JP2000017036A - Rigid polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a carbon dioxide gas blown rigid polyurethane foam excellent in flame retardance and dimension stability. SOLUTION: The objective rigid polyurethane foam can be obtained by mixing a polyisocyanate component, a polyol component, carbon dioxide gas as the blowing agent, a catalyst, a foam stabilizer, and other auxiliaries and foaming the resulting mixture. The resulting foam has a cell diameter of 50-400 μm, a ratio of closed cells to the total of cells of not less than 50%, a core density of 20-45 kg/m3, an oxygen index (JIS K7201) of not less than 22, an absolute value of the rate of change in dimension, after being left to stand at a temperature of 50-70 deg.C for 24 hours in an environment of the relative humidity of not less than 90%, of not greater than 5%, and a thickness of 15-30 mm, and conforms to flame retardance third or higher class according to JIS A1321.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rigid polyurethane foam, and more particularly to a method of mixing and foaming a polyisocyanate component and a compounded liquid obtained by mixing a polyol component, a foaming agent, a catalyst, a foam stabilizer and other auxiliaries. And a rigid polyurethane foam obtained by the method.

[0002]

2. Description of the Related Art Rigid polyurethane foams are widely used as heat insulating materials for houses, refrigerators and the like because of their excellent heat insulating properties and self-adhesive properties.

[0003] Rigid polyurethane foams used in these applications are generally foamed by mixing a polyisocyanate component and a compounded liquid obtained by mixing a polyol component, a foaming agent, a catalyst, a foam stabilizer and other auxiliaries with a mixing head. In this method, a good heat-insulating layer of a rigid polyurethane foam can be formed by a simple operation of directly spraying and applying to an object to be applied.

On the other hand, as a panel material used for heat insulation and partitioning in a refrigerated / frozen warehouse or a clean room, a heat insulating panel has been developed in which a metal plate or a plywood for structure is used as a face material and a hard polyurethane foam having high heat insulating performance is sandwiched. Has been put to practical use.

[0005] Such a heat insulating panel using a rigid polyurethane foam as a heat insulating material is generally prepared by mixing a polyisocyanate component with a compounded liquid obtained by mixing a polyol component, a foaming agent, a catalyst, a foam stabilizer and other auxiliaries. It is manufactured by an injection molding method in which a rigid polyurethane foam raw material obtained by foaming is injected into a hollow portion of a hollow panel body having a hollow portion composed of a surface material and a side frame material and is integrally molded. Injection molding is widely used as a typical method for manufacturing heat-insulating panels using rigid polyurethane foam because the product dimensions can be arbitrarily designed, and since it can be molded integrally with the surface material and has high productivity. Have been.

For example, as a plate-like material used for heat insulation in a commercial warehouse or the like, a laminate board material obtained by laminating non-combustible paper or gypsum face material on hard urethane foam, a metal decorative face material, or a ceramic face material is used. There is a siding material and the like, such an insulation board,
Generally, a polyisocyanate component, a polyol component,
After mixing a foaming agent, a catalyst, a compounding solution prepared by mixing a foam stabilizer and other auxiliaries, and hard foam raw material obtained by foaming, a paper, a veneer plate, a metal plate, a gypsum board, etc. are laminated and molded. It is manufactured by a continuous foaming method of cutting into predetermined dimensions. A typical example of the molding method by continuous foaming is a double conveyor system in which a rigid polyurethane foam raw material is discharged from a mixing head onto a surface material sent out by a pair of upper and lower belt conveyors, and pressed and molded in a foaming process. According to this method, the dimensions of the product can be arbitrarily designed, and it can be integrally molded with the surface material in one step, and the productivity is high.

[0007]

In rigid polyurethane foam, dichloromonofluoroethane (HCFC-141) which is currently used as a main blowing agent is used.
b) has a problem of depletion of the ozone layer. Hydrofluorocarbon (HFC), which does not destroy the ozone layer, has been proposed as a candidate for a next-generation foaming agent, but on the other hand, it has a problem of strong global warming action. For this reason, development of a technique for foaming without using these fluorine-based foaming agents has been one of the issues.

