JPH0215677B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a sizing agent composition for paper manufacturing. More specifically, the present invention relates to a new paper-making sizing composition that can be used in a neutral or alkaline pH range of papermaking water and has good dispersion stability of ketene dimer fine particles. [Prior Art] Rosin or reinforced rosin (maleated rosin) has been widely used as a sizing agent for paper manufacturing. However, this rosin-based sizing agent has many problems because it requires fixing with aluminum sulfate. In other words, fixing with aluminum sulfate can cause serious damage to the paper-making machine and make the paper unsuitable for printing, as the PH of the water used during paper-making is low (acidic), and there is also a risk of discoloration due to long-term storage of the paper and a burden on wastewater treatment. Shortcomings such as heavy weight have been pointed out. Also, when calcium carbonate is used as a filler,
Rosin-based sizing agents cannot be used because calcium carbonate decomposes in acidic solutions. Calcium carbonate is cheaper than talc, is one of the richest resources in Japan, is easily available, and has a high degree of whiteness, so it is known to be effective when used as a material for paper. At present, its use is extremely limited due to these reasons. Therefore, it is desired to develop a neutral paper sizing agent that overcomes the above-mentioned drawbacks, does not deteriorate paper quality, reduces wastewater treatment, and allows the use of calcium carbonate. In recent years, various neutral sizing agents have been proposed to achieve this purpose, but among them, a sizing agent in which a ketene dimer is colloidally dispersed in water is considered to be the most promising, and has been patented numerous times. has been filed. [Problems to be Solved by the Invention] However, despite many research efforts, it has been found that ketene dimer-based sizing agents take time to develop their size effects, and that ketene dimer particles cannot be stably dispersed. It has the disadvantage that it is difficult to maintain it as a liquid. Generally, when a ketene dimer-based sizing agent is used, the sizing performance immediately after papermaking is poor, and it is said that it takes time to obtain sufficient sizing performance compared to the amount of sizing agent used. This problem is generally pointed out as a poor rise in the size effect, but it is easy to imagine that this poor rise leads to the following drawbacks. That is, it is difficult to control the quality of paper that requires a high size effect in the final product, such as writing paper or milk cartons. Furthermore, in order to obtain a high size effect, the paper must be shipped after several days have elapsed, but it goes without saying that storage until shipping increases the cost of paper. On the other hand, in the case of coated paper, an internal sizing agent is used to control the amount of liquid absorbed during the coating process. Currently, coating is often carried out continuously from paper making, and in this case,
If the size effect does not appear immediately after the wet paper is dried (immediately after paper making), it is of no use at all. Ketene dimer-based sizing agents can be used in the neutral range. Size effect can be seen with low addition amount. Despite its excellent performance, such as the ability to produce high-size paper, its use is currently extremely limited due to the above-mentioned reasons. It goes without saying that sufficient consideration must also be given to the dispersion stability, storage stability, and especially mechanical stability of the sizing composition. Mechanical stability refers to stability against external mechanical shear during transport of the sizing agent or during use of the sizing agent, and is particularly important among dispersion stability. However, such dispersion stabilizers can be improved by lowering the concentration of active ingredient in the sizing composition. However, products with low concentrations of active ingredients require high costs for transportation, filling, etc., and require large-capacity containers for storage, making them extremely uneconomical. Therefore, in the paper manufacturing industry, there is a desire to develop a sizing agent that has a high effective concentration, good dispersion stability, and a good rise in size performance, and has excellent size performance effects. [Means for Solving the Problems] In view of the above-mentioned circumstances, the present inventors have developed an aqueous dispersion with a high concentration of active ingredients and good dispersion stability and storage stability, especially in terms of size performance. As a result of intensive research to find a ketene dimer-based paper sizing agent composition that has good sizing properties and excellent size performance effects, we found that by mixing a certain compound with ketene dimer, the concentration of the active ingredient is high. The present inventors have discovered that it is possible to obtain a sizing agent composition that has good dispersion stability even in the above range, has a good rise in size performance, and has excellent size performance effects, and has completed the present invention. That is, the present invention provides an aqueous dispersion in which a mixture of a ketene dimer represented by the following general formula (1) and an ester compound represented by the general formula (2) in a weight ratio of 99.8/0.2 to 80/20 is dispersed in water. This relates to a paper sizing agent composition characterized by comprising: (In the formula, R ₁ and R ₂ are alkyl groups having 8 to 24 carbon atoms,
It is an alkenyl group or an aryl group. ) (In the formula, R ₃ is an alkyl group or alkenyl group having 1 to 20 carbon atoms, AO is an alkylene oxide having 2 to 4 carbon atoms, L is 0 to 5, m is 0 to 200, n
is an integer from 1 to 4. ) The ketene dimer constituting the present invention is disclosed in JP-A-Sho
48-48702, JP 52-110906, JP 52-118010, JP 55-98997,
Any of the known ketene dimers disclosed in JP-A-55-116898, JP-A-60-99097, etc. can be used. In the ketene dimer shown in the above general formula (1),
R ₁ and R ₂ each have 8 to 24 carbon atoms, preferably 12
-22 alkyl, alkenyl or aryl groups. Specific examples of the groups represented by R ₁ and R ₂ include alkyl groups such as octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, and eicosyl groups, octenyl, decenyl, dodecenyl, tetradecenyl, hexadecenyl, octadecenyl, and eicosenyl groups. Examples include alkenyl groups such as, aryl groups such as octylphenyl, nonylphenyl, and dodecylphenyl groups.
