JPH0474479B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for sizing paper, more particularly comprising the use of a highly reinforced specific rosin-based emulsion as a sizing agent.
The present invention relates to a method for sizing various types of base paper, such as gypsum board base paper, fusuma base paper, cup base paper, etc., which particularly require hot water sizing. When making these various base papers, addition reaction products (hereinafter referred to as adducts) are obtained by reacting rosin with a dibasic acid, particularly fumaric acid or maleic acid, in a range of 10 to 20% by weight. ) It is recommended to use a high-strength solution-type rosin-based sizing agent that has been completely saponified with an alkali, as disclosed in JP-A-56-91099 or JP-A-55.
-84499, and such a sizing agent has been used conventionally. However, the hydrothermal sizing effect obtained using this type of solution-type rosin-based sizing agent is still not sufficient, and as a result, it is necessary to add an excessive amount of sizing agent. However, it is not satisfactory in terms of economic efficiency and problems such as foaming trouble and pitch trouble during the paper making process. In contrast, 10% of maleic or fumaric acid
Emulsion-type rosin-based sizing agents using adducts obtained by using less than % by weight have been widely used because they have the following advantages over the solution-type rosin-based sizing agents mentioned above. There is. (1) significantly less foaming in papermaking systems, (2) ability to reduce the amount of aluminum sulfate used, (3) usability over a wide pH range from acidic to neutral, and (4) size. The effect is extremely good, and the addition rate of the sizing agent can be significantly reduced. However, these conventional emulsion-type rosin-based sizing agents have the disadvantage of being inferior in hydrothermal sizing compared to highly reinforced solution-type rosin-based sizing agents, so the above-mentioned requirements for hydrothermal sizing are The current situation is that there is almost no use for paper making of the various base papers used. However, as a result of intensive studies by the present inventors to improve the hydrothermal sizing effect of such conventional emulsion-based sizing agents, we found that the content of acidic compounds, which are diacid base acids, is as high as 10 to 20% by weight. When using a strong rosin emulsion type sizing agent, an excellent hydrothermal sizing effect that cannot be obtained with the highly strengthened solution type rosin sizing agent described above can be obtained, and moreover, it is possible to obtain an excellent hydrothermal sizing effect that cannot be obtained with the highly strengthened solution type rosin type sizing agent described above. The present invention was completed based on the discovery that it is possible to obtain a device that fully combines the advantages of the above. That is, the present invention adds a sizing agent, aluminum sulfate, and optionally a retention aid mainly composed of ionic polyacrylamide to a pulp slurry, thereby sizing base paper that requires hydrothermal sizing. When carrying out the procedure, apply the formula to the rosin. An addition reaction product (reinforced rosin) obtained by reacting 10 to 20% by weight of an acidic compound having a bond represented by The present invention provides a sizing method in which an anionic emulsifier such as oxyethylene alkyl ether sulfate, polyoxyethylene alkyl phenyl ether sulfosuccinate, or polyoxyethylene alkyl ether sulfosuccinate is dispersed in water. The method of the present invention will be explained in detail below. First, the aqueous emulsion described above is prepared by adding fumaric acid to molten rosin in an amount of 10 to 20% based on its weight and reacting at 200°C for 5 hours. conduct,
Then 1 to 10% by weight, preferably 2 to 10% by weight of the molten adduct, which is the addition reaction product thus obtained, is added to the molten adduct.
5% by weight of an aqueous emulsifying dispersant and a predetermined amount of hot water are added and stirred to prepare a so-called W/O emulsion in which the agct is a continuous phase and water is a dispersed phase. It is obtained by adding water and stirring to turn it into a so-called O/W emulsion, in which water is a continuous phase and adducts are a dispersed phase. As a high strength rosin emulsion type sizing agent, it is particularly suitable for use as a hydrothermal sizing agent in the present invention. Here, typical rosins used to obtain the above adduct include:
Examples include rosin, gum rosin, tall oil rosin, and mixtures thereof, but it goes without saying that any type of commercially available rosin can be used. Among these, gum rosin is particularly suitable from the viewpoint of hydrothermal size effect. On the other hand, typical acidic compounds used to obtain the adduct include fumaric acid, maleic acid, acrylic acid, itaconic acid, maleic anhydride, and the like.
