JPS58134109A - Production of rigid polyurethane foam - Google Patents

Abstract

PURPOSE:To reaction between a mixed polyol consisting of a specific aromatic polyol and other polyols and an aromatic polyisocyanate is carried out in the presence of a catalyst and a halogenated hydrocarbon foaming agent to produce the titled foam with improved insulation properties. CONSTITUTION:The reaction between an aromatic polyisocyanate and a polyol mixture with average hydroxyl value of 300-650 consisting of (A) 20-100wt% of polyol terminally capped with ethylene oxide (0.02-2 molecules of ethylene oxide is used for terminal capping), which is obtained by adding 1.2-4.0 molecules, on the average per an active hydrogen, of alkylene oxides (consisting of 0.5-3.5 moles of ethylene oxide and 0.5-3.5 moles of propylene oxide on the average per above active hydrogen stom) to an aromatic polyamine and has an average hydroxyl value of 200-550 and of (B) 80-0wt% of polyols other than component A is carried out in the presence of a catalyst and a halogenated hydrocarbon foaming agent to give the objective foam.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a rigid polyurethane foam with improved heat insulation properties, and in particular, a method for producing a rigid polyurethane foam using an aromatic polyol terminal-capped with ethylene oxide. be.

It is known to produce rigid polyurethane foam by reacting an aromatic polyol obtained by adding an alkylene oxide such as ethylene oxide or propylene oxide to an aromatic polyamine and an aromatic polyinsyanate in the presence of a blowing agent and a catalyst. Yes, for example, Tokko Sho 3
9-22617 Publication J Special Publication No. 4B-52597, Publication No. 49-28038, Publication No. 51-867
6, Special Publication No. 16480, Special Publication No. 16480, Special Publication No. 16480
It is described in, for example, Japanese Patent No.-32327. Typical aromatic polyamines include tolylene diamine and aniline-formaldehyde condensate (for example, 4,4'-diaminodiphenylmethane). It is said that this aromatic polyol has a relatively high affinity with aromatic polyinsyanate, thereby providing a good foam. Rigid polyurethane foams are often manufactured using a one-shot process. In particular, the most common method is the one-shot method in which a rigid polyurethane foam is produced by mixing two liquids: a polyol component in which a blowing agent and a catalyst are mixed with a polyol, and a polyinsyanate component in an aromatic polyinsyanate.

The first rigid polyurethane foam used as insulation material
The required physical properties are high heat insulation, that is, high thermal conductivity. The M11 thermal properties of rigid polyurethane foam are related to the type of gas inside the cells (i.e. the type of blowing agent) and the material of the polyurethane itself such as the cells and walls, but the size of the cells and their uniformity also affect the heat insulation properties. There is an impact.

In recent years, with the promotion of resource and energy conservation, the density of rigid polyurethane foam has been reduced, but the problem is that this reduction in density tends to cause non-uniformity in the size of the cells in the rigid polyurethane foam. There is one. The present inventor found that increasing the uniformity of the cell size of rigid polyurethane foam is effective in improving heat insulation properties, and conducted studies to find a new aromatic polyol for this purpose.

On the other hand, polyols for rigid polyurethane foams also have performance requirements for physical properties other than heat insulation and physical properties required for handling the polyol. One of them is the compatibility of polyols with other raw materials. As mentioned above, polyol components in which blowing agents, catalysts, and usually foam stabilizers are added to polyols in advance can cause various problems such as phase separation and clouding if the affinity between the polyol and these additives is too low. easy. Generally, many of these additives are hydrophobic and have low affinity with highly hydrophilic polyols. Among the oxyalkylene groups in aromatic polyols, oxyethylene groups are hydrophilic and oxypropylene groups are hydrophobic. Therefore, polyols with too many oxyethylene groups may be difficult to handle or the physical properties of the resulting foam. It is thought that this can easily cause problems. On the other hand, the viscosity of aromatic polyols is lower as the number of oxyethylene groups increases.
As shown in Japanese Patent No. 2327, when the same oxyethylene group and oxypropylene group are present, the aromatic polyamine to which the oxyethylene group is first bonded has a lower viscosity. The viscosity of the aromatic polyol is not often considered important in its handling, and if possible, one with a lower viscosity is preferred.

