JPH07166031A - One-pack curable aqueous emulsion composition - Google Patents

Abstract

PURPOSE:To obtain a composition improved in adhesion, water resistance, heat resistance, solvent resistance, etc., by mixing a specified epoxy-modified acrylic emulsion with a curing agent for epoxy resin and ammonium zinc carbonate. CONSTITUTION:100 pts.wt. (in terms of the solids content) epoxy-modified acrylic emulsion having a glass transition temperature (Tg) of -30 to 30 deg.C and having a core/shell structure in which the core comprises a copolymer of an aromatic vinyl monomer, an unsaturated carboxylic ester monomer, an amido acrylic monomer and an epoxy resin and having a Tg of -30 to 80 deg.C and the shell comprises a copolymer comprising an aromatic vinyl monomer, a hydroxy acrylic monomer, an amido acrylic monomer and a carboxylic acrylic monomer and having a Tg of -60 to 30 deg.C is mixed with 1-30 pts.wt. curing agent for epoxy resin and 0.05-5 pts.wt. ammonium zinc carbonate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-component curable emulsion composition having excellent adhesive strength, water resistance, heat resistance, solvent resistance and the like when cured at room temperature or by heat curing. Specifically, adhesives, adhesives that require adhesiveness, water resistance, heat resistance, solvent resistance, bending resistance, etc., granular, powdery or fibrous inorganic or wood fiber binders, architectural paints, anticorrosive paints Base resin of
Further, it is used as a binder for paper processing, fiber processing and the like.

[0002]

2. Description of the Related Art Conventionally, adhesives in these fields include formalin condensation resins represented by urea resins, melamine resins and phenol resins, one- or two-liquid solvent type synthetic rubbers, polyurethane resins, epoxy resins, Polyester resins and one- or two-component vinyl acetate emulsions, acrylic emulsions, synthetic rubber latexes, aqueous emulsions such as urethane dispersions and epoxy resin dispersions have been used.

[0003]

Of the above resins, the formalin condensation type resins require equipment such as cold pressure or hot pressure press, and are mainly used for panel adhesives produced in factories. And toxicity is a problem. Solvent-based resins are becoming pollution-free due to recent problems of environmental pollution, adverse effects on human bodies, fires, etc., and there is a gradual shift to pollution-free resins. In addition, although an aqueous emulsion is non-polluting and does not cause problems such as environmental pollution, there is a limit with one liquid in order to obtain high adhesive strength, water resistance, heat resistance, etc., and a curing agent or curing accelerator, etc. It is necessary to use the two-component type in combination, and there are problems such as the complexity of the compounding work, the restriction on the pot life of the two-component compound, and the adhesion failure due to a measurement error during compounding. In order to solve these two-component problems,
A one-component aqueous acrylic urethane emulsion having a crosslinking ability between emulsion particles by a dehydration reaction of a carbonyl group and a hydrazide group has been introduced, but it lacks water resistance and heat resistance.

[0004]

Means for Solving the Problems The present inventor
As a result of repeated studies for the purpose of solving problems such as adverse effects on the human body and fire, and imparting adhesive strength, water resistance, heat resistance, solvent resistance, etc. with a one-component aqueous emulsion, a hybrid of epoxy resin and acrylic emulsion It was found that the modified emulsion was effective. That is, after forming an emulsion particle in which an epoxy resin is copolymerized with an aromatic vinyl monomer, an unsaturated carboxylic acid ester monomer and an acrylic monomer having an amide group, the outer side is continuously subjected to an aromatic vinyl monomer and an unsaturated carboxylic acid. A glass transition temperature of −30 obtained by copolymerizing an ester monomer, a hydroxyl group-containing acrylic monomer, an amide group-containing acrylic monomer and a carboxyl group-containing acrylic monomer.
An epoxy-modified acrylic emulsion having a so-called core-shell structure of ~ + 30 ° C is excellent in stability such as viscosity change during long-term storage. The emulsion is mixed with a curing agent for epoxy resin represented by amine and polyamide. This stability is also firmly adhered to, and by further adding zinc ammonium carbonate, it was found that water resistance is remarkably improved, especially in adhesive properties such as adhesive strength, water resistance, heat resistance, and solvent resistance. Has been completed.

