JPH09217292A - Calcium carbonate-filled paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a calcium carbonate-filled paper excellent in optical characteristics such as opacity and whiteness, good in balance of the optical characteristics with physical characteristics such as tensile strength and paper body strength, further capable of adjusting the extent of the above balance, having a high quality and inexpensive. SOLUTION: This calcium carbonate-filled paper contains 5-35 pts.wt. calcium carbonate mixture of a spindle shaped calcium carbonate and a pillar-shaped calcium carbonate based on 100 pts.wt. bone dry weight of a raw material pulp. The weight ratio of the spindle-shaped to a pillar-shaped is preferably (95:5)-(40:60). Further, based on 100 pts.wt. bone dry weight, 5-35 pts. mixture of calcium carbonate consisting of (95:5)-(40:60) weight ratio of the spindle-shaped to the pillar-shaped calcium carbonate and 0.1-10 pts.wt. titanium oxide are preferably contained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention is excellent in optical properties such as opacity and whiteness, and the balance between such optical properties and physical properties such as tensile strength and stiffness of paper. The present invention relates to a high-quality and inexpensive calcium carbonate-filled paper which is good and is capable of adjusting the degree of this balance, which is a coated base paper such as art paper and coated paper, PPC paper, and thermal paper. , Pressure sensitive paper, thermal transfer paper, inkjet paper, electrostatic recording paper, magnetic recording paper and other information paper, high-grade printing paper, intermediate printing paper and other uncoated printing paper,
It is preferably used as an industrial hybrid paper, especially as back carbon paper, Indian paper or rice paper, which tends to cause a difference in performance of the internal filler.

[0002]

2. Description of the Related Art In the field of thin paper such as back carbon paper, Indian paper and rice paper, fillers such as calcium carbonate, titanium dioxide and calcined clay have been used to improve the opacity and whiteness of the paper. Has been. Regarding the calcium carbonate, the opacity of the thin paper containing the calcium carbonate is related to its particle shape and dispersibility, so that various particle shapes have been proposed according to the purpose of use.

For example, it has been proposed to increase the opacity by using columnar calcium carbonate, reduce the amount of other fillers such as titanium dioxide and calcined clay, and reduce the cost of thin paper (JP-A-57-71499). Japanese Patent Laid-Open No. 62-282099).

However, when columnar calcium carbonate is added, the rigidity of the thin paper is lower than when spindle-shaped calcium carbonate is added, and the manufacturing process is complicated and the manufacturing cost is higher than that of spindle-shaped calcium carbonate. Since it has the drawback of being bulky, spindle-shaped calcium carbonate is used in ordinary thin paper, and the lack of opacity is supplemented with titanium dioxide or calcined clay, but the combined amount is increased to obtain the required physical properties. In reality, it is inevitable that the cost will increase because it is necessary.

[0005]

Under the above circumstances, the present invention has excellent optical properties such as opacity and whiteness even if titanium dioxide or calcined clay is not used together or the amount used is reduced. And also with such optical characteristics,
Aiming to provide a high-quality and inexpensive calcium carbonate infill paper that has a good balance with physical properties such as tensile strength and paper stiffness, and that can adjust the degree of this balance. It was made.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to develop a calcium carbonate-filled paper having good properties as described above, and as a result, a mixture of columnar calcium carbonate and spindle-shaped calcium carbonate. Further, it was found that the object can be achieved by using a mixture obtained by further adding a small amount of titanium dioxide to the mixture as the case may be, and the present invention has been completed based on this finding.

That is, the present invention relates to pulp raw materials,
A calcium carbonate mixture of spindle-shaped calcium carbonate and columnar calcium carbonate 5 to 35 per 100 parts by weight of the absolute dry weight.
The present invention provides a calcium carbonate-filled paper which is characterized by containing parts by weight.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The pulp raw material of the present invention can be arbitrarily selected from the pulps generally used as papermaking raw materials according to the purpose of use. Examples of such pulp include cotton pulp, flax pulp, hemp pulp, kozo, mitsumata, goosehide pulp, manila hemp pulp, straw pulp, bagasse pulp, various wood pulps, waste paper pulp, and mixed pulp thereof. However, for thin paper, flax pulp, hardwood pulp, softwood pulp, hemp pulp and other plant pulps and mixed pulps thereof are suitable. In the present invention, a mixture of spindle-shaped calcium carbonate and columnar calcium carbonate is used as a compounding ingredient in the pulp raw material.

