JP2007247111A - Binder emulsion for nonwoven fabric and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a binder for a nonwoven fabric, which is of non-formalin type, is free from endocrine disrupter, is preferably useful as an environmental correspondence article, has excellent water resistance and solvent resistance and comprises an aqueous emulsion. <P>SOLUTION: The binder emulsion for a nonwoven fabric comprises a copolymer (B) that is obtained by polymerizing a radically polymerizable unsaturated monomer (A) composed of a vinyl cyanide-based monomer (a1), a carboxy group-containing vinyl-based monomer (a2) and a crosslinkable functional group-containing vinyl-based monomer (a3) except the monomers (a1) and (a2) in an aqueous medium and has a glass transition temperature of -10 to 40°C. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thermosetting binder used when producing a nonwoven fabric used for a textile product. More specifically, the present invention relates to a binder for nonwoven fabric made of an aqueous emulsion that does not generate formalin and is excellent in water resistance and solvent resistance.

  Aqueous acrylic emulsions are used in various coating agents such as aqueous paints, aqueous pressure-sensitive adhesives / adhesives, fiber processing agents such as binders for nonwoven fabrics, binders for paper processing, and water-based inks.

  Traditionally, raw cotton is impregnated with a binder and dried to produce non-woven fabrics that are used in various textile products. Many of the binders used have environmental problems such as safety and health, and many of them cause environmental problems such as generation of formalin. Non-formaline-type binders that do not have these problems, non-environmental hormone-free binders such as nonylphenol substances, and nonwoven fabric products using such binders are desired.

  Non-formalin type binders for non-woven fabrics have been tried by various methods. However, in terms of final physical properties, especially in terms of washability (dry cleaning properties), they tend to be inferior to conventional formalin-containing binders.

  In addition, as for the non-formalin type, a resin combined type, for example, a combined type of epoxy resin and acrylic resin, a crosslinking agent added type, and the like have been studied, but there are many problems in workability and cost.

For example, Patent Document 1 discloses a method for producing a heat-resistant nonwoven fabric using a binder composition that does not contain formaldehyde.
However, the composition of Patent Document 1 focuses on heat resistance, and unlike the present invention, the binder (binder) is a polyacid-curing system and does not use an acrylic vinyl monomer. . Moreover, since it presupposes use under high temperature (for example, 125 degreeC or more), it is inadequate at the point that the texture (hardness) of the obtained nonwoven fabric cannot be controlled.

  Patent Document 2 discloses a formaldehyde-free crosslinkable emulsion polymer obtained by adding N- (2,2-dialkoxy-1-hydroxy) ethylacrylamide polymerized to a vinyl ester base. And there is description that this emulsion is used as a nonwoven fabric binder. However, there is no description regarding the washing resistance of the resulting cured product, particularly the resistance to halogen-containing solvents such as parkren used in dry cleaning, and the practicality as a binder for nonwoven fabric is considered to be insufficient.

Further, Patent Document 3 discloses an emulsion for a nonwoven fabric binder in which formaldehyde release is suppressed. In order to reduce the amount of formaldehyde derived from N-methylolacrylamide which is a crosslinkable monomer, a redox catalyst is disclosed. It is characterized by adding a reducing component of the system, particularly a glycolic acid adduct of sodium sulfite.
However, the invention disclosed in Patent Document 3 essentially contains N-methylolacrylamide, which is a formaldehyde generation source, and the possibility of releasing formaldehyde into the atmosphere is not wiped out.

Furthermore, Patent Document 4 discloses an acrylic emulsion having a high level of chemical stability, which is obtained by polymerizing a radical polymerizable acrylic monomer having an acrylamide monomer as an essential component. However, Patent Document 4 does not describe washing resistance, particularly solvent resistance, and is insufficient in terms of practicality as a binder for nonwoven fabric.
Japanese Patent Laid-Open No. 5-179551 Japanese Patent Laid-Open No. 5-178940 JP-A-2002-212372 Japanese Patent Laid-Open No. 2004-292749

  An object of the present invention is to provide a non-formalin type and environmental hormone-free non-woven fabric binder that is preferably used as an environmentally-friendly product and is excellent in water resistance and solvent resistance, and is made of an aqueous emulsion.

