JPH0812736A - Aqueous polyurethane resin dispersion - Google Patents

Abstract

PURPOSE:To obtain an aqueous polyurethane resin dispersion excellent in redispersibility ad storage stability by dispersing in an aq. medium a specific graft polymer obtd. by grafting a free-radical-polymerizable hydrophilic inonomer onto a polyurethane resin. CONSTITUTION:A graft polymer obtd. by grafting a free-radical-polymerizable hydrophilic monomer onto a polyurethane resin formed from a polyester polyol is dispersed in water or its mixture with a water-sol. org. solvent, giving the objective dispersion. The graft polymer is dispersed as fine particles having an average particle size of 500nm or lower, and the particles give a <13>C NMR spectrum wherein the half value width of the signal of carbonyl carbon atoms of the polyester polyol is 300Hz or higher. The resulting dispersion is excellent in redispersibility, gives a coating resin compsn. capable of forming a coating film excellent in appearance, processibility, and water resistance on a metal or plastic surface, and is useful for a coating material, an ink, an adhesive, etc.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an aqueous dispersion of a polyurethane resin containing a polyester polyol as a constituent and a method for producing the same. More specifically, it is an aqueous dispersion of a polyurethane resin having a fine particle size excellent in redispersibility and excellent in storage stability, and is used as a vehicle for paints, inks, coating agents, adhesives, etc., or fibers. , A polyurethane resin-based aqueous dispersion containing a copolymerized polyester polyol useful as a processing agent for films, paper products and the like.

[0002]

Polyurethane resins are used in the above-mentioned fields of application.
In the field where particularly excellent flexibility and adhesion to various substrates are required, its usefulness has been recognized and it has been used, but most of them are used in the form of being dissolved in a solvent. It is the actual situation. A method of using a hydrophilic group-containing diol is known as a method for making a polyurethane resin water-based, but a polyurethane-based water dispersion obtained by this method has poor redispersibility as a coating property, poor water resistance of a coating film, and the like. There is a drawback of. An aqueous method by graft-modifying a polyurethane resin is already known. For example, as a technique for graft-modifying hydrophilic polyurethane in an aqueous medium,
JP-B-60-42809, JP-A-59-138212, JP-A-64-294
No. 71 is known, and a polyurethane resin-based water dispersion is obtained, but it has drawbacks such as poor water resistance of the coating film. Techniques for graft-modifying a hydrophobic polyurethane resin to make it water-based include JP-A-5-501124, JP-A-5-186543, JP-A-54-39488, and JP-A-54-36394. However, both have drawbacks such as low graft reaction point amount and poor stability of the aqueous dispersion.

[0003]

SUMMARY OF THE INVENTION Accordingly, the present inventors
1) Does not contain externally added emulsifier, and is in water or an aqueous medium with a sufficiently reduced organic solvent content 2) Has a fine particle size with excellent redispersibility and forms a stable aqueous dispersion even at high solids concentration In addition to 3), it provides a graft-modified resin that suppresses gelation due to a crosslinking reaction at an extremely high level that maintains the high processability and substrate adhesion of polyurethane resin containing raw material polyester polyol. The purpose is to do.

[0004]

Means for Solving the Problems That is, according to the present invention, a polyurethane resin containing a polyester polyol as a constituent is graft-polymerized with a radical-polymerizable monomer containing a hydrophilic radical-containing radical-polymerizable monomer. The combined polymer is a polyurethane resin-based water dispersion dispersed in water or a mixed solvent of water and a water-soluble organic solvent, wherein the graft polymer is dispersed in fine particles having an average particle diameter of 500 nm or less. A polyurethane resin-based water dispersion in which the full width at half maximum of the carbon signal of the carbonyl group of the copolyester polyol in the ¹³ C-NMR spectrum of the fine particles is 300 Hz or more.

In order to improve the dispersion stability, the graft reaction site amount is increased to increase the graft efficiency, but at the same time, the possibility of gelation due to the crosslinking reaction is increased in the production. In the present invention, by suppressing gelation by selecting a reaction solvent, a radically polymerizable monomer, etc., it is possible to obtain a polyurethane-based water dispersion having high grafting efficiency and excellent dispersion stability.

The polyurethane resin-based aqueous dispersion containing the copolymerized polyester polyol of the present invention has a high content in an aqueous medium without using an emulsifier, because 1) the graft polymerization reaction product has a self-emulsifying property. Disperses with a fine particle size and stably. 2) The film formed by drying at room temperature or by natural drying exhibits redispersibility that can be redispersed in water or an aqueous dispersion-containing liquid. Therefore, when used as a coating agent, paint, ink, etc., it is possible to form a coating film that has excellent adhesion to a substrate and that has water resistance, solvent resistance, processability, smoothness, etc. It is possible to exert various characteristics such as.

(Copolymerized Polyester Polyol) The polyester polyol, which is a constituent component of the polyutane resin in the present invention, does not disperse or dissolve in water by itself, has hydroxyl groups at both ends, and has a molecular weight of 500.
It is from 1 to 10,000. The preferable polymerization composition is such that the dicarboxylic acid component is 60 to 99 mol% of an aromatic dicarboxylic acid, 0 to 40 mol% of an aliphatic and / or alicyclic dicarboxylic acid,
Dicarboxylic acid having a polymerizable unsaturated double bond, 0.5 to
It is 10 mol%. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid and the like, and 5-sodium sulfoisophthalic acid can also be used if necessary. Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid, and the like, and as the alicyclic dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1, 3-cyclohexanedicarboxylic acid, 1,
Examples thereof include 2-cyclohexanedicarboxylic acid and its acid anhydride. Furthermore, p-hydroxybenzoic acid, p-
(2-Hydroxyethoxy) benzoic acid, or hydroxycarboxylic acids such as hydroxypivalic acid, γ-butyrolactone and ε-caprolactone can be used if necessary.

The aromatic dicarboxylic acid as the dicarboxylic acid component is more preferably 70 to 98 mol%, and the aliphatic dicarboxylic acid and / or alicyclic dicarboxylic acid is more preferably 0 to 30 mol%. 60 aromatic dicarboxylic acids
When it is less than mol%, the workability of the coating film and the blister resistance and blister resistance of the coating film after the retort treatment tend to decrease. Further, when the aliphatic dicarboxylic acid and / or the alicyclic dicarboxylic acid exceeds 40 mol%, the hardness, stain resistance and retort resistance tend to decrease, and the aliphatic ester bond is more resistant to hydrolysis than the aromatic ester bond. Due to its low degradability,
Problems such as a decrease in the degree of polymerization of polyester may occur during storage of the aqueous dispersion or its coating composition.

Examples of the dicarboxylic acid having a polymerizable unsaturated double bond include α, β-unsaturated dicarboxylic acids such as fumaric acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid and fats having an unsaturated double bond. Examples of the cyclic dicarboxylic acid include 2,5-norbornanedicarboxylic acid anhydride and tetrahydrophthalic anhydride. The most preferred of these are fumaric acid, maleic acid and 2,5-norbornene dicarboxylic acid (endo-bicyclo
-(2,2,1) -5-heptene-2,3-dicarboxylic acid).

As means for introducing a polymerizable unsaturated double bond into the polyester polyol, any of copolymerizing a polycarboxylic acid or a polyol having a polymerizable unsaturated double bond may be used. The amount of the compound having a saturated double bond is preferably 0.5 to 10 mol% with respect to the total acid component or the total polyol component, more preferably 2 to 7 mol%, and further preferably 3 to 6 mol%. %. When the dicarboxylic acid having a polymerizable unsaturated double bond is 0.5 mol% or less, it is difficult to effectively graft the radically polymerizable monomer onto the polyurethane resin, and the dispersed particle diameter in the aqueous medium is It tends to increase, and the dispersion stability tends to decrease. 0.5 mol%
If less than the effective grafting of the acrylic monomer composition to the polyurethane resin is not performed, a homopolymer consisting only of the radically polymerizable monomer composition is mainly produced, it is not possible to obtain the target modified resin .

