JP2002012729A - Water soluble resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water soluble resin composition excellent in hydrophilic nature, durability, stability and non-odor, and suitable for a hydrophilic treat ment. SOLUTION: There is provided a water-soluble resin composition comprising a copolymer, obtained by copolymerizing (A) 10-50 wt.% of a hydrophilic vinyl monomer represented by formula (1): (wherein R1 is a hydrogen atom or methyl group; R2 is an alkyl, phenyl or substituted phenyl group; (x) is 2 or 3; and (q) is an integer of 1 or more), (B) 5-40 wt.% of a hydroxylated vinyl monomer, (C) 5-30 wt.% of a carboxylated vinyl monomer and (D) 10-40 wt.% of other vinyl monomer copolymerizable with these, and an organometallic complex.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-soluble resin composition useful for hydrophilic treatment of heat exchanger fins used in a heat exchanger of an air conditioner.

[0002]

2. Description of the Related Art In a heat exchanger of an air conditioner, condensed water generated during cooling becomes water droplets, and forms a water bridge between aluminum fins (hereinafter abbreviated as fins) for a heat exchanger to narrow an air passage. Therefore, ventilation resistance increases, and problems such as loss of power, generation of noise, and scattering of water droplets occur.

In order to prevent such a phenomenon, the surface of the fin is made hydrophilic to prevent water droplets and the formation of bridges due to the water droplets.

[0004] As a method for performing the surface hydrophilic treatment of such a heat exchanger, an aluminum plate is formed and processed to form fins, and after assembling the fins, a surface treating agent (hydrophilic, rustproof) is immersed and sprayed. , After-coating method of applying by means such as shower, and pre-coating method of forming fins by forming a surface treatment film on an aluminum plate in advance by means such as a roll coater and then press-forming this plate. is there. In the former, a method for making the surface of a fin hydrophilic has been put to practical use. (1) A method of applying a water glass represented by the general formula mNa ₂ O · nSiO ₂ (for example, JP-A-59-13078) And (2) a method of applying a solution mainly composed of an organic polymer resin such as a water-soluble polyamide resin to form a resin film (for example, JP-A-61-250495), and (3) A solution containing an organic-inorganic composite reactant having a dispersed inorganic silica fine powder as a core, a polymerizable unsaturated monomer reacted as a nucleus as a main component, and further containing a curing agent and a water-soluble polyamide resin is applied. (For example, JP-A-3-269073).
Furthermore, in order to provide a comfortable living space, generation of odor has recently been regarded as a problem. Further, as a countermeasure against the initial coating odor and the unpleasant odor caused by microorganisms generated in the air conditioner (at the start of operation), use of a coating agent mixed with a bactericidal agent and a preservative has been proposed (Japanese Patent Application Laid-Open (JP-A) no. JP-A-58-10051, JP-A-61-168675, etc.).

The method using water glass disclosed in JP-A-59-13078 shows good hydrophilicity persistence with a water droplet contact angle of 20 ° or less. Has a problem in that it becomes powdery and scatters when ventilated to produce a cement odor or a chemical odor. The method of applying a solution mainly composed of an organic polymer resin such as a water-soluble polyamide resin disclosed in Japanese Patent Application Laid-Open No. 61-250459 can sufficiently satisfy various characteristics even if it is put to practical use. However, there is a problem in terms of corrosiveness of the processing plate, odor, stability of the processing liquid, and the like.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a water-soluble resin composition which is excellent in hydrophilicity, durability, stability and odor and which is suitable for a hydrophilic treatment.

[0007]

That is, the present invention provides a compound represented by the following general formula (1):

[0008]

Embedded image (Where R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group, a phenyl group or a substituted phenyl group, and x
Is 2 or 3, and q is an integer of 1 or more), (B) 5 to 40% by weight of a vinyl monomer having a hydroxyl group, and (C) a carboxyl group. 5 to 30% by weight of vinyl monomer and (D) another vinyl monomer copolymerizable therewith
It is intended to provide a copolymer obtained by copolymerizing 0 to 40% by weight and a water-soluble resin composition containing an organometallic complex.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The copolymer used in the present invention is obtained by copolymerizing the vinyl monomers (A), (B), (C) and (D).

