JP2019173220A - (meth) acrylic resin emulsion for paper coating, and film and laminate - Google Patents

Abstract

The present invention provides a (meth) acrylic resin emulsion, a film, and a laminate for paper coating, which can form a film having excellent water resistance and blocking resistance even when dried at a low temperature. A structural unit (A) derived from a (meth) acrylic monomer having a carboxy group and a structural unit (B) derived from a reactive surfactant having an ethylenically unsaturated double bond, The content of the structural unit (A) is 0.1% by mass or more and 10% by mass or less based on the total mass of the structural units (excluding the structural unit (B)), and ) Is 0.5% by mass or more and 10% by mass or less based on the total mass of the structural units (however, excluding the structural unit (B)), and the glass transition temperature is 0 ° C or more and 40 ° C or less. And a (meth) acrylic resin emulsion for paper coating containing resin particles having an average particle diameter of 30 nm or more and 200 nm or less, and an aqueous medium, and applications thereof. [Selection diagram] None

Description

  The present disclosure relates to a (meth) acrylic resin emulsion for paper coating, a film, and a laminate.

In printing using paper as a base material, it is known to perform surface treatment on the base material in order to provide various functions such as thermal coloring and prevention of bleeding after printing. Such a surface treatment facilitates uniform and smooth coating on the surface of the substrate, and is excellent in terms of environment and safety. Therefore, an aqueous composition containing a resin emulsion (hereinafter referred to as “functional composition”). ") Is used.
In the surface treatment using paper as a base material, unlike the surface treatment using a metal or resin film as a base material, the functional composition penetrates into the base material, and the active ingredient remains on the surface of the base material. There is a problem that it is difficult. For this reason, coating (so-called water-resistant coating) for imparting water resistance is performed on the surface of the paper substrate before coating with the functional composition. Also, resin emulsions, particularly (meth) acrylic resin emulsions, are widely used in coating liquids (hereinafter referred to as “water-resistant coating liquids”) used for such water-resistant coatings.

For example, Patent Document 1 discloses a back layer solution containing an acrylic emulsion having a glass transition point of 10 ° C. or lower.
Patent Document 2 discloses a coating liquid containing an acrylic resin emulsion containing a cationic surfactant and a nonionic surfactant.
Patent Document 3 discloses a coating liquid containing a styrene / acrylic resin having a glass transition point of 10 ° C. or lower.

JP 2004-284089 A JP 2005-329599 A JP 2009-255309 A

  In general, a paper substrate coated with water resistance is wound after the drying process. Therefore, the water-resistant coating liquid is required to be able to form a film that is excellent not only in water resistance but also in blocking resistance.

By the way, in recent years, in order to reduce the damage to the paper base material, it is required to lower the temperature of the drying process (generally, about 80 ° C.) as compared with the conventional art.
However, when the conventional water-resistant coating liquid is dried at a low temperature (for example, 60 ° C. or less), it has been difficult to realize formation of a film excellent in both water resistance and blocking resistance.

The problem to be solved by the present invention is to provide a (meth) acrylic resin emulsion for paper coating that can form a film excellent in water resistance and blocking resistance even when dried at a low temperature.
The problem to be solved by the present invention is to provide a film excellent in water resistance and blocking resistance.
Furthermore, the problem to be solved by the present invention is to provide a laminate having a film excellent in water resistance and blocking resistance.

Specific means for solving the above problems include the following modes.
<1> A structural unit (A) derived from a (meth) acrylic monomer having a carboxy group and a structural unit (B) derived from a reactive surfactant having an ethylenically unsaturated double bond, and The content of the structural unit (A) is 0.1% by mass to 10% by mass with respect to the total mass of the structural unit (excluding the structural unit (B)), and the structural unit (B) Is 0.5 mass% or more and 10 mass% or less with respect to the total mass of the structural unit (excluding the structural unit (B)), and the glass transition temperature is 0 ° C. or higher and 40 ° C. or lower. A (meth) acrylic resin emulsion for paper coating, which contains resin particles having an average particle diameter of 30 nm to 200 nm and an aqueous medium.
<2> The structural unit (C) derived from a monomer having a glass transition temperature of −80 ° C. or more and −50 ° C. or less when the resin is a homopolymer, and the glass transition temperature when the resin is a homopolymer. (Meth) acrylic resin emulsion for paper coating as described in <1> which has a structural unit (D) derived from the monomer of 30 to 120 degreeC.
<3> The (meth) acrylic resin emulsion for paper coating according to <1> or <2>, wherein the reactive surfactant is an anionic reactive surfactant.
<4> The (meth) acrylic resin emulsion for paper coating according to any one of <1> to <3>, wherein the reactive surfactant has an oxyalkylene group having an average addition mole number of 5 to 40.
<5> A structural unit (A) derived from a (meth) acrylic monomer having a carboxy group and a structural unit (B) derived from a reactive surfactant having an ethylenically unsaturated double bond, and The content of the structural unit (A) is 0.1% by mass to 10% by mass with respect to the total mass of the structural unit (excluding the structural unit (B)), and the structural unit (B) Is 0.5 mass% or more and 10 mass% or less with respect to the total mass of the structural unit (excluding the structural unit (B)), and the glass transition temperature is 0 ° C. or higher and 40 ° C. or lower. And a film containing a melt of resin particles having an average particle diameter of 30 nm to 200 nm.
<6> A laminate having the film according to <5> on a paper substrate.

According to the present invention, a (meth) acrylic resin emulsion for paper coating that can form a film excellent in water resistance and blocking resistance even when dried at a low temperature is provided.
Moreover, according to this invention, the film | membrane excellent in water resistance and blocking resistance is provided.
Furthermore, according to this invention, the laminated body which has a film | membrane excellent in water resistance and blocking resistance is provided.

It is the schematic explaining the evaluation test method of blocking resistance in the Example of this invention, (A) is a side surface schematic diagram, (B) is an upper surface schematic diagram.

  Hereinafter, specific embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present invention.

In the present specification, a numerical range indicated using “to” means a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively.
In the numerical ranges described stepwise in the present specification, the upper limit value or lower limit value described in a numerical range may be replaced with the upper limit value or lower limit value of the numerical range described in another stepwise manner. . Further, in the numerical ranges described in this specification, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the values shown in the examples.
In the present specification, a combination of two or more preferred embodiments is a more preferred embodiment.
In the present specification, the amount of each component means the total amount of the plurality of types of substances unless there is a specific notice when there are a plurality of types of substances corresponding to each component.

  In the present specification, “(meth) acryl” is a term including both acrylic and methacrylic, “(meth) acrylate” is a term including both acrylate and methacrylate, and “(meth) acryloyl group” "Is a term that encompasses both acryloyl and methacryloyl groups.

In the present specification, the term “(meth) acrylic resin” means that the content of a structural unit derived from a monomer having a (meth) acryloyl group is a structural unit of a resin (however, having an ethylenically unsaturated double bond). It means a resin that is 50% by mass or more based on the total mass of the structural unit derived from the reactive surfactant.
The “monomer” in the present specification does not include a reactive surfactant.

  In this specification, the term “process” is not limited to an independent process, and is included in this term if the intended purpose of the process is achieved even when it cannot be clearly distinguished from other processes. It is.

[(Meth) acrylic resin emulsion for paper coating]
The (meth) acrylic resin emulsion for paper coating of the present invention (hereinafter also simply referred to as “(meth) acrylic resin emulsion”) is a structural unit derived from a (meth) acrylic monomer having a carboxy group (A) and It has a structural unit (B) derived from a reactive surfactant having an ethylenically unsaturated double bond (hereinafter also referred to simply as “reactive surfactant”), and the content of the structural unit (A) is The structural unit (however, excluding the structural unit (B)) is 0.1% by mass or more and 10% by mass or less with respect to the total mass of the structural unit. 0.5 mass% to 10 mass% with respect to the total mass of the unit (B)), the glass transition temperature is 0 ° C to 40 ° C, and the average particle size is 30 nm to 200 nm. Resin particles and water Including, and the media.
According to the (meth) acrylic resin emulsion of the present invention, a film excellent in water resistance and blocking resistance can be formed even when dried at a low temperature.

  The (meth) acrylic resin emulsion of the present invention is used for coating paper. The (meth) acrylic resin emulsion of the present invention has a structural unit (A) derived from a (meth) acrylic monomer having a carboxy group and a structural unit (B) derived from a reactive surfactant. The content of (A) is 0.1% by mass or more and 10% by mass or less with respect to the total mass of the structural unit (excluding the structural unit (B)), and the content of the structural unit (B) is , 0.5 mass% to 10 mass% with respect to the total mass of the structural units (excluding the structural unit (B)), the glass transition temperature is 0 ° C. or higher and 40 ° C. or lower, and the average Resin particles having a particle size of 30 nm or more and 200 nm or less exist in a state of being dispersed in an aqueous medium.

  Hereinafter, each component of the (meth) acrylic resin emulsion of the present invention will be described.

[Resin particles]
The resin particles contained in the (meth) acrylic resin emulsion of the present invention are composed of a structural unit (A) derived from a (meth) acrylic monomer having a carboxy group and a structural unit (B) derived from a reactive surfactant. The content of the structural unit (A) is 0.1% by mass or more and 10% by mass or less based on the total mass of the structural unit (excluding the structural unit (B)), and the structural unit ( The content of B) is 0.5% by mass to 10% by mass with respect to the total mass of the structural units (excluding the structural unit (B)), and the glass transition temperature is 0 ° C. or higher and 40 ° C. or lower. And the average particle size is 30 nm or more and 200 nm or less.
First, the structural units of the resin constituting the resin particles will be described.

<Structural unit (A)>
The resin has a structural unit (A) derived from a (meth) acrylic monomer having a carboxy group, and the proportion (that is, content) of the structural unit (A) is a structural unit of the resin (provided that It is 0.1 mass% or more and 10 mass% or less with respect to the total mass of a structural unit (B).
In the present specification, the “structural unit derived from a (meth) acrylic monomer having a carboxy group” means a structural unit formed by addition polymerization of a (meth) acrylic monomer having a carboxy group.

There is no restriction | limiting in particular as a kind of (meth) acryl monomer which has a carboxy group.
Specific examples of the (meth) acrylic monomer having a carboxy group include (meth) acrylic acid, crotonic acid, maleic anhydride, fumaric acid, itaconic acid, glutaconic acid, citraconic acid, and 2- (meth) acryloyloxyethyl. And succinic acid, ω-carboxy-polycaprolactone mono (meth) acrylate, and the like.
Among these, as the (meth) acrylic monomer having a carboxy group, for example, at least one selected from acrylic acid (AA) and methacrylic acid (MAA) is preferable.
Since acrylic acid (AA) and methacrylic acid (MAA) have one carboxy group, the crosslink density is easily controlled and the copolymerization with other (meth) acrylic monomers is good. Is preferable.

  The resin may have only one type of structural unit (A) or may have two or more types.

The proportion (that is, content) of the structural unit (A) in the resin is 0.1% by mass to 10% by mass with respect to the total mass of the structural units of the resin (excluding the structural unit (B)). 0.5 mass% or more and 5 mass% or less is preferable, and 0.5 mass% or more and 3 mass% or less is more preferable.
The content of the structural unit (A) in the resin is 0.1% by mass or more based on the total mass of the structural units of the resin (excluding the structural unit (B)). A) is positively shown. When the resin has the structural unit (A), the carboxy group is ionized in the aqueous medium, and the surface of the resin particles is negatively charged, so electrostatic repulsion occurs between the resin particles. Therefore, it shows a tendency that aggregation of resin particles in the aqueous medium is suppressed. When the aggregation of the resin particles is suppressed, uniform coating can be performed on the paper, so that the water resistance of the formed film can be improved.
When the content of the structural unit (A) in the resin is 10% by mass or less with respect to the total mass of the structural units of the resin (excluding the structural unit (B)), many carboxy groups exhibiting hydrophilicity are present. Therefore, even when dried at a low temperature, the surface of the formed film exhibits hydrophobicity. Therefore, formation of a film having excellent water resistance can be realized.

