JPH06206959A - Production of dispersion of condensation resin particle - Google Patents

Abstract

PURPOSE:To obtain a dispersion of condensation resin particles having low viscosity and excellent dispersion stability and suitable for the production of polyurethane, etc., by reacting an aldehyde with a compound condensable with aldehyde; etc., in a specific dispersion medium. CONSTITUTION:The dispersion is produced by reacting an aldehyde (or its precondensate) with a compound condensable with the aldehyde (e.g. phenol and urea) in a dispersion medium composed mainly of a mixture of (A) preferably 0.1-20 pts.wt. (based on 100 pts.wt. of the component B) of a blocked polyether of formula [R<1> and R<2> are residues obtained by removing hydroxyl groups from a polyether polyol; n is 2-6; X is ester or urethane (bond); R<3> is 1-10C alkyl or aryl; R<4> is residue obtained by removing functional groups from a compound having 2-6 functional groups reactive with hydroxyl group] and (B) an active hydrogen compound such as a polyether polyol having hydroxyl number of 2-8 and a molecular weight of 100-5,000 per one hydroxyl group, thereby precipitating fine particles of a condensation resin.

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 condensation resin dispersion suitable for producing polyurethane.

[0002]

2. Description of the Related Art Conventionally, as a polyol for a polyurethane raw material, what is called a polymer polyol or a graft polyol is known. This is a polymer in which an addition polymerization system is grafted to the molecular chain of a polyol such as a polyether polyol or an unsaturated polyol, or an addition polymer or other polymer is simply dispersed in the polyol. . This type of polymer polyol can be produced by polymerizing a vinyl monomer such as acrylonitrile or styrene in a liquid polyol, by simply dispersing a polymer such as a vinyl polymer produced in advance in the polyol, or by dispersing the polymer. A method of grafting a polymer on a polyol is known. The polymers in such conventional polymer polyols are mostly vinyl polymers and are a type of thermoplastic resin.
Exceptionally known polymers other than vinyl polymers are linear polyesters and the like, and polymer polyols were obtained by dispersing these in polyols.

[0003]

It has heretofore been known to use an amino resin precondensate as a polyol for a polyurethane raw material. In this case, the amino resin initial condensate has a hydroxyl group capable of reacting with an isocyanate group such as a methylol group, and a polyurethane such as a polyurethane foam has been obtained by the reaction of this initial condensate with a polyisocyanate compound (Japanese Patent Laid-Open Publication No. Sho. 53-16798). Further, it is also known to produce a polyurethane foam by using a polyol mixture obtained by mixing an amino resin initial condensate and a usual polyurethane raw material polyol (see JP-A-52-153000). In this case, the amino resin initial condensate is used. Is also known to be produced in a polyol (see JP-A-54-101848). It is difficult to recognize that the polyol containing the amino resin initial condensate is a kind of polymer polyol. That is, the amino resin initial condensate is a kind of a relatively low molecular weight polyol containing a hydroxyl group such as a methylol group, and is not a high molecular weight polymer recognizable as a polyol in a polymer polyol. Therefore, not only it is difficult to exert the effect of increasing the elasticity of the polyurethane foam, which is a characteristic of the polymer polyol, but also its use is limited to the raw material for the rigid urethane foam.

Further, it is also known to fill a polyurethane with a powder of a crosslinked high molecular weight condensation resin as a filler, but it is difficult to stably disperse this filler in a polyol, and thus the polymer is used. It was not possible to obtain a stable dispersion liquid like a polyol. Of course, this filler has no effect as a filler, that is, an effect of improving the physical properties of polyurethane beyond the effect of increasing the amount and flame retardant, and can substitute for the target polymer polyol, and may be newer or better than that. It was impossible to exert the improved effect. Further, Japanese Patent Publication No. 57-14708 describes a method for producing a dispersion of an aminoplast condensate by condensing a substance capable of forming an aminoplast in a polyhydroxy compound. The compounds are not completely compatible with the aminoplast starting materials or their solutions (especially aqueous solutions), and also with the aminoplast-forming substances, making it difficult to control the reaction uniformly and to ensure that the resin particles are completely It is not possible to obtain stable dispersions, and only those with high particle size are obtained. Polyhydroxy compounds also tend to be limited to those containing a certain concentration of ethylene oxide chains so that they are somewhat compatible with water. There is also a method in which aminoplast condensate particles, which are hard to settle easily, are generated in a dispersion medium containing water and / or an organic solvent as a main component, and subsequently substituted with a polyhydroxy compound (JP-A-2-
No. 91116), even with this method, it is difficult to control the production of aminoplast condensate particles, and a high level production technique is required.