In the hydrophilic vinyl monomer (A) represented by the general formula (1) used in the present invention, R ² has 1 carbon atom such as a methyl group, an ethyl group or a propyl group.
~ 15 alkyl groups, phenyl groups and methylphenyl groups,
Examples include a substituted phenyl group having an alkyl group having 1 to 9 carbon atoms such as an ethylphenyl group as a substituent (the overall preferable number of carbon atoms is 7 to 15). Further, q is represented by R ² ,
It is an integer of 1 or more, preferably 2 to 30 appropriately determined. In order to obtain sufficient water solubility, it is preferable to increase q as the number of carbon atoms in R ² increases. Examples thereof include methoxy polyethylene glycol monomethacrylate, methoxy polyethylene glycol monoacrylate, phenoxy polyethylene glycol monomethacrylate, nonylphenoxy polyethylene glycol monomethacrylate, and the like. R ² has 1 to 1 carbon atoms
Ten are preferred. When R ² is a methyl group, q is 4
As described above, when R ² is a substituted phenyl group (eg, a halogen atom, an alkyl group, or the like is used as the substituent), q is preferably 6 or more because a suitable water solubility can be obtained. One type of hydrophilic vinyl monomer may be used alone, or 2
More than one species may be used in combination. The used amount is 10 to 50% by weight based on all monomers, and it is preferable to use 20 to 40% by weight in order to balance durability and hydrophilicity of the coating film. If the amount used is less than 10% by weight, the hydrophilicity of the coating film is inferior, and if it exceeds 50% by weight, the strength of the coating film is reduced and the durability is inferior.

(B) The vinyl monomer having a hydroxyl group is preferably a vinyl monomer having one hydroxyl group.
For example, hydroxyalkyl esters of acrylic or methacrylic acid, such as hydroxyethyl acrylate,
Preferred are hydroxy C ₂ -C ₄ alkyl esters of acrylic acid or methacrylic acid such as hydroxyisopropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxyisopropyl methacrylate and hydroxybutyl methacrylate. The vinyl monomer having a hydroxyl group is used in an amount of 5 to 40% by weight based on all monomers,
It is preferably used in an amount of up to 35% by weight. If it is less than 5% by weight, the hydrophilicity of the coating film is inferior. If it exceeds 40% by weight, the strength of the coating film is reduced and the durability is inferior. The vinyl monomer having a hydroxyl group may be used alone or in combination of two or more.

(C) The vinyl monomer having a carboxyl group is preferably a vinyl monomer having one carboxyl group, and examples thereof include unsaturated carboxylic acids such as acrylic acid and methacrylic acid.
The amount of the vinyl monomer having a carboxyl group to be used is 5 to 30% by weight, preferably 10 to 20% by weight, based on all monomers. If the amount is less than 5% by weight, sufficient coating film durability cannot be obtained, and if it exceeds 30% by weight, the viscosity during the monomer copolymerization becomes so severe that synthesis fails. The vinyl monomer having a carboxyl group is 1
These are used alone or in combination of two or more.

In order to improve the physical properties of the coating film, another vinyl monomer is copolymerized with the above monomer as (D). As other copolymerizable vinyl monomers, for example, the following can be used.

(A) Esters of acrylic acid or methacrylic acid, for example, alkyl acrylates
Methyl acrylate, ethyl acrylate, acrylic acid n-
Propyl, isopropyl acrylate, n-butyl acrylate, tert-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, cetyl acrylate, stearyl acrylate, and the like.Examples of methacrylates include Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, cetyl methacrylate, methacrylic acid Stearyl and the like.

(B) Vinyl aromatic compounds: for example, vinyl aromatic compounds having 8 to 12 carbon atoms, for example, styrene,
Vinyltoluene, α-methylstyrene and the like.

(C) Reactive vinyl monomers:
Methacryloxypropyltrimethoxysilane, methacryloxypropylmethyldimethoxysilane, methacryloxypropyldimethylmethoxysilane, methacryloxypropyltriethoxysilane, methacryloxypropylmethyldiethoxysilane, methacryloxypropyldimethylmethoxysilane and the like.

These vinyl monomers can be used alone or in combination of two or more. The use amount of these is determined by the use amount of the above (A) to (C), but is usually 10 to 40% by weight based on all monomers.
It is. If the amount is less than 10% by weight, the obtained copolymer will have poor coating film strength, and if it exceeds 40% by weight, the hydrophilicity will be reduced, and the resulting copolymer will have poor antifogging properties.

In the present invention, the glass transition temperature (Tg) of the obtained copolymer is preferably from -50 ° C to 30 ° C, more preferably from -30 ° C to 20 ° C, and particularly preferably from -20 ° C to 10 ° C. It is. Here, when Tg is lower than −50 ° C., a problem is apt to occur in the strength and durability of the coating film.
If the ratio exceeds the above range, the water-solubilizing component is reduced due to the composition thereof, which may cause a problem in hydrophilicity. In the present invention, the above Tg means a theoretical glass transition point calculated by the following equation (however, Tg in the following equation is an absolute temperature).

