JPH09328530A - Production of flame-retardant rigid polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flame-retardant rigid polyurethane foam excellent in flame retardance and dimensional stability by using a combination of specific compds. as the polyol component in producing an isocyanurate-modified polyurethane foam. SOLUTION: A combination of a phthalate-base polyester polyol with a propylene oxide and/or ethylene oxide adduct of bisphenol A pref. in a wt. ratio of (50:50)-(90:10) is used as the polyol component in producing an isocyanurate-modified polyurethane foam by reacting an isocyanate compd. (e.g. crude MDI) with a polyol component in the presence of a catalyst and a foam stabilizer (e.g. a silicone surfactant) while using HCFC-141b as the blowing agent. Pref. the catalyst is a trimerization catalyst prepd. by mixing 100-40wt.% potassium octanoate with 0-60wt.% potassium acetate or is a mixture of the trimerization catalyst with dimethylcyclohexylamine in a wt. ratio of (100:0)-(40:60).

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 polyurethane foam, and more particularly to a method for producing an isocyanurate-modified polyurethane foam having high flame retardancy.

[0002]

2. Description of the Related Art Rigid polyurethane foam has been widely used as a heat insulating material, a structural material and the like. In particular, phthalic acid-based polyester polyol is mainly used as a polyol, and in order to further improve strength and moldability, sucrose-based, pentaerythritol-based, sorbitol-based, ethylenediamine-based, glycerin-based, trimethylolpropane-based polyol propylene, etc. Isocyanurate-modified polyurethane foam obtained by appropriately adding oxide and / or ethylene oxide adduct is suitable for building materials and the like due to its excellent flame retardancy, and in the production thereof, conventionally,
CFC-11 (trichloromonofluoromethane) has been used as a foaming agent, carboxylic acid metal salt, quaternary ammonium salt, amine, etc. as a trimerization catalyst, silicon surfactant as a foam stabilizer, and crude MDI as an isocyanate. It was

However, in order to prevent ozone layer depletion, the use and removal of specific CFCs was decided, and the above-mentioned blowing agent, C, was used.
FC-11 could not be used either. CFC-11
As an alternative to HCFC-141b (1,1-
Dichloro-1-fluoroethane) has attracted attention and has already been put into practical use.

However, when HCFC-141b is used instead of CFC-11 in the conventional formulation as described above, the flame retardancy (low smoke generation) and dimensional stability (cold shrinkage resistance) of the polyurethane foam are deteriorated. There was found.

That is, while the conventional CFC-11 was nonflammable, HCFC-141b was flammable, so that when it was used as a foaming agent, the amount of smoke emitted increased (CA
(Value> 60), the problem of not reaching the level of flame retardancy class 2 occurred. Further, since HCFC-141b is melted into the foam and the strength of the foam itself is lowered, there is a problem that cold shrinkage resistance occurs.

The present invention has been made to solve the above-mentioned problems, and HCFC-141b is used as a foaming agent.
The present invention intends to provide a production method capable of obtaining a rigid polyurethane foam having excellent flame retardancy and improved dimensional stability even when used.

[0007]

In order to solve the above-mentioned problems, in the method for producing a flame-retardant rigid polyurethane foam according to claim 1, an isocyanate compound is added to a polyol in the presence of a catalyst and a foam stabilizer. In the method for producing a polyurethane foam, which is reacted to produce an isocyanurate-modified polyurethane foam using HCFC-141b as a blowing agent, a phthalate polyester polyol and propylene oxide and / or ethylene oxide adduct of bisphenol A are used as the polyols. And are used together.

In the production method of claim 2, the weight ratio of the phthalic acid type polyester polyol to the propylene oxide and / or ethylene oxide adduct of bisphenol A is 50:50 to 90: in the method of claim 1.
It is assumed to be 10.

