepolymerized isocyanate in the organic polyisocyanate component is less than 0.1% by weight, the obtained polyurethane foam is easily sag and can improve the compression residual strain characteristics. On the other hand, if it exceeds 2% by weight, deterioration of combustion resistance is caused.

  Thus, the organic polyisocyanate component contains the components A, B and C as described above in the proportions of 75 to 90% by weight, 8 to 24.9% by weight and 0.1 to 2% by weight, respectively. What has been done will be used. In the present invention, those composed only of the A component, the B component and the C component can be advantageously employed as the organic polyisocyanate component. However, the useful functions and effects of the present invention are adversely affected. As long as there is no limit, those obtained by appropriately blending other known polyisocyanate compounds other than the A component, the B component and the C component can also be used.

  And in this invention, in the organic polyisocyanate component comprised by various polyisocyanate compounds as mentioned above, the NCO content is in the range of 31.0-33.5% on a weight basis. It is prepared so that. This is because if the NCO content of such an organic polyisocyanate component is lower than 31.0%, the foam may easily burn, and the realization of a ratio exceeding 33.5% When adopting the above-mentioned blending ratio, it is difficult.

  As described above, in the present invention, the resin (polyurethane foam) obtained by using the organic polyisocyanate component containing the components A to C as described above in a special blending ratio is excellent. In addition to realizing heat-resistant deterioration characteristics, it exhibits the feature that it does not burn before and after the heat-resistant deterioration test without using a flame retardant or a modified carbodiimide. Here, the fact that it does not burn is a judgment result based on the FMVSS (Federal Motor Vehicle Safety Standards) -302 test standard. Is melted away by heat, and the flame does not propagate, so the determination is “non-combustible”. That is, since the speed at which the foam melts is faster than the speed at which the flame propagates, the polyurethane foam obtained according to the present invention has the property of not burning. Moreover, the polyurethane foam according to the present invention thus obtained has good compressive residual strain characteristics, specifically, the compressive residual strain is 15% or less, and has significant features. It is doing.

  On the other hand, in the present invention, as a polyol component that reacts with such an organic polyisocyanate component to form a target polyurethane foam, a polyol having a functional group number of 2 to 8 and a molecular weight of 1000 to 10,000 is 50% by weight or more. What is contained in proportions is used, whereby the above-described reaction of polyurethane formation with the organic polyisocyanate component can be effectively carried out to advantageously form a non-flammable flexible polyurethane foam. In addition, when the number of functional groups of such a polyol is less than 2, chain reaction with the organic polyisocyanate component is interrupted, resulting in problems such as difficulty in forming a polymer and impossible to form a foam, On the other hand, when the number of functional groups exceeds 8, problems such as extremely reduced elongation of the resulting foam are caused. If a polyol having a molecular weight of less than 1000 is used, the foam becomes hard and loses elasticity, making it difficult to obtain the properties of a flexible foam. If a polyol having a molecular weight exceeding 10,000 is used, the viscosity increases, and It makes the reaction with the isocyanate component and the foaming process difficult. Then, by making the polyol having the number of functional groups and molecular weight occupy a ratio of 50% by weight or more of the polyol component, the reaction with the organic polyisocyanate component that gives the target polyurethane foam is advantageously advanced. To get.

  In addition, as such a polyol having the number of functional groups and molecular weight, those conventionally known can be appropriately selected and used. For example, polyhydric hydroxy compounds, polyether polyols, polyester polyols, polymer polyols can be used. , Polyether ester polyols, polyether polyamines, polyester polyamines, alkylene polyols, urea dispersed polyols, melamine modified polyols, polycarbonate polyols, acrylic polyols, polybutadiene polyols, phenol modified polyols, etc. It is selected from various known polyols and used alone or in combination.

And the flame-retardant soundproofing / vibration-proof material for vehicles according to the present invention is a flexible polyurethane foam obtained by reacting and foaming a specific organic polyisocyanate component and a specific polyol component as described above. In particular, the flexible polyurethane foam has a density of 70 to 150 kg / m ³ and a 50% compression load value (at the time of 50% compression) in order to be used advantageously as a vehicle soundproofing and vibration damping material. The load per unit area: ASTM-D-3574) is (5-60) × 10 ⁻² N / mm ² , the tensile strength is 120 kPa or more, and the elongation is 100% or more. Become.

