JPS6225798B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a sizing agent for paper manufacturing. For more information,
The present invention relates to a reactive paper-making sizing agent mainly comprising an aqueous emulsion of an α-olefin-maleic anhydride copolymer. Generally known sizing agents used in the paper industry include acidic sizing agents (rosin sizing agents), cationic sizing agents (neutral sizing agents), and reactive sizing agents. These sizing agents are added to the pulp slurry along with an appropriate amount of filler during the papermaking process, and impart appropriate hydrophobicity to the paper. Clay, talc, etc. are known as fillers, but in recent years it has been proposed to use calcium carbonate, which is inexpensive and of high quality. Acidic sizing agents have excellent sizing effects and are currently most commonly used, but since papermaking is carried out in an acidic region, calcium carbonate cannot be used as a filler. Cationic sizing agents can be used for paper making in the neutral range, so calcium carbonate can be used as a filler, but they are more expensive than the acidic sizing agents mentioned above, and their sizing effects are still unsatisfactory. It's not a state. As reactive sizing agents, alkyl ketene dimers or alkenyl succinic anhydride emulsions are known, which react directly with the valve to provide excellent sizing effects. These sizing agents also allow paper making in the neutral range, and calcium carbonate can be used as a filler, but the size effect of alkyl ketene dimer emulsion is extremely insufficient immediately after paper making, so it is difficult to express the size effect. It takes at least 2 to 3 days, and alkenylsuccinic anhydride is hydrolyzed after emulsion and its reactivity with pulp gradually decreases, so it must be used within a short period of time after emulsion. There are problems such as not being able to do so. Therefore, the present inventors did not have these problems, and
In order to obtain a sizing agent for paper manufacturing that can provide excellent sizing effects, the present invention was arrived at as a result of studies. That is, the gist of the present invention is that α having 20 to 60 carbon atoms
- An average molecular weight of 2000 to 2000 obtained by copolymerizing olefin and maleic anhydride at a molar ratio of maleic anhydride/α-olefin of 1 to 2.
30,000, a paper-making sizing agent mainly consisting of an aqueous emulsion of α-olefin-maleic anhydride copolymer. Next, the present invention will be explained in detail. The α-olefin-maleic anhydride copolymer, which is the main component of the paper sizing agent of the present invention, has a carbon number of 20 to
It is obtained by copolymerizing α-olefin No. 60 and maleic anhydride at a molar ratio of maleic anhydride/α-olefin in the range of 1 to 2, and the average molecular weight is in the range of 2,000 to 30,000. . If the carbon number of the α-olefin reacted with maleic anhydride is too long or too short, the sizing effect of the resulting sizing agent will be reduced. Therefore, the α-olefin has 20 to 60 carbon atoms, preferably 35 to 50 carbon atoms. The α-olefin used is preferably linear, but may be branched. Further, as long as the α-olefin has a carbon number within the above range, a mixture of α-olefins having various carbon numbers may be used. If the molar ratio of maleic anhydride/α-olefin when reacting α-olefin and maleic anhydride is large, the amount of the performance stabilizer as a sizing agent increases, but the melt viscosity increases, making emulsification difficult. Moreover, if the molar ratio is small, emulsification is easy, but the performance stability as a sizing agent is reduced. Therefore, the maleic anhydride/α-olefin molar ratio is between 1 and 2, preferably between 1.2 and 1.4. If the average molecular weight of the α-olefin-maleic anhydride copolymer is too large, a good aqueous emulsion cannot be obtained, and if it is too small, sufficient size effect and performance stability cannot be obtained.
It is in the range of 2000-30000, preferably 5000-10000. The copolymerization reaction of α-olefin and maleic anhydride is carried out in the presence of a radical catalyst by a solution polymerization method or a solvent-free (bulk) polymerization method according to a conventional method. In the solution polymerization method, xylene,
Toluene, benzene, etc. are used, and suitable polymerization conditions are 60 to 140°C for 3 to 8 hours. After the polymerization reaction is completed, the desired copolymer can be easily obtained by separating the solvent from the reaction mixture by distillation. The degree of polymerization is adjusted by appropriately changing the type and amount of solvent. On the other hand, in order to increase productivity, copolymerization without a solvent is advantageous, but it is necessary to appropriately adjust the degree of polymerization by using an appropriate radical transfer agent or increasing the polymerization temperature. . As the radical transfer agent, lauryl mercaptan, stearyl mercaptan, p-tert-butylphenol, etc. are effective, and it is appropriate to add them in an amount of 1/100 to 1/10 mole based on maleic anhydride. Furthermore, by simply raising the polymerization temperature to 160 to 200°C, a copolymer having an appropriate degree of polymerization can be obtained without using these radical transfer agents. In this case, an effective method for obtaining a copolymer with a good hue is to carry out polymerization while continuously supplying maleic anhydride into the α-olefin during the copolymerization reaction. The copolymer thus obtained is emulsified in an aqueous medium to form a paper sizing agent. To emulsify the copolymer in an aqueous medium, the above copolymer, a surfactant in an amount of 0.01 to 0.4 times the weight of the copolymer, and water in an amount of 1 to 10 times the total weight of these are mixed. Mixing and emulsification may be carried out at 50 to 120°C, preferably 80 to 100°C. As the surfactant, for example, a nonionic surfactant such as polyoxyalkylene alkyl ether or polyoxyalkylene aryl ether, or an anionic surfactant such as higher fatty acid or alkylbenzenesulfonic acid is used. The average particle diameter of the emulsion is preferably adjusted to a range of 0.2 to 2.0μ in consideration of size properties and stability of the sizing agent. The average particle diameter of the emulsion is adjusted by appropriately selecting the amount of surfactant used or stirring conditions. The α-olefin-maleic anhydride copolymer in the paper sizing agent of the present invention imparts a high sizing effect by chemically bonding the acid anhydride group contained in the molecule with the hydroxyl group of cellulose fibers. can do. Furthermore, since the above-mentioned copolymer contains a large number of acid anhydride groups in one molecule, it has high performance stability as a sizing agent and has excellent adsorption or adhesion to cellulose fibers. To use the sizing agent of the present invention for internal sizing, add it to a slurry of moderately beaten pulp (freeness about 100 to 400 c.c.) at a concentration of 0.5 to 3% by weight.
The sizing agent of the present invention is added in an amount of 0.2 to 3.0 relative to the pulp weight.
% by weight is added under stirring, and then 0.2 to 6.0% by weight of a cationic fixing agent based on the weight of the pulp is added under stirring and fixed. In addition, as the cationic fixing agent, cationized starch, polyamino resin,
Polyethyleneimine or polyamide epichlorohydrin resin can be used. The pulp slurry thus treated is made into paper according to a conventional method. Since the sizing agent of the present invention allows paper making in a neutral range, generally available light or heavy calcium carbonate can be used as a filler during paper making. Incidentally, the sizing agent of the present invention can also be used for surface sizing together with starch or polyvinyl alcohol. As described above in detail, the paper sizing agent of the present invention has high reactivity with cellulose fibers and excellent performance stability. EXAMPLES Next, the present invention will be specifically explained using examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. Example 1 (i) Production of α-olefin-maleic anhydride copolymer α-olefin having 30 to 60 carbon atoms, dialne
30+ (registered trademark of Mitsubishi Chemical Industries, Ltd., average carbon number 48), 600 g of maleic anhydride, and 600 g of xylene were placed in a flask, heated to 110°C under a nitrogen atmosphere, and then heated to 110°C with stirring.
- 1/4 of 11.4 g of butyl peroctoate,
The mixture was added at 1 hour intervals, and the reaction was allowed to proceed for an additional 3 hours after the addition. After the reaction is complete, xylene is distilled off from the reaction mixture to obtain the α-olefin-maleic anhydride copolymer.
Obtained 685g. The hue of the obtained copolymer was GN2-3, and the melting point was 72.
It is a wax-like solid with a melting temperature of 100 °C.
It was 139C.P. Further, its number average molecular weight was determined to be 8350 by GPC method. (ii) Production of aqueous emulsion 30 g of the above α-olefin-maleic anhydride copolymer and 12 g of emulsifier Ribonox NCK/M (trademark of Lion Oil Co., Ltd., ethylene oxide adduct of nonylphenol, HLB = 14.1)
Pour into a 300c.c. tall beaker and place on a water bath.
It was heated and melted at 85-90°C. Next, 158 g of water at 85 to 90°C was gradually added to this while stirring to effect layer inversion emulsification, and then cooled to room temperature under water cooling to obtain a homogeneous aqueous emulsion with a bluish opalescent color. . (iii) Sizing The above aqueous emulsion was added to a pulp slurry with a concentration of 1% by weight (NBKP50% by weight, LBKP50% by weight, Freeness 405c.c.) at the addition rate shown in Table 1, and then the aqueous emulsion A fixing agent CATO-2 (trademark of Oji Nacional Co., Ltd., cationized starch) was added in an amount twice the weight of the emulsion. After the addition, a square sheet (25cm x 25cm) was made using a table paper machine, and dried at 110℃ for 3 minutes with a rotary dryer to give a basis weight of 60.
~62 g/ ^m2 paper was produced. Table 1 shows the results of measuring the sizing of the obtained paper. Regarding sizing, according to JIS P8122 "Stekicht sizing test method for paper", the above sizing agent-treated paper was floated on a 2% ammonium thiocyanate solution at 20°C, and at the same temperature
The time from when one drop of a solution of ferric chloride (% by weight) was dropped with a pipette to the appearance of three red spots was measured using a seconds clock, and the number of seconds was displayed. For comparison, paper was made in the same manner using a commercially available petroleum resin-based cationic sizing agent and an alkenylsuccinic anhydride-based reactive sizing agent, and the sizing degree of the resulting paper was measured in the same manner. These results are also shown in Table 1 as Comparative Example 1 and Comparative Example 2, respectively.

【table】

[Table] Fixing agent: Cationized starch

Claims (1)

[Scope of Claims] 1. An average molecular weight of 2000 to 2000 obtained by copolymerizing α-olefin having 20 to 60 carbon atoms and maleic anhydride at a maleic anhydride/α-olefin molar ratio of 1 to 2. A paper-making sizing agent based on an aqueous emulsion of 30,000 α-olefin-maleic anhydride copolymer. 2. The sizing agent according to claim 1, wherein the aqueous emulsion contains an α-olefin-maleic anhydride copolymer, a surfactant in an amount of 0.01 to 0.4 times the weight of the copolymer, and 1 for total weight
A paper sizing agent obtained by mixing and emulsifying ~10 times the weight of water at 50 to 120°C.