JP2010143955A - Water-dispersible resin composition forming film exhibiting water resistance and solvent resistance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-dispersible resin composition that forms a film excellent in water resistance and solvent resistance without using a curing agent. <P>SOLUTION: The water-dispersible resin composition is composed mainly of a water-dispersible polyester resin (A) having copolymerized an ester-forming sulfonic acid alkali metal salt compound as a dicarboxylic acid component and having copolymerized diethylene glycol as a diglycol component and an acrylic resin (B) having copolymerized a glycidyl group-containing radically polymerizable unsaturated monomer, wherein a resin solids content ratio by weight of (A) and (B), (A)/(B), is (10-80)/(90-20). <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention relates to a water-dispersible resin composition that forms a water-resistant and solvent-resistant film, and more specifically, a water-dispersible resin composition that forms a water- and solvent-resistant film without using a curing agent. About.
The present invention is used for surface protection of non-solvent-resistant substrates such as ABS, acrylic and polycarbonate, binders such as paper and plastic films, coating materials and adhesives for substrates such as metal and glass, printing inks and conductive polymers. The present invention relates to a water-dispersible resin composition that can be used for applications, laminated films, resins for easy-adhesive coating films, resins for paints, and the like.

  In recent years, environmental regulations have become stricter, and a shift from solvent-based processing agents to water-based processing agents is progressing. However, water-based processing agents are inferior in water resistance and solvent resistance compared to solvent-based processing agents.

  If the water-dispersible resin composition has strong hydrophilicity, the solvent resistance is excellent but the water resistance is poor.If the hydrophilicity is weak, the water resistance is excellent but the solvent resistance is poor. It is very difficult to achieve both compatibility and solvent resistance.

  Applications that require solvent resistance include surface protection of non-solvent resistant substrates such as ABS, acrylic, polycarbonate, and the like. When solvent-based paints are applied directly to these substrates, the surface is covered with aromatic solvents such as toluene and xylene, ketone solvents such as acetone and methyl ethyl ketone, and ester solvents such as ethyl acetate and butyl acetate. As a result, the appearance of the substrate is impaired. Therefore, it is required to protect the surface of the solvent-based paint from being damaged by applying a water-based primer in advance.

By the way, as a means for improving the water resistance and solvent resistance of the water-dispersible resin composition, a method of using a curing agent in combination has been proposed. (For example, see Patent Documents 1, 2, 3, 4, and 5)
However, since this composition is a two-component type, it is necessary to mix the main agent and the curing agent before use. After mixing, the two react to increase the viscosity of the solution. There is a problem that workability is poor.
Japanese Unexamined Patent Publication No. 01-207374 Japanese Patent Laid-Open No. 04-318091 JP 09-011427 A Japanese Patent Laid-Open No. 11-124539 JP 2003-301274 A

Further, as an example of a laminated film layer containing a polyester excellent in handling properties based on solvent resistance, a copolymerized polyester containing isophthalic acid and diethylene glycol as copolymerization components is known. Here, for example, it is said that the solvent resistance of the C layer against alcohol can be improved by copolymerizing diethylene glycol.
Further, a magnetic recording medium having an undercoat layer made of a copolyester resin that is excellent in solubility in organic solvents and solution stability and that exhibits a solvent resistance is also known. (For example, see Patent Document 7)
However, even though these polyester resin laminated films have excellent solvent resistance to alcohol, they are not resistant to aromatic solvents such as toluene and xylene, and ketone solvents such as acetone and methyl ethyl ketone. In order to improve the solvent resistance, it is required to use a crosslinking agent such as a polyisocyanate compound, an epoxy resin, or a melamine resin.
JP 2004-216877 A JP 2001-118240 A

  Conventionally, a water-dispersible resin composition has a problem that it is inferior in water resistance and solvent resistance, and the object of the present invention is a water-dispersible resin that forms a film excellent in water resistance and solvent resistance without using a curing agent. It is to provide a composition. Furthermore, the film is excellent in transparency and adhesion to a plastic substrate.

