JP2005281558A - Aqueous resin composition for paper fiber binder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a nonwoven fabric excellent in molding resistance, which is suitable for fiber processing and paper processing, and is prevented from being broken at the time of molding under a low temperature condition particularly when used as an aqueous resin composition for a nonwoven fabric binder. An aqueous resin composition for paper fiber binders is provided.
An aqueous resin composition for paper fiber binders obtained by emulsion polymerization of an ethylenically unsaturated monomer containing 98% by weight or more of (meth) acrylate as a main component in an aqueous medium. 100% modulus in the tensile test at a measurement temperature of 110 ° C. of the coating formed by the method is 0.2 MPa or more, and the elongation at break in the tensile test at a measurement temperature of 110 ° C. of the coating is 700% or more, and The glass transition temperature of the coating is in the range of 0 to 70 ° C.
[Selection] Figure 1

Description

  The present invention relates to an aqueous resin composition for paper fiber binder. More specifically, the present invention relates to an aqueous resin composition for paper fiber binders that is suitable for fiber processing and paper processing, and has excellent molding resistance in which fracture during molding is prevented, and particularly relates to an aqueous resin composition suitable for nonwoven fabric binders. .

Conventionally, an aqueous resin composition substantially using an acrylic resin alone can be designed in a wide range from very hard to soft by changing the composition ratio of the monomers, and various functionalities can be obtained. Since various physical properties can be imparted by copolymerizing a monomer having a group, it is used as an acrylic emulsion-type binder, for example, as an adhesive or a pressure-sensitive adhesive. It has been widely used in the processing field.
However, for example, non-woven fabric processed with an acrylic emulsion type binder is generally subjected to secondary processing such as dyeing and molding in the post-process, but if the binder used during processing is a soft type, This results in a problem that it is difficult to hold the mold of the nonwoven fabric due to its weak binding force. Conversely, when the binder is a hard type, there is a problem that the processed product such as the nonwoven fabric breaks during molding. .

In order to improve these problems, a method has been proposed in which a plasticizer for plasticizing a hard polymer (hereinafter referred to as “film-forming aid”) is added to soften the film.
However, the method of softening the coating by adding a film-forming aid has a problem that the hardness of the coating changes in a short period because the plasticizer contained disappears from the coating over time. .

Also, a method of improving the strength at the time of heating by copolymerizing a monomer mainly composed of (meth) acrylamide in the presence of seed emulsion as a core particle to form a multilayer structure particle (Patent Document 1). Has been proposed.
However, this method of forming multilayer structure particles by copolymerization of monomers discloses a multistage polymerization latex intended for applications requiring heat resistance, but the problem of breakage during molding is still insufficient. It was not solved and was not practical.
Especially for base materials that cannot be exposed to high temperatures, such as non-woven fabrics made of polypropylene or the like, the molding process is performed at a normal molding temperature, for example, at a temperature of about 150 ° C., due to fiber fusion or breakage. In general, the molding is performed at a relatively low temperature of about 100 ° C. However, when molding is performed under low temperature conditions, breakage during molding is more likely to occur, which is never a practical solution.

  For these reasons, there has been a strong demand for the development of an aqueous resin composition for paper fiber binders that does not cause breakage during molding under low-temperature conditions and has excellent molding resistance, particularly suitable for nonwoven fabric binders. .

Japanese Unexamined Patent Publication No. 7-26461 (claims on page 2 to page 3, right column, paragraph 0021)

  The object of the present invention is an aqueous resin composition for paper fiber binders, which is suitable for fiber processing and paper processing, and particularly when used as an aqueous resin composition for nonwoven fabric binders, fracture at the time of molding under low temperature conditions It is an object to provide an aqueous resin composition for paper fiber binders that can form a nonwoven fabric excellent in molding resistance in which the above is prevented.

  As a result of intensive studies to solve the above problems, the present inventors have been able to solve the above problems by using an aqueous resin composition for paper fiber binders in which the resulting coating has a specific range of characteristic values. The headline and the present invention were completed.

