JPH0813394A - Production of watermarked paper - Google Patents

Abstract

PURPOSE:To produce a watermarked paper having excellent distinctness of the watermark while keeping the required paper properties such as physical strength, printability and handling. CONSTITUTION:This watermarked paper is produced by using a paper material having a freeness of 200-400mL C.S.F. and composed of 1-10wt.% of a finely fibrillated cellulose having a number-average fiber length of 0.05-0.3mm and a water retention value of >=250% and 90-99wt.% of a vegetable fiber pulp. The paper material is produced either by beating a mixture of the finely fibrillated cellulose and the vegetable fiber pulp to a prescribed freeness or by beating a vegetable fiber pulp to a freeness of about 450-700mL C.S.F. and adding a finely fibrillated cellulose to get the prescribed freeness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a see-through paper. More specifically, the present invention relates to a method for producing a transparent paper in which transparent patterns such as patterns and characters can be made clear and the quality of the paper does not deteriorate.

[0002]

2. Description of the Related Art It has been widely practiced to provide a paper with a see-through for the purpose of imparting designability and anti-counterfeiting performance.
As is well known, the manufacture of such transparent paper is
A net-making machine that uses a net-making paper machine that uses a paper net made of bamboo, synthetic resin, or other pattern shapes such as patterns or letters attached to the surface of the mesh, or a paper net that has the mesh filled with resin It has been carried out by attaching it as the upper net of a cylinder cylinder or a dunny roll of a Fourdrinier paper machine.
When the former papermaking net is used, the fibers are pushed away by the convex portion to which the pattern shape is attached, and as a result, the paper layer at that portion becomes thin and a see-through pattern appears. When the latter papermaking net is used, the mesh of the pattern-shaped part is blocked and the passage of the stock material is suppressed. As a result, the paper layer at that part becomes thin and a see-through pattern appears. .

The quality of the show-through paper is primarily evaluated by the "sharpness" of the show-through. The "sharpness" is obtained by the abrupt change in the thickness of the paper layer between the portion where the pattern or the character is transparent and the portion where the transparent portion is not applied. If this change in thickness is gentle, the design and letters become unclear, and the quality of the show-through deteriorates.

According to the results of studies conducted by the present inventors, what has a great influence on the "sharpness" is the fiber length and the fiber thickness of the wood pulp used for the paper stock, and the shorter fiber length is longer than the longer fiber length. It was also found that a thin fiber can give clearer clearness than a thick fiber. The reason for this is that if the fibers of the wood pulp in the stock become shorter or thinner, the water retention of the stock is improved, and especially if the water retention of the stock in the wire part of the papermaking machine is improved, the fibers are densely patterned. It is thought that the "sharpness" of the transparent pattern is improved as a result of being deposited on the surface and reproducing the pattern well.

In the production of transparent paper, in addition to the clarity of the transparent paper described above, the quality of the paper, specifically, the physical strength of the paper, appropriate rigidity, printability, etc. are required. The fact is that the stock is prepared in consideration of these various conditions, and there is a constraint that only the clarity of the see-through cannot be considered.

[0006] As a method for improving the clarity of see-through, a method is considered in which beating wood pulp, which is generally used as a raw material, is advanced to shorten or thin pulp fibers.

The applicant has also proposed a method for clearing and making paper by using a stock material obtained by mixing a general pulp for papermaking with a special raw material such as whole kenaf pulp (Japanese Patent Application No. 5-79126). ).

[0008] Furthermore, a method for improving the retention of water in the wire part of the paper machine by adding polyethylene oxide, polyacrylamide, trourooi, etc. to the paper stock to increase the viscosity of the paper stock has also been conventionally used. It is being appreciated.

[0009]

However, in the case of making a clearing paper using a wood pulp in which pulp fibers are shortened or made thin by advancing the beating, the texture and the dimensional stability of the obtained clearing paper are improved. The properties of the paper other than the sharpness of the insert tend to deteriorate.