  As a result of intensive studies to solve the above problems, the present invention has been achieved. That is, the composition of the present invention comprises a water-dispersible polyester resin (A) in which an ester-forming sulfonic acid alkali metal salt compound is copolymerized as a dicarboxylic acid component and diethylene glycol is copolymerized as a diglycol component, and a glycidyl group-containing radical polymerization. The main component is an acrylic resin (B) copolymerized with a polymerizable unsaturated monomer, and the resin solid content weight ratio between (A) and (B) is (A) / (B) = 10-80 / 90- It is a water-dispersible resin composition that forms a film having water resistance and solvent resistance, characterized in that it is 20.

  The water-dispersible polyester resin (A) in the present invention is composed of an aromatic dicarboxylic acid and an ester-forming alkali metal salt compound as a dicarboxylic acid component as a copolymer component, and all of the ester-forming alkali metal salt compound is formed. It is characterized by containing 6 to 20 mol% in the acid component.

  Moreover, in this invention, 20-80 mol% of diethylene glycol is contained in all glycol components as a diglycol component which is a copolymerization component of water-dispersible polyester resin (A), It is characterized by the above-mentioned.

  Furthermore, in the present invention, the copolymerization monomer of the acrylic resin (B) is characterized by containing 10 to 100% by weight of the glycidyl group-containing radical polymerizable unsaturated monomer in all monomers.

  The water-dispersible resin composition of the present invention forms a film excellent in both water resistance and solvent resistance, and the film is also excellent in transparency. Moreover, since this resin composition is aqueous and does not require the use of a curing agent, it is easy to handle and has excellent adhesion to a plastic substrate.

The water-dispersible polyester resin (A) of the present invention will be described.
The dicarboxylic acid component that is a copolymerization component of the water-dispersible polyester resin (A) of the present invention contains an ester-forming sulfonic acid alkali metal salt compound as an essential component, and includes phthalic acid, terephthalic acid, dimethyl terephthalate, isophthalic acid, and isophthalic acid. Aromatic dicarboxylic acids such as dimethyl, 2,5-dimethylterephthalic acid, 2,6-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, orthophthalic acid, fats such as succinic acid, adipic acid, azelaic acid, sebacic acid and dodecanedicarboxylic acid Alicyclic dicarboxylic acids such as cycloaliphatic dicarboxylic acids and cyclohexanedicarboxylic acids.
As the dicarboxylic acid component other than the ester-forming sulfonic acid alkali metal salt compound, an aromatic dicarboxylic acid is preferable, and since the aromatic nucleus of the aromatic dicarboxylic acid has a high affinity with a hydrophobic plastic, adhesion is improved, There is an advantage that it is excellent in degradability. In particular, terephthalic acid and isophthalic acid are preferable.

  The ester-forming sulfonic acid alkali metal salt compound is preferably contained in the total acid component in an amount of 6 to 20 mol%. More preferably, it is 10-18 mol%. When the ester-forming sulfonic acid alkali metal salt compound is less than 6 mol%, the dispersion time of the resin in water becomes long, and the solvent resistance is not sufficient. Conversely, if it exceeds 20 mol%, the water resistance tends to decrease.

  Examples of the ester-forming sulfonic acid alkali metal salt compound include alkali metal salts such as sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfoisophthalic acid, 4-sulfonaphthalenic acid-2,7-dicarboxylic acid (alkali sulfonic acid alkali). Metal salts) and their ester-forming derivatives, and the sodium salt of 5-sulfoisophthalic acid and its ester-forming derivatives are more preferably used.

