JP2008081701A - Polyisocyanate composition and method for producing rigid polyurethane foam by using the composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyisocyanate composition having excellent storage stability even in an ultra-low temperature atmosphere of -5°C and giving a rigid polyurethane foam having excellent adhesiveness to an adherend cooled to an ultra-low temperature of e. g. -5°C, and a method for producing a rigid polyurethane foam by using the polyisocyanate composition. <P>SOLUTION: The polyisocyanate composition is composed of a polymeric MDI, a specific polyether monool, a silicone-based foam stabilizer and a dialkyl glycol ether. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a polyisocyanate composition and a method for producing a rigid polyurethane foam using the composition. More specifically, for example, a polyisocyanate composition capable of providing a rigid polyurethane foam having excellent storage stability in an ultra-low temperature atmosphere of, for example, −5 ° C. and excellent adhesion to an extremely low temperature of, for example, −5 ° C. And a method for producing a rigid polyurethane foam using the polyisocyanate composition.
In the present invention, “rigid polyurethane foam” is a concept including “isocyanurate-modified polyurethane foam” unless otherwise specified.

  Conventionally, rigid polyurethane foam has been widely used as a heat insulating material for refrigerators, refrigerated warehouses, building materials and the like, and for spray applications.

  Polymeric MDI (polyphenylene polymethylene polyisocyanate) including diphenylmethane diisocyanate (hereinafter abbreviated as “MDI”) and an MDI-based multinuclear condensate is used as a polyisocyanate for producing a rigid polyurethane foam.

  On the other hand, as a foaming agent for producing a rigid polyurethane foam, (hydro) chlorofluorocarbons such as 1,1-dichloro-1-fluoroethane, which has been widely used in the past, from the viewpoint of preventing destruction of the ozone layer, etc. Instead, 1,1,1,3,3-pentafluoropropane (hereinafter abbreviated as “HFC-245fa”), 1,1,1,3,3-pentafluorobutane (hereinafter, “HFC-365mfc”). Hydrofluorocarbons such as abbreviations) have begun to be used.

  In addition, from the same viewpoint as described above, a rigid polyurethane foam having a (complete) water foaming formulation using only water as a foaming agent is also introduced.

  However, hydrofluorocarbons and water used as blowing agents are more homogeneously mixed (compatible and dispersible) with urethane raw materials (isocyanate composition and polyol composition) than conventional (hydro) chlorofluorocarbons. There is a problem that it is inferior. If the uniform mixing property (compatibility / dispersibility) between the foaming agent and the urethane raw material is low, the reactivity and foaming efficiency (densification) will decrease, resulting in poor surface finish, reduced strength, In addition to a decrease in dimensional stability and a decrease in heat insulation due to cell roughness, there is a problem in that the adhesive force of the foam to the adherend (casing) decreases.

  Moreover, the rigid polyurethane foam by a water foaming prescription | regulation does not have sufficient adhesive force with respect to a to-be-adhered body.

  Here, the decrease in the adhesive force to the adherend becomes a problem particularly in spraying construction (spraying construction) performed in a low temperature environment. This decrease in the adhesive force to the adherend appears remarkably for an extremely low temperature adherend of, for example, −5 ° C., and this solution is particularly required.

For example, the following method has been introduced as a method for improving the adhesion of a rigid polyurethane foam to an adherend.
(1) An isocyanate group obtained by reacting a hydroxyl group-containing polyether having a number average molecular weight of 150 to 10,000 and having a monovalent organic group having 3 or more carbon atoms at the end and containing 70% by mass or more of an oxypropylene group with an isocyanate. A method using a terminal prepolymer (see Patent Document 1).
(2) A method using an isocyanate group-terminated prepolymer obtained by reacting an active hydrogen group-containing polyether satisfying specific requirements and an active hydrogen group-containing polysiloxane-polyether copolymer satisfying specific requirements with an isocyanate (Patent Document 2) reference).
(3) A method of introducing an active hydrogen group-free polyether that satisfies specific requirements and / or an active hydrogen group-free polysiloxane-polyether copolymer that satisfies specific requirements into an isocyanate (see Patent Document 3).
(4) A method of introducing an active hydrogen group-containing polysiloxane-polyether copolymer that satisfies specific requirements into isocyanate (see Patent Document 4).
(5) A method using an isocyanate group-terminated prepolymer obtained by reacting an active hydrogen group-containing hydrocarbon compound having 3 to 50 carbon atoms and / or an active hydrogen group-containing halogenated hydrocarbon compound having 3 to 50 carbon atoms with an isocyanate. (See Patent Document 5).
(6) A method using an isocyanate group-terminated prepolymer obtained by reacting an active hydrogen group-containing fatty acid ester and / or an active hydrogen group-containing fatty acid amide compound with an isocyanate (see Patent Document 6).
(7) A method of introducing a silicone-based foam stabilizer into an isocyanate group-terminated prepolymer obtained by reacting a polyester polyol having a sulfo group or a sulfonate group in the molecular structure and a polyether monool with an isocyanate, respectively (patent document) 7).

  However, in a conventionally known method including the above methods (1) to (7), for example, a rigid polyurethane foam having a sufficiently high adhesive force is manufactured for an extremely low temperature adherend of −5 ° C. I can't.

  Moreover, the polyisocyanate used when manufacturing a rigid polyurethane foam is also required to have storage stability of the polyisocyanate at the construction site. Therefore, it is necessary to obtain storage stability in an ultra-low temperature atmosphere of, for example, −5 ° C. in addition to the above-described improvement in adhesiveness.

JP 2002-322231 A JP 2002-356530 A JP 2002-356532 A JP 2002-356533 A JP 2002-356534 A JP 2002-356535 A JP-A-2005-213306

  The present invention has been made based on the background as described above.

  The first object of the present invention is a polyisocyanate composition capable of obtaining a rigid polyurethane foam having good adhesion to an extremely low temperature adherend of, for example, −5 ° C. and excellent in shape stability. To provide things.

  The second object of the present invention is to provide a polyisocyanate composition for producing a rigid polyurethane foam which is excellent in storage stability even in an ultra-low temperature atmosphere of, for example, -5 ° C.

  The third object of the present invention is to have a good adhesiveness to an ultra-low temperature adherend of −5 ° C. in a foaming formulation using hydrofluorocarbons and / or water as a foaming agent, and is desired. An object of the present invention is to provide a method for producing a rigid polyurethane foam having excellent mechanical properties and the like.

  A fourth object of the present invention is to provide a method for producing a rigid polyurethane foam having the above-described excellent performance even by a spray method.

  In order to solve these series of problems (to achieve the object), the present inventors have intensively studied, and as a result, a polyisocyanate composition for producing a rigid polyurethane foam having a specific configuration is solved. As a result, the present invention was found to be very effective.

