JP2002265556A - Rigid polyurethane foam and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rigid polyurethane foam having excellent heat insulating properties, dimensional stability, and compression strength, of which raw material cyclic urea compounds can be easily produced by decomposition and regeneration from rigid polyurethane foams, and the characteristics of the obtained rigid polyurethane foam are equal to or better than those of the known rigid polyurethane foams, offering an effective recycling process of raw materials relating to rigid polyurethane foam. SOLUTION: This rigid polyurethane foam is characterized in containing a constituent unit represented by formula [1] (wherein m and n are each an integer of 1-10; and R<1> and R<2> are each hydrogen atom or an alkyl group) in an amount of 0.03-10 mass%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a rigid polyurethane foam and a method for producing the same, and more particularly, to a rigid polyurethane foam comprising a specific polyol. Further, the present invention relates to a rigid polyurethane foam obtained by using a polyol obtained as a raw material polyol from a decomposition and regeneration treatment step of a rigid polyurethane foam used for a building material, a structural material, a heat insulating material, and the like.

[0002]

Technical background of the invention Rigid polyurethane foam is excellent in heat insulation performance, dimensional stability, etc., and a polyol and an organic polyisocyanate are used as a foaming agent, if necessary, a catalyst,
It can be easily manufactured by mixing with a foam stabilizer and other auxiliaries, and has excellent workability, so it can be used as a heat insulating material or a heat insulating structural material for refrigerators, freezers, building materials, ships or vehicles, etc. Widely used.

On the other hand, in recent years, recycling of polymers has become a major issue as part of the response to global environmental problems. Regarding the polyurethane resin, various techniques for chemically decomposing the rigid polyurethane foam to recover the polyol and reusing (recycling) the polyol as a raw material of a new polyurethane foam have been developed.

Against this background, the inventors of the present invention have proposed a method for recycling a rigid polyurethane foam, in which a rigid polyurethane foam is decomposed in a monoalkanolamine, and an active hydrogen compound contained in a decomposed solution is obtained. 2 carbon atoms without catalyst or with amine catalyst
It has been found that a polyether polyol can be easily obtained by adding about 4 to about 4 alkylene oxides (JP-A-6-192362).

In the method for decomposing and regenerating a rigid polyurethane foam by the present applicant, for example, when 1-amino-2-ethanol is used as a monoalkanolamine, a rigid polyurethane foam is used as a main component in a decomposition product. Of N, N′-bis (hydroxyethyl) urea (hereinafter sometimes referred to as “BHEU”) derived from a polyol derived from a polyol which is a raw material of the compound, an amine derived from an isocyanate, and 1-amino-2-ethanol. Is a cyclic urea compound derived from 1-amino-2-ethanol, N-hydroxyethylimidazolidone (hereinafter referred to as “HEIM”), as a by-product.
A trace amount (BHEU is the main product and HEIM is produced in a trace amount. BHEU
→ The reaction is completed before HEIM + H ₂ O). The method for decomposing and regenerating a rigid polyurethane foam by the present applicants is also suitable for decomposing a large amount of a rigid polyurethane foam, and as a result, the cyclic urea-based compound can be produced in a large amount as a by-product. Effective utilization of cyclic urea compounds has been a major issue. In Japanese Patent Application Laid-Open No. 6-192362 by the applicants of the present application, it is described that the decomposition regeneration method is an effective method for recycling polyol which is a main decomposition product of a rigid polyurethane foam. However, there is no specific description or suggestion about an effective method of recycling cyclic urea-based compounds such as HEIM as a by-product, and the performance of a rigid polyurethane foam using the same.

[0006]

The object of the present invention is to use a polyol having a skeleton derived from a cyclic urea compound, which can also be obtained as a raw material for regenerating a rigid polyurethane foam, and has excellent heat insulation performance, dimensional stability, compressive strength, thermal conductivity, moldability, and the like. The purpose is to obtain a rigid polyurethane foam.

[0007]

SUMMARY OF THE INVENTION The present inventors have conducted intensive studies to solve the above-mentioned problems, and when a polyol containing a specific amount of an alcohol derived from a cyclic urea compound is used, the obtained rigid polyurethane foam has heat insulating performance and dimensional stability. , Found to be excellent in compressive strength, thermal conductivity, moldability, etc.
The present invention has been completed. Further, since the cyclic urea-based compound is easily and easily available in large quantities as a raw material from a wide range of rigid polyurethane foams, the rigid polyurethane foam according to the present invention is used for efficient recycling of the rigid polyurethane foam. I found it to be a technique. That is, the outline of the present invention is as follows.

