JPH0782334A - Production of polyisocyanurate foam - Google Patents

Abstract

PURPOSE:To obtain a polyisocyanurate foam which has good adhesion to paper or the like even when it has a high expansion ratio without using any volatile blowing agent such as a chlorofluorocarbon. CONSTITUTION:An organic polyisocyanate is reacted with a polyol and water in the presence of a halogen-free aliphatic phosphoric ester and a trimerization catalyst to obtain a polyisocyanurate foam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyisocyanurate foam, and more particularly to a polyisocyanurate foam suitable for continuous production of laminate boards, siding boards, etc., which has particularly good adhesion to paper. A method of manufacturing a body.

[0002]

2. Description of the Related Art Conventionally, hard urethane foams and isocyanurate foams are often used as heat insulating materials in panels, boards, etc. because of their low thermal conductivity, low density, and easy handling. It is used. Chlorofluorocarbon typified by Freon 11 has been used as a foaming agent used in the production of the foam, but in recent years, chlorofluorocarbon destroys the ozone layer in the stratosphere and adversely affects biological systems. It turned out to be possible, and I had to stop using it.

As the alternative foaming method, a method using hydrogen-containing chlorofluorocarbon called alternative CFC,
Although there is a method of using carbon dioxide gas generated by the reaction of water and isocyanate, alternative CFCs are likely to be regulated in the future. On the other hand, there are some problems in foaming due to the reaction between water and isocyanate, and one of them is that the urea bond formed with the generation of carbon dioxide reduces the adhesiveness of the foam. Especially in the case of isocyanurate foam, the decrease is remarkable.

Several reports have been made in the past regarding the improvement of the adhesiveness of urethane foams or isocyanurate foams in conventional formulations. For example, a method using a special polyol (Japanese Patent Application Laid-Open No. 57-119915, JP JP-A-60-69118 and JP-A-60-166315.
JP-A-58-2) or the like); a method of using a benzylic ether type phenol resin or a method of using it together with a high molecular weight polyoxyethylene propylene polyol (JP-A-58-2).
No. 08317, JP-A-63-213512, etc.); A method in which an aromatic isocyanate and an aliphatic isocyanate are used in combination (see JP-A-59-161423); A method in which ethylene glycols are added (JP-A-SHO) 6
0-1333034); method of adding halogen-containing phosphate ester (see JP-A-60-76540); combination of specific catalysts (JP-A-2-14)
2816); a method of prepolymerizing an isocyanate component (see JP-A-3-195717) and the like. However, none of these proposed methods is satisfactory in the adhesion between a polyisocyanurate foam which does not use an evaporative foaming agent such as CFC and a face material (particularly paper).

[0005]

[Means for Solving the Problems] As a result of intensive investigations by the present inventors, in order to improve the adhesive strength with a face material (particularly paper) in a polyisocyanurate foam which does not use an evaporative foaming agent such as CFC, this time, By reacting an organic polyisocyanate with a polyol and water in the presence of a halogen-free aliphatic phosphate having a molecular weight of 140 to 270 and a trimerization catalyst, a polyisocyanurate foam having high adhesive strength is obtained. I found what I could get.

Thus, according to the present invention, the organic polyisocyanate has a halogen-free molecular weight of 140 to 2
There is provided a process for making a polyisocyanurate foam characterized by reacting with a polyol and water in the presence of 70 aliphatic phosphate esters and a trimerization catalyst.

The present invention will be described in more detail below.

The organic polyisocyanate used as a raw material in the method of the present invention may be of any type such as an aliphatic type, an alicyclic type, an aromatic type and a mixed type thereof. Those used in the production of polyurethane and polyisocyanurate can be similarly used. Specifically, for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate,
Aromatic diisocyanates such as crude tolylene diisocyanate, methylene diphenyl diisocyanate and crude methylene diphenyl diisocyanate; Aromatic triisocyanates such as 4,4 ', 4 "-triphenylmethane triisocyanate; 2,4,6-Tolylene triisocyanate;
4,4'-Dimethyldiphenylmethane-2,2'-5,5'-
Aromatic tetraisocyanates such as tetraisocyanates; Aliphatic isocyanates such as hexamethylene-1,6-diisocyanate; Alicyclic isocyanates such as hydrogenated methylenediphenyldiisocyanate;
-Phenylene diisocyanate, naphthylene-1,5-diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, 4,4'-biphenylene diisocyanate, 3,
3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate and the like can be mentioned. Among them, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, Crude tolylene diisocyanate, methylene diphenyl diisocyanate, crude methylene diphenyl diisocyanate,
Hexamethylene-1,6-diisocyanate, hydrogenated methylenediphenyldiisocyanate and the like are preferable. The above organic polyisocyanates may be used alone or in combination of two or more.