Among these, an alkyl group is most preferred, but the ketene dimer is not limited to one type alone, and may be a mixture of two or more types. In order to obtain the ketene dimer represented by the above general formula (1) according to the present invention, for example, a raw fatty acid mixture is reacted with phosphorus trichloride to obtain a fatty acid chloride, and then 3
A known method for carrying out a dehydrochlorination reaction in the presence of a grade amine catalyst may be applied. General formula that is another component constituting the present invention
In the ester compound represented by (2), R ₃ represents an alkyl group or alkenyl group having 1 to 20 carbon atoms, preferably 4 to 18 carbon atoms. Specific examples of the group represented by R ₃ include alkyl groups such as butyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, butenyl, octenyl, decenyl, dodecenyl, tetradecenyl,
Examples include alkenyl groups such as hexadecenyl and octadecenyl groups. AO represents alkylene oxide having 2 to 4 carbon atoms, specifically ethylene oxide, propylene oxide, and butylene oxide. Of course, a mixture thereof may also be used. Also, unless L is an integer of 0 to 5, m is 0 to 200, and n is an integer of 1 to 4, a paper sizing composition with good dispersion stability and rise cannot be obtained. That is, the ester compound represented by the general formula (2) is a monocyclic carboxylic acid ester, and examples of the monocyclic carboxylic acid include phenylacetic acid, benzoic acid, phthalic acid, trimellitic acid, and pyromellitic acid. . Further, the present ester compound may be a partial ester. Furthermore, the ratio of acidification of the ketene dimer represented by general formula (1) and the ester compound represented by general formula (2) is important, and if the weight ratio is greater than 99.8/0.2, the dispersion stability will be significantly reduced. When the weight ratio worsens and becomes smaller than 80/20, a phenomenon such as poor start-up is observed, and the weight ratio is 99.8/0.2 to 80/20.
must be within the range. To obtain the sizing composition of the present invention, first the ketene dimer is melted at a temperature equal to or higher than its melting point, and the ester compound of the present invention is dissolved therein. Next, this mixture is mixed and dispersed in pre-heated water while maintaining its molten state.
The temperature during this dispersion is below 100℃, preferably 80℃
The following is desirable. At too high a temperature, the ketene dimer may react with water to give a reaction product with no size effect. Further, during this mixing and dispersion, a suitable emulsifier or dispersant is required, and any known emulsifier or dispersant for ketene dimer can be used as the dispersant. That is, they include various nonionic and cationic surfactants and dispersants, and preferred examples of these include the following compounds. Examples of nonionic surfactants and dispersants include polyethylene oxide adducts of higher alcohols or fatty acids having 8 to 18 carbon atoms, and polyethylene oxide adducts of alkylphenols such as octylphenol and nonylphenol (Oil Chemistry, Chapter 10).
Vol., No. 5, p. 282), and block or random adducts of polypropylene oxide and polyethylene oxide of these higher alcohols, fatty acids, and alkyl phenols (JP-A-50-53608,
(Japanese Patent Publication No. 55-37639), nonionic polymers such as polyvinyl alcohol and oxidized starch (Japanese Patent Application Laid-open No. 132799/1982). Examples of cationic dispersants include cationic starch, epihalohydrin-modified polyalkylene polyamides (Japanese Unexamined Patent Publication No. 48-48702), polyethyleneimine, polyvinylpyridine, cationic polyurethane resins (Japanese Unexamined Patent Publication No. 132799-1980), etc. ), cationic vinyl copolymers (JP-A-60-99097, JP-A-60-104599, JP-A-60-219245)
(Japanese Patent Application Laid-Open No. 60-220137). In addition, as anionic dispersants, naphthalene sulfonic acid soda formaldehyde condensate and lignin sulfonic acid sodium (Japanese Patent Application Laid-Open No. 116898/1983)
etc. can be exemplified. Among these, cationic dispersants are most preferred. The amount of these emulsifiers and dispersants added is 5 to 70% by weight, preferably 10 to 40% by weight, based on the mixture of ketene dimer and ester compound.
If the amount of the dispersant added is less than this, the stability of the sizing agent dispersion liquid will be poor, and if it is added in an excessively large amount, the sizing effect will be reduced, which is not preferable. In order to use the sizing agent of the present invention with good yield, it is effective to use a fixing agent, and a cationic polymer is preferable as the fixing agent. Preferred examples of cationic polymers used as fixing agents include cationized starch, cationized cellulose, polyamide polymers, polyethyleneimine, polyvinylpyridine and its quaternized products, polydimethylaminoethyl methacrylate and its quaternized products, and polydiethylamino. Examples include ethyl methacrylate and its quaternized products, and copolymers of these cationic monomers and acrylamide. In practicing the present invention, the size composition of the present invention is added as a solids content of 0.01 to 2% by weight, preferably 0.05 to 1% by weight, based on the weight of the bulb. It goes without saying that the level of addition of these sizing agents can be adjusted depending on the sizing required for the target paper. As already mentioned, the sizing agent composition of the present invention is used in the form of being dispersed in water, and the particle size of the sizing agent particles dispersed in water is 5 microns or less,
Preferably, it is 1 micron or less. If the particle size is larger than 5 microns, the stability of the dispersion may be impaired or the size effect may be poor. A homomixer, an ultrasonic emulsifier, a high-pressure discharge type homogenizer, etc. can be used to disperse the sizing agent particles. [Effects of the Invention] The sizing agent composition of the present invention has good dispersion stability, a good rise in size performance, and exhibits excellent size performance effects. [Examples] Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited to these Examples. Example 1 <Preparation of sizing agent dispersion> Various ketene dimers and ester compounds shown in Table 1 were melted and mixed at 70 to 80°C, and warm water (70 to 80°C) containing various dispersants shown in Table 2 was mixed. was added, emulsified at a pressure of 200 kg/cm ² using a high-pressure discharge homogenizer, and further cooled to obtain a sizing agent composition. The composition of the obtained sizing agent composition and the dispersant used are shown in Tables 1 and 2.

