JPH1030033A - Production of rigid foamed synthetic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a rigid polyurethane foam having a low heat conductivity by using a foaming agent low in ozonolysis coefficient. SOLUTION: This method for producing a rigid foamed synthetic resin comprises reacting a polyisocyanate compound with an active hydrogen compound having two or more active hydrogen atom-containing functional groups capable of reacting with isocyanate groups in the presence of a foaming agent, a catalyst and other auxiliaries. Therein, cyclopnentane and water are used as the foaming agent, and the alkylene oxide adduct of a diaminodiphenylmethane compound or polymethylenepolyphenylamine compound is used as a part of the active hydrogen compound.

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 foam synthetic resin which is particularly suitable for obtaining a heat insulating material having a low thermal conductivity by using cyclopentane or the like as a foaming agent.

[0002]

2. Description of the Related Art As a foaming agent, R-141b (1,1-dichloro-1-fluoroethane) or water (CO ₂ gas by-produced in the reaction with isocyanate) is used to prevent the destruction of the ozone layer by specific fluorocarbons. Foaming).

[0003] However, the use of foaming with water is not preferable because of the high thermal conductivity of this CO ₂ gas, and it is particularly difficult to use it as a heat insulating material for electric refrigerators. R-14
With respect to 1b, the ozone depletion potential (ODP) is as large as 0.11 and the time dependence of this ODP is large, so that movements to restrict its use have been taking place in Europe and the United States. In fact, the 7th Montreal Protocol Parties Meeting at the end of last year was totally abolished in 2020, ten years ahead of schedule.

[0004] Cyclopentane has already been used as a blowing agent mainly in Europe. The reason is OD
The point is that P is zero. However, while cyclopentane itself is a compound having high hydrophobicity, polyols for rigid foamed synthetic resins generally have high hydrophilicity in many cases.
Therefore, when cyclopentane is used as a foaming agent for a rigid foam synthetic resin, it is desirable that active hydrogen compounds such as polyols have high mutual solubility. At the same time, since the thermal conductivity of cyclopentane itself is higher than that of R-141b, it is necessary to devise a method of reducing the thermal conductivity.

[0005]

To solve these problems, the inventors of the present invention have studied and found that when cyclopentane is used as a foaming agent, the bubbles in the foam are made uniform and fine. Reduces the effect of radiant heat transfer,
As a result, it was found that the heat insulating property could be improved. It is considered that an appropriate reaction rate is required to make the bubbles in the foam uniform and fine. In order to increase the initial reactivity of the polyol, the hydroxyl group of the polyol has already been converted to a primary hydroxyl group. Further, as a device for improving the reactivity with the isocyanate, the compatibility between the polyol and the isocyanate is increased.

The inventors of the present invention not only improve the mutual solubility of cyclopentane and polyol, but also improve the compatibility between polyol and isocyanate to make the bubbles in the foam uniform and fine, thereby contributing to the improvement of heat insulation. I found that.

[0007]

Means for Solving the Problems The present inventors have selected a specific compound as an active hydrogen compound in order to improve the mutual solubility of cyclopentane or the like and a polyol, thereby making the bubbles in the foam uniform and fine, and insulating the foam. It has been found that it contributes to improvement of the performance.

That is, the present invention relates to a method of reacting an active hydrogen compound having two or more active hydrogen-containing functional groups capable of reacting with an isocyanate group with a polyisocyanate compound in the presence of a blowing agent, a catalyst and other auxiliaries. In a method for producing a foamed synthetic resin, the foaming agent has 2 to 8 carbon atoms.
A method for producing a rigid foam synthetic resin, comprising using a hydrocarbon or water thereof and water, and using an alkylene oxide adduct of diaminodiphenylmethanes or polymethylene polyphenylamines as at least a part of the active hydrogen compound. is there.

[0009]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, as an active hydrogen compound having two or more active hydrogen-containing functional groups capable of reacting with an isocyanate group, an alkylene oxide (hereinafter referred to as AO) of diaminodiphenylmethanes or polymethylene polyphenylamines is used. ) Use adducts. The diaminodiphenylmethanes or polymethylene polyphenylamines preferably have the structure of the formula (1).

