JPH0215572B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a uniform foam from a polyisocyanate compound with excellent water dispersibility and a plastic emulsion.

A method of obtaining a foam by simply mixing water with an isocyanate group-containing prepolymer made of a hydrophilic polyol and a polyisocyanate compound is well known. This method is suitable for producing ordinary soft foams, but in order to foam in combination with two-component spray foaming or plastic emulsion, polyisocyanates must be well dispersed in the water medium. Therefore, the above-mentioned isocyanate group-containing prepolymers were unsuitable.

Additionally, polyisocyanate compounds have RO
(CH ₂ CH ₂ O)nH or R′ (OCH ₂ CH ₂ )
obtained by reacting a polyethylene oxide derivative represented by mOOCCH ₂ COO(CH ₂ CH ₂ O)nR' (where R and R' are alkyl groups having 1 to 4 carbon atoms, and n and m are 5 to 120 on average). The self-emulsifying polyisocyanate is known (Japanese Patent Publication No. 7472/1983).
However, the purpose of this polyisocyanate is to create a stable emulsion by dispersing it with water, and its dispersion performance is insufficient to obtain a foam when combined with the plastic emulsion of the present invention, making it undesirable. That is, in the technique described in the above-mentioned publication, polyisocyanate is dispersed with water to form an oil-in-water emulsion to form stable capsules. Therefore, the pot life of this emulsion is relatively long, usually 3 to 5 hours at 25°C. When used, it is necessary to heat the isocyanate in order to utilize it effectively and quickly. In this known invention, an isocyanate-terminated prepolymer obtained by reacting an excess diisocyanate or a highly functional polyisocyanate with a hydroxyl-terminated polyether may be used as the polyisocyanate, but the above-mentioned oil-in-water emulsion is formed. In order to
(CH ₂ CH ₂ O)nH or R′ (OCH ₂ CH ₂ )
The polyethylene oxide derivative portion of mOOCCH ₂ COO(CH ₂ CH ₂ O)nR′ acts as a hydrophilic group, and the isocyanate portion needs to act as a lipophilic group. As the polyether, lipophilic ones such as oxypropylated glycerol are used.

On the other hand, in order to obtain a foam in combination with a plastic emulsion, a polyisocyanate compound with excellent water dispersibility is required, and an oil-in-water emulsion, which is stable when dispersed with water, is not suitable. It means that there is. The type dispersed with water is basically preferably an oil-in-water type, but it is preferable that it is not a clear oil-in-water type but is partially water-soluble. This is because, in a stable oil-in-water emulsion, carbon dioxide gas generation due to the reaction between water and isocyanate is extremely slow and no foam is formed.

In view of the above viewpoint, the present inventors conducted various research on polyisocyanate compounds with excellent water dispersibility that can be combined with plastic emulsions to obtain uniform foams, and as a result, a polyisocyanate compound obtained as follows It has been found that the compound is suitable.

That is, (A) 100 parts by weight of diphenylmethane diisocyanate-based polyisocyanate, (B) RO(CH ₂ CH ₂ O)nH or R′(OCH ₂ CH ₂ )
mOOCCH ₂ COO(CH ₂ CH ₂ O) nR′(R and
R' is the same or different alkyl group having 1 to 4 carbon atoms, n and m are 5 to 120 on average) 1 to 20 parts by weight of a polyethylene oxide derivative;
and (C) ethylene oxide/propylene oxide in a molar ratio of 1/0 to 1/3 with a molecular weight of 200 to
6000 polyether diols and/or polyether triols in an NCO/OH molar ratio of 2
It is a polyisocyanate compound obtained by reacting at a ratio of ~20%.

Diphenylmethane diisocyanate-based polyisocyanates used in the present invention include diphenylmethane diisocyanate (hereinafter referred to as MDI), liquefied MDI obtained by partially modifying with carbodiimide, and polyphenylmethane polysaccharide called polymeric MDI. In addition to isocyanates, reaction products of these polyisocyanates and active hydrogen-containing compounds, or mixtures thereof, mixtures of the above compounds with other isocyanate compounds such as tolylene diisocyanate, naphthylene diisocyanate, and hexamethylene diisocyanate. Alternatively, modified products can also be used.

