JPH02127594A - Sizing of papermaking raw material using substituted succinic anhydride - Google Patents

Abstract

PURPOSE:To accomplish marked improvement of sizing effect of papermaking raw material as well as cost reduction of the sizing by using a size-emulsified liquid prepared by blending a substituted succinic anhydride as sizing agent with each specified surfactant and cationic starch. CONSTITUTION:A papermaking raw material is sized using a size-emulsified liquid comprising (A) a substituted succinic anhydride, (B) an anionic surfactant, and (C) a cationic starch >=0.02 in substitution degree prepared by cationizing raw starch followed by no washing process. The component B is pref. a polyoxyalkylene alkyl ether phosphoric ester. In preparing the component C, it is suggested that rootstock starch such as tapioca be used as the raw starch and a quanternary ammonium salt be used as cationizing agent.

Description

Detailed Description of the Invention [Industrial Application Field 1] The present invention relates to a sizing method using substituted succinic anhydride as a sizing agent, and more specifically to a sizing method using substituted succinic anhydride, a surfactant, and The object of the present invention is to provide a novel sizing method that can significantly improve the sizing effect exerted by a sizing emulsion containing cationic starch.

[Prior art 1] A sizing method using substituted succinic anhydride as a sizing agent is well known, and cationic starch ( Japanese Patent Publication No. 39-2305, Japanese Patent Publication No. 58-1973
97), cationic or amphoteric synthetic polymer substances (JP-A-58-45730, JP-A-58-12)
Publication No. 0897), various surfactant substances (Special Publication No. 1989-
36044, JP 58-87397, JP 58-220897, JP 59-4749
No. 8, JP-A-59-187696, JP-A-6
0-28598) and the like have been proposed. The cationic starch is generally used after raw starch is cationized using a cationizing agent, purified and dried through a washing process, and then gelatinized and diluted.

[Problem to be solved by the invention] In recent years, with the increase in neutral papermaking, the amount of cationic starch used as a papermaking chemical has increased, and it has come to occupy a large part of the cost of paper. In some cases, cationic starch is also produced for down. In this case, in the step of cationizing the raw starch using a cationizing agent, a washing step is rarely performed after the cationization because there is a lot of waste in the process.

These cationic starches are sometimes called self-modified cationic starches to distinguish them from commercially available purified cationic starches. Since such self-modified cationic starch is not washed after cationization as described above, it contains residues of cationizing agent, hydrolyzate, NaCl2. Na, So
The resulting size liquid is alkaline because it is contaminated with salts such as No. 4 and the cationization reaction is carried out on the alkaline side. Due to these characteristics, such self-modified cationic starch can be used as a paper strength enhancer, but cannot be used as a dispersant when dispersing substituted succinic anhydride in water to obtain an aqueous emulsion. It has been.

In fact, when the present inventors emulsified a commercially available substituted succinic anhydride composition using the above self-modified cationic starch and investigated the size performance of the resulting aqueous emulsion, they found that
It was confirmed that the comparative size performance was significantly inferior when purified cationic starch was used. Further, when this aqueous emulsion was observed under a microscope, it was confirmed that the particles of the substituted succinic anhydride were not uniformly dispersed in the water, and that the particles were agglomerated. This agglomeration of particles not only reduces the uniformity of sizing, but also greatly affects staining during the papermaking process due to hydrolysis of substituted succinic anhydride.

In addition to the above-mentioned self-modified cationic starch, recently, with the main purpose of reducing production costs, raw starch is subjected to cationization reaction in powder form without being dispersed in water, and it is also available for use as is without washing. A so-called dry reaction method cationic starch is also being considered, but since this type of starch also contains a significant amount of impurities, when used as a sizing emulsifier, it must be treated in the same way as self-modified cationic starch. A problem has arisen.

[Means for Solving the Problems] The present inventors solved the problems in the above-mentioned conventional techniques with the aim of improving the sizing performance of a size emulsion comprising a substituted succinic anhydride, a surfactant, and a cationic starch. As a result of intensive studies in view of the The inventors have discovered that the sizing performance is improved compared to when starch is used, leading to the present invention.