The rigid polyurethane foam according to the present invention has the following general formula [I]

[0009]

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[In the formula [I], m and n are each independently 1
And R ¹ and R ² are each independently a hydrogen atom or an alkyl group].
It is characterized in that it is contained in an amount of 0.03% by mass or more and 10% by mass or less. In the structural unit represented by the formula [I], it is preferable that n and m in the formula [I] are each independently an integer of 1 to 3. The heat transfer coefficient of the rigid polyurethane foam is 16.8 mW / mK or more and 25.5 mW.
/ MK or less. The core density of the rigid polyurethane foam 2 kg / m ³ or more 100 kg / m ³
It is preferably within the following range.

The method for producing a rigid polyurethane foam according to the present invention is represented by the following general formula [I]:

[0012]

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[In the formula [I], m and n are each independently 1
And R ¹ and R ² are each independently a hydrogen atom or an alkyl group]. The polyol includes a structural unit derived from the compound represented by the general formula [I] in the polyol (that is, in the skeleton).
In an amount of 0.05% by mass or more and 20% by mass or less.

[0014] A heat insulating material according to the present invention is characterized by being made of the rigid polyurethane foam.

[0015]

DETAILED DESCRIPTION OF THE INVENTION The rigid polyurethane foam according to the present invention is a rigid polyurethane foam containing a skeleton derived from a cyclic urea compound such as an N-hydroxyethylimidazolidone compound as a polyol component. [Polyol] (Cyclic urea compound) The rigid polyurethane foam according to the present invention has the following general formula [I]

[0016]

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And a structural unit derived from a cyclic urea compound represented by the formula: In the above formula [I], m and n are each independently an integer of 1 to 10. Of these, m, n
Is preferably independently an integer of 1 to 3,
More preferably, m and n are the same integer, m (or n) is an integer of 1 to 3, and
It is preferable that R ¹ and R ² are the same and both are a hydrogen atom or a methyl group. Of these, R ¹ ,
Preferably, both R ² are hydrogen atoms.

R ¹ is a hydrogen atom or an alkyl group, wherein the alkyl group is a methyl group, an ethyl group, an n-, iso-propyl group, a sec-, tert
-, An alkyl group having 1 to 4 carbon atoms such as an iso-butyl group is preferable. When R ¹ is an alkyl group, the total (m + p) of the carbon number p of the alkyl group and the above m is preferably an integer of 2 to 10.

R ² is a hydrogen atom or an alkyl group, wherein the alkyl group is a methyl group, an ethyl group, n
-, Iso-propyl group, sec-, tert-, is
An alkyl group having 1 to 4 carbon atoms such as an o-butyl group is preferred. When R ² is an alkyl group, the total (n + p) of the number of carbon atoms q of the alkyl group and the above n is preferably an integer of 2 to 10.

The structural unit derived from the cyclic urea-based compound having such a skeleton is contained in the rigid polyurethane foam according to the present invention in an amount of 0.03% by mass or more and 10% by mass or less, preferably 0.05% by mass. It is desirable that the rigid polyurethane foam is contained in the rigid polyurethane foam in an amount of from 7% by mass to 7% by mass, particularly preferably from 0.1% by mass to 5% by mass. When the structural unit derived from the cyclic urea-based compound is contained in such a ratio, a rigid polyurethane foam having excellent moldability, heat insulation properties, and strength can be obtained.

The cyclic urea compound capable of deriving such a structural unit derived from the cyclic urea compound is represented by the following general formula [II].

[0022]

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In the formula [II], m and n are the same as in the above formula [I], each independently being an integer of 1 to 10, and R ¹ and R ² are also the same as those in the above formula [I]. It is the same, and is a hydrogen atom or an alkyl group. Further, similarly to the above formula [I], when R ¹ and R ² are alkyl groups, the number of carbon atoms p and q of the alkyl group and the sum of the above m and n (m + p), (n + q)
Is preferably an integer of 2 to 10, respectively. Examples of such a cyclic urea-based compound include the following.

[0024]

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Of these,

[0026]

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Is particularly preferably used. Such a cyclic urea-based compound can be obtained as a decomposition by-product by decomposing a rigid polyurethane foam in a monoalkanolamine according to the method described in JP-A-6-192362. . Specifically, for example, 1-amino-2-ethanol, 1
Monoalkanolamines such as -amino-2-propanol and 1-amino-3-propanol are used in an amount equivalent to twice that of the isocyanate used in producing the rigid polyurethane foam to be decomposed. By reacting at temperature for several hours,
The cyclic urea-based compound can be obtained together with a polyol derived from a polyol used as a raw material of the rigid polyurethane foam as a main component, an amine derived from isocyanate, and a chain urea derived from a monoalkanolamine. Further, by selecting various monoalkanolamines to be used, a cyclic urea-based compound having a desired structure can be obtained.

