JP2003239196A - Surface-sized pressed paper using amphoteric starch with low viscosity - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-sized pressed paper having an improved surface strength compared to the one obtained by using a conventional starch by using an inexpensive starch as a surface-treating agent, and having an improved strength against printing and abrasion. <P>SOLUTION: The sized pressed paper is obtained by coating a specific surface-treating agent on the surface of a base paper, and drying the coated paper. The surface-treating agent consists essentially of an amphoteric starch obtained by adding urea and inorganic phosphoric acids to a cationic starch having 0.005-0.06 substitution degree with a cationic group and a tertiary amine and/or a quaternary ammonium salt so that the pH of the slurry after the mixing is ≤5.0, and reacting the mixture by a dry roast process. The amphoteric starch has ≥0.0005 substitution degree of an anionic group (phosphate group), and provides 15% pasty liquid having ≤500 mPa.s viscosity by a B-type viscometer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a size press paper having an excellent printability by coating the surface of paper with a specific low-viscosity amphoteric starch to improve the surface strength.

[0002]

2. Description of the Related Art Recently, papers mainly composed of mechanical pulp and used paper pulp have been used as a printing paper, and in particular, it is demanded to use a large amount of used paper from the viewpoint of environmental problems such as increase of dust and resource saving. There is. The number of printing papers containing a large amount of chemical pulp as in the past is also decreasing, and the strength of the paper itself is also decreasing. Further, many paperboards, gypsum board base papers, and the like contain a large amount of waste paper pulp of poor quality, and fluffing or peeling of the paper surface due to rubbing causes damages due to a decrease in the surface strength of the paper.

Furthermore, in recent years, offset printing, color printing, and high speed printing have been rapidly progressing, and there is a demand for superior color printing suitability and printing workability with respect to printing paper as a printing medium. Offset printing is a method in which dampening water and ink are supplied to the printing plate, and then the ink is transferred to a rubber plate called a blanket and then transferred to paper to perform printing. The printing paper is required to have a high surface strength because it uses a printing ink having a relatively high tack as compared with the method. If the surface strength is weak, there is a problem of so-called blanket piling, in which fibers loosened from the paper due to paper peeling, fillers and paper powder contained in the printing paper are deposited on the blanket, and when they are mixed with the ink, printing on the paper surface So-called scratches and the like occur on the surface, and troubles such as deterioration of print quality and deterioration of printing workability occur.

As described above, the demand for improving the surface strength against printing and rubbing is increasing with time. As a measure for improving the surface strength, conventionally, water-soluble polymers such as starch, polyvinyl alcohol, and polyacrylamide have been applied to the surface of paper as a surface treatment agent. Among them, polyvinyl alcohol and polyacrylamide, which are synthetic polymer compounds, are expensive and costly, and thus tend to be avoided. As a starch of a natural polymer compound, an oxidized starch or a self-modified starch in which the viscosity of starch is reduced with an enzyme, an acid, an oxidizing agent or the like is often used, but the effect of improving the surface strength is smaller than that of a synthetic polymer compound. In addition, since starch is cheap, it is possible to increase the coating amount to improve the surface strength. However, if the coating amount is increased, paper curling occurs due to starch expansion and contraction of the paper surface coating layer and the paper surface gets wet. When it becomes, it tends to increase the stickiness of the paper surface, which is called nepparability.
With regard to nepparability, problems with blanket piling during offset printing, paper sticking to the blanket during printing and causing wrinkles and paper breaks, paper-to-paper or paper-to-other objects storage It is easy to cause problems such as sticking.

The surface strength is improved by using inexpensive starch,
As an example of improving printability, Japanese Patent Laid-Open No. 16289/1989
There are JP-A No. 5 and JP-A No. 7-243192, but these utilize enzyme modification of acetic acid esterified starch and cationic etherified starch. However, none of them has been able to sufficiently cope with the decrease in paper strength due to the current increase in the content of waste paper and the increase in printing load due to the speeding up of printing.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a size press paper in which inexpensive starch is used as a surface treatment agent, which has improved surface strength as compared with conventional starch and improved strength against printing and rubbing. Is. In the present invention, amphoteric starch is used as the surface treatment agent, but if it has a small amount of a cationic group, it has a function of easily binding to anionic paper fibers and firmly binding the fibers, and after the coating, During the drying process, water-soluble polymers such as starch migrate, which is a phenomenon in which the water-soluble polymer that has penetrated from the paper surface to the inside of the paper migrates to the paper surface again as the water evaporates. It is considered that since they are bound, this migration can be suppressed, a uniform starch film layer can be easily formed on the paper surface, and the surface strength can be improved. Further, by having an anion group at the same time, the pH of the paste solution can be stabilized in a wide range,
The paste solution is stable even if an anionic reagent is added, and the operability during size press is improved. Furthermore, since these cation groups and anion groups react with and bind to the hydroxyl groups of starch, they are also considered to be useful for improving the aging property of starch and suppressing the decrease in the binder effect of starch. However, various surface size presses of amphoteric starch were investigated, but not all were effective.

