KR101669425B1 - Starch-based polymer particle emulsion and manufacturing method thereof - Google Patents

Abstract

The present invention provides a starch-based polymer particle emulsion comprising starch-based polymer particles as a dispersion medium and water as a dispersion medium. The starch-based polymer particles have a core-shell structure including a core formed by polymerization of a starch decomposition product and a core-forming monomer, and a shell formed on the core by polymerization of a shell-forming monomer. The starch-based polymer particle emulsion according to the present invention is based on starch, which is biomass capable of repeated production, and is eco-friendly as compared with emulsions for metal-based coatings based on conventional petroleum raw materials and stable in raw material supply, Can be secured. Further, since the starch-based polymer particle emulsion according to the present invention can form a coating film having excellent adhesion to the surface of the metal substrate and at the same time, the phenomenon of sticking to each other between the coating films can be minimized, It can be used as a coating material or a coating material for forming a layer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a starch-based polymer emulsion and a manufacturing method thereof,

The present invention relates to a starch-based polymer particle emulsion and a method for producing the same, and more particularly to a starch-based polymer particle emulsion containing a starch-based polymer particle having a core-shell structure as a dispersion medium and a combination of monomers forming a core and a combination of monomers forming a shell To a method for producing the same using a combination of a starch-based polymer particle emulsion and a specific emulsifier capable of forming a coating film having a strong adhesive force on the surface of a metal substrate and minimizing the phenomenon of sticking to each other.

Coatings are commonly used to impart aesthetics to the surface of building materials or metallic materials, but they are now mainly used to protect the surface of building materials or metallic materials from external factors such as water, dust, air, oil and the like. For example, a steel sheet having a plated layer composed of a mixture of zinc, nickel, aluminum, and silica or a single composition maintains a high-quality appearance, but contamination due to fingerprints may easily occur, there is a problem. Therefore, an organic resin such as a water-dispersible acrylic resin, a water-dispersible epoxy resin, and a water-dispersible urethane resin is applied to the surface of a metal such as a zinc alloy plated steel sheet or an aluminum alloy steel sheet to form a coating film having a certain thickness, Efforts to improve the quality of life are continuing. In this connection, Korean Patent Registration No. 10-0774957 (Prior Art 1) discloses that 38 to 60% by weight of a water-soluble urethane acrylic hybrid resin; 1 to 3% by weight of an additive comprising antifoaming agents, wetting agents and rust inhibitors; Wherein the water-soluble urethane acrylic hybrid resin comprises 40 to 70 parts by weight of a water-soluble urethane dispersion and 30 to 40 parts by weight of an acrylic monomer containing an acetoacetoxy monomer in the presence of an acrylic reaction initiator Disclosed is a water-dispersed urethane acrylic hybrid coating for metal coating.

On the other hand, conventional metal-based coatings are made of petrochemical raw materials, which causes a problem of low environmental friendliness. To solve this problem, coating materials using natural raw materials have been studied. In particular, starch has attracted much attention as an eco-friendly coating material because it has good adhesiveness, low cost, and excellent heat resistance. In this connection, Korean Patent Registration No. 10-1473916 (Prior Art 2) discloses an aqueous emulsion for a paint containing dispersed, starch-based polymer particles and water as a dispersion medium. The starch-based polymer particles disclosed in the above-mentioned Reference 2 include a core made of a starch-based copolymer formed by polymerization of a starch-decomposed material and a core monomer mixture comprising a hard monomer and a soft monomer; And a shell formed of a copolymer formed on the core by polymerization of a shell monomer mixture comprising a hard monomer, a soft monomer, and a silane-based unsaturated monomer, wherein the hard monomer is a core- Wherein the soft monomer has an ethylenic unsaturated bond and the glass transition temperature of the homopolymer is 10 ° C to -80 ° C, and the glass transition temperature of the homopolymer is 30 ° C to 250 ° C. The silane-based unsaturated monomer includes at least one silane skeleton and at least one unsaturated bonding functional group capable of polymerizing with a hard monomer or a soft monomer. However, when a coating film is formed by applying the aqueous emulsion for coating to the surface of a metal substrate disclosed in the above-mentioned prior art document 2, the adhesion of the coating film is excellent but the coating films stick together. Particularly, when a plurality of metal sheets are laminated and stored for a long period of time, when the coated films formed on the surface of the metal sheet are stuck to each other, there is a problem that the coating film is damaged or the operation is delayed in the process of separating the metal sheet.

It is an object of the present invention to provide a starch-based polymer particle emulsion which can form a coating film having excellent adhesion to the surface of a metal substrate and can minimize the phenomenon of sticking to each other between coating films, And a method for producing the same.

The inventors of the present invention have found that when preparing starch-based polymer particles of core-shell structure by water-based emulsion polymerization, the type and content relationship of the monomers forming the core and the type and content relationship of the monomers forming the shell are controlled, It has been confirmed that the final emulsion can form a coating film having excellent adhesion to the surface of the metal substrate and the phenomenon of sticking to each other between the coating films hardly occurs when the types of emulsifiers are combined in the step or shell- Completed.

In order to solve the above object, an example of the present invention is an aqueous emulsion comprising water as dispersion medium and starch-based polymer particles and dispersion medium, wherein the starch-based polymer particles are a core and a shell formed by polymerization of a starch- Wherein the core forming monomer comprises a hard monomer, a soft monomer and a carboxylic acid monomer having an ethylenically unsaturated bond, wherein the core forming monomer comprises a shell-forming monomer Starch polymer particle emulsion comprising a hard monomer, a soft monomer, a carboxylic acid monomer having an ethylenically unsaturated bond, a chain transfer agent and a reactive emulsifier. The hard monomer has an ethylenic unsaturated bond and the homopolymer has a glass transition temperature of 30 ° C to 250 ° C. The soft monomer has an ethylenic unsaturated bond and the glass transition temperature of the homopolymer is 10 ° C To -80 < 0 > C. Also, the reactive emulsifier may be selected from the group consisting of a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a propenyl group, a vinylidene group And at least one functional group selected from a vinylene group. Also, the content of the soft monomer in the core-forming monomer is 80 to 92% by weight, and the content of the hard monomer in the shell-forming monomer is 70 to 82% by weight.

Another object of the present invention is to add an anionic emulsifier to a starch liquefied liquid containing a starch hydrolyzate and to mix it with a core-forming monomer and a polymerization initiator, Obtaining an aqueous emulsion; And a step of adding a shell-forming monomer and a polymerization initiator to an aqueous emulsion containing the core and polymerizing to form a shell on the core. The present invention also provides a method for producing a starch-based polymer particle emulsion. Wherein the core-forming monomer comprises a hard monomer, a soft monomer and a carboxylic acid monomer having an ethylenically unsaturated bond, wherein the shell-forming monomer is selected from the group consisting of a hard monomer, a soft monomer, a carboxylic acid monomer having an ethylenically unsaturated bond, The emulsions include reactive and reactive emulsifiers. The hard monomer has a ethylenically unsaturated bond and the homopolymer thereof has a glass transition temperature of 30 ° C to 250 ° C. The soft monomer has an ethylenically unsaturated bond and the glass transition temperature of the homopolymer is 10 ° C to -80 < 0 > C. Also, the reactive emulsifier may be selected from the group consisting of a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a propenyl group, a vinylidene group And at least one functional group selected from a vinylene group. Also, the content of the soft monomer in the core-forming monomer is 80 to 92% by weight, and the content of the hard monomer in the shell-forming monomer is 70 to 82% by weight.

The starch-based polymer particle emulsion according to the present invention is based on starch, which is biomass capable of repeated production, and is eco-friendly as compared with emulsions for metal-based coatings based on conventional petroleum raw materials and stable in raw material supply, Can be secured. Further, since the starch-based polymer particle emulsion according to the present invention can form a coating film having excellent adhesion to the surface of the metal substrate and at the same time, the phenomenon of sticking to each other between the coating films can be minimized, It can be used as a coating material or a coating material for forming a layer.