Further, JP-A-51-122153 discloses a method of forming sedimentable particles and blending them with a polyol or the like. However, in this case, the particle size is large and the particles tend to settle in the polyol. In order to improve the dispersion stability of such condensed resin particles, it is necessary to reduce the particle size, but on the other hand, if the particle size is reduced, there is a problem that sedimentation is difficult and filtration separation of particles becomes difficult. . INDUSTRIAL APPLICABILITY The present invention solves various problems in the conventional polymer-containing polyol as a polyurethane raw material, and can be used as a raw material capable of producing a flame-retardant polyurethane, and has good dispersion stability and low viscosity. It is an object of the present invention to provide a novel method for producing the condensation resin dispersion of (1).

[0006]

That is, the present invention is a condensation system in which a compound capable of condensing an aldehyde and an aldehyde or an initial condensation product thereof are reacted in a dispersion medium to precipitate fine condensation resin particles. In the method for producing a resin particle dispersion, as a dispersion medium, a block polyether (a) represented by the following formula (1), R ⁴ [X—R ¹ —O—R ² —O—R ³ ] _n (1 ) R ^1, R ^2: residue obtained by removing the hydroxyl group of polyether polyol having a hydroxyl group, n: 2 to 6 integer, X: ester or urethane bond, R ^3: an alkyl group or an aryl having 1 to 10 carbon atoms Group, R ⁴ : a residue obtained by removing a functional group from a compound having 2 to 6 hydroxyl-reactive functional groups, and an active hydrogen compound (b)
The present invention provides a method for producing a condensed resin particle dispersion, which comprises using a mixture of the above as a main component.

Examples of the active hydrogen compound (b) in the present invention include polyhydroxy compounds such as polyhydric alcohols, amines, polyether polyols obtained by adding alkylene oxides to active hydrogen-containing compounds such as phosphoric acid, and cyclic ether polymers. A polyether polyol or the like is used. Specifically, glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol,
Dextrose, sucrose, other polyhydric alcohols, diethanolamine, bisphenol A, phenol-formaldehyde condensate, other polyhydric phenols, ethylenediamine, diaminodiphenylmethane, propylene oxide, butylene oxide, epichlorohydrin and other alkylene oxides, and also styrene oxide and There are epoxide-added polyether polyols such as glycidyl ether and polyether polyols such as tetrahydrofuran polymers. Two or more of these may be used in combination. A preferred polyether polyol is a polyether polyol having a molecular weight of 100 to 5,000 per OH group, and a polyether polyol having 2 to 8 hydroxyl groups is preferable.

As the block polyether (a) in the present invention, one having a structure represented by the formula (1) is used. In this, R ¹ and R ² are hydroxyl groups 1
The molecular weight per unit is the active hydrogen group of the active hydrogen compound (b) 1
It is preferable that the molecular weight per unit be 100 or more, particularly 300 or more, from the viewpoint of dispersion stability of the produced condensation resin particles. R ¹ or R ² is a residue obtained by removing a hydroxyl group from polyethylene glycol, and the content of the residue obtained by removing a hydroxyl group from polyethylene glycol in the block polyether (a) is 10 to 80% by weight. However, it is still preferable in terms of dispersion stability. X of the block polyether (a) is a bond formed from an arbitrary functional group capable of reacting with a hydroxyl group and the hydroxyl group, but an ester or urethane bond is preferable from the viewpoint of easy reaction. In the case of ester, by reaction with a bifunctional acid halide or acid anhydride or tetracarboxylic acid anhydride, in the case of urethane, by reaction with a known polyisocyanate,
Can be introduced.