That is, the present invention is as follows. 1. The core layer is a copolymer of an aromatic vinyl-based monomer, an unsaturated carboxylic acid ester monomer, an amide group-containing acrylic monomer and an epoxy resin, and the shell layer is an aromatic vinyl-based monomer, an unsaturated carboxylic acid ester monomer, and a hydroxyl group. Solid content of epoxy modified acrylic emulsion (a) having a core-shell structure, which is a copolymer of an acrylic monomer, an amide group-containing acrylic monomer and a carboxyl group-containing acrylic monomer.
A one-component curable aqueous emulsion comprising 100 parts by weight of the epoxy resin curing agent (b) as a solid content of 1 to 30 parts by weight and zinc ammonium carbonate (c) as a solid content of 0.05 to 5 parts by weight. Composition. 2. The epoxy-modified acrylic emulsion (a) is obtained by copolymerizing 1 to 30 parts by weight of an epoxy resin in 100 parts by weight of the solid content of the emulsion. The one-component curable aqueous emulsion composition described. 3. The glass transition temperature (Tg) of the epoxy modified acrylic emulsion (a) is in the range of -30 to + 30 ° C. The one-component curable aqueous emulsion composition described. 4. The epoxy-modified acrylic emulsion (a) is characterized in that the core layer has a glass transition temperature (Tg) of −30 to + 80 ° C. and the shell layer has a glass transition temperature (Tg) of −60 to + 30 ° C. 1. The one-component curable aqueous emulsion composition described.

The epoxy-modified acrylic emulsion (a) having a core-shell structure of the present invention (hereinafter abbreviated as EPAE) can be obtained by the following method. First, a mixed monomer prepared by dissolving an epoxy resin in various monomers such as an aromatic vinyl monomer and an unsaturated carboxylic acid ester monomer is gradually added to a surfactant-prepared distilled water prepared at room temperature while stirring. , Making so-called pre-emulsifying monomers. Then, a flask equipped with a stirrer and a condenser was charged with distilled water and a surfactant, and the atmosphere was replaced with nitrogen.
After the temperature was raised to 0 ° C., a polymerization initiator was administered, the pre-emulsified monomer was added dropwise over a certain period of time, and after the addition was completed, at the same temperature,
By reacting the residual monomer, emulsion particles serving as the core of the present invention are formed. Subsequently, various monomers used in advance in the shell layer were prepared as emulsion monomers in the same manner as in the case of the core layer, and the mixture was dropped into the flask over a certain period of time, and the residual monomer was treated and polymerized to obtain the core. The EPAE having a so-called core-shell structure coated with particles is emulsion-polymerized. After completion of the reaction, the temperature is cooled to 40 ° C. or lower, the pH is adjusted to 6 to 9 with aqueous ammonia, and the mixture is filtered through a 100 mesh wire mesh to obtain EPAE used in the present invention.

Aromatic vinyl monomers used for emulsion polymerization of EPAE of the present invention include styrene, α-methylstyrene and divinylbenzene, and unsaturated carboxylic acid esters include methylmethacrylate, ethylmethacrylate, isobutylmethacrylate and tert. Acrylic acid or methacrylic acid ester having an alkyl group having 4 to 12 carbon atoms such as butyl methacrylate, vinyl acetate, acrylonitrile, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, 2 ethylhexyl acrylate, 2 ethylhexyl methacrylate and lauryl methacrylate. Among them, a combination of styrene and n-butyl acrylate is preferable from the viewpoint of economy and ease of emulsion polymerization.