[0010]

Embedded image

In the formula (1), R is a hydrogen atom or a group having 1 carbon atom.
To 6 alkyl groups, and a plurality of Rs may be the same or different. n is an integer of 0-4. n is preferably 0, and R is preferably a hydrogen atom or a methyl group. Among those showing the structure of the formula (1), those showing the structure of the formula (2) are particularly preferable.

[0012]

Embedded image

In the formula (2), R is a hydrogen atom or a group having 1 carbon atom.
To 6 alkyl groups, and a plurality of Rs may be the same or different. The most preferred compound is 4,4 '
-Diaminodiphenylmethane.

The AO adduct of diaminodiphenylmethanes or polymethylenepolyphenylamines can be obtained by adding AO to diaminodiphenylmethanes or polymethylenepolyphenylamines in the presence of a catalyst such as an alkali catalyst. The AO adduct has a hydroxyl value of 20 to 100.
0 mgKOH / g, especially 100-800 mgKOH / g
g, more preferably 200 to 600 mgKOH / g.

As AO, AO having 2 to 4 carbon atoms is particularly preferable, and propylene oxide (hereinafter, referred to as PO), ethylene oxide (hereinafter, referred to as EO), and a combination thereof are preferable. When PO and EO are used in combination, they can be reacted randomly or sequentially. In particular, a compound having a primary hydroxyl group at a terminal can be obtained by reacting PO with EO.

In the present invention, an active hydrogen compound other than the above-mentioned AO adduct may be used in combination. The active hydrogen compound that can be used in combination is a compound having two or more active hydrogen-containing groups such as a hydroxyl group, a primary amino group or a secondary amino group, and a polyol widely used is preferably used. A compound having two or more phenolic hydroxyl groups (for example, a phenol resin precondensate) can also be used.

As the polyol, polyether polyol, polyester polyol, polyhydric alcohol,
There is a diene polymer having a hydroxyl group. In particular, it is preferable to use only one or more polyether-based polyols or to use them as a main component in combination with a polyhydric alcohol and other active hydrogen compounds.

The polyether polyol is preferably obtained by reacting the above AO in the presence of a catalyst such as an alkali catalyst and an initiator. Initiators include ethylene glycol, propylene glycol, diethylene glycol,
Polypropylene alcohol such as dipropylene glycol, glycerin, trimethylolpropane, pentaerythritol,
Saccharides such as sucrose, alkanolamines such as monoethanolamine, diethanolamine and triethanolamine, polyamines such as tolylenediamine, polyphenols such as bisphenol A, and those obtained by adding a small amount of AO to these Low molecular weight polyether-based polyols.

Examples of the compound having two or more phenolic hydroxyl groups include a resol type initial condensate obtained by condensing a phenol with an excess formaldehyde in the presence of an alkali catalyst, and a resol type initial condensate. And a novolak-type precondensate obtained by reacting excess phenols with formaldehyde in the presence of an acid catalyst. The molecular weight of these precondensates is preferably about 500 to 10,000.

In the above, phenols mean those in which one or more carbon atoms of a skeleton forming a benzene ring are directly bonded to a hydroxyl group, including those having other substituents in the same structure. Representative examples include phenol, cresol, bisphenol A, resorcinol, and the like. The formaldehyde is not particularly limited, but formalin, paraformaldehyde and the like are preferable.

In the present invention, it is particularly preferable to use a polyether polyol obtained by reacting AO with a compound having an aromatic ring other than diaminodiphenylmethanes or polymethylene polyphenylamines as an initiator. Specifically, a polyether-based polyol having an aromatic polyamine such as tolylenediamine as an initiator,
A polyether-based polyol having a polyhydric phenol such as bisphenol A as an initiator and a combination thereof are preferred.

The polyol has a hydroxyl value of 20 to 100.
0 mgKOH / g, especially 100-800 mgKOH / g
g, more preferably 200 to 600 mgKOH / g.

