JP3389588B2 - Method for producing rigid polyurethane foam using polyisocyanate mixture for rigid foam - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to a heat insulating material, a lightweight structural material,
A hard foil with an isocyanurate ring, suitable for sound absorbing materials, etc.
The present invention relates to a method for producing a rigid polyurethane foam obtained by using a foaming polyisocyanate mixture.

[0002]

2. Description of the Related Art Organic polyisocyanates are used in various applications such as foams, elastomers, paints and adhesives by reacting with various active hydrogen group-containing compounds. Organic polyisocyanates for obtaining foam are heat resistant,
In order to improve the flame retardancy, etc., the organic polyisocyanate is modified and used, but the obtained foam has a heat insulating property,
Further improvements have been demanded in terms of lightness, sound absorption and the like.

For example, JP-A-54-32490,
Japanese Patent Laid-Open No. 52-69497 describes a method for producing an isocyanurate ring using a catalyst such as a metal salt of acetylacetone or an alkali metal salt of an organic acid. However, when it is used as an aromatic polyisocyanate, particularly in the case of diphenylmethane diisocyanate (hereinafter abbreviated as MDI), the product has a high viscosity, a low NCO group content, and a low compatibility with other resins. There is. In addition, JP-A-2-3002
No. 24, JP-A-3-20322, JP-A-3-26714 and the like use various specific additives such as an organic phosphite ester, a surfactant and a ferrocene compound together with a trimerization catalyst. It has a particularly flame-retardant effect when the foam is obtained.

[0004]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention As a result of extensive studies and researches on a method for producing an organic polyisocyanate and a rigid polyurethane foam, the present inventors have converted the organic polyisocyanate into an isocyanurate to form tolylene diisocyanate (hereinafter referred to as TDI). The inventors have found that the improvement can be achieved by using a specific isocyanate in which a compound and an MDI-based polyisocyanate are mixed, if necessary, and have reached the present invention.

[0005]

That is, the present invention is to add a trimerization catalyst, a cocatalyst, and a surfactant to a carbodiimide modified product of polymethylene polyphenyl polyisocyanate and polyisocyanate to obtain 20% by weight of all isocyanate groups.
The following are converted to isocyanurate, and an isocyanurate ring-containing NCO content of 28.5 to 30.0% by weight, which is obtained by adding a terminating agent if necessary, and a modified tolylene diisocyanate compound and an organic polyisocyanate are used. NC formed by mixing 2 to 60 parts by weight of tolylene diisocyanate compound with 100 parts by weight of modified product
A trimerization catalyst, a cocatalyst and a surfactant were added to a polyisocyanate mixture for rigid foams having an O content of 28.0 to 32.0% by weight, or a carbodiimide modified product of polymethylene polyphenyl polyisocyanate and polyisocyanate, NCO content having isocyanurate ring obtained by converting 20% by weight or less of an isocyanate group into isocyanurate and adding a terminating agent if necessary 28.5 to 3
An organic polyisocyanate modified product of 0.0 wt% and a tolylene diisocyanate compound are mixed in an amount of 2 to 60 parts by weight of the tolylene diisocyanate compound with respect to 100 parts by weight of the modified organic polyisocyanate, and the mixture is further mixed. > NCO content of 28.0 to 32.0% by weight formed by mixing diphenylmethane diisocyanate-based polyisocyanate
To the polyisocyanate mixture for rigid foams, a polyol having a molecular weight of 400 to 6000, a low molecular weight active hydrogen group-containing compound having a molecular weight of 62 to less than 400, a foaming agent and, if necessary, a surfactant and an additive are reacted. It is a characteristic method of producing a rigid polyurethane foam.

The resin liquid for rigid polyurethane foam according to the present invention has very good foamability and is excellent in filling in a mold having a complicated shape. Further, the obtained foam has excellent properties such as excellent heat insulating property, light weight property and sound absorbing property, and no change with time of cells.

The organic polyisocyanates used in the present invention are polymeric MDI and carbodiimidated modified products.
Is. Cal for 100 parts by weight of Polymeric MDI
Bodiimidated modified product 20 to 70 parts by weight, preferably cal
It is 30 to 50 parts by weight of the modified bodiimidized product.

