JP2023152611A - Emulsion, aqueous printing ink composition, overprint varnish composition, and method for producing emulsion - Google Patents

Abstract

To provide an emulsion which makes a resin such as waste plastic usable as a starting substance, has a stable emulsion state similarly to the emulsion prepared using a monomer as a starting substance, makes an emulsion state stable, has characteristics such as excellent glossiness, and can exhibit excellent characteristics even if it is used as an aqueous printing ink composition, an aqueous printing ink composition, an overprint varnish composition, and a method for producing an emulsion.SOLUTION: An emulsion has a core-shell structure having a core part and a shell part, wherein the core part contains a resin dissolvable in a solvent having an SP value of 8-10, the shell part contains a first surface active agent and a second surface active agent different from the first surface active agent, the first surface active agent contains a first (ethylene oxide/propylene oxide) block copolymer having an HLB of 14-20, and the second surface active agent contains a nonionic surface active agent having an HLB of 14-20.SELECTED DRAWING: None

Description

The present invention relates to emulsions, aqueous printing ink compositions, overprint varnish compositions, and methods for producing emulsions. More specifically, the present invention provides an emulsion, an aqueous emulsion, which has a stable emulsified state, has properties such as excellent gloss, and can exhibit excellent properties even when used as an aqueous printing ink composition. The present invention relates to a method for producing a printing ink composition, an overprint varnish composition, and an emulsion.

Conventionally, polystyrene emulsions obtained using styrene monomers as starting materials have been used in various fields (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 2009-40994

By the way, plastics such as polystyrene are widely used for various containers, styrofoam, food trays, cutlery, and the like. In recent years, in response to efforts to reduce the consumption of petroleum resources and the problem of marine plastic waste, there has been a need for technology to reduce and reuse waste plastics such as polystyrene. However, the quality of waste plastics tends to deteriorate during the recycling process. Therefore, it has been difficult to recycle waste plastic in fields with high quality requirements, such as the container and packaging field. Furthermore, when recycling polystyrene, for example, it is time-consuming and costly to decompose the polymer polystyrene into polystyrene monomer and then reuse it, and such work also requires a large amount of energy resources. Become.

On the other hand, in the field of aqueous printing inks, there are aqueous printing inks that are prepared by preparing a polystyrene emulsion using a styrene monomer as a starting material and using the obtained polystyrene emulsion. Such water-based printing inks have excellent properties such as density and transparency. However, it has been extremely difficult to obtain water-based printing inks with such excellent properties using waste plastics.

The present invention was made in view of these problems, and it is possible to use resins such as waste plastics as starting materials, and the emulsified state is stable like emulsions prepared using monomers as starting materials. , an emulsion that has properties such as excellent gloss and can exhibit excellent properties even when used as an aqueous printing ink composition, an aqueous printing ink composition, an overprint varnish composition, and a method for producing an emulsion. The purpose is to provide

As a result of intensive studies to solve the above problems, the present inventors have found that an emulsion that uses two different types of surfactants exhibiting a predetermined HLB together and adopts a core-shell structure has solved the above problems. The present invention has been completed based on the discovery that the problem can be solved. The present invention for solving the above problems mainly includes the following configuration.

(1) It has a core-shell structure having a core part and a shell part, the core part contains a resin soluble in a solvent having an SP value of 8 to 10, and the shell part contains a first surfactant. , a second surfactant different from the first surfactant, and the first surfactant is a first (ethylene oxide/propylene oxide) block copolymer having an HLB of 14 to 20. , wherein the second surfactant includes a nonionic surfactant having an HLB of 14 to 20.

According to such a configuration, the emulsion contains a resin soluble in a solvent having an SP value of 8 to 10. The solvent-soluble resin having an SP value of 8 to 10 may be waste plastic or the like. Therefore, the emulsion of the present invention can contribute to solving environmental problems and the like. Further, the emulsion has a stable emulsion state and has properties such as excellent gloss, similar to emulsions prepared using conventional monomers as starting materials. Emulsions can also exhibit excellent properties even when used as aqueous printing ink compositions.

(2) The solvent-soluble resin having an SP value of 8 to 10 is polystyrene, polymethyl methacrylate, polycarbonate, polyurethane, methyl methacrylate-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, or The emulsion according to (1), containing at least one polyester.

According to such a configuration, the emulsion is stable in its emulsified state, and does not increase in viscosity or cause particle precipitation.

(3) The second surfactant is selected from among (ethylene oxide/propylene oxide) block copolymers, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, or polyglycerin fatty acid esters having an HLB of 14 to 20. The emulsion according to (1) or (2), containing at least one species.

According to such a configuration, the emulsion is finely divided and the dried film has excellent gloss.

(4) The emulsion according to any one of (1) to (3), wherein the shell portion contains at least one of styrene-maleic acid and rosin.

According to such a configuration, the emulsion has better properties such as transparency and scratch resistance.

(5) An aqueous printing ink composition comprising the emulsion according to any one of (1) to (4).

According to such a configuration, the aqueous printing ink composition has excellent properties such as density, transparency, scratch resistance, abrasion resistance, water abrasion resistance, and blocking resistance.

(6) An overprint varnish composition comprising the emulsion according to any one of (1) to (4).

According to such a configuration, the overprint varnish composition has excellent properties such as gloss and scratch resistance.

(7) A varnish preparation step in which a varnish is prepared by dissolving a resin that can be dissolved in a solvent having an SP value of 8 to 10 in the solvent, and a varnish preparation step in which the varnish is mixed into an aqueous phase containing a dispersant to form an oil-in-water solution. The dispersant comprises a first emulsification step of producing a type emulsion, a second emulsification step of making the oil-in-water emulsion fine, and a solvent removal step of distilling off the solvent by distillation under reduced pressure. The first surfactant includes a first surfactant and a second surfactant different from the first surfactant, and the first surfactant has a first (ethylene oxide/ (propylene oxide) block copolymer, and the second surfactant includes a nonionic surfactant having an HLB of 14 to 20.

According to such a configuration, the method for producing an emulsion can produce an emulsion using a resin soluble in a solvent having an SP value of 8 to 10 as a starting material. The solvent-soluble resin having an SP value of 8 to 10 may be waste plastic or the like. Therefore, the emulsion manufacturing method of the present invention can contribute to solving environmental problems and the like. Furthermore, the resulting emulsion has a stable emulsion state and has excellent properties such as gloss, similar to emulsions prepared using conventional monomers as starting materials. Moreover, the resulting emulsion can exhibit excellent properties even when used as an aqueous printing ink composition.

(8) a varnish preparation step of preparing a varnish by dissolving a resin soluble in a solvent having an SP value of 8 to 10 in the solvent; a heating step of adding a dispersant to the varnish and heating it; An emulsification step in which an aqueous phase is continuously added to the heated varnish to invert the emulsion from an oil phase to an aqueous phase, and a solvent removal step in which the solvent is distilled off by distillation under reduced pressure, The dispersant includes a first surfactant and a second surfactant different from the first surfactant, and the first surfactant has a HLB of 14 to 20. 1 (ethylene oxide/propylene oxide) block copolymer, and the second surfactant includes a nonionic surfactant having an HLB of 14 to 20.

According to such a configuration, the method for producing an emulsion can produce an emulsion using a resin soluble in a solvent having an SP value of 8 to 10 as a starting material. The solvent-soluble resin having an SP value of 8 to 10 may be waste plastic or the like. Therefore, the emulsion manufacturing method of the present invention can contribute to solving environmental problems and the like. Furthermore, the resulting emulsion has a stable emulsion state and has excellent properties such as gloss, similar to emulsions prepared using conventional monomers as starting materials. Moreover, the resulting emulsion can exhibit excellent properties even when used as an aqueous printing ink composition.

According to the present invention, a resin such as waste plastic can be used as a starting material, and like an emulsion prepared using a monomer as a starting material, the emulsified state is stable and has properties such as excellent gloss. It is possible to provide an emulsion, an aqueous printing ink composition, an overprint varnish composition, and a method for producing an emulsion that can exhibit excellent properties even when used as an aqueous printing ink composition.