[0007]

The present inventors reviewed the utilization of starch as a surface treatment agent for paper, and as a result of diligent research, as a result of using a specific low-viscosity amphoteric starch, the surface strength of paper was improved. We have identified a dramatic improvement,
The present invention has been completed.

That is, the present invention includes the following inventions. (1) Urea and inorganic phosphates so that the slurry pH after mixing with cationic starch having a tertiary amine and / or quaternary ammonium salt with a degree of substitution of cationic groups of 0.005 to 0.06 is 5.0 or less. Is added, and then the reaction is carried out by a dry roasting method to obtain an anion group (phosphate group) substitution degree of 0.0005 or more, and a paste liquid B type viscosity (60 rpm, 50 ° C.) of 15%. A size press paper obtained by applying a surface treatment agent containing amphoteric starch as a main component of 500 mPa · s or less to the surface of the base paper and drying it. (2) The size press paper according to (1) above, wherein the amphoteric starch is obtained by adding an inorganic acid and / or an organic acid in addition to urea and inorganic phosphoric acid, and then reacting it by a dry roasting method. . (3) The size press paper according to (1) or (2) above, wherein the inorganic phosphoric acid is at least one selected from the group consisting of orthophosphoric acid and alkali metal salts and alkaline earth metal salts of inorganic phosphoric acids.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a surface treatment agent containing amphoteric starch as a main component which satisfies the following conditions A to C is used. A: A cationic starch having a tertiary amine and / or a quaternary ammonium salt having a cationic group substitution degree of 0.005 to 0.06 is used. B: Anion group (phosphoric acid group) obtained by adding urea and inorganic phosphoric acid, and optionally a small amount of inorganic acid and / or organic acid to the cationic starch, and then performing a roasting reaction by a dry roasting method. Amphoteric starch having a degree of substitution of 0.0005 or more. C: 15% size liquid of the amphoteric starch B type viscosity (60 rpm,
50 ° C) is 500 mPa · s or less.

Usually, in order to obtain a low-viscosity amphoteric starch, an anionic group is introduced into a cationic starch to obtain an amphoteric starch, and the amphoteric starch is subjected to a low-viscosity treatment with an acid, an oxidizing agent or an enzyme. A characteristic of the low-viscosity amphoteric starch used in the present invention is that phosphorylation (introduction of anion group) and viscosity reduction are simultaneously performed by roasting a cationic starch using urea and inorganic phosphoric acid. Although no clear structural difference between the low-viscosity amphoteric starch used in the present invention and other low-viscosity amphoteric starch is known, a clear difference appears in the effect of improving the surface strength when the surface size is pressed. .

The amphoteric starch used in the size press paper of the present invention will be described in detail below. Examples of the raw material starch of the amphoteric starch used in the present invention include raw starch such as corn starch (corn starch), waxy corn starch, potato starch, tapioca starch, wheat starch, sweet potato starch, rice starch, and raw starch thereof. If the hydroxyl groups necessary for the subsequent cationization and phosphoric acid esterification remain, chemically modified starch in which substituents such as acetylation, hydroxyethylation, and hydroxypropylation are introduced by a known method, or acid modification It is possible to use starch or the like whose viscosity has been lowered (lower molecular weight) in advance by oxidation or the like. Further, these starches can be used in combination of two or more kinds.

In producing the amphoteric starch used in the present invention, first, the raw material starch is cationized. The cationization may be performed by any known technique,
As the cationizing agent, tertiary amines such as diethylaminoethyl chloride, quaternary ammonium salts such as 3-chloro-2-hydroxypropyltrimethylammonium chloride, glycidyltrimethylammonium chloride and the like are preferably used. For cationization,
Usually, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide are used.

The cationic group substitution degree of the cationic starch is 0.0
It is necessary to be 05 to 0.06, and preferably 0.005 to 0.05. The degree of substitution is 0.005
If it is less than 0.05, the effect of the present invention is low, and if it exceeds 0.06, the reaction becomes difficult and the cost increases, which is not practical.

