JPH06306132A - Production of urethane-modified polyisocyanurate foam - Google Patents

Abstract

PURPOSE:To obtain the foam excellent in flame retardancy and adhesion even at a low temperature by incorporating three specified compounds into a mixture of a polyisocyanate component and a polyol component consisting of a polyol and other ingredients before foaming the mixture. CONSTITUTION:A process for producing a urethane-modi fied polyisocyanurate foam by mixing a polyisocyanate component and a polyol component consisting of a polyol, a catalyst, a flame retardant, a foaming agent and a foam stabilizer and foaming the mixture, wherein ethylene carbonate, propylene carbonate and methyl formate are used as additives. It is desirable that the amounts of ethylene carbonate, propylene carbonate and methyl formate to be added are respectively 1.0-5.0 pts.wt., 0.1-2.0 pts.wt. and 0.3-3.0 pts.wt. based on 100 pts.wt. polyol and that a polyol containing an aromatic polyester polyol in an amount of 50-90wt.% 1 is used as the polyol.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a urethane-modified polyisocyanurate foam excellent in flame retardancy and adhesiveness.

[0002]

2. Description of the Prior Art It is known to react polyisocyanates in the presence of trimerization catalysts to produce polyisocyanurate foams. However, since polyisocyanurate foam is extremely high in brittleness, it is usually considered as a urethane-modified polyisocyanurate foam in which a urethane bond is introduced by using a polyol. When producing urethane-modified polyisocyanurate foam, NCO is usually used.
The polyisocyanate component and the polyol component are blended so that the / OH equivalent ratio becomes about 2.0 or more. The smaller the amount of the polyol used, the smaller the brittleness improving effect, and conversely, the larger the amount of the polyol used, the flame retardancy. Is reduced.

Further, when an aromatic polyester polyol is used, a urethane-modified polyisocyanurate foam excellent in flame retardancy can be obtained even if the NCO / OH equivalent ratio is relatively small (that is, the polyol is used in a large amount). This is well known. The urethane-modified polyisocyanurate foam obtained by using this aromatic polyester polyol is widely used as a heat insulating material such as so-called continuous laminate board integrally foamed with a surface material such as gypsum board. In this case, it is common to heat the surface material in order to improve the adhesion between the urethane-modified polyisocyanurate foam and the surface material and to complete the trimerization.

However, in the case of on-site spray foaming in which a polyisocyanate component and a polyol component consisting of a polyol, a trimerization catalyst, other additives, etc. are mixed to perform spray foaming, the temperature of the body (spray foaming target) is controlled. It is difficult to adjust. When urethane-modified polyisocyanurate foam is spray-foamed on-site, especially when spray-foaming is comparatively thin, heat is insufficient due to heat absorption by the skeleton and the degree of completion of trimerization is low. It is difficult for the modified polyisocyanurate foam to exhibit its inherent flame retardancy, and when the temperature during the reaction is low, the trimerization reaction is delayed compared to the urethanization reaction, and so-called two-stage foaming occurs, so the foam cures. Immediately before the above, there is a problem that a parallel elongation phenomenon occurs along the surface of the body, a lateral elongation phenomenon occurs, and curing slows down, and the adhesiveness between the foam and the body is significantly reduced. Therefore, the body temperature is 1
Below 0 ° C, it was not possible to spray foam urethane-modified polyisocyanurate foam in situ.

[0005]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted extensive studies to solve these problems, and as a result, have excellent adhesiveness even during spray foaming at low temperatures, and JIS A
We have developed a method for producing urethane-modified polyisocyanurate foams that pass Class 3 flame retardancy in a flame retardancy test according to 1321.

That is, the object of the present invention is to exhibit excellent reactivity even at a low temperature of 10 ° C. or lower, and particularly to the trimerization even in a comparatively thin spray foaming or spray foaming when the body temperature is extremely low such as 0 ° C. It is an object of the present invention to provide a method for producing a urethane-modified polyisocyanurate foam that has a high degree of completion and excellent flame retardancy, and that also has excellent adhesiveness without causing two-stage foaming.

[0007]

According to the present invention, an aromatic polyester polyol is mainly used as a polyol, and ethylene carbonate, propylene carbonate, and methyl formate are used in combination, so that flame retardancy and adhesion can be achieved even at a low temperature. The present invention has been completed by finding that a urethane-modified polyisocyanurate foam having excellent properties can be formed.