Examples of the TDI compound include 2,4-TDI and 2,6-TDI, alone or in any mixture, and polymeric TDI. Or, these TDI and molecular weight 62
To 6000 and the number of functional groups is 8 or less, preferably 3 to
40% by weight of the total NCO groups with 6 active hydrogen group-containing compounds
The compound which made the following react can be mentioned.

Examples of the active hydrogen group-containing compound used in the reaction of these polyisocyanates include ethylene glycol, propanediol, butanediol, diethylene glycol, dipropylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, Neopentyl glycol, 3-methyl 1,5-pentanediol, glycerin, trimethylolpropane, pentaerythritol, sucrose, glucose, fructose sorbitol, etc., or a mixture of two or more thereof, ethylenediamine, propylenediamine, diethylenetriamine, toluenediamine, meta. Amines such as phenylenediamine, diphenylmethanediamine, xylylenediamine, etc., alone or in combination of two or more Or a monomer such as ethylene oxide, propylene oxide, butylene oxide, amylene oxide, glycidyl ether, methyl glycidyl ether, t-butyl glycidyl ether, phenyl glycidyl ether, etc., using one or more of these compounds as an initiator Or the thing obtained by carrying out addition polymerization of the more than that by a well-known method is mentioned. The reaction between the polyisocyanate and the active hydrogen group-containing compound is preferably 40% by weight or less of the total NCO groups. 40
If it is more than weight%, the effect of the isocyanurate ring structure cannot be obtained. Further, by reacting TDI with an active hydrogen group-containing compound for use, compatibility between various components of the foaming raw material is improved, and foamability and physical properties are improved.

As the MDI-based polyisocyanate used in the present invention, MDI, polymeric MDI, or a mixture thereof alone or in an arbitrary mixture is used.

The trimerization catalyst used in the present invention includes
2,4,6-Tris (dimethylaminomethyl) phenol, N, N ', N "-tris (dimethylaminopropyl) hexahydrotriazine, mixture of potassium octylate and diethylene glycol, tertiary amine, potassium octylate and diethylene glycol , Potassium phenolate, phenolates such as sodium methoxide, alcoholates, and more particularly effective 2,4,6-tris (dimethylaminomethyl) phenol, 2,4-bis (dimylaminomethyl) phenol, 2,6-di-t.
-Butyl-4-dimethylaminotrimethylsilanephenol, triethylamine diazabicycloundecene. The amount of the trimerization catalyst used varies depending on the activity of the catalyst, but is 0.005 to polyisocyanate.
1.0 wt% is sufficient.

Examples of the cocatalyst used in the present invention include phosphite ester and phosphoric acid ester. Examples of the phosphite ester include phosphite diester and phosphite triester. Examples of phosphite diesters include dilauryl hydrogen phosphite,
Diphenyl hydrogen phosphite and the like can be mentioned.
Examples of phosphite triesters include triethyl phosphite, triptyl phosphite, tris (β-chloroethyl) phosphate, tris (β-chloropropyl) phosphate and the like. The amount of the co-catalyst used may be 1/10 to 20 times the weight of the polyisocyanate.

As the surfactant used in the present invention,
For example, a polyglycol ether containing the required number of alkylene oxides such as propylene oxide, butylene oxide, preferably ethylene oxide, and at least 1
It is obtained by condensing with an organic compound containing one reactive hydrogen atom. Such organic compounds containing at least one reactive hydrogen atom include alcohols, phenols, thiols, primary or secondary amines, carboxylic acids or sulfonic acids, and their amides. Examples of the agent include surfactants and the like, which are polyalkylene oxide derivatives of phenolic compounds having one or more alkyl substituents. Further, preferred surfactants in the present invention include pluronic type surfactants, which are generally
1,2-alkylene oxides or substituted alkylene oxides, such as butylene oxide, amylene oxide, phenylethylene oxide, cyclohexene oxide, propylene oxide, or mixtures thereof, are polymerized in the presence of an alkali catalyst and are insoluble in the corresponding water. Is a nonionic surfactant obtained by producing the above polyalkylene glycol and condensing it with the required number of moles of ethylene oxide under the same conditions. Furthermore, it is obtained by reducing an aldehyde produced by a catalytic reaction of a polyolefin such as tripropylene, tetrapropylene, pentapropylene, ditosobutylene, triisobutylene, tetrabutylene, propylene-sobutylene and tributene with carbon monoxide and hydrogen. A nonionic surfactant obtained by reacting the required alcohol with the required number of moles of ethylene oxide can be used. The amount of such a surfactant used is 0.1 to 2% by weight based on the polyisocyanate.

