KR100830558B1 - Starch-vinyl graft copolymer, aqueous polymer emulsion containing the same and a method for preparing the same - Google Patents

Abstract

A starch-vinyl copolymer, its preparation method, an adhesive comprising the starch-vinyl copolymer, and a starch-vinyl copolymer aqueous emulsion containing the starch-vinyl copolymer are provided to improve biodegradability, to reduce the deterioration of adhesive strength, gloss and whiteness and to enhance stiffness. A starch-vinyl copolymer is prepared by copolymerizing starch and a vinyl monomer in a ratio of 30:70 to 90:10 by weight, wherein the vinyl monomer comprises an aromatic vinyl monomer and an aliphatic vinyl monomer in a ratio of 10:90 to 90:10 by weight. Preferably the vinyl monomer comprises further 10 parts by weight or less of a saturated carbonic acid monomer based on 100 parts by weight of an aromatic vinyl monomer and an aliphatic vinyl monomer.

Description

STARCH-VINYL GRAFT COPOLYMER, AQUEOUS POLYMER EMULSION CONTAINING THE SAME AND A METHOD FOR PREPARING THE SAME}

1 is a check whether the change of the copolymer of the present invention according to an embodiment of the present invention, the left is a photograph of the copolymer prepared by the comparative example and the right is a photograph of the copolymer prepared by the present invention .

[Industrial use]

The present invention relates to a starch-vinyl copolymer, a starch-vinyl copolymer aqueous emulsion, and a method for preparing the same, which improves the degree of water retention and rigidity, while improving the adhesion, gloss and whiteness, which are problems of the conventional starch copolymer.

[Private Technology]

The coating color of paper is the application of a coating solution consisting mainly of white pigments and adhesives on a sheet of paper. The purpose of coating is to improve the aesthetic value of products such as whiteness and gloss of paper and to improve printability. .

Coated paper is roughly classified into coated paper coated with pigment on relatively thin paper and coated paper coated with pigment on thick paperboard. Coating papers other than the pigment coated papers include information recording papers such as pressure-sensitive recording papers and thermal recording papers. In general, coated paper is used for printed matters such as magazines, advertisements, posters, calendars, and coated cardboard is used for packaging as a box.

In such paper coating, a binder capable of binding a pigment is used. Binders can be broadly classified into three types: latex adhesives including natural adhesives such as starch or protein, acrylic adhesives, and styrene-butadiene latex (SB latex).

Of these adhesives, starch or starch-containing adhesives are inexpensive and have the advantage of improving the repairability of the coating solution and the rigidity of the paper. However, luxury equipment is required and the whiteness and glossiness of the coated paper are deteriorated. There is. On the other hand, the most widely used styrene-butadiene latex has the advantage of excellent gloss, adhesion, but because of the use of petrochemicals is expensive, there is a problem that the rigidity of the paper is reduced.

Recently, due to environmental problems and rising oil prices, the development of coating adhesives that can replace expensive petrochemicals, that is, cheap and eco-friendly coating adhesives (binder) is urgently required.

In accordance with such development requirements, efforts have been made to develop adhesives using starch, that is, to develop copolymers using starch.

Specifically, a technique using modified starch or dextrin having a degree of substitution of starch of 0.05 or more, or using amylopectin starch such as waxy corn starch has been proposed, but such a technique has a relatively complicated manufacturing process and increases manufacturing cost. There is a problem.

In addition, as described in US Pat. No. 4,532,295, a technique of using starch as a protective colloid, rather than polymerizing starch and monomers, has been proposed. There is this.

In addition, a technique of using 1,3-butadiene to increase the content of starch has been proposed, but since it uses 10% or more of 1,3-butadiene present in the gas phase at room temperature, a high pressure reaction is carried out when preparing the copolymer. There is a problem that must be done.

In addition, European Patent 1,082,370 proposed a technique for using starch at a level of 5 to 30%, but the whiteness of the paper when the starch copolymer is used as a paper coating adhesive (binder) is changed to brown color when the copolymer is manufactured. Has the problem of falling.

Therefore, in the present invention, when the starch is used in the coating solution, the improvement of adhesion, gloss and whiteness, which is a problem, and the development of a starch-based copolymer which can obtain the repairability of the coating solution, which is an advantage of the starch, and the excellent paper rigidity, can be obtained. This is required.

In order to solve the problems of the prior art as described above, an object of the present invention is to provide a starch-vinyl copolymer which is inexpensive by increasing the content of starch and has improved adhesion and gloss and whiteness.

The present invention also aims to provide an aqueous emulsion comprising the starch-vinyl copolymer.

The present invention also aims to provide a method for producing the starch-vinyl copolymer.

In order to solve the problems of the prior art as described above, the inventors of the present invention while studying a copolymer containing starch does not decrease the gloss and whiteness, the weight ratio of starch: vinyl monomer is 30:70 to 90:10, The vinyl monomer is a starch-vinyl copolymer containing an aromatic vinyl monomer and an aliphatic vinyl monomer in a weight ratio of 10:90 to 90:10. Since the weight ratio of 30:70 to 90:10 was confirmed that the properties of excellent water retention and rigidity, which is an advantage of the adhesive (binder) containing starch is maintained to complete the present invention.