The method of mixing whole-stem kenaf pulp with paper stock has the advantage that clear clarity can be obtained without deteriorating the quality of the paper, but its use is limited because a special raw material is used. To be done.

Further, the method of adding a chemical such as polyethylene oxide to paper stock can improve the clarity of see-through, but has almost no effect on improving the physical strength and printability of paper. Also, if too much is used, a lot of bubbles will be generated for polyethylene oxide, which will adversely affect the quality of the paper. Furthermore, these chemicals have poor mechanical stability, and for example, when subjected to physical shearing force at the time of simultaneous beating with wood pulp or sending with a screw pump, the viscosity decreases remarkably, and the addition effect can hardly be expected. There is a constraint that it must be added to the stock just before papermaking.

Therefore, the present invention can effectively improve the clarity of the see-through paper without deteriorating the quality of the show-through paper such as physical strength, printability, and texture of the paper. Another object of the present invention is to provide an improved method for producing transparent paper.

[0013]

In order to solve the above-mentioned problems, the inventors of the present invention have made and evaluated clear paper using various raw materials for papermaking. And the present inventors focused on fine fibrillated cellulose having a high water-retaining power, as a result of advancing the study by producing a clearing paper using such fine fibrillated cellulose in combination with plant fiber pulp in various proportions, When a specific fine fibrillated cellulose is mixed with a plant fiber pulp at a specific ratio, and a clear paper is made using a stock having a specific freeness, a clear clear texture is obtained without deteriorating the quality of the paper. The inventors have found that they can be applied and completed the present invention.

That is, according to the method for producing the transparent paper according to the present invention, the number average fiber length is 0.05 to 0.3 mm and the water retention value is 25.
0% or more fine fibrillated cellulose 1 to 10% by weight
And 90 to 99% by weight of vegetable fiber pulp and a freeness of 200 to 400 ml C.I. S. F. It is characterized in that it is made into a paper using the above-mentioned paper material and is transparent.

The finely fibrillated cellulose used in the present invention is a finely fibrillated cellulose which is made into microfibrils by breaking the bundle of fibrils forming the cell walls of pulp fibers by a strong mechanical shearing force. In particular, in the present invention, the number average fiber length is 0.05 to
It is necessary to use fine fibrillated cellulose having a water retention value of 250% or more at 0.3 mm.

The number average fiber length is obtained by integrating the total length of fibers present in a given pulp suspension among the data measured by a fiber length measuring machine (FS-200 type) manufactured by KAJAANI (Finland), and then calculating the value. The value divided by the number is shown. The number average fiber lengths of bleached hardwood bleached kraft pulp and bleached softwood kraft pulp, which are the usual raw materials for paper, are about 0.5 mm and 1 mm, respectively, and even fibers fibrillated by the progress of beating have a number average fiber length. Is a minimum length of about 0.35 mm.

The reason for setting the number average fiber length of the fine fibrillated cellulose used in the present invention to 0.05 to 0.3 mm is that when it is less than 0.05 mm, the fine fibrillated cellulose itself is too small, and at the time of papermaking. The proportion of fine fibrillated cellulose washed out from the papermaking net increases. On the other hand, when the fine fibrillated cellulose having a number average fiber length of more than 0.3 mm is used, the desired improvement in the clarity of the obtained transparent paper cannot be achieved. In order to obtain clear paper that can be clearly seen through and does not deteriorate other quality of paper, use fine fibrillated cellulose having a number average fiber length of 0.1 to 0.2 mm. Is preferred.