Examples of the diglycol component that is a copolymerization component of the water-dispersible polyester resin (A) include diethylene glycol and an aliphatic group having 2 to 8 carbon atoms or an alicyclic glycol group having 6 to 12 carbon atoms. Specific examples of the aliphatic having 2 to 8 carbon atoms or the alicyclic glycol having 6 to 12 carbon atoms include ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, Neopentyl glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, 1,6-hexanediol , P-xylylene glycol, triethylene glycol and the like, and one or more of these may be used in combination.
It is preferable to contain 20-80 mol% of diethylene glycol in the total glycol component. Even if diethylene glycol is outside this range, the solvent resistance to alcohol can be obtained, but the solvent resistance is insufficient with respect to aromatic solvents such as toluene and xylene.

  The water-dispersible polyester resin (A) needs a number average molecular weight of 2,000 to 30,000, and a preferred number average molecular weight is 2,500 to 25,000. When the number average molecular weight is less than 2,000, resin physical properties such as water resistance and solvent resistance are deteriorated, and when it exceeds 30,000, only a resin which is difficult to handle due to water dispersibility is obtained.

The water-dispersible polyester resin (A) is produced by a polycondensation reaction after esterification or transesterification of dicarboxylic acid and diglycol by a known production technique, but the production method is limited at all. It is not a thing. That is, the above-described acid component and glycol component are esterified or transesterified at 130 to 200 ° C., and then subjected to a polycondensation reaction at 200 to 250 ° C. under reduced pressure conditions. A) can be obtained.
Examples of the reaction catalyst used at this time include metal acetates such as zinc acetate and manganese acetate, metal oxides such as antimony oxide and germanium oxide, and titanium compounds.

The water-dispersible polyester resin (A) is used by uniformly dispersing water in water containing water or an aqueous solvent under heating and stirring at 50 to 90 ° C. Since the aqueous dispersion obtained in this way is difficult to obtain a uniform dispersion when the solid content concentration becomes high, the polyester solid content concentration is preferably 30% by weight or less.
Specific examples of the aqueous solvent include lower alcohols such as methanol, ethanol, normal propanol, and isopropanol, polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, and glycerin, ethylene glycol monomethyl ether, and ethylene glycol monoethyl. Examples include ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol acetate, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether and the like.

Next, the glycidyl group-containing acrylic resin (B) of the present invention will be described.
The glycidyl group-containing acrylic resin (B) is a homopolymer of a glycidyl group-containing radical polymerizable unsaturated monomer or a glycidyl group-containing radical polymerizable unsaturated monomer and another radical polymerizable unsaturated monomer copolymerizable therewith. It is a copolymerized resin.

The glycidyl group-containing radically polymerizable unsaturated monomer is preferably contained in an amount of 10 to 100% by weight, more preferably 20 to 100% by weight, based on all monomers.
It is considered that the glycidyl group-containing radical polymerizable unsaturated monomer improves water resistance and solvent resistance by advancing internal crosslinking of the glycidyl group-containing acrylic resin (B). In particular, the solvent resistance to ketone solvents such as acetone and methyl ethyl ketone and ester solvents such as ethyl acetate and butyl acetate is remarkable.
Solvent resistance to alcohol can be obtained even if the glycidyl group-containing radical polymerizable unsaturated monomer is less than 10% by weight, but solvent resistance to ketone solvents such as acetone and methyl ethyl ketone, and ester solvents such as ethyl acetate and butyl acetate is poor. It is enough.

  Examples of the glycidyl group-containing radical polymerizable unsaturated monomer include glycidyl ethers such as glycidyl acrylate, glycidyl methacrylate, and allyl glycidyl ether.

  Radical polymerizable unsaturated monomers that can be copolymerized with glycidyl group-containing radical polymerizable unsaturated monomers include vinyl esters, unsaturated carboxylic acid esters, unsaturated carboxylic acid amides, unsaturated nitriles, unsaturated carboxylic acids, allyl compounds, Examples thereof include nitrogen-based vinyl monomers, hydrocarbon vinyl monomers, and vinyl silane compounds.