Therefore, rigid polyurethane foams produced by airless spray foaming are required to have excellent spray stability, workability and flame retardancy without using these alternative foaming agents.

On the other hand, a rigid polyurethane foam as a heat insulating material of a heat insulating panel used for a house or other uses is capable of maintaining stable heat insulating properties and airtightness for a long period of time, and also uses the above alternative foaming agent. It is required to show good flame retardancy without using, and to be hard to spread in the event of fire.

That is, even if a plywood is used as a surface material, even if a metal surface material is used, sufficient fire resistance cannot be obtained depending on the material and thickness of the surface material, the panel structure, and the like. In the event of a fire, the internal rigid polyurethane foam may ignite in a short time. Therefore, the flame retardancy of the rigid polyurethane foam is extremely important for use as a heat insulating panel.

In addition, the dimensional change rate when left in a high-temperature and high-humidity environment is small, regardless of whether it is made by airless spray foaming, injection molding or continuous foaming molding (hereinafter, this property is referred to as "characteristic"). (We call it "weather resistance dimensional stability.")
Is also an important required characteristic.

The present invention has been made in view of the above-mentioned conventional circumstances, and uses HCFC-141b or HFC as a foaming agent.
It is an object of the present invention to provide a rigid polyurethane foam which is excellent in flame retardancy and also has excellent weather dimensional stability.

[0013]

The rigid polyurethane foam of the present invention comprises a rigid polyurethane foam obtained by mixing and foaming a polyisocyanate component, a polyol component, a foaming agent, a catalyst, a foam stabilizer and other auxiliaries. A rigid polyurethane foam using carbon dioxide gas as the blowing agent, the foam has a cell diameter of 50 to 400 μm, and the proportion of closed cells among the cells of the foam (hereinafter referred to as “closed cell rate”) is 50. % Or more, the core density is 20 to 45 kg / m ³ , and the oxygen index (J
IS K7201) is 22 or more and the temperature is 50 to 70.
The absolute value of the dimensional change rate of the core portion after standing for 24 hours in an environment of 90 ° C. and a relative humidity of 90% or more is 5% or less,
It is characterized in that the core portion has a thickness of 15 to 30 mm and conforms to JIS A1321 flame retardant class 3 or higher.

With a rigid polyurethane foam having the above-mentioned physical properties, extremely good flame retardancy and weatherable dimensional stability can be obtained after using carbon dioxide gas as a foaming agent.

Since the rigid polyurethane foam of the present invention uses carbon dioxide gas as a foaming agent, it does not destroy the ozone layer and takes into consideration the problem of global warming.

[0016]

Embodiments of the present invention will be described below in detail.

In the rigid polyurethane foam of the present invention, if the cell diameter of the foam is less than 50 μm, the strength of the foam is remarkably reduced, and if it exceeds 400 μm, the foam tends to be rough and stirring of the blended liquid and the polyisocyanate component is not possible. This reflects a sufficient phenomenon, and the flame retardancy is reduced.
Therefore, the foam has a cell diameter of 50 to 400 μm, preferably 50 to 200 μm.

If the closed cell rate of the foam is less than 50%, the flame retardancy is reduced. Therefore, the closed cell rate is 50% or more, preferably 75% or more.

When the core density (core density) is less than 20 kg / m ³ , the strength is remarkably reduced and the core shrinks to 45 kg / m ^3.
If it exceeds, the burning amount of the rigid polyurethane foam increases due to the high density, and it becomes incompatible with JIS A1321 flame retardant class 3. Therefore, the core density is 20 to 45 kg /
m ³ , preferably 25 to 40 kg / m ³ .

The oxygen index of the core part (JIS K720)
If 1) is less than 22, the flame retardancy is insufficient. The oxygen index (O.I.) is one of the evaluation items of flame retardancy, and JIS K7201 is a representative measuring method. JI
The measurement method using SK7201 is the combustion part (combustion cylinder)
The oxygen or nitrogen flow rate to the combustion part is adjusted in order to burn the sample placed at a certain distance or time, and the oxygen index is calculated from the oxygen flow rate and the nitrogen flow rate at this time by the following formula. It is generally said that the higher the oxygen index, the higher the flame retardancy.