  That is, the present invention is as follows (1) to (4).

(1) (A1) 20 to 80% by mass of the diphenylmethane diisocyanate isomer mixture (a1d), 80 to 20% by mass of a trinuclear or higher diphenylmethane diisocyanate polynuclear condensate (a1p) (provided that (a1d) + (a1p) ) = Polymeric MDI (100% by mass as (A1)),
(A2) a polyether monool having a number average molecular weight of 150 to 10,000,
(A3) a polyisocyanate composition obtained by reacting and mixing a silicone-based foam stabilizer that may contain a hydroxyl group, and (A4) a compound represented by the following general formula (1),
(A1) = 98.95-88.0% by mass,
(A2) = 0.5-5% by mass,
(A3) = 0.05-2.0 mass% and (A4) = 0.5-5.0 mass%
(However, (A1) + (A2) + (A3) + (A4) = 100 mass% as the whole composition) A polyisocyanate composition for producing rigid polyurethane foam,

(2) (A1) 4,4′-diphenylmethane diisocyanate (4,4′-MDI) is 60 to 95% by mass, and diphenylmethane diisocyanate isomers (isomer MDI) other than 4,4′-diphenylmethane diisocyanate are 5 to 5%. Diphenylmethane diisocyanate isomer mixture (a1d) composed of 40% by mass is 20 to 80% by mass, and trinuclear or higher diphenylmethane diisocyanate polynuclear condensate (a1p) is 80 to 20% by mass (provided that (a1d) + (a1p) = Polymeric MDI (100% by mass as (A1)),
(A2) A polyisocyanate composition obtained by reacting and mixing a polyether monool having a number average molecular weight of 150 to 10,000 (A3) a hydroxyl group-containing silicone-based foam stabilizer and (A4) diethylene glycol dimethyl ether,
(A1) = 98.95-88.0% by mass,
(A2) = 0.5-5% by mass,
(A3) = 0.05-2.0 mass%, and (A4) = 0.5-5.0 mass%,
(However, (A1) + (A2) + (A3) + (A4) = 100% by mass as the whole composition)
A polyisocyanate composition for producing rigid polyurethane foam, characterized in that

(3) A hard material that reacts the polyisocyanate composition according to (1) or (2) with the polyol (B) in the presence of the foaming agent (C), the catalyst (D), and the foam stabilizer (E). A process for producing a polyurethane foam, characterized in that hydrofluorocarbon and / or water is used as the foaming agent (C).

(4) The method for producing a rigid polyurethane foam according to (3), wherein the rigid polyurethane foam is formed on an adherend by a spray method.

  By using the polyisocyanate composition of the present invention, for example, it is possible to produce a rigid polyurethane foam having good adhesiveness to an extremely low temperature adherend of -5 ° C and excellent in shape stability. it can.

  In addition, since the polyisocyanate composition of the present invention is excellent in storage stability even in an ultra-low temperature atmosphere of, for example, -5 ° C, for example, in a construction site under an ultra-low temperature atmosphere of, for example, -5 ° C, Stable supply of the isocyanate composition is possible.

  These excellent effects are further achieved in a foaming formulation using hydrofluorocarbons and / or water as a foaming agent, having good adhesion to an adherend at an ultra-low temperature of −5 ° C., and a desired machine. It is possible to provide a method for producing a rigid polyurethane foam having excellent physical properties.

  In particular, when a rigid polyurethane foam is formed on an adherend by a spray method, it is sufficiently possible to obtain a desired rigid polyurethane foam even in a construction under an ultra-low temperature atmosphere of, for example, −5 ° C.

  The present invention will be described in further detail.

The polyisocyanate composition of the present invention comprises (A1) a diphenylmethane diisocyanate-based polynuclear compound having a dinuclear diphenylmethane diisocyanate isomer mixture (hereinafter abbreviated as “MDI”) (a1d) of 20 to 80% by mass and a trinuclear or more. Polymeric MDI in which a condensate (hereinafter abbreviated as “MDI polynuclear condensate”) (a1p) is 80 to 20% by mass (however, (a1d) + (a1p) = (A1) is 100% by mass)), (A2 ) A polyether monool having a number average molecular weight of 150 to 10,000, (A3) a silicone-based foam stabilizer that may contain a hydroxyl group, and (A4) a compound represented by the following general formula (1): Become
(A1) = 98.95-88.0% by mass,
(A2) = 0.5-5% by mass,
(A3) = 0.05-2.0 mass% and (A4) = 0.5-5.0 mass%
(However, (A1) + (A2) + (A3) + (A4) = 100% by mass as the whole composition)
Consists of.

<Polymeric MDI (A1)>
The polymeric MDI (A1) constituting the polyisocyanate composition of the present invention is a mixture comprising 20 to 80% by mass of MDI (a1d) and 80 to 20% by mass of MDI polynuclear condensate (a1p) (polyphenylene polymethylene poly). Isocyanate). In addition, the sum total of MDI (a1d) and MDI type | system | group multinuclear condensate (a1p) is 100 mass% as polymeric MDI (A1).

  The polymeric MDI (A1) constituting the polyisocyanate composition of the present invention is used in the range of 88.0 to 98.95% by mass when the entire polyisocyanate composition is 100% by mass.

  Polymeric MDI (A1) can be obtained by converting the amino group of a condensation mixture (polyamine) obtained by the condensation reaction of aniline and formalin to an isocyanate group by phosgenation or the like. By changing the reaction conditions, the composition (nuclear distribution and isomer composition ratio) of the finally obtained polymeric MDI can be controlled.

  The polymeric MDI (A1) used in the present invention is a reaction solution such as a reaction solution after conversion to an isocyanate group, removal of the solvent from the reaction solution, and a bottom solution obtained by distilling and separating part of MDI. It may be a mixture of several different types. Moreover, what mixed MDI (a1d) with the commercially available polymeric MDI may be used.

  The proportion of MDI (a1d) in the polymeric MDI (A1) is in the range of 20 to 80% by mass, preferably in the range of 25 to 75%, in particular, the storage stability in the liquid state in the polymeric MDI (A1), From the viewpoint of providing good workability when forming a rigid polyurethane foam, the range of 26 to 70% is particularly preferable. Here, the ratio of MDI (a1d) is a ratio obtained from the peak area ratio of MDI by GPC (gel permeation chromatography). When the ratio of MDI (a1d) in the polymeric MDI (A1) exceeds 80%, there is a high possibility of problems in terms of storage stability of the polymeric MDI, such as precipitation of crystals due to the MDI (a1d). Tend to be. On the other hand, when this ratio is less than 20%, the viscosity of the polymeric MDI tends to be excessively high, and there is a high possibility that problems will occur in terms of workability such as poor mixing.

