JP2000302832A - Rigid polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rigid polyurethane foam which solves the problem accompanying the use of hydrofluorocarbon as a foaming agent which does not cause the problem of ozone-layer destruction but hardly dissolves in polyol components and is hardly blended in a large amount, and exerts an excellent foam-forming ability, foam properties such as heat insulating property, etc., and applicability. SOLUTION: In a rigid polyurethane foam obtained by allowing a polyisocyanate component to react with a blend solution wherein a polyol component, a foaming agent, a catalyst, a foam stabilizer and other auxiliaries are mixed, a hydrofluorocarbon which is in a liquid state at an ordinary temperature and pressure and a hydrofluorocarbon which is in a gas state at an ordinary temperature and pressure are used as the foaming agent. Here, at least a portion of the hydrofluorocarbon which is in a liquid state at an ordinary temperature and pressure is mixed in the blend solution. When the blend solution is heated in a sealed vessel, the internal gauge pressure is 1.5 kg/cm2 or smaller when the liquid temperature is 60 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rigid polyurethane foam, and more particularly to foaming by mixing a polyisocyanate component with a compounded liquid obtained by mixing a polyol component, a foaming agent, a catalyst, a foam stabilizer and other auxiliaries. A rigid polyurethane foam to be formed.

[0002]

2. Description of the Related Art Rigid polyurethane foams are widely used as heat insulating materials for houses, refrigerators and the like because of their excellent heat insulating properties and self-adhesive properties.

[0003] Rigid polyurethane foams used in these applications are generally foamed by mixing a polyisocyanate component and a compounded liquid obtained by mixing a polyol component, a foaming agent, a catalyst, a foam stabilizer and other auxiliaries with a mixing head. In this method, a good heat-insulating layer of a rigid polyurethane foam can be formed by a simple operation of directly spraying and applying to an object to be applied.

On the other hand, as a panel material used for heat insulation and partitioning in a refrigerated / frozen warehouse or a clean room, a heat insulating panel has been developed in which a metal plate or a plywood for structure is used as a face material and a hard polyurethane foam having high heat insulating performance is sandwiched. Has been put to practical use.

[0005] Such a heat insulating panel using a rigid polyurethane foam as a heat insulating material is generally prepared by mixing a polyisocyanate component with a compounded liquid obtained by mixing a polyol component, a foaming agent, a catalyst, a foam stabilizer and other auxiliaries. It is manufactured by an injection molding method in which a rigid polyurethane foam raw material obtained by foaming is injected into a hollow portion of a hollow panel body having a hollow portion composed of a surface material and a side frame material and is integrally molded. Injection molding is widely used as a typical method for manufacturing heat-insulating panels using rigid polyurethane foam because the product dimensions can be arbitrarily designed, and since it can be molded integrally with the surface material and has high productivity. Have been.

For example, as a plate-like material used for heat insulation in a commercial warehouse or the like, a laminate board material obtained by laminating non-combustible paper or gypsum face material on hard urethane foam, a metal decorative face material, or a ceramic face material is used. There is a siding material and the like, such an insulation board,
Generally, a polyisocyanate component, a polyol component,
After mixing a foaming agent, a catalyst, a compounding solution prepared by mixing a foam stabilizer and other auxiliaries, and hard foam raw material obtained by foaming, a paper, a veneer plate, a metal plate, a gypsum board, etc. are laminated and molded. It is manufactured by a continuous foaming method of cutting into predetermined dimensions. A typical example of the molding method by continuous foaming is a double conveyor system in which a rigid polyurethane foam raw material is discharged from a mixing head onto a surface material sent out by a pair of upper and lower belt conveyors, and pressed and molded in a foaming process. According to this method, the dimensions of the product can be arbitrarily designed, and it can be integrally molded with the surface material in one step, and the productivity is high.

In rigid polyurethane foams, dichloromonofluoroethane, which has been conventionally used as a foaming agent, has a problem of destruction of the ozone layer. Therefore, in recent years, there has been no problem of destruction of the ozone layer as an alternative foaming agent. Hydrofluorocarbon (hereinafter abbreviated as "HFC")
Has been proposed.

It has also been proposed to use water as a foaming agent and utilize carbon dioxide gas generated by the reaction between water and a polyisocyanate compound.

[0009]

However, in the technique using only water as a foaming agent, the ozone layer is not destroyed, but the poor thermal conductivity of carbon dioxide gas, which is a disadvantage when water is used as a foaming agent, Alternatively, there has been a problem that the carbon dioxide gas easily diffuses from the foam into the atmosphere to be replaced with air, resulting in poor heat insulating properties and dimensional stability, and further, deterioration in adhesiveness.

