JPS6314735B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin emulsion containing nitrocellulose using a novel water-dispersible urethane-modified vinyl polymer as a dispersant and a method for producing the same, which has excellent stability and The present invention also provides an aqueous emulsion solution that can form a film with excellent water resistance.

Because nitrocellulose has the property of forming films with excellent hardness, transparency, and gloss, it is used in large quantities in paints, coating agents, printing inks, etc., and most of them are organic. It is used in the form of a so-called solvent-based solution, which is dissolved in a solvent, but paints and printing inks made from these solvent-based solutions contain organic substances that can cause air pollution, deterioration of the working environment, and fire hazards when they are used. Since the use of organic solvents has disadvantages such as the release of solvent and the fact that it goes against resource conservation, one method that does not use organic solvents is to use an aqueous emulsion with nitrocellulose as a dispersoid. A method has been proposed.

By the way, nitrocellulose is difficult to emulsify in water alone and is hard and relatively brittle, so it is mixed with other resins and plasticizers and mechanically processed using an emulsifier. A method such as obtaining an emulsion containing a blend of nitrocellulose and a vinyl polymer as a dispersoid by emulsifying it in water or dissolving nitrocellulose in a vinyl monomer and emulsion polymerizing it. has been used, but the emulsion obtained by the former method is not sufficiently stable;
Moreover, the coating film obtained has the disadvantage of poor water resistance due to the presence of the emulsifier, and the latter method requires selection of a vinyl monomer that dissolves nitrocellulose, making it difficult to use. It has drawbacks such as being limited by vinyl monomers and still having negative effects due to the use of emulsifiers.

In contrast, the first invention provides a resin emulsion containing nitrocellulose that does not have the above-mentioned drawbacks, and the second invention provides a resin emulsion containing nitrocellulose according to the first invention. The object of the present invention is to provide a method for efficiently, reliably, and easily obtaining a resin emulsion containing the present invention.

The configuration of the present invention will be explained below.

The nitrocellulose-containing resin emulsion of the present invention is one in which a water-dispersible urethane-modified vinyl polymer having an ionic group and a polyurethane segment as side chains and nitrocellulose are dispersed in an aqueous medium. It is.

That is, the resin emulsion containing nitrocellulose of the present invention is a resin emulsion containing nitrocellulose as a dispersoid, and comprises nitrocellulose, an ionic group as a dispersant for nitrocellulose, and a polyurethane segment as side chains. This is an aqueous emulsion in which a water-dispersible urethane-modified vinyl polymer is dispersed in an aqueous medium consisting of water or water and a water-soluble organic solvent.

As mentioned above, the water-dispersible urethane-modified building polymer used as a dispersant in the present invention has an ionic group and a polyurethane segment as side chains, and has the property of dispersing itself in water. It is necessary that

The ionic groups in this urethane-modified vinyl polymer include anionic groups such as carboxyl groups and their salts, sulfonic acid groups and their salts, sulfuric acid groups, phosphoric acid groups and their salts, or primary, secondary, and/or anionic groups.
Alternatively, cationic groups such as tertiary basic nitrogen atom-containing groups, acid salts thereof, and quaternary ammonium bases can be used, but from the viewpoint of economic efficiency and ease of reaction, etc. The anionic group is preferably an alkali salt of a carboxylic acid, and the cationic group is preferably an acid salt of a basic tertiary nitrogen atom-containing group or a quaternized product thereof.

Further, as the polyurethane segment in this urethane-modified vinyl polymer, general polyurethane segments such as polyether polyurethane, polyester polyurethane, polyether ester polyurethane, etc. can be used, but the molecular weight is about 300 or more, especially 500 to 2000 is preferred. If the molecular weight is less than 300, the water dispersibility of the resulting urethane-modified vinyl polymer for nitrocellulose will decrease;
In the case of polymers with higher molecular weights, it is not only difficult to manufacture the urethane-modified vinyl polymer itself, but also
This is because the water dispersibility of the resulting urethane-modified vinyl polymer may be reduced.

This water-dispersible urethane-modified vinyl polymer having ionic groups and polyurethane segments as side chains generally has terminal isocyanate groups in the vinyl polymer having ionic groups and hydroxyl groups. It is obtained by reacting a urethane prepolymer and introducing a polyurethane segment into a vinyl polymer. The urethane prepolymer can be made into a vinyl polymer by selecting one that does not contain hydrogen atoms or has a slower reaction rate with isocyanate groups than the hydroxyl groups contained in the vinyl polymer. What is necessary is to react preferentially to the hydroxyl groups inside.

