JPH07157526A - Production of self-emulsifiable urethane emulsion - Google Patents

Abstract

PURPOSE:To obtain a self-emulsifiable urethane emulsion containing a polyure thane having a rosin skeleton in the molecule as a resin component, excellent in pigment dispersibility, having excellent adhesivity and water resistance to hydrophobically surfaced base materials, and useful as a coating agent, etc. CONSTITUTION:This emulsion is obtained by neutralizing a urethane propolymer having carboxyl group and unreacted isocyanate produced by reaction among (1) a polyol containing >=5wt.% of a polyol having a rosin skeleton in the molecule (e.g. a reactional product from one molecule of a diepoxy compound and two molecules of rosin), (2) a polyisocyanate (e.g. 2,4-tolylene diisocyanate) and (3) an acid diol (e.g. 2,2-dimethylolpropionic acid), followed by emulsification in an aqueous medium and then crosslinking reaction (or vice versa).

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 self-emulsifying urethane emulsion having a resin component of polyurethane having a rosin skeleton in the molecule, and the emulsion obtained according to the present invention has a pigment dispersibility Excellent, the coating film has excellent adhesion to polypropylene, polyethylene, etc., which have a hydrophobic surface, and excellent water resistance, and can be used as a coating agent or printing ink. Is.

[0002]

2. Description of the Related Art In recent years, various plastic base materials for packaging materials have been developed due to diversification of objects to be packaged and diversification of packaging technology. These packaging materials are usually coated or printed for printing or surface protection, but various performances such as adhesion to various plastic substrates have been required. There are organic solvent-based and water-based coating agents or printing inks (hereinafter simply referred to as coating agents) for plastic base materials for packaging materials. As the organic solvent-based coating agent, a polyurethane having a rosin skeleton obtained by reacting a polyol, a polyol obtained by reacting a diepoxy compound with two molecules of rosin, a polyisocyanate and a chain extender (Japanese Patent Laid-Open No. 5-15972) Etc. have been proposed. A coating film obtained from the polyurethane has improved adhesion to polyethylene, polypropylene film and the like having a hydrophobic surface due to the influence of a rosin skeleton, but the polyurethane having a rosin skeleton in the above-mentioned prior art contains 50% by weight or more of an organic solvent. Since it is contained, there is a problem that the organic solvent adversely affects the human body and the environment. Therefore, in place of the organic solvent-based coating agent, such a water-based coating agent that is less likely to cause such an adverse effect is being used.

[0003]

As the water-based coating agent, for example, an acrylic resin emulsion is used for top coating agents, paints and the like because of its excellent weather resistance. However, acrylic resin emulsions are not sufficient in abrasion resistance and blocking resistance, and have poor water resistance and adhesion to polyethylene, polypropylene film, etc. having a hydrophobic surface, and are used for applications requiring such physical properties. There is a problem of difficulty. A self-emulsifying urethane emulsion synthesized without using a surfactant is known as a solution to the drawbacks of the acrylic resin emulsion. However, the conventional self-emulsifying urethane emulsion has a problem that it is not sufficiently adherent to polyethylene, polypropylene film and the like having a hydrophobic surface, and it is difficult to use it in applications requiring these physical properties.