Examples of the monomer having an amide group include acrylamide, methacrylamide, maleimide, N-methylol acrylamide, N-methylol methacrylamide, N-methoxymethyl acrylamide, N-isopropoxymethyl acrylamide, N-butoxymethyl acrylamide and N-iso Examples thereof include butoxymethyl acrylamide, N-octyloxymethyl acrylamide, N-carboxymethylene oxymethyl acrylamide and the like. Among them, methacrylamide or N-methylol methacrylamide is preferable from the viewpoint of adhesive strength, water resistance, warm water resistance and the like. As the monomer having a carboxyl group, acrylic acid, methacrylic acid, itaconic acid, maleic acid,
Fumaric acid and the like can be mentioned, among which stability during emulsion polymerization,
Acrylic acid or methacrylic acid is preferred from the viewpoint of mechanical and chemical stability. Examples of the monomer having a hydroxyl group include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate and the like, and among them, hydroxyethyl methacrylate is preferable because of stability after compounding with a curing agent for epoxy resin.

The epoxy resin is a bis-epi type consisting of bisphenol A type and epichlorohydrin, a cyclic fatty acid type consisting of a cyclic fatty acid unsaturated compound and peracetic acid, a novolak type consisting of a phenol resin and epichlorohydrin,
Tetraepoxy type consisting of glyoxal and phenol and epichlorohydrin, polybutadiene type consisting of polybutadiene and peracetic acid, halogenated type consisting of halogenated bisphenol A and epichlorohydrin, side chain type consisting of bisphenol A and epichlorohydrin and propylene oxide, and other polyalkylene ether type , Ester type, methyl substitution type and the like. Among these, due to the emulsion copolymerizability with the above-mentioned monomer, bisphenol A-
An epichlorohydrin type resin is particularly suitable, for example, an epoxy resin having an epoxy equivalent of 180 to 270 and a viscosity of 5 to 150 poise is preferable.

The copolymerization ratio of the epoxy resin in the solid content of 100 parts by weight of EPAE is in the range of 1 to 30 parts by weight. That is, it means that the above epoxy resin is used for the emulsion core layer. It is preferably in the range of 5 to 20 parts by weight. If it is less than 1 part by weight, the adhesive strength, water resistance, warm water resistance, heat resistance, solvent resistance and the like will be insufficient, and if it is more than 30 parts by weight, stability will not be obtained during emulsion polymerization of the core layer, It causes manufacturing problems.

The glass transition temperature (hereinafter abbreviated as Tg) of the EPAE of the present invention is in the range of -30 to + 30 ° C.
More preferably, it is in the range of -20 to + 20 ° C. -30
When the temperature is lower than ℃, the adhesive strength and heat resistance are lacking, and when the temperature is higher than +30 ° C, there is no problem under the condition of heating and curing, but the film forming property at room temperature is poor, and the adhesive strength, water resistance and heat resistance are obtained. Absent. Incidentally, the Tg expressed in the present invention means a calculated value from all monomers except the epoxy resin. The TAE of the core layer of the EPAE of the present invention is in the range of -30 to + 80 ° C, preferably -10 to + 60 ° C. When the temperature is lower than -30 ° C, the adhesive strength and heat resistance cannot be obtained, and when the temperature is higher than + 80 ° C, the film-forming property at room temperature is insufficient, and the adhesive strength and the water resistance are deteriorated. Similarly, the Tg of the shell layer is −60 to + 30 ° C., more preferably −40 to + 20 ° C. When the temperature is lower than -60 ° C, the adhesive strength and heat resistance are insufficient, and when the temperature is higher than + 30 ° C, the film-forming property at room temperature is insufficient and sufficient adhesive strength and water resistance cannot be obtained.

The weight ratio of the monomers used in the core layer and the shell layer of EPAE is not particularly limited, but the preferred core-shell composition ratio is in the range of 7/3 to 3/7. When the amount of monomer used in the core layer is increased to 7/3 or more, there is a risk that the core is not completely covered,
Stability during storage is affected.

Examples of the curing agent (b) for epoxy resin include aromatic amines, aliphatic amines, heterocyclic modified amines, amines such as polyamides, thiochols such as polysulfides, and acid anhydrides. Of these, although not particularly limited, those that can be freely diluted with water or those that can be emulsified with water are preferable because of ease of formulation and stability during storage. Is.

