JP2010065139A - Method of producing latex and acrylic sol composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing acrylic polymer particles excellent in storage stability when the particles are converted into a plastisol, and to provide: a plastisol excellent in storage stability, having advantageous balance between strength and elasticity and suppressing tuck in a coating film formed on a textile; the use of the plastisol in a textile ink; and articles obtained from the textile ink. <P>SOLUTION: This method of producing a latex comprises: feeding a monomer (A) into a polymerization reactor; performing the polymerization at a concentration less than a critical micelle concentration to produce seed particles; feeding into the reactor, 100 pts.mass of a monomer (B) and 0.005 to 0.040 pt.mass of a radical polymerization initiator to perform the polymerization; and feeding a monomer (C) into the reactor to perform the polymerization. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a latex in which acrylic polymer fine particles for diisononylcyclohexanedicarboxylic acid ester (DINCH) are dispersed, and a plastisol or textile ink obtained by using the latex. More specifically, the present invention has excellent storage stability and is suitable for the environment. The present invention relates to a polymer and a plastisol composition that have a low load and are excellent in flexibility in a coating film formed using a textile ink.

Pasty materials in which fine particles of thermoplastic polymer are dispersed in a plasticizer are collectively referred to as plastisol. In particular, plastisol using a vinyl chloride polymer has been widely used for various years as a vinyl chloride sol in various industrial fields. Yes. However, since vinyl chloride sols cause environmental problems such as dioxins when incinerated at low temperatures, acrylic plastisols using acrylic polymer fine particles have been proposed in order to reduce the environmental burden (patent document) 1)), and its practical use is progressing.

In recent years, the required performance for acrylic plastisols has become even higher.
Textile inks are used to print designs on various textiles and to form coatings having various functions. Textile ink contains plastisol as a coating film forming component and a functional component such as a pigment, and a coating film formed on the textile using this component is required to have flexibility to follow the deformation of the textile. However, the flexibility of the obtained coating film and the storage stability of the plastisol contained in the textile ink are contradictory properties, and a textile ink that satisfies these requirements is demanded. Acrylic plastisols tend to lack storage stability, such as the sol state changing during storage. For textile inks using acrylic plastisol, the flexibility of the resulting coating film and the storage stability of the textile inks can be adjusted. Extremely difficult.
In the case of storage stability, there is a problem in that the viscosity increases when the ink is transported, and the transport destination is limited to the vicinity, or the transportable time is limited. In addition, when a large number of inks are adjusted for multicolor printing, if the remaining ink cannot be stored for a long period of time, the amount of ink to be discarded increases, which is not preferable from the environmental and economic viewpoints.
Patent Document 2 describes an example in which a particle dispersion in which an azo initiator is dissolved is dropped onto particles after seed adjustment by soap-free polymerization. Here, an acrylic system for molding material is used. An example of producing polymer fine particles is shown, and storage stability with a plasticizer was not considered.
The use of non-phthalate plasticizers has been discontinued in some fields in order to further reduce the environmental impact of phthalate ester compounds used as plasticizers. is there. Various types of non-phthalate plasticizers have been put into practical use and have been proposed. Examples thereof include benzoate compounds, citrate compounds, and polyester compounds.

However, these plasticizers do not extend to phthalate ester plasticizers in terms of physical properties such as heat resistance and viscosity, and cost. It has not yet replaced ester plasticizers.

Especially for acrylic plastisols, the development of plasticizers has been requested in order to optimize compatibility and wettability with acrylic polymers and to satisfy practical requirements such as gelation performance, storage stability, and viscosity. There is a background.
However, such plasticizers generally have a strong dissolving power in resins, and it has been difficult to achieve both good film properties and long-term storage stability.
Moreover, since the dissolving power was strong, there was a tendency that the tack (stickiness) of the film became remarkable.

International Publication WO00 / 01748 Pamphlet JP 2008-24867 A

  The subject of this invention is providing the manufacturing method of the acrylic polymer particle excellent in storage stability, when it is set as a plastisol. Also provided are plastisols and textile inks that have excellent storage stability and have a good balance between strength and stretchability in coatings formed on textiles, and that suppress tack, and articles obtained therefrom. There is to do.