The reaction for obtaining the modified organic polyisocyanate of the present invention can be carried out at a reaction temperature of 100 ° C. or lower, preferably 20 to 70 ° C. Reaction temperature is 100 ℃
When it becomes the above, since a high molecular body of an isocyanurate body or a high molecular body of an allophanate compound is easy to be generated, compatibility may be lowered or gelation may occur. By selecting a suitable amount of isocyanurate-forming catalyst and reaction temperature, the isocyanurate-forming reaction proceeds sequentially, so that it can be easily carried out by a conventional production apparatus. Further, the NCO content and viscosity of the resulting isocyanurate-containing modified polyisocyanate can be freely changed by adjusting the NCO content at the time of stopping the reaction. The isocyanurate-forming reaction according to the present invention has the advantages that a small amount of catalyst is used and that the reaction can be carried out at a low temperature in a short time.

In the reaction for obtaining the modified organic polyisocyanate of the present invention, an acidic compound can be used as a terminating agent. For example, phosphoric acid, dimethyl phosphate, trimethyl phosphate, triethyl phosphate, tricresyl phosphate, triphenyl phosphate, triphtyl phosphate, p
-Toluenesulfonic acid, methyl p-toluenesulfonate, xylenesulfonic acid, benzenesulfonic acid, methanesulfonic acid, alkylbenzenesulfonic acid, dinaphthalenemonosulfonic acid, dinaphthalenedisulfonic acid, dinonylnaphthalenemonosulfonic acid, benzoyl chloride,
Examples include acetyl chloride and the like, and similar compounds thereof. The isocyanurate-forming terminating agent is preferably used in an amount of 0.3 to 5.0 times equivalent to the catalyst amount,
It is more preferable to use ˜2.0 times equivalent amount. By adding the isocyanurate-stopping agent to the reaction system, the reaction product can be stabilized without the reaction solution becoming turbid. Also, the use of phosphoric acid as a terminating agent can improve the flame retardancy of the foam.

The NCO content of the modified organic polyisocyanate thus obtained is 28.5 to 30.0% by weight.
is there. In the case of a TDI compound, the NCO group partially modified has an NCO content of 28.0 to 40.0% by weight, preferably 31,0 to 36,0% by weight.

The polyisocyanate mixture for rigid foams of the present invention comprises a modified organic polyisocyanate thus obtained, a TDI compound and, if necessary, a polymeric M.
It consists of DI. The use ratio of such isocyanates is 200 parts by weight or less of the polymeric MDI with respect to 100 parts by weight of the modified product. In addition, the modified body 1
The amount of the TDI compound is 2 to 60 parts by weight based on 00 parts by weight. The NCO group content of the polyisocyanate mixture is 2
8.0-32.0% by weight, preferably 29.0-31.
It is 0% by weight.

The polyol used in the production of the foam of the present invention has a molecular weight of 400 to 6000 and 2 to 2 molecular weights.
A polyol having 8 hydroxyl groups and / or a molecular weight of 6
It is a compound having a low molecular weight active hydrogen group of 2 to less than 400.
If the molecular weight of these polyols is less than 200, the foam becomes extremely hard and brittle, and a foam having sufficient strength cannot be obtained. Typical examples are polyether polyols and polyester polyols. These polyols can be used alone or in combination of two or more.