The present invention is polymerized from starch and vinyl monomers in order to solve the problems of the prior art as described above, the weight ratio of starch: vinyl monomer of the copolymer is 30:70 to 90:10, the vinyl monomer is an aromatic vinyl monomer And it provides a starch-vinyl copolymer comprising an aliphatic vinyl monomer in a weight ratio of 10:90 to 90:10.

The present invention also provides a starch-vinyl copolymer aqueous emulsion comprising the starch-vinyl copolymer and having a solid content of 20% to 70% by weight.

In the present invention, a vinyl monomer is added to the aqueous solution of starch so that the weight ratio of starch: vinyl monomer is 30:70 to 90:10, and the surfactant is 0.1 to 100 parts by weight based on 100 parts by weight of the monomer mixture in which the starch and the vinyl monomer are mixed. It provides a starch-vinyl copolymer manufacturing method comprising the step of polymerization by adding 10 parts by weight, 0.1 to 8 parts by weight of the initiator.

The present invention also provides an adhesive comprising the starch-vinyl copolymer or starch-vinyl copolymer aqueous emulsion.

Hereinafter, the present invention will be described in more detail.

In the present invention, starch may be a conventional starch, and specifically, may be corn starch, tapioca starch, potato starch, sweet potato starch or wheat starch, but is not limited thereto. Preferably the starch may be at least one selected from the group consisting of etherified starch, esterified starch, oxidized starch, oxidized ester starch, oxidized ether starch, acid treated starch and enzymatic starch, more preferably esterified starch. Can be. The etherified starch may be hydroxy propyl starch, hydroxy ethyl starch, carboxy methyl starch, cyanoethyl starch or amphoteric starch, preferably low viscosity ether starch or amphoteric oxidized starch, the ester starch is acetic acid starch Or maleic acid starch, preferably low viscosity ester starch, and the oxide starch may be hydrogen peroxide oxide starch or hypochlorous acid starch oxide.

In the present invention, the vinyl monomer may include an aromatic vinyl monomer and an aliphatic vinyl monomer in a weight ratio of 10:90 to 90:10.

In the present invention, the aromatic vinyl monomer is not particularly limited since it may be a conventional aromatic vinyl monomer, but specifically, styrene, α-methyl styrene, vinyl toluene, p-methyl styrene, 2-vinyl pyridine and 4-vinyl pyrine It may be one or more selected from the group consisting of dean. The aromatic vinyl monomer may preferably be styrene or vinyl toluene.

In the present invention, the aliphatic vinyl monomer may be a common aliphatic vinyl monomer, and is not particularly limited, but specifically, alkyl acrylate, vinyl cyanide compound, amide vinyl compound, hydroxyl group-containing vinyl compound, vinyl silicon compound, It may be at least one selected from the group consisting of difunctional vinyl monomers.

In the present invention, the alkyl acrylate is one or more selected from the group consisting of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl acrylate, 2-ethyl hexyl acrylate, butyl acrylate and butyl methacrylate It may be selected, the vinyl cyanide compound may be acrylonitrile, methacrylonitrile or a mixture thereof, the amide-based vinyl compound is acrylamide, methacrylamide, N-methyrol acrylamide, diacetone acrylamide , Dialkyl methacrylamide consisting of itaconeamide, methylene diacrylamide, diethyl acrylamide, dimethyl methacryl amide and diethyl methacryl amide, and the hydroxy group-containing vinyl compound Silver 2-hydroxy ethyl acrylate, 2-ha It may be at least one selected from the group consisting of hydroxy ethyl methacrylate, 3-hydroxy propyl acrylate and 3-hydroxy propyl methacrylate, wherein the silicon compound is vinyl trichloro silane, vinyl trimethoxy silane or these It may be a mixture of, the difunctional vinyl monomer may be at least one selected from the group consisting of divinyl benzene, diallyl benzene and divinylsulfonic acid, preferably in the present invention, the aliphatic vinyl monomer is butyl acrylate, methyl Methacrylate, 2-ethyl hexyl acrylate, more preferably butyl acrylate or 2-ethyl hexyl acrylate.

In the present invention, the content of the aromatic vinyl monomer and the aliphatic vinyl monomer may be a weight ratio (aromatic vinyl monomer: aliphatic vinyl monomer) of 10:90 to 90:10, preferably a weight ratio of 20:80 to 70:30 ( Aromatic vinyl monomers: aliphatic vinyl monomers). When the content of the aromatic vinyl monomer exceeds 90 weight ratio, there is a problem in that the polymerization stability of the copolymer and the strength of the coating solution are lowered. When the content of the aliphatic vinyl monomer is less than 10 parts by weight, the glossiness of the coated paper is reduced. If it is 90 parts by weight or more, workability problems occur when the glossiness of the coated paper is applied and when the coating solution is applied, and when it is less than 10 parts by weight, the copolymer tends to be broken.

The vinyl monomer may further include an unsaturated carboxylic acid monomer in an amount of 10 parts by weight or less based on 100 parts by weight of the total of the aromatic vinyl monomer and the aliphatic vinyl monomer in order to improve the adhesive strength and mechanical stability of the copolymer.