As another method for producing an aqueous coating agent, which improves the drawbacks of the conventional aqueous coating agent, (1) a rosin ester resin, a hydrocarbon resin or a polyamide resin is added in water by using a surfactant. A method of mixing a stabilized emulsion and a urethane emulsion (JP-A-3-7783) and (2) a method of mixing an olefin resin and a urethane emulsion (JP-A-3-783).
No. 124779) has been proposed. However,
The aqueous coating agent obtained by the production method (1) improves the adhesion to polyethylene, polypropylene film, etc. having a hydrophobic surface to some extent under the influence of the rosin ester resin, etc., but stabilizes the rosin ester in water. Since a surfactant is used to disperse, the water resistance and solvent resistance are reduced, and the transparency of the coating film is reduced because the surfactant migrates to the coating surface over time, and Has a problem that the adhesiveness to the base material also decreases, and it cannot be said to be sufficient when considering its use as a coating agent. In addition, the aqueous coating agent obtained by the above-mentioned production method (2) stores emulsions although the adhesion to polyethylene, polypropylene film, etc. is slightly improved due to the influence of olefinic resin such as chlorinated polypropylene. If this is done, there is a problem of storage stability in that the resin will precipitate, and a surfactant is used to solve this problem. However, when a surfactant is used, the same as in the production method of (1) above. Problems such as deterioration of water resistance and solvent resistance and deterioration of transparency of the film will occur. The present inventors have solved the above problems that conventional coating agents have, polypropylene having a hydrophobic surface, excellent adhesion to various plastic substrates such as polyethylene, water resistance, The inventors conducted extensive studies to find a method for producing a urethane emulsion having excellent solvent resistance and storage stability.

The present invention solves the problems as described above and, when used as a coating agent, provides excellent adhesion, water resistance and solvent resistance to various plastic substrates having a hydrophobic surface such as polypropylene and polyethylene. It is an object of the present invention to provide a novel aqueous coating composition having the above and having excellent pigment dispersibility.

[0006]

The present invention provides a carboxyl group and an unreacted isocyanate group obtained by reacting a polyol containing 5 wt% or more of a polyol having a rosin skeleton in the molecule, a polyisocyanate and an acid diol. The neutralized urethane prepolymer is neutralized, and then the neutralized urethane prepolymer is emulsified or emulsified in an aqueous medium, and then the neutralized urethane prepolymer is crosslinked, or the neutralized urethane prepolymer is crosslinked. The present invention relates to a method for producing a self-emulsifying urethane emulsion, which comprises emulsifying a crosslinked polyurethane in an aqueous medium after the reaction. Hereinafter, the present invention will be described in detail.

Urethane Prepolymer Having Carboxyl Group and Unreacted Isocyanate Group Urethane prepolymer having carboxyl group and unreacted isocyanate group (hereinafter simply referred to as urethane prepolymer) used in the method for producing the self-emulsifying urethane emulsion of the present invention. Is obtained by the reaction of the following polyol, polyisocyanate and acid diol.

Polyol In the present invention, a polyol containing 5% by weight or more of a polyol having a rosin skeleton in its molecule is used. If the proportion of the polyol is less than 5% by weight, the resulting emulsion film will be inferior in adhesion to the substrate, water resistance and the like.

As the polyol having a rosin skeleton,
Various compounds can be used, and examples thereof include a reaction product of one molecule of various known diepoxy compounds and two molecules of rosin.
In this case, as the diepoxy compound, for example, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether. Acyclic aliphatic diglycidyl ethers such as glycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether and 1,6-hexanediol diglycidyl ether, 2,2-bis (4-hydroxyphenyl) propane diglycidyl ether , Bis (4-hydroxyphenyl) methane diglycidyl ether, 1,1
-Bis (4-hydroxyphenyl) ethane diglycidyl ether, 2,2-bis (4-hydroxycyclohexyl) propane diglycidyl ether, 3,3 ', 5
5'-tetramethyl-4,4'-dihydroxybiphenyl diglycidyl ether and 2,2'-bis (4- (β
-Hydroxypropoxy) phenyl) propane diglycidyl ether or other aromatic or alicyclic diglycidyl ether, 3,4-epoxycyclohexylmethyl, 3,4-
Examples thereof include cycloaliphatic cyclic oxiranes such as epoxycyclohexanecarboxylate and vinylcyclohexene dioxide. Examples of the rosin include gum rosin, tall oil rosin, wood rosin, and rosin derivatives such as hydrogenated products, disproportionated products and polymers obtained from these. The polyol having a rosin skeleton preferably has a number average molecular weight of 700 to 10,000, more preferably 700 to 5,000. When a number average molecular weight of less than 700 is used, the resulting film tends to have poor flexibility, whereas when a number average molecular weight of more than 10,000 is used, blocking resistance tends to be poor. There is a possibility that it will not show sufficient performance when considered as.

