JP6181544B2 - Method for producing polymer dispersion - Google Patents

Description

  The present invention relates to a method for producing a polymer dispersion having a step of removing volatile impurities such as unreacted monomers from the polymer dispersion.

  As a method for removing impurities such as unreacted monomers from the polymer dispersion after completion of the polymerization, steam stripping, concentration operation, so-called simple distillation or the like is performed.

  For example, Patent Document 1 discloses that an aqueous slurry of vinyl polymer particles is distilled in the presence of a suspension dispersant and a nonionic surfactant or polypropylene glycol having an HLB value of 1 to 10 or a derivative thereof. Therefore, it is disclosed that residual monomer is reduced by preventing foaming and bumping during distillation and stabilizing the distillation operation.

  Further, in Patent Document 2, when removing a porous agent from an aqueous suspension containing porous resin particles, sodium lauryl sulfate and / or sodium dodecylbenzenesulfonate is added to water in the aqueous suspension. It is adjusted to 0.05 wt% to 3 wt%, and this aqueous suspension is continuously or intermittently charged into the still to suppress bumping and efficiently recover the porogen. It is disclosed.

  Patent Document 3 discloses that the monomer can be efficiently removed from the polymer by adding an electrolyte such as an acid or salt to the latex, aggregating the polymer particles, and performing distillation. .

Japanese Examined Patent Publication No. 4-55203 JP 2003-286212 A Japanese Patent Publication No.62-29443

  This invention makes it a subject to provide the manufacturing method of a polymer dispersion liquid which can remove an unreacted monomer efficiently with a small amount of distilled water in a heating stripping process.

That is, the present invention relates to the following method for producing a polymer dispersion.
Polymer dispersion containing (meth) acrylic acid ester monomer (a1) having 1 to 16 carbon atoms and water, and cationic surfactant (d1) and nonionic surfactant having HLB of 11 or more The manufacturing method of a polymer dispersion which has the process of mixing with 1 or more types of surfactant (D) chosen from (d2), and performing heat stripping.

  According to the present invention, in the heating stripping process for removing impurities such as unreacted monomers present in the polymer dispersion, particularly polymer particles, the amount of unreacted monomer can be efficiently removed with a smaller amount of distilled water than before. The manufacturing method which can remove a body can be provided.

The method for producing a polymer dispersion of the present invention includes a polymer dispersion containing a (meth) acrylic acid ester monomer (a1) having an alkyl group having 1 to 16 carbon atoms and water, and a cationic surfactant (d1). And one or more surfactants (D) selected from nonionic surfactants (d2) having an HLB of 11 or more, and a step of performing heat stripping.
In this way, the polymer dispersion is mixed with the cationic surfactant (d1) and one or more surfactants (D) selected from the nonionic surfactants (d2) having an HLB of 11 or more, and heated. When ripping is performed, the monomer (a1) can be efficiently removed.

The reason is not clear, but it is thought as follows.
When the surfactant (D) is present in the polymer dispersion, the (meth) acrylic acid ester monomer (a1) in the polymer particles as the dispersed phase diffuses into the aqueous phase as the continuous phase. It is considered that the monomer (a1) can be removed at a high concentration together with water as a solvent by stripping.

[Polymer dispersion]
The polymer dispersion is, for example, various polymerization modes such as emulsion polymerization, suspension polymerization, and dispersion polymerization of a monomer containing a (meth) acrylic acid ester monomer (a1) having at least an alkyl group having 1 to 16 carbon atoms. The polymer (A) is a dispersion obtained by the production of C, and more preferably, in a liquid containing a cationized starch (B), a nonionic surfactant (C), and water. It is a dispersion of a polymer (A) obtained by emulsion polymerization using a (meth) acrylic acid ester monomer (a1) having an alkyl group and a monomer (a2) of an ethylenically unsaturated carboxylic acid or a salt thereof. .
The (meth) acrylic acid ester monomer (a1) having an alkyl group having 1 to 16 carbon atoms remains, for example, when a polymer dispersion is produced, and usually 10 to 2 in the polymer dispersion. The concentration is 1,000 ppm by mass.

  The median diameter of the polymer dispersion varies depending on the polymerization mode. For example, in the case of emulsion polymerization, 0.01 to 10 μm, in the case of suspension polymerization, 1 to 1000 μm, and in the case of dispersion polymerization, 0.1 μm. The particle size is 10 μm.

  Examples of the water used for the polymer dispersion include distilled water, deionized water, and ultrapure water. Moreover, you may add the organic solvent compatible with water in the range which does not destroy the emulsion state at the time of emulsion polymerization. Examples of the organic solvent include alcohols having 2 or 3 carbon atoms such as methanol, ethanol and isopropyl alcohol, and ketones having 3 or 4 carbon atoms such as acetone and methyl ethyl ketone.

The polymer dispersion is preferably produced by the following steps (1) and (2) from the viewpoint of the usefulness of the resulting polymer dispersion.
Step (1): Step of preparing a solution by adding cationized starch (B) and nonionic surfactant (C) to an aqueous solvent Step (2): Carbon in the solution obtained in Step (1) (Meth) acrylic acid ester (a1) having an alkyl group of 1 to 16 (hereinafter also simply referred to as “monomer (a1)”), and ethylenically unsaturated carboxylic acid or salt thereof (a2) ( Hereinafter, the process of simply performing emulsion polymerization by adding a monomer (a2)) and a polymerization initiator

<Step (1)>
Step (1) is a step of preparing a solution by adding the cationized starch (B) and the nonionic surfactant (C) to an aqueous solvent.
[Cationized starch (B)]
In the polymer dispersion, by adding the cationized starch (B), a hydrophilic colloid is formed so that the cationized starch (B) wraps the polymer particles obtained in the step (2). It is believed that the stability of the resulting polymer dispersion increases. Here, the stability means that a monodispersion is obtained in emulsion polymerization and the polymerization stability means a property of few aggregates, and the resulting polymer dispersion causes phase separation, water separation, particle size change, and the like. Means no stability over time.