The spindle-shaped calcium carbonate used in the present invention is not particularly limited, but the major axis of SEM particles is 0.5 to 3.
0 μm, the minor axis is 0.1 to 0.5 μm, the 50% cumulative particle size of the laser type particle size distribution is 2.5 to 4.5 μm, and the residue passing through the 325 mesh sieve is 0.005% or less, The degree of wire wear is preferably 100 mg or less, and more preferably the aspect ratio is 2-10. Further, those mainly composed of calcite are preferable, and the other crystal morphology is a scalenohedron.
ns) is also used. Those mainly composed of calcite include those consisting of calcite alone.
The minor axis of the spindle-shaped calcium carbonate means the maximum width in the thickness direction.

The columnar calcium carbonate may be either aragonite type or calcite type, which is SEM.
The particle size has a major axis of 0.5 to 3.0 μm and a minor axis of 0.1.
0.3 μm, 50% cumulative particle size of laser type particle size distribution is 2.5 to 4.5 μm, 325 mesh sieve passing residue is 0.005% or less, and wire abrasion degree is 50.
It is preferably mg or less, and more preferably an aspect ratio of 3 to 30. Further, those mainly composed of aragonite are preferable, and acicular ones are also used. Those mainly composed of aragonite also include those composed solely of aragonite.

The calcium carbonate mixture used in the present invention is particularly advantageous in that the SEM particle size has a major axis of 0.5 to 0.5.
3.0 μm, minor axis 0.1-0.5 μm, 50% cumulative particle size of laser type particle size distribution 2.5-4.5 μm, 325 mesh sieve residue 0.005% or less Yes, the wire wear rate is 100 mg or less, and spindle-shaped calcium carbonate mainly composed of calcite and SE
The major axis of the M particles is 0.5 to 3.0 μm, and the minor axis is 0.1.
0.3 μm, aspect ratio 3 to 30, 50% cumulative particle size of laser type particle size distribution is 2.5 to 4.5 μm.
m, the residue passing through a 325 mesh sieve is 0.005% or less, the wire abrasion degree is 50 mg or less, and a mixture with columnar calcium carbonate mainly containing aragonite. The spindle-shaped calcium carbonate preferably has an aspect ratio of 2 to 10.

In the calcium carbonate mixture used in the present invention, the preferred blending ratio of the spindle-shaped calcium carbonate and the columnar calcium carbonate is selected within a weight ratio of 95: 5 to 40:60, particularly 80:20 to 40:60. Be done. If the proportion of spindle-shaped calcium carbonate is higher than this,
The wire wear rate during papermaking is high, and the opacity of the obtained paper is low. As a compounding method, the spindle-shaped calcium carbonate and the columnar calcium carbonate can be added to the pulp raw material in a premixed state, or the spindle-shaped calcium carbonate and the columnar calcium carbonate can be separately added to the pulp raw material. .

In the present invention, the blending ratio of the mixture of spindle-shaped calcium carbonate and columnar calcium carbonate is 5-35 parts by weight, preferably 5-30 parts by weight, based on 100 parts by weight of the dry weight of pulp material. It is necessary to mix in the ratio. If the blending ratio is less than this, sufficient whiteness and opacity cannot be obtained, and if it is more than this, the cost increases. Further, in the present invention, titanium dioxide can be further used as a blending component in the pulp raw material. The mixing ratio of titanium dioxide at that time is 0.1 to 100 parts by weight of the dry weight of the pulp raw material.
It is necessary to mix 10 parts by weight, preferably 0.2 to 5.0 parts by weight. If the blending ratio is less than this, the whiteness and opacity peculiar to titanium dioxide will be insufficient, and if it is more than this, the cost will increase.

Titanium dioxide is several times more expensive than calcium carbonate, but is excellent in opacity and whiteness, so that it is often used as a filler component for papermaking. The amount used varies depending on the type of paper, application, required physical properties, etc., but is usually in the range of 10 to 30% by weight in the total filler. In the present invention, by using columnar calcium carbonate and spindle-shaped calcium carbonate in combination, even if the amount of titanium dioxide used is reduced to 5 to 15% by weight, which is half of the usual case, the same physical properties as in the usual case are obtained. Is obtained.
If desired, part of this titanium dioxide can be converted to calcined clay.

In the present invention, in addition to these components, various addition components which have been conventionally used for internal filler paper can be blended within a range that does not impair the original purpose thereof. As the additive component, a sizing agent, for example, a neutral sizing agent such as an alkyl ketene dimer or an alkenyl succinic anhydride or a neutral rosin, an acidic sizing agent such as an acidic rosin or a petroleum sizing agent, a yield improving agent such as polyacrylamide, Examples include size fixing agents such as cationic starch and sulfuric acid bands, and paper strengthening agents such as corn starch.