【table】

【table】

【table】

【table】

[Table] <Paper making conditions> The paper used in this test was manufactured under the following conditions. Pulp: LBKP (Canadian Standard Freeness 400ml) Sizing agent: Solid content 0.1% based on pulp weight Fixing agent: Cationized starch (commercial product), solid content 0.2-0.8% based on pulp weight Retention aid: Cationic polyacrylamide Polymer (commercially available), solid content 0.02% based on pulp weight Filler: Heavy calcium carbonate (commercially available), adjusted so that the calcium carbonate in the paper is 12% PH at fixing: 8.2 Order of addition: Pulp - Filler - Fixing agent - Sizing agent -
Retention improver Paper making: Tatsupi square hand paper machine Press: 3.5 kgw/cm ² × 2 minutes Drying: Rotary dryer, 100℃/40 seconds Tsubo amount: 70 g/m ² <Size degree test> Size degree The test was conducted in the following manner. Sizing test: Stekicht method (JIS P-8122)
Fold the four sides of the test paper upward to form a boat shape and float it on a 2% NH ₄ SCN aqueous solution.
At the same time as floating, a drop of a 1% FeCl ₃ aqueous solution was dropped onto the test paper from above, and the time (seconds) until both aqueous solutions penetrated the paper and came into contact with it, and three red spots of iron thiocyanate appeared, was measured. Table 3 shows the test results of measuring the sizing of paper made under the above conditions immediately after paper making and after one day of humidity control (20° C. x 60%). The size degree immediately after papermaking indicates the quality of the rise of the size effect, and the higher the value, the better. <Stability test of sizing composition> The dispersion stability test of the sizing composition was carried out using the sizing composition shown in Table 1 after being left at temperatures of 5°C, 20°C, and 40°C for 4 weeks. The dispersion state of the agent was visually observed. The results are shown in Table 3. The meanings of the symbols shown in Table 3 are as follows. ○: The emulsified state is almost the same as the initial state. Δ: The emulsion has slightly thickened, but can be used. ×: The emulsion was significantly thickened or gelatinized and could not be used. Or it is unusable due to creaming.

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Claims (1)

[Claims] 1 General formula (1) (In the formula, R ₁ and R ₂ are alkyl groups having 8 to 24 carbon atoms,
It is an alkenyl group or an aryl group. ) and the ketene dimer represented by the general formula (2) (In the formula, R ₃ is an alkyl group or alkenyl group having 1 to 20 carbon atoms, AO is an alkylene oxide having 2 to 4 carbon atoms, l is 0 to 5, m is 0 to 200, n
is an integer from 1 to 4. ) A sizing agent composition for paper manufacturing, characterized in that it consists of an aqueous dispersion in which a mixture of the following ester compounds is dispersed in water in a weight ratio of 99.8/0.2 to 80/20.