KR100201963B1 - Sizing composition for paper - Google Patents

Abstract

The present invention relates to a sizing agent composition for papermaking, and more particularly, a cationic polymer is used as a dispersant to form a protective colloid in a composition consisting of an aqueous acid solution of a ketene dimer, thereby improving storage stability and imparting self-fixing properties. The present invention relates to a papermaking size composition of a novel composition which greatly improves the storage stability at high concentration and the sizing effect after the papermaking process by increasing the reaction rate of the cellulose group with the alkyl ketene dimer.

Description

Paper Size Composition

The present invention relates to a sizing agent composition for papermaking, and more particularly, a cationic polymer is used as a dispersant to form a protective colloid in a composition consisting of an aqueous acid solution of a ketene dimer, thereby improving storage stability and imparting self-fixing properties. The present invention relates to a papermaking size composition of a novel composition which greatly improves the storage stability at high concentration and the sizing effect after the papermaking process by increasing the reaction rate of the cellulose group with the alkyl ketene dimer.

In conventional papermaking processes, so-called sizing is effectively used to provide products with stain resistance, water resistance and water resistance. This sizing is divided into so-called internal sizings that apply a sizing agent to the pulp composition during paper processing before the fibrous sheet is produced and so-called surface sizings that apply the sizing agent to the surface of the resulting fibrous sheet. Lose.

In the internal sizing, an acidic sizing method for sizing at a pH of 4.5 to 6.5 using a rosin sizing agent and aluminum sulfate is commonly used. However, in recent years, so-called neutral sizing has attracted attention. This neutral sizing can use a closed system where papermaking water is recycled, thereby saving water and using relatively low cost calcium carbonate as a filler as it produces paper at neutral or weakly alkaline at pH 6.5-9. .

As size agents today, ketene dimer compounds, substituted cyclic dicarboxylic acid anhydride compounds, copolymers of cationic monomers and hydrophobic monomers, cationic aliphatic amides and the like are used. Among them, aqueous dispersions of ketene dimer compounds are most widely used because of their excellent sizing effect.

These ketene dimers are known to react with the hydroxyl groups of cellulose molecules to impart a sizing effect to the fibers. In recent years, the size effect of the neutral paper that does not use an alarm is being highlighted.

Typically ketene dimer compounds are commercially available in the form of aqueous dispersions in which the ketene dimer is dispersed in a continuous aqueous phase with starch, in particular cationic starch. However, since ketene dimer compounds are inherently reactive with water, it is difficult to provide them as stable aqueous acid solutions. Therefore, these commonly used dispersions sometimes lose homogeneity and deposits are formed during solidification or storage, thereby losing the waterproofing effect of the post-paper sizing effect and causing the papermaking process contamination.

Thus, the concentration of ketene dimers in solutions of commercially available sizer products does not exceed up to 15%. However, such low concentrations of dispersion may provide a cause of cost increase during storage or transportation, and may also cause another problem that may not be sufficient stability even at low concentrations, which may cause user dissatisfaction.

As a conventional sizing agent composition, U.S. Patent No. 4,861,376 describes that the storage stability of the sizing agent dispersion can be improved to some extent by the addition of cationic starch and acetic acid during the preparation of the ketene dimer aqueous dispersion (sizing agent) on wax emulsion. Specifically, according to Example 1 of the patent, the viscosity of 20 cst immediately after preparation is increased to 35 cst after 5 weeks, based on 20% solids. However, even in this case, the increase in viscosity is still larger than the solid content, and the increase in size is not large because the number of particles is not large in the size agent dispersion reacting with the fibers. This seems to be due to the cationicity of the cationic starch not exceeding a certain range and not enough to generate protective colloids and to have a poor fixability to the fibers.