  Examples of vinyl esters include vinyl propionate, vinyl stearate, higher tertiary vinyl esters, vinyl chloride, and vinyl bromide. Examples of unsaturated carboxylic acid esters include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, butyl maleate, octyl maleate, butyl fumarate, Octyl fumarate, hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, ethylene glycol dimethacrylate, ethylene glycol diacrylate, Examples thereof include polyethylene glycol dimethacrylate and polyethylene glycol diacrylate.

  Examples of unsaturated carboxylic acid amides include acrylamide, methacrylamide, methylol acrylamide, and butoxymethylol acrylamide. An example of the unsaturated nitrile is acrylonitrile.

  Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, maleic acid acidic ester, fumaric acid acidic ester, and itaconic acid acidic ester.

  Examples of the allyl compound include allyl acetate, allyl methacrylate, allyl acrylate, and diallyl itaconate. Examples of the nitrogen-containing vinyl monomer include vinyl pyridine and vinyl imidazole, and examples of the hydrocarbon vinyl monomer include ethylene, propylene, hexene, octene, styrene, vinyl toluene, and butadiene. Examples of the vinylsilane compound include dimethylvinylmethoxysilane, dimethylvinylethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropyldimethoxysilane.

When an unsaturated carboxylic acid such as acrylic acid or methacrylic acid is used as the radical polymerizable unsaturated monomer, the effect of improving the solvent resistance is further exhibited by crosslinking with the glycidyl group.
The unsaturated carboxylic acid monomer is preferably contained in an amount of 5 to 20% by weight in all monomers. If the unsaturated carboxylic acid monomer is less than 5% by weight, the combined effect is not observed, and if it exceeds 20% by weight, the liquid gels with time and the storage stability deteriorates.

The glycidyl group-containing acrylic resin (B) is produced by a known production technique, but the production method is not limited at all. Here, the manufacturing method by emulsion polymerization is described.
For example, ion-exchanged water, a polymerization initiator, and a surfactant are charged into a reaction tank, and then ion-exchanged water and a surfactant are charged into a dropping tank, and monomers are added to prepare an emulsion. Perform the reaction. The reaction temperature is 60 to 100 ° C., and the reaction time is 4 to 10 hours.

As the surfactant used for the emulsion polymerization, a general anionic or nonionic reactive surfactant and a non-reactive surfactant may be used alone or in combination of two or more.
Specific examples of reactive surfactants include anionic surfactants such as alkylallylsulfosuccinate, polyoxyethylene alkylpropenyl phenyl ether sulfate, polyoxyalkylene alkenyl ether sulfate, and (meth) acrylate sulfate. And nonionic surfactants such as polyoxyethylene alkylpropenyl phenyl ether, polyoxyalkylene alkenyl ether, (meth) acrylate sulfate, and the like.
Specific examples of non-reactive surfactants include anionic systems such as alkyl sulfates, alkylbenzene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether disulfonates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl phosphate esters, etc. Nonionic surfactants such as surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene diphenyl ethers, polyoxyethylene fatty acid esters and the like can be mentioned.

  As a polymerization initiator used for emulsion polymerization, a general radical polymerizable initiator, for example, a water-soluble peroxide such as potassium persulfate, ammonium persulfate, hydrogen peroxide, benzoyl peroxide, t-butyl hydroperoxide, or the like Or an azo compound such as azobisisobutyronitrile.

The water-dispersible resin composition of the present invention has a resin solid content weight ratio of the water-dispersible polyester resin (A) and the glycidyl group-containing acrylic resin (B) to (A) / (B) = 10-80 / 90- 20. Preferably, (A) / (B) = 20-70 / 80-30.
When the water-dispersible polyester resin (A) is less than 10% by weight, that is, when the glycidyl group-containing acrylic resin (B) exceeds 90% by weight, the adhesion to the substrate and the transparency of the film are lowered, and the water-dispersible polyester If the resin (A) exceeds 80% by weight, that is, if the glycidyl group-containing acrylic resin (B) is less than 20% by weight, sufficient solvent resistance and water resistance cannot be obtained.