[0021]

(Equation 1)

A rigid polyurethane foam in which the absolute value of the dimensional change of the core portion after being left for 24 hours in an environment of a temperature of 50 to 70 ° C. and a relative humidity of 90% or more exceeds 5%, has a poor weather resistance and dimensional stability. Inferior and unsuitable for various heat insulating materials. Therefore, the absolute value of the dimensional change is set to 5% or less, preferably 3% or less.

The temperature is 50 to 70 ° C. and the relative humidity is 90%.
The dimensional change of the core portion after leaving for 24 hours in the above environment (hereinafter referred to as “wet heat dimensional change”) can be measured, for example, by the following method. Also in the examples, the dimensional change in wet heat was measured by the following method.

[Measurement Method of Dimensional Change in Wet Heat] A sample of a rigid polyurethane foam having a width of 5 cm, a length of 5 cm and a thickness of 3 cm was left for 24 hours in an environment of a temperature of 50 ° C. and a relative humidity of 95%. Of width (or length) and thickness of 1
Assuming that it is 00%, the width (or length) and the dimensional change rate of the thickness of the sample after standing are obtained.

The cell diameter, closed cell rate, core density, oxygen index, and wet heat dimensional change rate are satisfied and the thickness 1
The rigid polyurethane foam of the present invention, which is 5 to 30 mm and conforms to JIS A1321 flame retardant class 3 or higher, is obtained by mixing a polyisocyanate component, a polyol component, carbon dioxide as a foaming agent, a catalyst, a foam stabilizer, and other auxiliaries. In producing a rigid polyurethane foam by foaming, for example, using a polyol component, a polyisocyanate component, a catalyst, etc. as exemplified below, using a larger amount of a foaming agent than before, or a liquid at the time of foaming It can be produced by increasing the temperature or pressure.

Polyol Component The polyol component includes a hydroxy compound and one or more polybasic acid components selected from the group consisting of o-phthalic acid, m-phthalic acid, p-phthalic acid and derivatives thereof. It is preferable to use those containing 40% by weight or more of a polyester polyol compound (hereinafter referred to as "phthalic acid-based polyester polyol") obtained by subjecting the polyester polyol to an esterification reaction.

By using a large amount of the phthalic acid-based polyester polyol containing an aromatic ring as the polyol component, stable flame retardancy can be obtained. If the content of the phthalic polyester polyol in the polyol component is less than 40% by weight, sufficient flame retardancy cannot be obtained. The content of the phthalic acid-based polyester polyol in the polyol component is preferably 55% by weight or more, and more preferably 60% by weight or more. On the other hand, the flame retardant effect can be stably obtained.

Examples of the hydroxy compound forming the phthalic acid-based polyester polyol include ethylene glycol and diethylene glycol, and examples of the phthalic acid derivative include diethyl phthalate and dimethyl phthalate. In addition, polyester polyols regenerated and produced from residues such as PET (polyethylene terephthalate) are also included. The preferred hydroxyl value of the phthalic acid-based polyester polyol is from 150 to 450. The phthalic acid-based polyester polyol is particularly suitable for m-
Those having a high proportion of phthalic acid and / or p-phthalic acid are preferred from the viewpoint of flame retardancy.

The content of the phthalic acid-based polyester polyol is a ratio as pure phthalic acid-based polyester polyol, and is a hydroxy compound or a polybasic compound which is contained in a product of the ester synthesis reaction in an unreacted state. It does not include acid components and other additives.

For the quantitative analysis of such unreacted substances and additives, an instrumental analysis method such as gas chromatography can be adopted. In the present invention, the quantitative analysis was performed using gas chromatography. Specifically, a sample was dissolved in a solvent such as chloroform or methanol, injected into a chromatograph, and subjected to an internal standard method under the following analysis conditions.

