JPH0782406A - Production of rigid polyurethane foam - Google Patents

Abstract

PURPOSE:To produce a rigid polyurethane foam containing fine cells and having excellent filling property, heat-insulation property and low-temperature dimensional stability without causing the ozonosphere destruction by mixing an organic polyisocyanate, a polyol, a specific foaming agent, a catalyst, a surfactant and an assistant. CONSTITUTION:This rigid polyurethane foam containing uniformly distributed fine cells and having excellent physical properties such as heat-insulation property and low-temperature dimensional stability can be produced using a foaming agent free from the ozonosphere destruction problem by compounding an organic polyisocyanate (e.g. diphenylmethane diisocyanate), a polyol (e.g. tolylenediamine- propylene oxide adduct of polyether polyol), 1,3-dioxolan as a foaming agent, a catalyst (e.g. dibutyltin dilaurate), a surfactant and other assistants such as flame-retardant, plasticizer, filler, stabilizer and colorant, quickly stirring and mixing the components and immediately filling in an aluminum box to effect the free expansion of the mixture.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a rigid polyurethane foam.
Relates to a method for manufacturing a glass. More specifically, by using 1,3-dioxolane as a foaming agent, foam filling properties,
The present invention relates to a method for producing a rigid polyurethane foam having excellent low-temperature dimensional stability, compressive strength, and heat insulation properties, and having extremely uniform and fine cells.

[0002]

2. Description of the Related Art Rigid polyurethane foams have heat insulating properties,
Because of its excellent low-temperature dimensional stability, it is widely used as a heat insulating material for refrigerators, frozen warehouses, etc. This is because trichlorofluoromethane (commonly called CFC), which has excellent heat insulating properties, is used as a foaming agent when manufacturing a rigid polyurethane foam.
-11), dichlorodifluoromethane (commonly known as CFC-1
The main reason is that 2) is used.

However, in recent years, regulation of chlorofluorocarbons has been implemented to protect the earth's ozone layer. Until now, the subject of this regulation is rigid polyurethane foam.
CFC-11, CF used as a foaming agent
C-12 is also included. Therefore, CFC-11, 12
There is an urgent need to develop a foaming agent for rigid polyurethane foam, which replaces the above.

[0004]

Currently, CFC-11,
As a halogen-free foaming agent replacing CFC-12, for example, an aliphatic hydrocarbon compound having 2 to 7 carbon atoms has been proposed and partially put into practical use. However, since these compounds have poor compatibility with existing polyols, the polyols and the foaming agent are easily separated from each other. Therefore, in the case of producing a polyurethane foam, the purpose is to maintain a uniform dispersion. It is necessary to devise such as installing additional equipment. Further, the conventional method of previously mixing a polyol, a foaming agent, a foam stabilizer, a catalyst and other auxiliaries and supplying them as a system cannot be performed. Further, for example, cyclopentane has a flash point of -42 ° C and an explosion limit of 1.4% as a lower limit, so strict safety measures must be taken for the foam manufacturing equipment and the building. Therefore, there is a problem that the manufacturing cost is increased for producers such as refrigerators.

On the other hand, since the obtained foam has poor compatibility with polyols, it is difficult to obtain uniform and fine cells. Compared with the case where CFC-11 and 12 are used as a foaming agent. However, there is a drawback in that the heat insulation performance is significantly reduced. Although this is useful for protecting the ozone layer, it goes against the goal of resource saving and energy saving, leads to consumption of a large amount of fossil energy, and leads to the promotion of global warming. Although a so-called water-foaming method in which only carbon dioxide gas generated by the reaction of water and isocyanate is used as a foaming agent has been partially put into practical use, the resulting rigid polyurethane foam is remarkably inferior in heat insulation. In addition, since the strength is low and the practical density is high, when used as a heat insulating material, it is necessary to make the thickness thicker or the density higher than that of the conventional foam, so that the usage amount increases. There is.

[0006]

The present inventors have made diligent efforts to overcome the above-mentioned problems, and as a result, have low toxicity as a foaming agent for rigid polyurethane foam instead of CFC-11 conventionally used. Highly safe, 1,3-doxolane shows excellent foam filling property, and also has excellent low temperature dimensional stability, compressive strength and heat insulation, and has uniform and fine cells. The inventors have found that a rigid polyurethane foam is produced and have reached the present invention.