One of the raw materials for forming the condensation resin according to the present invention
One is aldehydes. As the aldehydes, derivatives of aliphatic, alicyclic, aromatic, heterocyclic aldehyde compounds, other aldehydes, their condensates, and compounds capable of generating aldehydes can be used alone or in combination. Preferred aldehydes are lower aliphatic aldehydes,
Particularly preferred are aliphatic aldehydes having 4 or less carbon atoms and their derivatives, such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde,
There are isobutyraldehyde, paraformaldehyde, paraacetaldehyde and the like, and formaldehyde is preferable. These aldehydes can be used by dissolving them in a solvent, and a particularly preferable solvent is water, but it is not limited thereto. In the present invention, it is particularly preferable to use an aqueous formaldehyde solution, that is, formalin.

Another raw material for forming a condensation resin is a compound capable of forming a solid condensation resin by condensing with aldehydes (hereinafter referred to as an aldehyde condensation compound), which is at a position capable of reacting with aldehydes (hereinafter , Reaction site) is basically required. The reactive site is typically a hydrogen-bonded oxygen atom in an aromatic group or a hydrogen-bonded nitrogen atom in an amino group or an amide group. As the aromatic reaction site, an aromatic ortho position or para position to which a hydroxyl group or an amino group is bonded is particularly preferable, and it has two or more reaction sites. That is, those having no substituent at this site are suitable, and as the compound having an amino group or an amide group, a polyamine compound having two or more of these groups is basically suitable. Therefore, as the aldehyde-condensable compound, aromatic compounds such as phenols and aromatic amines, and urea, guanidine compounds and other polyamine compounds are preferable. Compounds capable of reacting with these aldehydes may be used in combination of two or more kinds. In addition, with these, 1 reaction site
It is also possible to use a compound having only one compound in combination.

Among the above aromatic compounds, examples of phenols include phenol, cresol, xylenol, P-alkylphenol, P-phenylphenol, bisphenol A, resorcin, and the like. Particularly preferred is phenol, and aromatic Examples of the amine include aniline, diaminobenzene, P-alkylaniline, N-substituted alkylaniline, diphenylamine and diaminodiphenylmethane, and they can be used alone or in combination of two or more in the same manner as the phenol compound.

Since the amino group or amide group of an aromatic amine is itself a reaction site, it may be regarded as one of the following diamine compounds, or may be an aromatic amino group or amide group. There may be one reactive site other than. The particularly preferable aromatic compounds are not limited to the above compounds, and aromatic hydrocarbons such as benzene and xylene and other compounds can be used. Further, phenols and aromatic amines can be used in combination, and at least one of them can be further combined with other aromatic compounds.

The polyamine compound is preferably a compound basically having two or more amino groups or amide groups, and among them, a compound having two or more amino groups is preferable, for example, urea,
Urea such as thiourea and N-alkyl-substituted urea, melamine compounds such as melamine and N-alkyl-substituted melamine, and S-triazines having two or more amino groups represented by guanamine compounds such as benzoguanamine and acetoguanamine, guanidine Guanidines such as substituted guanidine, aminoguanidine hydrochloride, dicyandiamide and the like are preferable, and particularly preferable among these are urea, melamine and benzoguanamine. These polyamine compounds are used in combination of two or more kinds, for example, urea-thiourea, urea-melamine,
A combination of urea-benzoguanamine, urea-melamine-benzoguanamine, melamine-dicyandiamide and the like can also be used. It is also possible to use the polyamine compound and the aromatic compound in combination, and as such a combination, for example, phenol-urea, phenol-melamine, aniline-urea, aniline-melamine, phenol-aniline-melamine, phenol- Urea-melamine and other combinations are included.

Further, as the aldehyde-condensable compound, in addition to the above compounds, a ketone compound known as a raw material for a ketone resin may be used. The compounds having at least two reaction sites with aldehydes described above are compounds having one reaction site or compounds having two or more sites themselves, such as dialkanolamines, monoalkanolamines, and fats. It can also be used in combination with a group amine. Further, in the present invention, an initial condensate of an aldehyde condensable compound and an aldehyde, such as dimethylol urea, hexamethylol melamine, hexamethoxydimethyl melamine, etc., can also be used as a forming raw material.