The water-dispersible resin composition of the present invention can be obtained by mixing an aqueous dispersion of a water-dispersible polyester resin (A) and an acrylic emulsion of a glycidyl group-containing acrylic resin (B). Polymerize a radically polymerizable unsaturated monomer containing a glycidyl group alone or another radically polymerizable unsaturated monomer capable of copolymerizing with the radically polymerizable unsaturated monomer containing a glycidyl group in an aqueous dispersion of the resin (A). You can also get it.
In this case, the above-mentioned surfactant and polymerization initiator are used.

  The water-dispersible resin composition of the present invention includes an antifoaming agent, a wetting agent, a surfactant, a thickener, a plasticizer, an antioxidant, an ultraviolet absorber, a preservative, and the like that do not impair the effects of the present invention. Can be added within.

  Examples of the substrate on which the water-dispersible resin composition of the present invention is coated include plastic films such as polyester, polyolefin, polycarbonate, polystyrene, polyvinyl chloride, ABS, and acrylic. Furthermore, it can be applied to a molded article such as paper, fabric such as woven fabric or knitted fabric, nonwoven fabric, metal, wood, ceramic, ceramics, and the like.

Adhesion can be further improved by performing corona discharge treatment, ultraviolet irradiation treatment, etc. before applying the water-dispersible resin composition of the present invention.
As a coating method, various known methods such as a roll coating method, a curtain coating method, a die coating method, a bar coating method, a comma coating method, or a spray coating method can be applied.

  As coating conditions for the water-dispersible resin composition of the present invention, the coating amount is usually 0.1 to 5 μm in film thickness after drying, and as the drying conditions, drying at 80 to 180 ° C. for 30 seconds to 180 seconds is preferable. . Examples of the drying method include known drying methods such as hot air drying, hot roll drying, and infrared drying.

  EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In the text, “parts” and “%” indicate parts by weight or% by weight unless otherwise specified.

Manufacture of water-dispersible polyester resin (A) A four-necked flask equipped with a distilling tube, a nitrogen introducing tube, a thermometer, and a stirrer, 854 parts of dimethyl terephthalate, 355 parts of 5-sodiumsulfoisophthalic acid, 186 parts of ethylene glycol Part, diethylene glycol 742 parts and 1 part of zinc acetate as a reaction catalyst, heated from 130 ° C. to 170 ° C. over 2 hours, transesterified, then added 730 parts of isophthalic acid and 1 part of antimony trioxide Then, the temperature was raised from 170 ° C. to 200 ° C. over 2 hours to carry out an esterification reaction. Subsequently, the temperature was gradually raised and reduced, and finally the polycondensation reaction was carried out at a reaction temperature of 250 ° C. and a degree of vacuum of 5 mmHg or less for 1 hour to obtain a water-dispersible polyester resin (A) of Production Example A1 shown in Table 1. .
Thereafter, A2, A3, A4, A5, A6 and C1, C2 water-dispersible polyester resins (A) shown in Table 1 were produced in the same manner.

  25 parts of the obtained water-dispersible polyester resin (A) was charged into a mixed solution of 15 parts of isopropanol and 60 parts of ion-exchanged water, stirred at 70 to 80 ° C. for 3 hours, and the solid content concentration shown in Table 1 was 25%. An aqueous dispersion of water-dispersible polyester resin (A) was obtained.

Production of glycidyl group-containing acrylic resin (B) In a beaker, 18 parts of ion exchange water and 3 parts of Eleminol RS-3000 (Sanyo Kasei Kogyo Co., Ltd., anionic surfactant, active ingredient 50%) as a surfactant are charged. While stirring, 40 parts of glycidyl methacrylate is added to prepare a monomer emulsion. Next, in a four-necked flask equipped with a condenser, a monomer dropping funnel, a thermometer, and a stirrer, 37.5 parts of ion exchange water, 1 part of Eleminol RS-3000 as a surfactant, 0.5 part of potassium persulfate Then, after stirring and stirring with nitrogen, heating is started and the monomer emulsion is added dropwise at 75 ° C. over 4 hours. The reaction is allowed to proceed while maintaining the liquid temperature at 75 to 85 ° C. even after completion of the dropwise addition, and then cooled after 4 hours. After cooling, ion exchange water was further added to obtain a glycidyl group-containing acrylic resin (B) of Production Example B1 described in Table 2 having a nonvolatile content of 25%.
Thereafter, B2, B3, B4, and B5 glycidyl group-containing acrylic resins (B) and D1, D2, and D3 glycidyl groups that do not contain the glycidyl groups shown in Table 2 were obtained in the same manner.