That is, the present invention provides a method for sizing papermaking raw materials using a size emulsion containing a substituted succinic anhydride, a surfactant, and a cationic starch, in which an anionic surfactant is used as the surfactant, and an anionic surfactant is used as the surfactant. Use cationic starch that is produced without a washing step after cationization in the process of cationizing raw starch using a cationizing agent, and whose degree of substitution is 0.02 or more. This is a method for sizing special paper raw materials.

In the sizing method of the present invention having the above configuration, as the substituted succinic anhydride used as a sizing agent, any of the conventionally known substituted succinic anhydrides as a sizing agent can be used, but specifically, Substituted succinic anhydride having a hydrophobic hydrocarbon having 12 to 36 carbon atoms, such as an alkyl group or an alkenyl group, preferably JP-A-59-17
9898; the proportion of olefins having 14 to 36 carbon atoms and 21 bonds at the 2nd, 3rd and 4th positions is 10 to 65%, and the total thereof is 70 mol% Most preferred is the use of substituted succinic anhydrides having alkenyl groups as described above.

This substituted succinic anhydride can generally be easily produced by addition reaction of an olefin with maleic anhydride, such as an α-olefin, an internal olefin, or a mixture thereof having the corresponding number of carbon atoms.

The surfactant used as a dispersant for the substituted succinic anhydride of the present invention is mixed in advance with the substituted succinic anhydride before being mixed with the cationic starch, and is an anionic surfactant. It is essential that there be.

The anionic surfactant includes: 1) polyoxyalkylene alkyl ether phosphate or its salt 2) polyoxyalkylene alkyl aryl ether phosphate or its salt 3) polyoxyalkylene aralkyl aryl ether phosphate or its salt Salt 4) Polyoxyalkylene alkyl aryl ether sulfate or its salt 5) Polyoxyalkylene alkylaryl ether sulfate or its salt 6) Polyoxyalkylene alkylaryl ether sulfate or its salt (blank below) 7) Represented by the following Polyoxyalkylene derivative R H where R: alkyl group or alkenyl group having 8 or more carbon atoms R': hydrophobic group A: bond between hydrophobic group and polyoxyalkylene group X: hydrogen or methyl group n, m: 21 Each of the above integers is represented.

etc., but any surfactant can be used as a dispersant for the substituted succinic anhydride of the present invention. Preferably, when using polyoxyalkylene alkyl ether phosphates, polyoxyalkylene alkyl aryl ether phosphates, or polyoxyalkylene aralkyl aryl ether phosphates, or mixtures of these phosphates, most substituted succinic acid esters are preferred. Enhances the size performance of anhydrous materials.

The cationic starch used to stabilize the substituted succinic anhydride is made from tapioca or potato, and
A cationic compound having an It conversion of 0°02 or more by introducing one or more basic nitrogens selected from cationizing agents consisting of primary, secondary, and tertiary amine groups and quaternary ammonium groups. It is a starch that is used after gelatinization and dilution without a washing step after the cationization reaction in the process of producing cationic starch.

The above method for producing cationic starch includes: I) adding a cationizing agent to an aqueous dispersion of raw starch, reacting at a low temperature for several hours, and then heating and gelatinizing; 2) adding cations to an aqueous dispersion of jKfi4 starch; A method in which a cationizing agent is added and the cationization reaction and gelatinization are carried out simultaneously at high temperature and in a short time.3) A method in which the raw starch is gelatinized in advance, and then a cationizing agent is added and the reaction is carried out at a high temperature.4) A method in which the raw starch is made into an aqueous solution. There are methods in which a cationizing agent is added and the reaction is carried out in powder form without forming a dispersion, and any of these reactions can be used as the method for producing the cationic starch of the present invention. It is important to adjust the pH of these pastes to a range of about 5 to 8 before using them to make them weakly acidic to neutral. This is because when the pH exceeds 8 and becomes alkaline, the hydrolysis of substituted succinic anhydride is accelerated and the desired effect cannot be obtained, and when the pH becomes strongly acidic below 5, the starch itself decomposes and the starch molecules This is because the molecular weight of the paper may decrease, which may adversely affect the yield of paper stock. Moreover, the effect is greatest when the basic nitrogen atom is a nitrogen atom formed by a quaternary ammonium group.