Subsequent to cationization, a low-viscosity amphoteric starch is obtained by simultaneously performing low-viscosity and phosphoric esterification by roasting treatment using urea and inorganic phosphoric acid. When producing an amphoteric starch, an anionic group must be introduced into the cationic starch, but a phosphoric acid ester group is preferably used in terms of cost and workability.

In the present invention, the dry roasting method is used as the roasting reaction method. The dry roasting method is a known method described in JP-B-45-20512, and specifically, a starch is impregnated with a mixed solution of a reaction reagent and water, or a high concentration of the reaction reagent is used. After impregnating the solution with starch, or spray-spraying the mixed solution or high-concentration solution onto starch, stirring the mixture until it becomes uniform, and then stirring the mixture with a stirring dryer, a static dryer or the like. It is used to carry out a heating reaction.

As a method for introducing a phosphate ester group, a phosphate salt such as sodium tripolyphosphate is added alone to carry out a roasting reaction to introduce a phosphate ester group, or urea is used together with inorganic phosphates. There is a method of adding and introducing a phosphoric acid ester group and a carbamate ester group (not an anion group) by a roasting reaction. The amphoteric starch used in the present invention is obtained by the latter method of urea phosphorylation treatment in which an inorganic phosphoric acid and urea are roasted and reacted.

In the former method in which the phosphate is added alone and roasted, the pH at the time of the reaction is set to 5.5 or more, and therefore the viscosity is not lowered. In order to use it for size press, it is necessary to further reduce the viscosity by acid, oxidation, enzyme treatment, etc. after the phosphoric acid esterification reaction, which not only causes disadvantages in cost and workability, but also With the low-viscosity amphoteric starch obtained by various production methods, the effect of improving the surface strength of the size-pressed paper in the present invention cannot be obtained.

In the latter method, the viscosity of the starch is reduced at the same time when the phosphate ester group is introduced, which is advantageous in cost and workability. Furthermore, the effect of improving the surface strength of the size-pressed paper in the present invention can be obtained only by the amphoteric starch in which the phosphate ester group is introduced and the viscosity is reduced by the latter method.

Examples of the inorganic phosphoric acid used in the present invention include orthophosphoric acid (orthophosphoric acid), pyrophosphoric acid,
Tripolyphosphoric acid, hexametaphosphoric acid, and their alkali metal salts (for example, sodium salt, potassium salt) and alkaline earth metal salts (for example, calcium salt, magnesium salt) and ammonium salt, specifically sodium dihydrogen phosphate, Examples thereof include sodium tripolyphosphate and ammonium hydrogenphosphate, which may be used alone or in combination of two or more kinds.

The rate of addition of inorganic phosphoric acid and urea to the cationic starch is 0.2 to 5.0 when the inorganic phosphoric acid is added to the starch solid content.
%, And urea is preferably 0.5 to 10.0% by weight, and a small amount (within 50 mol% with respect to the inorganic phosphoric acid) of an inorganic acid other than the inorganic phosphoric acid (for example, hydrochloric acid, Sulfuric acid, nitric acid) and / or organic acids (eg formic acid, acetic acid, oxalic acid) can be added. Similarly, in order to control viscosity, a small amount (within 50 mol% of inorganic phosphates) of an inorganic base (eg sodium hydroxide, potassium hydroxide, ammonia), an organic base (eg methylamine, ethylamine, dimethylamine, hexamethylene). A diamine) can be added. In addition, care must be taken so that the pH of the 10% slurry when the inorganic phosphoric acid, urea, and (if necessary, other acid or base) is mixed with the cationic starch is 5.0 or less. If the pH during mixing is high, the lowering of the molecular weight is difficult to proceed and the target viscosity is not lowered. The pH
Is preferably 1.5 to 3.5. Inorganic phosphates,
After dissolving urea, (and a small amount of other acid or base) in water,
The cationic starch is uniformly impregnated and mixed. Any known method can be used for impregnating and mixing the chemicals as long as they can be uniformly mixed. After impregnation and mixing, water content is 15% by weight by air flow drying
The following is preferably dried to 6% by weight or less, but the drying method is not particularly limited.