As another technique, according to Korean Patent Publication No. 92-6423 (Publication No. 2884), acrylamide having a terminal group treated with alkyl methane and cationic to solve the above-mentioned problems in preparing a ketene dimer composition. Copolymers of vinyl monomers were used with ketene dimer compounds. However, this composition also improved the storage stability to some extent due to the end group treatment effect, the storage stability and size performance (stock kit size of 21 sec) does not show a much superior effect compared to the existing composition.

As described above, the conventional sizing agent composition can be seen to exhibit some degree of stability and size effect, but especially at high concentrations, the storage stability is greatly degraded and the size also does not show a great effect. Furthermore, a sizing agent composition which exhibits a storage stability at a high concentration and shows an excellent size effect after papermaking has not been developed yet.

As a result, it is necessary to solve the problems such as having excellent storage stability even at high concentrations and exhibiting sufficient size under neutral papermaking conditions and problems such as water resistance in the papermaking process and water resistance in final paper products. Remained.

Therefore, in order to solve the above problems, the present invention adds acrylamide-type polymers having a specific molecular weight and charge density, which are cationic polymers, in the preparation of ketene dimer aquatic acid solution and uses anionic dispersants to interact in the emulsion system. The purpose of the present invention is to provide improved paper sizing compositions which can contribute to improved usability and post-use paper quality, while improving the storage effect at high concentrations.

The present invention relates to a paper-making size agent composition of an aqueous acid solution liquid containing acrylamide component in a ketene dimer.

a) 100 parts by weight of a ketene dimer compound represented by Formula 1

b) 3 to 10 parts by weight of acrylamide polymer containing 3 to 30 mol% of cationic monomer and 0.1 to 0.5 mol% of anionic monomer, and

c) 1 to 10 parts by weight of anionic dispersant.

Wherein R ₁ and R ₂ are the same or different hydrocarbyl groups having 10 to 20 carbon atoms, respectively.

Referring to the present invention in more detail as follows.

The present invention uses a cationic acrylamide-type polymer containing a large amount of cationic monomers compared to anionic monomers as the acrylamide component when preparing a known aqueous acid solution containing acrylamide component in a ketene dimer compound. The biggest feature is to do.

The ketene dimer compounds used in the present invention may be used alone or in combination of two or more of the compounds represented by Formula 1, in particular, R ₁ and R ₂ are the same or different hydrocarbyl group having 14 to 18 carbon atoms, respectively. Is preferable.

The polymer used in the present invention is a water-soluble or water-dispersible cationic acrylamide type polymer, which is used in an amount of 3 to 10 parts by weight based on 100 parts by weight of a ketene dimer compound. The dispersion stability is then lowered.

The main repeating unit of the cationic acrylamide type polymer used in the present invention is acrylamide or metharylamide. 3 to 30 mol% of the monomers constituting the main repeating unit are cationic monomers, wherein the cationic group is, for example, a primary, secondary or tertiary amine group, or a quaternary ammonium chloride group, specifically, acryloylmethyl ammonium Chloride or methacryloylethyltrimethyl ammonium chloride, and 0.1 to 0.5 mol% is an anionic monomer, where the anionic group is for example a carboxyl group or a sulfone group, specifically acrylic acid.

Here, if the amount of the cationic monomer in the repeating unit is greater than this, the economy is a problem, and if the amount is too small, it is not applicable as an effective protective colloid. Not good

Such cationic groups and anionic groups may be the same or used in combination with two or more different groups.

The cationic group in the acrylamide polymer of the present invention is a known method such as Hoffmann's reaction in which acrylamide-type polymer reacts with hypochlorous acid in basic, or Mannich reaction in which acrylamide-type polymer reacts with a mixture of formalin and amine. Can be introduced by.

In addition, the anionic group can be effectively introduced by acrylamide-type polymer is reacted with a derivative of hydrosulfite and formalin, or hydrolyzed for acid or base.

On the other hand, in the present invention, in addition to the cationic acrylamide type polymer as described above, an anionic dispersant is used. As the anionic dispersant, an anionic group having a carboxyl group, a sulfonic acid group, or a sulfate ester, in particular, a lignin sulfonic acid sodium sulfonate group effective.

