JP3332902B2 - Method for producing polyurethane foam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Flame retardancy, heat resistance,
The present invention relates to a method for obtaining a foam having a high foaming ratio and excellent low smoke generating properties.

[0002]

2. Description of the Related Art A urethane-modified polyisocyanurate foam has been known as a heat insulating material having excellent flame retardancy, heat resistance and low smoke generation. Regarding the flame retardancy, a mixture of a phosphonate and a phosphate has been reported as a composition for further improving the flame retardancy of a polyurethane or polyisocyanurate foam (JP-A-59-91116).
Further, phosphorus-halogen compounds as additives for flame-retardant urethane foams have the disadvantage of deteriorating the working environment due to odor or smoke. Therefore, as a flame-retardant additive, a phosphoric acid ester containing no halogen is used. Various types of phosphate esters have been reported (JP-A-61-278524).
As a result, the use of halogen-free materials as a flame retardant for rigid foams containing urethane and isocyanurate groups has resulted in concrete examples of aromatic phosphate esters of diphenylcresyl phosphate and tricresyl phosphate. (JP-A-4-226117). In cases where strict flame retardancy is not required for spray insulation work, there are cases where phosphate esters are used as a thickener for the same purpose as other phthalate esters and dibasic fatty acid esters ( JP-A-6-184340) reports that even in this case, phosphate esters were originally used as flame retardant additives. As another method of imparting flame retardancy, there is a way to seek the flame retardancy of the polyol component itself. In Japanese Patent Publication No. 7-30155, a modified phenol resin obtained by heating a polyhydric alcohol or an alkylene oxide adduct thereof in an amount of 20 to 100 parts by weight under reduced pressure to 100 parts by weight of a benzylic ether type phenol resin is used as a polyol. Heat resistance,
Polyurethane foam with low smoke emission and no surface brittleness is obtained.

[0003] On the other hand, the conversion of a specific CFC used as a blowing agent and an alternative CFC compound is indispensable, and a production method using water as a replacement for such a blowing agent is being studied. In the case of foaming with water (carbon dioxide), the foam tends to shrink at a high foaming ratio. To prevent this, a mixture of two or more surfactants having different surface tensions is used as a foaming agent, and foaming is performed. A method for improving the contraction by increasing the continuity of body cells has been reported (JP-A-11-286530). However, in this case, the flame retardancy did not satisfy a high standard. An example of a polyurethane foam satisfying a high level (for example, flame retardant second class) is reported in JP-A-11-343324. In this case, a special blended isocyanate compound or a reactive amine catalyst is used. Must be done.

[0004]

In the case of water foaming, which is an essential task for preserving the global environment, a large amount of urea bonds are incorporated into the polymer skeleton, which adversely affects the physical properties of the foam. At the time of foam production, since the isocyanate trimerization reaction, the carbon dioxide generation reaction by isocyanate and water, and the urethane reaction proceed in parallel,
There is the difficulty that optimal manufacturing conditions must be established while minimizing adverse effects on the physical properties of the foam. In particular, in order to obtain a polyurethane foam having excellent flame retardancy, heat resistance, and low smoke generation properties, technologies established before water foaming, for example, since most of the conventional technologies described above cannot be directly applied, water It is required to establish optimum combination conditions of a polyol component, a flame retardant, and the like under foaming.

[0005] The present invention uses water as a foaming agent, does not shrink even at a high foaming ratio, does not use an additive containing a halogen atom, and has a flame retardant (for example, flame retardant class 2). ),
An object of the present invention is to provide a method for producing a polyurethane foam having excellent characteristics of heat resistance and low smoke emission.

[0006]

Means for Solving the Problems The present inventors have used water as a foaming agent, have a high expansion ratio, do not shrink the foam, and have excellent characteristics of flame retardancy, heat resistance and low smoke generation. As a result of intensive studies on the production method of the polyurethane foam, particularly on the combination of the constituent components, the present invention has reached the present invention which satisfies the second grade of flame retardancy.

That is, the present invention relates to a polyisocyanate compound component (A) and a polyol component (B) wherein the polyol component is a polyhydric alcohol or an alkylene oxide adduct thereof of 20 to 100 parts by weight based on 100 parts by weight of a benzylic ether type phenol resin. Water (C) containing a modified phenol resin (hereinafter abbreviated as “BEP”) obtained by heating under reduced pressure in an amount of 3% by weight or more based on the total resin, water (C), A mixture of two or more types of silicone surfactants having a surface tension higher than 22 dyne / cm, and a surface tension lower than 22 dyne / cm. Reacting a foam stabilizer (T) having a tension and triethyl phosphate (E) in the presence of a urethanization catalyst or a trimerization catalyst (F). That is a method for producing a polyurethane foam.