As the polyol which can be used together with the polyol having a rosin skeleton in the molecule, various conventionally known polyols can be used. Specifically, ethylene glycol, diethylene glycol, triethylene glycol, 1,2- Low molecular weight glycols such as propylene glycol, trimethylene glycol, 1,3-butylene glycol, tetramethylene glycol, hexamethylene glycol, hydrogenated bisphenol A and ethylene oxide or propylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, poly Polyether polyols such as tetramethylene glycol, ethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol and silane. Obtained by dehydration reaction of polyhydric alcohol such as lohexyldimethanol and polyvalent carboxylic acid such as maleic acid, succinic acid, adipic acid and phthalic acid, or by ring-opening polymerization reaction of cyclic ester such as caprolactone Examples thereof include polyester polyols and polycarbonate polyols such as polycarbonate diols.

Polyisocyanate As the polyisocyanate, various conventionally known compounds can be used, and specifically, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4 '. -Aromatic diisocyanates such as diphenylmethane diisocyanate and m-phenylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 1,4 cyclohexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and aliphatic diisocyanates such as isophorone diisocyanate. .

As the acid diol, various conventionally known acid diols can be used. Specifically, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid and 2,2-dimethylol can be used. Examples include valeric acid.

Manufacturing method As a method of manufacturing the urethane prepolymer, there is, for example, a method of reacting a polyol having a rosin skeleton in the molecule or this with another polyol, polyisocyanate and acid diol to form a urethane, There is also a method in which polyisocyanate is first reacted to urethanize, and then the reaction product is reacted with an acid diol to further urethanize, and the latter method is preferable in the present invention in that there are few side reactions. The urethane prepolymer obtained by the latter method theoretically has unreacted isocyanate groups at both ends. Each urethanization reaction was carried out without a solvent or in an organic solvent in the presence or absence of a catalyst at a reaction temperature of 40 to 100 with stirring.
It can be easily performed by heating at ℃ for 2 to 8 hours.

When an organic solvent is used in the urethanization reaction, it is preferable to use a water-soluble organic solvent because it can dissolve the acid diol. Specific examples include acetone and N-methyl-2-pyrrolidone. , Dimethylformamide, methyl ethyl ketone, and the like. In this case, the solvent having active hydrogen such as a hydroxyl group and a carboxyl group reacts with the isocyanate group, so that a solvent having no active hydrogen is preferable.

Examples of the catalyst that can be used in the urethanization reaction include triethylenediamine, triethylamine,
Tertiary amines such as N-methylmorpholine, N, N, N ', N'-tetramethyl-propylenediamine, 1,8-
Amidines such as diazabicyclo (5,4,0) -undecene-7, tin compounds such as tin octenoate and dibutyltin laurate, or Ti, Na, K, V, Fe, M
Examples thereof include metal salts such as n and Pb. The amount of catalyst added is
0.0001 to 0 .. per 100 parts of the total amount of each raw material.
001 parts is preferred.

A preferable reaction ratio between the polyol having a rosin skeleton in the molecule or the other polyol and the acid diol (hereinafter referred to as a polyol mixture) and the polyisocyanate is a molar ratio of the hydroxyl group in the polyol mixture and the isocyanate group in the polyisocyanate. In terms of the ratio, the ratio is an excess of isocyanate groups, and the ratio of hydroxyl groups is preferably 0.4 to 0.99 mol per 1.0 mol of isocyanate groups, and more preferably 0.5 to 0.7 mol. . When the proportion of hydroxyl groups is less than 0.4 mol,
The proportion of unreacted polyisocyanate increases,
On the other hand, if it exceeds 0.99 mol, the molecular weight becomes too large, or the proportion of unreacted isocyanate groups in the urethane prepolymer becomes low.