After drying, the mixture is put into a roasting reactor and the temperature is 110 to 180
The roasting reaction is carried out at ℃ for several minutes to several hours. If the roasting temperature is too low, the phosphoric acid esterification is difficult to proceed, and if it is too high, a coloring reaction occurs and the commercial value is reduced. The roasting reaction conditions (roasting temperature, roasting time) depend on the amount of inorganic phosphoric acid, urea, (other acids) added, the type of roasting reactor and the required quality (phosphate ester group amount, viscosity, etc.). Selected appropriately.

The degree of substitution of the phosphoric acid ester group is 0.0005.
It is necessary to be more than 0.0005-0.08
Is preferred. If it is less than 0.0005, it becomes difficult to obtain the viscosity stability (aging effect) as amphoteric starch and the viscosity stability over a wide range of pH. If it exceeds 0.08, the reaction becomes difficult and the cost increases, which is not practical.

The viscosity after completion of the roasting reaction is required to be 500 mPa · s or less at 15% glue liquid B type viscosity (60 rpm, 50 ° C.), and if it is higher than this, the coating for size press is performed. Becomes very difficult and not practical. The 15% glue liquid B type viscosity (60 rpm, 50 ° C.) is 10 to 1
It is preferably 50 mPa · s. Next, the production of the size press paper in the present invention will be described.

The size press paper of the present invention is obtained by applying a surface treatment agent to a base paper. The surface treatment agent used in the present invention is
The low-viscosity amphoteric starch as a main component, as an optional component, for example, in addition to other adhesives, various auxiliary agents such as defoaming agents, water resistance agents, surface sizing agents, preservatives, fluorescent dyes, etc., Inorganic pigments, organic pigments and the like for improving the opacity and whiteness of the paper and the ink absorbency can be appropriately blended. Examples of the other adhesives include various modified starches, latexes such as styrene-butadiene copolymers, polyvinyl alcohol and polyacrylamide. The ratio of the low-viscosity amphoteric starch to the total solids in the surface treatment agent is usually 50 to 100% by weight, preferably 60.
The total solid content concentration in the surface treatment agent is appropriately adjusted depending on the coating apparatus and the target coating amount, but is usually in the range of 2 to 30% by weight.

The surface treatment agent obtained as described above is
Coating devices generally used in the papermaking field, such as gate roll coaters, 2 roll size presses, rod metalling size presses, blade metalling size presses, blade coaters, bar coaters, rod blade coaters, air knife coaters, curtain coaters, etc. It is applied to one side or both sides of the raw paper surface by using an appropriate device. The coating amount when applying the surface treatment agent using such an apparatus is preferably 0.05 g / solid-side conversion per one side.
It is desirable to coat and dry so that m ² or more, and more preferably 0.05 to 5 g / m ² . By the way 0.0
When the amount is less than 5 g / m ² , the sizing agent coating on the surface of the paper is insufficient and the fibers, fillers, etc. in the paper cannot be fixed with the sizing agent and the effect of improving the surface strength cannot be obtained. On the other hand, if it is applied so as to exceed 5 g / m ² , not only the cost becomes high, but also another problem such as neppar may occur. In addition, after the surface treatment agent is applied and dried, it can be passed through a calendar and subjected to pressure treatment and smoothing treatment, if necessary.

The base paper is not particularly limited, and those requiring surface strength improvement by a surface size press, such as newsprint, information paper, coated base paper, liner paper,
It is possible to use various types of high-quality papers or medium-quality papers such as various paperboards, flame-retardant base papers, gypsum board base papers, postcard papers, printing writing papers, foam papers, PPC papers, inkjet papers and the like, which are acidic, neutral or alkaline papermaking.

[0027]

The present invention will be described in more detail with reference to Examples and Comparative Examples, but the scope of the present invention is not limited to the following Examples. In the following, parts and% are parts by weight and% by weight, respectively, unless otherwise specified. (Example 1) To 100 parts of tapioca starch, 150 parts of water was added and dissolved, and the mixture was heated to 40 ° C. After adding 3% aqueous sodium hydroxide solution to pH 11.5 and adding 5.8 parts of 3-chloro-2-hydroxypropyltrimethylammonium chloride as a quaternary ammonium salt cationizing agent, while maintaining the temperature and pH. After reacting for 16 hours, pH
Was set to 6.0 to terminate the reaction. After the completion of the reaction, the slurry was dehydrated, washed and dried to obtain a cationic starch having a water content of 12%. The amount of nitrogen of the obtained cationic starch was measured by the Kjeldahl method, and the degree of substitution of the quaternary ammonium salt was calculated to be 0.040.