In addition, HFCs having no problem of destruction of the ozone layer are difficult to dissolve in the polyol component, and even if they are liquid at normal temperature and normal pressure, the internal pressure of the compounded liquid increases, so that only a small amount can be mixed and used. . For this reason, the foaming amount is small and the foam cannot be reduced to a normal density level. Therefore, material costs rise and it is difficult to spread. The workability (spray pattern, reactivity) deteriorates due to an increase in the viscosity of the liquid mixture. Adhesion between layers is poor in spraying, and delamination occurs. There was such a problem.

The present invention solves such a problem when HFC is used as a foaming agent, and is excellent in foam forming properties, and therefore, is excellent in foam properties such as heat insulating properties.
An object of the present invention is to provide a rigid polyurethane foam excellent in workability.

[0012]

The rigid polyurethane foam of the present invention is obtained by reacting a polyisocyanate component with a compounded liquid obtained by mixing a polyol component, a foaming agent, a catalyst, a foam stabilizer and other auxiliaries. In the rigid polyurethane foam, a hydrofluorocarbon liquid at normal temperature and normal pressure and a hydrofluorocarbon gas at normal temperature and normal pressure are used as foaming agents, and at least a part of the hydrofluorocarbon liquid at normal temperature and normal pressure is mixed in advance with the compounded liquid. Wherein the internal pressure at a liquid temperature of 60 ° C. is a gauge pressure of 1.5 kg / cm ² or less when the compounded liquid is heated in a closed container.

In the present invention, HFC which is liquid at normal temperature and normal pressure is used as a foaming agent, and HFC which is gas at normal temperature and normal pressure used as a refrigerant of a refrigerator is used together. As a result, it is possible to suppress an increase in the internal pressure of the liquid mixture containing the liquid HFC at normal temperature and normal pressure. Even when only a small amount of liquid HFC can be mixed at normal temperature and normal pressure, the gaseous HFC can be mixed at normal temperature and normal pressure. , A good foam can be formed.

In the present invention, gaseous HF at normal temperature and normal pressure is used.
C is mixed with a polyisocyanate component and H
It is preferable to use 0.5 to 10% by weight based on the total weight of the mixed liquid excluding FC and HFC which is liquid at normal temperature and pressure.

As the HFC which is liquid at normal temperature and normal pressure,
1,1,1,3,3-pentafluoropropane is preferable, and HFC that is a gas at normal temperature and normal pressure is 1,1,1
1,2-tetrafluoroethane is preferred.

In the present invention, the mixture obtained by mixing the polyol component, at least a part of HFC liquid at ordinary temperature and pressure, a catalyst, a foam stabilizer and other auxiliaries has a viscosity at a liquid temperature of 20 ° C. It is preferably at most 500 cps.

Further, the rigid polyurethane foam of the present invention preferably has a core density of 20 to 40 kg / m ² .

Such a rigid polyurethane foam of the present invention is suitable for a rigid polyurethane foam obtained by airless spray foaming in which a polyisocyanate component and a blending solution are mixed and foamed by a mixing head. It is preferable to directly introduce and mix the gaseous HFC under pressure or the HFC gaseous at normal temperature and normal pressure and the HFC liquid at normal temperature and normal pressure into a mixing head or a conduit for other components leading to the mixing head.

[0019]

Embodiments of the present invention will be described below in detail.

In the present invention, when a rigid polyurethane foam is produced by reacting a polyisocyanate component with a liquid mixture obtained by mixing a polyol component, a foaming agent, a catalyst, a foam stabilizer and other auxiliaries, a foaming agent is used. As a combination of a liquid HFC at normal temperature and normal pressure and a gas HFC at normal temperature and normal pressure,
A part or all of the liquid HFC at room temperature and normal pressure is previously mixed with the compounded liquid, and when the temperature is raised in a closed container, the internal pressure at a liquid temperature of 60 ° C. becomes 1.5 kg / g.
cm ² or less (hereinafter, this pressure is referred to as “60 ° C. internal pressure”), and a gaseous HFC at normal temperature and normal pressure or a gaseous HFC at normal temperature and normal pressure and a liquid at normal temperature and normal pressure are prepared. The rest of the HFC is introduced when reacting this blended liquid with the polyisocyanate component.

The internal pressure of 60 ° C. refers to a condition in which the liquid mixture is filled in a closed container at normal temperature and normal pressure and the temperature is raised.
This is the internal pressure when the liquid temperature reaches 60 ° C.