In the reaction for forming the condensation resin particles, the ratio of the aldehyde-condensable compound and the aldehydes is not particularly limited as long as the ratio theoretically includes the ratio of the condensation resin. This is because even if the unreacted aldehyde condensable compound remains, it may be contained in the produced dispersion as long as the amount thereof is not excessive, and the unreacted aldehyde can be removed when the dispersion medium is removed. The aldehydes are preferably 5 to 50 relative to 100 parts by weight of the aldehyde condensable compound.
0 parts by weight, especially 10 to 200 parts by weight are used.

The condensation resin produced by this reaction is considered to be similar to or the same as a cured product of a conventionally known condensation thermosetting resin such as a phenol resin, a urea resin, and a melamine resin. Is also considered to be the same. Taking the case of using formaldehyde as the aldehyde, for example, the aldehyde-condensable compound and formaldehyde are added and condensed in the initial stage of the reaction to produce various methylol group-containing compounds. The above-mentioned initial condensate, which is one of the forming raw materials of the present invention, corresponds to the methylol addition compound at this stage. After this, it is considered that the methylol group-containing compound is dehydrated and condensed, so that the methylol group becomes a methylene group and is condensed to become a condensation resin that is insoluble and infusible in a solvent that is three-dimensionally crosslinked.

The present invention is a method characterized in that the condensation reaction is basically completed. The particle size of the condensed resin fine particles obtained in the present invention is preferably in the range of 0.01 to 5 µ, particularly preferably in the range of 0.1 to 2 µ. This is because if it exceeds 5 μm, it tends to precipitate in the active hydrogen-containing compound such as polyol. It is preferable that the condensed resin fine particles do not substantially settle for at least 1 month, preferably 2 months or more when left standing.

The process of obtaining the condensable resin compound will be described in more detail below. The aldehyde condensable compound and the aldehyde react with each other at room temperature to under heating and / or under pressure. It is considered that at relatively low temperatures, methylol group-containing compounds to which aldehydes are added and low molecular weight condensates are likely to be formed, and at relatively high temperatures, methylene bridges and dimethylene ether bonds due to dehydration reaction of methylol groups are likely to be produced. ing. Of course, the compound produced does not depend only on the reaction temperature, but changes depending on the charging ratio of various constituent units, the pH of the additives such as catalysts, and the like. However, considering only the reaction temperature, in the present invention, it is preferable to carry out the reaction at a relatively low temperature before the reaction and at a relatively high temperature after the reaction. In particular, a relatively high temperature in the latter stage of the reaction is often necessary because a condensation reaction of a hydroxyalkyl group such as a methylol group occurs. Therefore, in the first stage of the reaction, the temperature is about 80 ° C or lower, and in the latter stage, the temperature is higher than the former stage by 10 ° C or more and about 60 ° C.
It is preferable to carry out the reaction at a temperature of not less than ° C. The upper limit temperature in the latter stage of the reaction is preferably a temperature at which a side reaction other than the decomposition of the active hydrogen-containing compound and the condensation resin-forming reaction does not easily occur, and for example, a temperature of about 80 ° C to 200 ° C is preferable.

Acids such as hydrochloric acid and acetic acid, and bases such as NaOH and triethylamine can be used as catalysts in order to promote the condensation reaction at a relatively low temperature. It is also effective to add a small amount of a particle dispersion stabilizer such as a surfactant during the condensation reaction in order to increase the stability of the condensation resin particles. Furthermore, a curing agent such as hexamethylenetetramine,
It is also possible to react in the presence of various additives such as a dispersion stabilizer and a coloring agent. It is not preferable that the active hydrogen-containing compound used as a raw material for polyurethane contains a relatively large amount of water. Therefore, also in the present invention, when an aqueous solution of an aldehyde is used and water is present in the system, it is necessary to remove the water after the reaction is completed. Water can usually be removed by heating or under reduced pressure. The dispersion amount of the condensation resin in the dispersion of the present invention is not particularly limited as long as the condensation resin is stably dispersed, but if it is excessive, the dispersion stability decreases and the viscosity becomes high. Usually, the content of the condensation resin fine particles in the dispersion is preferably 80% by weight.
It is particularly preferably 50% by weight or less. Although there is no particular lower limit, in order to exert the effect of the dispersion of the present invention in the production of polyurethane, it is preferable that condensed resin fine particles are present in the dispersion in an amount of at least 2% by weight, particularly about 5% by weight.