These anionic dispersants are used to adsorb the colloid to increase the surface potential. If the amount of the anionic dispersant is less than 1 part by weight based on 100 parts by weight of the ketene dimer compound, a sufficient surface potential is obtained and the amount is greater than 10 parts by weight. If used, the ionic strength of the solvent is too large, which may cause aggregation, which is not preferable.

The size composition according to the invention can be prepared by known methods. For example, a ketene dimer compound, a cationic acrylamide type polymer, and an anionic dispersant may be mixed in an aqueous medium of deionized water, but higher than the melting point of the ketene dimer compound. 70 It is prepared by mixing using a stirrer, predispersion using a homogenizer, and then uniformly dispersing the mixture using a high pressure homogenizer. In this case, the cationic polymer used acts as a protective colloid, and the anionic dispersant is adsorbed on the surface of the colloid to exhibit the property of preventing aggregation.

In addition, the water used with the above components may be, for example, 300 deionized water based on 100 parts by weight of the ketene dimer compound. Since it is used in 500 parts by weight, excessive amounts of water are not economical, and small amounts result in storage stability.

As such, the papermaking size composition prepared according to the present invention is generally 20 Have a concentration of 30% by weight and have a particle diameter of 5 Size composition (15% by weight, particle diameter 7) consisting of a dispersion of conventional ketene dimer compounds as less than It has been found that the dispersion concentration of the sizing agent composition shows satisfactory storage stability even at up to 30% by weight.

In addition, when used in the papermaking process, for example, the amount of 0.2% of the dry weight of the non-volatile standard pulp, which is added just before the head box, results in an excellent sizing effect even at low concentrations.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1

[Stage 1 ]

250 A four-necked flask equipped with a stirrer, thermometer, circulating condenser and nitrogen inlet was installed, followed by 123.2 g of deionized water, 23.8 g of 50% aqueous acrylamide (AM), 1.05 g of acrylonitrile, and 0.7% aqueous 5% acrylic acid (AA). g and 1.21 g of acryloylethyltrimethyl ammonium chloride (Q1) 80% aqueous solution were added. PH 4.0 with 1N aqueous sulfuric acid solution After adjusting to 5.0, the mixture is stirred while nitrogen is introduced to remove oxygen from the flask. The reaction mixture is then 55 Heated to 0.2 g of 10% aqueous solution of ammonium persulfate and 0.3 g of 10% aqueous solution of sodium hydrosulfite, and then the temperature of the reaction mixture was Raise up. The reaction mixture continues to react for 90 minutes at the same temperature and then slowly cools to room temperature. The polymer solution obtained contains 10.4% of nonvolatile matter, 25 Brookfield viscometer at 60 rpm was found to have a viscosity of 460 cps.

[Step 2]

100 parts of a ketene dimer compound and 80 parts of the polymer solution obtained in step 1 and 4 parts of sodium lignin sulfonate as anionic dispersant, and 182 parts of deionized water were mixed. Heated and predispersed until complete mixing with a homogeneous mixer. Shear pressure of 300 kg / Under two passes through a high pressure homogenizer under complete dispersion and then through a screen of 325 mesh. The nonvolatile content of this composition is 30.6% and 25 . A Brookfield viscometer at 60 rpm was shown to have a viscosity of 12.3 cps. 25 This composition The change in viscosity over time is measured as a measure of storage stability during storage for one month at.

Example 2 4]

In step 1 of Example 1, the amount of the acrylamide 50% aqueous solution and the acryloylethyltrimethyl ammonium chloride (Q1) 80% aqueous solution was changed as shown in Table 1, and the same procedure as in Example 1 was repeated. The physical properties of the obtained aqueous polymer solution are shown in Table 1.