<Emulsion>
The emulsion of one embodiment of the present invention has a core-shell structure having a core portion and a shell portion. The core portion contains a resin that can be dissolved in a solvent and has an SP value of 8 to 10. The shell portion includes a first surfactant and a second surfactant different from the first surfactant. The first surfactant includes a first (ethylene oxide/propylene oxide) block copolymer having an HLB of 14-20. The second surfactant includes a nonionic surfactant with an HLB of 14-20. Each will be explained below.

(Emulsion core)
The core portion contains a resin that can be dissolved in a solvent and has an SP value of 8 to 10. The resin that can be dissolved in a solvent having an SP value of 8 to 10 is not particularly limited. For example, resins that can be dissolved in solvents having an SP value of 8 to 10 include polystyrene, polymethyl methacrylate, polycarbonate, polyurethane, methyl methacrylate-styrene copolymer, or acrylonitrile-butadiene-styrene copolymer, or polyester. As a result, the emulsion has a stable emulsified state, and does not thicken or cause particles to precipitate.

Note that in the "resin soluble in a solvent having an SP value of 8 to 10" in this embodiment, "dissolvable" means that 15 g or more of the resin dissolves in 100 g of the solvent at 10 to 60°C. Examples of "solvents with an SP value of 8 to 10" include butyl acetate (SP value = 8.5), ethyl acetate (SP value = 9.1), xylene (SP value = 8.8), These include toluene (SP value = 8.8), benzene (SP value = 9.2), methyl ethyl ketone (SP value = 9.3), etc.

Further, the solvent-soluble resin having an SP value of 8 to 10 may be a synthetic product, or may be a resin recovered from waste plastic or the like. When resin recovered from waste plastics and the like is used, the emulsion of this embodiment can contribute to solving environmental problems and the like.

The core part of the emulsion of this embodiment is made of a resin soluble in a solvent having an SP value of 8 to 10, as well as polyolefin resins other than those mentioned above, polyamide resins, polyester resins, poly(meth)acrylate resins, and polychlorinated resins. It may also contain vinyl resins, mixed resins thereof, and the like.

The poly(meth)acrylate resin is not particularly limited. For example, poly(meth)acrylate resins include acrylic esters and methacrylic esters such as ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, 3-ethoxypropyl Acrylic acid ester derivatives and methacrylic acid ester derivatives such as acrylate, 3-ethoxybutyl acrylate, and hydroxyethyl methacrylate, acrylic acid aryl esters and acrylic acid aralkyl esters such as phenyl acrylate and benzyl acrylate, diethylene glycol, triethylene glycol, It is a polymer of monoacrylic acid esters of polyhydric alcohols such as glycerin.

Polyethylene resins are mainly made of high-density polyethylene, medium-density polyethylene, linear low-density polyethylene, ethylene, etc., and are copolymerized with α-olefins such as propylene, butene, hexene, heptene, octene, and 4-methylpentene-1. maleic acid-modified ethylene/vinyl acetate copolymer, ethylene/vinyl acetate copolymer, ethylene/acrylic acid copolymer, ethylene/acrylic acid alkyl ester copolymer, ethylene/methacrylic acid alkyl ester copolymer metal salts of ethylene/methacrylic acid copolymers (metals include zinc, aluminum, lithium, sodium, potassium, etc.), ethylene/cyclic olefin copolymers, and maleic acid-modified polyethylene.

Polypropylene resins are propylene homopolymers such as isotactic homopolypropylene and syndiotactic homopolypropylene, which are made by homopolymerizing propylene, and are mainly composed of propylene, including ethylene, 1-butene, 1-hexene, 1-heptene, and 1-octene. , propylene copolymers copolymerized with α-olefins such as 4-methyl-1-pentene.

The content of the solvent-soluble resin having an SP value of 8 to 10 in the core portion is preferably 10% by mass or more, more preferably 50% by mass or more. Further, the content of the solvent-soluble resin having an SP value of 8 to 10 in the core portion may be 100% by mass, and is preferably 80% by mass or less. When the content of polystyrene is within the above range, the resulting emulsion has a stable emulsified state and a fine particle size.

(Emulsion shell part)
The shell portion includes a first surfactant and a second surfactant different from the first surfactant.

- First surfactant The first surfactant includes a first (ethylene oxide/propylene oxide) block copolymer having an HLB of 14 to 20. The first (ethylene oxide/propylene oxide) block copolymer is not particularly limited. For example, the first (ethylene oxide/propylene oxide) block copolymer has a structure shown in the following formula.

In the above formula, R ₁ and R ₂ each independently represent an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. Examples of the alkyl group having 1 to 4 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, and tert-butyl group. (x+z) represents the number of added moles of the EO (ethylene oxide) structural unit, and y represents the number of added moles of the PO (propylene oxide) structural unit. [(x+z)/(x+z+y)] is 0.2 to 0.8, preferably 0.4 to 0.7. Further, 60≦x+y+z≦100.

The HLB of the first (ethylene oxide/propylene oxide) block copolymer may be 14 or more, and preferably 15 or more. Further, the HLB only needs to be 20 or less, and preferably 19 or less. When the HLB is less than 14, the resulting emulsion tends to have an unstable emulsified state. Note that HLB is used in the field of surfactants and represents the balance between the hydrophilic part and lipophilic part of the molecule (hydrophile-lipophile balance), and is expressed by the Griffin equation (for a certain amount of oil) shown below. It can be determined by applying the formula (based on the experimental value obtained from the measurement of emulsification efficiency and the weight fraction of the hydrophilic part).
[Griffin's formula] HLB = (100/5) x hydrophilic group weight/(hydrophilic group weight + hydrophobic group weight)

Specific examples of the first (ethylene oxide/propylene oxide) block copolymer that satisfies the above HLB are the ADEKA PLURONIC series manufactured by ADEKA Co., Ltd., the NUPOL series manufactured by Sanyo Chemical Industries, Ltd., and the PLURONIC series manufactured by BASF Corporation. (PLURONIC and PLURONIC are registered trademarks).

The mass average molecular weight (Mw) of the first (ethylene oxide/propylene oxide) block copolymer is preferably 5,000 or more, more preferably 10,000 or more, and 15,000 or more. is even more preferable. The mass average molecular weight (Mw) of the first (ethylene oxide/propylene oxide) block copolymer is preferably 50,000 or less, more preferably 40,000 or less, and 30,000 or less. It is even more preferable that there be. When Mw is within the above range, the resulting emulsion is likely to be stably emulsified. In addition, in this embodiment, Mw is a weight average molecular weight when measured using GPC (gel permeation chromatography) and converted to standard polystyrene.

Because the first (ethylene oxide/propylene oxide) block copolymer is a block copolymer, interparticle cross-linking is less likely than in other polymerization types (graft copolymerization, random copolymerization, etc.). The hydrophilic component spreads efficiently into the liquid, making the emulsion stable.

The content of the first surfactant in the shell portion is preferably 5% by mass or more, more preferably 10% by mass or more. Further, the content of the first surfactant in the shell portion is preferably 80% by mass or less, more preferably 50% by mass or less. When the content of the first surfactant is within the above range, the obtained emulsion has a stable emulsified state and the formed coating film has good water resistance.

-Second surfactant The second surfactant is different from the first surfactant. Further, the second surfactant includes a nonionic surfactant having an HLB of 14 to 20.

The HLB of the second surfactant may be 14 or more, and preferably 15 or more. Further, the HLB only needs to be 20 or less, and preferably 19 or less. When the HLB is less than 14, the resulting emulsion tends to have an unstable emulsified state.

The second surfactant contains at least one of a block copolymer (ethylene oxide/propylene oxide) having an HLB of 14 to 20, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, or polyglycerin fatty acid ester. It is preferable to include. As a result, the emulsion becomes finely divided and the dry film has excellent gloss.