The unsaturated carboxylic acid monomer may be one or more selected from the group consisting of unsaturated monocarboxylic acid, unsaturated dicarboxylic acid and unsaturated dicarboxylic acid, specifically, may be acrylic acid, methacrylic acid, maleic acid, fumaric acid or itaconic acid, preferably Preferably, the ethylenically unsaturated carboxylic acid may be acrylic acid, methacrylic acid or maleic acid, but is not limited thereto.

The unsaturated carboxylic acid may be included in an amount of 10 parts by weight or less, preferably 7 parts by weight or less, based on 100 parts by weight of the total amount of the aromatic vinyl monomer and the aliphatic vinyl monomer. When the unsaturated carboxylic acid exceeds 10 parts by weight based on 100 parts by weight of the total of the aromatic vinyl monomer and the aliphatic vinyl monomer, the viscosity of the copolymer rises and difficult handling occurs.

The starch-vinyl copolymer may be a starch-vinyl copolymer prepared by emulsion polymerization.

In addition, the present invention comprises the starch-vinyl copolymer, the starch solid content is 20% to 70% by weight, preferably 30% to 60% by weight, more preferably 30% to 55% by weight. -Vinyl copolymer provides an aqueous emulsion. If the solid content is less than 30% by weight, it is difficult to produce a high concentration coating liquid during paper coating. If the solid content is 70% by weight or more, workability is degraded, and problems such as stiffness and the like occur. .

The viscosity of the starch-vinyl copolymer aqueous emulsion may be 10 to 3,000 cps, preferably 50 to 2,000 cps.

The copolymer

A vinyl monomer is added to the aqueous solution of starch so that the weight ratio of starch: vinyl monomer is 30:70 to 90:10, and 0.1 to 10 parts by weight of surfactant and initiator are added to 100 parts by weight of the monomer mixture in which the starch and the vinyl monomer are mixed. It can be prepared according to the starch-vinyl copolymer manufacturing method comprising the step of adding and polymerizing 0.1 to 8 parts by weight, it can be prepared in the form of an aqueous emulsion through the polymerization reaction.

The starch-vinyl copolymer manufacturing method is preferably

a) reacting alpha-amylase with starch;

b) a vinyl monomer is added to the reaction solution of step a) so that the weight ratio of starch: vinyl monomer is 30:70 to 90:10, and based on 100 parts by weight of the monomer mixture in which the starch and the vinyl monomer are mixed, a surfactant Adding 0.1 to 10 parts by weight, 0.1 to 8 parts by weight of initiator;

c) a method of preparing a starch-vinyl copolymer comprising polymerizing the mixture of step b).

The starch aqueous solution is added to 0.0001 parts by weight to 0.5 parts by weight of starch degrading enzyme based on the starch content in a mixed solution of starch and water, and then 30 minutes to 60 ℃ to 100 ℃, preferably 70 ℃ to 95 ℃ It can be prepared by reacting for 360 minutes.

The starch degrading enzyme may be an enzyme having conventional starch degrading ability, preferably alpha-amylase, but is not limited to a specific kind. The alpha-amylase may be a conventional alpha-amylase, preferably mesophilic alpha-amylase exhibiting the highest activity in the range of 60 ° C. to 80 ° C. or high temperature alpha-amylaseyl showing the highest activity at 90 ° C. to 105 ° C. Can be.

In the present invention, the surfactant may be a conventional surfactant, specifically, may be a nonionic surfactant, anionic surfactant or cationic surfactant. In the case of the cationic surfactant, since the aggregation of the coating liquid may occur, the surfactant may preferably be a nonionic surfactant or an anionic surfactant. The anionic surfactant may be sodium lauryl sulfate or dodecyl benzene sulfonate, and the nonionic surfactant is preferably in the group consisting of octylphenoxy polyoxyethylene ethers, polyoxyethylene nonyl phenyl ethers and twin series It may be any one or more selected, specifically octylphenoxy polyoxyethylene ethers may be OP-40, polyoxyethylene nonyl phenyl ethers may be NP-30, NP-40 or NP-50, twin series May be tween 20 or tween 80, but is not limited to a particular type.

The amount of the surfactant used to improve the stability of the aqueous emulsion of the copolymer may be 0.1 to 10 parts by weight, and preferably 0.5 to 6 parts by weight based on 100 parts by weight of the monomer mixture in which the starch and the vinyl monomer are mixed. . If the content of the surfactant is less than 0.1 parts by weight, the stability of the starch-vinyl copolymer is inferior, and if it is 10 parts by weight or more, there is a problem that the bubbles of the starch-vinyl copolymer increase.

In the present invention, the initiator may be a conventional initiator used in the polymerization reaction, specifically, may be an organic peroxide compound, an inorganic peroxide compound, a persulfate compound, cerium ammonium or a redox-based initiator. The persulfate compound may be potassium persulfate or ammonium persulfate, the redox-based initiator may be first ammonium sulfate, ascorbic acid or sodium bisulfite, and the cerium ammonium may be dicerium ammonium nitrate. Preferably the initiator is a persulfate compound or cerium ammonium.

