JPS6017880B2 - Coating materials for papermaking - Google Patents

Description

[Detailed description of the invention] The present invention relates to a coating material for paper manufacturing.

More specifically, the present invention provides a papermaking coating material containing a resin component, a pigment, and an optical brightener selected from the group consisting of alkali cellulose, ethylene oxide, and y-butyrolactone, propane sultone, and mono/chloroacetic acid. The average number of added moles per glucose unit of ethylene oxide obtained by reacting at least one anionizing agent is 0.8 or more, and the degree of substitution per glucose unit of the anionizing agent is 0.1 or more. The present invention relates to a papermaking coating material further containing a certain anionic cellulose derivative. The anionic cellulose derivative blended in the present invention is a novel substance that has been disclosed in the literature, and the inventor has already filed an application for a method for producing such an anionic cellulose derivative (Japanese Patent Application No. 53
No. 1139055).

As a result of further research on the anionic cellulose derivative, the present inventor found that in a papermaking coating material containing a resin component, a pigment, and an optical brightener, the papermaking coating material further contains the anionic cellulose derivative. It was found to be extremely effective and was published. The present invention was completed based on this knowledge. The papermaking coating material of the present invention has all the properties desired as a papermaking coating material.

That is, the papermaking coating material containing the above-mentioned anionic cellulose derivative has excellent water retention, brightening properties, protective colloidal properties,
It has various properties such as oil resistance, binder properties, and coating properties. Here, water retention refers to the property that water does not separate from the resin components or pigments in the papermaking coating material even when the papermaking coating material is heated. Fluorescent whitening property refers to a property that further improves the whitening effect of a fluorescent whitening agent. The term "protective colloidal property" refers to the property of an anionic cellulose conductor forming a protective colloid to stably disperse various components in a papermaking coating material in water.
Oil resistance refers to the property of preventing oil from penetrating from the surface to the back surface of paper treated with a papermaking coating material. Furthermore, the term "binder property" refers to a property in which the resin components and pigments in the papermaking coating material do not adhere to and separate from the paper surface treated with the papermaking coating material. Furthermore, even when calcium carbonate is used as a white pigment when preparing the papermaking coating material of the present invention, no aggregation effect commonly referred to as shock occurs, and therefore the preparation of the papermaking coating material is extremely difficult. It becomes easy to coat, and the coatability can be greatly improved. The reason for the above effect is not clear at present and is currently under investigation, but it is likely that the anionic cellulose derivative is adsorbed onto the surface of the pigment particles and forms a charged ion layer in the aqueous phase surrounding the particles through the action of polyanions. However, it is presumed that this prevents reaggregation with calcium carbonate and provides a fluid and stable dispersion. The anionic cellulose derivative blended into the papermaking coating material of the present invention is, for example, alkali cellulose, ethylene oxide, and at least one anionizing agent selected from the group consisting of y-butyrolactone, propanesultone, and monochloroacetic acid. It is produced by reacting.