<Constitutional unit derived from a monomer other than a (meth) acrylic monomer having a carboxy group>
Resin is a monomer having a glass transition temperature of −80 ° C. or more and −50 ° C. or less as a homopolymer as a structural unit derived from a monomer other than a (meth) acrylic monomer having a carboxy group. It is preferable to have a structural unit (C) derived from and a structural unit (D) derived from a monomer having a glass transition temperature of 30 ° C. or higher and 120 ° C. or lower when a homopolymer is used.
The structural unit (C) derived from a monomer having a glass transition temperature of −80 ° C. or higher and −50 ° C. or lower when a homopolymer is used can contribute to film formation at a low temperature. That is, when the resin contains the structural unit (C), the resin particles melt when dried at a low temperature (for example, 60 ° C. or less), and a film having a smooth surface and a uniform thickness is easily formed.
Moreover, the structural unit (D) derived from a monomer having a glass transition temperature of 30 ° C. or higher and 120 ° C. or lower when a homopolymer is used can contribute to improvement of blocking resistance.
Therefore, when the resin has the structural unit (C) and the structural unit (D), the film-forming property at a low temperature derived from the structural unit (C) and the blocking resistance derived from the structural unit (D) are balanced. Since it is well expressed, a film having excellent blocking resistance can be formed even when dried at a low temperature.

  In this specification, “glass transition temperature when a homopolymer is used” means a glass transition temperature (Tg) represented by an absolute temperature (K) of a homopolymer produced by polymerizing the monomer alone. Say. The glass transition temperature of the homopolymer was measured using a differential scanning calorimeter (DSC) in a nitrogen stream under the conditions of a measurement sample of 10 mg and a heating rate of 10 ° C./min. The point is the glass transition temperature of the homopolymer.

The structural unit (C) is a structural unit derived from a monomer having a glass transition temperature of −80 ° C. or higher and −50 ° C. or lower when a homopolymer is used.
In the present specification, “a structural unit derived from a monomer having a glass transition temperature of −80 ° C. or more and −50 ° C. or less when a homopolymer is used” means a glass transition temperature of −80 when a homopolymer is used. It means a structural unit formed by addition polymerization of a monomer having a temperature of from ℃ to -50 ℃.

Although there is no restriction | limiting in particular as a kind of monomer whose glass transition temperature when it is set as a homopolymer is -80 degreeC or more and -50 degrees C or less, For example, the (meth) acryl monomer which has a carboxy group, and reactivity From the viewpoint of excellent copolymerizability with the surfactant, a (meth) acrylic acid alkyl ester monomer is preferable, and an unsubstituted (meth) acrylic acid alkyl ester monomer is preferable.
The alkyl group of the (meth) acrylic acid alkyl ester monomer may be linear, branched or cyclic. The range of 2-20 is preferable and, as for carbon number of an alkyl group, the range of 4-12 is more preferable.

Specific examples of monomers having a glass transition temperature of −80 ° C. or more and −50 ° C. or less when a homopolymer is used include 2-ethylhexyl acrylate (2EHA, Tg when a homopolymer is used: −76 ° C.), i-octyl acrylate (i-OA, Tg when a homopolymer is used: -75 ° C), n-octyl acrylate (n-OA, Tg when a homopolymer is used: -80 ° C), lauryl methacrylate (LMA) , Tg when a homopolymer is used: -65 ° C), n-butyl acrylate (n-BA, Tg when a homopolymer is used: -57 ° C), and the like.
Among these, as a monomer having a glass transition temperature of −80 ° C. or more and −50 ° C. or less when a homopolymer is used, for example, a (meth) acryl monomer having a carboxy group and a reactive surfactant From the viewpoint of being excellent in copolymerizability, at least one selected from 2-ethylhexyl acrylate (2EHA) and n-butyl acrylate (n-BA) is preferable.

The structural unit (D) is a structural unit derived from a monomer having a glass transition temperature of 30 ° C. or higher and 120 ° C. or lower when a homopolymer is used.
In the present specification, “a structural unit derived from a monomer having a glass transition temperature of 30 ° C. or higher and 120 ° C. or lower when a homopolymer is used” means a glass transition temperature of 30 ° C. or higher and 120 ° C. when a homopolymer is used. It means a structural unit formed by addition polymerization of a monomer having a temperature of 0 ° C. or lower.

The type of monomer having a glass transition temperature of 30 ° C. or higher and 120 ° C. or lower when it is a homopolymer is not particularly limited. For example, the glass transition temperature when a reactive surfactant and a homopolymer are used. (Meth) acrylic acid alkyl ester monomer is preferred from the viewpoint of excellent copolymerizability with a monomer having a temperature of -80 ° C. or higher and −50 ° C. or lower, and an unsubstituted (meth) acrylic acid alkyl ester monomer The body is preferred.
The alkyl group of the (meth) acrylic acid alkyl ester monomer may be linear, branched or cyclic. The range of 1-8 is preferable and, as for carbon number of an alkyl group, the range of 1-4 is more preferable.

Specific examples of monomers having a glass transition temperature of 30 ° C. or higher and 120 ° C. or lower when made as a homopolymer include methyl methacrylate (MMA, Tg when made as a homopolymer: 103 ° C.), i-butyl methacrylate ( i-BMA, Tg in the case of homopolymer: 53 ° C., t-butyl acrylate (t-BA, Tg in the case of homopolymer: 41 ° C.), t-butyl methacrylate (t-BMA, single weight Tg when combined: 107 ° C., isobornyl acrylate (Tg when homopolymer: 96 ° C.), i-propyl methacrylate (Tg when homopolymer: 81 ° C.), styrene (St, And a homopolymer of Tg: 90 ° C.).
Among these, as a monomer having a glass transition temperature of 30 ° C. or more and 120 ° C. or less when a homopolymer is used, for example, a glass transition temperature of −80 ° C. when a reactive surfactant and a homopolymer are used. Methyl methacrylate (MMA) is preferable from the viewpoint that it is more excellent in copolymerizability with a monomer of −50 ° C. or lower.

  The resin may have one of each of the structural unit (C) and the structural unit (D), has one of the structural unit (C) or the structural unit (D), and the other 2 You may have 2 or more types, and you may have 2 or more types of structural units (C) and structural units (D), respectively.

  When the resin has the structural unit (C) and the structural unit (D), the ratio of the structural unit (C) in the resin (that is, the content) is such that, for example, the film formability at a low temperature is expressed more favorably. From the viewpoint that the blocking resistance of the film derived from the unit (D) can be further improved, it is 20% by mass or more and 50% by mass with respect to the total mass of the structural units of the resin (excluding the structural unit (B)). % By mass or less is preferable, 25% by mass or more and 45% by mass or less is more preferable, and 30% by mass or more and 40% by mass or less is more preferable.

When the resin has a structural unit (C) and a structural unit (D), the ratio of the content of the structural unit (D) to the content of the structural unit (C) in the resin [content of structural unit (D) / structural unit The content of (C)] is preferably 2/1 to 1/4, more preferably 3/2 to 1/3, and still more preferably 1/1 to 1/2 on a mass basis.
The ratio of the content of the structural unit (D) to the content of the structural unit (C) in the resin [content of the structural unit (D) / content of the structural unit (C)] is within the above range on a mass basis. When it exists, it exists in the tendency for the more outstanding blocking-proof performance to be easy to be obtained.

<Constituent units derived from other monomers>
The resin is a monomer having a carboxy group, a monomer having a glass transition temperature of −80 ° C. or more and −50 ° C. or less, and a homopolymer, as long as the effect of the present invention is not impaired. And a structural unit derived from a monomer other than a monomer having a glass transition temperature of 30 ° C. or higher and 120 ° C. or lower (so-called other monomer).
For example, the resin may have a structural unit derived from a (meth) acrylic monomer having a hydroxyl group as a structural unit derived from another monomer.

<Structural unit (B)>
The resin has a structural unit (B) derived from a reactive surfactant, and the proportion of the structural unit (B) (that is, the content) is the structural unit of the resin (however, the structural unit (B) Is not less than 0.5% by mass and not more than 10% by mass with respect to the total mass.
In the present specification, the “structural unit derived from a reactive surfactant” means a structural unit formed by addition polymerization of a reactive surfactant.

The reactive surfactant is not particularly limited as long as it has an ethylenically unsaturated double bond.
The reactive surfactant may be an anionic reactive surfactant or a nonionic reactive surfactant. For example, fine particles of resin (specifically, average From the viewpoint that the particle diameter is easily controlled to 30 nm or more and 200 nm or less), an anionic reactive surfactant is preferable.

The ethylenically unsaturated double bond of the reactive surfactant is derived from a group having an ethylenically unsaturated double bond.
Specific examples of the group having an ethylenically unsaturated double bond include (meth) acryloyl group, vinyl group, allyl group, isopropenyl group, 1-propenyl group, allyloxy group, styryl group and the like.

The reactive surfactant preferably has an oxyalkylene group.
The reactive surfactant having an oxyalkylene group is excellent in copolymerizability with the monomer.
Examples of the oxyalkylene group include oxyalkylene groups having an alkylene group having 2 to 4 carbon atoms such as an oxyethylene group, an oxypropylene group, and an oxybutylene group.
Among these, as the oxyalkylene group, an oxyethylene group is preferable.
Since the oxyethylene group has higher hydrophilicity than, for example, an oxypropylene group or an oxybutylene group, a hydrated layer having a high density can be formed on the surface of the resin particles. Therefore, when the resin contains a structural unit derived from a reactive surfactant having an oxyethylene group, the dispersibility of the resin particles in the aqueous medium tends to be further increased.

The average added mole number of the oxyethylene group is not particularly limited, but is preferably 5 or more and 40 or less, and more preferably 10 or more and 30 or less.
When the average added mole number of the oxyethylene group is 5 or more and 40 or less, the copolymerizability with the monomer tends to be excellent.
Further, when the average added mole number of the oxyethylene group is 5 or more, the dispersibility of the resin particles in the aqueous medium tends to be further increased.

Preferred examples of the anionic reactive surfactant include an anionic reactive surfactant represented by the following formula (1) and an anionic reactive surfactant represented by the following formula (2). Can be mentioned.
Among these, as an anionic reactive surfactant, for example, from the viewpoint of industrial productivity, more specifically, a (meth) acrylic resin emulsion can be maintained at a low viscosity and excellent in handling properties, the following formula ( An anionic reactive surfactant represented by 1) is more preferred.

In Formula (1), R ^1a represents an aliphatic alkyl group having 6 to 24 carbon atoms, and X ^1a represents —SO ₃ NH ₄ or —SO ₃ Na.
In Formula (1), n1 represents the average number of added moles of oxyethylene groups (also referred to as “average number of repeating oxyethylene units”). n1 is an integer of 5 to 50, preferably an integer of 10 to 30.

  Examples of commercially available anionic reactive surfactants represented by formula (1) include Aqualon (registered trademark) KH-10 [active ingredient: polyoxyethylene-1- (allyloxymethyl) alkyl ether ammonium sulfate [ Average addition mole number of oxyethylene group: 10], active ingredient amount: 99% by mass, Daiichi Kogyo Seiyaku Co., Ltd.], Aqualon (registered trademark) KH-05 [active ingredient: polyoxyethylene-1- (allyloxy) Methyl) ammonium ether ether sulfate [average added mole number of oxyethylene group: 5], active ingredient amount: 99% by mass, Daiichi Kogyo Seiyaku Co., Ltd.], Adekaria Soap (registered trademark) SR-20 [active ingredient: poly Oxyethylene-1- (allyloxymethyl) alkyl ether ammonium sulfate [average added moles of oxyethylene group: 20], effective formation The amount: 100 wt%, and the like (Ltd.) ADEKA].

In the formula (2), R ^2a represents a substituent represented by the following formula (A) or an aliphatic alkyl group having 6 to 24 carbon atoms, and R ^3a represents a methyl group.
In Formula (2), X ^2a represents —SO ₃ M, —COOM, or PO ₃ M.
M represents an alkali metal atom, an alkaline earth metal atom, or an ammonium group.
Specific examples of the alkali metal atom include a sodium atom and a potassium atom.
Specific examples of the alkaline earth metal atom include a calcium atom and a barium atom.
As X ^2a , for example, —SO ₃ NH ₄ is preferable.
In the formula (2), n2 represents the average number of added moles of an oxyethylene group (also referred to as “average number of repeating oxyethylene units”). n2 is an integer of 5 to 50, preferably an integer of 10 to 30.

