JP5096428B2 - Multi-layer oil-resistant paperboard, method for producing the same, and oil-resistant paper container using the same - Google Patents

Description

  The present invention relates to a multi-layer paperboard, in particular, a multi-layer oilproof paperboard for use in a paper container for containing foods having oil content such as fried potatoes, fried chicken, donuts, croquettes, dumplings, and the production method thereof, and The present invention relates to a paper container formed from this multi-layer oilproof paperboard.

  Conventional containers for oily foods such as French fries, deep-fried chicken, donuts, croquettes, and dumplings, in addition to plastic trays, contain plastic trays inside high-grade white paperboard cases. , Case made of white paperboard laminated with resin such as polyethylene on the inside, or case made of white paperboard coated with acrylic resin on the inside with gravure coating machine, etc. are used. There is a problem that the manufacturing cost increases due to an increase in materials and manufacturing processes.

  In response to this problem, a technology relating to white paperboard for foods in which the outer layer has water resistance or water repellency, the middle layer has water absorption, and the inner layer has moisture absorption, oil resistance, and peelability has been disclosed (for example, patents) See reference 1.)

JP-A-1-207498

  However, in the conventional technology exemplified in Patent Document 1, when processing into a container such as a tray or a case, a special adhesive must be used to bond the oil-resistant surface of the inner layer and the water-repellent layer of the outer layer. There is a problem of not becoming.

  Moreover, the oil-proofing agent etc. which were mix | blended with the inner layer flow out to the water used at the time of manufacture of food white paperboard, a loss generate | occur | produces, and the subject which produces the stain | pollution | contamination of the apparatus in a manufacturing process by the outflow.

  Therefore, the present invention does not cause loss of oil resistance during production, does not cause equipment contamination due to oil resistance, has low odor, and does not require the use of a special adhesive when processing into a paper container. An object of the present invention is to provide an oil-resistant paperboard and a method for producing the same. The present invention also provides a paper container suitable for containing foods having oil content such as fried potatoes, deep-fried chicken, donuts, croquettes, dumplings, etc., using this multilayer oil-proof paperboard. Objective.

As a result of intensive studies, the inventors of the present invention have a surface layer of the base paper that is the outer surface of the container and the inner surface of the container that comes into contact with the food in the multi-layer oil-proof paperboard used for the paper container that contains the oily food. The back layer does not contain a sizing agent, only a certain amount of sizing agent is contained in the intermediate layer, a fluororesin-based oil-proofing agent is applied to both sides of the base paper with a size press, and finally water-soluble on both sides The present invention has been completed by finding that the above-mentioned problems can be solved by providing a coating layer containing a binder composed only of a polymer. Specifically, the multi-layer oilproof paperboard according to the present invention is a multi-layer paper-proof paperboard having at least a surface layer, a back layer, and an intermediate layer composed of one or more layers provided between the surface layer and the back layer. Using the base paper as a support, the intermediate layer contains a sizing agent in the range of 0.05 to 0.50 parts by mass in terms of solid content with respect to 100 parts by mass of the intermediate layer raw material pulp, and the surface layer and the back layer are It does not contain a sizing agent, the basis weight of the surface layer and the back layer is 40 to 80 g / m ² , and both sides of the base paper are coated with a fluororesin-based oilproof agent by a size press. A coating layer containing a binder consisting only of a water-soluble polymer is provided thereon. In some cases, the raw slurry for forming the surface layer and the back layer may have the same composition. In this case, since the surface layer and the back layer are substantially the same, for convenience, one layer is the surface layer and the other layer is the other. The layer is the back layer.

  In the multi-layer oil-proof paperboard according to the present invention, the coating layer preferably further contains a pigment. Good printability is obtained.

The method for producing a multi-layer oil-proof paperboard according to the present invention comprises a raw material slurry for a surface layer that does not contain a sizing agent, a raw material slurry for a back layer that does not contain a sizing agent, and a size relative to 100 parts by mass of the raw material pulp. A raw material slurry for an intermediate layer formulated so as to contain an agent in a range of 0.05 to 0.50 parts by mass in terms of solid content, and a surface layer having a basis weight of 40 to 80 g / m ² and a basis weight of A base paper having a thickness of 40 to 80 g / m ² and a single layer or a plurality of intermediate layers provided between the surface layer and the back layer are combined to form a multi-layer base paper, and the base paper A liquid containing a fluororesin-based oilproofing agent is applied to both sides by a size press, and then a coating liquid containing only a water-soluble polymer as a binder is applied to both sides.

  The oil-resistant paper container according to the present invention is characterized by using the multi-layer oil-proof paperboard according to the present invention.

  The aqueous polymer refers to an aqueous dispersion, that is, a resin (emulsion) that can be dispersed in water by adding a dispersant, and the water-soluble polymer refers to a resin that dissolves in water at room temperature or by heating, polyvinyl. It refers to polymers such as alcohol (hereinafter referred to as PVA) and starch.

  Multi-layer oil-resistant paperboard according to the present invention does not cause loss of oil-resistant agent during production, does not cause equipment contamination due to oil-resistant agent, has less odor, and uses a special adhesive when processed into paper containers There is no need to do. The method for producing a multi-layer oilproof paperboard according to the present invention does not cause loss of the oilproofing agent during production, and does not cause equipment contamination due to the oilproofing agent. In addition, the paper container according to the present invention is suitable for containing foods having oil such as fried potato, fried chicken, donut, croquette, and dumplings, etc., using this multi-layer oilproof paperboard.

  Hereinafter, the present invention will be described in detail with reference to embodiments, but the present invention is not construed as being limited to these descriptions. As long as the effect of the present invention is exhibited, the embodiment may be variously modified.

  The multi-layer oil-proof paperboard according to the present embodiment includes a base paper for multi-layer paper having at least a surface layer, a back layer, and an intermediate layer composed of one or more layers provided between the front layer and the back layer as a support. To do. The raw material pulp used to form the surface layer, the back layer, and the intermediate layer is a pulp made of wood, bast, scab, etc., whose strength is easily improved by beating. In the present invention, wood pulp is particularly preferable because it is easily available. Specific examples of wood pulp include softwood bleached kraft pulp (N-BKP), softwood unbleached kraft pulp (N-UKP), hardwood bleached kraft pulp (L-BKP), and hardwood unbleached kraft pulp (L-UKP). There is.

Here, in order to obtain the desired effect, the surface layer and the backing layer without blending a sizing agent, basis weight, respectively surface and back layer 40 and 80 g / ^{m 2,} more preferably 40~70g / ^{m 2} , further preferably 40 to 60 g / ^{m 2.}

  When a sizing agent is blended in the surface layer and the back layer, when a liquid containing a fluororesin-based oil proofing agent is applied by a size press, the permeation becomes non-uniform and oil resistance becomes difficult to express.

When the basis weight of the surface layer and the back layer is less than 40 g / m ² , it is difficult to obtain predetermined oil resistance. On the other hand, if it exceeds 80 g / m ² , it is difficult to obtain the effects of the present invention because the basis weight of the intermediate layer must be reduced in order to obtain a predetermined product basis weight. In addition, the basic weight of a surface layer and a back layer does not necessarily need to be the same amount, and either one may be increased. The basis weight of the intermediate layer is 40 g / m ² or more, more preferably 45 g / m ² or more, and still more preferably 50 g / m ² or more.

  Moreover, it is preferable to mix | blend an intermediate | middle layer so that a size agent may be contained in 0.05-0.50 mass part in conversion of solid content with respect to 100 mass parts of intermediate | middle layer raw material pulp. More preferably, it is 0.05-0.45 mass part, More preferably, it is 0.05-0.40 mass part. When the content of the sizing agent is less than 0.05 parts by mass, the size effect of the sizing agent is small and the effect on water resistance is small. On the other hand, even if the content of the sizing agent exceeds 0.50 parts by mass, the effect for improving the water resistance is poor and the cost is large. In addition, as a sizing agent, if it is an acidic or neutral sizing agent, a well-known thing can be used.

  Each layer of pulp slurry blended as described above is made with a paper machine to form a base paper. A paper making machine may be used. In the pulp slurry of the base paper, one or more various additives such as conventionally known fillers, binders, sizing agents, fixing agents, yield improvers, paper strength enhancers and the like may be used as necessary.

  Oil resistance is imparted by applying a liquid containing a fluororesin-based oil resistant agent on both sides of the base paper formed by the above-described method using an on-machine size press. In addition, since the surface layer and the back layer are substantially the same if the surface layer and the back layer are formed in the same composition, for convenience, one layer is set as the surface layer and the other layer is set as the back layer. Any known oil resistance agent can be used as long as it is a fluororesin oil resistance agent. A water-soluble polymer such as PVA or starch can be used for the liquid applied by the size press in order to impart surface strength. In addition, isopropyl alcohol can be used as a penetrant.

  After performing size press treatment with a liquid containing a fluororesin-based oilproofing agent, a coating liquid containing only a water-soluble polymer as a binder is applied to both sides using a coating machine such as a rod, air knife, or blade method. Apply. In this way, the surface of the base paper is size-pressed with a fluororesin-based oilproofing agent, and a coating layer containing a binder composed of only a water-soluble polymer is further provided thereon. In general, an adhesive used when processing a paper container is mainly composed of a water-based polymer or a water-soluble polymer. In the multi-layer oil-proof paperboard according to the present invention, the coating layer is provided in advance by applying a coating liquid containing a water-soluble polymer. The compatibility with the adhesive is improved and the adhesiveness is improved. Therefore, it is not necessary to use a special adhesive to obtain a strong adhesive force.

  Further, since the water-soluble polymer has less residual monomer and no dispersant as compared with the aqueous dispersion of the aqueous polymer, a multi-layered oil-resistant paperboard with less odor can be obtained.

  The coating layer preferably further contains a pigment. More preferably, a pigment is contained in the coating layer provided on the surface layer side. Since the surface layer which is the outer surface of the container is often printed, if a coating liquid containing only a water-soluble polymer as a main component is applied as a pigment and a binder, better printability can be obtained. it can.

  Examples of the drying method after coating include hot air drying, infrared drying, and drum drying, but are not particularly limited in the present invention.

  Since the multi-layered oil-resistant paperboard according to the present invention has been given oil resistance on both sides by a size press, an oil-resistant paper container may be formed with either side as an inner layer in contact with food.

  Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the examples, “parts” and “%” indicate “parts by mass” and “mass%” unless otherwise specified.

Example 1
(Raw material slurry)
After blending 20 parts by weight of softwood bleached kraft pulp (N-BKP) and 80 parts by weight of hardwood bleached kraft pulp (L-BKP) for the surface layer and the back layer, the Canadian Standard Freeness (CSF) by a beating machine The beating process was carried out to 500 ml. Added to 1 part by mass of 100 parts by mass of this raw material pulp, so as to contain 1 part by mass of a sulfuric acid band and 1 part by mass of a paper strength enhancer (Neotac 40T, cationic starch, manufactured by Nippon Shokuhin Kako Co., Ltd.) A slurry was prepared. Next, 20 parts by weight of softwood bleached kraft pulp and 80 parts by weight of hardwood bleached kraft pulp were blended for the intermediate layer, and then beaten to a Canadian standard freeness of 500 ml by a beating machine. 0.08 parts by mass of sizing agent (AL1200, neutral rosin sizing agent, manufactured by Seiko PMC Co., Ltd.), 1 part by mass of sulfuric acid band, and paper strength increase in terms of solid content with respect to 100 parts by mass of the raw material pulp for the intermediate layer A raw material slurry was prepared by adding 1 part by weight of an agent (Neotac 40T, cationic starch, manufactured by Nippon Food Chemical Co., Ltd.).
(Base paper)
Next, using these raw material slurries, the surface layer, the intermediate layer (1), the intermediate layer (2), the intermediate layer (3), and the back layer were combined using a circular net type five-layer papermaking machine. The basis weight of 45 g / m ² , the basis weight of the intermediate layer (1) is 44 g / m ² , the basis weight of the intermediate layer (2) is 50 g / m ² , and the basis weight of the intermediate layer (3) is 44 g / m ^2. A base paper having a basis weight of the back layer of 45 g / m ² was obtained.
(Size press)
On this base paper, using an on-machine size press, in water, PVA (PVA-117K, manufactured by Kuraray Co., Ltd.) 0.5% by mass, oil-resistant agent (AGE-060, fluororesin oil-resistant) The liquid which mix | blended 1.5 mass% (Asahi Glass Co., Ltd. agent) was apply | coated dry mass 1.0g / m < ² > in total of both surfaces.
(Coating layer)
Subsequently, using an air knife type coating machine, prescription A: “3.0% by mass of starch (MS-3800, oxidized starch, manufactured by Nippon Shokuhin Kako Co., Ltd.)” was applied to the surface layer and the back layer 0 times each. It was coated with 0.5 g / m ² (dry mass) to obtain a multi-layer oil-proof paperboard having a basis weight of 230 g / m ² .

(Example 2)
The basis weight of the intermediate layer (2) was changed to 40.5 g / m ^2, and the liquid to be applied to the surface layer using an air knife type coating machine was formulated B (solid content concentration 29.0% by mass). ): “Precipitated calcium carbonate (Brilliant-15, manufactured by Shiraishi Kogyo Co., Ltd.) 70 parts by mass, light calcium carbonate (TP-123, manufactured by Okutama Kogyo Co., Ltd.) 30 parts by mass, starch (MS-4600, esterified starch, Japan Except for changing the coating amount (dry mass) to 10 g / m ² by changing to “10 parts by mass of Food Chemical Industries, Ltd.” and 13.5 parts by mass of PVA (PVA-117K, manufactured by Kuraray Co., Ltd.). In the same manner as in No. 1, a multilayer oil-proof paperboard having a basis weight of 230 g / m ² was obtained.

(Example 3)
The basis weight of each layer of the base paper, the basis weight of the surface layer is 75 g / m ² , and the basis weight of the intermediate layer (1) is 39 g / m ^2.
The basis weight of the intermediate layer (2) was 0 g / m ² , the basis weight of the intermediate layer (3) was 39 g / m ² , and the basis weight of the back layer was 75 g / m ^2. A multilayer oil-resistant paperboard having a basis weight of 230 g / m ² was obtained.

Example 4
A multilayer oil-proof paperboard having a basis weight of 230 g / m ² was obtained in the same manner as in Example 1 except that the sizing agent content in the intermediate layer raw material slurry was 0.40 parts by mass.

(Comparative Example 1)
A multilayer oil-resistant paperboard having a basis weight of 230 g / m ² was obtained in the same manner as in Example 1 except that the sizing agent content in the surface layer and back layer raw material slurry was 0.08 parts by mass.

(Comparative Example 2)
A multilayer oil-resistant paperboard having a basis weight of 230 g / m ² was obtained in the same manner as in Example 1 except that the content of the sizing agent in the intermediate layer raw material slurry was 0.02 parts by mass.

(Comparative Example 3)
The basis weight of each layer of the base paper, the basis weight of the surface layer is 95 g / m ² , and the basis weight of the intermediate layer (1) is 19 g / m ^2.
The basis weight of the intermediate layer (2) was 0 g / m ² , the basis weight of the intermediate layer (3) was 19 g / m ² , and the basis weight of the back layer was 95 g / m ^2. A multilayer oil-resistant paperboard having a basis weight of 230 g / m ² was obtained.

(Comparative Example 4)
The basis weight of each layer of the base paper, the surface layer having a basis weight of ^{25g / m 2, 59g / m} 2 basis weight of the intermediate layer (1), 60 g / ^{m 2} basis weight of the intermediate layer (2), an intermediate layer ( 59 g / ^{m 2} basis weight of 3), except that the basis weight of the backing layer was 25 g / ^{m 2} in the same manner as in example 1, basis weight was obtained a multilayer paper making oil paperboard 230 g / ^{m 2.}

(Comparative Example 5)
The liquid applied to the surface layer was formulated C (solid concentration 40.0% by mass): “70 parts by mass of precipitated calcium carbonate (Brilliant-15, manufactured by Shiroishi Kogyo Co., Ltd.), light calcium carbonate (TP-123, Okutama Kogyo). Co., Ltd.) 30 parts by mass, starch (MS-3800, oxidized starch, Nippon Food Chemicals Co., Ltd.) 3 parts by mass, styrene-butadiene resin latex (L-1432, Asahi Kasei Co., Ltd.) 26 parts by mass. Otherwise in the same manner as in Example 2, a multilayer oil-proof paperboard having a basis weight of 230 g / m ² was obtained.

(Comparative Example 6)
The liquid applied to the surface layer was formulated D (solid concentration 40.0% by mass): “70 parts by mass of precipitated calcium carbonate (Brilliant-15, manufactured by Shiroishi Kogyo Co., Ltd.), light calcium carbonate (TP-123, Okutama Kogyo) ) 30 parts by weight Ltd., styrene - butadiene resin latex (L-1432, except for changing the Asahi Kasei Co., Ltd.) 28 parts by weight "in the same manner as in example 2, the multilayer Extract the basis weight of 230 g / ^{m 2} An oil-resistant paperboard was obtained.

(Comparative Example 7)
A multi-layer oil-proof paperboard having a basis weight of 229 g / m ² is obtained in the same manner as in Example 1 except that the starch solution is not applied to the surface layer and the back layer after the size press by an air knife type coating machine. Obtained.

(Evaluation of salad oil resistance)
After dripping commercially available salad oil on the back surface of the sample, the penetration state of the salad oil under a temperature condition of 60 ° C. was evaluated.
○: Penetration is not seen even after 6 hours and can be used.
Δ: Penetration is not seen even after 1 hour and can be used practically.
X: Penetration was observed within 30 minutes, and not practical.

(Adhesive evaluation)
The front and back surfaces were bonded using a paper box processing adhesive (AV-650, manufactured by Niei Kaiko Co., Ltd.), and the adhesive force and peeled state were evaluated.
A: Adhesive strength equivalent to that of general multilayer paperboard, breakage reaches the paper layer, and can be used practically.
(Triangle | delta): Adhesive force is a little inferior to common multilayer paperboard, and destruction does not reach to a paper layer, but can be used practically.
X: Not bonded and not practical.

(Evaluation of water resistance)
In accordance with JIS P 8122: 2004 “Paper and paperboard—Sizing degree test method—Steecht method”, the Steecht sizing degree (water resistance) was measured.
○: Withstands practical use in 60 seconds or more.
Δ: 10 seconds or more and less than 60 seconds, withstanding practical use.
X: Less than 10 seconds, practically unbearable

(Sensory evaluation of odor)
The presence or absence of odors from the samples was evaluated by randomly selected people (15 people).
○: More than half-everyone feels no odor and is practical.
X: Less than half of the people feel odor and cannot withstand practical use.

  The above evaluation results are shown in Table 1. In all of Examples 1 to 4, the oil resistance, adhesiveness and water resistance of the salad oil were good, and no odor was felt. On the other hand, in Comparative Example 1, since the sizing agent was contained in the surface layer and the back layer, the penetration of the size press solution was not uniform and the oil resistance was poor. In Comparative Example 2, since the sizing agent contained in the intermediate layer was small, the water resistance was inferior. In Comparative Example 3, the basis weight of the surface layer and the back layer was large, and the basis weight of the intermediate layer was small, so that the water resistance was inferior. Comparative Example 4 was inferior in oil resistance because the basis weight of the surface layer and the back layer was small. In Comparative Examples 5 and 6, since an aqueous polymer was used as a binder for the liquid applied to the surface layer, an odor was felt. In Comparative Example 7, the adhesiveness was inferior because no starch solution was applied after the size press.

It can be used as an oil-resistant paperboard used for paper containers for storing foods having oil such as french fries, fried chicken, donuts, croquettes, and dumplings, especially for packaging materials that cause problems with odor generation.

Claims (4)

At least a surface layer, a back layer, and a multilayer paper base sheet having an intermediate layer composed of one or more layers provided between the surface layer and the back layer, as a support,
The intermediate layer contains a sizing agent in a range of 0.05 to 0.50 parts by mass in terms of solid content with respect to 100 parts by mass of the intermediate layer raw material pulp, and the surface layer and the back layer do not contain a sizing agent, The basis weight of the surface layer and the back layer is 40 to 80 g / m ² , respectively.
Both sides of the base paper are coated with a fluororesin-based oil proofing agent by a size press, and further provided thereon with a coating layer containing a binder consisting only of a water-soluble polymer. Oil resistant paperboard.   The multilayer oil-proof paperboard according to claim 1, wherein the coating layer further contains a pigment. 0.05 to 0.50 mass in terms of solid content with respect to 100 parts by mass of the raw material slurry for the surface layer not containing the sizing agent, the raw material slurry for the back layer not containing the sizing agent, and 100 parts by mass of the raw material pulp. A raw material slurry for an intermediate layer formulated so as to be contained within a range of parts,
And the surface layer of the basis weight of 40 and 80 g / ^{m 2,} and the back layer having a basis weight of 40 and 80 g / ^{m 2,} and an intermediate layer consisting of one or more layers provided between the surface layer and the backing layer Multi-layered base paper is formed by combining,
After applying a liquid containing a fluororesin-based oil resistance agent on both sides of the base paper with a size press, a coating liquid containing only a water-soluble polymer as a binder is applied to both sides of the liquid. A method for producing multi-layer oil-resistant paperboard.   An oil-resistant paper container comprising the multi-layered oil-resistant paperboard according to claim 1 or 2.