JPH039236B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a neutral papermaking process using a substituted succinic anhydride type sizing agent. More specifically, after passing through a water-in-oil emulsion consisting of substituted succinic anhydride, a surfactant, and water, it is diluted with water and phase inverted to obtain a finely dispersed oil-in-water emulsion. The present invention relates to a neutral paper making method. Sizing agents for paper manufacturing have conventionally been widely used, such as sizing agents produced from natural rosin or modified rosin, particularly so-called reinforced rosin sizing agents obtained by saponifying maleic acid adducts of rosin.
These sizing agents are employed in acid sizing methods in which the sizing is fixed by sulfuric acid. However, the use of sulfuric acid, an essential ingredient, lowers the pH of the papermaking system, which can lead to corrosion of papermaking equipment.
The disadvantage is that the strength and durability of the resulting paper is reduced. Furthermore, because it is difficult to use an inexpensive alkaline filler such as calcium carbonate, it is difficult to expect a significant reduction in paper production costs. In order to solve the drawbacks of the acidic sizing method, research has been conducted on neutral papermaking methods that do not use sulfate, and so-called neutral sizing agents have been proposed that provide excellent sizing effects to paper under papermaking conditions in the neutral range. has been done.
For example, the sizing agent containing cyclic dicarboxylic acid anhydride described in Japanese Patent Publication No. 39-2305;
-Sizing agent consisting of maleic anhydride adduct of internal olefin described in Japanese Patent Publication No. 28526, 1973-
Examples include a sizing agent comprising a substituted dicarboxylic acid anhydride, a polyoxyalkylene compound, and water, which is described in Japanese Patent No. 36044. By the way, in the paper manufacturing industry, the paper making process is required to be a continuous process from the viewpoint of production efficiency. All of the above neutral sizing agents are used in the form of emulsion, but because the anhydride ring of the substituted succinic anhydride, which is the active ingredient of the sizing agent, does not have sufficient hydrolytic stability, it is easily hydrolyzed and the original size is The disadvantage is that the size effect cannot be expressed. Therefore, it is necessary to disperse the sizing agent immediately before papermaking, or to provide a dispersion step during the papermaking process. Whichever method is adopted, the sizing emulsion must be added in a fixed amount to the pulp slurry without reducing the production efficiency of the papermaking process. Therefore, there is a current demand in the industry for the development of a continuous dispersion process in the above-mentioned neutral paper making method. Furthermore, there is a tendency to reduce the amount of sizing agent added from the viewpoint of resource saving and economic efficiency, and still expect a certain sizing effect. When using a substituted succinic anhydride emulsion sizing agent, there is a correlation between the particle size of the emulsion and the size effect (the smaller the particle size, the better the size effect). Therefore, it is expected that the above object can be achieved by obtaining an emulsion with a small particle size. However, Special Publication No. 39-2305 and Special Publication No.
All of the sizing agents described in Japanese Patent Publication No. 53-28526 have many restrictions in order to disperse the dicarboxylic acid anhydride in water, as is clear from the description in Japanese Patent Publication No. 53-36044. In other words, protective colloids, which are suspending agents such as cationized starch, gelatin, and polyvinyl alcohol, must be included as essential ingredients, and in addition, high-speed shakers,
Dispersion in water can only be achieved by using a specific strong stirring device such as a mechanical homogenizer or an ultrasonic homogenizer.