  That is, the present invention is a measurement temperature of a film formed by an aqueous resin composition obtained by emulsion polymerization of an ethylenically unsaturated monomer containing 98% by weight or more of (meth) acrylate as a main component in an aqueous medium. The 100% modulus in a tensile test at 110 ° C. is 0.2 MPa or more, the elongation at break in a tensile test at a measurement temperature of 110 ° C. is 700% or more, and the glass transition temperature of the coating is 0 to 0. The present invention provides an aqueous resin composition for paper fiber binder characterized by being in the range of 70 ° C.

  The aqueous resin composition for paper fiber binder of the present invention has a 100% modulus in a tensile test at a measurement temperature of 110 ° C. of a coating film formed using the paper fiber binder of 0.2 MPa or more, and an elongation at break of 700% or more. In addition, the glass transition temperature of the coating is in the range of 0 to 70 ° C., and since it has excellent film forming properties and cohesive force at the time of thermoforming, molding has been a problem in the past. It is possible to prevent troubles due to breakage of time and to greatly improve productivity.

The matters necessary for carrying out the present invention are described below.
The aqueous resin composition for paper fiber binder of the present invention is an aqueous resin composition obtained by emulsion polymerization of an ethylenically unsaturated monomer having (meth) acrylate as a main component in an aqueous medium.
The “main component” in the present invention means a case where 98% by weight or more is contained in all components.

The aqueous resin composition for paper fiber binder has a 100% modulus in a tensile test at a measurement temperature of 110 ° C. of the film formed from the aqueous resin composition for paper fiber binder of 0.2 MPa or more, and The breaking elongation in a tensile test at a measurement temperature of 110 ° C. is preferably 700% or more, and more preferably 1000% or more under the same conditions.
In the film formed from the aqueous resin composition for paper fiber binder, if the condition that 100% modulus and elongation at break are satisfied, the cohesive force can be effectively maintained as a binder at the time of thermoforming and can follow deformation. Therefore, it is possible to greatly improve the breaking of the fiber during molding.

Furthermore, the film formed from the aqueous resin composition for paper fiber binder of the present invention has a glass transition temperature (hereinafter also referred to as “actually measured Tg”) measured under the conditions described later in the range of 0 to 70 ° C. It is preferable that the measured Tg is in the range of 10 to 50 ° C.
If the measured Tg of the film formed from the aqueous resin composition for paper fiber binder is within such a range, the film forming property and the cohesive force at the time of thermoforming are excellent. As a result, productivity can be greatly improved.

Furthermore, the aqueous resin composition for paper fiber binder of the present invention has a flow start temperature of 150 ° C. or lower under the condition that the cylinder pressure of the Koka type flow tester using the same is 1.96 × 10 ⁶ Pa. It is preferable that it is in the range of 50 to 130 ° C.
If the flow start temperature of the film formed from the aqueous resin composition for paper fiber binder is within such a range, troubles due to tearing during molding under low temperature conditions can be prevented, and productivity can be greatly improved. Can do.

  Subsequently, each raw material used for manufacture of the aqueous resin composition for paper fiber binders of this invention is described in detail below.

  In the production of the aqueous resin composition for paper fiber binder of the present invention, an ethylenically unsaturated monomer mainly composed of (meth) acrylate is used as described above, but other ethylenically unsaturated monomers are used. Examples of the body include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, hexyl ( (Meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, etc. (Meth) acrylic acid Steals; vinyl compounds having an aromatic ring such as phenyl (meth) acrylate, benzyl (meth) acrylate, styrene, α-methylstyrene, vinyltoluene, vinylanisole, α-halostyrene, vinylnaphthalene, divinylstyrene; acrylic acid, Methacrylic acid, β-carboxyethyl (meth) acrylate, 2- (meth) acryloylpropionic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, itaconic acid half ester, maleic acid half ester, β- (meth) acryloyloxy Ethyl hydrogen succinate, β- (meth) hydroxyethyl hydrogen phthalate and salts thereof, acid anhydrides such as maleic anhydride, itaconic anhydride; 2,2,2-trifluoroethyl (meth) acrylate, 2,2, 3,3- Fluorine-containing ethylene such as n-fluoropropyl (meth) acrylate, perfluorocyclohexyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, β- (perfluorooctyl) ethyl (meth) acrylate Unsaturated monomers; glycidyl group-containing polymerizable monomers such as glycidyl (meth) acrylate and allyl glycidyl ether; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, polyethylene glycol mono (meta) ) Hydroxyl group-containing polymerizable monomers such as acrylate and glycerol mono (meth) acrylate; aminoethyl (meth) acrylate, N-monoalkylaminoalkyl (meth) acrylate, N, N-dialkylaminoalkyl (meth) acrylate Amino group-containing polymerizable monomers such as 2-aziridinyl ethyl (meth) acrylate; aziridinyl group-containing polymerizable monomers such as allyl (meth) acrylate; Cyclopentenyl group-containing polymerizable monomers such as dicyclopentenyl (meth) acrylate; ethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylol Examples include propane tri (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, diallyl phthalate, divinylbenzene, allyl (meth) acrylate, and the like. These may be used alone or in combination of two or more.

