JP2001026628A - Curable composition of polyurethane foam and preparation thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curable composition of a polyurethane foam which has an excellent preparation stability and a low content of gas-generating component, and a preparation process thereof, SOLUTION: A curable composition of a polyurethane foam having a low content of gas-generating component is prepared using a polyurethane foam obtained by allowing a polyol component to react with a composition containing a polyfunctional isocyanate in the presence of a foaming agent and a catalyst. Here, no organic tin catalyst is used, and a combination of (A) a reactive amine catalyst having within a molecule at least one hydroxy group or mercapto group which is reactive with polyfunctional isocyanates and (B) an amine catalyst which has an acid dissociation constant pKa of 9 or larger and allows strong gelation, is used. A foam obtained using the above-mentioned composition is heat-baked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a computer-related device such as a hard disk device or a CD-ROM device.
Alternatively, a curable composition of a polyurethane foam, a curable composition of a polyurethane foam, which has a low gas generating component suitable for a soundproofing material and a packing material for other electronic devices or clean rooms, and a polyurethane foam from the composition The present invention relates to a method for manufacturing a body, and a soundproofing material and a packing material for a computer-related device or another electronic device or a clean room using the foam.

[0002]

2. Description of the Related Art Conventionally, polyurethane foam has been used as a soundproofing material and packing material for computer-related equipment or for other electronic equipment or clean rooms. This polyurethane foam has a polyol component,
It is obtained by reacting a composition containing a polyfunctional isocyanate and a blowing agent in the presence of a catalyst or a catalyst and a foam stabilizer. Conventionally, catalysts for producing polyurethane foams have been used alone or in combination with organometallic catalysts, mainly tin-based catalysts, and amine catalysts.
Secondary amine compounds are preferably used. Silicone compounds are mainly used as foam stabilizers. However, conventional amine catalysts have various problems. That is, since the amine catalyst has a low boiling point, an irritating odor of these compounds may be generated during the production of the polyurethane foam or even after the product is produced. Further, the products obtained using these compounds bleed out the compounds remaining in the products and release volatile components to the outside air for a long time. For this reason, when used as a soundproofing material or packing material in a car cabin, it foggs the glass (fogging)
It is known that the use of an amine catalyst is not preferred because examples may occur. Further, in the case of a sound absorbing material or a packing material for electronic equipment, the generation of silicone used as a foam stabilizer itself causes an important problem, so that a silicone foam stabilizer may not be used. In order to solve this problem, it has been proposed to use an amine compound having a hydroxy group in the molecule as a catalyst (Japanese Patent Laid-Open Publication No.
-255120 etc.). The amine catalyst for producing urethane has an advantage that it has an extremely low odor and is a non-migrating catalyst in polyurethane resins.

[0003] However, the present inventors have proposed a polyurethane foam using only a non-migratory amine-based catalyst in applications requiring low gas-generating properties (simply low gas-generating properties) from foam products. If you manufacture your body,
We found the following problems. Since the gelling reaction is slower than the initial foaming reaction, a large amount of catalyst needs to be added. Since the initial foaming reaction is extremely fast, not only is it difficult to apply the reaction stock solution uniformly, but also the produced polyurethane foam is an inhomogeneous product in which streaks, unevenness, and the like are generated, and the product value is greatly impaired. When a comparatively thin (50 mm or less) polyurethane foam is continuously produced by a traverse method, a reverse coater method, or a die method, the reaction stock solution gels,
Since problems such as adhesion to the coating equipment occur, production with a small amount of added catalyst is indispensable. For this reason, when a product in which the gelation reaction of the product is insufficient is manufactured and stored in the form of a roll-shaped product or a single-plate cut and laminated product, the products adhere to each other (block), and it is difficult to obtain a good product. Further, even if a product that can be produced with a large amount of catalyst is obtained, a catalyst that could not be non-transferable remains in the product, which is not satisfactory as a reduction in gas generation components.

Therefore, a catalyst which uses a non-transferring type amine catalyst and an organotin-based catalyst in combination is widely used in the urethane industry. In this case, the effect of the combined use of the catalyst greatly reduces the amount of the non-transferring type catalyst. I can do it. By adjusting the amount of the catalyst added, the balance between the initial foaming reaction and the gelling reaction can be easily measured. The products to be manufactured have the following problems, although the gelation reaction has been increased and the problem of blocking can be solved, and the disadvantages of the non-transferable amine alone can be improved. That is, since the organotin-based catalyst does not have an active group that reacts with the polyfunctional isocyanate, it remains in the product as a transferable catalyst, so that this compound easily bleeds out to the product surface. Further, it is considered that the compound may be released from the product as a volatile component to the outside air for a long time in spite of its relatively high molecular weight. For this reason, when used as a sound absorbing material or packing material for electronic equipment, the organometallic catalyst easily bleeds out or vaporizes on the product surface, and contaminates during the work to be incorporated into the electronic equipment or the parts. In some cases, defective contacts and erroneous operations may occur. More recently,
Polyurethane foam is used as a soundproofing material for stepping motors and a light receiving device for laser printers. Polyurethane foam is also used as a gasket material for hard disk drives. However, in these applications, silicone foam stabilizers and organotin catalysts can cause abnormal reading of media, which is particularly problematic. Have been.