The preferred urethane-modified vinyl polymer used in the present invention is, specifically, the acid value obtained by reacting a vinyl polymer having a hydroxyl group and a carboxyl group with a urethane prepolymer having a terminal isocyanate group. Basic tertiary nitrogen obtained by reacting a urethane-modified vinyl polymer of 20 or more or a vinyl polymer having a hydroxyl group and a basic tertiary nitrogen atom with a urethane prepolymer having a terminal isocyanate group. A urethane-modified vinyl polymer having an atomic content of 0.4 mg equivalent/g or more is preferred because it has particularly excellent water dispersibility. These urethane-modified vinyl polymers are
A vinyl polymer having a hydroxyl group and a carboxyl group and a urethane prepolymer having a terminal isocyanate group have a dissolving effect on both the vinyl polymer and the urethane prepolymer. A urethane-modified vinyl polymer having an acid value of 20 or more is produced by heating the reaction in an organic solvent that does not show reactivity toward functional groups, or a urethane-modified vinyl polymer having a hydroxyl group and a basic tertiary nitrogen atom is produced. It has a dissolving effect on both the vinyl polymer and the urethane prepolymer having terminal isocyanate groups, but has no reactivity toward the functional groups of various polymers. The basic tertiary nitrogen atom content was 0.4mg by heating reaction in an organic solvent not shown.
It can be easily obtained by means such as producing a urethane-modified vinyl polymer having an equivalent weight/g or more. The urethane-modified vinyl polymer obtained in this way has different properties from other dispersants in that it itself has excellent film-forming ability.
When forming a resin emulsion containing nitrocellulose, even if a large amount of the urethane-modified vinyl polymer is contained as a dispersant in the resin emulsion, the film-forming ability of the resin emulsion is not reduced. It also has

In the nitrocellulose-containing resin emulsion of the present invention, the weight ratio of the water-dispersible urethane-modified vinyl polymer as a dispersant and nitrocellulose is not particularly limited; From the viewpoint of performance and the like, it is preferable to use a weight ratio of about 5 to 100 parts by weight, particularly about 10 to 50 parts by weight, of nitrocellulose per 100 parts by weight of the urethane-modified vinyl polymer.

The nitrocellulose-containing resin emulsion of the present invention is produced by uniformly dissolving the water-dispersible urethane-modified vinyl polymer and nitrocellulose in an organic solvent that has a dissolving effect on both.
Obtaining by adding an aqueous solvent to this to dissociate the ionic groups of the water-dispersible urethane-modified vinyl polymer, dispersing the polymer in this aqueous solvent, and removing the organic solvent as necessary. I can do it. In this step, in order to uniformly disperse both the water-dispersible urethane-modified vinyl polymer and nitrocellulose in the aqueous solvent, it is necessary to sufficiently dissociate the ionic groups in the urethane-modified vinyl polymer to make it hydrophilic. It is necessary to make it act effectively as a functional group. For this reason, for example, if the ionic group in the urethane-modified vinyl polymer is a carboxyl group,
In the presence of an alkaline substance approximately equivalent to neutralizing this,
Further, when the ionic group is an amino group, it is preferable to disperse the polymer in the presence of an acidic substance. Moreover, in this step, other general emulsifiers etc. can also be used together.

In addition, when a step of removing the organic solvent is provided during the manufacturing process of the resin emulsion containing nitrocellulose of the present invention, the organic solvent is removed after dispersing the urethane-modified vinyl polymer in the aqueous solvent. Of course, a removal step can be provided, but an organic solvent removal step can also be provided before dispersing the nitrocellulose and the urethane-modified vinyl polymer in the aqueous solvent.

The resin emulsion containing nitrocellulose and the method for producing the same of the present invention are constructed as described above, and the urethane-modified vinyl polymer dispersed as a dispersant in an aqueous solvent has excellent self-dispersibility. The resin emulsion has extremely excellent stability, and the polyurethane segment of the polymer is protected by a safe vinyl polymer. is water resistance, hardness,
Because it has the property of forming a film with excellent adhesive strength and other properties, it is excellent for use as a surface treatment agent for paper, a binder for water-based paints and inks, a clear coat agent, a fiber treatment agent, etc. In addition, the manufacturing method allows a resin emulsion to be obtained without using a special plasticizer or emulsifier, so that the resin emulsion, which is the object of the present invention, can be easily and reliably manufactured. It has the effect of being able to do something.

Hereinafter, the resin emulsion containing nitrocellulose of the present invention, the functions and effects of the resin emulsion, and examples of the method for producing the solution will be explained based on Examples and Comparative Examples.

