JPS6337809B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention has good water dispersibility, easy preparation of an aqueous dispersion, and high stability of the obtained aqueous dispersion, and the aqueous dispersion has transparency, smoothness,
The object of the present invention is to provide a manufacturing method that can inexpensively and reliably manufacture a water-dispersible urethane polymer that exhibits excellent properties such as gloss and mechanical strength and also has a film-forming ability. Various water-dispersible polymers are used in the fields of processing agents for paper, fibers, etc., coating agents for paints and inks, and adhesives, and one of them is aqueous dispersions of urethane polymers. Many proposals have been made regarding methods for producing water-dispersible urethane polymers. The main methods for producing water-dispersible urethane polymers include the method of converting a polyol polycarboxylic acid polymer containing a rosin derivative into urethane (Japanese Patent Application Laid-Open No. 143306/1983), and the method of converting polycarboxylic acid into polyurethane polyol. A method in which a polyalkylene polyamine or the like is reacted with a urethane prepolymer (Japanese Patent Application Laid-Open No. 50-112490), and a method in which a compound having an ionic group is reacted as a chain extender. A method in which dimethylolpropionic acid is used as a chain extender (US Pat. No. 3,412,054); Method using half-esterified reaction product of polyhydric alcohol and acid anhydride (JP-A-49-128995, JP-A-51-
41098), but in all of the three methods, the resulting urethane polymer has insufficient water dispersibility, and a relatively large amount of hydrophilic organic solvent is required to obtain the aqueous dispersion of the urethane polymer. The manufacturing process itself is complicated, and there is a risk of gelation.The resulting aqueous dispersion of urethane polymer is also unstable, causing phenomena such as separation, aggregation, and thickening. It has the disadvantage of being easy to
In addition, in the latter method in which a compound having an ionic group is reacted as a chain extender, there is a high risk of gelation during the manufacturing process of water-dispersible urethane polymer, and the aqueous dispersion of urethane polymer has a high viscosity. Therefore, when using the dispersion liquid, the workability is poor and the applications are limited, and when dimethylolpropionic acid is used as a chain extender, the dimethylolpropionic acid itself, which is the chain extender, is It has disadvantages such as being difficult to obtain and expensive. Furthermore, the films obtained by forming aqueous dispersions of the above-mentioned urethane polymers have poor transparency and are cloudy, and have problems in smoothness, gloss, mechanical strength, etc. All of the aqueous dispersions using urethane polymers have the disadvantage that they do not have the ability to form films with excellent properties. In the present invention, a half-esterification reaction product of a specific polyhydric alcohol and a specific acid anhydride is added to a urethane prepolymer having terminal isocyanate groups in an amount such that the acid value of the resulting urethane polymer is 20 or more. It is used as a chain extender and reacted to produce a urethane polymer having carboxyl groups, and the carboxyl groups in the resulting urethane polymer are neutralized with an inorganic or organic alkaline substance. It is easy to prepare an aqueous dispersion of a urethane polymer by dispersing it in an aqueous medium in a state in which the urethane polymer is dispersed in an aqueous medium. It is possible to reliably and easily obtain a water-dispersible urethane polymer having properties such as a film-forming ability that exhibits excellent properties such as transparency, smoothness, gloss, and mechanical strength. The present invention provides a manufacturing method that allows for In the present invention, a urethane polymer is obtained by reacting a urethane prepolymer with a chain extender. The chain extender is reacted in an amount such that the resulting urethane polymer has an acid value of 20 or more. [However, A in the formula is

[Formula] (R ₁ is H, COOH, or alkyl group)