The amount of the initiator may be 0.1 to 8 parts by weight, and more preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the monomer mixture in which the starch and the vinyl monomer are mixed. When the content of the initiator is less than 0.1 parts by weight, the emulsion polymerization takes place, and the reaction time increases. When the content of the initiator is more than 8 parts by weight, browning of the starch-vinyl copolymer may occur, the color may change, and the molecular weight decreases, thereby decreasing the strength of the paper. This can happen.

In the mixture for preparing the starch-vinyl copolymer, a vinyl monomer is added to a starch aqueous solution prepared by reacting starch degrading enzyme so that the weight ratio of starch: vinyl monomer is 30:70 to 90:10, and the starch and vinyl monomer are It can be prepared by adding 0.1 to 10 parts by weight of surfactant and 0.1 to 8 parts by weight of initiator with respect to 100 parts by weight of the mixed monomer mixture.

A chain transfer agent may be further added to the mixture for preparing the starch-vinyl copolymer to control the molecular weight of the copolymer.

In the present invention, the chain transfer agent may be a conventional chain transfer agent, and specifically, may be n-dodecyl mercaptan, t-dodecyl mercaptan or α-methylstyrene dimer, but is not limited thereto.

The amount of the chain transfer agent may be included in an amount of 5 parts by weight or less, preferably 3 parts by weight or less, based on 100 parts by weight of the monomer mixture in which starch and vinyl monomer are mixed. When the content of the chain transfer agent exceeds 5 parts by weight, the molecular weight may be too low, which may cause a problem that the strength of the paper coating layer is lowered.

An antifoaming agent or a thickener may be further added to the mixture for preparing the starch-vinyl copolymer, if necessary.

The polymerization may be carried out at 60 ° C. to 99 ° C., preferably at 75 ° C. to 95 ° C. for 30 minutes to 360 minutes, preferably 60 minutes to 300 minutes, and the polymerization reaction may be performed at 30 to 360 minutes. After running for minutes, the reaction can be terminated by cooling to 40 ° C. or less.

In addition, the method for preparing a starch-vinyl copolymer may further perform a step of drying after the polymerization reaction.

The present invention also provides an adhesive comprising the starch-vinyl copolymer or starch-vinyl copolymer aqueous emulsion.

The adhesive may be a conventional adhesive, preferably for paper coating binders, surface sizing agents, paint additives, adhesives of inks, dyes or pigments, for cardboard adhesives, more preferably for paper coating adhesives Or for cardboard adhesive.

Hereinafter, preferred examples are provided to aid in understanding the present invention, but the following examples are provided only for better understanding of the present invention, and the present invention is not limited by the following examples.

< Example >

Example  1: preparation of starch

In order to identify a starch suitable for producing a starch-vinyl copolymer, four kinds of starches including three types of oxidized starch or one type of etherified starch were used.

The oxidized ester starch (S3) was used as a starch (Zamyang Genex, South Korea) starch containing a viscosity of 9cps and 0.5% acetyl at 10% concentration, the etherified starch (S4) is a low viscosity ether As a starch, Sunsize C (Samyang Genex, South Korea) having a viscosity of 30 cps and a substitution degree of 0.015 at 10% concentration was used.

The starch oxide (S1 starch and S2 starch) was prepared by the following method.

Example  1-1. Of oxidized ester starch (S1 starch)  Manufacture 1

S1 starch is made into a slurry by adding 1,580 g of water and 1,000 g of sun size C3009 (Samyang Genex, South Korea), which is an oxide starch, to a stirrer, and adding 26 g of OSA (Octenyl succinic anhydride, TCI, Japan) to the slurry. After the pH of the mixed solution was raised to pH 8.5 by the addition of aqueous sodium hydroxide (NaOH) solution, the reaction was performed at 40 ° C for 1 hour. After carrying out the reaction, neutralize the pH of the starch slurry to 6.0 with hydrochloric acid, add 3,000 g of water to the neutralized reactant, and after purification, depressurize with 5 A filter paper (Adventec, Japan). It was dehydrated and dried using a 50 ° C blow dryer.

Example  1-2. Of oxidized ester starch (S2 starch)  Manufacture 2

S2 starch was carried out in the same manner as in Example 1-1 except for adding 26 g of acetic anhydride instead of OSA.

Example  2: Preparation of Starch-Vinyl Copolymer 1 (Starch: Monomer = 33: 67)

After mixing 166.2 g of S1 starch and 700 g of water in a 2-liter four-necked flask reactor equipped with a stirrer, the surfactants NP 40 (Honam Petrochemical, Korea) and Sodium Lauryl Sulfate (Miwon, Korea) were respectively g and 2 g were added. While stirring the mixture, 1 g of α-amylase (Termamyl 120 L, Novo, Denmark) was diluted in 99 g of water, and 10 g of 100 g of the diluted solution of α-amylase was added to the reactor. After the α-amylase was added, the reaction tank was heated to 85 ° C. and maintained for 1 hour to carry out the reaction.

After the reaction was carried out for 1 hour, 0.5 g of ammonium persulfate (large purified gold, Korea) dissolved in 2.5 g of water and 0.5 g of sodium bisulfite (revival industry, South Korea) dissolved in 2.5 g of water were added as an initiator. After adding 55.9 g of the mixed solution, the reaction was performed while maintaining for 30 minutes while stirring.