When using these strong stirring devices, usually
The dicarboxylic acid anhydride can be finely dispersed in water by the high shear force associated with high-speed stirring of about 10,000 to 20,000 rpm, and the size effect can be almost satisfied. However, since using this device requires a certain amount of residence time (more than 5 minutes), it is restricted to the so-called batch method, making it difficult to apply to actual machines that require a continuous papermaking process. Since it is a batch method, it has the disadvantage that the distributed processing efficiency per unit time is also poor. On the other hand, Japanese Patent Publication No. 53-36044 describes that by using a polyoxyalkylene compound as a surfactant in the substituted dicarboxylic anhydride, the suspension step using the strong stirring device can be omitted. ing. That is, when the dicarboxylic acid anhydride is suspended using the surfactant described in the same publication, such as polyoxyalkylene alkyl ether or polyoxyalkylene alkylaryl ether, the mixed pulp can be prepared without high-speed stirring. It is said that it is sufficient to simply pass it through an aspirator or orifice (hereinafter referred to as an orifice). When using such an orifice, it is suitable for continuous operation, unlike when using the above-mentioned strong stirring device, but if the pore size is small (for example, about 100 μm), sizing agents or accidentally mixed in The pores are likely to become clogged due to contaminants, resulting in a situation where continuous operation must be stopped. On the other hand, if the pore size is relatively large (for example, about 1000 μm), the clogging problem can be solved, but it tends to be difficult to form a fine dispersion of the substituted dicarboxylic anhydride, which is difficult to achieve in the actual paper-making process. It is still not satisfactory when applied to A specific example of the orifice is a ventilate type dispersion device, but it is difficult to adjust the feed amount and feed pressure of the sizing agent, and it is still unsatisfactory for continuous processing. Fine dispersion is also not sufficient. Especially in the case of one pass (one pass), it is difficult to say that it is sufficient. As mentioned above, conventionally known suspension (dispersion) methods for substituted succinic anhydride-type sizing agents are effective in obtaining fine dispersions that exhibit excellent sizing effects and in application to continuous papermaking processes. However, it is not possible to simultaneously satisfy the two required performances of providing a continuous dispersion process that is efficient, and there is much room for improvement. In view of the shortcomings of the prior art, the present inventors investigated various stirring devices and dispersion methods, and
As a result of intensive research to develop a continuous dispersion process that can obtain a finely dispersed sizing agent of substituted succinic anhydride, the three components consisting of substituted succinic anhydride, surfactant, and water were prepared all at once. It was surprisingly discovered that the above drawbacks can be overcome for the first time by forming a water-in-oil emulsion, followed by dilution with water, phase inversion, and obtaining an oil-in-water emulsion, and the present invention has been made based on the present invention. I was able to complete it. That is, the present invention provides a neutral papermaking method using a substituted succinic anhydride type sizing agent, in which the number of added moles of substituted succinic anhydride and ethylene oxide is 2 to 50.
Moles of polyoxyethylene type surfactant and water are charged all at once to form a water-in-oil emulsion with a solid content concentration of 60 to 95% by weight, and then the water-in-oil emulsion is mixed with water. The present invention relates to a neutral papermaking method characterized by providing a continuous dispersion step in which an oil-in-water type finely dispersed emulsion is obtained by dilution and phase inversion. The substituted succinic anhydride contained in the sizing agent in the present invention is not particularly limited,
Any conventionally known method can be used;
Examples include those described in Japanese Patent Publication No. 53-28526 and the like. More specifically (In the formula, R ¹ has 9 to 23 carbon atoms, preferably 13 to 23 carbon atoms.
19 alkyl or alkenyl group) and (or) a linear or branched substituted succinic anhydride represented by the general formula (): (In the formula, R ² represents a straight chain or branched alkyl group having 1 to 27 carbon atoms, R ³ represents a straight chain or branched alkyl group or alkenyl group having 2 to 28 carbon atoms, and R ² and the total number of carbon atoms in R ³ is 9 to 29,
Examples include branched substituted succinic anhydrides represented by (preferably 13 to 23). The substituted succinic anhydride represented by the above general formula () can be obtained by the addition reaction of α-olefin having a double bond at the terminal or an oligomer thereof and maleic anhydride. Specific examples of the substituted succinic anhydride include isooctadecenylsuccinic anhydride, n-hexadecenylsuccinic anhydride, dodecenylsuccinic anhydride, triisobutenylsuccinic anhydride, and these impurities. Examples include corresponding saturated substituted succinic anhydrides obtained by hydrogenating saturated substituted succinic anhydrides. The branched substituted succinic anhydride represented by the general formula () can be obtained by an addition reaction between an internal olefin and maleic anhydride. Specific examples of the substituted succinic anhydride include decene-5, dodecene-6, tetradecene-7, hexadecene-7, octadecene-9, and eicosene-11.