The method of introducing a cationic group into the starch to obtain a cationized starch is not particularly limited, and examples thereof include a method of reacting starch with a quaternary ammonium alkylating reagent.
Examples of the quaternary ammonium alkylating reagent include a quaternary ammonium compound having a glycidyl group described in JP 2010-180320 A. From the viewpoint of availability of the compound, glycidyl trimethyl ammonium chloride may be used. preferable.
Specific methods for producing the quaternary ammonium alkylating reagent include, for example, JP-A-56-36501, JP-A-6-100603, JP-A-2010-180320, and JP-A-8-198901. The method of description is mentioned.
A cationized starch may be used independently and may be used in combination of 2 or more type.

  The amount of the cationized starch (B) used is preferably 2 parts by mass or more from the viewpoint of polymerization stability and stability over time with respect to 100 parts by mass of the total amount of monomers used in the step (2) described later. More preferably 4 parts by mass or more, still more preferably 6 parts by mass or more, and preferably 20 parts by mass or less, more preferably 15 parts by mass or less from the viewpoint of the viscosity and polymerization stability of the resulting polymer dispersion. More preferably, it is 10 parts by mass or less.

[Nonionic surfactant (C)]
The nonionic surfactant used in the present invention is a nonionic surfactant (c1) having an HLB of 10 to 13.3 and a nonionic surfactant having an HLB of more than 13.3, from the viewpoint of the stability of the resulting polymer dispersion. It is preferable that surfactant (c2) is included.
The HLB of the nonionic surfactant (c1) is preferably 10 or more, more preferably 11 or more, and still more preferably 12 or more, from the viewpoints of polymerization stability and stability when the resulting polymer dispersion is diluted. Moreover, from the viewpoint of stability at the time of dilution of the obtained polymer dispersion, it is preferably 13.3 or less, more preferably 13 or less, and further preferably 12.5 or less. In addition, in this specification, HLB (hydrophilicity-lipophilic balance) is calculated by the method described in the examples.

The nonionic surfactant (c1) is not particularly limited as long as it has the above HLB, but is preferably a polyoxyalkylene alkyl ether represented by the following general formula (1).
R ¹ —O— (X) _n —H (1)
In Formula (1), R ¹ represents a linear or branched, saturated or unsaturated hydrocarbon group having 8 to 18 carbon atoms, and X is at least one selected from ethylene oxide units and propylene oxide units. Indicates. n represents the number average added mole number of X and is a number of 1 or more and 15 or less.
The carbon number of R ¹ is preferably 8 or more, more preferably 11 or more from the viewpoint of emulsification performance, and preferably 18 or less, more preferably 15 or less from the same viewpoint. R ¹ is preferably a branched chain from the viewpoint of the stabilizing effect of the polymer dispersion when diluted with tap water.

From the viewpoint of emulsifying performance as an emulsifier, R ¹ is preferably a saturated hydrocarbon group.
From the viewpoint of emulsifying performance as an emulsifier, X is preferably an ethylene oxide unit.
n is preferably 1 or more, more preferably 3 or more, still more preferably 6 or more, still more preferably 7 or more, from the viewpoint of polymerization stability and stability when the resulting polymer dispersion is diluted. Is 15 or less, more preferably 13 or less, still more preferably 12 or less, still more preferably 10 or less.

The HLB of the nonionic surfactant (c2) exceeds 13.3 and is preferably 14 or more from the viewpoint of polymerization stability, and is preferably 20 or less and more preferably 19 or less from the same viewpoint.
Although nonionic surfactant (c2) will not be specifically limited if it has said HLB, From a viewpoint of superposition | polymerization stability, the polyoxyalkylene alkyl ether represented by following General formula (2) is preferable.
R ² —O— (Y) _m —H (2)
In formula (2), R ² is a linear or branched, saturated or unsaturated hydrocarbon group having 8 to 18 carbon atoms, and Y represents at least one selected from ethylene oxide units and propylene oxide units. . m shows the number addition mole number of Y, and is a number of 8 or more and 100 or less.
The number of carbon atoms of R ² is preferably 8 or more, more preferably 10 or more, from the viewpoint of improving polymerization stability, and from the same viewpoint, it is preferably 18 or less, more preferably 14 or less.
R ² is preferably linear from the viewpoint of enhancing polymerization stability.
Y is preferably an ethylene oxide unit from the viewpoint of enhancing polymerization stability.
m is preferably 8 or more, more preferably 10 or more, still more preferably 30 or more, still more preferably 40 or more, from the viewpoint of improving polymerization stability, and from the same viewpoint, preferably 100 or less, more preferably Is 70 or less, more preferably 60 or less.

As a nonionic surfactant (c2), from the viewpoint of enhancing polymerization stability, a nonionic surfactant (c2-1) having an HLB of more than 13.3 and an HLB of more than 17 and a nonionic surfactant having an HLB of more than 17 It is preferable that an agent (c2-2) is included.
The HLB of the nonionic surfactant (c2-1) is preferably more than 13.3, more preferably 14 or more from the viewpoint of polymerization stability, and preferably 17 or less, more preferably from the same viewpoint. Is 16 or less.
The HLB of the nonionic surfactant (c2-2) is preferably more than 17, more preferably 18 or more from the viewpoint of polymerization stability, and preferably 20 or less, more preferably 19 from the same viewpoint. It is as follows.
The mass ratio [(c2-1) / (c2-2)] of the nonionic surfactant (c2-1) and the nonionic surfactant (c2-2) added to the aqueous solvent in the step (1) is From the viewpoint of polymerization stability, it is preferably 1 or more, more preferably 5 or more, still more preferably 8 or more, and from the same viewpoint, preferably 50 or less, more preferably 20 or less, still more preferably 10 or less. It is.