After the reaction for 30 minutes, 2.5 g of ammonium persulfate dissolved in 10 g of water as an initiator and 2.5 g of sodium bisulfite dissolved in 10 g of water were added dropwise to the reactor, and 278.8 g of the monomer mixture was added dropwise for 3 hours. The monomer mixture was a solution in which 162.7 g of styrene, 162.7 g of n-butyl acrylate, 6.9 g of acrylic acid, and 2.4 g of AMSD-GR ^™ (Goi Chemical, Japan), which were a chain transfer agent, were mixed. After completion of the dropwise addition of the initiator and the monomer mixture, the reaction was carried out for 30 minutes.After performing the reaction, 0.5 g of ammonium persulfate and 0.5 g of sodium bisulfite were dissolved in 10 g of water, and then maintained for 1 hour. The reaction was carried out.

After the reaction for 1 hour, 0.5 g of ammonium persulfate and 0.5 g of sodium bisulfite were further dissolved and added to 10 g of water, followed by additional reaction for 1 hour to remove residual monomer. After the reaction was completed, the mixture was cooled to 40 ° C. After cooling, the pH was adjusted to pH 8 with ammonia water.

The viscosity of the prepared copolymer was 66.5 cps, solid content was 40.0%. Viscosity was measured at 60 rpm with a spindle 2 using a Brookfield viscometer (LVF Brookfied viscometer, Massachusetts, USA), and the solids were dried in a 105 ° C. dryer for 3 hours.

Example  3: Preparation of Starch-Vinyl Copolymer 2 (Starch: Monomer = 36: 64)

After mixing 189.9 g of S2 starch and 430 g of water in a 2 L four-necked flask reactor equipped with a stirrer, 8 g and 2 g of surfactant NP 40 and sodium lauryl sulfate were added, respectively. While stirring the mixture, 1 g of α-amylase (Termamyl 120 L, Novo, Denmark) was diluted in 99 g of water, and 15 g of 100 g of dilution diluted with α-amylase was added to the reactor. After the α-amylase was added, the reaction temperature was raised to 85 ° C., and then maintained for 1 hour.

After the reaction was performed for 1 hour, 0.5 g of ammonium persulfate dissolved in 2.5 g of water and 0.3 g of sodium bisulfite dissolved in 2.5 g of water were added as an initiator, and 56.7 g of the monomer mixture solution was added thereto, followed by 30 minutes of stirring. Reaction was carried out.

After performing the reaction for 30 minutes, 283.6 g of the monomer mixture solution was added dropwise for 3 hours while dropping 2.5 g of ammonium persulfate dissolved in 12.5 g of water and 1.7 g of sodium bisulfite dissolved in 12.5 g of water as an initiator. The monomer mixture was a solution in which 185.7 g of styrene, 40.0 g of n-butyl acrylate, 100.0 g of 2-hexyl ethyl acrylate, 6.9 g of acrylic acid, and 0.8 g of AMSD-GR ^™ were mixed. After completion of the dropwise addition of the initiator and the monomer mixture, the reaction was carried out for 30 minutes.After performing the above reaction, 1.0 g of ammonium persulfate was dissolved in 20 g of water, and the mixture was added dropwise to the reaction tank for 30 minutes and maintained for 2 hours. Cool to 40 ° C.

After cooling, the pH was adjusted to pH 8 with sodium hydroxide solution. The viscosity of the prepared copolymer was 255 cps, solids was 51.9%. The viscosity was measured at 60 rpm with a spindle 2 using a Brookfield viscometer and the solids were dried for 3 hours in a 105 ° C. dryer.

Example  4: Preparation of Starch-Vinyl Copolymer 3 (Starch: Monomer = 40: 60)

After mixing 221.5 g of S3 starch and 743 g of water in a 2 L four-necked flask reactor equipped with a stirrer, 7 g and 1 g of surfactant NP 40 and sodium lauryl sulfate were added, respectively. While stirring the mixture, 1 g of α-amylase (Termamyl 120 L, Novo, Denmark) was diluted in 99 g of water, and 8 g of 100 g of the diluted solution of α-amylase was added to the reactor. After the α-amylase was added, the reaction temperature was raised to 85 ° C., and then maintained for 1 hour.

After performing the reaction for 1 hour, 0.3 g of ammonium persulfate dissolved in 2.0 g of water and 0.3 g of sodium bisulfite dissolved in 2.0 g of water were added as an initiator, and 33.3 g of the monomer mixture solution was added thereto, followed by 30 minutes of stirring. The reaction was carried out.

After performing the reaction for 30 minutes, 9.8 g of ammonium persulfate dissolved in 18.0 g of water and 2.7 g of sodium bisulfite dissolved in 18.0 g of water were added dropwise to the reactor with an initiator as a starting agent for 4 hours. The monomer liquid mixture was a solution which mixed 190.0 g of styrene, 80.0 g of 2-hexyl ethyl acrylate, 55.7 g of n-butyl acrylate, 6.6 g of acrylic acid, and 0.8 g of AMSD ^™ . After completion of the dropwise addition of the initiator and monomer mixture solution, the reaction was carried out for 30 minutes. After performing the reaction, 1.0 g of ammonium persulfate was dissolved in 10 g of water, and then maintained for 2 hours. The monomer was removed. After the reaction was completed, the mixture was cooled to 40 ° C. After cooling, the pH was adjusted to pH 8 with sodium hydroxide solution.