As the alkali cellulose used as the starting material, a wide variety of known alkali celluloses can be used, such as alkali cellulose 1, alkali cellulose 2, alkali cellulose m, and the like. In the present invention, alkali cellulose 1
It is preferable to use Alkaline cellulose 1 is a highly reactive cotton-like substance, and its composition is approximately 25% of cellulose.
~45% by weight (hereinafter simply expressed as "%" unless otherwise specified), sodium hydroxide approximately 5-25%, water approximately 40-6%
It is 0%. The amount of ethylene oxide used as the other starting material is generally 1 mol or more, preferably 1 mol or more per mol of glycose unit in the alkali cellulose.
The amount is preferably about 5 moles. The anionizing agent used as the other starting material is y-butyrolactone,
At least one selected from the group consisting of propane santhone and monochloroacetic acid. The amount of anionizing agent to be added is generally 0.2 mol or more, preferably about 0.3 to 1 mol, per mol of glucose units in the alkali cellulose. In this reaction, the alkali cellulose, ethylene oxide and anionizing agent may be reacted simultaneously, or the alkali cellulose may be first reacted with ethylene oxide and then the anionizing agent may be reacted with the alkali cellulose. Further, the above reaction may be carried out without a solvent or in a suitable solvent. Specific examples of the solvent include hydrophilic organic solvents such as acetone, methanol, ten-butyl alcohol, and inpropyl alcohol, and the use of such solvents allows for more uniform reaction. The reaction temperature is generally about 25 to 80 qo. When the reaction is carried out in a solvent, it is preferable to carry out the reaction near the boiling point of the solvent.
After the reaction is complete, the
- It is purified by washing with a mixture of water and a hydrophilic organic solvent such as butyl alcohol or isopropyl alcohol, and then dried and pulverized to produce a product. Coating agent for paper manufacturing of the present invention (
There is no particular limitation on the molecular weight of the anionic cellulose derivative to be blended into the composition (hereinafter referred to as "composition of the present invention"), but the higher the molecular weight is blended, the more the viscosity of the composition of the present invention increases. The composition may be appropriately selected and used so that the composition of the present invention has an appropriate viscosity during use. In addition, the amount of anionic cellulose derivative to be blended is the molecular weight of the anionic cellulose derivative used,
It varies depending on the type of fluorescent brightener and the amount used, etc., but it cannot be generalized, but it is usually 0.1 to 1.5 parts by weight (hereinafter simply referred to as "parts") of the pigment 10 in the composition of the present invention. degree,
It is preferable to add about 0.3 to 0.5 parts. In the present invention, the average number of moles of ethylene oxide added per glycose unit is 0. 1. An anionic cell which is on a scale and has a degree of substitution per glucose unit of an anionizing agent of 0.1 or more. - Among the carbon dioxide conductors, the average number of moly added per glycose unit of ethylene oxide is 1.4 or more, and the degree of substitution per glycose unit of the anionizing agent is 0. Preferably, anionic cellulose derivatives are used. As pigments to be blended into the composition of the present invention, any pigments commonly used in this field can be used; specifically, wollin clay for coating, titanium dioxide, aluminum hydroxide, calcium carbonate, and barium sulfate. Examples include inorganic pigments such as , magnesium oxide, talc, satin white, zinc oxide, and silica.

In the present invention, a small amount of an organic pigment may be added to such an inorganic pigment. The amount of pigment to be blended into the composition of the present invention is not particularly limited and may be selected within a wide range, but it is usually about 20 to 76 parts, preferably 25 to 76 parts per 100 parts of the composition of the present invention. It is best to mix it to the same extent as in Japan.
As the resin component to be mixed into the composition of the present invention, a wide range of resins commonly used in this field can be used, such as styrene-butadiene synthetic resins, vinyl acetate synthetic resins, and ethylene-vinyl acetate synthetic resins. Examples include water-soluble synthetic polymer substances such as , methyl methacrylate-toptagene synthetic resins, synthetic proteins, and water-soluble natural polymer substances such as casein, oxidized starch, dextrin, modified starch, gelatin, and vegetable gum.

The amount of the resin component to be blended into the composition of the present invention is not particularly limited and may be appropriately selected within a wide range, but is usually about 5 to 2 parts per 10 parts of pigment, preferably 8 parts. It is preferable to mix about 15 parts. As the photobrightener to be incorporated into the composition of the present invention, a wide variety of known ones can be used as long as they are water-soluble. Examples of such optical brighteners include those based on diaminostilbene sulfonate, specifically Whitex BKconc.
Examples include [trademark, manufactured by Sumitomo Chemical ■], Whitex BRF [trademark, manufactured by Sumitomo Chemical ■], Kikor BRAL [trademark, manufactured by Nisso Kako ■], and Cyahor PAS [trademark, manufactured by Nippon Kayaku ■]. There is no particular limit to the amount of optical brightener to be added, and it may be selected within a wide range, but usually pigment 10
About 0.1 to 1 part, preferably 0.2 to 0, based on Makoto Ikari.
．． It is best to mix about 5 parts. The composition of the present invention may further contain a dispersant, an antifoaming agent, a curing agent, a preservative, a release agent, a coloring dye, a coloring pigment, etc., as required.

There are no particular limitations on the production of the composition of the present invention, and a wide range of methods commonly used in this field can be employed. For example, the above-mentioned various components may be mixed with a thin layer. There are no particular restrictions on the use of the composition of the present invention, and conventional methods of using papermaking coating materials can be applied as is.

