JPH1160671A - Hard polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hard polyurethane foam which is prepared by using an alternative blowing agent, and nevertheless has not only good flame retardancy but also excellent mechanical strength and dimensional stability. SOLUTION: This hard polyurethane foam is prepared by admixing a polyisocyanate component and a liquid compound obtained from a polyol component, a blowing agent, a catalyst, a foam-controlling agent and other auxiliaries, and then foaming the resulting admixture. The polyol component comprises one or more polybasic acid components selected from the group consisting of m-phthalic acid, p-phthalic acid, trimellitic acid and derivatives thereof and a hydroxyl-containing compound component, wherein the hydroxyl-containing compound component contains three or more functional hydroxyl-containing compounds in a proportion of 5 wt.% or more, and wherein the polyol component contains a polyester polyol compound obtained by esterification between a polybasic acid component and a hydroxyl-containing compound component in a proportion of 3 wt.% or more.

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 a method of mixing and foaming a polyisocyanate component and a compounded liquid obtained by mixing a polyol component, a foaming agent, a catalyst, a foam stabilizer and other auxiliaries. A rigid polyurethane foam having excellent flame retardancy, dimensional stability, and mechanical strength.

[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. Rigid polyurethane foams used in these applications are generally produced by mixing and foaming a polyisocyanate component and a compounded liquid obtained by mixing a polyol component, a foaming agent, a catalyst, a foam stabilizer and other auxiliaries.

[0003] As a general molding method, a slab stock is formed by mixing and stirring a stock solution (the above blended solution and a polyisocyanate component), and the slab stock is processed by cutting, bonding, or the like; There is a method of performing injection molding using a mold; or a method of performing foam molding by directly supplying an undiluted solution to a cavity to be molded or a construction surface (such as a frame) by an injection or spray method.

[0004]

In the case of rigid polyurethane foams, trichloromonofluoromethane, which has been conventionally used as a foaming agent, has a problem of destruction of the ozone layer. Ethane and the like have been proposed, and one of the problems is to improve the reduction in flame retardancy when these alternative foaming agents are used.

[0005] Polyether polyols and polyester polyols commonly used as polyhydroxy compounds for rigid polyurethane foams are listed.
Of these two types, the cohesive energy of CＯO in the polyester bond is high, so the polyester polyol is slightly
Polyester polyols are generally used in flame-retardant rigid urethane foams having high flame retardancy.

However, an aromatic polyester polyol as a polyol component generally used for flame-retardant rigid polyurethane foams is often a polyol obtained by esterifying a hydroxy compound having 2 functional groups. Rigid polyurethane foams obtained using such a bifunctional polyol component cannot be said to have sufficiently satisfactory mechanical strength and dimensional stability, and their improvement is desired.

The present invention has been made in view of the above-mentioned conventional circumstances, and is a hard polyurethane which has good flame retardancy and excellent mechanical strength and dimensional stability while using an alternative foaming agent. The purpose is to provide a form.

[0008]

The rigid polyurethane foam of the present invention is obtained by mixing and foaming a polyisocyanate component and a compounded liquid obtained by mixing a polyol component, a foaming agent, a catalyst, a foam stabilizer and other auxiliaries. In the obtained rigid polyurethane foam, the polyol component comprises one or more polybasic acid components selected from the group consisting of m-phthalic acid, p-phthalic acid, trimellitic acid and derivatives thereof, and a hydroxy compound component. Wherein the proportion of the tri- or higher functional hydroxy compound component in the hydroxy compound component is 5% by weight or more, and a polyester polyol compound obtained by subjecting the polybasic acid component and the hydroxy compound component to an esterification reaction Is contained in the polyol component in an amount of 3% by weight or more.

As described above, a polyester polyol obtained by subjecting a hydroxy compound component containing a tri- or higher functional hydroxy compound component to a polybasic acid component such as m, p-phthalic acid, trimellitic acid, etc., as a polyol component. By using the compound in a predetermined range, flame retardancy, dimensional stability, and mechanical strength can be increased.

In the following, a hydroxy compound having three or more functional groups is referred to as a “polyfunctional hydroxy compound”.

In the present invention, the content of the trifunctional or higher polyfunctional hydroxy compound in the hydroxy compound component is 10%.
Preferably, it is about 50% by weight. In the hydroxy compound component, the polyfunctional hydroxy compound component is 5% by weight.
It is preferable that the content of the above components and the polyester polyol obtained by esterifying the polybasic acids in the polyol component is 15% by weight or more.

