JP6171329B2 - Imitation paper - Google Patents

Description

  The present invention relates to an imitation paper that does not break through when an oily marker is used.

  It is common to write with oil-based markers on large-format papers, so-called imitation papers, used for drafting and creation of bulletins and announcements of free research at elementary schools. When writing with a marker, if the ink absorbency of the paper is too good, the ink penetrates to the back side of the paper, so-called “back-through” has been a problem.

  Furthermore, when using thick markers, when using erasers, when masking with adhesive tapes, etc., it is possible to ensure surface strength that does not peel even when the paper surface is easily peeled off, and pencil writing properties are good and eraser is good. After erasing, there are no remaining handwriting, low white paper gloss and no reflection.

  In recent years, environmentally friendly products have been desired, and imitation paper containing waste paper has been desired. However, when waste paper is blended, the strength tends to decrease. As a method for preventing the strikethrough, a method of containing synthetic amorphous silica having a specific oil absorption (Patent Document 1) and a method of using microfibrillated cellulose as a raw fiber (Patent Document 2) are disclosed. .

JP 2002-194696 A JP-A-8-232190

  The present invention provides non-coated paper, particularly imitation paper, which does not show through when writing with an oil marker and has high surface strength.

  As a result of diligent research, the present inventors have found that the blending of raw material pulp has a specific value and high content of ash, thereby preventing back-through by an oily marker and improving surface strength. Completed.

  According to the present invention, even when writing using an oil marker, imitation paper having good surface strength can be produced without being exposed. Further, the imitation paper of the present invention has a low white paper glossiness and is not reflected by light such as a fluorescent lamp. Furthermore, even when used paper is blended, the surface strength is kept good and the back-through can be prevented, so there is little impediment to the environment.

The imitation paper of the present invention has a base paper (hereinafter sometimes referred to as “base paper” in the present specification) and at least one clear coating layer on one side or both sides of the base paper. It does not have a pigment coating layer containing a pigment. Here, the clear coating layer (hereinafter sometimes referred to as a size press layer in the present specification) means a coating layer containing an adhesive as a main component and containing no white pigment. The imitation paper of the present invention is mainly used by handwriting with a writing instrument such as an oil marker, ballpoint pen, pencil, etc., but may be used for offset printing, gravure printing, letterpress printing, and the like. Although the basic weight of the imitation paper of this invention exceeds 40 g / m < ² >, although the upper limit of basic weight is not specifically limited, For example, it can be set to 220 g / m < ² >. 60g ^{/ m 2} ~82g ^/ m 2 about is common, in the present invention, is effective even at a basis weight of 70 g / ^{m 2} or less does not strike through.

Base paper [raw pulp]
Examples of the pulp material of the imitation paper produced by the present invention include thermomechanical pulp (TMP), deinked pulp (DIP), waste paper pulp, softwood bleached kraft pulp (NBKP), and hardwood bleached kraft pulp (LBKP). Any material may be used as long as it is used as a papermaking raw material. Among them, thermomechanical pulp (TMP) is contained in an amount of 8% by weight or more based on the total pulp weight. The thermomechanical pulp is preferably contained in an amount of 10% by weight or more. The upper limit is about 20% by weight. Further, waste paper pulp and / or deinked pulp may be contained in an amount of 50% by weight or more, preferably 70% by weight or more.

[Filler]
The filler used in the paper of the present invention is preferably added so that the ash content (product ash content) in the imitation paper is 15% by weight or more based on the absolute dry weight of the paper. There is no particular upper limit on the ash content, but it is preferably 40% by weight or less in consideration of the strength and operability of the paper. In general, the ash content indicates the amount of inorganic substances contained in the paper, and thus basically reflects the amount of filler contained in the paper. The ash content of paper is composed of those derived from fresh fillers added to the stock and those brought in by pulp raw materials such as DIP (waste paper pulp, deinked pulp). The amount of ash brought in by DIP is relatively high in calcium carbonate, but inorganic components other than calcium carbonate are also included. The ratio of calcium carbonate to other inorganic components depends on the type and collection of used paper such as used newspaper and magazine used paper. It depends on the situation.
In the present invention, the ash content is measured by a method in which the combustion temperature is set to 525 ± 25 ° C. in accordance with the ash test method for paper and paperboard specified in JIS P 8251.

  Examples of fillers added to the base paper include calcium carbonate such as heavy calcium carbonate and light calcium carbonate, titanium oxide, clay, silica, talc, kaolin, calcined kaolin, deramikaolin, magnesium carbonate, barium carbonate, zinc oxide, and oxidation. Inorganic fillers such as silicon, amorphous silica, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, titanium oxide, bentonite; urea-formalin resin, polystyrene resin, melamine resin, phenol resin, fine hollow particles, etc. These organic fillers can be used alone or in appropriate combination of two or more. In addition, recycled fillers made from papermaking sludge, deinking floss, etc. can also be used.