  The total addition amount of the surfactant (C) is preferably 1 part by mass or more, more preferably 100 parts by mass with respect to the total use amount of the monomers used in the step (2), from the viewpoint of emulsion polymerization stability. Is 5 parts by mass or more, more preferably 8 parts by mass or more, and preferably 15 parts by mass or less, more preferably 13 parts by mass or less, and still more preferably 12 parts by mass or less, from the viewpoint of preventing foaming during heating tripping. It is.

The mass ratio [(c1) / (c2)] of the nonionic surfactant (c1) and the nonionic surfactant (c2) added to the aqueous solvent in the step (1) is compatible with polymerization stability and dilution stability. From the viewpoint of making it preferable, it is preferably 0.5 or more, more preferably 1.0 or more, and even more preferably 1.5 or more. Also, from the viewpoint of achieving both polymerization stability and dilution stability, preferably 50 or less, more Preferably it is 10 or less, More preferably, it is 2 or less.
As the aqueous solvent, the above aqueous solvent is preferably used. The amount of the aqueous solvent used is preferably 1 mass times or more, more preferably 2 mass times or more, from the viewpoint of reducing the median diameter of the polymer dispersion with respect to the total amount of monomers used in the step (2) described later. More preferably, it is 3 mass times or more. Moreover, from a viewpoint of productivity, Preferably it is 100 mass times or less, More preferably, it is 10 mass times or less, More preferably, it is 5 mass times or less.

[Nonionic protective colloid-forming agent]
In the production method of the present invention, it is preferable to use a nonionic protective colloid-forming agent together with the cationized starch (B) from the viewpoint of the stability of the polymer dispersion.
Nonionic protective colloid-forming agents include carrageenan, pullulan, sucrose, and derivatives in which nonionic groups are introduced, trehalose, hydroxypropylcellulose, partially saponified polyvinyl alcohol (PVA), and fully saponified polyvinyl alcohol. From the viewpoint of the stability of the polymer dispersion, partially saponified polyvinyl alcohol (PVA) is preferred.
When a nonionic protective colloid-forming agent is used, the amount used is preferably 0.1 from the viewpoint of polymerization stability with respect to 100 parts by mass of the total amount of monomers used in step (2). More than 0.5 parts by weight, more preferably 0.5 parts by weight or more, still more preferably 1 parts by weight or more, and from the viewpoint of polymerization stability, preferably 10 parts by weight or less, more preferably 5 parts by weight or less. Is 2 parts by mass or less, and more preferably 1.5 parts by mass or less.
The mass ratio of the nonionic protective colloid forming agent to the cationized starch (B) (nonionic protective colloid forming agent mass / cationized starch (B) mass) is preferably 1/100 or more from the viewpoint of polymerization stability. More preferably, it is 5/95 or more, more preferably 10/90 or more, preferably 55/45 or less, more preferably 40/60 or less, still more preferably 20/70 or less.

[Various conditions for step (1)]
In the step (1), the order of addition of the cationized starch (B), the surfactant (c1) and the surfactant (c2) to the aqueous solvent is not particularly limited, but from the viewpoint of polymerization stability, the cationized starch ( It is preferable to disperse and suspend B) and optionally the nonionic protective colloid in an aqueous solvent, and then add the surfactant (c1) and the surfactant (c2). The cationized starch (B) and the optionally added nonionic protective colloid are preferably heated when dispersed and suspended.
The cationized starch (B), the surfactant (c1) and the surfactant (c2) may be added all at once from the viewpoint of solubility, or may be added by dividing or dropping.
When adding the cationized starch (B), the surfactant (c1) and the surfactant (c2), it is preferable to add them while stirring the system.
The temperature at the time of dissolution of the cationized starch (B) and the optionally added nonionic protective colloid is not particularly limited, but is preferably 80 ° C. or more, more preferably from the viewpoint of dissolution rate and equipment load. It is 85 ° C or higher, more preferably 90 ° C or higher, preferably 120 ° C or lower, more preferably 110 ° C or lower, still more preferably 100 ° C or lower.

<Step (2)>
Step (2) is a step of performing emulsion polymerization of monomer (a1) and monomer (a2) using a polymerization initiator in the solution obtained in step (1). Each component will be specifically described below.

<Monomer (a1)>
The monomer (a1) used in the present invention is a (meth) acrylic acid ester (a1) having an alkyl group having 1 to 16 carbon atoms.
In the present specification, “(meth) acrylic acid” means at least one selected from acrylic acid and methacrylic acid.

The number of carbon atoms of the alkyl group of the (meth) acrylic acid alkyl ester is preferably 1 or more, more preferably 2 or more, still more preferably 3 or more, and preferably 10 or less, from the viewpoint of polymerization stability of emulsion polymerization. More preferably, it is 8 or less, More preferably, it is 6 or less.
The alkyl group may be linear or branched, and includes n-form, sec-form, tert-form, and iso-form.

Specific compounds include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, (meth ) Tert-butyl acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, 2- (meth) acrylic acid 2- Ethyl hexyl is mentioned.
The monomer (a1) is appropriately selected according to the intended use of the polymer dispersion, but preferably from the viewpoint of obtaining the effect of heat stripping in the present invention, methyl (meth) acrylate, (meth) At least one selected from ethyl acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, more preferably methacryl Methyl acid or n-butyl acrylate, more preferably n-butyl acrylate.
The amount of the monomer (a1) used is that the median diameter is reduced and the coefficient of variation of the median diameter is further reduced with respect to 100 parts by mass of the total amount of monomer components of the polymer (A). From this, it is preferably 99.5 parts by mass or less, more preferably 98 parts by mass or less, still more preferably 96 parts by mass or less, and from the viewpoint of interaction between the cationic protective colloid and the emulsified particles, preferably 70 parts by mass. Part or more, more preferably 90 parts by weight or more, and still more preferably 92 parts by weight or more.