In such a flexible polyurethane foam, if the foam density is less than 70 kg / m ³ , physical properties such as compression residual strain characteristics cannot be expected to be sufficiently improved, and the strength is insufficient. On the other hand, if it exceeds 150 kg / m ³ , the product weight increases, which is disadvantageous in terms of weight reduction of the vehicle. Further, the 50% compressive load value indirectly indicates the hardness of the polyurethane foam, and when it becomes lower than 5 × 10 ⁻² N / mm ² , such foam is used as a gap filling member. At this time, there is a problem that it is difficult to fit into such a gap, or the drop-out from the gap is likely to occur, and in the case of hardness exceeding 60 × 10 ⁻² N / mm ^2. However, it becomes too hard and it becomes difficult to fill the gap, and the problem of not being able to sufficiently exhibit the soundproofing effect is caused. Furthermore, if the tensile strength or elongation rate is too low, the product may be destroyed when it is installed as a product in a predetermined place, and the shape cannot be maintained until the end of the vehicle life. From the point of causing problems, the tensile strength and elongation must be equal to or greater than the specified values described above.

  In addition, such polyurethane foam has excellent characteristics as described above by an appropriate balance between the activity and crosslinking characteristics of the specific organic polyisocyanate component as described above and the activity and crosslinking characteristics of the polyol component described above. It will be a thing.

  Further, such a polyurethane foam advantageously has a characteristic that the tensile strength and elongation after the heat aging test at 160 ° C. for 72 hours are both 50% or more of the values before the test. It is desirable to be prepared. As described above, by maintaining excellent physical properties before and after the heat resistance deterioration test, the function as a vehicle soundproofing / vibrationproofing material can be exhibited for a longer period of time.

  Further, when producing the flame-retardant soundproofing / vibration-proof material for vehicles according to the present invention, the specific organic polyisocyanate component and the specific polyol component described above are reacted and foamed in a suitable foaming mold. Thus, a soundproofing / vibration-proofing material comprising a polyurethane foam (foam) having a desired shape can be formed. In this case, a known catalyst is used for the organic polyisocyanate component or polyol component as in the conventional case. , A crosslinking agent, a foaming agent, a foam stabilizer, a chain extender, a viscosity reducing agent, and the like are appropriately added as additives.

  As the catalyst, known amine catalysts, organometallic catalysts, and the like are used. Specifically, bis (dimethylaminoethyl) ether, pentamethyldiethylenetriamine, N, N-dimethylcyclohexylamine, N, N— Dimethylethanolamine, N, N, N ′, N′-tetramethylhexamethylenediamine, N, N, N ′, N′-tetramethylpropylenediamine, N, N, N ′, N′-tetramethylethylenediamine, tri Examples include ethylenediamine, N-methyl-N ′-(dimethylamino) ethylpiperazine, N-methylmonoforin, N-ethylmonoforin, triethylamine, and the like, and examples of organometallic catalysts include tin laurate and tin octoate. Etc. can be mentioned.

As the foaming agent, known water is preferably used. However, other than water, methylene chloride, chlorofluorocarbon, CO ₂ gas, and the like can also be used as the foaming agent. The amount of the foaming agent used is determined empirically so as to obtain the density as described above, and is used in an amount similar to the amount used in the production of a conventional polyurethane foam. For example, in the case of water as a blowing agent, it is generally used in a ratio of about 1 to 6 parts by weight with respect to 100 parts by weight of the polyol component.

  Furthermore, the cross-linking agent is appropriately selected from small cross-linking agents having a relatively low molecular weight depending on the hardness. For example, diol, triol, polyvalent amine, or ethylene oxide or propylene oxide is added to these. And the like, triethanolamine, diethanolamine and the like. In addition, as a foam stabilizer, a typical silicone foam stabilizer for producing polyurethane foams can be cited as typical examples thereof. For example, SRX-274C manufactured by Toray Dow Corning Co., Ltd., manufactured by Nihon Unicar Co., Ltd. No. L-5390, SZ1313, B-4113 manufactured by Goldschmidt, Inc., and the like are commercially available.

  In addition to the above-described blending components, flame retardants, fillers, antistatic agents, colorants, stabilizers, etc., as required, do not depart from the purpose of the present invention, depending on the performance required for the foam. To some extent, it will be added.

  When producing the desired polyurethane foam, usually, a predetermined amount of water, a catalyst, a foam stabilizer and other auxiliaries as foaming agents are mixed in advance with the specific polyol component described above. Then, using the prepared resin premix (premix polyol), a specific organic polyisocyanate component as described above is mixed and reacted, and further foamed. Specifically, such a resin premix and an organic polyisocyanate component are mixed using a known urethane foaming machine with an NCO / OH index (equivalent ratio) of 0.6 to 1. 2 and preferably 0.9 to 1.1, and more preferably 1 and the mixture is poured into a predetermined mold, reacted and foamed to form a polyurethane foam of the desired shape. It is.