  In the formula (A), m represents an integer of 1 to 3, and for example, 2 is preferable from the viewpoint of surface activity.

  Examples of commercially available anionic reactive surfactants represented by the formula (2) include Aqualon (registered trademark) HS-10 [active ingredient: polyoxyethylene nonylpropenyl phenyl ether ammonium sulfate [average addition of oxyethylene groups] Mole number: 10], active ingredient amount: 99% by mass, Daiichi Kogyo Seiyaku Co., Ltd.], Aqualon (registered trademark) BC-10 [active ingredient: polyoxyethylene nonylpropenyl phenyl ether ammonium sulfate [average addition of oxyethylene group] Mole number: 10], active ingredient amount: 99% by mass, Daiichi Kogyo Seiyaku Co., Ltd.], Aqualon (registered trademark) BC-20 [active ingredient: polyoxyethylene nonylpropenyl phenyl ether ammonium sulfate [average addition of oxyethylene group] Mole number: 20], active ingredient amount: 99% by mass, Daiichi Kogyo Seiyaku Co., Ltd.] Quaron (registered trademark) AR-10 [active ingredient: ammonium polyoxyethylene styrenated propenyl phenyl ether sulfate [average added mole number of oxyethylene group: 10], active ingredient amount: 99% by mass, Daiichi Kogyo Seiyaku Co., Ltd. )], Aqualon (registered trademark) AR-20 [active ingredient: ammonium polyoxyethylene styrenated propenyl phenyl ether sulfate [average added moles of oxyethylene group: 20], active ingredient amount: 97% by mass, Daiichi Kogyo Pharmaceutical Co., Ltd.].

Preferred examples of the nonionic reactive surfactant include a nonionic reactive surfactant represented by the following formula (3) and a nonionic reactive surfactant represented by the following formula (4). Can be mentioned.
Among these, as the nonionic reactive surfactant, for example, a nonionic reactive surfactant represented by the following formula (3) is more preferable from the viewpoint of excellent copolymerizability with the monomer. .

In Formula (3), R ^1b represents an aliphatic alkyl group having 6 to 24 carbon atoms, and X ^1b represents a hydrogen atom.
In Formula (3), n3 represents the average number of moles of oxyethylene groups added (also referred to as “average number of repeating oxyethylene units”). n3 is an integer of 5 to 40, preferably an integer of 10 to 30.

  Examples of commercially available nonionic reactive surfactants represented by the formula (3) include ADEKA rear soap (registered trademark) ER-10 [active ingredient: polyoxyethylene-1- (allyloxymethyl) alkyl ether. [Average addition mole number of oxyethylene group: 10], amount of active ingredient: 100% by mass, ADEKA Co., Ltd., ADEKA rear soap (registered trademark) ER-30 [active ingredient: polyoxyethylene-1- (allyloxy) Methyl) alkyl ether [average added mole number of oxyethylene group: 30], active ingredient amount: 65% by mass, ADEKA Corporation, Adeka Soap (registered trademark) ER-40 [active ingredient: polyoxyethylene-1 -(Allyloxymethyl) alkyl ether [average number of moles of oxyethylene group added: 40], amount of active ingredient: 60% by mass, ADEKA CORPORATION And the like.

In Formula (4), R ^2b represents an aliphatic alkyl group having 6 to 24 carbon atoms, R ^3b represents a methyl group, and X ^2b represents a hydrogen atom.
In Formula (4), n4 represents the average number of moles of oxyethylene group added (also referred to as “average number of repeating oxyethylene units”). n4 is an integer of 10 to 50, preferably an integer of 10 to 30.

  Examples of commercially available nonionic reactive surfactants represented by formula (4) include Aqualon (registered trademark) RN-10 [active ingredient: polyoxyethylene nonylpropenyl phenyl ether [average addition mole of oxyethylene group] Number: 10], active ingredient amount: 99% by mass, Daiichi Kogyo Seiyaku Co., Ltd.], Aqualon (registered trademark) RN-30 [active ingredient: polyoxyethylene nonylpropenyl phenyl ether [average added mole number of oxyethylene group] : 30], active ingredient amount: 100% by mass, Daiichi Kogyo Seiyaku Co., Ltd.], Aqualon (registered trademark) RN-50 [active ingredient: polyoxyethylene nonylpropenyl phenyl ether [average added moles of oxyethylene group: 50], active ingredient amount: 65% by mass, Daiichi Kogyo Seiyaku Co., Ltd.] and the like.

The resin may have only one type of structural unit (B), or may have two or more types.
When the resin has two or more types of structural units (B), for example, the resin may have two or more types of structural units derived from an anionic reactive surfactant, and is derived from a nonionic reactive surfactant. It may have two or more structural units, and has a structural unit derived from one or more anionic reactive surfactants and a structural unit derived from one or more nonionic reactive surfactants. May be.

The proportion (that is, content) of the structural unit (B) in the resin is 0.5% by mass or more and 10% by mass or less based on the total mass of the structural unit of the resin (excluding the structural unit (B)). 1 mass% or more and 6 mass% or less are preferable, and 1 mass% or more and 3 mass% or less are more preferable.
The content of the structural unit (B) in the resin is 0.5% by mass or more based on the total mass of the structural units of the resin (excluding the structural unit (B)). It shows that it has B) positively.
When the content of the structural unit (B) in the resin is 10% by mass or less based on the total mass of the structural units of the resin (excluding the structural unit (B)), even when dried at a low temperature, Since the surface of the formed film exhibits hydrophobicity, a film having excellent water resistance can be formed.

-Average particle diameter of resin particles-
The average particle size of the resin particles is 30 nm to 200 nm, preferably 60 nm to 160 nm, and more preferably 80 nm to 120 nm.
When the average particle size of the resin particles is 30 nm or more, the industrial productivity is excellent.
When the average particle diameter of the resin particles is 200 nm or less, a film having excellent water resistance can be formed even when dried at a low temperature. When the particle diameter of the resin particles is large, voids are generated in the formed film. In the present invention, an average particle diameter of resin particles is 200 nm or less, and a film in which resin particles are densely packed can be formed. Since the formed film is dense, the water resistance of the film is excellent.

In the present specification, “average particle diameter of resin particles” means “New Experimental Chemistry Lecture 4 Basic Technology 3 Hikari (II)” pages 725 to 741 edited by the Chemical Society of Japan (July 20, 1977 Maruzen) It is the value measured by the dynamic light scattering method described in (Issuance Co., Ltd.). The specific method is as follows.
After the (meth) acrylic resin emulsion is diluted with deionized water and sufficiently stirred and mixed, 5 mL is collected using a Pasteur pipette in a 10 mm square glass cell, and this is set in a dynamic light scattering photometer. The set value of the attenuation rate (Attenuator) is set to x16 (16 times), and the concentration of the (meth) acrylic resin emulsion is adjusted so that the decay rate count rate is 150 kCps to 200 kCps, and then the measurement temperature is 25 ° C. ± The average particle diameter of the resin particles in the (meth) acrylic resin emulsion is determined by computer processing the results measured under conditions of 1 ° C. and a light scattering angle of 90 °. Moreover, the value of an average particle diameter uses the value of Z average.
As the dynamic light scattering photometer, for example, a dynamic light scattering photometer (trade name; Zetasizer Nano ZS90) manufactured by Malvern Co., Ltd. can be used.

-Glass transition temperature of resin-
The glass transition temperature of the resin is 0 ° C. or higher and 40 ° C. or lower, preferably 10 ° C. or higher and 40 ° C. or lower, and more preferably 15 ° C. or higher and 35 ° C. or lower.
When the glass transition temperature of the resin is 0 ° C. or higher, the coating film is not tacky, so that a film having excellent blocking resistance can be formed.
When the glass transition temperature of the resin is 40 ° C. or lower, the resin particles melt even when dried at a low temperature (for example, 60 ° C. or lower), so that the formed film becomes dense. Therefore, formation of a film having excellent water resistance can be realized.

In this specification, “glass transition temperature of resin” is a value measured by the following method using a differential scanning calorimetry (DSC).
The resin is applied onto the release paper using a 4 mil (101.6 μm) applicator. Next, the applied resin is dried (drying temperature: 105 ° C., drying time: 10 minutes) to obtain a dried resin product. The obtained dried product is used as a measurement sample. Next, 10 mg of the dried sample for measurement is packed in an aluminum sample pan [trade name: Tzero Pan, TA Instrument Co., Ltd.], and an aluminum lid [trade name: Tzero Hermetic Lid, TA Instrument Co., Ltd.] After sealing, the glass transition temperature is measured using a differential scanning calorimeter. The measurement conditions are shown below. The measurement is performed twice for the same sample, and the value obtained by the second measurement is adopted as the glass transition temperature of the resin.
As the differential scanning calorimeter, for example, a differential scanning calorimeter (trade name: DSC 6220) manufactured by Seiko Instruments Inc. can be used.

(Measurement condition)
Atmosphere conditions: Under air Measurement temperature range: -90 ° C to 100 ° C
Temperature rising rate: 20 ° C / min Standard material: Empty sample pan

-Content of resin particles-
The ratio (that is, the content) of the resin particles in the (meth) acrylic resin emulsion of the present invention is not particularly limited. The following is preferable, 30 mass% or more and 60 mass% or less are more preferable, and 45 mass% or more and 55 mass% or less are still more preferable.
When the content of the resin particles is 15% by mass or more based on the total mass of the (meth) acrylic resin emulsion, industrial productivity, more specifically, the (meth) acrylic resin emulsion can be maintained at a low viscosity, There is a tendency to be excellent in handling properties.
When the content of the resin particles is 65% by mass or less with respect to the total mass of the (meth) acrylic resin emulsion, the resin particles tend to be more difficult to aggregate.

[Aqueous medium]
The (meth) acrylic resin emulsion of the present invention contains an aqueous medium.
The aqueous medium contained in the (meth) acrylic resin emulsion of the present invention can function as a dispersion medium for resin particles.
The aqueous medium is not particularly limited and can be appropriately selected according to the purpose.
Examples of the aqueous medium include water, a mixed solution of water and an alcohol solvent, and the like.
As the aqueous medium, for example, water is preferable from the viewpoint of dispersibility of resin particles.
The content rate of the aqueous medium in the (meth) acrylic resin emulsion of the present invention is not particularly limited. For example, from the viewpoint of dispersion stability, 35 mass% or more and 85 mass% with respect to the total mass of the (meth) acrylic resin emulsion. % Or less, more preferably 40% by mass or more and 70% by mass or less, and further preferably 55% by mass or more and 45% by mass or less.

[Other ingredients]
The (meth) acrylic resin emulsion of the present invention may contain components other than those already described (so-called other components) as long as the effects of the present invention are not impaired.
Examples of other components include various additives such as a crosslinking agent, a film-forming aid, an antioxidant, an antistatic agent, a pH adjuster, and an antifoaming agent.

-PH of (meth) acrylic resin emulsion-
The pH of the (meth) acrylic resin emulsion of the present invention is preferably 2 to 10 from the viewpoint of the dispersibility of resin particles in an aqueous medium, for example.
The method for measuring the pH of the (meth) acrylic resin emulsion of the present invention is not particularly limited.
The pH of the (meth) acrylic resin emulsion of the present invention can be measured using, for example, a pH meter (trade name: F-51) manufactured by Horiba, Ltd., and a value measured at 25 ° C. is employed.

-Surface tension of (meth) acrylic resin emulsion-
The surface tension of the (meth) acrylic resin emulsion of the present invention is preferably from 35 mN / m to 65 mN / m, more preferably from 40 mN / m to 60 mN / m.
When the surface tension of the (meth) acrylic resin emulsion of the present invention is 35 mN / m or more, the permeability of the (meth) acrylic resin emulsion to paper is further suppressed, so that the function as a paper coating application is improved. Can demonstrate.
When the surface tension of the (meth) acrylic resin emulsion of the present invention is 65 mN / m or less, a more uniform film can be easily formed on paper.

In the present specification, “surface tension of (meth) acrylic resin emulsion” is a value measured by the following method using a surface tension meter.
The (meth) acrylic resin emulsion is diluted with deionized water, the solid content concentration is adjusted to 25% by mass, and a test solution is obtained. The surface tension of the obtained test solution is measured using a surface tension meter in an environment having an ambient temperature of 23 ° C. and a relative humidity of 55%.
As the surface tension meter, for example, a surface tension meter (trade name: automatic surface tension meter CBVP-Z type) manufactured by Kyowa Interface Science Co., Ltd. can be used.