It is essential that the degree of substitution in cationic starch is 0.02 or more. This is because if the degree of substitution is less than 0.02, the desired size effect will not be exhibited, and the degree of substitution is particularly preferably 0.03 or more. On the other hand, although the upper limit of the degree of substitution is not particularly limited, it is very costly to produce a degree of substitution exceeding 0.06, and if the degree of cationization is too excessive, the yield of paper stock will deteriorate. So I don't like it. Therefore, the preferred range of the degree of substitution in cationic starch is 0.03 to 0.06, and cationic starch with a degree of substitution within this range significantly improves the size effect in combination with anionic colloidal silicic acid. .

It is essential that the raw material starch is from underground sources such as tapioca and potato; cationic starches obtained from other above-ground starches such as corn and wheat cannot improve size performance. Confirmed.

The ratio of the substituted succinic anhydride and the anionic surfactant in the aqueous emulsion of the substituted succinic anhydride is 70 to 99.9% by weight of the substituted succinic anhydride to 0.9% by weight of the anionic surfactant. 1 to 30% by weight, preferably 0.1 to 10% by weight of the anionic surfactant to 90 to 99.9% by weight of the substituted succinic anhydride, prepared by premixing. It is desirable to mix it with cationic starch.

The ratio of the substituted succinic anhydride and the cationic starch in the aqueous emulsion of the substituted succinic anhydride is 0.5 to 3 parts by weight of the cationic starch to 1 part by weight of the substituted succinic anhydride.
0 parts by weight, preferably about 1 to IO parts by weight, in which fine particles of substituted succinic anhydride and anionic surfactant are dispersed and stabilized in the aqueous solution of cationic starch. This aqueous emulsion containing substituted succinic anhydride, anionic surfactant, and cationic starch is prepared by adding substituted succinic anhydride and anionic surfactant to an aqueous solution in which cationic starch is dissolved in advance. It can be easily obtained by mixing a mixture and stirring and homogenizing as necessary.

In the sizing method of the present invention, it is preferable to use colloidal silicic acid as a retention aid.

Retention improvers are added to papermaking raw materials in order to improve the retention of fine fiber raw materials and fillers in papermaking raw materials in the papermaking process, such as cationic starch, cationic polyacrylamide, cationic polyethylene. Polymeric substances such as imines are well known as general retention improvers, but recently papermaking methods have been used to significantly improve retention by using cationic starch or cationic or amphoteric guar gum in combination with colloidal silicic acid. has been proposed (Japanese Unexamined Patent Publication No. 57-51900, Japanese Patent Publication No. 58-502)
Publication No. 00). These retention improvers generally not only improve the retention of fine fiber raw materials and fillers in papermaking raw materials, but can also improve the retention of sizing agents, so they can be used to efficiently utilize sizing. The selection of retention aid is also important. As a result of various studies conducted by the present inventors from this point of view, it has been found that it is preferable to use colloidal silicic acid as described above. This colloidal silicic acid is about 100
It is desirable to have a surface area of ˜lo00 m”/g,
Preferably, the surface area is about 300 to 700 m''/H.The particle size is 60 nm or less, preferably 20 nm or less, and more preferably about 1 =
Adjust to a range of l On m. (Surface area is approximately 550
The particle size of colloidal silicic acid particles of m”/g is approximately 5.5n.
It is m. ) The papermaking raw material used in the sizing method of the present invention contains 0.03 to 3% by weight of substituted succinic anhydride, 0.03 to 3% by weight of colloidal silicic acid, and o by weight, based on the dry weight of the pulp in the pulp slurry. It is preferable that the amount of the substituted succinic anhydride and colloidal silicic acid is contained in the amount of about 0.05% by weight. It goes without saying that a pulp slurry to which appropriate additives (such as fluorescent dyes, fillers, paper strength enhancers, etc.) may be used is used.

The sizing method of the present invention having the above-described structure can be applied to all papermaking methods that involve papermaking from papermaking raw materials regardless of the type of pulp, but is particularly applicable to fillers made of calcium carbonate. A remarkable effect can be obtained in the case of a so-called neutral or alkaline paper manufacturing method in which .

[Operation] In a method for sizing papermaking raw materials using a size emulsion containing substituted succinic anhydride, a surfactant, and cationic starch, a step of cationizing raw material starch as cationic starch using a cationizing agent. When using cationic starch produced without a washing step after cationization, the size effect decreases when a nonionic surfactant is used as the surfactant, whereas anionic starch The size effect is significantly improved by using the agent. As for this principle mechanism, no clear conclusion has yet been reached through research by the present inventors.

