JP2001316443A - Method for manufacturing hard polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hard polyurethane foam excellent in storage stability, applicability, foam strength, dimensional stability and adhesive properties and to provide a recipe for decreasing HCFC-141b. SOLUTION: A polyol (A), selected among (a1) a polyether polyol having an average functionality of 2-8 and a hydroxyl value of 250-750 mgKOH/g, (a2) a polyester polyol having an average functionality of 2-4 and a hydroxyl value of 150-350 mgKOH/g and (a3) a polyether polyol having an average functionality of 3-6 and a hydroxyl value of 250-750 mgKOH/g, is reacted with a polisocyanate (B) containing an isocyanate group-terminated prepolyme in the presence of a blowing agent (C), a catalyst (D) and a foam stabilizer (E). As the blowing agent (C), water is preferably employed. This method is suitable particularly for manufacturing a water-blown spray foam used for works of a spraying a heat insulating material or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a rigid polyurethane foam used for spraying heat insulating material. More specifically, the present invention relates to a method for producing a rigid polyurethane foam, which uses a specific polyol and a specific polyisocyanate, uses a non-fluorocarbon-based blowing agent as a blowing agent, and is particularly suitable for a water-foaming spray foam. In the present invention, the “rigid polyurethane foam” is a concept including an isocyanurate-modified polyurethane foam unless otherwise specified.

[0002]

2. Description of the Related Art Rigid polyurethane foam has heat insulating properties,
Because of its excellent dimensional stability, workability, etc., it is widely used as a heat insulating material for refrigerators, freezer warehouses, building materials, etc., and for spray applications. When producing a rigid polyurethane foam, 1,1-dichloro-1 is used as a foaming agent.
-Fluoroethane (hereinafter abbreviated as HCFC-141b) has been used.

In recent years, (hydro) chlorofluorocarbons have been regulated to protect the ozone layer on the earth. This regulation includes HCFC-141b which is used as a foaming agent for rigid polyurethane foam. Therefore, a foaming formulation for reducing the amount of HCFC-141b used, that is, 1,1,1,3,3-pentafluoropropane (hereinafter abbreviated as HFC-245fa), 1,1,1,3,3- Development of a foaming formulation using hydrofluorocarbons such as pentafluorobutane (hereinafter abbreviated as HFC-356mfc) and hydrocarbon-based blowing agents (eg, normal pentane, cyclopentane, hexane, etc.) has led to the development of the ozone layer of the earth. It is an important issue for protection. Further, a foaming formulation using water as a foaming agent (hereinafter abbreviated as a water foaming formulation) has been proposed.

However, the aforementioned HCFC-141b
In the case of a reduced formulation or a water-foaming formulation, the obtained rigid polyurethane foam is more likely to have reduced foam strength, poor dimensional stability, and poor adhesion to adherends as compared to conventional rigid polyurethane foam. There are disadvantages, such as easy drop. In particular, in low-temperature spraying work, there are disadvantages such as liquid dripping, delamination, and set easily occurring due to reduced reactivity (particularly initial activity). On the other hand, when increasing the catalyst on the polyol side to increase the reactivity,
Cold shrinkage becomes severe. Alternatively, when a polyisocyanate containing a large amount of highly active diphenylmethane diisocyanate on the isocyanate side is used, it is known that storage stability is deteriorated due to coagulation at a low temperature.

[0005] HCFC-1 rigid polyurethane foam
In the 41b reduction formulation and the water foaming formulation, various improvement methods on the polyol side have been proposed. For example, in order to improve the adhesion and dimensional stability of the rigid polyurethane foam to the adherend, a polyol component mixture obtained by adding ethylene oxide / propylene oxide to tolylenediamine, triethanolamine, glycerin, ethylenediamine as an initiator is used. The method used (JP-A-6-316)
No. 621), a method of adding an imidazole to a polyol and using a polyisocyanate having a high isomer content to improve adhesion (Japanese Patent Application Laid-Open No. 6-172485). There is known a method of improving adhesion by using a polyisocyanate having an isomer content (Japanese Patent Laid-Open No. 10-204149). Further, a method for improving the dimensional stability of a rigid polyurethane foam using a low functional group / low hydroxyl value polyol and a partially urethane-modified polyisocyanate (Japanese Patent Laid-Open No. 10-265540), or a method of modifying a rigid polyurethane foam with an active hydrogen-containing unsaturated compound A method for improving the dimensional stability and strength of a rigid polyurethane foam by using a polyisocyanate (JP-A-7-102038) and the like are known.