Next, 0.85 parts of orthophosphoric acid and 3.2 of urea.
15 parts of water was dissolved in 15 parts of water to obtain a drug solution, and 100 parts of the cationic starch obtained above was impregnated and mixed so that the drug solution and the starch were uniform. The 10% slurry pH of this mixture was 2.3. Then, after drying with a hot air heater until the water content becomes 5%, a roasting reaction is performed by heating at 130 ° C. for 30 minutes with the same hot air heater, and phosphoric acid esterification (anionization) is performed. At the same time, the viscosity was reduced. After the obtained low-viscosity amphoteric starch (amphoteric starch A) was purified with hydrochloric acid-water-methanol 1: 1, the amount of bound phosphorus was measured by the Fiske-Suvaroe method to calculate the degree of substitution of the phosphate ester group. The B-type viscosity was measured by heating a 15% slurry with stirring at 95 ° C. for 30 minutes, cooling to 50 ° C., and using a Brookfield viscometer at 60 rpm at the 15th rotation. The results are shown in Table 1.

In addition, 2 of the low viscosity amphoteric starch obtained above
The 0% slurry was heated and gelatinized at 95 ° C. for 30 minutes with stirring, and then diluted with water until a starch solution having a starch solid content of about 5% was prepared to prepare a surface treating agent. Using a 2-roll size press machine, apply both sides to uncoated neutral neutral paper (basis weight 65 g / m ² ) so that the weight after drying will be 2.0 g / m ^2, and dry with a drum dryer. After that, 1-nip treatment was performed with a soft calendar to obtain size press paper.

RI printing strength of the obtained size press paper,
The results of the wax pick strength are shown in Table 2. In addition, the wax pick strength is based on JAPAN TAPPI Paper Pulp Test Method No. The test was performed based on the wax pick strength test method A of 1. Also, the RI printing strength is PRIN on the RI printing machine.
TING INK SMX T.I. V. = 18 (printing test ink, manufactured by Toyo Ink Co., Ltd.) was used for printing, and the state of paper peeling after printing was visually observed, and relative evaluation was performed in 10 grades, with 1 being poor and 10 being excellent.

(Example 2) In the production of the size press paper of Example 1, a surface treatment agent was dried on uncoated neutral neutral paper (basis weight 65 g / m ² ) using a 2-roll size press. A size press paper was obtained in the same manner as in Example 1 except that both sides were coated so that the weight afterward was 1.5 g / m ² .

Example 3 100 parts of tapioca starch and 1 part of water
50 parts was added and melt | dissolved, and it heated at 40 degreeC. After adding 3% aqueous sodium hydroxide solution to pH 11.5 and adding 2.5 parts of 3-chloro-2-hydroxypropyltrimethylammonium chloride as a quaternary ammonium salt cationizing agent, while maintaining the temperature and pH. After reacting for 16 hours, the pH was adjusted to 6.0 to terminate the reaction. After the completion of the reaction, the slurry was dehydrated, washed and dried to obtain a cationic starch having a water content of 12%. The amount of nitrogen in the obtained cationic starch was measured by the Kjeldahl method, and the degree of substitution of the quaternary ammonium salt was calculated to be 0.018.

Next, 0.8 parts of orthophosphoric acid and 2.7 parts of urea were dissolved in 15 parts of water to prepare a drug solution, and 100 parts of the cationic starch obtained above was impregnated and mixed so that the drug solution and the starch were uniform. . The 10% slurry pH of this mixture was 2.2. Then, after drying with a hot-air heater until the water content becomes 5%, a roasting reaction is performed by heating at 150 ° C. for 30 minutes with the same hot-air heater to form a phosphoric acid ester (anionization). At the same time, the viscosity was reduced to obtain a low-viscosity amphoteric starch (amphoteric starch B). A size press paper was obtained in the same manner as in Example 1 except that the starch obtained above was used as a surface treatment agent.

Example 4 100 parts of tapioca starch and 1 part of water
50 parts was added and melt | dissolved, and it heated at 40 degreeC. While adding 3% aqueous sodium hydroxide solution to pH 11.5 and adding 1.1 parts of 3-chloro-2-hydroxypropyltrimethylammonium chloride as a quaternary ammonium salt cationizing agent, while maintaining the temperature and pH. After reacting for 16 hours, the pH was adjusted to 6.0 to terminate the reaction. After the completion of the reaction, the slurry was dehydrated, washed and dried to obtain a cationic starch having a water content of 12%. The amount of nitrogen in the obtained cationic starch was measured by the Kjeldahl method, and the substitution degree of the quaternary ammonium salt was calculated to be 0.007.