However, the dispersed particle size of the substituted succinic anhydride using an anionic surfactant and the cationic starch as the dispersant is different from that of the substituted succinic anhydride using the nonionic surfactant and the cationic starch as the dispersant. Compared to the aqueous emulsion of
It has been confirmed that when the dispersion conditions are the same, the particle size distribution of the dispersed particles is fine and uniform, and this is presumed to have a large influence on the improvement of the size effect.

[Examples] Example 1 1) Production of cationic starch Acetylated tapioca starch with a degree of substitution of 0.03 [Falazim T: manufactured by Matsutani Chemical Industry Co., Ltd., 196 parts by weight,
The cationizing agent [NT
-21: Manufactured by Toho Chemical Industry Co., Ltd.] Cationic starch obtained by reacting 6 parts by weight under alkaline conditions for 5 hours was neutralized with acid without dehydration, washing, or purification, and diluted after heating and gelatinization. A 1% by weight aqueous solution was prepared. At this time, obtained l;
The degree of cationic group substitution of cationic starch is 0.04,
The pH of the aqueous solution was 6.3.

2) Preparation of aqueous emulsion of substituted succinic anhydride Substituted succinic anhydride (alkenyl substituent having 1 carbon number
5 to 18) (hereinafter abbreviated as rASAJ) 95
% by weight and 5% by weight of polyoxyethylene nonyl phenyl ether phosphoric acid ester (9 moles of oxyethylene units in the polyoxyethylene group) was mixed with a Venturi type emulsifier at an inlet pressure of 4.0 Kg/ c.
At m', dispersion and emulsification were performed to obtain an aqueous emulsion of ASA.

3) Paper manufacturing method Beaten flow pulp (L-BKP: Beating degree C3F360cc)
25% by weight of ground calcium carbonate (
After adding and mixing the ASA aqueous emulsion obtained in 2) above, the ASA and anionic surfactant were used as a premixture of 0.21% of the ASA and anionic surfactant. [An amount equivalent to % by weight was added and thoroughly mixed and dispersed. Next, 0.6% by weight of the cationic starch aqueous solution obtained in the above section 1) was added as cationic starch, and after mixing, colloidal silicic acid [particle size 7-9nmlO, '08% by weight (S
in2 conversion) and paper was made in the conventional manner using a TAPPI standard sheet machine to obtain a paper basis weight of 80 g/m”
I obtained handmade paper.

Example 2 A cationization reaction was carried out using potato starch as the raw material for the cationic starch in section l) of Example 1, and a 1% by weight aqueous solution of cationic potato starch with a degree of cationic group substitution of 0.04 (at this time, The pH of the cationic starch aqueous solution is 6.
．． A handmade paper was obtained by repeating the same procedure as in Example 1 except for using 0).

Example 3 The reaction under alkaline conditions in Section 1) of Example 1 was carried out at high temperature for a short time, and the cationization reaction and gelatinization were carried out simultaneously.
After gelatinization, it was neutralized with acid and further diluted to a 1% by weight aqueous solution (the cationic group substitution degree of the cationic starch obtained at this time was 0.0).
4 and the pH of the aqueous solution was 6.5), the same procedure as in Example 1 was repeated to obtain handmade paper.

Example 4 As the surfactant used as a dispersant for ASA in Section 2) of Example 1, a premix of 5% by weight of polyoxydiethylene distyrenated phenol ether phosphate is used with respect to 95% by weight of ASA. Except for this, the same procedure as in Example 1 was repeated to obtain handmade paper.

Comparative Example 1 Example except that in place of the cationic starch in Section 1) of Example 1, commercially available cationic tapioca starch with a degree of cationic group substitution of 0.04, which had undergone a washing and drying process after the cationization reaction, was used. The same procedure as in 1 was repeated to obtain handmade paper for comparison.

The pH of the cationic starch aqueous solution obtained at this time was 70.

Comparative Example 2 The same procedure as in Example 1 was repeated, except that the cationic starch in Section 1) of Example 1 was heated and gelatinized without being neutralized with acid after production, and used as a 1% by weight aqueous solution after dilution. A handmade paper was obtained for comparison. The pH of the cationic starch aqueous solution obtained at this time was 1O65. ) Comparative Example 3 Instead of the surfactant used as a dispersant for ASA in Section 2) of Example 1, a nonionic one was used as a dispersant for ASA9.
A handmade paper for comparison was obtained by repeating the same procedure as in Example 1, except using 5% by weight as a premix for 5% by weight.