Example 1 (i) Production of vinyl polymer having hydroxyl group and carboxyl group 200 g of ethyl acetate was charged into a 500 ml four-necked flask, heated and maintained at reflux temperature. While passing nitrogen gas, add 20 g of acrylic acid, 40 g of 2-hydroxylethyl acrylate, 20 g of 2-ethylhexyl acrylate, 80 g of methyl methacrylate,
206 g of a mixed monomer solution consisting of 40 g of styrene, 2 g of thioglycolic acid, and 4 g of azobisisobutyronitrile is added dropwise over 3 hours. After the dropwise addition was completed, the temperature was maintained for another 4 hours, and the vinyl polymer
391 g of an ethyl acetate solution of (A) was obtained.

The vinyl polymer (A) has an acid value of 81 and a hydroxyl value of 94.

(ii) Production of urethane prepolymer having terminal isocyanate groups In a 500 ml four-necked flask, add 100 g of ethyl acetate,
46.6 g of polyethylene glycol (molecular weight 200) was charged, and 50.7 g of tolylene diisocyanate (TDI) was added dropwise at room temperature. 40 years since the fever stopped
React for 1 hour at ~50°C, then add 2.7 mL of ethanol
g was added thereto, and the reaction was continued for an additional hour at the same temperature. Next, 0.06g of dibutyltin dilaurate was added,
After the heat generation had stopped, the reaction was carried out at 50 to 60°C for about 1 hour to obtain 200 g of an ethyl acetate solution of the urethane prepolymer (B) having terminal isocyanate groups. The reaction component ratio of this urethane prepolymer (B) is polyethylene glycol: TDI: ethanol = 4:5:
1 (molar ratio), and has an average of one terminal isocyanate group.

(iii) Production of urethane-modified vinyl polymer In a 500 ml four-necked flask, add 47.5 g of the ethyl acetate solution of the vinyl polymer (A) obtained in section (i) above and the same solution obtained in section (ii) above. Ethyl acetate solution of urethane prepolymer (B) with terminal isocyanate groups
After raising the temperature and reacting at 70-80℃ for 2 hours, 5g of ethanol was added, and then
After reacting for 30 minutes, the urethane-modified vinyl polymer (C)
An ethyl acetate solution of was obtained.

The reaction ratio of urethane prepolymer/vinyl polymer in this reaction is approximately 2/1 by weight,
The equivalent ratio of NCO/OH was about 1/1.44, and the acid value of the obtained urethane-modified vinyl polymer (C) was about 27.

(iv) Preparation of resin emulsion containing nitrocellulose Add a solution of nitrocellulose in ethyl acetate, which had been adjusted to a concentration of 30% with ethyl acetate, to the ethyl acetate solution of the urethane-modified vinyl polymer obtained in section (iii) above.
After adding 75g and stirring and mixing thoroughly, 4.5g of dimethylethanolamine and 223g of water were added.
After thorough stirring and dispersion, vacuum distillation was performed at approximately 60°C for 2 hours to remove ethyl acetate, and the product was further diluted with water to obtain a urethane-modified vinyl polymer containing nitrocellulose with a polymer concentration of 30%. A resin emulsion was obtained using an aqueous dispersion solution (PH7.3) of

The stability of the obtained resin emulsion containing nitrocellulose is very good, and the film obtained by coating this resin emulsion on a glass plate and drying it is colorless, transparent, tough, water resistant, and weather resistant. It was excellent in both sex.

Example 2 (i) Production of a vinyl polymer having a hydroxyl group and a basic tertiary nitrogen atom In the operation in item (i) of Example 1, 40 g of dimethylaminoethyl methacrylate, 2- Hydroxyethyl acrylate 40
20 g of 2-ethylhexyl acrylate, 60 g of methyl methacrylate, 40 g of styrene, 2 g of lauryl mercaptan, and 4 g of azobisisobutyronitrile. 393 g of an ethyl acetate solution of vinyl polymer (D) was obtained.

The vinyl polymer (D) has a basic tertiary nitrogen atom content of 1.24 mg equivalent/g and a hydroxyl value of 94.

(ii) Production of urethane prepolymer having terminal isocyanate groups The ethyl acetate solution of urethane prepolymer B in section (ii) of Example 1 was used.

(iii) Production of urethane-modified vinyl polymer 71.5 g of an ethyl acetate solution of the vinyl polymer (D) obtained in item (i) above and the urethane prepolymer having a terminal isocyanate group as described in item (ii) above. Using 75 g of ethyl acetate solution of (B) and 4 g of ethanol, the same operation as in section (iii) in Example 1 was performed,
An ethyl acetate solution of urethane-modified vinyl polymer (E) was obtained.

The reaction ratio of urethane prepolymer/vinyl polymer in this reaction is approximately 1/1 by weight,
The NCO/OH equivalent ratio was approximately 1/2.87, and the basic tertiary nitrogen atom content of the obtained urethane-modified vinyl polymer (E) was 0.62 mg equivalent/g.

