JP2017171900A - Polymer emulsion, manufacturing method therefor, coating agent composition for synthetic paper and coated synthetic paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer emulsion capable of enhancing water resistance while suppressing reduction of antistatic performance, a coating agent composition for synthetic paper using the same, a coated synthetic paper using the same and a manufacturing method of the polymer emulsion.SOLUTION: There is provided a polymer emulsion 1 by dispersing core shell type polymer particles 2 having a shell part 21 consisting of a specific cationic polymer and a core part 22 consisting of specific hydrophobic polymer in an aqueous medium 10. There is provided a coating agent composition for synthetic paper containing the polymer emulsion 1. There is further provided a coated synthetic paper having synthetic paper consisting of a synthetic resin film or a synthetic resin and a coated film consisting of the coating agent composition for synthetic paper formed on one or both surface thereof.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polymer emulsion in which core-shell type polymer particles are dispersed in an aqueous medium, a method for producing the same, a coating composition for synthetic paper containing the polymer emulsion, and a coated synthetic paper coated with the coating composition. .

  Synthetic paper made of synthetic resin films, synthetic fibers, and the like is manufactured using synthetic resin obtained from petroleum or the like as a main raw material. Synthetic paper combines the properties of paper and plastic, and is generally superior in terms of durability, water resistance, production cost, and the like, compared to natural paper made of vegetable fibers (ie, pulp). Therefore, synthetic paper is widely used not only for outdoor printing paper such as posters, but also for indoor printing paper such as catalogs, business cards, and various labels.

  On the other hand, synthetic paper has the property of being easily charged because it is made of synthetic resin. Charging is likely to occur in a dry environment with low humidity. The charging of the synthetic paper may cause dust and paper dust to adhere, and may cause a paper feed failure in the printing press. Further, for example, in offset printing, since the synthetic paper is easily dried during printing, troubles due to charging of the synthetic paper tend to occur. Specifically, there is a possibility that printing troubles such as paper feed failure, paper discharge failure, and ink smear will occur.

  Therefore, there is a technique for applying an antistatic agent to the surface of the synthetic paper. For example, a coating composition for synthetic paper made of a surface-treating polymer obtained by cationizing N atoms in a copolymer having a predetermined structure has been developed (see Patent Document 1). Further, in order to prevent the synthetic paper from being charged, a conductive agent made of a cationic polymer or copolymer having a predetermined repeating unit as a support has been developed (see Patent Document 2). In addition, a thermoplastic resin film having a coating film of a quaternary ammonium salt copolymer having a predetermined structure has been developed (see Patent Document 3).

JP 50-145476 A JP-A-53-8380 JP-A-6-25447

  However, although cationic polymers and copolymers can increase the electrical conductivity of synthetic paper and prevent electrical resistance, further improvements in water resistance are desired. That is, the coating film formed on the surface of the synthetic paper may be washed away by water. As a result, there is a possibility that the ink of the printed matter may flow down together with the coating film. Accordingly, development of a coating composition for synthetic paper that has both good antistatic performance and water resistance is desired.

  An object of the present invention is to provide a polymer emulsion capable of improving the water resistance while suppressing a decrease in the antistatic performance of the synthetic paper, a coating composition for synthetic paper using the same, and a coated synthetic paper using the polymer emulsion And a method for producing a polymer emulsion.

  As a result of intensive studies to solve the above problems, the present inventors have found that a core-shell type polymer particle having a shell part made of a cationic polymer having a predetermined structure and a core part made of a hydrophobic polymer is aqueous. The present inventors have found that the polymer emulsion dispersed in the medium can improve the water resistance while suppressing the decrease in the antistatic performance, and have reached the present invention. That is, the gist of the present invention is the following [1] to [20].

[1] A polymer emulsion in which core-shell type polymer particles having a shell part made of a cationic polymer (A) and a core part made of a hydrophobic polymer (B) are dispersed in an aqueous medium,
The cationic polymer (A) includes a monomer-derived structural unit (a1) represented by the following formula (I), and a monomer-derived structural unit (a2) represented by the following formula (II): Comprising a copolymer having
The hydrophobic polymer (B) is a polymer emulsion having a structural unit (b) derived from a hydrophobic unsaturated monomer.
^{_{CH 2 = C (R 1)}} COZR 2 N + R 3 R 4 (R 5 N + R 6 R 7) n -R 8 · (n + 1) X - ··· (I)
(In the formula (I), R ¹ is a hydrogen atom or a methyl group, Z is —O— or —NH—, and R ² and R ⁵ are each independently an alkylene group having 1 to 6 carbon atoms. R ³ , R ⁴ , R ⁶ and R ⁷ are each independently a methyl group or an ethyl group, and R ⁸ is an alkyl group having 1 to 10 carbon atoms or a group having 7 to 10 carbon atoms. An aralkyl group, X is a halogen atom, and n is an integer of 0 to 3.)
CH ₂ = C (R ⁹ ) COOR ¹⁰ (II)
(In Formula (II), R ⁹ is a hydrogen atom or a methyl group, and R ¹⁰ is an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 20 carbon atoms.)

[2] The polymer emulsion according to [1], wherein in the formula (1), n = 1.

[3] The polymer emulsion according to [1] or [2], wherein, in the formula (I), R ² is CH ₂ CH ₂ and R ⁵ is CH ₂ CH (OH) CH ₂ .

[4] The content of the structural unit (a1) in the copolymer is 20 to 50% by mass, and the content of the structural unit (a2) is 80 to 50% by mass. ] The polymer emulsion of any one of.

[5] The polymer emulsion according to any one of [1] to [4], wherein a glass transition temperature Tg _B of the hydrophobic polymer (B) is lower than a glass transition temperature Tg _A of the cationic polymer (A).

[6] The polymer emulsion according to any one of [1] to [5], wherein an average particle size of the core-shell type polymer particles is 150 nm or less.

[7] The polymer emulsion according to any one of [1] to [6], wherein a main component of the hydrophobic unsaturated monomer is a (meth) acrylic acid ester.

[8] A polymer emulsion in which core-shell type polymer particles having a shell part made of a cationic polymer (C) and a core part made of a hydrophobic polymer (B) are dispersed in an aqueous medium,
The cationic polymer (C) includes a monomer-derived structural unit (c1) represented by the following formula (III), and a monomer-derived structural unit (c2) represented by the following formula (II). Comprising a copolymer having
The content of the structural unit (c1) in the copolymer is 20 to 50% by mass, the content of the structural unit (c2) is 80 to 50% by mass,
The cationic polymer (C) has a glass transition temperature Tg _C of 40 to 85 ° C.,
The hydrophobic polymer (B) has a structural unit (b) derived from a hydrophobic unsaturated monomer,
A polymer emulsion in which the glass transition temperature Tg _B of the hydrophobic polymer (B) is lower than the glass transition temperature Tg _{C of the} cationic polymer (C).
^{_{CH 2 = C (R 1)}} COZR 2 N + R 3 R 4 -CH 2 COOR 8 · X - ··· (III)
(In the formula (III), R ¹ is a hydrogen atom or a methyl group, Z is —O— or —NH—, and R ² is an alkylene group having 1 to 6 carbon atoms and containing a hydroxyl group. R ³ and R ⁴ are each independently a methyl group or an ethyl group, R ⁸ is an alkyl group having 1 to 10 carbon atoms or an aralkyl group having 7 to 10 carbon atoms, and X is a halogen atom. )
CH ₂ = C (R ⁹ ) COOR ¹⁰ (II)
(In the formula (II), R ⁹ is a hydrogen atom or a methyl group, and R ¹⁰ is an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 20 carbon atoms.)

[9] The polymer emulsion according to [8], wherein in the formula (III), R ² is CH ₂ CH ₂ .