  As a result of intensive research to solve the above problems, the inventors of the present invention produced acrylic polymer particles in the monomer dispersion when performing drop polymerization on seed particles obtained by soap-free polymerization. It has been found that acrylic polymer fine particles with good storage stability can be obtained by dissolving a predetermined amount of radical polymerization initiator. Moreover, the plastisol obtained from the particles and cyclohexanedicarboxylic acid ester, particularly cyclohexanedicarboxylic acid ester, is extremely excellent in storage stability, and the coating film formed on the textile using this is excellent in both strength and stretchability. It has been found that tack is suppressed, and the present invention has been completed.

（１）
ただし、Ｒ_１、Ｒ_２は独立して炭化水素基を表す
また、本発明は、上記アクリルゾル組成物を含むテキスタイルインク、上記アクリルゾル組成物が塗布された物品である。 That is, the first gist of the present invention is:
The monomer (A) is supplied to the polymerization vessel and polymerized under the condition of less than the critical micelle concentration to produce seed particles, and then the monomer (B) and the radical polymerization initiator are radicalized with respect to 100 parts by mass of the monomer (B). This is a method for producing a latex in which a polymerization initiator is supplied at a ratio of 0.005 to 0.040 parts by mass to perform polymerization, and further, a monomer (C) is supplied to perform polymerization.
The present invention also provides a method for producing a powder by spray drying the latex obtained by the above method, an acrylic sol composition comprising the powder obtained by the production method and a plasticizer, and a plasticizer represented by the following formula (I It is the said acrylic sol composition represented by this.

(1)
However, R < ₁ >, R < ₂ > represents a hydrocarbon group independently Moreover, this invention is a textile ink containing the said acrylic sol composition, and the articles | goods by which the said acrylic sol composition was apply | coated.

  The plastisol containing the powder obtained by the method for producing a latex of the present invention has excellent storage stability, is suitable for textile inks, and can reduce the burden on the environment. The textile ink of the present invention is excellent in the balance between storage stability and flexibility.

Hereinafter, the present invention will be described in detail.

In the present invention, the latex is produced by multistage polymerization. Here, multi-stage polymerization is a method in which a monomer is supplied in multiple stages to carry out polymerization, and at least one of the monomer mixtures constituting the composition of each stage is a monomer having a composition different from the other stages. It is a method of supplying and polymerizing. Examples of the supply method include a method of dropping sequentially or a method of adding continuously. As a result, the so-called core / shell structure (two-layer structure) having a different composition in the central part and its outer layer, and further the shell part or the core part having a plurality of layers (three or more layers structure), seed / core / shell structure It is considered that polymer particles having a multilayer structure such as can be produced. A multilayer structure includes a gradient structure in which the composition continuously changes from the center to the surface. Since the acrylic polymer fine particles have a multilayer structure, the polymer component (core portion) compatible with the plasticizer is formed by the surface layer (shell portion) formed of the polymer component incompatible with the plasticizer. The contact with the plasticizer is suppressed, the gelation of the acrylic polymer particles in the acrylic sol is suppressed, and the storage stability of the acrylic sol and the ink using the same is improved. Furthermore, the strength and stretchability of the coating film obtained using this can be easily adjusted.
In the method for producing a latex of the present invention, it is necessary to include a step of forming seed particles as the first step in that polymer particles having a large particle diameter can be easily obtained. In the step of forming seed particles, in addition to the (meth) acrylates such as methyl methacrylate in the polymerization vessel, the monomer (A) having a functional group such as an acid group is added to the surfactant in the dispersion medium as necessary. It is preferable to disperse under a condition that the concentration is less than the critical micelle concentration, add a polymerization initiator or the like as necessary, and perform polymerization to obtain seed particles. By polymerizing the monomer at a concentration lower than the critical micelle concentration, soap-free polymerization is possible, and seed particles having a relatively large particle size can be obtained.
Examples of the dispersion medium to be used include water. The polymerization initiator used is potassium persulfate, ammonium persulfate, persulfate of sodium persulfate; organic peroxides of benzoyl peroxide and t-butyl hydroperoxide; redox polymerization by a combination of an oxidizing agent and a reducing agent. Of these, which can include initiators, it is preferable to use potassium persulfate, ammonium persulfate, and sodium persulfate persulfate.
The amount of the monomer (A) used for the seed particles is preferably 1% by mass or more and preferably 10% by mass or less based on the total monomer usage. It is preferable to use 1% by mass or more of the monomer (A) because a volume average particle size with a final particle size of 300 nm or more can be easily obtained. The content of 10% by mass is preferable because the generation of aggregates during polymerization can be suppressed.
Preferred examples of the monomer (A) used for seed particle formation include (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth) acrylate. It is done. In order to obtain an appropriate solubility in water of the dispersion medium, it is preferable to use a combination of hydrophilic and hydrophobic monomers. For example, a combination of methyl (meth) acrylate and n-butyl (meth) acrylate or a combination of methyl (meth) acrylate and isobutyl (meth) acrylate is preferable.