  MDI (a1d), which is a binuclear body, is composed of three isomers of 4,4′-MDI, 2,2′-MDI, and 2,4′-MDI. In the present invention, the composition ratio of these isomers is not particularly limited, but the storage stability is excellent even under conditions more severe than −5 ° C., such as −20 ° C. It is preferable that the 4,4′-MDI content is in the range of 60 to 95% from the viewpoint of having the properties (crystals and the like do not precipitate). The composition ratio of isomers can be determined from a calibration curve based on the area percentage of each peak obtained by GC (gas chromatography).

  The average number of functional groups of the polymeric MDI (A1) is preferably 2.2 or more, and more preferably 2.2 to 3.1.

  The isocyanate group content of the polymeric MDI (A1) is preferably 28 to 33% by mass, more preferably 28.5 to 32.5% by mass.

  The acidity of the polymeric MDI (A1) is preferably 0.001 to 0.2% by mass, and more preferably 0.003 to 0.15% by mass. Thereby, the storage stability and suitable reactivity of the polyisocyanate composition obtained are ensured. The “acidity” means a value obtained by converting an acid component that reacts with alcohol at room temperature and liberated into hydrogen chloride, and is measured according to JIS K-1603.

<Polyether monool (A2)>
The polyether monool (A2) having a number average molecular weight of 150 to 10,000 used in the present invention is added to the polyisocyanate composition of the present invention with a foaming agent (particularly, a foaming agent comprising hydrofluorocarbons and / or water). It is a component that imparts uniform mixing property, and is used within a range of 0.5 to 5% by mass when the entire polyisocyanate composition is 100% by mass. The polyether monool (A2) having a number average molecular weight of 150 to 10,000 can be represented by the following general formula (2).

In the general formula (2), the organic group (R ¹ ) may have an atom other than a carbon atom and a hydrogen atom, and may or may not have a side chain. In addition, a plurality of alkylene oxide groups — (R ² O) — may be the same or different.

The polyether monool (A1) can be obtained by adding a cyclic ether such as alkylene oxide to the compound having one hydroxyl group (R ¹ OH) as an initiator.

Examples of the compound represented by R ¹ OH used as an initiator include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, 2-ethylhexyl alcohol, phenol, benzyl alcohol, N-methyl- Examples thereof include N-ethylamino alcohol and N, N-diethylamino alcohol.

  Examples of the alkylene oxide added to the initiator include ethylene oxide, propylene oxide, and butylene oxide. Preferably, propylene oxide is 80 mol% or more of the total alkylene oxide.

  The polyether monool (A2) used in the present invention has a number average molecular weight of 150 to 10,000, preferably 150 to 5,000. When the number average molecular weight of the polyether monool (A2) is excessively small, the effect of improving uniform mixing with a foaming agent (particularly, a foaming agent comprising hydrofluorocarbons and / or water) should be sufficiently exerted. May not be possible. On the other hand, when the number average molecular weight of the polyether monool (A2) is excessive, the resulting polyisocyanate composition has a high viscosity, which may cause a decrease in workability.

One example of a preferred compound as a polyether monol (A2), having an alkoxy group having 4 to 12 carbon atoms as terminal groups ^(R 1 O-), repeating units - as ^[(R 2 O) n-] Poly (oxyethylene) monool, poly (oxypropylene) monool, poly (oxyethylene-oxypropylene) copolymer mono having an oxyethylene group and / or an oxypropylene group and having a number average molecular weight of 500 to 1,000 All can be mentioned. In a more preferred embodiment, the ratio of oxypropylene to oxyethylene is oxypropylene / oxyethylene = 0.5 or more.

  In the polyisocyanate composition of the present invention, the polyether monool (A2) having a number average molecular weight of 150 to 10,000 may be present in a form reacted with a part of the isocyanate group in the polymeric MDI (A1). It may be present in a uniformly mixed form without reacting with the isocyanate group.

<Silicone-based foam stabilizer (A3)>
The silicone-based foam stabilizer (A3) that may contain a hydroxyl group constituting the polyisocyanate composition of the present invention is not particularly limited, and is conventionally known as a foam stabilizer for rigid polyurethane foams. (Dimethylpolysiloxane and polysiloxane-polyether copolymer) can all be used.

  Examples of the silicone foam stabilizer (A3) include known silicone surfactants such as L-5340, L-5420, L-5421, L-5740, L-580, and SZ manufactured by Toray Dow Corning. -1,142, SZ-1642, SZ-1605, SZ-1649, SZ-1919, SH-190, SH-192, SH-193, SF-2945F, SF-2940F, SF-2936F, SF-2238F, SRX-294A F-305, F-341, F-343, F-374, F-345, F-348 made by Shin-Etsu Chemical, B-8404, B-8407, B-8465, B-8444 made by Goldschmidt, B-8467, B-8433, B-8466, B-8870, B-8450, B-8460, etc. are mentioned.

  In the present invention, it is preferable to use a polysiloxane-polyether copolymer containing a hydroxyl group (hereinafter referred to as “hydroxyl group-containing silicone”) as a part or all of the silicone foam stabilizer (A3). In this case, according to the polyisocyanate composition of the present invention containing a hydroxyl group-containing silicone-based foam stabilizer, uniform mixing with a foaming agent (particularly, a phase with a foaming agent comprising hydrofluorocarbons and / or water). The solubility and dispersibility of the foaming agent in the composition can be further improved.

  The hydroxyl group-containing silicone is a block copolymer having a dimethylpolysiloxane structure and a polyoxyalkylene structure (polyether structure), and is a compound having a hydroxyl group in the molecular structure.

  The average number of functional groups (average number of hydroxyl groups in one molecule) of the hydroxyl group-containing silicone is preferably 1 to 10, more preferably 1 to 5, and particularly preferably 1 to 2. When the average number of functional groups is too large, the resulting polyisocyanate composition has a high viscosity, and the workability during foaming tends to decrease.

  The number average molecular weight of the hydroxyl group-containing silicone is preferably 500 to 20,000, and more preferably 1,000 to 18,000. Those having an excessive number average molecular weight have high viscosity and poor handleability.

  The hydroxyl value of the hydroxyl group-containing silicone is preferably 3 to 300 mgKOH / g, more preferably 5 to 150 mgKOH / g. When the hydroxyl value is excessively low, the viscosity is high and the handleability is poor, and the formed foam does not have sufficient strength. On the other hand, when the hydroxyl value is excessive, the resulting polyisocyanate composition cannot sufficiently improve the uniform mixing property with the foaming agent.