  In particular, in the present invention, it is preferable to use calcium carbonate as a filler because it is inexpensive and excellent in optical properties, and more preferably rosetta type light calcium carbonate. A composite filler such as a calcium carbonate-silica composite (for example, a light calcium carbonate-silica composite described in JP2003-212539A or JP2005-219945A) can also be used. In acidic papermaking, a filler obtained by removing acid-soluble ones from the filler used in the neutral papermaking is used, and used alone or in appropriate combination of two or more.

[Other additives]
In the present invention, a known papermaking additive can be used for internal addition. The papermaking chemicals are not particularly limited, and various chemicals can be used alone or in combination. For example, retention agent, drainage improver, coagulant, sulfate band, bentonite, silica, sizing agent, dry paper strength agent, wet paper strength agent, bulking agent, filler, dye, fluorescent whitening agent, pH adjuster, Papermaking chemicals such as an antifoaming agent, an ultraviolet ray preventing agent, a fading preventing agent, a pitch control agent, and a slime control agent can be used. Among them, it is particularly preferable to add a retention agent as a papermaking chemical because it can greatly enjoy the effect of the present invention that it can be mixed with the paper stock in a short time. In addition to the retention agent, those that can be suitably used as the papermaking chemicals of the present invention include polyacrylamide polymers, polyvinyl alcohol polymers, cationic starch, various modified starches, urea / formalin resins, melamine / formalin resins Internally added dry paper strength enhancer such as polyamide polyamine epichlorohydrin resin Internal wet paper strength enhancer; Rosin sizing agent, AKD sizing agent, ASA sizing agent, petroleum sizing agent, neutral rosin An internal sizing agent such as a sizing agent;

  These auxiliaries may be added to the paper slurry in advance after being added to the filler slurry of the present invention, or may be applied to the paper machine separately from the filler slurry of the present invention.

[Paper making method and machine]
The stock mixed with the papermaking chemical as described above is sent to the head box, and is jetted onto the wire from the head box to make paper. The present invention can be applied to various paper machines and paper making methods. As the paper machine, for example, a long paper machine, a twin wire paper machine, a gap former paper machine, an on-top former paper machine, a Yankee paper machine, and the like can be used as appropriate.

  The papermaking system of the present invention is not particularly limited and may be neutral paper or acidic paper. However, when the paper of the present invention contains a relatively large amount of calcium carbonate, neutral paper is preferable. Specifically, in the present invention, the paper surface pH is preferably 6.0 to 9.0, and more preferably 6.8 to 8.0. The paper making speed is not particularly limited.

[Base weight of base paper]
Although the basic weight of the base paper of this invention is not specifically limited, It is preferable to exceed 41 g / m < ² >. The upper limit of the basis weight of the base paper is not particularly limited, but can be, for example, 220 g / m ² . Furthermore, in the present invention, various surface treatments can be applied to the stencil paper.

Clear coating In the present invention, when a surface treatment agent is applied to the surface of a base paper, for example, a surface coating apparatus installed between a pre-dryer and an after-dryer can be used. As the coating apparatus, a commonly used one can be used, and in a paper machine for printing paper, a film transfer type size press such as a gate roll size press is generally used, and can be preferably used in the present invention. .

  The imitation paper of the present invention may have a clear (transparent) coating layer by applying a clear coating solution containing a starch-based polymer on one side or both sides of a base paper. In the present invention, clear coating, for example, using a coater (coating machine) such as a gate roll coater, rod metering size press, curtain coater, spray coater, etc. This means that a coating solution (surface treatment solution) is applied (size press) on a base paper.

  Examples of the starch polymer of the present invention include those obtained by modifying, modifying, and processing starch. Specifically, for example, modified starch, oxidized starch, oxidized acetylated starch, hydroxyethylated starch (HES), Examples thereof include phosphate ester starch, esterified starch, and dextrin.

  Various types of water-soluble polymers can be used in addition to the above-described starch-based polymer compound as the type of surface coating agent to be applied by clear coating. Examples of the water-soluble polymer substance include starches such as raw starch, cationized starch, enzyme-modified starch, aldehyde-modified starch, hydroxypropylated starch, carboxymethylcellulose, hydroxyethylcellulose, methylcellulose, etc. Cellulose derivatives; modified alcohols such as polyvinyl alcohol and carboxyl-modified polyvinyl alcohol; styrene butadiene copolymers, polyvinyl acetate, vinyl chloride-vinyl acetate copolymers, polyvinyl chloride, polyvinylidene chloride, polyacrylic acid esters, polyacrylamide, etc. Can be used as appropriate. In addition to the above water-soluble polymer substances, general surface sizing agents such as styrene acrylic acid, styrene maleic acid, olefin compounds, alkyl (meth) acrylate compounds, etc., are also used to impart water absorption resistance to paper. In the case of neutral papermaking, it is preferable to apply a sizing agent whose ionicity is cationic.

