JPH07188375A - Rigid polyurethane foam - Google Patents

Abstract

PURPOSE:To obtain a rigid polyurethane foam having the same excellent heat insulating performance as that of a conventional rigid polyurethane foam pre pared by using CFC-11 by providing a resin solution having excellent storage stability by prescription using a substitute blowing agent, HCFC-141b, HCFC-123, etc. CONSTITUTION:In a rigid polyurethane foam produced by using 1,1-dichloro- fluoroethane (HCFC-141b) and/or 2,2-dichloro-1,1,1-trifluoroethane (HCFC-123) as a blowing agent, a polyol, component comprises >=30 pts.wt. of an aromatic polyester polyol, based on 100 pts.wt. of the polyol component, and 0.1-7 pts.wt. of a carboxylic acid metal salt based on 100 pts.wt. of the polyol component is used to give the objective rigid polyurethane foam.

Description

Detailed Description of the Invention

[0001]

This invention relates to rigid polyurethane foam. More specifically, a rigid polyurethane foam having excellent dimensional stability and productivity is expected to be widely used as a heat insulating material or heat insulating structural material for refrigerators, freezers, heat insulating panels, ships, vehicles and the like.

[0002]

BACKGROUND OF THE INVENTION Rigid polyurethane foams have heat insulating properties,
Because of its excellent low temperature dimensional stability and workability,
Widely used as a heat insulating material for frozen warehouses and building materials. This is because, when a rigid polyurethane foam is produced, trichlorofluoromethane (hereinafter referred to as R-11) having excellent filling properties and heat insulating properties is used as a foaming agent, and 100 parts by weight of polyol (hereinafter, parts are parts by weight). The reason is that 20 parts or more of R-11 is used. In recent years, regulations on chlorofluorocarbons have been implemented to protect the earth's ozone layer. R-11, which is used as a foaming agent for rigid polyurethane foam, is also included in this regulation. Therefore, there is an urgent need to develop a foaming agent for rigid polyurethane foam instead of R-11, and 1,1-dichloro-1-fluoroethane (hereinafter referred to as R-141b), 2,2-dichloro-1,1,1- Trifluoroethane (hereinafter R-
123) and the like are believed to be candidates for alternative blowing agents.

However, as a foaming agent, R-141b
Or, when R-123 is used, it is 1) worse in thermal conductivity than 2) which is foamed by using conventional R-11.
A satisfactory rigid polyurethane foam cannot be obtained because of problems such as deterioration of foaming efficiency, 3) deterioration of physical properties of foam such as dimensional stability at low temperature and compressive strength. In particular, when using rigid polyurethane foam as a heat insulating material in refrigerators, showcases, etc., it is required to have the same heat insulation performance as when R-11 is used, and the thermal conductivity peculiar to the foaming agent is R-11. When the same raw materials as in the past are used by using R-141b and R-123, which are inferior in comparison, the thermal conductivity of the rigid polyurethane foam is deteriorated, and the low temperature dimensional stability is further deteriorated. No polyurethane foam was obtained.

[0004]

In the past, various improvements have been made to rigid polyurethane foams in order to improve heat insulation performance. For example, JP-A-56-163117 succeeds in improving the thermal conductivity from 0.0150 to 0.0160 kcal / mhr ° C to 0.0130 to 0.0140 kcal / mhr ° C by using an aromatic amine polyol and a polyester polyol together. is doing. Further, JP-A-2-180916 has an average number of functional groups of 2.2.
~ 3.6 By using an aromatic polyester polyol having a hydroxyl value of 200 to 550 in an amount of 10 to 60% by weight of the polyol component, in addition to the thermal conductivity of the above technique, the resin strength has been successfully improved. However, all of these techniques use R-11, which is currently subject to CFC regulations as a blowing agent, or use a relatively large amount of water to reduce the amount of R-11 used, so-called saving. It is a CFC technology and is not suitable for the new R-141b and R-123.