According to the manufacturing method of claim 3, claim 1 or 2
In the above method, the catalyst is a trimerization catalyst in which potassium octylate and potassium acetate are mixed in a weight ratio of 100: 0 to 40:60, or the trimerization catalyst and dimethylcyclohexylamine are 100: 0 to 40. : 60 weight ratio is used.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, it is premised that HCFC-141b is used as a foaming agent.
In order to solve the problems of deterioration of dimensional stability and flame retardancy when using CFC-141b, phthalic acid polyester polyols as polyols and propylene oxide (PO) and / or ethylene oxide (EO) of bisphenol A are used. Used in combination with an adduct (hereinafter referred to as bisphenol polyol).

The above-mentioned phthalic acid type polyester polyol is, for example, a polymer of ortho-form and / or para-form phthalic acid and polyhydric alcohols such as ethylene glycol and diethylene glycol.

The amount of PO and / or EO added to bisphenol A is 2 to 1 per 1 mol of bisphenol A.
0 mol is preferable and 3 to 8 mol is particularly preferable. Two
When it is less than mol, bisphenol A is solidified and it becomes difficult to use, and when it exceeds 10 mol, a sufficient improvement effect of dimensional stability cannot be obtained.

The blending ratio of the phthalic acid type polyester polyol and the bisphenol type polyol is preferably 50:50 to 90:10 by weight ratio (hereinafter the same), and 6
0:40 to 80:20 is particularly preferable. If the proportion of the phthalic acid-based polyester polyol is too low, the flame retardancy of the resulting product will be insufficient, and if the proportion of the bisphenol-based polyol is too low, the dimensional stability will be insufficient.

OH of phthalic acid type polyester polyol
The value is preferably 100 to 500, and particularly preferably 150 to 400. When the OH value is less than 100, the dimensional stability becomes insufficient, and when it exceeds 500, the flame retardancy becomes insufficient.

As the catalyst, a trimerized mixed catalyst composed of potassium octylate and potassium acetate can be preferably used. The compounding ratio of both is preferably 100: 0 to 40:60, more preferably 90:10 to 60:40. If the proportion of potassium octylate is too low, the flame retardancy becomes insufficient. Further, a mixture of the trimerization mixed catalyst and dimethylcyclohexylamine in a ratio of 100: 0 to 40:60 is particularly preferable for improving flame retardancy.

As the foam stabilizer, a silicon-based surfactant conventionally used in the production of polyurethane foam is appropriately used.

As the isocyanate compound, those conventionally used in the production of polyurethane can be used. That is, it is a simple substance or a mixture of alicyclic, aliphatic and aromatic polyisocyanates, but crude MDI (polymeric MDI) is particularly preferable. 200-600 are preferable and, as for the NCO index of an isocyanate compound, 250-450 are especially preferable.

In the above, the amount of the isocyanate compound used is determined by the OH value of the polyol and the NCO index. Further, the amounts of the catalyst and the foaming agent used are not particularly limited, and are determined so that the desired reactivity and foaming density can be obtained. Specifically, it can be determined from the density (free density) of the core portion of the foam obtained by performing free foaming of the raw material mixture.

In the production method of the present invention, additives usually used in the production of polyurethane foam, such as phosphorus-based flame retardants and viscosity reducers, can be appropriately used.

In the present invention, the method of mixing and foaming the raw materials is not particularly limited, and any method may be used as long as the reaction mixture is uniformly mixed. For example, injection foaming, continuous foaming, spray foaming and the like which have been conventionally used for producing polyurethane foam and the like can be used.

[0021]

EXAMPLES Next, the production method of the present invention will be described more specifically by showing examples, but the present invention is not limited to these examples.

Examples 1 to 8 Table 1 shows a foam stabilizer, water, a catalyst (potassium octylate, potassium acetate and dimethylcyclohexylamine) per 100 parts by weight of polyols (phthalic acid type polyester polyol, bisphenol type polyol). And the blowing agent and crude MDI were mixed in the proportions (parts by weight) shown in Table 1 and mixed. Potassium octylate (Perlon 9540) is 15 wt% ethylene glycol solution, potassium acetate (LK-25) is 25 wt%
It was used as a diethylene glycol solution, but the weight ratios and blending ratios shown in the table are in terms of solid content.