Comparative Example 4 A cationization reaction was carried out using corn starch as the raw material for the cationic starch in Section 1) of Example 1, and a 1% by weight aqueous solution of cationic corn starch with a degree of cationic group substitution of 0.04 (obtained at this time) was prepared. The pH of the cationic starch aqueous solution is 6.
．． A hand-made paper for comparison was obtained by repeating the same procedure as in Example 1, except for using 3).

Comparative Example 5 In place of the cationic starch in item l) of Example 1, commercially available cationic tapioca starch with a degree of cationic group substitution of 0.04 that had undergone a washing and drying process after the cationization reaction (the pH of the 1% aqueous solution was 7.0) was used, and a nonionic surfactant used as a dispersant for ASA in Section 2) of Example 1 was used as a premix of 5 it amount % with respect to 95 weight % ASA. A handmade paper for comparison was obtained by repeating the same procedure as in Example 1 except for using the following.

Comparative Example 6 In the production of cationic starch in Section 1) of Example 1, the amount of other cationic agents used was reduced from 6 parts by weight to 2 parts by weight to obtain cationic starch with a degree of cationic group substitution of 0.015, Except for using this, the same procedure as in Example 1 was repeated to obtain handmade paper for comparison. The pH of the cationic starch aqueous solution I obtained at this time was 6.8.

Dispersed particle diameter of ASA in the ASA aqueous emulsions used in the above examples and comparative examples, Steckigt sizing degree of each obtained handmade paper (according to JISP-8122)
, and the dispersion state of the dispersed particles of ASA are shown in Table 1.

Table 1 As is clear from the results shown in Table 1, starch was produced without a washing step after cationization in the process of cationizing raw starch using a cationizing agent, and the degree of substitution was low. Examples 1 to 1 of the present invention in which an ASA aqueous emulsion was prepared using a cationic starch having a molecular weight of 0.02 or more and an anionic surfactant as a dispersant.
In all of No. 4, the dispersion state of the ASA aqueous emulsion was good and the size effect of the manufactured handmade paper was excellent. On the other hand, in Comparative Examples 1 to 6 that did not meet these conditions, sufficient size effects could not be obtained.

[Effect of the invention 1] In the sizing method of the present invention, in the preparation of an aqueous emulsion of substituted succinic anhydride, cationic starch is washed after cationization in the step of cationizing raw starch using a cationizing agent. When cationic starch (a) and anionic surfactant (b) produced without any process are used as dispersants, papermaking with excellent size effects can be obtained.

Therefore, in the sizing method of the present invention, cationic starch produced without a washing process when cationizing raw starch can be effectively used, resulting in a significant reduction in the cost of cationic starch. Not only can this be achieved, but also a significant reduction in sizing costs can be achieved due to the improved size effect. Furthermore, since the aqueous emulsion of substituted succinic anhydride has high stability, it reduces troubles during papermaking operations caused by hydrolysis of substituted succinic anhydride, and has extremely useful industrial value. It is something.

Claims (5)

[Claims] (1) In a method of sizing papermaking raw materials using a size emulsion containing a substituted succinic anhydride, a surfactant, and a cationic starch, an anionic surfactant is used as the surfactant, and the cationic starch is As starch, use cationic starch that is produced without a washing step after cationization in the process of cationizing raw starch using a cationizing agent, and whose degree of substitution is 0.02 or more. Characteristic method for sizing papermaking raw materials. (2) The surfactant is polyoxyalkylene alkyl ether phosphate (or its salt) or polyoxyalkylene alkylaryl ether phosphate (
2. The sizing method according to claim 1, wherein the sizing method is a polyoxyalkylene aralkylaryl ether phosphate (or a salt thereof), or a mixture of these phosphoric esters (or a salt thereof). (3) The sizing method according to claim 1 or 2, wherein the cationic starch is adjusted in advance to have a pH in the range of 5 to 8. (4) The sizing method according to any one of claims 1 to 3, wherein the cationic starch is made from tapioca or potato. (5) The sizing method according to any one of claims 1 to 4, characterized in that colloidal silicic acid is used in combination as a retention aid.