Hereinafter, the present invention will be described in detail.

One aspect of the present invention relates to a starch-based polymer particle emulsion that can be used for surface coating of metal substrates. The starch-based polymer particle emulsion according to the present invention is an aqueous emulsion containing starch-based polymer particles as a dispersion medium and water as a dispersion medium. Also, the starch-based polymer particles according to the present invention, which is a dispersion of the starch-based polymer particle emulsion, comprises a core-shell formed by polymerization of a mixture of a starch decomposition product and a core monomer mixture and a shell formed on the core by polymerization of a shell monomer mixture Structure. Hereinafter, the starch-based polymer particles are divided into a core and a shell.

core

In the starch-based polymer particles of the present invention, the core comprises a starch-based copolymer formed by the polymerization of a starch decomposition product and a core-forming monomer.

The starch hydrolyzate is obtained by treating starch with enzyme, acid, heat or the like and decomposing it into a state capable of liquefaction in water. The raw starch for obtaining the starch hydrolyzate includes all natural starches derived from plants, physically or chemically modified starches, and the like. The natural starches may be selected from various plant-derived starches (i.e., unmodified starches) including corn, waxy corn, potatoes, sweet potatoes, wheat, rice, tapioca, sago, waxy maize, sorghum, . In addition, the modified starch includes all the starches obtained by reforming the unmodified starch by methods such as etherification, esterification, oxidation, acid treatment, oxidative esterification, oxidative etherification, enzyme treatment and the like. The starch hydrolyzate used for forming the starch-based polymer particles in the present invention preferably has at least one functional group selected from the group consisting of a carboxyl group, a carbonyl group, an aldehyde group and an ester group from the viewpoint of improving the efficiency of the polymerization reaction, The starch hydrolyzate may be prepared by decomposing at least one modified starch selected from the group consisting of oxidized starch, esterified starch, and oxidized esterified starch, or oxidizing, esterifying, or oxidizing the starch hydrolyzate obtained by decomposing unmodified starch Can be manufactured.

In addition, the core-forming monomer includes a hard monomer, a soft monomer, and a carboxylic acid monomer having an ethylenic unsaturated bond. The term " hard monomer " refers to a monomer containing an ethylenic unsaturated bond such as a vinyl group, an allyl group or an acryl group, and the homopolymer is not tacky at room temperature. In the present invention, the light-weight monomer has such a characteristic, and at the same time, the homopolymer is a monomer having a glass transition temperature of 30 ° C to 250 ° C, preferably 40 ° C to 200 ° C. The type of the hard monomer constituting the core-forming monomer in the present invention is not particularly limited as long as it satisfies the above-mentioned characteristics, and preferable examples thereof include styrene, methyl methacrylate, ethyl methacrylate, butyl methacrylate, acrylonitrile, And may be at least one member selected from the group consisting of methacrylonitrile, isobornyl acrylate, isobornyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, vinyltoluene, vinyl acetate and vinyl chloride, It is more preferable that it is a combination of acrylate and styrene. Also, the soft monomer refers to a monomer containing an ethylenic unsaturated bond such as a vinyl group, an allyl group or an acryl group, and the homopolymer is tacky at room temperature. In the present invention, the soft monomer has such a characteristic, and at the same time, the homopolymer is a monomer having a glass transition temperature of from 10 캜 to -80 캜, preferably from 5 캜 to -60 캜. The type of the soft monomer constituting the core-forming monomer in the present invention is not particularly limited as long as it satisfies the above-mentioned characteristics, and is preferably selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, ethylhexyl acrylate, Acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, and hydroxybutyl acrylate, and a combination of butyl acrylate and ethylhexyl acrylate may be used. desirable. In the present invention, the carboxylic acid monomer having an ethylenically unsaturated bond constituting the core-forming monomer may have an ethylenic unsaturated bond such as a vinyl group, an allyl group or an acrylic group for polymerization with other monomers, And is preferably at least one selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid and fumaric acid, and more preferably acrylic acid or methacrylic acid.

In addition, the content of the soft monomer in the core-forming monomer is preferably 80 to 92% by weight, more preferably 82 to 90% by weight.

The content of the hard monomer in the core-forming monomer is preferably 5 to 20% by weight, more preferably 6 to 15% by weight.

The content of the carboxylic acid monomer having an ethylenically unsaturated bond in the core-forming monomer is preferably 1 to 12% by weight, more preferably 2 to 10% by weight.

The weight ratio of the hard monomer to the soft monomer constituting the core-forming monomer is preferably 1: 6 to 1:15, more preferably 1: 6 to 1:12, and even more preferably 1: 8 to 1:10 Is most preferable.

The weight ratio of the starch decomposed product to the core forming monomer in the core is preferably 1: 0.5 to 1: 3, more preferably 1: 1 to 1: 3, most preferably 1: 1 to 1: desirable.

Shell

In the starch-based polymer particles of the present invention, the shell is composed of a copolymer formed on the core by polymerization of a shell-forming monomer.

The shell-forming monomers include a hard monomer, a soft monomer, a carboxylic acid monomer having an ethylenically unsaturated bond, a chain transfer agent and a reactive emulsifier. In the present invention, the hard monomer constituting the shell-forming monomer includes the content of the hard monomer constituting the core-forming monomer, preferably styrene, methyl methacrylate, ethyl methacrylate, butyl methacrylate, acrylonitrile, And may be at least one member selected from the group consisting of methacrylonitrile, isobornyl acrylate, isobornyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, vinyltoluene, vinyl acetate and vinyl chloride, It is preferable that the combination of acrylate and styrene. In the present invention, the soft monomer constituting the shell-forming monomer includes the content of the soft monomer constituting the core-forming monomer, and preferably includes methyl acrylate, ethyl acrylate, butyl acrylate, ethylhexyl acrylate, Acrylate, hydroxyethyl acrylate, hydroxyethyl acrylate, hydroxyethyl acrylate, hydroxyethyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl acrylate, hydroxyethyl acrylate and hydroxybutyl acrylate. More preferably, it is butyl acrylate. In addition, the carboxylic acid monomer having an ethylenically unsaturated bond constituting the shell-forming monomer in the present invention contains the content of the carboxylic acid monomer having an ethylenically unsaturated bond constituting the core-forming monomer, and preferably, Acrylic acid, acrylic acid, methacrylic acid, itaconic acid, maleic acid and fumaric acid, and more preferably acrylic acid or methacrylic acid. The chain transfer agent constituting the shell-forming monomer in the present invention is not limited in its kind for controlling the molecular weight of the polymer and is preferably n-dodecyl mercaptan, t-dodecyl mercaptan, 1,5-pentane Dithiol, 1,6-hexanedithiol, 2-ethylhexyl-3-mercaptopropionate, butyl 3-mercaptopropionate, dodecyl 3-mercaptopropionate, ethyl 2-mercaptopropionate Methyl 3-mercaptopropionate, pentaerythritol tetrakis (3-mercaptopropionate), 2-ethylhexyl mercaptoacetate, ethyl 2-mercaptoacetate, 2-methyl-2-methyl-1,3-propanediol and pentaerythritol tetrakis (2-mercaptoacetate), and n-dodecyl mercaptan, t- It is more preferable that dodecyl mercaptan is selected. In the present invention, the reactive emulsifier acts as an emulsifier for dispersing the other components evenly in the aqueous phase in the step of preparing the pre-emulsion of the shell-forming monomer described later, and forms a shell by polymerizing with other monomers in the shell forming step. The reactive emulsifier may be selected from the group consisting of a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a propenyl group, The type thereof is not limited as long as it has at least one unsaturated bond functional group selected from a vinylidene group and a vinylene group. Examples of the reactive emulsifier usable in the present invention include ammonium salts of nonyl propenyl ethoxy ether sulfate (Aquaron HS-10 (DKS, Japan), SE-10 (Adeka, Japan) Sulfonic acid esters of polyoxyethylene allylglycidylnonylphenyl ether [commercially available products such as SETM (Adeka, Japan)], sulfonic acid esters of polyoxyethylene nonylphenyl ether sulfate Ammonium salts (HITENOL HSTM (DKS, Japan), etc.), and the like, and these can be used singly or in combination of two or more.

