JP3517821B2 - Aqueous resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an aqueous resin composition having water solubility or water dispersibility and capable of forming a cured film having excellent water resistance.

[0002]

2. Description of the Related Art Heretofore, polymers containing blocked isocyanate groups have been known. This blocked isocyanate group-containing polymer is usually subjected to heat treatment to regenerate active isocyanate groups to form a film having a three-dimensional network structure or to modify other resins having active hydrogen. It is known. Further, since the isocyanate group is protected, it can be used in an aqueous system and can be liquefied with an active hydrogen-containing compound. As a blocking agent for thermally dissociating such a polymer containing a blocked isocyanate group at a relatively low temperature, a sulfite or bisulfite adduct, an oxime system, ε-caprolactam and the like have been conventionally used.

[0003]

By the way, when the polymer containing a blocked isocyanate group is used in an aqueous system, the system containing the polymer containing a blocked isocyanate group is water-soluble or water-soluble. In order to have dispersibility, it is necessary to introduce another hydrophilic comonomer or use a surfactant together in the polymerization treatment. But,
The introduction of other hydrophilic comonomers and the combined use of surfactants, etc.
It becomes a factor that adversely affects the obtained film such as a decrease in water resistance.

Further, in the acrylic type, British Patent 1322
971 proposes a water-soluble homopolymer of an isocyanate group-containing (meth) acrylate blocked with bisulfite and a copolymer with a sulfonic acid group-containing (meth) acrylate. However, any of the above homopolymers and copolymers is merely used as an aqueous crosslinking agent.

Therefore, the object of the present invention is to provide an aqueous resin composition having water solubility or water dispersibility and capable of forming a cured film excellent in water resistance, particularly a self-crosslinking aqueous resin composition. And

[0006]

In order to solve the above problems, the aqueous resin composition of the present invention comprises a vinyl monomer (A) containing an isocyanate group blocked as a sulfurous acid or bisulfite adduct, and an isocyanate. A polymer obtained by polymerizing an ethylenically unsaturated compound (B) containing an active hydrogen group having reactivity with a group, or
The vinyl monomer (A) and the ethylenically unsaturated compound
(B) and other ethylenically unsaturated compound (C)
Including a polymer obtained by polymerizing
The mer (A) is represented by the formula 2 (wherein R is a hydrogen atom or methyl
Represents a group, and X is a linear or branched chain having 2 to 6 carbon atoms
Represents a divalent alkyl group of M is a hydrogen atom or an alkali
Indicates a metal. ) It is characterized by being a compound shown .

[0007]

[0008]

[0009]

[Chemical 2]

The aqueous resin composition is a self-crosslinking aqueous resin composition.

Further, the invention is characterized in that an aqueous paint or a fiber treating agent is synthesized from the aqueous resin composition.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

[0013]

Sulfurous acid used in the aqueous resin composition of the present invention
Iso-blocked as acid or bisulfite adduct
The vinyl monomer (A) containing a cyanate group is
(However, R represents a hydrogen atom or a methyl group, and X represents carbon.
A number of 2 to 6 linear or branched divalent alkyl groups
And M represents a hydrogen atom or an alkali metal. )
As specific examples, 2-isocyanatoethyl (meth) acrylate, 3-isocyanatopropyl (meth)
Acrylate, 2-isocyanato-1-methylethyl (meth) acrylate, 2-isocyanato-1,1-dimethylethyl (meth) acrylate, 4-isocyanatocyclohexyl (meth) acrylate Ru mentioned.
Among these, 2-isocyanatoethyl methacrylate is particularly preferable from the viewpoints of fat solubility in an organic solvent and curability of a cured film obtained by heat-treating a synthesized aqueous resin composition. The vinyl monomer (A) containing an isocyanate group blocked as a sulfurous acid or hydrogen sulfite adduct can be used alone or in combination of two or more.

NaHSO ₃ and KHSO ₃ are preferable as the sulfurous acid or hydrogen sulfite, and bisulfite salts such as Na ₂ S ₂ O ₅ and K ₂ S ₂ O ₅ can also be used synthetically.

As a method for synthesizing a vinyl monomer (A) containing an isocyanate group blocked as a sulfite or bisulfite adduct, an isocyanate group-containing (meth) acrylate blocked as a sulfite or bisulfite adduct, A known method is used. Specifically, a method is preferred in which an aqueous mixed solution of an aqueous solution of bisulfite and a hydrophilic organic solvent such as dioxane is prepared and reacted with an isocyanate group-containing (meth) acrylate while keeping it at a low temperature. Here, the reaction solution can be directly used for the subsequent polymerization, but since a urea compound may be produced by the reaction of an isocyanate group and water and adversely affect the subsequent polymerization, acetone or the like may be used after the reaction. It is more preferable to isolate and purify using a poor solvent of.