1 / Tg = Σ (wi / Tgi) where wi is the weight% of each vinyl monomer and Tg
i is the Tg (unit: absolute temperature) of the homopolymer of each vinyl monomer. Therefore, Tg can be adjusted by the type and the mixing ratio of the vinyl monomer to be mixed.

The copolymerization of the vinyl monomer may be carried out, if necessary, using an organic solvent such as methanol, ethanol, isopropanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carbitol, carbitol, butyl carbitol or water as a reaction solvent or dilution. Can be used as a solvent.

Examples of the polymerization initiator include peroxide radical polymerization initiators such as benzoyl peroxide and ditertiary butyl peroxide, and azo radicals such as 2,2'-azobisisobutyronitrile and azobisvaleronitrile. A system radical polymerization initiator, ammonium peroxodisulfate, or the like can be used.

The polymerization is preferably carried out simply by solution polymerization, but suspension polymerization, bulk polymerization, ionic polymerization, photopolymerization, radiation polymerization and the like can also be used.

The weight average molecular weight of the obtained copolymer (obtained by gel permeation chromatography using a calibration curve prepared with standard polystyrene) is 1.
It is preferably from 000 to 100,000, and particularly preferably from 20,000 to 60,000. If the weight average molecular weight is less than 10,000, problems tend to occur in the strength and durability of the coating film. If the weight average molecular weight exceeds 100,000, the viscosity of the resin solution increases, so that problems in workability tend to occur. The molecular weight can be adjusted by appropriately selecting the amount, type, and polymerization temperature of the polymerization initiator.

The copolymer thus obtained is contained as a main component in the water-soluble resin composition of the present invention.

As the organometallic complex to be incorporated in the copolymer, aluminum chelates and titanium chelates are preferable. For example, as the aluminum chelates, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate), alkyl acetoacetate aluminum dimethyl Isopropylate, aluminum monoacetylacetonate bis (ethylacetoacetate), aluminum tris (acetylacetonate), and titanium chelate such as tetrastearyloxytitanium, di-i-propoxybis (acetylacetonato) titanium, -N-butoxybis (triethanolaminonato) titanium, titanium-i-propoxyoctylene glycolate, titanium stearate and the like are preferred. That. The amount of the organometallic complex to be used is preferably carboxyl group / organometallic complex = 1 / 0.1 to 1 / 1.2 (molar ratio) with respect to the vinyl monomer having a carboxyl group which is a raw material monomer of the copolymer. , 1 / 0.5 to 1/1.
If the amount of the organometallic complex is less than 0.1, the curability of the coating film tends to be insufficient and the durability tends to be inferior, and if it exceeds 1.2, the unreacted organometallic complex increases and decreases the water resistance of the coating film. There is a tendency. The compounding amount of the organometallic complex with respect to the copolymer is (weight of the copolymer) ×
(% By weight of carboxyl group-containing monomer in the copolymer)
/ (Molecular weight of carboxyl group-containing monomer) × (molecular weight of organometallic complex) × (molar ratio of organometallic complex).

The water-soluble resin composition of the present invention may contain other known resins and curing agents to such an extent that the good hydrophilicity of the copolymer is not impaired.

Further, if necessary, various known antibacterial agents can be blended.

The water-soluble resin composition of the present invention obtained as described above is used as a hydrophilizing agent, as an intermediate coating for improving the adhesion of a top coating, and for preventing clouding due to water vapor. As an anti-fog coating, metal, applied to various objects to be coated such as glass, according to a known method,
The substrate can be subjected to a hydrophilic treatment.

The base material used in the present invention includes metals such as aluminum, iron and copper, glass, plastics and the like.
Various types can be used, and the shape is not particularly limited. However, when used for hydrophilizing aluminum fins for a heat exchanger, fins having excellent durability and odor can be obtained.

When the water-soluble resin composition is applied to a substrate, the water-soluble resin composition is usually dissolved in a solvent and applied as a solution. As the solvent, for example, water, an alcohol-based solvent, a cellosolve-based solvent, and the like are suitably used.

In order to improve the solvent solubility of the obtained water-soluble resin composition, a part or all of the carboxyl groups of the copolymer may be neutralized. When the neutralization treatment is performed, at the end of the vinyl monomer copolymerization, ammonia, triethylamine, sodium hydroxide, potassium hydroxide or the like is used, usually at 20 ° C to 100 ° C for 10 minutes to 2 hours, preferably 30 minutes to 1 hour. Let react.