[Method for producing (meth) acrylic resin emulsion]
The manufacturing method of the (meth) acrylic resin emulsion of the present invention is not particularly limited as long as the (meth) acrylic resin emulsion described above can be manufactured.
As a method for producing the (meth) acrylic resin emulsion of the present invention, for example, from the viewpoint that it is easy to produce the (meth) acrylic resin emulsion described above, the (meth) acrylic resin of the present embodiment described below will be described. An emulsion production method is preferred.

  The method for producing a (meth) acrylic resin emulsion of the present embodiment (hereinafter also referred to as “production method of the present embodiment”) has at least a carboxy group in the presence of a reactive surfactant and an aqueous medium (meta ) Acrylic monomer is polymerized to contain 0.1% by mass to 10% by mass of the structural unit (A) derived from the (meth) acrylic monomer having a carboxy group, and is reactive The structural unit (B) derived from the surfactant is contained in an amount of 0.5% by mass to 10% by mass relative to all the structural units, the glass transition temperature is 0 ° C. or higher and 40 ° C. or lower, and the average particle size is 30 nm The process of obtaining resin particles having a particle size of 200 nm or less (hereinafter also referred to as “emulsion polymerization process”) is included.

  Hereinafter, although each process in the manufacturing method of this embodiment is demonstrated, description is abbreviate | omitted about the detail which is common in the (meth) acrylic resin emulsion as stated above, for example, the detail of the component contained in a (meth) acrylic resin emulsion. To do.

<Emulsion polymerization process>
The emulsion polymerization step is a composition derived from a (meth) acrylic monomer having a carboxy group by polymerizing at least a (meth) acrylic monomer having a carboxy group in the presence of a reactive surfactant and an aqueous medium. The unit (A) is contained in an amount of 0.1% by mass to 10% by mass with respect to all the structural units, and the structural unit (B) derived from the reactive surfactant is contained in an amount of 0.5% by mass to 10% with respect to the total structural units. This is a step of obtaining resin particles containing not more than mass%, having a glass transition temperature of 0 ° C. or more and 40 ° C. or less, and an average particle size of 30 nm or more and 200 nm or less.
In the emulsion polymerization step, at least resin particles in which a (meth) acrylic monomer having a carboxy group and a reactive surfactant are copolymerized to form a hydrated layer formed on the surface of the reactive surfactant. can get.

It does not restrict | limit especially as a polymerization method, For example, the method of (1)-(3) shown below is mentioned.
(1) In a reaction vessel equipped with a thermometer, a stirring rod, a reflux condenser, a dropping funnel, etc., at least a (meth) acryl monomer having a carboxy group, a reactive surfactant, an aqueous medium, And heating the inside of the reaction vessel, and then appropriately adding a polymerization initiator, a reducing agent, etc. to advance the emulsion polymerization reaction (so-called batch charging method),
(2) After charging at least a reactive surfactant and an aqueous medium in a reaction vessel equipped with a thermometer, a stirring rod, a reflux condenser, a dropping funnel, etc., and raising the temperature in the reaction vessel, A method in which a monomer component (a (meth) acrylic monomer having at least a carboxy group) is dropped, and a polymerization initiator, a reducing agent, and the like are appropriately added to advance an emulsion polymerization reaction (so-called monomer dropping method);
(3) A monomer component (a (meth) acrylic monomer having at least a carboxy group) is pre-emulsified using at least a reactive surfactant and an aqueous medium to obtain a pre-emulsion, A method in which the obtained pre-emulsion is dropped into a reaction vessel equipped with a thermometer, a stirring rod, a reflux condenser, a dropping funnel, and the like, and a polymerization initiator, a reducing agent, etc. are appropriately added to advance the emulsion polymerization reaction. (So-called emulsified monomer dropping method) and the like.
Among these, as the polymerization method, for example, the emulsion monomer dropping method (3) is preferable from the viewpoint of industrial productivity.

The polymerization temperature is, for example, 50 ° C to 80 ° C, preferably 50 ° C to 70 ° C.
The polymerization time is, for example, 4 hours to 10 hours, preferably 4 hours to 8 hours.

The amount of the (meth) acrylic monomer having a carboxy group is not particularly limited, and is preferably 0.1 parts by mass or more, for example, 0.5 parts by mass or more with respect to 100 parts by mass of the total amount of monomers. Is more preferable.
The amount of the (meth) acrylic monomer having a carboxy group is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and more preferably 3 parts by mass with respect to 100 parts by mass of the total amount of monomers. The following is more preferable.
The amount of the reactive surfactant used is not particularly limited, and is preferably 0.5 parts by mass or more and more preferably 1 part by mass or more with respect to 100 parts by mass of the total amount of monomers.
The amount of the reactive surfactant used is, for example, preferably 10 parts by mass or less, more preferably 6 parts by mass or less, and still more preferably 3 parts by mass or less with respect to 100 parts by mass of the total amount of monomers.

In the emulsion polymerization step, a monomer having a glass transition temperature of −80 ° C. or more and −50 ° C. or less when a homopolymer is used, and a monomer having a glass transition temperature of 30 ° C. or more and 120 ° C. or less when a homopolymer is used. The amount of these monomers used can be adjusted so that the glass transition temperature of the resin constituting the finally obtained resin particles is 0 ° C. or higher and 40 ° C. or lower. preferable.
The amount of the monomer having a glass transition temperature of −80 ° C. or more and −50 ° C. or less when the homopolymer is used is, for example, 20 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the total amount of monomers. Is preferably 25 parts by mass or more and 45 parts by mass or less, and more preferably 30 parts by mass or more and 40 parts by mass or less.
The amount of the monomer having a glass transition temperature of 30 ° C. or higher and 120 ° C. or lower when the homopolymer is used is preferably 45 parts by mass or more and 75 parts by mass or less with respect to 100 parts by mass of the total amount of monomers. 50 parts by mass or more and 70 parts by mass or less are more preferable, and 55 parts by mass or more and 65 parts by mass or less are more preferable.

  In the emulsion polymerization step, various additives such as a polymerization initiator, a reducing agent, a chain transfer agent, and a pH adjuster may be used.

(Polymerization initiator)
Any polymerization initiator can be used without particular limitation as long as it can be used for ordinary emulsion polymerization.
Examples of the polymerization initiator include persulfates represented by ammonium persulfate, sodium persulfate, and potassium persulfate, organic peroxides represented by t-butyl hydroperoxide and cumene hydroperoxide, and hydrogen peroxide. Can be mentioned.
When a polymerization initiator is used in the emulsion polymerization step, only one polymerization initiator may be used, or two or more polymerization initiators may be used.

The polymerization initiator is used in an amount usually used.
The usage-amount of a polymerization initiator is 0.1 mass part-2 mass parts with respect to a total of 100 mass parts of the monomer which is a raw material, Preferably 0.3 mass part-1.5 mass parts It is.

(Reducing agent)
In the emulsion polymerization step, a reducing agent may be used together with the above-described polymerization initiator.
Examples of reducing agents include sodium metabisulfite, sodium sulfite, sodium bisulfite, sodium pyrosulfite (also referred to as “sodium disulfite”), sodium pyrophosphate, thioglycolic acid, sodium thiosulfate, ascorbic acid, tartaric acid, citric acid , Glucose and the like.
When a reducing agent is used in the emulsion polymerization step, only one reducing agent may be used, or two or more reducing agents may be used.

The reducing agent is used in an amount usually used.
The amount of the reducing agent used is, for example, 0.05 parts by mass to 2 parts by mass, preferably 0.2 parts by mass to 1.5 parts by mass with respect to a total of 100 parts by mass of the monomers as raw materials. is there.

<Other processes>
The manufacturing method of this embodiment may have processes other than an emulsion polymerization process as needed.

[film]
The membrane of the present invention has a structural unit (A) derived from a (meth) acrylic monomer having a carboxy group and a structural unit (B) derived from a reactive surfactant having an ethylenically unsaturated double bond. And the content rate of the said structural unit (A) is 0.1 to 10 mass% with respect to the total mass of a structural unit (however, except the said structural unit (B)), The said structural unit The content of (B) is 0.5 mass% or more and 10 mass% or less with respect to the total mass of the structural units (excluding the structural unit (B)), and the glass transition temperature is 0 ° C or higher and 40 ° C or higher. It includes a melt of resin particles having an average particle size of 30 nm or more and 200 nm or less.
The film of the present invention is excellent in water resistance and blocking resistance.

  The resin particles in the film of the present invention have the same meaning as the resin particles in the (meth) acrylic resin emulsion of the present invention described above, and the preferred embodiments are also the same, and thus the description thereof is omitted here.

The method for forming the film of the present invention is not particularly limited.
The film of the present invention can be formed, for example, by applying the above-described (meth) acrylic resin emulsion of the present invention on a paper substrate and then drying it.

The method for applying the (meth) acrylic resin emulsion of the present invention on a paper substrate is not particularly limited, and is a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, spray. The publicly known method using a coater etc. is mentioned.
The coating amount of the (meth) acrylic resin emulsion of the present invention on the paper substrate is appropriately set according to the thickness of the film to be formed.

There is no restriction | limiting in particular as a drying method, For example, heat drying, hot air drying, etc. are mentioned.
For example, the drying temperature is preferably 60 ° C. or lower, more preferably 55 ° C. or lower, and further preferably 50 ° C. or lower.
The drying time is not particularly limited, and is appropriately set depending on, for example, the thickness of the film to be formed, the amount of the aqueous medium in the (meth) acrylic resin emulsion of the present invention, and the like.

  The thickness of the film of the present invention is not particularly limited, and is, for example, preferably 50 nm to 5000 nm, and more preferably 300 nm to 1000 nm.

[Laminate]
The laminate of the present invention has the above-described film of the present invention on a paper substrate.
The laminate of the present invention is excellent in water resistance and blocking resistance.
The paper substrate is not particularly limited, and examples thereof include plain paper, high-quality paper, coated paper, and craft paper.
The thickness of a paper base material is not specifically limited, For example, it can be set as 5 micrometers-300 micrometers.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited to the following examples as long as the gist thereof is not exceeded.

  The pH of the (meth) acrylic resin emulsion produced in this example was measured by the measurement method described above.

[Production of (meth) acrylic resin emulsion]
[Example 1]
In a reaction vessel equipped with a thermometer, a stir bar, a reflux condenser, and a dropping funnel, 52.2 parts by mass of deionized water and “AQUALON (registered trademark) KH-10” which is an anionic reactive surfactant [Daiichi Kogyo Seiyaku Co., Ltd.] was charged with 0.5 part by mass, and the inside of the reaction vessel was purged with nitrogen.
Meanwhile, in another container, 30.8 parts by mass of deionized water and 1.5 parts by mass of “AQUALON (registered trademark) KH-10” [Daiichi Kogyo Seiyaku Co., Ltd.] which is an anionic reactive surfactant. 2-ethylhexyl acrylate (2EHA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg of a homopolymer] : -76 ° C] 34.0 parts by mass, and methyl methacrylate (MMA) as a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used [Tg when a homopolymer is used: 103 ° C. A pre-emulsion was prepared by adding 65.0 parts by mass and 1.0 part by mass of methacrylic acid (MAA) which is a (meth) acrylic monomer having a carboxy group.
Next, the internal temperature of the reaction vessel was raised to 60 ° C., 10.0 parts by mass of 10.0% by mass ammonium persulfate aqueous solution [polymerization initiator] and 8.0% by mass sodium disulfite aqueous solution [reducing agent] 1 0.0 part by mass was added to initiate the emulsion polymerization reaction.
Next, the pre-emulsion prepared above was added sequentially and uniformly over 3 hours, and 9.9 parts by mass of a 2.0% by mass ammonium persulfate aqueous solution [polymerization initiator] and 1.6% by mass sodium disulfite. 9.9 parts by mass of an aqueous solution [reducing agent] was added successively and uniformly over 3 hours and 30 minutes to effect emulsion polymerization.
30 minutes after the completion of the sequential addition of the polymerization initiator and the reducing agent, perbutyl (registered trademark) H-69 [69% by mass aqueous solution of t-butyl hydroperoxide, NOF Corporation, polymerization initiator] was further removed. 0.7 parts by mass of a 6.9% by mass t-butyl hydroperoxide aqueous solution prepared by diluting 10 times with ionic water and a 1.0% by mass L-ascorbic acid aqueous solution [reducing agent] 3.0% by mass Were uniformly added over 30 minutes and emulsion polymerization was performed to obtain an emulsion polymer. The obtained emulsion polymer was aged at 60 ° C. for 30 minutes and then cooled to room temperature to obtain a (meth) acrylic resin emulsion having a pH of 2.3. The solid content concentration of the obtained acrylic resin emulsion was 48.2% by mass.