On the other hand, the glycol component comprises an aliphatic glycol having 2 to 10 carbon atoms and / or an alicyclic glycol having 6 to 12 carbon atoms and / or an ether bond-containing glycol, Examples of the aliphatic glycol having 2 to 10 carbon atoms include ethylene glycol and 1,2-propylene glycol.
1,3-propanediol, 1,4-butanedio-
1,5-pentanediol, neopentylglycol
1,6-hexanediol, 3-methyl-1,5-
Pentanediol, 1,9-nonanediol, 2-ethyl-2-butylpropanediol, hydroxypivalic acid neopentyl glycol ester, dimethylolheptane and the like can be mentioned, and alicyclic glycos having 6 to 12 carbon atoms. -, As 4-l, 1,4-cyclohexanedimethano-
And tricyclodecane dimethanol. The ether bond-containing glycols include diethylene glycol, triethylene glycol, dipropylene glycol, and two phenols of bisphenols.
Examples thereof include glycols obtained by adding one to a few moles of ethylene oxide or propylene oxide to the hydroxyl group, such as 2,2-bis (4-hydroxyethoxyphenyl) propane. Polyethylene glycol, polypropylene glycol and polytetramethylene glycol can also be used if necessary.

In the polyester resin used in the present invention, 0 to 5 mol% of a trifunctional or higher polycarboxylic acid and / or polyol can be copolymerized. (Anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, (anhydrous) benzophenone tetracarboxylic acid, trimesic acid, ethylene glycol bis (anhydrotrimellitate), glycerol tris (anhydrotrimellitate) and the like are used. On the other hand, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like are used as the trifunctional or higher functional polyol. Trifunctional or higher polycarboxylic acid and /
Alternatively, the polyol is copolymerized in an amount of 0 to 5 mol%, preferably 0 to 3 mol% with respect to the total acid component or the total glycol component, but if it exceeds 5 mol%, sufficient processability is obtained. It becomes difficult to give.

The polyester polyol used in the present invention needs to have a weight average molecular weight of 500 to 10,000, preferably 700 to 7,000, and more preferably 1,000 to 5,000. When the weight average molecular weight is 500 or less, various physical properties of the urethane resin obtained from the raw material are deteriorated, and the urethane resin using the polyester polyol having the weight average molecular weight of 10,000 or more has a high viscosity during the grafting reaction. , The uniform progress of the reaction is hindered.

(Polyurethane Resin) The polyurethane resin in the present invention comprises a polyester polyol (a), an organic diisocyanate compound (b), and optionally a chain extender (c) having an active hydrogen group, and a molecular weight of 500.
0-100000, urethane bond content is 500-40
00 equivalent / 10 ⁶ g, and the polymerizable double bond content is 1.5 to 30 on average per chain.

Polyester polyol used in the present invention
(a) is produced by using the compounds exemplified in the section of polyester polyol as the dicarboxylic acid component and the glycol component component, and both end groups are hydroxyl groups and the molecular weight is 500.
It is preferably in the range of 10,000 to 10,000. The polyester polyol used in the present invention must have a dicarboxylic acid component of at least 60 mol% or more, preferably 70 mol% or more, of an aromatic dicarboxylic acid. An aliphatic polyester polyol widely used for general polyurethane resins, for example, a polyurethane resin using an adipate of ethylene glycol or neopentyl glycol has extremely low water resistance.

As an example, the reduced viscosity retention rate after 20 days of hot water immersion at 70 ° C. is as low as 20 to 30%. On the other hand, a resin having the same glycol terephthalate or isophthalate as the polyester polyol retains the reduced viscosity under the same conditions. The rate is as high as 80 to 90%. Therefore, for high water resistance of the coating film, it is necessary to use a polyester polyol mainly containing an aromatic dicarboxylic acid.

Further, polyether polyol, polycarbonate polyol, polyolefin polyol and the like can be used together with these polyester polyols, if necessary. Examples of the organic diisocyanate compound (b) used in the present invention include hexamethylene diisocyanate, tetramethylene diisocyanate, 3,3′-dimethoxy-4,4′-biphenylene diisocyanate,
p-xylylene diisocyanate, m-xylylene diisocyanate, 1,3-diisocyanate methylcyclohexane, 4,4′-diisocyanate dicyclohexane, 4,4′-diisocyanate cyclohexylmethane, isophorone diisocyanate, 2,4-tolylene diisocyanate, 2 , 6-tolylene diisocyanate,
p-phenylene diisocyanate, diphenylmethane diisocyanate, m-phenylene diisocyanate,
2,4-naphthalene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 4,
4'-diisocyanate diphenyl ether, 1,5-
Examples thereof include naphthalene diisocyanate.

In the present invention, the chain extender (c) having an active hydrogen group which is optionally used is, for example, ethylene glycol, propylene glycol, neopentyl glycol, 2,2-diethyl-1,3-propane. Examples thereof include glycols such as diol, diethylene glycol, spiroglycol and polyethylene glycol, and amines such as hexamethylenediamine, propylenediamine and hexamethylenediamine.

The polyurethane resin used in the present invention includes polyester polyol (a), organic diisocyanate (b),
And a chain extender (c) having an active hydrogen group, if necessary, in a ratio of active hydrogen group / isocyanate group of (a) + (c)
It is necessary that the polyurethane resin is obtained by reacting at a compounding ratio of 0.8 to 1.3 (equivalent ratio).

When the ratio of active hydrogen groups / isocyanate groups of (a) + (c) is out of this range, the urethane resin cannot have a sufficiently high molecular weight and desired coating film physical properties can be obtained. Absent.

The polyurethane resin used in the present invention is produced by a known method in a solvent at a reaction temperature of 20 to 150 ° C. in the presence of a catalyst or without a catalyst. As the solvent used at this time, for example, ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, and esters such as ethyl acetate and butyl acetate can be used. As the catalyst for accelerating the reaction, amines, organic tin compounds and the like are used. The polyurethane resin used in the present invention has a polymerizable double bond in an average of 1.5 to 1.5 per urethane chain in order to enhance the efficiency of the grafting reaction with the radically polymerizable monomer.
It is necessary to contain 30, preferably 2 to 20, more preferably 3 to 10.

Regarding the introduction of the polymerizable double bond, there are the following three methods: 1) An unsaturated dicarboxylic acid such as fumaric acid, itaconic acid or norbornene dicarboxylic acid is contained in the polyester polyol. 2) An allyl ether group-containing glycol is contained in the polyester polyol. 3) An allyl ether group-containing glycol is used as a chain extender. These can be carried out alone or in combination.

(Radical Polymerizable Monomer) The radical polymerizable monomer that can be graft-polymerized to the polyurethane resin has a radical group having a hydrophilic group or a group that can be changed to a hydrophilic group later. Polymerizable monomers and other radically polymerizable monomers. As a hydrophilic group,
Examples thereof include a carboxyl group, a hydroxyl group, a sulfonic acid group, an amide group, and a quaternary ammonium salt. Examples of the group that can be converted into a hydrophilic group include an acid anhydride group, a glycidyl group, and a chloro group. be able to. Among these hydrophilic groups, a carboxyl group is preferred because it is easy to control the water dispersibility by changing the acid value, and a radical polymerizable monomer having a carboxyl group or a group capable of generating a carboxyl group is preferred.

