JP2001200028A - Low flammability polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible polyurethane foam having lower flammability than conventional ones and having less molten droplets during combustion. SOLUTION: In a flexible polyurethane foam obtained by reacting a polyol component and a polyisocyanate component in the presence of additives including a foaming agent, a foam stabilizer, a catalyst and a flame retardant, the polyisocyanate has an NCO index of 1. MDI in an amount of 8 to 3.0, the flame retardant is 70 parts by weight or more of the melamine resin and 30 to 70 parts by weight of the organophosphorus flame retardant and the foam stabilizer are 0.1 to 100 parts by weight of the polyol component. 2.5 parts by weight of a low-flammability flexible polyurethane foam which is a dimethylpolysiloxane-polyoxyalkylene copolymer having a polyether terminal OH. The catalyst is 0.
1 to 2.0 parts by weight of potassium octylate, or 0.1 to 2.0 parts by weight
The above polyurethane foam, which is a combination system of 1.5 parts by weight of potassium octylate and 0.1 to 3.0 parts by weight of an amine catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a low-flammability flexible polyurethane foam.

[0002]

2. Description of the Related Art Conventionally, flexible polyurethane foams have been used for a wide range of applications including cushioning materials, mattresses, etc., and are used after imparting low flammability according to each application. As a method of reducing the burning of the flexible polyurethane foam, a method of blending an organic phosphorus-based flame retardant in a raw material and a method of blending an inorganic compound such as aluminum hydroxide or antimony trioxide in a raw material are often used. In addition, a method of imparting low flammability by post-processing, for example, impregnation with an inorganic substance, is also used.

In recent years, flexible polyurethane foams have been
It has also been used as a member of equipment and a member for electric appliances, and low flammability according to the application is required. As an index of the flammability when used as a member for electric appliances, a material combustion test for electrical use in the United States (UL-94) is often used. In this standard, it is required to reduce the amount of drippings during foam combustion as much as possible. One of the points in meeting this standard is the ease of foam carbonization. That is, it is required to reduce as much as possible the molten dripping material during the combustion of the foam.

The above organophosphorus flame retardants, for example, TCEP
(Tris (chloroethyl) phosphate), TCPP (tris (chloropropyl) phosphate), TCP (tricresylphosphate) and the like are addition-type flame retardants that do not have active hydrogen that reacts with isocyanate groups. It has no effect, is liquid and easy to use, and has a high flame retardant effect.However, there are many molten drops during combustion, and the flame retardant alone is not only urethane foam alone, but also urethane foam and flame retardant fiber material in the case where a combination of such well, it is difficult to clear the UL standard, in particular UL-94 a (V ₀ ~V _2). It is also conceivable to use an inorganic flame retardant, for example, aluminum hydroxide, antimony trioxide, zinc oxide, etc. However, the viscosity of the raw material system is remarkably increased, and it is often impossible to sufficiently supply the raw material system. In addition,
The provision of flame retardancy by post-processing also has the disadvantage of lower productivity.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a flexible polyurethane foam having lower flammability and less molten drops during combustion than conventional ones.

[0006]

The present invention provides a flexible polyurethane foam obtained by reacting a polyol component and a polyisocyanate component in the presence of additives including a foaming agent, a foam stabilizer, a catalyst and a flame retardant. The polyisocyanate is a diphenylmethane diisocyanate (MDI) having an NCO index of 1.8 to 3.0, and the flame retardant is at least 70 parts by weight of a melamine resin and 30 to 70 parts by weight based on 100 parts by weight of a polyol component. The organophosphorus flame retardant and the foam stabilizer are dimethylpolysiloxane-polyoxyalkylene copolymers having a polyether terminal OH of 0.1 to 2.5 parts by weight based on 100 parts by weight of the polyol component. The present invention relates to a low-flammability flexible polyurethane foam characterized by the above. In another embodiment, the present invention relates to the above composition, wherein the catalyst is 0.1 to 2.0 parts by weight of potassium octylate or 0.1 to 2.0 parts by weight of octylic acid per 100 parts by weight of the polyol component. Potassium and 0.1 to 3.
The present invention relates to a low-combustibility flexible polyurethane foam which is a combination system of 0 parts by weight of an amine catalyst. In still another aspect, the present invention relates to a low-flammability flexible polyurethane foam further comprising 0.1 to 2.0 parts by weight of a foaming agent based on 100 parts by weight of a polyol component, in addition to any one of the above-mentioned compositions.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The polyol used in the present invention is not particularly limited, and may be polyether polyol, polyester polyol, polyether ester polyol,
Polyacryl polyol and the like can be used. A polyether polyol is preferable, and a material having a molecular weight of 4,000 or more and a high reactivity is particularly useful in order to express the cushioning characteristic of a flexible polyurethane. Polyether polyols having a primary terminal OH are particularly preferred.