The condensation resin dispersion of the present invention obtained as described above is preferably a white or colored translucent or opaque viscous liquid in which condensation resin particles having a particle diameter of 0.1 to 5 μm are dispersed. Further, it is preferable that the present dispersion does not cause separation for at least about 1 month, particularly at least 2 months in a stationary state, but of course, it is not limited to this time. It can be presumed that the reason why the product of the present invention is excellent in such dispersion stability is that the system of the condensation resin fine particles is fine and uniform. As described above, in the dispersion of the present invention, the condensation type resin is one in which condensation has proceeded sufficiently, and therefore it has almost no functional group containing a hydroxyl group such as a methylol group. Compared to that of the active hydrogen-containing compound that is the dispersion medium, it does not increase significantly, and is lower than the hydroxyl value of the active-hydrogen-containing compound in proportion to the content of the condensation resin, so the hydroxyl value of the dispersion is It is preferably 1.2 times or less, and particularly equal to or less than that of the active hydrogen-containing compound. However, as an aldehyde condensable compound,
When a hydroxyl group-containing compound such as a phenol compound is used, the hydroxyl value of the dispersion may be higher than that of the active hydrogen-containing compound. In the case of a known amino resin initial condensate-containing polyol, if the hydroxyl value of the used polyol is higher than that of the amino resin initial condensate, the hydroxyl value of the dispersion polyol will be lower than that of the original polyol, but dimethylol When a high hydroxyl value of about 600 or more such as urea or follymethylol melamine is used as a component of the amino resin initial condensate, a dispersion obtained by using a polyol having a low hydroxyl value (that is, a high molecular weight) is The hydroxyl value is much higher than that of the polyol.

The condensation resin dispersion of the present invention obtained by the above-mentioned production method is suitable for use as a part or all of the active hydrogen-containing compound as the main raw material in the production of polyurethane. In addition, the condensation resin dispersion of the present invention containing a relatively low molecular weight active hydrogen-containing compound can also be used as a part or all of a cross-linking agent which is an auxiliary raw material of polyurethane. Whereas conventional polymer polyols rather reduce the flame retardancy of polyurethane, the condensation-type resin of the present invention improves the flame retardancy of polyurethane. In particular, the condensation resin dispersion of the present invention, which mainly uses a phenol compound, a urea compound, a melamine compound, a guanamine compound, or a guanazine compound, is particularly effective for improving the flame retardancy of polyurethane. Accordingly, the present invention also relates to the use of a condensation resin dispersion, which is used to produce a polyurethane prepared from a polyisocyanate compound and an active hydrogen-containing compound containing two or more active hydrogen groups capable of reacting with an organic isocyanate compound. In the method described above, a method for producing a polyurethane can be provided which is characterized by using the condensation resin dispersion of the present invention as a part or all of the active hydrogen-containing compound. As a polyol used as a basic raw material of polyurethane, a high molecular weight polyol having a molecular weight of 300 to 3000 per hydroxyl group is generally used, and a molecular weight of 500 to 3000 per hydroxyl group is particularly preferred, and a hydroxyl group having 2 to 8 hydroxyl groups in the molecule is used. A polyether polyol is used, and a polyol having a lower molecular weight than the above is used for a rigid polyurethane foam. Therefore, when the condensation resin dispersion of the present invention is used as a part of a raw material for polyurethane, the above-mentioned conventionally used high molecular weight polyol is suitable as another polyol to be used in combination therewith.
In the production of polyurethane, a crosslinking agent comprising a relatively low molecular weight active hydrogen-containing compound containing two or more active hydrogens such as polyhydric alcohols, alkanolamines and polyamines as a basic raw material for polyols and polyisocyanate compounds is used. There are cases. The condensation resin dispersion, particularly the condensation resin dispersion obtained by using the low molecular weight polyol, can be used as a part or all of the crosslinking agent.