  Furthermore, examples of the polymerizable monomer that can be used together with the ethylenically unsaturated monomer include N-methylol (meth) acrylamide, N-isopropoxymethyl (meth) acrylamide, and N-butoxymethyl (meth) acrylamide. , N-isobutoxymethyl (meth) acrylamide and other methylolamide groups or alkoxylated monomers-containing polymerizable monomers; vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ -(Meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropylmethyldiethoxysilane, γ- (Meta) acrylo Propyltriisopropoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane and salts thereof, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxy Silyl group-containing polymerizable monomers such as propyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane; (meth) acryloyl isocyanate, (meth) acryloyl isocyanate ethyl Isocyanate groups and / or blocked isocyanate group-containing polymerizable monomers such as phenol or methyl ethyl ketoxime adducts; Oxazoline group-containing polymerizable compounds such as 2-isopropenyl-2-oxazoline and 2-vinyl-2-oxazoline Monomer; (Meth) Ac Amide group-containing polymerizable monomers such as luamide, N-monoalkyl (meth) acrylamide, N, N-dialkyl (meth) acrylamide; Carbonyl group-containing polymerizable monomers such as acrolein and diacetone (meth) acrylamide; Acetoxy group-containing polymerizable monomer such as acetoxyethyl (meth) acrylate, sulfonic acid group and / or sulfate group (and / or salt thereof), phosphoric acid group and / or phosphate ester group (and / or salt thereof) ) -Containing ethylenically unsaturated monomers, vinyl sulfonic acids such as vinyl sulfonic acid and styrene sulfonic acid or salts thereof, allyl group-containing sulfonic acids such as allyl sulfonic acid and 2-methylallyl sulfonic acid, or salts thereof ( (Meth) acrylic acid 2-sulfoethyl, (meth) acrylic acid 2-sulfopropyl, etc. “Adekalysoap PP-70, PPE-710” having acryloyl group-containing sulfonic acids or salts thereof, (meth) acrylamide group-containing sulfonic acids such as (meth) acrylamide-t-butylsulfonic acid or salts thereof, and phosphate groups [Asahi Denka Kogyo Co., Ltd.]; Vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl versatate; Vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, amyl vinyl ether, hexyl vinyl ether Nitrile group-containing ethylenically unsaturated monomers such as (meth) acrylonitrile; radical polymerization of isoprene, chloroprene, butadiene, ethylene, tetrafluoroethylene, vinylidene fluoride, N-vinylpyrrolidone, etc. Possible monomers and the like. These may be used alone or in combination of two or more.

The aqueous resin composition for a paper fiber binder of the present invention is usually obtained by using the ethylenically unsaturated monomer in the presence of a polymerization initiator and, if necessary, additives such as an emulsifier and a dispersion stabilizer. Further, if necessary, it can be obtained by copolymerizing a mixture of other polymerizable monomers copolymerizable with these monomers in an aqueous medium.
The polymerization method at that time is not particularly limited. For example, (1) a method in which monomers, other polymerizable monomers, water, a polymerization initiator, etc. are mixed together for polymerization, or (2) a simple method. Examples include a so-called pre-emulsion method in which a monomer, other polymerizable monomer, water, an emulsifier and the like previously mixed are dropped, or (3) a monomer dropping method.