【formula】

[Formula] and

[Formula] B represents a divalent organic residue selected from the following, and B represents a trivalent aliphatic residue. ] In the present invention, the urethane prepolymer having terminal isocyanate groups, which is the reaction partner of the chain extender consisting of the compound represented by the general formula [], is a polyether polyol, polyester polyol, or other polyol compound or their It is a compound having a terminal isocyanate group that is prepared by reacting the mixture with a polyisocyanate compound, and it is preferable to use a compound having an average molecular weight of about 300 to 5,000. Specific examples of polyisocyanate compounds include tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI),
Aromatic or aliphatic polyisocyanate compounds such as hexamethylene diisocyanate (HMDI) can be utilized. Moreover, in addition to the above-mentioned prepolymer, the above-mentioned polyisocyanate compound can also be mixed and used in the urethane-based prepolymer having terminal isocyanate groups. In the method of the present invention, the compound represented by the general formula [ ], which is the chain extender reacted with the urethane-based brepolymer having terminal isocyanate groups, is phthalic acid, trimellitic acid, endicic acid, tetrahydrophthalic acid, hexahydrophthalic acid. A half ester of a polycarboxylic acid having a carbon six-membered ring structure selected from acids or anhydrides thereof, an anhydride thereof, preferably an anhydride, and an aliphatic compound having three primary hydroxyl groups. It can be easily and economically obtained by chemical reaction. Furthermore, as the aliphatic compound having three primary hydroxyl groups used in this half-esterification reaction, trimethylolethane and trimethylolpropane are particularly preferred. On the other hand, a compound similar to the compound represented by the above general formula [], which is obtained by a half-esterification reaction of a polycarboxylic acid having a six-membered carbon ring structure or its anhydride with glycerin, is used as a chain extender. The urethane polymer obtained when used as a urethane polymer has insufficient water dispersibility, and the aqueous dispersion obtained by dispersing it in an aqueous medium has properties such as thickening and gelling, so it is preferable. do not have. In addition, the A part in the general formula [] is -CH ₂ -CH ₂
−, −CH ₂ −CH ₂ −CH ₂ −, or −CH ₂ =CH ₂
- When a half-esterification reaction product represented by a chain aliphatic group such as Due to its considerable reactivity with the isocyanate groups in the polymer, it has a very strong tendency to gel during the manufacturing process of the urethane polymer, and the resulting urethane polymer has poor water dispersibility, and the aqueous dispersion itself The stability of the aqueous dispersion is also poor, and the film obtained by forming this aqueous dispersion is opaque and has disadvantages such as extremely poor smoothness and mechanical strength. Among the chain extenders represented by the general formula [] used in the present invention, particularly preferred are:
A in the general formula [] is

[Formula] or

This is the case of a half-esterification reaction product represented by a divalent organic residue represented by [Formula], and when the former compound is used as a chain extender, it is transparent or translucent and has a relatively high It is possible to prepare aqueous dispersions of urethane polymers in the form of viscous solutions, and when the latter compound is used as a chain extender, urethane polymers in the form of low-viscosity, milky-white emulsions with extremely fine particle sizes can be prepared. It has the property of being able to prepare aqueous dispersions of polymers. The chain extender represented by the general formula [ ] having the above structure has a structure in which the carboxyl group is directly bonded to the carbon atom constituting the 6-membered carbon ring. During the manufacturing process of polyurethane polymers, when the terminal isocyanate group of the urethane prepolymer reacts with the chain extender, the reaction between the carboxyl group and the chain extender is minimized to prevent gelation. Therefore, carboxyl groups are effectively introduced into the urethane polymer obtained, and as a result, the urethane polymer obtained by the method of the present invention has excellent water dispersibility. Furthermore, the urethane polymer obtained by the method of the present invention has a structure in which the ester bond between the main chain of the urethane polymer and the side chain having a carboxyl group is protected by a six-membered carbon ring structure. The structure is resistant to hydrolysis, and such properties can lead to aqueous dispersions with good stability. In the method of the present invention, the reaction between the urethane prepolymer having terminal isocyanate groups and the chain extender consisting of the compound represented by the general formula [] can be carried out in accordance with the usual synthesis reaction procedure for urethane polymers. I can do it. For example, an organic solvent that is inert to the functional groups of the urethane prepolymer component and chain extender component used and capable of dissolving each reaction component and the urethane polymer produced by the reaction is used as the reaction medium. ~100℃, preferably
It is desirable to carry out the reaction at a temperature of about 40 to 80°C, using a urethanization reaction catalyst if desired. When reacting this urethane prepolymer with a chain extender, it is necessary to react the chain extender in an amount such that the acid value of the urethane polymer obtained is 20 or more. It is preferable to react at a ratio of about 0.5 to 1.5 moles of chain extender per 1 mole. The acid value of the urethane polymer obtained by the reaction of the urethane prepolymer and chain extender described above is
If it is less than 20, the water dispersibility of this urethane polymer is insufficient, and when obtaining an aqueous dispersion using this urethane polymer, mechanical forced emulsification operation using an emulsifying machine, surfactant, etc. This is not preferred because other dispersants such as protective colloids are required. On the other hand, a urethane polymer obtained by using an amount of a chain extender such that the acid value of the urethane polymer obtained is 20 or more, particularly 40 or more has extremely good water dispersibility, and A stable aqueous dispersion can be obtained. In addition, when reacting this urethane prepolymer with a chain extender, other monofunctional or polyfunctional compounds such as phenol compounds and alcohols may be used to adjust the molecular weight of the urethane polymer produced. Of course, you can use it as appropriate. In the method of the present invention, the urethane polymer obtained has different properties depending on the type of urethane prepolymer used in its production, the molecular weight, the type of chain extender, etc., and the urethane polymer is dispersed in water. Since the properties of the resulting aqueous dispersions are different, the type of urethane prepolymer, molecular weight, type of chain extender, etc. may be adjusted according to the conditions described above depending on the use and purpose of the aqueous dispersion of the urethane polymer. A urethane polymer exhibiting desired properties can be obtained by appropriately changing the conditions within a satisfactory range. The urethane polymer obtained by the method of the present invention having the above structure is dispersed in an aqueous medium with the carboxyl groups in the urethane polymer neutralized with an inorganic or organic alkaline substance. The resulting aqueous dispersion can be used as is or in combination with pigments, dyes, or other aqueous vehicle components to be used as a processing agent for paper and other textile materials. Water-based coating agents, water-based paints, water-based inks,
It can be used as a raw material for adhesives, etc.
It has a wide range of uses. Hereinafter, the specific structure of the method for producing a water-dispersible urethane polymer of the present invention will be clarified using production examples and examples, and the properties of the aqueous dispersion of the urethane polymer obtained will be explained using comparative examples. In comparison with the properties of a dispersion of urethane polymer,
To clarify. Production Example 1 Preparation of polyester diol Two types of dicarboxylic acid components X and Y shown in Table 1 below and 1,4-butanediol (1,4-BDO)
are heated and dehydrated in the presence of 0.3% by weight of dibutyltin oxide based on the total weight of both at 200 to 220°C until the acid value becomes 1 or less, resulting in four types of polyester diols (a) and (ro). ), (c), and (d) were prepared. The results are summarized in Table 1.