[10] The polymer emulsion according to [8] or [9], wherein an average particle size of the core-shell type polymer particles is 150 nm or less.

[11] The polymer emulsion according to any one of [8] to [10], wherein a main component of the hydrophobic unsaturated monomer is a (meth) acrylic acid ester.

[12] A coating composition for synthetic paper, containing the polymer emulsion according to any one of [1] to [11].

[13] A coating composition having a synthetic paper made of a synthetic resin film or synthetic fiber and a coating film made of the coating composition for synthetic paper according to [12] formed on one or both sides of the synthetic paper paper.

[14] The coated synthetic paper according to [13], wherein the synthetic paper is made of a synthetic resin film.

[15] A method for producing a polymer emulsion according to any one of [1] to [7],
A copolymer having a structural unit (a _p 1) derived from a monomer represented by the following formula (IV) and the structural unit (a2) is prepared, and a nitrogen atom in the copolymer is converted into a cation modifier. Cationization (A) step of obtaining the cationic polymer (A) by cationization with
An emulsion step of emulsifying the cationic polymer (A) and the hydrophobic polymer (B) in an aqueous medium,
A method for producing a polymer emulsion, wherein the cationic modifier contains a monohalogenated quaternary ammonium salt represented by the formula (V).
CH ₂ = C (R ¹ ) COZR ² NR ³ R ⁴ (IV)
(In formula (IV), Z and R ^{1 to} R ⁴ have the same meanings as those of formula (I).)
^{X (R 5 -N + R 6} R 7) n R 8 · nX - ··· (V)
(In the formula (V), X, R ^{5 to} R ⁸ and n have the same meanings as the formula (I).)

[16] A method for producing a polymer emulsion according to any one of [1] to [7],
Polymer (A) polymerization step for obtaining the cationic polymer (A) by copolymerizing the monomer represented by the formula (I) and the monomer represented by the formula (II) When,
A method for producing a polymer emulsion, comprising an emulsion step of emulsifying the cationic polymer (A) and the hydrophobic polymer (B) in an aqueous medium.

[17] The emulsion step includes a step of mixing the cationic polymer (A), an aqueous medium, and a polymerization initiator of the hydrophobic unsaturated monomer to obtain an aqueous phase;
A step of obtaining a pre-emulsion by mixing the cationic polymer (A), the hydrophobic unsaturated monomer and an aqueous medium;
The method for producing a polymer emulsion according to [15] or [16], comprising: a step of polymerizing the hydrophobic unsaturated monomer while dropping the pre-emulsion in the aqueous phase to obtain the polymer emulsion. .

[18] A method for producing a polymer emulsion according to any one of [8] to [11],
And the following formula (IV) represented by the monomeric structural units derived from (c _p 1), to prepare a copolymer having the structural unit (c2), a nitrogen atom a cation modifier in the copolymer Cationization (C) step of obtaining the cationic polymer (C) by cationization with
An emulsion step of emulsifying the cationic polymer (C) and the hydrophobic polymer (B) in an aqueous medium,
A method for producing a polymer emulsion, wherein the cationic modifier contains a monohalogenated acetic acid alkyl ester represented by the formula (VI).
CH ₂ = C (R ¹ ) COZR ² NR ³ R ⁴ (IV)
(In formula (IV), Z and R ^{1 to} R ⁴ have the same meanings as those of formula (III).)
XCH ₂ COOR ⁸ (VI)
(In the formula (VI), X and R ⁸ have the same meanings as the formula (III).)

[19] A method for producing a polymer emulsion according to any one of [8] to [11],
Polymer (C) polymerization step for obtaining the cationic polymer (C) by copolymerizing the monomer represented by the formula (III) and the monomer represented by the formula (II) When,
A method for producing a polymer emulsion, comprising an emulsion step of emulsifying the cationic polymer (C) and the hydrophobic polymer (B) in an aqueous medium.

[20] The emulsion step is a step of mixing the cationic polymer (C), an aqueous medium, and a polymerization initiator of a hydrophobic unsaturated monomer to obtain an aqueous phase;
A step of obtaining a pre-emulsion by mixing the cationic polymer (C), the hydrophobic unsaturated monomer and an aqueous medium;
The method for producing a polymer emulsion according to [18] or [19], comprising: a step of polymerizing the hydrophobic unsaturated monomer while dropping the pre-emulsion in the aqueous phase to obtain the polymer emulsion. .

  According to the polymer emulsion, the coating composition for synthetic paper, and the coated synthetic paper, water resistance can be improved while suppressing a decrease in the antistatic performance of the synthetic paper. Therefore, for example, it is possible to prevent a printing trouble such as a paper feeding trouble or an ink flow during printing. Moreover, according to the said manufacturing method, manufacture of the polymer emulsion which can improve water resistance is possible, suppressing the fall of the anti-static performance of a synthetic paper.

The schematic of the polymer emulsion in an Example. The schematic of the core-shell type polymer in an Example. The coated synthetic paper which has the synthetic paper in an Example, and the coating film formed on the surface.

<Shell part in core-shell type polymer particles>
The shell part in the core-shell type polymer particle is composed of a cationic polymer (A) or a cationic polymer (C) having a cation in the polymer. The above antistatic performance is exhibited by the cations in such a cationic polymer.

  The cationic polymer (A) comprises a structural unit (a1) derived from the monomer represented by the formula (I) and a structural unit (a2) derived from the monomer represented by the formula (II). It has the copolymer which has. In the formula (I), n is 0 to 3, and the structural unit (a1) is a dication, a trication, or a tetracation. In formula (1), n = 1, that is, the structural unit (a1) is preferably a dication. In this case, the antistatic performance and water resistance can be exhibited in a more balanced manner.

In the formula (I), R ² is preferably CH ₂ CH ₂ and R ⁵ is preferably CH ₂ CH (OH) CH ₂ . Also in this case, the anti-electricity performance and water resistance can be exhibited in a more balanced manner.

  In the cationic polymer (A), the content of the structural unit (a1) is preferably 20 to 50% by mass, and the content of the structural unit (a2) is preferably 80 to 50% by mass. In this case, the antistatic property and the water resistance can be improved with a better balance. Furthermore, from the viewpoint of improving both in a balanced manner, the content of the structural unit (a1) is 30 to 70% by mass, and the content of the structural unit (a2) is more preferably 70 to 30% by mass, More preferably, the content of the structural unit (a1) is 35 to 65% by mass, and the content of the structural unit (a2) is 65 to 35% by mass.

In the cationic polymer (A), the copolymer can further contain a structural unit (a3) derived from a monomer represented by the following formula (VII). In this case, by setting the total content of the structural unit (a1) and the structural unit (a3) to, for example, 20 to 50% by mass, the antistatic property and the water resistance can be improved in a balanced manner.
Py ⁺ -C (R ¹¹ ) = CH ₂ · X ⁻ (VII)
(In the formula (VII), Py ⁺ is a pyridyl group having a cationized nitrogen atom N ⁺ , R ¹¹ is a hydrogen atom or a methyl group, and X is a halogen atom)

  The cationic polymer (A) can further contain 20% by mass or less of a structural unit (a4) derived from another vinyl monomer. Examples of such vinyl monomers include styrene, side chain substituted derivatives of styrene, (meth) acrylic acid esters, acrylonitrile, methacrylonitrile, chloroethylenes, maleic acid esters, vinyl ethers, acrolein, alkanes. At least one selected from the group consisting of ril ethers, allyl chloride, butadiene and the like can be used. As the side chain substituted derivative of styrene, vinyl toluene, chlorostyrene, α-methylstyrene, or the like can be used. As (meth) acrylic acid esters, esters in which the alcohol part is an alkyl group having 1 to 18 carbon atoms (excluding a cycloalkyl group) can be used. Specifically, hydroxyethyl methacrylate, tetrahydromethacrylate, or the like can be used. Moreover, vinyl butyl ether, vinyl phenyl ether, etc. can be used as vinyl ethers. As the aryl ether, for example, allyl ethyl ether can be used. In the present specification, “(meth) acrylic acid” represents at least one of “acrylic acid” and “methacrylic acid”.