The present inventor investigated various aromatic polyols with the aim of improving the uniformity of the cells in the rigid polyurethane foam, particularly making them smaller and with less change in diameter. It has been found that aromatic polyols with oxyethylene groups and so-called terminal ethylene oxide camps can achieve this purpose.

This aromatic polyol preferably has a certain amount or more of oxypropylene groups in order to solve the above-mentioned affinity problem, and furthermore, in consideration of the viscosity problem, it preferably has oxyethylene groups at non-terminal positions as well. The present invention is a method for producing rigid polyurethane foam using an aromatic polyol whose ends are capped with ethylene oxide. This aromatic polyol is 2% of the total polyol used.
It is used in an amount of 0 to 100% by weight, preferably 40 to 90% by weight, and the average hydroxyl value of the polyol containing this aromatic polyol is 300 to 650. That is, the present invention provides a method for producing rigid polyurethane foam by reacting a polyol with an average hydroxyl value of 300 to 650 and an aromatic polyinsyanate in the presence of a halogenated hydrocarbon blowing agent or catalyst. 6
50 polyol is composed of an average of 20 to 100% by weight of hydroxy acid and 0 to 80% by weight of a polyol other than the aromatic polyol below, and the aromatic polyol is added to an aromatic polyamine with an average of 1% by weight per active hydrogen of the aromatic polyamine. It is a terminal ethylene oxide-capped polyol obtained by adding 2 to 4 molecules of alkylene oxide, and the alkylene oxide has an average of 05 to 5.5 molecules of ethylene oxide and 0.5 to 55 molecules of ethylene oxide based on the active hydrogen. This is a method for producing a rigid polyurethane foam, characterized in that propylene oxide is used, and o.2 to 2 molecules of ethylene oxide are used for end capping. Mononuclear or polynuclear aromatic dilyamine can be used as the aromatic polyamine. A typical mononuclear aromatic polyamide is tolylene diamine. For trilene needle thymine, 2.6
body, 2.4 body, 2.5 body, 2.6 body, 3.4 body and 3
．． There are six types of isomers, and any of the six isomers can be used, or a mixture of two or more types of isomers may be used.

Preferred tolylene diamines are tolylene diamines containing 2.4-isomer, 2.6-isomer and mixtures thereof, and 2,3-isomer, 3.4-isomer and mixtures thereof as main components.

Representative polynuclear aromatic polyamines are polymethylene polyphenylamines obtained by condensation of aniline and formaldehyde, particularly diaminodiphenylmethanes such as 4,4'-diaminodiphenylmethane. This polymethylene polyphenylamine may be a single compound or a mixture of various compounds. Other aromatic polyamines include
There are diaminobenzene, naphthalenediamine, diaminodiphenyl ether, and compounds having two or more amine groups in their respective groups or different aromatic nuclei. The hydrogen atoms bonded to the nitrogen atoms of these amino groups may be partially substituted with lower alkyl groups, etc., but in that case, the number of hydrogen atoms bonded to the nitrogen atoms of the aromatic polyamine is one molecule. On average, we need about 3 or more. Further, the aromatic polyamine may have other active hydrogen-containing groups (eg, hydroxyl groups). Preferred aromatic polyamines are tolylene diamine, diaminodiphenylmethane, and a polymethylene polyphenylamine mixture containing diaminodiphenylmethane as a main component. Particularly preferred are single compounds of tolylene diamine and mixtures of various dolylene diamine isomers.

Aromatic polyols are produced by adding alkylene oxide to the above-mentioned aromatic polyamines.