As the carboxyl group-containing radically polymerizable monomer which can be graft-polymerized on the polyurethane resin to change the acid value, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, etc. Examples thereof include maleic anhydride, itaconic anhydride, and methacrylic anhydride, which easily generate a carboxylic acid in contact with water / amine. One or more of these may be selected and used. . The most desirable carboxyl group-containing radically polymerizable monomers are acrylic acid, methacrylic acid and maleic anhydride. In the present invention, in addition to these carboxyl group-containing radical polymerizable monomers, it is usual to use together radical polymerizable monomers that do not contain carboxyl groups. A wide range of radically polymerizable monomers can be mentioned as the radically polymerizable monomer containing no carboxyl group. That is, as acrylic acid and methacrylic acid esters, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, -2 hydroxyethyl acrylate, hydroxypropyl acrylate, methyl methacrylate , Ethyl methacrylate, isopropyl methacrylate, methacrylic acid n-
Butyl, isobutyl methacrylate, n-hexyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, hydroxylpropyl methacrylate and the like, and further well known monomers include acrylonitrile, methacrylonitrile, acrylamide, N-. Methylol acrylamide, diacetone acrylamide, vinyl acetate, vinyl ethers, N-vinylpyrrolidone, styrene, α-methylstyrene, t-butylstyrene, vinyltoluene, etc. can be exemplified, and one or more of them can be used. Can be selected and used.

Further, the number of components of the radical-polymerizable monomer mixture is preferably 2 or more. The number of components is 1
In the case of only the carboxyl group-containing monomer, the grafting on the polyester chain does not occur smoothly, and it is difficult to obtain a good water dispersion. The second component, acrylic acid,
Grafting with high efficiency can be performed only by copolymerization with methacrylic acid esters.

Application of the radical copolymerization theory provides a powerful guide for the selection of the above-mentioned monomers. For example, diethyl fumarate (monomer 1), Q, e value of each monomer (monomer 2) (for example, Polymer Handbook, 3rd. Ed.
John Wiley and Sons, 1989) and using the formula r ₂ = Q ₂ / Q ₁ exp [-e ₂ (e ₂ -e ₁ )], the copolymerization reactivity ratio of each monomer to diethyl fumarate (hereinafter r ₂ value) Can be asked).

The inventors of the present invention have prepared a copolyester in which any one of fumaric acid, maleic acid, and 2,5-norbornenedicarboxylic acid is copolymerized depending on the copolymerizable reactivity ratio of diethyl fumarate and various monomers. It was found that the reactivity of the radically polymerizable monomer, specifically the grafting efficiency, and the gelation tendency of the crosslinking reaction can be predicted. That is, among the monomers listed above, acrylic acid, methacrylic acid and their esters, nitriles, amides, etc. r ₂
When a monomer mixture consisting of monomers having a value of 1 to 12 is subjected to grafting by the dropwise addition method, gelation can be avoided, while the above-mentioned monomer mixture has an r ₂ value of 10 ^-1. ~ 10 ^-4
When a monomer having an r ₂ value of 1 or less, such as styrene, vinyl acetate, vinyl ether, or N-vinylpyrrolidone, which is an order value, is used in combination, crosslinking between polyester molecules during the grafting reaction is very likely to occur. I found a lot.

The inventors of the present invention further investigated various methods of utilizing a monomer having an r ₂ value of 1 or less, and made the following new discoveries. That is, maleic anhydride, fumaric acid diester, maleic acid diester and the like have a low homopolymerizable monomer having a high electron accepting property together with a polymerizable double bond-containing polyurethane resin, and have a high electron donating property. It has been found that if styrenes, vinyl esters, vinyl ethers, etc. are subjected to the reaction, the grafting reaction is carried out very smoothly and the subsequent amine / water gives a good aqueous dispersion without gelation. in this case,
The graft chain is an alternating copolymer chain of an electron-accepting monomer and an electron-donating monomer, and has an r ₂ value of 1 to 1 as described above.
This contrasts with the graft chain composed of monomers in the range of 2 being a random copolymer chain. There is no description of such a graft polymer in the prior art already mentioned.

The weight ratio of the monomer containing a carboxyl group and the monomer not containing a carboxyl group is 95/5 to 5 /
It is in the range of 95, and more preferably 90/10 to 10/90, but it is necessary to determine it in consideration of the acid value imparted to the graft reaction product. The total acid value of before being neutralized polyurethane graft polymerization reaction product in the present invention is desirably 600~4000eq. / 10 ⁶ g, more preferably is 700~3000eq. / 10 ⁶ g, Most preferably, it is 800-2500 eq./10 ⁶ g. When the acid value is 600 eq./10 ⁶ g or less, it is difficult to obtain a dispersion having a small particle size when dispersed in water, and the dispersion stability tends to decrease. Acid value is 40
When it is 00 eq./10 ⁶ g or more, the water resistance of the coating film formed from the aqueous dispersion tends to be low.

(Grafting Reaction) The polyurethane-based graft polymer can be efficiently obtained by graft-polymerizing a radically polymerizable monomer onto the polymerizable unsaturated double bond in the polyurethane resin. In the present invention, generally, in a state in which a polyurethane resin is dissolved in an organic solvent,
It is carried out by reacting a radical initiator and a radically polymerizable monomer mixture. The reaction product after the completion of the grafting reaction includes a desired graft polymer between the polyurethane resin-radical polymerizable monomer mixture, a polyurethane resin not grafted and a radical polymer not grafted with the polyurethane resin. Although it is considered that the content of the graft polymer in the reaction product is low and the ratio of the non-grafted polyurethane resin and the non-grafted radical polymer is high in the reaction product, an aqueous dispersion having good stability may be obtained. Can not.

(Mode of Grafting Reaction) When carrying out the grafting reaction of the radically polymerizable monomer on the polyurethane resin, the radically polymerizable monomer mixture is added to the polyurethane resin dissolved in a solvent while heating. The radical initiator may be added at one time, or the reaction may be separately added dropwise over a certain period of time, and then the reaction may be continued by continuing heating with stirring for a certain period of time. In addition, after adding a part of the monomer at a time, the remaining monomer and the initiator are separately added dropwise over a certain period of time, and then the reaction is continued by further heating for a certain period of time with stirring. It is also made to proceed if necessary.

Prior to the reaction, a polyurethane resin and a solvent are charged into a reactor and the temperature is raised with stirring to dissolve the resin. The weight ratio of the polyurethane resin to the solvent is preferably 70/30 to 30/70. In this case, the weight ratio is adjusted to a weight ratio that allows a uniform reaction during the polymerization process, taking into consideration the reactivity between the polyurethane resin and the radical-polymerizable monomer, which will be described later, and the solvent solubility.

The grafting reaction temperature is 50 ° C to 120 ° C.
It is desirable to carry out in the range of ° C. A desirable weight ratio of the polyurethane resin and the radical-polymerizable monomer suitable for the purpose of the present invention is in the range of 40/60 to 95/5, more preferably 55/45 in terms of polyurethane / radical-polymerizable monomer. ~ 93/7, most preferably 60/4
It is in the range of 0 to 90/10.

40% by weight of polyurethane resin
When it is the following, excellent performance of the base polyurethane resin already described, namely elasticity, high processability, excellent water resistance, it is not possible to sufficiently exhibit excellent adhesion to various substrates,
Conversely, the undesired performance of acrylic resin, that is, low processability,
It will add gloss and water resistance. When the weight ratio of the polyurethane resin is 95% by weight or more, the amount of carboxyl groups in the radical-polymerizable monomer-grafted branch chain responsible for hydrophilization becomes insufficient, and a good water dispersion cannot be obtained.

(Radical Initiator etc.) Well-known organic peroxides and organic azo compounds can be used as the radical polymerization initiator used in the present invention. That is, benzoylperoxide, t-butylperoxypivalate as an organic peroxide and 2,2'- as an organic azo compound.
Examples thereof include azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile).

Regarding the selection of the radical initiator compound,
It is necessary to consider the radical generation rate of the compound at the reaction execution temperature, that is, the half-life. Generally, it is desirable to select a radical initiator having a half-life value at that temperature in the range of 1 minute to 2 hours.

The amount of the radical initiator used for carrying out the grafting reaction should be at least 0.2% by weight based on the radical-polymerizable monomer, preferably 0.5.
It is necessary to use more than weight%.

Addition of a chain transfer agent such as octyl mercaptan or mercaptoethanol is also used as necessary for controlling the graft chain length. In that case, it is desirable to add the radically polymerizable monomer in an amount of 0 to 5% by weight.