As the polyether polyol which can be used in the present invention, for example, ethylene glycol, propanediol, butanediol, diethylene glycol, dipropylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, 3-methyl 1,5-pentanediol, glycerin, trimethylolpropane, pentaerythritol, sorbitol,
Further, sugar-based alcohols such as sucrose, glucose and fructose, bisphenol A, ethylenediamine, propylenediamine, diethylenetriamine,
Using one or more compounds having two or more active hydrogens such as toluenediamine, metaphenylenediamine, diphenylmethanediamine, xylylenediamine, etc. as an initiator, ethylene oxide, propylene oxide,
It is produced by addition-polymerizing one or more monomers such as butylene oxide, amylene oxide, glycidyl ether, methyl glycidyl ether, t-butyl glycidyl ether and phenyl glycidyl ether by a known method.

Examples of polyester polyols include ethylene glycol, propanediol, butanediol, diethylene glycol, dipropylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, 3-methyl 1,5. -Pentanediol, glycerin, trimethylolpropane,
One or more compounds having at least two hydroxyl groups, such as pentaerythritol, sorbitol, and bisphenol A, and adipic acid, malonic acid, succinic acid, tartaric acid, pimelic acid, sebacic acid, oxalic acid, and phthalate. Acid, terephthalic acid, azelaic acid, trimellitic acid, curtaconic acid, α-hydromuconic acid, β-hydromuconic acid, α-butyl-α-ethylglutaric acid,
α, β-diethylsuccinic acid, hemimellitic acid, 1,4
It can be produced by a known method using one or more compounds having at least two carboxyl groups, such as cyclohexanedicarboxylic acid.

A preferred polyol has a molecular weight of 500 to 3
000 polyether polyols. These include, for example, those from sorbitol, sucrose, tolylenediamine, exemplified by Exenol EL-375.
S, EL-450S, EL-455S, EL-3
75A, EL-450SA, EL-452SA, EL-400SO, EL-451SA, EL-45
0ED, EL-500ED, EL-350AR, EL-463AR, EL-450AR, EL-45
5AR, EL-495AR, etc. made by Asahi Glass, Sannix SP-750, HC-450, HS-209, HR-450P, RP-410A, Sanyo Kasei Kogyo, Toho Polyol ON-595, the same. O-850,
Same O-619, same AR-2538, same AR-2577,
Examples include Asahi Denka Co., Ltd., such as AR-2589 and Toho Kagaku, and Adeka Polyether SP-600, SP-690, SC-1000, SC-1001, and SC-800.

The foams of the invention have a molecular weight of 62
A low molecular weight active hydrogen group-containing compound having a molecular weight of less than 400 can be used in combination. These include, for example, glycols such as ethylene glycol, propanediol, butanediol, diethylene glycol, dipropylene glycol, and tripropylene glycol, and polyhydric alcohols such as glycerin and trimethylolpropane, ethylenediamine, propylenediamine, diethylenetriamine, and toluene. Examples thereof include diamines, metaphenylenediamines, diphenylmethanediamines, xylylenediamines, and the like, or a mixture of two or more kinds of compounds having two or more active hydrogens, or an addition polymer of these compounds and alkylene oxide. . These include, for example, Exenol EL-400MP, EL-890MP, E
Made by Asahi Glass such as L-330, Sannix GP-250,
Sanyo Kasei Co., Ltd., such as GP-400, TP-300, TP-400, Adeka polyether G-400, G
-300, T-400 etc. made by Asahi Denka, Niax A
Examples include those manufactured by Union Carbite such as PP-315.

The low molecular weight active hydrogen group-containing compound is used in a proportion of 50 parts by weight or less based on 100 parts by weight of the above-mentioned polyol or a mixture of the above-mentioned polyols. The molecular weight of these mixtures is usually 200 to 4000. A preferred usage ratio of the polyol and the low molecular weight active hydrogen group-containing compound is 40 parts by weight or less based on 100 parts by weight of the polyol.

As the foaming agent used in the production of the foam of the present invention, known chemical foaming agents and / or physical foaming agents can be used in usual amounts, for example, acetone, pentane, hexane and the like. Low boiling point inert solvent, HC
Even if an alternative CFC such as FC-141b or 123 or water is used, the form of the present invention can be obtained. In the production of the foam of the present invention, the above-mentioned surfactant can be used if necessary. Further, known additives such as fillers, plasticizers, colorants, flame retardants and the like can be used in combination.