In addition, the content of the hard monomer in the shell-forming monomer is preferably 70 to 82% by weight, more preferably 72 to 80% by weight.

The content of the soft monomer in the shell-forming monomer is preferably 10 to 25% by weight, more preferably 15 to 20% by weight.

The content of the carboxylic acid monomer having an ethylenically unsaturated bond in the shell-forming monomer is preferably 1 to 10% by weight, more preferably 1 to 5% by weight.

The content of the chain transfer agent in the shell-forming monomer is preferably 0.1 to 2% by weight, more preferably 0.1 to 1% by weight.

The content of the reactive emulsifier in the shell-forming monomer is preferably 1 to 10% by weight, more preferably 1 to 5% by weight.

The weight ratio of the soft monomer to the hard monomer constituting the shell-forming monomer is preferably 1: 3 to 1: 6, more preferably 1: 3 to 1: 5.

In the starch polymer particles, Shell  Content relationship

The weight ratio of the core-forming monomer to the shell-forming monomer used for forming the starch-based polymer particles of the present invention is preferably from 1: 1 to 1: 4, more preferably from 1: 1.5 to 1: 3, 1.5 to 1: 2.5.

Starch-based  Polymer particles In the emulsion  Explanation of the ingredients involved

The starch-based polymer particles as the main constituent of the starch-based polymer particle emulsion according to an example of the present invention include all of the above-mentioned contents. The content of the starch-based polymer particles in the emulsion according to the present invention is not particularly limited, but is preferably 20 to 60% by weight, more preferably 35 to 60% by weight, based on the total weight of the emulsion.

The starch-based polymer particle emulsion according to one embodiment of the present invention includes an emulsifier. The starch-based polymer particle emulsion according to the present invention comprises an emulsifier. The emulsifier may be added at the time of the polymerization reaction for producing the starch-based polymer particles of the core-shell structure or may be added when emulsifying the starch-based polymer particles of the core-shell structure into the dispersion medium. The emulsifier can improve the dispersibility of the starch-based polymer particles, minimize the occurrence of aggregates during the production of the starch-based polymer particles, and improve the stability of the emulsion. Such an emulsifier is not limited in its kind, and includes, for example, a reactive emulsifier such as a phosphate ester emulsifier or a sulfate ester emulsifier; Anionic emulsifiers such as alkyldiphenyloxide disulfonates; And nonionic emulsifiers containing ethylene oxide or propylene oxide units, which may be used alone or in combination. In the present invention, the anionic emulsifier is preferably added in the step of forming the core of the starch-based polymer particles. The anionic emulsifying agent is not limited in its kind and includes, for example, sodium decyl diphenyl ether disulfonate (CAS No. 36445-71-3), sodium n-hexadecyl diphenyl disulfate Alkyldiphenyl oxides such as sodium n-hexadecyl diphenyl disulfonate (CAS registration no. 65143-89-7), sodium dodecyl diphenyl ether disulfate (CAS registration number 119345-04-9) (Alkyldiphenyloxide Disulfonate), among which sodium dodecyl diphenyl ether disulfonate (SODIUM DODECYL DIPHENYL ETHER DISULFATE; CAS No. 119345-04-9) is preferable. The amount of the anionic emulsifier is preferably 1 to 20 parts by weight, more preferably 5 to 15 parts by weight per 100 parts by weight of the core-forming monomer, but is not limited thereto. In the present invention, the nonionic emulsifier is preferably added in the step of forming the cores of the starch-based polymer particles, and more preferably, the other components are dispersed evenly in the aqueous phase in the step of preparing the pre-emulsion of the shell- It plays a role. Examples of the nonionic emulsifier include polyoxyethylene polyoxypropylene alkyl ethers and polyoxyethylene stearyl amines [commercial products such as SN-2 (Hannong Chemical, Korea)], Propylene copolymers (commercially available products such as MONOPOL PE), and the like. Of these, polyoxyethylene polyoxypropylene alkyl ethers such as polyoxyethylene polyoxypropylene alkyl ether . The amount of the nonionic emulsifier is preferably 0.1 to 5 parts by weight, more preferably 0.2 to 2 parts by weight per 100 parts by weight of the shell-forming monomer, but is not limited thereto. In the present invention, most of the reactive emulsifier forms a shell by polymerizing with other monomers in the step of forming a shell, and only the unreacted portion is present in a form dispersed in the emulsion. The reactive emulsifier may be selected from the group consisting of a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a propenyl group, The type thereof is not limited as long as it has at least one unsaturated bond functional group selected from a vinylidene group and a vinylene group. Examples of the reactive emulsifier usable in the present invention include ammonium salts of nonyl propenyl ethoxy ether sulfate (Aquaron HS-10 (DKS, Japan), SE-10 (Adeka, Japan) Sulfonic acid esters of polyoxyethylene allylglycidylnonylphenyl ether [commercially available products such as SETM (Adeka, Japan)], sulfonic acid esters of polyoxyethylene nonylphenyl ether sulfate Ammonium salts (HITENOL HSTM (DKS, Japan), etc.), and the like, and it is preferable to use esters of polyoxyethylene alkylphenylallylsodium sulfate.

The starch-based polymer particle emulsion according to the present invention may further comprise a polymerization initiator added during the production of the starch-based polymer particles.

Another aspect of the invention relates to a process for preparing starch-based polymer particle emulsions which can be used for surface coating of metal substrates. A method for producing a starch-based polymer particle emulsion according to an embodiment of the present invention comprises adding an anionic emulsifier to a starch liquefied liquid containing a starch hydrolyzate and mixing, adding a core-forming monomer and a polymerization initiator thereto, To obtain an aqueous emulsion comprising; And a step of adding a shell-forming monomer and a polymerization initiator to an aqueous emulsion containing the core and polymerizing to form a shell on the core. Wherein the core-forming monomer comprises a hard monomer, a soft monomer and a carboxylic acid monomer having an ethylenically unsaturated bond, wherein the shell-forming monomer is selected from the group consisting of a hard monomer, a soft monomer, a carboxylic acid monomer having an ethylenically unsaturated bond, The emulsions include reactive and reactive emulsifiers. The hard monomer has a ethylenically unsaturated bond and the homopolymer thereof has a glass transition temperature of 30 ° C to 250 ° C. The soft monomer has an ethylenically unsaturated bond and the glass transition temperature of the homopolymer is 10 ° C to -80 < 0 > C. Also, the reactive emulsifier may be selected from the group consisting of a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a propenyl group, a vinylidene group And at least one functional group selected from a vinylene group. Also, the content of the soft monomer in the core-forming monomer is 80 to 92% by weight, and the content of the hard monomer in the shell-forming monomer is 70 to 82% by weight. The weight ratio of the core-forming monomer to the shell-forming monomer in the step of preparing the starch-based polymer particle emulsion of the present invention is preferably 1: 1 to 1: 4. In the step of preparing the starch-based polymer particle emulsion of the present invention, the weight ratio of the hard monomer constituting the core-forming monomer to the soft monomer is preferably 1: 6 to 1:15, The weight ratio of monomer to hard monomer is preferably from 1: 3 to 1: 6.