The calcium carbonate-filled paper of the present invention is produced by a conventional method, for example, by mixing pulp and the above-mentioned filler in a predetermined ratio and adding water, a sizing agent and an appropriate additive component. Can be manufactured by.

The calcium carbonate-filled paper of the present invention is preferably constructed so that the ash content remaining when it is finally burned out in an electric furnace is 40% by weight or less and the pH is 7 to 10.

[0018]

EFFECTS OF THE INVENTION According to the present invention, excellent opacity and whiteness are exhibited without using titanium dioxide or calcined clay, and when spindle type calcium carbonate alone or columnar type calcium carbonate alone is used as a filler. The drawbacks such as low opacity, low tensile strength and weak stiffness of paper are improved, and it shows a good balance of the required properties as a desired paper, and the degree of this balance is adjusted. (For example, opacity is emphasized relatively more than tensile strength), and by adding a smaller amount of titanium dioxide if desired, titanium dioxide can be added in a usual amount. It is possible to provide an inner paper having excellent whiteness, opacity and rigidity which are almost comparable to those described above. The calcium carbonate-filled paper is coated base paper such as art paper and coated paper, information paper such as PPC paper, thermal paper, pressure-sensitive paper, thermal transfer paper, inkjet paper, electrostatic recording paper, magnetic recording paper, and the like. It is suitable as non-coated printing paper such as high-grade printing paper and intermediate-grade printing paper, especially copy base paper such as back carbon paper which tends to cause a difference in performance of the internal filler, thin paper printing paper such as India paper, and rice paper.

[0019]

The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention. Each physical property of the samples in Examples and Comparative Examples was determined according to the following measuring methods or evaluation criteria. (1) Components in paper: Measured according to JIS P8128 (2) Tensile strength: Measured according to JIS P8113 (3) Breaking length: Measured according to JIS P8113 (4) Whiteness: Measured according to JIS P8123 (5) Opacity: Measured according to JIS P8138 (6) pH in paper: Measured according to JIS P8133

Reference Example Calcite-based spindle-shaped calcium carbonate (Okutama Kogyo TP-121SA) and aragonite-based columnar calcium carbonate (Okutama Kogyo TP-123FS)
Were mixed in a weight ratio of 90:10, 70:30 or 50:50 to prepare mixed calcium carbonate having the physical properties shown in Table 1.

For comparison, Table 1 also shows individual physical properties of calcite-based spindle-shaped calcium carbonate and aragonite-based columnar calcium carbonate. Each physical property in the table is measured by the following method. (1) Concentration: Measured using an infrared moisture meter. (2) Viscosity: Measured using a B-type viscometer. (3) 50% particle size: Based on laser type particle size distribution (50% cumulative particle size). (4) 325 mesh sieve residue: 325 mesh sieve,
Measured by the wet method. (5) Wire abrasion degree: Measured with an abrasion tester (plastic wire) manufactured by Nippon Filcon. (6) pH: Measured by the glass electrode method. (7) Specific surface area: measured by BET.

[0022]

[Table 1]

Examples 1 to 3, Comparative Examples 1 to 2 Hardwood kraft pulp (350 csf) and softwood kraft pulp (450 csf) were mixed in a weight ratio of 7: 3 to 100 parts by weight of a pulp raw material, and the mixture obtained in the reference example was mixed. 18 parts by weight of calcium carbonate A to C and 2 parts by weight of anatase type titanium dioxide are blended, and further 0.5 parts by weight of cationized starch as a paper strengthening agent, 0.2 parts by weight of alkyl ketene dimer as a neutral sizing agent, and yield. India paper was manufactured by adding 0.02 part by weight of polyacrylamide as an improver and hand-making using a square sheet machine. Table 2 shows the physical properties of this product.

Example 4 TP-121SA (trade name, spindle type, manufactured by Okutama Kogyo Co., Ltd.) Calcite-based calcium carbonate) 60% by weight, TP-123FS (trade name, manufactured by Okutama Industry Co., Ltd., columnar aragonite-based calcium carbonate) 30% by weight, and KRONOS-KA10 (trade name, manufactured by Titanium Industry Co., Ltd., anatase titanium dioxide). 20 parts by weight of a filler composed of 10% by weight is added, and further 0.5 parts by weight of cationized starch (paper strengthening agent), 0.2 parts by weight of alkali ketene dimer (neutral sizing agent) and polyacrylamide (yield improving agent). India paper is manufactured by adding 0.02 parts by weight and hand-making using a square sheet machine. did. Table 2 shows the physical properties of this product.