The alkylene oxide may be ethylene oxide or propylene oxide, and the aromatic polyol is produced by adding both of them sequentially or as a mixture to an aromatic polyamine, and then adding ethylene oxide as a terminal cap. Add ethylene oxide and propylene oxide in this order. It is preferable to do this, and it is also possible to repeat these two sequential additions two or more times. Similarly, propylene oxide and ethylene oxide can be added sequentially in this order, but the resulting aromatic polyol will usually have a somewhat higher viscosity than that obtained in the former case. In any sequential addition, the final ethylene oxide addition following the propylene oxide addition is the end-camping operation. The desired aromatic polyol can be obtained by adding a mixture of ethylene oxide and propylene oxide to an aromatic polyamine, and then adding ethylene oxide as a terminal camp. The viscosity in this case often shows a viscosity between the former two sequential additions. In addition, in the case of mixed addition, a mixture of ethylene oxide and propylene oxide and ethylene oxide or propylene oxide can be sequentially added, and mixtures of ethylene oxide and propylene oxide having different compositions can also be sequentially added. The aromatic polyol obtained by adding propylene oxide to an aromatic polyamine and then capping the end with 1° ethylene oxide tends to have the highest viscosity, so a relatively small amount of it is combined with a large amount of other low-viscosity polyol. It can be used when The high and low viscosities of these polyols are usually the same when ethylene oxide and propylene oxide are added in approximately the same proportions, and if they are different, the order of viscosity can vary greatly.

The amount of alkylene oxide added to the aromatic polyamine refers to the average number of molecules added per hydrogen atom (hereinafter referred to as active hydrogen) with which the alkylene oxide of the aromatic polyamine can react. For example, tolylenediamine and 4.4
'-Diaminodiphenylmethane has four active hydrogen atoms (hydrogen atoms of amine group) in one molecule, and the number of molecules added per active hydrogen atom is μ of the number of alkylene oxide molecules added to one molecule of these aromatic polyamines. This value corresponds to the number of moles of alkylene oxide added to one mole of these aromatic polyamines. For aromatic polyamines:・:):.

The total amount of alkylene oxide added is 1.2 to 4.0 molecules, and the alkylene oxide consists of 0.5 to 55 molecules of ethylene oxide and 05 to 5 molecules of propylene oxide. The 002 to 2.0 molecules in the ethylene oxide were used for end capping. For example, if X molecules of ethylene oxide, 7 molecules of propylene oxide, and 2 molecules of ethylene oxide (x, y, and Z are the average number of added molecules per active hydrogen) are added to an aromatic polyamine in this order, the respective ranges is 0≦X≦3
．． 1.05≦y≦3.5゜002≦2≦2.0. And 0
．． 5≦X+Z≦3,5゜12≦x + y + 'z≦
4.0 is preferred. The total number of alkylene oxide molecules added is preferably 1.5 to 3.5, most preferably 1.8 to 52. Among them, 1.
0-3.0. Preferably propylene oxide 05-2.0, most preferably ethylene oxide 1.2-2.5,
Propylene oxide is 06-1.8. Of the ethylene oxide, ethylene oxide for end cap is 0.
1 to 1.5 is preferred, particularly preferably 02 to 1.0. In this case, the ethylene oxide for the non-terminal cap is preferably at least 0.5 or more, particularly preferably 08 or more. In the above sequential addition method, 0.5≦X≦2.5, 0.5≦y≦
2, O, 0, 1≦2≦1,5 and 1.0≦X+Z≦3
．． 0,1.5≦X+7-1-Z≦&5 is preferable, especially 08≦X≦2.0.0.6≦y≦1.8. [1,2≦2
≦1.0 and 1.2≦X+Z≦2.5, 1.8≦x
+ y + Z≦'5.2 is preferred. Even in sequential addition or mixed addition other than this sequential addition, the amount of ethylene oxide for the end cap is preferably within the above range, and the amounts of other alkylene oxides are also preferably within the above range.

End-capping with ethylene oxide increases the proportion of primary hydroxyl groups in the aromatic polyol. The proportion of primary hydroxyl groups in the polyol before end-capping Fio ~ 50%,
Particularly preferred is 0 to 30 inches. The proportion of primary hydroxyl groups after end-capping is preferably 5 to 100%, particularly preferably 5 to 60%.