As a result of intensive studies, the present inventors have reached the present invention.
That is, the first invention relates to a vinyl monomer (a3) having a crosslinkable functional group other than the vinyl cyanide monomer (a1), the carboxyl group-containing vinyl monomer (a2) and (a1), (a2). The present invention relates to a binder emulsion for nonwoven fabrics, characterized in that it contains a copolymer (B) having a glass transition temperature of -10 to 40 ° C, which is obtained by polymerizing a radically polymerizable unsaturated monomer (A) containing the polymer in an aqueous medium. .

  Moreover, 2nd invention is related with the binder emulsion for nonwoven fabrics of the 1st invention characterized by the functional group of the vinyl-type monomer (a3) which has a crosslinkable functional group being an epoxy group.

  Further, the third invention relates to the binder emulsion for nonwoven fabric according to the first invention, wherein the functional group of the vinyl monomer (a3) having a crosslinkable functional group is a hydroxyl group.

  Furthermore, the fourth invention is any one of the first to third inventions, further comprising a vinyl monomer having an alkoxysilyl group as the vinyl monomer (a3) having a crosslinkable functional group. It relates to the binder emulsion for nonwoven fabrics described.

  According to the present invention, it is possible to provide a non-formalin type and environmental hormone-free non-woven fabric binder made of an aqueous emulsion that is preferably used as an environmentally friendly product and is excellent in water resistance and solvent resistance.

  The binder emulsion for nonwoven fabric of the present invention is a vinyl monomer (a3) having a crosslinkable functional group other than the vinyl cyanide monomer (a1), the carboxyl group-containing vinyl monomer (a2) and (a1), (a2). Containing a copolymer (B) obtained by polymerizing a radically polymerizable unsaturated monomer (A) containing

In the present invention, the polymerization of the radical polymerizable unsaturated monomer (A) is preferably carried out by emulsion polymerization. Among these, it is preferable to use a so-called multistage polymerization method in which the radically polymerizable unsaturated monomer (A) is emulsion-polymerized in an aqueous medium in two or more steps. For example, in the case of two-stage polymerization, a first monomer emulsion containing a part of the radically polymerizable unsaturated monomer (A) charged in the reaction vessel, an emulsifier and water is polymerized, and the first polymer emulsion (P1 And then, in the presence of the first polymer emulsion (P1), the remainder of the radically polymerizable unsaturated monomer (A), a second monomer emulsion containing an emulsifier and water are added and polymerized. Is preferred. If it is a multistage polymerization of three or more stages, the same operation is further repeated.
That is, even if the composition and amount of the monomer to be used and the type and amount of the emulsifier are the same, the radical polymerizable unsaturated monomer (A) is not charged in the reaction vessel, but the emulsifier, the polymerization initiator, and water. Or a polymerization initiator and water, an emulsifier and water, or only water, and a radical polymerizable unsaturated monomer (A), an emulsifier, a polymerization initiator and water. A monomer emulsion containing a radical polymerizable unsaturated monomer (A), an emulsifier and water, a mixture of a radical polymerizable unsaturated monomer (A) and an emulsifier, a radical polymerizable unsaturated monomer ( When only A) is dropped and polymerized, the particle size distribution of the resulting emulsion is larger than when the radically polymerizable unsaturated monomer (A) is previously charged in the reaction vessel. And it becomes much low molecular weight component, the resultant cured product tends to washing resistance (water resistance, solvent resistance) decreases.
In the present invention, the polymerization initiator may be previously charged in the reaction vessel together with the radical polymerizable unsaturated monomer (A) or the like, or may be contained in the monomer emulsion in the second and subsequent stages to be dropped. Alternatively, it may be added dropwise to the reaction vessel separately from the radically polymerizable unsaturated monomer (A) and the emulsifier.