[0005] As a countermeasure, a method of performing a thermal baking treatment or the like to forcibly remove the compound bleed out to the product surface by thermal decomposition or a method of cleaning may be considered. However, in the former heat treatment, the treatment temperature is increased. Since the setting and the processing time take a long time, there is a problem that the product is thermally degraded. It is considered that it is technically very difficult to completely remove it. Even with the latter cleaning method, it is technically difficult to clean the inside of the product, which is a low-permeability packing material, even if the product surface can be cleaned. Even if the processing can be performed as described above, it is expected that a long processing time will be spent and the process will be complicated, so that it is not very realistic considering practicality.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present inventors have found that a polyurethane foam curable composition that has a slow initial foaming reaction and a fast gelling reaction is preferred. As a result of examining various catalysts based on the knowledge that it is, it is found that the use of a reactive amine catalyst and an amine catalyst having strong gelling reduces the amount of added catalyst and suppresses the gas generation component to a low level. The inventors have found that the present invention can be performed and completed the present invention. That is, the object of the present invention is to use a reactive amine catalyst and an amine catalyst having strong gelling together without using an organotin-based catalyst or the like, and without using a silicone foam stabilizer, without adding a catalyst. Small amount,
Also, to provide a curable composition for a polyurethane foam in which a gas component generated from a product is suppressed to a low level, and a soundproofing material and a packing material for a hard disk device comprising a polyurethane foam using the curable composition. It is.

[0007]

The gist of the present invention is to provide a polyurethane foam obtained by reacting a composition containing a polyol component and a polyfunctional isocyanate in the presence of a catalyst, as a catalyst (A). A reactive amine catalyst having at least one hydroxy group or mercapto group in a molecule that reacts with a polyfunctional isocyanate, and an amine catalyst having an acid dissociation constant pKa of 9 or more and strong gelling as the catalyst (B) are used in combination. It is a curable composition of a polyurethane foam in which a gas generating component is suppressed to a low level. That is, in a polyurethane foam obtained by reacting a composition containing a polyol component and a polyfunctional isocyanate in the presence of a catalyst, the above-mentioned catalyst (A) has a hydroxyl group or a mercapto group which reacts with the polyfunctional isocyanate. Polyurethane foam with low outgassing components by using a reactive amine catalyst having at least one group in the molecule and (B) an amine catalyst having an acid dissociation constant pKa of 9 or more and strong gelling in combination A body curable composition was obtained.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a curable composition for obtaining a polyurethane foam having a low gas generating component according to the present invention and a method for producing the same will be specifically described.
The reactive amine catalyst used in the present invention is, in particular, a tertiary amine compound represented by the following general formula (1),
By selecting from compounds having two or more carbon-carbon bonds in the bond between the nitrogen atom and the hydroxy group, it is possible to easily prepare the initial foaming reaction / gelation reaction with a small amount of addition and to reduce the gas generating component. It was found.

[0009]

Embedded image (Wherein, R is an alkyl group having 1 to 6 carbon atoms, and n represents an integer of 2 to 10) In the present invention, in the general formula (1), the carbon-carbon bond is an integer of 2 to 10 Wherein the carbon-carbon bond is 2
If the number is less than 2, the initial foaming reaction is stronger than the gelling reaction.
If the number is more than one, the initial foaming reaction is weakened and the gelling reaction is strengthened, so that uniform application of the reaction raw material is easy. If the number exceeds 10, the initial foaming reaction is weak and it is difficult to form fine cells (bubbles). There are drawbacks. Furthermore, a hydroxy group and carbon-
A compound in which a nitrogen atom or an oxygen atom is not interposed between carbon bonds is preferable, and a reactive tertiary amine compound having 6 carbon atoms is particularly preferable. The reason is not clear,
It is considered that as the number of carbon atoms increases, the affinity with the polyol increases, and the affinity with water decreases, thereby delaying the initial foaming reaction and increasing the gelling reaction. Compounds in which a nitrogen atom or an oxygen atom is interposed between the hydroxy group and the carbon-carbon bond are considered to increase the initial foaming reaction because the affinity for water increases.

Specifically, as the compound having a hydroxy group, N, N-dimethylethanolamine (DME
A), N, N-dimethylethoxyethanol, N, N-
Dimethylethoxyethoxyethanol, N, N-dimethylaminohexanol, N, N, N'-trimethylaminoethylethanolamine, N, N, N'-trimethylaminopropylethanolamine, N-methyl-N'-
Hydroxyethylpiperazine (MHEP), N, N,
N'N'-telolamethylhydroxypropyldiamine (TMHPDA) and the like, and compounds having a mercapto group include triazinethiol triazine-trithiol, butylaminotriazine-dithiol, hexylaminotriazine-dithiol, diethylaminotriazine-dithiol, Butoxyaminotriazine-dithiol; imidazole-based 1-methyl-5-mercapto-1,2,3,4tetrazole; and mixtures thereof. These catalysts are incorporated into the urethane resin and become non-migrating type, so that bleed out to the product surface and outgassing components can be suppressed low.

In the production of a polyurethane foam, a compound having a hydroxy group and a mercapto group is preferable as the reactive group, considering that the initial foaming reaction is slow and the gelation reaction is fast. However, when only these are used, gelling is delayed when the number of added portions is adjusted to satisfy the initial foaming reaction, and conversely, when the added amount is large enough to satisfy the gelling reaction, the initial foaming reaction is fast, so the reaction is Not only is it difficult to apply the undiluted solution uniformly, but also a heterogeneous product with streaks and unevenness in the manufactured polyurethane foam, which greatly impairs the product value, and the reaction undiluted solution gels and adheres to the coating device. There are problems such as the occurrence of problems during long-term continuous production, and the problem that unreacted catalyst remains and the amount of generated gas cannot be reduced. Thus, the object of the present invention is not satisfied. The present invention has made it possible to suppress the production stability and the amount of gas generating components by using a reactive amine catalyst and a highly gelling amine catalyst having a dissociation constant pKa of 9 or more.