<Monomer (a2)>
The monomer (a2) used in the present invention is an ethylenically unsaturated carboxylic acid or a salt thereof.
As the monomer (a2), acid phosphoric acid such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, 2-acrylamido-2-methylpropanesulfonic acid, acid phosphoxyethyl (meth) acrylate, etc. Acids, phosphoxypolyoxyalkylene glycols, (meth) such as xylalkyl (meth) acrylate, acid, phosphoxypolyoxyethylene glycol, mono (meth) acrylate, acid, phosphoxypolyoxypropylene glycol, (meth) acrylate An acrylate is mentioned. Among these, acrylic acid, methacrylic acid, and 2-acrylamido-2-methylpropanesulfonic acid are preferable, and acrylic acid is more preferable from the viewpoint of availability of raw materials.
As the monomer (a2), one type may be used alone, or two or more types may be used in combination.

  The amount of the monomer (a2) used is preferably 5 parts by mass or less, more preferably 3 parts by mass from the viewpoint of reducing the median diameter with respect to 100 parts by mass of the total amount of the monomer component (A) used. Part or less, more preferably 1.5 parts by weight or less, and from the viewpoint of the interaction between the cationic protective colloid and the emulsified particles, preferably 0.01 parts by weight or more, more preferably 0.1 parts by weight or more. More preferably, it is 0.5 parts by mass or more.

<Monomer (a3)>
In the emulsion polymerization, other monomer (a3) may be contained.
Although it does not specifically limit as a monomer (a3), For example, (meth) acrylic-acid hydroxyalkyl ester, (meth) acrylamide, (meth) acrylonitrile, vinyl acetate, styrene etc. are mentioned.

From the viewpoint of ensuring dilution stability, the (meth) acrylic acid hydroxyalkyl ester is preferably a (meth) acrylic acid ω-hydroxyalkyl ester, and preferably has an ω-hydroxyalkyl group having 2 to 6 carbon atoms. .
Specific examples of the hydroxyalkyl acrylate include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. Among these, 2-hydroxyethyl methacrylate (HEMA) is preferable from the viewpoint of raw material availability.
Specific examples of (meth) acrylamides include acrylamide, N, N-dimethylacrylamide, diethylacrylamide, acryloylmorpholine, dimethylaminopropylacrylamide, and hydroxyethylacrylamide.
As the monomer (a3), one type may be used alone, or two or more types may be used in combination.

  The amount of the monomer (a3) used is preferably 25 parts by mass or less, more preferably 20 parts from the viewpoint of reducing the median diameter with respect to 100 parts by mass of the total amount of monomer components of the polymer (A). From the viewpoint of the interaction between the cationic protective colloid and the emulsified particles, preferably 0.8 parts by mass or more, more preferably 1 part by mass or more, still more preferably 10 parts by mass or less. Is 2 parts by mass or more.

<Polymerization initiator>
As a polymerization initiator used in the present invention, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-amidinopropane) Known radical polymerization initiators such as azo compounds such as hydrochloride, organic peroxides such as tert-butylperoxyoctoate and dibenzoyl peroxide, inorganic peroxides such as sodium persulfate, potassium persulfate and ammonium persulfate Can be used. Among these polymerization initiators, an azo compound is preferable from the viewpoint of suppressing aggregation.
A polymerization initiator may be used individually by 1 type, and may be used in combination of 2 or more type.
The total use amount of the polymerization initiator is preferably 0.1 parts by weight or more, more preferably 0.3 parts by weight from the viewpoint of suppressing aggregation with respect to 100 parts by weight of the total use amount of the polymer (A) monomer component. Part or more, more preferably 0.5 part by weight or more, preferably 1 part by weight or less, more preferably 0.6 part by weight or less.

<PH adjuster>
In the step (2) of the present invention, it is preferable to carry out emulsion polymerization in a solution in which the pH is controlled, and the pH of the solution is controlled using a pH adjusting agent before the start of the emulsion polymerization in the step (2). Is preferred.
From the viewpoint of improving the dilution stability of the resulting polymer dispersion, the pH at the time of performing the emulsion polymerization in the step (2) is preferably 5.5 or more, more preferably 6.0 or more, and further preferably 6.5 or more. Moreover, Preferably it is 9.5 or less, More preferably, it is 8.0 or less, More preferably, it is 7.5 or less.
Examples of the pH adjuster include sodium phosphate, sodium hydrogen phosphate, phosphoric acid, sodium citrate carbonate, and sodium bicarbonate.
A pH adjuster may be used individually by 1 type, and may be used in combination of 2 or more type.
When using a pH adjuster, the addition time will not be specifically limited if it is before the emulsion polymerization start of a process (2).
In addition, pH of the solution in this invention means the value which measured the solution before addition of monomer (a1) and (a2) using a pH meter at 20 degreeC.

[Conditions for step (2)]
In the step (2), the method for adding the monomer (a1) and the monomer (a2) to the solution is not particularly limited, and they may be added individually or simultaneously. You may mix and add. In addition, the monomer (a1), the monomer (a2) or a mixture thereof, and the polymerization initiator may be added to the solution all at once, or may be added by a method such as dividing or dropping, It is preferable to carry out by dripping from a viewpoint of a copolymer composition and a conversion rate.

  The temperature during the emulsion polymerization in the step (2) is preferably 50 ° C. or higher, more preferably 55 ° C. or higher, more preferably 60 ° C. or higher, from the viewpoint of the speed of emulsion polymerization and the stability of the emulsion state. Is 100 ° C. or lower, more preferably 90 ° C. or lower, and still more preferably 80 ° C. or lower.

  The polymerization time of emulsion polymerization is preferably 2 hours or more, more preferably 4 hours or more, still more preferably 6 hours or more, and preferably 10 hours or less from the viewpoint of sufficient polymerization and productivity. More preferably, it is 9 hours or less, More preferably, it is 8 hours or less.

The emulsion polymerization is preferably performed with stirring. If the stirring speed is too slow, aggregation due to poor mixing occurs, and if the stirring speed is excessively increased, shear aggregation occurs. The emulsion polymerization is preferably carried out with stirring at a speed that does not cause shear aggregation.
It is preferable from the viewpoint of reducing the residual monomer amount that a polymerization initiator is further added after the emulsion polymerization.