It is important that the glass transition temperature (hereinafter also referred to as “Tg”) of the copolymer (B) contained in the nonwoven fabric binder emulsion of the present invention is in the range of −10 to 40 ° C.
When Tg is less than −10 ° C., the cured product tends to be sticky and blocking tends to occur.
On the other hand, when Tg exceeds 40 ° C., the film formability is inferior and the physical properties are liable to be lowered.
The Tg of the copolymer (B) is a conventionally known theoretical formula based on the type and composition ratio of the radical polymerizable unsaturated monomer (A) to be used for polymerization and the glass transition temperature of those homopolymers. Can be calculated.

Examples of the vinyl cyanide monomer (a1) used in the present invention include acrylonitrile and methacrylonitrile, and acrylonitrile is preferred from the viewpoint of versatility.
Although the detailed mechanism is unknown, the water resistance and solvent resistance of the cured product obtained from the binder emulsion for nonwoven fabric of the present invention due to the presence of the vinyl cyanide monomer (a1) which is an organic cyano compound containing a cyano group. It is effective in improving sex.
The amount of vinyl cyanide monomer (a1) used is preferably 5 to 20% by weight, more preferably 8 to 12% by weight, out of a total of 100% by weight of the radical polymerizable unsaturated monomer (A). preferable.
If the vinyl cyanide monomer is less than 5% by weight, the effect of improving the solvent resistance tends to be insufficient. On the other hand, if it exceeds 20% by weight, the water-soluble radically polymerizable unsaturated monomer (A) becomes too water-soluble and polymerization stability is increased. Is inferior, the generation of aggregates increases, the copolymerizability with other monomers decreases, and the conversion rate tends to decrease, which is not preferable.

The carboxyl group-containing monomer (a2) used in the present invention provides stability to the resulting nonwoven fabric binder emulsion and reacts with the functional group in the vinyl monomer (a3) having a crosslinkable functional group described later. It is used for the purpose of imparting good water resistance and solvent resistance to the cured product obtained from the binder emulsion for nonwoven fabric of the present invention by forming a crosslinked structure.
As the carboxyl group-containing vinyl monomer (a2),
Carboxyl groups or carboxylic acid anhydrides such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid half ester, maleic acid half ester, maleic anhydride, itaconic anhydride, 2-methacryloylpropionic acid Examples of the group-containing vinyl monomer include acrylic acid and methacrylic acid.
As a usage-amount of a carboxyl group-containing vinyl-type monomer (a2), it is preferable that it is 1 to 7 weight% in the total 100 weight% of a radically polymerizable unsaturated monomer (A), and it is 1 to 4 weight%. More preferred.
When the carboxyl group-containing vinyl monomer (a2) is less than 1% by weight, the polymerization stability tends to decrease, and the mechanical stability and storage stability of the resulting emulsion tend to decrease.
On the other hand, if it exceeds 7% by weight, it is not preferable because, when adjusting the pH of the emulsion, it tends to cause a high viscosity and also tends to cause a decrease in water resistance of the resulting cured product.

The vinyl monomer (a3) having a crosslinkable functional group other than (a1) and (a2) used in the present invention is such that the crosslinkable functional group is a carboxyl group or a carboxylic acid in the carboxyl group-containing monomer (a2). Used for the purpose of imparting good water resistance and solvent resistance to the cured product obtained from the binder emulsion for nonwoven fabric of the present invention by reacting with an anhydride group and / or by self-crosslinking.
Although it does not specifically limit as a kind of the crosslinkable functional group of the vinyl type monomer (a3) which has a crosslinkable functional group, An epoxy group or a hydroxyl group is preferable, Furthermore, the vinyl type which has at least any one of these functional groups It is more preferable to use a monomer in combination with a vinyl monomer having an alkoxysilyl group.

Examples of the vinyl monomer having an epoxy group include glycidyl (meth) acrylate.
Examples of the vinyl monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate.
Examples of the vinyl monomer having an alkoxysilyl group include 3-methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, and vinyltrimethoxysilane.