When a tertiary amine catalyst having a dissociation constant pKa of less than 9 is selected, the initial foaming reaction has a low gelling reaction, which causes a problem in uniform application of the reaction raw materials in producing a polyurethane foam. Therefore, a large amount of the catalyst is required to enhance the gelation, so that a large amount of the transferable catalyst remains in the urethane resin, and it is difficult to reduce the amount of the gas generating component, which does not satisfy the present invention. . In the present invention, the initial foaming reaction / gelation reaction can be prepared by using and using the reactive amine catalyst (A) and the amine catalyst (B) having an acid dissociation constant pKa of 9 or more and having a strong gelation, It has been found that the amount of the gas generating component can be reduced because the amount of the catalyst added is small. The acid dissociation constant pKa is generally used as a guide to indicate the strength of the gelation reaction of an amine catalyst. It is considered that the larger the numerical value, the higher the gelation reaction.
The acid dissociation constant pKa was measured using an automatic potentiometric titrator (AT-310J, manufactured by Kyoto Electronics Industry Co., Ltd.), and 0.1 mol of a mixed solution with purified water adjusted to 0.1 mol equivalent of an amine catalyst. The pH at the half equivalent point was determined by titration with hydrochloric acid, and this was adopted as the pKa value. The measurement was performed at 25 ° C.

The amine catalyst having a strong gelation in the present invention not only can enhance the gelation reaction by adding a small amount because the gelation reaction is stronger than the initial foaming reaction, but also has a synergistic effect when used in combination with a reactive amine catalyst. It has been found that the effect can be exerted, so that the amount of catalyst added can be extremely small, but the reason is not clear. The strong gelling amine used in combination with the reactive amine catalyst is selected from imidazole-based, cyclic triazine-based, and cyclic amidine-based compounds having an acid dissociation constant pKa of 9 or more, so that the gelling reaction is initially foamed. Not only is it stronger than the reaction, it is possible not only to increase the gelling reaction by adding a small amount, but also to reduce the amount of the catalyst because a synergistic effect is exhibited when used in combination with the reactive amine catalyst.

The highly gelling amine catalyst used in the present invention is, in particular, a cyclic triazine-based tertiary amine catalyst having a boiling point of 150 ° C. or less, tris-dimethylpropyl-hexahydro-S-triazine or an organic acid salt thereof. It has been found that by using the same, it is possible to obtain a polyurethane foam having an extremely low outgassing component. Specifically, examples of the amine catalyst having a strong dissociation with a dissociation constant pka of 9 or more include 1-methyl-5-imidazole compound.
Mercapto-1,2,3,4 tetrazole, 2-methylimidazole, 2-ethyl-4-methylimidazole,
1-isobutyl-2-methylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-
Ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, and other cyclic amidine compounds DBUＤＢ1,8-diazabicyclo (5,
(4,0) undecene-7}, DBN {1,5-diazabicyclo (4,3,0) nonene-5}, DBA {6-dibutylamino-1,8-diazabicyclo (5,4,0) undecene-7 ｝ Or an organic acid salt thereof, such as tris-dimethylaminopropyl-hexahydro-S-triazine of an aminotriazine compound or an organic acid salt thereof, and dimethylcyclohexylamine (DMCH
A), dimethylbenzylamine (DMBA), dicyclohexylamine, organic acid salts, and the like, and mixtures thereof.
An amine catalyst having at least one alkyl group bonded to at least one alkyl group is preferred. These amine compounds are used as one kind or a mixture of two or more kinds, but are not limited thereto.

In a packing material for a hard disk, which is one of the uses of the polyurethane foam, a polyurethane foam which does not use an organic silicone foam stabilizer is desired. In order to produce such a foam, gelation is particularly required. It is essential to select a strong catalyst. This is because, in a curable composition having a slow gelation, bubbles easily merge and become coarse cells, so that it is difficult to obtain a foam having low air permeability with fine cells.

As a measure, an amine catalyst having a pKa of 9 or more, for example, a D having a cyclic amidine structure of about 12 or more is used.
BU {1,8-diazabicyclo (5,4,0) undecene-7}, DBN {1,5-diazabicyclo (4,3
0) -Nonene-5}, DBA {6-dimethylamino-1,8-diaza-dicyclo (5,4,0) undecene-7} or an organic acid salt thereof is selected to obtain a compound near room temperature. No catalytic activity, and heat of curing reaction of polyurethane foam or external heating
The acid is dissociated around 0 to 100 ° C., the catalyst activity is sharply increased, and there is a delay effect of terminating the curing reaction in a short time. Therefore, it is an ideal amine catalyst having a strong gelation reaction in the production of a polyurethane foam. In addition, these compounds exhibit an effect when added in a small amount, and are characterized in that the amount of migrating catalyst remaining in the product can be reduced. Furthermore, the aminotriazine compound tris-dimethylaminopropyl-hexahydro-S-triazine or an organic acid salt thereof is preferably used, but care must be taken to keep the compound in a small amount.