The mixing ratio of the epoxy resin curing agent is EP
1 to 100 parts by weight of the solid content of AE as a solid content
30 parts by weight, more preferably 5 to 15 parts by weight. When the amount is less than 1 part by weight, the dry coating of EPAE does not proceed with curing and the adhesive strength, water resistance, heat resistance, solvent resistance and the like are not sufficiently exhibited, and when the amount is more than 30 parts by weight, the odor of the adhesive agent, It is a problem that yellowing, reduction of solid content, and excess epoxy curing agent exhibit a plasticizing effect, which lowers adhesive strength, heat resistance and the like.

The compounding ratio of zinc ammonium carbonate is EP
The amount is 0.05 to 5 parts by weight, preferably 0.1 to 0.5 parts by weight, based on 100 parts by weight of the solid content of AE. The mechanism for improving the water resistance by blending zinc ammonium carbonate is E
It is presumed that it is based on metal chelation with the carboxyl group used for PAE. If less than 0.05 parts by weight,
No significant improvement in water resistance was observed, and when the amount was more than 5 parts by weight, the effect of improving water resistance was in a saturated region, and the solid content of the one-pack curable emulsion was reduced due to the fact that it was blended as a low-concentration aqueous solution. This is a practical problem.

As described above, a one-component curable aqueous emulsion comprising the EPAE of the present invention in which a curing agent for an epoxy resin and zinc ammonium carbonate are mixed, a carboxyl group which reacts with a glycidyl group coexists in emulsion particles, and water is used. Despite the fact that the layer contains a curing agent for epoxy resin such as amine, it has excellent long-term storage stability due to the particles having a shape in which the glycidyl group is protected by the shell layer.
It exhibits high adhesive strength, water resistance, heat resistance, solvent resistance, bending resistance, etc. at room temperature or heat curing, and since it is further compounded with zinc ammonium carbonate, especially water resistance is further improved.
It has high practical value as an adhesive, a granular, powdery or fibrous inorganic or wood fiber binder, a paint for construction, a base resin for rust preventive paint, and a binder for paper processing, fiber processing and the like. The present one-component curable aqueous emulsion is a thickener, a dispersant, a defoaming agent film-forming aid, water, an organic solvent, a plasticizer, a colorant, an antifreezing agent, and a PH, as long as the desired effect is not impaired.
You may use together a regulator, a silane coupling agent, etc.

[0017]

EXAMPLES The present invention will be described below with reference to production examples, examples and comparative examples, but the invention is not limited thereto. In the examples, parts and percentages are by weight unless otherwise specified.

Examples 1 to 9 Mixing modules for core and shell layers having the composition ratios shown in Table 1
A mixture of 100 parts of Nomer and chain transfer agent was weighed in advance and
50 parts distilled water, sodium dodecylbenzene sulfonate
Dropped into 0.5 parts under stirring to prepare a pre-emulsified monomer
It was Separately, 100 parts of distilled water and dode
Nitrogen was charged with 0.2 part of sodium silbenzene sulfonate.
After heating to 70 ° C with stirring under a seal, 0.5 part of excess
N-butyl acetate should be used as seed for potassium sulfate and emulsion.
Crylate and methyl methacrylate and hydroxy ether
Mixed monomers of 1: 1: 1 ratio of chill methacrylate
-Prepare 0.5 parts and let react for 20 minutes emulsion particles
Nuclei were formed. Next, the pre-emulsified product for the core
Mar is continuously dripped over 3 hours, and after the dropping is complete, the remaining
The nomer was reacted. Continue to use emulsion monomers for shells
It dripped over 3 hours like the above. After the dropping, raise the temperature to 80 ° C
The residual monomer reaction for 1 hour and then potassium persulfate
Dissolve 0.2 parts with 10 parts water and add 25% ammonia water
Add an aqueous solution with pH adjusted to 8-9, and then add at the same temperature.
After polymerizing the remaining monomer for 2 hours, cool it to below 40 ° C.
Adjusted to pH7 with ammonia water, EPA with solid content of 50%
I got E. Percentage shown in Table-1 for 100 parts of this EPAE
Of epoxy resin curing agent and zinc ammonium carbonate
After the combination, it is filtered with a 100 mesh wire mesh to cure the one-part curing of the present invention.
A type aqueous emulsion was obtained. This one-component curing type aqueous emulsion
100 g / m on a 3 mm thick calcareous plate ²Average
0.5m thickness which was applied to one and cut into 5x5cm square beforehand
m steel plates were pasted together. Heat the bonded product to 100 ° C
It was dried in an air dryer for 10 minutes and aged at room temperature for 24 hours.
After bonding with the sample, it was aged at room temperature for 24 hours
Two kinds of samples were prepared and subjected to the following adhesion test.