[0012]

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

The polyol component used in the present invention comprises:
A compound containing 5% by weight or more of a trifunctional or higher polyfunctional hydroxy compound and one or more polybasic acids selected from the group consisting of m-phthalic acid, p-phthalic acid, trimellitic acid and derivatives thereof It contains 3% by weight or more of a polyester polyol compound obtained by subjecting components to an esterification reaction.

By using an ester of a polyfunctional hydroxy compound and a polybasic acid component containing an aromatic ring as described above, the flame retardancy, dimensional stability, and mechanical strength can be improved. That is, as a combustion system,
A cycle is considered in which the compound is thermally decomposed with the ignition to generate a flammable gas, thereby further expanding the burning portion and thermally decomposing the compound.

Considering this point, isophthalic acid, terephthalic acid, and trimellitic acid have a higher melting point and are less likely to be thermally decomposed than phthalic acid as a polybasic acid component. Can be

In the present invention, examples of the trifunctional or higher polyfunctional hydroxy compound include glycerin, trimethylolpropane, and trimethylolethane.

Among the polybasic acid components, derivatives of m, p-phthalic acid and trimellitic acid include diethyl m, p-phthalate and m, p-dimethyl phthalate.

The content of the polyester polyol compound according to the present invention is a ratio as a pure polyester polyol compound, and is a hydroxy compound or a polybasic acid contained in a product of an ester synthesis reaction in an unreacted state. Components and other additives are not included.

On the other hand, the polyhydroxy compound which can be used in combination with the polyester polyol is not particularly limited. For example, polyether polyols obtained by subjecting an alkylene oxide to ring-opening polymerization with glycerin, sucrose, ethylenediamine, etc. And the like, and each can be used alone or in combination of two or more kinds.If the reaction activity of the polyester polyol compound is low, a polyol such as a polyether polyol having a high reaction activity is used in combination to supplement the reaction activity. Things are desirable.

The polyester polyol compound as a reaction product obtained by the esterification reaction of such a polyhydrochloric acid component and a hydroxy compound component containing a polyfunctional hydroxy compound component has a hydroxyl value within the range of 200 to 500. , It is desirable to contain 3% by weight or more of all polyhydroxy compounds. If this ratio is less than 3% by weight, mechanical strength,
No significant effect is observed on dimensional stability. For the same reason, the ratio of the polyfunctional hydroxy compound in the hydroxy compound component is also set to 5% by weight or more.

On the other hand, as the polyisocyanate component,
Diphenylmethane diisocyanate is preferred, but other alicyclic isocyanates such as isophorone diisocyanate and aliphatic isocyanates such as hexamethylene diisocyanate may also be used.

Examples of the catalyst include amine catalysts such as triethylenediamine, tetramethylhexamethylenediamine, and pentamethyldiethylenetriamine, and amine compounds containing one or more hydroxyl groups in one molecule, specifically, dimethylaminohexanol and dimethylaminoethoxy. Reactive amine catalysts such as ethanol, trimethylaminoethylethanolamine, and other quaternary ammonium salts can be used.

Incidentally, dibutyltin dilaurate, lead octylate, stannas octoate, potassium octylate (2
Organometallic catalysts such as potassium ethylhexylate) and potassium acetate are indispensable components for urethane bond and promotion of isocyanurate modification, and they do not impair the flame retardancy by use. .

In the present invention, the amount of the catalyst used varies depending on the foaming conditions.
% By weight.

As the foaming agent, R-141b, R-22
HCFCs such as R-245fa, R-134a, R-
In addition to HFCs such as 236ea, HFEs such as R-347, etc., if necessary, one or more foaming agents of water, hydrocarbons such as cyclopentane, and hydrochlorocarbons such as methylene chloride. Can be used together.

The amount of the foaming agent is arbitrarily determined depending on the density of the target rigid polyurethane foam, but is usually 3 to 25% by weight, preferably 5 to 25% by weight based on the total of the polyol component and the polyisocyanate component. １５15% by weight.

As foam stabilizers, all those effective for producing rigid polyurethane foams can be used. For example, a silicone-based material such as polyoxyalkylene alkyl ether can be used in a usual amount. Further, in the present invention, optional components other than those described above, for example, a flame retardant, a filler and the like can be used as long as the object of the present invention is not hindered.

The rigid polyurethane foam of the present invention is prepared by mixing a blending component obtained by mixing a foaming agent, a catalyst, a foam stabilizer and other auxiliaries with a polyol component and a polyisocyanate component at 10 to 60 ° C. in a conventional manner. It can be easily manufactured by foaming, and its molding method is not limited, and any method such as casting and spraying can be applied.