  The cationic polymer (C) comprises a structural unit (c1) derived from the monomer represented by the formula (III) and a structural unit (c2) derived from the monomer represented by the formula (II). It has the copolymer which has. Formula (III) has a cation, and the structural unit (c1) corresponds to a (mono) cation.

In the formula (III), R ² is preferably CH ₂ CH ₂ . In this case, the antistatic performance and water resistance can be exhibited in a more balanced manner.

  In the cationic polymer (C), the content of the structural unit (c1) is 20 to 50% by mass, and the content of the structural unit (c2) is 80 to 50% by mass. When the content of the structural unit (c1) is less than 20% by mass, the antistatic performance may be insufficient, or the water resistance may be insufficient. On the other hand, when content with a structural unit (c1) exceeds 50 mass%, there exists a possibility that it may become excessively water-soluble. As a result, for example, when the above-mentioned coated synthetic paper is prepared using a polymer emulsion and the coated synthetic paper is used for offset printing, continuous printability is impaired, and in particular, transferability of the printing ink of the second color May get worse. From the viewpoint of improving the antistatic performance and water resistance in a more balanced manner, the content of the structural unit (c1) is 20 to 70% by mass, and the content of the structural unit (c2) is 80 to 30% by mass. More preferably, the content of the structural unit (c1) is 35 to 65% by mass, and the content of the structural unit (c2) is further preferably 65 to 35% by mass.

  Moreover, the cationic polymer (C) contains the structural unit (c3) derived from the monomer represented by the formula (VII), as in the case of the cationic polymer (A). Can do. The total content of the structural unit (c1) and the structural unit (c3) is preferably 20 to 50% by mass for the same reason as the above-mentioned cationic polymer (A).

  Further, the cationic polymer (C) can further contain 20% by mass or less of a structural unit (c4) derived from another vinyl monomer in the same manner as the above-mentioned cationic polymer (A). As such a vinyl-type monomer, the monomer similar to the above-mentioned structural unit (a4) can be used.

<Core part of core / shell type polymer particle>
The core part of the core-shell type polymer particle is composed of a hydrophobic polymer (B), and the hydrophobic polymer (B) has a structural unit (b) derived from a hydrophobic unsaturated monomer. The hydrophobic unsaturated monomer preferably has a hydrocarbon chain having 1 to 45 carbon atoms, more preferably 1 to 24 carbon atoms. The hydrocarbon chain may be either a straight chain or a branched chain. Moreover, the hydrocarbon group which has a monocyclic or polycyclic aliphatic ring or an aromatic ring may be contained. Further, the ring may further contain a hydrocarbon group having a linear or branched alkyl group as a substituent.

  The main component of the hydrophobic unsaturated monomer is preferably a (meth) acrylic acid ester. That is, the hydrophobic polymer (B) is preferably made of a (meth) acrylic resin. In this case, when the coated synthetic paper is produced, the adhesion between the synthetic paper made of a synthetic resin film or the like and the hydrophobic polymer (B) can be enhanced.

<Core-shell type polymer particles>
When the shell portion is composed of the cationic polymer (C), the glass transition temperature Tg _C of the cationic polymer (C) is 40 to 85 ° C., and the glass transition temperature Tg _B of the hydrophobic polymer (B) in the core portion. By making the temperature lower than the glass transition temperature Tg _C of the cationic polymer (C), the water resistance can be improved without lowering the antistatic property. This is because when the above-mentioned synthetic paper coating composition containing a polymer emulsion is applied to, for example, synthetic paper, the hydrophobic polymers (B) in the core portion of the core-shell type polymer particles are fused to each other. This is considered to be because the continuity of the layer made of the hydrophobic polymer (B) is improved. In addition, when Tg _C and Tg _B satisfy the above relationship, the film formability can be improved.

  When the cationic polymer (A) is used, it is not always necessary to control the glass transition temperature of the core part and the shell part as in the above-mentioned cationic polymer (C). That is, by adopting the monomer-derived structural unit (a1) represented by the formula (I) instead of the monomer-derived structural unit (c1) represented by the formula (III), the glass transition temperature Even without adjusting the above, it is possible to improve the water resistance without deteriorating the antistatic property. This is particularly noticeable when the cationic polymer (A) is a dication (that is, when n = 1 in the formula (I)).

Preferably, the glass transition temperature Tg _B of the hydrophobic polymer (B) is lower than the glass transition temperature Tg _{A of the} cationic polymer (A). Preferably, the cationic polymer (A) has a glass transition temperature Tg _A of 40 to 85 ° C. In this case, the water resistance can be further improved without lowering the antistatic property. As in the case of the above-mentioned cationic polymer (C), the hydrophobic polymer (B) in the core part of the core-shell type polymer particle is easily fused to each other, and the hydrophobic polymer (B) This is considered to be because the continuity of the layer is improved. Also in this case, the film formability can be improved.

  The mass ratio of the core part to the shell part [core part / shell part] is preferably 1/10 to 10/1 from the viewpoint of improving the antistatic performance and water resistance at a higher level. In this case, the polymerization of the hydrophobic unsaturated monomer tends to proceed stably during the production of the polymer emulsion described later. Therefore, coarse particles and block-like polymer pieces tend not to be generated during the polymerization, and the storage stability of the polymer emulsion tends to be improved.

  The mass ratio [core portion / shell portion] is more preferably 1/5 to 5/1. By completing the polymerization within this range, it is possible to obtain an emulsion that is effective in homogenizing particles and excellent in storage stability. In this case, the cationic polymer (A) or the cationic polymer (C) becomes a continuous phase when the synthetic paper coating composition containing the polymer emulsion is applied to the synthetic paper. Since the hydrophobic polymer (B) exhibits excellent adhesion to, for example, a synthetic paper made of a resin film while exhibiting an antistatic effect, the water resistance can be further improved.

<Polymer emulsion>
The polymer emulsion has an aqueous medium and core-shell type polymer particles dispersed therein. Examples of the aqueous medium include water, alcohol, and a mixture thereof. The average particle diameter of the core-shell type polymer particles in the aqueous medium is preferably 150 nm or less. In this case, the smoothness and transparency of the coating film obtained by applying the polymer emulsion to an object such as synthetic paper can be improved.

<Method for producing polymer emulsion>
When the shell portion is made of the cationic polymer (A), the cationic polymer (A) can be obtained by performing the following cationization (A) step. That is, a copolymer having a structural unit (a _p 1) derived from the monomer represented by the formula (IV) and a structural unit (a2) derived from the monomer represented by the formula (II) Is prepared, and the nitrogen atom in the copolymer is cationized with a cation modifier (cationization (A) step).

  Specific examples of the monomer represented by the formula (IV) include N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate, N, N-dimethylaminoethyl acrylate, N, N-diethylaminoethyl acrylate. N, N-dimethylaminopropyl methacrylate, N, N-dimethylaminobutyl methacrylate and the like.

  Specific examples of the monomer represented by the formula (II) include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tertiary butyl (meth) acrylate, cyclohexyl Examples thereof include alkyl (meth) acrylates such as (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate and stearyl (meth) acrylate.