Also, a method for improving the isocyanate side has been proposed. For example, a method using a monol prepolymer of polymethylene polyphenylene polyisocyanate (JP-A-6-172476), a method in which polymethylene polyphenylene polyisocyanate is added to a monofunctional alcohol Using a isocyanate group-terminated prepolymer reacted with a silicone surfactant (JP-A-11-5825)
Is known.

[0007] However, with the recent diversification of uses of rigid polyurethane foams and their higher performance, demands have arisen for rigid polyurethane foams having higher performance. In particular, a polyisocyanate which can sufficiently satisfy market needs for improving workability and quality as a structure, and a HCFC-141b reduction formulation and a water blowing formulation using the same have not been known.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to use a polyisocyanate and a low-viscosity polyol having a good working environment and good storage stability to provide excellent storage stability, workability and foam strength. A rigid polyurethane foam having dimensional stability, adhesiveness, etc. is obtained.
An object of the present invention is to provide a method for producing a rigid polyurethane foam which is a C-141b reduction formulation or a water foaming formulation.

[0009]

Means for Solving the Problems In order to solve the above problems, the present inventors have conducted intensive studies and found that a method for producing a rigid polyurethane foam using a specific rigid polyisocyanate and a specific polyol has been described. The inventors have found that the problems have been solved, and have completed the present invention.

That is, the present invention provides the following (1) and (2)
It is shown in. (1) Polyol (A) and polyisocyanate (B)
Is reacted in the presence of a foaming agent (C), a catalyst (D) and a foam stabilizer (E), wherein the polyol (A) is obtained by adding an alkylene oxide to the (a1) amine compound. A polyether polyol having a hydroxyl value of 250 to 750 mgKOH / g obtained by adding (a2) a hydroxyl value of 150 to 350 mgKOH
/ G polyester polyol (a3) having 3 to 3 functional groups
A polyether polyol having a hydroxyl value of 250 to 750 mgKOH / g, obtained by adding an alkylene oxide to the polyhydric alcohol of No. 6, wherein the polyisocyanate (B) contains diphenylmethane diisocyanate. Polybylene polymethylene polyisocyanate (b1) and an active hydrogen-containing polyether compound (b2) containing at least 70% by mass of oxyethylene groups by (b1) :( b2) =
80:20 to 99.9: 0.1 (mass ratio), containing an isocyanate group-terminated prepolymer obtained by the reaction, and (b1) is diphenylmethane diisocyanate in gel permeation chromatography. Wherein the peak area ratio is 20 to 70%, and the blowing agent (C) is selected from water, hydrocarbon and hydrofluorocarbon.

(2) The active hydrogen-containing polyether compound (b2) is an alkoxypolyethylene glycol and / or
Or the compound having a monoalkoxy polyoxyethylene diol structure.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Each raw material used in the present invention will be described. The viscosity of the polyol (A) used in the present invention is preferably 1,000 mPa · s or less,
800 mPa · s is particularly preferred. When the viscosity exceeds the upper limit, workability particularly in winter is reduced.

(A) is (a1) an amine polyol obtained by adding an alkylene oxide to an amine compound, (a2) a polyester polyol, and (a3) a polyether obtained by adding an alkylene oxide to a polyhydric alcohol. And at least two types selected from polyols.

(A1) is an amine compound such as alkanolamines such as monoethanolamine, diethanolamine and triethanolamine, and polyamines such as tolylenediamine, ethylenediamine, diethylenetriamine, ammonia, aniline, xylylenediamine and diaminodiphenylmethane. Is a polyether polyol having a hydroxyl value of from 250 to 750 mgKOH / g obtained by subjecting an alkylene oxide such as ethylene oxide or propylene oxide to an addition reaction using one or a mixture of two or more of the above as an initiator. Further, the initiator further includes (a) described below.
The polyhydric alcohol used in 2) can be used in combination.

(A2) is ethylene glycol, propanediol, butanediol, diethylene glycol,
Dipropylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol,
Decamethylene glycol, neopentyl glycol, 3
A mixture of one or more polyhydric alcohols such as -methyl-1,5-pentanediol, glycerin, trimethylolpropane, pentaerythritol and adipic acid, malonic acid, fumaric acid, succinic acid, tartaric acid, oxalate Acid, phthalic anhydride, isophthalic acid, terephthalic acid, 1,
It is produced by a known method using one or a mixture of two or more compounds having at least two carboxyl groups (or a group derived from a carboxyl group), such as 4-cyclohexanedicarboxylic acid. And a hydroxyl value of 150 to 350 mgKOH / g. Further, polyester polyols obtained by ring-opening polymerization of lactones (for example, ε-caprolactone) can be mentioned. Further, there may be mentioned a recovered polyester obtained by decomposing a polyester polyol and a polyester molded product.