  In addition, although the silicone type foam stabilizer (A3) which may contain a hydroxyl group is used in the range of 0.05 to 2.0% by mass when the polyisocyanate composition of the present invention is 100% by mass, Preferably it is in the range of 0.1 to 1.0% by mass, and above all, it has the liquid viscosity of the polyisocyanate composition of the present invention (avoids increase in viscosity due to excessive introduction), and uniform mixing with hydrofluorocarbons ( From the viewpoint of having compatibility (this effect cannot be obtained by slight introduction), it is particularly preferably used in the range of 0.2 to 1.0% by mass.

<Compound (A4) Represented by General Formula (1) Shown below>
As the compound (A4) represented by the following general formula (1) constituting the polyisocyanate composition of the present invention, for example, all conventionally known compounds called dialkyl glycol ethers can be used.

  In the present invention, at the time of forming the rigid polyurethane foam, the general formula (1) is used from the viewpoint of imparting more uniform mixing property (compatibility) with the polyol or water to the polyisocyanate composition of the present invention. ) As the compound (A4) represented by (), mention may be made of diethylene glycol dimethyl ether (DMDG), triethylene glycol dimethyl ether (DMTG), diethylene glycol diethyl ether (DEDG), diethylene glycol dibutyl ether (DBDG), dipropylene glycol dimethyl ether (DMFDG) and the like. These may be used alone or in combination of two or more.

In the present invention, as the compound (A4) represented by the general formula (1), the boiling point and the flash point are both relatively high, the viscosity is low, and the compatibility with water is good. In view of the above, it is preferable to select and use diethylene glycol diethyl ether (DEDG).

  In addition, although the compound (A4) represented by the said General formula (1) is used in 0.5-5.0 mass% when the polyisocyanate composition of this invention is 100 mass%, it is 0.00. It is preferably used in the range of 5 to 3.0% by mass, and among them, the desired dimensional stability is ensured for the obtained rigid polyurethane foam (excessive introduction deteriorates the dimensional stability). From the viewpoint of having excellent adhesiveness under a low temperature atmosphere such as 5 ° C. (this effect cannot be obtained if the introduction amount is small), it is particularly used in the range of 1.0 to 2.5% by mass. preferable.

<Other isocyanate compounds>
In the polyisocyanate composition of the present invention, the above-mentioned polymeric MDI (A1) is essential, but if necessary, the polyisocyanate composition of the present invention is an isocyanate compound other than the essential isocyanate compound (hereinafter “others”). Abbreviated as “isocyanate compound”).

  As other isocyanate compounds, urethanized products obtained by reacting polymeric MDI (or only MDI) and active hydrogen group-containing compounds (the above-mentioned polyether monool (A2) having a number average molecular weight of 150 to 10,000) and Except for those in the form in which a part of the isocyanate group in the polymeric MDI (A1) is reacted), urea compound, allophanate compound, biuret compound, carbodiimide compound, uretoniminate compound, uretdione compound, isocyanurate compound; 2,4 -Tolylene diisocyanate, 2,6-tolylene diisocyanate, xylene-1,4-diisocyanate, xylene-1,3-diisocyanate, tetramethylxylene diisocyanate, m-phenylene diisocyanate, p-phenylene diiso Aromatic diisocyanates such as anate; Aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, 3-methyl-1,5-pentane diisocyanate, lysine diisocyanate; Isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated And alicyclic diisocyanates such as diphenylmethane diisocyanate. In addition, urethanized products, urea compounds, allophanate compounds, biuret compounds, carbodiimide compounds, uretoniminate compounds, uretdione compounds, isocyanurate compounds, etc. obtained by reacting these polymeric substances and these isocyanates with active hydrogen group-containing compounds. It can also be used. These isocyanate compounds can be used alone or in combination of two or more.

<Optional component>
The polyisocyanate composition of the present invention may contain various optional components as long as the effect is not impaired. As such optional components, all conventionally known substances (such as additives) can be used as those contained in the polyisocyanate composition for producing a rigid polyurethane foam.

<Polyisocyanate composition>
As isocyanate group content in the polyisocyanate composition of this invention, it is preferable that it is 28.0-31.5 mass%, More preferably, it is 28.5-31.0 mass%, Especially, the polyisocyanate of this invention The rigid polyurethane foam obtained using the composition can have the desired mechanical properties, and the viscosity of the polyisocyanate composition of the present invention is suitable for the production of a rigid polyurethane foam (for example, spraying operation during spray foaming). From the viewpoint of becoming, it is particularly preferably 29.0 to 31.0% by mass.

  As a viscosity (25 degreeC) of the polyisocyanate composition of this invention, it is preferable that it is 50-500 mPa * s, More preferably, it is 70-300 mPa * s, especially manufacture of a rigid polyurethane foam (for example, spraying at the time of spray foaming) From the standpoint of suitability for work, it is particularly preferably 80 to 150 mPa · s.

  Since the polyisocyanate composition of the present invention is excellent in homogeneous mixing with hydrofluorocarbons and water (compatibility / dispersibility of hydrofluorocarbons and water in the composition), a foaming formulation using these as a foaming agent It is preferably used to produce rigid polyurethane foams according to

  In particular, the polyisocyanate composition of the present invention is sprayed in a low temperature environment (especially at a temperature of -5 ° C.) which cannot be applied from the viewpoint of adhesiveness with a conventionally known polyisocyanate composition (spray application). And a rigid polyurethane foam having good adhesion to the adherend can be formed.

  Here, the adherend to which the polyisocyanate composition of the present invention is applied is not particularly limited, and examples thereof include woods, concretes, various metals, papers, stones, various plastics, and ceramics. , Glass and various rubbers.

  In addition, as a use aspect (construction method) of the polyisocyanate composition of this invention, of course, it is not limited to spray construction.

<Method for producing rigid polyurethane foam>
The production method of the present invention comprises a rigid polyurethane in which the polyisocyanate composition of the present invention is reacted with a polyol (B) in the presence of a foaming agent (C), a catalyst (D) and a foam stabilizer (E). A method for producing a foam, wherein the polyisocyanate composition comprises:
(A1) Diphenylmethane diisocyanate isomer mixture (a1d) is 20 to 80% by mass, triphenyl or higher diphenylmethane diisocyanate polynuclear condensate (a1p) is 80 to 20% by mass (provided that (a1d) + (a1p) = ( Polymeric MDI which is 100% by weight as A1)
(A2) a polyether monool having a number average molecular weight of 150 to 10,000,
(A3) a polyisocyanate composition obtained by reacting and mixing a silicone-based foam stabilizer that may contain a hydroxyl group, and (A4) a compound represented by the following general formula (1),
(A1) = 98.95-88.0% by mass,
(A2) = 0.5-5% by mass,
(A3) = 0.05-2.0 mass% and (A4) = 0.5-5.0 mass%
(However, (A1) + (A2) + (A3) + (A4) = 100% by mass as the whole composition)
In addition, the foaming agent (C) is characterized in that hydrofluorocarbon and / or water is used.