In the cationization (A) step, a monohalogenated quaternary ammonium salt represented by the formula (V) is used as a cation modifier. By using this cation modifier, the structural unit (a _p 1) derived from the monomer represented by formula (IV) can be cationized into a dication, a trication, or a tetracation. The amount of the cationic modifier used can be, for example, a theoretically required amount. The amount of the cationic modifier used can be equimolar to the number of moles of the structural unit (a _p 1), but it is not necessarily equimolar. The use amount of the cation modifier is adjusted to, for example, 0.7 to 1.3 mol times, preferably 0.9 to 1.1 mol times with respect to the number of moles of the structural unit (a _p 1). Can do.

  Specific examples of monohalogenated quaternary ammonium salts include glycidyltrimethylammonium chloride, 3-chloro-2-hydroxypropyltrimethylammonium chloride, 3-chloro-2-hydroxypropyltriethanolammonium chloride, glycidyltrimethylammonium chloride, glycidyl. Examples thereof include methylbenzylammonium chloride, glycidyltrimethylammonium chloride, glycidyldimethylbutylammonium chloride and the like. In addition, although chloride was illustrated, other halides may be sufficient.

  The cationic polymer (A) can be obtained by carrying out the above-mentioned cationization (A) step, but can also be obtained by carrying out the polymer (A) polymerization step. That is, the monomer represented by the formula (I) and the monomer represented by the formula (II) are copolymerized (polymer (A) polymerization step). As the monomer represented by the formula (I), a dication, trication, tetracation or the like in which the nitrogen atom in the monomer represented by the above formula (IV) is cationized by a modifier can be used. . The monomer represented by the formula (II) is as described above.

The cationic polymer (C) can be obtained by performing the following cationization (C) step. That is, a copolymer having the structural unit (c _p 1) derived from the monomer represented by the formula (IV) and the structural unit (c2) derived from the monomer represented by the formula (II) Is prepared, and the nitrogen atom in the copolymer is cationized with a cation modifier (cationization (C) step).

In the cationization (C) step, a monohalogenated acetic acid alkyl ester represented by the formula (VI) is used as a cation modifier. By using this cationic modifier, a structural unit derived from a monomer represented by the formula _{(IV) (c p 1)} , it can be cationized. The amount of the cation-modified agents, for example the required amount of theoretical, for example can be the number of moles equimolar structural unit (c _p 1), need not be equimolar. The amount of the cation-modified agent with respect to the number of moles of the structural unit (c _p 1), for example 0.7 to 1.3 mol times, preferably adjusted to the range of 0.9 to 1.1 mol per mol Can do.

Specific examples of the monohalogenated acetic acid alkyl ester include XCH ₂ COOCH ₃ , XCH ₂ COOC ₂ H ₅ , XCH ₂ COOC ₃ H ₈ , XCH ₂ COOC ₄ H _{9 and the} like. X is a halogen atom such as Cl, Br, or I.

  When the shell portion is made of the cationic polymer (C), the cationic polymer (C) can be obtained by performing the following polymer (C) polymerization step. That is, the monomer represented by the formula (IV) and the monomer represented by the formula (III) are copolymerized (polymer (C) polymerization step).

  The cationic polymer (C) can be obtained by performing the above-mentioned cationization (C) step, but can also be obtained by carrying out the following polymer (C) polymerization step. That is, the monomer represented by the formula (III) and the monomer represented by the formula (II) are copolymerized (polymer (C) polymerization step).

  As the monomer represented by the formula (III), a monomer in which the nitrogen atom in the monomer represented by the above formula (IV) is cationized by a modifier can be used. Specifically, for example, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, etc., monohalogenated acetic acid alkyl ester, etc. A monomer obtained by modification with a modifying agent can be used. The monomer represented by the formula (II) is as described above.

  As a polymerization method for obtaining each copolymer, known polymerization methods such as bulk polymerization, solution polymerization, and emulsion polymerization using a radical initiator can be employed. Among these, a preferred polymerization method is a solution polymerization method, and the polymerization is carried out by dissolving each monomer in a solvent, adding a radical polymerization initiator and heating and stirring in a nitrogen stream. The solvent is preferably water, alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, etc., and these solvents may be used in combination. As the polymerization initiator, peroxides such as benzoyl peroxide and lauroyl peroxide, and azo compounds such as azobisisobutyronitrile and azobisvaleronitrile are preferably used. The monomer concentration is usually 10 to 60% by weight, and the concentration of the polymerization initiator is usually 0.1 to 10% by weight with respect to the monomer. The molecular weight of the copolymer can be set to any level depending on the polymerization conditions such as the polymerization temperature, the type and amount of the polymerization initiator, the amount of solvent used, and the chain transfer agent. In general, the molecular weight of the obtained polymer is 1000 to 1000000, but the range of 1000 to 500000 is particularly preferable.

  The polymer emulsion is obtained by emulsifying the cationic polymer (A) or the cationic polymer (C) obtained as described above and the hydrophobic polymer (B) in an aqueous medium (emulsion step). . An emulsion process can be implemented by performing the following 1st-3rd processes, for example.

  As a 1st process, the process which obtains an aqueous phase by mixing a cationic polymer (A) or a cationic polymer (C), an aqueous medium, and the polymerization initiator of a hydrophobic unsaturated monomer is performed. In the first step, a part of the use amount of the cationic polymer (A) or the cationic polymer (C) used for the production of the polymer emulsion is used. Moreover, as a 2nd process, the process of obtaining a pre-emulsion by mixing a cationic polymer (A) or a cationic polymer (C), a hydrophobic unsaturated monomer, and an aqueous medium is performed. In the second step, the remainder of the use amount of the cationic polymer (A) or the cationic polymer (C) can be used. As the third step, a step of obtaining a polymer emulsion by polymerizing the hydrophobic unsaturated monomer while dropping the pre-emulsion in the aqueous phase is performed. Of the first to third steps, the first step and the second step are in no particular order.

  Specific examples of the hydrophobic unsaturated monomer include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, 3-methoxyethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n- Butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, 2-phenylethyl (Meth) acrylate, benzyl (meth) acrylate, tetradecyl (meth) methacrylate, diethylaminoethyl (meth) acrylate, diisopropylaminoethyl (meth) acrylate, and the like. In the present specification, “(meth) acrylate” represents at least one of “acrylate” and “methacrylate”.

  The hydrophobic unsaturated monomer may be copolymerized with a functional group-containing monomer. Examples of the functional group-containing monomer include a monomer having two or more vinyl groups in the molecular structure, a glycidyl group-containing monomer, an allyl group-containing monomer, a hydrolyzable silyl group-containing monomer, Examples include acetoacetyl group-containing monomers, hydroxyl group-containing monomers, and carboxyl group-containing monomers.

  Examples of monomers having two or more vinyl groups in the molecular structure include divinylbenzene, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, ethylene glycol di (meth) acrylate, 1,2-propylene glycol di (Meth) acrylate, 1,3-propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, Examples include trimethylolpropane tri (meth) acrylate and allyl (meth) acrylate.

  Among these, ethylene glycol di (meth) acrylate, 1,2-propylene glycol di (meth) acrylate, 1,3-propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, neopentylglycol di (meth) acrylate or trimethylolpropane tri (meth) acrylate is preferred in terms of good copolymerizability with the (meth) acrylate monomer.

  Examples of the glycidyl group-containing monomer include glycidyl (meth) acrylate, glycidyl (meth) allyl ether, 3,4-epoxycyclohexyl (meth) acrylate, and the like.

  Examples of the allyl group-containing monomer include allyl groups such as triallyloxyethylene, diallyl maleate, triallyl cyanurate, triallyl isocyanurate, tetraallyloxyethane trimethylolpropane diallyl ether, and pentaerythritol triallyl ether. And monomers having two or more, allyl glycidyl ether, and allyl acetate.