The viscosity of the prepared copolymer was 161 cps, solid content was 39.2% by weight. The viscosity was measured at 60 rpm with a spindle 2 using a Brookfield viscometer and the solids were dried for 3 hours in a 105 ° C. dryer.

Example  5: Preparation of Starch-Vinyl Copolymer 4 (Starch: Monomer = 43: 57)

In a 2-liter four-necked flask reactor equipped with a stirrer, 272.8 g of S3 starch was mixed with 749.2 g of water, and then 1 g of α-amylase (BAN 480L, Novo, Denmark) was diluted with 99 g of water to dilute α-amylase. 7.2 g of 100 g of one dilution was added to the reactor. After the α-amylase was added, the temperature of the reactor was increased to 75 ° C. and maintained for 30 minutes to carry out the reaction.

After the reaction was performed for 30 minutes, 7.2 g of the surfactant OP 40 (Ilchi Chemical, Korea) was dissolved in 40 g of water, and added to the reactor, and 3.96 g of ammonium persulfate dissolved in 80 g of water was added as an initiator. 363.6 g of the monomer mixture solution was added dropwise into the reactor for 2 hours 30 minutes. The monomer mixture was a solution in which 180.0 g of styrene, 180.0 g of n-butyl acrylate, and 3.6 g of dodecyl mercaptan were mixed. The reaction was carried out for 30 minutes after the dropping of the initiator and monomer was completed.

After performing the reaction, 0.396 g of t-butyl hydroxy peroxide (Lancaster, UK) was dissolved in 20 g of water as an organic initiator, added to the reactor, and further reaction was performed for 30 minutes to remove residual monomer. After the reaction was completed, the mixture was cooled to 40 ° C.

The viscosity of the prepared copolymer was 210 cps, solid content was 40.0%. The viscosity was measured at 60 rpm with a spindle 2 using a Brookfield viscometer and the solids were dried for 3 hours in a 105 ° C. dryer.

Example  6: Preparation of Starch-Vinyl Copolymer 5 (Starch: Monomer = 43: 57)

Example 6 was the same reaction as in Example 5, except that the reaction was carried out at a reaction temperature of 85 ℃. The viscosity of the prepared copolymer was 250 cps, solid content was 40.1%. The viscosity was measured at 60 rpm with a spindle 2 using a Brookfield viscometer and the solids were dried for 3 hours in a 105 ° C. dryer.

Example  7: Preparation of Starch-Vinyl Copolymer 6 (Starch: Monomer = 43: 57)

Example 7 uses Termamyl 120 L as α-amylase, The same reaction as in Example 5 was carried out except that the reaction was carried out at a reaction temperature of 90 ° C. The viscosity of the prepared copolymer was 1,290 cps, solid content was 40.3%. The viscosity was measured at 60 rpm with a spindle 2 using a Brookfield viscometer and the solids were dried for 3 hours in a 105 ° C. dryer.

Example  8: Preparation of Starch-Vinyl Copolymer 7 (Starch: Monomer = 53: 47)

In a 2-liter four-necked flask reactor equipped with a stirrer, 102.2 g of S3 starch and 238.6 g of S4 starch were mixed with 793.2 g of water, and then 1 g of α-amylase (BAN 480L, Novo, Denmark) was diluted with 99 g of water. 9.0 g of 100 g of the diluted solution of α-amylase was added to the reactor. After the α-amylase was added, the temperature of the reactor was raised to 80 ° C. and maintained for 30 minutes.

After the reaction was performed for 30 minutes, 5.4 g of the surfactant OP 40 was dissolved in 40 g of water and added to the reaction tank, 3.3 g of ammonium persulfate dissolved in 80 g of water was used as an initiator, and 303.0 g of the monomer mixture solution was added to the reaction tank. Was added dropwise for 2 hours 30 minutes. The monomer mixture is a solution in which 75.0 g of styrene, 225.0 g of butyl acrylate, and 3.0 g of dodecyl mercaptan are mixed. The reaction was carried out for 30 minutes after the dropping of the initiator and monomer was completed.

After performing the reaction, 0.33 g of t-butyl hydroxy peroxide as an organic initiator was dissolved in 20 g of water, added to a reactor, and further reaction was performed for 30 minutes to remove residual monomer. After the reaction was completed, the mixture was cooled to 40 ° C.

The viscosity of the prepared copolymer was 250 cps, solid content was 40.1%. The viscosity was measured at 60 rpm with a spindle 2 using a Brookfield viscometer and the solids were dried for 3 hours in a 105 ° C. dryer.