<Polyol (B)>
The “polyol (B)” used in the production method of the present invention is not particularly limited, and examples thereof include conventionally known polyester polyols, polyether polyols, and polycarbonate polyols. In consideration of the strength of the rigid polyurethane foam to be formed, a low molecular polyol, a low molecular polyamine, a low molecular amino alcohol, or the like may be used in combination.

  As the polyol (B) used in the production method of the present invention, at least one of the following three types of polyols [polyols (b1) to (b3)] is preferably used, and two or more types may be used. Further preferred.

  When only one of polyol (b1) and polyol (b3) is used, the formed rigid polyurethane foam may not have sufficient mechanical strength. Moreover, the polyol (B) consisting only of the polyol (b2) has an excessive viscosity and tends to be inferior in workability.

[Polyol (b1)]
One or more amine compounds such as monoethanolamine, diethanolamine, alkanolamines such as triethanolamine, tolylenediamine, ethylenediamine, diethylenetriamine, ammonia, aniline, xylylenediamine, polyamines such as diaminodiphenylmethane, etc. A polyether polyol having a hydroxyl value of 50 to 1,000 mgKOH / g, preferably 100 to 900 mgKOH / g, obtained by addition reaction of alkylene oxides such as ethylene oxide and propylene oxide using the mixture as an initiator. Furthermore, a polyhydric alcohol used for obtaining the polyol (b2) and the polyol (b3) can be used in combination as an initiator.

[Polyol (b2)]
(1) Ethylene glycol, propanediol, butanediol, diethylene glycol, dipropylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, glycerin , A mixture of one or more polyhydric alcohols such as trimethylolpropane and pentaerythritol, and adipic acid, malonic acid, fumaric acid, succinic acid, tartaric acid, oxalic acid, phthalic anhydride, isophthalic acid, terephthalic acid , 1,4-cyclohexanedicarboxylic acid and the like, and a known method using one or a mixture of two or more compounds having at least two carboxyl groups (or groups derived from carboxyl groups) By Obtained by fabricating Te, hydroxyl value 50~800mgKOH / g, polyester polyols preferably 100~700mgKOH / g. (2) A polyester polyol obtained by ring-opening polymerization of lactones (for example, ε-caprolactone).
(3) A recovered polyester obtained by decomposing a polyester polyol and a polyester molded product.

[Polyol (b3)]
Ethylene glycol, propanediol, butanediol, diethylene glycol, dipropylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, glycerin, trimethylol Obtained by addition reaction of alkylene oxides such as ethylene oxide and propylene oxide using a polyhydric alcohol having 2 to 6, preferably 2 to 5 hydroxyl groups in one molecule such as propane and pentaerythritol as an initiator. A polyether polyol having a hydroxyl value of 50 to 1,000 mg KOH / g, preferably 100 to 900 mg KOH / g.

  In each of the polyols (b1) to (b3), when the hydroxyl value is not less than a certain value (lower limit value), sufficient mechanical strength can be imparted to the formed rigid polyurethane foam. Moreover, embrittlement of the hard polyurethane foam formed can be suppressed because a hydroxyl value is below a fixed value (upper limit).

  The average number of functional groups of the polyol (b1) is preferably 2 to 8, more preferably 3 to 6.

  The average number of functional groups of the polyol (b2) is preferably 2 to 4, more preferably 2 to 3.

  The average number of functional groups of the polyol (b3) is preferably 3 to 6, more preferably 3 to 5.

  In each of the polyols (b1) to (b3), when the average number of functional groups is a certain number (lower limit) or more, sufficient mechanical strength can be imparted to the formed rigid polyurethane foam. Moreover, embrittlement of the rigid polyurethane foam formed can be suppressed because an average functional group number is below a fixed number (upper limit).

  When using a polyol (b1), it is preferable that the ratio of the polyol (b1) to a polyol (B) is 40-70 mass%.

  When using a polyol (b2), it is preferable that the ratio of the polyol (b2) to a polyol (B) is 10-90 mass%.

  When using a polyol (b3), it is preferable that the ratio of the polyol (b3) to a polyol (B) is 10-70 mass%.

  The total proportion of polyol (b1), polyol (b2), and polyol (b3) in the polyol (B) is preferably 80% by mass or more.

  When the content ratio of the polyol (b1) is excessive, the activity becomes too high, and there is a risk of causing molding defects such as voids.

  When the content ratio of the polyol (b2) is excessive, the viscosity of the polyol (B) increases, and the liquid flowability and filling property of the foam tend to deteriorate.

  When the content ratio of the polyol (b3) is excessive, the mechanical strength of the formed rigid polyurethane foam tends to decrease.

  Suitable polyols other than polyols (b1) to (b3) constituting the polyol (B) (hereinafter abbreviated as other polyols) are preferably ethylene glycol, diethylene glycol, and polypropylene glycol having a hydroxyl value of 50 to 150 mgKOH / g. Can be mentioned.

  By using at least one selected from ethylene glycol, diethylene glycol, and polypropylene glycol having a hydroxyl value of 50 to 150 mgKOH / g, the viscosity of the polyol (B) can be lowered.

  Moreover, you may use a polymer polyol as another polyol which comprises a polyol (B). This polymer polyol is based on the above-described polyether polyol or polyester polyol, and is obtained by introducing a styrene or acrylonitrile vinyl polymer or a polymer obtained from an active hydrogen group-containing compound and polyisocyanate as graft polymerization or filler. The polymer content in the polymer polyol is preferably 1 to 20% by mass.

  The viscosity (25 ° C.) of the polyol (B) is preferably 2,000 mPa · s or less, more preferably 100 to 1,800 mPa · s. When the viscosity exceeds the upper limit, workability particularly in winter is reduced.

<Foaming agent (C)>
In the production method of the present invention, hydrofluorocarbon and / or water is used as the foaming agent (C).

  As addition amount of a foaming agent (C), when using hydrofluorocarbons, such as HFC-245fa, HFC-365mfc, and HFC-134a, it is 1-50 mass% with respect to a polyol (B).

  Moreover, the addition amount of water in the case where hydrofluorocarbon and water are used in combination is 0.5 to 5.0% by mass with respect to the polyol (B).

  Moreover, in the complete water foaming formulation which uses only water, the addition amount of water is 2.0-20.0 mass% with respect to a polyol (B).