Specific examples of the second surfactant satisfying the above HLB include the ADEKA PLURONIC series manufactured by ADEKA Co., Ltd., the NEUPORT series manufactured by Sanyo Chemical Industries, Ltd., the PLURONIC series manufactured by BASF Corporation, and the PLURONIC series manufactured by Kao Corporation. These include the Emulgen series, the Emanone series, the Rheodol series, the Emulsogen series manufactured by Clariant, and the polyglycerin fatty acid ester manufactured by Sakamoto Pharmaceutical Co., Ltd.

The mass average molecular weight (Mw) of the second surfactant is preferably 5,000 or more, more preferably 10,000 or more, and even more preferably 15,000 or more. Further, the mass average molecular weight (Mw) of the second surfactant is preferably 50,000 or less, more preferably 40,000 or less, and even more preferably 30,000 or less. When Mw is within the above range, the resulting emulsion is likely to be stably emulsified.

When the second surfactant is a block copolymer, interparticle crosslinking is less likely to occur in the block copolymer compared to other polymerization types (graft copolymerization, random copolymerization, etc.). Since the hydrophilic component efficiently spreads into the liquid, the emulsified state becomes stable.

The content of the second surfactant in the shell portion is preferably 5% by mass or more, more preferably 10% by mass or more. Further, the content of the second surfactant in the shell portion is preferably 80% by mass or less, more preferably 50% by mass or less. When the content of the second surfactant is within the above range, the resulting emulsion has a stable emulsified state, and the formed coating film has good water resistance.

-Other components In addition to the above-described first surfactant and second surfactant, the shell portion may contain other components. Other components include styrene maleic acid, styrene acrylic acid, rosins, fatty acid triglycerides, and cellulose ether. Among these, it is preferable that the shell portion contains at least one of styrene-maleic acid and rosin, since the resulting emulsion has better properties such as transparency and scratch resistance.

Styrene maleic acid is an aqueous resin obtained by copolymerizing styrene and maleic acid, such as styrene maleic acid monobutyl ester copolymer.

When styrene maleic acid is contained, the content of styrene maleic acid in the shell portion is preferably 5% by mass or more, more preferably 20% by mass or more. Further, the content of styrene maleic acid in the shell portion is preferably 90% by mass or less, more preferably 60% by mass or less. When the content of styrene maleic acid in the shell part is within the above range, the resulting emulsion has better properties such as transparency and scratch resistance.

Rosins are not particularly limited. For example, rosins include rosin, polymerized rosin, hydrogenated rosin, rosin ester and its hydrogenated product or polymerized product, rosin pentaerythritol and its hydrogenated product or polymerized product, and the like. Among these, the rosins are preferably polymerized rosins or rosin esters.

When rosin is contained, the content of rosin in the shell portion is preferably 5% by mass or more, more preferably 10% by mass or more. Further, the content of rosin in the shell portion is preferably 70% by mass or less, more preferably 40% by mass or less. When the content of rosin in the shell portion is within the above range, the resulting emulsion has better properties such as transparency and scratch resistance.

Fatty acid triglycerides are not particularly limited. For example, fatty acid triglycerides include glyceryl tri-2-ethylhexanoate, glyceryl tricaprylate, glyceryl tricaprate, glyceryl triundecylate, glyceryl tristearate, glyceryl triisostearate, glyceryl tripalmitate, glyceryl triundecanoate, Glyceryl 2-heptylundecanoate, glyceryl tribehenate, glyceryl trimyristate, glyceryl trilaurate, glyceryl trioleate, glyceryl trilinoleate, glyceryl tripalmitoleate, glyceryl triacetyl hydroxystearate, glyceryl triacetyl ricinoleate, trihydroxy Glyceryl stearate, caprylic/capric triglyceride, caprylic/capric/myristic/stearic glyceryl, caprylic/capric/isostearic/adipic triglyceride, caprylic triglyceride / capric acid / lauric acid) glyceryl, tri (caprylic acid / capric acid / linoleic acid) glyceryl, tri (caprylic acid / capric acid / stearic acid) glyceryl, tri tallow fatty acid glyceryl, tri (tallow fatty acid / mink oil fatty acid / cod) Cod liver oil fatty acid) glyceryl, tri (mink oil fatty acid / palmitic acid) glyceryl, tri-coconut oil fatty acid glyceryl, trilanolin fatty acid glyceryl, tri (ricinoleic acid / caproic acid / caprylic acid / capric acid) glyceryl, tri fatty acid (C10-18) glyceryl, Tri-fatty acid (C12-18) glyceryl, hydrogenated tri-fatty acid (C12-18) glyceryl, tri-fatty acid (C12-20) glyceryl, tri-fatty acid (C18-36) glyceryl, tri-branched fatty acid (C10-40) glyceryl, tri-branched fatty acid Fatty acid (C12-31) glyceryl, (hydrogenated rosin/diisostearic acid) glyceryl, tri(palm oil fatty acid/palm kernel oil fatty acid/olive oil fatty acid/macadamia nut oil fatty acid/canola seed oil fatty acid) glyceryl, tri(castor fatty acid/olive fatty acid) ) glyceryl, tri(behenic acid/isostearic acid/eicosandioic acid) glyceryl, tri(mink fatty acid/palmitic acid) glyceryl, etc. Among these, the fatty acid triglyceride is preferably glyceryl tri-2-ethylhexanoate.

When fatty acid triglyceride is contained, the content of fatty acid triglyceride in the shell portion is preferably 5% by mass or more, and more preferably 10% by mass or more. Further, the content of fatty acid triglyceride in the shell portion is preferably 70% by mass or less, more preferably 40% by mass or less. When the content of fatty acid triglyceride in the shell part is within the above range, the resulting emulsion has better properties such as transparency and scratch resistance.

Note that a basic compound may be used in combination with the shell portion in order to dissolve or neutralize components such as the above-mentioned styrene-maleic acid. The basic compound is not particularly limited. For example, basic compounds include inorganic basic compounds such as sodium hydroxide and potassium hydroxide, ammonia, organic amines, and alkali metal hydroxides. Organic amines include alkylamines such as diethylamine, triethylamine, and ethylenediamine, and alkanolamines such as monoethanolamine, ethylethanolamine, diethylethanolamine, diethanolamine, and triethanolamine.

Returning to the explanation of the emulsion as a whole, in this embodiment, two different types of surfactants (first surfactant and second surfactant) are used together, so that, for example, one type of surfactant is used. The emulsion stability of the resulting emulsion is superior to that obtained when the emulsion is obtained.

The mechanism by which the resulting emulsion has excellent emulsion stability by using two different types of surfactants is that the use of surfactants with different molecular weights allows the surfactants to efficiently reach the core surface. This is thought to be due to adsorption.

In this embodiment, a suitable combination of the first surfactant and the second surfactant is Adeka Pluronic F-108 (HLB: 15.8) and Adeka Pluronic F-68 (HLB: 16.0). A combination of Adeka Pluronic F-108 and Nyupol PE78 (HLB: 15.6), a combination of Nyupol PE128 and Adeka Pluronic F108 (HLB: 15.8), a combination of Nyupol PE108 and Adeka Pluronic F108. It is a combination etc. According to these combinations, the resulting emulsion has better emulsion stability.

Emulsions contain water. The content of water is not particularly limited. For example, the water content is preferably 30% by mass or more, more preferably 40% by mass or more. Further, the water content is preferably 80% by mass or less, more preferably 60% by mass or less. When the water content is within the above range, the emulsion can sufficiently undergo phase transition and has excellent stability.

The average particle diameter of the emulsion is preferably 0.05 μm or more, more preferably 0.1 μm or more. Further, the average particle diameter of the emulsion is preferably 5 μm or less, more preferably 1 μm or less. The emulsion of this embodiment has a small particle size, similar to emulsions prepared using conventional styrene monomers as starting materials. Therefore, the emulsion is stable in its emulsified state and has excellent properties such as gloss, transparency, and scratch resistance. Note that the average particle diameter of the emulsion can be measured using a particle size distribution analyzer (Microtrac UPA, manufactured by Nikkiso Co., Ltd.).