The amount of the vinyl monomer (a3) having a crosslinkable functional group other than (a1) and (a2) is a vinyl type having an epoxy group in a total of 100% by weight of the radical polymerizable unsaturated monomer (A). The monomer is preferably 2 to 10% by weight, and more preferably 3 to 5% by weight.
If the amount used is less than 2% by weight, the crosslinkability tends to be low, whereas if it exceeds 10% by weight, an uncrosslinked product tends to remain, such being undesirable.
Moreover, it is preferable that it is 2-10 weight% as a vinyl-type monomer which has a hydroxyl group, and it is more preferable that it is 3-5 weight%.
If the amount used is less than 2% by weight, the crosslinkability tends to be low. On the other hand, if it exceeds 10% by weight, a water-soluble uncrosslinked product tends to remain, which tends to cause a decrease in water resistance.
Moreover, as a vinyl-type monomer which has an alkoxy silyl group, it is preferable that it is 0.01 to 10 weight%, and it is more preferable that it is 0.1 to 5 weight%.
If the amount used is less than 0.01% by weight, the crosslinkability tends to be low. On the other hand, if it exceeds 10% by weight, an uncrosslinked product tends to remain and the polymerization stability is poor.

As the radically polymerizable unsaturated monomer (A) used in the present invention, other monomers than the above (a1) to (a3) can be used in order to obtain desired physical properties.
Such monomers include
Acrylic esters such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate,
Methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate;
Maleic acid, fumaric acid, itaconic acid esters;
Vinyl esters such as vinyl acetate, vinyl propionate and tertiary tertiary carboxylate;
Aromatic vinyl compounds such as styrene and vinyltoluene;
Heterocyclic vinyl compounds such as vinylpyrrolidone;
Vinyl chloride, vinyl ether, vinyl ketone, vinyl amide;
Vinylidene halide compounds such as vinylidene chloride and vinylidene fluoride;
Α-olefins such as ethylene and propylene;
Examples thereof include dienes such as butadiene.
Furthermore, polyethylenically unsaturated monomers such as divinylbenzene ethylene dimethacrylate can also be used.

Any emulsifier can be used as long as it is conventionally used in emulsion polymerization for obtaining the nonwoven fabric binder emulsion of the present invention. Typical examples include anionic emulsifiers such as alkylbenzene sulfonates, alkyl sulfates, polyoxyethylene alkylphenyl sulfonates, polyoxyethylene alkyl ether sulfate esters, dialkyl sulfosuccinate salts, and polyoxyethylene alkyls. Nonionic emulsifiers such as ether, polyoxyethylene alkylphenyl ether, polyoxyethylene-polyoxypropylene block copolymer, and the like can be mentioned. Of course, the present invention is not limited to these, and any emulsifier that can be used at the time of emulsion polymerization is not limited to the above-mentioned skeleton, and any of them can be used, and a plurality of these can be used in combination. .
As these emulsifiers, it is preferable to use those which do not correspond to endocrine disrupting substances (environmental hormone substances).
A reactive emulsifier is preferred from the viewpoint of the water resistance of a cured product formed from the binder emulsion for nonwoven fabrics.

  Specific examples of reactive emulsifiers include sodium vinyl sulfonate, polyoxyethylene ammonium sulfate acrylate, polyoxyethylene sulfonate sodium methacrylate, polyoxyethylene alkenyl phenyl sulfonate ammonium, polyoxyethylene alkenyl phenyl sulfate, sodium allylalkyl Examples include anionic reactive emulsifiers such as sulfosuccinate and polyoxypropylene sulfonate sodium methacrylate, and nonionic reactive emulsifiers such as polyoxyethylene alkenyl phenyl ether and polyoxyethylene methacryloyl ether.