Next, 1.0 part of orthophosphoric acid and 2.9 parts of urea were dissolved in 15 parts of water to prepare a drug solution, and 100 parts of the cationic starch obtained above was impregnated and mixed so that the drug solution and the starch were uniform. . The 10% slurry pH of this mixture was 2.1. Then, after drying with a hot air heater until the water content becomes 5%, a roasting reaction is carried out by heating at 145 ° C. for 30 minutes with the same hot air heater, and phosphoric acid esterification (anionization) is performed. At the same time, the viscosity was reduced to obtain a low-viscosity amphoteric starch (amphoteric starch C). A size press paper was obtained in the same manner as in Example 1 except that the starch obtained above was used as a surface treatment agent.

Example 5 0.45 parts of orthophosphoric acid, 0.08 part of hydrochloric acid, and 3.2 parts of urea were dissolved in 15 parts of water to prepare a chemical solution, and 100 parts of the cationic starch prepared in Example 1 was mixed with the chemical solution. The starch was mixed by impregnation so as to be uniform. The 10% slurry pH of this mixture was 2.5. Then, after drying with a hot air heater until the water content becomes 5%, a roasting reaction is carried out by heating at 125 ° C. for 35 minutes with the same hot air heater, and phosphoric acid esterification (anionization) is performed. At the same time, the viscosity was reduced to obtain a low-viscosity amphoteric starch (amphoteric starch D). A size press paper was obtained in the same manner as in Example 1 except that the starch obtained above was used as a surface treatment agent.

(Example 6) 1.1 parts of orthophosphoric acid, urea 2.
8 parts was dissolved in 15 parts of water to prepare a drug solution, and 100 parts of the cationic starch prepared in Example 1 was impregnated and mixed so that the drug solution and the starch were uniform. 10% slurry p of this mixture
H was 2.0. Then, using a hot air heater, the water content becomes 5
After drying until it reaches 40%, 140% with the same hot air heater
A roasting reaction was carried out by heating at 40 ° C. for 40 minutes to reduce the viscosity at the same time as phosphoric acid esterification (anionization) to obtain a low-viscosity amphoteric starch (amphoteric starch E). A size press paper was obtained in the same manner as in Example 1 except that the starch obtained above was used as a surface treatment agent.

Example 7 To 100 parts of corn starch was added 150 parts of water to dissolve it, and the mixture was heated to 40 ° C. After adding 3% aqueous sodium hydroxide solution to pH 11.5 and adding 5.8 parts of 3-chloro-2-hydroxypropyltrimethylammonium chloride as a quaternary ammonium salt cationizing agent, while maintaining the temperature and pH. After reacting for 16 hours, the pH was adjusted to 6.0 to terminate the reaction. After the completion of the reaction, the slurry was dehydrated, washed and dried to obtain a cationic starch having a water content of 12%. The amount of nitrogen in the obtained cationic starch was measured by the Kjeldahl method, and the degree of substitution of the quaternary ammonium salt was calculated to be 0.038.

Then, 0.85 parts of orthophosphoric acid and 3.7 of urea
15 parts of water was dissolved in 15 parts of water to obtain a drug solution, and 100 parts of the cationic starch obtained above was impregnated and mixed so that the drug solution and the starch were uniform. The 10% slurry pH of this mixture was 2.4. Then, after drying with a hot air heater until the water content becomes 5%, a roasting reaction is carried out by heating at 145 ° C. for 30 minutes with the same hot air heater, and phosphoric acid esterification (anionization) is performed. At the same time, the viscosity was reduced to obtain a low-viscosity amphoteric starch (amphoteric starch F). A size press paper was obtained in the same manner as in Example 1 except that the starch obtained above was used as a surface treatment agent.

(Example 8) To 100 parts of corn starch, 150 parts of water was added and dissolved, and the mixture was heated to 40 ° C. While adding 3% aqueous sodium hydroxide solution to pH 11.5 and adding 1.1 parts of 3-chloro-2-hydroxypropyltrimethylammonium chloride as a quaternary ammonium salt cationizing agent, while maintaining the temperature and pH. After reacting for 16 hours, the pH was adjusted to 6.0 to terminate the reaction. After the completion of the reaction, the slurry was dehydrated, washed and dried to obtain a cationic starch having a water content of 12%. The amount of nitrogen in the obtained cationic starch was measured by the Kjeldahl method, and the substitution degree of the quaternary ammonium salt was calculated to be 0.007.

