KR20020068862A - Cationic mixed polymer, producing method thereof, and additive for paper making containing it - Google Patents

Abstract

PURPOSE: A process of preparing a cationic polymer is provided by mixing starch and polymers such as guar gum, locust bean gum, alginate and the like, making dry cationization of the mixture, dry aging and then grounding thereof. Whereby, the product exhibits high retention and dehydration and increases the strength of prepared paper. CONSTITUTION: Starch and polymers selected from guar gum, locust bean gum, karaya gum, alginate and carboxymethylcellulose are mixed in a ratio of 0.1:99.9 to 50:50, and the mixture is subject to dry cationization, dry agitation and then grind to produce a mixed polymer. The starch is selected from potato starch, maize starch, tapioca starch, glutinous corn starch and sweet potato starch. An additive for paper making contains 1 to 10% by weight of a cationic mixed polymer in the shape of a gelatinized aqueous solution.

Description

Cationic mixed polymer, preparation method thereof and paper additives including same {CATIONIC MIXED POLYMER, PRODUCING METHOD THEREOF, AND ADDITIVE FOR PAPER MAKING CONTAINING IT}

The present invention relates to mixed polymers, and more particularly, to cationic mixed polymers that can be used as paper additives.

The domestic paper industry has exceeded the annual average growth rate of 10% for 10 years, but the pulp's self-sufficiency is only about 20%, and the rest is dependent on import and recycling of highland.

Recently, the use of recycled pulp is gradually increasing in terms of environmental protection and resource conservation, and additives for effective use of recycled pulp and related researches are being actively conducted.

Among the various additives, cationic starch is not only the most widely used dry tenacity enhancer but also reacts with various fillers, fines and fibers in the paper to improve retention and dehydration and to reduce wastewater load. . However, due to the closure of the papermaking process and the deterioration of water quality, the effect of cationic starch is greatly reduced.

As the effect of cationic starch as an additive decreases, the amount of polymer used as an additive has increased recently. One example is the use of guar gum. Guar gum is used in its natural state and recently used as cationized as starch.Curated guar gum by introducing quaternary ammonium groups changes the zeta potential of fine powder and filler so that it is easily combined with long fibers and retains fine powder. It has the effect of improving the efficiency and dehydration.

However, both cationic starch and guar gum as additives for papermaking have a disadvantage in that the cationic starch has a problem in performance when the conditions of use water deteriorate and the electrical conductivity increases. In addition, guar gum can not be used in high-quality paper due to the color, and unlike starch, there is a disadvantage in that it requires a lot of energy to reduce the strength and dissolve the paper.

The present invention for solving the above problems is dry cationic, dried and granulated by mixing the starch and the polymer in a specific ratio, the conditions that are easy to apply to the process when used in the papermaking process and the process water shows high conductivity For the paper-making process including the cationic mixed polymer, its manufacturing method and the prepared cationic mixed polymer which can also function at high retention rate and dehydration rate and impart high tensile strength and surface strength to the final product paper. It is an object to provide an additive.

The present invention for achieving the above object comprises the steps of mixing a starch and a polymer; Subjecting the mixture to a dry cationization reaction; Dry aging the mixture; And a method for producing a cationic mixed polymer comprising the step of pulverizing the dry matured mixture, a cationic mixed polymer prepared by the method, and a papermaking additive comprising the cationic mixed polymer.

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

The process for producing a cationic mixed polymer used as a papermaking additive according to the present invention is as follows.

Starch in the present invention can be used to select a suitable starch in relation to the price and performance of the final product, in general, corn starch, tapioca starch, potato starch, sweet potato starch and waxy corn starch.

As the polymer to be mixed with starch, guar gum, locust bean gum, alginate, karaya gum, carboxy methyl cellulose (CMC) and the like are preferably used, and guar gum is particularly preferable.

In order to prepare a cationic mixed polymer, starch and polymer are first dry mixed to prepare a mixed polymer.