The present inventors have previously found that the foaming agent R-141.
b, the method of obtaining the dimensional change rate and the compressive strength almost the same as the case of using the conventional R-11 is invented even when R-123 is used. These are as described in JP-A-1-287125 and JP-A-3-86735, but this method is not always satisfactory in terms of heat insulation performance as compared with the case of using R-11. Was not. Also,
In Japanese Patent Application No. 5-138131, R-141b and R-123 are used as a foaming agent, and aromatic polyester polyol obtained by reacting o-phthalic acid or phthalic anhydride with glycerin and ethylene glycol is used. Although it was described that a rigid polyurethane foam excellent in heat insulation performance (low thermal conductivity) almost equal to that of the conventional rigid polyurethane foam obtained by using the above was obtained, some problems were found in the stability of the resin liquid.

[0006]

DISCLOSURE OF THE INVENTION As a result of intensive studies to solve the above problems, the present inventors have found that a storage solution that is stable in storage when R-141b and R-123 are used as a foaming agent. The present invention has been accomplished by finding a method for producing a rigid polyurethane foam having excellent heat insulation performance. That is, the present invention is an organic polyisocyanate,
R-14 with polyol, catalyst, foam stabilizer and other auxiliaries
1b and / or R-123 in a rigid polyurethane foam produced by foaming in the presence of a foaming agent, as a polyol component, 30 parts by weight or more per 100 parts by weight of a polyol is an aromatic polyester polyol, and has the general formula R-COO. -X (wherein R is an alkyl group, an alkenyl group, or an aryl group having 1 to 17 carbon atoms,
X represents sodium or potassium. ) 1
It is a rigid polyurethane foam characterized by containing 0.1 to 7 parts by weight per 100 parts by weight of a polyol, or two or more kinds of carboxylic acid metal salts.

Instead of the conventionally used R-11, R-
When 123 or R-141b is used, according to the present invention, for the first time, a rigid urethane foam which is a storage-stable resin liquid and has excellent heat insulating performance can be obtained. The aromatic polyester polyol used in the present invention has a hydroxyl value of 300 to 60.
0 preferably 350 to 550, more preferably 400 to 550
550, and the number of copies used is 30 or more.

In the present invention, the carboxylic acid metal salt which can be used in common with the aromatic polyester polyol is represented by the general formula RC
It is represented by OO-X. In the formula, R is an alkyl group having 1 to 17 carbon atoms, an alkenyl group, or an aryl group,
X is sodium or potassium. 1 carbon atom in R
When it is 8 or more, it becomes difficult to dissolve in water and is not practical, and potassium octoate and / or potassium acetate are preferable. The amount used is 0.1 per 100 parts by weight of polyol.
It can be used in the range of 7 to 7 parts by weight, preferably 0.1 to 2 parts by weight. If it is less than 0.1 part by weight, it will separate after 2 days from the preparation of the resin solution, and if it exceeds 7 parts by weight, the reactivity or the curing rate will be too fast, which is not practical.

In the present invention, the polyol which can be used in combination with the aromatic polyester polyol is all polyols which are usually used as a urethane raw material. Polyols normally used as urethane raw materials are, for example,
Propylene oxide or ethylene oxide added to polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, trimethylolpropane, pentaerythritol, sorbitol and sucrose. Aromatic tolylenediamine, aliphatic ethylenediamine to which propylene oxide and ethylene oxide are added, and the like, and polyester polyols include aliphatic polyester polyols and the like. And
These polyether polyols and aliphatic polyester polyols may be used in combination.

The organic polyisocyanate used in the present invention is an organic compound having two or more isocyanate groups in one molecule, and is an aliphatic or aromatic polyisocyanate compound, and further these compounds. Includes modified products of. Examples of aromatic polyisocyanates include tolylene diisocyanate, diphenylmethane diisocyanate, and polymeric diphenylmethane diisocyanate, and examples of aliphatic polyisocyanates include:
There are hexamethylene diisocyanate, isophorone diisocyanate and the like, and modified products thereof include a carbodiimide modified product and a prepolymer modified product. Preferred organic polyisocyanates in the present invention are aromatic polyisocyanates or modified products of aromatic polyisocyanates, particularly preferably diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanates and modified products thereof.