[Example 2]
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.4 was obtained in the same manner as in Example 1 except that the preparation method of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.3% by mass.
“In another container, 30.8 parts by mass of deionized water and 1.5 parts by mass of“ AQUALON (registered trademark) KH-10 ”[Daiichi Kogyo Seiyaku Co., Ltd.] which is an anionic reactive surfactant , N-butyl acrylate (n-BA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less when used as a homopolymer [when used as a homopolymer] Tg: −57 ° C.] 41.0 parts by mass and a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used [methyl methacrylate (MMA) [Tg of a homopolymer: 103] C] 58.0 parts by mass and 1.0 part by mass of methacrylic acid (MAA) which is a (meth) acrylic monomer having a carboxy group were added and stirred to prepare a pre-emulsion. "

Example 3
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.5 was obtained in the same manner as in Example 1 except that the preparation method of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.2% by mass.
“In another container, 30.8 parts by mass of deionized water and 1.5 parts by mass of“ AQUALON (registered trademark) KH-10 ”[Daiichi Kogyo Seiyaku Co., Ltd.], which is an anionic reactive surfactant, , And then, 2-ethylhexyl acrylate (2EHA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg when making a homopolymer: -76 ° C.] 34.0 parts by mass and methyl methacrylate (MMA), which is a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used [Tg when a homopolymer is used: 103 ° C.] The pre-emulsion was prepared by putting and stirring 65.5 mass parts and 0.5 mass part of methacrylic acid (MAA) which is a (meth) acryl monomer which has a carboxy group. "

Example 4
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.1 was obtained in the same manner as in Example 1 except that the preparation method of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.1% by mass.
“In another container, 30.8 parts by mass of deionized water and 1.5 parts by mass of“ AQUALON (registered trademark) KH-10 ”[Daiichi Kogyo Seiyaku Co., Ltd.], which is an anionic reactive surfactant, , 2-ethylhexyl acrylate (2EHA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg when used as a homopolymer: -76 ° C.] 34.0 parts by mass and methyl methacrylate (MMA), which is a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used [Tg when a homopolymer is used: 103 ° C.] A pre-emulsion was prepared by adding and stirring 61.0 parts by mass and 5.0 parts by mass of methacrylic acid (MAA) which is a (meth) acrylic monomer having a carboxy group. "

Example 5
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.4 was obtained in the same manner as in Example 1 except that the preparation method of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.3% by mass.
“In another container, 30.8 parts by mass of deionized water and 1.5 parts by mass of“ AQUALON (registered trademark) KH-10 ”[Daiichi Kogyo Seiyaku Co., Ltd.], which is an anionic reactive surfactant, , 2-ethylhexyl acrylate (2EHA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg when used as a homopolymer: -76 ° C.] 34.0 parts by mass and methyl methacrylate (MMA), which is a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used [Tg when a homopolymer is used: 103 ° C.] A pre-emulsion was prepared by adding and stirring 65.0 parts by mass and 1.0 part by mass of acrylic acid (AA) which is a (meth) acrylic monomer having a carboxy group. "

Example 6
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.4 was obtained in the same manner as in Example 1 except that the operation until preparation of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.4% by mass.
“In a reaction vessel equipped with a thermometer, a stirring bar, a reflux condenser, and a dropping funnel, 52.2 parts by mass of deionized water and an anionic reactive surfactant“ AQUALON (registered trademark) KH-10 "Daiichi Kogyo Seiyaku Co., Ltd."
Meanwhile, in another container, 31.8 parts by mass of deionized water and 0.5 part by mass of “AQUALON (registered trademark) KH-10” [Daiichi Kogyo Seiyaku Co., Ltd.], which is an anionic reactive surfactant. And 2.0 parts by mass of “ADEKA rear soap (registered trademark) ER-10” [ADEKA], which is a nonionic reactive surfactant, were stirred, and then further made into a homopolymer. N-butyl acrylate (n-BA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg when used as a homopolymer: −57 ° C.] 42.0 parts by mass, Methyl methacrylate (MMA), which is a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when combined, and 57.0 parts by mass of Tg when formed as a homopolymer: 103 ° C., and having a carboxy group (meta ) Methacrylic acid (MAA), an acrylic monomer And 1.0 part by weight, by stirred into to prepare a pre-emulsion. "

Example 7
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.3 was obtained in the same manner as in Example 1 except that the preparation method of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.5% by mass.
“In another container, 31.0 parts by mass of deionized water and 1.5 parts by mass of“ AQUALON (registered trademark) KH-10 ”[Daiichi Kogyo Seiyaku Co., Ltd.], which is an anionic reactive surfactant, , And then, 2-ethylhexyl acrylate (2EHA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg when making a homopolymer: −76 ° C.] 31.0 parts by mass and a styrene (St) monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used [Tg when a homopolymer is used: 90 ° C.] 67 A pre-emulsion was prepared by adding 0.0 part by mass and 2.0 parts by mass of acrylic acid (AA) which is a (meth) acrylic monomer having a carboxy group. "

Example 8
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.3 was obtained in the same manner as in Example 1 except that the preparation method of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.3% by mass.
“In another container, 31.0 parts by mass of deionized water and 1.5 parts by mass of“ AQUALON (registered trademark) KH-10 ”[Daiichi Kogyo Seiyaku Co., Ltd.], which is an anionic reactive surfactant, , And then, 2-ethylhexyl acrylate (2EHA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg when making a homopolymer: -76 ° C.] 28.0 parts by mass and i-butyl methacrylate (i-BMA) which is a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used [Tg when a homopolymer is used. : 53 ° C.] 35.0 parts by mass and methyl methacrylate (MMA) [Tg as a homopolymer: 103 ° C.] 35.0 parts by mass and acrylic acid which is a (meth) acrylic monomer having a carboxy group (AA) 2.0 parts by mass By stirred into to prepare a pre-emulsion. "

Example 9
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.3 was obtained in the same manner as in Example 1 except that the preparation method of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.3% by mass.
“In another container, 31.0 parts by mass of deionized water and 1.5 parts by mass of“ AQUALON (registered trademark) KH-10 ”[Daiichi Kogyo Seiyaku Co., Ltd.], which is an anionic reactive surfactant, , Lauryl methacrylate (LMA), which is a monomer having a Tg of −80 ° C. to −50 ° C. [Tg of a homopolymer: −65]. ° C] 19.0 parts by mass and n-butyl acrylate (n-BA) [Tg in the case of a homopolymer: -57 ° C] 20.0 parts by mass and Tg in the case of a homopolymer of 30 ° C or more 60.0 parts by mass of methyl methacrylate (MMA) which is a monomer of 120 ° C. or less [Tg when homopolymer is 103 ° C.] and methacrylic acid which is a (meth) acrylic monomer having a carboxy group ( MAA) 1.0 parts by mass By stirring, to prepare a pre-emulsion. "

Example 10
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.3 was obtained in the same manner as in Example 1 except that the preparation method of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.3% by mass.
“In another container, 31.0 parts by mass of deionized water and 1.5 parts by mass of“ AQUALON (registered trademark) KH-10 ”[Daiichi Kogyo Seiyaku Co., Ltd.], which is an anionic reactive surfactant, , N-butyl acrylate (n-BA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less when used as a homopolymer [when used as a homopolymer] Tg: −57 ° C.] 33.0 parts by mass and methyl methacrylate (MMA) as a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when made as a homopolymer [Tg when made as a homopolymer: 103 ° C] 65.0 parts by mass and 2.0 parts by mass of acrylic acid (AA) which is a (meth) acrylic monomer having a carboxy group were added and stirred to prepare a pre-emulsion. "

Example 11
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.3 was obtained in the same manner as in Example 1 except that the preparation method of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.3% by mass.
“In another container, 31.0 parts by mass of deionized water and 1.5 parts by mass of“ AQUALON (registered trademark) KH-10 ”[Daiichi Kogyo Seiyaku Co., Ltd.], which is an anionic reactive surfactant, , N-butyl acrylate (n-BA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less when used as a homopolymer [when used as a homopolymer] Tg: −57 ° C.] 48.0 parts by mass and a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when the homopolymer is used [methyl methacrylate (MMA) [Tg when the homopolymer is used: 103] C] 51.0 parts by mass and 1.0 part by mass of methacrylic acid (MAA) which is a (meth) acrylic monomer having a carboxy group were added and stirred to prepare a pre-emulsion. "

Example 12
In the same manner as in Example 1, an emulsion polymer was obtained. The obtained emulsion polymer was aged at 60 ° C. for 30 minutes and then cooled to room temperature. Then, “Texanol (registered trademark) CS-12” [trade name, 2,2,4-trimethyl- 1,3-pentanediol monoisobutyrate, JNC Corporation] 3.0 parts by mass was added to obtain a (meth) acrylic resin emulsion having a pH of 2.5. The solid content concentration of the obtained acrylic resin emulsion was 49.1% by mass.

Example 13
In the same manner as in Example 2, an emulsion polymer was obtained. 2. The obtained emulsion polymer was aged at 60 ° C. for 30 minutes and then cooled to room temperature, and then “Epocross (registered trademark) WS-500” [oxazoline-based crosslinking agent, Nippon Shokubai Co., Ltd.], which is a crosslinking agent. 0 parts by mass was added to obtain a (meth) acrylic resin emulsion having a pH of 2.5. The solid content concentration of the obtained acrylic resin emulsion was 49.2% by mass.

Example 14
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.4 was obtained in the same manner as in Example 1 except that the operation until preparation of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.1% by mass.
“In a reaction vessel equipped with a thermometer, a stirring bar, a reflux condenser, and a dropping funnel, 52.2 parts by mass of deionized water and an anionic reactive surfactant“ AQUALON (registered trademark) KH-10 [Daiichi Kogyo Seiyaku Co., Ltd.] and 0.3 parts by mass were charged, and the inside of the reaction vessel was purged with nitrogen.
Meanwhile, in another container, 31.0 parts by mass of deionized water and 0.7 part by mass of “AQUALON (registered trademark) KH-10” [Daiichi Kogyo Seiyaku Co., Ltd.] which is an anionic reactive surfactant. 2-ethylhexyl acrylate (2EHA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg of a homopolymer] : -76 ° C.] 42.0 parts by mass, and methyl methacrylate (MMA), which is a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used [Tg when a homopolymer is used: 103 ° C. A pre-emulsion was prepared by adding 57.0 parts by mass and 1.0 part by mass of methacrylic acid (MAA) which is a (meth) acrylic monomer having a carboxy group. "

Example 15
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.3 was obtained in the same manner as in Example 1 except that the operation until preparation of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.2% by mass.
“In a reaction vessel equipped with a thermometer, a stirring bar, a reflux condenser, and a dropping funnel, 52.2 parts by mass of deionized water and an anionic reactive surfactant“ AQUALON (registered trademark) KH-10 [Daiichi Kogyo Seiyaku Co., Ltd.] 3.0 parts by mass, and the inside of the reaction vessel was purged with nitrogen.
On the other hand, in another container, 33.6 parts by mass of deionized water and 2.0 parts by mass of “AQUALON (registered trademark) KH-10” [Daiichi Kogyo Seiyaku Co., Ltd.] which is an anionic reactive surfactant. And, after stirring, n-butyl acrylate (n-BA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less when a homopolymer is obtained [when a homopolymer is obtained] Tg: −57 ° C.] 41.0 parts by mass, and a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used [methyl methacrylate (MMA) [Tg when a homopolymer is used: 103 ° C] 58.0 parts by mass and 1.0 part by mass of methacrylic acid (MAA) which is a (meth) acrylic monomer having a carboxy group were added and stirred to prepare a pre-emulsion. "