On the other hand, the highly gelling amine catalyst used in the present invention has an acid dissociation constant of 9 or more and a boiling point of 180 ° C.
The following tertiary amine compounds, dimethylcyclohexylamine (DMCHA-159 ° C), dimethylbenzylamine (DMBA-163 ° C), tris-dimethylaminopropyl-hexahydro-S-triazine (141 ° C)
And the like, and the fact that the gas generating component is reduced by selecting from these mixtures. That is, an amine catalyst having a strong gelation used in combination with a reactive amine catalyst has a boiling point of 1
By selecting a tertiary amine catalyst at a temperature of 80 ° C. or lower, the amine catalyst having a strong gelation easily vaporizes due to heat generation during the foam production and after-curing, so that the amount of the transferable amine catalyst remaining in the product is reduced. Therefore, it has been found that a polyurethane foam having an extremely low outgassing component can be obtained. Furthermore, the extremely low transferable amine catalyst remaining in the product reduces the amount of residual dissociation catalyst that accelerates decomposition when the product undergoes thermal degradation, thus exhibiting the characteristic of improving the heat resistance of the polyurethane foam. Is what you do.

On the other hand, the highly gelling amine catalyst used in the present invention is preferably a triazine tertiary amine catalyst having a boiling point of 150 ° C. or less, tris-dimethylaminopropyl-hexahydro-S-triazine or an organic acid salt thereof. Thus, it was found that a polyurethane foam having an extremely low gas generating component was obtained. Measurement of boiling point is J
The temperature at which the equilibrium reflux rate measured according to IS K 2233-1984 was maintained was determined.

In the polyurethane curable composition of the present invention, the mixing ratio of the reactive amine catalyst to the strongly gelling amine catalyst is 5: 5 to 4: 1 by weight, and the amount of the catalyst is 100 parts by weight of the polyol. It is preferable to add a small amount of 0.6 part or less, especially to 0.3 part or less. In the present invention, in particular, a reactive tertiary amine having one hydroxy group in the molecule; a combination of N, N-dimethylaminohexanol and an organic acid salt of DBU or tris-dimethylaminopropyl-hexahydro-S-triazine Is preferably used.

In the present invention, the catalyst (A) is a reactive amine catalyst having at least one hydroxy group in the molecule which reacts with the polyfunctional isocyanate, and the catalyst (B) has an acid dissociation constant pKa of 9 or more. The amine catalyst having strong gelation as described above, and a polyurethane foam obtained by reacting a composition containing a polyol component, a polyfunctional isocyanate and a foaming agent in the presence of catalysts (A) and (B) The body is
By performing the heat baking treatment, the transferable amine catalyst remaining in the product can be easily removed. The heat baking treatment of the present invention is desirably performed under conditions in which the polyurethane foam hardly undergoes thermal deterioration.
1 to 5 hours at 150 ° C, preferably 1 to 120 ° C or less
Although it is performed in 5 hours, vacuum heating baking is preferable because the processing can be performed efficiently at a relatively low temperature and in a short time. In particular, the highly gelling amine catalyst remaining as a transfer type in a product is characterized in that it can be easily removed by heating and baking for a relatively short time by specifying and using a compound having a boiling point of 180 ° C. or lower. Furthermore, they have found that it is particularly preferable to specify a compound having a boiling point of 150 ° C. or lower.

On the other hand, the polyurethane foam obtained from the curable composition of the polyurethane foam of the present invention has a low bleed-out component and a low outgassing component without using any organotin catalyst. Further, by performing a heating baking process, it is used as a soundproofing material and a packing material for a hard disk device.

The polyurethane foam according to the present invention is a polyurethane foam obtained by reacting a composition containing a polyol component and a polyfunctional isocyanate in the presence of a catalyst. Usually, a polyurethane foam having a relatively small thickness (50 mm or less) is continuously produced by applying a reaction material by a traverse method, a reverse coater method, or a die method. Furthermore, it is also manufactured by molding, small-quantity casting, and transfer molding. When the above-mentioned thin foam is continuously produced, if the initial foaming reaction / gelling reaction is insufficiently prepared, the application of the reaction raw materials becomes non-uniform, and the coating device is gelled and solidified, so that it is manufactured for a long time. In addition, there is a problem in that when the foamed product is rolled up and the product is cut into a single plate and the laminated product is stored, the products adhere to each other. Especially in the small volume casting method,
Since continuous casting is performed for a long time without washing the casting head, there is a problem that the casting head is gelled and solidified. In the present invention, a reactive amine catalyst and an amine catalyst having an acid dissociation constant pka of 9 or more and strong gelling are used in combination with a small amount of addition, and these improvements are achieved.

The polyurethane foam curable composition of the present invention requires a polyol component, a polyfunctional isocyanate, and other additives generally used in the production of polyurethane foam in the presence of the amine catalyst. There is no particular limitation as long as it is used accordingly. As polyether polyols, ethylene glycol, glycerin, polyhydric alcohols such as trimethylolpropane, ethylene oxide, propylene oxide, butylene oxide, addition polymerization products obtained by addition polymerization of alkylene oxides such as styrene oxide to these polyhydric alcohols, And mixtures thereof, but are not limited thereto. Polyester polyols include condensates obtained from the condensation reaction of polyhydric carboxylic acids such as adipic acid, phthalic acid, and succinic acid with polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, and trimethylolpropane. And mixtures thereof, but are not limited thereto. Examples of the polymer polyol include, in at least one of the polyols listed above, acrylonitrile in the presence of a radical initiator, a polymer obtained by polymerizing a vinyl monomer such as styrene, and the like, and a mixture thereof. It is not limited to this.