The water retention value of fine fibrillated cellulose is an index of the degree of swelling of pulp, and the water retained and taken up in the swollen fiber and the free water existing in and between the fibers are separated by an appropriate centrifugal force. It is a value measured based on the idea that they can be distinguished. The water retention value specified in the present invention is based on the same concept, and is based on JAPAN TAPPI No.
26 is a value measured by the method specified by No. 26. That is, a predetermined amount of a sample mat is formed in advance on a specified filter, and after dehydrating for 15 minutes with a centrifugal force of 3000 G using a centrifuge, the retained water amount is divided by the absolute dry pulp amount. It shows the value at the time. Normal unbeaten pulp shows a water retention value of about 90%, and beaten pulp shows a water retention value of about 200%. The reason why the fine fibrillated cellulose is used in the present invention is because of its high water retention capacity. When the fine fibrillated cellulose having a water retention value of less than 250% is used, water in the wire part of the paper machine is used. The effect of improving the retention and improving the clarity of the see-through cannot be sufficiently obtained.

Various methods have been heretofore known as a method for producing fine fibrillated cellulose. In the present invention, even if fine fibrillated cellulose produced by any method is used, it has a predetermined number average fiber length and water retention. Anything that has a value can be used. For example, as a method for producing finely fibrillated cellulose by applying mechanical shearing force to cellulose fibers, a method using various beaters such as beater, conical refiner, single disc refiner, and double disc refiner is disclosed in JP-B-60-19921. By passing a suspension of fibrous cellulose, as proposed, through a small diameter orifice, imparting a high velocity to the suspension with a pressure differential of at least 3000 psi, which is then impinged to rapidly decelerate. Method for effecting cutting action, JP-A-63-2
A method of impacting a fiber material by rotating an impeller with a drive shaft with a hevel as proposed in No. 56787,
A method of dry micronization using a rotor and a hammer arranged in a housing as proposed in JP-A-4-82907, and a medium agitation wet pulverizer as proposed in JP-A-3-163135. Examples thereof include a method using a vibrating mill crushing device proposed in JP-A-6-10287, and a method using a fine crusher such as a sand mill proposed in JP-A-4-194097. In addition to the mechanical treatment, a method has also been proposed in which a chemical treatment such as an acid hydrolysis treatment, an alkali treatment, a liquid ammonia treatment, an enzyme treatment, and a steam treatment is combined with a mechanical treatment.

Examples of raw materials for fine fibrillated cellulose include chemical pulp such as bleached hardwood kraft pulp (LBKP), bleached softwood kraft pulp (NBKP), bleached sulphite hardwood (LBSP) and bleached softwood sulphite (NBSP). Or groundwood pulp (GP),
Wood pulp such as mechanical pulp such as thermo-mechanical pulp (TMP) can be used, and further, non-wood fiber pulp such as cotton pulp, hemp, bagasse, kenaf, espart, pomegranate, goose bark and sanpei, regenerated cellulose fiber, etc. can also be used. You can

The mixing ratio of the fine fibrillated cellulose and the vegetable fiber pulp is 1 to the fine fibrillated cellulose.
10% by weight and 90 to 99% by weight of vegetable fiber pulp.
The desired effect cannot be expected with a mixture containing less than 1% by weight of fine fibrillated cellulose. On the other hand, when a large amount of finely fibrillated cellulose is added, the drainage of the stock material is deteriorated, the water drainage in the wire part of the paper machine is deteriorated, and problems such as paper breakage easily occur. The upper limit of the amount of fine fibrillated cellulose added varies depending on the type of plant fiber pulp used as a raw material and its freeness, and for example, when using kenaf bast pulp with a high freeness as a raw material, fine fibrillated cellulose is used. Is added in an amount of more than 10% by weight, the freeness of the stock is 200 ml C.I. S.
F. It is further lowered, and the drainage is deteriorated. Further, when wood pulp is used as a raw material, if the fine fibrillated cellulose is added in an amount of more than 5% by weight, the drainage of the paper stock tends to deteriorate.