<Catalyst (D)>
As the “catalyst (D)” used in the production method of the present invention, a known catalyst usually used for urethane foaming can be used. For example, as a urethanization catalyst, N-methylimidazole, trimethylaminoethylpiperazine, tripropylamine, tetramethylhexamethylenediamine, triethylenediamine, triethylamine, N-methylmorpholine, dimethylcyclohexylamine, dibutyltin diacetate, dibutyltin dilaurate, etc. And metal complex compounds such as acetylacetone metal salts. Trimerization catalysts include 2,4,6-tris (dimethylaminomethyl) phenol, triazines such as 1,3,5-tris (dimethylaminopropyl) hexahydro-s-triazine, 2,4-bis (dimethylamino) Methyl) phenol, amine compounds such as potassium 2-ethylhexanoate, sodium 2-ethylhexanoate, potassium acetate, sodium acetate, 2-ethylaziridine and the like, and quaternary compounds such as tertiary amine carboxylates Examples include ammonium compounds, lead compounds such as diazabicycloundecene, lead naphthenate and lead octylate, alcoholate compounds such as sodium methoxide, phenolate compounds such as potassium phenoxide, and the like. These catalysts can be used alone or in combination of two or more.

  The amount of the catalyst (D) used is suitably an amount of 0.01 to 15% by mass with respect to the polyol (B).

<Foam stabilizer (E)>
The foam stabilizer (E) used in the production method of the present invention is not particularly limited as the aforementioned silicone foam stabilizer (A3), and is conventionally known as a foam stabilizer for rigid polyurethane foams. Any of those (dimethylpolysiloxane and polysiloxane-polyether copolymer) can be used. Specific examples include those listed in the aforementioned silicone foam stabilizer (A3). The amount of the foam stabilizer (E) used is suitably 0.1 to 5% by mass relative to the polyol (B). The foam stabilizer (E) used in the production method of the present invention is used as the silicone foam stabilizer (A3) described above in order to provide the performance desired for the rigid polyurethane foam obtained by the present invention. The same thing as a thing may be used, and another thing may be used.

  In the production method of the present invention, an additive can be used (the polyisocyanate mixture (A) and the polyol (B) are reacted in the presence of the additive). Examples of the additives include plasticizers, fillers, colorants, flame retardants, organic or inorganic fillers, antioxidants, ultraviolet absorbers, plasticizers, pigments / dyes, antibacterial agents / antifungal agents, and the like. . In the present invention, it is preferable to use a flame retardant. Examples of the flame retardant include phosphate esters such as triethyl phosphate and tris (β-chloropropyl) phosphate, and phosphate compounds such as phosphite esters such as ethyl phosphite and diethyl phosphite.

  In the production method of the present invention, a multicomponent system having three or more components may be used. However, for the purpose of simplifying the apparatus, the “I liquid” containing the polyisocyanate composition of the present invention as a main component and a polyol ( It is preferable to use a two-component system composed of “R liquid” containing B) as a main component.

  Hereinafter, an example of a preferable specific production method in the case of a two-component system will be shown.

(1) The polyisocyanate composition of the present invention is referred to as “liquid I”, and the polyol (B) is referred to as “liquid R”.

(2) The foaming agent (C), the catalyst (D), the foam stabilizer (E) and the additive (optional component) are mixed in the “I liquid” and / or “R liquid”. The foaming agent (C), catalyst (D) and foam stabilizer (E) are preferably mixed in the “R liquid”. Moreover, the silicone type foam stabilizer (A2) contained in "I liquid" from the beginning is handled as what comprises a foam stabilizer (E) in a subsequent process.

(3) "I liquid" and "R liquid" are mixed, and the polyisocyanate composition of the present invention and the polyol (B) are mixed with the blowing agent (C), the catalyst (D) and The reaction is carried out in the presence of the foam stabilizer (E), and the reaction system is foamed and cured.

  There is no particular limitation on the mixing device for “I liquid” and “R liquid”. For example, a small mixer, a low pressure or high pressure foaming machine for injection foaming used for producing general urethane foam. A low-pressure or high-pressure foaming machine for slab foaming, a low-pressure or high-pressure foaming machine for continuous lines, a spray foaming machine for spraying work, or the like can be used. The temperature of the “I liquid” and “R liquid” to be mixed is preferably adjusted to 15 to 50 ° C.

  The rigid polyurethane foam obtained by the production method of the present invention has a chemical bond such as a urethane bond or a urea bond (so-called urethane foam). Depending on the production conditions, an isocyanurate group can be generated at the time of foaming, and the isocyanurate-modified polyurethane foam (so-called isocyanurate foam) thus obtained is also included in the “rigid polyurethane foam”. The isocyanurate group is generated by trimerizing an isocyanate group with a trimerization catalyst, and can improve mechanical strength, heat resistance, and the like.

  In the production method of the present invention, the preferred isocyanate index [(number of moles of all isocyanate groups in polyisocyanate composition / number of moles of all active hydrogen groups in polyol (B)) × 100] is the case of so-called urethane foam. It is preferable that it is 50-140, More preferably, it is 70-130. Moreover, in the case of what is called isocyanurate foam formed using a trimerization catalyst, it is preferable that it is 140-800, More preferably, it is 150-500. When the isocyanate index is less than 50 in the case of urethane foam and less than 140 in the case of isocyanurate foam, the obtained foam may not have sufficient strength and tends to shrink. On the other hand, if it exceeds 140 in the case of urethane foam and exceeds 800 in the case of isocyanurate foam, the brittleness of the resulting foam tends to increase and the adhesiveness tends to decrease.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not construed as being limited by these examples. In the following, unless otherwise specified, “%” and “part” indicate “% by mass” and “part by mass”, respectively.

<Synthesis of organic polyisocyanate composition>
Example 1
In accordance with the formulation shown in Table 1 below, a reactor equipped with a stirrer, a cooling pipe, a nitrogen introduction pipe, and a thermometer: In a 100 kg reactor, 84.7 kg of “isocyanate B” and 11.6 kg of “isocyanate D” were added. Each was charged and heated to 60 ° C. with stirring to obtain “Polymeric MDI (A1)”. Next, 2.0 kg of “A2-1” as the polyether monool (A2), 0.2 kg of “A3-2” as the silicone foam stabilizer (A3), and “A4” as the dialkyl glycol ether (A4) -1 "and 1.5 kg were respectively charged into the reactor. After completion of the preparation, the mixture was reacted at 60 ° C. for 2 hours with stirring to obtain a polyisocyanate composition “NCO-1” of the present invention. This polyisocyanate composition “NCO-1” had an isocyanate group content (hereinafter abbreviated as “NCO content” as necessary) of 29.8% and a viscosity (25 ° C.) of 105 mPa · s.