(iv) Preparation of resin emulsion containing nitrocellulose An ethyl acetate solution of the urethane-modified vinyl polymer (E) obtained in the above (iii) and 30% ethyl acetate in advance.
Using 75 g of an ethyl acetate solution of nitrocellulose adjusted to a certain concentration, 3.7 g of 90% acetic acid, and 224 g of water, the same procedure as described in section (iv) of Example 1 was carried out to prepare nitrocellulose with a polymer concentration of 30%. An aqueous dispersion solution (PH
A resin emulsion according to 3.3) was obtained.

The stability of the obtained resin emulsion containing nitrocellulose is very good, and the film obtained by coating this resin emulsion on a glass plate and drying it is colorless, transparent, tough, water resistant, and weather resistant. It was excellent in both sex.

Example 3 Resin emulsion obtained in section (iv) of Example 2
Add 1.3g of epichlorohydrin to 100g and heat at 60℃
The mixture was reacted for 3 hours to quaternize the basic tertiary nitrogen atom. The resulting resin emulsion containing nitrocellulose had a nonvolatile content of 30.9% and a pH of 4.0.
Both stability and film-forming properties were excellent.

Comparative Example 1 (i) Production of a vinyl polymer having a hydroxyl group and a carboxyl group The ethyl acetate solution of the vinyl polymer (A) in section (i) of Example 1 was used.

(ii) Preparation of resin emulsion containing nitrocellulose Ethyl acetate solution of vinyl polymer (A) of item (i) above
142.4 g, 75 g of 30% nitrocellulose ethyl acetate solution, 10.8 g of dimethylethanolamine, water
A resin emulsion with an aqueous dispersion solution (PH 7.8) of a vinyl polymer containing nitrocellulose with a polymer concentration of 30% was prepared by using 217 g and operating in the same manner as described in section (iv) of Example 1. I got it.

After leaving the obtained aqueous dispersion of resin emulsion containing nitrocellulose for 24 hours, we observed its stability. As a result, a large amount of precipitated substances were generated in the dispersion, and the stability of the dispersion was determined. It turned out to be bad. Further, the film obtained by applying this dispersion solution onto a glass plate and drying it was cloudy.

Comparative Example 2 (i) Production of a vinyl polymer having a hydroxyl group and a basic tertiary nitrogen atom The ethyl acetate solution of the vinyl polymer (D) in section (i) of Example 2 is used.

(ii) Preparation of resin emulsion containing nitrocellulose Ethyl acetate solution of the vinyl polymer (D) of item (i) above
143 g of nitrocellulose, 75 g of 30% concentration ethyl acetate solution, 7.4 g of 90% acetic acid, and 220 g of water were operated in the same manner as described in section (iv) of Example 1 to obtain a vinyl-based material containing nitrocellulose. A resin emulsion was obtained using an aqueous dispersion solution (PH3.1) of a polymer.

The stability of the obtained aqueous dispersion of resin emulsion containing nitrocellulose was observed after it was left for 24 hours. As a result, a large amount of precipitated substances were generated in the dispersion, and its stability was poor. It has been found. Further, the film obtained by applying this dispersion solution onto a glass plate and drying it was cloudy.

Claims (1)

[Scope of Claims] 1. A nitrocellulose, characterized in that a water-dispersible urethane-modified vinyl polymer having an ionic group and a polyurethane segment as side chains and nitrocellulose are dispersed in an aqueous medium. Resin emulsion containing cellulose. 2. The resin emulsion containing nitrocellulose according to claim 1, wherein the ionic group is a carboxyl group or a salt thereof. 3. The nitrocellulose-containing resin emulsion according to claim 2, wherein the water-dispersible urethane-modified vinyl polymer has an acid value of 20 or more. 4. The nitrocellulose-containing resin emulsion according to claim 1, wherein the ionic group is a basic tertiary nitrogen atom-containing group or a quaternary ammonium base. 5 Water dispersible urethane modified vinyl polymer is 0.4
The resin emulsion containing nitrocellulose according to claim 1, which has basic tertiary nitrogen atoms of mg equivalent/g or more. 6 A water-dispersible urethane-modified vinyl polymer having an ionic group and a polyurethane segment as side chains and nitrocellulose are uniformly dissolved in an organic solvent that has the property of dissolving both, and an aqueous solvent is added to this. A nitrocellulose containing nitrocellulose is added, and further the ionic groups of the water-dispersible urethane-modified vinyl polymer are dissociated, the polymer is dispersed in this aqueous solvent, and the organic solvent is removed if necessary. A method for producing a resin emulsion.