and the like, and the corresponding saturated substituted succinic anhydrides obtained by hydrogenating these unsaturated substituted succinic anhydrides. The reaction of the α-olefin or internal olefin with maleic anhydride is carried out in the presence or absence of a catalyst, preferably under an inert atmosphere, under normal pressure or increased pressure. Reaction temperature is 180~250℃,
The temperature is preferably 190 to 220°C, and the reaction time is 1 to 50 hours, preferably 10 to 36 hours. The molar ratio of olefins to maleic anhydride is not particularly limited, but is usually 0.4 to 2 moles of maleic anhydride per mole of olefins, preferably 0.4 to 2 moles of maleic anhydride.
A suitable amount is 0.8 to 1.3 mol. After the reaction is completed, substituted succinic anhydride can be obtained by removing unreacted olefins and maleic anhydride by distillation. In the present invention, a polyoxyethylene type surfactant having an added mole of ethylene oxide of 2 to 50 moles is an essential component for obtaining a fine dispersion of substituted succinic anhydride. There are no particular limitations on the surfactant that can be used in the present invention, and any conventionally known surfactants can be used alone or in combination. For example, examples of anionic surfactants include sodium dodecylbenzenesulfonate, sodium lauryl sulfate, ammonium salts of polyoxyethylene alkyl ether sulfate, and the former two are used in combination with the following nonionic surfactants:
Moreover, the latter may be used alone. Examples of nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl amine, polyoxyethylene alkyl amide, and polyoxyethylene alkyl ester. Examples include esters of alcohol and fatty acids, higher alcohols, and acetylated products of polyoxyethylene alkyl ether, acetylated products of polyoxyethylene alkyl phenyl ether, and acetylated products of polyoxyethylene sorbitan fatty acid ester. The present invention can suitably obtain a fine dispersion of substituted succinic anhydride, and can also provide a continuous dispersion process that can be applied to actual equipment.Furthermore, it is possible to use a specific stirring device as in the prior art. The purpose of the present invention can be achieved by using a conventional stirring device as it is without being subject to any restrictions. In the present invention, first, the three components of substituted succinic anhydride, surfactant, and water are mixed to form a water-in-oil emulsion. Here, water-in-oil emulsion refers to a case where the continuous phase is oil (substituted succinic anhydride and surfactant) and the dispersed phase is water. In the process of forming a water-in-oil emulsion, the mixing ratio of substituted succinic acid and surfactant is determined appropriately taking into account the foamability and particle size of the resulting fine dispersion, but it is usually determined by the weight ratio.