As mentioned above, the polyethylene oxide derivative (B) used in the present invention has the general formula RO(CH ₂ CH ₂ O)nH (1) or R′(OCH ₂ CH ₂ )mOOCCH ₂ COO(CH ₂ CH ₂ O).
It is represented by nR' (2), where R, R', n, and m are as defined above, and R and R' are particularly preferably methyl groups.

The amount of polyethylene oxide derivative (B) to be reacted with 100 parts by weight of polyisocyanate (A) is (1)
Or, depending on the number of n and m in the formula (2),
As mentioned above, the amount is preferably from 1 to 20 parts by weight; if it is less than 1 part by weight, the water dispersibility will be poor, and if it is more than 20 parts by weight, the water dispersibility will not be improved commensurate with the amount added, which is economically disadvantageous.

The polyether diol or polyether triol (C) used in the present invention uses water, diols such as ethylene glycol, butylene glycol, etc., or glycerin, trimethylolpropane, triethanolamine, etc. as a starting material. By block polymerizing triols with ethylene oxide/propylene oxide at a molar ratio of 1/0 to 1/3, the molecular weight is 200 to 200.
6000. The amount of the polyether relative to the polyisocyanate varies depending on the composition of the polyether, but the NCO/OH molar ratio is preferably in the range of 2 to 20. If the NCO/OH molar ratio is less than 2, the polyisocyanate compound after the reaction becomes highly viscous and is not stable in storage. If it is more than 20, the water dispersibility will be poor, so it is not suitable.

The reaction of (A) polyisocyanate, (B) polyethylene oxide derivative and (C) polyether in the present invention is carried out under normal urethanization conditions. For example, the reaction temperature is suitably in the range of 20 to 120°C, and these are uniformly mixed and reacted. The polyethylene oxide derivative and polyether to be reacted with the polyisocyanate can be added at the same time, but it is also possible to add the polyisocyanate and the polyethylene oxide derivative reacted in advance after the polyether and the polyisocyanate have reacted. Further, a mixture of two or more types of each of the polyethylene oxide derivative and the polyether may be used.

The polyisocyanate compound obtained as described above contains stabilizers, flame retardants, foam stabilizers, surfactants, viscosity modifiers, and
Plasticizers, solvents, wax release agents such as vegetable waxes, mineral waxes, etc. can be added to produce foams by spray application or in combination with plastic emulsions. For spray application, it is effective to add stabilizers such as dibutyl phthalate.

The polyisocyanate compound obtained by the method of the present invention is not a stable oil-in-water type and reacts quickly with water, so when combined with a plastic emulsion, it quickly generates CO ₂ and produces a uniform foam. The foam has a wide range of uses, including civil engineering and construction materials such as waterproofing materials, heat insulation materials, vibration-proofing materials, and soundproofing materials, and industrial materials such as adhesives, laminating agents, paints, molding materials, and various packing materials. It can be used effectively.

Plastic emulsions used in the production of foam include acrylonitrile/butadiene latex, acrylate latex, styrene/butadiene latex, vinyl chloride latex, vinyl chloride/vinyl acetate latex,
These include acrylonitrile/vinyl acetate latex, natural rubber latex, etc. To these plastic emulsions, relatively low molecular weight active hydrogen-containing compounds such as ethylene glycol, glycerin, trimethylolpropane, and triethanolamine, or water-soluble or water-dispersible polyols such as polyethylene glycol, polyvinyl alcohol, and modified cellulose are added. Can be added.

In producing the foam, the polyisocyanate compound obtained by the specific method of the present invention and the plastic emulsion are mixed at a weight ratio of 4:1 to 1:4 depending on the performance and use of the foam. At this time, in order to be able to freely select the NCO/active hydrogen ratio between the polyisocyanate compound and the plastic emulsion, (A) polyisocyanate, (B) polyethylene oxide derivative, and (C) polyether diol or polyether triol were first selected. It is also possible to obtain a premix and add (A) polyisocyanate and plastic emulsion to this premix. Plastic emulsions contain about 30-70% water, depending on the type of plastic. It is thought that the isocyanate group forms urea bonds, Biuret bonds, etc. while generating carbon dioxide gas by reaction with water.