As described in JP-A-6-192362, the produced cyclic urea-based compound has
By adding an alkylene oxide without a catalyst or in the presence of an amine catalyst, a polyol derived from a cyclic urea-based compound having a desired viscosity and hydroxyl value can also be obtained. The compound represented by the general formula (II) is preferably used as a polyether polyol obtainable by reacting with an alkylene oxide. The general formula (II)
Examples of the alkylene oxide used to produce the polyether polyol by reacting with ethylene oxide include ethylene oxide, propylene oxide, butylene oxide, and styrene oxide. Of these, ethylene oxide and propylene oxide are preferable.

These can be used alone or in combination of two or more. In the polyol obtained by adding such an alkylene oxide to the cyclic urea-based compound, a structural unit derived from the cyclic urea-based compound is preferably 0.05% by mass or more and 20% by mass or less,
More preferably, it is contained in an amount of from 0.2% by mass to 15% by mass, particularly preferably from 0.2% by mass to 10% by mass.

The polyol containing such a cyclic urea compound as a constituent unit has a hydroxyl value of 200 to 600.
mgKOH / g, preferably 300-500 mgKOH
/ G is preferred. Hydroxyl value is 600mgKOH /
If it exceeds g, the viscosity tends to be high and a problem may occur in practical use. If the hydroxyl value is less than 200 mgKOH / g, the strength of the obtained rigid polyurethane foam may easily decrease. . (Other Polyol) As the raw material of the rigid polyurethane foam according to the present invention, the polyol may be used in combination with another polyol in addition to the polyol having the structural unit derived from the cyclic urea-based compound. As such other polyol, known polyols such as polyether polyol and polyester polyol can be used,
There is no particular limitation.

Specific examples of such polyether polyols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, and sucrose. Ethylene oxide, propylene oxide, butylene to a polyhydric alcohol such as tolamine, an aromatic amine such as tolylenediamine, or an aliphatic amine such as ethylenediamine or triethanolamine, alone or as a mixture of two or more. Hydroxyl value obtained by subjecting an alkylene oxide such as oxide and styrene oxide to addition polymerization, and a hydroxyl value of 200 to 800
mg KOH / g of polyether polyol and the like. Among them, a polyol having a hydroxyl value of 400 mgKOH / g obtained by adding propylene oxide to a mixture of o-toluenediamine and triethanolamine,
A polyol having a hydroxyl value of 450 mg KOH / g obtained by adding propylene oxide to a sucrose / glycerin mixture, a polyol having a hydroxyl value obtained by adding propylene oxide to glycerin having a hydroxyl value of 450 mg KOH / g, or a mixture thereof can be preferably used.

In the present invention, 2,5 (or 6) -bis (aminomethyl) -bicyclo [2,2,1]
A polyether polyol having heptane (hereinafter sometimes referred to as “NBDA”) as an initiator may be used as another polyol. This polyether polyol has a hydroxyl value of 200 to 600 mgKOH / obtained by adding an alkylene oxide using NBDA as an initiator.
g, preferably 300 to 500 mg KOH / g. When the hydroxyl value exceeds 600 mgKOH / g, the viscosity tends to be high, and there is a possibility that a problem may occur in practical use. When the hydroxyl value is less than 200 mgKOH / g,
There is also a possibility that the strength of the obtained rigid polyurethane foam tends to decrease.

In the present invention, polyester polyols can also be preferably used. Such a polyester polyol has a hydroxyl value of 200 to 600.
Those which are mgKOH / g are preferred. Such polyester polyols include, for example, dicarboxylic acids such as phthalic acid or diesters thereof, and ethylene glycol, diethylene glycol (DEG), triethylene glycol (TEG), propylene glycol (PE
G) a polyol such as dipropylene glycol (DPG), 1,4-butanediol, 1,2-butanediol, and glycerin with a polyol in the presence or absence of a catalyst such as titanium alkoxide to obtain a hydroxyl value by condensation. 450
Aromatic polyester polyols obtained by reducing the amount to about mgKOH / g are exemplified. Further, a carboxylic acid formed by adding a polyvalent active hydrogen compound having two or more active hydrogens capable of reacting with isocyanate to a cyclic acid anhydride such as phthalic anhydride is added with dimethyl until the hydroxyl value becomes 450 mgKOH / g or less. A polyester polyol produced by adding an alkylene oxide using a tertiary amine containing a long-chain hydrocarbon such as palmitylamine as a catalyst is also included.