[0032]

Next, the present invention will be described by way of examples. “Parts” and “%” indicate “parts by weight” and “% by weight”, respectively.

Copolymer Solution Synthesis Example 1 Methoxypolyethylene glycol monomethacrylate FA-400M (manufactured by Hitachi Chemical Co., Ltd.) was placed in a four-necked flask equipped with a thermometer, a reflux condenser, a stirrer, and a nitrogen gas inlet. 110 parts were charged with q = 9 in the general formula (1), 20 parts of R ¹ and R ² methyl groups) and 50 parts of butyl cellosolve.
The temperature was raised to ° C. Under a nitrogen gas flow, FA-400M20
Parts, 30 parts of hydroxyethyl acrylate, 10 parts of methacrylic acid, 20 parts of methyl methacrylate, and 2,2 '
A mixture of 0.8 parts of -azobisisobutyronitrile was added dropwise over 2 hours, and the mixture was further kept at the same temperature for 1 hour, and then 20 parts of butyl cellosolve and 0.2 parts of 2,2'-azobisisobutyronitrile were added. Eight parts of the mixture were added dropwise over 30 minutes. Thereafter, the temperature was raised to 130 ° C., and the reaction was carried out so that the degree of polymerization became 99.9% or more, whereby a copolymer solution was synthesized. Thereafter, methanol was added to adjust the copolymer solution to about 40% solid content. Table 1 shows the heating residue, viscosity, glass transition point (Tg), and weight average molecular weight of the obtained copolymer solution.

Copolymer Solution Synthesis Example 2 In a four-necked flask equipped with a thermometer, a reflux condenser, a stirrer, and a nitrogen gas inlet, methoxypolyethylene glycol monomethacrylate FA-400M (manufactured by Hitachi Chemical Co., Ltd.) 110 parts were charged with 15 parts of q = 9, R ¹ and R ² methyl groups in the general formula (1) and 50 parts of butyl cellosolve.
The temperature was raised to ° C. Under a nitrogen gas flow, FA-400M20
A mixture of 10 parts, 10 parts of hydroxyethyl acrylate, 20 parts of methacrylic acid, 15 parts of methyl methacrylate, 20 parts of butyl acrylate and 1.0 part of 2,2'-azobisisobutyronitrile was dropped over 2 hours, After keeping the temperature at the same temperature for 1 hour, a mixed solution of 20 parts of butyl cellosolve and 0.8 parts of 2,2'-azobisisobutyronitrile was added dropwise over 30 minutes. Thereafter, the temperature was raised to 130 ° C., and the reaction was carried out so that the degree of polymerization became 99.9% or more, whereby a copolymer solution was synthesized. Thereafter, methanol was added to adjust the copolymer solution to about 40% solid content.

Copolymer Solution Synthesis Example 3 Methoxypolyethylene glycol monomethacrylate FA-400M (manufactured by Hitachi Chemical Co., Ltd.) was placed in a four-necked flask equipped with a thermometer, a reflux condenser, a stirrer, and a nitrogen gas inlet. 110 parts were charged with q = 9 in the general formula (1), 20 parts of R ¹ and R ² methyl groups) and 50 parts of butyl cellosolve.
The temperature was raised to ° C. Under a nitrogen gas flow, FA-400M20
Parts, 10 parts of hydroxyethyl acrylate, 20 parts of methacrylic acid, 30 parts of methyl methacrylate, and 2,2 '
A mixture of 1.0 part of -azobisisobutyronitrile was added dropwise over 2 hours. After keeping at the same temperature for 1 hour,
A mixture of 20 parts of butyl cellosolve and 0.8 parts of 2,2'-azobisisobutyronitrile was added dropwise over 30 minutes. Thereafter, the temperature was raised to 130 ° C., and the reaction was carried out until the polymerization rate became 99.9% or more to synthesize a copolymer solution. Thereafter, methanol was added to adjust the copolymer solution to about 40% solids.

Copolymer Solution Synthesis Example 4 A methoxypolyethylene glycol monomethacrylate FA-400M (manufactured by Hitachi Chemical Co., Ltd.) was placed in a four-necked flask equipped with a thermometer, a reflux condenser, a stirrer, and a nitrogen gas inlet. 20 parts of q = 9 in the general formula (1), R ¹ and R ² methyl groups) and 50 parts of butyl cellosolve were charged.
The temperature was raised to ° C. FA-400M20 under nitrogen gas flow
Parts, 30 parts of hydroxyethyl acrylate, 10 parts of methacrylic acid, 5 parts of methacryloxypropylmethyldimethoxysilane, 15 parts of methyl methacrylate, and 2,2 '
-A mixture of 1 part of azobisisobutyronitrile was added dropwise over 30 minutes, and the mixture was further kept at the same temperature for 1 hour. Thereafter, a mixture of 20 parts of butyl cellosolve and 0.8 parts of 2,2'-azobisisobutyronitrile was added dropwise over 30 minutes. At the same temperature, the reaction was carried out so that the degree of polymerization became 99.9% or more, whereby a copolymer solution was synthesized. Thereafter, methanol was added to adjust the copolymer solution to about 40% solid content.