  Examples of the hydrolyzable silyl group-containing monomer include vinyl-based silyl group-containing monomers such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, and vinylmethyldimethoxysilane; -(Meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane and γ- (meth) acryloxypropylmethyldiethoxysilane ( And (meth) acryloxy-based silyl group-containing monomers. Among these, a (meth) acryloxy-based silyl group-containing monomer is preferable in that it is excellent in copolymerizability with a hydrophobic unsaturated monomer. In addition, “(meth) acryloxy” in the present specification represents at least one of “acryloxy” and “methacryloxy”.

  Examples of the acetoacetyl group-containing monomer include acetoacetate vinyl ester, acetoacetate allyl ester, diacetoacetate allyl ester, acetoacetoxyethyl (meth) acrylate, acetoacetoxyethyl crotonate, acetoacetoxypropyl (meth) acrylate, Examples include acetoacetoxypropyl crotonate and 2-cyanoacetoacetoxyethyl (meth) acrylate.

  Examples of the hydroxyl group-containing monomer include (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. From the viewpoint of protective colloidal action during polymerization, 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate is preferred.

  Examples of the carboxyl group-containing monomer include (meth) acrylic acid, acrylic acid dimer, crotonic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid, glutaconic acid, itaconic acid, acrylamide N-glycolic acid and Cinnamic acid and the like can be mentioned. Among these, acrylic acid or methacrylic acid is preferable from the viewpoint of protective colloidal action during polymerization.

  The content ratio of the functional group-containing monomer is preferably 10% by weight or less, more preferably 5% by weight or less, based on the entire monomer component. By adjusting the content within this range, the hydrophobic polymer (B) is suppressed from becoming too hard, sufficient adhesive force is exhibited, and water resistance can be further improved when a coating film is formed. . Further, from the viewpoint of exerting a protective colloidal action without reducing water resistance, the content ratio of the functional group-containing monomer to the whole monomer component is preferably 0.01% by weight or more, more preferably Is 0.05% by weight or more, more preferably 0.1% by weight or more.

  Further, when the functional group-containing monomer (c) is a monomer having two or more vinyl groups in the molecular structure, the content of the monomer is 0 with respect to the whole monomer component. It is preferably 0.01 to 5% by weight, more preferably 0.05 to 3% by weight, and still more preferably 0.1 to 1% by weight.

  In addition, within the range not impairing the effects of the present invention, a small amount of styrene monomer such as styrene or α-methylstyrene, vinyl formate, vinyl acetate, vinyl propionate, vinyl valeate, vinyl butyrate, Vinyl ester monomers such as vinyl butyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl versatate or vinyl 2-ethylhexanoate as hydrophobic unsaturated monomers It may be copolymerized.

  Examples of the polymerization initiator include inorganic peroxides such as potassium persulfate, sodium persulfate and ammonium persulfate, organic peroxides, azo initiators, hydrogen peroxide, butyl peroxide, and t-butyl hydroperoxide. And redox polymerization initiators combining these with reducing agents such as acidic sodium sulfite and L-ascorbic acid. These can be used alone or in combination of two or more.

  In the emulsion process, a polymerization regulator, an auxiliary emulsifier, a plasticizer, and the like can be further used.

  As a polymerization regulator, it can select suitably from well-known things. Examples of such a polymerization regulator include a chain transfer agent and a buffer.

  Examples of the chain transfer agent include alcohols such as methanol, ethanol, propanol and butanol, aldehydes such as acetaldehyde, propionaldehyde, n-butyraldehyde, furfural and benzaldehyde, and dodecyl mercaptan, lauryl mercaptan, normal mercaptan, thioglycolic acid And mercaptans such as octyl thioglycolate and thioglycerol. These can be used alone or in combination of two or more. The use of the chain transfer agent is effective in that the polymerization is stably performed, and it is preferably used for adjusting the degree of polymerization of the hydrophobic polymer (B).

  Any auxiliary emulsifier can be used as long as it is known to those skilled in the art as being usable for emulsion polymerization. Accordingly, the auxiliary emulsifier is appropriately selected from known ones such as anionic, cationic and nonionic surfactants, water-soluble polymers having protective colloid ability other than amphoteric polymers, and water-soluble oligomers. can do.

  Examples of the surfactant include anionic surfactants such as sodium lauryl sulfate and sodium dodecylbenzenesulfonate, and nonionic surfactants such as those having a pluronic type structure and those having a polyoxyethylene type structure. Can be mentioned. Among these surfactants, ionic surfactants, particularly anionic surfactants such as sodium stearoylmethyl taurate, sodium stearoyl glutamate, or sodium stearoyl lactate among the anionic surfactants are preferable. Moreover, the reactive surfactant which has a radically polymerizable unsaturated bond in a structure can also be used as a surfactant. These may be used alone or in combination of two or more.

Examples of the anionic emulsifier include “New Coal 560 SF”, “New Coal 562 SF”, “New Coal 707 SF”, “New Coal 707 SN”, “New Coal 714 SF”, “New Coal 723 SF”, “New Coal 740 SF”, “New Call 2308SF”, “New Call 2320SN”, “New Call 1305SN”, “New Call 271A”, “New Call 271NH”, “New Call 210”, “New Call 220”, “New Call RA331”, “New Call "Cole RA332" (trade name, manufactured by Nippon Emulsifier Co., Ltd.); "Latemul B-118E", "Lebenol WZ", "Neoperex G15" (trade name, manufactured by Kao Corporation); "Hitenol N08" (product) Name, Daiichi Kogyo Seiyaku Co., Ltd.) That.
Examples of the nonionic emulsifier include “Nonipol 200” and “New Pole PE-68” (trade names, manufactured by Sanyo Chemical Industries, Ltd.).
Examples of the polymer emulsifier include polyvinyl alcohol, polyhydroxyethyl (meth) acrylate, polyhydroxypropyl (meth) acrylate, and polyvinylpyrrolidone.
Examples of reactive emulsifiers include “Antox MS-60” and “Antox MS-2N” (trade name, manufactured by Nippon Emulsifier Co., Ltd.); “Eleminol JS-2” (trade name, manufactured by Sanyo Chemical Industries, Ltd.) "Latemuru S-120", "Latemuru S-180", "Latemuru S-180A", "Latemuru PD-104" (manufactured by Kao Corporation); "Adekaria Soap SR-10", "Adekaria Soap" “SE-10” (trade name, manufactured by ADEKA Corporation); “Aqualon KH-05”, “Aqualon KH-10”, “Aqualon HS-10” (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) Reactive anionic emulsifiers: “Adekalia Soap NE-10”, “Adekalia Soap ER-10”, “Adekalia Soap NE-20”, “Adekalia Soap ER-20”, “Adekalia Soap NE” “30”, “Adekaria soap ER-30”, “Adekaria soap NE-40”, “Adekaria soap ER-40” (trade name, manufactured by ADEKA Corporation); “Aquaron RN-10”, “Aquaron RN” Reactive nonionic emulsifiers such as “-20”, “AQUALON RN-30”, “AQUALON RN-50” (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).
These emulsifiers may be used individually by 1 type, and may use 2 or more types together.

  The use of the surfactant has the effect of allowing the emulsion polymerization to proceed smoothly and facilitating control (effect as an emulsifier) or suppressing the generation of coarse particles and block-like substances generated during the polymerization. However, if many of these surfactants are used as emulsifiers, the shell may be separated from the core. For this reason, when using a surfactant, the amount used should be an auxiliary amount with respect to the cationic polymer (A) or the cationic polymer (C), that is, as small as possible. preferable.