[Gas Chromatography Conditions] Column: SGE, BP21, 25m, 0.22I. D. , 0.25 μm film • Internal standard: 3,5-di-tert-butyl-4-hydroxytoluene • Heating conditions: 100 ° C to 230 ° C (5 minutes), heating rate 10 ° C / min • Split ratio: 1 Injection temperature: 240 ° C. Detector: FID 280 ° C. In the present invention, phenol and / or its derivative (substituted or adducted phenol) other than the phthalic polyester polyol described above is used as the polyol component. A polyether polyol as an initiator may be used. For example, a Mannich-modified polyol obtained by subjecting the phenol and / or phenol derivative to Mannich modification, that is, phenol or a phenol derivative such as nonylphenol or alkylphenol is converted to a secondary amine such as formaldehyde and diethanolamine, ammonia, or a primary amine. A polyether polyol obtained by subjecting to a Mannich modification and subjecting an alkylene oxide such as ethylene oxide or propylene oxide to ring-opening addition polymerization may be used. In addition, phenol and cresol, xylenol, a benzylic ether type obtained by synthesizing a phenol derivative such as one obtained by adding one to several moles of ethylene oxide or propylene oxide to a hydroxyl group of phenol and an aldehyde, for example, formaldehyde. A phenol resin may be used. Since the polyether polyol having such a phenol and / or a derivative thereof as an initiator has a high self-reaction activity and a relatively high flame retardancy, by using this polyether polyol, the flame retardant performance at the time of spray foaming is improved. The reaction can proceed promptly without significant damage. However, if the polyether polyol containing phenol and / or a derivative thereof as an initiator in the polyol component exceeds 20% by weight, the flame retardant performance deteriorates. When a polyol is used, its proportion in the polyol component is 20% by weight.
Hereinafter, it is particularly preferable to be 5 to 15% by weight.

In the present invention, in addition to phthalic acid-based polyester polyol and polyether polyol having phenol and / or a derivative thereof as an initiator, ethylenediamine and tolylenediamine are used as polyol components as long as the object of the present invention is not impaired. , Sucrose,
A polyether polyol compound having an initiator different from phenol and / or a derivative thereof, such as amino alcohol and diethylene glycol, is used in an amount of 30% by weight based on the total polyol component.
You may use together in the following ranges.

Polyisocyanate component A polyisocyanate compound represented by the following general formula (I), in which the proportion of trinuclear triisocyanate with n = 1 in the polyisocyanate compound is 20 mol% or more (hereinafter, referred to as The ratio is referred to as “trinuclear content in polyisocyanate”), which is represented by the following structural formula (II):
4′-diphenylmethane diisocyanate (hereinafter “4,
4'-MDI ". ) (Hereinafter, this ratio is referred to as “content of 4,4 ′ isomer in polyisocyanate”) is at least 35 mol% (hereinafter, such a polyisocyanate is referred to as “nucleus-controlled polyisocyanate”). Are preferred.

[0034]

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[0035]

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When the content of the trinuclear compound in the polyisocyanate of the nucleus-controlled polyisocyanate is less than 20 mol%, or when the content of the 4,4′-isomer in the polyisocyanate is less than 35 mol%, , Good flame retardancy cannot be achieved.

The nucleus controlling polyisocyanate of the present invention preferably has a trinuclear content of 2 in the polyisocyanate.
It is at least 5 mol%, and the content of the 4,4′-isomer in the polyisocyanate is preferably at least 36 mol%, more preferably at least 38 mol%.

In the present invention, the trinuclear content and the 4,4 ′ content in the polyisocyanate are determined by gel permeation chromatography (hereinafter referred to as “GPC”) and gas chromatography (hereinafter referred to as “GC”). ), And the number composition of each nucleus was quantified by GPC, and the dinuclear isomer composition was quantified by GC. The quantification by GPC and GC was performed by dissolving each sample in tetrahydrofuran (THF) and chloroform and then injecting it into a chromatogram under the following conditions.

[GPC] Column: SuperH2000 + 3000 Flow rate: 1 m / L of THF Detector: RI [GC] Column: UltraAlloy-PY3, 10 m, 0.25 I. manufactured by FRONTIER LAB D. , 0.1 μm film ・ Rising temperature condition: 70 ° C. (1 minute) to 300 ° C. (heating rate: 25 ° C./min) ・ Injection temperature: 280 ° C. ・ Detector: FID 280 ° C. And the peak area ratio of the trinuclear compound to the total peak area of the polyisocyanate compound in the GPC chromatogram.