For example, as a commercial product thereof, Aqualon HS-10, KH-10, New Frontier A-229E [above, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.], Adeka Soap SE-3N, SE-5N, SE-10N SE-20N, SE-30N [manufactured by Asahi Denka Kogyo Co., Ltd.], Antox MS-60, MS-2N, RA-1120, RA-2614, [manufactured by Nippon Emulsifier Co., Ltd.], Eleminol JS- 2, anionic reactive emulsifiers such as RS-30 [above, Sanyo Chemical Industries, Ltd.], Latemul S-120A, S-180A, S-180 [above, Kao Corporation],
Aqualon RN-20, RN-30, RN-50, New Frontier N-177E [above, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.], Adeka Soap NE-10, NE-20, NE-30, NE-40 [ Asahi Denka Kogyo Co., Ltd.], RMA-564, RMA-568, RMA-1114, [Nippon Emulsifier Co., Ltd.], NK Ester M-20G, M-40G, M-90G, M- Nonionic reactive emulsifiers such as 230G [above, Shin-Nakamura Chemical Co., Ltd.]
Examples of the non-reactive emulsifier include 1118S-70, Emal 10 [manufactured by Kao Corporation] RA-9612 [manufactured by Nippon Emulsifier Co., Ltd.], and the like. It is also possible to use a plurality of these in combination.
The reactive emulsifier is not included in the radical polymerizable unsaturated monomer (A) referred to in the present invention.

  Examples of the radical polymerization initiator that can be used in the present invention include persulfates such as potassium persulfate, ammonium persulfate, and sodium persulfate, azobisisobutyronitrile and its hydrochloride, 2,2′-azobis ( 2-aminodipropane) dihydrochloride, azo initiators such as 4,4'-azobis (4-cyanovaleric acid), peroxide initiators such as hydrogen peroxide and tertiary butyl hydroperoxide, etc. Is mentioned. Examples of the reducing agent that can be used in combination with these radical initiators include sodium bisulfite, sodium pyrosulfite, and L-ascorbic acid. A redox initiator using a radical initiator and a reducing agent in combination is preferable, but a thermal decomposition system using only a radical initiator may be used.

  Raw cotton (cotton, synthetic fiber, glass fiber, etc.) processed to a certain thickness is impregnated through a liquid diluted with the binder emulsion for nonwoven fabric of the present invention to remove excess liquid, and then dried and cured. By such a method, a nonwoven fabric having good washing resistance (water resistance, solvent resistance) can be obtained.

  EXAMPLES Hereinafter, although an Example and a comparative example are hung up and this invention is demonstrated in detail, this invention is not limited only to a following example. The following parts and% are values based on weight.

[Example 1] (implemented on a scale 10 times the amount in Table 1)
A reaction vessel equipped with a thermometer, a dropping funnel and a reflux condenser and replaced with nitrogen gas was charged with 540 parts of an initial charge of ion-exchanged water.
Further, as a monomer, methyl methacrylate (hereinafter abbreviated as “MMA”): 100 parts, butyl acrylate (hereinafter abbreviated as “BA”): 67 parts, acrylonitrile (hereinafter abbreviated as “AN”): 20 parts, itacon Acid (hereinafter abbreviated as “IA”): 7.5 parts, 2 hydroxyethyl methacrylate (hereinafter abbreviated as “2HEMA”): 5 parts, Emar-10 which is an anionic emulsifier (available from Kao Corporation) 25 parts of an aqueous solution in which 5 parts were dissolved and 22 parts of an aqueous solution in which 5 parts of RA-9612 (produced by Nippon Emulsifier Co., Ltd.) were dissolved were mixed and stirred to obtain a pre-emulsion.
On the other hand, the dripping portion is charged into the dropping funnel. Ion exchange water: 200 parts,
As monomers, MMA: 409 parts, BA: 272 parts, AN: 80 parts, IA: 22.5
Part, 2HEMA: 15 parts, 3-methacryloxypropyltrimethoxysilane (hereinafter abbreviated as “3-MAPS”): 2 parts, Emar-10 which is an anionic emulsifier, 2.5 parts active ingredient (manufactured by Kao Corporation) An aqueous solution in which 25 parts of an aqueous solution in which RA-9612 (manufactured by Nippon Emulsifier Co., Ltd.) was dissolved in 22 parts of an active ingredient was charged in a dropping funnel, mixed, stirred and emulsified to obtain a pre-emulsion.
After raising the internal temperature of the reaction vessel to 50 ° C, 15 parts of 5% aqueous solution of ammonium persulfate: 15 parts and 15 parts of 2.5% aqueous solution of sodium bisulfite were added to the reaction vessel as a polymerization initiator to initiate the reaction. .
Five minutes after the start of the reaction, 35 parts of the pre-emulsion and 5% aqueous solution of ammonium persulfate and 65 parts of 2.5% aqueous solution of sodium bisulfite were started to be added dropwise from separate dropping funnels.
While maintaining the internal temperature at 65 ° C., it was continuously added dropwise over 3 hours, and after completion of the addition, reaction was further performed at that temperature for 2 hours.
It was confirmed that the reaction rate was 99% or more with a dry residue dried for 20 minutes with a 150 ° C. hot air dryer, and after cooling, the pH was adjusted with 25% aqueous ammonia (25 parts). The mixture was filtered through a 150 mesh filter cloth to obtain a copolymer emulsion having a nonvolatile content of 50% and a viscosity (BH viscometer / No3 rotor 20 rpm): 2400 mPa · s. The glass transition temperature (theoretical value) of the copolymer obtained from the monomer subjected to copolymerization was 35 ° C.