The mixing ratio of starch and polymer, which is one of the important factors for determining the quality of the final product, is preferably 0.1: 99.9-50:50 by weight, and particularly preferably 1:99-10:90. When the mixing ratio of the polymer is lower than the ratio, the mixing effect of the polymer hardly occurs in the final product. When the mixing ratio is exceeded, the mixing process is impossible due to the increase in the midpoint of the cation reaction and the cost increases.

Mixing of the starch and the polymer may be carried out by conventional methods, generally mixing in a powder mixer.

The mixture of starch and polymer is placed in a powder stirrer, followed by the addition of sodium hydroxide, a small amount of water, a crosslinking agent, and a cationic reaction reagent, followed by a dry cationic reaction by the addition of an anti-caking agent.

Sodium hydroxide added to the mixture of starch and polymer serves as a catalyst to help the reaction reagent in the form of epoxy react with the mixture, the amount of sodium hydroxide is preferably 1-10% by weight based on the total weight of the mixed polymer. If the amount of the additive is less than that can not function as a catalyst, if the addition amount is higher than the reaction solid content is low and there is a problem that does not dissolve all sodium hydroxide within the water content range used for the reaction.

In some cases, an anti-caking agent is added for a smooth dry reaction. That is, when the content of the polymer in the mixture exceeds 5% it is preferable to add an anti-binder for smooth stirring. Anti-binders that can be used include microcrystalline cellulose, sodium calcium aluminosilicate, and the like, and they are preferably added in an amount of 1-3% by weight based on the weight of the mixed polymer.

A minimum amount of water is required to cationic the mixed polymer of starch and polymer, and the small amount of water added serves to raise the pH in the dry reaction system by dissolving the added alkali. At this time, the amount of water is preferably 3 to 10% by weight of the mixed polymer. If the amount of water added is less than 3%, the added sodium hydroxide is not sufficiently dissolved, so that the pH of the system for cationization cannot be obtained, and if more than 10% of water is added, the mixed polymer clumps to cationize. This is because there is a problem that does not occur evenly, as well as a problem that takes a long time to dry after the reaction.

A crosslinking agent may be added to prevent a decrease in viscosity during the reaction of the cationized mixed polymer, and it is preferable to use phosphoric acid phosphate, sodium trimetaphosphate, epichlorohydrin, adipic acid, or the like as the crosslinking agent. It is particularly preferable to use adipic acid. At this time, the amount of the crosslinking agent can be adjusted depending on the desired viscosity of the final product, but usually 2-5% by weight is appropriate.

In the case of the conventional cationic starch, there is a problem in the retention rate increase due to the disadvantage that the viscosity decreases rapidly when the substitution degree is increased to 0.1 or more, but in the case of the present invention, the viscosity decreases due to the synergistic effect of the polymer and the crosslinking agent. This does not happen.

It is preferable to use a reagent capable of carrying a cationic group, that is, a reaction reagent containing a quaternary ammonium group, and it is particularly preferable to use an epoxy form of 2,3-epoxypropyl trimethylammonium chloride. . As such, by using the activated form in the epoxy form, it is possible to proceed with the dry reaction with the minimum content of water.

The cationization reagent may change the amount of addition depending on the degree of substitution of the desired product, but in order to obtain a product having a range of 0.03-1.0, which can be used according to the manufacture paper and the type of water used, based on 100% of the active monomer content The amount of cationization reagent added can be controlled up to 5-30% of the mixed polymer. If less than 5% is added, there is a problem in increasing the degree of substitution due to cationization, and if it is added more than 30%, reagents that do not react may remain, causing problems in the drying process.

After the addition of the additives the reactants are mixed. In this case, the mixing is generally performed by a mixer, and when mixing with a general mixer, the reaction efficiency may be lowered, and therefore, mixing with a vacuum mixer is preferable to increase the reaction efficiency. When mixing with a general mixer, the mixing time is preferably 5-60 minutes, and when using a vacuum mixer is preferably 1-30 minutes.