Other polyols include polyols containing melamine or ammonium polyphosphate dispersed therein and phosphorus-containing polyols, polylactone-based polyols obtained by ring-opening polymerization of lactones using polyhydric alcohols as initiators, polycarbonate polyols, polygen-based polyols and the like. And mixtures thereof, but are not limited thereto. Further, the polyol may be used as an OH group-terminated prepolymer reacted with a polyfunctional isocyanate described below, and the like.
It is not limited to these. In particular, for use as a sound absorbing material for automobiles and the like that require low gas generation and low water absorption (water repellency), the use of the following hydrophobic polyol is preferable because water resistance is imparted. The hydrophobic polyol is one that passes a polyol compatibility test described below. Specifically, as dimer acid-based polyols, esterified products of dimer acid and polyfunctional hydroxides such as ethylene glycol, diethylene glycol, trimethylolpropane, and glycerin, castor oil and castor oil modified products, polybutadiene-based polyols and hydrogenated products thereof Products, polyisoprene-based polyols and hydrogenated products thereof. These polyols include, but are not limited to, those used as OH-terminated prepolymers or NCO-terminated terminals which have been reacted with a polyfunctional isocyanate described below in advance.

The method for testing the compatibility of a polyol is that a sample of 2 g is placed in a glass test tube having a diameter of about 18 mm and a length of 180 mm.
Was weighed, and a solution in which isopropyl alcohol and distilled water were adjusted to a weight ratio of 75 to 25 in advance was dropped by a burette, and the solution gradually became turbid, and 0.5 m was passed through the test tube.
A sample having a solution addition amount of 2 g or less when the line m becomes invisible is judged to be acceptable. This test is performed at a liquid temperature of 25 ° C.

Examples of the polyfunctional isocyanate include aromatic polyisocyanates and aliphatic polyisocyanates containing two or more isocyanate groups in the molecule or modified products thereof, and specific examples thereof include toluene diisocyanate. Isocyanate (TDI), diphenylmethane isocyanate (MDI), isophorone diisocyanate (IPDA)
I), hexamethylene diisocyanate (HDI), tetramethylxylylene diisocyanate (TMXDI)
And mixtures thereof. Or an NCO group-terminated prepolymer reacted with the polyol,
And mixtures thereof, but are not limited thereto.

Examples of the foam stabilizer include an organic silicone foam stabilizer, a surfactant and the like, and a mixture thereof. In the former, it is preferable not to use it depending on the use. It is preferable to use a silicone foam stabilizer having an active group such as a hydroxy group, a mercapto group, an amino group, an epoxy group, and a carboxyl group that reacts with the isocyanate, because the silicone foam becomes non-migratory. The latter includes, but is not limited to, diethylaminooleate, sorbitan monostearate, glycerin monooleate, vinylpyrrolidone, fluorine, organic compounds, and the like, and mixtures thereof. In particular, when used as a packing material for a hard disk drive that requires low gas generation, the foam stabilizer is used in the smallest possible addition amount, but is preferably not added.

Examples of the foaming agent include water; inert gas such as nitrogen gas, carbon dioxide gas, and air at normal pressure; halogenated alkanes such as monofluorotrichloromethane and dichloride methane; butane and pentane; Examples include, but are not limited to, low-boiling alkanes; azobisisobutylnitrile that generates decomposed nitrogen gas, and the like, and mixtures thereof. As other additives, a crosslinking agent, a colorant, a resin modifier, a flame retardant, an ultraviolet absorber, a durability improver, and the like can be optionally used as needed. The curable composition of the polyurethane foam of the present invention uses the above-mentioned various raw materials to form a polyurethane foam, and the production method thereof is conventionally known (1) prepolymer method, (2) ) It can be produced by any one of the one-shot method and the (3) partial prepolymer method. These products include slabs, molds or double-sided skins, as well as small cast molds.

[0029]

Examples and Comparative Examples Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Parts and percentages are by weight. In addition, the curable composition of the polyurethane foam, conventionally known foaming agents, crosslinking agents, coloring agents, foam stabilizers, resin modifiers, flame retardants, ultraviolet absorbers, additives such as durability improvers, It can be added within a range that does not impair the purpose of the present invention. Next, the production of the foam obtained from the curable composition of the polyurethane foam in Examples and Comparative Examples is carried out by mixing and stirring a compound comprising a polyol, an isocyanate, a catalyst, and other additives. At room temperature
A method of obtaining a foam by free foaming with a liter poly beaker, or after evenly applying the release treatment surface of the process paper subjected to the release treatment using an application bar, covering the process paper so that the release treatment surface also comes to the upper surface, Heating oven (70 ℃ × 3min + 1
(20 ° C. × 4 minutes) to obtain a sheet-like foam by foaming and curing.