An initiator may be added to the dispersion medium in which the monomer (A) is dispersed under a critical micelle concentration, if necessary, and heated as necessary to obtain seed particles by soap-free polymerization. it can. In the polymerization, it is preferable to replace the inside of the system with an inert gas such as nitrogen to reduce the oxygen concentration. Specifically, the dissolved oxygen concentration in the dispersion medium is preferably 2 mg / L, and the gas phase oxygen concentration in the polymerization system is preferably 2% or less, more preferably the gas phase oxygen concentration is 1% or less. preferable. This is because it is easy to obtain a high molecular weight acrylic polymer having a weight average molecular weight (Mw) of 500,000 or more by eliminating polymerization inhibition due to oxygen.
Next, the second stage polymerization will be described.
In the second stage, the polymerization reaction is performed by supplying the second stage monomer (monomer (B)) in the presence of the seed particles obtained in the first stage. The monomer (B) is preferably one that is polymerized and becomes a component having good compatibility with the plasticizer. After obtaining the seed particles, the monomer (B) can be added to the container to initiate the polymerization, or the seed particles can be polymerized in another batch in advance and the polymerization can be performed using this. .

In the second stage, since the storage stability is improved, the polymerization is carried out by supplying 0.005 to 0.040 parts by mass of a radical polymerization initiator per 100 parts by mass of the monomer (B) to the polymerization vessel. The reason why the storage stability is improved by this is unknown, but it is presumed that the storage stability is improved by clarifying the particle morphology.
In order to obtain such an effect, the radical polymerization initiator used is more preferably 0.01 to 0.035 parts by mass or less per 100 parts by mass of the monomer (B). As a supply method, it is preferable to add dropwise the monomer (B) in which the radical polymerization initiator is dissolved.
The following are mentioned as an example of a radical polymerization initiator.
Oil-soluble azo polymerization initiator: 2,2′-azobisisobutyronitrile, 1,1′-azobiscyclohexane 1-carbonitrile, 2,2′-azobis-4-methoxy-2,4-dimethylvalero Nitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, dimethyl-2,2′-azobis (2-methylpropionate), 1,1′-azobis (1-acetoxy-1-phenylethane) , 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), etc. Water-soluble azo polymerization initiator: azobisamidinopropane salt, azobiscyanovaleric acid (salt), 2,2′- Azobis [2-methyl-N- (2-hydroxyethyl) propionamide] etc. Peroxide polymerization initiator: benzoyl peroxide, etc. Of these, oil-soluble azo radical polymerization initiators It is preferred. Of the oil-soluble azo radical polymerization initiators, 2,2′-azobisisobutyronitrile and 2,2′-azobis-2,4-dimethylvaleronitrile are preferable, and 2,2′-azobis-2,4. -Dimethylvaleronitrile is particularly preferred.
Next, a third-stage monomer (monomer (C)) is supplied to perform polymerization, and a latex in which polymer particles are dispersed in a dispersion medium is obtained. The monomer (C) is preferably one that is polymerized and becomes a component incompatible with the plasticizer.
In addition, it superposes | polymerizes after that and may superpose | polymerize a total of four or more steps.