[Table] Production Example 2 Preparation of chain extender 1 mole of the acid anhydride shown in Table 2 below and 1 mole of trihydric alcohol are reacted at 80 to 95°C to produce the chain extender which is the corresponding half-esterification reaction product. (a) to (j) were prepared. During the reaction, an appropriate amount of ethyl acetate was used to adjust the viscosity. The results are summarized in Table 2. The chain extenders (a) to (f) are half-esterification reactants used in the method of the present invention, and the chain extenders (g) to (j) are half-esterification reactants for comparison.

【table】

[Table] Example 1 Polyester diol obtained in Production Example 1 above
(a) Dissolve 71g (0.1 mol) in 105g of acetone,
34.8 g (0.2 mol) tolylene diisocyanate and 0.13 g dibutyltatine dilaurate as catalyst
was added and reacted at 50 to 60°C to prepare a urethane prepolymer having terminal isocyanate groups. To the obtained urethane prepolymer, 56 g of an acetone solution containing 28.2 g (0.1 mol) of the chain extender (a) obtained in Production Example 2 was added, and the mixture was allowed to react at a reflux temperature of 60 to 65°C for 3 hours. , an acetone solution of a water-dispersible urethane polymer was obtained. The obtained acetone solution was subjected to a distillation operation to remove part of the acetone, then 50 g of an aqueous solution containing 11 g of dimethylethanolamine (DMEA) was added, stirred and dispersed, and further diluted by adding 300 g of water. , an acetone-water urethane polymer dispersion was obtained. Thereafter, this was further distilled under reduced pressure to almost completely remove acetone, yielding 450 g of an aqueous dispersion of urethane polymer with a non-volatile content of 30.2%. The properties of the obtained aqueous dispersion [ ] and the transparency of the film formed from the aqueous dispersion are summarized in Table 3 together with the acid value (calculated value) of the urethane polymer. Example 2 Among the operations in Example 1, chain extender
Instead of using 0.1 mol, 0.1 mol of the chain extender (b) obtained in Production Example 2 was used, and instead of using 50 g of an aqueous solution containing 11 g of dimethylethanolamine, 50 g of an aqueous solution containing 22 g of dimethylethanolamine was used. All operations were performed in the same manner as in Example 1 except for
An aqueous dispersion of urethane polymer was obtained. The properties of the obtained aqueous dispersion [ ] and the transparency of the film formed from the aqueous dispersion are shown in Table 3 together with the acid value (calculated value) of the urethane polymer. Examples 3 to 6 Among the operations in Example 1, chain extender (a)
The procedure was repeated in the same manner as in Example 1 except that 0.1 mol of each of the chain extenders (c) to (f) obtained in Production Example 2 was used instead of 0.1 mol of the four types of urethane polymers. Aqueous dispersions [] to [] were obtained. The properties of the obtained aqueous dispersion [] to [] and the transparency of the film formed from the aqueous dispersion were determined by
Along with the acid value (calculated value) of the urethane polymer, the third
Shown in the table. Comparative Examples 1 to 4 Among the operations in Example 1, chain extender (a)
Except that 0.1 mol of each of the chain extenders (g) to (j) obtained in Production Example 2 was used instead of 0.1 mol.
All operations were conducted in the same manner as in Example 1 to obtain four types of aqueous dispersions of urethane polymers [] to []. The properties of the obtained aqueous dispersion [] to [] and the transparency of the film formed from the aqueous dispersion were determined by
They are summarized in Table 3 along with the acid value (calculated value) of the urethane polymer.