Example 16
In a reaction vessel equipped with a thermometer, a stir bar, a reflux condenser, and a dropping funnel, 52.2 parts by mass of deionized water and “AQUALON (registered trademark) KH-10” which is an anionic reactive surfactant [Daiichi Kogyo Seiyaku Co., Ltd.] was charged with 0.3 part by mass, and the inside of the reaction vessel was purged with nitrogen.
Meanwhile, in another container, 33.6 parts by mass of deionized water and 4.7 parts by mass of “AQUALON (registered trademark) KH-10” [Daiichi Kogyo Seiyaku Co., Ltd.] which is an anionic reactive surfactant. And, after stirring, n-butyl acrylate (n-BA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less when a homopolymer is obtained [when a homopolymer is obtained] Tg: −57 ° C.] 41.0 parts by mass, and a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used [methyl methacrylate (MMA) [Tg when a homopolymer is used: 103 ° C] 58.0 parts by mass and 1.0 part by mass of methacrylic acid (MAA) which is a (meth) acrylic monomer having a carboxy group were added and stirred to prepare a pre-emulsion.
Next, the internal temperature of the reaction vessel was raised to 60 ° C., and 5.0 parts by mass of 5.0 mass% ammonium persulfate aqueous solution [polymerization initiator] and 4.0 mass% sodium disulfite aqueous solution [reducing agent] 2 0.0 part by mass was added to initiate the emulsion polymerization reaction.
Next, the pre-emulsion prepared above was added sequentially and uniformly over 3 hours, and 5.0 parts by mass of 4.0% by mass ammonium persulfate aqueous solution [polymerization initiator] and 3.2% by mass sodium disulfite. An aqueous solution [reducing agent] of 5.0 parts by mass was added uniformly and successively over 3 hours and 30 minutes to carry out emulsion polymerization.
30 minutes after the completion of the sequential addition of the polymerization initiator and the reducing agent, perbutyl (registered trademark) H-69 [69% by mass aqueous solution of t-butyl hydroperoxide, NOF Corporation, polymerization initiator] was further removed. 0.8 parts by mass of a 6.9% by mass t-butyl hydroperoxide aqueous solution prepared by diluting 10 times with ionized water and a 1.0% by mass L-ascorbic acid aqueous solution [reducing agent] 3.0% by mass Were uniformly added over 30 minutes and emulsion polymerization was performed to obtain an emulsion polymer. The obtained emulsion polymer was aged at 60 ° C. for 30 minutes and then cooled to room temperature to obtain a (meth) acrylic resin emulsion having a pH of 2.4. The solid content concentration of the obtained acrylic resin emulsion was 49.4% by mass.

Example 17
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.5 was obtained in the same manner as in Example 1 except that the operation until preparation of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.3% by mass.
“In a reaction vessel equipped with a thermometer, a stirring rod, a reflux condenser, and a dropping funnel, 52.2 parts by mass of deionized water and an anionic reactive surfactant“ AQUALON AR-10 ” [Daiichi Kogyo Seiyaku Co., Ltd.] and 0.5 parts by mass were charged, and the inside of the reaction vessel was purged with nitrogen.
Meanwhile, in another container, 31.0 parts by mass of deionized water and 1.5 parts by mass of “AQUALON (registered trademark) AR-10” [Daiichi Kogyo Seiyaku Co., Ltd.] which is an anionic reactive surfactant. 2-ethylhexyl acrylate (2EHA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg of a homopolymer] : -76 ° C] 34.0 parts by mass, and methyl methacrylate (MMA) as a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used [Tg when a homopolymer is used: 103 ° C. A pre-emulsion was prepared by adding 65.0 parts by mass and 1.0 part by mass of methacrylic acid (MAA) which is a (meth) acrylic monomer having a carboxy group. "

Example 18
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.4 was obtained in the same manner as in Example 1 except that the operation until preparation of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.4% by mass.
“In a reaction vessel equipped with a thermometer, a stirring bar, a reflux condenser, and a dropping funnel, 52.2 parts by mass of deionized water and an anionic reactive surfactant“ AQUALON (registered trademark) KH-10 "Daiichi Kogyo Seiyaku Co., Ltd."
Meanwhile, in another container, 31.6 parts by mass of deionized water and 0.5 part by mass of “AQUALON (registered trademark) KH-10” [Daiichi Kogyo Seiyaku Co., Ltd.] which is an anionic reactive surfactant. And 2.0 parts by mass of Aqualon (registered trademark) RN-10 [Daiichi Kogyo Seiyaku Co., Ltd.], which is a nonionic reactive surfactant, and after stirring, the mixture is further made into a homopolymer. 2-ethylhexyl acrylate (2EHA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg when made as a homopolymer: −76 ° C.] 34.0 parts by mass, and a homopolymer Methyl methacrylate (MMA) which is a monomer having a Tg of 30 ° C. or higher and 120 ° C. or lower [Tg when homopolymer is 103 ° C.] 65.0 parts by mass, and a (meth) acrylic unit having a carboxy group Methacrylic acid (MAA) And 1.0 part by weight, by stirred into to prepare a pre-emulsion. "

Example 19
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.4 was obtained in the same manner as in Example 1 except that the operation until preparation of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.4% by mass.
“In a reaction vessel equipped with a thermometer, a stirring rod, a reflux condenser, and a dropping funnel, 52.2 parts by mass of deionized water and Aqualon (registered trademark) RN-10 [nonionic reactive surfactant] Daiichi Kogyo Seiyaku Co., Ltd.] 2.0 parts by mass were charged, and the inside of the reaction vessel was purged with nitrogen.
Meanwhile, in another container, 34.5 parts by mass of deionized water, 3.0 parts by mass of Aqualon (registered trademark) RN-10 [Daiichi Kogyo Seiyaku Co., Ltd.], which is a nonionic reactive surfactant, 2-ethylhexyl acrylate (2EHA), which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg when making a homopolymer: − 76 ° C.] 34.0 parts by mass and methyl methacrylate (MMA), which is a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used [Tg when a homopolymer is used: 103 ° C.] 65 A pre-emulsion was prepared by adding 0.0 part by mass and 1.0 part by mass of methacrylic acid (MAA) which is a (meth) acrylic monomer having a carboxy group. "

Example 20
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.5 was obtained in the same manner as in Example 1 except that the operation until preparation of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.3% by mass.
“In a reaction vessel equipped with a thermometer, a stirring bar, a reflux condenser, and a dropping funnel, 52.2 parts by mass of deionized water and an anionic reactive surfactant“ AQUALON (registered trademark) KH-10 [Daiichi Kogyo Seiyaku Co., Ltd.] and 0.3 parts by mass were charged, and the inside of the reaction vessel was purged with nitrogen.
Meanwhile, in a separate container, 31.7 parts by mass of deionized water and 0.7 part by mass of “AQUALON (registered trademark) KH-10” [Daiichi Kogyo Seiyaku Co., Ltd.] which is an anionic reactive surfactant. And 2.0 parts by mass of “AQUALON (registered trademark) AR-20” [Daiichi Kogyo Seiyaku Co., Ltd.], and after stirring, the Tg of the homopolymer is −80 ° C. or more— 2-ethylhexyl acrylate (2EHA) which is a monomer of 50 ° C. or lower [Tg when homopolymer is −76 ° C.] 34.0 parts by mass, and Tg when homopolymer is 30 ° C. or more and 120 65.0 parts by mass of methyl methacrylate (MMA) [Tg when homopolymer is a homopolymer: 103 ° C.] 65.0 parts by mass and a methacrylic acid (MAA) monomer having a carboxy group (MAA) ) 1.0 part by mass Doing, to prepare a pre-emulsion. "

Example 21
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.3 was obtained in the same manner as in Example 1 except that the operation until preparation of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.4% by mass.
“In a reaction vessel equipped with a thermometer, a stirring bar, a reflux condenser, and a dropping funnel, 52.2 parts by mass of deionized water and an anionic reactive surfactant“ AQUALON (registered trademark) KH-10 [Daiichi Kogyo Seiyaku Co., Ltd.] 0.4 parts by mass, and the inside of the reaction vessel was purged with nitrogen.
Meanwhile, in another container, 30.6 parts by mass of deionized water and 0.6 part by mass of “AQUALON (registered trademark) KH-10” [Daiichi Kogyo Seiyaku Co., Ltd.] which is an anionic reactive surfactant. And 3.1 parts by weight of “ADEKA rear soap (registered trademark) ER-30” (ADEKA), which is a nonionic reactive surfactant, were stirred, and then further made into a homopolymer. 2-ethylhexyl acrylate (2EHA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg when made as a homopolymer: −76 ° C.] 34.0 parts by mass, and a homopolymer Methyl methacrylate (MMA) which is a monomer having a Tg of 30 ° C. or higher and 120 ° C. or lower [Tg when made as a homopolymer: 103 ° C.] 65.0 parts by mass, and a (meth) acryl having a carboxy group Methacrylic acid as a monomer MAA) and 1.0 parts by mass by stirring put, to prepare a pre-emulsion. "

[Example 22]
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.0 was obtained in the same manner as in Example 1 except that the preparation method of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 48.9% by mass.
“In another container, 30.4 parts by mass of deionized water and 1.5 parts by mass of“ AQUALON (registered trademark) KH-10 ”[Daiichi Kogyo Seiyaku Co., Ltd.] which is an anionic reactive surfactant , And then, 2-ethylhexyl acrylate (2EHA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg when making a homopolymer: -76 ° C.] 34.0 parts by mass and methyl methacrylate (MMA), which is a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used [Tg when a homopolymer is used: 103 ° C.] A pre-emulsion was prepared by adding 58.0 parts by mass and 8.0 parts by mass of methacrylic acid (MAA) which is a (meth) acrylic monomer having a carboxy group. "

Example 23
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.4 was obtained in the same manner as in Example 1 except that the operation until preparation of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.2% by mass.
“In a reaction vessel equipped with a thermometer, a stirring bar, a reflux condenser, and a dropping funnel, 52.2 parts by mass of deionized water and an anionic reactive surfactant“ AQUALON (registered trademark) KH-10 "Daiichi Kogyo Seiyaku Co., Ltd."
Meanwhile, in another container, 36.6 parts by mass of deionized water and 2.5 parts by mass of “AQUALON (registered trademark) KH-10” [Daiichi Kogyo Seiyaku Co., Ltd.] which is an anionic reactive surfactant. And 5.0 parts by mass of “ADEKA rear soap (registered trademark) ER-10” [ADEKA], which is a nonionic reactive surfactant, were stirred, and then further made into a homopolymer. 2-ethylhexyl acrylate (2EHA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg in the case of a homopolymer: −76 ° C.] 34.0 parts by mass, Methyl methacrylate (MMA) which is a monomer having a Tg of 30 ° C. or higher and 120 ° C. or lower [Tg when homopolymer is 103 ° C.] 65.0 parts by mass, and a (meth) acryl having a carboxy group Methacrylic acid as a monomer MAA) and 1.0 parts by mass by stirring put, to prepare a pre-emulsion. "

[Comparative Example 1]
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.4 was obtained in the same manner as in Example 1 except that the preparation method of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.2% by mass.
“In a separate container, 30.4 parts by mass of deionized water and 1.5 parts by mass of“ AQUALON (registered trademark) KH-10 ”[Daiichi Kogyo Seiyaku Co., Ltd.], which is an anionic reactive surfactant, , N-butyl acrylate (n-BA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less when used as a homopolymer [when used as a homopolymer] Tg: −57 ° C.] 70.0 parts by mass and a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when the homopolymer is used [methyl methacrylate (MMA)] [Tg when the homopolymer is used: 103 C] 29.0 parts by mass and 1.0 part by mass of methacrylic acid (MAA) which is a (meth) acrylic monomer having a carboxy group were added and stirred to prepare a pre-emulsion. "