As the monomer (B), (C) or the subsequent monomer, an industrially available (meth) acrylic acid ester is preferable. Specific examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, and hexyl. (Meth) acrylates of linear alkyl alcohols such as (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate; (meth) acrylates of cyclic alkyl alcohols such as cyclohexyl (meth) acrylate; etc. Can be mentioned. Among these, methyl acrylate can be easily obtained as a monomer, and is preferably used from the viewpoint of industrial practical use. Here, (meth) acrylate is a general term for acrylate and methacrylate.
Among these, as the monomer (B), isobutyl methacrylate (IBMA) is preferable in terms of good compatibility with a low polarity plasticizer. Moreover, it is preferable that the usage-amount of IBMA is 40-70 mass% in the total monomer usage-amount. When the amount of IBMA is 40% by mass or more, favorable film properties can be obtained when mixed with a low-polarity plasticizer such as cyclohexanedicarboxylic acid ester. When the amount of IBMA is 70% by mass or less, storage stability is obtained when mixed with a low-polarity plasticizer such as cyclohexanedicarboxylic acid ester.
In the method for producing a latex of the present invention, it is necessary to supply 90 to 100% by mass of the amount of IBMA used until 80% by mass of all monomers are subjected to dropwise polymerization. By carrying out like this, storage stability becomes favorable and it is preferable from the film | membrane excellent in a softness | flexibility, elongation, and rubber elasticity. The reason for this is considered to be that the IBMA ratio in the particles can be increased at the center and decreased at the surface layer.

Furthermore, the monomer (B), (C) or a monomer thereafter may be a monomer of the above (meth) acrylic acid ester. Monomers that can be copolymerized with the (meth) acrylic acid ester monomer include (meth) acrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, (meth) acrylic acid 2-succinoloyloxyethyl, Carboxyl group-containing unsaturated monomers such as 2-methanoyloxyethyl (meth) acrylate, 2-phthaloyloxyethyl (meth) acrylate, 2-hexahydrophthaloyloxyethyl (meth) acrylate; Sulfonic acid group-containing unsaturated monomers; Phosphoric acid group-containing (meth) acrylates such as 2- (meth) acryloxyethyl acid phosphate; Carbonyl group-containing (meth) acrylates such as acetoacetoxyethyl (meth) acrylate; 2 -Hydroxyethyl (meth) acrylate, 2-hydroxypropyl Hydroxyl group-containing (meth) acrylates such as meth) acrylate; epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate; amino groups such as N-dimethylaminoethyl (meth) acrylate and N-diethylaminoethyl (meth) acrylate Containing (meth) acrylate; acrylamide and derivatives thereof such as acrylamide, diacetone acrylamide, N-methylol acrylamide, N-methoxymethyl acrylamide, N-ethoxymethyl acrylamide, N-butoxymethyl acrylamide; urethane-modified acrylate; epoxy-modified acrylate; silicone Modified acrylate; (poly) edylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,6-hexanediol (Meth) acrylate, polyfunctional monomers such as trimethylolpropane (meth) acrylates, glycidyl (meth) an epoxy group-containing compound such as acrylate.
The proportion of the monomer (B) is preferably 25% by mass or more, and preferably 45% by mass or less, based on the amount of all monomers used, because the flexibility when forming a film tends to be good.
The proportion of the monomer (C) is preferably 5% by mass or more, and particularly preferably 15% by mass or more because the storage stability of the acrylic sol tends to be good.
Here, the sum of the seed (first stage), second stage and third stage monomer amounts is 100% by mass.
Since there exists a tendency for storage stability to become favorable, it is preferable that monomer (C) has more methylmethacrylate content than monomer (B).
After supplying the monomer (B) and before supplying the monomer (C), it is preferable to add a chain transfer agent and / or add a polymerization initiator. The chain transfer agent is not particularly limited and may be appropriately selected from known chain transfer agents. For example, n-octyl mercaptan, n-dodecyl mercaptan, n-lauryl mercaptan, tert-dodecyl mercaptan, thiol. Examples include octyl glycolate, methoxybutyl thioglycolate, and tridecyl mercaptopropionate. The amount of the chain transfer agent is not particularly limited, but it is preferable to use 0.05 parts by mass or more with respect to 100 parts by mass of the third-stage monomer mixture because the film tends to be flexible. Since there is a tendency that the storage stability is improved, it is preferably used in an amount of 3 parts by mass or less, more preferably 1.5 parts by mass or less.
Preferred examples of the additional initiator include water-soluble peroxides such as hydrogen peroxide and persulfate, and redox systems of peroxides and reducing agents. Of these, water-soluble peroxides are preferably used, and among them, potassium persulfate, ammonium persulfate, and sodium persulfate persulfate are particularly preferable.
As a method for adding an initiator, there are a method in which powder is directly charged and a method in which an initiator dissolved in water is added. From the viewpoint of suppressing the formation of aggregates, an initiator dissolved in water is used. The charging method is preferred.