It is best to set the ratio to 100:5 to 100:20. If the amount of the surfactant used is less than this range, the particle size of the resulting dispersion becomes large, making it impossible to obtain the desired size effect, and if it exceeds this range,
This is not preferable because the resulting fine dispersion becomes foamy. On the other hand, the mixing ratio of the above two components and water should be carefully determined as it has a significant influence on the formation of water-in-oil emulsion, and the solid content concentration [substituted succinic anhydride in water-in-oil emulsion] should be carefully determined. They may be mixed so that the solid content concentration (weight %, hereinafter simply referred to as %) of the surfactant and the surfactant is 60 to 95%. When the concentration is less than 60%, an oil-in-water emulsion is directly obtained, with coarse particles having a particle diameter of usually 5 to 6 μm. On the other hand, if the concentration exceeds 95%, it is difficult to obtain an emulsion of fine particle size according to the present invention, and coarse particles usually have a particle size of 5 to 6 μm. Further, there are no restrictions on the stirring device used at this time, and general stirring devices such as a low-shearing force stirrer or a pipeline mixer can be used. Next, a predetermined amount of dilution water is added to the water-in-oil emulsion thus obtained, and an oil-in-water microdisperse emulsion of a predetermined concentration can be obtained through an inversion process. The device can be used as is. That is, in both the step of forming a water-in-oil emulsion and the step of inverting it to form an oil-in-water emulsion, for example, if each component is injected in a proportional injection method using a pipeline mixer, the papermaking process can be carried out. A compatible continuous dispersion process can be provided. The obtained emulsion has excellent storage stability and water dilution stability, and is a fine dispersion with an average particle diameter of usually 1 μm or less, so it can exhibit excellent size effects. The fine dispersion of the sizing agent obtained as described above is usually added to the pulp in an amount of 0.05 to 5% in terms of solid content. Furthermore, various cationic compounds such as polyethyleneimine resins, cationic polyacrylamide resins, cationic polyamide polyamine resins, cationic starch derivatives, etc. can be used to further improve the fixability of the sizing agent to the pulp. As described above, according to the present invention, a continuous dispersion process can be provided by forming a water-in-oil emulsion, adding diluting water and performing an inversion process to obtain an oil-in-water emulsion. This makes it possible to produce excellent neutral paper. Next, the method of the present invention will be explained in more detail with reference to Reference Examples, Examples, and Comparative Examples, but the present invention is not limited to these. Reference Example 1 An alkenylsuccinic anhydride was obtained by subjecting a branched α-olefin oligomer having 14 carbon atoms to an addition reaction with maleic anhydride. Reference Example 2 An alkenylsuccinic anhydride was obtained by subjecting a branched α-olefin oligomer having 20 carbon atoms to an addition reaction with maleic anhydride. Reference Example 3 Alkenylsuccinic anhydride was obtained by addition reaction of maleic anhydride to tetradecene-7. Reference Example 4 Alkenylsuccinic anhydride was obtained by addition reaction of maleic anhydride to eicosene-11. Reference Example 5 Alkenylsuccinic anhydride was obtained by subjecting octadecene-9 to an addition reaction with maleic anhydride. Example 1 5 parts of polyoxyethylene nonyl phenyl ether (the number of moles of ethylene oxide added is 18) and 25 parts of deionized water were each added to 50 parts (by weight, the same applies hereinafter) of the alkenylsuccinic anhydride obtained in Reference Example 1. Proportionally injected, these were passed through a pipeline mixer once to form a water-in-oil emulsion with a solids concentration of 68.8%, and 5420 parts of deionized water was added to this, diluted and stirred, and phase inverted to increase the solids concentration. 1%
An oil-in-water emulsion of 100% was obtained continuously. The average particle diameter and standard deviation of the emulsion were measured using a Coulter counter (MODEL TA-type, Coulter Electronics).
ELECTRONICS)).
The values were 0.835μm and 0.713μm, respectively. The size effect of the emulsion was also measured according to the size performance test method described below. The results are shown in Table 1. (Size Performance Test) Pulp (L-BKP) was beaten to 450 ml of Canadian Standard Freeness to form a 1% aqueous slurry. A polyamide polyamine resin (Arafix 100, manufactured by Arakawa Chemical Industry Co., Ltd.) was added to the slurry as a fixing agent at 0.3% (solid content equivalent) based on the pulp, and the sizing agent obtained in this example was added to the pulp. 0.1 or 0.2% (solid content equivalent)
In addition, it was evenly dispersed. The resulting slurry was made into paper using a Tatsupi Standard Sheet Machine to have a basis weight of 60±1 g/m ² . The resulting wet paper is then compressed and dehydrated.
After drying at 100°C for 1 minute, the humidity was controlled at a relative humidity of 65% for 24 hours, and then the degree of size (seconds) of each was measured by the Stekicht method. Examples 2-5 Various oil-in-water emulsions were obtained in the same manner as in Example 1, except that the various alkenylsuccinic anhydrides obtained in Reference Examples 2-5 were used. These average particle diameters, standard deviations, and size effects were measured in the same manner as in Example 1. The results are shown in Table 1. Examples 6 to 10 Various oil-in-water emulsions were prepared in the same manner as in Example 1, except that the type of alkenylsuccinic anhydride or surfactant used in Example 1 was changed as shown in Table 2. These average particle diameters, standard deviations, and size effects were measured in the same manner as in Example 1. The results are shown in Table 2. Examples 11-12 In Example 1, the solid content concentration of the water-in-oil emulsion was 80% and 90% (Examples 11 and 12, respectively).