Some contain specific bonds as shown in the formula, but fumaric acid or maleic acid is particularly suitable from the viewpoint of hydrothermal size effect. Further, as emulsifying and dispersing agents used to emulsify and disperse the adduct, polyoxyethylene alkyl phenol ether sulfate (polyoxyethylene alkyl phenyl ether sulfate),
Examples include polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl phenyl ether sulfosuccinates, polyoxyethylene alkyl ether sulfosuccinates, and these may be used alone or in combination of two or more. It is also permissible to use the above-mentioned emulsifying and dispersing agents in combination with various known and commonly used emulsifying and dispersing agents. In the method of the present invention, the high-strength rosin-based emulsion type sizing agent obtained as described above is used as a hydrothermal sizing agent, and further, for example, aluminum sulfate, or aluminum sulfate and ionic polyacrylamide are added. It is used as a distillation improver (fixing agent) to size pulp slurry by conventional methods. According to the method of the present invention, various pulps such as ground wood pulp used as pulp for gypsum board base paper or pulp for sliding door paper, bleached kraft pulp used for used newspapers, cardboard boxes, cupboards, etc. On the other hand, it can provide excellent hydrothermal sizing that could not be obtained with conventional sizing agents. Furthermore, according to the method of the present invention, compared to the conventional method using the above-mentioned high-strength rosin solution type sizing agent as a sizing agent, problems with foaming in the papermaking system can be significantly reduced, and the addition rate of aluminum sulfate can also be reduced. It provides various advantages such as providing stable sizing even if the paper pH changes due to fluctuations in pulp raw materials, and the ability to significantly reduce the addition rate of sizing agents due to the extremely excellent hydrothermal sizing effect. . Next, the present invention will be specifically explained with reference to Examples and Comparative Examples, and all references to "%" mean "% by weight" unless otherwise specified. Example 1 Put 850g of gum rosin into a round bottom flask equipped with a stirrer, thermometer and nitrogen inlet tube, melt it completely at 160°C, add 150g of fumaric acid with stirring, and melt it at 200°C. The addition reaction was allowed to proceed for 5 hours. The adduct produced here contains 15% fumaric acid based on the total addition reaction product, and has a softening point of 144° C. and an acid value of 281. Then, this adduct
^200g of nonylphenol polyethylene oxide sulfate ammonium salt (polyethylene oxy 100 g of hot water containing ethylene nonyl phenyl ether ammonium sulfate (additional moles of ethyleneoxy = 10 moles) was added and thoroughly stirred to obtain a W/O emulsion. Next, by adding 108g of hot water preheated to 120°C with vigorous stirring, the solid content was reduced to 50%.
% highly reinforced rosin emulsion type sizing agent was obtained. Hereinafter, this will be abbreviated as "sizing agent S-1." After that, a predetermined amount of sizing agent S-1 and aluminum sulfate were added to a 3% slurry of the predetermined pulp, and the sheet was made to a basis weight of 70±1 g/m ² using a Noble & Wood hand sheet machine. The paper was made into The obtained wet paper was compressed and dehydrated until the moisture content became 67%, and then dried at 110°C for 1 minute.
Then, the paper stock thus obtained was heated to 20°C and 65% RH.
After being left in a constant temperature and humidity environment for 24 hours, the size of the hot water was measured. Hot water size is measured by floating a 7cm x 7cm piece of paper on hot water at a specified temperature with the back side facing down, and measuring the time (in seconds) it takes for the hot water to penetrate into the front side of the paper. It is. The results are shown in Tables 1, 2, 3 and 4, respectively. Example 2 Except for changing the amount of fumaric acid used to 127g,
A sizing agent was obtained by addition reaction and emulsification in the same manner as in Example 1, and then the degree of hydrothermal sizing was measured. The results are shown in Tables 1, 2, 3 and 4, respectively. The sizing agent obtained in this example is abbreviated as "sizing agent S-2." Example 3 Except for changing the amount of fumaric acid used to 187g,
A sizing agent was obtained by addition reaction and emulsification in the same manner as in Example 1, and then the degree of hydrothermal sizing was measured. The results are shown in Table 1. The sizing agent obtained in this example is “Sizing agent S”.