The combined proportion of the acid diol is preferably 2 to 15% by weight of the urethane prepolymer finally obtained. If the proportion of the acid diol is less than 2% by weight, the obtained emulsion may become unstable in water, while if it exceeds 15% by weight, the hydrophilicity of the urethane prepolymer obtained is high. May gel too much.

The urethane prepolymer can be obtained in a solvent-free state or as an organic solvent solution, but the solvent-free urethane prepolymer can be used before the subsequent neutralization reaction. It is preferably dissolved in a water-soluble organic solvent such as pyrrolidone, dimethylformamide, and methyl ethyl ketone.

Method for Producing Urethane Emulsion The method for producing the self-emulsifying urethane emulsion of the present invention comprises the step of adding a neutralizing agent to the urethane prepolymer, preferably a solution of the urethane prepolymer in an organic solvent. After neutralizing the carboxyl groups of the above, and then while emulsifying or emulsifying the neutralized urethane prepolymer in an aqueous medium, the isocyanate group in the neutralized urethane prepolymer is reacted with a chain extender to carry out a crosslinking reaction. The method is to carry out, or a method of emulsifying the crosslinked polyurethane in an aqueous medium after the crosslinking reaction of the neutralized urethane prepolymer. The emulsification is carried out by stirring the neutralized urethane prepolymer or crosslinked polyurethane in an aqueous medium.
The stirring at that time may be performed according to a conventional method.

The neutralizing agent that can be used in the neutralization includes
Examples thereof include tertiary amines such as ammonia, trimethylamine, triethylamine, tripropylamine, tributylamine and triethanolamine, and alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. In the present invention, among these, the physical properties of the film formed by the emulsion from which the tertiary amine is obtained are not adversely affected, which is preferable. As a method for adding the neutralizing agent, the neutralizing agent is added to the urethane prepolymer directly or as an aqueous solution.
In the present invention, it is preferable to add the neutralizing agent directly to the urethane prepolymer, because a stable emulsion can be formed. The amount of the neutralizing agent added is
The equivalent of 0.5 to 2.5 times the amount of carboxyl groups in the urethane prepolymer is preferred. If the amount of the neutralizing agent added is less than 0.5 times the equivalent, a stable emulsion may not be obtained. It may adversely affect the physical properties.

After the above urethane prepolymer is neutralized, water is added to the neutralized urethane prepolymer with stirring to form an emulsion, and a chain extender is added to this to carry out a crosslinking reaction.
Alternatively, an aqueous solution of a chain extender is added to the neutralized urethane prepolymer with stirring to emulsify and simultaneously crosslink the neutralized prepolymer, or a chain extender is added to the neutralized prepolymer with stirring to neutralize the urethane. Crosslink the prepolymer,
Water is added to the obtained crosslinked polyurethane with stirring to form an emulsion. Due to the crosslinking reaction, the molecular weight of the urethane prepolymer increases, and properties such as solvent resistance can be exhibited. As the chain extender, an amine chain extender having a higher reactivity with isocyanate groups in the neutralized prepolymer than water is preferable, and specifically, a polyfunctional amine is preferable.

As the polyfunctional amine, various conventionally known compounds can be used, and examples thereof include ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, cyclohexylenediamine, phenylenediamine and toluenediamine. .

The amount of the chain extender used is preferably 0.01 to 0.4 mol with respect to 1 mol of the isocyanate group in the polyisocyanate used for producing the urethane prepolymer. If the amount of the chain extender used is less than 0.01 mol, sufficient physical properties of the film may not be obtained when it is used as a coating agent or an ink. The molecular weight may be too high and the resulting emulsion may be unstable.

The amount of water in the emulsion is such that the solid content of the self-emulsifying urethane emulsion as the final product is 30 to 30.
An amount of about 55% by weight is preferable.