Specimens were prepared according to the following methods, and their dimensional stability (cold shrinkage resistance) and flame retardancy (low smoke generation) were examined. The results are shown in Table 1. In the following Examples and Comparative Examples, the gelation time was adjusted to 60 ± 10 seconds and the free density was adjusted to 25 ± 1 kg / m ³ by adjusting the amounts of the catalyst and the blowing agent.

Dimensional stability 200 vertical x 200 horizontal x 100 thickness (each mm, same below)
Freely foam with the box-shaped open mold, and the core of the resulting foam is 100 length × 100 width × 100 thickness.
It was cut into a size of and used as a test body.

This test body was placed in an atmosphere of -30 ° C. × 48 hrs and the shrinkage ratio was measured.

Flame retardance A mold having a length of 300 × width of 300 × thickness of 50 (each mm, the same applies hereinafter) is heated to a mold temperature of 60 ° C., and an injection density is 42 kg / m.
^{It was} adjusted to ³ and injected, and the mold was removed in 20 minutes. The core portion of the obtained release foam was cut into a size of length 220 × width 220 × thickness 20 and used as a test body.

Regarding this test piece, JIS A-1321
The CA value was measured by the flame-retardant second-class test method.

Comparative Examples 1 to 10 Sucrose-based polyols, sorbitol-based polyols, ethylenediamine-based polyols and tolylenediamine-based polyols were used as the polyols other than those used in the examples, and Table 2 shows the blending ratio of each component. Specimens were prepared in the same manner as in the above-described examples except that the above was performed, and the dimensional stability and flame retardancy were examined. The results are also shown in Tables 2 and 3 (continuation of Table 2).

[0029]

[Table 1] .

[0030]

[Table 2] .

[0031]

[Table 3]

[0032]

According to the manufacturing method of claim 1 of the present application, by using the phthalic acid type polyester polyol and the propylene oxide and / or ethylene oxide adduct of bisphenol A in combination, HCFC-1 as a foaming agent is obtained.
Even when 41b is used, it is possible to obtain a flame-retardant rigid polyurethane foam which is excellent in dimensional stability, has a small amount of smoke, and can be suitably used for building material applications and the like.

Particularly, according to the second aspect of the present invention, the dimensional stability and the flame retardance are balanced by specifying the mixing ratio of the phthalic acid type polyester polyol and the propylene oxide and / or ethylene oxide adduct of bisphenol A. A rigid flame-retardant rigid polyurethane foam is obtained.

Further, according to the third aspect, the flame retardancy is further improved.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI technical display location C08G 101: 00) (72) Inventor Kiyo Shiro 1-17-18 Edobori, Nishi-ku, Osaka-shi, Osaka No. Toyo Tire & Rubber Co., Ltd. (72) Inventor Akihiro Fujio 1-17-18 Edobori, Nishi-ku, Osaka City, Osaka Prefecture Toyo Tire & Rubber Co., Ltd.

Claims (3)

[Claims] 1. An isocyanate compound is reacted with a polyol in the presence of a catalyst and a foam stabilizer to form HC as a foaming agent.
In the method for producing a polyurethane foam for producing an isocyanurate-modified polyurethane foam using FC-141b, it is preferable to use a phthalic acid-based polyester polyol and a propylene oxide and / or ethylene oxide adduct of bisphenol A in combination as the polyols. A method for producing a flame-retardant rigid polyurethane foam, which is characterized. 2. The weight ratio of the phthalic acid-based polyester polyol to the propylene oxide and / or ethylene oxide adduct of bisphenol A is 50: 50-9.
The method for producing a flame-retardant rigid polyurethane foam according to claim 1, wherein the ratio is 0:10. 3. As the catalyst, a trimerization catalyst in which potassium octylate and potassium acetate are mixed in a weight ratio of 100: 0 to 40:60, or this trimerization catalyst and dimethylcyclohexylamine are from 100: 0. 2. Use of a mixture in a weight ratio of 40:60.
Or the method for producing a flame-retardant rigid polyurethane foam according to item 2.