[0008] The polyisocyanate that can be used in the present invention is diphenylmethane diisocyanate (hereinafter abbreviated as MDI). In a flexible polyurethane foam, tolylene diisocyanate (hereinafter, also abbreviated as TDI) is generally used as a polyisocyanate component, but in the present invention, MDI is used in order to promote carbonization of the foam during combustion. Among them, polymeric MDI is particularly preferred in that it reduces the amount of melted drops during combustion. Here, polymeric MDI refers to MDI as described on page 75 of "Polyurethane Handbook" (edited by Keiji Iwata, published by Nikkan Kogyo Shimbun, 1987).
And a mixture of MDI oligomers that are polynuclear and polyfunctionalized from MDI. Such a polymeric MDI
Is available as a commercial product, for example, "MR-200"
(Manufactured by Nippon Polyurethane Industry Co., Ltd.). In addition, other polyisocyanates such as TDI, IPDI (isophorone diisocyanate) and HDI (hexamethylene diisocyanate) can be mixed as long as the low flammability aimed at by the present invention can be maintained.

[0009] The compounding amount of the polyisocyanate is such that the NCO index is 1.8 to 3.0, preferably 1.8 to 2.5. In a general flexible polyurethane foam, the NCO index is usually set to 0.8 to 1.2, but in the present invention, the NCO index is set to fall within the above range in order to improve heat resistance. When a polyisocyanate other than MDI is mixed, the above NCO index range covers all isocyanate groups. In the above, NC
What is the O index

(Equation 1) Is the value represented by

In the present invention, a melamine resin and an organic phosphorus-based flame retardant are used in combination as the flame retardant. The amount of the melamine resin is 70 parts by weight or more based on 100 parts by weight of the polyol.
Preferably from 70 to 150 parts by weight, more preferably from 80 to
120 parts by weight. The melamine resin has a carbonization promoting effect and does not increase the viscosity of the raw material system unlike the inorganic flame retardant, so that the above-mentioned amount effective for promoting carbonization can be added. However, since melamine resin alone is insufficient in the effect of suppressing fire spread, an organic phosphorus-based flame retardant is used in combination. If the amount of the organic phosphorus-based flame retardant is too large, the amount of the melted drop tends to increase. Therefore, the compounding amount is preferably 30 to 70 parts by weight based on 100 parts by weight of the polyol. The ratio of the melamine resin and the organophosphorus flame retardant does not matter in particular, and each may be blended in the above range.

As the organophosphorous flame retardant that can be used in the present invention, the organophosphorous flame retardant conventionally used for flame retarding polyurethane foam can be used.
P, TCPP, TCP and the like can be exemplified. In particular, TCEP tends to easily carbonize, and is preferable when used in combination with a melamine resin.

The foam stabilizer is used to adjust the size and uniformity of the cells of the polyurethane foam, the continuity of the cells, the thickness of the cell walls and the like to an appropriate state. In the present invention, among the foam stabilizers conventionally used in the production of polyurethane foam, a dimethylpolysiloxane-polyoxyalkylene copolymer having an OH group at the side chain polyether terminal is used. This is to contribute to the improvement of the flame retardancy. A general foam stabilizer used for a flexible polyurethane foam has an alkyl group at a side chain polyether terminal, but in the present invention, a foam stabilizer having a terminal OH group is used. In particular, those having a ratio of EO (ethylene oxide) / PO (propylene oxide) of 100/0 in the polyether portion are preferable from the viewpoint of improving the flame retardancy. The amount of addition is 0.1 to 2.5 parts by weight based on 100 parts by weight of the polyol component. The amount is particularly preferably 0.2 to 0.8 part by weight from the viewpoint of foam stability.