As described above, the emulsion of this embodiment contains a resin that can be dissolved in a solvent and has an SP value of 8 to 10. The solvent-soluble resin having an SP value of 8 to 10 may be waste plastic or the like. Therefore, emulsions can contribute to solving environmental problems and the like. Further, the emulsion has a stable emulsion state and has properties such as excellent gloss, similar to emulsions prepared using conventional monomers as starting materials. Emulsions can also exhibit excellent properties even when used as aqueous printing ink compositions.

<Emulsion manufacturing method>
The method for producing the emulsion according to one embodiment of the present invention is not particularly limited. For example, the emulsion is preferably produced by forced emulsification or transfer emulsification.

(forced emulsification)
When producing an emulsion by forced emulsification, the emulsion production method consists of a varnish preparation process in which a varnish is prepared by dissolving a solvent-soluble resin with an SP value of 8 to 10 in a solvent, and an aqueous phase containing a dispersant. The method includes a first emulsification step in which a varnish is mixed to produce an oil-in-water emulsion, a second emulsification step in which the oil-in-water emulsion is made fine, and a solvent removal step in which the solvent is distilled off under reduced pressure. The dispersant includes a first surfactant and a second surfactant different from the first surfactant. The first surfactant includes a first (ethylene oxide/propylene oxide) block copolymer having an HLB of 14-20. The second surfactant includes a nonionic surfactant with an HLB of 14-20.

- Varnish preparation process The varnish preparation process is a process in which a varnish is prepared by dissolving a solvent-soluble resin having an SP value of 8 to 10 in a solvent. The solvent is not particularly limited. For example, the solvent may be esters such as ethyl acetate, aromatic hydrocarbons such as toluene, ketones such as methyl ethyl ketone, and the like.

The solvent-soluble resin having an SP value of 8 to 10 may be resin pellets recovered from waste plastics or the like.

There are no particular limitations on the amount of the solvent to be added to the solvent-soluble resin having an SP value of 8 to 10. For example, the blending amount of the solvent is 300 to 500 parts by mass per 100 parts by mass of a resin that can be dissolved in a solvent having an SP value of 8 to 10.

Dissolution conditions are not particularly limited. For example, the dissolution temperature is 20-40°C and the dissolution time is 10-60 minutes.

- First emulsification step The first emulsification step is a step of mixing a varnish with an aqueous phase containing a dispersant to prepare an oil-in-water emulsion. Note that the oil-in-water emulsion obtained in this first emulsification step is not a stable emulsion but exists in an emulsified state or a suspended state.

The dispersant includes a first surfactant, as described above in connection with the emulsion embodiment, and a second surfactant that is different from the first surfactant.

The content of the dispersant in the aqueous phase is not particularly limited. For example, the content of the first surfactant in the aqueous phase is preferably 0.5% by mass or more, more preferably 2.5% by mass or more. Further, the content of the first surfactant in the aqueous phase is preferably 20% by mass or less, more preferably 10% by mass or less. Further, the content of the second surfactant in the aqueous phase is preferably 0.5% by mass or more, more preferably 2.5% by mass or more. Further, the content of the second surfactant in the aqueous phase is preferably 20% by mass or less, more preferably 10% by mass or less.

The amount of the aqueous phase added to the varnish is not particularly limited. For example, the amount of the aqueous phase blended is 80 to 200 parts by weight per 100 parts by weight of the varnish.

The conditions for mixing the varnish and the aqueous phase are not particularly limited. For example, the mixing conditions are such that the aqueous phase is added while stirring the varnish at a rotational speed of 4,000 rpm at room temperature and normal pressure. Mixing can be carried out using a homodisper (Labolution, manufactured by Primix Co., Ltd.).

-Second emulsification step The second emulsification step is a step of micronizing the oil-in-water emulsion.

Micronization can be carried out using a high pressure emulsifier (Panda Plus 2000, GEA Niro Soavi) by applying 5 passes of 500 bar pressure.

-Solvent removal process The solvent removal process is a process of distilling off the solvent by distillation under reduced pressure. Vacuum distillation can be performed using conventional, known equipment (diaphragm pumps, etc.).

An emulsion is obtained through the above steps. The resulting emulsion contains a solvent-soluble resin with an SP value of 8-10. The solvent-soluble resin having an SP value of 8 to 10 may be waste plastic or the like. Therefore, emulsions can contribute to solving environmental problems and the like.

Further, the emulsion obtained by the forced emulsification method of the present embodiment can have an average particle size in the range of 0.5 μm to 5 μm. Note that the average particle diameter of the emulsion can be measured using a particle size distribution analyzer (Microtrac UPA, manufactured by Nikkiso Co., Ltd.). As described above, similar to emulsions prepared using conventional monomers as starting materials, the emulsified state is stable and has properties such as excellent gloss. Emulsions can also exhibit excellent properties even when used as aqueous printing ink compositions.

(Phase inversion emulsification)
When producing an emulsion by phase inversion emulsification, the emulsion production method includes a varnish preparation step in which a varnish is prepared by dissolving a solvent-soluble resin with an SP value of 8 to 10 in a solvent, and a dispersing agent is added to the varnish. a heating step in which the water is added to the heated varnish, an emulsification step in which the water phase is continuously added to the heated varnish to invert the emulsion from an oil phase to a water phase, and the solvent is distilled off under reduced pressure. and a solvent removal step. The dispersant includes a first surfactant and a second surfactant different from the first surfactant. The first surfactant includes a first (ethylene oxide/propylene oxide) block copolymer having an HLB of 14-20. The second surfactant includes a nonionic surfactant with an HLB of 14-20.

- Varnish preparation process The varnish preparation process is a process in which a varnish is prepared by dissolving a solvent-soluble resin having an SP value of 8 to 10 in a solvent. The varnish preparation process is similar to the varnish preparation process described above in connection with forced emulsification.

・Heating process The heating process is a process of adding a dispersant to the varnish and heating it. The dispersant is similar to the dispersant described above in connection with forced emulsification.

The amount of dispersant added to the varnish is not particularly limited. For example, the blending amount of the dispersant is 2 to 20 parts by weight per 100 parts by weight of the varnish.

The conditions for mixing the varnish and the dispersant are not particularly limited. Mixing can be carried out using a homodisper (Labolution, manufactured by Primix Co., Ltd.).

Heating conditions are not particularly limited. For example, the heating condition is a temperature increase rate of 1° C./min while stirring the solution. Heating can be carried out using a mantle heater (GB-3, manufactured by Ohshina Denki Co., Ltd.).

- Emulsification process The emulsification process is a process in which an aqueous phase is continuously added to a heated varnish, thereby inverting the phase of the emulsion from an oil phase to an aqueous phase. Specifically, the aqueous phase is slowly added to the mixture (mixture of varnish and dispersant) heated using the mantle heater while stirring at a rotation speed of 1,000 to 10,000 rpm. . This causes the emulsion to undergo phase inversion from an oil phase to an aqueous phase.

-Solvent removal process The solvent removal process is a process of distilling off the solvent by distillation under reduced pressure. Vacuum distillation can be performed using conventional, known equipment (diaphragm pumps, etc.).

An emulsion is obtained through the above steps. The resulting emulsion contains a solvent-soluble resin with an SP value of 8-10. The solvent-soluble resin having an SP value of 8 to 10 may be waste plastic or the like. Therefore, emulsions can contribute to solving environmental problems and the like.

Further, the emulsion obtained by the phase inversion emulsification method of the present embodiment can have an average particle diameter in the range of 0.1 μm to 2 μm. Note that the average particle diameter of the emulsion can be measured using a particle size distribution analyzer (Microtrac UPA, manufactured by Nikkiso Co., Ltd.). As described above, similar to emulsions prepared using conventional styrene monomers as starting materials, the emulsified state is stable and has properties such as excellent gloss. Furthermore, emulsions can exhibit excellent properties even when used as aqueous printing ink compositions or overprint varnish compositions.