When such another polyol is used in combination, the lower limit of the content of the polyol having a component derived from the cyclic urea compound skeleton in the polyol is 5%.
The amount is preferably 0% by mass or more, more preferably 70% by mass or more, particularly preferably 80% by mass or more and 99% by mass or less. In addition, the hydroxyl value of the polyol according to the present invention relating to the other polyol used in combination with the cyclic urea-based compound, if necessary, is 200 to 600 mgKOH / g, preferably 300, in weighted average.
Those having a concentration of ５００500 mg KOH / g are preferred. By setting the hydroxyl value to 600 mgKOH / g or less, operability is further improved, which is preferable. The hydroxyl value is 200 mgKOH /
By setting it to g or more, the strength and long-term durability of the rigid polyurethane foam are improved, which is preferable. [Organic polyisocyanate] The organic polyisocyanate used in the rigid polyurethane foam according to the present invention includes aromatic polyurethane, aliphatic aliphatic, and alicyclic rigid polyurethane foams having two or more isocyanate groups in one molecule. Known products used for production can be used.

Examples of such organic polyisocyanates include 2,4-tolylene diisocyanate,
2,6-tolylene diisocyanate, an isomer mixture of these organic polyisocyanates ((2,4-tolylene diisocyanate) / (2,6-tolylene diisocyanate)
0/20 weight ratio (TDI-80 / 20), 65/35 weight ratio (TDI-65 / 35)), crude tolylene diisocyanate containing polyfunctional tar (multifunctional tar is used to produce isocyanate) A mixture of tar-like substances containing two or more isocyanate groups in the molecule. The same applies hereinafter.), 4,4′-diphenylmethane diisocyanate (4,4′-MDI), 2,4 '-Diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, any mixture of isomers of diphenylmethane diisocyanate, crude diphenylmethane diisocyanate (polymeric MDI or poly-MDI) containing trifunctional or higher polyfunctional tar, toluylene diisocyanate , Xylylene diisocyanate, hexamethylene diisocyanate, isophor Down diisocyanate, naphthalene diisocyanate, paraphenylene diisocyanate, norbornene diisocyanate, and carbodiimide modified products of these organic polyisocyanates, biuret modified products, or an isocyanate prepolymer reacted with an active hydride such as these polyols.

Of these, in the present invention, poly-M
DI, 4,4'-MDI and the like can be preferably used.
A mixture of MDI isomers can be preferably used. Such organic polyisocyanates can be used in a mixture at any ratio. The amount of the polyisocyanate to be used for the polyol is almost the same as in the case of the ordinary rigid polyurethane foam, and the NCO / H (active hydrogen) (molar ratio) is preferably 0.3 to 3.0, and more preferably 0.1 to 3.0.
It is desirable to be 5 to 2.0, particularly preferably 0.7 to 1.5. [Blowing agent] The blowing agent according to the present invention is not particularly limited as long as it is a foaming agent that can be used for foaming a rigid polyurethane foam, but a foaming agent other than chlorofluorocarbon is preferable from the viewpoint of addressing global environmental problems. As the foaming agent, a hydrocarbon compound can be used, and a hydrocarbon having 3 to 8 carbon atoms can be preferably used. In particular,
Examples include propane, n-butane, isobutane, n-pentane, isopentane, neopentane, n-hexane, isohexane, n-heptane, isoheptane, cyclopentane, cyclohexane, cycloheptane, and the like.

These can be used alone or in combination of two or more. Of these, cyclopentane,
Isopentane can be preferably used, and cyclopentane is particularly preferable. In the present invention, water can be used in combination as a foaming agent. As the water, ion-exchanged water and distilled water are usually used, but in some cases, industrial water can be used as it is.

These foaming agents can be used alone or in combination of two or more. The amount of such a foaming agent is 1 to 100 parts by mass of all polyol components.
50 parts by mass can be used, and more preferably 2 to 40 parts
It is desirable that the amount be 5 parts by mass, particularly preferably 5 to 30 parts by mass. [Urethanation catalyst] Examples of the urethanization catalyst used in the present invention include amines, quaternary ammonium compounds, alkali metal salts, tin compounds, phenolate compounds, metal halides, metal complex compounds, etc. which are usually used for urethane foaming. Any catalyst can be used.