Example 2 to Example 5
The compositions shown in Table 1 were polymerized in the same manner as in Example 1 to obtain respective aqueous acrylic copolymer emulsions.

[Example 2]: (Same as Example 1, carried out on a 10-fold scale of Table 1)
A reaction was carried out in the same manner as in Example 1 except that the monomer composition for the reaction vessel charge and the dropping funnel charge was changed as follows to obtain a copolymer emulsion.
(Reaction vessel)
MMA: 90 parts BA: 67 parts AN: 20 parts IA: 7.5 parts GMA: 10 parts (GMA: glycidyl methacrylate)
(Drip funnel)
MMA: 389 parts BA: 272 parts AN: 80 parts IA: 22.5 parts GMA: 40 parts 3-MAPS: 2 parts The resulting copolymer emulsion has a non-volatile content: 50%, viscosity (BH viscometer No3 Rotor 20 rpm): 1230 mPa · s. Moreover, the glass transition temperature (theoretical value) of the copolymer calculated | required from the monomer with which it used for copolymerization was 35 degreeC.

[Example 3]: (Same as Example 1, carried out on a 10-fold scale of Table 1)
A reaction was carried out in the same manner as in Example 1 except that the monomer composition for the reaction vessel charge and the dropping funnel charge was changed as follows to obtain a copolymer emulsion.
(Reaction vessel)
MMA: 43 parts BA: 123 parts AN: 20 parts IA: 7.5 parts 2HEMA: 5 parts (dropping funnel)
MMA: 176 parts BA: 506 parts AN: 80 parts IA: 22.5 parts 2HEMA: 15 parts 3-MAPS: 2 parts The resulting copolymer emulsion has a non-volatile content: 50%, viscosity (BH viscometer No3 Rotor 20 rpm): 1500 mPa · s. Moreover, the glass transition temperature (theoretical value) of the copolymer calculated | required from the monomer with which it used for copolymerization was -6.5 degreeC.

[Example 4]: (Same as Example 1, carried out on a 10-fold scale of Table 1)
A reaction was carried out in the same manner as in Example 1 except that the monomer composition for the reaction vessel charge and the dropping funnel charge was changed as follows to obtain a copolymer emulsion.
(Reaction vessel)
MMA: 42 parts BA: 123 parts AN: 20 parts IA: 7.5 parts GMA: 5 parts (dropping funnel)
MMA: 167 parts BA: 506 parts AN: 80 parts IA: 22.5 parts GMA: 25 parts 3-MAPS: 2 parts The resulting copolymer emulsion has a non-volatile content: 50%, viscosity (BH viscometer No3 Rotor 20 rpm): 1290 mPa · s. Moreover, the glass transition temperature (theoretical value) of the copolymer calculated | required from the monomer with which it used for copolymerization was -6.5 degreeC.