In the present invention, a foam stabilizer comprising BEP as a polyol component, triethyl phosphate as a flame retardant, and a mixture of two or more silicone surfactants having different surface tensions is used. It has special features. That is, by combining BEP, triethyl phosphate, and a foam stabilizer comprising a mixture of two or more kinds of silicone surfactants having different surface tensions, the required performance is simultaneously exhibited, and water foaming is performed. This makes it possible to produce a polyurethane foam which does not shrink even at a high expansion ratio, and is particularly excellent in flame retardancy, heat resistance and low smoke generation.

As the phosphoric acid ester having no halogen atom, for example, there are 12 kinds of phosphoric acid esters exemplified in JP-A-61-278524. Among these, among the aromatic phosphate esters and the aliphatic phosphate esters, tributyl phosphate is insoluble in water, so that when water is used as a blowing agent as in the present invention, the compatibility in the resin is high. And the phosphoric acid esters cannot fully exhibit the performance originally possessed by these phosphate esters, which is not suitable. On the other hand, trimethyl phosphate itself has a strong hydrolyzability and is not suitable when used in the foam composition of the present invention because the long-term stability as a composition product deteriorates. The triethyl phosphate of the present invention has good compatibility with each component such as the BEP of the present invention and a silicone-based surfactant having a different surface tension, and sufficiently exhibits excellent flame retardancy. Therefore, the flame retardant class 2 has become possible.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The polyol component used in the present invention is a mixture of BEP and a polyol commonly used in the production of urethane foams. In other words,
No. 55, a modified method prepared by adding 20 to 100 parts by weight of a polyhydric alcohol or an alkylene oxide adduct thereof to 100 parts by weight of a benzylic ether type phenol resin and heating under reduced pressure. It is composed mainly of phenol resin (BEP). Other polyols that can be used together include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol,
Polypropylene glycol, polytetramethylene glycol, 1,4-butanediol, etc. or one or more alkylene oxides added thereto, and bifunctional polyol, trimethylolpropane, glycerin, etc., or alkylene oxide added thereto Polymerized trifunctional polyols, pentaerythritol, sorbitol, sugar, etc., or polyfunctional polyols obtained by addition-polymerizing an alkylene oxide thereto, and other products obtained by addition-polymerizing an alkylene oxide to an alkanolamine, and aromatic polyester polyols, acrylic It is a polyol resin, and these may be used alone or in combination of two or more. The amount of BEP used is suitably at least 3.0% by weight based on the total resin content. If the amount is less than 3.0% by weight, flame retardancy, heat resistance, and low smoke emission are deteriorated.

As the polyisocyanate compound used in the present invention, those generally used for producing urethane foams can be used, and are not particularly limited, and m- or p-phenylene diisocyanate, p- -Xylene diisocyanate, ethylene diisocyanate, tetramethylene-1,4-diisocyanate, hexamethylene-1,6-
Diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethyl-diphenylmethane-4,4'-
Diisocyanate, 3,3-dichloro-4,4'-biphenylene diisocyanate or 1,5-naphthalenediisocyanate, 2,4- and 2,6-tolylene diisocyanate and mixtures thereof, crude tolylene diisocyanate Nart, 4,4'-
Diphenylmethane diisocyanate, crude diphenylmethane diisocyanate and the like. These isocyanate compounds are used alone or in combination of two or more. The amount used is in the range of 1.05 to 5.0, preferably 1.50 to 3.0, equivalent ratio of the isocyanate group to the active hydrogen in the polyol component mixture. The equivalent ratio is 1.05
If it is smaller, flame retardancy, heat resistance, and low smoke emission will deteriorate,
If it is larger than 5.0, the brittleness of the foam increases, and the adhesiveness to the face material deteriorates.

The foam stabilizer used in the present invention is a mixture of two or more silicone surfactants having different surface tensions. The component having the higher surface tension has a surface tension of more than 22 dyne / cm. Is used. In general, an organic polysiloxane copolymer, a polydimethylsiloxane polyalkylene oxide adduct, and a vinylsilane / polyoxyalkylene polyol compound, which are generally used as a foam stabilizer during the production of urethane foam, are preferred. As the component having the lower surface tension, one having a surface tension of 22 dyne / cm or less is used, and dimethyl silicone oil is particularly preferable.

Examples of the organic polysiloxane copolymer include SH-190, SH-192, and S-190 manufactured by Toray Silicone Co., Ltd.
H-193, SH-194, M505, M507, M5
09, SRX253, manufactured by Nippon Unicar, L-5
20, L-540, L-580, L-582, L-53
40, L-5410, L-5420, L-5470, S
Z-1127, manufactured by Toshiba Silicone Co., Ltd., TFA-4
200, TFA4205, TFA7241, B-8404, B-8017 manufactured by Goldschmidt, and the like.