In carrying out the method of the present invention, first, a stock is prepared by mixing fine fibrillated cellulose and vegetable fiber pulp at a predetermined ratio. As the vegetable fiber pulp, those conventionally used conventionally can be used as well.
For example, not only chemical pulps such as LBKP, NBKP, LBSP, and NBSP, pulps including wood fibers such as mechanical pulps such as GP and TMP, but also straw, bamboo, espart,
Corn fiber, grass fiber such as bagasse, reed, kenaf, leaf fiber such as Manila hemp, sisal, pineapple leaf, flax, cannabis, ramie, jute, 楮, Sanpei, goose bark, etc.
Pulp composed of seed fiber such as cotton, linter, and kapok may be used, and these may be used alone or in combination of two or more kinds. If necessary, a small amount of synthetic fibers such as acrylic and vinylon, semi-synthetic fibers such as rayon and the like may be added.

A stock prepared by mixing fine fibrillated cellulose and vegetable fiber pulp is prepared, and then using a well-known beater such as beater, Jordan, refiner, etc.
Freeness 200-400 ml C.I. S. F. Continue refining until it reaches (Canadian standard freeness). The freeness of the stock is closely related to the clarity of the see-through. That is, the freeness is 400 ml C.I. S. F. At higher values, the beating is too shallow and the clarity of the see-through deteriorates. On the other hand, the freeness is 200 ml C.I. S. F. If it is lower than the above value, beating will proceed too much, resulting in poor dimensional stability of the resulting transparent paper and adversely affecting printability.

As described above, the plant fiber pulp may be beaten together with the fine fibrillated cellulose after mixing the plant fiber pulp with the fine fibrillated cellulose. S. F. Fine fibrillated cellulose was added to plant fiber pulp beaten to a certain degree to obtain a freeness of 200 to 400 ml C.I. S. F. May be An example of how the freeness is changed by adding the fine fibrillated cellulose is shown in the table below. In this example, a mixture of 30 parts by weight of NBKP and 70 parts by weight of LBKP was preliminarily drained to a water content of 520 m.
lC. S. F. And 660 ml C.I. S. F. The change in freeness when finely fibrillated cellulose was added in an amount varying from 1% by weight to 5% by weight to what was beaten in (1) was investigated.

Amount of finely fibrillated cellulose added (% by weight) 0 1 2 3 5 520 460 410 380 290 660 590 520 460 390 Unit: ml C.I. S. F.

In the above example, the freeness of 520 ml C.I. S.
F. In the case of the raw material pulp, the fine fibrillated cellulose is added in an amount of 3% by weight, and the freeness is 660 m.
lC. S. F. In the case of the raw material pulp of the above, the freeness of 400 ml C.I. S. F. It can be:

It should be noted that, if necessary, auxiliary materials for papermaking such as a wet paper strength enhancer, a dry paper strength enhancer, a sizing agent, a filler, a coloring agent and a fixing agent may be added to the paper stock.

The thus-obtained stock having a desired freeness is used in a conventionally known paper machine such as a Fourdrinier paper machine, a cylinder paper machine, a shortdrinier paper machine, and an inclined wire paper machine. Paper is usually made to have a basis weight of 50 to 200 g / m ² .

As in the conventional paper making net for making paper sheets on a paper machine, as in the conventional case, a pattern shape such as a pattern or a letter made of metal fine wire, bamboo cage, synthetic resin or the like is used as a mesh. It is possible to use a paper net attached to the surface or a paper net whose pattern is filled with resin etc. in a pattern shape.This can be attached as a cylinder cylinder of a cylinder paper machine or a dandy roll upper net of a Fourdrinier paper machine to make it transparent. Put in. Further, a pattern is stamped on the paper making net itself to make the net uneven, and the applicant of the present invention has disclosed that
It is also possible to adopt the method of attaching the race as the upper net as proposed in No. 185200.