The method for producing the starch-based polymer particle emulsion according to the present invention uses a starch liquefied liquid containing starch lysate as a base material. A method for producing a starch-based polymer particle emulsion according to the present invention will be described in detail first, followed by a description of a method for producing a starch-based liquefied liquid. The step of preparing a starch lysate containing starch hydrolyzate consists of adding a starch hydrolyzing enzyme to the starch suspension and decomposing the starch under predetermined pH and temperature conditions. At this time, the decomposition of the starch can be carried out by a batch-cooking or a jet-cooking method, and it is preferable to obtain a starch liquefied liquid containing starch hydrolyzate by the intermittent method. The intermittent method may be performed by reacting starch and starch degrading enzyme at 50 to 150 ° C, preferably 80 to 120 ° C for 30 to 300 minutes, preferably 60 to 200 minutes. The starcholytic enzyme includes alpha-amylase, beta-amylase, gluco-amylase, iso-amylase and the like, preferably mesophilic alpha-amylase or heat resistant alpha-amylase. The above starcholytic enzyme is commercially available. For example, when starch hydrolysis is carried out by the intermittent method, the pH of the starch suspension is preferably adjusted to a range of 4 to 8, and the amount of the starch degrading enzyme is 0.001 to 10 parts by weight , Preferably 0.01 to 1 part by weight, although it is not particularly limited.

When the starch hydrolyzate containing the starch hydrolyzate is prepared, the starch hydrolyzate is then polymerized with the core-forming monomer to form a core. Specifically, an emulsifier, preferably an anionic emulsifier, is added to and mixed with the starch liquefied liquid, followed by addition of a core-forming monomer and a polymerization initiator, followed by a polymerization reaction. An aqueous emulsion containing a core made of a starch-based copolymer can be obtained by the production step of the core. The core-forming monomers used in the step of forming the cores refer to the foregoing in the starch-based polymer particles. The polymerization initiator may be a thermal decomposition initiator or an oxidation-reduction initiator capable of radical polymerization, and examples thereof include sodium persulfate, potassium persulfate, t-butyl hydroperoxide, 2,2-azobisbutyronitrile, , 2'-azobis-2-methylbutyronitrile, cumene hydroperoxide and the like can be used, and water-soluble initiators such as sodium persulfate, potassium persulfate, and t-butyl hydroperoxide can be preferably used. If necessary, a reducing agent such as ascorbic acid, sodium formaldehyde sulfoxylate, sodium bisulfite and the like may be added. The polymerization initiator may be added before the addition of the monomer or simultaneously with the monomer. The amount of the polymerization initiator may be in the range of 0.1 to 8 parts by weight, preferably 0.2 to 5 parts by weight, per 100 parts by weight of the core-forming monomer.

The polymerization reaction temperature, the polymerization reaction pressure and the polymerization reaction time are not particularly limited in the production step of the core, and are, for example, from 60 to 100 ° C, preferably from 70 to 90 ° C, from 0.01 to 10 bar, At a pressure of 5 bar for 20 to 120 minutes, preferably 30 to 90 minutes. The reaction product obtained by the polymerization reaction is aged for minimizing unreacted monomers and for progressing a sufficient polymerization reaction. The aging temperature is kept the same as the polymerization reaction temperature, and the aging time is not limited to a great extent. By aging the reaction product, a core made of a starch-based copolymer and an emulsion containing the same can be obtained.

After preparing an aqueous emulsion of a core consisting of a starch-based copolymer, a shell is formed on the core. The step of forming the shell on the core may include a step of adding a shell-forming monomer and a polymerization initiator to the emulsion containing the core and performing a polymerization reaction, and may further include a step of further aging. At this time, the shell-forming monomer is preferably added in the form of a pre-emulsion comprising a hard monomer, a soft monomer, a carboxylic acid monomer having an ethylenically unsaturated bond, a chain transfer agent, a reactive emulsifier, a nonionic emulsifier and water. The pre-emulsion of the shell-forming monomer can be formed by dissolving the emulsifier in water and then adding a shell-forming monomer thereto. Generally, emulsion polymerization using a pre-emulsion is known to have an advantage of minimizing the amount of emulsifier used. In the present invention, when the shell-forming monomer is added in the form of pre-emulsion, not only the amount of emulsifier used is minimized but also the occurrence of aggregates is minimized, Can be improved. The shell-forming monomers used in the step of forming the shell refer to the foregoing in the starch-based polymer particles. On the other hand, in the step of forming the shell, the polymerization initiator may be added before the addition of the monomer or simultaneously with the monomer, and the amount thereof may be in the range of 0.1 to 8 parts by weight, preferably 0.2 to 5 parts by weight per 100 parts by weight of the shell- .

The polymerization reaction temperature, the polymerization reaction pressure and the polymerization reaction time in the shell formation step are not particularly limited, and are, for example, from 60 to 100 ° C, preferably from 70 to 90 ° C, from 0.01 to 10 bar, At a pressure of 5 bar for 60 to 240 minutes, preferably 100 to 200 minutes. The reaction product obtained by the polymerization reaction is aged for minimizing unreacted monomers and for progressing a sufficient polymerization reaction. The aging temperature is kept the same as the polymerization reaction temperature, and the aging time is not limited to a great extent. By aging the reaction product, starch-based polymer particles of core-shell structure and aqueous emulsion containing the starch-based polymer particles can be obtained.

The emulsion containing the starch-based polymer particles of the core-shell structure obtained by the formation of the core and shell is then cooled to 45-65 캜 and preferably post-treated to remove unreacted monomers. The post-treatment step for removing unreacted monomers can be carried out by a chemical method, a wet-removing method, or a high-temperature steam method, and is preferably carried out by a chemical method using an oxidizing agent and a reducing agent. The post-treatment step using the oxidizing agent and the reducing agent consists of adding an oxidizing agent and a reducing agent to the emulsion containing the starch-based polymer particles of the core-shell structure to induce oxidation and reduction reaction and aging. At this time, t-butyl hydroperoxide, cumenehydroperoxide and the like can be used as the oxidizing agent. Examples of the reducing agent include sodium hydrosulfite, sodium metabisulfite ) Can be used. The amount of the oxidizing agent and the reducing agent used in the post-treatment step is not particularly limited, and may be, for example, 0.001 to 1 part by weight, preferably 0.002 to 0.8 part by weight per 100 parts by weight of the emulsion. In the post-treatment step, the oxidation reaction and the reduction reaction may be carried out at about 40 to 60 DEG C for 10 to 100 minutes, preferably 20 to 40 minutes. In addition, the emulsion subjected to the oxidation reaction and the reduction reaction is aged to induce a sufficient reaction between the oxidizing agent and the reducing agent and the unreacted monomer. The aging is carried out at about 40 to 60 ° C for 20 to 150 minutes, preferably 30 to 100 minutes .

Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are intended to clearly illustrate the technical features of the present invention and do not limit the scope of protection of the present invention.

1. Analysis method

(1) Measurement of solid content of emulsion

The solids content of the emulsion was determined using the KS M IOS 3251 test method.

(2) Measurement of viscosity of emulsion

The viscosity of the emulsion was measured at 25 ° C using the KS M ISO 2555 (2009) test method.

(3) Evaluation of adhesion of coating film formed on metal substrate by emulsion

An emulsion was applied on the surface of an aluminum sheet to a thickness of about 100 mu m and dried in an oven at 130 DEG C for about 3 minutes to form a coating film. Thereafter, the adhesive strength between the film and the metal substrate was measured by a "Cross cut" test according to DIN EN ISO 2409, and the results were shown as scores from 0 (worst) to 5 (best).

(4) Evaluation of adhesion between coats formed by emulsion

An emulsion was applied on the surface of an aluminum sheet to a thickness of about 100 mu m and dried in an oven at 130 DEG C for about 3 minutes to form a coating film. Thereafter, the aluminum sheet on which the coated film was formed was cut into a size of 5 cm x 5 cm to prepare 30 sheets. Then, 30 sheets of aluminum sheets were stacked in order and kept at a temperature of 50 캜 for 24 hours under a pressure of 250 to 300 kgf using a heat press. Thereafter, the numbers of the aluminum sheets attached to each other were compared and compared, and the adhesion between the coating films was expressed as a score from 0 (the largest number of the attached aluminum sheets) to 5 (the smallest number of the attached sheets).