In the present invention, the foam can be produced without using any reaction catalyst, but catalysts such as tertiary amines and alkali metals can be used.

Mixing of the formulation is done by manual or mechanical stirring, and if the foam is obtained by spraying, 2
A liquid mixing type spray foaming machine is used.

Depending on the use of the foam of the present invention, fillers such as carbon, silica, asbestos, talc, zinc white, bentonite, titanium dioxide, calcium carbonate, calcium sulfate, barium sulfate, and glass fiber may be added to the weight of the foam. Up to an equivalent amount can be added to isocyanate compounds or plastic emulsions to form foams. In addition, in the production of foams that require flame retardancy, chlorinated paraffin, antimony oxide, bisphenol tetrabromide A, diethyl bis(hydroxyethyl) aminomethyl phosphonate (Fyrol6 product name manufactured by Stoffer Chemical Co., Ltd.), etc. Flame retardants can be added to isocyanate compounds or plastic emulsions.

Example 1 To 100 parts by weight of polyphenylmethane polyisocyanate were added 8 parts by weight of methoxypolyethylene glycol with a molecular weight of 700 and 100 parts by weight of a block polyether with a molecular weight of 2500 and a 1/2 molar ratio of ethylene oxide/propylene oxide whose starting material was water. The mixture was reacted at 80°C for 4 hours to obtain a polyisocyanate compound. To 100 parts by weight of this polyisocyanate compound, 0.5 parts by weight of silicone foam stabilizer L-5340 and 100 parts by weight of dibutyl phthalate were added and mixed uniformly to obtain a premix.

Using a two-component mixing type spray foaming machine, premix was placed in one tank and styrene-butadiene latex (manufactured by Nippon Zeon Co., Ltd.) was placed in the other tank.
Nipol4850A) was charged and sprayed at a blending ratio of 1:1 to obtain a uniform foam with a density of 0.40 g/cm ³ .

Comparative Example 1 Polyphenylmethane polyisocyanate was placed in one tank of the spray foaming machine used in Example 1.
100 parts by weight and 0.5 parts by weight of silicone foam stabilizer L-5340,
and 100 parts by weight of dibutyl phthalate were charged, and the other tank was charged with the styrene-butadiene latex used in Example 1, and sprayed at a mixing ratio of 1:1 to 1:3. Liquid dispersion was poor and normal foam could not be obtained.

Comparative Example 2 (corresponding to the one described in Japanese Patent Publication No. 55-7472) 8 parts by weight of methoxypolyethylene glycol having a molecular weight of 700 was added to 100 parts by weight of polyphenylmethane polyisocyanate, and the mixture was reacted at 80°C for 4 hours to form a polyisocyanate. Compound D was obtained. Example 1
100 parts by weight of a polyisocyanate compound, 0.5 parts by weight of silicone foam stabilizer L-5340, and dibutyl phthalate were placed in one tank of the spray foaming machine used in
A uniform mixture of 100 parts by weight was charged, and the other tank was charged with the styrene-butadiene latex used in Example 1, and sprayed at a mixing ratio of 1:1 to 1:3, but the spray product was a dispersion of two liquids. The foam was poor and a satisfactory foam could not be obtained.

Comparative Example 3 (corresponding to that described in Japanese Patent Publication No. 55-7472) Oxypropylated glycerol with a molecular weight of 1000
Add 500 parts by weight to 1025 parts by weight of polyphenylmethane polyisocyanate and stir at 100°C.
Polyisocyanate compound F was obtained by reacting for 2 hours.

Separately, 102.5 parts by weight of methoxypolyethylene glycol with a molecular weight of 620, which was kept at 100°C, was added dropwise to 922.5 parts by weight of polyphenylmethane polyisocyanate, which was also kept at 100°C, and the mixture was stirred and reacted for 30 minutes to obtain surfactant G. .

150 parts by weight of a styrene-butadiene latex was added to 100 parts by weight of the mixture of F and G, and the mixture was rapidly mixed and stirred, but no practical foam could be obtained.

In an experiment in which only the above oxypropylated glycerol was replaced with oxyethylated glycerol having a molecular weight of 1000, a uniform foam could be obtained.