In the present invention, HFC which is liquid at normal temperature and pressure is used.
Although there is no particular limitation, 1,1,1,3,3-pentafluoropropane, 1,1,1,2,3,3-hexafluoropropane, 1,1,1,3,3,3 -Hexafluorobutane or the like can be used. There is no particular limitation on the gaseous HFC at normal temperature and normal pressure.
1,2-tetrafluoroethane, 1,1,1,3,3-
Pentafluoroethane, 1,1-difluoroethane and the like can be used.

If the amount of gaseous HFC used at room temperature and pressure is too small, the improvement effect of the present invention cannot be sufficiently obtained by using it together, but the amount of gaseous HFC used at room temperature and pressure is excessive. If the amount is too large, the foaming power is too strong, voids are formed inside the foam, and the spray pattern is disturbed. Therefore, the amount of gaseous HFC used at room temperature and normal pressure is the use of other blowing agents including liquid HFC at room temperature and normal pressure. In general, the total weight of the polyisocyanate component, the blended liquid excluding the liquid HFC at normal temperature and normal pressure, and the liquid HFC at normal temperature and normal pressure, that is, the amount differs depending on the required core density of the foam, that is, , With respect to the total weight of the raw materials other than gaseous HFC at normal temperature and normal pressure.
It is preferably 5 to 10% by weight, particularly preferably 0.5 to 5% by weight.

In the present invention, it is preferable to use a liquid HFC at normal temperature and normal pressure and a gaseous HFC at normal temperature and normal pressure as the foaming agent, and to mix and use water in advance in the liquid mixture.

The amount of HFC that is liquid at normal temperature and normal pressure varies depending on whether water is used and the core density of the intended foam. However, in general, the total amount of raw materials other than gaseous HFC at normal temperature and normal pressure is used. By using about 1.5 to 10% by weight of liquid HFC and about 0.5 to 3% by weight of water at normal temperature and normal pressure, a rigid polyurethane foam having a core density of 20 to 40 kg / m ³ is formed. Is preferred. When the core density is less than 20 kg / m ³ , the foam strength is insufficient,
If it exceeds 40 kg / m ³ , a problem due to high density occurs.

The ratio of the HFC which is liquid at normal temperature and normal pressure, which is previously mixed with the compounded liquid, is the above-mentioned 60 ° C. and 1.5 k internal pressure.
g / m ² or less may be used, and there is no particular limitation. Generally, at least 50% by weight of liquid HFC at room temperature and normal pressure to be used, preferably, the whole amount is previously Mix with the blended liquid, 60 ° C internal pressure 0.2-1.4k
It is preferable to prepare a compounded liquid having a viscosity of 500 cps or less, particularly 80 to 300 cps at a liquid temperature of 20 ° C. at g / cm ² .

Hereinafter, the raw materials other than the foaming agent used in the present invention will be described.

(1) Polyisocyanate Component Polyisocyanate components include aromatic polyisocyanate compounds such as diphenylmethane diisocyanate and tolylene diisocyanate, alicyclic polyisocyanates such as isophorone diisocyanate, and aliphatic polyisocyanates such as hexamethylene diisocyanate. One or more kinds of polyisocyanates can be used. In addition,
The isocyanate index of the polyisocyanate component is 100
It is preferably from 200 to 200.

(2) Polyol Component The polyol component includes polyether polyols obtained by ring-opening addition polymerization of alkylene oxides such as ethylene oxide and propylene oxide to glycerin, pentaerythritol, sucrose, ethylenediamine and the like, and adipic acid Use of one or more of polyester polyols and the like obtained by polycondensation reaction of polybasic acid such as succinic acid and polyhydroxyl compound such as ethylene glycol and propylene glycol, or ring-opening polymerization of lactones Can be. The hydroxyl value of the polyol component is 250
Preferably, it is で 400 mg-KOH / g.

(3) Catalyst Examples of the catalyst include amine catalysts such as triethylenediamine, pentamethyldiethylenetriamine and tetramethylhexamethylenediamine, dibutyltin dilaurate, lead octylate, stannas octoate, potassium octylate (2-ethylhexylate). One or more kinds of organometallic catalysts such as potassium) and potassium acetate can be used.

(4) Foam stabilizers Any foam stabilizers that are effective for producing rigid polyurethane foams can be used. For example, polyoxyalkylene-based ones such as polyoxyalkylene alkyl ethers and silicone-based ones such as organopolysiloxane can be used.