Polyurethane foam is most suitable as the polyurethane in the present invention. The condensation type resin dispersion of the present invention can be used in the same manner as a conventional polymer polyol to obtain a polyurethane foam having high performance. The use of blowing agents is usually necessary in the production of polyurethane foam. As the foaming agent, water, trichlorodifluoromethane, dichlorodifluoromethane, methylene chloride or other halogenated hydrocarbon is used.
Furthermore, a component often required in the production of polyurethane foams is a foam stabilizer. Suitable foam stabilizers are poly (dialkylsilanes), polyoxoalkylene chain-containing silanes and other organosilicon compounds, but in some cases fluorine-based surfactants can be used. Catalysts are commonly used in the production of foamed or non-foamed polyurethanes. As the catalyst, various tertiary amines and other amine compounds and organic tin compounds are used alone or in combination. Various additives such as stabilizers, fillers, reinforcing agents, colorants, mold release agents, crosslinking agents, chain extenders and flame retardants can be used as raw materials for other foamed or non-foamed polyurethanes.

Another basic raw material for polyurethane is a polyisocyanate compound. As the polyisocyanate compound, compounds having at least two isocyanate groups such as aromatic compounds, aliphatic compounds, alicyclic compounds, and heterocyclic compounds can be used alone or in combination, and particularly aromatic polyisocyanates. The use of compounds is preferred. Specific examples of the polyisocyanate compound include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymethylene polyphenyl isocyanate, xylylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate and isophorone diisocyanate. The polyisocyanate compound can also be used as a modified polyisocyanate compound modified by various methods or compounds, and can also be used as a blocked isocyanate compound blocked with various compounds. The method for producing polyurethane using these raw materials is not particularly limited, and for example, a one-shot method, a prepolymer method, a RIM method or the like can be used. In the present invention, the dispersion stability is good, and the action mechanism by which a low-viscosity condensed resin dispersion is obtained is not always clear, but the condensed resin particles are basically fine and uniform, and a polyol is basically It can be presumed that many particles exist independently without reacting.

[0024]

EXAMPLES The present invention will be specifically described below with reference to examples, but the parts in each example mean parts by weight. The present invention is not limited to these examples. Reference Example 1 Ethylene oxide was added to polyoxypropylene monool having a molecular weight of 3000 using n-butanol as an initiator, and 400 parts of polyoxyethylene propylene monool having a molecular weight of 4000 was reacted with 9.2 parts of tolylene diisocyanate. Then, by degassing, a block group polyether containing a urethane group was obtained.

Reference Example 2 A reaction was performed in the same manner as in Reference Example 1 except that 9.2 parts of tolylene diisocyanate of Reference Example 1 was changed to 8.8 parts of hexamethylene diisocyanate to obtain a block polyether containing a urethane group. .

Reference Example 3 A reaction was conducted in the same manner as in Reference Example 1 except that 9.2 parts of tolylene diisocyanate of Reference Example 1 was changed to 26.4 parts of hexamethylene diisocyanate trimer to obtain a block poly containing a urethane group. Obtained ether.

Reference Example 4 400 parts of polyoxyethylene propylene monool having a molecular weight of 4000 used in Reference Example 1 and phthalic anhydride 7.
4 parts were reacted to obtain a block polyether containing an ester group.

Reference Example 5 400 parts of polyoxyethylene propylene monool having a molecular weight of 4000 used in Reference Example 1 and 1,2,4,5-
By reacting with 10.9 parts of benzenetetracarboxylic dianhydride, a block polyether containing an ester group was obtained.