Among such catalysts, the amines include, specifically, trimethylaminoethylpiperazine,
Triethylamine, tripropylamine, N-methylmorpholine, N-ethylmorpholine, triethylenediamine, N, N, N ', N'-tetramethylhexamethylenediamine, N, N, N', N ', N'- Pentamethyldiethylenetriamine, dimethylcyclohexylamine, diazobicycloundecene, 1,3,5-tris (dimethylaminopropyl) hexahydro-s-triazine and the like can be mentioned.

Examples of the aziridine include 2-ethylaziridine. Examples of the quaternary ammonium compound include carboxylic acid salts of tertiary amines. As alkali metal salts, potassium octylate,
Sodium acetate and the like can be exemplified.

Examples of the lead compound include lead naphthenate and lead octylate. Examples of the tin compound include dibutyltin diacetate and dibutyltin dilaurate. Examples of the alcoholate compound include sodium methoxide and sodium ethoxide.

Examples of the phenolate compound include potassium phenoxide, lithium phenoxide, sodium phenoxide and the like. Examples of the metal halide include iron chloride, zinc chloride, zinc bromide, tin chloride and the like. Examples of the metal complex compound include metal complex compounds such as acetylacetone metal salt.

These catalysts can be used alone or in combination of two or more kinds.
The amount is preferably 0.001 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 00 parts by mass. [ Foam stabilizer ] As the foam stabilizer according to the present invention, a conventionally known silicon-containing organic surfactant is used. Specifically, a silicone derivative (alkylene oxide-modified polydimethylsiloxane with an alkoxy group or Having an active OH group, etc.). Also, so-called nonionic surfactants such as polyoxyethylene octadecylamine and long-chain fatty acid alkylol amide can be used as the foam stabilizer.

As such a foam stabilizer, for example, S
Z-1127, SZ-1142, SZ-1605, SZ
-1642, SZ-1645, SZ-1649, SZ-
1655, SZ-1675, SZ-1694, SZ-1
711, L-580, L-5740, L-5420, L
-5421, L-5440, etc. (these are trade names, manufactured by Nippon Unicar Co., Ltd.), SF-2935F, SF-2938
F, SF-2940F, SF-2945F, SF-29
08, SRX-294A, SH-190, SH-19
2, SH-193, etc. (above, trade names, manufactured by Dow Corning Toray Silicone Co., Ltd.), F-327, F-34
5, F-305, F-388, F-394, etc. (these are trade names, manufactured by Shin-Etsu Chemical Co., Ltd.), TG-B-8404,
TG-B-8461, TG-B-8462, TG-B-
8466 and TG-B-8467 (trade names, manufactured by Goldschmidt, silicone foam stabilizer).

These foam stabilizers can be used alone or in combination of two or more kinds. The use amount thereof is preferably 0.1 to 10 parts by mass, more preferably 100 parts by mass of the polyol. 1 to 5 parts by mass is desirable. [Chain extender / crosslinking agent] In the present invention, if necessary,
A chain extender or a crosslinking agent can be used.

As the chain extender, ethylene glycol,
Propylene glycol, diethylene glycol, triethylene glycol, 1,3-butanediol, 1,4-
And dihydric alcohols such as butanediol.
As the crosslinking agent, glycerin, polyhydric alcohols such as diglycerin, triethanolamine, diethanolamine, alkanolamines such as monoethanolamine,
Examples thereof include aliphatic amine compounds such as ethylenediamine, diethylenetriamine, and thiethyleneethyleneamine. Aniline, 2,4-tolylenediamine, 2,2
Aromatic amines such as 6-tolylenediamine, bisphenol A, bisphenol F, hydroquinone, aromatic alcohols such as resorcinol, novolak and resol, pentaerythritol, sorbitol and the like can also be used. [Other Additives] In the present invention, other various additives can be added according to the use and purpose. Examples of such additives include a flame retardant, an antioxidant, a coloring agent, and a viscosity reducing agent. [Method for Producing Rigid Polyurethane Foam] The method for producing a rigid polyurethane foam according to the present invention comprises: a polyol containing the specific cyclic urea compound in its skeleton or a mixed polyol containing the polyol and another polyol; It can be produced from an isocyanate and, if necessary, a foaming agent, a catalyst, a foam stabilizer, and other additives.

The foaming may be performed in any state, but a method in which the foaming is performed in a mold having a shape or a shape similar to the shape of a molded product is preferable. It is preferable that the polyisocyanate and the polyol are mixed immediately before foaming, and the other components are generally preliminarily mixed with the polyisocyanate or the polyol, if necessary. Alternatively, the stored amount may be appropriately used. For the mixing of other components, the combination of the mixing, the mixing order, the storage time after the mixing, and the like can be determined as appropriate.