As the polyol, compounds such as polyether polyol, polyester polyol, castor oil, etc., such as aliphatic series, sugar series, aromatic series and mixtures thereof having two or more hydroxyl groups in one molecule. And those conventionally used in the production of polyurethanes can be used as well. Such a polyol may have either a low molecular weight or a high molecular weight, and specifically, for example, as the polyether polyol, an alkylene is added to an active hydrogen-containing compound such as polyhydric alcohol, polyhydric phenol, amines and polycarboxylic acid. An example is a compound having a structure to which oxide is added. As polyhydric alcohol,
For example, ethylene glycol, propylene glycol,
Dihydric alcohols such as 1,4-butanediol, 1,6-hexanediol, diethylene glycol and neopentyl glycol; 3 such as pentaerythritol and sucrose
Examples include polyhydric alcohols having a valency or more. Examples of polyhydric phenols include polyhydric phenols such as pyrogallol and hydroquinone, bisphenols such as bisphenol A, and condensation products of phenol and formaldehyde. Amines include ammonia, mono-, di-
-, And alkanolamines such as triethanolamine, isopropanolamine, aminoethylethanolamine; C ₁ -C ₂₂ alkylamines, C ₂ -C ₆
Aromatic amines such as alkylenediamine, polyalkylenepolyamine and aniline, phenylenediamine, diaminotoluene, xylylenediamine, methylenedianiline, diphenyletherdiamine, alicyclic amines such as isophoronediaminecyclohexylenediamine, heterocyclic amines Kind and the like. As the polycarboxylic acid, aliphatic polycarboxylic acids such as succinic acid, adipic acid, sebacic acid, maleic acid and dimer acid, aromatic polycarboxylic acids such as phthalic acid, terephthalic acid, trimellitic acid and pyromellitic acid, etc. Two or more of these active hydrogen-containing compounds can be used.
Examples of the alkylene oxide added to the active hydrogen-containing compound include propylene oxide, ethylene oxide, butylene oxide, and tetrahydrofuran. These alkylene oxides may be used alone or in combination of two or more, and in the latter case, they may be block-added or random-added.
Examples of polyester polyols include polyhydric alcohols (the above dihydric alcohols, trimethylolpropane, glycerin, etc.) and carboxylic acids (the above polycarboxylic acids, etc.)
A condensed polyester polyol obtained by reacting with
Examples thereof include polyester polyols obtained by ring-opening polymerization of lactones, and recovered polyesters to which an ethylene oxyd adduct of nonylphenol is added. Among these, in particular, aliphatic, aromatic, aliphatic or aromatic amine, pentaerythritol, sucrose polyether polyols; aromatic or aliphatic carboxylic acid polyester polyols; lactone polyester polyols and the like are preferable. Is. The above polyols can be used alone or in combination of two or more kinds.

Polyols such as those mentioned above are generally 20-60.
0 mgKOH / g, preferably 25-500 mgKOH
/ G, more preferably 50 to 400 mg KOH / g.

According to the method of the present invention, a polyisocyanurate foam is produced by reacting the above-mentioned organic polyisocyanate and polyol with water as a foaming agent. In this reaction, the use ratios of the organic polyisocyanate, the polyol and the water are not strictly limited, and can be varied over a wide range according to the desired physical properties and intended use of the polyisocyanurate foam of the final product. Generally, it is preferable to mix and react the above components so that the isocyanate index represented by the NCO / OH equivalent ratio is 1.8 or more, preferably 1.8 to 5, and particularly 2 to 4. Is.