The catalysts used are as follows: Catalyst A: dimethylethanolamine (DMEA), reactive amine catalyst having a terminal hydroxy group, pKa 8.5 Catalyst B: dimethylaminoethoxyethoxyethanol (Kaorizer No. 23; manufactured by Kao Corporation), having a terminal hydroxy group Reactive amine catalyst, pKa 8.6 Catalyst C; dimethylaminohexanol (Kaorizer No. 25; manufactured by Kao Corporation), reactive amine catalyst having a terminal hydroxy group, pKa10 Catalyst D; Tris-dimethylpropyl-hexahydro-S
-Triazine, boiling point 141 ° C (Kaorizer No. 1
4; Kao Corp.), pKa 9.3 Catalyst E; mixture of bis (dimethylaminoethyl) ether / dipropylene glycol (3 to 7 weight ratio), boiling point 1
70 ° C. (Kaorizer No. 12; manufactured by Kao Corporation)
pKa8.8 Catalyst F; a mixture of triethylenediamine / dipropylene glycol (1: 2 by weight), boiling point 174 ° C, (33-
LV; manufactured by Sankyo Air Products Co., Ltd.), pKa8.7 Catalyst G; DBU ｛1,8-diazabicyclo (5,4,
0) -undecene-7% octylate, boiling point 240 ° C
(SA.102; manufactured by Sun Apro Co., Ltd.), pKa11.
5 Catalyst H; DBN @ 1,5-diazabicyclo (4,3,
0) -Nonene-5% octylate, boiling point 200 ° C (U
-Cat1102; manufactured by Sun Apro Co., Ltd.), p
Ka11.7 Catalyst I; dimethylcyclohexylamine (DMCH
A), boiling point 160 ° C. (Poly Cat-8; manufactured by San Apro Co., Ltd.), pKa 10.5

Examples 1 to 6 and Comparative Examples 1 to 3 100 parts of polyol having an OH value of 40 by adding propylene oxide and ethylene oxide to glycerin / ethylene glycol (Actocol GS-92; manufactured by Takeda Pharmaceutical Co., Ltd.) 2.5 parts of purified water as a foaming agent, 3 parts of a carbon black colorant (TUR-0235; manufactured by Toyo Ink Mfg. Co., Ltd.), a predetermined amount of an amine catalyst, a silicone foam stabilizer having a terminal OH group. 1 part, terminal NCO prepolymer NCO2 using diphenylmethane diisocyanate
3% (Takenate SI-45P; Takeda Pharmaceutical Co., Ltd.)
Made) and crude diphenylmethane diisocyanate NCO3
1% (Takenate ISO-01P; Takeda Pharmaceutical Co., Ltd.)
8/2 weight blend product of ICO in an NCO / OH equivalent ratio of I
The blend having ndex103 was mixed and stirred at a raw material temperature of 25 ° C., and a free foaming method was performed to produce a polyurethane foam having an expansion ratio of about 20 to 25 times. In addition, regarding the curing reaction of polyurethane foam, the initial evaluation of the foaming reaction as a cream time (cream) and the gelation reaction as a tack free time (tack free) are performed as a curing reaction evaluation. It is intended to easily evaluate the adhesion (blocking) of products generated during uniform application and curing of coating equipment, winding of roll-shaped products or lamination and storage of single-plate cut products. The term “tack” means the time from the end of contact with the surface skin of the foam after the completion of the curing reaction and the elimination of stringing and tack. In addition, a test piece was collected from the obtained foam, and the density (g) was measured in accordance with JIS K6401.
/ Cm ³ ). For quantitative analysis of gas generation components, see J
Gas chromatograph mass spectrometry (GC
-MS). The GC-MC analyzer uses QP-5000 manufactured by Shimadzu Corporation, the head space sampler uses JHS-100 / AQ-200 manufactured by Nippon Kagaku Kogyo, and the column uses DB-1 (0.25 mm × 30 m, 0.25 μm). The analysis operation is about 3 mm in width and height x 2 c in length.
Approximately 0.4 g of a sample cut to a length of 150 m or less was taken out into a test tube, and heated at a rate of 10 ° C./m.
Gas analysis was performed by the purge and trap method in, and quantification was performed based on the peak area of the amine component. For quantification, a trimer of dimethyl silicone having a known concentration is used as a standard solution. The results are shown in Tables 1 and 2.

[0032]

[Table 1]

[0033]

[Table 2]

In Examples 1 to 4, the combination of a reactive amine catalyst having a hydroxy group and an amine catalyst having an acid dissociation constant pka of 9 or more and having a high gelation was used. It can be seen that the composition is a curable composition having a low outgassing component and a well-balanced foaming reaction / gelation reaction. Comparative Example 1 uses only a reactive amine catalyst having a hydroxy group. If the addition amount is small, the gelation reaction is insufficient, and if the addition amount is increased by this improvement, the initial foaming reaction is too fast. . In Comparative Examples 2 and 3, the combined use of a reactive amine catalyst and an amine catalyst having an acid dissociation constant pka of 9 or less was used, but the gelling reaction was insufficient, although the initial foaming reaction was fast. In each case, the gas generating components are large, and the balance between the initial foaming reaction and the gelling reaction is poor, so that the present invention cannot be satisfied.

Example 5 is a modification of the catalyst system of Example 3 to a hydrophobic polyol having an OH value of 70 obtained by addition polymerization of dimer acid and short-chain diol and triol. A sample was collected from the obtained foam, and the sample was immersed under a water depth of 10 CM for 24 hours in a state where the sample was compressed by 50%, and was taken out.
The volume of water absorbed by the sample was measured, and the water absorption (v
ol%). As a result, in contrast to the water absorption of 10% of Example 3, the water absorption of Example 5 was as low as 4%, which was good. It was found that the foam had improved water resistance, and the gas generation and water absorption ( Water repellency)
It is suitable as a sound-absorbing material for automobiles and the like that require a.