The ethylenically unsaturated compound (B) containing an active hydrogen group reactive with an isocyanate group of the present invention includes a hydroxyl group capable of reacting with an isocyanate group, an amino group (aminoethyl (meth) acrylate, N
-Methylpropyl (meth) acrylate), a carboxyl group, an amide group, or an active methylene group-containing monomer, and these may be used alone or in combination of two or more. In particular, a monomer having a hydroxyl group is preferable in view of reactivity with an isocyanate group and physical properties of a cured film obtained by heat-treating an aqueous resin composition to be synthesized. Specific examples of the ethylenically unsaturated compound having a hydroxyl group that is reactive with the isocyanate group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. Derived from hydroxyalkyl (meth) acrylates, hydroxyalkyl (meth) acrylamides such as 2-hydroxypropyl (meth) acrylamide, N-methylol (meth) acrylamide, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. Examples thereof include polyether (meth) acrylates having a hydroxyl group at the terminal and (meth) acrylates derived from polyester polyols and polycarbonate polyols. The ethylenically unsaturated compound (B) containing an active hydrogen group having reactivity with these isocyanate groups is one kind or 2
More than one type can be used at the same time.

Other ethylenically unsaturated compounds (C)
As, methyl (meth) acrylate, ethyl (meth)
Acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, cyclohexyl (meth)
Acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, 2-perfluorooctylethyl methacrylate Such as perfluoroalkyl (meth) acrylate, glycidyl methacrylate, N, N
-Dimethylaminoethyl (meth) acrylate, acrylonitrile, acrylamide, N-substituted acrylamide, (meth) acrylic acid, vinyl acetate, N-vinylacetamide, styrene, α-methylstyrene, etc. It is appropriately selected according to the required physical properties. These other ethylenically unsaturated compounds (C) can be used either individually or in combination of two or more.

A vinyl monomer (A) containing an isocyanate group blocked as a sulfurous acid or hydrogen sulfite adduct, an ethylenically unsaturated compound (B) containing an active hydrogen group reactive with the isocyanate group, and the like. The blending ratio with the ethylenically unsaturated compound (C) is 1 to 95% by weight of the vinyl monomer (A) containing an isocyanate group blocked as a sulfite or bisulfite adduct, based on the total amount thereof. %, 0.5 to 40% by weight of the ethylenically unsaturated compound (B) containing an active hydrogen group having reactivity with an isocyanate group, and the molar ratio of the active hydrogen group to the isocyanate group is 1.0 or less. Is preferred. When the vinyl monomer (A) containing an isocyanate group blocked as a sulfite or bisulfite adduct is less than 1% by weight based on the whole, the water solubility or water dispersibility of the aqueous resin obtained by polymerization is insufficient. In addition, when the total amount is 95% by weight, the water resistance of the cured film obtained by the heat treatment becomes insufficient.

Vinyl monomers (A) containing isocyanate groups blocked as sulfite or bisulfite adducts, ethylenically unsaturated compounds (B) containing active hydrogen groups reactive with isocyanate groups and other ethylene. As a method for polymerizing the polyunsaturated compound (C), for example, a known radical polymerization method is preferably used. As the radical polymerization method, either a solution polymerization method or a suspension polymerization method can be used. Specifically, a predetermined amount of each monomer is copolymerized in the presence of a radical polymerization initiator in an aqueous solvent.

As the solvent, an organic solvent such as acetone, methyl ethyl ketone, isopropanol, methyl cellosolve, butyl cellosolve, etc. which is mixed with water at an arbitrary ratio may be used in combination. As the radical polymerization initiator, a water-soluble azo compound such as azobisisobutyroamidine hydrochloride or a water-soluble radical generating compound such as ammonium persulfate, potassium persulfate or hydrogen peroxide can be preferably used, and its addition The amount is 0.1 per 100 parts of monomer
An appropriate amount is about 10 parts.

The preferred number average molecular weight of the aqueous resin composition obtained by this polymerization treatment is 5,000 to 100,
It is 000. The molecular weight of the aqueous resin composition can be adjusted by adding a chain transfer agent such as mercaptoacetate to the polymerization system. Further, the preferred solid content concentration of the aqueous resin composition obtained by the polymerization treatment is 10 to 6
It is 0% by weight.

The synthesized aqueous resin composition is a self-crosslinking aqueous resin composition. As a method of self-crosslinking, generally, after molding or coating an aqueous resin composition, the mixture is allowed to stand in a heating atmosphere at room temperature to 200 ° C. without pressurization to obtain a polymerization initiator such as an organic peroxide. A method of causing a cross-linking reaction in a non-added state is used. This makes 3
A three-dimensional network structure is formed to form a water resistant film.