Among the components constituting such a mixture, components other than the polyisocyanate, that is, a mixture of a polyol, a foaming agent, a catalyst, a foam stabilizer, a cross-linking agent, and other additives as necessary are mixed with a resin preform. Sometimes called a mix. The composition of each component in the resin premix can be appropriately set depending on the desired performance of the rigid polyurethane foam. Such a resin premix can be reacted with a polyisocyanate to produce a rigid polyurethane foam.

When such a resin premix is used, the viscosity of the resin premix is preferably 1000 mPa · s / 25 ° C. or less from the viewpoints of mixing properties in a foaming machine and foam moldability. As a method for mixing the components, either dynamic mixing or static mixing may be used, or both methods may be used in combination. As a mixing method by dynamic mixing, a method of mixing with a stirring blade or the like can be given. Examples of the mixing method by static mixing include a method of mixing in a machine head mixing chamber of a foaming machine, and a method of mixing in a liquid feed pipe using a static mixer or the like.

When mixing is performed immediately before foaming or when mixing a gaseous component such as a physical foaming agent and a liquid component, the mixing is performed by static mixing, and when mixing storable components is performed by dynamic mixing. Is preferred. The mixing temperature and pressure can be arbitrarily set as required depending on the quality of the target rigid polyurethane foam, the type and composition of the raw material, and heating can be performed as necessary before mixing.

For example, each of the starting components is placed at a liquid temperature of 10 to 50.
A rigid polyurethane foam can be obtained by stirring and mixing at a temperature of 15 ° C., preferably 15 to 30 ° C., and introducing the mixture into an open mold or, if necessary, under a high pressure into a closed mold whose temperature can be controlled as required.
In this case, the mold (mold) temperature is preferably 20 to 110 ° C, preferably 30 to 60 ° C, and particularly preferably 45 to 55 ° C. [Rigid polyurethane foam] The rigid polyurethane foam according to the present invention obtained as described above contains a specific amount of a structural unit derived from a cyclic urea-based compound, and the obtained rigid polyurethane foam has heat insulation performance, dimensional stability, Excellent in compressive strength, thermal conductivity, moldability, etc. The heat transfer coefficient is preferably 16.8 to 25.5 mW / mK,
More preferably, it is desirable to be 16.8 to 23 mW / mK. Further, the core density of the foam is preferably 2
-100 kg / m ³ , more preferably 10-50 kg
/ M ³ .

The rigid polyurethane foam according to the present invention is useful as a heat insulating material or a heat insulating structural material for refrigerators, freezers, building materials, ships or vehicles, and the like.
In addition, the cyclic urea-based compound is easily and easily available in large quantities as a recycled material from a wide range of rigid polyurethane foams, and the physical properties are equal to or more than those of existing rigid polyurethane foams. Therefore, the rigid polyurethane foam and the method for producing the same according to the present invention are effective recycle methods of the rigid polyurethane foam.

[0053]

The rigid polyurethane foam according to the present invention contains a specific amount of a structural unit derived from a cyclic urea-based compound. The obtained rigid polyurethane foam has heat insulation performance, dimensional stability, compressive strength, thermal conductivity, Excellent in moldability. Further, the cyclic urea-based compound serving as a raw material of the polyol can be easily obtained by decomposing and regenerating a rigid polyurethane foam, and the physical properties of the obtained rigid polyurethane foam are equal to or higher than those obtained when using other polyols. Yes, this is an effective method for circulating and using raw materials for rigid polyurethane foam.