COMPARATIVE EXAMPLE 1 The filler was 80% by weight of TP-121SA and KRONOS.
-India paper was produced in the same manner as in Example 4 except that the content of KA10 was changed to 20% by weight. Table 2 shows the physical properties of this product.

Example 5 A back carbon paper was prepared in the same manner as in Example 4.
Table 2 shows the physical properties of this product.

Comparative Example 2 80% by weight of TP-121SA and KRONOS were used as the filler.
A back carbon paper was manufactured in the same manner as in Example 5 except that the content of KA10 was changed to 20% by weight. Table 2 shows the physical properties of this product.

Example 6 TP-12 was added to 100 parts by weight of flax pulp (80csf).
Rice paper was manufactured by adding a filler composed of 70% by weight of 1SA and 30% by weight of TP-123FS and hand-making using a square sheet machine. Table 2 shows the physical properties of this product.

Comparative Example 3 Rice paper was produced in the same manner as in Example 6 except that the filler was changed to one consisting only of TP-121SA.
Table 2 shows the physical properties of this product.

Comparative Example 4 95% by weight of TP-121SA and KRONOS were used as the filler.
-Rice paper was produced in the same manner as in Example 6 except that 5% by weight of KA10 was used. Table 2 shows the physical properties of this product.

[0031]

[Table 2]

From the above, the inner filler paper of the present invention of each embodiment is
It can be seen that the desired properties required for the paper have a good balance between optical properties such as opacity and whiteness and physical properties such as tensile strength and stiffness of paper. Also, comparing Example 6 with Comparative Examples 3 and 4, the one containing only the calcium carbonate mixture of the present invention as the filler showed excellent opacity and whiteness without using titanium dioxide together, and compared with Example 4 Comparing Comparative Example 1 and Example 5 with Comparative Example 2, even if the compounding amount of titanium dioxide was small, the physical properties almost equal to those of the conventional ordinary compounding compounding the compounding amount thereof were obtained, It can be seen that expensive titanium dioxide can be replaced at least in part by columnar calcium carbonate, which can reduce the cost of producing the desired paper. Further, according to Examples 1 to 4, optical properties such as opacity and whiteness and physical properties such as tensile strength were obtained by changing the ratio of spindle-shaped calcium carbonate and columnar calcium carbonate in the required properties as a desired paper. It is possible to make the opacity more important than the tensile strength as in Example 3 or the tensile strength as more important than the opacity as in Example 1 by relatively varying the dynamic characteristics. Therefore, it can be seen that the degree of balance between both characteristics can be adjusted.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Toru Kawazu 10-11-7 Kawabe-cho, Ome-shi, Tokyo Rafine 106 Kawabe

Claims (6)

[Claims] 1. An absolutely dry weight of pulp material of 100.
A calcium carbonate-filled paper containing 5 to 35 parts by weight of a calcium carbonate mixture of spindle-shaped calcium carbonate and columnar calcium carbonate per part by weight. 2. The calcium carbonate-filled paper according to claim 1, wherein the weight ratio of the spindle-shaped calcium carbonate and the columnar calcium carbonate is 95: 5 to 40:60. 3. The absolute dry weight of pulp raw material is 100.
5 to 35 parts by weight of (A) spindle-shaped calcium carbonate and columnar calcium carbonate in a weight ratio of 95: 5 to 40:60, and (B) 0.1 to 10 parts by weight of titanium dioxide. Calcium carbonate infill paper characterized in that 4. The calcium carbonate mixture has a SEM particle size with a major axis of 0.5 to 3.0 μm and a minor axis of 0.1 to 0.5 μm.
and the 50% cumulative particle size of the laser particle size distribution is 2.
5 to 4.5 μm, 325 mesh sieve residue is 0.005% or less, and wire wear degree is 100 mg
The following spindle-shaped calcium carbonate, the SEM particle size has a major axis of 0.5 to 3.0 μm, a minor axis of 0.1 to 0.3 μm, an aspect ratio of 3 to 30, and a laser type particle size distribution. 50% cumulative particle size is 2.5 to 4.5 μm, and 3
The calcium carbonate-filled paper according to claim 1, 2 or 3, which is a mixture with columnar calcium carbonate having a 25 mesh sieve residue of 0.005% or less and a wire abrasion degree of 50 mg or less. 5. The calcium carbonate-filled paper according to claim 1, wherein the calcium carbonate mixture is a mixture of spindle-shaped calcium carbonate mainly composed of calcite and columnar calcium carbonate mainly composed of aragonite. 6. The calcium carbonate-filled paper according to claim 1, which is a copy base paper, a thin printing paper or a rice paper.