Examples of the dimethyl silicone oil include SH-200 manufactured by Toray Silicone Co., Ltd., TSF-451-5, TSF451-50, TSF manufactured by Toshiba Silicone Co., Ltd.
405 etc.

The mixing ratio of the component having the higher surface tension to the component having the lower surface tension is 100 parts by weight: 0.5 to 50 parts by weight.
A proportion by weight is appropriate. If the amount is less than 0.5 part by weight, no effect is observed and shrinkage occurs. On the other hand, when the amount is more than 50 parts by weight, the foam breaking effect becomes large, and a good foam cannot be obtained. The amount of the foaming agent, which is a mixture of two or more silicone surfactants having different surface tensions, is 0.5 to 10 with respect to 100 parts by weight of the polyol component (B).
Parts by weight are appropriate.

The triethyl phosphate used in the present invention is:
Usually, commercially available and used flame retardants can be used. The amount of triethyl phosphate used is not particularly limited, and can be changed according to the required properties of the foam. Preferred amounts are from 1 to 20% by weight, more preferably from 2 to 20% by weight, based on the weight of the total resin.
-10% by weight.

As the catalyst for performing the urethanization reaction, those generally known as urethanization catalysts can be used. For example, N, N, N ', N'-tetramethylethylenediamine, N, N, N', N'-tetramethylpropane
-1,3-diamine, N, N, N ', N'-tetramethylhexene-1,6-diamine, N, N, N', N ", N" -pentamethyldiethylenetriamine, N, N-dicyclohexylmethyl Amines, tertiary amines such as bis (N, N-dimethylaminoethylpiperazyl) ethane, N, N ', N "-tris (diethylaminopropyl) hexahydrotriazine, and dibutyltin dilaurate and dibutyltin diacetate; They can be used alone or in combination.

As the isocyanate trimerization catalyst used in the present invention, there can be used isocyanate trimerization catalysts conventionally used for producing polyisocyanurate resins and the like. Specific examples of the isocyanate trimerization catalyst include the following. In the organic metal salt system,
Potassium acetate, potassium octenoate, iron oxalate and the like. Tertiary amine salts include 2,4,6-tris (dimethylaminomethyl) -phenol, N, N ', N "-tris (dimethylaminopropyl) hexahydrotriazine and the like.

The amount of the urethanization catalyst and trimerization catalyst used in the present invention is 0.3 to 15 parts by weight, preferably 0.70 to 10 parts by weight, per 100 parts by weight of the polyol component (B). Parts by weight.

The water used in the present invention reacts with the polyisocyanate compound to generate carbon dioxide and act as a blowing agent. The amount of the water used is determined by the density of the target foam, and the amount of the polyol component (B) 100
A suitable amount is 2 to 30 parts by weight based on parts by weight. If the amount of water used is less than 2 parts by weight, the density of the foam becomes too high, and if it exceeds 30 parts by weight, the mechanical strength is reduced and the foam cannot be used.

In the present invention, a crosslinking agent and a viscosity reducing agent can be used as required. As a crosslinking agent, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, triethanolamine,
Ethylenediamine and the like can be used alone or in combination. As a thickener, nitrogen-containing, sulfur-containing, phosphorus-based, ether-based,
Room temperature liquid organic compounds such as hydrocarbons, esters, and carbonates can be used alone or in combination. These additives and other additives may be mixed in advance with the mixture containing the polyol component (B), or may be added during the reaction.

In the production method of the present invention, the mixing order of each component is as follows: polyol component (B), water (C), foam stabilizer (D), triethyl phosphate (E), urethanation catalyst and trimerization catalyst. A method in which a mixture of (F) is prepared in advance and mixed with the polyisocyanate compound (A) during the reaction, a polyol component (B), water (C), a foam stabilizer (D), and triethyl phosphate (E). Is prepared in advance and mixed with the polyisocyanate compound component (A) and the urethanization catalyst and trimerization catalyst (F) during the reaction, the polyol component (B), water (C), triethyl phosphate ( E) a method in which a mixture of a urethanization catalyst and a trimerization catalyst (F) is prepared in advance and mixed with the polyisocyanate compound component (A) and the foam stabilizer (D) during the reaction; A mixture of a polyol component (B), water (C), and triethyl phosphate (E) is prepared in advance, and a polyisocyanate compound component (A), a foam stabilizer (D), a urethanization catalyst and a trimerization catalyst are used during the reaction. A method of mixing with (F) can be adopted.