As a method for taking out the polymer powder from the polymer dispersion after completion of such a polymerization step, a spray drying method (spray drying method) is preferable. By spray-drying method, which makes it easy to create loosely agglomerated states where primary particles are not firmly bonded in agglomerated particles (secondary particles or higher order structure) in which many primary particles are aggregated The recovery method is preferable from the viewpoint of improving dispersibility.
The particles constituting the polymer powder include primary particles containing the polymer, particles in which the primary particles are aggregated by cohesive force, or secondary particles such as particles that are fused to each other by heat. Any of particles having a higher-order structure may be used by subjecting the secondary particles to a treatment such as granulation. Higher-order structure of acrylic polymer particles is intended to improve workability such as suppression of powdering of acrylic polymer particles and improvement of fluidity, and physical properties such as suppression of gelation to plasticizer in acrylic sol. In the method for producing a latex of the present invention, the volume average particle diameter of the obtained polymer fine particles is preferably 300 nm or more, more preferably 400 nm or more, More preferably, it is 500 nm or more. The particle diameter of 300 nm or more is preferable because the initial viscosity when made into an acrylic sol is sufficiently low and the storage stability tends to be good.
Here, the volume average particle diameter is the volume average primary particle diameter in an aqueous dispersion of polymer particles prepared so that the transmittance is in the range of 75 to 95%. The value measured using (LA-920 manufactured by HORIBA, Ltd.) can be adopted.

  The acrylic polymer preferably has a weight average molecular weight (Mw) of 500,000 to 3,000,000. If the molecular weight of the acrylic polymer is 500,000 or more, it has excellent storage stability in the plastisol using this, and can form a coating film having an appropriate strength. It can suppress that plastisol becomes high viscosity.

  The plasticizer used in the acrylic sol composition of the present invention is not particularly limited, and may be appropriately selected from known plasticizers. Specific examples of these plasticizers include dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, di-2-ethylhexyl phthalate, di-n-octyl phthalate, diisononyl phthalate, diisodecyl phthalate, and butyl benzyl phthalate. Phthalate ester plasticizers; dimethyl adipate, dibutyl adipate, diisobutyl adipate, dihexyl adipate, di-2-ethylhexyl adipate, diisononyl adipate, dibutyl diglycol adipate and the like adipate ester plasticizers; trimethyl phosphate, triethyl phosphate, tributyl phosphate, Tri-2-ethylhexyl phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricres Phosphate ester plasticizers such as phosphate, trixylenyl phosphate, cresylphenyl phosphate; Trimellitic ester plasticizers such as tri-2-ethylhexyl trimellitate; dimethyl sebacate, dibutyl sebacate, di-2- Sebacic acid ester plasticizers such as ethylhexyl sebacate; Aliphatic polyester plasticizers such as poly-1,3-butanediol adipate; Epoxidized ester plasticizers such as epoxidized soybean oil; Alkylsulfonic acid phenyl esters Alkyl sulfonic acid phenyl ester plasticizer; Alicyclic dibasic acid ester plasticizer; Polypropylene plasticizer such as polypropylene glycol and polybutylene glycol; Citric acid esters such as acetyltriethyl citrate and acetyltributyl citrate Raised Rukoto can. These plasticizers can be used alone or in combination of two or more.