[0054]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” means “parts by mass”. [Raw materials] The raw materials used in Examples and Comparative Examples are as follows. Monoethanolamine: MEOA manufactured by Mitsui Chemicals, Inc. Dimethyl palmitylamine: Farmin DM-60 manufactured by Kao Corporation Polyol 1: hydroxyl group obtained by adding propylene oxide to a mixture of o-toluenediamine and triethanolamine Polyol having a hydroxyl value of 400 mg-KOH / g Polyol 2: a hydroxyl value obtained by adding propylene oxide to a mixture of sucrose and glycerin is 450 mg-
Polyol of KOH / g Polyol 3: Hydroxyl value obtained by adding propylene oxide to pentaerythritol is 450 mg-KOH
/ G polyol Polyol A: polyol having a hydroxyl value of 395 mg-KOH / g obtained according to Synthesis Examples 1-3 Polyol B: polyol having a hydroxyl value of 430 mg-KOH / g obtained according to Synthesis Examples 4-6 L-5440: Polydimethylsiloxane derivative (silicone foam stabilizer), Nippon Unicar Co., Ltd. TG-B-8404: Polydimethylsiloxane derivative (silicone foam stabilizer), Goldschmidt Co., Ltd. Catalyst 1: N, N, N ', N'-tetramethylhexamethylenediamine (catalyst for urethanization), Kao riser manufactured by Kao Corporation
No.1 catalyst 2: N, N, N ', N'-pentamethyldiethylenetriamine (catalyst for urethanization), Kaolyzer N manufactured by Kao Corporation
o.3 Zeonsolve HP: Cyclopentane, Nippon Zeon Co., Ltd.
Isocyanate 1: crude MDI, total NCO% = 31.
3. Polyisocyanate M-200 manufactured by Mitsui Chemicals, Inc. [Physical property measurement method] Core density (kg / m ³ ): Measured in accordance with JIS K 7222. Cell state: Cell diameter, presence / absence of air voids, etc. were visually checked. Flyability: The degree of brittleness (presence / absence) of the urethane surface having a foamed diameter (up to about 3 minutes) was confirmed. Low-temperature dimensional stability (vol%) (volume change rate): The volume was measured before and after standing for 24 hours in an atmosphere of -30 ° C, and the difference was calculated as a change rate. Specifically, ｛(after Vol-Vol
Before) / Vol before｝ × 100. Note that “before Vol” indicates the volume before standing, and “after Vol” indicates the volume after standing for 24 hours. Compressive strength (longitudinal) (MPa): Measured according to JIS K 7220. Compressive strength (horizontal) (MPa): Measured in accordance with JIS K 7220. Thermal conductivity (mW / mK): Measured in accordance with JIS A 1412 using EKO SEIKI HC-072. Standard condition of test specimen condition and test place is JIS K
Compliant with 7100.

[0055]

[Synthesis Example 1] [Preparation of rigid polyurethane foam 1] A polyol resin was prepared by mixing 100 parts of polyol 3, 2 parts of L-5440, 2.5 parts of catalyst 1 and 20 parts of Zeonsolve HP. This polyol resin and isocyanate 1 were mixed in an amount of 118 parts by high-speed stirring, dropped into a wooden housing, and foam-hardened to obtain a rigid polyurethane foam 1 (form 1).

[0056]

[Synthesis Example 2] [Decomposition of Rigid Polyurethane Foam 1] 400 g of monoethanolamine was charged into a 2-liter separable flask equipped with a condenser, heated to 150 ° C., and 800 g of foam 1 fragment was added to the flask. Was intermittently supplied, and mixed and stirred at this temperature for 26 hours to decompose Form 1. The decomposition product was brown. The decomposition product was silylated with BSA (N, O, -bis (trimethylsilyl) acetamide). When the obtained product was analyzed by gas chromatography (GC), the main product was an amine corresponding to isocyanate M-200,
It was confirmed to be polyol 1, monoethanolamine and N-hydroxyethylimidazolidone (HEIM). The decomposition product has a viscosity of 9250 centipoise (25 ° C.), pH = 11.1 and a total active hydrogen value of 929 mg.
KOH / g.

[0057]

Synthesis Example 3 [Addition of propylene oxide] Synthesis Example 2
670 g of the decomposition product obtained in the above was charged into a 2.5 liter autoclave, and the mixture was subjected to PO
(Propylene oxide), 105-110 ° C
The addition reaction was continued until the pressure drop of PO disappeared. Remove PO
Thereafter, 6.9 g of dimethyl palmitylamine was added, and PO was recharged with stirring to carry out an addition reaction, thereby synthesizing a regenerated polyol A. After PO removal, the reaction product was analyzed. As a result, the hydroxyl value was 395 mgKOH / g, and the viscosity was 1780.
0 centipoise (25 ° C.) and pH was 11.7.

[0058]

[Synthesis Example 4] [Preparation of rigid polyurethane foam 2] An electric refrigerator marketed as a product is selected according to an arbitrary production age, and the rigid polyurethane foam used in each refrigerator is mixed at an arbitrary mixing ratio and uniformly pulverized. Thus, a rigid polyurethane foam 2 (form 2) was obtained.

[0059]

[Synthesis Example 5] [Decomposition of rigid polyurethane foam 2] 400 g of monoethanolamine was charged into a 2-liter separable flask equipped with a condenser and heated to 150 ° C. Was intermittently supplied, and mixed and stirred at this temperature for 30 hours to decompose Form 2. The decomposition product was brown. The viscosity of the decomposition product is 1200 centipoise (25 ° C.),
The total active hydrogen value was 1360 mg KOH / g.