<Aqueous printing ink composition>
The aqueous printing ink composition (hereinafter also referred to as ink composition) of one embodiment of the present invention contains the above emulsion.

(emulsion)
The emulsion is similar to the emulsion described above in connection with emulsion embodiments.

The emulsion contains a solvent-soluble resin with an SP value of 8-10. The solvent-soluble resin having an SP value of 8 to 10 may be waste plastic or the like. Therefore, emulsions can contribute to solving environmental problems and the like. Furthermore, the emulsion is stable in its emulsified state and has properties such as excellent gloss, similar to emulsions prepared using conventional styrene monomers as starting materials. Emulsions can also exhibit excellent properties even when used as aqueous printing ink compositions.

The content of the emulsion is not particularly limited. For example, the content of the emulsion in the ink composition is preferably 5% by mass or more, more preferably 15% by mass or more. Further, the content of the emulsion in the ink composition is preferably 60% by mass or less, and more preferably 50% by mass or less. By keeping the content of the emulsion within the above range, the resulting ink composition has the same density, transparency, scratch resistance, and abrasion resistance as when using an emulsion prepared using conventional monomers as starting materials. , has excellent properties such as water friction resistance and blocking resistance.

(Other ingredients)
In addition to the emulsion described above, the ink composition may also contain other components that can be commonly used in the field of aqueous printing ink compositions. Other components include, for example, a colorant, a resin for dispersing pigments, an aqueous medium, and various optional components.

- Coloring agent The coloring agent is not particularly limited. For example, the coloring agent may be an inorganic pigment, and examples include titanium oxide, red iron oxide, antimony red, cadmium yellow, cobalt blue, deep blue, ultramarine, carbon black, and graphite. Further, the colorant may be an organic pigment, and examples thereof include soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, and condensed polycyclic pigments.

When a colorant is blended, the content of the colorant is not particularly limited. For example, the content of the colorant in the ink composition is preferably 3% by mass or more, more preferably 6% by mass or more. Further, the content of the colorant in the ink composition is preferably 60% by mass or less, and more preferably 35% by mass or less. When the content of the colorant is within the above range, the resulting ink composition can easily produce printed matter with a desired print density, has an appropriate viscosity, and is excellent in handleability.

- Pigment dispersion resin The pigment dispersion resin is not particularly limited. For example, the pigment dispersing resin is an alkali-soluble resin.

The alkali-soluble resin is not particularly limited. For example, examples of the alkali-soluble resin include acrylic copolymer resins, maleic acid copolymer resins, polyester resins obtained by condensation polymerization reactions, and polyurethane resins. Examples of materials for synthesizing these alkali-soluble resins include those disclosed in JP-A No. 2000-94825.

Acrylic copolymer resins are prepared by adding a mixture of anionic group-containing monomers and other copolymerizable monomers to a common radical generator (e.g., benzoyl peroxide, tert-butyl peroxybenzoate, azobisisobutylene). lonitrile, etc.) in a solvent.

The anionic group-containing monomer is a monomer having at least one anionic group selected from the group consisting of a carboxyl group, a sulfonic acid group, and a phosphonic acid group.

Monomers having a carboxyl group include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, 2-carboxyethyl (meth)acrylate, 2-carboxypropyl (meth)acrylate, maleic anhydride, and anhydride. These include fumaric acid and maleic acid half ester. Monomers having sulfonic acid groups include sulfoethyl methacrylate. Monomers having phosphonic acid groups include phosphonoethyl methacrylate.

The other monomer copolymerizable with the anionic group-containing monomer preferably includes a hydrophobic group-containing monomer from the viewpoint of improving adsorption with the pigment. Hydrophobic group-containing monomers include alkyl esters of radically polymerizable unsaturated carboxylic acids such as (meth)acrylic acid having 8 or more carbon atoms (for example, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, 2-hydroxystearyl (meth)acrylate, etc.), alkyl vinyl ethers having 8 or more carbon atoms (for example, dodecyl vinyl ether, etc.) , vinyl esters of fatty acids having 8 or more carbon atoms (e.g., vinyl 2-ethylhexanoate, vinyl laurate, vinyl stearate, etc.); As a monomer having an alicyclic hydrocarbon group, cyclohexyl (meth) Acrylate, etc. Monomers having an aromatic hydrocarbon group include benzyl (meth)acrylate, styrene monomers such as styrene, α-methylstyrene, and vinyltoluene.

The other monomer copolymerizable with the anionic group-containing monomer preferably includes a hydrophilic group-containing monomer from the viewpoint of suppressing aggregation of the alkali-soluble resin in an aqueous medium.

Hydrophilic group-containing monomers include monomers having (poly)oxyalkylene chains such as methoxypolyethylene glycol, methoxypolyethylenepolypropylene glycol, ethoxypolyethylene glycol, ethoxypolyethylenepolypropylene glycol, propoxypolyethylene glycol, propoxypolyethylenepolypropylene glycol, etc. Esterified products of (poly)alkylene glycol with one end alkyl-blocked and radically polymerizable unsaturated carboxylic acids such as (meth)acrylic acid, ethylene oxide adducts to radically polymerizable unsaturated carboxylic acids such as (meth)acrylic acid, and / or propylene oxide adducts; examples of basic group-containing monomers include vinylpyrrolidones such as 1-vinyl-2-pyrrolidone and 1-vinyl-3-pyrrolidone, 2-vinylpyridine, 4-vinylpyridine, Vinylpyridines such as 5-methyl-2-vinylpyridine and 5-ethyl-2-vinylpyridine, vinylimidazoles such as 1-vinylimidazole and 1-vinyl-2-methylimidazole, 3-vinylpiperidine, N-methyl Vinyl biperidines such as -3-vinylpiperidine, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, tert-butylaminoethyl (meth)acrylate, (meth)acrylamide, N-methylol (meth)acrylamide, N - Nitrogen-containing derivatives of (meth)acrylic acid such as butoxymethyl (meth)acrylamide, N-methoxy (meth)acrylamide, N-ethoxy (meth)acrylamide, N-dimethylacrylamide, N-propylacrylamide, etc.; having a hydroxyl group Monomers such as hydroxyalkyl esters of (meth)acrylic acid such as hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate; monomers having epoxy groups such as glycidyl (meth)acrylate etc.

Other copolymerizable monomers other than the hydrophobic group-containing monomer and the hydrophilic group-containing monomer include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, These include alkyl esters of (meth)acrylic acid having less than 8 carbon atoms, such as isopropyl (meth)acrylate, butyl (meth)acrylate, and hexyl (meth)acrylate.

When a pigment dispersant is blended, the content of the pigment dispersant is not particularly limited. For example, the content of the pigment dispersant in the ink composition is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more. Further, the content of the pigment dispersant in the ink composition is preferably 10% by mass or less, and more preferably 5% by mass or less. When the content of the pigment dispersant is within the above range, the obtained ink composition has an excellent balance between gloss and water resistance of the coating film.

-Aqueous medium In addition to water, the ink composition of the present embodiment may contain other aqueous media as long as the performance of the ink composition is not deteriorated. The aqueous medium is not particularly limited. By way of example, aqueous media include methanol, ethanol, propanol, butanol, hexanol, octanol, decanol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol Monooctyl ether, diethylene glycol, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, Propylene glycol, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether , tripropylene glycol, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monopropyl ether, tripropylene glycol monobutyl ether, dibutyl glycol, glycerin, and other alcohols and polyhydric alcohol organic solvents.

When an aqueous medium is blended, the content of the aqueous medium is not particularly limited. For example, the content of the aqueous medium in the ink composition is preferably 0.5% by mass or more, and more preferably 1% by mass or more. Further, the content of the aqueous medium in the ink composition is preferably 10% by mass or less, more preferably 5% by mass or less. When the content of the aqueous medium is within the above range, the resulting ink composition has an excellent balance between cleaning properties and drying properties.