Among these plasticizers, it is particularly preferable to use a cyclohexanecarboxylic acid ester represented by the formula (1) because storage stability is improved.

（１）
ただし、Ｒ１、Ｒ２は独立して炭化水素基を表す

(1)
However, R1 and R2 independently represent a hydrocarbon group.

In the formula, R ₁ and R ₂ independently represent a hydrocarbon group. The hydrocarbon group represented by R ₁ and R ₂ is preferably selected from a phenyl group or an alkyl group. The alkyl group preferably has 3 to 10 carbon atoms, and is an isononyl group having 9 carbon atoms. Is particularly preferable because it can provide a plastisol having excellent compatibility with an acrylic polymer and excellent storage stability.

As for the compounding quantity of the said cyclohexane dicarboxylic acid ester, 30-400 mass parts is preferable with respect to 100 mass parts of polymer powder. If it is 30 parts by mass or more, a textile ink capable of forming a coating film having strength can be provided, and if it is 400 parts by mass or less, a textile ink capable of forming a coating film having excellent stretchability can be provided. Can do.
When the acrylic sol is used for textile ink, the content of phthalate plasticizer, which is a problem in terms of endocrine disturbance problems such as di-2-ethylhexyl phthalate and diisononyl phthalate, should be 1000 ppm or less in the plastisol. Is preferable, and it is more preferable that it is 500 ppm or less.

The plasticizer described above can be used in combination with a cyclohexanedicarboxylic acid ester.
These plasticizers are preferably used in an amount of 100 parts by mass or less based on 100 parts by mass of the cyclohexanedicarboxylic acid ester.

  The acrylic sol of the present invention may contain various additives described below within a range not impairing the functions of the polymer particles and the plasticizer.

  The textile ink of the present invention contains a functional component together with the plastisol, and can form a coating film imparted with functionality such as colorability, concealability, weight reduction and design. Examples of such functional components include natural inorganic pigments such as clay, barite, mica, and ocher, and synthetic inorganic inorganic materials such as titanium oxide, zinc yellow, barium sulfate, zinc oxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, and carbon black. Pigments, metal powders such as aluminum powder and zinc powder, natural dye-based pigments such as madder lake, nitroso-based, azo-based, phthalocyanine-based, basic dye-based, organic fluorescent-based pigments such as synthetic organic pigments, mineral fillers And fillers such as synthetic fillers or vegetable fillers. Examples of the filler include fiber glass, wood powder, fly ash, cellulose fiber, rice husk, nut shell, hollow sphere, plastic sphere, fumed silica, and glass sphere. In order to improve the concealability, it is preferable to contain titanium oxide.

  The content ratio of the functional component is preferably 0.01 parts by mass or more and more preferably 0.1 parts by mass or more with respect to 100 parts by mass of the polymer powder in order to obtain effects such as coloring. preferable. Moreover, in order to obtain favorable coating-film strength, it is preferable that it is 400 mass parts or less with respect to 100 mass parts of polymer powder, and it is more preferable that it is 300 mass parts or less.

  The textile ink is an antioxidant, a non-halogen flame retardant, a viscosity modifier, a diluent, an antifoaming agent, an antifungal agent, an antibacterial agent, and a surfactant as long as the functions of the plastisol and functional components are not impaired. Additives such as lubricants, ultraviolet absorbers, fragrances, leveling agents, and adhesives can be blended.

  The textile ink can be prepared by mixing and stirring the polymer powder, plasticizer, functional component and, if necessary, the additive, dissolver, kneader, planetary mixer, three roll mill, etc. The stirrer can be used.