Examples 6-7 and Comparative Examples 4-5 In Example 6, the same amine catalyst as in Example 3 was used. In Example 7, the reactive amine catalyst C of Example 6 and the amine catalyst having strong gelation were used. G was used in combination, and otherwise the same composition as the composition of the above example was mixed and stirred at a raw material temperature of 25 ° C., and foaming was carried out by a method of obtaining a sheet-like foam. A 25 times polyurethane foam was made. As for the curing reaction of the polyurethane foam, the initial foaming reaction is evaluated in the coating state, and the gelling reaction is evaluated for the blocking property, so that the problems in the production of the foam can be easily evaluated in the same manner as in the slab foaming method. The reaction material mixed and agitated using a coating bar is used to evaluate the ease of application to the release-treated surface of the process paper and the uniformity of the thickness of the obtained foam. Is obtained by dividing the foam immediately after the completion of the curing reaction, laminating the foam, and then peeling it after 4 hours or more to evaluate the degree of peeling.

Evaluation criteria for coating state Evaluation criteria for blocking properties ；: Foam with uniform coating and uniform thickness ；: Easily peeled and no skin damage However, there was no skin damage. ×: Foaming reaction could not be applied quickly. ×; peeling was heavy and skin damage occurred. These results are shown in Table 3.

[0038]

[Table 3]

In Example 7, the combination of the reactive amine catalyst of Example 6 and an amine catalyst having a strong gelling effect with the octylate of DBU having a cyclic amidine structure was used to reduce the initial foaming amount with a small amount of catalyst added. It can be seen that the composition is a curable composition having a low outgassing component and a good balance between the gelation reaction and the gelation reaction. Among them, those using an aminotriazine-based compound can suppress the amount of outgassing components to a low level. Comparative Examples 4 and 5 show a case where bis-dimethylaminoethyl ether or triethylenediamine was used as an amine catalyst having an acid dissociation constant pka of 9 or less in a combined system of a reactive amine catalyst and an amine catalyst having strong gelation. However, although the initial foaming reaction is fast, the gelling reaction is insufficient. In each case, the gas generating components are so large that the present invention cannot be satisfied.

Examples 8 to 12 and Comparative Examples 6 to 7 30 parts of a polyol having an OH value of 56 with an adduct of propylene oxide and ethylene oxide to glycerin, 70 parts of a polyol having an OH value of 56 with an adduct of glycerin and propylene oxide, 4 parts of a trifunctional crosslinking agent having a value of 910,
1,4 butanediol 4 parts, non-silicone foam stabilizer 0.1
Parts, 0.2 parts of purified water as a foaming agent, inorganic filler 15
Parts, 3 parts of a carbon black colorant, a predetermined amount of an amine catalyst, NCO 29% (Isonate-143L; diphenylmethane diisocyanate modified with carbodiimide)
MDI Kasei Co., Ltd.) at an NCO / OH ratio of Index
The mixture prepared as 105 was mixed and stirred at a raw material temperature of 25 ° C. to obtain a sheet-like foam, and a sheet-like polyurethane foam having an expansion ratio of about 3 was produced. As for the curing reaction of the polyurethane foam, the initial foaming reaction was evaluated in the applied state, and the gelation reaction was evaluated for restorability in the same manner as in the above-described example, and the problems in producing the foam were easily evaluated. I do. With respect to the resilience, the foam immediately after the completion of the curing reaction was strongly pressed with an aluminum jig having a flat tip of 10 mm in diameter for 5 seconds, and the resilience after 5 seconds from opening was determined by the following formula, and evaluated according to the evaluation criteria.

[0041]

Evaluation criteria of restorability 性 の: Restoration rate of 80% or more Δ: Restoration rate of 50 to 80% ×: Restoration rate of 50% or less

The obtained foam was evaluated for air sealing performance required as a packing material by air leak performance. The air leaking property is obtained by collecting a ring-shaped test piece (thickness = outside diameter 36 mmφ = inside diameter 32 mmφ) from a foam, and FIG.
The air leak property is measured by using the test device of the above. Specifically, after compressing a test piece by 50% with an acrylic plate, a predetermined pressure (mmAq) is applied to the inner diameter part of the test piece, and the amount of air leaked to the outer diameter part of the test piece is measured by a flow meter (cc / min). ) To read.

[0044] The air leaking property is as follows.
The air leak pressure is increased to 5000 mmAq for each q, and when a leak exceeding 10 cc / min occurs,
Evaluation was performed according to the following evaluation criteria. Evaluation criteria of air leak ◎: 5000 mmAq or more ○; 3000 mmAq △; 2000 mmAq ×; 1000 mmAq or less

Further, the obtained foam was subjected to quantitative analysis of gas-evolving components by the analysis method described later for the presence or absence of a heat baking treatment. The heating and baking treatment performed in the present invention is performed by taking a sample of about 10 cm square in thickness from the obtained foam and suspending it in a hot air circulating oven adjusted to 120 ° C. for 4 hours in a suspended state. The present invention is not limited to this condition, and has such features that if the vacuum heating baking treatment is performed, the treatment temperature can be set low or the treatment effect can be exhibited in a short time. Quantitative analysis of gas generation components is based on JIS K
Gas Chromatography Mass Spectrometry of GC 0123 (GC-MS)
Performed according to. The GC-MC analyzer is a Q made by Shimadzu Corporation.
P-5000, head space sampler is JHS-100 / AQ-200 manufactured by Nippon Kagaku Kogyo, column is DB-
1 (0.25 mm × 30 m, 0.25 μm), and as an analysis operation, about 0.4 g of a sample cut into a width and a height of about 3 mm × a length of 2 cm or less was collected in a test tube, and the heat injection conditions were as follows. Gas analysis was performed by a purge and trap method at 150 ° C. for 10 minutes and at a heating rate of 10 ° C./min, and quantification was performed based on the peak area of the amine component. For quantification, a trimer of dimethyl silicone having a known concentration is used as a standard solution. Table 4 shows these results.
Shown in

