JP2644445B2 - Method for producing polyurethane foam - Google Patents

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 polyurethane foam, and more particularly, to a method for producing a polyurethane foam, which is suitable for continuous production of laminated boards, siding boards, sandwich panels, etc. The present invention relates to a method for producing a polyurethane foam having good adhesion.

[0002]

2. Description of the Related Art Conventionally, rigid polyurethane foams are often used as heat insulators for panels, boards, and the like because of their low thermal conductivity, low density, and easy handling. As a foaming agent used in the production of the foam, chlorofluorocarbon represented by Freon 11 has been used. In recent years, chlorofluorocarbon has destroyed the ozone layer in the stratosphere and has a bad effect on living systems. It turned out to be a possibility, and we needed to stop using it.

As an alternative foaming method, a method using a hydrogen-containing chlorofluorocarbon called an alternative fluorocarbon;
Although there is a method of utilizing carbon dioxide gas generated by the reaction between water and isocyanate, etc., alternative fluorocarbons will be regulated in the future. On the other hand, foaming due to the reaction between water and isocyanate has several problems, one of which is that the urea bond generated with the generation of carbon dioxide gas reduces the adhesiveness of the form.

Several reports have been made in the past on improving the adhesiveness of polyurethane foams in conventional formulations, for example, a method using a special polyol (Japanese Patent Laid-Open Publication No.
JP-A-119915, JP-A-60-69118, JP-A-60-166315, etc.); a method of using a benzylic ether type phenol resin or a combination with a high molecular weight polyoxyethylene propylene polyol ( JP-A-58-208317, JP-A-63-2113512, etc.); a method of using an aromatic isocyanate and an aliphatic isocyanate in combination (see JP-A-59-161423); and adding ethylene glycols Method (see Japanese Patent Application Laid-Open No. 60-133304); Method of adding a halogen-containing phosphoric ester (see Japanese Patent Application Laid-Open No. 60-76540); Method of combining a specific catalyst (see Japanese Patent Application Laid-Open No. 2-142816). A method for prepolymerizing an isocyanate component (JP-A-Hei 3
-195717). However, none of these proposed methods has always been satisfactory in bonding polyurethane foams and surface materials which do not use an evaporating foaming agent such as Freon.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on polyurethane foams which do not use an evaporative foaming agent such as chlorofluorocarbon to increase the adhesion to the surface material.
This time, it has been found that a polyurethane foam having a high adhesive strength can be obtained by reacting an organic polyisocyanate with a polyol and water in the presence of an aliphatic phosphate ester having a molecular weight of 140 to 270 and containing no halogen. Was.

[0006] Thus, according to the present invention, an organic polyisocyanate can be prepared by converting a halogen-free molecular weight of 140-2.
There is provided a process for producing a polyurethane foam, comprising reacting a polyol and water in the presence of an aliphatic phosphate ester of No. 70.

Hereinafter, the present invention will be described in more detail.

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. Polyurethane and those used in the production of polyurethane can also be used. Specifically, for example, aromatic diisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, crude tolylene diisocyanate, methylene diphenyl diisocyanate, and crude methylene diphenyl diisocyanate; Aromatic triisocyanates such as phenylmethane triisocyanate, 2,4,6-tolylene triisocyanate; 4,4'-
Aromatic tetraisocyanates such as dimethyldiphenylmethane-2,2'-5,5'-tetraisocyanate; aliphatic isocyanates such as hexamethylene-1,6-diisocyanate; alicyclic isocyanates such as hydrogenated methylenediphenyldiisocyanate; m-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. Among them, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, crude tolylene diisocyanate, methylene diphenyl diisocyanate, crude methylene diphenyl diisocyanate, hexa Methylene-1,6-diisocyanate, hydrogenated methylene diphenyl diisocyanate and the like are preferred. The above organic polyisocyanates can be used alone or in combination of two or more.

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

The above polyols are generally used in an amount of from 20 to 60.
0 mgKOH / g, preferably 25-500 mgKOH
/ G, more preferably in the range of 50 to 400 mg KOH / g.

According to the method of the present invention, a polyurethane foam is produced by reacting the above-mentioned organic polyisocyanate with a polyol together with water as a foaming agent. In this reaction, the proportions of the organic polyisocyanate, polyol and water are not strictly limited, and can be varied over a wide range depending on the physical properties and applications desired for the polyurethane foam of the final product. Has an isocyanate index represented by an NCO / OH equivalent ratio of 0.8 to 1.2, preferably 0.9 to 1.2.
It is preferable to mix and react the above components so as to be within a range of 1.1, particularly 0.95 to 1.05.

[0012] The amount of water used as a foaming agent can be adjusted depending on the density and the like desired for the polyurethane foam of the final product. In particular, the method of the present invention has a great feature in that a product having high adhesive strength can be produced even by foaming only with water without using an evaporative foaming agent such as chlorofluorocarbon. , Organic polyisocyanate, polyol and water based on the total weight of water.
3-3 wt%, preferably Blend the water in an amount ranging from 0.8 to 2.5 wt%, without the use of volatile blowing agents, free foaming density generally 50 kg / ^{m 3} or less, Especially 20-35
Even when a foam having a high expansion ratio of kg / m ³ is manufactured, high adhesive strength can be obtained.

A feature of the method of the present invention is that the reaction for producing a polyurethane foam from the above-mentioned organic polyisocyanate, polyol and water is carried out in the presence of a halogen-free aliphatic phosphate having a molecular weight of 140 to 270. The point is to implement.

The above-mentioned halogen-free aliphatic phosphate esters can be known per se, and are usually, for example, 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, methyl diethyl phosphate, methyl dibutyl phosphate, and ethyl dibutyl phosphate. Among them, trimethyl phosphate, triethyl phosphate, and tributyl phosphate are particularly preferably used. These phosphate esters can be used alone or in combination of two or more.