- Additives Various additives may be added to the ink composition as necessary. Additives are not particularly limited. For example, additives include extender pigments such as calcium carbonate, kaolin, barium sulfate, aluminum hydroxide, clay, and talc, inorganic fine particles and adhesive resins (acrylic resin, vinyl acetate resin, etc.) to provide anti-slip properties. ), leveling agents to improve leveling properties, antifoaming agents to impart defoaming properties, basic compounds such as caustic soda to impart resolubility, and various additives such as film-forming emulsions.

<Method for producing aqueous printing ink composition>
Ink compositions can be made by conventional methods. For example, the ink composition is prepared by mixing a colorant, a pigment dispersion resin, and a water-containing solvent, and then using various kneading machines such as bead mills, pearl mills, sand mills, ball mills, attritors, and roll mills. It can be produced by kneading the raw material and then mixing materials such as an emulsion and optional additives. The ink composition may be diluted with a solvent containing water, if necessary.

The obtained ink composition can be used for printing on the surface of paper or resin, especially paper containers such as paper cups and paper plates, paper containers whose surfaces are coated with a resin layer, and thin paper for food packages. Alternatively, it can be used by printing on those materials using various printing machines.

<Overprint varnish composition>
An overprint varnish composition (hereinafter also referred to as varnish composition) of one embodiment of the present invention contains the above emulsion.

(emulsion)
The emulsion is similar to the emulsion described above in connection with emulsion embodiments.

The emulsion contains a solvent-soluble resin with an SP value of 8-10. The solvent-soluble resin having an SP value of 8 to 10 may be waste plastic or the like. Therefore, emulsions can contribute to solving environmental problems and the like. Further, the emulsion has a stable emulsion state and has properties such as excellent gloss, similar to emulsions prepared using conventional monomers as starting materials. Moreover, the emulsion can exhibit properties such as excellent gloss and scratch resistance even when used as an overprint varnish composition.

The content of the emulsion is not particularly limited. For example, the content of the emulsion in the varnish composition is preferably 5% by mass or more, more preferably 20% by mass or more. Further, the content of the emulsion in the varnish composition is preferably 90% by mass or less, more preferably 70% by mass or less. By keeping the content of the emulsion within the above range, the resulting varnish composition has excellent properties such as printability and coating resistance, similar to when using conventional emulsions prepared using styrene monomer as a starting material. .

(Other ingredients)
In addition to the emulsion described above, the varnish composition may also contain other components that can be commonly used in the field of overprint varnish compositions. Other components include, for example, an aqueous resin, an aqueous medium, and various optional components.

- Water-based resin The water-based resin is not particularly limited. Examples include alkali-soluble resins and emulsion-type aqueous resins. Alkali-soluble resins are similar to those described above in connection with aqueous printing ink compositions. Specifically, emulsion type water-based resins include styrene-acrylic water-based resins, styrene-maleic acid-based water-based resins, styrene-acrylic-maleic acid-based water-based resins, etc. obtained by emulsion polymerization using a polymer emulsifier. be.

The polymer emulsifier includes a carboxyl group-containing α,β-monoethylenically unsaturated monomer, an ethylenically unsaturated monomer A having a highly hydrophobic aromatic ring, and other copolymerizable monomers as necessary. These are copolymer resins with an acid value of 100 to 200 mgKOH/g obtained by copolymerizing ethylenically unsaturated monomers.

The carboxyl group-containing α,β-monoethylenically unsaturated monomers include (meth)acrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic anhydride, maleic acid, and maleic acid monoester.

Examples of the ethylenically unsaturated monomer A having an aromatic ring include styrene monomers such as styrene, α-methylstyrene, vinyltoluene, and derivatives thereof, benzyl (meth)acrylate, and naphthyl (meth)acrylate. etc.

Other copolymerizable ethylenically unsaturated monomers include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate. , hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, 2-hydroxystearyl (meth)acrylate, and the like.

The acid value of the polymer emulsifier is preferably 100 to 200 mgKOH/g, more preferably 150 to 200 mgKOH/g. If the acid value is less than 100 mgKOH/g, the solubility of the polymer emulsifier in water may decrease. On the other hand, if the acid value exceeds 200 mgKOH/g, the resulting printed matter may have reduced water resistance.

Basic compounds used to dissolve or disperse the polymer emulsifier in water include ammonia, organic amines, alkali metal hydroxides, and the like. Specifically, the organic amine is an alkylamine such as diethylamine, triethylamine, or ethylenediamine, or an alkanolamine such as monoethanolamine, ethylethanolamine, diethylethanolamine, diethanolamine, or triethanolamine. Alkali metal hydroxides include sodium hydroxide, potassium hydroxide, and the like. Among these, the basic compound is preferably one that easily evaporates at room temperature or with slight heating in order to improve drying properties.

-Aqueous Medium In addition to water, the varnish composition of the present embodiment may contain other aqueous media as long as the performance of the varnish composition is not deteriorated. As the aqueous medium, the same one used for the ink composition can be used.

When an aqueous medium is blended, the content of the aqueous medium is not particularly limited. For example, the content of the aqueous medium in the varnish composition is preferably 0.5% by mass or more, more preferably 1% by mass or more. Further, the content of the aqueous medium in the ink composition is preferably 10% by mass or less, more preferably 5% by mass or less. When the content of the aqueous medium is within the above range, the resulting varnish composition has an excellent balance between cleaning properties and drying properties.

-Additives Various additives may be added to the varnish composition as necessary. Additives are not particularly limited. For example, additives include extender pigments such as calcium carbonate, kaolin, barium sulfate, aluminum hydroxide, clay, and talc, inorganic fine particles and adhesive resins (acrylic resin, vinyl acetate resin, etc.) to provide anti-slip properties. ), leveling agents to improve leveling properties, antifoaming agents to impart defoaming properties, basic compounds such as caustic soda to impart resolubility, and various additives such as film-forming emulsions.

<Method for manufacturing varnish composition>
The varnish composition may be made by conventional methods. For example, a varnish composition can be prepared by mixing and stirring an emulsion, each of the above-mentioned materials, and any additives. The varnish composition may be diluted with a water-containing solvent if necessary.

The obtained varnish composition can be used for printing on the surface of paper or resin, especially paper containers such as paper cups and paper plates, paper containers whose surfaces are coated with a resin layer, and thin paper for food packages. Alternatively, it can be used by printing on those materials using various printing machines.

Hereinafter, the present invention will be explained in more detail with reference to Examples. The present invention is not limited to these Examples in any way. In addition, unless otherwise specified, "%" means "% by mass" and "parts" means "parts by mass."