【table】

[Table] Example 7 Polyester diol obtained in Production Example 1 above
(b) Dissolve 93g (0.1 mol) in 130g of acetone,
50 by adding 34.8 g (0.2 mol) of tolylene diisocyanate and 0.13 g of dibutyltin dilaurate.
The reaction was carried out at ~60°C to prepare a urethane prepolymer having terminal isocyanate groups. To the obtained urethane prepolymer, 56 g of an acetone solution containing 28.2 g (0.1 mol) of the chain extender (a) obtained in Production Example 2 was added, and the mixture was allowed to react at a reflux temperature of 60 to 65°C for 3 hours. , an acetone solution of a water-dispersible urethane polymer was obtained. The obtained acetone solution was subjected to a distillation operation to remove part of the acetone, and then 50 g of an aqueous solution containing 11 g of dimethylethanolamine (DMEA) was added, stirred and dispersed, and further diluted with 350 g of water.
An acetone-water urethane polymer dispersion was obtained. Thereafter, this was further distilled under reduced pressure to almost completely remove acetone, yielding 520 g of an aqueous dispersion of urethane polymer with a non-volatile content of 30.5%. The properties of the obtained aqueous dispersion [ ] and the transparency of the film formed from the aqueous dispersion are shown in Table 4 along with the oxidation of the urethane polymer (calculated values). Example 8 In the operation in Example 7, instead of using 0.1 mol of polyester diol (B), 113 g of polyester diol (C) obtained in Production Example 1 was used.
All operations were conducted in the same manner as in Example 7 except that (0.1 mol) was used to obtain an acetone solution of the urethane polymer. After distilling off part of the acetone from the obtained acetone solution, dimethylethanolamine (DMEA)
50 g of an aqueous solution containing 11 g was added, stirred and dispersed, and further 420 g of water was added to obtain an acetone-water urethane polymer dispersion. After that, this was further distilled under reduced pressure to almost completely remove the acetone and remove the non-volatile components.
30.1% aqueous dispersion of urethane polymer [ ]
Obtained 595g. The properties of the obtained aqueous dispersion [ ] and the transparency of the film formed from the aqueous dispersion are shown in Table 4 together with the urethane polymer acid value (calculated value). Comparative Example 5 In the procedure of Example 7, 281 g (0.1 mol) of polyester diol (d) in Production Example 1 was used instead of 0.1 mol of polyester diol (b), and 130 g of acetone was added to dissolve the polyester diol. The procedure was repeated in the same manner as in Example 7, except that 280 g of acetone was used instead, to obtain an acetone-water urethane polymer dispersion. The obtained dispersion was further diluted with 450 g of water, and the acetone was distilled off under reduced pressure to obtain an aqueous dispersion of urethane polymer with a non-volatile content of 30.0%.
]1152g was obtained. The properties of the obtained aqueous dispersion [ ] and the transparency of the film formed from the aqueous dispersion are shown in Table 4 together with the acid value (calculated value) of the urethane polymer. Example 9 Polyester diol obtained in Production Example 1 above
(a) Dissolve 142g (0.2) mol in 200g of acetone,
52.2 g (0.3 mol) of tolylene diisocyanate and 0.13 g of dibutyltin dilaurate were added.
The reaction was carried out at ~60°C to prepare a urethane prepolymer having terminal isocyanate groups. To the obtained urethane-based prepolymer, 56 g of an acetone solution containing 28.2 g of the chain extender (a) obtained in Production Example 2 was added, and the mixture was reacted at a reflux temperature of 60 to 65°C for 3 hours to improve water dispersibility. An acetone solution of urethane polymer was obtained. Add 50g of an aqueous solution containing 11g of DMEA to the resulting acetone solution, stir and disperse, then add 700g of water.
was added to dilute the mixture to obtain an acetone water-based polyurethane resin dispersion. This was further distilled under reduced pressure to remove acetone, yielding 900 g of an aqueous dispersion of urethane polymer with a nonvolatile content of 25.0%. Table 4 shows the properties of the obtained aqueous dispersion [ ] and the acid value (calculated value) of the urethane polymer. Comparative Example 6 In the procedure of Example 9, 213 g (0.3 mol) of polyester diol (A), 280 g of acetone, and 280 g of tolylene diisocyanate were used instead of 0.2 mol of polyester diol (A), 200 g of acetone, and 0.3 mol of tolylene diisocyanate. Range isocyanate
An acetone solution of the urethane polymer was obtained by carrying out the same procedure as in Example 9 except that 69.6 g (0.4 mol) was used. 50 g of an aqueous solution containing 11 g of DMEA was added to the obtained acetone solution, stirred and dispersed, and then water was added dropwise, but the urethane polymer separated and aggregated and dispersion was impossible. The acid value (calculated value) of the urethane polymer obtained in this example was 18.5. Example 10 In the operation in Example 1, 70 g of commercially available polypropylene glycol with an average molecular weight of 700 [NOF Co., Ltd.
An aqueous dispersion of urethane polymer was obtained in the same manner as in Example 1, except that Uniol D-700 (manufactured by Co., Ltd.) was used. Example 11 In the operation in Example 2, 70 g of commercially available polypropylene glycol with an average molecular weight of 700 [NOF Co., Ltd.
Except for using Uniall D-700 manufactured by Co., Ltd.,
All operations were conducted in the same manner as in Example 2 to obtain an aqueous dispersion of urethane polymer. Comparative Examples 7-8 Among the operations in Example 10, chain extender (a)
The procedure was repeated in the same manner as in Example 10 except that 0.1 mol each of the chain extender (h) and (i) obtained in Production Example 2 was used instead of 0.1 mol. An aqueous dispersion of a urethane polymer was obtained when using the chain extender (i), and an aqueous dispersion of a urethane polymer when a chain extender (i) was used was obtained. Example 12 All operations were performed in the same manner as in Example 1 except that 33.6 g (0.2) mol of hexamethylene diisocyanate was used instead of 0.2 mol of tolylene diisocyanate, and an aqueous dispersion of the urethane polymer was prepared. A liquid [] was obtained. Aqueous dispersions of urethane polymers obtained in Examples 10 to 12 and Comparative Examples 7 and 8 [] to [
] and the transparency of the film formed from the aqueous dispersion are shown in Table 4 along with the acid value (calculated value) of the urethane polymer. In addition, film formation of an aqueous dispersion of urethane polymer is as follows:
This was carried out by applying the aqueous dispersion onto a glass plate and drying it.