Example  9: Preparation of Starch-Vinyl Copolymer 8 (Starch: Monomer = 73: 27)

477.2 g of S3 starch was mixed with 552.8 g of water in a 2 L four-necked flask reactor equipped with a stirrer, and then 1 g of α-amylase (Termamyl 120 L, Novo, Denmark) was diluted with 99 g of water to prepare α-amylase. 7.2 g of 100 g of diluted diluent was added to the reactor. After the α-amylase was added, the temperature of the reactor was increased to 85 ° C. and maintained for 1 hour to carry out the reaction.

After the reaction was carried out for 1 hour, 7.2 g of the surfactant OP 40 was dissolved in 40 g of water, charged into a reactor, 3.6 g of potassium persulfate dissolved in 240 g of water was used as an initiator, and 180.9 g of the monomer mixture was added. It was dripped at the reactor for 4 hours. The monomer liquid mixture was a solution in which 90 g of styrene, 90 g of butyl acrylate, and 0.9 g of dodecyl mercaptan were mixed. The reaction was carried out for 30 minutes after the dropping of the initiator and monomer was completed.

After the reaction was carried out, 0.20 g of t-butyl hydroxy peroxide was dissolved in 20 g of water as an organic initiator, added to the reactor and further reaction was carried out for 30 minutes to remove residual equivalents. After the reaction was completed, the mixture was cooled to 40 ° C.

The viscosity of the prepared copolymer was 580 cps, solid content was 40.1%. The viscosity was measured at 60 rpm with a spindle 2 using a Brookfield viscometer and the solids were dried for 3 hours in a 105 ° C. dryer.

Example  10: Comparative example  1, manufacture

Comparative Example 1 was prepared by modifying the method described in Example 1 of European Patent 1,082,370.

Specifically, the type of starch used in Comparative Example 1 was used 102.7g of S3 starch of Example 1, the reaction was carried out at 82 ℃, the monomer mixture was 328.25g, the monomer mixture was styrene 162.5g, n 162.5 g of butyl acrylate and 3.25 g of n-butyl mecaptopropionic acid were mixed.

The starch content of the copolymer prepared in Comparative Example 1 was 23.1 wt%, the viscosity of the copolymer was 123 cps, solid content was 37.5 wt%. Viscosity was measured at 60 rpm with a No. 2 spindle using a Brookfield viscometer and the solids were dried in a 105 ° C. dryer for 3 hours.

Example  11: Comparative example  2, manufacturing

After mixing 272.8 g of a 2-liter four-necked flask S3 starch with a stirrer with 749.2 g of water, the temperature of the reactor was raised to 80 ° C. and maintained for 30 minutes. It melt | dissolved, it put in the reactor, 21 g of ammonium persulfate melt | dissolved in 100 g of water was added as an initiator, and 363.6 g of monomer liquid mixtures were dripped at the reactor for 2 hours 30 minutes. The monomer mixture is a solution in which 180.0 g of styrene, 180.0 g of n-butyl acrylate, and 3.6 g of dodecyl mercaptan are mixed. After the initiator and monomer dropping were completed, the reaction was carried out for 30 minutes.

After the reaction was carried out, 0.396 g of t-butyl hydroxy peroxide as an organic initiator was dissolved in 20 g of water, added to the reactor, and further reacted for 30 minutes to remove residual monomer. After the reaction was completed, the mixture was cooled to 40 ° C.

The copolymer prepared in Comparative Example 2 had a viscosity of 3,900 cps and a solid content of 40.1%. The viscosity was measured at 60 rpm with a spindle 2 using a Brookfield viscometer and the solids were dried for 3 hours in a 105 ° C. dryer.

Example  12: of copolymer Browning  Confirm

In order to determine whether browning and whiteness of the copolymer including starch were reduced, browning of the prepared copolymer was visually checked, and the results of comparing Example 4 with Comparative Example 1 are shown in FIG. 1. Indicated.

As shown in FIG. 1, the copolymers prepared in Examples 2 to 9 had a starch content of 30% by weight or more, and a milky white aqueous emulsion was prepared, but the starch copolymers prepared in Comparative Examples 1 and 2 It was confirmed that the color is dark brown, and when added as an adhesive (binder) to the paper coating solution was found to cause a problem that the whiteness of the paper is reduced.

Example  13: Coating amount  And Pottery  Check property

To apply the starch copolymer as a paper coating liquid adhesive (binder), the coating liquid was prepared as follows. The weight of the coating liquid components is based on solids.

Experimental example was prepared by putting 250 g of calcium carbonate (60K, Omi Korea), 17.5 g of starch copolymer prepared in Example 4, and 17.5 g of starch for coating into a 500 mL plastic beaker and using a stirrer (PL-S41DS, Poonglim, Korea). 10 minutes at 1000 rpm to prepare a coating solution.

The preparation of the control example was carried out by adding 17.5 g of SB latex (product name: H380, Hansol Chemical), a petroleum-based binder widely used as a paper coating adhesive instead of a starch copolymer, to prepare a coating solution. .

The experimental and control examples prepared above were measured for viscosity using a Brookfield viscometer, and the degree of repair was measured using an AA-GWR type water level gauge (DT Paper Science, Finland).