As the catalyst, for example, amine-based urethane-forming catalysts such as trimethylaminoethylpiperazine, triethylamine, tripropylamine, N-methylmorpholine, N-ethylmorpholine, triethylenediamine and tetramethylhexamethylenediamine can be used.
These catalysts can be used alone or as a mixture, and the amount thereof is appropriately 0.001 to 10.0 parts by weight with respect to 100 parts by weight of the compound having active hydrogen.

As the foam stabilizer, a conventionally known organosilicon surfactant is used. For example, L-5420, L-5340, SZ-1645, SZ- manufactured by Nippon Unicar Co., Ltd.
1627, F-343, F- manufactured by Shin-Etsu Chemical Co., Ltd.
347, F-350S, F-345, F-348, etc. are suitable. The appropriate amount of these foam stabilizers is 0.1 to 10.0 parts by weight with respect to 100 parts by weight of the compound having active hydrogen. Other flame retardants, plasticizers, stabilizers, colorants and the like can be added as required.

To carry out the present invention, a predetermined amount of a polyol, a foaming agent, a catalyst and a foam stabilizer is mixed to form a resin solution. The resin solution and the organic polyisocyanate are mixed at a high ratio at a high speed and poured into a void or a mold. At this time, the liquid ratio of the organic polyisocyanate and the resin liquid is adjusted so that the equivalent ratio (NCO: H) of the organic polyisocyanate and the active hydrogen of the resin liquid is 0.7: 1 to 5: 1. .

[0014]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Parts in the examples represent parts by weight. Isocyanate A: Mitsui Toatsu Chemical Co., Ltd. Polymeric MDI All NCO 31.3% Aromatic polyester polyol A: Phthalic anhydride 148
g, ethylene glycol 62 g, and glycerin 92 g were reacted at 200 to 230 ° C. with stirring in the flask. Hydroxyl value 540, viscosity 30,000 CPS / 25 ℃. Aromatic polyester polyol B: 166 g of o-phthalic acid
And 62 g of ethylene glycol and 92 g of glycerin were reacted at 200 to 230 ° C. while stirring in the flask. Hydroxyl value 540, viscosity 28,000 CPS / 25 ℃. Polyetherpolyol A: Hydroxyl value obtained by adding propylene oxide to a mixture of sorbitol / glycerin 450
mgKOH / g polyether polyol Foam stabilizer: L-5420 manufactured by Nippon Unicar Co., Ltd. Catalyst: Tetramethylhexamethylenediamine Foaming agent: R-141b, R-123

Examples 1 to 9 A predetermined amount of the polyol, the foaming agent, the foam stabilizer and the catalyst shown in Tables 1 and 2 were mixed in advance to prepare a resin solution. After allowing these resin solutions to stand at 23 ° C. for 14 days, add a predetermined amount of organic polyisocyanate, mix them for 8 seconds at high speed, and immediately foam into a free foaming box (size: 250 × 250 × 250 mm wooden box). The liquid was injected. In addition, the vertical aluminum panel pre-adjusted to 45 ° C (size: internal dimensions 400 x 400 x 3
A predetermined amount of the foaming liquid was poured into the plate (0 thickness mm), and after 6 minutes, the foam was released from the mold. The properties of the resin solution after 14 days and various characteristic values of the obtained rigid polyurethane foam are shown in Tables 1 and 2.
Shown in.