2. Starch The degradation product  Starch containing Liquefied  Produce

Preparation Example 1 of Starch Liquid Solution.

90.6 g of oxidized starch was added to 178.0 g of deionized water and dispersed to prepare a starch suspension. The pH of the starch suspension was adjusted to about 6.0 using a hydrochloric acid aqueous solution having a concentration of 7% by weight. In addition, 1 g of the heat-resistant alpha-amylase (Liquozyme supra, Novozyme, Denmark) was diluted with 99 g of deionized water to prepare a starch hydrolyzate solution. Then, 1.2 g of starch hydrolyzate was added to the starch suspension, and the mixture was reacted at about 90 캜 for about 120 minutes. After the reaction was completed, 0.6 g of hypochlorous acid was added to the reaction product to inactivate the enzyme and cooled to about 80 캜 to obtain a starch liquefied liquid containing the starch lysate.

3. Starch-based  An aqueous system comprising polymer particles Emulsion  Produce

Emulsion Preparation Example 1

To the reactor containing the starch liquefied liquid (obtained in Preparative Liquid Starch Production Example 1), 147.7 g of deionized water, 6.4 g of a reactive emulsifier (component: ester of polyoxyethylene alkylphenyl allyl sodium sulfate) and 6.4 g of a nonionic emulsifier Oxyethylene polyoxypropylene alkyl ether; CAS registration number: 103818-93-5) was added and filled with nitrogen. Thereafter, the reactor in a nitrogen atmosphere was heated to about 80 占 폚, and a polymerization initiator solution (a solution of 0.5 g of potassium persulfate and 0.03 g of sodium persulfate dissolved in 9 g of deionized water) and a core monomer mixture were added dropwise for 30 minutes To proceed the copolymerization reaction. The core monomer mixture was prepared by adding 20.0 g of methyl methacrylate, 5.0 g of methacrylic acid and 20.0 g of n-butyl acrylate in this order. After completing the dropwise addition of the polymerization initiator solution and the core monomer mixture, the copolymerization reaction product was agitated at about 80 캜 for about 60 minutes and aged to obtain a core made of the starch-based copolymer and an emulsion containing the same.

Thereafter, the temperature of the reactor in which the emulsion containing the core was held was maintained at about 80 DEG C, and a polymerization initiator solution (a solution of 2.8 g of potassium persulfate and 0.23 g of sodium persulfate in 55 g of deionized water) and a shell monomer The mixture was added dropwise for about 270 minutes to allow the copolymerization reaction to proceed on the core surface and to form a shell. The shell monomer mixture was prepared by sequentially adding 97.7 g of methyl methacrylate, 137.2 g of n-butyl acrylate, 40.0 g of styrene and 1.0 g of n-dodecyl mercaptan in this order. After completion of the dropwise addition of the polymerization initiator solution and the shell monomer mixture, the copolymerization reaction product was agitated at about 80 캜 for about 60 minutes and aged to obtain an emulsion containing the core-shell structure starch-based copolymer particles.

Thereafter, the emulsion containing the starch-based copolymer particles of the core-shell structure was cooled to about 55 DEG C, and an oxidant solution (a solution in which 0.9 g of t-butyl hydroperoxide was dissolved in 16 g of deionized water) and a reducing agent solution 0.6 g of sodium hydrosulfite dissolved in 8.0 g of deionized water) was added dropwise for 30 minutes and reacted to remove unreacted monomers. After the addition of the oxidizer solution and the reducing agent solution was completed, the reaction product was aged at about 55 캜 for 30 minutes and then cooled to room temperature to obtain an emulsion for metal-based coating. The obtained metal-based coating emulsion had a solids content of about 50% by weight.

Emulsion Preparation Example 2

147.7 g of deionized water, 6.4 g of an anionic emulsifying agent (component: Alkylether phosphate, ammonium salt) and 10.0 g of a nonionic emulsifier (component: polyoxyethylene polyoxyalkylene glycol) were added to the reactor containing the starch liquefied liquid Propylene alkyl ether; CAS registration number: 103818-93-5) was added and charged with nitrogen. Thereafter, the reactor in a nitrogen atmosphere was heated to about 80 占 폚, and a polymerization initiator solution (a solution of 0.5 g of potassium persulfate and 0.03 g of sodium persulfate dissolved in 9 g of deionized water) and a core monomer mixture were added dropwise for 30 minutes To proceed the copolymerization reaction. The core monomer mixture was prepared by adding 20.0 g of methyl methacrylate, 5.0 g of methacrylic acid and 20.0 g of n-butyl acrylate in this order. After completing the dropwise addition of the polymerization initiator solution and the core monomer mixture, the copolymerization reaction product was agitated at about 80 캜 for about 60 minutes and aged to obtain a core made of the starch-based copolymer and an emulsion containing the same.

Thereafter, the temperature of the reactor in which the emulsion containing the core was held was maintained at about 80 DEG C, and a polymerization initiator solution (a solution of 2.8 g of potassium persulfate and 0.23 g of sodium persulfate in 55 g of deionized water) and a shell monomer The mixture was added dropwise for about 270 minutes to allow the copolymerization reaction to proceed on the core surface and to form a shell. The shell monomer mixture was prepared by sequentially adding 97.7 g of methyl methacrylate, 137.2 g of n-butyl acrylate, 40.0 g of styrene and 1.0 g of n-dodecyl mercaptan in this order. After completion of the dropwise addition of the polymerization initiator solution and the shell monomer mixture, the copolymerization reaction product was agitated at about 80 캜 for about 60 minutes and aged to obtain an emulsion containing the core-shell structure starch-based copolymer particles.

Thereafter, the emulsion containing the starch-based copolymer particles of the core-shell structure was cooled to about 55 DEG C, and an oxidant solution (a solution in which 0.9 g of t-butyl hydroperoxide was dissolved in 16 g of deionized water) and a reducing agent solution 0.6 g of sodium hydrosulfite dissolved in 8.0 g of deionized water) was added dropwise for 30 minutes and reacted to remove unreacted monomers. After the addition of the oxidizer solution and the reducing agent solution was completed, the reaction product was aged at about 55 캜 for 30 minutes and then cooled to room temperature to obtain an emulsion for metal-based coating. The obtained metal-based coating emulsion had a solids content of about 50% by weight.

Emulsion Preparation Example 3

To the reactor containing the starch liquefied liquid (obtained in Preparative Liquid Starch Preparation Example 1), 147.7 g of deionized water, 6.4 g of an anionic emulsifier (ingredient: sodium dodecyl diphenyl ether disulfonate; CAS registration number: 119345-04-9) 1.6 g of a warm emulsifier (component: polyoxyethylene polyoxypropylene alkyl ether; CAS registration number: 103818-93-5) was added and filled with nitrogen. Thereafter, the reactor in a nitrogen atmosphere was heated to about 80 占 폚, and a polymerization initiator solution (a solution of 0.5 g of potassium persulfate and 0.03 g of sodium persulfate dissolved in 9 g of deionized water) and a core monomer mixture were added dropwise for 30 minutes To proceed the copolymerization reaction. The core monomer mixture was prepared by adding 20.0 g of methyl methacrylate, 5.0 g of methacrylic acid and 20.0 g of n-butyl acrylate in this order. After completing the dropwise addition of the polymerization initiator solution and the core monomer mixture, the copolymerization reaction product was agitated at about 80 캜 for about 60 minutes and aged to obtain a core made of the starch-based copolymer and an emulsion containing the same.