-3". Examples 4 to 6 The same amount of the adduct obtained in Example 2 was used, and as an emulsifying dispersant, oleyl ether polyethylene oxide ammonium sulfate salt (polyoxyethylene oleyl ether ammonium sulfate salt) (number of moles of ethylene oxide added = 6 moles), nonyl Phenol polyethylene oxide sulfosuccinate sodium salt (polyoxyethylene nonyl phenyl ether sulfosuccinate sodium salt) (number of moles of ethylene oxide added = 10 moles) and dodecyl ether polyethylene oxide sulfosuccinate sodium salt (polyoxyethylene dodecyl ether sulfosuccinate sodium salt) ( Three types of sizing agents were obtained in the same manner as in Example 1, except that the number of moles of ethylene oxide added = 8 moles), and then the degree of hydrothermal sizing was measured. The results are shown in Table 1. The sizing agent obtained in this example was the one obtained in the example (Example 4) using oleyl ether polyethylene oxide ammonium sulfate salt (polyoxyethylene oleyl ether ammonium sulfate salt) and was designated as "Sizing agent S-4". ,
Nonylphenol polyethylene oxide sulfosuccinate sodium salt (polyoxyethylene nonyl phenyl ether sulfosuccinate sodium salt)
The product obtained in the example using polyoxyethylene dodecyl ether sulfosuccinate (Example 5) was designated as "Sizing Agent S-5", and the product obtained in the example using polyoxyethylene dodecyl ether sulfosuccinate sodium salt (Example The product obtained in step 6) is abbreviated as "Sizing agent S-6." Comparative example 1 9% fumarated rosin adduct obtained by addition reaction of 910 g of gum rosin and 90 g of fumaric acid by a conventional method. A sizing agent was obtained by emulsification in the same manner as in Example 1, except that the same amount of was used.
Hydrothermal sizing was then measured. The results are shown in Tables 1, 2, 3 and 4. The control sizing agent obtained in this example is abbreviated as "sizing agent S'-1." Comparative Example 2 Except that the same amount of a high-strength rosin solution-type sizing agent with a solid content of 50% obtained by completely saponifying the adduct obtained in Example 1 with an aqueous potassium hydroxide solution in a conventional manner was used. The hydrothermal sizing degree was measured in the same manner as in Example 1. The results are shown in Tables 1, 2, 3 and 4, respectively. The sizing agent obtained in this example was “Sizing agent S′-
It is abbreviated as "2". Tables 1 and 2 are evaluations of gypsum board base paper formulations, Table 3 is an evaluation of pulp for fusuma base paper, and Table 4 is an evaluation of pulp for cup base paper. Table 1 shows the case where only ammonium sulfate is used as the fixing agent for the sizing agent, and the pulp has a Canadian Standard Freeness (hereinafter abbreviated as CSF) of 165
ml of old newspaper was used. aluminum sulfate 2.0
% (relative to pulp solid content), and the papermaking pH was adjusted with sodium hydroxide. The addition rate of the sizing agent is as shown in the table. Table 2 shows the case where aluminum sulfate and ionic polyacrylamide are used as the fixing agent and retention agent for the sizing agent, and the pulp is a mixture of old newspaper and old cardboard at a ratio of 8:2 (weight ratio). A sizing agent was added at 0.5% (based on pulp solid content). The addition rate of the fixing agent, etc. (to pulp solid content ratio) is as described in the table. Third
In the table, deinked pulp (CSF = 182ml) was used as the pulp, aluminum sulfate was 2.0% (based on pulp solid content), anionic polyacrylamide was 0.2% (based on pulp solid content), and cationic polyacrylamide was used. When using 0.05% (same as above) (papermaking PH
4.5) is the evaluation result. The addition rate of the sizing agent is as shown in the table. Table 4 shows that a mixed pulp (csf = 350 ml) with L-BKP/N-BKP = 5/5 (weight ratio) was used as the pulp, and cationic polyacrylamide was added at 0.2% (solid content ratio of the pulp).
These are the evaluation results when 2.0% (same as above) of aluminum sulfate and aluminum sulfate were used together (papermaking pH 4.5). The addition rate of the sizing agent is as shown in the table. The "coffee penetration time" in this table is a guideline for the size of hot water.
The evaluation was done by floating a piece of paper with the back side facing down and measuring the time (minutes) it took for a 1cm sized "stain" to form on the surface of the paper.

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Claims (1)

[Claims] 1. A base paper requiring hydrothermal sizing is prepared by adding a sizing agent, aluminum sulfate, and optionally a retention aid mainly composed of ionic polyacrylamide to a pulp slurry. When sizing, use the formula for rosin as the above sizing agent. An addition reaction product obtained by reacting 10 to 20% by weight of an acidic compound having a bond shown in A method for sizing paper, which comprises using an aqueous emulsion dispersed in water with an anionic emulsifier such as ethylene alkyl ether sulfate, polyoxyethylene alkyl phenyl ether sulfosuccinate or polyoxyethylene alkyl ether sulfosuccinate.