Specifically, when the synthesized aqueous resin composition is self-crosslinked to be used as an aqueous paint or an aqueous fiber treating agent, this aqueous resin composition is applied to a target substrate and then dried by heating. To remove water, then raise the temperature,
It is preferable to use a method of heating and curing the aqueous resin composition. The temperature for heating and drying is room temperature to 100 ° C.
Is preferable, and the temperature at the time of heat curing is 130
The temperature is preferably ~ 200 ° C.

As described above, the aqueous resin composition of the present invention is
It does not require any other hydrophilic comonomer or surfactant during the polymerization treatment, has self-crosslinking properties, and has excellent water solubility or water dispersibility due to the sulfite or bisulfite salt which is a blocking agent.

Further, since no hydrophilic group remains in the cured film obtained by heat-treating this synthesized aqueous resin composition, excellent water resistance can be obtained. Accordingly, the aqueous resin composition of the present invention can be suitably applied as various coating agents such as aqueous paints, fiber treatment agents, various resin modifiers, binders, adhesives and the like.

[0027]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited to these examples.

In this example, the mixing ratio of each component of Examples 1 to 5 and Comparative Example 1 and Comparative Example 2 of the aqueous resin composition of the present invention, and the film formed by the aqueous resin composition Water resistance and water repellency are shown in Table 1.

[0029]

[Table 1]

The evaluation method of water resistance and water repellency is as follows.
It is as follows.

(Evaluation method of water resistance) A water-based resin composition was applied to a glass plate, dried at 80 ° C, and then dried at 150 ° C for 30 minutes.
The film formed by baking for one minute was immersed in water at room temperature for 7 days, and the appearance of this film was visually evaluated. Good: No change Poor: Change in film, swelling or whitening

(Evaluation method of water repellency) A cotton cloth was impregnated with an aqueous resin composition, dried at 80 ° C, and then dried at 150 ° C for 30 minutes.
After baking for a minute, a spray test of JIS-L1092 was performed, and the wet state of the surface was visually evaluated. Good: No or partial adherence to surface, poor: Poor surface shows wetness

First, a block monomer a, which is a vinyl monomer (A) containing an isocyanate group blocked as a sulfurous acid or bisulfite adduct of the present invention,
A method of synthesizing b and c will be described.

(Synthesis Method of Block Monomer a) In a glass flask equipped with a stirrer and a dropping funnel, 34.13 g of 2-isocyanatoethyl methacrylate (Karenz MOI Showa Denko KK) and 0.03 g of p-methoxyphenol were placed. Was charged and cooled to 0 ° C. Into the dropping funnel, 20.8 g of sodium hydrogen sulfite was added to ion-exchanged water 4
An aqueous solution prepared by dissolving 20.0 g of dioxane dissolved in 8.5 g was added, and the mixture was added dropwise over 1 hour while maintaining the liquid temperature at 0 to 10 ° C. Then, the reaction was further continued for 1 hour. Next, the reaction solution was added to 1.5 liter of acetone to precipitate a solid, and a white powder of the block monomer a was obtained.

(Synthesis Method of Block Monomer b) A glass flask equipped with a stirrer and a dropping funnel was charged with 31.0 g of 2-isocyanatoethyl acrylate and 0.03 g of p-methoxyphenol and cooled to 0 ° C. An aqueous solution prepared by dissolving 20.8 g of sodium bisulfite in 48.5 g of ion-exchanged water and mixing 20.0 g of dioxane was put into the dropping funnel and added dropwise over 1 hour while keeping the liquid temperature at 0 to 10 ° C. . Then, the reaction was further continued for 1 hour. Next, the reaction solution was added to 1.5 liter of acetone to precipitate a solid, and a white powder of the block monomer b was obtained.

(Synthesis Method of Block Monomer c) A glass flask equipped with a stirrer and a dropping funnel was charged with 34.1 g of 2-isocyanatopropyl acrylate and 0.03 g of p-methoxyphenol and cooled to 0 ° C.
An aqueous solution prepared by dissolving 20.8 g of sodium bisulfite in 48.5 g of ion-exchanged water and mixing 20.0 g of dioxane was put into the dropping funnel and added dropwise over 1 hour while keeping the liquid temperature at 0 to 10 ° C. . Then, the reaction was further continued for 1 hour. Next, the reaction liquid was added into 1.5 liter of acetone to precipitate a solid, and a white powder of the block monomer c was obtained.

Next, the method of synthesizing the aqueous resin compositions of Examples 1 to 5 and the test results will be described.

HEMA (2-hydroxyethyl methacrylate) was used as the ethylenically unsaturated compound (B) containing an active hydrogen group having reactivity with an isocyanate group, and another ethylenically unsaturated compound (C) was used. , Rf-MA (2-perfluorooctylethyl methacrylate) or nBA (butyl acrylate) was used.