The amount of water used as a foaming agent can be adjusted according to the desired density of the polyisocyanurate foam of the final product. In particular, the method of the invention comprises
There is a great feature in that it is possible to produce a product having a high adhesive force even by foaming only water which does not use an evaporative foaming agent such as CFC, and according to the method of the present invention, for example, an organic polyisocyanate, a polyol and water are used. 0.3 to 3% by weight, preferably 0.8 to 2.5% by weight, based on the total weight
Dispense water in the range of, without using evaporative blowing agent,
Free foam density is generally 50 kg / m ³ or less, especially 20 to
Even if a foam having a high expansion ratio of 35 kg / m ³ is produced, high adhesive strength can be obtained. A feature of the method of the present invention is that the reaction for producing a polyisocyanurate foam from the above-mentioned organic polyisocyanate, polyol and water is carried out by trimerization of halogen-free aliphatic phosphate ester having a molecular weight of 140 to 270 and isocyanate. The point is to carry out in the presence of a catalyst.

The above-mentioned halogen-free aliphatic phosphoric acid ester can be known per se, for example, usually, dyes, defoamers for detergents, metal extractants, catalysts for polyester resins and epoxy resins. Commercially available diluents and rubber additives can be used. Specific examples include trialkyl phosphates such as trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, methyldiethyl phosphate, methyldibutylphosphate, ethyldibutylphosphate and the like. Among these, trimethyl phosphate, triethyl phosphate and tributyl phosphate are particularly preferably used. These phosphoric acid esters can be used alone or in combination of two or more kinds.

In the present invention, the halogen-free aliphatic phosphate ester may be mixed in advance with the organic polyisocyanate, may be mixed with the polyol component, or may be added at the time of reaction. The effect on adhesion is greater if the mixture is premixed with and the mixture is reacted with the polyol and water in the presence of the trimerization catalyst. The reason for this is not clear, but it is presumed that the compatibility between the isocyanate component and the polyol component contributes.

The amount of the halogen-free aliphatic phosphate ester used is not strictly limited and may be freely changed according to the required properties of the product, but based on the weight of the entire reaction system. Generally, it is preferable to use it in the range of 1 to 20% by weight, particularly 3 to 10% by weight.

The isocyanate trimerization catalyst used in combination with the halogen-free aliphatic phosphate ester is not particularly limited, and it has been conventionally used for producing polyurethane, polyisocyanurate, polyurethane-polyisocyanurate resin and the like. The isocyanate trimerization catalysts known per se used in the process can likewise be used, examples of which include:

[0017]

[Chemical 1]

[0018]

[Chemical 2]

Among these trimerization catalysts, the above (1),
The compounds of (3), (4), (7) and (9) are preferably used.

The amount of the above-mentioned trimerization catalyst to be used is also not strictly limited, but based on the weight of the entire reaction system,
Generally, a range of 0.2 to 5% by weight, preferably 0.4 to 3% by weight is suitable.

Further, in the method of the present invention, if necessary, a urethanization catalyst (eg, triethylenediamine, dimethylethanolamine, triethylamine, trimethylaminoethylethanolamine, dimethylaminoethyl ether, pentamethyldiethylenetriamine, N-methyl) is used. Morpholine, dibutyltin dilaurate,
Tin octoate, lead octoate, etc.), foam stabilizer (eg,
Dimethylsiloxane-polyether block copolymer, etc.), cross-linking agent (for example, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethanolamine, diethanolamine, ethylenediamine, toluenediamine, etc.), Flame retardants (eg triphenyl phosphate, cresyl diphenyl phosphate, tris cresyl phosphate, tris chloroethyl phosphate, tris dichloropropyl phosphate, tris-β-chloropropyl phosphate, tris-β-chloroethyl phosphate. Fate, tris (2,3-dibromopropyl) phosphate, tris (bromocresyl) phosphate, melamine, antimony trioxide, etc.), colorants, and other additives It can be used in combination in amounts that are normally used.

As a method for producing a modified polyisocyanurate foam from the above components, for example, an isocyanate component composed of the above-mentioned organic polyisocyanate or an isocyanate prepolymer obtained by previously reacting an organic polyisocyanate with a polyol is used. Ingredients, the above-mentioned polyol, water, trimerization catalyst, and further, a urethane component, a foam stabilizer, a cross-linking agent, a flame retardant, a colorant and other polyol components are added to the polyol component if necessary, and isocyanate is prepared. A method may be mentioned in which a predetermined amount of a halogen-free aliphatic phosphate ester is added to the component or the polyol component or both components, both components are combined at the time of use, the mixture is rapidly stirred and mixed, and then foamed and cured.