(A3) is a method in which a polyhydric alcohol having 3 to 6, preferably 3 to 5 hydroxyl groups in one molecule such as glycerin, trimethylolpropane or pentaerythritol is used as an initiator, ethylene oxide,
Hydroxyl value obtained by subjecting an alkylene oxide such as propylene oxide to an addition reaction, 250 to 750 mg KOH
/ G of polyether polyol. The initiator is one or a mixture of two or more of the above-mentioned polyhydric alcohols.

When the hydroxyl value of (a1) to (a3) is less than the lower limit, the mechanical strength of the obtained rigid polyurethane foam becomes insufficient, and when it exceeds this upper limit, the obtained rigid polyurethane foam tends to become brittle.

The average number of functional groups (a1) is preferably from 2 to 8, particularly preferably from 3 to 6. The average number of functional groups in (a2) is preferably 2 to 4, and particularly preferably 2 to 3. The average number of functional groups in (a3) is 3 to 6, preferably 3 to 5. When the average number of functional groups is less than this range, the resulting rigid polyurethane foam has insufficient mechanical strength, and when it exceeds this range, the obtained rigid polyurethane foam tends to be brittle.

The polyol (A) in the present invention comprises (a)
At least two types are selected from 1) to (a3). In the case of only (a1) or only (a3), the mechanical strength of the obtained rigid polyurethane foam tends to be insufficient. In the case of only (a2), the viscosity of (A) becomes too high, and the workability tends to decrease.

The contents of (a1) to (a3) in (A) are (a1): 70% by mass or less, and (a2):
30 mass% or less, (a3): 30 mass% or less is preferable. If the content of (a1) is too large, the activity becomes too high, and it becomes difficult to control the reaction in summer. If the content of (a2) is too large, the viscosity of (A) increases, and the workability in winter tends to decrease. If (a3) is too large, the resulting rigid polyurethane foam tends to have low mechanical strength.

In the present invention, if necessary, (a1) to (a)
Polyols other than 3) can be used. In particular, ethylene glycol (a4), diethylene glycol (a
5) It is preferable to use at least one kind of polypropylene glycol (a6) having a hydroxyl value of 50 to 150 mgKOH / g because the viscosity of (A) can be reduced. In this case, the content of (a4) and / or (a5) in (A) is preferably 20% by mass or less, and the content of (a6) is preferably 10% or less.

Further, a polymer polyol (a7) may be used. The polymer polyol is based on the aforementioned polyether polyol or polyester polyol,
It is a polymer obtained by introducing a vinyl polymer of styrene or acrylonitrile or a polymer obtained from an active hydrogen group-containing compound and a polyisocyanate as a graft polymerization or a filler.

The polyisocyanate (B) used in the present invention is a polyphenylenepolymethylene polyisocyanate (hereinafter abbreviated as polymeric MDI) containing diphenylmethane diisocyanate (hereinafter abbreviated as MDI) which is a so-called binuclear substance. (B1) and an isocyanate group-terminated prepolymer obtained by reacting an active hydrogen-containing polyether compound (b2) containing 70% by mass or more of oxyethylene groups.

(B1) is an MD in gel permeation chromatography (hereinafter abbreviated as GPC).
The peak area ratio of I is 20 to 70%, preferably 25 to 65%. If the peak area ratio of the MDI exceeds 70%, the strength of the obtained rigid polyurethane foam decreases and the rigid polyurethane foam tends to become brittle. If it is less than 20%, the viscosity of the obtained polyisocyanate is high, and spraying tends to be difficult, for example, in spraying work.

The MDI contained in (b1) has two benzene rings and two isocyanate groups in one molecule, and is a so-called binuclear body. MDI
Are 2,2'-diphenylmethane diisocyanate (hereinafter abbreviated as 2,2'-MDI),
2,4'-diphenylmethane diisocyanate (hereinafter, referred to as
2,4'-MDI) and 4,4'-diphenylmethane diisocyanate (hereinafter, abbreviated as 4,4'-MDI). The isomer composition ratio of MDI is not particularly limited, but the 4,4'-MDI content is preferably 70% by mass or more, more preferably 90 to 99.9% by mass, because the strength of the obtained foam is improved. .