The content of the 4,4′-isomer in the polyisocyanate is calculated by calculating the ratio of the peak area of 4,4′-MDI to the total peak area of the binucleate in the GC chromatogram,
It was calculated by the product of this value and the value of the binuclide peak area ratio to the total peak area of the isocyanate compound in the GPC chromatogram.

In the present invention, the unit of the peak area ratio of the isocyanate compound on the chromatogram obtained as described above is applied as mol%.

The isocyanate index of the nucleus controlling polyisocyanate is preferably from 130 to 350, and is preferably from 150 to 250 in consideration of the overall performance balance such as improvement of flame retardancy and suppression of shrinkage. More preferred.

In the present invention, as the polyisocyanate component, a polyisocyanate compound other than the above-mentioned nucleus controlling polyisocyanate, for example, an alicyclic isocyanate such as isophorone diisocyanate, an aliphatic isocyanate such as hexamethylene diisocyanate and the like are used. Although it may be used, even in this case, it is necessary that the content of the trinuclear body and the content of the 4,4′-isomer in all the polyisocyanate components are within the range of the present invention.

Catalyst Preferably, a reactive amine catalyst comprising an amine compound containing one or more hydroxyl groups in one molecule, specifically, dimethylaminohexanol, dimethylaminoethoxyethanol, trimethylaminoethylethanolamine, and other quaternary ammonium Use salts and the like.

That is, amine catalysts which have been conventionally used as catalysts for rigid polyurethane foams are compounds such as triethylenediamine, tetramethylhexamethylenediamine, pentamethyldiethylenetriamine, etc. It is presumed that this was the core of combustion because it remained in the free state. Therefore, flame retardancy can be enhanced by using a reactive amine catalyst in place of a conventional amine catalyst. However, these amine catalysts may be used in combination with a reactive amine catalyst as long as the object of the present invention is not impaired.

Incidentally, dibutyltin dilaurate, lead octylate, stannas octoate, potassium octylate (2
Organometallic catalysts such as potassium ethylhexylate) and potassium acetate are indispensable components for urethane bond and promotion of isocyanurate modification, and they do not impair the flame retardancy by use. .

The amount of the above-mentioned reactive amine catalyst varies mainly depending on the environmental temperature conditions of the spraying, but is 10% by weight or less, preferably 5% by weight or less, more preferably 0.1 to 5% by weight based on the polyol component. It is. When the use amount of the reactive amine catalyst exceeds 10% by weight with respect to the polyol component, the flame retardant performance is rather deteriorated, and in the case of the airless spray foamable rigid polyurethane foam, the spray pattern (atomization width) is disturbed, which is preferable. Absent.

The amount of the organometallic catalyst used (the total amount with the reactive amine catalyst when a reactive amine catalyst is used) is preferably 1 to 10% by weight based on the polyol component.

Blowing agent Carbon dioxide gas is used as the blowing agent. Carbon dioxide gas as a foaming agent can be added to the reaction system by a method in which water is added and generated by a reaction between water and isocyanate, or a method in which liquefied carbon dioxide gas is forcibly mixed into raw material components. .

The amount of carbon dioxide used is arbitrarily determined according to the density of the target rigid polyurethane foam.
In the normal case, the content is preferably 12% by weight or less, particularly 2.5 to 8% by weight based on the total of the polyol component and the polyisocyanate component. In particular, when water is reacted with an isocyanate as a foaming agent to generate carbon dioxide gas, the amount of water added is preferably 1 to 3% by weight based on the total of the polyol component and the polyisocyanate component. If the amount of carbon dioxide gas used exceeds 12% by weight based on the total of the polyol component and the polyisocyanate component, the vaporization power becomes too high, the foaming becomes unstable, and the foam is coarse and good foam cannot be obtained. .

Foam stabilizers Any foam stabilizers that are effective for producing rigid polyurethane foams can be used. For example, a silicone-based material such as polyoxyalkylene alkyl ether can be used in a usual amount.

In the present invention, optional components other than those described above, for example, a flame retardant, a filler, and the like can be used as long as the object of the present invention is not hindered.