1) Storage stability The one-component curable aqueous emulsions obtained in Examples 1 to 30 were used.
It was stored in a constant temperature bath at ℃, and displayed as the number of days required until the viscosity doubled from the initial value or abnormalities such as gelation occurred. 2) Adhesion Test 2-1) Normal Adhesion Force Using a Kenken-type tensile tester, each sample aged for 24 hours was subjected to a plane tensile test, and the adhesive force was expressed in Kg / cm ² and shown in Table 2. . 2-2) Water-resistant adhesive strength The cured sample was immersed in city water at 20 ° C. for 24 hours and immediately subjected to a test in accordance with the normal-state adhesive strength in a wet normal state, and the results are shown in Table 2 by the same method. . 2-3) Heat-resistant adhesive strength The sample after curing is left to stand in a hot air dryer at 80 ° C. for 168 hours,
Immediately after taking out, it was subjected to a test in accordance with the normal adhesive strength, and the results are shown in Table 2 by the same method. 2-4) Warm-water-resistant adhesive strength The test after curing is immersed in warm water at 60 ° C. for 24 hours, taken out, and then tested in a wet state, and then subjected to a test according to the normal-state adhesive strength. The results are shown in Table-2.

[0020]

[Table 1]

[0021]

[Table 2]

Comparative Example 1 The core and shell layer monomers used in Example 1 were mixed and E was prepared according to the same emulsion polymerization method as in the core layer of Example 1.
A PAE was prepared, the same curing agent for epoxy resin as in Example 1 was blended, and the mixture was subjected to the same test as in Example 1 and the results are also shown in Table 2.

Comparative Example 2 The same test as in Example 1 was carried out except that the curing agent for epoxy resin was removed from Example 1, and the results are also shown in Table 2.

Comparative Example 3 Using only the core layer monomer used in Example 1, the amount of distilled water in the initial charge was reduced and an EPAE having a solid content of 50% was prepared according to the same emulsion polymerization method as in the core layer of Example 1. Then, the same epoxy resin curing agent as in Example 1 was blended and subjected to the same test as in Example 1, and the results are also shown in Table 2.

Comparative Example 4 Using the core layer monomer used in Example 1 and the shell layer monomer of Example 8, an EPAE was prepared according to the same emulsion polymerization method as in Example 1 and the same as in Example 1 below. The epoxy resin curing agent was mixed and subjected to the same test as in Example 1, and the results are also shown in Table 2.

Comparative Example 5 Using the core layer monomer used in Example 8 and the shell layer monomer used in Example 1, an EPAE was prepared according to the same emulsion polymerization method as in Example 1, and the following Example 1 was used. The same curing agent for epoxy resin was blended and subjected to the same test as in Example 1, and the results are also shown in Table-2.