The mixed polymer, which has been completely mixed, is dried and granulated in a reaction tank through which air can pass. At this time, the aging period is determined until all the added reaction reagents are reacted. This maturation period can be adjusted according to the moisture content and storage temperature of the product, usually 3-7 days is preferred. In other words, if the storage temperature is 20 ℃ or less, aged for 7 days, if the storage temperature is 20 ℃ is preferably aged for about 3 days.

The matured polymer shows 5-20% water content, 5% water content. If it is less than one, there is a possibility of causing dust problems when using the product, and if more than 20%, the fluidity of the powder is inferior. The maturation period can be extended to control the moisture content.

The mixed polymer after aging is present in the form of granules of starch and polymer, whereby a cationic mixed polymer is obtained by pulverizing it. At this time, grinding to 50-200 mesh is preferable to use as an additive for papermaking.

The cationic mixed polymer prepared as described above may be used alone or in combination with a conventional internal additive for papermaking additives.

The above-mentioned cationic mixed polymer is used to prepare a papermaking additive. In order to use it in the papermaking process, it is generally preferable to prepare in the form of an aqueous solution which is gelatinized at a concentration of 1-10%.

The produced papermaking additives can be used in the same way as conventional papermaking additives, it is common to use before and after the head box or screen. When the additive for papermaking is added to the papermaking process, the amount of the cationic mixed polymer to be added is preferably 0.5-3% by weight relative to the dry pulp. In this range, the retention rate and the degree of freedom of the process are improved and Most effective for improving the quality of finished paper.

The above additives for papermaking showed up to two times retention and dehydration rate during the papermaking process compared to the case of adding cationic starch or guar gum with the same degree of substitution, and high tensile and surface strength in the finished paper. Indicated.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are only for illustrating the present invention in more detail, it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples in accordance with the gist of the present invention. .

(Example 1)

Preparation of Cationic Mixed Polymer Using Various Starches

Corn, potato, tapioca, waxy corn starch and guar gum were mixed in various ratios, water, sodium hydroxide and adipic acid as crosslinking agent were added, and then 2,3-epoxypropyl trimethylammonium having an active monomer content of 70% as a cationic reagent. Chloride was added 10-15% of the total weight of the mixture.

After the mixture was stirred for 15 minutes in a vacuum mixer and put into a bag through air and aged for 7 days, the substitution degree and water content of the cationic mixed polymer were measured and shown in Table 1 below.

Starch Type Starch (g) Guar gum (g) NaOH (g) Water (ml) Adipic acid (g) Cationization reagent (g) product Moisture content (%) Degree of substitution (DS) ¹⁾ Viscosity ²⁾ (cps) Corn starch 490 10 15 30 20 50 12.5 0.178 28 475 25 20 30 20 50 12 0.169 38 450 50 25 30 20 50 11.5 0.170 47 450 50 25 30 20 75 12 0.203 52 Potato starch 490 10 15 30 20 50 17.5 0.177 39 475 25 20 30 20 50 16.8 0.174 45 450 50 25 30 20 50 16.7 0.170 56 450 50 25 30 20 75 17 0.215 60 Tapioca Starch 490 10 15 30 20 50 15 0.174 37 475 25 20 30 20 50 14.6 0.177 42 450 50 25 30 20 50 14.1 0.176 55 450 50 25 30 20 75 14.5 0.210 58 Waxy Corn Starch 490 10 15 30 20 50 13 0.176 39 475 25 20 30 20 50 12.7 0.172 46 450 50 25 30 20 50 12.4 0.177 57 450 50 25 30 20 75 12.5 0.220 59

1) DS: Degree of substitution (DS) of the cationic mixed polymer was calculated using Equation 1 below using an increased nitrogen content compared to natural starch and guar gum.

2) Viscosity: measured using a Brookfield viscometer at a concentration of 0.5% at 25 ° C.