The transparent paper produced by the method of the present invention is compared with a transparent paper produced from a stock having the same freeness mainly containing vegetable fiber pulp without adding fine fibrillated cellulose. Although the clarity of the show-through does not change, a paper having good physical properties such as physical strength, printability, and texture can be obtained. Alternatively, even when prepared into a stock having a lower freeness than the case of a conventional stock, by using the fine fibrillated cellulose together, the properties of the paper other than the clearness of clearing remain the same, A transparent paper with improved clarity of the transparent paper can be obtained. Such an effect is an effect obtained by adding fine fibrillated cellulose to plant fiber pulp.

The reason why such an effect is obtained is considered as follows. That is, since the water retention of the stock is dramatically improved by the addition of the fine fibrillated cellulose, when the beating degree of the plant fiber pulp itself is the same, the one to which the fine fibrillated cellulose is added is compared to the one without addition. The freeness becomes low. Therefore, for example, the freeness of 600 ml C.I.
S. F. Even with a degree of plant fiber pulp, the freeness of the whole mixture is 300 ml C.I. by adding fine fibrillated cellulose. S. F. It can be a degree. Therefore, add 300 ml of fine fibrillated cellulose.
C. S. F. And the vegetable fiber pulp itself without adding fine fibrillated cellulose to 300 ml C.I.
S. F. If a clearing paper is manufactured with the stock that has been beaten up to the same amount, the clarity of the clearing is about the same, but in the former case, it is possible to use vegetable fiber pulp in a state where the beatening has not progressed so much. Physical strength, printability,
It is considered that the properties of the paper, such as texture, are improved.

On the other hand, the beating degree of the plant fiber pulp itself, that is, the freeness is 300 ml C.I. S. F. To the extent that the fine fibrillated cellulose is added to the mixture, the freeness of the whole mixture is 200 ml C.I. S. F. It can be reduced to a certain degree. Therefore, 200 ml of C.I. S. F. And the plant fiber pulp itself without adding fine fibrillation, 300 ml C.I. S. F. It is considered that if the transparent paper is manufactured with the stock material beaten up to the above, in the case of the former, the transparent paper with the improved clearness of the transparent paper can be obtained while the properties of the paper are the same.

[0033]

The present invention will be described in detail with reference to the following examples, but the present invention is not limited thereto. All parts by weight are absolute dry parts.

Example 1 1 part by weight of fine fibrillated cellulose (number average fiber length 0.13 mm, water retention value 440%) as pulp used, NB
30 parts by weight of KP and 69 parts by weight of LBKP are mixed, and the mixture is refined with a refiner to a freeness of 300 ml C.I. S. After beating to F, 1.3 parts by weight of rosin sizing agent (trade name "SPN700", manufactured by Arakawa Hayashi Chemical Co., Ltd.) and starch (trade name "Amicol", manufactured by Nitto Chemical Co., Ltd.) were used. A paper stock was prepared by adding 5 parts by weight and 5.5 parts by weight of a fixing agent (sulfuric acid band), and a paper was made with a Fourdrinier paper machine at a basis weight of 110 g / m ² (converted to absolute dry weight).

Character type made of epoxy resin (a bank mark is drawn in a circle: mark width 1.5 mm, circle diameter 3)
(0 mm) was used as the upper net of the dandy roll, and pressed against the web on the paper net to show through. Then, polyvinyl alcohol was coated with a size press for the purpose of improving the surface strength, and thereafter dried in a usual manner to produce a clear paper.

Example 2 Freeness of 200 ml C.I. S. F. A see-through paper was manufactured in the same manner as in Example 1 except that beating was performed until.

Example 3 Freeness 400 ml C.I. S. F. A see-through paper was manufactured in the same manner as in Example 1 except that beating was performed until.

Example 4 5 parts by weight of fine fibrillated cellulose, L
A see-through paper was manufactured in the same manner as in Example 1 except that 65 parts by weight of BKP was used.