  In the reaction between the organic polyisocyanate component and the polyol component, if the NCO / OH index is less than 0.6, there is a problem that the physical properties are deteriorated, and if it exceeds 1.2, the crosslinking reaction proceeds. As a result, the foam easily burns, the curing property is poor, and the foam is poorly moldable.

  The flexible polyurethane foam thus obtained can be advantageously used as a flame-retardant soundproofing / vibration-proof material according to the present invention. For example, the flexible polyurethane foam is disposed around the engine in the engine room of a vehicle. Used to reduce engine noise, engine cover, side cover, oil pan cover, under cover, hood silencer, dashboard silencer, etc. It is advantageously used as a spacer that fills the space formed between them and suppresses standing waves generated therebetween.

  Examples of the present invention will be shown below to clarify the present invention more specifically. However, the present invention is not limited by the description of such examples. Needless to say. In addition to the following examples, the present invention includes various descriptions based on the knowledge of those skilled in the art without departing from the gist of the present invention, in addition to the descriptions in the embodiments of the present invention described above. It should be understood that other changes, modifications, improvements, etc. may be made.

  First, PPG (manufactured by Sanyo Chemical Industries, Ltd., average molecular weight = 6000, number of functional groups = 3) is used as a polyol component, and 100 parts by weight of diethylene glycol (DEG) as a crosslinking agent and water as a blowing agent. , Amine catalyst (manufactured by Kao Corporation, triethylenediamine), silicone-based foam stabilizer (manufactured by Nihon Unicar Co., Ltd.), pigment (manufactured by Dainichi Seika Kogyo Co., Ltd., carbon black), respectively, in the proportions shown in Table 1 below Was added to prepare a premix polyol.

  On the other hand, as the polyisocyanate, 4,4'-MDI and 2,4'-MDI, or three kinds of commercially available products having different composition compositions of crude MDI (polynuclear isocyanate) and prepolymerized MDI are used. Are appropriately selected and combined at a predetermined ratio to prepare various organic polyisocyanate components (compositions) according to Invention Examples 1 and 2 and Comparative Examples 1 to 4 having the compositions shown in Table 2 below. did. In addition, as the prepolymerized MDI, a prepolymer (molecular weight: about 6000) of trifunctional ether-based polyol and MDI was used.

  Next, using the prepared premix polyol and various organic polyisocyanate components, the premix polyol (POL) and the various organic polyisocyanate components (ISO) are respectively weighted so that the NCO / OH index is 1. In the ratio, POL: ISO was mixed at a ratio of about 7: 3. Then, it is poured into a predetermined mold (mold) at a raw material temperature of 22 ° C., and foamed and cured at a mold temperature of 52 ° C. and a curing time of 5 minutes. Various polyurethane foams (Invention Examples 1 and 2 and Comparative Examples 1 to 4) were obtained.

  The various polyurethane foams thus obtained were measured for their density, 50% compressive load value, tensile strength (TB) and elongation (EB), and the results are shown in Table 3 below. In addition, a 50% compressive load value is measured based on ASTM-D-3574.

  Further, for such polyurethane foam, each combustibility is evaluated based on the FMVSS-302 flammability test method, and in accordance with “7. Measurement method of compressive residual strain” of JIS-K-6400-1997, , Compress the load at a rate of 50%, maintain the state at 70 ° C. × 22 hours, then release the load and allow to cool at room temperature for a predetermined time to measure the thickness Thus, the compressive residual strain was determined, and the measured values obtained were shown in the column of sag resistance in Table 3 below, and from these values, the compressive residual strain characteristics were evaluated, and the results were also shown. In addition, the evaluation of the flammability by the FMVSS-302 flammability test method is carried out by holding the foam sample horizontally, applying a burner flame to one end of the foam sample for 15 seconds, and then evaluating the flammability after removing the flame. When the foam sample immediately self-extinguishes after evaluation according to the test method and removal of such a flame, it was judged as “pass”. The evaluation criteria for compressive residual strain characteristics were: ◎: 12% or less, ◯: more than 12%, 15% or less, Δ: more than 15%, 20% or less, and x: more than 20%.

  Further, the polyurethane foam was subjected to a heat aging test at 160 ° C. for 72 hours, and then subjected to a flammability test for each polyurethane foam. The obtained results are shown in Table 3 below, and heat aging is also performed. The tensile strength and elongation of each polyurethane foam after the test were measured. And the ratio of the tensile strength and elongation after a heat aging test with respect to the tensile strength and elongation at the time of normal was calculated, respectively, and it was shown in following Table 3 as TB retention (%) and EB retention (%). Moreover, heat aging resistance was evaluated from the values of the TB retention rate (%) and EB retention rate (%), and the results are also shown in Table 3 below. The evaluation criteria are: ◎: TB retention and EB retention are both 70% or more, ○: TB retention and EB retention are both 60% or more, and Δ: TB retention and EB retention are both 50% or more. X: TB retention and EB retention were both less than 50%.