Examples 10 to 18 As shown in Table 3, titanium white was mixed with water and an aqueous solution of 5% sodium pyrophosphate and uniformly dispersed using three rolls to prepare a titanium white slurry. This slurry was sampled in a 500 cc poly cup, and stirred with a stirrer to prepare Examples 1-9.
The one-component curable aqueous emulsion used in 1. was mixed homogeneously, then 6 g of ethylene glycol and 6 g of butyl carbitol as antifreezing agents and film forming aids, and 0.1 g of Nopco 8034 as an antifoaming agent were mixed, and a 300 mesh wire mesh An aqueous emulsion type paint was prepared by filtration. Apply this paint to 0.
50 g / m ² using a 3 mm thick steel plate with an applicator
Was evenly applied. This coated steel sheet was dried with a hot air dryer at 100 ° C for 20 minutes and then cured at room temperature for 24 hours, and two kinds of coated samples with different drying conditions, which were cured at room temperature for 72 hours, were prepared and subjected to the following test. The results are shown in Table-4.

1) Storage stability: The aqueous emulsion paints of Examples 10 to 18 were stored in a constant temperature bath at 30 ° C., and the number of days until the initial viscosity changed more than twice or the abnormality such as gelation occurred was checked. Then displayed. 2) Water resistance: Immediately after curing, it was immersed in city water at 20 ° C. for 24 hours, and a test of scratching the same place with a nail was performed 5 times, and the state of the coating film was displayed as shown below. ○ The coating film is not scratched, and no abnormalities such as peeling phenomenon are observed. △ The coating film is slightly scratched but does not peel off. × The coating film was peeled from the steel plate surface after 1 to 2 scratch tests. 3) Solvent resistance: Immersed in toluene immediately after curing for 24 hours, dried in a 100 ° C dryer for 30 minutes, cooled, and then eluted from the initial sample weight and the weight change after drying the immersed product to elute the coating film. Amounts are expressed in%. Comparative Examples 6 to 10 As shown in Table 3, using the aqueous emulsions used in Comparative Examples 1 to 5, aqueous emulsion paints were prepared according to Example 10, and the same test as in Example 10 was performed to show the results. -4.

[0029]

[Table 3]

[0030]

[Table 4]

[0031]

As is clear from Tables 2 and 4, in the one-component curable aqueous emulsion of the present invention, a carboxyl group that reacts with a glycidyl group coexists in the emulsion particles, and the aqueous layer is like an amine. Despite the fact that the curing agent for epoxy resin is blended, the glycidyl group has a shape protected by the shell layer, so it has excellent long-term storage stability, and has a high adhesive strength when cured at room temperature or by heating. Since it has water resistance, heat resistance, solvent resistance, bending resistance, etc., it is used as a base resin for adhesives, granular, powdered or fibrous inorganic or wood fiber binders, architectural paints, and anticorrosive paints. Moreover, it has high practical value as a binder for paper processing, fiber processing, etc.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C09J 163/08 JFP

Claims (4)

[Claims] 1. A core layer is a copolymer of an aromatic vinyl monomer, an unsaturated carboxylic acid ester monomer, an amide group-containing acrylic monomer and an epoxy resin, and a shell layer is an aromatic vinyl monomer, an unsaturated carboxylic acid ester. For the epoxy resin, 100 parts by weight of the solid content of the epoxy modified acrylic emulsion (a) having a core-shell structure, which is a copolymer of a monomer, an acrylic monomer having a hydroxyl group, an acrylic monomer having an amide group and an acrylic monomer having a carboxyl group, A one-part curable aqueous emulsion composition comprising 1 to 30 parts by weight of a curing agent (b) as a solid content and 0.05 to 5 parts by weight of a zinc ammonium carbonate (c) as a solid content. 2. An epoxy modified acrylic emulsion (a).
Is a copolymer of 1 to 30 parts by weight of an epoxy resin in 100 parts by weight of the solid content of the emulsion, and the one-part curable aqueous emulsion composition according to claim 1. 3. An epoxy modified acrylic emulsion (a).
The glass transition temperature (Tg) of the above is in the range of -30 to + 30 ° C, and the one-part curable aqueous emulsion composition according to claim 1. 4. An epoxy modified acrylic emulsion (a).
Glass transition temperature (Tg) of the core layer of -30 to +80
° C, the glass transition temperature (Tg) of the shell layer is -60 to +3
The one-part curable aqueous emulsion composition according to claim 1, which is in the range of 0 ° C.