JPH09302129A - Production of rigid polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To practically obtain a stable rigid polyurethane foam free from dropping down of the resin, shrinking, the breaking out of cracking, etc., especially in execution ion freeze-up season of the atmosphere <=0 deg.C, even though the formulation using blowing agent which is a liquid at normal temperature and normal pressure in combination with a foaming agent which is a gas at normal temperature and normal pressure. SOLUTION: In the sigid urethane foam consisting of the reaction product of a polyol and an isocyanate in the presence of a catalyst blowing agent, a foam stabilizer, other auxiliary agent, the blowing agent which is a liquid at normal temperature and normal pressure is used on combination with a flowing agent which is a gas at normal temperature and normal pressure and the gaseous foaming agent is a fluorine containing compound having boiling temperature <=0 deg.C and having ozone depletion coefficient of 0 and the amount of this gaseous foaming agent is 1 to 10wt.% based on the weight of the polyol component and polyisocyanate compound.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a rigid polyurethane foam or a polyisocyanurate-modified polyurethane foam (hereinafter simply referred to as a rigid polyurethane foam) which is mainly used as a heat insulating material or the like.

[0002]

2. Description of the Related Art Rigid polyurethane foam is widely used as a heat insulating material for houses, refrigerators and the like because of its good heat insulating property and self-adhesive property. This rigid polyurethane foam is generally produced by mixing and stirring a polyhydroxy compound and a polyisocyanate compound together with a catalyst, a foaming agent, a foam stabilizer, and other auxiliaries, and reacting them in the presence of bubbles. I have. Then, as the foaming agent in this case, the boiling point and the low thermal conductivity from the advantage that the around room temperature, have predominantly (at most F ₁₁₎ trichloromonofluoromethane is used.

[0003] However, this F ₁₁ is made clear that adverse effects on the atmospheric environment of the earth's ozone layer destruction,
It is completely abolished by the end of 1995 as a regulated substance. Chlorofluorocarbon represented by F ₁₁ (hereinafter referred to as CF
It is said that C is a structure that does not contain hydrogen atoms in the molecule, is difficult to decompose because it is chemically stable, and is decomposed for the first time in the stratosphere, and the chlorine generated there destroys ozone.

As a means for completely eliminating F ₁₁ , it is general to use water in combination as a foaming agent and utilize carbon dioxide gas generated by the reaction between water and a polyisocyanate compound.
The thermal conductivity of the carbon dioxide gas is relatively high, more diffuse carbon dioxide into the atmosphere from the form, it is easy to replace the air, heat insulation, by such dimensional stability become poor, all the F ₁₁
It is considered difficult to replace carbon dioxide with carbon dioxide with the current technology.

[0005]

As an alternative substance for such CFC, hydrochlorofluorocarbon (hereinafter referred to as HCFC) or hydrofluorocarbon having a structure containing one or more hydrogen atoms in the molecule so as not to easily destroy the ozone layer. (HFC) is under development, and it is a social demand to manufacture rigid polyurethane foam using these. In response to the above-mentioned social demands, an example of using dichloromonofluoroethane (hereinafter referred to as 141b), which is HCFC, which is relatively easy to use in obtaining a rigid polyurethane foam in that it is difficult to destroy the ozone layer, is a conventional example. More suggested. However, one of HCFC, which is an alternative substance of F ₁₁ , 141 b has a boiling point of F ₁₁
It is about 8 ° C higher than the above and its solubility in polyol is too strong, so that it has a great influence on the reactivity and the manufacturing technical characteristics of the rigid polyurethane foam as compared with the case where F-11 was mainly used so far. There is a possibility.

[0006] For example, in the spray field in which hard polyurethane foam is sprayed directly on the wall surface or ceiling at a construction site such as an apartment house or an office building, particularly in construction at low temperatures in winter, heat is applied to the outside air and the body surface. Since it is easy to be robbed, the reaction is difficult to proceed and the liquid drops or peels off immediately after spraying,
Alternatively, there arises a problem that the thickness of the foam decreases or shrinks. Particularly in construction in a severe cold environment such as Hokkaido, not only liquid sagging and thickness reduction of the foam but also contraction in the width direction may occur, and sometimes the foam may crack.