Since 1,3-dioxolane has excellent compatibility with polyols, it can be pre-mixed as in the case of CFC-11, so that conventional equipment can be used as it is. . Further, it is possible to supply a system in which a polyol, a foaming agent, a foam stabilizer, a catalyst and other auxiliary agents are premixed. Furthermore, 1,3-dioxolane has a flash point of 2 ° C and an explosion limit lower limit of 4.5%. For example, the flash point is 40 ° C when compared to cyclopentane.
The above is also high, the lower limit explosion limit concentration is about three times, the equipment for ensuring safety is simple, and it is easy to handle. Therefore, manufacturers such as refrigerators can rationalize the manufacturing cost. , Which is remarkably preferable. Furthermore,
Since 1,3-dioxolane has excellent solubility with polyethers, the shape of the cells of the foam can be made uniform and fine, and therefore, it is almost the same as that of the conventional CFC-11 or 12 blowing agent. The heat insulation property of is obtained.

The present invention is a method for producing a rigid polyurethane foam from an organic polyisocyanate, a polyol, a foaming agent, a catalyst, a surfactant and other auxiliaries, and 1,3-dioxolane as a foaming agent. And a method for producing a rigid polyurethane foam. The organic isocyanate used in the present invention is conventionally known and is not particularly limited, and aromatic, aliphatic, alicyclic polyisocyanate and modified products thereof such as diphenylmethane diisocyanate and crude Diphenylmethane diisocyanate, tolylene diisocyanate, crude tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, triphenylmethylene triisocyanate, tri Lentriisocyanate, etc., and a mixture thereof, and an isocyanate obtained by reacting an excess amount of these polyisocyanates with polyol (for example, low molecular weight polyol / or polymer polyol). Examples thereof include a prepolymer having a terminal group.

These isocyanates may be used alone or in admixture of two or more. The amount used is not particularly limited, but it is suitable that the equivalent ratio of the NCO group to the active hydrogen in the polyol described below is about 0.8 to 3.5. The polyol used in the present invention is, for example, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, 1,3,6-hexane. Triol, pentaerythritol, sorbitol, sucrose, bisphenol A, novolac, hydroxylated 1,2-polybutadiene, hydroxylated 1,4-
Polyhydric alcohols such as polybutadiene, and / or hydroxyl value of 150 to 1000 mg KOH obtained by addition-polymerizing alkylene oxide to these polyhydroxy compounds
/ G of polyether polyol can be used.

Further, diethanolamine and triethanolamine
Alkanolamines such as ruamine, aliphatic amines such as ethylenediamine and diethylenetriamine, 2,
4- and / or 2,6-diaminotoluene, 2,4'-
And / or 4,4′-diaminodiphenylmethane, 1,
5-naphthalenediamine, 2,4-diamino-3,6-
Diethyltoluene, 2,4-diamino-5,6-diethyltoluene, 2,6-diamino-3,5-diethyltoluene, 2,6-dianimo-3,4-diethyltoluene,
Polyethylene having a hydroxyl value of 150 to 1000 mgKOH / g obtained by adding alkylene oxide to aromatic amines such as 2,6-diamino-4,5-diethyltoluene or a mixture of these isomers diaminodiethyltoluene.
Terpolyol can be used.

In addition to the above, polyester polyols obtained by reacting higher fatty acid ester polyols and polycarboxylic acids with low molecular weight polyols and polyester polyols obtained by polymerizing caprolactone can also be used. The polyol which can be used in the present invention is one of the above-mentioned polyols.
It can be used as a kind or a mixture of two or more kinds.

The catalyst which can be used in the present invention is a conventionally known catalyst and is not particularly limited. For example, N-methylmorpholine, N-ethylmorpholine, N, N, N ', N'-tetramethylethylenediamine, tri- Ethylenediamine,
Further, various amine compounds such as N, N ', N "-trialkylaminoalkylhexahydrotriazines, organometallic compounds such as tin oleate, dibutyltin diacetate and dibutyltin dilaurate are used. These catalysts may be used alone or in a mixture, and the amount thereof used is 0.1 to 10.0 with respect to 100 parts by weight of the compound having active hydrogen.
Weight parts are appropriate.