The rigid polyurethane foam of the present invention is produced by adding a polyisocyanate mixture, a polyol, a low molecular weight active hydrogen group-containing compound, a foaming agent and, if necessary, a surfactant and an additive to prepare an NCO / active hydrogen compound ( The molar ratio is 0.5 to 1.5, preferably 0.8 to 1.2, and the components are stirred at 10 to 40 ° C. and 2000 to 8000 rpm for 3 to 10 seconds, mixed, and immediately poured into a molding die. Alternatively, foaming can be performed using a low-pressure or high-pressure foaming machine which is generally used in urethane foam manufacturing equipment. In this case, the mold or free foam container is
The foaming time can be shortened by heating to 0 ° C. or higher.

The thus obtained rigid polyurethane foam has heat insulating properties, performance as a lightweight structural material, sound absorbing properties, and the like, so that it is used in the field of building materials, household articles, leisure articles, etc., for example, refrigerators, It can be applied to freezer, cooler box, vending machine, showcase, etc.

[0027]

EFFECT OF THE INVENTION Compatibility with polyols and various other components
Good, excellent long-term storage stability, and very good foamability
A book with excellent filling properties for molds with complicated shapes
The foam obtained using the polyisocyanate mixture for rigid foams of the invention has excellent properties such as excellent heat insulation and no change over time in the cell. Particularly when flame retardancy is required, the effect can be obtained by using phosphoric acid as a terminating agent at the time of isocyanurate formation, using a flame retardant, and the like.

[0028]

The present invention will be described below with reference to examples.
The present invention is not limited to these examples. "Parts" and "%" in the examples are "parts by weight" and "% by weight", respectively. The isocyanurate formation was confirmed by infrared absorption spectrum.

Production Examples 1 to 3 Production of Modified Organic Polyisocyanate The organic polyisocyanate shown in Table 1, a trimerization catalyst, a cocatalyst, a surfactant and the like are added to carry out an isocyanurate-forming reaction under the conditions shown in Table 1. The reaction was stopped by adding a terminator and stirring at 50 ° C. for 5 hours. Table 1 shows the obtained modified organic polyisocyanate.

[0030]

[Table 1]

In Table 1, poly MDI (1): (Polymeric MDI, manufactured by Nippon Polyurethane Industry Co., Ltd., Millionate MR-200, NCO content 3
1.0%, 80 parts, carbodiimide modified product, manufactured by Nippon Polyurethane Industry Co., Ltd., Millionate MTL, NCO content 29.
5%, 20 parts mixture) Poly MDI (2): (Millionate MR-200, NCO
Mixture of 31.0% content 70 parts, Millionate MTL, NCO content 29.5%, 30 parts) Ancamine K-54: isocyanurate forming catalyst (component:
2,4,6-Tris (dimethylaminomethyl) phenol) ACII Phylol CEF: Tris (β-chloroethyl) phosphate, Akzo Perlon 9338: Tris (β-chloropropyl) phosphate, Perlon L-5340: Silicone surfactant, made by Union Carbide

Preparation Examples 1 to 3 Preparation of Polyisocyanate Mixture Using the modified organic polyisocyanates obtained in Production Examples 1 to 3 , polyisocyanate mixtures were prepared under the conditions shown in Table 2. Properties of the mixture are shown in Table 2.

[0033]

[Table 2]

In Table 2, TDI: Nippon Polyurethane Industry Co., Coronate T-8
0, isomer 2,4- / 2,6-isomer 80:20 Urea TDI (1): 100 parts of Coronate T-80 and 3.7 parts of ethylenediamine (amine value 3840) at 50 ° C. for 2 hours Obtained by reacting for a time, NCO content 36.
0% Polymeric TDI: NCO content 35.0%.