Further, in the present invention, optional components other than those described above, for example, a flame retardant, a plasticizer, a filler and the like can be used as long as the object of the present invention is not hindered.

In the case of airless spray foaming, for example, the rigid polyurethane foam of the present invention comprises at least a part of HFC which is liquid at room temperature and pressure as a foaming agent, optionally water, a catalyst, a foam stabilizer and other components. A mixture of a polyol component with an auxiliary agent, a polyisocyanate component, a gaseous HFC at room temperature and normal pressure as a combined foaming agent, and optionally a balance of liquid HFC at room temperature and normal pressure, at 30 to 50 ° C. It can be manufactured by mixing using a mixing head, spraying the mixture at a discharge pressure of 40 to 80 kg / cm ² on the surface to be processed, and repeatedly spraying the mixture until a predetermined thickness is achieved.

In this case, gaseous HFC at normal temperature and normal pressure, gaseous HFC at normal temperature and normal pressure, and liquid HFC at normal temperature and normal pressure
Is preferably introduced directly into the mixing head or into a conduit for other components leading to the mixing head and mixed therewith.

The rigid polyurethane foam of the present invention can be applied not only to airless spray foaming but also to rigid polyurethane foam by injection molding or continuous foam molding. In particular, airless spray foaming requires high workability. Therefore, in accordance with the present invention, an excellent effect can be obtained by improving foam formability and workability by using a combination of liquid HFC at normal temperature and normal pressure and gaseous HFC at normal temperature and normal pressure.

[0036]

The present invention will be described more specifically below with reference to examples and comparative examples.

Examples 1 and 2 and Comparative Examples 1 to 4 According to the formulation shown in Table 1, formulation A was prepared and polyisocyanate was prepared. In Comparative Example 4, a stock solution A was made of Bridgestone Corporation's flame retardant grade 3 dew condensation preventing stock solution "RG-5249" (using HCFC141b as a foaming agent). The raw materials used for the polyisocyanate and the mixture A are as follows. The physical properties of the prepared mixture A were evaluated by the following methods, and the results were shown in Table 1.
It was shown to.

[Evaluation of Physical Properties of Compounded Liquid A] Viscosity: The viscosity at a liquid temperature of 20 ° C. was measured with a B-type viscometer. 60 ° C. internal pressure: 200 ml of liquid mixture A at a liquid temperature of 20 ° C.
The liquid was filled in a cc closed container and heated, and the gauge pressure when the liquid temperature reached 60 ° C. was measured. Volume increase rate during stirring: 2 in a beaker with a volume of 1000 cc
Pour 00cc of Compound A (liquid temperature 35 ° C) and
The volume increase rate when stirring at pm for 5 seconds was measured.

[Raw Materials] Polyisocyanate: "C-1156" manufactured by Nippon Polyurethane Industry Co., Ltd. Crude diphenylmethane diisocyanate (NCO%: 30.2) Polyol A: Tolylenediamine / Sucrose-based polyether manufactured by Asahi Glass Co., Ltd. Polyol Hydroxyl value: 440 mg-KOH / g Polyol B: Ethylenediamine-based polyether polyol manufactured by Takeda Pharmaceutical Co., Ltd. Hydroxyl value: 750 mg-KOH / g Polyol C: Aminoethylpiperazine / monoethanolamine-based polyol manufactured by Asahi Glass Co., Ltd. Reether polyol Hydroxyl value: 312 mg-KOH / g Flame retardant A: Tributyl phosphate manufactured by Akzo Nobel Flame retardant B: "TCPP" (Tris monochloropropyl phosphate) manufactured by Daihachi Chemical Co., Ltd. Foam stabilizer : "L5420" (a block copolymer of dimethylsiloxane and polyether) manufactured by Nippon Unicar Co., Ltd. Catalyst A: 33% by weight solution of triethylenediamine manufactured by Kao Corporation Catalyst B: Tetramethylhexamethylenediamine manufactured by Kao Corporation Catalyst C: Pentamethyldiethylenetriamine manufactured by Kao Corp. Catalyst D: Dioctyl phthalate solution of lead octylate (17% by weight) manufactured by Nippon Chemical Industry Co., Ltd. Blowing agent A: Water Blowing agent B: Asahi Glass Co., Ltd. 1,1 , 1,3,3-Pentafluoropropane foaming agent C: 1,1,1,2-tetrafluoroethane manufactured by Mitsui DuPont Fluorochemicals Co., Ltd. And the amount of polyisocyanate shown in Table 1 and the amount of polyisocyanate shown in Table 1 Pumped amount of the foaming agent C from the main pump (although without a blowing agent C in Comparative Examples 1 to 4), to form a rigid polyurethane foam by blowing the skeleton (calcium silicate board). The construction environment temperature is 15 ~ 20 ℃
The body temperature is set equal to the ambient temperature, the discharge liquid temperature in the foaming machine is 35 ° C, and the air pressure of the air pump is 5 kg
/ Cm ² .