The amount of clear coating is preferably 1.0 g / m ² or more, more preferably 2.0 g / m ² or more in terms of solid content on one side. If it is less than 1.0 g / m ² , the strength is not exhibited. The upper limit is not particularly limited, but if the coating amount is increased, it is necessary to lower the basic weight of the base paper before clear coating, which decreases the tensile strength and tear strength before clear coating, and makes it easier for paper breaks to occur. Generally, 6.0 g / m ² or less is preferable.

  In this invention, as needed, various adjuvants mix | blended with normal clear coatings, such as a dispersing agent, a thickener, a water retention agent, an antifoamer, a water-resistant agent, and a coloring agent, can be used suitably.

  In the present invention, the base paper can be pre-smoothed by performing pre-calendar processing on the base paper before coating using an online soft calendar, online chilled calendar, or the like.

  In the present invention, the method for drying the wet coating layer is not limited, and various methods such as a steam superheated cylinder, a heated hot air air dryer, a gas heater dryer, an electric heater dryer, and an infrared heater dryer may be used alone or in combination. it can.

  In the present invention, the surface of the imitation paper can be calendered after clear coating, but the type and treatment conditions of the calender are not particularly limited, and a normal calender made of metal roll, soft nip calender, high temperature soft A public apparatus such as a nip calender may be appropriately selected, and the conditions may be set within the controllable range of these apparatuses according to the quality target value.

  Examples of the present invention will be specifically described below in comparison with comparative examples, but the present invention is not limited to these examples. In the description, “%” and “part” indicate “weight percent” and “part by weight” unless otherwise specified. Moreover, about the material addition rate, when there is no designation | designated in particular, the addition rate of solid content is shown.

[Quality evaluation method]
The paper quality of the imitation paper of the present invention was measured according to the method specified below.
(1) Basis weight: Measured according to JIS P8124.
(2) Product ash content: Measured according to JIS P8251.
(3) Paper thickness: Measured according to JIS P8118.
(4) ISO whiteness: Measured with a color difference meter CMS-35SPX manufactured by Murakami Color Co., Ltd. according to JIS P8148.
(5) ISO opacity: Measured with a color difference meter CMS-35SPX manufactured by Murakami Color Co., Ltd. according to JIS P8149.
(6) Pen writing size: measured according to JAPAN TAPPI NO.12. The larger the value, the better the sizing degree.
(7) Magic stain and stain: Two samples were stacked, and a line was slowly drawn with an oil-based magic to evaluate the presence or absence of magic ink stain and stain on the second sheet. If the magic ink does not stain and stain, it can be judged that the show-through is good.

[Example 1]
As a raw material pulp for papermaking, a slurry of LBKP (freeness 350 ml, CSF) 19% by weight, deinked pulp 71% by weight, bleached thermomechanical pulp 10% by weight, and 0.5% by weight of liquid sulfuric acid band with respect to pulp solids (Solid) After adding 22% by weight of light calcium carbonate as a filler and adding a yield improver with a solid content of 350 ppm to pulp, a basis weight of 61.000 m / min at a paper making speed of 600 m / min using a twin wire type paper machine. Paper is made to become 0 g / m ^2, and the modified starch is applied to both the felt surface and the wire surface by 4.5 g / m ² using an on-machine 2-roll size press, and processed with a machine calendar. Thus, an imitation paper having a basis weight of 65.4 g / m ² was obtained.

[Comparative Example 1]
A simulated paper was obtained in the same manner as in Example 1 except that LBKP (freeness 350 ml, CSF) 29% by weight and deinked pulp 71% by weight were used as the papermaking raw material pulp.

  Table 1 shows the results.

  From the results in Table 1, it can be seen that the imitation paper of Example 1 has no penetration and does not show through.

Claims (3)

The raw material pulp contains 8 to 20 % by weight of thermomechanical pulp with respect to the total pulp weight, and further contains 50% by weight or more of waste paper pulp and / or deinked pulp with respect to the total pulp weight. Imitation paper having an ash content of 15% by weight or more. The imitation paper according to claim 1, characterized in that it contains calcium carbonate as a filler.   The method for producing a dummy paper according to claim 1, wherein calcium carbonate is added as a filler.