O Method of Use The self-emulsifying urethane emulsion obtained by the present invention can be used as it is, or can be used by removing the organic solvent under reduced pressure, if necessary. When a water-soluble organic solvent having a relatively high boiling point such as dimethylformamide and N-methyl-2-pyrrolidone is used as the organic solvent, it is desirable to use the organic solvent in a state of containing it.

The self-emulsifying urethane emulsion obtained by the present invention contains, if necessary, pigments, dyes, thickeners, leveling agents, heat stabilizers, UV absorbers, antioxidants, organic solvents, defoaming agents. It is possible to mix
Further, a surfactant may be blended within a range that does not adversely affect the obtained coating film. The self-emulsifying urethane emulsion obtained by the present invention can be used in coating agents, paints, printing inks and the like,
In particular, it can be suitably used as a printing ink.
Further, the emulsion can be used for various base materials such as cloth, leather, paper, wood, metal and plastic, and particularly various kinds of polypropylene, polyethylene, polyester, nylon and the like having a hydrophobic surface. It can be suitably used for a plastic substrate.

[0027]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples below. Example 1 A reactor equipped with a reflux condenser, a thermometer, and a stirrer was attached to a reactor having a rosin skeleton in the molecule and having a molecular weight of 1000 [KE-601 manufactured by Arakawa Chemical Industry Co., Ltd.] 40.
0 g (0.040 mol), molecular weight 2000 polypropylene glycol 94.0 g (0.047 mol), isophorone diisocyanate 53.9 g (0.243 mo)
1), 0.0002 g of dibutyltin laurylate and 100 g of methyl ethyl ketone were added, and a urethanization reaction was carried out at 80 ° C. for 2 hours to produce a prepolymer. In this reaction liquid, 10 g of dimethylolpropionic acid (0.075 m
ol) was added, and the reaction was further performed at 80 ° C. for 5 hours. Next, triethylamine (0.075 mol) was added to the urethane prepolymer for neutralization, and then an aqueous solution of diethylenetriamine (0.022 mol) dissolved in distilled water (460 g) was added to carry out a crosslinking reaction. After the reaction
When methyl ethyl ketone was removed under reduced pressure, a self-emulsifying urethane emulsion having a resin solid content concentration of 35% and a viscosity of 100 cps / 25 ° C. was obtained.

Example 2 64.0 g (0.064 mol) of a polyol having a rosin skeleton in the same molecule as in Example 1 and 68.0 g (0.032 mo) of a polycarbonate diol having a molecular weight of 2000.
l), 55.9 g of isophorone diisocyanate (0.2
52 mol) and dimethylolpropionic acid 15.9 g
A urethane prepolymer was prepared by carrying out the reaction in the same manner as in Example 1 except that (0.119 mol) was used. Then, 0.119 mol of triethylamine as a neutralizing agent
And 0.008m of diethylenetriamine as a chain extender
When the urethane prepolymer was neutralized, cross-linked and methyl ethyl ketone was removed in the same manner as in Example 1 except that ol was used, the resin solid content concentration was 40% and the viscosity was 35 cps /
A self-emulsifying urethane emulsion at 25 ° C was obtained.

Example 3 8.0 g of a polyol having a rosin skeleton in the molecule and having a molecular weight of 2000 [KE-615 manufactured by Arakawa Chemical Industry Co., Ltd.]
(0.008 mol), 136 g (0.068 mol) of the same polycarbonate diol as in Example 2, 53.9 g (0.243 mol) of isophorone diisocyanate, and 13 g (0.099mo) of dimethylolpropionic acid.
A urethane prepolymer was prepared by carrying out the reaction in the same manner as in Example 1 except that 1) was used. Next, the same procedure as in Example 1 was carried out except that 0.099 mol of triethylamine was used as a neutralizing agent and 0.023 mol of diethylenetriamine was used as a chain extender. A self-emulsifying urethane emulsion having a resin solid content concentration of 38% and a viscosity of 50 cps / 25 ° C. was obtained.