The aqueous resin composition for paper fiber binder can be obtained by emulsion polymerization of the various monomers in an aqueous medium in the presence of additives such as an emulsifier and a free radical generating catalyst.
As the emulsifier, various anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants and the like can be used.
Examples of the anionic surfactant include sulfates of higher alcohols, alkylbenzene sulfonates, polyoxyethylene alkylphenyl sulfonates, polyoxyethylene polycyclic phenyl ether sulfates [for example, manufactured by Nippon Emulsifier Co., Ltd. Newcol 707SF] and the like may be used, and these may be used alone, or two or more may be used in combination as long as the reaction is not inhibited.
Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene-polyoxypropylene block copolymer, and the like. These may be used alone or in combination of two or more. May be used in a range that does not inhibit the reaction.
Examples of the cationic surfactant include alkylammonium chloride [for example, Lion Card Co., Ltd. ARCARD 16-50]. These may be used alone or in combination of two or more in a range that does not inhibit the reaction. May be.
Examples of the amphoteric surfactant include polyoxyethylene alkyl sulfate, polyoxyethylene alkylphenyl sulfate, and the like. These may be used alone or in combination of two or more in a range not inhibiting the reaction. Good.
Furthermore, if necessary, an emulsifier having a polymerizable unsaturated group in the molecule, generally called “reactive emulsifier”, can be used. Examples of such a reactive emulsifier include commercially available products such as “Latemul S-180” (manufactured by Kao Corporation) having a sulfonic acid group and a salt thereof, “Eleminol JS-2, RS-30” [Sanyo Chemical Industries, Ltd. Etc.] having a sulfate group and a salt thereof, “AQUALON HS-10, HS-1025, KH-05, KH-10”, [Daiichi Kogyo Seiyaku Co., Ltd.], “Adekaria soap SE-10, "SE-20" [Asahi Denka Kogyo Co., Ltd.] etc .; "New Frontier A-229E" having a phosphate group [Daiichi Kogyo Seiyaku Co., Ltd.] etc .; "Aqualon RN-" having a nonionic hydrophilic group 10, RN-20, RN-30, RN-50 "[Daiichi Kogyo Seiyaku Co., Ltd.] etc., and these may be used alone or in combination of two or more.

  Examples of other dispersion stabilizers other than the emulsifier that can be used in the production of the aqueous resin composition for paper fiber binder include, for example, polyvinyl alcohol, fiber ether, starch, maleated polybutadiene, maleated alkyd resin, and polyacrylic. Water-soluble polymer substances such as acids (salts), polyacrylamides, water-based acrylic resins, water-based polyester resins, water-based polyamide resins, water-based polyurethane resins, and the like can be mentioned. It may be used, or two or more may be used in combination.

The aqueous medium used when producing the aqueous resin composition for paper fiber binder is not particularly limited, and water may be used alone or a mixed solvent of water and a water-soluble solvent may be used.
The above-mentioned “mixed solvent of water and water-soluble solvent” usable in the present invention is a mixed solvent of a water-soluble solvent mainly composed of water, and the water-soluble solvent with respect to the total amount of the mixed solvent. The content of is preferably 10% by weight or less, more preferably 5% by weight or less.

  Examples of the water-soluble solvent include alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, ethyl carbitol, ethyl cellosolve, butyl cellosolve, or polar solvents such as N-methylpyrrolidone, which may be used alone. Two or more kinds may be used in combination.

  Moreover, as a polymerization initiator used when producing the aqueous resin composition for paper fiber binder, a radical polymerization initiator is usually used. Examples of the radical polymerization initiator include potassium persulfate, sodium persulfate, Persulfates such as ammonium persulfate, diacyl peroxides such as benzoyl peroxide, lauroyl peroxide, decanoyl peroxide, dialkyl peroxides such as t-butyl cumyl peroxide, dicumyl peroxide, t-butyl peroxide Peroxyesters such as laurate and t-butylperoxybenzoate, organic peroxides such as cumene hydroperoxide, paramentane hydroperoxide, hydroperoxide such as t-butyl hydroperoxide, hydrogen peroxide Etc. That.