[0060]

[Synthesis Example 6] [Addition of propylene oxide] Synthesis Example 5
514 g of the decomposition product obtained in the above was charged into a 2.5 liter autoclave, and the mixture was subjected to PO
(Propylene oxide), 105-110 ° C
The addition reaction was continued until the pressure drop of PO disappeared. Remove PO
Thereafter, 4.2 g of KOH was added, and PO was recharged with stirring to carry out an addition reaction, thereby synthesizing a regenerated polyol B.
After PO removal, the reaction product was analyzed and the hydroxyl value was 43
0 mg KOH / g, viscosity 2030 centipoise (25
° C) and pH was 10.0.

[0061]

Examples 1 and 2, Comparative Example 1 Polyol resin raw materials were charged into a 1-liter polypropylene cup at the ratios shown in Table 1, and mixed so that air was not entrained. And then add 500 g with a high-speed rotating lab stirrer.
High-speed stirring and mixing were performed at a rotation speed of 0 to 7000 rpm for about 5 seconds. The resulting mixture is placed in a wooden box (200 × 200 × 2
00 mm), and polyurethane was foamed. Cream time (CT), Gel time (GT) and Tack free time (TFT) in the foam hardening process
Are shown in Table 1. Further, the core density, cell state, flyability, dimensional stability, compressive strength (longitudinal), and compressive strength (horizontal) of the obtained foam were measured.

Further, the polyol resin raw materials were placed in a 1-liter polypropylene cup at the composition ratios shown in Table 1 and mixed so that air was not entrained. Then, isocyanate 1 was added so that the index became 110, and high-speed rotation was performed. About 5 at 5000-7000 rpm with a lab stirrer
High-speed stirring and mixing for 2 seconds (similar to free foaming using a wooden box so far), quickly put this mixture into an aluminum vertical panel jig (360 x 395 x 35 mm) temperature-controlled to 40 ° C, Polyurethane was foamed. At this time, the polyurethane was allowed to flow out of the mold without sealing after the mixture was charged. After foaming and curing, the mold was removed, cut one day later, and the core density and thermal conductivity were measured. Table 1 shows the above results. As shown in Table 1, when the regenerated polyol according to the present invention is used, a rigid polyurethane foam having good reactivity and various physical properties can be obtained.

[0063]

[Table 1]

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) // (C08G 18/50 (C08G 18/50 101: 00) 101: 00) B29K 75:00 B29K 75:00 C08L 75 : 00 C08L 75:00 (72) Inventor Osamu Hayashi 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture F-term (reference) 2E001 DD01 GA12 GA43 HD03 4F301 AA29 BF08 BF19 BF31 CA09 CA23 4J034 BA09 DA01 DB03 DB04 DC50 DF01 DF14 DG01 DG03 DG04 DG06 DG22 DG25 HA01 HA06 HA07 HC03 HC12 HC22 HC64 HC71 JA01 KC02 KC08 KC17 KC35 KD02 KD04 KD11 KD12 NA01 NA03 NA06 NA08 QB16 QC01 RA14 RA19

Claims (7)

[Claims] [Claim 1] The following general formula [I] In the formula [I], m and n are each independently an integer of 1 to 10, and R ¹ and R ² are each independently a hydrogen atom or an alkyl group. A rigid polyurethane foam, which is contained in an amount of 0.03% by mass or more and 10% by mass or less. 2. In the structural unit represented by the formula [I],
The rigid polyurethane foam according to claim 1, wherein n and m in the formula [I] are each independently an integer of 1 to 3. 3. The rigid polyurethane foam according to claim 1, wherein a heat transfer coefficient of the rigid polyurethane foam is in a range of 16.8 mW / mK or more and 25.5 mW / mK or less. 4. The rigid polyurethane foam according to claim 1, wherein a core density of the rigid polyurethane foam is in a range of 2 kg / m ³ or more and 100 kg / m ³ or less. 5. A compound represented by the following general formula [I]: [In the formula [I], m and n are each independently an integer of 1 to 10, and R ¹ and R ² are each independently a hydrogen atom or an alkyl group.] A method for producing a rigid polyurethane foam, comprising using a polyol. 6. The polyol contains a structural unit derived from the compound represented by the general formula [I] in an amount of 0.05% by mass or more and 20% by mass or less in the polyol. A method for producing a rigid polyurethane foam according to claim 5. 7. A heat insulating material comprising the rigid polyurethane foam according to claim 1.