[Heating stripping (step (3))]
The present invention mixes a polymer dispersion with one or more surfactants (D) selected from a cationic surfactant (d1) and a nonionic surfactant (d2) having an HLB of 11 or more, Perform heat stripping.
The step of performing the heat stripping can be performed as the step (3) following the steps (1) and (2). In this case, the polymer dispersion is the polymer dispersion obtained by the step (2).
Heat stripping can be performed, for example, by distilling off volatile components such as water and monomers by distillation under reduced pressure. As the operation method, the polymer dispersion obtained in the step (2) can be stripped as it is, concentrated to a certain concentration, and then returned to the original concentration with an aqueous medium. Moreover, you may repeat operation which adds an aqueous medium previously to the polymer dispersion liquid obtained at the process (2), dilutes, and concentrates to the original density | concentration. From the viewpoint of diffusing the monomer (a1) faster from the inside of the particles to the aqueous phase side which is a continuous phase, the former operation is preferable.
The number of repetitions of the heating stripping step can be performed twice or more from the viewpoint of removing unreacted monomers, but from the viewpoint of processing efficiency, it is preferably 3 times or less, more preferably 2 times or less, and still more preferably. Once.

<Cationic surfactant (d1)>
As the cationic surfactant (d1), a compound represented by the following general formula (3) is preferable from the viewpoint of efficiently removing unreacted monomers and the like.

式（３）中、Ｒ^3aは炭素数８以上２２以下の炭化水素基、Ｘは−ＣＯＯ−又は−ＣＯＮＨ−から選ばれる基であり、Ｒ^3bは炭素数２又は３のアルキレン基である。ｇは０又は１の数である。Ｒ^3cは炭素数１以上３以下のアルキル基である。Ｔ^-は、有機又は無機の陰イオンである。
Ｒ^3aは、未反応単量体を除去する観点から、好ましくはアルキル基、又はアルケニル基であり、より好ましくは、アルキル基である。
Ｒ^3aの炭素数は、未反応単量体を除去する観点から、好ましくは８以上、より好ましくは１２以上、更に好ましくは１４以上であり、同様の観点から好ましくは２２以下、より好ましくは２０以下である。
ｇは、炭素数は未反応単量体を除去する観点から、０の数が好ましい。
Ｒ^3cは、未反応単量体を除去する観点から、メチル基であることが好ましい。
Ｔ^-は、未反応単量体を除去する観点から、好ましくは、ハロゲン化物イオン、炭素数１以上３以下のアルキル硫酸エステルイオン、炭素数１以上１２以下の脂肪酸イオン、炭素数１以上３以下のアルキル基で置換していてもよいベンゼンスルホン酸イオンであり、より好ましくはハロゲン化物イオンであり、更に好ましくは塩化物イオンである。

In Formula (3), R ^3a is a hydrocarbon group having 8 to 22 carbon atoms, X is a group selected from —COO— or —CONH—, and R ^3b is an alkylene group having 2 or 3 carbon atoms. g is a number of 0 or 1. R ^3c is an alkyl group having 1 to 3 carbon atoms. T ⁻ is an organic or inorganic anion.
R ^3a is preferably an alkyl group or an alkenyl group, more preferably an alkyl group, from the viewpoint of removing unreacted monomers.
The number of carbon atoms in R ^3a is preferably 8 or more, more preferably 12 or more, still more preferably 14 or more from the viewpoint of removing unreacted monomers, and preferably 22 or less, more preferably 20 from the same viewpoint. It is as follows.
g is preferably a number of 0 from the viewpoint of removing unreacted monomers.
R ^3c is preferably a methyl group from the viewpoint of removing unreacted monomers.
T ^- is preferably a halide ion, an alkyl sulfate ester ion having 1 to 3 carbon atoms, a fatty acid ion having 1 to 12 carbon atoms, or a carbon atom having 1 to 3 carbon atoms from the viewpoint of removing unreacted monomers. Benzenesulfonate ion optionally substituted with an alkyl group, more preferably a halide ion, and still more preferably a chloride ion.

<Nonionic surfactant (d2)>
The HLB of the nonionic surfactant (d2) is 11 or more from the viewpoint of removing unreacted monomers, preferably 14 or more, more preferably 17 or more, and preferably from the same viewpoint. 20 or less, more preferably 19 or less.
The nonionic surfactant (d2) is preferably a compound represented by the following general formula (4) from the viewpoint of efficiently removing unreacted monomers.
R ⁴ —O— (Z) _m —H (4)
In formula (4), R ⁴ is a linear or branched, saturated or unsaturated hydrocarbon group having 8 to 18 carbon atoms, and Z is at least one selected from ethylene oxide units and propylene oxide units. Show. m shows the number addition mole number of Z, and is a number of 16 or more and 100 or less.
The number of carbon atoms of R ⁴ is preferably 8 or more, more preferably 10 or more from the viewpoint of efficiently removing unreacted monomers, and from the same viewpoint, it is preferably 18 or less, more preferably 14 or less. is there.
R ⁴ is preferably linear from the viewpoint of efficiently removing unreacted monomers.
R ⁴ is preferably saturated from the viewpoint of efficiently removing unreacted monomers.
Z is preferably an ethylene oxide unit from the viewpoint of efficiently removing unreacted monomers.
m is preferably 16 or more, more preferably 19 or more, still more preferably 30 or more, still more preferably 40 or more, from the viewpoint of efficiently removing unreacted monomers, and from the same viewpoint, preferably 100. Below, more preferably 70 or less, and still more preferably 60 or less.