Comparative Example 1 2]

In the first step of Example 1, the amount of the acrylamide 50% aqueous solution and the acryloylethyltrimethyl ammonium chloride (Q1) 80% aqueous solution was changed as shown in Table 1 outside the range set forth in the present invention and the above Example The same procedure as 1 was repeated. The physical properties of the obtained aqueous polymer solution are shown in Table 1.

Example 5 6]

In order to change the cationic group in the first step of Example 1, using 80% aqueous solution of methacryloylethyltrimethyl ammonium chloride (Q2) instead of 80% aqueous solution of acryloylethyltrimethyl ammonium chloride (Q1) Was changed as shown in Table 2 and the same procedure as in Example 1 was repeated. Physical properties of the obtained aqueous polymer solution are shown in Table 2 below.

Example 7

In step 1 of Example 1, maleic acid (M) was used instead of acrylic acid to change the anionic group, and the same process as in Example 1 was repeated. Physical properties of the obtained aqueous polymer solution are shown in Table 2 below.

Comparative Example 3

In order to change the proportion of the anionic group in step 1 of Example 1, acrylic acid was used outside the range shown in the present invention as shown in Table 2, and the same procedure as in Example 1 was repeated. Physical properties of the obtained aqueous solution are shown in Table 2 below.

Example 8 9]

In step 2 of Example 1, the amount of the anionic dispersant sodium lignin sulfonate was changed as shown in Table 3 below, and the same procedure as in Example 1 was repeated.

Comparative Example 4 5]

As two commercially available products, Expe1-200D manufactured by Taekwang Chemical Co., Ltd. and Hercon-79 manufactured by Heolyul Lee, Korea were used as Comparative Examples 4 and 5.

Experimental Example

Example 1 9 and Comparative Example 1 The storage stability and sizing effect of the sizing agent composition according to 5 were measured and shown in Table 3. The storage stability was 25 It is represented by the viscosity after storage for 1 month at, and the lower the viscosity, the more stable. The papermaking for measuring the sizing effect followed the following procedure. First, a 2.5% pulp slurry (90% bleached pulp and 10% soft bleached pulp, Canadian Standard Yeosu 50 0.3% of cationic starch (Suncaster Co., Ltd. of Samyang Genex) was added and the mixture was stirred for 5 minutes. The slurry was then diluted to 0.5% and Example 1 above. 9 and Comparative Example 1 The sizing agent composition according to 5 was added so that the nonvolatile components became 0.2% of the dry amount of the pulp. The mixture was stirred for 1 minute and then weighed 70 g / Phosphorus wetlands were prepared at pH 7. Pressed at 4 atmospheres for 5 minutes, and then It dried for 1 minute, and the stick kit size of the obtained paper was also measured. The rate of addition of all chemicals is based on the weight of the completely dried pulp. The results are shown in Table 3 below.

Co., Ltd. * Storage stability: Increased from the initial state after one month

As can be seen in Table 3 Example 1 according to the present invention In case of 9, the increase in viscosity was small and the size was excellent, whereas Comparative Example 1 3 showed a viscosity increase of 40 cps or more in one month. 5 increased more than 50cps in a month.

Therefore, in the case of the present invention it can be confirmed that the storage stability is excellent even at a high concentration compared to the comparative example, the sizing effect is significantly improved even in the input of the same solids.

Claims (1)

The present invention provides a papermaking size composition for an aqueous acid solution containing an amphoteric acrylamide component and an anionic dispersant in a ketene dimer, comprising: a) 100 parts by weight of a ketene dimer compound represented by the following Formula 1 and b) cationic Acrylamide type polymer containing 3 to 30 mol% of acryloyltrimethyl ammonium chloride or methacryloylethyltrimethyl ammonium chloride as an monomer and 0.1 to 0.5 mol 5% of acrylic acid or maleic acid as an anionic monomer (C) 1 to 10 parts by weight of sodium lignin sulfonate as an anionic dispersant. [Formula 1] Wherein R ₁ and R ₂ are the same or different hydrocarbyl groups having 10 to 20 carbon atoms, respectively.