Then, 0.85 parts of orthophosphoric acid and 3.7 of urea
15 parts of water was dissolved in 15 parts of water to obtain a drug solution, and 100 parts of the cationic starch obtained above was impregnated and mixed so that the drug solution and the starch were uniform. The 10% slurry pH of this mixture was 2.4. Then, after drying with a hot air heater until the water content becomes 5%, a roasting reaction is carried out by heating at 145 ° C. for 30 minutes with the same hot air heater, and phosphoric acid esterification (anionization) is performed. At the same time, the viscosity was reduced to obtain a low-viscosity amphoteric starch (amphoteric starch G). A size press paper was obtained in the same manner as in Example 1 except that the starch obtained above was used as a surface treatment agent.

Comparative Example 1 A size press paper was obtained in the same manner as in Example 1 except that Ace A (oxidized starch A; manufactured by Oji Corn Starch) was used as the starch used as the surface treatment agent.

Comparative Example 2 Ace A (oxidized starch A; manufactured by Oji Corn Starch) was used as the starch used as the surface treatment agent.
In the production of the size press paper of Example 1, the surface treatment agent was applied to the uncoated neutral neutral quality paper (basis weight 65 g / m ² ) using a 2-roll size press to obtain a weight of 1.5 g / m ²
A size press paper was obtained in the same manner as in Example 1 except that both sides were coated so that

(Comparative Example 3) 0.7 part of sodium tripolyphosphate was dissolved in 15 parts of water to prepare a drug solution, and 100 parts of the cationic starch prepared in Example 1 was impregnated and mixed so that the drug solution and the starch were uniform. The 10% slurry pH of this mixture was 7.5. Then, after drying with a hot air heater until the water content becomes 5%, 1 with the hot air heater
A roasting reaction was carried out by heating at 40 ° C. for 60 minutes to perform phosphoric acid esterification (anionization). After the reaction,
The mixture was neutralized with water containing a small amount of hydrochloric acid, washed to remove excess salt, and dried to obtain amphoteric starch. Orthophosphoric acid 0.2
10 parts of water was dissolved in 10 parts of water to prepare a drug solution, and 100 parts of the amphoteric starch obtained above was impregnated and mixed so that the drug solution and the starch were uniform. The 10% slurry pH of this mixture was 2.6. Next, after drying with a hot air heater until the water content becomes 5%, heating and roasting is performed with the same hot air heater at 125 ° C. for 30 minutes to reduce the viscosity by acid modification to obtain a low viscosity amphoteric starch. (Amphoteric starch H) was obtained.

In addition, 2 of the low viscosity amphoteric starch obtained above
Ammonia water is added to 0% slurry to adjust pH to 6, and gelatinized by heating at 95 ° C for 30 minutes with stirring, and then diluted with water until a starch solution having a starch solid content of about 5% is obtained, and then a surface treatment agent. Was prepared. A size press paper was obtained in the same manner as in Example 1 except that the surface treating agent obtained above was used.

Comparative Example 4 0.7 part of sodium tripolyphosphate was dissolved in 15 parts of water to prepare a drug solution, and 100 parts of the cationic starch prepared in Example 7 was impregnated and mixed so that the drug solution and the starch were uniform. The 10% slurry pH of this mixture was 7.5. Then, after drying with a hot air heater until the water content becomes 5%, 1 with the hot air heater
A roasting reaction was carried out by heating at 40 ° C. for 60 minutes to perform phosphoric acid esterification (anionization). After the reaction,
The mixture was neutralized with water containing a small amount of hydrochloric acid, washed to remove excess salt, and dried to obtain amphoteric starch. Orthophosphoric acid 0.2
10 parts of water was dissolved in 10 parts of water to prepare a drug solution, and 100 parts of the amphoteric starch obtained above was impregnated and mixed so that the drug solution and the starch were uniform. The 10% slurry pH of this mixture was 2.6. Then, after drying with a hot air heater until the water content becomes 5%, the product is roasted and baked for 40 minutes at 125 ° C. with the same hot air heater to reduce the viscosity by acid modification to give a low viscosity amphoteric starch. (Amphoteric starch I) was obtained.