[Table 4]

In Examples 8 and 9, a reactive amine catalyst having 2 or 6 carbon atoms and an amine catalyst having strong gelling were used in combination. A gelation / gelation reaction has been prepared. Furthermore, as shown by the results of quantitative gas generation analysis, it was confirmed that the composition was a curable composition of a polyurethane foam having a low gas generating component, which satisfies the present invention. In particular, by performing the heating baking treatment, the gas generating component is significantly reduced. Example 9
Nos. To 12 are those in which a reactive amine catalyst having 6 carbon atoms and an amine catalyst having a different boiling point and strong gelation are used in combination, and the initial foaming reaction / gelation reaction is balanced. Further, as shown by the results of quantitative gas generation analysis, by selecting an amine catalyst having a boiling point of 180 ° C. or lower, particularly preferably 150 ° C. or lower, it is possible to suppress gas generating components to a low level. By further performing the heating baking process,
Although the gas generation component is significantly reduced, this gas generation amount is 20
It is particularly preferable to select an amine catalyst having a boiling point of 150 ° C. or less as follows.

In Comparative Examples 6 and 7, the reactive amine catalyst of Examples 9 to 12 was changed to an amine catalyst having no reactive group. Inferior air leak properties and extremely large outgassing components do not satisfy the present invention. As described above, in the present invention, without using any organotin-based catalyst, it is possible to obtain a low-permeable sheet-like foam with a low gas generating component, so that it is suitable as a soundproofing material and a packing material for a hard disk drive. is there.

[0048]

The effects of the present invention are listed below. * When producing a relatively thin sheet-like polyurethane foam, the initial foaming reaction and the gelling reaction can be easily adjusted with a small amount of catalyst, so that a good product with excellent production stability and no blocking can be obtained. It can be manufactured. * Since the polyurethane foam of the present invention has a low outgassing component, contact failure and erroneous operation can be suppressed even when used for a soundproofing material or a packing material for electronic devices. Further, even when used as a soundproofing material and a packing material for an automobile interior, the occurrence of fogging that foggs the glass can be suppressed. * Since the polyurethane foam of the present invention has an extremely small amount of the amine catalyst remaining in a state having catalytic activity, durability such as heat resistance is improved. * The polyurethane foam of the present invention can easily remove the transferable amine catalyst remaining in the product by performing the heat baking treatment. * If a tertiary amine catalyst with a boiling point of 180 ° C and strong gelation is selected, a small amount of residual polyurethane in the product is subjected to a relatively short heating baking process, etc., to further reduce the amount of gas generating components. A foam can be manufactured. * Since it is a polyurethane foam with a reduced outgassing component consisting of an amine catalyst which does not use a silicone foam stabilizer and does not use any organotin catalyst, it is especially used for soundproofing materials and packing materials for hard disk drives. It is suitable.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an air leak test apparatus.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koichi Kusakawa 1170 Ako, Komagane-shi, Nagano F-term (reference) 4H017 AA04 AA31 AC01 AC13 AD01 AE05 4J034 BA02 CA04 CA05 CA24 DA01 DA05 DB04 DF01 DF02 DF03 DF11 HA01 HA07 HC12 HC17 HC52 HC61 HC64 HC67 HC71 HC73 KA01 KB04 KB05 KD07 KD11 KD12 KD21 NA02 NA03 QC01 RA14 RA15

Claims (6)

[Claims] 1. A polyurethane foam obtained by reacting a composition containing a polyol component and a polyfunctional isocyanate in the presence of a catalyst, wherein a hydroxy group reacting with the polyfunctional isocyanate as the catalyst (A) Alternatively, a reactive amine catalyst having at least one mercapto group in a molecule and an acid dissociation constant pKa of 9 as catalyst (B)
A curable composition of a polyurethane foam having a low gas generating component, characterized in that it is used in combination with an amine catalyst having a strong gelation. 2. The reactive amine catalyst as the catalyst (A),
A tertiary amine compound represented by the following general formula, wherein a carbon-carbon bond is bonded to a nitrogen atom and a hydroxy group by 2 to 10 carbon atoms.
The curable composition for a polyurethane foam according to claim 1, wherein the curable composition is a compound having at least one compound. Embedded image (Wherein, R is an alkyl group having 1 to 6 carbon atoms, and n represents an integer of 2 to 10) 3. The polyurethane foam according to claim 1, wherein the highly gelling amine catalyst as the catalyst (B) is a tertiary amine compound having a boiling point of 180 ° C. or lower. Curable composition. 4. The curable composition of a polyurethane foam having a low gas generating component according to claim 1, wherein the amine catalyst having strong gelling as the catalyst (B) is a triazine-based tertiary amine catalyst. object. 5. The catalyst (A) is a reactive amine catalyst having at least one hydroxy group in a molecule that reacts with a polyfunctional isocyanate, and the catalyst (B) is an acid dissociation constant p.
A highly gelling amine catalyst having a Ka of 9 or more, which is obtained by reacting a composition containing a polyol component, a polyfunctional isocyanate, and a blowing agent in the presence of catalysts (A) and (B). A method for producing a polyurethane foam having a low gas generating component, wherein the polyurethane foam is heated and baked. 6. A soundproofing material or a packing material for a hard disk drive, wherein the polyurethane foam having a low gas generating component according to claim 1 is used.