(Reaction Solvent) The grafting reaction solvent for carrying out the present invention is preferably composed of an aqueous organic solvent having a boiling point of 50 to 250 ° C. Here, the aqueous organic solvent has a solubility in water at 20 ° C. of at least 10 g /
L or more, preferably 20 g / L or more.
Those having a boiling point of higher than 250 ° C. are not suitable because the evaporation rate is too slow and they cannot be removed sufficiently by high temperature baking of the coating film. When the boiling point is 50 ° C or lower,
When carrying out the grafting reaction using it as a solvent, 50
Since an initiator that cleaves into radicals at a temperature of ℃ or less must be used, the handling risk increases, which is not preferable.

As a first group of aqueous organic solvents which dissolves urethane resin containing copolymerized polyester polyol well and dissolves a polymerizable monomer mixture containing a carboxyl group-containing polymerizable monomer and its polymer relatively well Are esters such as ethyl acetate, ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclic ethers such as tetrahydrofuran, dioxane,
1,3-dioxolane, glycol ethers such as ethylene glycol dimethyl ether, propylene glycol methyl ether, propylene glycol propyl ether, ethylene glycol ethyl ether, ethylene glycol butyl ether, carbitols such as methyl carbitol , Ethyl carbitol, butyl carbitol
Lower esters of glycols, glycols or glycol ethers such as ethylene glycol diacetate, ethylene glycol ethyl ether acetate, ketone alcohols such as diacetone alcohol, and N-substituted amides such as dimethylformamide and dimethyl. Acetamide, N-methylpyrrolidone, etc. can be illustrated.

On the other hand, water is used as the second group of aqueous organic solvents which dissolves the polyurethane resin in a relatively small amount but relatively dissolves the polymerizable monomer mixture containing the carboxyl group-containing polymerizable monomer and the polymer. , Lower alcohols, lower carboxylic acids, lower amines, etc., but particularly preferred for the practice of the present invention are alcohols and glycols having 1 to 4 carbon atoms.

When the grafting reaction is carried out in a single solvent, only one kind can be selected from the first group of aqueous organic solvents. When the mixed solvent is used, there may be a case where a plurality of types are selected only from the first group of aqueous organic solvents, or at least one type is selected from the first group of aqueous organic solvents and at least one type is added to the second group of aqueous organic solvents.

Whether the graft polymerization reaction solvent is a single solvent from the first group of aqueous organic solvents or a mixed solvent consisting of one of the first group and second group of aqueous organic solvents is used. A graft polymerization reaction can be performed. However, there are differences in the progress behavior of the grafting reaction, the appearance and properties of the grafting reaction product and the water dispersion derived therefrom, and the mixed solvent consisting of one kind of the first and second groups of aqueous organic solvents Is preferred.

That is, tetrahydrofuran, which belongs to the first group of aqueous organic solvents and which has the strongest dissolving power for a polyester resin, a monomer mixture containing a carboxyl group-containing polymerizable monomer and a polymer derived therefrom, is used as a simple solvent. When one solvent is used, the grafting reaction always proceeds with a transparent appearance. In some cases, the viscosity of the system gradually increases, and in the latter stage of the grafting reaction, the viscosity increases remarkably and the reaction cannot be continued. In such a case, the reaction product is transparent and rubber-like with the solvent taken up, indicating the formation of a gel that does not dissolve in a strong solvent. To avoid this, it is necessary to drastically reduce the resin concentration, which is not a rational method in manufacturing. On the other hand, a mixed solvent system obtained by selecting methyl ethyl ketone from the first group of aqueous organic solvents, selecting isopropyl alcohol from the second group of aqueous organic solvents, and mixing both at a weight ratio of 75/25. When the solubility of the copolyester used is adjusted, the same polyester resin, the same radical polymerizable monomer composition ratio, the same polyester / radical polymerizable monomer ratio, and the same as those of tetrahydrofuran are used. Even when the reaction is carried out with the resin solid content, neither thickening nor gelation of the system is observed with the progress of the grafting reaction. Further, the subsequent aqueous system gives a good aqueous dispersion. From this, it can be understood that the use of the mixed solvent system is a rational process which can increase the resin solid content concentration during production and can reduce the amount of organic solvent used during production.

In the solvent of the first group, the polyurethane molecular chain is in a state where the chain having a large spread is extended, while in the mixed solvent of the first group / the second group, it is in a state of being entangled in a thread form having a small spread. Was confirmed by measuring the viscosity of the polyurethane resin in these solutions. It is effective to prevent gelation by controlling the dissolved state of the polyurethane resin to prevent intermolecular crosslinking. The compatibility of highly efficient grafting and suppression of gelation is achieved in the latter mixed solvent system. The weight ratio of the mixed solvent of the first group / second group is more preferably 95 /
5 to 10/90, more preferably 90/10 to 20/8
0, most preferably 85/15 to 30/70. The optimum mixing ratio is determined according to the solubility of the polyurethane resin used and the like.

(Water Dispersion) The grafting reaction product according to the present invention is preferably neutralized with a basic compound,
By neutralizing, it is possible to easily disperse in water into fine particles having an average particle size of 500 nm or less. As the basic compound, a compound that volatilizes during coating film formation or bake-curing with a curing agent is preferable, and ammonia, organic amines and the like are preferable. Examples of desirable compounds include triethylamine, N, N-diethylethanolamine, N, N-dimethylethanolamine, aminoethanolamine, N-methyl-N, N-diethanolamine, isopropylamine,
Iminobispropylamine, ethylamine, diethylamine, 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, dimethylaminopropylamine, methyliminobispropylamine, 3-methoxypropylamine, Mention may be made of monoethanolamine, diethanolamine, triethanolamine and the like. The basic compound is at least partially neutralized depending on the carboxyl group content contained in the grafting reaction product,
Alternatively, the pH value of the aqueous dispersion is 5.0 by complete neutralization.
It is desirable to use it so that it is in the range of to 9.0.

In carrying out the dispersion in water, the solvent contained in the grafting reaction product is previously removed by an extruder under reduced pressure to form a grafting reaction in a melt form or a solid form (pellets, powders, etc.). It is also possible to prepare an aqueous dispersion by throwing the product into water containing a basic compound and stirring under heating, but most preferably, the water containing the basic compound is immediately added at the time when the grafting reaction is completed. A method (one-pot method) of charging the mixture and continuing heating and stirring to obtain an aqueous dispersion is preferable. Furthermore, the boiling point of the solvent
When the temperature is 100 ° C. or lower, a part or all of the solvent used for the grafting reaction can be easily removed by distillation.

The solid content concentration of the aqueous dispersion produced according to the present invention is 20 to 60% by weight, and water can be used by diluting it by adding water if necessary.

(Characteristics of Aqueous Dispersion) The aqueous dispersion produced according to the present invention has a weight average molecular weight of 5000 to 50 as a raw material.
It is preferable to use a polyurethane resin of 000.
When the weight average molecular weight is 5,000 or less, the physical properties of the resin such as the post-processability of the dry coating film tend to deteriorate. When the weight average molecular weight is further lower, the polyurethane resin itself tends to be water-soluble and does not form a core-shell structure described later. Further, a polyurethane resin having a weight average molecular weight of 50,000 or more tends to be difficult to disperse in water.

In the aqueous dispersion produced according to the present invention,
The weight average molecular weight of the polymer of the radically polymerizable monomer is 500.
It is preferably ˜50,000. It is generally difficult to control the weight-average molecular weight of the polymer of the radical-polymerizable monomer to 500 or less, the grafting efficiency decreases, and there is a tendency that the hydrophilic group is not sufficiently imparted to the copolyester. is there. Further, the graft polymerization product of the radical-polymerizable monomer forms a hydrated layer of dispersed particles, but in order to obtain a stable dispersion by providing a hydrated layer of a sufficient thickness, the radical-polymerizable monomer of The weight average molecular weight of the graft polymer is 500
The above is desirable. The upper limit of the weight average molecular weight of the graft-polymerized product of the radical-polymerizable monomer is preferably 50,000 from the viewpoint of polymerizability in solution polymerization. The control of the molecular weight within this range is the amount of the initiator, the monomer dropping time,
Polymerization time, reaction solvent, monomer composition or, if necessary, a chain transfer agent and a polymerization inhibitor may be appropriately combined to carry out.