In addition, 2 of the low-viscosity amphoteric starch obtained above is used.
Ammonia water is added to 0% slurry to adjust pH to 6, and gelatinized by heating at 95 ° C for 30 minutes with stirring, and then diluted with water until a starch solution having a starch solid content of about 5% is obtained, and then a surface treatment agent. Was prepared. A size press paper was obtained in the same manner as in Example 1 except that the surface treating agent obtained above was used.

Comparative Example 5 0.2 part of orthophosphoric acid was dissolved in 15 parts of water to prepare a drug solution, and 100 parts of the cationic starch prepared in Example 1 was impregnated and mixed so that the drug solution and the starch were uniform. The 10% slurry pH of this mixture was 2.6. Then, after drying with a hot air heater until the water content becomes 5%, heating and roasting is performed at 120 ° C. for 30 minutes with the same hot air heater to reduce the viscosity by acid modification to obtain a low viscosity cation. A starch (cationic starch A) was obtained.

20 of the low-viscosity cationic starch obtained above
Ammonia water is added to the 5% slurry to adjust the pH to 6 and gelatinized by heating at 95 ° C for 30 minutes with stirring, and then diluted with water until a starch solution having a starch solid content of about 5% is obtained, and a surface treatment agent is prepared. Prepared. A size press paper was obtained in the same manner as in Example 1 except that the surface treating agent obtained above was used.

Comparative Example 6 0.2 parts of orthophosphoric acid was dissolved in 15 parts of water to prepare a chemical solution, and 100 parts of the cationic starch prepared in Example 7 was impregnated and mixed so that the chemical solution and the starch were uniform. The 10% slurry pH of this mixture was 2.6. Then, after drying with a hot air heater until the water content becomes 5%, heating and roasting is performed at 120 ° C. for 40 minutes with the same hot air heater to reduce the viscosity by acid modification to obtain a low viscosity cation. A starch (cationic starch B) was obtained.

20 of the low-viscosity cationic starch obtained above
Ammonia water is added to the 5% slurry to adjust the pH to 6 and gelatinized by heating at 95 ° C for 30 minutes with stirring, and then diluted with water until a starch solution having a starch solid content of about 5% is obtained, and a surface treatment agent is prepared. Prepared. A size press paper was obtained in the same manner as in Example 1 except that the surface treating agent obtained above was used.

Comparative Example 7 0.8 parts of orthophosphoric acid, 5.
8 parts was dissolved in 15 parts of water to prepare a drug solution, and tapioca starch was impregnated and mixed so that the drug solution and the starch were uniform. The 10% slurry pH of this mixture was 2.8. Then, after drying with a hot-air heater until the water content becomes 5%, a roasting reaction is performed by heating at 140 ° C. for 30 minutes with the same hot-air heater, and phosphoric acid esterification (anionization) is performed. At the same time, the viscosity was reduced to obtain a low-viscosity phosphoric acid ester starch (phosphoric acid starch A). A size press paper was obtained in the same manner as in Example 1 except that the starch obtained above was used as a surface treatment agent.

[0053]

[Table 1]

[Table 2]

As is apparent from Table 2, according to the present invention, it is possible to provide a size press paper which has an extremely improved surface strength and can withstand high-load printing.

[0055]

EFFECTS OF THE INVENTION According to the present invention, it is possible to provide a size press paper in which inexpensive starch is used as a surface treating agent and which has improved surface strength as compared with conventional starch and improved strength against printing and rubbing. .

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4L055 AG48 AH13 AH37 AH50 AJ02                       BE08 FA13 FA15 GA16 GA17                       GA18 GA34

Claims (3)

[Claims] 1. A cationic group substitution degree of 0.005 to 0.06.
Urea and inorganic phosphoric acid are added to the cationic starch having a tertiary amine and / or a quaternary ammonium salt of 1 such that the slurry pH after mixing is 5.0 or less, and then the mixture is reacted by a dry roasting method to obtain The anion group (phosphate group) substitution degree is 0.0005 or more, and the paste liquid B is 15%.
A size press paper obtained by applying a surface treatment agent containing amphoteric starch as a main component having a mold viscosity (60 rpm, 50 ° C.) of 500 mPa · s or less on the surface of a base paper and drying the paper. 2. The size-pressed paper according to claim 1, wherein the amphoteric starch is obtained by adding an inorganic acid and / or an organic acid in addition to urea and an inorganic phosphoric acid and then reacting it by a dry roasting method. . 3. The size press paper according to claim 1, wherein the inorganic phosphoric acid is at least one selected from the group consisting of orthophosphoric acid and alkali metal salts and alkaline earth metal salts of inorganic phosphoric acids.