[Example 5]: (Same as Example 1, carried out on a 10-fold scale of Table 1)
A reaction was carried out in the same manner as in Example 1 except that the monomer composition for the reaction vessel charge and the dropping funnel charge was changed as follows to obtain a copolymer emulsion.
(Reaction vessel)
MMA: 90 parts BA: 67 parts AN: 20 parts IA: 7.5 parts GMA: 10 parts (drip funnel)
MMA: 391 parts BA: 272 parts AN: 80 parts IA: 22.5 parts GMA: 40 parts The resulting copolymer emulsion has a non-volatile content: 50%, viscosity (BH viscometer / No3 rotor 20 rpm): 1200 mPa · s. Moreover, the glass transition temperature (theoretical value) of the copolymer calculated | required from the monomer with which it used for copolymerization was 35 degreeC.

Comparative Example 1 to Comparative Example 2
The compositions shown in Table 1 were polymerized in the same manner as in Example 1 to obtain respective aqueous acrylic copolymer emulsions.
[Comparative Example 1] (implemented on a scale 10 times the amount of Table 1)
A reaction was carried out in the same manner as in Example 1 except that the monomer composition for the reaction vessel charge and the dropping funnel charge was changed as follows to obtain a copolymer emulsion.
(Reaction vessel)
MMA: 120 parts BA: 34 parts IA: 7.5 parts 2HEMA: 5 parts (dropping funnel)
MMA: 488 parts BA: 306 parts IA: 22.5 parts 2HEMA: 15 parts 3-MAPS: 2 parts The resulting copolymer emulsion has a non-volatile content: 50%, viscosity (BH viscometer / No3 rotor 20 rpm): It was 1200 mPa · s. Moreover, the glass transition temperature (theoretical value) of the copolymer calculated | required from the monomer with which it used for copolymerization was 35 degreeC.

[Comparative Example 2]: (Similar to Comparative Example 1, the measurement was carried out on a 10-fold scale shown in Table 1.)
A reaction was carried out in the same manner as in Example 1 except that the monomer composition for the reaction vessel charge and the dropping funnel charge was changed as follows to obtain a copolymer emulsion.
(Reaction vessel)
MMA: 65 parts BA: 123 parts IA: 7.5 parts 2HEMA: 5 parts (dropping funnel)
MMA: 253 parts BA: 507 parts IA: 22.5 parts 2HEMA: 15 parts 3-MAPS: 2 parts The resulting copolymer emulsion has a non-volatile content of 50%, viscosity (BH viscometer / No3 rotor 20 rpm): It was 1500 mPa · s. Moreover, the glass transition temperature (theoretical value) of the copolymer calculated | required from the monomer with which it used for copolymerization was -6.5 degreeC.