In the production of the polyurethane foam of the present invention, factory production or on-site foaming can be performed using a high-pressure foaming machine, a medium-pressure foaming machine, a low-pressure foaming machine, or the like.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. [%] Is based on weight. Density is J
Measured by ISA-9511. The production of the polyurethane foam was obtained by heating a 250 × 250 × 250 mm aluminum box to 40 ° C. and performing free foaming. In the flame retardancy test, a core part of the free-foamed foam was cut out, and a surface test was performed using a combustion tester of Toyo Seiki Seisaku-sho. (Specimen thickness 25 mm, heating time 10 minutes)

According to the formulation shown in Table 1 in Examples 1 to 6 and Comparative Examples 1 to 4, a liquid mixture (A) was prepared, and the isocyanate compound and a lab mixer were mixed and stirred at 4000 rpm. Later, a foam was produced using an aluminum box.

The raw materials used are as follows. BEP: Modified phenolic resin (Hodogaya Chemical Industry Co., Ltd.)
Polyamide 1: aromatic polyester polyol (PL-135, OH value 200, manufactured by Toho Rika Co., Ltd.) Other polyol 2: Glycerin-based polyether polyol (manufactured by Takeda Pharmaceutical Co., Ltd.) MF-78, OH value 35) TEP: Triethyl phosphate (manufactured by Bayer, flame retardant) TBP: Tributyl phosphate (manufactured by Bayer, flame retardant) TMCPP: Tris (monomethyl-2-chloropropyl) phosphate (Daichi Chemical ( Co., Ltd., flame retardant) Trimerization catalyst: potassium octenoate (PELRON C)
o. Foaming agent 1: Organic polysiloxane copolymer (manufactured by Toray Silicone Co., Ltd., SH-190, surface tension: 23.5 dyne / c)
m) Foaming agent 2: dimethyl silicone oil (TSF-451-100, manufactured by Toshiba Silicone Co., Ltd., surface tension: 20.8)
dyne / cm) Isocyanate compound: crude diphenylmethane diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., MR-10)
0, NCO content 31. 0
%)

The results are shown in [Table 1].

[0028]

【table 1】

From Table 1, it can be seen that the polyurethane foam of the present invention using water as a foaming agent and using a benzylic ether type phenol resin and triethyl phosphate has excellent flame retardancy.

[0030]

According to the polyurethane foam of the present invention,
Uses water as a foaming agent, does not shrink even at high foaming ratios, does not use additives containing halogen atoms, and is flame retardant (flame retardant class 2), heat resistant, low smoke A method for producing a polyurethane foam having the excellent characteristics described above can be provided.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08G 18/00-18/87

Claims (7)

(57) [Claims] 1. A polyisocyanate compound component (A),
A polyol component (B), the polyol component being a polyhydric alcohol or its alkylene oxide adduct 20 to 100 parts by weight of a benzylic ether type phenol resin;
Water (C), a silicone-based surfactant having a different surface tension, containing 100 parts by weight of the modified phenolic resin obtained by heating under reduced pressure, in an amount of 3% by weight or more based on the total resin content. Wherein the higher surface tension component has a surface tension greater than 22 dyne / cm, and the lower surface tension component has a surface tension of 22 dyne / cm.
A method for producing a polyurethane foam, comprising reacting a foam stabilizer (D) and triethyl phosphate (E) having the following surface tensions in the presence of a urethanization catalyst or a trimerization catalyst (F). 2. The component having a higher surface tension of the silicone surfactant is an organic polysiloxane copolymer having a surface tension of more than 22 dyne / cm, and the component having a lower surface tension is 22 dyne / cm. The method for producing a polyurethane foam according to claim 1, wherein the polyurethane foam is dimethyl silicone oil having a surface tension of not more than cm. 3. The mixing ratio of the foam stabilizer is 0.5 to 50 parts by weight of the component having the lower surface tension with respect to 100 parts by weight of the component having the higher surface tension. 0.5 to 100 parts by weight of the foam stabilizer in total
The method for producing a polyurethane foam according to claim 1 or 2, wherein 10 parts by weight are used. 4. A method according to claim 1, wherein said polyisocyanate compound component (A) is mixed with a polyol component (B) and water (C).
The equivalent ratio of the isocyanate group to active hydrogen is 1.05 to
5.0, and the water (C) is added to the polyol component (B) 100
4. The method for producing a polyurethane foam according to claim 1, wherein the polyurethane foam is used in an amount of 2 to 10 parts by weight based on parts by weight. 5. The use amount of triethyl phosphate (E) is 1 to 20% by weight based on the weight of the whole resin.
The method for producing a polyurethane foam according to any one of claims 1 to 4. 6. The method according to claim 1, wherein the urethanization catalyst or the trimerization catalyst (F) is used in an amount of 0.3 to 15 parts by weight based on 100 parts by weight of the polyol component (B).
A method for producing the polyurethane foam according to the above. 7. The method for producing a polyurethane foam according to claim 1, wherein a high-pressure foaming machine, a medium-pressure foaming machine, or a low-pressure foaming machine is used during the production of the polyurethane foam.