In order to solve such a problem, Japanese Patent Publication No. 62-25430 proposes to use a specific amount of a gas compound as a foaming agent at room temperature and atmospheric pressure together with a foaming agent which is liquid at room temperature and atmospheric pressure. ing. However, in this proposal as well, when the ambient temperature is 0 ° C. or lower, depending on the type and amount of the isocyanurate-modified rigid polyurethane foam in which the reaction is difficult to proceed or the gaseous foaming agent used, the reactivity delay and the Problems such as liquid sagging, peeling, foam shrinkage, and cracks cannot be said to have been fully solved, and in practice, construction in such a low temperature environment is quite difficult. It is the current situation.

The present invention has been made in view of the above circumstances, and in a method for producing a rigid polyurethane foam, in a formulation using a gas foaming agent under normal temperature and normal pressure in combination with a liquid foaming agent under normal temperature and normal pressure. , Especially when the ambient temperature is 0
Even in construction under severe cold conditions of ℃ or below, the reactivity is still slow as described above, and overcoming the problem that construction is actually difficult due to liquid sagging, shrinkage, cracks, etc., resulting in It is an object of the present invention to provide a production method capable of practically obtaining a stable rigid polyurethane foam with less shrinkage and generation of cracks.

[0009]

The method for producing a rigid polyurethane foam according to claim 1 of the present invention comprises reacting a polyol and an isocyanate in the presence of a catalyst, a foaming agent, a foam stabilizer and other auxiliaries. In a rigid polyurethane foam, a liquid foaming agent under normal temperature and normal pressure and a gas foaming agent under normal temperature and normal pressure are used together, and the gas foaming agent under normal temperature and normal pressure is a fluorine compound having a boiling point of 0 ° C. or lower, and It is a compound having an ozone depletion potential of 0, and further, that the gas blowing agent at room temperature and normal pressure is used in the range of 1 to 10% by weight based on the total weight of the polyol component and the polyisocyanate component. Characterize.

A rigid polyurethane foam according to a second aspect of the present invention is characterized in that the rigid urethane foam described above is obtained by airless spray blowing foaming.

That is, the gist of the present invention is to obtain a rigid polyurethane foam by reacting a polyol and a polyisocyanate in the presence of a catalyst, a foaming agent, a foam stabilizer, and other auxiliaries, or to manufacture the same. , Under the conditions of using at least a fluorine compound as a liquid foaming agent under normal temperature and pressure,
A fluorine compound having a boiling point of 0 ° C. or less and having an ozone depletion potential of 0 as a gas blowing agent at room temperature and atmospheric pressure is used in an amount of 1 to 10 with respect to the total weight of the polyol component and the polyisocyanate component. The present invention relates to a method for producing a rigid polyurethane foam characterized by being used in a range of wt%, and further characterized in that the method for producing the rigid polyurethane foam is by airless spray blowing foaming.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

First, the polyol which can be used in the present invention is not particularly limited, and for example, it is obtained by ring-opening addition polymerization of glycerin, pentaerythritol, sucrose, ethylenediamine and the like with alkylene oxide such as ethylene oxide and propylene oxide. There are polyester polyols obtained by polycondensation reaction of ether polyols, polybasic acids such as phthalic acid, adipic acid and succinic acid with polyhydroxyl compounds such as ethylene glycol and propylene glycol, or ring-opening polymerization of lactones. Each can be used alone, or two or more kinds can be freely used in combination. However, in the case of airless spray blowing foaming, since it is required to foam and cure instantly, it is preferable to use a polyether polyol containing a compound having a high self-activity such as ethylenediamine as an initiator.

Next, hydrochlorofluorocarbons such as HCFC-141b and HFC-245f are used as a foaming agent which is liquid at room temperature and atmospheric pressure in the present invention.
Hydrofluorocarbons such as a, fluorine compounds represented by hydrofluoroethers such as HFE-347, water that reacts with isocyanate to generate carbon dioxide, or hydrochlorocarbons such as methylene chloride, cyclopentane, etc. And the like, which may be used alone or in admixture of two or more. The amount of the liquid foaming agent used at room temperature and atmospheric pressure is arbitrarily determined by the density of the desired foam, but is usually 10 to 80 parts by weight, particularly 100 parts by weight of the total polyhydroxy compound, 20 to 70 parts by weight is preferable.