The aqueous dispersion according to the present invention has a mean particle size of 500 nm or less as measured by a laser light scattering method and has a semitransparent or milky white appearance. The water-based dispersion obtained in the present invention can have various particle diameters by adjusting the polymerization method, and the particle diameter is preferably 10 nm to 500 nm. If it exceeds 500 nm, the surface gloss may decrease during film formation.

When the ¹³ C-NMR of the aqueous dispersion of the present invention was measured, the full width at half maximum of the signal of the carbonyl group of the ester portion of the polyester polyol was as large as 300 Hz or more, and the carboxyl group neutralized by the basic compound was contained. The full width at half maximum of the signal of the carboxyl group of the polymer of the radical-polymerizable monomer containing the radical-polymerizable monomer is observed to be as small as 150 Hz or less. Generally, in NMR, the full width at half maximum of the signal observed from the resin dissolved in the measurement solvent is small,
The full width at half maximum of the signal observed from the resin that is insoluble in the measurement solvent is large.

From the above, in the water-based dispersion of the present invention, the polyurethane resin, which is originally not dispersed or dissolved in water, exists as the core portion in the agglomerated state, and the periphery thereof contains the carboxyl group neutralized by the basic compound soluble in water. It has a structure in which a polymer of a radical-polymerizable monomer containing a radical-polymerizable monomer is wrapped as a shell part, and a core-shell structure is expressed in a fine particle state. The core-shell structure refers to a two-layer particle structure in which a core portion made of a resin insoluble in the dispersion medium and in an aggregated state is wrapped with a shell portion made of a resin in the dispersion medium soluble in a dissolved state. This structure is a structure in which resins having different solubilities in the dispersion medium are chemically bonded to each other but characteristically appears in the dispersion, and cannot be expressed simply by mixing resins having different solubilities in the dispersion medium. It is a structure. Further, a mixture of resins having different solubility in a dispersion medium cannot exist as an aqueous dispersion having a particle size of 500 nm or less.

In the present invention, various characteristics of the water dispersion can be recognized by giving the dispersion particles such a structure. One is the stability of the aqueous dispersion, which gives a stable aqueous dispersion when an aqueous dispersion of a polymer polyurethane resin is used without using an emulsifier or an organic cosolvent which is often used for other aqueous dispersions. This is because the resin in the shell portion forms a sufficient hydration layer and protects the dispersed particles. In addition, this aqueous dispersion has excellent redispersibility because it has a sufficiently thick shell portion. Here, the redispersibility means that the film formed from the aqueous dispersion loses water and the organic solvent at room temperature,
It means the property of being able to be dispersed again in water or an undiluted solution of an aqueous dispersion, and is a property that is very important for aqueous resins used in the fields of paints and inks. If the water dispersion is used for ink, paint, coating material, etc.
Since the dried portion which is partially formed during the coating operation is not dispersed again in the coating liquid, it may cause a defect in the coating film or cause clogging of the roller or the spray gun. When the aqueous dispersion of the present invention is applied to a substrate and dried by heating, the dispersion particles lose the above structure to form a uniform coating film, which has excellent processability with the polyurethane resin in the core portion,
Develops adhesion and water resistance.

(Use of Aqueous Dispersion) The aqueous dispersion according to the present invention is used as a vehicle for paints, inks, coating materials, adhesives, etc. or as a processing agent for fibers, films and paper products. The aqueous dispersion of the present invention can be used as it is, but by incorporating a crosslinking agent (curing resin) and performing bake curing, a high degree of water resistance can be exhibited. Examples of the cross-linking agent include phenol formaldehyde resin, amino resin, polyfunctional epoxy compound, polyfunctional isocyanate compound and various blocked isocyanate compounds thereof, and polyfunctional aziridine compound.

Examples of the phenol resin include formaldehyde condensation products of alkylated phenols and cresols. Specifically, alkylated (methyl, ethyl, propyl, isopropyl, butyl) phenol, p-tert-amylphenol, 4,4'-sec-butylidenephenol, p-tert-butylphenol, o-, m-, p -Formaldehyde condensation of cresol, p-cyclohexylphenol, 4,4'-isopropylidenephenol, p-nonylphenol, p-octylphenol, 3-pentadecylphenol, phenol, phenyl o-cresol, p-phenylphenol, xylenol, etc. Things can be mentioned.

Examples of amino resins include formaldehyde adducts such as urea, melamine and benzoguanamine,
Further, an alkyl ether compound containing an alcohol having 1 to 6 carbon atoms can be mentioned. Specifically, methoxylated methylol urea, methoxylated methylol
N, N-ethylene urea, methoxylated methylol dicyandiamide, methoxylated methylol melamine, methoxylated methylol benzoguanamine, butoxylated methylol melamine, butoxylated methylol benzoguanamine, but preferably methoxylated methylol melamine, butoxylated methylol melamine, and methylol Benzoguanamine, which can be used alone or in combination.

Bisphenol A as an epoxy compound
Diglycidyl ether and its oligomer, hydrogenated bisphenol A diglycidyl ether and its oligomer, orthophthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, p-oxybenzoic acid diglycidyl ester, tetrahydrophthalic acid Acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, succinic acid diglycidyl ester, adipic acid diglycidyl ester, sebacic acid diglycidyl ester, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol di Glycidyl ether, 1,6-hexanediol diglycidyl ether and polyalkylene glycol diglycidyl ethers, trimellitic acid trig Lycidyl ester, triglycidyl isocyanurate, 1,4-diglycidyloxybenzene, diglycidyl propylene urea, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol triglycidyl ether, triglycidyl ether of glycerol alkylene oxide adduct And so on.

Further, as the isocyanate compound, there are aromatic and aliphatic diisocyanates and polyisocyanates having a valence of 3 or more, and either low molecular weight compounds or high molecular weight compounds may be used. For example, tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate or trimer of these isocyanate compounds, and excess of these isocyanate compounds. The amount of the low molecular weight active hydrogen compound such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine or various polyester polyols, polyether polyols, polyamides Conflicts with high molecular weight active hydrogen compounds It includes terminal isocyanate group-containing compounds obtained by.

The isocyanate compound may be a blocked isocyanate. Examples of the isocyanate blocking agent include phenol, thiophenol,
Methylthiophenol, cresol, xylenol, resorcinol, nitrophenol, chlorophenol and other phenols, acetoxime, methyl ethyl ketoxime, cyclohexanone oxime and other oximes, methanol, ethanol, propanol, butanol and other alcohols, ethylene chlorohydrin, 1, Halogen-substituted alcohols such as 3-dichloro-2-propanol,
Tertiary alcohols such as t-butanol and t-pentanol, lactams such as ε-caprolactam, δ-valerolactam, γ-butyrolactam and β-propyllactam, and other aromatic amines and imides. , Active methylene compounds such as acetylacetone, acetoacetic acid ester, malonic acid ethyl ester, mercaptans,
Examples include imines, ureas, diaryl compounds, sodium bisulfite, and the like. The blocked isocyanate is obtained by subjecting the above isocyanate compound, an isocyanate compound and an isocyanate blocking agent to an addition reaction by a conventionally known appropriate method.

The method of blending the cross-linking agent is as follows: (1) When the cross-linking agent is aqueous, it is directly dissolved or dispersed in an aqueous dispersion, and (2) When the cross-linking agent is oily, it is dispersed in water after completion of the grafting reaction. A method is used in which a crosslinking agent is added to the core portion before or after the addition of the polyurethane resin to coexist with the polyurethane resin,
It can be arbitrarily selected depending on the type and properties of the crosslinking agent. A curing agent or an accelerator may be used in combination with these crosslinking agents.