The core density, the presence or absence of delamination, the thermal conductivity and the spray pattern of the obtained rigid polyurethane foam were examined by the following methods. The results are shown in Table 1.

The core density was measured according to JIS A9526 from a foam sprayed to a total thickness of 80 to 100 mm (laminated four times). Interlayer delamination The presence or absence of delamination in the cross section between the laminations of the four-layered foam was observed. Thermal conductivity Measured according to JIS A1412. The spray pattern was discharged from a position 1 m from the surface of the main body, and the diameter of the obtained foam-adhered portion was measured.

[0042]

[Table 1]

Table 1 shows that according to the present invention, a rigid polyurethane foam having good characteristics can be obtained.

[0044]

As described above in detail, according to the rigid polyurethane foam of the present invention, a hydrofluorocarbon having no problem of destruction of the ozone layer is used as a foaming agent, so that the foam is excellent in formability and, therefore, the foam having heat insulation and the like. It is possible to provide a high-performance rigid polyurethane foam having excellent properties and excellent workability.

Continued on the front page (72) Inventor Masashi Ishii 1 Kashio-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture F-term in Bridgestone Yokohama Plant 4F074 AA78 BA53 BA95 BB01 BB08 BB29 BC01 CA21 CA23 CC32Y CC34Y DA02 DA15 DA32 4J002 CH022 CK031 CK041 CP032 EB066 FD202 FD326 GL00 GQ00 4J034 BA03 DA01 DB03 DF11 DF16 DF20 DG02 DG03 DG04 DG14 HA01 HA07 HC03 HC12 HC17 HC22 HC52 HC64 HC67 HC71 HC73 KB02 KD12 NA02 NA05 QB16 QC01 RA15

Claims (8)

[Claims] 1. A rigid polyurethane foam obtained by reacting a polyisocyanate component with a compounded liquid obtained by mixing a polyol component, a foaming agent, a catalyst, a foam stabilizer and other auxiliaries, wherein the foaming agent is at room temperature and normal pressure. A rigid polyurethane foam, wherein a liquid hydrofluorocarbon and a gaseous hydrofluorocarbon at normal temperature and normal pressure are used, and at least a part of the liquid hydrofluorocarbon at normal temperature and normal pressure is previously mixed with the mixed liquid, A rigid polyurethane foam, wherein the internal pressure at a liquid temperature of 60 ° C. is 1.5 kg / cm ² or less when the liquid is heated in a closed container. 2. The liquid hydrofluorocarbon according to claim 1, wherein the mixed liquid excluding the polyisocyanate component, the liquid hydrofluorocarbon liquid at normal temperature and normal pressure, and the liquid hydrofluorocarbon liquid at normal temperature and normal pressure are used. A rigid polyurethane foam used in the range of 0.5 to 10% by weight based on the total weight. 3. The method according to claim 1, wherein the hydrofluorocarbon liquid at normal temperature and normal pressure is 1,1,1,3,3.
A rigid polyurethane foam, which is 3-pentafluoropropane. 4. The rigid polyurethane foam according to claim 1, wherein the gaseous hydrofluorocarbon at normal temperature and normal pressure is 1,1,1,2-tetrafluoroethane. 5. The composition according to claim 1, wherein the viscosity of the liquid mixture is 500 cp at a liquid temperature of 20 ° C.
s or less. 6. The rigid polyurethane foam according to claim 1, wherein the core density is 20 to 40 kg / m ³ . 7. The rigid polyurethane foam according to claim 1, wherein the rigid polyurethane foam is obtained by airless spray foaming in which the polyisocyanate component and the compounding liquid are mixed and foamed by a mixing head. 8. The mixing head according to claim 7, wherein the gaseous hydrofluorocarbon at normal temperature and normal pressure, or the remaining hydrofluorocarbon at normal temperature and normal pressure and the remaining hydrofluorocarbon at normal temperature and normal pressure are mixed in a mixing head or in a mixing head. A rigid polyurethane foam characterized by being directly introduced into and mixed with a conduit for other components leading to a head.