In the present invention, a hydrocarbon having 2 to 8 carbon atoms or water and the same are used as the foaming agent. As the hydrocarbon having 2 to 8 carbon atoms, cyclopentane, propane, butane, n-
There are pentane, isopentane, neopentane, hexane, cyclohexane and the like. These may be a mixture of two or more. Cyclopentane is particularly preferred.

In addition, the following fluorinated halogenated hydrocarbons, other low-boiling halogenated hydrocarbons, and inert gases may be used in combination. The amount of the fluorinated halogenated hydrocarbon having an ODP of more than zero can be reduced in combination with the blowing agent in the present invention.

In the present invention, cyclopentane alone or a combination of cyclopentane and water is particularly preferred.

As the fluorinated halogenated hydrocarbon containing chlorine, R-123 (1,1-dichloro-2,2,2-
Trifluoroethane), R-141b, R-22 (monochlorodichloromethane), 1,2-dichloro-1,1,1
2-trifluoroethane (R-123a), 1-chloro-1,1-difluoroethane (R-142b), 3,3
-Dichloro-1,1,1,2,2-pentafluoropropane (R-225ca), 1,3-dichloro-1,1,1
2,2,3-pentafluoropropane (R-225c
b), 3-chloro-1,1,2,2-tetrafluoropropane (R-244ca), 1-chloro-1,2,2,2
3-tetrafluoropropane (R-244cb), 3-
Chloro-1,1,2,2,3-pentafluoropropane (R-235ca), 1,1-dichloro-1,2,2-
Trifluoropropane (R-243cc) and the like.

Examples of the fluorinated hydrocarbon containing no chlorine include 1,1,1,2-tetrafluoroethane (R-13).
4a), 1,1,1,4,4,4-hexafluorobutane (R-356mff), 1,1,1,2,3,3-hexafluorobutane (R-356mec), 1,1,
1,2,3,3-hexafluoro-2-methylpropane (R-356myp), 1,1,1,2-tetrafluoropropane (R-245eb), 1,1,2,2,3-
Pentafluoropropane (R-245ca), 1,1,
1,3,3-pentafluoropropane (R-245f
a), 1,1,1,3-tetrafluoropropane (R-
254fb).

The amount of the hydrocarbon having 2 to 8 carbon atoms is preferably 5 to 40 parts by weight, particularly preferably 10 to 30 parts by weight, per 100 parts by weight of the active hydrogen compound. The amount of water used is
0 to 5 parts by weight, based on 100 parts by weight of the active hydrogen compound,
Particularly, 0.5 to 3 parts by weight is preferable.

Examples of the polyisocyanate compound include aromatic, alicyclic and aliphatic polyisocyanates having two or more isocyanate groups and modified products obtained by modifying them. Specifically, tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate (commonly known as Crude MD)
I), polyisocyanates such as xylylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate, and modified prepolymers, nurates, and ureas thereof. Diphenylmethane diisocyanate, polymethylene polyphenylisocyanate and modified products thereof are particularly preferred.

A catalyst is used when reacting the active hydrogen compound with the polyisocyanate compound. As the catalyst, a metal compound catalyst such as an organotin compound which promotes a reaction between an active hydrogen-containing functional group and an isocyanate group, or an amine catalyst such as triethylenediamine can be used. A multimerization catalyst, such as a metal carboxylate, for reacting isocyanate groups can be used according to the purpose.

In addition, foam stabilizers for forming good cells are often used. Examples of the foam stabilizer include a silicone-based foam stabilizer and a fluorine-containing compound-based foam stabilizer. Other optional additives include, for example, fillers, stabilizers, coloring agents, and flame retardants.

Using these raw materials, polyurethane foam, urethane-modified polyisocyanate foam, and other foamed synthetic resins can be obtained. INDUSTRIAL APPLICABILITY The present invention is particularly useful in the production of rigid polyurethane foams and urethane-modified polyisocyanurate foams, which have hitherto been fields in which halogenated hydrocarbon-based blowing agents are frequently used. Especially, it is particularly useful in the production of a rigid polyurethane foam which is a heat insulating material for low thermal conductivity.