The curing reaction generally depends on the aqueous dispersion 1 of the present invention.
It is carried out by mixing 5 to 40 parts (solid content) of the curing resin with 00 parts (solid content) and heating at a temperature range of 60 to 250 ° C. for about 1 to 60 minutes depending on the type of the curing agent. If necessary, a reaction catalyst and a promoter are also used in combination. The aqueous dispersion of the present invention may be blended with pigments, dyes, various additives and the like. The aqueous dispersion of the present invention can be used in combination with other aqueous resins and aqueous dispersions, and the processability thereof can be improved.

Furthermore, since the paints, inks, coating agents, adhesives, and various processing agents based on the aqueous dispersion according to the present invention are excellent in redispersibility, dip coating method, brush coating method, and roll method. It has applicability to all coating methods, spraying methods, and various printing methods. Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

[0064]

EXAMPLES The present invention will be described below with reference to examples. In the examples, "parts" means "parts by weight" and "%" means "% by weight". Each measurement item followed the following method. (1) Weight average molecular weight Dissolve 0.03 g of resin in 10 cc of tetrahydrofuran,
PC-LALLS device Low angle light scattering photometer LS-8000 (manufactured by Tosoh Corporation, tetrahydrofuran solvent, reference: polystyrene) was used for measurement.

(2) Polyurethane grafting efficiency The product obtained by graft polymerization was analyzed by 220 MHz ¹ H-NMR.
And 55 MHz ¹³ C-NMR (Varian, measurement solvent CDCl
₃ / DMSO-d6), and the grafting efficiency was measured based on the intensity change of the signal derived from the double bond of the double bond-containing component copolymerized with polyurethane. Polyurethane grafting efficiency = (1- (relative intensity of signal derived from double bond of double bond-containing component of graft polymerization product / relative intensity of signal derived from double bond of double bond-containing component of raw material polyester)) × 100 (%) The relative intensity was calculated by comparison with the signal intensity of the internal signal as a reference signal.

(3) Weight average molecular weight measurement of graft side chain The product obtained by graft polymerization was subjected to hydrolysis of the copolyester polyurethane under reflux in a KOH / water-methanol solution. Decomposition products under acidic conditions in THF
Was used for extraction, and the acrylic polymer was purified by reprecipitation with hexane. This polymer was measured with a GPC apparatus (manufactured by Shimadzu Corporation, tetrahydrofuran solvent, converted to polystyrene), and the weight average molecular weight of the graft side chain was calculated.

(4) Aqueous dispersion particle size The aqueous dispersion was adjusted to a solid content concentration of 0.1 wt% with ion-exchanged water, and a laser light scattering particle size distribution analyzer Coulter model N4 was used.
(Manufactured by Coulter) at 20 ° C. (5) Aqueous dispersion B type viscosity The viscosity of the aqueous dispersion is measured by a rotational viscometer (EM, manufactured by Tokyo Keiki Co., Ltd.).
Type) and was measured at 25 ° C.

(6) Redispersibility of aqueous dispersion An aqueous dispersion was coated on a glass plate so that the film thickness after drying was 15 μm, and dried at room temperature for 1 hour. The coated plate obtained was dipped in distilled water to compare it with that before dipping.
The comparison was made by the following five-stage evaluation. Rank 1: No change in appearance of coating film before and after soaking 2: Whitening of coating film surface 3: Peeling of coating film, but not redispersion in distilled water 4: Peeling of coating film, slight peeling in distilled water Re-dispersed with insoluble matter 5: The coating film peels off and is completely re-dispersed in distilled water

(7) Measurement of ¹³ C-NMR FWHM The aqueous dispersion was diluted with heavy water to a solution concentration of 20% by weight and DSS was added to prepare a sample. After setting the measurement conditions so that the full width at half maximum of the DSS signal is 5 Hz or less, the carbonyl of the copolyester polyol in the urethane resin when 125 MHz ¹³ C pulse Fourier transform NMR (manufactured by Varian) was measured at 25 ° C. The full width at half maximum of the carbonyl group carbon in the polymer portion of the radical-polymerizable monomer graft-polymerized with the group carbon was measured. (8) Hardened coating film hardness (pencil hardness) The coated surface of the steel plate is a high-grade pencil specified in JIS S-6006,
It was measured according to JIS K-5400. (9) Cured coating gloss With a gloss meter (VG107 manufactured by Nippon Denshoku Kagaku Co., Ltd.)
The 60 degree reflectance was measured.

(10) Flexibility of cured coating film The coated steel sheet was bent 180 degrees, and cracks generated in the bent portion were observed and judged with a magnifying glass of 10 times. 4T refers to the case where cracks do not occur in the bent part even when four bent parts with the same plate thickness are sandwiched. (11) Adhesion of cured coating film According to ASTM D-3359.

(12) Solvent resistance of cured coating film The film was rubbed with a gauze impregnated with xylene, and the number of times until the undercoat appeared was recorded.

(13) Water resistance of the cured coating film 25 solid parts of melamine (Sumimar M30W, manufactured by Sumitomo Chemical Co., Ltd.) and 0.25 solid of paratoluenesulfonic acid (catalyst) per 100 solid parts of the aqueous dispersion. Parts, 100 parts of titanium oxide, and 250 parts of glass beads were mixed and shaken and dispersed for 5 hours with a paint shaker. Then,
It was applied on a zinc iron plate so that the film thickness after drying would be 15 μm, and baked at 230 ° C. for 1 minute. The coated plate thus obtained was boiled in boiling water for 2 hours and evaluated by gloss retention (%).
The gloss retention rate was calculated by the following formula. Gloss retention rate (%) = (Gloss after treatment / Initial gloss) x 1
00

(14) Smoothness: visually determined. (15) A sample with an acid value of 1 g (solid content) is added to 30 cc of chloroform or DMF.
It was then dissolved in and was titrated with KOH using phenolphthalein as an indicator to determine the equivalent of carboxyl groups per 10 ⁶ g of the sample.

Production Example of Polyester Polyol In a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser, 466 parts of dimethyl terephthalate, 466 parts of dimethyl isophthalate, 401 parts of neopentyl glycol, 443 parts of ethylene glycol, and Charge 0.52 parts of tetra-n-butyl titanate,
The transesterification reaction was carried out from 160 ° C to 220 ° C for 4 hours. Next, add 23 parts of fumaric acid to 200 ℃ to 220 ℃
The temperature was raised to 1 hour, and the esterification reaction was carried out.
Then raise the temperature to 255 ° C and gradually reduce the pressure in the reaction system.
The reaction was carried out for 30 minutes under a reduced pressure of 0.5 mmHg to obtain a polyester polyol (A-1). Obtained polyester polyol
(A-1) was light yellow and transparent and had a reduced viscosity of 0.3. The composition measured by NMR and the like was as follows.

Dicarboxylic acid component 48 mol% terephthalic acid 48 mol% isophthalic acid 4 mol% Fumaric acid 4 mol% Diol component Neopentyl glycol 50 mol% Ethylene glycol 50 mol% Various polyester polyols (A- 2-7) were produced. Table 1 shows the reduced viscosity of each polyester and the composition analysis results measured by NMR and the like.
In the table, each component indicates the number of moles.

[Table 1]

Production Example 1 of Polyurethane Resin The reduced viscosity obtained in the production example of polyester polyol was 0.1.
100 parts of polyester polyol (A-1) of 3 are thermometer,
In a reactor equipped with a stirrer and a reflux condenser, 120 parts of methyl ethyl ketone was charged and dissolved, and then 3 parts of neopentyl glycol, 15 parts of isophorone diisocyanate and 0.02 part of dibutyltin laurate were charged, and the temperature was 60 to 70 ° C.
And reacted for 6 hours. Then, the reaction system was cooled to 70 ° C. to stop the reaction. Obtained polyurethane resin (B-1)
Had a reduced viscosity of 0.55. Polyurethane was produced by the same method. Reduced viscosity and N of each polyurethane
Table 2 shows the composition analysis results measured by MR and the like. In the table, each component indicates the number of moles.