In the heat stripping, a cationic surfactant (d1) and a nonionic surfactant (d2) having an HLB of 11 or more are preferable from the viewpoint of efficiently removing unreacted monomers and preventing aggregation of polymer particles. One or more surfactants (D) selected from the above, more preferably a cationic surfactant (d1), and a polymer dispersion are mixed and subjected to heat stripping.
The amount of the surfactant (D) to be mixed is preferably 0.1 parts by mass or more from the viewpoint of removing unreacted monomers with respect to 100 parts by mass of the continuous phase in the polymer dispersion before heating stripping. , More preferably 0.3 parts by mass or more, still more preferably 0.5 parts by mass or more, and preferably 4.0 parts by mass or less, more preferably 3 from the viewpoint of preventing foaming and bumping of the dispersion. 0.0 parts by mass or less, more preferably 2.0 parts by mass or less, and further preferably 1.5 parts by mass or less.
The continuous phase means a component that forms a continuous phase in the polymer dispersion, and more specifically means a non-solid content in the polymer dispersion.

<Heat stripping conditions>
From the viewpoint of efficiently removing unreacted monomers, the solid content concentration at the start of heating stripping in the step (3) is preferably 1% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass. % Or more, more preferably 18% by mass or more, and from the viewpoint of preventing aggregation of polymer particles, it is preferably 30% by mass or less, more preferably 20% by mass or less.
The solid content concentration at the start of heating stripping can be adjusted by adding an aqueous solvent to the polymer dispersion.
From the viewpoint of efficiently removing unreacted monomers, the temperature of the polymer dispersion at the time of heat stripping is preferably 20 ° C. or higher, more preferably 30 ° C. or higher, and further preferably 40 ° C. or higher. From the viewpoint of preventing this, it is preferably 100 ° C. or lower, more preferably 70 ° C. or lower, and still more preferably 60 ° C. or lower.
From the viewpoint of efficiently removing unreacted monomers, the pressure at the time of heating stripping is preferably 100 kPa or less, more preferably 50 kPa or less, and even more preferably 20 kPa or less in absolute pressure, and from an economic viewpoint, absolute pressure is used. The pressure is preferably 1 kPa or more, more preferably 5 kPa or more, and still more preferably 10 kPa or more.
The solid content concentration at the end of the heating stripping is preferably 15% by mass or more, more preferably 20% by mass or more, from the viewpoint of efficiently removing unreacted monomers and the productivity of the polymer dispersion. The amount is preferably 30% by mass or more, more preferably 33% by mass or more, and preferably 40% by mass, more preferably 35% by mass or less from the viewpoint of preventing aggregation of polymer particles.
The content of the monomer (a1) in the polymer dispersion after completion of the heat stripping is preferably 500 ppm by mass or less, more preferably 100 ppm by mass or less, and further preferably 10 ppm by mass or less from the viewpoint of odor. It is.

  The increase rate of coarse particles of 1.0 μm or more in the polymer particles by the heat stripping is preferably 30% or less, more preferably 1% or less, and still more preferably, from the viewpoint of blendability into the product. Is 0.1% or less. The rate of increase here is the ratio of the number of coarse particles of 1.0 μm or more contained in the raw material polymer dispersion (%) to the ratio of the number of coarse particles of 1.0 μm or more contained in the polymer dispersion after heat stripping. The value (%) minus (%).

  The polymer dispersion of the present invention is used in, for example, garment detergent compositions such as glues, softeners, bleaches, and detergents, or garment finish compositions, adhesives, pressure-sensitive adhesives, paints, and coating agents.

  Hereinafter, the present invention will be described by way of examples. “Parts” means parts by mass, “%” means “% by mass”, and “parts by mass” describes the polymer dispersion at the end of (Step 2) as 100 parts by mass. In Examples and Comparative Examples described later, various measurements and calculation methods were performed by the following methods.

(1) Measurement of median diameter and calculation method of ratio of coarse particles The median diameter of the polymer dispersion was measured using a laser diffraction / scattering particle size distribution analyzer “LA-920” (manufactured by Horiba, Ltd.). As a dilution solvent, distilled water was used, and a relative refractive index of 140a000I was used. As measurement conditions, measurement was performed at 20 ° C., with a flow, with stirring 15 and without ultrasonic waves. The coarse particle ratio was 1.0 μm or more.

(2) Measuring method of solid content It measured using the infrared moisture meter "FD-240" (Kett Science Laboratory). When the measurement temperature was 140 ° C. and the measurement time was 60 seconds, the solid content did not change.

(3) HLB
It was calculated by the Griffin method shown below.
HLB = 20 × sum of formula weight of hydrophilic part / molecular weight

(4) Viscosity Measurement of Cationized Starch Aqueous Solution 15 g of cationized starch was added to 485 g of deionized water, and dissolved or swollen with slow stirring at 90 ° C. for 2 hours. After cooling to 20 ° C., it was supplemented with deionized water reduced by evaporation. The viscosity of the obtained aqueous solution or aqueous dispersion was determined by using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd., model VT-10) and adjusting the spindle to each measured viscosity range. M1, M2, M3, and M4 were used and measured at 20 ° C. under the condition of 6 rpm / 60 seconds.

(5) pH measurement A pH meter “twin pH meter AS-212” (manufactured by Horiba, Ltd.) was used.

(6) Measuring method of n-butyl acrylate It measured using D2000 type HPLC (made by Hitachi High-Technologies Corporation) on the conditions shown below.
Column: ODS column (product name: L-column ODS, size: 4.6 × 150 mm, 5 μm)
Mobile phase A: 0.1% acetonitrile aqueous phosphate solution (deionized water / acetonitrile = volume ratio 70/30)
Mobile phase B: 0.1% acetonitrile aqueous solution of phosphoric acid (deionized water / acetonitrile = volume ratio 80/20)
Gradient conditions: as shown in Table 1 below.

Detector: UV (205 nm)
Column temperature: 40 ° C
Flow rate: 1.0 ml / min
Sample: 5 g of the polymer dispersion was diluted to 100 ml with acetone, allowed to stand, and then allowed to stand. Then, 5 ml of the supernatant was dissolved in acetonitrile and diluted to 50 ml. A 0.45 μm membrane filter (Advantech) Product).