[0016]

[Table 1]

[0017]

[Table 2]

The measuring conditions of various physical properties of the rigid polyurethane foam are as follows. Free density: The density of the core part of the foam obtained by free foaming. (Unit: kg / m ³ ) Dimensional stability: The dimensional stability was measured after the foam obtained from the aluminum vertical panel was left standing for 24 hours. It is the volume change rate of the core part of the foam after standing still in a low temperature tank at -30 ° C for 48 hours. (Unit:%) Thermal conductivity: One day after demolding the rigid polyurethane foam,
The thermal conductivity of the core portion (size: 200 × 200 × 25 thickness mm) of the foam obtained from the vertical aluminum panel was measured with an Eihiro Seiki Auto λ measuring machine. (Unit: kca
1 / mhr ° C)

Comparative Examples 1 to 8 In the same manner as in Examples, a rigid polyurethane foam was obtained by reacting a resin solution after standing at 23 ° C. for 14 days with a predetermined amount of organic polyisocyanate. Properties of the resin solution after 14 days and various characteristic values of the obtained rigid polyurethane foam are shown in Tables 3 and 4. Various physical properties of the rigid polyurethane foam having coarse cells were not measured.

[0020]

[Table 3]

[0021]

[Table 4]

From the examples of Tables 1 and 2 and the comparative examples of Tables 3 and 4, resin solutions containing 0.1 parts by weight or more of potassium octanoate or potassium acetate per 100 parts by weight of polyol (Examples 1 to 9, Comparative Examples 3, 4, 6) were transparent and did not separate even after 14 days from the preparation of the resin solution. These resin solutions did not separate even after 2 months. Moreover, the obtained rigid polyurethane foam was not particularly inferior to the conventional R-11 formulation (Comparative Example 8). However, less than 0.1 parts by weight per 100 parts by weight of polyol (Comparative Examples 1, 2, 5, and 7) was not practical because it separated after 2 days of resin preparation. Further, if it exceeds 7 parts by weight per 100 parts by weight of the polyol, the reactivity rate or the curing rate becomes too fast, which is not practical.

[0023]

The rigid polyurethane foam obtained by the formulation using the alternative blowing agents R-141b and R-123 is compared with the rigid polyurethane foam obtained by the formulation using a large amount of conventional R-11. The heat insulation performance (thermal conductivity) of the rigid polyurethane foam was extremely poor. In addition, when the aromatic polyester polyol is used in the presence of R-141b and R-123, the stability of the resin solution is poor. However, according to the present invention, when an aromatic polyester polyol is used as an organic polyol component, and a metal salt is used in combination, a storage solution that is stable in storage is obtained, and a rigid polyurethane foam obtained from this resin solution has a conventional R-value. It was not particularly inferior to the rigid polyurethane foam obtained from the 11 formulations.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location C08L 75:04 (72) Inventor Hiroshi Fujino 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd. In-house (72) Inventor Yuji Uchida 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd.

Claims (3)

[Claims] 1. An organic polyisocyanate, a polyol,
Catalyst, foam stabilizer and other auxiliaries were added to 1,1-dichloro-1
-Fluoroethane and / or 2,2-dichloro-1,
In a rigid polyurethane foam produced by foaming in the presence of a 1,1-trifluoroethane blowing agent, 30 parts by weight or more per 100 parts by weight of the polyol is an aromatic polyester polyol, and 100 parts by weight of the polyol is generally used. One or two or more kinds of carvone represented by the formula R-COO-X (wherein R represents an alkyl group, an alkenyl group or an aryl group having 1 to 17 carbon atoms, and X represents sodium or potassium). Acid metal salt,
A rigid polyurethane foam characterized by containing 0.1 to 7 parts by weight. 2. The aromatic polyester polyol is o-
The rigid polyurethane foam according to claim 1, which has an average number of functional groups of 3 or more and a hydroxyl value of 300 to 600, which is obtained by reacting phthalic acid and / or phthalic anhydride with glycerin and / or ethylene glycol. 3. The rigid polyurethane foam according to claim 1, wherein the carboxylic acid metal salt is potassium octanoate and / or potassium acetate, and the content thereof is 0.1 to 2 parts by weight in 100 parts by weight of the polyol. .