The raw materials and preparation method used are shown below.
Polystyrene: GPPS (HF77 306), manufactured by PS Japan Co., Ltd., general grade Polymethyl methacrylate: Acrypet VH 001, manufactured by Mitsubishi Chemical Corporation Methyl methacrylate-styrene copolymer: Cevian MAS10, Daicel Millize Co., Ltd. Manufactured by Polycarbonate: Iupizeta FPC-2136, manufactured by Mitsubishi Gas Chemical Co., Ltd. Waste polymethyl methacrylate: Factory scraps (cuttings)
Waste methyl methacrylate-styrene copolymer: Factory scraps (chips)
Rosin ester: Ester Gum AAG, manufactured by Arakawa Chemical Industry Co., Ltd., acid value 0.1-7
Maleic acid modified rosin ester: Marquid No. 2. Manufactured by Arakawa Chemical Industry Co., Ltd., acid value 39 or less Polymerized rosin: Aradime R-95, manufactured by Arakawa Chemical Industry Co., Ltd., acid value 158-168
Fumaric acid modified rosin ester: Neosite F-896, manufactured by Kusumoto Kasei Co., Ltd., acid value 205
EO/PO block copolymer 1: ADEKA Pluronic F-108, manufactured by ADEKA Co., Ltd., HLB: 15.8, weight average molecular weight: 19,000
EO/PO block copolymer 2: ADEKA Pluronic F-68, manufactured by ADEKA Co., Ltd., HLB: 16.0 EO/PO block copolymer 3: Newpol PE-78, manufactured by Sanyo Chemical Industries, Ltd., HLB :15.6
EO/PO block copolymer 4: ADEKA Pluronic L-121, manufactured by ADEKA Co., Ltd., HLB: 5.1
EO/PO block copolymer 5: ADEKA Pluronic L-64, manufactured by ADEKA Co., Ltd., HLB: 12.5
Polyoxyethylene alkyl ether 1: Emulgen 350, manufactured by Kao Corporation, HLB: 17.8
Polyoxyethylene alkyl ether 2: Emanone 3199VB, manufactured by Kao Corporation, HLB: 19.4
Polyoxyethylene alkyl ether 3: Rheodol TW120L, manufactured by Kao Corporation, HLB: 16.7
Polyoxyethylene alkyl ether 4: Rheodol TW120O, manufactured by Kao Corporation, HLB: 15.0
Polyoxyethylene alkyl ether 5: Emanone CH-60, manufactured by Kao Corporation, HLB: 14.0
Polyoxyethylene alkyl ether 6: Emulgen 306P, manufactured by Kao Corporation, HLB: 9.4
Polyoxyethylene alkyl phenyl ether 1: Emulsogen TS600, manufactured by Clariant, HLB: 17.5
Polyoxyethylene alkyl phenyl ether 2: Emulsogen TS200, manufactured by Clariant, HLB: 14.0
Polyoxyethylene alkyl phenyl ether 3: Emulgen B66, manufactured by Kao Corporation, HLB: 13.2
Polyglycerin fatty acid ester 1: MCA-7S, manufactured by Sakamoto Pharmaceutical Co., Ltd., HLB: 16.1
Polyglycerin fatty acid ester 2: M-7S, manufactured by Sakamoto Pharmaceutical Co., Ltd., HLB: 12.9
Styrene maleic acid: Hyros X-200, manufactured by Seiko PMC Co., Ltd., acid value 190
Styrene acrylic emulsion: Joncryl 778, manufactured by BASF, styrene-based core-shell emulsion

<Example 1>
Polystyrene varnish was prepared by dissolving 35.7 parts by mass of polystyrene in 102 parts by mass of a solvent (ethyl acetate) (varnish preparation step). Next, 137.7 parts by mass of polystyrene varnish was added to 119 parts by mass of an aqueous phase containing 3.4 parts by mass of EO/PO block copolymer 1 and 3.4 parts by mass of EO/PO block copolymer 2. were mixed and stirred for 10 minutes at a rotation speed of 4,000 rpm to produce an oil-in-water emulsion (first emulsification step). Next, the oil-in-water emulsion was micronized by 5 passes at a pressure of 500 bar using a high-pressure emulsifier (Panda Plus 2000, GEA Niro Soavi) (second emulsification step). Thereafter, the solvent was distilled off under reduced pressure using a diaphragm pump while stirring at a temperature below 50°C. The polystyrene emulsion of Example 1 had the formulation shown in Table 1.

<Examples 2 to 7, Comparative Examples 1 to 5>
An emulsion was prepared in the same manner as in Example 1, except for changing the formulation as shown in Tables 1 and 2.

<Example 8>
Polystyrene varnish was prepared by dissolving 28.9 parts by mass of polystyrene in 102 parts by mass of a solvent (ethyl acetate) (varnish preparation step). Next, 3.4 parts by mass of EO/PO block copolymer 1, 3.4 parts by mass of EO/PO block copolymer 2, 8.5 parts by mass of styrene maleic acid, and 6.8 parts by mass. of polymerized rosin was added, and the solution was heated to 50°C at a temperature increase rate of 1°C/min using a mantle heater while stirring the solution (heating step). Next, 119 parts by mass of an aqueous phase containing 0.6 parts by mass of ammonia was added to the above solution at a rate of 7 parts by mass/min while stirring at a rotational speed of 4,000 rpm to emulsify the solution (emulsification step). Thereafter, the solvent was distilled off under reduced pressure using a diaphragm pump while stirring at a temperature below 50°C. The polystyrene emulsion of Example 8 had the formulation shown in Table 1.

<Examples 9 to 28, Comparative Examples 6 to 8>
An emulsion was prepared in the same manner as in Example 8, except that the formulations were changed as shown in Tables 1 to 3. However, the solvents used in Examples 24 to 28 were methyl ethyl ketone, ethyl acetate, ethyl acetate, methyl ethyl ketone, and ethyl acetate, respectively.

<Reference example 1>
A commercially available product, Joncryl 778 (manufactured by BASF, a styrene-acrylic emulsion having a core-shell structure), was evaluated.

The emulsions of Examples, Comparative Examples, and Reference Examples obtained above were evaluated for emulsion state, storage stability, average particle diameter (μm), gloss, transparency, and scratch resistance according to the following evaluation methods. In addition, water-based printing ink compositions were prepared for the emulsions of Examples, Comparative Examples, and Reference Examples obtained above according to the following evaluation methods, and Friction properties and blocking resistance were evaluated. The results are shown in Table 1 or Table 2.

<Evaluation of emulsion>
(emulsified state)
During production of the emulsion, the state after mixing the aqueous phase and oil phase was visually observed and evaluated according to the following evaluation criteria.
○: The mixed aqueous phase and oil phase stably maintained a milky white suspended state.
Δ: The mixed aqueous phase and oil phase were slightly separated.
×: The mixed aqueous phase and oil phase were separated into two layers.
(Storage stability)
The emulsion was placed in a sealed sample bottle, and the viscosity change rate before and after static storage at 40° C. for one week was calculated using the following formula (1), and evaluated according to the following evaluation criteria.
Viscosity change rate = (viscosity after storage - viscosity before storage) / viscosity before storage x 100 (1)
○: The absolute value of the viscosity change rate was less than 50%.
Δ: The absolute value of the viscosity change rate was 50% or more and less than 100%, or the sample after storage showed slight separation or sedimentation.
×: The absolute value of the viscosity change rate was 100% or more, or significant separation, sedimentation, solidification, and gelation were observed in the sample after storage.
(Average particle size)
The average particle diameter was measured by dynamic light scattering using a Microtrack UPA particle size distribution analyzer (manufactured by Nikkiso Co., Ltd.).
(glossy)
The emulsion was spread on an OPP film using a 0.15 mm mesh bar, and the state of the reflected light when the light generated from the fluorescent lamp bounced off the spread material was visually observed, and according to the following evaluation criteria. evaluated. The aqueous varnish compositions described below were also evaluated in the same manner.
○: The reflected light could be observed clearly without becoming hazy.
Δ: The reflected light was slightly hazy.
×: Reflected light could not be observed.
(transparency)
The emulsion was spread on an OPP film using a 0.15 mm mesh bar, and the state of the transmitted light was visually observed when light from a fluorescent lamp was passed through the film spread, and evaluated according to the following evaluation criteria. did.
○: Transmitted light could be observed clearly without becoming hazy.
Δ: Transmitted light was slightly hazy.
×: Transmitted light could not be observed.
(Scratch resistance)
The emulsion was spread on an OPP film using a 0.15 mm mesh bar, and when the paint film was rubbed with a fingernail, the degree of shedding of the paint film was visually observed and evaluated according to the following evaluation criteria.
○: The coating film did not fall off.
Δ: The coating film slightly fell off.
×: The coating film fell off.

<Evaluation of water-based printing ink composition>
・Preparation of base ink According to the following recipe, pigment (phthalocyanine blue, B-15:3), water-soluble resin varnish (Joncryl HPD-671, manufactured by BASF, St-Ac type, solid content 25%), isopropyl alcohol After mixing the water mixture with a bead mill, the remaining materials were added and mixed to prepare the base ink.