Example 1 Melamine 50 parts, 35% formaldehyde aqueous solution 70
Parts, 30 parts of the block polyether of Reference Example 1 and 120 parts of polyoxyethylene propylene triol having a molecular weight of 3,000 were charged in a reactor, heated to 80 ° C., stirred for 2 hours, and further reacted at 100 ° C. for 2 hours. It was Water in the system was removed at 100 ° C. to obtain a white viscous emulsion. The hydroxyl value is 33.7 and the viscosity is 3200 cp (25
℃). It was found that the solid particles in this polyol were stably dispersed for 2 months or more without being separated from the polyol.

Examples 2-5 Instead of the block polyether used in Example 1,
The block polyethers of Reference Examples 2 to 5 were used and reacted in the same manner as in Example 1. The appearance was a white viscous emulsion. The results are summarized in Table 1.

[0031]

[Table 1]

Comparative Example 1 A white viscous emulsion was prepared in the same manner as in Example 1 except that the block polyether of Example 1 was not used at all and 150 parts of polyoxyethylene propylene triol having a molecular weight of 3000 was used. However, the precipitation was partially observed immediately after the synthesis because of the large particle size, and the dispersion stability was very poor.

Example 6 30 parts of urea, 10 parts of dicyandiamide, 80 parts of 35% aqueous formaldehyde solution, 24 parts of the block polyether of Reference Example 1 and 96 parts of polyoxyethylene propylene triol having a molecular weight of 3000 were charged to a reactor and heated to 80 ° C. After the temperature was raised and stirring was continued for 2 hours, the reaction was further performed at 100 ° C. for 2 hours. Water in the system was removed at 100 ° C. to obtain a white viscous emulsion. Hydroxyl value is 35.6, viscosity is 320
It was 0 cp (25 ° C). It was found that the solid particles in this polyol were stably dispersed for 2 months or more without being separated from the polyol.

Comparative Example 2 A white viscous emulsion was prepared in the same manner as in Example 6 except that the block polyether of Example 6 was not used at all and 120 parts of polyoxyethylene propylene triol having a molecular weight of 3000 was used. However, the precipitation was partially observed immediately after the synthesis because of the large particle size, and the dispersion stability was very poor.

[0035]

EFFECT OF THE INVENTION By using the dispersion stabilizer of the present invention, it becomes possible to obtain a stable dispersion even in a system in which it has been difficult to stably disperse a condensation resin in the past.

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Claims (6)

[Claims] 1. A method for producing a condensation resin particle dispersion, which comprises reacting a compound capable of condensing with an aldehyde with an aldehyde or an initial condensation product thereof in a dispersion medium to deposit fine condensation resin particles, As the dispersion medium, a block polyether (a) represented by the following formula (1), R ⁴ [X—R ¹ —O—R ² —O—R ³ ] _n (1) R ¹ and R ² : a hydroxyl group Residue excluding hydroxyl groups of the contained polyether polyol, n: integer of 2 to 6, X: ester or urethane bond, R ³ : alkyl group or aryl group having 1 to 10 carbon atoms, R ⁴ : 2 to 6 A residue obtained by removing a functional group from a compound having a hydroxyl-reactive functional group, and an active hydrogen compound (b)
A method for producing a condensation-type resin particle dispersion, which comprises using the mixture as a main component. 2. The active hydrogen compound (b) has a hydroxyl group number of 2 to 2.
8. The method according to claim 1, wherein the polyether polyol is 8 and the molecular weight per hydroxyl group is 100 to 5,000. 3. R ¹ and R of the block polyether (a)
² is a residue of polyether diol excluding the hydroxyl group, and half of the total molecular weight of R ¹ and R ² is 100 or more larger than the molecular weight per active hydrogen group of the active hydrogen compound (b). The method described. 4. R ¹ and R of the block polyether (a)
Either of ² is a residue obtained by removing a hydroxyl group from polyethylene glycol, and the content of the residue obtained by removing a hydroxyl group from polyethylene glycol in the block polyether (a) is 10 to 80% by weight. The method described. 5. The block polyether (a) is used in an amount of 0.1 to 100 parts by weight of the active hydrogen compound (b).
The method according to claim 1 or 3, which is 20 parts by weight. 6. The method according to claim 1, wherein the content of the condensation resin particles in the obtained condensation resin dispersion is 5 to 80% by weight.