Thereafter, the temperature of the reactor in which the emulsion containing the core was held was maintained at about 80 DEG C, and a polymerization initiator solution (a solution of 2.8 g of potassium persulfate and 0.23 g of sodium persulfate in 55 g of deionized water) and a shell monomer The mixture was added dropwise for about 270 minutes to allow the copolymerization reaction to proceed on the core surface and to form a shell. The shell monomer mixture was prepared by sequentially adding 97.7 g of methyl methacrylate, 137.2 g of n-butyl acrylate, 40.0 g of styrene and 1.0 g of n-dodecyl mercaptan in this order. After completion of the dropwise addition of the polymerization initiator solution and the shell monomer mixture, the copolymerization reaction product was agitated at about 80 캜 for about 60 minutes and aged to obtain an emulsion containing the core-shell structure starch-based copolymer particles.

Thereafter, the emulsion containing the starch-based copolymer particles of the core-shell structure was cooled to about 55 DEG C, and an oxidant solution (a solution in which 0.9 g of t-butyl hydroperoxide was dissolved in 16 g of deionized water) and a reducing agent solution 0.6 g of sodium hydrosulfite dissolved in 8.0 g of deionized water) was added dropwise for 30 minutes and reacted to remove unreacted monomers. After the addition of the oxidizer solution and the reducing agent solution was completed, the reaction product was aged at about 55 캜 for 30 minutes and then cooled to room temperature to obtain an emulsion for metal-based coating. The obtained metal-based coating emulsion had a solids content of about 50% by weight.

Emulsion Preparation Example 4

To the reactor containing the starch liquefied liquid (obtained in Preparation Example 1 of the starch liquid solution), 147.7 g of deionized water, 3.2 g of an anionic emulsifier (ingredient: sodium dodecyl diphenyl ether disulfonate; CAS registration number: 119345-04-9) , 3.2 g of an emulsifier (component: ester of polyoxyethylene alkylphenyl allyl sodium sulfate) and 1.6 g of a nonionic emulsifier (component: polyoxyethylene polyoxypropylene alkyl ether; CAS registration number: 103818-93-5) . Thereafter, the reactor in a nitrogen atmosphere was heated to about 80 占 폚, and a polymerization initiator solution (a solution of 0.5 g of potassium persulfate and 0.03 g of sodium persulfate dissolved in 9 g of deionized water) and a core monomer mixture were added dropwise for 30 minutes To proceed the copolymerization reaction. The core monomer mixture was prepared by adding 20.0 g of methyl methacrylate, 5.0 g of methacrylic acid and 20.0 g of n-butyl acrylate in this order. After completing the dropwise addition of the polymerization initiator solution and the core monomer mixture, the copolymerization reaction product was agitated at about 80 캜 for about 60 minutes and aged to obtain a core made of the starch-based copolymer and an emulsion containing the same.

Thereafter, the temperature of the reactor in which the emulsion containing the core was held was maintained at about 80 DEG C, and a polymerization initiator solution (a solution of 2.8 g of potassium persulfate and 0.23 g of sodium persulfate in 55 g of deionized water) and a shell monomer The mixture was added dropwise for about 270 minutes to allow the copolymerization reaction to proceed on the core surface and to form a shell. The shell monomer mixture was prepared by sequentially adding 97.7 g of methyl methacrylate, 137.2 g of n-butyl acrylate, 40.0 g of styrene and 1.0 g of n-dodecyl mercaptan in this order. After completion of the dropwise addition of the polymerization initiator solution and the shell monomer mixture, the copolymerization reaction product was agitated at about 80 캜 for about 60 minutes and aged to obtain an emulsion containing the core-shell structure starch-based copolymer particles.

Thereafter, the emulsion containing the starch-based copolymer particles of the core-shell structure was cooled to about 55 DEG C, and an oxidant solution (a solution in which 0.9 g of t-butyl hydroperoxide was dissolved in 16 g of deionized water) and a reducing agent solution 0.6 g of sodium hydrosulfite dissolved in 8.0 g of deionized water) was added dropwise for 30 minutes and reacted to remove unreacted monomers. After the addition of the oxidizer solution and the reducing agent solution was completed, the reaction product was aged at about 55 캜 for 30 minutes and then cooled to room temperature to obtain an emulsion for metal-based coating. The obtained metal-based coating emulsion had a solids content of about 50% by weight.

Emulsion Preparation Example 5

(1) Preparation of Core Made of Starch-Based Copolymer and Emulsion Containing It

50.0 g of deionized water and 12 g of an anionic emulsifier (ingredient: sodium dodecyl diphenyl ether disulfonate; CAS registration number: 119345-04-9) were added to a reactor containing a starch liquefied liquid (obtained in Preparation Example 1 of Starch Liquid Solution) Nitrogen was charged. Thereafter, the reactor in a nitrogen atmosphere was heated to about 80 占 폚, and a polymerization initiator solution (a solution of 1.0 g of sodium persulfate and 0.08 g of sodium persulfate in 20 g of deionized water) and a core monomer mixture were added dropwise over 60 minutes To proceed the copolymerization reaction. The core monomer mixture was prepared by adding 104.0 g of methyl methacrylate, 104.0 g of styrene, 5.0 g of methacrylic acid, 103.0 g of n-butyl acrylate and 1.3 g of n-dodecyl mercaptan in this order. After completing the dropwise addition of the polymerization initiator solution and the core monomer mixture, the copolymerization reaction product was stirred at about 80 캜 for about 30 minutes and aged to obtain a core composed of the starch-based copolymer and an emulsion containing the same.

(2) Preparation of pre-emulsion of shell monomer mixture

(Component: polyoxyethylene polyoxypropylene alkyl ether; CAS registry number: 103818-93-5) 2.0 g of a reactive emulsifier (component: ester of polyoxyethylene alkylphenyl allyl sodium sulfite) and 8.0 g of a nonionic emulsifier g, and then 12.5 g of methyl methacrylate, 33 g of n-butyl acrylate and 12.5 g of methacrylic acid were slowly added dropwise in this order to prepare a pre-emulsion of the shell monomer mixture.

(3) Preparation of core-shell structure starch-based copolymer particles and emulsion containing the same

The temperature of the reactor containing the emulsion containing the core was maintained at about 80 DEG C, and the pre-emulsion of the mixture of the polymerization initiator (a solution in which 3.5 g of sodium persulfate was dissolved in 66.5 g of deionized water) and the shell monomer mixture was stirred for about 150 minutes And the copolymerization reaction was allowed to proceed on the core surface to form a shell. After completing the dropwise addition of the pre-emulsion of the polymerization initiator solution and the shell monomer mixture, the copolymerization reaction product was stirred at about 80 캜 for about 60 minutes and aged to obtain an emulsion containing the core-shell structure starch-based copolymer particles Respectively.

Thereafter, the emulsion containing the starch-based copolymer particles of the core-shell structure was cooled to about 55 DEG C, and an oxidant solution (a solution in which 0.9 g of t-butyl hydroperoxide was dissolved in 16 g of deionized water) and a reducing agent solution 0.6 g of sodium hydrosulfite dissolved in 8.0 g of deionized water) was added dropwise for 30 minutes and reacted to remove unreacted monomers. After the addition of the oxidizer solution and the reducing agent solution was completed, the reaction product was aged at about 55 캜 for 30 minutes and then cooled to room temperature to obtain an emulsion for metal-based coating. The obtained metal-based coating emulsion had a solids content of about 50% by weight. In addition, the viscosity of the obtained metal-based coating emulsion was 133 cPs.

Emulsion Preparation Example 6

(1) Preparation of Core Made of Starch-Based Copolymer and Emulsion Containing It

50.0 g of deionized water and 12 g of an anionic emulsifier (ingredient: sodium dodecyl diphenyl ether disulfonate; CAS registration number: 119345-04-9) were added to a reactor containing a starch liquefied liquid (obtained in Preparation Example 1 of Starch Liquid Solution) Nitrogen was charged. Thereafter, the reactor in a nitrogen atmosphere was heated to about 80 占 폚, and a polymerization initiator solution (a solution of 1.0 g of sodium persulfate and 0.08 g of sodium persulfate in 20 g of deionized water) and a core monomer mixture were added dropwise over 60 minutes To proceed the copolymerization reaction. The core monomer mixture was prepared by adding 12.5 g of methyl methacrylate, 104.0 g of styrene, 5.0 g of methacrylic acid and 38.0 g of n-butyl acrylate in this order. After completing the dropwise addition of the polymerization initiator solution and the core monomer mixture, the copolymerization reaction product was stirred at about 80 캜 for about 30 minutes and aged to obtain a core composed of the starch-based copolymer and an emulsion containing the same.