[0077]

[Table 2]

Production Example 2 of Polyurethane Resin Polyester polyol (A-1), diphenylmethane diisocyanate and propylene glycol were each added to 100 parts.
From the storage tank stored at ℃, 50 ℃, 25 ℃, using a gear pump, transfer the solution at the following volume, and put it into a twin-screw extractor (L / D = 40) with a screw diameter of 30 mm at the final resin temperature. Polyurethane was continuously melt-polymerized while kneading at a temperature of 230 ° C. Polyester polyol: 108.7 parts / min Propylene glycol: 5.8 parts / min Diphenylmethane diisocyanate: 36.0 parts / min Molten polyurethane resin is discharged in stride form from the die part of a twin-screw extractor and water-cooled in a cooling bath. Then, after pelletizing with a strand cutter, it was dried and cured for 30 hours at 60 ° C. in a nitrogen gas stream to obtain a pelletized polyurethane resin. Obtained polyurethane resin (B-
The reduced viscosity of 9) was 1.06.

Example 1 150 parts of a methyl ethyl ketone solution of polyurethane resin (B-1) (solid content 50%) and 15 parts of isopropyl alcohol were placed in a reactor equipped with a stirrer, a thermometer, a reflux device and a metering dropping device. After heating to 65 ° C, 0.2 parts of a mixture of 17.5 parts of methacrylic acid and 7.5 parts of ethyl acrylate and 1.2 parts of azobisdimethylvaleronitrile dissolved in a mixed solution of 25 parts of methyl ethyl ketone and 5 parts of isopropyl alcohol are added.
It was dripped into the polyester solution at ml / min, and stirring was continued for another 2 hours. Sampling for analysis from reaction solution (5
g), 300 parts of water and 25 parts of triethylamine were added to the reaction solution, and the mixture was stirred for 1 hour. Then, the temperature of the dispersion was raised to 100 ° C., and methyl ethyl ketone, isopropyl alcohol, and excess triethylamine were distilled off by distillation. The resulting aqueous dispersion (C-1) was white and had an average particle size of 300.
The B type viscosity at nm, 25 ° C. was 50 cps.

To 5 g of this aqueous dispersion, 1.25 g of heavy water was added to adjust the solid concentration to 20% by weight, DSS was added, and 125 MHz ¹³ C-NMR was applied.
Was measured. The FWHM of the carbon signal of the carbonyl group of the raw material polyester polyol (165 to 175 ppm) is ∞ (no signal is detected), and the FWHM of the carbon signal of the carbonyl group of methacrylic acid (181 to 186 ppm) is 240 Hz.
Met. When this aqueous dispersion was allowed to stand at 40 ° C for 60 days, no change in appearance was observed, and there was no change in viscosity, indicating excellent storage stability. The obtained water dispersion was applied onto a glass plate so that the solid film thickness was 15 μm. When this coating film was air-dried at room temperature for 1 hour and then immersed in distilled water, the coating film immediately dispersed in water and showed excellent redispersibility of ranks 4 to 5.

At the end of the grafting reaction, the sampled solution was dried under vacuum at 100 ° C. for 8 hours, and the solid content was measured for acid value, polyurethane grafting efficiency (measurement by NMR), and grafting by hydrolysis. The molecular weight of the side chain was measured. Acid value of solid content is 2300 eq./10 ⁶ g
Met. ^{In the 1} H-NMR measurement, a signal derived from fumaric acid (δ = 6.8 to 6.9 ppm, doublet) was not detected at all, and thus the polyurethane grafting efficiency was 100%. When the solid content polyurethane was hydrolyzed and the molecular weight of the acrylic polymer was measured by GPC, the weight average molecular weight was 5,000.

Examples 2 to 7 Various aqueous dispersions (C-2 to 7) were produced in the same manner as in Example 1. The performance of each of the obtained aqueous dispersions is shown in Table 3.

Comparative Example 1 Polyester polyol (A-7) was used to prepare polyurethane (B
-8) was synthesized with the composition shown in Table 2, and an aqueous dispersion (C-8) was produced in the same manner as in Example 1. The performance of the obtained aqueous dispersion is shown in Table 3.
It was shown to.

Examples 8 to 11 Aqueous dispersions (C
-9-12) was produced. The performance of each of the obtained water dispersions is shown in Table 4.
It was shown to.

Comparative Examples 2 to 5 Various water dispersions (C-13 to 16) were produced in the same manner as in Example 1 with the compounding ratios shown in Table 4. The performance of each of the obtained aqueous dispersions is shown in Table 4.

Comparative Example 6 (DMPA type) 100 parts of polyester polyol was charged and dissolved together with 100 parts of toluene in a reactor equipped with a thermometer, a stirrer and a reflux condenser, and then dissolved, then 3 parts of dimethylolpropionic acid, and 15 parts of isophorone diisocyanate. And 0.02 part of dibutyltin laurate were charged and reacted at 60 to 70 ° C. for 6 hours. Then, the reaction system was cooled to 70 ° C. to stop the reaction. The reduced viscosity of the obtained polyurethane resin was 0.55. The resulting polyurethane was dried under reduced pressure, and then 34 parts of polyurethane and ethylene glycol-n-butyl ether 1
0.8 part was charged in a container and stirred at 150 to 170 ° C. for 2 hours to obtain a uniform and viscous solution.
Neutralize with 5 parts, add 55.2 parts of water with vigorous stirring,
After 1 hour, a uniform pale blue-white aqueous dispersion (C-15) was obtained.
The obtained water dispersion was applied onto a glass plate so that the solid film thickness was 15 μm, and the redispersibility was evaluated in the same manner as in Example. The redispersibility rank was 1.

Comparative Example 7 (GCM Polyurethane) In a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser, 475 parts of dimethyl terephthalate, 465 parts of dimethyl isophthalate, 401 parts of neopentyl glycol, 443 parts of ethylene glycol 443. And 0.52 parts of tetra-n-butyl titanate,
The transesterification reaction was carried out from 160 ° C to 220 ° C for 4 hours. Then 5-sodium sulfoisophthalic acid 45
Parts were added and the temperature was raised from 200 ° C. to 220 ° C. over 1 hour to carry out an esterification reaction. Next, the temperature was raised to 255 ° C, the pressure of the reaction system was gradually reduced, and then 30 mm under a reduced pressure of 0.2 mmHg.
A minute reaction was performed to obtain a polyester polyol. The resulting polyester polyol (A-6) was light yellow and transparent and had a reduced viscosity of 0.2. The composition measured by NMR and the like was as follows.

Dicarboxylic acid component terephthalic acid 49 mol% isophthalic acid 48 mol% 5-sodium sulfoisophthalic acid 3 mol% diol component neopentyl glycol 50 mol% ethylene glycol 50 mol% 100 parts of the obtained polyester polyol is stirred with a thermometer. Toluene 10 in a reactor equipped with a heating machine and a reflux condenser
After being charged and dissolved together with 0 part, neopentyl glycol 3
Parts, 15 parts of isophorone diisocyanate, and 0.02 parts of dibutyltin laurate were charged and reacted at 160 to 220 ° C. for 8 hours. The reduced viscosity of the obtained polyurethane resin was 0.
It was 55. After drying the obtained polyurethane under reduced pressure, 34 parts of polyurethane and 10.8 parts of ethylene glycol-n-butyl ether were charged into a container, and the mixture was kept at 150 to 170 ° C for 2 hours.
After stirring for an hour to obtain a uniform and viscous solution, 55.2 parts of water was added with vigorous stirring, and 1 hour later, a uniform pale blue-white aqueous dispersion (C-16) was obtained. The obtained water dispersion was applied onto a glass plate so that the solid film thickness was 15 μm, and the redispersibility was evaluated in the same manner as in Example 1. The redispersibility rank was 1.