In the present invention, the halogen-free aliphatic phosphate may be previously mixed with an organic polyisocyanate, may be mixed with a polyol component, or may be added during the reaction. The effect on the adhesion is greater when preliminarily mixed with.
Although the reason is not clear, it is assumed 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 can be freely changed according to the required properties of the product and the like. Generally, it is preferable to use it in the range of 1 to 20% by weight, particularly 3 to 10% by weight.

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

As a method for producing a polyurethane foam from each of the above-mentioned components, for example, an isocyanate component comprising the above-mentioned organic polyisocyanate or an isocyanate prepolymer component obtained by previously reacting an organic polyisocyanate with a polyol is used. The above-mentioned polyol, water, and a polyol component to which a urethane-forming catalyst, a foam stabilizer, a cross-linking agent, a flame retardant, a coloring agent and other additives are further added, if necessary, are prepared, and an isocyanate component or a polyol component or both components are prepared. , A predetermined amount of a halogen-free aliphatic phosphoric acid ester is added to the mixture, the two components are put together at the time of use, and the mixture is rapidly stirred and mixed, followed by foaming and curing.

The reaction temperature is usually sufficient at room temperature, but in some cases the temperature may be raised to about 90 ° C.

Hereinafter, the present invention will be described more specifically with reference to examples.

[0021]

【Example】

Examples 1 to 16 and Comparative Examples 1 to 13 A predetermined amount of polyol shown in Tables 1 and 2 below,
A total of 100 g of a polyol component prepared by mixing water, a catalyst, a foam stabilizer, and a flame retardant, and a crude MDI (diphenylmethane diisocyanate) component (Examples 9 to 10)
11 and Comparative Example 10 were mixed to give 200 g), and a hand drill (2200 rpm, stirring blade 30 mm) was used.
(φ) for 4 seconds. 80 g of the mixture (Example 9)
~ 11 and Comparative Example 10 are 150 g) 150 x 150 x 1
The mixture was poured into a 50 mm wooden box, and the cream time, gel time, and rise time were measured. The time from the liquid to the start of foaming was defined as cream time, the time during which the inside was hardened (the time when the stick did not touch) was defined as gel time, and the time at which foaming was completed was defined as rise time. Further, the center of the cured foam was cut into about 100 × 100 × 100 mm, and the free foam density was calculated from the volume and weight.

On the other hand, the adhesive strength to paper was 60 ° C.
Kraft paper (kraft 70g: manufactured by Nippon Matai) was set inside a 300 × 300 × 15 mm mold heated to 50 g, and 50 g (Examples 9-1)
For 1 and Comparative Example 10, 70 g) were injected, and the samples were molded. The sample was demolded 1 minute after injection, and 4 minutes later,
A 10 cm wide cut is made and the kraft paper is peeled off with a spring scale. The value of the spring scale at that time is taken as the adhesive strength and expressed in kg / 10 cm.

The adhesive strength between the iron plate and the aluminum plate was also set inside the mold in the same manner as for paper to form a sample. The sample was removed from the mold 1 minute after the injection, left to stand for 24 hours, cut into 50 × 50 × 15 mm,
The strength was measured by a method based on IS K-6848.

The product of Example 5 is further described in JIS
A physical property test based on A-9514 was performed.

The results are shown in Tables 1 to 5 below.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

[Table 3]

[0029]

[Table 4]

Note (1): Polyol Polyol A: Polyether-based polyol, hydroxyl value =
230 (NFS-24 manufactured by Takeda Pharmaceutical Co., Ltd.) Polyol B: polyether-based polyol, hydroxyl value =
410 (RX-403 manufactured by Sanyo Chemical Industries, Ltd.) Polyol C: polyether-based polyol, hydroxyl value =
460 (manufactured by Asahi Glass Co., Ltd., FD-590) Note (2): Catalyst DABCO 33LV: Triethylenediamine (active ingredient 33%) KAO No. 1: N, N, N ', N',-tetramethylhexamethylenediamine (active ingredient 98%) Note (3): Foam stabilizer dimethylsiloxane-polyether block copolymer (Toray Dow Corning, CF-2050) 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

[0031]

[Table 5]

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication location C08G 101: 00) C08L 75:04 (56) References JP-A-50-86598 (JP, A) JP-A-61-31421 (JP, A) JP-A-6-116353 (JP, A) JP-A-49-20156 (JP, A) JP-B-45-41219 (JP, B1) "Polyurethane resin" by Keiji Iwata Handbook (1st edition) "(S62.9.95) Published by Nikkan Kogyo Shimbun 93, 98, 300

Claims (5)

(57) [Claims] 1. The method of claim 1, wherein the organic polyisocyanate is trimethyl
Phosphate, triethyl phosphate and tributyl
At least one trialkyl selected from phosphates
A method for producing a polyurethane foam without using an evaporating foaming agent, comprising reacting an organic polyol and water in the presence of luphosphate. 2. The method according to claim 1, wherein the trialkyl phosphate and the organic polyisocyanate are mixed, and the mixture is reacted with an organic polyol and water. 3. The compounding ratio of the organic polyisocyanate, the organic polyol and water is in the range of 0.8 to 1.2 in the isocyanate index represented by the NCO / OH equivalent ratio. The method of claim 1. 4. An organic polyol comprising 20 to 600 mg KO.
The method according to claim 1, which is at least one polyol having a hydroxyl value in the range of H / g. 5. Water is present in an amount of 0.3 to 3% by weight, based on the total weight of the organic polyisocyanate, organic polyol and water.
2. The method according to claim 1, wherein the amount is used.