In the results of Table 1, there was no large change in the degree of substitution according to the type of starch, it can be seen that only the difference in moisture content and viscosity that comes from the difference of raw materials. Therefore, it can be seen that there is no problem depending on the type of starch in preparing the cationic mixed polymer using the starch.

In addition, even when the guar gum content was changed, there was almost no change in the degree of substitution and water content, and the viscosity increased according to the guar gum content. It can be seen that.

In addition, it can be seen that cationic mixed polymers having various degrees of substitution can be prepared by controlling the amounts of sodium hydroxide and cationization reagents used as catalysts.

(Example 2)

Preparation of Cationic Mixed Polymers for Corrugated Paper, Liner Paper and Newspaper

40 g of guar gum was mixed with 460 g of corn starch, 20 g of powdered sodium hydroxide and 30 ml of water were added, 15 g of sodium hydroxide and 20 g of adipic acid were added, followed by 70% of 2,3-epoxypropyl trimethylammonium chloride of the active monomer. 75 ml was added.

The mixture was stirred in a vacuum mixer for 30 minutes, then transferred to an air storage tank, aged at 25 ° C. for 5 days, and then crushed into 100 mesh to form a cationic mixed polymer that can be used for corrugated paper, liner paper, and newspaper paper.

(Example 3)

Preparation of Cationic Mixed Polymer for Woodfree Paper

After mixing 20 g of guar gum with 480 g of potato starch, add 15 g of powdered sodium hydroxide and 30 ml of water, add 15 g of sodium hydroxide and adipic acid, and add 50 ml of 2,3-epoxypropyl trimethylammonium chloride of 70% of the active monomer. It was.

The mixture was stirred for 20 minutes with a vacuum mixer, and then transferred to an air storage tank, aged at 20 ° C. for 7 days, and then pulverized into 100 mesh to complete a cationic mixed polymer usable for white paper and printing paper.

(Example 4)

Papermaking Process Addition Effect of Cationic Mixed Polymer

50 g of guar gum were mixed with 450 g of corn starch and potato starch, 25 g of powdered sodium hydroxide and 30 ml of water were added, 20 g of sodium hydroxide and adipic acid were added, followed by 70% of 2,3-epoxypropyl trimethyl of the active monomer. 80 ml of ammonium chloride was added. The mixture was stirred in a vacuum mixer for 20 minutes, transferred to an air reservoir, aged at 25 ° C. for 4 days, and then ground to 100 mesh to complete a cationic mixed polymer.

The paper stock was collected from S-concentrator producing newspaper paper with a concentration of 3-4% of slurry. The stock was diluted to 0.5% and 0.3% concentrations, respectively, for the measurement of microdispersity and freeness, and adjusted to have an electrical conductivity of 4000 mW / cm by adding sodium chloride at a concentration of 4M.

0.5% cationic mixed polymer was gelatinized at 95 ° C. for 30 minutes to evaluate the applicability of the starch of the cationic mixed polymer.

After stirring 500 ml of 0.5% of the drying material for 30 seconds at 800rpm, 1.0% of the cationic polymer was added to the drying material, and again stirred at 800rpm for 30 seconds to induce aggregation of the composition of the stock, followed by retention. After taking the sample for measurement, 1000 ml of 0.3% dry matter was stirred at 800 rpm for 30 seconds, and then the cationic polymer was added 1.0% to the total dry matter and stirred at 800 rpm again for 30 seconds to determine the composition of the stock. After inducing aggregation, a sample for measuring the degree of freedom was taken.

The microdispersity and the degree of freedom of the sample were measured to compare retention rates and degree of freedom with conventional cationic starch, and the results are shown in Table 2 below. Retention rate and freeness were measured according to TAPPI test method T 261 cm-90 and T 227 om-94.

sample No sample added Cationic Corn Starch Cationic Potato Starch Cationic Mixed Polymer (Corn Starch) Cationic Mixed Polymer (Potato Starch) Retention Rate (%) 47 55 62 70 76 Yeosu-do (ml) 175 200 240 275 290

As can be seen in Table 2, the cationic mixed polymer prepared with corn starch and potato starch as the main raw material was found to be superior in retention rate and Yeosu, compared with the conventional cationic starch alone, and the mixed polymer using corn starch. In the case of also showed a superior function than the cationic potato starch.