Jonkryl HDP-671 (solid content 25%) 25.00
Isopropyl alcohol 2.00
Wednesday 15.00
Pigment (B-15:3) 30.00
↓Beads paste Jonkryl HDP-671 (solid content 25%) 20.00
Wednesday 8.00
100.00 (parts by mass)

(Preparation of water-based printing ink composition)
To 30.0 parts by mass of the base ink prepared above, 1.5 parts by mass of Chemipearl W100 (polyethylene wax manufactured by Mitsui Chemicals, Inc.) and Surfynol 104E (acetylene diol-based surfactant manufactured by Nissin Chemical Industries, Ltd.) ), 0.03 parts by mass of S N Deformer 777 (antifoaming agent manufactured by San Nopco Co., Ltd.), and the emulsions of Examples 8 to 11, 14 to 28 and Comparative Examples 6 to 8, with a solid content of After mixing in an amount of 20%, water was added so that the total amount was 100 parts by mass, and the mixture was stirred and mixed to prepare an aqueous printing ink composition.

(Preparation of water-based varnish composition)
The emulsions of Examples 8 to 11, 14 to 28 and Comparative Examples 6 to 8 were mixed with 1.5 parts by mass of Chemipearl W100 (polyethylene wax manufactured by Mitsui Chemicals, Inc.) and Surfi in an amount such that the solid content was 29% by mass. After mixing 0.3 parts by mass of Norl 104E (acetylene diol surfactant manufactured by Nissin Chemical Co., Ltd.) and 0.03 parts by mass of SN Deformer 777 (defoaming agent manufactured by San Nopco Co., Ltd.), the total amount was Water was added to make 100 parts by mass, and the mixture was stirred and mixed to prepare an aqueous varnish composition.

(concentration)
The aqueous printing ink composition was spread on a K liner (manufactured by Oji Paper Co., Ltd.) using a spatula, and the OD value was measured three times using a spectrophotometer (eXact, manufactured by X-Rite Co., Ltd.). The average value was evaluated according to the following evaluation criteria.
○: OD value was 1.5 or more.
Δ: OD value was 1.4 or more and less than 1.5.
x: OD value was less than 1.4.
(transparency)
The water-based printing ink composition was spread on an OPP film using a 0.15 mm mesh bar, and the state of the transmitted light when the film-spread colored object was irradiated with light was visually observed and evaluated according to the following evaluation criteria. did. Aqueous varnish compositions were also evaluated in the same manner.
○: Transmitted light could be observed clearly without becoming hazy.
Δ: Transmitted light was slightly hazy.
×: Transmitted light could not be observed.
(Scratch resistance)
The adhesive layer side of an adhesive sheet (Cello Tape (registered trademark)) manufactured by Nichiban Co., Ltd. is pasted on the surface of each printed matter in which the water-based printing ink composition has been spread on an OPP film using a 0.15 mm mesh bar. , a peeling operation was performed, and evaluation was made according to the following evaluation criteria.
○: The coating film did not peel off. Aqueous varnish compositions were also evaluated in the same manner.
Δ: Part of the coating film peeled off.
×: Most of the coating film was peeled off.
(Abrasion resistance)
Each printed matter, in which the aqueous printing ink composition was spread on a K liner (manufactured by Oji Paper Co., Ltd.) using a 0.15 mm mare bar, was cut into 2.5 cm x 25 cm as a test piece. Using a friction tester (manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.), apply the plain surface of the K-liner to the printed surface of the printed matter and rub it 100 times with a load of 500 g, according to the following evaluation criteria. evaluated. Aqueous varnish compositions were also evaluated in the same manner.
○: In the printed matter, no falling off of the printed surface or contamination of the plain surface was observed.
△: In the printed matter, slight falling off of the printed surface and contamination of the plain surface were observed.
×: In the printed matter, falling off of the printed surface and contamination of the plain surface were observed.
(Water resistance and abrasion resistance)
Each printed matter, in which the aqueous printing ink composition was spread on a K liner (manufactured by Oji Paper Co., Ltd.) using a 0.15 mm mare bar, was cut into 2.5 cm x 25 cm as a test piece. Using a friction tester (manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.), a bleached cloth with 5 drops of water applied to the printed surface of the printed matter was rubbed twice with a load of 200 g, and the following evaluations were made. Evaluation was made according to the criteria. Aqueous varnish compositions were also evaluated in the same manner.
○: In the printed matter, no falling off of the printed surface or staining of the bleached cloth was observed.
△: In the printed matter, slight falling off of the printed surface and staining of the bleached cloth were observed.
×: In the printed matter, falling off of the printed surface and staining of the bleached cloth were observed.
(blocking resistance)
A load of 1 kg/cm ² was applied to two prints of each type, in which the water-based printing ink composition was spread on K liner (manufactured by Oji Paper Co., Ltd.) using a 0.15 mm mare bar, and the printed surfaces were combined. After being left at 40° C. and 90% RH for 24 hours, it was peeled off by hand and evaluated according to the following evaluation criteria. Aqueous varnish compositions were also evaluated in the same manner.
Good: In the printed matter, the printed surfaces were easily peeled off, and no peeling of the printed surfaces was observed.
△: In the printed matter, the printed surfaces were slightly adhered to each other, and slight falling off of the printed surfaces was observed.
×: In the printed matter, the printed surfaces were strongly adhered to each other, and some of the printed surfaces were observed to fall off.

As described in Tables 1 to 3, the emulsion of the present invention can use a solvent-soluble resin having an SP value of 8 to 10 as a starting material, has a stable emulsified state, and has good storage stability. Excellent properties such as gloss and gloss. Further, the ink composition containing the emulsion of the present invention had excellent properties such as density, transparency, scratch resistance, abrasion resistance, water abrasion resistance, and blocking resistance. Furthermore, the aqueous varnish composition containing the emulsion of the present invention has excellent properties such as gloss, transparency, scratch resistance, abrasion resistance, water abrasion resistance, and blocking resistance.

Claims (8)

It has a core-shell structure having a core part and a shell part,
The core portion includes a resin soluble in a solvent having an SP value of 8 to 10,
The shell portion includes a first surfactant and a second surfactant different from the first surfactant,
The first surfactant includes a first (ethylene oxide/propylene oxide) block copolymer having an HLB of 14 to 20,
The second surfactant is an emulsion containing a nonionic surfactant having an HLB of 14 to 20. The resin soluble in a solvent having an SP value of 8 to 10 is polystyrene, polymethyl methacrylate, polycarbonate, polyurethane, methyl methacrylate-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, or polyester. 2. The emulsion according to claim 1, comprising at least one of . The second surfactant is at least one selected from the group consisting of (ethylene oxide/propylene oxide) block copolymer having an HLB of 14 to 20, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, or polyglycerin fatty acid ester. The emulsion according to claim 1 or 2, comprising: The emulsion according to claim 1 or 2, wherein the shell portion contains at least one of styrene-maleic acid and rosin. An aqueous printing ink composition comprising an emulsion according to claim 1 or 2. An overprint varnish composition comprising an emulsion according to claim 1 or 2. A varnish preparation step of preparing a varnish by dissolving a resin soluble in a solvent having an SP value of 8 to 10 in the solvent;
A first emulsification step of mixing the varnish with an aqueous phase containing a dispersant to create an oil-in-water emulsion;
a second emulsification step of making the oil-in-water emulsion fine;
a solvent removal step of distilling off the solvent by distillation under reduced pressure,
The dispersant includes a first surfactant and a second surfactant different from the first surfactant,
The first surfactant includes a first (ethylene oxide/propylene oxide) block copolymer having an HLB of 14 to 20,
The method for producing an emulsion, wherein the second surfactant includes a nonionic surfactant having an HLB of 14 to 20. A varnish preparation step of preparing a varnish by dissolving a resin soluble in a solvent having an SP value of 8 to 10 in the solvent;
a heating step of adding a dispersant to the varnish and heating it;
an emulsification step of continuously adding an aqueous phase to the heated varnish and inverting the emulsion from an oil phase to an aqueous phase;
a solvent removal step of distilling off the solvent by distillation under reduced pressure,
The dispersant includes a first surfactant and a second surfactant different from the first surfactant,
The first surfactant includes a first (ethylene oxide/propylene oxide) block copolymer having an HLB of 14 to 20,
The method for producing an emulsion, wherein the second surfactant includes a nonionic surfactant having an HLB of 14 to 20.