【table】

[Table] The method for producing a water-dispersible urethane polymer of the present invention is as described above, in which a urethane prepolymer having terminal isocyanate groups is reacted with a compound having a specific structure as a chain extender. By obtaining a urethane polymer with an acid value of 20 or more, this urethane polymer is dispersed in an aqueous medium with the carboxyl groups in the polymer neutralized with an inorganic or organic alkaline substance to obtain an aqueous dispersion of the urethane polymer. The preparation operation for obtaining the liquid is easy, the water dispersibility of the urethane polymer is good, the stability of the aqueous dispersion of the urethane polymer obtained is high, and the aqueous dispersion is transparent. Reliably produces water-dispersible urethane polymers that exhibit excellent properties such as smoothness, smoothness, gloss, and mechanical strength, and also have film-forming ability, without the risk of gelation. It has the function and effect of being able to do the following.

Claims (1)

[Claims] 1. A chain extender represented by the following general formula [] is added to a urethane prepolymer having terminal isocyanate groups so that the acid value of the resulting urethane polymer is 20.
A method for producing a water-dispersible urethane polymer, which comprises reacting in the above amount. [However, in the formula, A is a divalent organic residue selected from [Formula] (R ₁ is H, COOH, or an alkyl group), [Formula], [Formula], and [Formula], and B is 3 represents a valent aliphatic residue. ] 2 The chain extender represented by the general formula [] is A method for producing a water-dispersible urethane polymer according to claim 1, which is a compound represented by: 3 The chain extender represented by the general formula [ ] has the formula A method for producing a water-dispersible urethane polymer according to claim 1, which is a compound represented by: 4 The chain extender represented by the general formula [] is the formula [formula] or the formula The method for producing a water-dispersible urethane polymer according to claim 1, which is a compound represented by: or a mixture of both of these compounds. 5 The chain extender represented by the general formula [ ] has the formula A method for producing a water-dispersible urethane polymer according to claim 1, which is a compound represented by: