JP2019014984A - Core base paper - Google Patents

Abstract

To provide colored core base paper for cardboard which can satisfy both unconventional aesthetics and a compressive strength.SOLUTION: This invention is directed to colored core base paper for cardboard comprising at least pulp and coloring material. Particularly, the colored core base paper is characterized in that the pulp contains waste paper pulp and the coloring material is a pigment. The colored core base paper may be used to supply colored core base paper for cardboard which satisfies both aesthetics having not been obtained hitherto and a compressive strength required to the core base paper.SELECTED DRAWING: None

Description

  The present invention relates to a core base paper for corrugated cardboard.

  Corrugated cardboard is an industrial basic material used for packaging and transporting various articles because it is lightweight, inexpensive and durable. Generally, corrugated cardboard is manufactured by pasting a core base paper and a liner with a corrugator. Corrugated cardboard is generally required to have high strength due to its use, and in order to increase the strength of the corrugated cardboard case, particularly the core base paper is required to have high compressive strength.

  On the other hand, in recent years, distribution by mail order etc. has become mainstream, and the number of deliveries using cardboard has increased rapidly. In particular, with the diversification of users, there has been a demand for cosmetics that have not been required with conventional cardboard.

  As a method for producing a core base paper for the purpose of improving cosmetics, a technique for applying a pearl pigment to the surface of a liner base paper has been proposed (Patent Document 1).

JP2002-138390

  Conventionally, as a method for producing corrugated cardboard with improved cosmetics, a proposal has been made regarding liner base paper, but since an expensive material is used, the amount of addition is limited, and further improvement in cosmetics has been demanded. In addition, there has been a demand for strength which is a conventional required quality as a conventional cardboard.

  In view of such circumstances, an object of the present invention is to provide a core base paper for corrugated cardboard that is excellent in strength and beauty.

  As a result of diligent studies to solve the above problems, it was found that a core base paper having both strength and beauty can be produced by adding a colored material to the core base paper used when manufacturing corrugated cardboard. Completed the invention.

  Specifically, a core base paper having a high compressive strength can be obtained.

Although not limited to this, this invention includes the following aspects.
(1) Colored core base paper for corrugated cardboard containing at least pulp and a coloring material.
(2) The colored core base paper of (1), wherein the pulp contains waste paper pulp.
(3) The colored core base paper according to (1) or (2), wherein the colorant is a pigment (4) The colored core base paper according to (3), wherein the pigment is a fluorescent pigment (5) ) The colored core base paper according to any one of (1) to (4) above, wherein the basis weight is a multilayer papermaking having a basis weight of 175 g / m ² or less.

  According to the present invention, it is possible to produce a core base paper excellent in strength and beauty.

[Core paper for cardboard]
The present invention relates to a core base paper for corrugated cardboard. In general, corrugated cardboard is manufactured by laminating a core base paper and a liner. The present invention relates to a core base paper among the base papers for cardboard. In general, the core base paper is processed into a corrugated corrugator and liners are attached to the front and back to produce a high-strength corrugated cardboard, but the corrugated cardboard and corrugated core base paper appear on the surface. Single-sided cardboard is also known, and the core base paper of the present invention can be used for any known type of cardboard.

  The core raw paper of the present invention has a layer using a colored color material on at least one layer of the core raw paper.

The basis weight of the corrugating medium in corrugated cardboard of the present invention is not particularly limited but is preferably 80~180g / ^{m 2,} more preferably 83~150g / ^{m 2,} more preferably 85~130g / ^{m 2.} According to the present invention, since the strength of the core base paper can be effectively improved even when the basis weight of the base paper is small, the present invention is applied to the manufacture of the core base paper having a relatively low basis weight. The effects of the invention can be fully enjoyed.

  The core base paper for corrugated board of the present invention can be processed into a corrugated shape (fluted) using a known corrugator. As the corrugation processing, any known processing can be performed. For example, A flute, B flute, C flute, E flute, F flute, G flute can be applied to the core base paper of the present invention. Depending on the case, AAA flute, AAA flute and the like may be applied to the core base paper of the present invention.

  A known corrugator can be used without limitation, but a general corrugator includes a single facer, a double backer, and a cutter. Further, a glue making apparatus for bonding the liner and the core raw paper, and an apparatus for generating heat for dissolving the glue are also used.

  Various liners can be used without particular limitation as the liner to be bonded to the core base paper for corrugated board of the present invention. As the liner, multilayer paperboard is generally used, and mainly used paper pulp and kraft pulp are used as raw materials. Since the liner is required to have strength and weather resistance, a paper strength enhancer such as polyacrylamide or modified starch may be added, or a sizing agent or water repellent may be used to prevent moisture absorption.

The basis weight of the cardboard is not particularly limited, for example, be a 120~450g / ^{m 2,} in another embodiment, may be 150 and 400 / ^{m 2} and 200-30Og / ^{m 2.}

According to the present invention, even if the basis weight of the base paper is low, the compression strength of the core base paper can be increased. Although the basic weight of the base paper of this invention is not specifically limited, 80-175 g / m < ² > is preferable, 80-135 g / m < ² > is more preferable, 85-125 g / m < ² > is further more preferable. According to the present invention, the strength of the core base paper can be effectively improved even when the basis weight of the base paper is 110 g / m ² or less, and even 100 g / m ² or less.

When the basis weight of the base paper is 100 g / m ² or less, it is preferable to add an internal paper strength agent. As the internal paper strength agent, polyacrylamide (PAM) is preferable. The addition amount is preferably 0.1% to 5.0%, more preferably 0.2% to 2.0%, based on the solid content of the paper.

  The core base paper of the present invention may have a clear (transparent) coating layer provided by applying a coating liquid containing a starch-based compound on one side or both sides of the base paper. In the present invention, the starch coating is, for example, a pond type two roll size press, a gate roll coater or rod metering size press which is a film transfer type coating method, a curtain coater or a spray coater which is a non-contact coating method The coating liquid (surface treatment liquid) containing a starch compound is applied on the base paper using a coater (coating machine).

The amount of starch coating is, it is preferably greater, 0.8 g / ^{m 2} or more preferably a solid per side content, 2.0 g / ^{m 2} or more, and more preferably 3.0 g / ^{m 2} or more, 4 It is good also as 0.0 g / m < ² > or more. When the amount is less than 0.8 g / m ² , the effect of the starch-based compound is not sufficiently exhibited and sufficient internal 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 of starch. Therefore, the coating amount of the starch-based compound is preferably 8.0 g / m ² or less per side, and may be 6.0 g / m ² or less.

In the present invention, various auxiliary agents blended in normal starch coating, such as a dispersant, a thickener, a water retention agent, a defoaming agent, a water resistance agent, and a colorant, can be used as necessary.
In the present invention, as a coating machine for applying the starch-based compound to the base paper, for example, a 2-roll size press, a gate roll coater, a rod metering size press, a blade coater, a bar coater, a spray coater, an air knife coater, A curtain coater can be used. In the present invention, the effect can be exhibited even by using a film transfer type coating machine such as a gate roll coater or a rod metering size press.

[Color material]
The coloring material in the present invention may be either a pigment or a dye, or a combination thereof. Any conventional dyes and pigments may be used, and inorganic pigments, organic pigments, white pigments, fluorescent pigments, and the like are used. Examples of specific embodiments of coloring include orange, green, pink, and yellow, but the present invention is not limited to these color systems.

  In the present invention, the fluorescent pigment is characterized in that it has an effect of increasing vividness, and the inclusion of the fluorescent pigment is preferable because a vivid hue without dullness can be obtained. The fluorescent pigment used in the present invention is for coloring, and is a powder that is insoluble or hardly soluble in water, oil, or an organic solvent and exists in a dispersed state. Fluorescent pigments include organic fluorescent pigments and inorganic fluorescent pigments, both of which can be used, but it is preferable to use organic fluorescent pigments from the viewpoint of excellent light resistance and vivid colors. In the present invention, a dye can be added for the purpose of complementary color. The dye has the effect of increasing the texture of the color. As the dye, a direct dye, a basic dye, or the like can be used, but a basic dye is preferably used.

  As the fluorescent pigment, for example, those described in JP2016-074991 and JP2015-232196 can be used. In the present invention, a colored core base paper having a desired color can be obtained by using pigments of various colors alone or in combination and further using dyes of various colors as necessary. Moreover, about a hue, a desired hue can be obtained by adjusting the compounding quantity of the dye and pigment to add suitably.

  In the present invention, it is preferable to contain a fixing agent in order to obtain a clear hue. As the fixing agent, those described in JP2016-074991 and JP2015-232196 can be used. The addition rate is preferably 0.02 to 5.0% by mass based on the total pulp solid content, but can be adjusted as appropriate.

  In the case of the present invention, a sulfuric acid band can be added in order to further enhance the effect of fixing the fluorescent pigment to the pulp fiber. The addition ratio is preferably 0.5 to 2% to pulp, but can be adjusted as appropriate. In addition, the addition amount of a sulfuric acid band here is addition with a solid.

  As a preferred method for producing the colored core base paper of the present invention, a certain amount of fluorescent pigment is continuously added and mixed together with the pulp raw material in the mixing box or machine chest of the pulp raw material adjusting step for supplying the raw material to the paper machine. Alternatively, the fluorescent pigment is added to the pulp raw material by continuously adding and mixing a certain amount of the fluorescent pigment together with the pulp raw material in a static mixer provided in the middle of the pulp raw material piping leading to the mixing box or machine chest. And the dyed pulp raw material is made into paper. When a fixing agent is added, it is added together with the fluorescent pigment. Thus, when mixing with a mixing box or a static mixer, the pulp raw material and the fluorescent pigment are mixed better, and a dyed mixture without unevenness is generated.

  Furthermore, in this invention, a size press process can be provided and a complementary color can be complemented by adding a fluorescent pigment and / or dye to the coating liquid currently apply | coated in the size press. The coating solution may be water alone, or may contain starch-based, polyvinyl alcohol-based, polyacrylamide-based, cellulose-based water-soluble polymers, and styrene / butadiene-based various copolymers (latex). . These are used individually or in mixture of 2 or more types. In the present invention, water or starch is preferred. The addition rate of the fluorescent pigment and / or dye in this case is not particularly limited, but a concentration of about 0.01 to 10% with respect to water is preferable.

  Even when there is a difference between the front and the back of the hue, a fluorescent pigment and / or a dye can be externally added to the surface side where the hue is to be adjusted. The addition rate is preferably 0.1 to 0.4% with respect to water, but can be adjusted as appropriate.

  To adjust the color, measure the hue of the colored core base paper after paper making using an on-line color meter installed after the paper machine dryer part, and depending on the measurement result, send the fluorescent pigment to the mixing box or the machine chest. The amount of addition of can be adjusted. Furthermore, it is possible to adjust the hue with higher accuracy by adjusting the humidity of the product rolled up on the reel part and measuring it with a color difference meter.

  As described above, in the production of the colored core base paper of the present invention, the case where the fluorescent pigment is internally added has been described as a preferred embodiment, but the present invention is not limited to the internal addition, and the fluorescent pigment is externally added. It may be included. The internal addition is preferable because the cut end of the colored paper cut surface can be uniformly dyed. The method of external addition is not particularly limited, for example, a method of applying a coating liquid containing a fluorescent pigment in a size press process, a method of applying a coating liquid containing a fluorescent pigment by providing a separate coating process, etc. Is mentioned. The coating liquid can contain organic or inorganic pigments and additives.

[Creation of core base paper]
The core base paper of the present invention is preferably a multilayer base paper made from a paper stock containing waste paper pulp. In the case of multilayer papermaking, it is preferable that the layer containing the color material is located at least in the front layer or the back layer, and it is more preferable that all the layers of the multilayer papermaking are layers containing the color material.

[Raw material pulp]
As the pulp raw material of the core base paper produced in the present invention, it is preferable to add a lot of waste paper pulp. In the present invention, the proportion of waste paper pulp in the total pulp is preferably 50% by weight or more, more preferably 70% by weight or more, still more preferably 80% by weight or more, and may be 90% by weight or more.

  As waste paper pulp, unprinted waste paper such as corrugated waste paper, bookbinding, printing factory, cutting office, etc. Used paper pulp, high quality paper, high quality coated paper, medium quality paper, medium quality coated paper, reprinted paper, flat plate, letterpress, intaglio printing, electrophotographic method, heat sensitive method, thermal transfer method, pressure sensitive recording method, ink jet recording method, Waste paper printed with carbon paper, etc., water-based, oil-based ink, waste paper written with a pencil, etc., pulp that has been deinked after disintegrating waste paper (hereinafter sometimes referred to as DIP), paper sludge, paper mill wastewater Scum or the like can be used.

  Among waste paper pulp, low-grade waste paper such as magazine waste paper has low strength, but according to the present invention, the effect is exhibited even when these magazine waste papers are blended in an amount of 30% by weight or more. As pulp other than waste paper pulp, ground pulp (GP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), deinked pulp (DIP), softwood kraft pulp (NKP), etc. You can also use what has been.

[Filler]
The filler used in the paper of the present invention is preferably added so that the ash content in the paper is 10% by weight or more, more preferably 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 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, for example, retention agent, freeness improver, coagulant, sulfate band, bentonite, silica, sizing agent, dry paper strength agent, wet paper strength agent, bulking agent, filler, dye, fluorescent whitening agent, pH adjustment Paper-making chemicals such as an agent, 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.

[surface treatment]
In the present invention, the core base paper can be subjected to various surface treatments. For example, the surface treatment may be performed by a calendar.

In the present invention, a lubricant can be applied to the core base paper. As the lubricant, a wax-based lubricant is particularly preferable, and the coating amount is preferably 0.005 g / m ^{2 to} 0.1 g / m ² . In the present invention, the lubricant is preferably a system in which the lubricant is sprayed onto the calendar roll and transferred to the paper when the base paper is passed through the calendar. By doing so, it becomes possible to prevent dirt from adhering to the surface of the calendar roll in addition to the application of the lubricant. As described above, by applying a lubricant, it is possible to more effectively prevent dirt from adhering to the surface of the calendar roll.

  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]
In this example, the paper quality of the core base paper was measured according to the method specified below.

(1) Basis weight It measured according to ISO536.

(2) Compressive strength The compressive strength of the core base paper was measured according to JIS P 8126.

(3) Cosmetics The appearance of the colored cores obtained in Examples and Comparative Examples was visually evaluated in 5 stages according to the following evaluation criteria, and an average value was calculated. In addition, if the evaluation standard is 3.0 points or more, it has a cosmetic property that can be used.
5: Vivid colors and excellent aesthetics.
4: Vivid colors and beauty.
3: Unlike conventional core base paper, it has a beautiful appearance.
2: Although there is some coloring, it is not much different from the conventional core base paper.
1: It has the same aesthetics as a conventional core base paper.

  Table 1 shows the evaluation results of the core base paper evaluated under the above conditions.

[Example 1 (orange)]
After mixing 70 parts of corrugated paper and 30 parts of magazine paper, a pulp slurry was prepared with a double disc refiner so that the Canadian standard freeness (according to JIS P 8121) was 400 cc. In a mixing box, 2.0 mass% of a fixing agent (trade name “Jetfix PA-401” manufactured by Satorita Chemical Co., Ltd.) and a methine-based cationic dye (trade name “TOA”) per pulp dry mass. Basic Yellow G (L) ”manufactured by Toa Kasei Co., Ltd. 0.8% pulp, pink fluorescent pigment (trade name“ SW-117 Pink ”manufactured by Sinroihi Co., Ltd. 5% pulp), and sulfate band (1.5%) The pulp slurry was dyed by continuously adding and mixing. Using the dyed pulp slurry, four-layer paper making was carried out at a paper making speed of 600 m / min using a papermaking machine to obtain a core base paper of 110 g / m ² .