[Comparative Example 3]: (Similar to Comparative Example 1, the measurement was carried out on a 10-fold scale shown in Table 1.)
A reaction vessel equipped with a thermometer, a dropping funnel, and a reflux condenser and charged with nitrogen gas was charged with 540 parts of an initial charge of ion-exchanged water.
Furthermore, as monomers, methyl methacrylate (MMA): 65 parts, butyl acrylate (BA): 124 parts, itaconic acid (IA): 7.5 parts, 2 hydroxyethyl methacrylate (2HEMA): 5 parts, N-methylol Acrylamide (MAM): 5 parts, 25 parts of an aqueous solution in which 2.5 parts of active ingredient Emar-10 (manufactured by Kao Corporation) is dissolved, NC-200 (manufactured by Lion Corporation) is effective as a nonionic emulsifier 25 parts of an aqueous solution in which 6.25 parts of the component were dissolved was mixed and stirred to emulsify to obtain a pre-emulsion.
On the other hand, the dripping portion is charged into the dropping funnel.
Ion exchange water: 200 parts, MMA as monomer: 233 parts, BA: 506 parts, IA: 22.5 parts, 2HEMA: 15 parts, 3-methacryloxypropyltrimethoxysilane (3-MAPS): 2 parts, MAM: 15. 15 parts of an anionic emulsifier, Emar-10, 25 parts of an aqueous solution dissolving 2.5 parts of an active ingredient (manufactured by Kao Corporation), NC-200 (manufactured by Lion Corporation) an active ingredient of a nonionic emulsifier 75 parts of an aqueous solution in which 75 parts were dissolved was mixed and stirred to emulsify to obtain a pre-emulsion.
After raising the internal temperature of the reaction vessel to 50 ° C., 15 parts of 5% aqueous solution of ammonium persulfate: 15 parts and 15 parts of 2.5% aqueous solution of sodium bisulfite were added to the reaction vessel as a polymerization initiator to initiate the reaction. .
Five minutes after the start of the reaction, 35 parts of the pre-emulsion and 5% aqueous solution of ammonium persulfate and 70 parts of 2.5% aqueous solution of sodium bisulfite were started to be added dropwise from separate dropping funnels.
While maintaining the internal temperature at 65 ° C., it was continuously added dropwise over 3 hours, and after completion of the addition, reaction was further performed at that temperature for 2 hours.
It was confirmed that the reaction rate was 99% or more with a residue dried for 20 minutes with a 150 ° C. hot air dryer, and after cooling, the pH was adjusted with 25% aqueous ammonia (25 parts). The mixture was filtered through a 150 mesh filter cloth to obtain a copolymer emulsion having a nonvolatile content of 50% and a viscosity (BH viscometer / No3 rotor 20 rpm): 1100 mPa · s. The glass transition temperature (theoretical value) of the copolymer obtained from the monomer subjected to the copolymerization was −6.5 ° C.

(Evaluation method and evaluation criteria)
(1) Polymerization stability:
After the completion of the reaction, the amount of the resin adhered to the reaction vessel and the total amount of the aggregate after filtration with a 150 mesh filter cloth were weighed and evaluated by the weight ratio in the total amount of the produced emulsion.
The evaluation criteria are as follows.
○: Good (less than 0.05%)
Δ: Slightly problematic (0.05% or more and less than 0.1%)
X: Defect (0.1% or more)

(2) Water resistance (substitute test for water washability)
The emulsion was applied to a glass plate with a 5 mil applicator. After drying at room temperature for 1 hour and further drying at 130 ° C. for 5 minutes, it is immersed in warm water at 25 ° C. and judged from the degree of whitening and the state of the film.
○: No whitening after 30 minutes of immersion.
Δ: Whitening within 30 minutes of immersion.
×: Whitening and swelling within 30 minutes of immersion.
Note that whitening means that the 8-point character cannot be corrected.
(3) Solvent resistance (Dry cleaning substitute test):
The emulsion was applied to a glass plate with a 5 mil applicator. After drying at room temperature for 1 hour and further drying at 130 ° C. for 5 minutes, the surface state after wiping the surface of the coating film 10 times with a cloth impregnated with a parklene solvent was observed and judged.
○: No abnormal surface condition.
Δ: Surface state slightly dissolved and peeled ×: Whole surface dissolved and peeled

Claims (4)

Radical polymerizable unsaturated monomer containing vinyl monomer (a3) having a crosslinkable functional group other than vinyl cyanide monomer (a1), carboxyl group-containing vinyl monomer (a2) and (a1), (a2) ( A binder emulsion for nonwoven fabric, comprising a copolymer (B) obtained by polymerizing A) in an aqueous medium and having a glass transition temperature of -10 to 40 ° C. The binder emulsion for nonwoven fabrics according to claim 1, wherein the functional group of the vinyl monomer (a3) having a crosslinkable functional group is an epoxy group. The binder emulsion for nonwoven fabric according to claim 1, wherein the functional group of the vinyl monomer (a3) having a crosslinkable functional group is a hydroxyl group. The binder emulsion for nonwoven fabrics according to any one of claims 1 to 3, further comprising a vinyl monomer having an alkoxysilyl group as the vinyl monomer (a3) having a crosslinkable functional group.