  Textiles that form a coating film using the textile ink may be any of fabrics such as woven fabrics and knitted fabrics, felts, and nonwoven fabrics. Specifically, clothes such as shirts, trainers, aprons, socks and gloves, miscellaneous goods such as shoes and bags, upholstery items such as curtains, tablecloths and tapestries, furniture such as chairs and sofas, seats for vehicles, headrests , Tonneau covers, sun visors, and other canvases.

  As a method for forming a coating film on these textiles, direct printing such as screen printing, thermal transfer printing, or the like can be applied. Thermal transfer printing is a method of forming a coating film by applying a textile ink composition onto a release paper or the like and then heat-pressing the gelled film obtained by heating to the textile. The coating film formed on the textile is solidified by heating. The heating conditions can be appropriately selected depending on the thickness of the applied film and the composition, and examples thereof include 100 ° C. to 200 ° C., 1 second to 5 minutes.

Hereinafter, the present invention will be described in detail with reference to examples.
[Example 1] Synthesis of acrylic polymer A1 Into a 2 liter four-necked flask equipped with a thermometer, a nitrogen gas introduction tube, a stirring rod, a dropping funnel, and a cooling tube, 544 g of pure water was placed, and 60 minutes was sufficient. Nitrogen gas was passed to replace the dissolved oxygen in the pure water. Nitrogen gas was switched to flow, and 14.7 g of methyl methacrylate (MMA) as monomer (A) (5.4% by mass with respect to all monomers)
IBMA 31.3g
The mixture was heated to 80 ° C. while stirring at 180 rpm. When the internal temperature reached 80 ° C., 0.16 g of potassium persulfate dissolved in 20 g of pure water was added all at once, and soap-free polymerization was started. Stirring was continued for 60 minutes at 80 ° C. to obtain a seed particle dispersion.

Subsequently, an emulsion of monomer (B) (
MMA179.0g
IBMA 381.0g
Sodium dialkylsulfosuccinate (manufactured by Kao Corporation, “Perex O-TP”) 5.6 g
Radical polymerization initiator (Wako Pure Chemical Industries, Ltd., “V-65”, 2,2′-azobis-2,4-dimethylvaleronitrile) 0.12 parts pure water 280.0 g
Were mixed and stirred and emulsified for 2.5 hours, followed by continuing stirring at 80 ° C. for 1 hour to obtain a second dropped polymer dispersion.

Subsequently, 0.16 g of potassium persulfate dissolved in 40.0 g of pure water was added to the second dropping polymer dispersion, and an emulsion of monomer (C) (
MMA 240g,
2-ethylhexyl thioglycolate (manufactured by Sakai Chemical Co., Ltd.) 0.32 g,
Sodium dialkylsulfosuccinate (manufactured by Kao Corporation, “Perex O-TP”) 2.4 g Pure water 120.0 g
The mixture was stirred and emulsified for 1.5 hours, and then stirred at 80 ° C. for 1 hour to obtain a third dropped polymer dispersion.

  After cooling the obtained third dropping polymer dispersion to room temperature, an inlet temperature of 150 ° C., an outlet temperature of 55 ° C., and an atomizer speed using a spray dryer (manufactured by Okawara Chemical Co., Ltd., type L-8). Acrylic polymer A1 was obtained by spray drying at 20000 rpm.

(Preparation of acrylic sol composition)
100 parts by mass of DINCH (manufactured by BASF) as a plasticizer and 100 parts by mass of acrylic polymer A1 are put into a plastic container, and mixed and stirred at atmospheric pressure for 10 seconds with a vacuum mixer (ARV-200, manufactured by Sinky Corporation). After that, the pressure was reduced to 20 mmHg, and the mixture was further stirred for 90 seconds for defoaming to obtain a uniform acrylic sol. The storage stability of the obtained acrylic sol was evaluated by the following method. Furthermore, a coating film was formed using this, and the elastic modulus was measured.