From the viewpoint of storage stability and reactivity of (B), the acidity of (b1) is preferably 0.001 to 0.2% by mass, more preferably 0.003 to 0.15% by mass. is there. When the acidity is less than 0.001%, the viscosity of (B) tends to increase during storage, and when it exceeds 0.2%, the reaction with the polyol is slowed, and poor curing is likely to occur.

The "acidity" is a value obtained by converting an acid component which is released by reacting with an alcohol at room temperature into hydrogen chloride, and is a value measured according to JIS K1603 (1985).

In the present invention, if necessary, the aforementioned (b)
Polyisocyanates other than 1) can be used, and examples thereof include modified isocyanurate, modified uretonimine and modified allophanate of MDI. In addition, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylene-1,4-diisocyanate, xylene-1,3-diisocyanate, tetramethylxylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate and the like. Aromatic diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 3-methyl-
Aliphatic diisocyanates such as aliphatic diisocyanates such as 1,5-pentane diisocyanate and lysine diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, and hydrogenated diphenylmethane diisocyanate. In addition, urethane compounds, urea compounds, allophanate compounds, biuret compounds, carbodiimidates, ureton imines, uretdiones obtained by reacting these polymer forms or these isocyanates with an active hydrogen group-containing compound other than (b2) described below. And isocyanurate, and a mixture of two or more of these.

The active hydrogen-containing polyether (b2) used in the present invention contains 70% by mass or more of oxyethylene groups.
Preferably, the content is 80% by mass or more. In addition,
In this case, the “content of oxyethylene groups” indicates the ratio of oxyethylene groups excluding the initiator in the polyether basic unit having oxyethylene / oxypropylene in the structure. If the oxyethylene group content is less than 70% by mass, the dispersibility of (B) in water will be poor, and the reaction will not proceed uniformly.

The average number of functional groups in (b2) is preferably from 1 to 5, and considering the viscosity and dispersibility in water of (B), ethylene oxide is added with an alcohol having from 1 to 2 functional groups as an initiator. Hydroxyl-containing polyethers obtained by the above method are preferred.

The hydroxyl value of (b2) is 50 to 300 mgK
OH / g is preferred, especially 70 to 280 mg KOH / g
Is preferred. When the hydroxyl value is less than the lower limit, the viscosity of the obtained polyisocyanate tends to increase. If the upper limit is exceeded, the reactivity between the obtained polyisocyanate and water tends to decrease.

Specific examples of (b2) include low-molecular-weight monols such as methanol and ethanol, low-molecular-weight polyols such as ethylene glycol, propylene glycol, trimethylolpropane, pentaerythritol, sorbitol, and soucrose, and ethylamine. , Low molecular weight monoamines such as butylamine, ethylenediamine, low molecular weight polyamines such as tolylenediamine, monoethanolamine, diethanolamine, low molecular weight aminoalcohols such as triethanolamine as initiators, ethylene oxide alone or ethylene oxide Obtained by addition polymerization of an alkylene oxide having 70% by mass or more of

In obtaining the isocyanate group-terminated prepolymer, the mass ratio of the charged (b1) and (b2) is (b)
1) :( b2) = 80: 20 to 99.9: 0.1, preferably 85:15 to 95: 5. When the content of (b1) is too small, the mechanical strength of the obtained rigid polyurethane foam tends to decrease. If (b1) is too small,
Reactivity tends to decrease.

As a method for producing the polyisocyanate used in the present invention, a known method can be used. For example, a method in which all of (b1) and all of (b2) are reacted at once, a method in which a part of (b1) is reacted with all of (b2), and then the remaining (b1) is blended, and the like. Can be
The reaction temperature in the reaction (urethane formation reaction) between (b1) and (b2) is 20 to 120 ° C, preferably 40 to 100 ° C.
It is. In addition, at the time of the urethanization reaction, a known urethanization catalyst such as an organic metal compound such as dibutyltin dilaurate or dioctyltin dilaurate, or an organic amine such as triethylenediamine or triethylamine or a salt thereof can be used, if necessary.

The isocyanate content of (B) thus obtained is 24 to 33% by mass, preferably 25 to 3% by mass.
2.8% by mass.

When a polyether compound having an alkoxy polyethylene glycol and / or monoalkoxy polyoxyethylene diol structure is used in (b2),
This is preferable because the reactivity and the physical properties of the foam are improved. “Alkoxy polyethylene glycol” is represented by the formula (1), and “monoalkoxy polyoxyethylene diol structure” is a molecular structure represented by the formula 2.

[0037]

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[0038]

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R in the formulas (1) and (2) is preferably an alkyl group having 1 to 5 carbon atoms. R ′ in the formula (2) may contain atoms other than carbon and hydrogen,
~ 5 are preferred.