That is, the present invention provides a method for producing a urethane-modified polyisocyanurate foam in which a polyisocyanate component and a polyol component comprising a polyol, a catalyst, a flame retardant, a foaming agent, and a foam stabilizer are mixed and foamed. , Propylene carbonate and methyl formate are used, and ethylene carbonate is 1.0 to 5.0 parts by weight, propylene carbonate is 0.1 to 2.0 parts by weight, and methyl formate is 0.1 to 100 parts by weight of the polyol.
A method for producing a urethane-modified polyisocyanurate foam, which comprises using 3 to 3.0 parts by weight and using, as the polyol, a polyol containing 50 to 90% by weight of an aromatic polyester polyol with respect to the total amount of the polyol. is there.

Examples of the polyol used in the present invention include those obtained by mixing an aromatic polyester polyol, a polyether polyol and the like, and the aromatic polyester polyol is preferably 50 to 9 with respect to the total polyol.
The mixture is used in an amount of 0% by weight, more preferably 50 to 80% by weight. When the amount of the aromatic polyester polyol used is less than 50% by weight, it may be difficult to pass the JIS A 1321 test as flame retardant class 3. On the other hand, when it exceeds 90% by weight,
The formed urethane-modified polyisocyanurate foam may have poor dimensional stability. Examples of this aromatic polyester polyol include polyethylene terephthalate scrap, dimethyl terephthalate process residue, polyol made from phthalic acid and the like, and the hydroxyl value of these is usually 200 to 500 mgKOH / g.
A degree is preferable.

As the polyisocyanate component used in the present invention, aromatic or aliphatic polyisocyanates can be used alone or in combination, but it is preferable to use only aromatic polyisocyanates. . Aromatic polyisocyanates include, but are not limited to, polymethylene polyphenyl polyisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, and the like.

In the present invention, the polyisocyanate component and the polyol component have an NCO / OH equivalent ratio of 1.5 to.
It is preferable to mix it so as to be 3.0, and it is more preferable to mix it so as to be 1.8 to 2.7. NCO / OH
If the equivalent ratio is less than 1.5, it may be difficult to pass the Class 3 flame-retardant test according to JIS A 1321. On the other hand, if it is higher than 3.0, it becomes highly brittle and at the same time a so-called lateral elongation phenomenon occurs, resulting in poor adhesion. It may decrease.

The present invention is characterized in that ethylene carbonate, propylene carbonate and methyl formate are used in combination, and these are mixed and used as a polyol component. It is preferable to use three kinds of ethylene carbonate, propylene carbonate and methyl formate in combination. The amount of each of these used is 1.0 part of ethylene carbonate with respect to 100 parts by weight of polyol.
~ 5.0 parts by weight, propylene carbonate 0.1 ~
2.0 parts by weight and 0.3 to 3.0 parts by weight of methyl formate are preferred. The amounts of ethylene carbonate, propylene carbonate and methyl formate used were 1.0, 0.1,
If the amount is less than 0.3 parts by weight, the smoke emission coefficient may become too large in the adhesiveness and the flame retardancy test according to JIS A 1321, and the amount used is 5.0, 2.0, respectively.
If it exceeds 3.0 parts by weight, the dimensional stability of the formed foam may be deteriorated.

The total amount of the three kinds of ethylene carbonate, propylene carbonate and methyl formate used is 1.4 to 10 parts by weight, preferably 2.0 to 6.0 parts by weight, based on 100 parts by weight of the polyol. is there.

Examples of the catalyst used in the present invention include alkali metal salts of carboxylic acids, lead compounds and s-triazine compounds, which can be used in combination. Examples of the alkali metal salt of carboxylic acid include potassium octylate and potassium acetate, and examples of the lead compound include lead octylate and lead naphthenate. Examples of the s-triazine compound include N, N ′, N ″ -tris (diaminopropyl) hexahydro-s-triazine.

As the flame retardant which can be used in the present invention, a phosphorus-halogen flame retardant can be used. Examples thereof include tris (chloroethyl) phosphate and tris (chloropropyl) phosphate. 10 to 30 parts by weight is preferable with respect to parts by weight. If the amount of this flame retardant used is less than 10 parts by weight, the flame retardancy may be poor and the foam may burn. If it exceeds 30 parts by weight.
In the flame retardancy test according to JIS A 1321, the smoke emission coefficient may be high.