In particular, it is preferable that the value of the primary hydroxyl group before end-capping is 5 or more, particularly 20 or more, which is a large value of 4. Average of 1 per active hydrogen
If the ethylene oxide of the molecule is end-capped, the proportion of primary hydroxyl groups will be 0%, but this is not the case if non-uniform addition occurs; The ratio of hydroxyl groups is often less than 100.Ethylene oxide for purposes other than end capping is at least 0.1% per active hydrogen as mentioned above.
It is preferable to use at least 0.4 molecules, especially at least 0.4 molecules. It is preferred that part or all of the ethylene oxide, preferably up to 1.5 molecules, especially up to 1.2 molecules, be added directly to the aromatic polyamine. The reason for this is that, as mentioned above, by first adding ethylene oxide to the aromatic polyamine, the viscosity of the aromatic polyol can be significantly lowered. □ The aromatic polyolnohydroxyl value obtained as described above ranges from 20.□10□1' to 550.

On the other hand, in order to obtain a good rigid polyurethane foam, the average hydroxyl value of the polyol used is usually 300 to 6.
50, and therefore a low hydroxyl value aromatic polyol is used in combination with another high hydroxyl value polyol. Although the aromatic polyol having a high hydroxyl value can be used alone, it is preferable to use it in combination with other polyols in order to lower the viscosity or further improve the foam properties. The proportion of the aromatic polyol in the above polyol having an average hydroxyl value of 300 to 650 is 20 to 100% by weight, preferably 40 to 90% by weight, particularly preferably 40 to 70% by weight. %.

Examples of polyols used in combination with the aromatic polyols mentioned above include those disclosed in Japanese Patent Publication No. 49-28038 and Japanese Patent Publication No. 5
There are various polyols that can be combined with the aromatic polyol described in Japanese Patent No. 6-32327. The polyol is preferably a polyether polyol, a polyester polyol, a polyhydric alcohol, an alkanolamine, etc. The hydroxyl value thereof is preferably 200 or more, particularly 300 or more, and the number of hydroxyl groups is 2 or more, especially 2
-8 is preferable. These polyols can be used in combination of two or more types, and may also be a mixed polyol obtained by adding an alkylene oxide to a mixture of two or more types of initiators. This polyol may be a polyol having an aromatic nucleus other than the aromatic polyol obtained by adding an alkylene oxide to an aromatic polyamine as described above. Examples of polyols having aromatic nuclei include polyether polyols obtained by adding alkylene oxide to polyhydric phenols such as bisphenol A and novolanc, and polyols obtained from phthalic acid and other aromatic polycarboxylic acids and polyhydric alcohols. There are polyester polyols, etc. Polyols that can be used in combination with the aromatic polyol include the following, but are not limited to these, of course.

Polyhydric alcohols: ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, chrycerin, diglycerin, trimethylolpropane, hexanetriol, pentaerythritol Alkanolamines: jetanolamine, diimpropylene Tool amine, triethanolamine, amine-alkylene oxide adduct: ethylenediamine'-alkylene oxide adduct polyether polyol: polyhydric alcohol, alkanolamine, amine, polyhydric phenol, sugar alcohol (textulose, sucrose, glycoside, etc.) ), or mixtures thereof with alkylene oxides and other epoxides (styrene oxide, 4.4.4-)! 1,2-butylene oxide, etc.).

Polyester polyol: A reaction product of polybasic acid (phthalic acid, terephthalic acid, inphthalic acid, adipic acid, succinic acid, etc. or derivatives such as their anhydrides) and polyhydric alcohol.

Particularly preferred combinations are combinations of the above-mentioned aromatic polyols and low-viscosity, low-molecular-weight polyether polyols or polyhydric alcohols, and systems in which they are further combined with other polyether polyols or polyester polyols.

Examples of aromatic polyincyanates include tolylene diincyanate (TD process), diphenylmethane diincyanate (MDI), polymethylene polyphenylinocyanate (PAP process), naphthalene diincyanate, xylylene diincyanate, dianisidine diincyanate, etc. There is. Preferred ones are 2.4-) lylene diincyanate,! : 2.6-) A mixture of lylene diincyanate, 4.4'-diphenylmethane diincyanate, and polymethylene polyphenyl incyanate having an average functional group number of 2.2 to 4.0. So-called modified polyincyanates obtained by modifying these aromatic polyincyanates by various methods or compounds may also be used. The amount of aromatic polyisocyanate used is preferably 90 to 130, particularly 100 to 12
0 is preferred.