For example, applying the composition of the present invention onto paper that requires treatment,
Next, a method of drying this can be mentioned. As a coating method, a wide range of ordinary methods can be applied, such as air knife coater, blade coater, roll coater,
This can be easily done using a size press coater, spray coater, cast coater, etc. Further, as the drying method, a wide range of ordinary methods can be employed, such as natural drying, air drying, heating, and the like. Examples of manufacturing the anionic cellulose derivative used in the present invention are listed below as reference examples, and further examples are listed.

Reference example: Pulverized alkali cellulose (NaOH 15%
, cellulose content: 35%, water content: 50%) was charged into a kneader-type reactor equipped with a counterflow condenser, sealed, and replaced with nitrogen gas.
A mixed solution of Y-butyrolactone 86 and Y-butyrolactone was added little by little.

Make sure that the reaction temperature does not exceed 60qo and the pressure is 2k9.
The amount added was adjusted so as not to exceed the amount of carp, and the mixture was added by pouring water while being careful to cool the mixture. After the addition was completed, the reaction temperature was further increased to 60 qC, and the reaction was completed while maintaining the temperature at this temperature. Next, the jacket is cooled, and the temperature of the reaction system is 3
When the cleaning solvent reached 500 ml (composition: methanol 5
5%, acetone 35%, water 10%) add 1500 ml of
After heating in the wind, it was filtered by centrifugal separation. In the same manner, it was purified by washing five times with a solvent of the same composition. It was then dried and crushed to make a product. The product yield was 282 pieces. The product dissolves transparently in water. A portion of the aqueous solution was placed in a test tube and heated to the boiling point, but it did not gel. Next, sulfuric acid was added to make it acidic, but it did not gel. Hydrochloric acid or acetic acid was used instead of sulfuric acid. The same thing happened when adding . Similarly, an aqueous solution of calcium chloride was added, but no insoluble gel was formed. Separately, a portion of the aqueous solution was applied to a glass plate and dried, yielding a transparent and flexible film. The analytical values of the product are as follows.

Moisture: 4% Ash: 9.4% (as Na2C03) Viscosity: 45 specific ps (2% aqueous solution, 2000) pH: 7.
2 (2% aqueous solution, 20qo) number of moles of ethylene oxide added;
1.8 mol Degree of substitution of y-butyrolactone: 0.5 Example: Add sodium polyacrylate (trademark, Aron T-40, manufactured by Toagosei ■) as a dispersant to 53.5 mol of water for 1 hour and stir for several minutes. After that, 85 ml of kaolin clay was gradually added to the mixture, and then 15 ml of calcium carbonate was gradually added.

After the addition, heating was continued for another 1 hour to prepare a pigment dispersion with a solid content of 65%. Next, 30 minutes of a 20% starch aqueous solution was gradually added, and when the solution became homogeneous, it was laticized (trademark, SN-307, manufactured by Sumitomo Naugatakku ■).
Add 20 minutes of water and continue lighting the lamp for 10 minutes after addition. then 5%
Anionic cellulose derivative (obtained in the above reference example) 102 was added, light was continued for 10 minutes after addition, and finally 2.5% optical brightener [trademark, WhitexBK
com (manufactured by Sumitomo Chemical Co., Ltd.)] was added, and after the addition, stirring was continued for 30 minutes to prepare a paper manufacturing coating agent 234.5 with a solid content of 50%. At that time, no aggregation effect called shock was observed, and the viscosity showed a low value (30 ps, 2yo).

It also had excellent water retention (by the furnace paper method). Base paper: Shiraoshi, [manufactured by Daishowa Paper Corporation]
A wire rod snake. 12 (coating amount: 17.
When the whiteness was measured after drying in the air for 1 night, it was found that the whitening effect of the fluorescent whitening agent was further improved.

Claims (1)

[Claims] 1. In a papermaking coating material containing a resinous component, a pigment, and a fluorescent brightener, at least one anion selected from the group consisting of alkali cellulose, ethylene oxide, γ-butyrolactone, propanesultone, and monochloroacetic acid. An anionic cellulose derivative in which the average number of moles added per glucose unit of ethylene oxide obtained by reacting an anionizing agent is 0.8 or more, and the degree of substitution per glycose unit of the anionizing agent is 0.1 or more. A coating material for paper manufacturing characterized by further blending.