Further, in the present invention, in order to prevent shrinkage during foaming, it is preferable to use a foaming agent in combination. As the foam breaker, a foam stabilizer having high foam breaking properties, for example, among the above-mentioned dimethylpolysiloxane-polyoxyalkylene copolymers, may be used as the foam breaker. The foaming agent is used in an amount of 0.1 to 2.0 parts by weight, preferably 0.3 to 0.3 parts by weight, per 100 parts by weight of the polyol component.
It is added in the range of 8 parts by weight. It should be noted that other foam stabilizers may be added as long as the low flammability characteristic of the present invention can be maintained.

The catalyst used in the present invention is not particularly limited, and triethylenediamine, triethylamine, tetramethylhexamethylenediamine, N-ethylmorpholine, dimethylaminoethoxyethoxyethanol, bis-diamine, which are usually used in the production of flexible polyurethane foams, can be used.
Amine catalysts such as-(dimethylaminoethyl) ether, pentamethyldiethylenetriamine, tetramethylpropylenetriamine, 1,2-dimethylimidazole, tris (dimethylaminopropyl) -hexahydro-S-triazine, potassium octylate, dibutyltin dilaurate; Any metal-based catalyst such as stannas octate can be used. Preferably, potassium octylate or a combination of potassium octylate and an amine catalyst is used. In the present invention, since the reaction is carried out with the NCO index in the range of 1.8 to 3.0, the initial cure is very important, and potassium octylate is extremely useful in improving the initial cure. The preferred range of the amount of potassium octylate added is 0.1 to 100 parts by weight of the polyol.
It is from 1 to 2.0, especially from 0.3 to 0.8 parts by weight. The amount of the amine catalyst used in combination with potassium octylate is 0.1.
It is 1 to 3.0 parts by weight, preferably 0.5 to 1.5 parts by weight.

In the production of the low-flammability flexible polyurethane foam of the present invention, those used in the production of conventional flexible polyurethane foams can be used as the foaming agent. Such a blowing agent can be used alone or in combination with water and a compound having a low boiling point. Examples of the low boiling point compound include a fluorocarbon compound such as trichloromonofluoromethane and dichlorodifluoromethane, and dichloromethane. The amount of the foaming agent to be used can be determined in the same manner as in the conventionally known method in consideration of the density of the foam, general physical properties, the exothermic temperature during the reaction, and the like.

In the present invention, in addition to the above additives, if necessary, a coloring agent such as a pigment, an antioxidant, an ultraviolet absorber, a light stabilizer, a conductive substance such as carbon black,
Other additives such as antimicrobial agents and various fillers can be added. These additives are preferably added to and mixed with the polyol component at the raw material stage. The foam structure of the flexible polyurethane foam of the present invention is not particularly limited.

[0017]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. In Examples and Comparative Examples, the amounts of the raw material components of the polyurethane foam mean parts by weight based on 100 parts by weight of the polyol component, unless otherwise specified. Example 1 100 parts by weight of a polyether polyol (manufactured by Asahi Glass Co., Ltd., "EL823") was used as a polyol, and 62.9 parts by weight of polymeric MDI (manufactured by Nippon Polyurethane Industry Co., Ltd., "MR-200") was used as an isocyanate. At this time, the NCO index was 2.2. Further, 1.5 parts by weight of water and 13 parts by weight of dichloromethane were used in combination as a foaming agent. As a flame retardant, 100 parts by weight of melamine resin (manufactured by Nissan Chemical Co., Ltd., “Melamine”) and 50 parts by weight of TCEP (manufactured by Daihachi Chemical Industry Co., Ltd.) were used in combination. The catalyst is bis (dimethylaminoethyl) as an amine-based catalyst.
Ether DPG solution (Toyocat E manufactured by Tosoh Corporation)
T "), 0.2 parts by weight of tetraethylenediamine (" TEDA L-33 "manufactured by Tosoh Corporation) and 0.3 parts by weight of potassium octylate as a metal catalyst in a DEG solution (" PCAT 15G "manufactured by Nippon Chemical Industry Co., Ltd.) Was used in an amount of 0.6 parts by weight. As a foam stabilizer, 0.4 parts by weight of a silicone foam stabilizer (“SH193” manufactured by Dow Corning Toray Co., Ltd.) having polyoxyethylene having an OH group at its end as a side chain was used. Furthermore, "Y682" manufactured by Nippon Unicar Co., Ltd.
0.6 "by weight was used. In the above formulation, all the additives were stirred and mixed in the polyol and then mixed with the isocyanate to obtain a flexible polyurethane foam having a density of 110.4 kg / m ³ .