Examples 1 to 3 Production of Rigid Polyurethane Foam After adjusting the isocyanate component and the polyol component shown in Table 3 respectively to 20 ° C. ± 1 ° C., they were weighed in a 2.0-liter polyethylene beaker and rotated at 5000 rpm. The mixture was stirred and mixed for 2 to 5 seconds with a stirring mixer, and free-foaming was performed while setting a polyethylene bag in a 250 × 250 × 250 mm aluminum container preliminarily kept at 40 ° C.
Foamability was tested. The results are shown in Table 4. In addition, the foam stock solution which was similarly mixed by stirring was kept at 40 ° C and kept at 500 x 5
The foam obtained by pouring into a vertical aluminum mold of 00 × 60 mm was used for the physical property test. The performance of the obtained foam is shown in Table 4. Further, a reverse L-shaped mold (30 x 500 x 5
Flowability from foam obtained by pouring into 00 × 300 mm,
The filling property and the like were examined. The results are shown in Table 4.

[0036]

[Table 3]

In Table 3, polyol A: sucrose type polyol, hydroxyl value = 450, number of functional groups 6.25, molecular weight = 800, polyol B: sorbitol type polyol, hydroxyl value =
550 Polyol C: Tolylenediamine-based polyol, hydroxyl value = 430 Polyol D: Glycerin-based polyol, hydroxyl value = 515, functional group number 3, molecular weight = 330 Polyol E: Ethylenediamine-based polyol, hydroxyl value = 450, functional group number 4, molecular weight = 500 Polyol F: phthalic acid type polyester polyol, hydroxyl value = 315, functional group number 2, molecular weight = 350 DMCHA: abbreviation of dimethylcyclohexylamine, catalyst DMEA: abbreviation of dimethylethanolamine, catalyst L-5340: silicone surfactant, Union Carbide R-141b: Freon foaming agent, Central Glass

[0038]

[Table 4]

In Table 4, flowability: The foam was taken out from the mold, and the volume occupied by the foam was determined for judgment. Fillability: The form was taken out from the mold and judged. ⊚: Excellent ○: Normal Δ: Slightly inferior ×: Inferior dimensional stability: According to JIS K6767. Thermal conductivity: A thermal conductivity measuring device manufactured by Anacon was used.

Continuation of the front page (56) Reference JP-A-2-300224 (JP, A) JP-A-59-108025 (JP, A) JP-A-50-131977 (JP, A) JP-A-8-73557 (JP , A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 18/76-18/79

Claims (2)

(57) [Claims] 1. A trimerization catalyst, a cocatalyst and a surfactant are added to a carbodiimide modified product of polymethylene polyphenyl polyisocyanate and polyisocyanate to convert 20% by weight or less of all isocyanate groups into isocyanurate. An isocyanurate ring-containing organic polyisocyanate-modified product having an NCO content of 28.5 to 30.0% by weight and a tolylene diisocyanate compound are obtained by adding a terminating agent to the organic polyisocyanate-modified product 10.
Tolylene diisocyanate compound 2 to 0 parts by weight
NCO content formed by mixing 60 parts by weight 28.0 to 32.0
To a polyisocyanate mixture for rigid foam of wt%,
Polyol having a molecular weight of 400 to 6000, molecular weight of 62 to 4
A method for producing a rigid polyurethane foam, which comprises reacting a compound containing a low-molecular active hydrogen group having a molecular weight of less than 00, a foaming agent and, if necessary, a surfactant and an additive, to cause a reaction. 2. A trimerization catalyst, a cocatalyst and a surfactant are added to a carbodiimide modified product of polymethylene polyphenyl polyisocyanate and polyisocyanate to convert 20% by weight or less of all isocyanate groups into isocyanurate, which is required. An isocyanurate ring-containing organic polyisocyanate-modified product having an NCO content of 28.5 to 30.0% by weight and a tolylene diisocyanate compound are obtained by adding a terminating agent to the organic polyisocyanate-modified product 10.
Tolylene diisocyanate compound 2 to 0 parts by weight
60 parts by weight, and further mixed with diphenyl <br/> diisocyanate-based polyisocyanate mixture
An NCO content of 28.0 to 32.0 wt% of the rigid foam for the polyisocyanate mixtures comprising Te, molecular weight from 400 to 6
000 polyol, a low molecular weight active hydrogen group-containing compound having a molecular weight of 62 to less than 400, a foaming agent and, if necessary, a surfactant and an additive are added and reacted.