Example 5 A mixture of 30 parts by weight of NBKP and 69 parts by weight of LBKP was filtered through a refiner to give a freeness of 460 ml C.I. S. F. After beating up to 1.3 parts by weight of rosin sizing agent "SPN700", 0.5 parts by weight of starch "Amicol" and 5.5 parts by weight of fixing agent (sulfuric acid band), and mixed to form fine fibrils. 1 part by weight of cellulose (number average fiber length 0.13 mm, water retention value 440%) was added and mixed to give a freeness of 400 m.
lC. S. F. Prepared the stock. A see-through paper was manufactured in the same manner as in Example 1 using this paper material.

Example 6 90 parts by weight of kenaf bast pulp was drained to 6 with a refiner.
00 ml C.I. S. F. After beating up to 1.3 parts by weight, 1.3 parts by weight of rosin size agent "SPN700" and starch "Amicol"
0.5 parts by weight, 5.5 parts by weight of a fixing agent (sulfuric acid band) are added and mixed, and further 10 parts by weight of fine fibrillated cellulose (number average fiber length 0.13 mm, water retention value 440%) is added and mixed. Freeness 250 ml C.I. S. F. Prepared the stock. A see-through paper was manufactured in the same manner as in Example 1 using this paper material.

Comparative Example 1 A see- through paper was produced in the same manner as in Example 1 except that fine fibrillated cellulose was not used as the pulp and 30 parts by weight of NBKP and 70 parts by weight of LBKP were used.

Comparative Example 2 As the pulp to be used, 30 parts by weight of NBKP and 70 parts by weight of LBKP were used without using fine fibrillated cellulose, and the freeness was 150 ml C.I. S. F. A see-through paper was manufactured in the same manner as in Example 1 except that beating was performed until.

Comparative Example 3 Freeness 450 ml C.I. S. F. A see-through paper was manufactured in the same manner as in Example 1 except that beating was performed until.

Comparative Example 4 Freeness 150 ml C.I. S. F. A see-through paper was manufactured in the same manner as in Example 1 except that beating was performed until.

Comparative Example 5 A see- through paper was produced in the same manner as in Example 1 except that the pulp used was 0.8 parts by weight of fine fibrillated cellulose, 30 parts by weight of NBKP, and 69.2 parts by weight of LBKP.

Comparative Example 6 88 parts by weight of kenaf bast pulp was drained to 6 with a refiner.
00 ml C.I. S. F. After beating up to 1.3 parts by weight, 1.3 parts by weight of rosin size agent "SPN700" and starch "Amicol"
0.5 parts by weight, 5.5 parts by weight of a fixing agent (sulfuric acid band) are added and mixed, and further 12 parts by weight of fine fibrillated cellulose (number average fiber length 0.13 mm, water retention value 440%) are added and mixed. Then the freeness of 190 ml C.I. S. F. Prepared the stock. A see-through paper was manufactured in the same manner as in Example 1 using this paper material.

Tables 1 and 2 show the results of evaluation of various properties of the show-through paper produced in the above-mentioned Examples and Comparative Examples. Table 1 shows the evaluation results of Examples 1 to 5 and Comparative Examples 1 to 5 using wood pulp as the raw material pulp, and Table 2 shows
It is an evaluation result of Example 6 and Comparative Example 6 which used kenaf bast pulp as a raw material pulp. The evaluation was performed by the following method.

Basis weight: Measured by the method specified in JIS P-8124. Density: Measured by the method specified in JIS P-8118. Clearness of see-through: Visual observation was performed and evaluated by a 5-point method. 5
It shows that the points are the most excellent, and practically 3 points or more are required. Physical strength: The following three kinds of strength were measured and evaluated by the 5-point method. Tensile strength: Measured by the method specified in JIS P-8113. Folding endurance: Measured by the method specified in JIS P-8115. Tear strength: Measured by the method specified in JIS P-8116. Printability: Paper was cut into flat sheets and evaluated using an offset printing machine. A five-point method was used to evaluate the suitability for automatic paper feeding, the expansion and contraction of paper, and the waste of paper (which occurs when the surface strength is weak). Texture of paper: Sensory test by hand was evaluated by a 5-point method.