(Example 5)

Improvement of Paper Properties of Cationic Mixed Polymers

After mixing 25 g of guar gum with 475 g of potato starch, add 20 g of powdered sodium hydroxide and 25 ml of water, add 15 g of sodium hydroxide and adipic acid, and add 70 ml of 2,3-epoxypropyl trimethylammonium chloride of 70% of the active monomer. It was.

The mixture was stirred in a vacuum mixer for 30 minutes, transferred to an air reservoir, aged at 25 ° C. for 5 days, and then ground to 100 mesh to complete a cationic mixed polymer.

In order to prepare paper, 0.5% cationic mixed polymer solution was gelatinized at 95 ° C. for 30 minutes while stirring the prepared stock at 800 rpm, and 0.5-2.0% was added to the total stock, followed by further stirring for 30 seconds. After stirring, the stock was transferred to a circular weeding machine. Basis weight of the sheet was adjusted to 60 ± 1 g / ㎡. The wetland produced in the circular weeding machine was compressed and dehydrated at 3.5 kg / ㎠ for 5 minutes and then blow-dried for 30 minutes.

Tensile strength and internal bonding strength of the paper produced above were measured and the results are shown in Table 3 below.

Sample addition rate (%) 0 0.5 1.0 1.5 2.0 Internal bonding strength (KJ / ㎡) 240 300 360 420 480 Tensile Strength (Nm / g) 37 39 41 43 44

In the results of Table 3, it can be seen that the cationic mixed polymer is excellent in the properties of the paper as well as the finished product.

Unlike the conventional additives, the cationic mixed polymer of the present invention can be used even when the water used in the paper manufacturing plant exhibits high electrical conductivity as the content of the pollutant increases, and shows a high retention rate and dehydration rate. Increase the strength of the finished paper. Therefore, it is possible to use a product of the desired quality according to the type and manufacturing process of the paper and can obtain excellent process conditions and products compared to the conventional additives.

In addition, since it can be easily applied in the same manner as the conventional cationic starch in the general papermaking process, it can solve the problem of dissolution when using the conventional guar gum, the viscosity decrease due to the synergistic effect of the polymer and crosslinking agent Since this does not occur, there is no problem in raising the retention rate due to a sharp decrease in viscosity, which is a problem when using conventional cationic starch.

Claims (9)

Mixing starch and polymer; Subjecting the mixture to a dry cationization reaction; Dry aging the mixture; And Method for producing a cationic mixed polymer comprising the step of grinding the dry mature mixture. The method of claim 1, The starch is a method of producing a cationic mixed polymer, characterized in that selected from potato starch, corn starch, tapioca starch, waxy corn starch and sweet potato starch. The method of claim 1, Wherein said polymer is selected from guar gum, locust bean gum, karaya gum, alginate and carboxymethyl cellulose (CMC). The method of claim 1, The mixing ratio of the starch and the polymer is 0.1: 99.9-50:50 The method of producing a cationic mixed polymer, characterized in that. The method of claim 1, The cationization process is a method of producing a cationic mixed polymer, characterized in that by adding and mixing a cationization reagent, sodium hydroxide, a crosslinking agent and a small amount of water to the mixture. The method of claim 5, The cationization reaction reagent is a method for producing a cationic mixed polymer, characterized in that the reaction reagent containing a quaternary ammonium group. Cationic mixed polymer prepared by the method of claim 1. A papermaking additive comprising the cationic mixed polymer of claim 7. The method of claim 8, The papermaking additive is a papermaking additive, characterized in that the cationic mixed polymer is in the form of an aqueous solution in a concentration of 1-10%.