The properties of the copolymer solutions obtained in Copolymer Solution Synthesis Examples 2 to 4 are shown in Table 1 as in Copolymer Solution Synthesis Example 1.

Examples 1 to 3 Resin solution 10 synthesized in the above copolymer solution synthesis examples 1 to 3
g-di-i-propoxy bis (acetylacetonato)
2.5 g of titanium (trade name T-80, manufactured by Nippon Soda) was added to prepare a water-soluble resin composition.

Comparative Examples 1 and 2 The copolymer solution 10 synthesized in the above copolymer synthesis examples 3 and 4
Then, 0.7 g of methanol was added to the resulting mixture to prepare a water-soluble resin composition.

[0040]

[Table 1] Evaluation of hydrophilicity The water-soluble resin compositions obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were applied to a glass plate of 10 cm × 20 cm × 3 mm so as to have a dry film thickness of 1 μm, and were heated at 100 ° C. for 1 hour. After drying, 1 ml of ion-exchanged water was dropped on the surface of the coating film, and the initial contact angle at that time was measured using a contact angle measuring device manufactured by Kyowa Interface Science Co., Ltd. Table 2 shows the results.

[0041]

[Table 2] Evaluation of durability The water-soluble resin compositions obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were applied to a glass plate of 10 cm × 20 cm × 3 mm so as to have a dry film thickness of 1 μm, and were heated at 20 ° C. for 24 hours. Dried. The contact angle after the cycle test was measured by immersing in distilled water at 20 ° C. for 8 hours and drying at 80 ° C. for 16 hours as one cycle. Table 3 shows the results.

[0042]

[Table 3] Evaluation of adhesion to aluminum, appearance of coated surface, and yellowing of coating film An aluminum plate was washed with acetone, and Example 1 was placed thereon.
-3 and Comparative Examples 1-2, the water-soluble resin composition was applied to a dry film thickness of 10 μm, dried at 110 ° C. for 1 hour, and then subjected to a grid test (1 mm square) according to JIS K5400. Table 4 shows the results. Table 4 shows the results of visual judgment of the appearance of the coated surface and the test results of yellowing of the coating film at 200 ° C. for 20 minutes.

[0043]

[Table 4] It was found that the test plates obtained in any of the examples had less odor and were excellent in odor as compared with the case where water glass was applied.

Resin stability test The water-soluble resin compositions obtained in Resin Examples 1 to 3 were
Stored at 0 ° C. for 1 month. Neither solution had any separation or gelation. Paint stability The pot life of each of the water-soluble resin compositions obtained in the above Examples was 12 hours or more.

[0045]

The water-soluble resin composition of the present invention has a contact angle of a very small water droplet, has high stability and durability, and is excellent in adhesion, painted surface appearance, coatability and odor. It is very useful for hydrophilizing aluminum fins for heat exchangers.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F28F 13/18 F28F 13/18 B // C09D 5/00 C09D 5/00 Z 133/04 133/04 171 / 02 171/02 F term (reference) 4J002 BC021 BG011 BG041 BG051 BG071 EC076 EH016 EN106 FD206 GH00 4J027 AC01 AC02 AC03 AC06 BA02 BA06 BA07 BA08 BA10 BA12 CA28 CB03 CC02 CD08 4J038 CC061 CC071 CC081 CG03 CH031 001 KA06 MA09 MA13 MA14 NA06 NA25 NA27 PC02 PC03 PC08 4J100 AB02S AB03S AB04S AJ02R AL03S AL04S AL05S AL08P AL08S AL09Q BA02P BA04P BA08P BA77S CA06 JA01 JA43

Claims (1)

[Claims] (A) The following general formula (1): (Where R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group, a phenyl group or a substituted phenyl group, and x
Is 2 or 3, and q is an integer of 1 or more), (B) 5 to 40% by weight of a vinyl monomer having a hydroxyl group, and (C) a carboxyl group. 5 to 30% by weight of vinyl monomer and (D) another vinyl monomer copolymerizable therewith
A water-soluble resin composition containing a copolymer obtained by copolymerizing 0 to 40% by weight and an organometallic complex.