  As is apparent from the results in Table 3, when the same polyol component (functional group number: 3, molecular weight: 6000) is used, 4,4'-MDI, 2,4'-MDI are used as the organic polyisocyanate component. In the polyurethane foam according to Examples 1 and 2 of the present invention obtained by using crude MDI and prepolymerized MDI in a specific blending ratio as described above, both have excellent flame retardancy and Excellent heat resistance deterioration is imparted, and further, compression residual strain characteristics can be secured well, and these polyurethane foams can be advantageously used as flame retardant soundproofing and vibration isolating materials for vehicles. I understand.

  In contrast, the polyurethane foams of Comparative Example 1 and Comparative Example 3 that contain a large amount of monomeric MDI and do not contain any prepolymerized MDI have sufficient compression residual strain characteristics. I understand that it is not. Moreover, in the comparative example 1, it is recognized that it is inferior also in heat aging resistance. Further, in Comparative Example 2 in which the content of prepolymerized MDI is large and Comparative Example 4 in which the content of crude MDI is large and the content of monomeric MDI is small, the flammability by the FMVSS-302 flammability test Inferior in evaluation, it is difficult to say that it has sufficient flame retardancy.

  In this example, various polyol components were prepared. That is, as the polyol component, PPG (1) (manufactured by Sanyo Chemical Industries, average molecular weight = 6000, number of functional groups = 3), polymer polyol (manufactured by Asahi Denka Kogyo Co., Ltd., average molecular weight = 6000, number of functional groups = 3), PPG (2) (manufactured by Sanyo Chemical Industries, average molecular weight = 6000, number of functional groups = 4) or PPG (3) (manufactured by Sanyo Chemical Industries, Ltd., average molecular weight = 7000, number of functional groups = 4), 100 With respect to parts by weight, diethylene glycol (DEG) as a crosslinking agent, water as a blowing agent, amine catalyst (manufactured by Kao Corporation, triethylenediamine), silicone-based foam stabilizer (manufactured by Nihon Unicar Corporation), pigment (Daiichi Chemical Black Co., Ltd., carbon black) was blended in the proportions shown in Table 4 below, and 5 types of premixed polyols were added. The a~e was prepared.

  On the other hand, as the polyisocyanate, 4,4′-MDI and 2,4′-MDI, or three types of commercial products having different compositions of crude MDI and prepolymerized MDI are used, and these are used at a predetermined ratio. By combining them, an organic polyisocyanate component a having the composition shown in Table 5 below was prepared. In addition, as the prepolymerized MDI, a prepolymer (molecular weight: about 6000) of trifunctional ether-based polyol and MDI was used. Moreover, the organic polyisocyanate component b which has a composition shown in following Table 5 containing the modified body (carbodiimide modified body and / or uretonimine modified body) for preparation was prepared.

  Then, using the premix polyols a to e prepared above and the organic polyisocyanate components a and b, the premix polyol (POL) and the organic polyisocyanate component (ISO) so that the NCO / OH index is 1. Were mixed in a weight ratio of approximately POL: ISO = 7: 3. After that, by pouring into a predetermined mold (mold) at a raw material temperature: 22 ° C., and foaming and curing at a mold temperature: 52 ° C. and a curing time: 5 minutes, a size of 120 mm × 120 mm × 60 mm is obtained. Various polyurethane foams (Invention Examples 3 to 6 and Comparative Example 5) were obtained.

  The various polyurethane foams thus obtained were measured for their respective densities, 50% compressive load values, TB and EB, and the results are shown in Table 6 below. In addition, the polyurethane foam was subjected to a flammability test in the same manner as in Example 1. On the other hand, the compression residual strain was measured, and the results obtained together with the evaluation of the compression residual strain characteristic are shown in Table 6 below.

  Further, the polyurethane foam was subjected to a heat aging test at 160 ° C. for 72 hours, and then subjected to a flammability test of each polyurethane foam, and the tensile strength and elongation were measured. The EB retention (%) was calculated, and the results are shown in Table 6 below. The evaluation criteria were the same as in Example 1 above.

  As is apparent from the results in Table 6, it can be seen that Comparative Example 5 including the carbodiimide modified product is inferior in compression residual strain characteristics. On the other hand, it is recognized that all of Examples 3 to 6 of the present invention have good compression residual strain characteristics, flame retardancy and heat deterioration resistance.