Specific examples of the compound having a monoalkoxypolyoxyethylenediol structure include polyether diols represented by the following formulas (3) and (4).

[0041]

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[0042]

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Compounds represented by the formula (3) include PEN-C100 (n = about 2) manufactured by Toho Chemical Industry.
0, Mn = 1,000), PEN-C200 (n = about 4)
3, Mn = 2,000). Examples of the compound represented by the formula (4) include PEN-N50 (n = about 5, Mn = 50) manufactured by Toho Chemical Industry.
0), PEN-N100 (n = about 190, Mn = 1,0
00), PEN-N200 (n = about 42, Mn = 2,0
00).

The polyisocyanate of the present invention may contain a foam stabilizer for improving the compatibility with the polyol, a catalyst for improving the reactivity with the polyol, and the like. If necessary, various known additives and auxiliaries such as antioxidants, ultraviolet absorbers, flame retardants, plasticizers, pigments and dyes, antibacterial agents and antifungal agents can be added.

The blowing agent (C) used in the present invention comprises water,
It is selected from hydrocarbons and hydrofluorocarbons, and water alone is particularly preferred. In addition, you may use together well-known foaming agents normally used for urethane foaming as needed. In the case of water, the amount of the foaming agent (C) added is 5% by mass or less based on the polyol (A), and the amount of the foaming agent other than water, that is, hydrocarbons such as pentane and hexane, HFC-245fa, HFC -365mfc, H
In the case of a hydrofluorocarbon such as FC-134a, the content is 0 to 15% by mass based on the polyol (A).

The catalyst (D) used in the present invention includes:
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-
Examples include tin compounds such as methylmorpholine, dimethylcyclohexylamine, dibutyltin diacetate and dibutyltin dilaurate, and metal complex compounds such as metal salts of acetylacetone. Examples of the trimerization catalyst include triazines such as 2,4,6-tris (dimethylaminomethyl) phenol and 1,3,5-tris (dimethylaminopropyl) hexahydro-s-triazine, and 2,4-bis (dimethylamino). Methyl) phenol, potassium 2-ethylhexanoate, sodium 2-ethylhexanoate, potassium acetate,
Sodium acetate, amine compounds such as aziridines such as 2-ethylaziridine, quaternary ammonium compounds such as tertiary amine carboxylate, lead compounds such as diazabicycloundecene, lead naphthenate, and lead octylate; Examples thereof include alcoholate compounds such as sodium methoxide, and phenolate compounds such as potassium phenoxide. These catalysts can be used alone or in combination of two or more. The amount of (D) used is
An appropriate amount is 0.01 to 15% by mass.

Further, as a co-catalyst for accelerating the reaction, for example, a carbonate compound such as ethylene carbonate and propylene carbonate can be used.

Examples of the foam stabilizer (E) used in the present invention include known silicone surfactants, such as L-5340, L-5420 and L-5 manufactured by Nippon Unicar.
421, L-5740, L-580, SZ-1142,
SZ-1642, SZ-1605, SZ-1649, SH-190, SH made by Dow Corning Toray Silicone
-192, SH-193, SF-2945F, SF-2
940F, SF-2936F, SF-2938F, SR
X-294A, Shin-Etsu Silicone F-305, F-3
41, F-343, F-374, F-345, F-34
8, B-8404, B-840 made by Goldschmidt
7, B-8465, B-8444, B-8467, B-
8433, B-8466, B-8870, B-8450
And the like. An appropriate amount of (E) is 0.1 to 5% by mass based on the polyol.

In the present invention, a flame retardant can be used. Examples of the flame retardant include phosphoric acid compounds such as phosphate esters and phosphite esters.

The rigid polyurethane foam obtained according to the present invention is produced by reacting the thus obtained polyisocyanate containing an isocyanate group-terminated prepolymer with a polyol. In addition,
Prior to foaming, a polyol, a catalyst, a foaming agent, and a foam stabilizer are preferably blended in advance as a polyol premix.

The rigid polyurethane foam of the present invention has a chemical bond such as a urethane bond or a urea bond. Further, depending on the production conditions, an isocyanurate group can be generated during foaming. The isocyanurate group is generated by trimerizing the isocyanate group with a catalyst, and can improve mechanical strength, heat resistance, and the like.

The specific procedure of the method for producing the rigid polyurethane foam of the present invention will be described below.