Example 4 63.0 g (0.063 mol) of a polyol having a rosin skeleton in the same molecule as in Example 1 and 63.0 g (0.021 mol) of polypropylene glycol having a molecular weight of 3000.
l), 58.8 g of isophorone diisocyanate (0.2
65 mol) and dimethylolpropionic acid 15.9 g
A urethane prepolymer was prepared by carrying out the reaction in the same manner as in Example 1 except that (0.119 mol) was used. Then, 0.119 mol of triethylamine as a neutralizing agent
And diethylenetriamine as chain extender 0.032m
The urethane prepolymer was neutralized, cross-linked and methyl ethyl ketone was removed in the same manner as in Example 1 except that the resin solid content concentration was 35% and the viscosity was 20 cp.
A s / 25 ° C. self-emulsifying urethane emulsion was obtained.

Example 5 75.0 g (0.075 mol) of a polyol having a rosin skeleton in the same molecule as in Example 2, 40.8 g (0.184 mol) of isophorone diisocyanate and 10 g (0.075 mol) of dimethylolpropionic acid were added. Reactions were carried out in the same manner as in Example 1 except that the urethane prepolymer was prepared. Then, Example 1 was repeated except that 0.075 mol of triethylamine was used as a neutralizing agent and 0.006 mol of diethylenetriamine was used as a chain extender.
When the above urethane prepolymer was neutralized, cross-linked and methyl ethyl ketone was removed in the same manner as above, a self-emulsifying urethane emulsion having a resin solid content concentration of 35% and a viscosity of 30 cps / 25 ° C. was obtained.

Example 6 35.0 g (0.035 mol) of a polyol having a rosin skeleton in the same molecule as in Example 1 and 34.0 g (0.017 mo) of the same polypropylene glycol as in Example 1
l), 22.4 g of toluene diisocyanate (0.12
9 mol) and dimethylolpropionic acid 8.0 g
A urethane prepolymer was prepared by carrying out the reaction in the same manner as in Example 1 except that (0.060 mol) was used. Then, 0.060 mol of triethylamine as a neutralizing agent
And 0.004m of diethylenetriamine as a chain extender
was carried out in the same manner as in Example 1 except that the urethane prepolymer was neutralized, crosslinked and methyl ethyl ketone was removed, the resin solid content concentration was 35% and the viscosity was 120 c.
A ps / 25 ° C. self-emulsifying urethane emulsion was obtained.

Comparative Example 1 In the same reactor as in Example 1, 138 g (0.069 mol) of the same polycarbonate diol as in Example 2 and 50.0 g (0.225 mo) of isophorone diisocyanate were used.
1), 0.0002 g of dibutyltin laurylate and 100 g of methyl ethyl ketone were added, and a urethanization reaction was carried out at 80 ° C. for 2 hours to produce a prepolymer. To this reaction solution was further added 12 g of dimethylolpropionic acid (0.0
90 mol) was added, and the reaction was further performed at 80 ° C. for 5 hours. Next, triethylamine (0.090 mol) was added to the urethane prepolymer for neutralization, and then an aqueous solution of diethylenetriamine (0.014 mol) dissolved in 460 g of distilled water was added to carry out a crosslinking reaction. After the reaction
When methyl ethyl ketone was removed under reduced pressure, a self-emulsifying urethane emulsion having a resin solid content concentration of 40% and a viscosity of 200 cps / 25 ° C. was obtained. (Hereinafter referred to as urethane emulsion A)

Comparative Example 2 Urethane emulsion A and rosin emulsion [HIMAX RE-210 resin solid content 60% manufactured by Toho Chemical Industry Co., Ltd.] were added and stirred at a resin ratio of 80:20 (weight ratio). Resin solid content 42.9%, viscosity 40
A milky white emulsion of 0 cps / 25 ° C was obtained.

Comparative Example 3 A urethane emulsion A and a hydrocarbon emulsion [Myogo Sangyo Co., Ltd. MGF-A-100 resin solid content 60%) were added and stirred at a resin ratio of 80:20 (weight ratio). However, resin solid content 42.9%, viscosity 250c
A milky white emulsion of ps / 25 ° C was obtained.