Example 2 Molecular weight added to 100 parts by weight of carbodiimidated modified MDI
6 parts by weight of 700 methoxypolyethylene glycol;
and 1/1 ethylene oxide/propylene oxide with a molecular weight of 3000 and starting material being glycerin.
80 parts by weight of block polyether in a molar ratio was added and reacted at 80°C for 4 hours to obtain a polyisocyanate compound. This polyisocyanate compound
100 parts by weight of acrylonitrile-butadiene latex (Nipol LX531B manufactured by Nippon Zeon Co., Ltd.) 100
When parts by weight were added and rapidly mixed and stirred, the density
A homogeneous foam of 0.45 g/cm ³ was obtained.

Example 3 To 100 parts by weight of polyphenylmethane polyisocyanate were added 5 parts by weight of methoxypolyethylene glycol with a molecular weight of 900 and 100 parts by weight of a block polyether with a molecular weight of 2000 and a 1/1 molar ratio of ethylene oxide/propylene oxide whose starting material was water. The mixture was reacted at 80°C for 4 hours to obtain a polyisocyanate compound. To 100 parts by weight of this polyisocyanate compound, 80 parts by weight of the polyisocyanate compound D obtained in Comparative Example 2 and n-octyl oleate.
A polyisocyanate compound H was obtained by uniformly mixing 100 parts by weight of a mixture of 10 parts by weight and 10 parts by weight of carnauba wax and 100 parts by weight of dibutyl phthalate. When 100 parts by weight of acrylate latex (Nipol LX841 manufactured by Nippon Zeon Co., Ltd.) was added to 100 parts by weight of this polyisocyanate compound H and rapidly mixed and stirred, the density was 0.35 g/ ^cm3 .
A homogeneous foam was obtained.

Example 4 4 parts by weight of malonic acid diester of methoxypolyethylene glycol having a molecular weight of 500 and 40 parts by weight of polyethylene glycol having a molecular weight of 1000 were added to 100 parts by weight of polyphenylmethane polyisocyanate, and the mixture was reacted at 80°C for 6 hours to form a polyisocyanate. The compound was obtained. This polyisocyanate compound
50 parts by weight of chlorinated paraffin (Toyoparax 145, manufactured by Toyo Soda Kogyo Co., Ltd.) was mixed with 50 parts by weight of vinyl chloride latex (manufactured by Nippon Zeon Co., Ltd.).
When 100 parts by weight of Geon 576) was added and rapidly mixed and stirred, a uniform foam having a density of 0.70 g/cm ³ was obtained.

Example 5 50 parts by weight of the premix obtained in Example 1 and 50 parts by weight of the polyisocyanate compound H obtained in Example 3 were uniformly mixed with 96 parts by weight of styrene-butadiene latex (Nipol LX430 manufactured by Nippon Zeon Co., Ltd.). When a mixture of 1 part and 4 parts by weight of ethylene glycol was added and rapidly mixed and stirred, the density
A homogeneous foam of 0.35 g/cm ³ was obtained.

Example 6 100 parts by weight of a concentrated latex (natural rubber latex) with a solid content of approximately 60% was added to 100 parts by weight of the premix obtained in Example 1, and the mixture was rapidly mixed and stirred to form a uniform foam with a density of 0.35 g/cm ³ . Obtained.

Claims (1)

[Claims] 1 (A) 100 parts by weight of diphenylmethane diisocyanate-based polyisocyanate and (B) RO (CH ₂ CH ₂ O) nH or R' (OCH ₂ CH ₂ ).
mOOCCH ₂ COO(CH ₂ CH ₂ O) nR′(R and
R' is the same or different alkyl group having 1 to 4 carbon atoms, n and m are 5 to 120 on average) 1 to 20 parts by weight of a polyethylene oxide derivative;
and (C) ethylene oxide/propylene oxide in a molar ratio of 1/0 to 1/3 with a molecular weight of 200 to
6000 polyether diols and/or polyether triols in an NCO/OH molar ratio of 2
A method for producing a foam comprising mixing a polyisocyanate compound obtained by reaction with a plastic emulsion in a proportion of ~20.