Examples 2-12, Comparative Examples 1-15
According to the formulations shown in Table 1 and Table 2 below, isocyanates A to D, polyether monool (A2) “A2-1” to “A2-4”, silicone foam stabilizers “A3-1” or “A3” -2 "and each of" A4-1 "to" A4-5 "as dialkyl glycol ether (A4) was used in the same manner as in Example 1, except that the polyisocyanate composition" NCO- 2 ”to“ NCO-12 ”and polyisocyanate compositions“ NCO-13 ”to“ NCO-27 ”as comparative examples were prepared. The isocyanate content and viscosity (25 degreeC) of the obtained polyisocyanate composition are combined with Table 1-Table 4, and are shown.

<Uniform mixing with hydrofluorocarbons and water>
About each of polyisocyanate composition "NCO-1"-"NCO-27" obtained by said Examples 1-12 and Comparative Examples 1-15, according to the following method, uniform mixing property with hydrofluorocarbons and water Evaluated. The results are also shown in Tables 1 to 4.

(Evaluation method for uniform mixing with hydrofluorocarbons)
A polyisocyanate composition (50 g) and hydrofluorocarbon (HFC-365mfc) (20 g) were charged into a lab mixer, mixed at 7,000 rpm for 3 seconds, and the appearance of the mixture was visually observed immediately after the operation and after 30 minutes. The evaluation was based on the following criteria.

(Evaluation method for uniform mixing with water)
A polyisocyanate (composition) 50 g and purified water 5 g were charged into a lab mixer, mixed at 7,000 rpm for 3 seconds, and the appearance of the mixture was observed visually and immediately after 30 minutes. Based on the evaluation.

(Evaluation criteria)
“◎”: A homogeneous emulsified state was obtained, and this state was maintained even after 30 minutes.
“◯”: An emulsified state was obtained, but phase separation occurred after 30 minutes.
“×”: Phase separation occurred immediately after the operation.

<Liquid storage stability of polyisocyanate composition under low temperature atmosphere>
For each of the polyisocyanate compositions “NCO-1” to “NCO-27” obtained in Examples 1 to 12 and Comparative Examples 1 to 4, 200 g was charged into a 200 ml glass sample bottle and sealed with a lid. After that, it was allowed to stand for 90 days in an atmosphere of −5 ° C., −10 ° C., and −20 ° C. The appearance after 90 days elapsed was visually observed and evaluated based on the following criteria. The results are also shown in Tables 1 to 4.

(Evaluation criteria)
“◯”: No crystal precipitation or liquid phase separation is observed.
“X”: Crystal precipitation, liquid phase separation, or turbidity of the liquid, which seems to be a precursor of these, is observed.
The polyisocyanate compositions “NCO-1” to “NCO-27” at the start of measurement are all determined to be “◯”.

  The details of the compounds (components or reaction raw materials) in Tables 1 to 4 are as follows. The unit of these usage amounts is “parts”.

<Isocyanate A>
(I) MPC peak area ratio by GPC = 40% (polymeric MDI)
(Ii) 4,4′-MDI ratio in MDI = 99% (measured by GC)
(Iii) Isocyanate content = 30.8%
(Iv) Average number of functional groups = 2.3
(V) Acidity = 0.01%
<Isocyanate B>
(I) MPC peak area ratio by GPC = 37% (polymeric MDI)
(Ii) 4,4′-MDI ratio in MDI = 89% (measured by GC)
(Iii) Isocyanate content = 30.7%
(Iv) Average number of functional groups = 2.3
(V) Acidity = 0.01%
<Isocyanate C>
(I) MDI (binuclear body)
(Ii) 4,4′-MDI ratio = 99% (measured by GC)
(Iii) Acidity = 0.001%
<Isocyanate D>
(I) MDI (binuclear body)
(Ii) 4,4′-MDI ratio = 82% (measured by GC)
(Iii) Acidity = 0.001%
<Polyether monool (A2-1)>
(I) Initiator = 2-ethylhexanol (ii) Number average molecular weight = 800
(Iii) PO (oxypropylene) / EO (oxyethylene) = 100/0 (mass ratio)
<Polyether monool (A2-2)>
(I) Initiator = 2-ethylhexanol (ii) Number average molecular weight = 800
(Iii) PO (oxypropylene) / EO (oxyethylene) = 90/10 (mass ratio)
<Polyether monool (A2-3)>
(I) initiator = phenol (ii) number average molecular weight = 800
(Iii) PO (oxypropylene) / EO (oxyethylene) = 100/0 (mass ratio)
<Polyether monool (A2-4)>
(I) Initiator = methanol (ii) Number average molecular weight = 700
(Iii) PO (oxypropylene) / EO (oxyethylene) = 0/100 (mass ratio)
<Silicone-based foam stabilizer (A2-1)>
Polysiloxane-polyether copolymer "L-5340" (manufactured by Toray Dow Corning Silicone)
Hydroxyl value = 0
<Silicone-based foam stabilizer (A2-2)>
Polysiloxane-polyether copolymer “B-8460” (manufactured by Goldschmidt)
Hydroxyl value = 120
<Dialkyl glycol ether (A3-1)>
Diethyl diglycol (diethylene glycol diethyl ether) “DEDG” (manufactured by Nippon Emulsifier Co., Ltd.)
<Dialkyl glycol ether (A3-2)>
Dimethyltriglycol (triethylene glycol dimethyl ether) “DMTG” (manufactured by Nippon Emulsifier Co., Ltd.)
<Dialkyl glycol ether (A3-3)>
Diethylene glycol dimethyl ether “DMDG” (manufactured by Nippon Emulsifier Co., Ltd.)
<Dialkyl glycol ether (A3-4)>
Diethylene glycol dibutyl ether “DBDG” (manufactured by Nippon Emulsifier Co., Ltd.)
<Dialkyl glycol ether (A3-5)>
Dipropylene glycol dimethyl ether “DMFDG” (manufactured by Nippon Emulsifier Co., Ltd.)
<Specific polyester polyol>
(I) Sulfonato group (sodium sulfonate residue) -containing adipate obtained by reacting dimethyl 5-sodium sulfoisophthalate, adipic acid and 1,6-hexanediol according to a conventional method (ester reaction and transesterification reaction) Polyester polyol.
(Ii) Number average molecular weight = 1,000, content ratio of sulfonate group = 0.4 mmol / g

<Preparation Examples 1-2>
According to the formulation shown in Table 3 below, polyol components “OH-1” and “OH-2” were prepared by uniformly mixing the components.

  Details of the compounds (components) in Table 5 are as follows. The unit of these usage amounts is “parts”.