Production of water-dispersible resin composition Tables 3 and 4 show the water-dispersible polyester resin (A) obtained above, the glycidyl group-containing acrylic resin (B), and the acrylic resin (B) not containing glycidyl groups. The water dispersible resin compositions of Examples 1 to 11 and Comparative Examples 1 to 11 were obtained by blending at the indicated ratio%.

Example of coating and performance evaluation of water-dispersible resin composition obtained above Example of coating on polyester film Water-dispersible so that the coating thickness after drying on a biaxially stretched polyester film with a film thickness of 100 μm is 3 μm The resin composition was applied and dried at 110 ° C. for 3 minutes, and then heat treated at 150 ° C. for 1 minute. The following test was done about the obtained processed film. The results are shown in Table 3 and Table 4.

(1) Evaluation of transparency of coating The cloudiness of the processed surface was visually determined.
○: Transparent, △: Cloudy, ×: Opaque

(2) Adhesion evaluation to polyester film According to the cross-cut tape method, cellophane tape (CT405A-18 manufactured by Nichiban Co., Ltd.) was bonded onto the processed surface so that air did not enter, and peeled off in the 180 ° direction. The remaining degree of the later processed layer was determined according to the following criteria.
○: Residual rate 100%, Δ: Residual rate 99-80%, X: Residual rate 79% or less

(3) Water resistance evaluation After the processed film was immersed in warm water at 90 ° C for 1 hour, it was determined by change in appearance.
○: No change in appearance, △: Whitening of film, ×: Dissolution

(4) Evaluation of solvent resistance The surface was rubbed 50 times with absorbent cotton impregnated with toluene, methyl ethyl ketone, ethyl acetate, and isopropanol, and then judged by changes in appearance.
○: No change in appearance, △: Whitening of film, ×: Dissolution

The results are as shown in Table 3 and Table 4, and in Examples 1 to 11, the transparency of the film and the adhesion to the PET film were good and the performances excellent in water resistance and solvent resistance were obtained. On the other hand, Comparative Examples 1 to 11 did not satisfy all the performances.

Claims (4)

  An ester-forming sulfonic acid alkali metal salt compound is copolymerized as a dicarboxylic acid component, and a water-dispersible polyester resin (A) in which diethylene glycol is copolymerized as a diglycol component and a glycidyl group-containing radical polymerizable unsaturated monomer are copolymerized. The acrylic resin (B) as a main component, and the resin solid content weight ratio of (A) and (B) is (A) / (B) = 10-80 / 90-20. A water-dispersible resin composition that forms a film having water resistance and solvent resistance.   The dicarboxylic acid component that is a copolymerization component of the water-dispersible polyester resin (A) is composed of an aromatic dicarboxylic acid and an ester-forming alkali metal salt compound, and the ester-forming alkali metal salt compound is contained in all the acid components. It contains 6-20 mol%, The water-dispersible resin composition of Claim 1 characterized by the above-mentioned.   The water dispersibility according to claim 1 or 2, wherein diethylene glycol is contained in the total glycol component as a diglycol component which is a copolymer component of the water dispersible polyester resin (A). Resin composition. 4. The water according to claim 1, wherein the copolymerizable monomer of the acrylic resin (B) contains a glycidyl group-containing radical polymerizable unsaturated monomer in an amount of 10 to 100% by weight in all monomers. Dispersible resin composition.