(7) Calculation method of substitution multiples The amount of water distilled off (until the residual n-butyl acrylate was below the detection limit) relative to the solid content.

(8) Calculation method of aggregation suppression effect (evaluation of aggregation suppression effect)
The increase in the ratio of coarse particles of 1.0 μm or more before and after the distillation operation was calculated.
Coarse particle ratio increase (%) = [ratio of coarse particle number of polymer dispersion after distillation operation (%)] − [ratio of coarse particle number of polymer dispersion liquid before distillation operation (%)]

Example 1
(Process 1)
In a nitrogen atmosphere, cationized starch (MX-2075, manufactured by Kao Corporation, nitrogen content = 0.6%, 3% aqueous dispersion viscosity 1350 mPa · s) 1.3 parts, partially saponified polyvinyl alcohol (Nippon Synthesis) Chemical Co., Gosenol GL-05) 0.2 part and deionized water 59.2 parts were added and mixed at room temperature for 30 minutes. Thereafter, the temperature was raised to 90 ° C., stirred gently for 2 hours to dissolve by heating, and then cooled to 65 ° C. Nonionic surfactant (c1) (ethylene oxide adduct of secondary alcohol having 11 to 15 carbon atoms (number average addition mole number of EO 7, HLB12.1), manufactured by Kao Corporation, trade name Emulgen 707), And nonionic surfactant (c2-1) (ethylene oxide adduct of lauryl alcohol (number average addition mole number of EO 12, HLB 14.8), product of Kao Corporation, trade name Emulgen 120), and nonionic interface Activator (c2-2) (ethylene oxide adduct of lauryl alcohol (number average addition mole number of EO: 47, HLB18.4), product name: Emulgen 150, manufactured by Kao Corporation), nonionic surfactant (c1) / Nonionic surfactant (c2-1) / Nonionic surfactant (c2-2) mass ratio (mass ratio 65 / 31.5 / 3.5) It was added the whole amount of the 20% aqueous solution of pre-mixed with liquid 1.7 parts had deionized water 6.6 parts aqueous solution of the cationized starch and partially saponified polyvinyl alcohol. Thereafter, 0.1 part of a phosphate buffer aqueous solution (deionized water / 35% NaOH aqueous solution / 75% phosphoric acid aqueous solution = mass ratio 3/8/89) was added to adjust the protective colloid solution to pH 7.0. did.

(Process 2)
Subsequently, with stirring, 0.3 part of n-butyl acrylate, 0.1 part of methyl methacrylate and 0.03 part of 2,2′-azobis (2-amidinopropane) hydrochloride were added to 1.62 parts of deionized water. The total amount of the 2.0% aqueous solution dissolved in was added and heated to 65 ° C. to initiate polymerization, and then heated to 75 ° C. 4.8 parts of methyl methacrylate, 10.3 parts of n-butyl acrylate, 0.2 part of acrylic acid, 16.1 parts of a mixed solution of 0.8 part of 2-hydroxyethyl methacrylate, and 2,2′-azobis Two solutions of 20% aqueous solution in which 0.05 part of (2-amidinopropane) hydrochloride was dissolved in 11.8 parts of deionized water were dropped into the reaction solution over 5 hours. After completion of the dropwise addition, a total amount of 1.3% aqueous solution in which 0.01 part of 2,2′-azobis (2-amidinopropane) hydrochloride was dissolved in 0.98 part of deionized water was added and held for 2 hours. The obtained polymer aqueous dispersion had a solid content concentration of 19% and a median diameter: 0.12 μm, and the ratio of coarse particles of 1 μm or more was 0%. The total amount of (meth) acrylic acid ester used was 98.8 parts by mass with respect to 100 parts by mass of the total amount of monomer components used in the polymer.

(Process 3)
A cationic surfactant (d1) (28% aqueous solution of stearyltrimethylammonium chloride, trade name Coatamine 86W manufactured by Kao Corporation) was added to the polymer aqueous dispersion obtained in Step 2 with respect to 100 parts of the polymer dispersion. 4 parts (0.8 parts stearyltrimethylammonium chloride per 100 parts continuous phase of the polymer dispersion) were added. Thereafter, 73 parts of deionized water was added to 100 parts of the polymer dispersion so that the solid content concentration was 11%. Next, the temperature in the tank was raised to 52 ° C., the pressure in the tank was slowly reduced to 13 kPa (abs), and distillation was performed for an appropriate time. The solid concentration at the end of the distillation was 20%. No foaming of the polymer dispersion during distillation was observed.

Comparative Example 1
To the polymer aqueous dispersion obtained in Step 2 of Example 1, 73 parts of deionized water was added to 100 parts of the polymer dispersion to a solid concentration of 11% without adding a surfactant. The first distillation was carried out under the same operating conditions. The concentration of solid content after the distillation was 20%. Furthermore, 82 parts of deionized water was added to 100 parts of the polymer dispersion to a solid concentration of 11%, and the second distillation was performed under the same operating conditions as in Example 1. The concentration of solid content after the distillation was 20%.

Example 2
Distillation was performed under the same operating conditions as in Example 1 from the state where the solid content concentration was 19% without adding and diluting deionized water to the polymer dispersion after addition of the surfactant in Step 3 of Example 1. . The solid concentration after completion of the distillation was 34%. No foaming of the polymer dispersion during distillation was observed.

Comparative Example 2
Distillation was carried out under the same operating conditions as in Example 1 without adding a surfactant and deionized water to the polymer aqueous dispersion obtained in Step 2 of Example 1. The solid concentration after completion of the distillation was 36%.