Rigid polyurethane foam is obtained by reacting the above polyol and aromatic polyinsyanate in the presence of a blowing agent and a catalyst. Furthermore, it is preferable to add a foam stabilizer to improve the uniformity of cells. Suitable blowing agents include trichlorofluoromethane, dichlorodifluoromethane, methylene chloride, other low-boiling halogenated hydrocarbons, or water. Preferred blowing agents are trichlorofluoromethane alone or in combination with water or dichlorodifluoromethane, and most preferred is a combination of trichlorofluoromethane and water. The amount of trichlorofluoromethane used is 100 kg of polyol.
? jL? . Appropriate amounts are 9□1゛, □Work□, and 6o to 60i parts. Similarly, the amount of water used is preferably from 11 to 5 parts by weight, particularly from 15 to 5 parts by weight.

Suitable catalysts include tertiary amine catalysts and M-welded compound catalysts, but are not limited to these. In addition, various types of silicone-based surfactants are commercially available as foam stabilizers, but they are also limited to these. There is no particular limitation on the amount of each used, but as above, the amount of catalyst used is 1
．． Suitable amounts are 0 to 10 parts by weight, and 01 to 5 parts by weight for the foam stabilizer. Other additives can also be added to the rigid polyurethane foam using these raw materials. For example, flame retardants, fillers, reinforcing fibers, stabilizers, etc.

As mentioned above, the one-shot method is suitable for producing the rigid polyurethane foam of the present invention.

However, the present invention is not limited thereto, and can also be produced by a quasi-prepolymer method, a prepolymer method, a spray method, or the like. The resulting rigid polyurethane foam is suitable as a variety of thermal insulation materials. For example, it is suitable as a heat insulating material for refrigerators, freezers, other electrical and mechanical appliances, and heat insulating panels used in architectural structures and automatic storage facilities.

EXAMPLES The present invention will be specifically explained below using Examples, but the present invention is not limited to these Examples.

Example 2: Preparation of polyols Various polyols were prepared by adding metatolylene diamine (m-TDA) or orthotolylene diamine (o-TDA) Ic to ethylene oxide (Eo) and propylene oxide (pc). In the following, T.D.
A+kl! :O+ mho + nEo indicates that 1 mole of tolylene diamine was first added with moles of EO, then -m moles of PO, and finally capped with n moles of EO. Also, l/po indicates that they were used in combination. The hydroxyl value of the obtained polyol (0
) (V), viscosity at 25°C (η), primary hydroxyl group (
1°O'H), and the numbers in brackets before it indicate the respective numbers before the last KO cap. Also,
Diluents and additional polyols are also common.

Polyol A: m-TDA+ 4KO+ 4PO+
2BOCOHV = 420, η = 1.6
X 10'cp, 1°OH-〇%] 0HV=360. η=1. lX10'cp,
1°0H=40% Polyol B: m-TDA+511! O+ 3PO
+ I TLO[0HV=41. η=1. OX
10'cp, 1° 0H = 15ch] 0HV = 400.1 = n, 8X 10'cp, 1°
0H=40 Thipolyol O: m-TDA+2゜5 KO+ 3PO
+ 2 EO[0HV=540. η=! IX
105cp, 1°0H=0chi] 0HV=450.1 = 1.5X10'cp, 1°0
H=40% poly, t-ru D: m-TDA+ 2.11 KO
'+5PO+11.5 EO[0HV=450.
η= J X 10'cp, 1°OH-○
・1) OHV=430. η=36X10'cp, 1°OH
-5% Polyol E 2m-TDA+ 7 (go/coE) 0
1 molar ratio 1:1) OHV=405.7=2X10'cp
, 1°0H=30% Polyol F: m-TDA+7 (KO/'PO
,% ratio 0.5:1)+0.5KO OHV=445.1=5. XIQ'CI), 1°0H
=5% poly, t-/l, G: 0-TDA+2.5f
fiO+3PO+2 EO(OHV=550.+7
=2.2X105. 1°0H=0%] 0HV=460. η=1.0X10', 1°0
H=40% polyol H: 0-TDA+2EO+
5PO+ 0.5 EO (OHV=440. η=5.
2X10', 1°OH-04) OHV=420.
η=2.8X10', 1°0H-5% diluent a: 0
HV=475.1=60'cp tD low molecular weight polyether diol.