[Example 2 (Green)]
After mixing 70 parts of corrugated paper and 30 parts of magazine paper, a pulp slurry was prepared with a double disc refiner so that the Canadian standard freeness (according to JIS P 8121) was 400 cc. In a mixing box, 2.0 mass% of a fixing agent (trade name “Jetfix PA-401” manufactured by Satorita Chemical Co., Ltd.) and a methine-based cationic dye (trade name “TOA”) per pulp dry mass. Basic Yellow G (L) "0.5% pulp by Toa Kasei Co., Ltd.), fluorescent pigment (trade name" SW-115 Lemon Yellow ", 5% pulp, fluorescent pigment" SW-128Blue ", Shinrohi Co., Ltd. The pulp slurry was dyed by continuously adding and mixing 1% to pulp) and sulfuric acid band (1.5% to pulp). Using the dyed pulp slurry, four-layer paper making was carried out at a paper making speed of 600 m / min using a papermaking machine to obtain a core base paper of 110 g / m ² .

[Example 3 (pink)]
After mixing 70 parts of corrugated paper and 30 parts of magazine paper, a pulp slurry was prepared with a double disc refiner so that the Canadian standard freeness (according to JIS P 8121) was 400 cc. In a mixing box, 2.0 mass% of a fixing agent (trade name “Jetfix PA-401” manufactured by Satorita Chemical Co., Ltd.) and a methine-based cationic dye (trade name “TOA”) per pulp dry mass. Basic Yellow G (L) ”manufactured by Toa Kasei Co., Ltd., 0.01% vs. pulp), fluorescent pigment (trade name“ SW-117 Pink ”manufactured by Sinroihi Co., Ltd., 10% vs. pulp), and sulfuric acid band (1.5 The pulp slurry was dyed by continuous addition and mixing. Using the dyed pulp slurry, four-layer paper making was carried out at a paper making speed of 600 m / min using a papermaking machine to obtain a core base paper of 110 g / m ² .

[Example 4 (yellow)]
After mixing 70 parts of corrugated paper and 30 parts of magazine paper, a pulp slurry was prepared with a double disc refiner so that the Canadian standard freeness (according to JIS P 8121) was 400 cc. In a mixing box, 2.0 mass% of a fixing agent (trade name “Jetfix PA-401” manufactured by Satorita Chemical Co., Ltd.) and a methine-based cationic dye (trade name “TOA”) per pulp dry mass. Basic Yellow G (L) "0.5% pulp by Toa Kasei Co., Ltd.), fluorescent pigment (trade name" SW-115 Lemon Yellow "3% pulp by Shinhiroi Corporation), and sulfuric acid band (1.5% The pulp slurry was dyed by continuously adding and mixing. Using the dyed pulp slurry, four-layer paper making was carried out at a paper making speed of 600 m / min using a papermaking machine to obtain a core base paper of 110 g / m ² .

[Comparative Example 1]
A core base paper was produced in the same manner as in Example 1 except that the fixing agent and the color pigment were not added.

  As is apparent from the results in Table 1, it can be confirmed that the core base paper according to the example is a core base paper having a good cosmetic property without losing strength as compared with the conventional core base paper.

Claims (5)

  Colored core base paper for corrugated cardboard containing at least pulp and a coloring material.   The colored core base paper according to claim 1, wherein the pulp contains waste paper pulp.   The colored core base paper according to claim 1 or 2, wherein the color material is a pigment.   The colored core base paper according to claim 3, wherein the pigment is a fluorescent pigment. The colored core base paper according to claim 1, wherein the paper is a multilayer papermaking having a basis weight of 175 g / m ² or less.