Example 1 A glass flask equipped with a stirrer, a gas introduction tube, a reflux condenser and a thermometer was charged with 400 g of ion-exchanged water, 50 g of a block monomer a, 20 g of 2-hydroxyethyl methacrylate and 30 g of butyl acrylate, and nitrogen was added. The temperature was raised to 50 ° C under an air stream.
Next, 1.0 g of ammonium persulfate was added to ion-exchanged water 5
An aqueous solution dissolved in g was added. At this time, heat generation due to the initiation of polymerization was observed, and after this heat generation, the temperature was kept at 80 ° C for 2 hours.
Polymerization was completed to obtain a dispersion of the aqueous resin composition. The amount of aggregates (resin particles remaining in the net when filtered through a 100-mesh net) contained in the dispersion of the aqueous resin composition was 0.1 g or less, and the precipitate was formed even when left at room temperature for 3 months. Was not observed and was stable, and the water dispersibility was good. Further, the film formed from this aqueous resin composition was transparent and hard, and showed excellent water resistance.

(Example 2) The aqueous resin composition of Example 2 was also synthesized at the compounding ratio shown in Table 1 in the same manner as the method for synthesizing the aqueous resin composition of Example 1. Thereby, a water-soluble aqueous resin composition was obtained. The film formed from this water-based resin composition was transparent and hard and showed excellent water resistance.

(Examples 3 to 5) The aqueous resin compositions of Examples 3 to 5 were also synthesized at the compounding ratios shown in Table 1 in the same manner as in the method of synthesizing the aqueous resin composition of Example 1. did. As a result, dispersions of the aqueous resin composition were obtained. These aqueous resin compositions also have almost no aggregates,
The water dispersibility was good. Further, the film formed from these aqueous resin compositions was transparent and hard, and showed excellent water resistance and water repellency.

Next, Comparative Examples 1 and 2 will be described.

Comparative Example 1 In Comparative Example 1, the block resin d obtained by reacting methylethylketoxime and 2-isocyanatoethylmethacrylate was used at the blending ratio shown in Table 1, and the aqueous resin composition of Example 1 was used. A polymer was obtained by the same synthetic method as described in 1. The obtained polymer was not dispersible in water and became a lump.

Comparative Example 2 In Comparative Example 2, 1.2 g of polyoxyethylene alkyl ether as a surfactant was further added to each monomer of Comparative Example 1, and the same synthetic method as in Example 1 was used. To obtain a polymer. This polymer was an emulsion having good water dispersibility. The film formed by this polymer was opaque and had poor water resistance.

[0045]

As described above, the aqueous resin composition of the present invention has reactivity with a vinyl monomer (A) containing an isocyanate group blocked as a sulfite or bisulfite adduct, and the isocyanate group. By polymerizing an ethylenically unsaturated compound (B) containing an active hydrogen group and, if necessary, another ethylenically unsaturated compound (C) to synthesize, thereby obtaining another hydrophilic comonomer during the polymerization treatment. Since the isocyanate group is blocked with a hydrophilic sulfurous acid or bisulfite without requiring a surfactant or the like, excellent water solubility or water dispersibility can be obtained.

Further, by coating the base material with this aqueous resin composition and subjecting it to heat treatment, sulfurous acid or bisulfite is removed, and the regenerated isocyanate group is recombined with the active hydrogen group, so that it is excellent in water resistance. A hardened film is obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-165419 (JP, A) JP-A-6-206979 (JP, A) UK patent application publication 1322971 (GB, A) (58) Research field (Int.Cl. ⁷ , DB name) C08G 18/00-18/87 C08F 220/34-220/36

Claims (4)

(57) [Claims] 1. A vinyl monomer (A) containing an isocyanate group blocked as a sulfite or bisulfite adduct, and an ethylenically unsaturated compound (B) containing an active hydrogen group reactive with an isocyanate group. Polymer obtained by polymerizing the above , or the vinyl monomer
(A), the ethylenically unsaturated compound (B), and
Obtained by polymerizing with another ethylenically unsaturated compound (C)
Include are polymers, the vinyl monomer (A) is of
1 (provided that R represents a hydrogen atom or a methyl group, and X represents carbon)
Linear or branched divalent alkyl group having 2 to 6 primes
And M represents a hydrogen atom or an alkali metal. )so
An aqueous resin composition, which is a compound shown . [Chemical 1] 2. The water-based resin composition is a self-crosslinking water-based resin.
An aqueous composition according to claim 1, which is a fat composition.
Resin composition. 3. The aqueous tree according to claim 1 or 2.
A water-based paint comprising a fat composition. 4. The aqueous tree according to claim 1 or 2.
A fiber treatment agent comprising a fat composition.