Using the above-mentioned polyisocyanate (A) containing isocyanate group-terminated prepolymer as liquid A and the above-mentioned polyol (B) as liquid B, foaming agent (C), catalyst (D), foaming agent (E), And the other auxiliaries are obtained by appropriately mixing in advance with the liquid A and / or liquid B, mixing the two liquids using an apparatus described later, and foaming and curing. It is preferable that the foaming agent (C), the catalyst (D), the foam stabilizer (E), and other auxiliaries are mixed in the B liquid.

In the present invention, a preferable isocyanate index is 5 in the case of a so-called urethane foam.
It is from 0 to 140, more preferably from 70 to 130, and in the case of a so-called isocyanurate foam using a trimerization catalyst, it is from 140 to 800, preferably from 150 to 500. Isocyanate index is less than 50 for urethane foam, 1 for isocyanurate foam
When it is less than 40, the obtained foam may not have sufficient strength and may be easily contracted. On the other hand, if it exceeds 140 in the case of urethane foam, and if it exceeds 800 in the case of isocyanurate foam, the resulting foam tends to be brittle and the adhesiveness tends to decrease, which is not preferable.

In producing the rigid polyurethane foam, any apparatus can be used as long as the liquid A and the liquid B can be uniformly mixed. For example, a low-pressure or high-pressure foaming machine for injection foaming, a low-pressure or high-pressure foaming machine for slab foaming, a low-pressure or high-pressure foaming machine for continuous line, and a spraying work used when manufacturing a small mixer or a general urethane foam. Spray foaming machine or the like can be used. Since the isocyanate group-terminated prepolymer of the present invention is a liquid having a relatively low viscosity and a high boiling point and is easy to handle and excellent in workability, it is particularly suitable for spraying work.

In the production of the rigid polyurethane foam, it is preferable that the respective liquid temperatures are adjusted to 30 to 60 ° C.

As described above, the polyisocyanate in the present invention is a uniform and stable liquid, and is particularly excellent in low-temperature storage stability. Further, the polyisocyanate has a low viscosity and a structurally improved compatibility with polyol and water. Also, polyols have low viscosity and high activity. For this reason, when a rigid polyurethane foam is produced as a completely water-foamed formulation, the initial foaming speed is increased, the workability in a low-temperature atmosphere is good, and the foam shrinkage and dimensional stability are good. Further, the adhesiveness to the adherend is also excellent.

The present invention relates to a board, a panel, a refrigerator, an eave,
Doors, shutters, sashes, concrete houses, bathtubs,
It can be applied to various heat insulating materials such as cryogenic tank equipment, freezing warehouse, pipe cover, spraying to plywood, prevention of dew condensation, slab, etc.

[0059]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. In Examples and Comparative Examples, “%” means “% by mass”.
Is shown.

[Preparation of Polyol Premix for Rigid Polyurethane Foam] Formulation Examples 1 to 7 and Comparative Comparative Examples 1 and 2 Polyol premixes OH-1 to OH-9 for rigid polyurethane foam were prepared at the raw materials and charging ratios shown in Table 1. did. The unit of the hydroxyl value is mgKOH / g.

[0061]

[Table 1]

In Table 1, Formulation Examples 1 to 7, Formulation Comparative Example 1,
In 2, polyol (1): hydroxyl value = 450, EO / PO = 40/60 (mass ratio) Initiator = ethylenediamine Polyol (2): hydroxyl value = 300, EO / PO = 20/80 (mass ratio) Initiator = Sucrose / polyamine polyol (3): hydroxyl value = 230, polyester polyol using phthalic anhydride / diethylene glycol as a raw material polyol (4): hydroxyl value = 375, EO / PO = 0/100 (mass ratio) Initiator = Sucrose / glycerin polyol (5): hydroxyl value = 400, EO / PO = 10/90 (mass ratio) Initiator = glycerin polyol (6): hydroxyl value = 430, EO / PO = 100/0 (mass ratio) Initiator = trimethylolpropane polyol (7): hydroxyl value = 1808, ethylene glycol polyol 8): Hydroxyl value = 112, polypropylene glycol Flame retardant (1): Tris (β-chloropropyl) phosphate Foam stabilizer (1): SF-2936F (manufactured by Nippon Unicar) Catalyst (1): Toyocat-L33, amine-based Catalyst (manufactured by Tosoh) Catalyst (2): Toyocat-ET, amine-based catalyst (manufactured by Tosoh) Catalyst (3): Naphtex lead Catalyst (4): Toyocat-RX5, amine-based catalyst (manufactured by Tosoh) EO: oxyethylene Group, PO: represents an oxypropylene group.