  Further, a redox polymerization initiator in which the peroxide and a reducing agent are used in combination can be used. Examples of the reducing agent include ascorbic acid and its salt, erythorbic acid and its salt, tartaric acid and its salt, citric acid and And salts thereof, metal salts of formaldehyde sulfoxylate, sodium thiosulfate, sodium bisulfite, ferric chloride and the like, and 4,4′-azobis (4-cyanovaleric acid), 2,2′-azobis ( It is also possible to use an azo initiator such as 2-amidinopropane) dihydrochloride, and one or a mixture of two or more of these polymerization initiators can be used.

In the aqueous resin composition for paper fiber binder, when it is necessary to adjust the molecular weight of the polymer to be used, a compound having chain transfer ability may be added as a molecular weight modifier.
Examples of such molecular weight regulators include mercaptans such as lauryl mercaptan, octyl mercaptan, dodecyl mercaptan, 2-mercaptoethanol, octyl thioglycolate, 3-mercaptopropionic acid, thioglycerin, or α-methylstyrene dimer. Is mentioned.

Moreover, in order to neutralize the carboxyl group in the aqueous resin composition for paper fiber binder, a neutralizing agent can be used.
As the neutralizing agent, any basic substance can be used as long as it does not impair the object of the present invention. Examples thereof include alkali metal compounds such as sodium hydroxide and potassium hydroxide; calcium hydroxide and calcium carbonate. Alkaline earth metal compounds such as ammonia; water-soluble such as ammonia; monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monopropylamine, dimethylpropylamine, monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, diethylenetriamine Organic amines etc. are mentioned, These may be used individually and may use 2 or more types together. Among these, in order to further improve the water resistance of the obtained film, it is preferable to use ammonia that is easily scattered by normal temperature or heating.

  The polymerization temperature at the time of producing the aqueous resin composition for paper fiber binder varies depending on various conditions depending on the type of monomer to be used, the type of polymerization initiator, and the like. In the case of emulsion polymerization, it is usually preferably carried out in the range of 30 to 90 ° C. If emulsion polymerization is carried out in this temperature range, uniform and stable polymer particles can be obtained with almost no unreacted monomer remaining.

The water-based resin composition for paper fiber binder can also be used by mixing a water-soluble or water-dispersible thermosetting resin within a range not impairing the object of the present invention.
The water-soluble or water-dispersible thermosetting resin is not particularly limited, and examples thereof include phenol resin, urea resin, melamine resin, polyester resin, polyamide resin, and polyethylene resin, and these may be used alone. Two or more kinds may be used in combination.

  Further, the aqueous resin composition for paper fiber binder of the present invention contains known and commonly used additives such as pigments, pH adjusters, film forming aids, leveling agents, thickeners, water repellents, and antifoaming agents. It can be added appropriately as long as the object of the invention is not impaired.

  The aqueous resin composition for paper fiber binder of the present invention is, for example, synthetic fiber such as polyester fiber, polyamide fiber, polyimide fiber, acrylic fiber, regenerated fiber such as regenerated cellulose fiber, semi-synthetic fiber such as acetate fiber, or silk. It can be used for, for example, yarns, nonwoven fabrics, woven fabrics, knitted fabrics, or papers composed of at least one material selected from the group consisting of natural fibers such as cotton, wool, and pulp.

The 100% modulus in the tensile test at a measurement temperature of 110 ° C. of the coating formed from the aqueous resin composition for paper fiber binder of the present invention is preferably 0.2 MPa or more, and the measurement temperature of the coating at 110 ° C. The elongation at break in the tensile test is preferably 700% or more. Excellent protection for the coated fiber provided that 100% modulus and elongation at break in the tensile test at a measurement temperature of 110 ° C. of the coating formed from the aqueous resin composition for paper fiber binder satisfy the above conditions. And flexibility can be imparted.
The 100% modulus and elongation at break in the tensile test described above were obtained by using a test piece obtained in Examples described later in accordance with a predetermined test method and using a tensile tester at a temperature of 110 ° C. It is a value based on a numerical value obtained by measuring the elongation in the axial direction when pulled in the axial direction under the condition of 200 mm / min.