Comparative Example 1 A flexible polyurethane having a density of 110.9 kg / m ^{3 was} prepared in the same manner as in Example 1 except that 150 parts by weight of the same kind of melamine resin was used alone as a flame retardant instead of using melamine resin and TCEP together. Got the form.

Comparative Example 2 A flexible polyurethane foam having a density of 83.5 kg / m ³ was obtained in the same manner as in Example 1 except that 70 parts by weight of TCEP was used alone as a flame retardant instead of using a melamine resin and TCEP in combination. .

Comparative Example 3 A density of 9 was obtained in the same manner as in Example 1 except that polymeric MDI was used in such an amount that the NCO index became 1.1.
A flexible polyurethane foam of 9.8 kg / m ³ was obtained.

COMPARATIVE EXAMPLE 4 As a foam stabilizer, instead of "SH193", an EO (ethylene oxide) / PO (propylene oxide) copolymer having a polyether terminal having an alkyl group and a polyether portion having a molar ratio of 50/50 was used. Silicone foam stabilizer (“SH190” manufactured by Dow Corning Toray Silicone Co., Ltd.)
Except that 0.4 part by weight was used, the same as in Example 1 was used.
A flexible polyurethane foam having a density of 115.1 kg / m ³ was obtained.

[0022] The flexible polyurethane foams obtained in Examples and Comparative Examples were subjected to flammability evaluated according to the evaluation method of _{UL-94 (V 0 ~V 2} ). In the evaluation, (a) the amount of the molten dripping material during burning, (b) the easiness of carbonization, and (c) the fire spreadability were all visually evaluated. The results are shown in Table 1.

The evaluation criteria in Table 1 are as follows: the amount of the molten dripping material during burning ：: no dripping material, or even a very small amount of dripping material Δ: some dripping material X: many dripping materials Easiness of carbonization ○: easy to carbonize △: little carbonization ×: almost no carbonization fire spreadability ○: hard to spread ×: easy to spread

[0024]

[Table 1]

[0025]

As described above, the flexible polyurethane foam of the present invention comprises:
Compared with the conventional low-combustibility flexible polyurethane foam, it has less melted drops during combustion and is excellent in carbonization. Therefore, UL-94 which is a standard for electrical materials
(V ₀ -V ₂ ) Effective for passing the standard. In particular, when a polyurethane foam is combined with another material, for example, a fiber material, UL-94 (V ₀ ) can be passed.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 75/04 C08L 75/04 // (C08G 18/00 (C08G 18/00 101: 00) 101: 00 ) F-term (reference) 4J002 CC182 CK031 CK041 CP183 EB028 EB068 EG027 EN027 EN037 EN047 EU117 EU187 EW046 EZ047 FD132 FD136 FD157 FD328 4J034 BA03 DA01 DB03 DB07 DF01 DG01 DH00 DP18 HA01 HC71 K02 HC02 HC02 HC02 HC02 HC02 QA03 QB15 QB17 QC01 RA14

Claims (3)

[Claims] 1. A flexible polyurethane foam obtained by reacting a polyol component and a polyisocyanate component at least in the presence of additives including a foaming agent, a foam stabilizer, a catalyst and a flame retardant, wherein the polyisocyanate has an NCO index 1.8 ~
3.0 parts by weight of diphenylmethane diisocyanate (MDI), the flame retardant is 70 parts by weight or more of melamine resin and 30 to 70 parts by weight of an organic phosphorus flame retardant, 0.1 with respect to 100 parts by weight of the polyol component
２2.5 parts by weight of a dimethylpolysiloxane-polyoxyalkylene copolymer having a polyether terminal OH,
A low-flammability flexible polyurethane foam characterized by the following. 2. A catalyst comprising 0.1 to 2.0 parts by weight of potassium octylate, or 0.1 to 2.0 parts by weight of potassium octylate and 0.1 to 2.0 parts by weight, based on 100 parts by weight of a polyol component.
The low-combustibility flexible polyurethane foam according to claim 1, which is a combination system of 3.0 parts by weight of an amine catalyst. 3. The low-combustibility flexible polyurethane foam according to claim 1, wherein the foaming agent contains 0.1 to 2.0 parts by weight based on 100 parts by weight of the polyol component.