[Synthesis of Polyisocyanate for Rigid Polyurethane Foam] Synthesis Example 1 13 kg of MDI (1) and 61 kg of P-MDI (2) were placed in a reactor equipped with a stirrer, cooling pipe, nitrogen inlet pipe, and thermometer.
kg and 24 kg of P-MDI (3) were charged and heated to 40 ° C. while stirring. Then, the polyether (1) was added to 2
kg, and reacted at 80 ° C. for 4 hours with stirring.
Polyisocyanate NCO for rigid polyurethane foam
-1 was obtained. The NCO content of NCO-1 was 30.6%.

Synthetic Examples 2 to 30 and Comparative Comparative Examples 1 to 10 In the same manner as in Synthetic Example 1, polyisocyanates NCO-2 to 40 for rigid polyurethane foam were obtained with the raw materials and charging ratios shown in Tables 2 to 6. . The additives were added after the completion of the reaction.

The resulting polyisocyanates NCO-1 to 40 for rigid polyurethane foam were tested for low-temperature storage stability and water dispersibility. The results are shown in Tables 2 to 6.・ Low-temperature storage stability After synthesis, the state after one month at -5 ° C. was confirmed. ・ Dispersibility Polyisocyanate / water = 500/100 (mass ratio) was dispersed in a lab mixer at 3000 rpm for 30 seconds. Check the status after that

[0066]

[Table 2]

[0067]

[Table 3]

[0068]

[Table 4]

[0069]

[Table 5]

[0070]

[Table 6]

Synthesis Examples 1 to 30, Comparative Examples 1 to 1
0, in Tables 2 to 6, MDI (1): 4,4'-MDI content in MDI = 99% Acidity = 0.006% MDI (2): 4,4'-MDI content in MDI = 50 % Acidity = 0.006% P-MDI (1): Polymeric MDI MDI peak area ratio = 40% 4,4′-MDI content in MDI = 99% Isocyanate content = 31.0% Acidity = 0.015% P-MDI (2): polymeric MDI MDI peak area ratio = 41% 4,4'-MDI content in MDI = 99% isocyanate content = 31.2% acidity = 0.006% P-MDI (3): Polymeric MDI MDI peak area ratio = 34% 4,4'-MDI content in MDI = 99% Isocyanate content = 30.7% Acidity = 0.030% P-MDI (4): Polymeric MDI M I peak area ratio = 20 (%) 4,4′-MDI content in MDI = 99% Isocyanate content = 28.5% Acidity = 0.006% P-MDI (5): polymeric MDI MDI peak area ratio = 15 (%) 4,4′-MDI content in MDI = 99% Isocyanate content = 28.0% Acidity = 0.008% Polyether (1): number average molecular weight = 700 EO / PO = 100/0 ( (Mass ratio) Initiator = methanol Average number of functional groups = 1.0 (MPG081 manufactured by Nippon Emulsifier) Polyether (2): number average molecular weight = 400 EO / PO = 100/0 (mass ratio) Initiator = methanol average number of functional groups = 1.0 (MPG140 manufactured by Nippon Emulsifier) Polyether (3): number average molecular weight = 1,000 EO / PO = 90/10 (mass ratio) Initiator = methanol Average number of functional groups 1.0 (MPG056 manufactured by Nippon Emulsifier) Polyether (4): number average molecular weight = 600 EO / PO = 100/0 (mass ratio) Initiator = ethylene glycol average functional group = 2.0 (PEG600 manufactured by Sanyo Chemical Industries) Polyether (5): number average molecular weight = 1,000 EO / PO = 100/0 (mass ratio) Initiator = ethylene glycol Average functional group number = 2.0 (PEG1000 manufactured by Sanyo Chemical Industries) Polyether (6): Formula Polyether represented by the chemical formula of (1) Number average molecular weight = 1,000 (PEN-C100 manufactured by Toho Chemical Industry) Polyether (7): Polyether represented by the chemical formula of Formula (1) Number average molecular weight = 2,000 (PEN-C200 manufactured by Toho Chemical Industry Co., Ltd.) Polyether (8): Polyether represented by the chemical formula (2) Number average molecular weight = 500 (Toho (PEN-N50 manufactured by Chemical Industry) Polyether (9): polyether represented by the chemical formula of formula (2) Number average molecular weight = 1,000 (PEN-N100 manufactured by Toho Chemical Industry) Polyether (10): formula (2) Polyether represented by the following chemical formula: Number average molecular weight = 2,000 (PEN-N200 manufactured by Toho Chemical Industry) Foam stabilizer (1): silicone-based foam stabilizer (SZ-1642)
Nippon Unicar) Foam stabilizer (2): Silicone foam stabilizer (SF-2936F)
Toray Dow Corning Silicone) Foam stabilizer (3): Silicone foam stabilizer (L-5340 manufactured by Nippon Unicar) Catalyst (1): Dibutyltin dilaurate Catalyst (2): Toyacat L-33 (Amine catalyst Tosoh The catalyst (3): lead octylate The MDI peak area ratio of polymeric MDI was calculated from GPC. EO: oxyethylene group, PO: oxypropylene group.・ Low temperature storage stability ◎ (good) ~ ○ ~ × (poor) ・ Dispersibility ◎ (good) ~ ○ ~ × (poor)