Example 3
A polymer dispersion was obtained in the same manner as in Example 1 except that the steps 2 and 3 were changed to the following steps.
(Process 2)
While stirring the protective colloid solution obtained in Step 1 of Example 1, 0.3 part of n-butyl acrylate, 0.1 part of methyl methacrylate, 2,2′-azobis (2-amidinopropane) hydrochloric acid A total amount of a 2.0% aqueous solution in which 0.03 part of salt was dissolved in 1.62 parts of deionized water was added and heated to 65 ° C. to initiate polymerization, and then heated to 75 ° C. 4.8 parts of methyl methacrylate, 10.3 parts of n-butyl acrylate, 0.2 part of acrylic acid, 16.1 parts of a mixed solution of 0.8 part of 2-hydroxyethyl methacrylate, and 2,2′-azobis The total amount of 20% aqueous solution prepared by dissolving 0.05 parts of (2-amidinopropane) hydrochloride in 11.8 parts of deionized water was added dropwise to the reaction solution over 5 hours. After completion of the dropwise addition, the temperature was raised to 80 ° C., and a total amount of 1.3% aqueous solution in which 0.01 part of ammonium persulfate was dissolved in 0.98 part of deionized water was added and held for 2 hours. The obtained polymer dispersion had a solid content concentration of 19% and a median diameter: 0.12 μm, and the ratio of coarse particles of 1 μm or more was 0%.
(Process 3)
The same amount of the surfactant used in Example 2 was added to the polymer dispersion obtained in Step 2 above, and distillation was performed under the same operating conditions as in Example 1 without adding deionized water. The solid concentration after completion of the distillation was 34%. No foaming of the polymer dispersion during distillation was observed.

Example 4
In the polymer aqueous dispersion obtained in Step 2 of Example 3, 7.3 parts of the surfactant used in Step 3 of Example 3 with respect to the polymer dispersion (based on 100 parts of the continuous phase of the polymer dispersion). Stearyltrimethylammonium chloride (2.5 parts) was added, and deionized water was not added, and distillation was performed under the same operating conditions as in Example 1. The solid concentration after completion of the distillation was 34%. Distillation showed foaming of the polymer dispersion, but there was no problem.

Example 5
To the aqueous polymer dispersion obtained in Step 2 of Example 3, a nonionic surfactant (d2) (ethylene oxide adduct of lauryl alcohol (EO number average addition mole number 47, HLB 18.4), manufactured by Kao Corporation) , 3.3 parts of a 20% aqueous solution of the trade name Emulgen 150) with respect to the polymer dispersion (100 parts of the continuous phase of the polymer dispersion is ethylene oxide adduct of lauryl alcohol (EO number average addition mole number 47, HLB18). 4) 0.8 part) was added, and 73 parts of deionized water was added to 100 parts of the polymer dispersion to a solid concentration of 11%, and then distilled under the same operating conditions as in Example 1. The solid concentration after the distillation was 22%. No foaming was observed during distillation.

Example 6
The same amount of the surfactant used in Example 5 was added to the polymer dispersion obtained in Step 2 of Example 3, and deionized water was not added, and distillation was performed under the same operating conditions as in Example 1. went. The solid concentration after the distillation was 33%. No foaming was observed during distillation.

  According to the present invention, the unreacted monomer can be efficiently removed with a small amount of distilled water in the heating stripping step, and the generation of the amount of aggregates can be suppressed, so that the present invention can be applied to various fields.

Claims (9)

A polymer dispersion containing a (meth) acrylic acid ester monomer (a1) having an alkyl group having 1 to 16 carbon atoms and water, a cationic surfactant (d1) and HLB of 11 or more and the following formula (4) The manufacturing method of a polymer dispersion which has the process of mixing with 1 or more types of surfactant (D) chosen from nonionic surfactant (d2) represented by these, and performing heat stripping.
R ⁴ —O— (Z) _m —H (4)
[In the formula (4), R ⁴ is a linear or branched hydrocarbon group having 8 to 18 carbon atoms, which is saturated or unsaturated, and Z represents an ethylene oxide unit. m shows the number addition mole number of Z, and is a number of 16 or more and 100 or less. ]   The method for producing a polymer dispersion according to claim 1, wherein the surfactant (D) is a cationic surfactant (d1).   The method for producing a polymer dispersion according to claim 1 or 2, wherein a solid content concentration of the polymer dispersion at the start of heating stripping is 1% by mass or more and less than 30% by mass.   The amount of the surfactant (D) mixed is 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the continuous phase in the polymer dispersion before heat stripping. The manufacturing method of the polymer dispersion liquid in any one of.   The method for producing a polymer dispersion according to any one of claims 1 to 4, wherein a solid content concentration of the polymer dispersion at the end of heating stripping is 15% by mass or more and less than 40% by mass.   The polymer dispersion before heat stripping is a dispersion of polymer (A) obtained by emulsion polymerization of a monomer containing (meth) acrylic acid ester (a1) having an alkyl group having 1 to 16 carbon atoms. The manufacturing method of the polymer dispersion liquid in any one of Claims 1-5.   (Meth) acrylic acid ester having an alkyl group having 1 to 16 carbon atoms in a liquid containing a cationized starch (B), a nonionic surfactant (C), and water as the polymer dispersion before heat stripping The production of a polymer dispersion according to claim 6, which is a dispersion of a polymer (A) obtained by emulsion polymerization of a monomer containing (a1) and an ethylenically unsaturated carboxylic acid or a salt thereof (a2). Method.   The polymer according to claim 7, wherein the amount of the (meth) acrylic acid ester (a1) used is 70 parts by mass or more and 99.5 parts by mass or less with respect to 100 parts by mass of the total amount of monomer components of the polymer (A). A method for producing a dispersion.   (Meth) acrylic acid ester having an alkyl group having 1 to 16 carbon atoms in a liquid containing a cationized starch (B), a nonionic surfactant (C), and water as the polymer dispersion before heat stripping (A1), ethylenically unsaturated carboxylic acid or salt thereof (a2), and (meth) acrylic acid hydroxyalkyl ester, (meth) acrylamides, (meth) acrylonitrile, vinyl acetate, and styrene The manufacturing method of the polymer dispersion liquid of Claim 7 or 8 which is a dispersion liquid of the polymer (A) obtained by performing emulsion polymerization of the monomer containing this monomer (a3).