It is preferable that the above components and the polyisocyanate component are mixed so that the isocyanate index becomes 150 to 350.

[0030]

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

Examples 1 to 3 and Comparative Examples 1 to 3 According to the formulation shown in Table 1, formulation A was prepared and polyisocyanate was prepared.

The raw materials used are as follows.

Polyol A: Mannich-modified polyol manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., hydroxyl value 470 Polyol B: p-phthalic acid-based polyester polyol manufactured by Toho Rikagaku Kogyo Co., Ltd. (modified with 15% trimethylolpropane), hydroxyl value 370, Hydroxy compound residual ratio 45% Polyol C: o-phthalic acid-based polyester polyol (modified by 15% trimethylolpropane) manufactured by Toho Rikagaku Kogyo Co., Ltd., hydroxyl value 370, hydroxy compound residual ratio 45% Polyol D: Toho Rikagaku ( Co., Ltd. p-phthalic acid-based polyester polyol (modified with 0% trimethylolpropane), hydroxyl value 250, hydroxy compound remaining rate 45% Polyol E: terephthalic acid-based polyester polyol (trimethylol pulp) manufactured by Toho Rika Kogyo KK Lopane 20% modified), hydroxyl value 420, hydroxyl compound residual ratio 45% Polyol F: terephthalic acid-based polyester polyol manufactured by Toho Rikagaku Kogyo Co., Ltd. (trimethylolpropane 5% modified), hydroxyl value 290, hydroxy compound residual ratio 45% Flame retardant: Tris-β-chloropropyl phosphate manufactured by Daihachi Chemical Co., Ltd. Foam stabilizer: “L5402” manufactured by Nippon Unicar Co., Ltd. Catalyst A: “Kaolyzer No. 1” manufactured by Kao Corporation Tetramethylhexamethylenediamine Catalyst B: "B-15G" manufactured by Nippon Kagaku Sangyo Co., Ltd. Potassium 2-ethylhexylate Blowing agent: "Diflon 141b" manufactured by Daikin Industries, Ltd. Dichloromonofluoroethane Polyisocyanate: Sumitomo Bayer Urethane Co., Ltd. crude diphenylmethane diisocyanate Formulation A and polyiso The Aneto determines the weight ratio as the isocyanate index is 200, was mixed with the solution temperature kept at 10 ° C., rotated by laboratory mixer number from 6000 to 9000
r. p. m. And foamed by stirring for 3 seconds, and the properties of the obtained foam were evaluated by the following methods. The results are shown in Table 1.

Flame retardancy: Based on JIS-A1321, each foam was sliced into 22 cm × 22 cm × 20 cm (thickness) and subjected to a surface test (heating time: 10 minutes).

Dimensional stability: 5 cm × 5 c from each foam
A cube of m × 5 cm was cut out and left under the condition of −5 ° C. × 24 hr, and the rate of change (%) in the width direction was determined.

Mechanical strength: 50 × 50 from the above foam
Cut out a cube of × 50 mm, and in the height direction,
The compressive strength was calculated from the stress at the time of compressing by mm.

[0037]

[Table 1]

Table 1 shows that the rigid polyurethane foam of the present invention using a specific polyester polyol compound as a polyol component is excellent in flame retardancy, dimensional stability and mechanical strength.

[0039]

As described in detail above, according to the rigid polyurethane foam of the present invention, a rigid polyurethane foam having excellent flame retardancy, good dimensional stability and good mechanical strength is provided.

Claims (3)

[Claims] 1. A rigid polyurethane foam obtained by mixing and foaming a polyisocyanate component and a blended liquid obtained by mixing a polyol component, a foaming agent, a catalyst, a foam stabilizer and other auxiliaries, wherein the polyol component comprises: It comprises one or more polybasic acid components selected from the group consisting of m-phthalic acid, p-phthalic acid, trimellitic acid and derivatives thereof, and a hydroxy compound component. The proportion of a hydroxy compound component having a functionality of at least 5% by weight or more, and the polyester component obtained by subjecting the polybasic acid component and the hydroxy compound component to an esterification reaction is contained in the polyol component in an amount of 3% by weight or more. Rigid polyurethane foam characterized by the above. 2. The rigid polyurethane foam according to claim 1, wherein the content of the tri- or higher functional hydroxy compound component in the hydroxy compound component is 10 to 50% by weight. 3. The rigid polyurethane foam according to claim 1, wherein the content of the polyester polyol compound in the polyol component is 15% by weight or more.