(2) Preparation of pre-emulsion of shell monomer mixture

(Component: polyoxyethylene polyoxypropylene alkyl ether; CAS registry number: 103818-93-5) 2.0 g of a reactive emulsifier (component: ester of polyoxyethylene alkylphenyl allyl sodium sulfite) and 8.0 g of a nonionic emulsifier g, and then, 104 g of styrene, 144.0 g of methyl methacrylate, 62.5 g of n-butyl acrylate, 5.0 g of methacrylic acid and 1.3 g of n-dodecyl mercaptan were slowly added dropwise in this order to obtain a shell monomer mixture ≪ / RTI > was prepared.

(3) Preparation of core-shell structure starch-based copolymer particles and emulsion containing the same

The temperature of the reactor containing the emulsion containing the core was maintained at about 80 DEG C, and the pre-emulsion of the mixture of the polymerization initiator (solution of 3.5 g of sodium persulfate in 66.5 g of deionized water) and the shell monomer mixture was heated for about 150 minutes And the copolymerization reaction was allowed to proceed on the core surface to form a shell. After completing the dropwise addition of the pre-emulsion of the polymerization initiator solution and the shell monomer mixture, the copolymerization reaction product was stirred at about 80 캜 for about 60 minutes and aged to obtain an emulsion containing the core-shell structure starch-based copolymer particles Respectively.

Thereafter, the emulsion containing the starch-based copolymer particles of the core-shell structure was cooled to about 55 DEG C, and an oxidant solution (a solution in which 0.9 g of t-butyl hydroperoxide was dissolved in 16 g of deionized water) and a reducing agent solution 0.6 g of sodium hydrosulfite dissolved in 8.0 g of deionized water) was added dropwise for 30 minutes and reacted to remove unreacted monomers. After the addition of the oxidizer solution and the reducing agent solution was completed, the reaction product was aged at about 55 캜 for 30 minutes and then cooled to room temperature to obtain an emulsion for metal-based coating. The obtained metal-based coating emulsion had a solids content of about 50% by weight. In addition, the viscosity of the obtained metal-based coating emulsion was 213 cPs.

Emulsion Preparation Example 7

(1) Preparation of Core Made of Starch-Based Copolymer and Emulsion Containing It

50.0 g of deionized water and 12 g of an anionic emulsifier (ingredient: sodium dodecyl diphenyl ether disulfonate; CAS registration number: 119345-04-9) were added to a reactor containing a starch liquefied liquid (obtained in Preparation Example 1 of Starch Liquid Solution) Nitrogen was charged. Thereafter, the reactor in a nitrogen atmosphere was heated to about 80 占 폚, and a polymerization initiator solution (a solution of 1.0 g of sodium persulfate and 0.08 g of sodium persulfate in 20 g of deionized water) and a core monomer mixture were added dropwise over 60 minutes To proceed the copolymerization reaction. The core monomer mixture was prepared by adding 12.5 g of methyl methacrylate, 5.0 g of methacrylic acid, 33.0 g of n-butyl acrylate and 30.0 g of 2-ethylhexyl acrylate in this order. After completing the dropwise addition of the polymerization initiator solution and the core monomer mixture, the copolymerization reaction product was stirred at about 80 캜 for about 30 minutes and aged to obtain a core composed of the starch-based copolymer and an emulsion containing the same.

(2) Preparation of pre-emulsion of shell monomer mixture

(Component: polyoxyethylene polyoxypropylene alkyl ether; CAS registry number: 103818-93-5) 2.0 g of a reactive emulsifier (component: ester of polyoxyethylene alkylphenyl allyl sodium sulfite) and 8.0 g of a nonionic emulsifier g, and then, 104 g of styrene, 144.0 g of methyl methacrylate, 62.5 g of n-butyl acrylate, 5.0 g of methacrylic acid and 1.3 g of n-dodecyl mercaptan were slowly added dropwise in this order to obtain a shell monomer mixture ≪ / RTI > was prepared.

(3) Preparation of core-shell structure starch-based copolymer particles and emulsion containing the same

The temperature of the reactor containing the emulsion containing the core was maintained at about 80 DEG C, and the pre-emulsion of the mixture of the polymerization initiator (solution of 3.5 g of sodium persulfate in 66.5 g of deionized water) and the shell monomer mixture was heated for about 150 minutes And the copolymerization reaction was allowed to proceed on the core surface to form a shell. After completing the dropwise addition of the pre-emulsion of the polymerization initiator solution and the shell monomer mixture, the copolymerization reaction product was stirred at about 80 캜 for about 60 minutes and aged to obtain an emulsion containing the core-shell structure starch-based copolymer particles Respectively.

Thereafter, the emulsion containing the starch-based copolymer particles of the core-shell structure was cooled to about 55 DEG C, and an oxidant solution (a solution in which 0.9 g of t-butyl hydroperoxide was dissolved in 16 g of deionized water) and a reducing agent solution 0.6 g of sodium hydrosulfite dissolved in 8.0 g of deionized water) was added dropwise for 30 minutes and reacted to remove unreacted monomers. After the addition of the oxidizer solution and the reducing agent solution was completed, the reaction product was aged at about 55 캜 for 30 minutes and then cooled to room temperature to obtain an emulsion for metal-based coating. The obtained metal-based coating emulsion had a solids content of about 50% by weight. Furthermore, the viscosity of the obtained metal-based coating emulsion was 150 cPs.

Emulsion Preparation Example 8

(1) Preparation of Core Made of Starch-Based Copolymer and Emulsion Containing It

90.0 g of deionized water and 12 g of an anionic emulsifier (component: Sodium dodecyl diphenyl ether disulfonate; CAS registration number: 119345-04-9) were added to the reactor containing the starch liquefied liquid (obtained in Preparation Example 1 of starch solution) Nitrogen was charged. Thereafter, the reactor in a nitrogen atmosphere was heated to about 80 占 폚, and a polymerization initiator solution (a solution of 1.0 g of sodium persulfate and 0.08 g of sodium persulfate in 20 g of deionized water) and a core monomer mixture were added dropwise over 60 minutes To proceed the copolymerization reaction. The core monomer mixture was prepared by adding 12.5 g of methyl methacrylate, 5.5 g of methacrylic acid, 83.0 g of n-butyl acrylate and 33.0 g of 2-ethylhexyl acrylate in this order. After completing the dropwise addition of the polymerization initiator solution and the core monomer mixture, the copolymerization reaction product was stirred at about 80 캜 for about 30 minutes and aged to obtain a core composed of the starch-based copolymer and an emulsion containing the same.

(2) Preparation of pre-emulsion of shell monomer mixture

(Component: polyoxyethylene polyoxypropylene alkyl ether; CAS registry number: 103818-93-5) 2.0 g of a reactive emulsifier (component: ester of polyoxyethylene alkylphenyl allyl sodium sulfite) and 8.0 g of a nonionic emulsifier g, and then 100 g of styrene, 110.0 g of methyl methacrylate, 50.0 g of n-butyl acrylate, 7.0 g of methacrylic acid and 1.3 g of n-dodecyl mercaptan were slowly added dropwise in this order to obtain a shell monomer mixture ≪ / RTI > was prepared.

(3) Preparation of core-shell structure starch-based copolymer particles and emulsion containing the same

The temperature of the reactor containing the emulsion containing the core was maintained at about 80 DEG C, and the pre-emulsion of the mixture of the polymerization initiator (solution of 3.5 g of sodium persulfate in 66.5 g of deionized water) and the shell monomer mixture was heated for about 150 minutes And the copolymerization reaction was allowed to proceed on the core surface to form a shell. After completing the dropwise addition of the pre-emulsion of the polymerization initiator solution and the shell monomer mixture, the copolymerization reaction product was stirred at about 80 캜 for about 60 minutes and aged to obtain an emulsion containing the core-shell structure starch-based copolymer particles Respectively.