[Storage stability]
Within 3 hours after the preparation of the acrylic sol, the viscosity is measured at a measurement temperature of 25 ° C. and a rotation speed of 10 rpm using a Brookfield type viscometer (manufactured by Toki Sangyo Co., Ltd., BH type viscometer, No. 7 rotor), This was the initial viscosity. The temperature was kept in a constant temperature bath at 40 ° C., taken out after 10 days, and the viscosity was measured again under the same conditions. This was taken as the viscosity after storage. The thickening rate S of the acrylic sol was calculated from the following formula (unit:%), and the storage stability was evaluated according to the following criteria based on the calculated value. The results are shown in Table 3.

S = [(viscosity after storage / initial viscosity) -1] × 100 (%)
A: Less than 100 Δ: 100 or more and less than 180 ×: Gelation from 180 or more.

[Elastic modulus of coating film]
The acrylic sol obtained on a Teflon (registered trademark) -coated iron plate was applied to a thickness of 2 mm and gelled by heating at 130 ° C. for 20 minutes to obtain a uniform coating film. The acrylic sol coating film peeled off from the release paper was punched into a dumbbell No. 2 type (JIS K6251) and used as a test piece. About this test piece, the test temperature is 25 ° C., the test speed is 200 mm / min. Under the above conditions, a tensile test was carried out with a tensile measuring device (manufactured by Shimadzu Corporation) (trade name “Autograph AG-IS 5 kN”).
In the above tensile test, the tensile modulus of the coating film was evaluated according to the following criteria. The results are shown in Table 3.
A: 3 MPa or less ×: 3 MPa or more

[Example 2, Comparative Examples 1-2] Preparation of acrylic sol Except for using the initiator shown in Table 1, polymers A2 to A4 were obtained in the same manner as in Example 1, and acrylic sols were prepared for each of them. Evaluation was performed.

「Ｖ−６５」２，２’−アゾビス−２，４−ジメチルバレロニトリル（和光純薬（株）製、商品名：Ｖ−６５）
「ＡＩＢＮ」２，２’−アゾビスイソブチロニトリル、
（＊）モノマー(Ｂ)１００部に対する開始剤使用量

“V-65” 2,2′-azobis-2,4-dimethylvaleronitrile (manufactured by Wako Pure Chemical Industries, Ltd., trade name: V-65)
“AIBN” 2,2′-azobisisobutyronitrile,
(*) Amount of initiator used for 100 parts of monomer (B)

（注）表２中の数字は質量部を示す。
「ＤＩＮＣＨ」：ＢＡＳＦ社製シクロヘキサンジカルボン酸エステル（商品名「ヘキサモールＤＩＮＣＨ」）

(Note) The numbers in Table 2 indicate parts by mass.
“DINCH”: Cyclohexanedicarboxylic acid ester manufactured by BASF (trade name “Hexamol DINCH”)

Comparative Example 1 is an example in which the amount of radical polymerization initiator added in the monomer (B) is large. The flexibility of the membrane was good, but the storage stability was poor. Comparative Example 2 was an example where no radical polymerization initiator was added, but the storage stability was low.
From the above results, it is clear that the acrylic sol containing the acrylic polymer obtained by the production method of the present invention has an excellent balance between storage stability and film physical properties.

Claims (6)

The monomer (A) is supplied to the polymerization vessel and polymerized under the condition of less than the critical micelle concentration to produce seed particles. A method for producing a latex, in which a polymerization initiator is supplied at a ratio of 0.005 to 0.040 parts by mass to perform polymerization, and further, a monomer (C) is supplied to perform polymerization. A method for producing a powder by spray drying the latex obtained by the method of claim 1. An acrylic sol composition comprising a powder obtained by the production method according to claim 2 and a plasticizer. The acrylic sol composition according to claim 3, wherein the plasticizer is represented by the following formula (I).

(1)
However, R ₁ and R ₂ independently represent a hydrocarbon group. A textile ink comprising the acrylic sol composition according to claim 3. An article coated with the acrylic sol composition according to claim 3 or 4.