In the present invention, it is preferable to use the phthalic acid-based polyester polyol in combination with a reactive amine catalyst and / or a nucleus controlling polyisocyanate, and further, a polyether polyol using phenol and / or a phenol derivative as an initiator. By using together, more excellent characteristics can be obtained.

For the rigid polyurethane foam of the present invention, for example, in the case of an airless spray foamable rigid polyurethane foam, a compounding component obtained by mixing a foaming agent, a catalyst, a foam stabilizer and other auxiliaries with a polyol component, and a polyisocyanate component are used. Mix by a mixing head at 30 to 50 ° C. according to an ordinary method, and apply a discharge pressure of 40 to 80 kg / cm to the surface to be processed.
It can be easily manufactured by spraying and foaming in ² .

In the case of a heat insulating panel by injection molding, a blending component obtained by mixing a polyol component with a foaming agent, a catalyst, a foam stabilizer and other auxiliaries, and a polyisocyanate component at 15 to 50 ° C. according to a conventional method. It can be easily manufactured by injecting a rigid polyurethane foam raw material obtained by mixing and foaming with a mixing head into a hollow portion of a hollow panel body composed of a surface material and a side frame material, foaming and molding. it can.

The surface material of the hollow panel body varies depending on the purpose of use of the heat insulating panel, but may be a metal or alloy plate such as aluminum, iron, stainless steel, a PVC steel plate, a structural plywood, or the like.
Glued laminated materials, such as an oriented strand board (OSB), are mentioned.

As the side frame material, a resin molded product such as PVC or ABS, wood or the like is generally used.

In the case of a heat insulating board formed by continuous foam molding, a blending component obtained by mixing a foaming agent, a catalyst, a foam stabilizer and other auxiliaries with a polyol component and a polyisocyanate component at 15 to 50.degree. In a rigid polyurethane foam obtained by mixing and foaming with a mixing head,
It can be easily manufactured by a continuous foam molding method or the like in which a surface material is laminated and pressed with a belt conveyor or the like.

The surface material in this case also varies depending on the purpose of use of the heat insulating board, but soft surface materials such as aluminum foil, kraft paper and asphalt felt, and hard surface materials such as gypsum board, wood wool cement board and plywood. Is mentioned.

The size of such a heat insulating board is not particularly limited, but is generally 30 to 20 mm.
The size is about 0 cm x 150 to 800 cm x thickness 1 to 20 cm.

[0061]

The present invention will be described more specifically below with reference to examples and comparative examples. In the following, “%” indicates “% by weight” unless otherwise specified.

Examples 1 and 2 and Comparative Examples 1 and 2 According to the formulation shown in Table 1, first, a mixture A was prepared, and polyisocyanates 1 and 2 were prepared.

The raw materials used are as follows.

Regarding the polyols B and C, the unreacted substances and additives in the polyols were quantified by the above-described gas chromatography analysis method, and the ratio of the pure phthalic polyester polyol was calculated.