Paper coatings were used as a coating material of 75 g / m ² basis weight obtained from Hansol Paper. Coating was carried out using a rod bar, the coating amount was adjusted to 10 g / m ² on one side. After coating, drying was performed in a 105 ° C. dryer for 1 minute, followed by humidity treatment for 12 hours or longer to measure the rigidity and surface strength of the paper. The rigidity of the paper was measured using a bending stiffness tester (FRANK, Prugerate GmbH, Germany), and the surface strength was measured using IGT (Reprotest BV, Netherlands).

The measured viscosity, water retention, paper rigidity and paper surface strength are shown in Table 1 below.

Properties of Coating Liquid and Paper Strength Coating Liquid Viscosity (cps) Repair degree (g / m ² ) IGT Surface Strength (v / v / p) Stiffness (N) Experimental Example 1,100 28.9 176.6 0.69 Control 1,130 46.2 174.2 0.56

As shown in Table 1 above, when the experimental example prepared using the starch copolymer of Example 4 was used as a coating adhesive, the viscosity of the coating liquid was SB latex (product name: H380, Hansol Chemical). It was similar to the control prepared by the comparative example, the repair degree of the experimental example was about 35% improvement compared to the control. In addition, the surface strength of the coated paper was improved about 20% in the case of the rigidity, while maintaining a similar level of the experimental and control examples.

In the case of using the starch-vinyl copolymer of the present invention, not only the use of petrochemicals and biodegradable starch can be used to prepare an environment-friendly and significantly reduced production cost of the binder. In addition to improving the adhesion, gloss and whiteness, which are the problems of the copolymer, it is possible to improve the repairability of the coating solution while maintaining the surface strength similar to that of styrene-butadiene latex. It can be reduced, and the excellent effect which can improve the rigidity of the paper manufactured using this is recognized.

Claims (16)

Polymerized from starch and vinyl monomer, wherein the weight ratio of starch: vinyl monomer of the copolymer is 30:70 to 90:10, and the vinyl monomer is 10:90 to 90:10 by weight ratio of aromatic vinyl monomer and aliphatic vinyl monomer. A starch-vinyl copolymer comprising a. The starch-vinyl copolymer according to claim 1, wherein the vinyl monomer further comprises up to 10 parts by weight of an unsaturated carboxylic acid monomer based on 100 parts by weight of the total of the aromatic vinyl monomer and the aliphatic vinyl monomer. The starch-vinyl copolymer according to claim 1, wherein the copolymer is prepared by an emulsion polymerization method. The starch-vinyl copolymer according to claim 1, wherein the starch is at least one selected from the group consisting of etherified starch, esterified starch, oxidized starch, oxidized ether starch , oxidized ester starch, acid treated starch and enzyme treated starch. The starch-vinyl aerial of claim 1, wherein the aromatic vinyl monomer is at least one selected from the group consisting of styrene, α-methyl styrene, vinyl toluene, p-methyl styrene, 2-vinyl pyridine and 4-vinyl pyridine. coalescence. The starch of claim 1, wherein the aliphatic vinyl monomer is at least one selected from the group consisting of alkyl acrylates, vinyl cyanide compounds, amide vinyl compounds, hydroxyl group-containing vinyl compounds, vinyl silicon compounds, and difunctional vinyl monomers. Vinyl copolymers. The starch-vinyl copolymer according to claim 2, wherein the unsaturated carboxylic acid monomer is at least one selected from the group consisting of unsaturated monocarboxylic acid, unsaturated dicarboxylic acid and unsaturated dicarboxylic acid. The adhesive according to any one of claims 1 to 7, comprising the starch-vinyl copolymer. The adhesive according to claim 8, wherein the adhesive is for a paper coating binder or a cardboard adhesive. An aqueous starch-vinyl copolymer aqueous emulsion comprising the starch-vinyl copolymer according to claim 1 and having a solids content of 20 parts by weight to 70 parts by weight with respect to 100 parts by weight of the total emulsion. The method of claim 10, The copolymer aqueous emulsion has a viscosity of 10 to 3,000 cps starch-vinyl copolymer aqueous emulsion. A vinyl monomer is added to the aqueous solution of starch so that the weight ratio of starch: vinyl monomer is 30:70 to 90:10, and 0.1 to 10 parts by weight of surfactant and initiator are used based on 100 parts by weight of the monomer mixture in which the starch and the vinyl monomer are mixed. A starch-vinyl copolymer manufacturing method comprising the step of polymerization by adding 0.1 to 8 parts by weight. The method of claim 12, The starch aqueous solution is prepared by adding starch degrading enzyme 0.0001 parts by weight to 0.5 parts by weight based on the starch content in the mixed solution of starch and water, and then reacting at 60 ° C. to 100 ° C. for 30 to 360 minutes. Starch-vinyl copolymer production method. The method of claim 12, A method for producing a starch-vinyl copolymer, wherein the chain transfer agent is further added to 5 parts by weight or less based on 100 parts by weight of the monomer mixture in which the starch and the vinyl monomer are mixed. The method of claim 2, The content of the unsaturated carboxylic acid monomer is 2.03 to 10 parts by weight based on 100 parts by weight of the total of the aromatic vinyl monomer and aliphatic vinyl monomer. The method of claim 14, The content of the chain transfer agent is 0.137 to 5 parts by weight based on 100 parts by weight of the monomer mixture in which the starch and the vinyl monomer are mixed.

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