Further, in Invention Example 4 using a polymer polyol (average molecular weight = 6000, functional group number = 3), the tensile strength in a normal state was set to 329 kPa, and particularly excellent tensile strength was realized among Invention Examples 3 to 6. ing. Furthermore, in Example 5 of the present invention using PPG (2) (average molecular weight = 6000, number of functional groups = 4), the compression residual strain was 5%, and the compression residual strain characteristics particularly excellent among Examples 3-6 of the present invention. Is expressed. Furthermore, in Example 6 of the present invention using PPG (3) (average molecular weight = 7000, number of functional groups = 4), it is recognized that the TB retention and EB retention are high and the heat aging resistance is excellent.

Claims (7)

A soundproofing and vibration isolating material composed of a flexible polyurethane foam obtained by reacting and foaming an organic polyisocyanate component and a polyol component,
The organic polyisocyanate component is (A) 75 to 90% by weight of monomeric MDI containing 2,4′-diphenylmethane diisocyanate and 4,4′-diphenylmethane diisocyanate, and (B) three or more benzene rings in the molecule. Comprising 8 to 24.9% by weight of a polynuclear isocyanate composed of a polymeric MDI composed of crude MDI having (C), and 0.1 to 2% by weight of (C) a prepolymerized isocyanate, The (A) monomeric MDI contains 2,4′-diphenylmethane diisocyanate in a proportion of 40% by weight or more, while the polyol component is a polyol having a functional group number of 2 to 8 and a molecular weight of 1000 to 10,000. In a proportion of 50% by weight or more, and the polyurethane foam is further used. Is its density 70~150kg / m ^3, 50% compressive load value ^{(5~60) × 10 -2 N /} mm 2, a tensile strength of more than 120 kPa, 100% or more elongation, compressive residual strain 15 % Flame retardant soundproofing / vibration-proofing material for vehicles, which exhibits nonflammability by the FMVSS-302 flammability test method before and after a heat aging test at 160 ° C. for 72 hours.   The flame-retardant soundproof / vibration-proof material for vehicles according to claim 1, wherein the NCO content of the organic polyisocyanate component is adjusted to 31.0 to 33.5%.   The tensile strength and elongation rate of the polyurethane foam after a heat aging test at 160 ° C. for 72 hours are both 50% or more of the value before the test. Item 3. A flame-retardant soundproofing / vibration-proof material for vehicles according to Item 2.   The monomeric MDI is composed of 2,4′-diphenylmethane diisocyanate and 4,4′-diphenylmethane diisocyanate, and the 2,4′-diphenylmethane diisocyanate is contained in the monomeric MDI in a proportion of 40 to 50% by weight. The flame-retardant soundproofing / vibration-proof material for vehicles according to any one of claims 1 to 3, which is contained. The polynuclear isocyanate, while the previous SL organic polyisocyanate component, at a rate of 8.5 to 19.5 wt%, 1 to claim used flame vehicle according to any one of claims 4 Flammable soundproofing and vibration isolating material. In producing a desired soundproofing / vibration-proof material in a flexible polyurethane foam obtained by reacting and foaming an organic polyisocyanate component and a polyol component,
As the organic polyisocyanate component, (A) 75 to 90% by weight of monomeric MDI containing 2,4′-diphenylmethane diisocyanate and 4,4′-diphenylmethane diisocyanate, and (B) three or more benzene rings in the molecule Comprising 8 to 24.9% by weight of polynuclear isocyanate composed of polymeric MDI comprising crude MDI having (C) and 0.1 to 2% by weight of prepolymerized isocyanate, and (A) A monomeric MDI containing 2,4'-diphenylmethane diisocyanate in a proportion of 40% by weight or more is used, while the polyol component has a functional group number of 2 to 8 and a molecular weight of 1000 to 10,000. Those containing 50% by weight or more of a polyol The Aneto and polyol components, as NCO / OH index is 0.6-1.2, by reacting a density of 70~150kg / m ^3, 50% compressive load value (5-60 ) × 10 ⁻² N / mm ² , tensile strength is 120 kPa or more, elongation is 100% or more, compression residual strain is 15% or less, and FMVSS-302 before and after the heat aging test at 160 ° C. × 72 hours. A method for producing a flame-retardant soundproof / vibration-proof material for vehicles, wherein the flexible polyurethane foam exhibiting nonflammability is formed by a flammability test method.   The method for producing a flame-retardant soundproof / vibration-proof material for a vehicle according to claim 6, wherein the polyurethane foam is formed by performing the reaction between the organic polyisocyanate component and the polyol component in the presence of a foaming agent. .