The reaction temperature is usually room temperature, but in some cases, it may be heated to a temperature of up to about 90 ° C.

The present invention will be described in more detail with reference to the following examples.

[0025]

【Example】

Examples 1 to 15 and Comparative Examples 1 to 14 Polyol component prepared by mixing predetermined amount of polyol, water, catalyst, foam stabilizer and phosphoric ester shown in Table 1 below, and crude MDI (diphenylmethane diisocyanate) And the isocyanate component prepared by mixing the phosphoric acid ester with 100 g in total (Example 1
2 to 14 were mixed so as to be 200 g), and stirred with a hand drill (2200 rpm, stirring blade 30 mmφ) for 4 seconds. 80 g of the mixture (15 for Examples 12-14)
0 g) It was poured into a wooden box of 150 × 150 × 150 mm and the cream time, gel time and rise time were measured. The time from the liquid state to the start of foaming is called the cream time, and the time when the inside hardens (the time when the stick does not touch)
Was taken as the gel time, and the time when foaming was completed was taken as the rise time. About 100x the center of the cured foam
It was cut into 100 × 100 mm, and the free foam density was calculated from its volume and weight.

On the other hand, regarding the adhesive strength, aluminum kraft paper (Craft 70 g: made by Nippon Matai) was set inside the 300 × 300 × 15 mm mold heated to 60 ° C.,
50 g (55 in Example 11) in the same manner as the free foam.
g, 12 to 14 were 70 g), and a sample was molded. The sample was demolded 1 minute after injection and 4 minutes later, 1
A notch having a width of 0 cm is made, the kraft paper is peeled off by the spring weigher, and the value of the spring weigher at that time is taken as the adhesive strength and expressed in kg / 10 cm.

For the product of Example 5, further JIS
Physical property test based on A-9514 and JIS A-13
A flammability test based on No. 21 was carried out.

The results are shown in Tables 1 to 3 below.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

[Table 4]

Note (1): Polyol Polyol A: Phthalate ester type polyol, hydroxyl value = 145 (PL-106 manufactured by Toho Rika Kogyo Co., Ltd.) Polyol B: Pentaerythritol type polyol, hydroxyl value = 410 (410NE manufactured by Asahi Glass Co., Ltd.) Polyol C: Syuger aromatic amine-based polyol, hydroxyl value = 410 (manufactured by Sanyo Kasei Co., RX-403)

[0034]

[Chemical 3]

Note (3): Foam stabilizer dimethylsiloxane-polyether block copolymer (SF-2936F manufactured by Toray Dow Corning Co., Ltd.) Note (4): Phosphate ester TMP: Trimethyl phosphate TEP: Triethyl phosphate TBP: Tributyl phosphate TOP : Trioctyl phosphate CLP: Tris / chloroethyl phosphate TCP: Tris / cresyl phosphate TMCPP: Tris / β-chloropropyl phosphate ODPP: Octyl diphenyl phosphate CR-530: Halogen-containing condensed phosphate ester (manufactured by Daihachi Chemical Co., Ltd.) CR -505: Halogen-containing condensed phosphate ester (manufactured by Daihachi Chemical Co., Ltd.)

[0036]

[Table 5]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area // (C08G 18/32 101: 00) C08L 75:04

Claims (6)

[Claims] 1. A polyisocyanurate foam comprising reacting an organic polyisocyanate with a polyol and water in the presence of a halogen-free aliphatic phosphate having a molecular weight of 140 to 270, and a trimerization catalyst. Manufacturing method. 2. The method according to claim 1, wherein the aliphatic phosphate ester is at least one trialkyl phosphate selected from trimethyl phosphate, triethyl phosphate and tributyl phosphate. 3. A process according to claim 1, wherein the aliphatic phosphate ester and the organic polyisocyanate are mixed and the mixture is reacted with a polyol and water in the presence of a trimerization catalyst. 4. The method according to claim 1, wherein the organic polyisocyanate is reacted with the polyol and water at an isocyanate index represented by an NCO / OH equivalent ratio of 1.8 or more. 5. The polyol is 20 to 600 mg KOH /
The method according to claim 1, which is at least one polyol having a hydroxyl value within the range of g. 6. A process according to claim 1, wherein water is used in an amount of 0.3 to 3% by weight, based on the total weight of organic polyisocyanate, polyol and water.