:・ Diluent b: 0HV=320',, η=60 cp
Low molecular weight, ms polyether diol.

Diluent c: 0HV=651], η=80 cp
(D low molecular weight polyether diol.

Diluent d: 0HV=500.1=60cp (D
Low molecular weight polyether diol.

Additional polyol: 0HV obtained by adding EO and PO to a mixture of sucrose and jetanolamine (molar ratio 1:6) = 5! +0. η= 1.6X 103cp (
D polyether polyol.

n. Preparation of rigid polyurethane foam A total of 100 parts by weight of the above A-H aromatic amine polyols, diluents a-a, and additional polyols (the composition is shown in the table), 1.5 parts by weight of water, and a silicone-based polyol. 1.5 parts by weight of foam stabilizer, catalyst (
4.5 parts by weight of a mixture of tetramethylhexamethylene diamine and pentamethyldiethylenetriamine in a weight ratio of 3:1) and 50 parts by weight of a trichlorofluoromethane blowing agent were mixed. Kyuruto MDI was mixed with this polyol component so that the incyanate index was 110, and the mixture was poured into a mold to produce a rigid polyurethane foam.

Table 1 below shows the composition, average hydroxyl value, and viscosity of the three-component polyol mixture, as well as the density (10 chip rate), K factor, compressive strength, closed cell ratio, and dimensions of the resulting rigid polyurethane foam. Indicates stability. In addition,
The K factor is a value measured by Anacon Model-88, and indicates the dimensional change rate in the thickness direction after 124 hours at 30° C. compared to the dimensional stability r.

Claims (1)

[Claims] 1. A method for producing a rigid polyurethane foam by reacting a polyol with an average hydroxyl value of 500 to 650 and an aromatic polyincyanate in the presence of a norogenated hydrocarbon blowing agent or catalyst. The polyol having a hydroxyl value of 300 to 650 is composed of 20 to 100% by weight of the following aromatic polyol having an average hydroxyl value of 200 to 550 and 0 to 80% by weight of a polyol other than the following aromatic polyol, and the aromatic polyol is It is a terminal ethylene oxide-capped polyol obtained by adding an average of 1.2 to 4.0 molecules of alkylene oxide per active hydrogen of the aromatic polyamine to an aromatic polyamine, and the alkylene oxide has an average of 0.2 to 4.0 molecules per active hydrogen of the aromatic polyamine. A rigid polyurethane comprising 5 to 5 molecules of ethylene oxide and 0.5 to 5 molecules of propylene oxide, of which 02 to 2 molecules of ethylene oxide are used for end capping. Method of manufacturing foam. 2. The method according to claim 1, wherein the end-capping ethylene oxide is used in an average amount of 0.2 to 1.5 molecules per active hydrogen of the aromatic polyamine. 6. The method according to claim 1, characterized in that ethylene oxide other than for end capping is used in an average amount of 0.5 or more molecules per active hydrogen of the aromatic polyamine. 4. The method according to claim 1, wherein the aromatic polyol is obtained by adding ethylene oxide, propylene oxide, and ethylene oxide to an aromatic polyamine in this order. 5. An average of 0.5 per active hydrogen in aromatic polyamine
~2.5 molecules of ethylene oxide, 0.5 to 2.0 molecules of propylene oxide, and 0.2 to 1.5 molecules of ethylene oxide (however, the total of ethylene oxide is 1
．． 0 to 3.0 molecules, total of fullkylene oxide is 1.5
3.5 molecules) in this order.