  Furthermore, if the glass transition temperature (measured Tg) of the film formed by the aqueous resin composition for paper fiber binder of the present invention is in the range of 0 to 70 ° C., fiber shrinkage suppression in the dyeing process and after the molding process It is possible to exert an excellent effect on mold retainability and the like.

The flow viscosity at 70 ° C. at a cylinder pressure of 1.96 × 10 ⁷ Pa of the high-pressure flow tester for coating using the aqueous resin composition for paper fiber binder of the present invention is 10 ⁶ to 10 ⁸ Pa · s. For example, excellent molding resistance can be obtained in a fiber processed product, a nonwoven fabric processed product, a paper processed product and the like using the aqueous resin composition for paper fiber binder of the present invention.
Furthermore, if the flow start temperature under the condition that the cylinder pressure of the coating formed by the aqueous resin composition for paper fiber binder of the present invention is 1.96 × 10 ⁶ Pa is 150 ° C. or less, the paper fiber binder of the present invention is used. Excellent low-temperature moldability can be obtained at the time of molding fiber processed products, nonwoven fabric processed products, paper processed products and the like using the aqueous resin composition.

  The aqueous resin composition for paper fiber binder of the present invention provides a paper fiber binder having excellent molding resistance, particularly a nonwoven fabric binder, and is useful in fields where molding resistance is required. It exhibits excellent effects as a binder for interior fabrics such as interior materials, ceiling materials, paper fiber embossed products, dust filters, etc., and can be used in a wide range.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention more concretely, the scope of the present invention is not limited only to these Examples.
In the following, unless otherwise specified, “%” represents “% by weight”, and “part” represents “part by weight”.
The measurement method and evaluation method used in the present invention are as follows.

[Measurement method of 100% modulus in tensile test at measurement temperature of 110 ° C.]
A water-based resin composition was poured into a glass plate having a frame on all sides so that the film thickness after drying was 0.5 mm, and dried at 40 ° C. for 8 hours in a thermostatic PHH-200 manufactured by Tabai Co. Was peeled off from the glass plate and further dried at 140 ° C. for 5 minutes, and punched into a strip of 1 cm width × 10 cm length to prepare a sample. Using this sample, a tensile test was conducted at a crosshead speed of 200 mm / min in an atmosphere of 110 ° C. with a Tensilon RTM-100 type tensile tester manufactured by Orientec Co., Ltd., and 100% strain was applied. The stress was measured and set to 100% modulus (MPa).

[Measurement method of elongation at break in tensile test at 110 ° C.]
A water-based resin composition was poured into a glass plate having a frame on all sides so that the film thickness after drying was 0.5 mm, and dried at 40 ° C. for 8 hours in a thermostatic PHH-200 manufactured by Tabai Co. Was peeled off from the glass plate and further dried at 140 ° C. for 5 minutes, and punched into a strip of 1 cm width × 10 cm length to prepare a sample. Using this sample, the elongation at break (%) when a tensile test was carried out at a crosshead speed of 200 mm / min in an atmosphere of 110 ° C. with a Tensilon RTM-100 type tensile tester manufactured by Orientec Co., Ltd. It was measured.

[Measurement method of fluid viscosity of coating]
After coating the aqueous resin composition on a glass plate so that the film thickness after drying is 0.7 mm and drying at 40 ° C. for 8 hours, the resulting coating is peeled off from the glass plate and further at 140 ° C. for 5 minutes. The dried product was used with a Koka-type flow tester CFT-500D manufactured by Shimadzu Corporation. Die length 1.0 mm, die hole diameter 1.0 mm, cylinder pressure 1.96 × 10 ⁷ Pa, preheating time 600 Second, the viscosity when flowing out under the condition of a temperature rising rate of 3.0 ° C./min was measured, and the viscosity at 70 ° C. (Pa · s) was measured.