[Production of Rigid Polyurethane Foam] Examples 1-42, Comparative Examples 1-18 A polyisocyanate liquid (liquid temperature: 42 ± 2 ° C.) and a polyol liquid (liquid temperature: 42 ± 2 ° C.) were sprayed and foamed. A rigid polyurethane foam was produced. Tables 7 to 12 show the foam molding results in the urethane formulation. Table 1 shows the results of foam molding in the isocyanurate formulation.
3 and 14. The spray foaming conditions are as follows. Isocyanate index: 110 (urethane), 200 (nurate) Adherend: slate plate, veneer plate Foaming machine: gasmer spraying foaming machine FF-1600 type (urethane) H-2000 type (nurate) Primary heater temperature: 42 ° C. Hose heater Temperature: 40 ° C. Adherend temperature: 15 ° C. Foam thickness: 30-40 mm

[0073]

[Table 7]

[0074]

[Table 8]

[0075]

[Table 9]

[0076]

[Table 10]

[0077]

[Table 11]

[0078]

[Table 12]

[0079]

[Table 13]

[0080]

[Table 14]

In Tables 7 to 14, free foaming density: density of foam core Cell condition: visually evaluated 1 (fine) to 5 (coarse) Shrink at normal temperature: Shrinkage of foam after foaming and left for 1 day at normal temperature ○ (small shrinkage)-△-× (large shrinkage) Closed cell rate: Polymer Engineering Course 14 Polymer Materials Testing Method, edited by The Society of Polymer Science, 430 pages, Jinjinshokan, "(E) Independent Measurement of air bubble ratio ”Dimensional stability: Measure the dimensions before and after the aging condition and evaluate based on the rate of change. Aging condition Urethane formulation 70 ° C / 1 day, -20 ° C / 1 day Isocyanurate formulation 100 ° C / 1 day -20 ° C / 1 day Compressive strength: Measured according to JIS A-9526 Adhesive strength: Measured according to JIS A-9526

As shown in Tables 7 to 14, the rigid polyurethane foam using the polyisocyanate in the present invention was excellent in dimensional stability. However, rigid polyurethane foams using an unmodified polyisocyanate or an isocyanate group-terminated prepolymer containing too much modifier had poor dimensional stability.

Continued on the front page F term (reference) 4J034 DF01 DF14 DG02 DG14 DG22 HA01 HA07 HC12 HC64 HC67 HC71 JA42 KA01 NA01 NA02 NA03 NA05 QA02 QB16 QC01 RA03 RA10

Claims (2)

[Claims] 1. A process for producing a rigid polyurethane foam, comprising reacting a polyol (A) with a polyisocyanate (B) in the presence of a foaming agent (C), a catalyst (D) and a foam stabilizer (E). (A) has a hydroxyl value of 250 obtained by adding an alkylene oxide to the (a1) amine compound.
(A2) Polyester polyol having a hydroxyl value of 150 to 350 mg KOH / g, (a3) hydroxyl value obtained by adding an alkylene oxide to a polyhydric alcohol having 3 to 6 functional groups, and a hydroxyl value of 250 to 250 mg KOH / g. 750 mgKOH / g of a polyether polyol, wherein at least two kinds are selected from the group consisting of polyisocyanate (B), polyphenylene polymethylene polyisocyanate (b1) containing diphenylmethane diisocyanate, and oxyethylene group of 70%.
(B1) :( b2) = 80: 20-99.
It contains an isocyanate group-terminated prepolymer obtained by reacting at a ratio of 9: 0.1 (mass ratio), and (b1) has a peak area ratio of diphenylmethane diisocyanate of 20 in gel permeation chromatography. To 70%, and the blowing agent (C) is selected from water, hydrocarbons and hydrofluorocarbons. 2. An active hydrogen-containing polyether compound (b)
The method according to claim 1, wherein 2) is a compound having an alkoxypolyethylene glycol and / or a monoalkoxypolyoxyethylenediol structure.