[0015] Further, those used as a blowing agent in gaseous at normal temperature and pressure, a boiling point of fluorine-based compound is 10 ° C. or less, and those ozone destroy coefficient of 0, for example, H
There are hydrofluorocarbons such as FC-134a and HFC-236ea, which can be used alone or in admixture of two or more. The amount of such foaming agent used is 1
If it is less than 10% by weight, the effect for preventing the phenomenon such as shrinkage and peeling of the foam is insufficient, while 15% by weight
When it exceeds, the vaporization power is too strong and the foaming becomes unstable, so that a good foam cannot be obtained. The amount of the foaming agent used in the present invention is 1 to 10% by weight, preferably 2 to 8% by weight, based on the total weight of the polyol component and the isocyanate component.

Examples of the catalyst include organometallic compounds such as dibutyltin dilaurate, lead octoate and stannas octoate, amine compounds such as triethylenediamine and tetramethylhexamethylenediamine, and the like, usually in the field of urethane foams. There is no particular limitation as long as it is used in the above, and isocyanurate modification of N, N ', N "-tris (dimethylaminopropyl) hexahydro-s-triazine, potassium acetate, potassium octylate, etc. What is used can also be used.

As the foam stabilizer, a rigid polyurethane foam is used.
Anything that is effective for the production of aluminum can be used. For example, polyoxyalkylene-based compounds such as polyoxyalkylene alkyl ethers and silicone-based compounds such as organopolysiloxane can be used in usual amounts.

Further, in the present invention, any component other than the above, such as a filler and a flame retardant, can be used within the range not impeding the object of the present invention.

The polyisocyanate compound usable in the present invention is diphenylmethane diisocyanate.
And aromatic isocyanates such as tolylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate. And their crude products can be used.

Polyisocyanate based on the total amount of polyol
The amount of resin used, that is, the isocyanate index, is 80 to 130 when a conventional rigid polyurethane foam is produced.
When producing an isocyanurate-modified hard urethane foam, the range of 150 to 350 is preferable.

From the above raw materials, rigid polyurethane foam
When producing a film, it can be applied to any of in-situ foaming, injection, lamination and the like. As an example, a method for in-situ foaming will be described. An airless mixing type high-pressure spray foaming machine is used to prepare a component A mixed solution shown in Table 1, and this is mixed with polyisocyanate at high pressure in a mixing head. At this time, as a method for mixing the low-boiling-point blowing agent and other components, at this time, a method of directly mixing in a mixing head or a conduit from other components to the head, or before mixing at the mixing head Pre-mixing or the like in which other components such as a polyhydroxy compound component are mixed in advance can be employed.

[0022]

EXAMPLES Hereinafter, the present invention will be described more specifically based on examples and comparative examples, but the present invention is not limited to these examples. In addition, according to the formulation shown in Table 1, first, the component A mixture liquid was prepared to prepare three components of the mixture liquid A, polyisocyanate, and foaming agent-F. Next, a gasmer model FF unit (manufactured by Gasmer) was used as an airless mixing type high-pressure spray foaming machine system, the compounding liquid A and the polyisocyanate component were pressure fed from the main pump, and the foaming agent F was pressure fed from the subunit pump. Vertical
910mm, 1820mm wide, 5mm thick calcium silicate board-
Spray-blowing was performed at room temperature of 15 to -10 ° C. The temperature of the blended liquid in the foaming machine is set to 40 ° C,
The air pressure of the air pump was 5 kg / cm ² . The hard polyurethane foam has a spraying thickness of 5 to 10 mm per layer.
Placed three times and stacked. The results are shown in the examples.

[0023]

[Comparative Example] HCFC is a fluorine compound having a boiling point of 0 ° C. or less, but having a ozone depletion potential of not 0.
In the case of using 3% by weight of -22 (Comparative Example 1), in the case of using 3% by weight of CFC-12, which is a fluorine compound having a boiling point of 0 ° C. or less but having a large ozone depletion property (Comparative Example 2), A rigid polyurethane foam was obtained in the same manner as in the examples according to the formulation shown in Table 1 in the case where a gas blowing agent was not used at room temperature and atmospheric pressure (Comparative Example 3).