[Comparative Example 2]
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.4 was obtained in the same manner as in Example 1 except that the operation until preparation of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.3% by mass.
“In a reaction vessel equipped with a thermometer, a stirring bar, a reflux condenser, and a dropping funnel, 52.2 parts by mass of deionized water and“ Emar (registered trademark) 2FG ”which is an anionic non-reactive surfactant [Kao Co., Ltd.] 0.3 parts by mass and "DKS-NL 180" [Daiichi Kogyo Seiyaku Co., Ltd.] 0.2 parts by mass, which is a nonionic non-reactive surfactant, were charged into a reaction vessel. The inside was replaced with nitrogen.
On the other hand, in another container, 30.4 parts by mass of deionized water, 0.7 part by mass of “Emar (registered trademark) 2FG” [Kao Corporation], which is an anionic non-reactive surfactant, and a nonionic type After adding and stirring 0.8 parts by mass of “DKS-NL 180” [Daiichi Kogyo Seiyaku Co., Ltd.], which is a non-reactive surfactant, the Tg of the homopolymer is −80. 41.0 parts by mass of n-butyl acrylate (n-BA) [Tg as a homopolymer: −57 ° C.] which is a monomer having a temperature of from −50 ° C. to −50 ° C., and a Tg as a homopolymer Methyl methacrylate (MMA) which is a monomer having a temperature of 30 ° C. or more and 120 ° C. or less [Tg when homopolymer is 103 ° C.] 58.0 parts by mass, and a (meth) acryl monomer having a carboxy group A certain amount of methacrylic acid (MAA) A pre-emulsion was prepared by stirring. "

[Comparative Example 3]
In Example 1, a (meth) acrylic resin emulsion having a pH of 1.9 was obtained in the same manner as in Example 1 except that the preparation method of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.5% by mass.
“In a separate container, 30.4 parts by mass of deionized water and 1.5 parts by mass of“ AQUALON (registered trademark) KH-10 ”[Daiichi Kogyo Seiyaku Co., Ltd.], which is an anionic reactive surfactant, , N-butyl acrylate (n-BA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less when used as a homopolymer [when used as a homopolymer] Tg: −57 ° C.] 49.0 parts by mass and methyl methacrylate (MMA) which is a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used [Tg when a homopolymer is used: 103 C] 31.0 parts by mass and 20.0 parts by mass of methacrylic acid (MAA) which is a (meth) acrylic monomer having a carboxy group were added and stirred to prepare a pre-emulsion. "

[Comparative Example 4]
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.3 was obtained in the same manner as in Example 1 except that the preparation method of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.6% by mass.
“In a separate container, 30.4 parts by mass of deionized water and 1.5 parts by mass of“ AQUALON (registered trademark) KH-10 ”[Daiichi Kogyo Seiyaku Co., Ltd.], which is an anionic reactive surfactant, , And then, 2-ethylhexyl acrylate (2EHA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg when making a homopolymer: -76 ° C.] 20.0 parts by mass and methyl methacrylate (MMA) as a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used [Tg when a homopolymer is used: 103 ° C.] A pre-emulsion was prepared by adding 79.0 parts by mass and 1.0 part by mass of methacrylic acid (MAA), which is a (meth) acrylic monomer having a carboxy group, and stirring. "

[Comparative Example 5]
In a reaction vessel equipped with a thermometer, a stirring bar, a reflux condenser, and a dropping funnel, 52.2 parts by mass of deionized water was charged, and the inside of the reaction vessel was purged with nitrogen.
Meanwhile, in another container, 29.9 parts by mass of deionized water and 1.0 part by mass of “AQUALON (registered trademark) KH-10” [Daiichi Kogyo Seiyaku Co., Ltd.] which is an anionic reactive surfactant. 2-ethylhexyl acrylate (2EHA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg of a homopolymer] : -76 ° C.] 34.0 parts by mass, and a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when the homopolymer is used [methyl methacrylate (MMA) [Tg when using a homopolymer: 103 ° C.] A pre-emulsion was prepared by adding 65.0 parts by mass and 1.0 part by mass of methacrylic acid (MAA) which is a (meth) acrylic monomer having a carboxy group.
Next, the internal temperature of the reaction vessel was raised to 60 ° C., and 5.0 parts by mass of 5.0 mass% ammonium persulfate aqueous solution [polymerization initiator] and 4.0 mass% sodium disulfite aqueous solution [reducing agent] 2 0.0 part by mass was added to initiate the emulsion polymerization reaction.
Next, the pre-emulsion prepared above was added sequentially and uniformly over 3 hours, and 5.0 parts by mass of 4.0% by mass ammonium persulfate aqueous solution [polymerization initiator] and 3.2% by mass sodium disulfite. An aqueous solution [reducing agent] of 5.0 parts by mass was added uniformly and successively over 3 hours and 30 minutes to carry out emulsion polymerization.
30 minutes after the completion of the sequential addition of the polymerization initiator and the reducing agent, perbutyl (registered trademark) H-69 [69% by mass aqueous solution of t-butyl hydroperoxide, NOF Corporation, polymerization initiator] was further removed. 0.8 parts by mass of a 6.9% by mass t-butyl hydroperoxide aqueous solution prepared by diluting 10 times with ionized water and a 1.0% by mass L-ascorbic acid aqueous solution [reducing agent] 3.0% by mass Were uniformly added over 30 minutes and emulsion polymerization was performed to obtain an emulsion polymer. The obtained emulsion polymer was aged at 60 ° C. for 30 minutes and then cooled to room temperature to obtain a (meth) acrylic resin emulsion having a pH of 2.4. The resulting acrylic resin emulsion had a solid content concentration of 49.6% by mass.

[Comparative Example 6]
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.0 was obtained in the same manner as in Example 1 except that the preparation method of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.6% by mass.
“In another container, 31.0 parts by mass of deionized water and 1.5 parts by mass of“ AQUALON (registered trademark) KH-10 ”[Daiichi Kogyo Seiyaku Co., Ltd.], which is an anionic reactive surfactant, , And then, 2-ethylhexyl acrylate (2EHA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg when making a homopolymer: −76 ° C.] 34.0 parts by mass and a methyl methacrylate (MMA) monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used [Tg when a homopolymer is used: 103 ° C.] The pre-emulsion was prepared by putting and stirring 54.0 mass parts and 12.0 mass parts of methacrylic acid (MAA) which is a (meth) acryl monomer which has a carboxy group. "

[Comparative Example 7]
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.4 was obtained in the same manner as in Example 1 except that the preparation method of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.6% by mass.
“In another container, 31.0 parts by mass of deionized water and 1.5 parts by mass of“ AQUALON (registered trademark) KH-10 ”[Daiichi Kogyo Seiyaku Co., Ltd.], which is an anionic reactive surfactant, , And then, 2-ethylhexyl acrylate (2EHA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg when making a homopolymer: -76 ° C] 46.5 parts by mass and methyl methacrylate (MMA) which is a monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used [Tg when a homopolymer is used: 103 ° C.] A pre-emulsion was prepared by adding 52.5 parts by mass and 2.0 parts by mass of methacrylic acid (MMA) which is a (meth) acrylic monomer having a carboxy group. "

[Comparative Example 8]
In Example 1, a (meth) acrylic resin emulsion having a pH of 2.4 was obtained in the same manner as in Example 1 except that the operation until preparation of the pre-emulsion was changed as follows. The solid content concentration of the obtained (meth) acrylic resin emulsion was 49.4% by mass.
“In a reaction vessel equipped with a thermometer, a stirring bar, a reflux condenser, and a dropping funnel, 52.2 parts by mass of deionized water and an anionic reactive surfactant“ AQUALON (registered trademark) KH-10 [Daiichi Kogyo Seiyaku Co., Ltd.] 2.0 parts by mass, and the inside of the reaction vessel was purged with nitrogen.
Meanwhile, in another container, 41.3 parts by mass of deionized water and 3.0 parts by mass of “AQUALON (registered trademark) KH-10” [Daiichi Kogyo Seiyaku Co., Ltd.] which is an anionic reactive surfactant. And 8.0 parts by mass of “Adekaria Soap (registered trademark) ER-10” [ADEKA], which is a nonionic reactive surfactant, and stirred, and then a homopolymer. N-butyl acrylate (n-BA) which is a monomer having a Tg of −80 ° C. or more and −50 ° C. or less [Tg when used as a homopolymer: −57 ° C.] 41.0 parts by mass, Methyl methacrylate (MMA), which is a monomer having a Tg of 30 ° C. or higher and 120 ° C. or lower when combined, and 58.0 parts by mass of Tg when formed as a homopolymer: 103 ° C., and having a carboxy group (meta ) Methacrylic acid (MAA), an acrylic monomer And 1.0 part by weight, by stirred into to prepare a pre-emulsion. "

[Measurement and evaluation]
The following measurements and evaluations were performed using the (meth) acrylic resin emulsions of Examples 1 to 23 and Comparative Examples 1 to 8 obtained above. The results are shown in Tables 1 to 3.

1. Glass transition temperature of resin The glass transition temperature of the resin was measured by the following method using a differential scanning calorimeter (DSC).
The resin was applied onto the release paper using a 4 mil (101.6 μm) applicator. Next, the applied resin was dried (drying temperature: 105 ° C., drying time: 10 minutes) to obtain a dried resin. The obtained dried product was used as a measurement sample. Next, 10 mg of the dried sample for measurement is packed in an aluminum sample pan [trade name: Tzero Pan, TA Instrument Co., Ltd.], and an aluminum lid [trade name: Tzero Hermetic Lid, TA Instrument Co., Ltd.] After sealing, the glass transition temperature was measured using a differential scanning calorimeter [trade name: DSC 6220, Seiko Instruments Inc.]. The measurement conditions are shown below. The measurement was performed twice for the same sample, and the value obtained by the second measurement was adopted as the glass transition temperature of the resin.

-Measurement conditions-
Atmosphere conditions: Under air Measurement temperature range: -90 ° C to 100 ° C
Temperature rising rate: 20 ° C / min Standard material: Empty sample pan

2. Average particle diameter of resin particles (Meth) Acrylic resin emulsion is diluted with deionized water and mixed well with stirring. After that, 5 mL is collected in a 10 mm square glass cell using a Pasteur pipette, and this is used as dynamic light. A scattering photometer [trade name: Zetasizer Nano ZS90, Malvern Co., Ltd.] was used. The set value of the attenuation rate (Attenuator) is set to x16 (16 times), and the concentration of the (meth) acrylic resin emulsion is adjusted so that the decay rate count rate is 150 kCps to 200 kCps, and then the measurement temperature is 25 ° C. ± The average particle diameter of the resin particles in the (meth) acrylic resin emulsion was determined by computer processing the results measured under conditions of 1 ° C. and a light scattering angle of 90 °. Moreover, the value of average particle diameter used the value of Z average.

3. Water Resistance (1) Preparation of Evaluation Sample A (meth) acrylic resin emulsion was diluted with deionized water to adjust the solid content concentration to 40% by mass to obtain a test solution.
The obtained test solution was applied to one side of a paper [trade name: OK Prince fine paper, Oji Paper Co., Ltd.] using wire No. 2 [Daiichi Rika Co., Ltd.] (Amount of test solution applied) : About 2.4 g / m ² ). Next, the coated test solution was dried (drying temperature: 50 ° C., drying time: 30 seconds) to obtain a paper having one surface coated (coated) with a film. Subsequently, a film was formed by performing the same operation as described above on the surface of the obtained paper where the film was not formed, and a paper having both sides coated (coated) was obtained. The obtained paper was used as a water resistance evaluation sample.

(2) Evaluation test The degree of sizing of the evaluation sample obtained above was measured by a method in accordance with JIS P 8122: 2004 "Paper and paperboard-Sizing degree test method-Steech human method", and according to the following evaluation criteria. The water resistance was evaluated. “Size” means the penetration resistance of water, and is expressed in time (unit: seconds) required for coloring. In addition, the time required for coloration of the paper [trade name: OK Prince fine paper, Oji Paper Co., Ltd.] having no film formed on the surface was 15 seconds.
The (meth) acrylic resin emulsion capable of forming a film having excellent water resistance is classified as “5”, “4”, or “3”, and the most excellent evaluation is “5”.

(Evaluation criteria)
5: The time required for coloring is 300 seconds or more.
4: The time required for coloring is 225 seconds or more and less than 300 seconds.
3: Time required for coloring is 150 seconds or more and less than 225 seconds.
2: The time required for coloring is 75 seconds or more and less than 150 seconds.
1: Time required for coloring is less than 75 seconds.