<Coating composition for synthetic paper>
The coating composition for synthetic paper contains a polymer emulsion. The composition for coating synthetic paper can further contain various additives, colorants and the like. Specifically, pigments such as titanium oxide, zinc white, and carbon black, disperse dyes, acid dyes, cationic dyes, reactive dyes, antioxidants, lubricants, colorants, and stabilizers, as long as the properties are not impaired. Agent, wetting agent, thickener, foaming agent, antifoaming agent, coagulant, gelling agent, anti-settling agent, anti-aging agent, softening agent, plasticizer, leveling agent, anti-waxing agent, pigment dispersant, An ultraviolet absorber, a weathering agent, a flame retardant, etc. can be added. These types are not particularly limited.

<Coated synthetic paper>
The coated synthetic paper has a synthetic paper and a coating film formed on the surface thereof. A coating film consists of a coating composition for synthetic paper. The coating film may be formed on one side of the synthetic paper or on both sides. In the coating film, the cationic polymer (A) or the cationic polymer (C) exhibits an antistatic effect by becoming a sea layer having a sea-island structure, and the cationic polymer (A) and the hydrophobic polymer (B). Alternatively, by employing a combination of the cationic polymer (C) and the hydrophobic polymer (B), the film forming property can be improved. Furthermore, it becomes possible to cause fusion between the core particles. As a result, the continuity of the hydrophobic resin layer composed of the core layer is improved, and the water resistance of the coating film can be increased. Further, the hydrophobic polymer (B) contributes to prevention of ink bleeding and transfer. Therefore, if there is little hydrophobic polymer (B), there exists a possibility that this prevention effect may fall.

  Examples of synthetic paper include synthetic resin film and synthetic pulp paper. As a synthetic resin film, a film of a thermoplastic resin such as polyolefin, polyethylene terephthalate, polybutylene terephthalate, polystyrene, nylon-6, or a film layer formed of a thermoplastic resin and an inorganic fine powder or an organic filler is provided on the surface. The thing which has can be mentioned. Examples of polyolefin include polypropylene, polyethylene, and propylene / ethylene copolymer. Synthetic pulp paper is a synthetic paper made of synthetic fibers, and is made with a paper machine using a resin fiber made from synthetic resin as a raw material (that is, synthetic fiber) as a substitute for pulp and adding a binder. Can be mentioned.

  The synthetic paper is preferably made of a synthetic resin film. More preferably, it is a biaxially stretched synthetic resin film containing a fine filler. Synthetic paper made of a synthetic resin film can be obtained by forming a coating film as described above, for example, because it is difficult to obtain sufficient antistatic performance even if an antistatic agent or the like is added to the film. The above effects can be fully enjoyed.

Example 1
The polymer emulsion of Example 1 will be described with reference to the drawings. As illustrated in FIGS. 1 and 2, the polymer emulsion 1 of this example is a core-shell type polymer in which the shell portion 21 is made of a cationic polymer (A) and the core portion 22 is made of a hydrophobic polymer (B). The particles 2 are dispersed in the aqueous medium 10. Hereinafter, the polymer emulsion of this example will be described in detail.

(1) Production of Cationic Polymer (A) Cationic polymer (A) was produced as follows. First, a four-necked flask equipped with a reflux condenser, a thermometer, a glass tube for nitrogen substitution, and a stirring device is represented by the structural formula CH ₂ ═C (CH ₃ ) COOCH ₂ CH ₂ N (CH ₃ ) _2. Dimethylaminoethyl methacrylate (ie, DMMA): 35 parts by mass, EMA: 20 parts by mass, CHMA: 20 parts by mass, SMA: 25 parts by mass, ethyl alcohol 150 parts by mass, and azobisisobutyronitrile 1 part by mass The polymerization reaction was carried out for 6 hours at a temperature of 80 ° C. under a nitrogen stream.

Next, in the flask, 60% by mass of the modifying agent Cl—CH ₂ CH (OH) CH ₂ N ⁺ (CH ₃ ) ₃ .Cl ⁻ (ie, 3-chloro-2-hydroxypropyltrimethylammonium chloride). 70 parts by mass of an aqueous solution was added, and further reacted at a temperature of 80 ° C. for 15 hours. Then, ethyl alcohol was distilled off while dropping water into the flask to obtain an aqueous solution of 20% by mass of cationic polymer A as the final solid content. In addition, 1.2 mass parts of modifier | denaturants were used with respect to 1 mass part of DMMA. With this modifier, all of the structural units derived from DMMA in the copolymer were modified, and each structural unit derived from DMMA in the copolymer after modification became a dication. The glass transition temperature Tg _A of the cationic polymer A of this example is 53 ° C.

(2) Production of polymer emulsion As the hydrophobic unsaturated monomer constituting the hydrophobic polymer (B) in the core, methyl methacrylate (ie, MMA), butyl acrylate (ie, BA), and stearyl methacrylate (ie, SMA) ) Was prepared. These hydrophobic unsaturated monomers were separated from the 20% by mass aqueous solution of the cationic polymer A prepared as described above so that the core / shell ratio was 2/3 in terms of mass ratio. The core / shell ratio is a mass ratio based on the solid content. The mass ratio of MMA, BA, and SMA is MMA: BA: SMA = 16: 16: 8.

  Half of the aqueous cationic polymer solution separated as described above is placed in a reflux condenser, a dropping pump, a thermometer, a nitrogen gas inlet tube, and a reactor equipped with a stirrer, and the flask is purged with nitrogen. The mixture was stirred at a temperature of 60 ° C. Next, 1% by mass of a polymerization initiator (specifically, t-butyl hydroperoxide) is added to the flask in the total amount of the above-mentioned hydrophobic unsaturated monomers, and the mixture is stirred for 1 minute. 50 mass% ascorbic acid was further added with respect to the dosage. An aqueous phase was thus obtained.

  On the other hand, the remaining half of the cationic polymer aqueous solution, the hydrophobic unsaturated monomer separated as described above, and water were mixed and pre-emulsified with a homomixer. The obtained pre-emulsion was dropped into the flask containing the above-mentioned aqueous phase over 1.5 hours. Thereafter, the temperature was raised to 65 ° C. and the mixture was stirred for 3 hours, and then the reaction was terminated to obtain a 20% by mass polymer emulsion aqueous solution.

The polymer emulsion 1 of this example has a core-shell type polymer particle 2 having a core part 22 made of a hydrophobic polymer (B) and a shell part 21 made of a cationic polymer (A) covering the core part 22. It was dispersed in water 10 (see FIGS. 1 and 2). The core portion 22 is made of a copolymer of a hydrophobic unsaturated monomer described above, the glass transition temperature Tg _B is 15.4 ° C..

  In this example, the monomer constituting the cationic polymer (A) in the shell part, the type of modifier, its blending ratio, the type of monomer constituting the hydrophobic polymer (B) in the core part, its blending ratio Is shown in Table 1 below. The mass ratio (core / shell) between the shell part and the core part is shown in Table 1 described later. The viscosity of the polymer emulsion at 25 ° C. was 12 mPa · s.

  Next, the average particle diameter of the core-shell type polymer particles in the aqueous polymer emulsion was measured. The results are shown in Table 1 below. The average particle diameter is a particle diameter at a volume integrated value of 50% in the particle size distribution obtained by the laser diffraction / scattering method, and was measured using a laser diffraction particle size distribution measuring apparatus (Nanotrac 150 manufactured by Nikkiso Co., Ltd.).