[0024]

[Table 1]

The following components were used as the compounding ingredients in Table 1. Polyol A: Toho Rika Kogyo Co., Ltd., isophthalic acid / terephthalic acid based polyester polyol Polyol B: Takeda Yakuhin Kogyo Co., Ltd., polyether polyol "GR-07" (ethylenediamine base polyol: average molecular weight 290 to 290) 300) Flame retardant: manufactured by Stoffer Japan Co., Ltd., Tris monochloropropyl phosphate "Phiroll PCF" Foam stabilizer: manufactured by Nippon Unicar Co., Ltd., silicone manufacturing agent "L-5420" Catalyst A: Nippon Kagaku Sangyo ( Co., Ltd., DO of lead octylate
P Solution (Lead Concentration 17%) Catalyst B: Kao Corporation, Tetramethylhexamethylenediamine "Kaolizer NO.1" Catalyst C: Nippon Kagaku Sangyo Corporation, 2-ethylhexylate potassium "B-15G" Polyisocyanate: Sumitomo Bayer Urethane Co., Ltd., crude diphenylmethane diisocyanate Blowing agent: Daikin Industries, Ltd. dichloromonofluoroethane “Daiflon 141b” Blowing agent F: Mitsui DuPont Fluorochemicals Ltd.,
"Suva 134a": (Ozone depletion potential (ODP) =
0) Foaming agent F: manufactured by Mitsui DuPont Fluorochemical Co., Ltd.
"Freon 22": (Ozone depletion potential (ODP) = 0.
02) Foaming agent F: manufactured by Mitsui DuPont Fluorochemical Co., Ltd.
"Freon 12": (Ozone depletion potential (ODP) = 1)

The evaluation methods for the foams shown in Table 1 were as follows. (1) Spray Atomization Width (cm) A urethane foam stock solution was spray-foamed onto a calcium silicate plate having a spray nozzle installed directly below about 1 m above the ground, and the atomization width of the obtained foam was measured. (2) Peeling off the foam As in (1), spray the urethane foam stock solution onto the calcium silicate board using a spray nozzle, observe the cross section of the foam after foaming, and peel off between the body and the foam or foam lamination. Check for. (3) Shrinkage in the thickness direction The shrinkage in the thickness direction is the thickness in the thickness direction immediately after the foam is obtained by spraying the calcium silicate plate.
The dimensional change rate of the thickness in the thickness direction was measured 1 hour after the construction. (4) Shrinkage in the width direction A hard polyurethane foam sprayed on a calcium silicate plate is cut into a size of 100 mm width × 100 mm with the thickness kept, and left in an environment of −15 ° C. for 24 hours, and the front and rear width directions. The dimensional change rate was measured. (5) Foam density The spraying thickness is about 15 to 20 mm per layer, and 3
~ 4 times lamination to make a sample for density measurement, JIS
-Measured according to A9514. The cutting was performed so as to include one skin layer.

As a result, when a hydrochlorofluorocarbon such as HCFC-22 is used as a gas blowing agent at room temperature and normal pressure, the shrinkage rate is insufficiently suppressed, and CFC-1 is used.
When a chlorofluorocarbon such as 2 is used, the shrinkage rate is suppressed, but ozone depletion is great and it is not recommended. On the other hand, in the examples, by using an appropriate amount of a fluorine-based compound that does not destroy the ozone layer as a gas foaming agent at room temperature and atmospheric pressure, workability is good even in a severe cold environment, and the shrinkage rate is reduced despite the lower density. An excellent rigid polyurethane foam with suppression is obtained.

[0028]

As described above in detail, according to the method for producing a rigid polyurethane foam of the present invention, a foaming agent that is liquid at normal temperature and normal pressure is used in combination to foam a gas at normal temperature and normal pressure. By using a fluorine-based compound that does not destroy the ozone layer as an agent, it is possible to obtain an excellent rigid polyurethane foam that has excellent workability even in a harsh cold environment and that suppresses shrinkage, and its practical utility value in industry is extremely high. Will be things.

Claims (2)

[Claims] 1. A catalyst comprising a polyol and an isocyanate,
A foaming agent, a foam stabilizer, and a rigid urethane foam obtained by reacting in the presence of other auxiliaries, using a liquid foaming agent under normal temperature and normal pressure and a gas foaming agent under normal temperature and normal pressure, and under the normal temperature and normal pressure. The gas blowing agent is a fluorine compound having a boiling point of 0 ° C. or less and an ozone depletion potential of 0, and further, the gas blowing agent under normal temperature and pressure is
A method for producing a rigid polyurethane foam, which is used in the range of 1 to 10% by weight based on the total weight of the polyol component and the polyisocyanate component. 2. The method for producing a rigid polyurethane foam according to claim 1, wherein the rigid polyurethane foam is produced by airless spray blowing foaming.