The foam stabilizer in the present invention is a conventionally known organosilicon compound, for example, SH-193, SRX-295, SF- manufactured by Toray Dow Corning Silicone.
2931, SF-2932, SF-2933, etc., and L-5410, L-5420, manufactured by Nippon Unicar Co., Ltd.
L-5430, L-5340, etc., manufactured by Shin-Etsu Silicon Co., Ltd. F-341, F-345, F-305, F-.
350S, etc. The amount of these foam stabilizers to be used is not particularly limited, but 0.1 to 10 parts by weight is suitable for 100 parts by weight of the total of the compound having active hydrogen and the organic polyisocyanate. Further, as the flame retardant, for example, tris (2-chloroethyl) phosphate, tris (dichloropropyl) phosphate, tris (dibromopropyl) phosphate, and Fyrol 6 manufactured by Stoffer can be used. In addition, a plasticizer, a filler, a stabilizer, a coloring agent and the like can be added if necessary.

To carry out the present invention, a predetermined amount of a polyol, a catalyst, 1,3-dioxolane as a foaming agent, a foam stabilizer, and optionally a flame retardant and other auxiliaries are mixed. To make resin solution. Using an existing low-pressure and high-pressure foaming machine, a resin solution and an organic polyisocyanate are continuously rapidly stirred at a predetermined ratio and injected into a void or a mold of an object to manufacture a urethane foam. At this time, the equivalent ratio of the active hydrogen-containing compound and the organic polyisocyanate is 0.8 to
The volume ratio of the resin solution and the polyisocyanate is adjusted so that it becomes 3.5. Urethane foam produced by the present invention
The aluminum can be used as a heat insulating material or a structural material for electric refrigerators, heat insulating panels, ships, vending machines, cases, vehicles and the like.

[0015]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the Examples. The raw materials used in the present invention are as follows. Millionate MR-200: Polymeric Isocyanate Polyol A manufactured by Nippon Polyurethane Co., Ltd .: Polyethylene polyol having a hydroxyl value of 390 mgKOH / g obtained by adding propylene oxide to tolylenediamine Polyol B: Triethanol -Polyenepolyol with hydroxyl value of 400 mg KOH / g obtained by adding propylene oxide to amine-polyol C: Polyetherpolyol with hydroxyl value of 490 mgKOH / g obtained by adding propylene oxide to glycerin Catalyst: manufactured by Kao Corporation Kao-Riser-No. 1
(TMHD) Foam stabilizer: SH-193 1,3 dioxolane manufactured by Toray Industries, Inc .: manufactured by Toho Chemical Industry Co., Ltd. Cyclopentane: manufactured by Tokyo Chemical Industry Co., Ltd.

[0016]

EXAMPLES AND COMPARATIVE EXAMPLES Resin solutions having the formulations shown in Table 1 were prepared, and Millione Neat MR-200 was added thereto to prepare a resin solution.
2,000 rpm with rapid stirring and mixing for 5 seconds, size 200 ×
It was immediately transferred into a 200 × 200 mm aluminum box and allowed to freely foam. A foam sample for measuring physical properties such as dimensional change rate and compressive strength has a size of 500 × 500 × 50 mm.
The aluminum jig was applied and foamed to adjust the finished density to 32 and 35 kg / m ³ .

[0017]

[Table 1]

Note C-MDI: Millionate MR-200 ρ: Density Kg / m ³ PO / A: Polyol A C.I. S: Compressive strength Kg / m ² PO / B: Polyol B D. S: Low temperature dimensional stability PO / C: Polyol B -30 ° C, 48Hrs 1,3DO: 1,3dioxolane Kf: Thermal conductivity CP: Cyclopentane Kcal / m, hr, ° C CT: Cream time GT: Gel time FT: Form time

[0019]

As is apparent from the above description, the present invention has the following advantages.
The following effects were obtained. That is, Polio,
Excellent compatibility with catalysts, foam stabilizers and other auxiliaries
By using 3 dioxolane as a foaming agent,
Foam filling from a wide range of raw materials, low temperature dimensional stability,
It has become possible to manufacture a hard urethane foam having excellent compressive strength and heat insulation and having a uniform and fine cell structure. Furthermore, compared with hydrocarbons such as cyclopentane, it has become possible to further enhance safety in production management such as resinization, storage, transportation, and foaming. In particular, since no CFC or HCFC that causes ozone layer depletion is used, it can be recommended as an extremely useful foaming means for protecting the global environment.

Claims (1)

[Claims] 1. A method for producing a rigid polyurethane foam from an organic polyisocyanate, a polyol, a foaming agent, a catalyst, a surfactant and other auxiliaries, wherein 1,3-dioxolane is used as a foaming agent. A method for producing a rigid polyurethane foam, comprising: