JP2850124B2 - Paper manufacturing method - Google Patents

Description

The present invention relates to a method for producing paper sized using a sizing agent.

[Conventional technology]

Because paper is made of hydrophilic cellulose fiber,
It has the property of absorbing water and other fluids well. Therefore, when writing or printing with water-based ink or the like, it is essential to stop bleeding or stopping the ink, and sizing for this is required. As is well known, sizing suppresses the property of paper to absorb liquids, so-called sizing or water resistance, as well as water repellency and waterproofness. Rosin-based sizing agents have been frequently used as sizing agents for this sizing.However, recently, neutral paper has been brought up due to the problem of deterioration of acidic paper. Sizing agents are in the limelight.

[Problems to be solved by the invention]

However, in sizing, if a large amount of sizing agent is used in a large amount, paper and equipment will be stained.If the amount is too small, the sizing effect will not be sufficient. It is desired to develop a new usage method. In addition, in the case of a ketene dimer-based aqueous dispersion useful as a neutral sizing agent, the size level is generally still low immediately after passing through the dryer part after forming the paper web, and tends to increase over time. There is. Therefore, the workability in the paper making process is reduced, and problems in quality control tend to occur.

In addition, when a size press is performed during the papermaking process, the degree of sizing before the size press is insufficient, so that the amount of liquid absorbed by the size press solution increases, and therefore the strength of the wet paper after the size press is reduced. In addition to problems such as paper breakage and the like, there is a problem that drying in a dryer bar after size pressing is not successful.

In order to solve such a problem, attempts have been made to use a ketene dimer-based aqueous dispersion in combination with various kinds of cationic resins (for example, JP-A-48-48702, JP-A-55-137296). And JP-A-56-101998) have not yet obtained satisfactory results.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to solve the above problems and to establish a method for producing paper having an unprecedented sizing degree and excellent sizing effect.

[Means for solving the problem]

The present inventor has repeatedly studied to achieve the above object, and as a result, completely different from the conventional method of using various additives, paper after being pressed in a press part, especially after being dried in a dryer part. Was found to be able to achieve the object by a simple and economical method of exposing to a steam before the size press.

That is, the present invention provides a method for producing paper sized using a sizing agent, wherein the paper is exposed to steam at a place after being pressed by a press part and before a size press. It is intended to provide a manufacturing method.

 Hereinafter, the present invention will be described in detail.

The sizing agent used in the present invention is a ketene dimer compound, a substituted cyclic dicarboxylic anhydride, a rosin sizing agent,
It is one or more sizing agents selected from alkenyl succinates and the like, and a ketene dimer compound of the general formula (I) is particularly preferable.

The ketene dimer compound has the formula (I) (Wherein R ₁ and R ₂ represent a hydrocarbon group having 8 to 30 carbon atoms). A ketene dimer represented by the following formula: is a starch having a protective colloid function, particularly a cationized starch or a cationic or amphoteric vinyl copolymer. And used as an aqueous dispersion obtained by dispersing in an aqueous continuous phase in the presence of a surfactant as necessary. It should be noted that a cationic resin which promotes the size expression may be added to this.

Substituted cyclic dicarboxylic anhydride is JP-B-53-28526,
Addition of maleic anhydride to an isomerized olefin obtained by heating an α-olefin having 8 to 30 carbon atoms in the presence of a catalyst as exemplified in JP-A-58-45731 and JP-A-61-34298. It is reacted and used just before use by emulsifying with cationized starch, ionic vinyl copolymer or emulsifier.

As a rosin-based sizing agent, gum rosin, wood rosin or tall oil rosin or a rosin modified product obtained by heat-treating these with formaldehyde (anhydrous) is α, β-unsaturated with maleic acid, fumaric acid, acrylic acid, itaconic acid, citraconic acid, etc. After reacting with an acid, a solution-type rosin sizing agent neutralized with an alkali, or JP-A-47-20402,
JP-A-53-133259, JP-A-52-77206, JP-A-61-1
Emulsifying agents exemplified in 08796 and the like and, if necessary, an emulsion-type sizing agent emulsified using a solvent can be used. As the alkenyl succinate, a product obtained by adding maleic anhydride to a dimer to hexamer of olefin such as propylene, isobutylene or butylene and neutralizing the same with an alkali is used.

A known papermaking method is applied to the paper production method of the present invention. That is, the above-mentioned sizing agent is stirred and mixed into a pulp slurry together with other commonly used additives such as a filler, a dye, a fixing agent, and a paper strength agent. This stock is sent through a screen to the papermaking process.

The paper making process (paper machine) is usually made up of three divisions: a wire part, a press part, and a dry part. That is, a paper layer is formed in the wire part, water is squeezed in the press part, and dried in the dryer part. In the present invention, it is most important that the paper that has been pressed in the press part and then dried in the subsequent dry part is exposed to steam.

Once dried, the paper is subjected to a surface treatment with a size press, a gate roll coater, a bill coater, a calender or the like, and then dried again.

The steam used in the present invention may be either saturated steam or heated steam, but saturated steam is suitable. As the gauge pressure, saturated steam having a steam pressure of 0.1 to 6 kg / cm ² can be used. The time for which the paper is exposed to steam is not particularly limited, but the weight of steam received by the paper is 1 dry paper.
0.002 to 0.4 parts by weight per part by weight is suitable.

Further, the method of exposing the paper to steam in the present invention is not particularly limited, but a steam box (for example, a debronizer; used for adjusting the moisture profile and / or improving water squeezing by the press immediately before the press part). Debron Hercules) can be used effectively.

The place where the paper is exposed to steam is preferably such that the moisture content of the paper is low, and it is better after the press part and before the dryer part, the dryer part, or after the dryer part. Of these, after the dryer part is preferred. If a ketene dimer compound is used as a sizing agent and the size development is slow and the absorption of the size press solution is unnecessarily increased, it is best to expose the paper to steam after the dryer part and before the size press. ing.

Pulp raw materials used in the present invention include bleached or unbleached high-yield pulp such as bleached or unbleached chemical pulp, groundwood pulp, mechanical pulp, or thermomechanical pulp, such as kraft pulp or sulfite pulp, used paper, used paper for magazines, and corrugated cardboard. Either waste paper or waste paper pulp such as deinked waste paper can be used.

Additives such as fillers, dyes, dry paper strength improvers, wet paper strength improvers, retention aids and the like can be used as needed.

Further, starch, polyvinyl alcohol, dye, coating color, surface sizing agent, anti-slip agent and the like can be applied as required by a size press, gate roll coater, bill coater, calender or the like.

〔Example〕

Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, “%” means solid content% by weight, unless otherwise specified.
The amount of chemicals added is the solid content% by weight based on the absolutely dry pulp weight.
Indicated by

Example 1 20% of heavy calcium carbonate (Escalon 1500, manufactured by Sankyo Seiko Co., Ltd.) was added to 2.4% pulp slurry [BKP L / N = 8/2, Canadian Standard Freeness 380 ml] and stirred for 2 minutes. Thereafter, 0.75% of cationized starch (Kate F, manufactured by Oji Cornstarch Co., Ltd.) and bansulfate ± 0.5% were sequentially added, and the mixture was further stirred for 2 minutes. Next, the pulp slurry concentration was reduced to 0.
After dilution to 24%, a ketene dimer sizing agent (Harcon W,
Dic Hercules) 0.1%, Yield improver (High Reten 104, Dick Hercules) 0.02%
After stirring for 1 minute, a wet paper having a basis weight of 70 g / m ² was obtained with a hand-making apparatus manufactured by Noble & Wood. The papermaking pH was 8.0. The wet paper was pressed to a moisture content of 59.0%, and then dried at 80 ° C. for 70 seconds with a drum dryer. Immediately after drying, paper having a water content of 4.0% was obtained. Next, saturated steam having a gauge pressure of 0.5 kg / cm ² was sprayed on the paper immediately after drying for 1 second. From the change in the moisture content of the paper, the steam weight received by the paper was calculated to be 0.003 per absolute dry weight of the paper.

Immediately after and 7 days after spraying steam, the degree of Stekigt sizing was measured, and the results are shown in Table 1.

Examples 2 to 5 Saturated steam was sprayed for 10 seconds, 60 seconds, and 180 seconds.
The same operation as in Example 1 was performed except that the time was changed to seconds and 360 seconds. Table 1 shows the measurement results of the steam weight and sizing degree received by the paper. Example 4 is also shown in Tables 4 and 7 for reference.

Comparative Example 1 The same operation as in Example 1 was performed, but steam was not sprayed on the paper immediately after drying. The results are shown in Tables 1, 3, 4, and 7.

Examples 6 to 9 The same operation as in Examples 1 to 4 was performed except that Harcon 40C, 0.15% (manufactured by Dick Hercules) was used as a ketene dimer sizing agent. The results are shown in Table 2.

Comparative Example 2 The same operation as in Example 6 was performed, but no steam was sprayed on the paper immediately after drying. The results are shown in Table 2.

Examples 10 to 12 The same operation as in Example 1 was performed except that saturated steam having a gauge pressure of 0.1, 0.5, and 3.0 kg / cm ² was sprayed for 120 seconds. Table 3 shows the results.

Example 13 The same operation as in Example 4 was performed, except that the place where steam was sprayed was after pressing and before drying with a dryer. Table 4 shows the results.

Comparative Example 3 The same operation as in Example 1 was performed except that the place where steam was sprayed was wet paper having a moisture content of 88.5% before pressing. Table 4 shows the results.

Examples 14, 15 0.4% of amphoteric polyacrylamide-based paper strength enhancer (Epinox DS510, manufactured by Dick Hercules) was added to 2.4% pulp slurry [recycled corrugated paper, Canadian Standard Freeness 480 ml], and the mixture was stirred for 2 minutes. .

Then, after diluting the pulp slurry to 0.33%, a ketene dimer sizing agent (Harcon W 0.1% or Harcon 40 ° C 0.15%)
%) And stirred for 1 minute, followed by Noble &
A wet paper having a basis weight of 80 g / m ² was obtained using a hand-made paper machine manufactured by Wood Corporation. The papermaking pH was 7.0. This wet paper was dried with a drum dryer at 110 ° C. for 60 seconds after pressing. Immediately after drying, the paper was sprayed with saturated steam having a gauge pressure of 0.5 kg / cm ² for 60 seconds. Table 5 shows the results.

Comparative Examples 4 and 5 The same operation as in Examples 14 and 15 was performed, but steam was not sprayed on the paper immediately after drying. Table 5 shows the results.

Examples 16 and 17 The same operations as in Examples 14 and 15 were carried out except that NUKP, Canadian Standard Freeness 490 ml was used as the pulp. The results are shown in Table 6.

Comparative Examples 6 and 7 The same operations as in Examples 16 and 17 were performed, but steam was not sprayed on the paper immediately after drying. Table 6 shows the results.

Example 18 The same operation as in Example 4 was performed except that 0.1% of substituted cyclic dicarboxylic anhydride (size A-20, manufactured by Dick Hercules) was used as a sizing agent. Table 7 shows the results.

Comparative Example 8 The same operation as in Example 18 was performed, but no steam was sprayed on the paper immediately after drying. Table 7 shows the results.

Examples 19, 20, 21 0.5% solution rosin size (PFP, manufactured by Dick Hercules) or emulsion type rosin size in 2.4% pulp slurry [BKP L / N = 8/2, Canadian Standard Freeness 380 ml] 0.5% (Newfour 100, manufactured by Dick Hercules) or 0.5 alkenyl succinate (NSP, manufactured by Misawa Ceramic Chemicals)
%, Followed by sulphate ± 2.0% and stirred for 2 minutes. Next, after diluting the pulp slurry to 0.24%, a polyacrylamide-based paper strength agent (Epinox RS631, manufactured by Dick Hercules) was added at 0.05%, and the mixture was stirred for 1 minute, and then ground with a Noble & Wood hand-making apparatus. 65g /
m ² wet paper was obtained. The papermaking pH was 4.5. After the wet paper was pressed, it was dried at 100 ° C. for 50 seconds with a drum dryer. Immediately after drying, the paper was sprayed with saturated steam having a gauge pressure of 0.5 kg / cm ² for 60 seconds. Table 8 shows the results.

Comparative Examples 9, 10, and 11 The same scanning as in Examples 19, 20, and 21 was performed, but no steam was sprayed on the paper immediately after drying. Table 8 shows the results.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-137293 (JP, A) JP-A-62-177277 (JP, A) JP-A-62-223388 (JP, A) JP-A-58-1983 36296 (JP, A) JP 45-40682 (JP, B1) (58) Fields investigated (Int. Cl. ⁶ , DB name) D21H 17/00-17/74 D21F 7/00-11/00

Claims (3)

(57) [Claims] A press part for producing paper sized using at least one sizing agent selected from a ketene dimer compound, a substituted cyclic dicarboxylic anhydride, a rosin sizing agent and an alkenyl succinate. Exposing the paper to steam at a location after being pressed in step (1) and before the size press. 2. The paper according to claim 1, wherein the place after the paper is pressed in the press part is a place after the paper is dried in the dryer part and before the size press. Production method. 3. The sizing agent is a ketene dimer compound represented by the following general formula (I).
The method for producing the paper as described above. (However, R ₁ and R ₂ in the formula (I) each have 8 to 30 carbon atoms.
Represents a hydrocarbon group).