[0033]

The following examples (Examples 1 to 3) and comparative examples (Example 4)
The present invention will be specifically described with reference to (5), but the present invention is not limited to these examples.

According to the present invention, a rigid polyurethane foam was produced. The polyol used here is as follows.

(Polyol) A: 15% by weight of an oxyethylene group content (hereinafter referred to as EO content) obtained by polymerizing PO and then EO using 4,4'-diaminodiphenylmethane as an initiator, and a hydroxyl value of 5
Polyol having a viscosity of 3 × 10 ⁴ cP / 25 ° C. B: hydroxyl value 530 mg KO obtained by polymerizing PO using 4,4′-diaminodiphenylmethane as an initiator
H / g, viscosity 3 × 10 ⁴ cP / 25 ° C. polyol. C: EO content obtained by polymerizing EO and then PO using 4,4′-diaminodiphenylmethane as an initiator, an EO content of 15% by weight, a hydroxyl value of 420 mgKOH / g, and a viscosity of 4 × 10 ⁴
cP / 25 ° C. polyol.

D: Tolylenediamine as an initiator, PO
A polyol having a hydroxyl value of 350 mgKOH / g and a viscosity of 3 × 10 ⁴ cP / 25 ° C. obtained by polymerizing E: EO content obtained by polymerizing PO and then EO using bisphenol A as an initiator, an EO content of 40% by weight, and a hydroxyl value of 250
A polyol having a mgKOH / g viscosity of 8 × 10 ³ cP / 25 ° C. F: a polyol having a hydroxyl value of 420 mgKOH / g and a viscosity of 9 × 10 ³ cP / 25 ° C., obtained by polymerizing PO using sucrose / glycerin as an initiator.

G: E obtained by polymerizing PO and then EO using sucrose / monoethanolamine as an initiator
A polyol having an O content of 5% by weight, a hydroxyl value of 500 mgKOH / g, and a viscosity of 1.7 × 10 ³ cP / 25 ° C. H: hydroxyl value 500 mgKOH / g, viscosity 5 × obtained by polymerizing PO using monoethanolamine as an initiator
10 ² cP / 25 ° C. polyol.

(Examples 1 to 5) 2 parts of a silicone-based foam stabilizer, 100 parts by weight of an amine-based catalyst, 1 part of water, 1 part of water and cyclopentane per 100 parts by weight (hereinafter referred to as "parts") of a polyol mixture shown in the table Was mixed in the number shown in the table to obtain a system liquid. The system liquid was mixed with crude MDI at a liquid temperature of 20 ° C. so that the index would be 115, and 450 mm × 4
It was put into a 50 mm × 50 mm height aluminum mold and foamed. A sample of an appropriate size was cut out from the foam, and the overall density and the thermal conductivity were measured.
The results are shown in the table.

[0039]

[Table 1]

[0040]

EFFECT OF THE INVENTION By using a blowing agent having a low ozone depletion potential,
A rigid polyurethane foam having low thermal conductivity can be obtained.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C08G 101: 00) C08L 75:04

Claims (3)

[Claims] A hard foam synthetic resin obtained by reacting an active hydrogen compound having two or more active hydrogen-containing functional groups capable of reacting with an isocyanate group with a polyisocyanate compound in the presence of a blowing agent, a catalyst and other auxiliaries. Using a hydrocarbon having 2 to 8 carbon atoms or water as a foaming agent, and using an alkylene oxide adduct of diaminodiphenylmethanes or polymethylenepolyphenylamines as at least a part of the active hydrogen compound. A method for producing a rigid foamed synthetic resin. 2. The method according to claim 1, wherein the diaminodiphenylmethanes or polymethylene polyphenylamines are compounds represented by the formula (1). Embedded image In the formula (1), R is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and a plurality of Rs may be the same or different. n is an integer of 0-4. 3. The method according to claim 1, wherein the hydrocarbon having 2 to 8 carbon atoms is cyclopentane.