[0049]

As is clear from Table 1, in each of Examples 1 to 5 of the present invention, as compared with Comparative Example, a clear paper having a good balance of physical strength, printability, and clear clarity was obtained. Can be manufactured. Particularly, fine fibrillated cellulose, NBKP and LBKP were mixed at a ratio of 1:30:69 by weight, and the freeness was 300 ml C.I. S. F. In the case of making paper using the above-mentioned stock and making clear (Example 1),
Good results with good balance have been obtained.

On the other hand, in Comparative Example 1, the freeness of the stock was 300 ml C.M. S. F. Even if
Since fine fibrillated cellulose is not added, the clarity of see-through is inferior and the quality of paper is inferior.

In Comparative Example 2, as a result of increasing the beating degree of the paper stock, the clarity of the see-through is improved, but the quality of the paper is deteriorated because fine fibrillated cellulose is not added.

In both Comparative Examples 3 and 4, fine fibrillated cellulose was added, but the freeness was 400 ml.
C. S. F. Higher 450 ml C.I. S. F. With 200 ml C.I. S. F. Lower 150 ml C.I.
S. F. This is the case. In Comparative Example 3 in which the beating degree is low, the clarity of the see-through deteriorates, and in Comparative Example 4 in which the beating degree is too high, the clarity of the see-through is good, but the quality of the paper deteriorates.

Comparative Example 5 is a case in which the amount of fine fibrillated cellulose added was as low as 0.8% by weight, and the effects of clear clarity and quality improvement as paper were not sufficient.

Further, as shown in Table 2, in the case of Example 6 using kenaf bast pulp having a high drainage as the raw material pulp, when 10% by weight of fine fibrillated cellulose was added, the freeness of the mixture was 250 mlC. ． S. F. Next to
While the effect of improving the quality of the transparent paper as paper is recognized, when the fine fibrillated cellulose is added in a large amount of 12% by weight, the freeness of the mixture is 190 ml C.I. S.
F. As a result, the dimensional stability of the obtained transparent paper becomes poor, the printability becomes poor, and the texture also deteriorates.

[0056]

EFFECTS OF THE INVENTION In the production of conventional transparent paper, considering the physical strength, printability, texture, etc. required for the paper, there was a natural limitation in improving the clarity of the transparent paper. On the other hand, according to the present invention, by combining a predetermined amount of fine fibrillated cellulose having a predetermined number average fiber length and water retention value with vegetable fiber pulp, the physical strength required as paper, printability, and texture. It is possible to manufacture a transparent paper which is excellent in the clarity of the transparent while maintaining the above.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuo Sakano 501 Honjuku, Nagaizumi-cho, Sunto-gun, Shizuoka Special paper manufacturing Co., Ltd. Paper Manufacturing Co., Ltd.

Claims (4)

[Claims] 1. Fine fibrillated cellulose 1-1 having a number average fiber length of 0.05 to 0.3 mm and a water retention value of 250% or more.
0% by weight and 90-99% by weight vegetable fiber pulp and a freeness of 200-400 ml C.I. S. F. A method for producing a see-through paper, which comprises making a paper using the above-mentioned paper material and applying the show-through. 2. The stock comprises a mixture of fine fibrillated cellulose and vegetable fiber pulp having a freeness of 200 to 400.
ml C. S. F. The method for producing a transparent paper according to claim 1, wherein the transparent paper is beaten into pieces. 3. The stock is prepared by mixing finely fibrillated cellulose with pre-beaten vegetable fiber pulp to obtain a freeness of the mixture of 200 to 400 ml C.I. S. F. The method for producing a see-through paper according to claim 1, wherein 4. Freeness 450-700 ml C.I. S. F.
4. The method for producing a transparent paper according to claim 3, wherein the plant fiber pulp is mixed with fine fibrillated cellulose.