Further, the glass transition temperature Tg _B (° C.) of the hydrophobic polymer B (acrylic resin) forming the core portion of the core-shell type polymer particle was calculated. Tg _B of the polymer in the core part is a theoretical calculation value obtained by the FOX formula shown in the following formula (α). In the formula (α), Tg _B is the glass transition temperature of the polymer forming the core part, W ₁ , W ₂ ,..., W _n are the weight fractions of the respective monomers constituting the polymer, _{Tg 1, Tg 2, ···,} Tg n is the glass transition temperature of the homopolymer of each monomer. A known literature value can be adopted as the glass transition temperature of the homopolymer. Specifically, these glass transition temperatures are, for example, the acrylic ester catalog (1997 edition) of Mitsubishi Rayon Co., Ltd., Kyozo Kitaoka, “Parent Polymer Library 7 Introduction to Synthetic Resins for Paints”, Polymer Publications. Society, p168-p169 etc.
1 / Tg _B = W ₁ / Tg ₁ + W ₂ / Tg ₂ +... + W _n / Tg _n (α)

Further, the glass transition temperature Tg _A (° C.) of the cationic polymer A forming the shell part of the core-shell type polymer particle was calculated as follows. The calculation formula is the same as the calculation method of the hydrophobic polymer (B). When the glass transition point of the cationized structural unit (a1) represented by the above formula (IV) is unknown, the value of dimethylaminoethylmethyl chloride methacrylate was substituted for calculation.

  Next, a coated synthetic paper for evaluation was prepared using the polymer emulsion of this example. As illustrated in FIG. 3, the coated synthetic paper 3 includes a synthetic paper 31 and a coating film 32 formed on at least one surface thereof. The coating film 32 is made of a synthetic paper coating composition containing a polymer emulsion. The synthetic paper 31 in this example is made of a polyethylene terephthalate (PET) film. The coating composition for synthetic paper is a solution having a resin solid content of 20% by mass.

  The coated synthetic paper 3 for evaluation was manufactured as follows. First, a PET film (“O321E100 (CE SE98-F)” manufactured by Mitsubishi Plastics, Inc.) having a thickness of 100 μm was prepared as the synthetic paper 31. Next, a coating composition for synthesis was applied onto the synthetic paper 31 using a bar coater, and dried at a temperature of 100 ° C. for 2 minutes. The coating amount was adjusted so that the film thickness of the coating film 32 after drying was 20 ± 5 μm. Thus, the coating film 32 was formed on the synthetic paper 31, and the coating synthetic paper 3 was obtained.

  Using the coated synthetic paper for evaluation obtained as described above, the following “coating appearance”, “adhesion”, “anti-electricity resistance”, “anti-electricity resistance after water immersion test”, “water immersion” Evaluation of “weight reduction rate after test” was performed.

"Appearance of coating film"
The coating film appearance of the coated synthetic paper was visually determined. A case where the PET film (that is, synthetic paper) was whitened was judged as “bad”, and a case where the film was transparent was judged as “good”. The results are shown in Table 1.

"Adhesion"
Using a cutter, the coating synthetic paper film was scratched with an X mark. The angle formed by the two lines intersected by the X mark is 90 °. Next, after the adhesive tape was attached to the scratched part on the coating film, the adhesive tape was peeled off from the coating film. At this time, the case where the coating film transferred from the PET film (that is, synthetic paper) to the adhesive tape was judged as “bad”, and the case where the coating film remained on the PET film was judged as “good”. The results are shown in Table 1.

"Anti-electricity resistance"
Using a surface resistance measuring device, the surface resistivity of the coated synthetic paper coating film was measured by a method based on JIS K 6271-1-2015. When the surface resistivity exceeded 1 × 10 ¹¹ Ω / □, it was determined as “defective”, and when the surface resistivity was 1 × 10 ¹¹ Ω / □ or less, it was determined as “good”. The results are shown in Table 1.

"Anti-electricity resistance after immersion test"
A water immersion test was conducted in which the coated synthetic paper was left for 24 hours in a state where it was immersed in hot water at a temperature of 40 ° C., and then the coated synthetic paper was removed from the hot water and dried. After this water immersion test, the surface resistivity was measured by the method described above. When the surface resistivity of the paint film after the water immersion test exceeds 1 × 10 ¹¹ Ω / □, it is judged as “bad”, and when the surface resistivity is 1 × 10 ¹¹ Ω / □ or less, it is judged as “good”. Judged. The results are shown in Table 1.

"Weight change after immersion test"
Weight W _P of coating synthetic paper before water immersion, the weight W _A of the coating synthetic paper after water immersion was determined to calculate the weight loss W _E [%] according to the following equation (beta). The results are shown in Table 1.
W _E = 100 × (W _P −W _A ) / W _P (β)

(Examples 2 to 4)
Examples 2 to 4 are examples in which the composition of the hydrophobic polymer (B) and the blending ratio of the cationic polymer (A) and the hydrophobic polymer (B) were changed from those in Example 1. Specifically, Example 1 and Example 1 except that the blending of each monomer was changed so that the cationic polymer (A) and the hydrophobic polymer (B) consist of structural units shown in Table 1 described later. Similarly, a polymer emulsion was prepared, and a coated synthetic paper was prepared using the polymer emulsion. Also in Examples 2 to 4, Table 1 shows the glass transition temperature Tg _B of the core part and the glass transition temperature Tg _A of the shell part. Further, in the same manner as in Example 1, evaluation of “appearance of coating film”, “adhesion”, “anti-electricity resistance”, “anti-electricity resistance after water immersion test”, and “weight reduction rate after water immersion test” were performed. . The results are shown in Table 1.

(Comparative Example 1)
In this example, not a core-shell type polymer particle but a cationic polymer is used alone. Specifically, a coated synthetic paper was produced using the cationic polymer (A) in the same manner as in Example 1. Then, evaluation of “appearance of coating film”, “adhesion”, “anti-electricity resistance”, “anti-electricity resistance after water immersion test”, and “weight reduction rate after water immersion test” were performed in the same manner as in Example 1. . The results are shown in Table 1.

  As can be seen from Table 1, in Examples 1 to 4, the surface resistivity was sufficiently low both before and after the hydrophilic test, and the antistatic property was excellent. Further, it can be seen that the rate of weight reduction after the water immersion test is small, and the coating film is excellent in water resistance. On the other hand, in Comparative Example 1, although the antistatic property was excellent, the weight reduction rate after the water immersion test was large, and the water resistance of the coating film was insufficient. Moreover, in Examples 1-4, the outstanding surface appearance and adhesiveness which are inferior compared with the comparative example 1 were confirmed.

  Therefore, by using a polymer emulsion in which core-shell type polymer particles having a shell part made of a cationic polymer (A) having a specific structure and a core part made of a hydrophobic polymer (B) are dispersed in water, Water resistance can be improved while suppressing a decrease in anti-electric performance. The coated synthetic paper using such a polymer emulsion can prevent the trouble that the ink printed on the label flows or oozes even when this is used as a label or the like. Moreover, since the cationic polymer (A) is contained in the shell part of the core-shell type polymer particle, the coated synthetic paper can improve water resistance while maintaining good ink adhesion.

  As mentioned above, although the Example was described, this invention is not limited to each said Example, In the range which does not deviate from the summary, it is possible to apply to various embodiment.