<Polyol (B-1)>
Polyester polyol “terol 693” having a hydroxyl value of 250 using phthalic anhydride / diethylene glycol as a raw material (manufactured by OXID, USA)
<Polyol (B-2)>
Polyester polyol “terol 250” having a hydroxyl value of 250 using phthalic anhydride / diethylene glycol as a raw material (manufactured by OXID, USA)
<Polyol (B-3)>
Mannich polyether polyol “DK polyol 3776” having a hydroxyl value of 350 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
<Polyol (B-4)>
Mannich polyether polyol “DK polyol 3773” having a hydroxyl value of 450 (Daiichi Kogyo Seiyaku Co., Ltd.)
<Foaming agent (C-1)>
HFC-245fa (manufactured by Central Glass Co., Ltd.)
<Foaming agent (C-2)>
HFC-365mfc (manufactured by Solvay)
<Foaming agent (C-3)>
Purified water <Catalyst (D-1)>
Trimerization catalyst “DABCO K15” (manufactured by Air Products)
<Catalyst (D-2)>
Lead octylate "Nikka Octix Lead" (Nippon Chemical Industry Co., Ltd.)
<Foam stabilizer (E-1)>
Polysiloxane-polyether copolymer “B-8460” (manufactured by Goldschmidt)
<Flame Retardant (F-1)>
Tris (β-chloropropyl) phosphate “Philol PCF” (manufactured by Akzo Nobel)

<Formation (production) of rigid polyurethane foam>
Examples 13 to 25, Comparative Examples 16 to 30
In accordance with the combinations shown in Tables 6 to 9 below, a mixed liquid (mixed volume ratio = 100: 100) of the polyisocyanate composition (liquid A) and the polyol composition (liquid B) is used as an adherend ( The polyisocyanate mixture (A), the polyol (B), the foaming agent (C), the catalyst (D), and the foam regulating agent are sprayed onto a veneer plate (1000 mm × 1000 mm) to which 50 mm × 50 mm) is attached. The reaction was carried out in the presence of the agent (E) and the like, and a rigid polyurethane foam was formed on the entire surface of the veneer plate (1000 mm × 1000 mm) to which the adherend was attached. In addition, cream time and rise time were measured as reactivity during the formation. The foam core density was measured after curing in a −5 ° C. atmosphere while standing for 24 hours after formation.
Here, the blowing and foaming conditions are as follows.
-Foaming machine: Gasmer spraying foaming machine "FF-1600 type"
-Temperature of adherend: -5 ° C
・ Primary heater temperature: 45 ℃
-Foam thickness: 30-40mm

<Foam shrinkage at normal temperature (rate of volume change due to standing)>
According to Examples 13 to 25 and Comparative Examples 16 to 30, samples of length = 100 mm, width = 100 mm, height (foaming direction) = 25 mm were obtained from each of the rigid polyurethane foams formed on the plywood (1000 mm × 1000 mm). Take this sample and let it stand at 25 ° C for 24 hours, then measure the vertical, horizontal, and height dimensions again to measure the volume change rate of the foam and evaluate it based on the following criteria: did. The results are also shown in Tables 6 to 9.

(Evaluation criteria)
“◎”: Volume change rate = 2% or less “◯”: Volume change rate = 2% or more and less than 5% “×”: Volume change rate = 5% or more

<Adhesiveness to adherend>
For each of the rigid polyurethane foams formed on the adherend (50 mm × 50 mm drawing paper) according to Examples 13 to 25 and Comparative Examples 16 to 30, after being left in a temperature environment of −5 ° C. for 2 hours, A peeling test was performed to measure the adhesive strength to the adherend (drawing paper). The results are also shown in Tables 6 to 9.

  The polyisocyanate composition of the present invention is used for various heat insulating materials such as boards, panels, refrigerators, baskets, doors, shutters, sashes, concrete houses, bathtubs, cryogenic tank equipment, refrigerated warehouses, pipe covers, anti-condensation, slabs, etc. Applicable.

The polyisocyanate composition of the present invention is particularly suitable for the application of spraying (spray foaming) to various adherends, in particular, spraying (spray foaming) to various adherends in cold regions such as temperatures of -5 ° C. ing.

Claims (4)

(A1) 20 to 80% by mass of the diphenylmethane diisocyanate isomer mixture (a1d) is 80 to 20%, and the triphenyl or higher diphenylmethane diisocyanate polynuclear condensate (a1p) is 80 to 20%.
Polymeric MDI that is mass% (however, (a1d) + (a1p) = 100 mass% as (A1)),
(A2) a polyether monool having a number average molecular weight of 150 to 10,000,
(A3) A silicone-based foam stabilizer that may contain a hydroxyl group, and (A4) a compound represented by the following general formula (1)

A polyisocyanate composition obtained by reacting and mixing
(A1) = 98.95-88.0% by mass,
(A2) = 0.5-5% by mass,
(A3) = 0.05-2.0 mass% and (A4) = 0.5-5.0 mass%
(However, (A1) + (A2) + (A3) + (A4) = 100 mass% as the whole composition) A polyisocyanate composition for producing rigid polyurethane foam, (A1) 4,4′-diphenylmethane diisocyanate (4,4′-MDI) is 60 to 95% by mass, diphenylmethane diisocyanate isomers other than 4,4′-diphenylmethane diisocyanate (isomer MDI) is 5 to 40% by mass. 20 to 80% by mass of a diphenylmethane diisocyanate isomer mixture (a1d) comprising 80 to 20% by mass of a trinuclear or higher diphenylmethane diisocyanate polynuclear condensate (a1p) (provided that (a1d) + (a1p) = (A1) ) 100% by weight) polymeric MDI,
(A2) A polyisocyanate composition obtained by reacting and mixing a polyether monool having a number average molecular weight of 150 to 10,000 (A3) a hydroxyl group-containing silicone-based foam stabilizer and (A4) diethylene glycol dimethyl ether,
(A1) = 98.95-88.0% by mass,
(A2) = 0.5-5% by mass,
(A3) = 0.05-2.0 mass%, and (A4) = 0.5-5.0 mass%,
(However, (A1) + (A2) + (A3) + (A4) = 100% by mass as the whole composition)
A polyisocyanate composition for producing rigid polyurethane foam, characterized in that   A rigid polyurethane foam obtained by reacting the polyisocyanate composition according to claim 1 or 2 with a polyol (B) in the presence of a foaming agent (C), a catalyst (D) and a foam stabilizer (E). A method for producing a rigid polyurethane foam, characterized in that hydrofluorocarbon and / or water is used as the foaming agent (C). 4. The method for producing a rigid polyurethane foam according to claim 3, wherein the rigid polyurethane foam is formed on the adherend by a spray method.