4). Blocking Resistance (1) Preparation of Evaluation Sample A (meth) acrylic resin emulsion was diluted with deionized water, the solid content concentration was adjusted to 40% by mass, and a test solution was obtained.
The obtained test solution was applied to one side of a paper [trade name: OK Prince fine paper, Oji Paper Co., Ltd.] using wire No. 2 [Daiichi Rika Co., Ltd.] (Amount of test solution applied) : About 2.4 g / m ² ). Next, the coated test solution was dried (drying temperature: 50 ° C., drying time: 30 seconds) to obtain a paper having one surface coated (coated) with a film. The obtained paper was used as an evaluation sample for blocking resistance.

(2) Evaluation test Using the evaluation sample obtained above, an evaluation test for blocking resistance was performed. The evaluation test method will be described with reference to the drawing (FIG. 1).
Two mortar plates (size: 7 cm × 15 cm) [mortar plate A (10A) and mortar plate B (10B)] and two smooth SUS (stainless steel) plates (size: 5 cm × 10 cm) [stainless steel plate A ( 20A) and stainless steel plate B (20B)] and paper cut into a size of 2 cm × 5 cm [trade name: OK Prince fine paper, Oji Paper Co., Ltd.] 1 sheet (30) and a size of 2 cm × 5 cm An anti-blocking evaluation sample (40) was prepared.
In order from the top, mortar plate A (10A) / smooth SUS plate A (20A) / paper (30) / evaluation sample (40) [film / paper] / smooth SUS plate B (20B) / mortar plate B (10B) Overlapped so that. Note that the surface of the paper (30) and the evaluation sample (40) on which the film of the paper (30) and the evaluation sample (40) is formed so that half of the mutual area (2 cm × 2.5 cm) is in contact with the paper (30). Were placed facing each other.
Next, as shown in FIGS. 1 (A) and 1 (B), a weight (W) is placed on the mortar plate A (10A) so as to have a load of 500 g / cm ² , and the ambient temperature is 23 ° C. For 100 hours. After standing, the mortar board A (10A), the mortar board B (10B), the smooth SUS board A (20A), and the smooth SUS board B (20B) are overlapped with the paper (30) and the evaluation sample (40). It was removed so that it would not be damaged. Subsequently, the part which did not overlap with the evaluation sample (40) of paper (30) was picked up with the finger, and blocking resistance was evaluated according to the following evaluation criteria.
The (meth) acrylic resin emulsion capable of forming a film having excellent blocking resistance is classified as “3” or “2”, and the most excellent evaluation is “3”.

(Evaluation criteria)
3: The evaluation sample easily peels off with its own weight.
2: The evaluation sample does not peel off with its own weight, but peels off when a little force is applied.
1: The evaluation sample is difficult to peel off or does not peel off.

5. Surface tension The (meth) acrylic resin emulsion was diluted with deionized water, the solid content concentration was adjusted to 25% by mass, and a test solution was obtained.
The surface tension of the obtained test solution is measured using a surface tension meter (trade name: automatic surface tension meter CBVP-Z type, Kyowa Interface Science Co., Ltd.) in an environment with an ambient temperature of 23 ° C. and a relative humidity of 55%. did.

In Tables 1 to 3, “-” means that the corresponding component is not blended.
The compounding quantity of surfactant shown to Table 1-Table 3 is an active ingredient conversion value.

Details of each component described in Tables 1 to 3 are as shown below.
<Monomer>
(Monomer having Tg of −80 ° C. or more and −50 ° C. or less as a homopolymer)
“2EHA”: 2-ethylhexyl acrylate [Tg when a homopolymer is used: −76 ° C.]
“LMA”: lauryl methacrylate [Tg when made into a homopolymer: −65 ° C.]
“N-BA”: n-butyl acrylate [Tg when a homopolymer is used: −57 ° C.]
(Monomer having a Tg of 30 ° C. or more and 120 ° C. or less when a homopolymer is used)
“St”: Styrene [Tg when a homopolymer is used: 90 ° C.]
“I-BMA”: i-butyl methacrylate [Tg when a homopolymer is used: 53 ° C.]
“MMA”: methyl methacrylate [Tg when homopolymer is used: 103 ° C.]
((Meth) acrylic monomer having carboxy group)
“AA”: Acrylic acid [Tg when made into a homopolymer: 163 ° C.]
“MAA”: methacrylic acid [Tg when homopolymer is formed: 185 ° C.]

<Reactive surfactant>
(Anionic reactive surfactant)
“KH-10”: Aqualon (registered trademark) KH-10 [active ingredient: polyoxyethylene-1- (allyloxymethyl) alkyl ether ammonium sulfate [type of oxyalkylene group: oxyethylene group, average number of added moles: 10], active ingredient amount: 99 mass%, Daiichi Kogyo Seiyaku Co., Ltd., anionic reactive surfactant represented by formula (1)]
“AR-10”: Aqualon (registered trademark) AR-10 [active ingredient: ammonium polyoxyethylene styrenated propenyl phenyl ether sulfate [type of oxyalkylene group: oxyethylene group, average number of added moles: 10], active ingredient Amount: 99% by mass, Daiichi Kogyo Seiyaku Co., Ltd., an anionic reactive surfactant represented by formula (2)]
“AR-20”: Aqualon (registered trademark) AR-20 [active ingredient: ammonium polyoxyethylene styrenated propenyl phenyl ether sulfate [type of oxyalkylene group: oxyethylene group, average number of added moles: 20], active ingredient Amount: 97% by mass, Daiichi Kogyo Seiyaku Co., Ltd., an anionic reactive surfactant represented by formula (2)]
(Nonionic type reactive surfactant)
“ER-10”: ADEKA rear soap (registered trademark) ER-10 [active ingredient: polyoxyethylene-1- (allyloxymethyl) alkyl ether [type of oxyalkylene group: oxyethylene group, average number of added moles: 10 ] Active ingredient amount: 100% by mass, ADEKA Co., Ltd., an anionic reactive surfactant represented by formula (3)]
“ER-30”: ADEKA rear soap (registered trademark) ER-30 [active ingredient: polyoxyethylene-1- (allyloxymethyl) alkyl ether [type of oxyalkylene group: oxyethylene group, average number of added moles: 30] ] Active ingredient amount: 65% by mass, ADEKA Corporation, an anionic reactive surfactant represented by formula (3)]
“RN-10”: Aqualon (registered trademark) RN-10 [active ingredient: polyoxyethylene nonylpropenyl phenyl ether [type of oxyalkylene group: oxyethylene group, average number of added moles: 10], active ingredient amount: 99 mass %, Daiichi Kogyo Seiyaku Co., Ltd., an anionic reactive surfactant represented by formula (4)]

<Non-reactive surfactant>
(Anionic non-reactive surfactant)
“2FG”: Emar (registered trademark) 2FG [active ingredient: sodium lauryl sulfate, amount of active ingredient: 98% by mass, Kao Corporation]
(Nonionic non-reactive surfactant)
“DKS-NL 180”: DKS-NL 180 [trade name, active ingredient: polyoxyethylene lauryl ether, active ingredient amount: 100 mass%, Daiichi Kogyo Seiyaku Co., Ltd.]
<Crosslinking agent>
"WS-500": Epocross (registered trademark) WS-500 [Oxazoline-based crosslinking agent, Nippon Shokubai Co., Ltd.]
<Filming aid>
“Texanol”: Texanol (registered trademark) CS-12 [active ingredient: 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, JNC Corporation]

  As shown in Table 1 and Table 2, when the (meth) acrylic resin emulsions of Examples 1 to 23 are both dried at a low temperature of 50 ° C., a film excellent in both water resistance and blocking resistance is obtained. I was able to form.

On the other hand, as shown in Table 3, the films formed of the (meth) acrylic resin emulsions of Comparative Example 1 and Comparative Example 7 in which the glass transition temperature of the resin is less than 0 ° C. have a glass transition temperature of 0 ° C. or higher. Compared with the film | membrane formed with the (meth) acrylic resin emulsion of the Example (for example, Example 2) 40 degrees C or less, blocking resistance was inferior.
The film formed from the (meth) acrylic resin emulsion of Comparative Example 2 using a non-reactive surfactant instead of a reactive surfactant used a reactive surfactant (that is, a reactive surfactant). Compared with the film | membrane formed with the (meth) acrylic resin emulsion of the Example (for example, Example 2) which has the structural unit (B) originating in (2), water resistance was inferior.
The content of the structural unit (A) derived from the (meth) acrylic monomer having a carboxy group in the resin is 10% by mass with respect to the total mass of the structural unit (excluding the structural unit (B)). The film formed of the (meth) acrylic resin emulsion of Comparative Example 3 and Comparative Example 6 that exceeds the content of the structural unit (A) derived from the (meth) acrylic monomer having a carboxy group in the resin is a structural unit ( However, it was formed by the (meth) acrylic resin emulsion of Example (for example, Example 2) which is 0.1 mass% or more and 10 mass% or less with respect to the total mass of the said structural unit (B). Compared to the membrane, the water resistance was inferior.
The film formed by the (meth) acrylic resin emulsion of Comparative Example 4 in which the glass transition temperature of the resin exceeds 40 ° C. is that of the example (for example, Example 1) in which the glass transition temperature of the resin is 0 ° C. or more and 40 ° C. or less. Compared with the film | membrane formed with the (meth) acrylic resin emulsion, water resistance was inferior.
The film formed of the (meth) acrylic resin emulsion of Comparative Example 5 in which the average particle size of the resin particles exceeds 200 nm is an example in which the average particle size of the resin particles is 30 nm to 200 nm (for example, Example 14). The water resistance was inferior to that of the film formed from the (meth) acrylic resin emulsion.
In Comparative Example 8, the content of the structural unit (B) derived from the reactive surfactant in the resin exceeds 10% by mass with respect to the total mass of the structural unit (excluding the structural unit (B)). In the film formed of the (meth) acrylic resin emulsion, the content of the structural unit (B) derived from the reactive surfactant in the resin is the total mass of the structural unit (excluding the structural unit (B)). On the other hand, compared with the film | membrane formed with the (meth) acrylic resin emulsion of the Example (for example, Example 15) which is 0.5 mass% or more and 10 mass% or less, blocking resistance was inferior.

10A Mortar board A
10B Mortar board B
20A Smooth SUS board A
20B Smooth SUS board B
30 Paper 40 Evaluation sample W Weight

Claims (6)

A structural unit (A) derived from a (meth) acrylic monomer having a carboxy group and a structural unit (B) derived from a reactive surfactant having an ethylenically unsaturated double bond, the structural unit ( The content of A) is 0.1% by mass or more and 10% by mass or less with respect to the total mass of the structural unit (excluding the structural unit (B)), and the content of the structural unit (B). Is 0.5 mass% to 10 mass% with respect to the total mass of the structural units (excluding the structural unit (B)), and the glass transition temperature is 0 ° C. or higher and 40 ° C. or lower, and Resin particles having an average particle diameter of 30 nm or more and 200 nm or less;
An aqueous medium;
(Meth) acrylic resin emulsion for paper coating containing   The structural unit (C) derived from a monomer having a glass transition temperature of −80 ° C. or more and −50 ° C. or less when the resin is a homopolymer, and the glass transition temperature when the resin is a homopolymer is 30 ° C. The (meth) acrylic resin emulsion for paper coating of Claim 1 which has a structural unit (D) derived from the monomer above 120 degreeC.   The (meth) acrylic resin emulsion for paper coating according to claim 1 or 2, wherein the reactive surfactant is an anionic reactive surfactant.   The (meth) acrylic resin emulsion for paper coating according to any one of claims 1 to 3, wherein the reactive surfactant has an oxyalkylene group having an average addition mole number of 5 or more and 40 or less.   A structural unit (A) derived from a (meth) acrylic monomer having a carboxy group and a structural unit (B) derived from a reactive surfactant having an ethylenically unsaturated double bond, The content of A) is 0.1% by mass or more and 10% by mass or less with respect to the total mass of the structural unit (excluding the structural unit (B)), and the content of the structural unit (B). Is 0.5 mass% to 10 mass% with respect to the total mass of the structural units (excluding the structural unit (B)), the glass transition temperature is 0 ° C. or higher and 40 ° C. or lower, and A film containing a melt of resin particles having an average particle size of 30 nm to 200 nm.   A laminate having the film according to claim 5 on a paper substrate.