Examples 12 to 13 To 100 solid parts of each of the aqueous dispersions (C-1) and (C-2), 25 solid parts of melamine resin (Sumimar M30W, manufactured by Sumitomo Chemical Co., Ltd.) and para Toluenesulfonic acid (catalyst) 0.25 solid parts, titanium oxide 100 parts, glass beads 2
A mixture of 50 parts was shaken and dispersed with a paint shaker for 5 hours. Then, the film thickness after drying on the zinc iron plate is 15μ
The coating film was applied so as to have a thickness of m and baked at 230 ° C. for 1 minute to form a cured coating film. The performance of the obtained cured coating film is shown in Table 4.

Comparative Example 8 (Polyurethane molecular weight ↓ ...
・ Mechanical properties ↓) 100 parts of polyester polyol (A-3) was added to 100 parts of toluene in a reactor equipped with a thermometer, a stirrer, and a reflux condenser.
1 part neopentyl glycol,
5 parts of isophorone diisocyanate and 0.02 part of dibutyltin laurate were charged and reacted at 160 to 220 ° C. for 4 hours. The reduced viscosity of the obtained polyurethane resin was 0.30. The obtained polyurethane was water-dispersed in the same manner as in Example 1. The resulting water dispersion (C-19) was white and had an average particle size of 100 nm and a B-type viscosity at 25 ° C. of 10.
It was 0 cps. A coating material and a coating film were obtained in the same manner as in Example 8 using this water dispersion. The performance of the obtained cured coating film is shown in Table 6.

Comparative Example 9 (Aliphatic polyurethane ...
・ Water resistance ×) In a reactor equipped with a thermometer, stirrer, and reflux condenser,
After 100 parts of polylite 688 and 100 parts of toluene were charged and dissolved, 5 parts of glycerin monoallyl ether, 15 parts of isophorone diisocyanate and 0.02 part of dibutyltin laurate were charged and reacted at 160 to 220 ° C. for 6 hours. The reduced viscosity of the obtained polyurethane resin was 0.55. The obtained polyurethane was water-dispersed in the same manner as in Example 1. The resulting water dispersion (C-20) was white and had an average particle size of 100 nm and a B-type viscosity at 25 ° C. of 10.
It was 0 cps. A coating material and a coating film were obtained in the same manner as in Example 8 using this water dispersion. The performance of the obtained cured coating film is shown in Table 6.

[0092]

[Table 3]

[0093]

[Table 4]

[0094]

[Table 5]

[0095]

[Table 6]

The invention of the present application is as described above, but the summary of the invention of the present application is as follows. A graft polymer obtained by graft-polymerizing a radical-polymerizable monomer containing a hydrophilic group-containing radical-polymerizable monomer into a polyurethane resin containing a polyester polyol as a constituent is water or an organic solvent having water solubility with water. A polyurethane resin-based water dispersion dispersed in a mixed solvent,
The above graft polymer is dispersed in fine particles having an average particle diameter of 500 nm or less, and the half value width of the signal of carbon of the carbonyl group of the polyester polyol in the ¹³ C-NMR spectrum of the fine particles is 300 Hz or more. Water dispersion.

The polyurethane resin does not dissolve or disperse in water by itself, and the polymerizable unsaturated group-containing dicarboxylic acid or the polymerizable unsaturated group-containing diol is added to the total acid component or the total polyol component at 0.5. ~ 10 mol% is a polyurethane resin containing a polyester polyol obtained by copolymerization as a constituent component, the hydrophilic group of the hydrophilic group-containing radically polymerizable monomer is a carboxyl group, the carboxyl group in the graft polymer The polyurethane resin-based water dispersion according to claim 1, wherein at least a part of the above is neutralized with a basic compound.

Polyurethane resin-based water dispersion in which the fine particles of the graft polymer are a polyurethane resin containing a polyester polyol in the core portion and the polyester polyol of the above 1 in which the shell portion forms a core-shell structure of a graft polymer chain as a constituent component. .

The above polyurethane resin-based water dispersion wherein the graft chain of the graft polymer is composed of two or more kinds of radically polymerizable monomers having a copolymerization reactivity ratio to diethyl fumarate in the range of 1 to 12. body.

The polyurethane resin-based aqueous dispersion according to the above 2, wherein the graft chain of the graft polymer is an alternating copolymer of an electron-accepting radical-polymerizable monomer and an electron-donating radical-polymerizable monomer.

Polyurethane resin and carboxyl group containing a polyester polyol obtained by copolymerizing a polymerizable unsaturated group-containing dicarboxylic acid component or a polymerizable unsaturated group-containing polyol component in an amount of 0.5 to 10 mol based on all acid components or all polyol components as a constituent component A radically polymerizable monomer containing a radically polymerizable monomer, a water-soluble organic solvent in a good solvent of the polyurethane resin and a poor solvent of the polyurethane resin of the polymer chain of the radically polymerizable monomer A polyurethane resin obtained by reacting in a mixed solution with a good solvent to obtain a graft polymer, and then neutralizing the graft polymer with a basic compound and dispersing it in water or a mixed solvent of water and a water-soluble organic solvent. Method for producing a system dispersion.

[0102]

The aqueous dispersion of the polyurethane resin of the present invention is excellent in redispersibility, and the coating resin composition produced therefrom has a coating film having an appearance, when coated on metal or plastic.
It has excellent workability and excellent water resistance. Therefore, it is useful for paints, inks, coating agents, adhesives, and various processing agents.

[Brief description of drawings]

FIG. 1 125 MHz of a representative water dispersion of the present invention (Example 5).
It is a figure which shows a ¹³ C-NMR spectrum.

FIG. 2 125M of a representative water dispersion of the invention (Example 11).
It is a figure which shows a Hz ¹³ C-NMR spectrum.

Front page continuation (72) Inventor Yuko Akutomo 1-1-1, Katata, Otsu City, Shiga Prefecture Toyobo Co., Ltd.

Claims (4)

[Claims] 1. A graft polymer obtained by graft-polymerizing a radical-polymerizable monomer containing a hydrophilic group-containing radical-polymerizable monomer onto a polyurethane resin containing a polyester polyol as a constituent is water or water-soluble. A polyurethane resin-based aqueous dispersion dispersed in a mixed solvent with an organic solvent, wherein the graft polymer is dispersed in fine particles having an average particle diameter of 500 nm or less, and the ¹³ C-NMR spectrum of the fine particles is obtained. FWHM of carbon signal of carbonyl group of polyester polyol in
A polyurethane resin-based water dispersion with a frequency of Hz or higher. 2. A polyurethane resin does not dissolve or disperse in water by itself, and a polymerizable unsaturated group-containing dicarboxylic acid or a polymerizable unsaturated group-containing diol is added to all acid components or all polyol components. Is a polyurethane resin containing a polyester polyol obtained by copolymerizing 0.5 to 10 mol% as a constituent component, and the hydrophilic group of the hydrophilic group-containing radically polymerizable monomer is a carboxyl group. The polyurethane resin-based aqueous dispersion according to claim 1, wherein at least a part of the carboxyl groups is neutralized with a basic compound. 3. A polyurethane resin system containing the polyester polyol as a constituent component according to claim 1, wherein the fine particles of the graft polymer form a polyurethane resin containing a polyester polyol in the core portion and the shell portion forms a core-shell structure of a graft polymer chain. Water dispersion. 4. A polyurethane resin containing, as a constituent, a polyester polyol in which 0.5 to 10 mol of a polymerizable unsaturated group-containing dicarboxylic acid component or a polymerizable unsaturated group-containing polyol component is copolymerized with respect to all acid components or all polyol components. A radical-polymerizable monomer containing a carboxyl-group-containing radical-polymerizable monomer, a polymer of the radical-polymerizable monomer in a good solvent of the polyurethane resin in a water-soluble organic solvent and a poor solvent of the polyurethane resin After reacting in a mixed solution with a good chain solvent to obtain a graft polymer, the graft polymer is neutralized with a basic compound and dispersed in water or a mixed solvent of water and a water-soluble organic solvent. Method for producing polyurethane resin-based dispersion.