[Measurement method of coating flow start temperature]
After coating the aqueous resin composition on a glass plate so that the film thickness after drying is 0.7 mm and drying at 40 ° C. for 8 hours, the resulting coating is peeled off from the glass plate and further at 140 ° C. for 5 minutes. The dried product was used with a Koka-type flow tester CFT-500D manufactured by Shimadzu Corporation. Die length 1.0 mm, die hole diameter 1.0 mm, cylinder pressure 1.96 × 10 ⁶ Pa, preheating time 600 The temperature (° C.) when flowing out under conditions of a second and a heating rate of 3.0 ° C./min was measured.

[Measurement Method of Glass Transition Temperature (Measured Tg)]
After coating the aqueous resin composition on a glass plate so that the film thickness after drying is 0.7 mm and drying at 40 ° C. for 8 hours, the resulting coating is peeled off from the glass plate and further at 140 ° C. for 5 minutes. Using the dried sample as a sample, about 10 mg of a sample was weighed into an aluminum cylindrical cell having a diameter of 5 mm and a depth of 2 mm, and a DSC-2920 modulated differential scanning calorimeter manufactured by TA Instruments was used. The endothermic curve when the temperature was increased from 50 ° C. to 150 ° C. at a temperature increase rate of 20 ° C./min was measured and determined.
For reference, an example of how to obtain the glass transition temperature (measured Tg) at the time of measuring an endothermic curve with a differential scanning calorimeter is shown in FIG. The glass transition temperature (actually measured Tg) in the present invention is a value represented as “T ₂ ” in FIG. 1, a straight line equidistant from the extended straight line of each baseline in the vertical axis direction, and the glass transition. It is the temperature at the point where the curve of the step-like change part intersects.

[Method for preparing sample for evaluation of molding resistance]
A polyester spunbond with a basis weight of 100 g / m ² is impregnated with a 1DIP / 1NIP aqueous resin composition diluted to a solid content of 20%, dried in a dryer at 100 ° C. for 3 minutes, and further 150 ° C. A heat treatment was performed under the condition of × 2 minutes to obtain a sample for evaluation of molding resistance.

[Measurement method of molding resistance]
The sample for evaluation of molding resistance prepared to 50 mm × 80 mm was attached to a jig, and left at a predetermined atmospheric temperature for 3 minutes using an autograph AG-5000C manufactured by Shimadzu Corporation, and then a head speed of 300 mm. The sample was deformed to a depth of 25 mm with another jig at / min. The sample was taken out with care so as not to damage the sample excessively, and the sample was visually inspected for damage.
The number of tests was 10 and the evaluation results were determined according to the following criteria.
○: Breaking occurred only when the number of tests was less than 20% of the total number of tests.
Δ: Breaking occurred when the number of tests was 20% or more and less than 60% with respect to the total number of tests.
X: Breakage occurred when the number of tests was 60% or more with respect to the total number of tests.

[Example 1]
In a polymerization vessel equipped with a stirrer, 374 parts of ion exchange water was charged, and the temperature in the reaction vessel was raised to 80 ° C. while stirring while feeding nitrogen gas. After raising the temperature, 4 parts of the monomer emulsion (1) having the following composition was added to the reaction vessel, and then 0.6 parts of ammonium persulfate was added to initiate polymerization. After maintaining the temperature in the reaction vessel at 80 ° C. for 10 minutes, 522 parts of the remaining monomer emulsion (1) and the following polymerization initiator aqueous solution (2) were simultaneously added dropwise to the reaction vessel for polymerization. It was. The dropping time was 4 hours for the monomer emulsion (1) and 4.5 hours for the polymerization initiator aqueous solution (2), and the polymerization was completed while maintaining the temperature in the reaction vessel at 80 ° C. After completion of the polymerization, the pH was adjusted with aqueous ammonia to obtain an acrylate copolymer emulsion having a solid content of 45% and a pH of 5.5.
Composition of monomer emulsion (1) Butyl acrylate; 120 parts Methyl methacrylate; 315 parts Methacrylic acid; 15 parts New Coal 707SN [manufactured by Nippon Emulsifier Co., Ltd.]; 40 parts Ion-exchanged water; 100 parts Polymerization initiator aqueous solution ( 2) Composition: ammonium persulfate; 1 part ion exchange water; 75 parts Table 1 shows the evaluation results of the coating obtained using the aqueous resin composition for paper fiber binder of the present invention obtained in Example 1. The flow viscosity at 70 ° C. at a cylinder pressure of 1.96 × 10 ⁷ Pa is 1 × 10 ⁷ Pa · s, the elongation at break in a tensile test at a measurement temperature of 110 ° C. is 850%, and the 100% modulus is It was 0.38 MPa. Moreover, the molding resistance of the sample obtained from this aqueous resin composition was good at both 150 ° C and 100 ° C.