Thereafter, the emulsion containing the starch-based copolymer particles of the core-shell structure was cooled to about 55 DEG C, and an oxidant solution (a solution in which 0.9 g of t-butyl hydroperoxide was dissolved in 16 g of deionized water) and a reducing agent solution 0.6 g of sodium hydrosulfite dissolved in 8.0 g of deionized water) was added dropwise for 30 minutes and reacted to remove unreacted monomers. After the addition of the oxidizer solution and the reducing agent solution was completed, the reaction product was aged at about 55 캜 for 30 minutes and then cooled to room temperature to obtain an emulsion for metal-based coating. The obtained metal-based coating emulsion had a solids content of about 50% by weight. In addition, the viscosity of the obtained metal-based coating emulsion was 282 cPs.

4. For metal substrate coating Emulsion  Physical property measurement result

The evaluation results of the adhesive strength of the coating film formed on the metal substrate by the emulsion for metal-based coatings obtained in Emulsion Production Examples 1 to 8 and the evaluation results of the adhesion between the coating films are shown in Table 1 below.

Emulsion classification for metal base coating Adhesion of coating film formed on metal substrate Cohesion between coats formed on a metal substrate Emulsion Production Example 1 5 0 Emulsion Preparation Example 2 0 0 Emulsion Preparation Example 3 3 3 Emulsion Preparation Example 4 3 3 Emulsion Preparation Example 5 3 One Emulsion Preparation Example 6 3 4 Emulsion Preparation Example 7 4 3 Emulsion Preparation Example 8 5 5

As shown in Table 1, when the coating film was formed on the surface of the metal substrate using the emulsion for metal-based coating prepared in the emulsion Production Example 8, the adhesion of the coating film was high and the coating film did not stick to each other.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Therefore, the scope of protection of the present invention should not be limited to the specific embodiments disclosed as the best mode, but should be construed as including all embodiments belonging to the claims attached hereto.

Claims (11)

As an aqueous emulsion containing water as dispersion medium and starch-based polymer particles and dispersion medium,
Wherein the starch-based polymer particles have a core-shell structure comprising a core formed by polymerization of a starch decomposition product and a core-forming monomer, and a shell formed on the core by polymerization of a shell-
Wherein the core-forming monomer comprises a hard monomer, a soft monomer, and a carboxylic acid monomer having an ethylenically unsaturated bond,
Wherein the shell forming monomer comprises a hard monomer, a soft monomer, a carboxylic acid monomer having an ethylenically unsaturated bond, a chain transfer agent and a reactive emulsifier,
Wherein the hard monomer has an ethylenic unsaturated bond and the homopolymer has a glass transition temperature of 30 ° C to 250 ° C,
Wherein the soft monomer has an ethylenic unsaturated bond and the homopolymer has a glass transition temperature of from 10 캜 to -80 캜,
The reactive emulsifier may be selected from the group consisting of a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a propenyl group, a vinylidene group, Having at least one functional group selected from a vinylene group,
The content of the soft monomer in the core-forming monomer is 82 to 90 wt%, the content of the hard monomer is 6 to 15 wt%, the content of the carboxylic acid monomer having the ethylenically unsaturated bond is 2 to 10 wt%
In the shell-forming monomer, the content of the hard monomer is 72 to 80 wt%, the content of the soft monomer is 15 to 20 wt%, the content of the carboxylic acid monomer having the ethylenically unsaturated bond is 1 to 5 wt%
The weight ratio of the soft monomer to the soft monomer constituting the core-forming monomer is 1: 6 to 1:12 and the weight ratio of the soft monomer to the hard monomer constituting the shell-forming monomer is 1: 3 to 1:
Wherein the weight ratio of the core-forming monomer to the shell-forming monomer in the starch-based polymer particles is from 1: 1 to 1: 4.
The method of claim 1, wherein the hard monomer is selected from the group consisting of styrene, methyl methacrylate, ethyl methacrylate, butyl methacrylate, acrylonitrile, methacrylonitrile, isobornyl acrylate, isobornyl methacrylate, Wherein the starch polymer particle emulsion is at least one selected from the group consisting of methacrylate, hydroxypropyl methacrylate, vinyltoluene, vinyl acetate, and vinyl chloride.
The composition of claim 1 wherein said soft monomer is selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, ethylhexyl acrylate, ethylhexyl methacrylate, lauryl methacrylate, hydroxyethyl acrylate, , And hydroxybutyl acrylate. ≪ RTI ID = 0.0 > 21. < / RTI >
The starch polymer particle according to claim 1, wherein the carboxylic acid monomer having an ethylenically unsaturated bond is at least one selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid and fumaric acid. emulsion.
The process of claim 1 wherein said chain transfer agent is selected from the group consisting of n-dodecyl mercaptan, t-dodecyl mercaptan, 1,5-pentanediol, 1,6-hexanediol, Methyl 3-mercaptopropionate, ethyl 3-mercaptopropionate, methyl 3-mercaptopropionate, methyl 3-mercaptopropionate, ethyl 3-mercaptopropionate, ethyl 3-mercaptopropionate, But are not limited to, erythritol tetrakis (3-mercaptopropionate), 2-ethylhexyl mercaptoacetate, ethyl 2-mercaptoacetate, 2-hydroxymethyl- Wherein the starch polymer particle emulsion is at least one selected from the group consisting of tetrakis (2-mercaptoacetate).
delete delete Adding an anionic emulsifier to a starch liquefied liquid containing a starch hydrolyzate and mixing, adding a core-forming monomer and a polymerization initiator to the mixture, and polymerizing to obtain an aqueous emulsion containing the core; And forming a shell on the core by adding a shell-forming monomer and a polymerization initiator to an aqueous emulsion containing the core and performing a polymerization reaction,
Wherein the core-forming monomer comprises a hard monomer, a soft monomer, and a carboxylic acid monomer having an ethylenically unsaturated bond,
Wherein the shell forming monomer comprises a hard monomer, a soft monomer, a carboxylic acid monomer having an ethylenically unsaturated bond, a chain transfer agent and a reactive emulsifier,
Wherein the hard monomer has an ethylenic unsaturated bond and the homopolymer has a glass transition temperature of 30 ° C to 250 ° C,
Wherein the soft monomer has an ethylenic unsaturated bond and the homopolymer has a glass transition temperature of from 10 캜 to -80 캜,
The reactive emulsifier may be selected from the group consisting of a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a propenyl group, a vinylidene group, Having at least one functional group selected from a vinylene group,
The content of the soft monomer in the core-forming monomer is 82 to 90 wt%, the content of the hard monomer is 6 to 15 wt%, the content of the carboxylic acid monomer having the ethylenically unsaturated bond is 2 to 10 wt%
In the shell-forming monomer, the content of the hard monomer is 72 to 80 wt%, the content of the soft monomer is 15 to 20 wt%, the content of the carboxylic acid monomer having the ethylenically unsaturated bond is 1 to 5 wt%
The weight ratio of the soft monomer to the soft monomer constituting the core-forming monomer is 1: 6 to 1:12 and the weight ratio of the soft monomer to the hard monomer constituting the shell-forming monomer is 1: 3 to 1:
Wherein the weight ratio of the core-forming monomer to the shell-forming monomer is from 1: 1 to 1: 4.
The method according to claim 8, wherein the shell-forming monomer is added in the form of a pre-emulsion consisting of a hard monomer, a soft monomer, a carboxylic acid monomer having an ethylenically unsaturated bond, a chain transfer agent, a reactive emulsifier, a nonionic emulsifier, Based polymer particle emulsion.
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