Oil-in-water emulsions were obtained in the same manner as in Example 1, except that the water content was adjusted so that the amount of water was 10%. These average particle diameters, standard deviations, and size effects were measured in the same manner as in Example 1. The results are shown in Table 2. Comparative Examples 1 to 3 In Examples 1 to 3, alkenylsuccinic anhydride, surfactant, and water were directly passed through a pipeline mixer once to a solid content concentration of 1% without passing through a water-in-oil emulsion. Various oil-in-water emulsions were obtained. These average particle diameters, standard deviations, and size effects are shown in Example 1.
It was measured in the same manner. The results are shown in Table 2. Comparative Example 4 5 parts of the alkenylsuccinic anhydride obtained in Reference Example 1 and 0.5 part of the same polyoxyethylene nonyl phenyl ether used in Example 1 were added to 100 parts of an aqueous medium containing 3 parts of acrylamide polymer. After adding and mixing the mixture, this was prepared in Example 1.
An oil-in-water emulsion was formed with one pass through a pipeline mixer in the same manner as above. The emulsion properties and size effects of the obtained oil-in-water emulsion were investigated in the same manner as in Example 1. The results are shown in Table 3. Comparative Example 5 3 parts of acrylamide polymer and Example 1
To 100 parts of an aqueous medium containing 0.5 parts of the same polyoxyethylene nonyl phenyl ether used in
Alkenylsuccinic anhydride 5 obtained in Reference Example 1
After addition and mixing, it was passed once through a pipeline mixer as in Example 1 to form an oil-in-water emulsion. The emulsion properties and size effects of the obtained oil-in-water emulsion were investigated in the same manner as in Example 1. The results are shown in Table 3. Comparative Example 6 A mixture of 5 parts of the alkenylsuccinic anhydride obtained in Reference Example 1 and 0.5 part of the same polyoxyethylene nonyl phenyl ether used in Example 1 was added to water.
After dispersing in 90 parts of the dispersion, an aqueous medium 13 containing 3 parts of acrylamide polymer was added to the resulting dispersion and mixed, and the mixture was passed once through a pipeline mixer in the same manner as in Example 1. An oil-in-water emulsion was formed. The emulsion properties and size effects of the obtained oil-in-water emulsion were investigated in the same manner as in Example 11. The results are shown in Table 3. Comparative Example 7 5445 parts of deionized water was gradually added to a mixture of 50 parts of the alkenylsuccinic anhydride obtained in Reference Example 1 and 5 parts of polyoxyethylene nonyl phenyl ether (the number of moles of ethylene oxide added was 18). It was added dropwise and stirred to obtain an oil-in-water emulsion with a solid content concentration of 1%. Example 1 shows the emulsion properties and size effects of the obtained oil-in-water emulsion.
I investigated in the same way. The results are shown in Table 3.

【table】

【table】

【table】

【table】

Claims (1)

[Scope of Claims] 1. In a neutral papermaking method using a substituted succinic anhydride type sizing agent, substituted succinic anhydride, a polyoxyethylene type surfactant with an added mole of 2 to 50 moles of ethylene oxide, and water are added. After charging all at once to form a water-in-oil emulsion with a solid content concentration of 60 to 95% by weight, the water-in-oil emulsion is diluted with water and phase inverted to form an oil-in-water emulsion. A neutral papermaking method characterized by providing a continuous dispersion step to obtain a finely dispersed emulsion. 2 The average particle size of the oil-in-water finely dispersed emulsion is
The method according to claim 1, wherein the particle size is 1 μm or less.