[Example 2]
An aqueous resin composition for paper fiber binder of the present invention was obtained in the same manner as in Example 1 except that the monomer mixture shown in Table 1 was used. Moreover, the flow viscosity in 70 degreeC in the cylinder pressure of 1.96 * 10 < ⁷ > Pa in the film obtained using this aqueous resin composition is 8 * 10 < ⁶ > Pa * s, and the tensile test in the measurement temperature of 110 degreeC The elongation at break was 1600% and the 100% modulus was 0.30 MPa. Moreover, the molding resistance of the sample obtained from this aqueous resin composition was good at both 150 ° C and 100 ° C.

[Comparative Examples 1-4]
An aqueous resin composition was obtained in exactly the same manner as in Example 1 except that the monomer mixture shown in Table 2 was used. Table 2 shows the flow viscosity at 70 ° C., the 100% modulus and elongation at break in the tensile test at a measurement temperature of 110 ° C., and the mold resistance of the sample obtained from this aqueous resin composition. It was.

  Since the aqueous resin composition for paper fiber binder of the present invention is excellent in film forming property and cohesive force during thermoforming, for example, in a wide range of fields such as film coating, adhesive, fiber processing resin, paper processing resin, etc. Troubles caused by tearing during molding can be prevented, and productivity can be greatly improved. In particular, when used as a nonwoven fabric binder, it is possible to provide a nonwoven fabric that is excellent in moldability under low temperature conditions.

It is explanatory drawing which showed an example of how to obtain | require the glass transition temperature (measured Tg) at the time of the endothermic curve measurement by a differential scanning calorimeter. The glass transition temperature (actually measured Tg) is a value represented as “T ₂ ” in FIG. 1, and each baseline of the extrapolated glass transition start temperature (T ₁ ) and the extrapolated glass transition end temperature (T ₃ ). Is a temperature T ₂ at which the straight line equidistant (H / 2) in the vertical axis direction from the extended straight line intersects with the curve of the stepped change portion of the glass transition.

Explanation of symbols

T ₁ : extrapolated glass transition start temperature (° C.)
T ₂ : Glass transition temperature (midpoint glass transition temperature) (° C.)
T ₃ : Extrapolation glass transition end temperature (° C.)
H: Heat flow (mW)

Claims (3)

A water-based resin composition obtained by emulsion polymerization of an ethylenically unsaturated monomer containing (meth) acrylate as a main component and containing 98% by weight or more in an aqueous medium, and a film formed by the aqueous resin composition The 100% modulus in the tensile test at a measurement temperature of 110 ° C. is 0.2 MPa or more, the elongation at break in the tensile test at a measurement temperature of 110 ° C. is 700% or more, and the glass transition temperature of the coating Is in the range of 0 to 70 ° C, an aqueous resin composition for paper fiber binders. 2. The flow start temperature is 150 ° C. or less under the measurement conditions in which the cylinder pressure of the high flow type flow tester using the aqueous resin composition for paper fiber binder is 1.96 × 10 ⁶ Pa. An aqueous resin composition for paper fiber binders. In the film formed from the aqueous resin composition for paper fiber binder, the flow viscosity at 70 ° C. when the cylinder pressure by the Koka type flow tester is 1.96 × 10 ⁷ Pa is in the range of 10 ⁶ to 10 ⁸ Pa · s. The aqueous resin composition for paper fiber binders according to claim 1 or 2.

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