DESCRIPTION OF SYMBOLS 1 Polymer emulsion 10 Aqueous medium 2 Cationic polymer particle 21 Shell part 22 Core part 3 Coated synthetic paper 31 Synthetic paper 32 Coating film

Claims (20)

A polymer emulsion in which core-shell type polymer particles having a shell part made of a cationic polymer (A) and a core part made of a hydrophobic polymer (B) are dispersed in an aqueous medium,
The cationic polymer (A) includes a monomer-derived structural unit (a1) represented by the following formula (I), and a monomer-derived structural unit (a2) represented by the following formula (II): Comprising a copolymer having
The hydrophobic polymer (B) is a polymer emulsion having a structural unit (b) derived from a hydrophobic unsaturated monomer.
^{_{CH 2 = C (R 1)}} COZR 2 N + R 3 R 4 (R 5 N + R 6 R 7) n -R 8 · (n + 1) X - ··· (I)
(In the formula (I), R ¹ is a hydrogen atom or a methyl group, Z is —O— or —NH—, and R ² and R ⁵ are each independently an alkylene group having 1 to 6 carbon atoms. R ³ , R ⁴ , R ⁶ and R ⁷ are each independently a methyl group or an ethyl group, and R ⁸ is an alkyl group having 1 to 10 carbon atoms or a group having 7 to 10 carbon atoms. An aralkyl group, X is a halogen atom, and n is an integer of 0 to 3.)
CH ₂ = C (R ⁹ ) COOR ¹⁰ (II)
(In Formula (II), R ⁹ is a hydrogen atom or a methyl group, and R ¹⁰ is an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 20 carbon atoms.)   The polymer emulsion according to claim 1, wherein in the formula (1), n = 1. The polymer emulsion according to claim 1 or 2, wherein, in the formula (I), R ² is CH ₂ CH ₂ and R ⁵ is CH ₂ CH (OH) CH ₂ .   The content of the structural unit (a1) in the copolymer is 20 to 50% by mass, and the content of the structural unit (a2) is 80 to 50% by mass. The polymer emulsion according to item. The polymer emulsion according to any one of claims 1 to 4, wherein the glass transition temperature Tg _B of the hydrophobic polymer (B) is lower than the glass transition temperature Tg _A of the cationic polymer (A).   The polymer emulsion according to any one of claims 1 to 5, wherein an average particle size of the core-shell type polymer particles is 150 nm or less.   The polymer emulsion according to any one of claims 1 to 6, wherein a main component of the hydrophobic unsaturated monomer is a (meth) acrylic acid ester. A polymer emulsion in which core-shell type polymer particles having a shell part made of a cationic polymer (C) and a core part made of a hydrophobic polymer (B) are dispersed in an aqueous medium,
The cationic polymer (C) includes a monomer-derived structural unit (c1) represented by the following formula (III), and a monomer-derived structural unit (c2) represented by the following formula (II). Comprising a copolymer having
The content of the structural unit (c1) in the copolymer is 20 to 50% by mass, the content of the structural unit (c2) is 80 to 50% by mass,
The cationic polymer (C) has a glass transition temperature Tg _C of 40 to 85 ° C.,
The hydrophobic polymer (B) has a structural unit (b) derived from a hydrophobic unsaturated monomer,
A polymer emulsion in which the glass transition temperature Tg _B of the hydrophobic polymer (B) is lower than the glass transition temperature Tg _{C of the} cationic polymer (C).
^{_{CH 2 = C (R 1)}} COZR 2 N + R 3 R 4 -CH 2 COOR 8 · X - ··· (III)
(In the formula (III), R ¹ is a hydrogen atom or a methyl group, Z is —O— or —NH—, and R ² is an alkylene group having 1 to 6 carbon atoms and containing a hydroxyl group. R ³ and R ⁴ are each independently a methyl group or an ethyl group, R ⁸ is an alkyl group having 1 to 10 carbon atoms or an aralkyl group having 7 to 10 carbon atoms, and X is a halogen atom. )
CH ₂ = C (R ⁹ ) COOR ¹⁰ (II)
(In the formula (II), R ⁹ is a hydrogen atom or a methyl group, and R ¹⁰ is an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 20 carbon atoms.) The polymer emulsion according to claim 8, wherein in the formula (III), R ² is CH ₂ CH ₂ .   The polymer emulsion according to claim 8 or 9, wherein an average particle size of the core-shell type polymer particles is 150 nm or less.   The polymer emulsion according to any one of claims 8 to 10, wherein a main component of the hydrophobic unsaturated monomer is a (meth) acrylic acid ester.   The coating composition for synthetic paper containing the polymer emulsion of any one of Claims 1-11.   A coated synthetic paper having a synthetic paper made of a synthetic resin film or synthetic fiber and a coating film made of the coating composition for synthetic paper according to claim 12 formed on one or both sides of the synthetic paper.   The coated synthetic paper according to claim 13, wherein the synthetic paper is made of a synthetic resin film. A method for producing a polymer emulsion according to any one of claims 1 to 7,
A copolymer having a structural unit (a _p 1) derived from a monomer represented by the following formula (IV) and the structural unit (a2) is prepared, and a nitrogen atom in the copolymer is converted into a cation modifier. Cationization (A) step of obtaining the cationic polymer (A) by cationization with
An emulsion step of emulsifying the cationic polymer (A) and the hydrophobic polymer (B) in an aqueous medium,
A method for producing a polymer emulsion, wherein the cationic modifier contains a monohalogenated quaternary ammonium salt represented by the formula (V).
CH ₂ = C (R ¹ ) COZR ² NR ³ R ⁴ (IV)
(In formula (IV), Z and R ^{1 to} R ⁴ have the same meanings as those of formula (I).)
^{X (R 5 -N + R 6} R 7) n R 8 · nX - ··· (V)
(In the formula (V), X, R ^{5 to} R ⁸ and n have the same meanings as the formula (I).) A method for producing a polymer emulsion according to any one of claims 1 to 7,
Polymer (A) polymerization step for obtaining the cationic polymer (A) by copolymerizing the monomer represented by the formula (I) and the monomer represented by the formula (II) When,
A method for producing a polymer emulsion, comprising an emulsion step of emulsifying the cationic polymer (A) and the hydrophobic polymer (B) in an aqueous medium. The emulsion step is a step of mixing the cationic polymer (A), an aqueous medium and a polymerization initiator of the hydrophobic unsaturated monomer to obtain an aqueous phase;
A step of obtaining a pre-emulsion by mixing the cationic polymer (A), the hydrophobic unsaturated monomer and an aqueous medium;
The method for producing a polymer emulsion according to claim 15, further comprising polymerizing the hydrophobic unsaturated monomer while dropping the pre-emulsion in the aqueous phase to obtain the polymer emulsion. A method for producing a polymer emulsion according to any one of claims 8 to 11,
And the following formula (IV) represented by the monomeric structural units derived from (c _p 1), to prepare a copolymer having the structural unit (c2), a nitrogen atom a cation modifier in the copolymer Cationization (C) step of obtaining the cationic polymer (C) by cationization with
An emulsion step of emulsifying the cationic polymer (C) and the hydrophobic polymer (B) in an aqueous medium,
A method for producing a polymer emulsion, wherein the cationic modifier contains a monohalogenated acetic acid alkyl ester represented by the formula (VI).
CH ₂ = C (R ¹ ) COZR ² NR ³ R ⁴ (IV)
(In formula (IV), Z and R ^{1 to} R ⁴ have the same meanings as those of formula (III).)
XCH ₂ COOR ⁸ (VI)
(In the formula (VI), X and R ⁸ have the same meanings as the formula (III).) A method for producing a polymer emulsion according to any one of claims 8 to 11,
Polymer (C) polymerization step for obtaining the cationic polymer (C) by copolymerizing the monomer represented by the formula (III) and the monomer represented by the formula (II) When,
A method for producing a polymer emulsion, comprising an emulsion step of emulsifying the cationic polymer (C) and the hydrophobic polymer (B) in an aqueous medium. The emulsion step is a step of mixing the cationic polymer (C), an aqueous medium, and a polymerization initiator of a hydrophobic unsaturated monomer to obtain an aqueous phase;
A step of obtaining a pre-emulsion by mixing the cationic polymer (C), the hydrophobic unsaturated monomer and an aqueous medium;
The method for producing a polymer emulsion according to claim 18, further comprising: polymerizing the hydrophobic unsaturated monomer while dropping the pre-emulsion in the aqueous phase to obtain the polymer emulsion.

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