For polyisocyanate, the trinuclear content and the 4,4 ′ content in the polyisocyanate were calculated by the composition analysis method described above. Polyol A: Mannich modified polyol manufactured by Daiichi Kogyo Seiyaku Co., Ltd., hydroxyl value 700 Polyol B: Polyether polyol, hydroxyl value 440 manufactured by Asahi Glass Co., Ltd. Polyol C: m, p-phthalic acid base manufactured by Hoechst Celanese Co., Ltd. Polyester polyol, hydroxyl value 240 (content of pure phthalic polyester polyol: 76.2%) Polyol D: m, p-phthalic acid-based polyester polyol manufactured by Toho Rika Kogyo Co., Ltd., hydroxyl value 300 (pure phthalic acid) Based polyester polyol content 64.1
%) Polyol E: o-phthalic acid-based polyester polyol, manufactured by Toho Rika Kogyo Co., Ltd., hydroxyl value 300 (content of pure phthalic acid-based polyester polyol: 77.3%) Polyol F: o, manufactured by Toho Rika Kogyo Co., Ltd. -Phthalic acid-based polyester polyol, hydroxyl value 260 (pure phthalic acid-based polyester polyol content 79.8%) Flame retardant: "Phirol P" manufactured by Stoffer Japan K.K.
CF ”Foam stabilizer:“ L5420 ”manufactured by Nippon Unicar Co., Ltd. Catalyst A:“ Kaolyzer No. 1 ”manufactured by Kao Corporation Catalyst B:“ Kaolyzer No. 25 ”manufactured by Kao Corporation Reactive type Amine catalyst dimethylaminohexanol (the number of hydroxyl groups in one molecule is 1) Catalyst C: "Kaolyzer No. 3" manufactured by Kao Corporation Pentamethyldiethylenetriamine Catalyst D: "B-15G" manufactured by Nippon Chemical Industry Co., Ltd. 2-ethylhexyl acid Potassium Blowing agent: Water Polyisocyanate 1: Nippon Polyurethane Co., Ltd. crude diphenylmethane diisocyanate (NCO%:
30.2, trinuclear content in polyisocyanate: 2
8.9 mol%, 4,4′-form content: 36.8 mol%) Polyisocyanate 2: crude diphenylmethane diisocyanate (NCO%: manufactured by Sumitomo Bayer Urethane Co., Ltd.)
31.4, trinuclear content in polyisocyanate: 1
(9.9 mol%, 4,4'-isomer content: 35.2 mol%) Both the mixture A and a predetermined amount of isocyanate 1 or 2 were adjusted to 20 ° C., and stirred at 5000 rpm for 5 seconds with a laboratory mixer. Free foaming on pattern paper. About the obtained foam, density, cell diameter, closed cell rate, oxygen index,
The dimensional change in wet heat and the flame retardancy were examined, and the results are shown in Table 1.

The bubble diameter was calculated from the sampling foam by counting the number of bubbles using a 20 × lens in a predetermined section (25 mm).

The closed cell rate was determined by cutting out the above-mentioned sampling foam into 26 mm × 26 mm × 35 mm and using a closed cell rate measuring device.

The oxygen index is more than 70-
It was determined based on JIS K7201 for a cutout of 150 mm, a width of 6.5 mm, and a thickness of 3.0 mm.

The wet heat dimensional change rate was determined by the above-described measuring method.

The flame retardancy was examined by cutting a foam core and performing a surface test using a flammability tester manufactured by Toyo Seiki Seisaku-Sho, Ltd. (test specimen thickness: 20 mm, heating time: 6 hours).
Minutes).

[0071]

[Table 1]

According to Table 1, according to the present invention, there is provided a rigid polyurethane foam using carbon dioxide gas as a blowing agent,
It can be seen that a rigid polyurethane foam excellent in flame retardancy and weather dimensional stability is provided.

[0073]

As described in detail above, according to the rigid polyurethane foam of the present invention, a rigid polyurethane foam excellent in flame retardancy and weather dimensional stability is provided by using carbon dioxide as a foaming agent.

Continued on the front page F term (reference) 4F074 AA78 AG10 BA32 BA34 BC05 CA12 DA02 DA03 DA12 DA15 DA18 DA23 DA32 4J034 DA01 DB03 DB07 DF16 DF22 DG16 DG22 DH02 DH06 DH10 DJ02 DJ08 DJ09 DJ12 HA01 HA06 HA07 HA08 HA14 HC03 HC52 HC22 HC64 HC65 HC71 HC73 KA01 KB02 KC02 KC17 KC18 KD02 KD12 KE02 NA01 NA03 NA07 NA08 QB01 QB16 QB17 QB19 QC01 RA15

Claims (1)

[Claims] 1. A rigid polyurethane foam obtained by mixing and foaming a polyisocyanate component, a polyol component, a foaming agent, a catalyst, a foam stabilizer and other auxiliaries, wherein a rigid polyurethane foam using carbon dioxide gas as the foaming agent Wherein the cell diameter of the foam is 50 to 400 μm, the proportion of closed cells among the cells of the foam is 50% or more, the core density is 20 to 45 kg / m ³ , and the oxygen index of the core portion ( JIS K7201) is 22 or more. In an environment with a temperature of 50 to 70 ° C and a relative humidity of 90% or more, 2
The absolute value of the dimensional change rate of the core after leaving for 4 hours is 5
% Or less, and the core portion has a thickness of 15 to 30 mm and conforms to JIS A1321 flame retardant class 3 or higher.