Performance Evaluation The urethane emulsions obtained in Examples 1 to 5 and Comparative Examples 1 to 3 were used as printing binders to evaluate the respective resin performances. (Ink composition) 40 parts by weight of titanium oxide (rutile type) 15 parts by weight of urethane emulsions obtained in Examples 1 to 5 and Comparative Examples 1 to 3 (solid content) 10 parts by weight of isopropyl alcohol To this, 35 parts of water was added, and each was kneaded with a paint conditioner to prepare a white printing ink. Thereafter, using Barcoter No. 10, a discharge-treated surface (hereinafter abbreviated as OPP) of a corona discharge-treated stretched polypropylene film having a thickness of 20 μm, and a thickness of 15 μm
m polyethylene terephthalate (PET) was printed on one side and dried at 40 ° C. to obtain a printed film.

(Evaluation of Pigment Dispersibility) The pigment dispersibility was evaluated by the viscosity of the printing ink obtained by the above formulation. ◯: Viscosity 100 cps or less (25 ° C.) Δ: Viscosity 100 to 500 cps (25 ° C.) ×: Viscosity 500 cps or more (25 ° C.) Evaluation results are shown in Table 1.

(Evaluation of Adhesiveness) A paper tape was attached to the printing surface of the printing film after being dried and left to stand for 1 day, and the following evaluation was carried out according to the state when the paper tape was rapidly peeled off. ◎: 100% printed film remained ○: 50% or more printed film remained △: Less than 50% printed film remained ×: 100% printed film did not remain Table 1 and Table 1 It shows in Table 2.

(Evaluation of Rubbing Resistance and Rubbing Resistance When Wet) The printing film after being dried and allowed to stand for 1 day, and after dipping the printing film in water at 20 ° C. for 30 minutes, a rubbing resistance tester was used. , Load 1 kg, speed 25 times / min, 50
The rubbing resistance test was performed and the following evaluations were performed. ◎: 100% printed film remained ○: 50% or more printed film remained △: Less than 50% printed film remained ×: 100% printed film did not remain Table 1 and Table 1 It shows in Table 2.

(Evaluation of solvent resistance of film) Examples 1 to 5
The urethane emulsions obtained in Comparative Examples 1 to 3 were applied to one side of OPP using Barcoter No. 10 and dried at 80 ° C. for 10 minutes to obtain samples. A cloth impregnated with toluene was rubbed on this sample 10 times, a rubbing test was performed, and the degree of peeling of the coating film was visually evaluated. ◯: There is no abnormality in the coating film Δ: The coating film dissolves. X: The coating film is completely dissolved and OPP is exposed. The results are shown in Table 1.

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

The self-emulsifying urethane emulsion having a rosin skeleton in the molecule obtained by the present invention has excellent pigment dispersibility when used as a coating agent or printing ink, and its coating film has a hydrophobic surface. It also has excellent adhesion to its own plastic substrates such as polypropylene and polyethylene, and also has excellent water resistance and solvent resistance.

Front page continuation (72) Inventor Masao Nitta 1 Toago Synthetic Chemical Industry Co., Ltd. Nagoya Research Institute, 1 Funami-cho, Minato-ku, Nagoya, Aichi

Claims (1)

[Claims] 1. A urethane prepolymer having a carboxyl group and an unreacted isocyanate group, which is obtained by reacting a polyol containing a rosin skeleton in the molecule in an amount of 5% by weight or more, a polyisocyanate and an acid diol, is neutralized. Then, while emulsifying the neutralized urethane prepolymer in an aqueous medium or after emulsifying, perform a crosslinking reaction of the neutralized urethane prepolymer, or, after the crosslinking reaction of the neutralized urethane prepolymer, convert the crosslinked polyurethane into an aqueous medium. A method for producing a self-emulsifying urethane emulsion, which comprises emulsifying in a medium.