Examples of the foaming agent in the present invention include trichloromonofluoromethane, methylene chloride, water and the like. These foaming agents are mixed in advance with a polyol component and / or a polyisocyanate component, and the polyol component and the polyisocyanate component are mixed under high pressure with a mixing head to perform spray foaming, thereby forming a urethane-modified polyisocyanurate foam. Can be manufactured.

In the present invention, it is also possible to employ a floss spray method in which a foaming agent which is liquid at room temperature and atmospheric pressure is used in combination with a foaming agent which has a boiling point of 5 ° C. or lower and is gas at room temperature and atmospheric pressure. According to the floss spray method, which uses a foaming agent that has a boiling point of 5 ° C or less at room temperature and atmospheric pressure as a foaming agent, both the polyol component and the polyisocyanate component mixed by the mixing head are discharged from the spray gun. Since the pressure becomes normal pressure, the temporary foaming agent is instantly vaporized and the foaming stock solution is discharged from the tip of the spray gun in a foamed state. In this way, the foaming undiluted solution is foamed before adhering to the skeleton, so it is unlikely to be affected by the properties and temperature of the skeleton, and even if the skeleton temperature is low, the degree of completion of trimerization due to the heat absorption of the skeleton is reduced. The lateral elongation phenomenon can be prevented. Combined with the use of the above-mentioned three specific catalysts, the adhesion at low temperature can be further improved. Examples of the foaming agent having a boiling point of 5 ° C. or lower at room temperature and atmospheric pressure include dichlorofluoromethane, monochloromonofluoromethane, dichlorotetrafluoromethane and the like.

In the method for producing the urethane-modified polyisocyanurate foam of the present invention, any other additive may be used. In order to form a particularly good foam, it is preferable to use a silicone type foam stabilizer as used in the production of polyurethane foam. In addition, known additives such as flame retardants, colorants, fillers and stabilizers can be used as necessary.

[0019]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples. Examples 1 to 5 and Comparative Examples 1 to 3 The polyisocyanate component, the aromatic polyester polyol, the polyether polyol, the foam stabilizer, the catalyst, the flame retardant, and the foam stabilizer shown in Table 1 are used as raw material components, and 450 m in length.
m, width 450 mm, thickness 6 mm, and slate plate having a body temperature of 0 ° C. were spray-foamed with Gasmer Model FF1600 (manufactured by Gasmer) to a thickness of 25 mm. The temperature of each of the polyisocyanate component and the polyol component is 45 ° C. Each was subjected to a physical property test and a flame retardancy test. The results are also shown in Table 1.

[0020]

[Table 1]

[0021]

[Description of table]

* 1 Polymethylene polyphenyl polyisocyanate NCO% = 32 * 2 Aromatic polyester polyol Hydroxyl value = 260 * 3 Polyether polyol Hydroxyl value = 500 * 4 Foam stabilizer Silicone foam stabilizer * 5 Catalyst N, N ', N " -(Trisdimethylaminopropyl) -S
-Hexahydrotriamine and potassium octylate 4
Mix at 0:60 * 6 Flame retardant tris (β-chloroisopropyl) phosphate * 7 Blowing agent trichloromonofluoromethane * 8 Compliant with JIS A 9514 * 9 Compliant with JIS A 1321 ○ ・ ・ ・ Passes flame retardant class 3 × ・ ・ ・ Failed in flame retardant grade 3

[0022]

As described above, according to the method of the present invention, the object to be adhered has a low temperature such as 0 ° C., which has the flame retardancy that passes the flame retardant class 3 test based on JIS A 1321. However, it is possible to form a urethane-modified polyisocyanurate foam having excellent adhesiveness.

Claims (3)

[Claims] 1. A polyisocyanate component and a polyol,
In a method for producing a urethane-modified polyisocyanurate foam in which a catalyst, a flame retardant, a foaming agent, and a polyol component consisting of a foam stabilizer are mixed and foamed, ethylene carbonate, propylene carbonate, and methyl formate are used as the urethane. A method for producing a modified polyisocyanurate foam. 2. Ethylene carbonate is 1.0 to 5.0 parts by weight, propylene carbonate is 0.1 to 2.0 parts by weight, and methyl formate is 0.3 parts with respect to 100 parts by weight of polyol.
The method for producing a urethane-modified polyisocyanurate foam according to claim 1, wherein the amount is 3.0 to 3.0 parts by weight. 3. The urethane-modified polyisocyanurate foam according to claim 1, wherein a polyol containing 50 to 90% by weight of the aromatic polyester polyol is used as the polyol. Production method.