JP7283970B2 - Greaseproof paper and packaging bag - Google Patents

Description

The present invention relates to oil resistant and packaging bags.

BACKGROUND ART Greaseproof paper is widely used as a packaging material for packaging foods such as fried foods, side dishes, and fast foods such as hamburgers in order to prevent oil contained in the foods from oozing out. Greaseproof paper is required to have oil resistance, and is also required to have heat-sealing (heat-sealing) properties because it is used as a packaging bag or the like. Moreover, in recent years, efforts have been made to prevent environmental pollution by reducing the amount of undecomposed resin. Therefore, studies on alternative technologies for laminate films and resin materials are becoming active, and in doing so, there is a demand for easy processing into packaging bags and the like, for example, for general-purpose heat-sealing processing.

Against this background, conventional greaseproof papers are classified as "greaseproof paper in which at least two coating layers are provided on at least one side of a paper support, in which the outermost layer of the coating layer is closer to the paper support than the outermost layer. Contains starch and / or modified starch in at least one layer close to 5 to 95% by weight of the total solid content of the coating layer, and contains 5 to 95% by weight of styrene-butadiene copolymer latex, and the coating A greaseproof paper characterized by a layer coating weight of 1.5 to 20.0 g/m ² has been proposed (see Patent Document 1). In addition, "A coating liquid mainly composed of an acrylic resin emulsion having oil resistance and heat sealability on at least one side of a base material is added with an acrylic resin emulsion that does not have heat sealability but has water repellency, A heat-sealable water-repellent and oil-resistant paper characterized by forming a coating layer by applying and drying the coating liquid has also been proposed (see Patent Document 2). In addition, ``a heat-sealed portion formed from a polymer emulsion is provided on one or both sides of oil- and water-resistant paper, and the basis weight is 20 to 200 g/m ² , the thickness is 25 to 300 μm, and the air permeability is 200 seconds or less. Characteristic heat-sealable oil- and water-resistant paper” has also been proposed (see Patent Document 3).

However, the greaseproof paper of Patent Document 1 does not give sufficient consideration to the heat-sealability, and according to the knowledge of the present inventors, the heat-sealability (adhesion strength) reaches the level generally required. It may end up being something you don't. Further, although the greaseproof paper of Patent Document 2 is considered for heat-sealability, there is a possibility that it will not reach the required level of oil resistance due to the fact that it is being used in a wider range of applications. Furthermore, the oil-resistant paper of Patent Document 3 considers oil resistance and heat sealability in a high temperature range, but does not consider adhesiveness in a low heating temperature range of about 130 ° C. during heat sealing processing. and lacks versatility.

JP 2014-141750 A JP 2015-155582 A Japanese Patent Application Laid-Open No. 2001-254293

The main problem to be solved by the present invention is to provide an oil-resistant paper and a packaging bag which are excellent in heat-sealability in a low-temperature range as well as oil resistance.

Means for solving the above problems are as follows.
(Means according to claim 1)
Greaseproof paper having a first coating layer and a second coating layer on one or both sides of the base paper,
The first coating layer is mainly composed of kaolin and styrene-butadiene copolymer latex,
The second coating layer is mainly composed of a heat-sealable resin, and has a peel strength of 2.00 N/25 mm or more at 130 ° C.
Greaseproof paper characterized by:

(Means according to claim 2)
The resin having heat-sealing properties is an olefin-based resin,
The coating amount of the second coating layer is 2.0 to 5.0 g/m ² ,
Greaseproof paper according to claim 1.

(Means according to claim 3)
The content ratio of the kaolin and the styrene-butadiene copolymer latex is 70:30 to 80:20 on a mass basis.
The greaseproof paper according to claim 1 or 2.

(Means according to claim 4)
The styrene-butadiene copolymer latex has a gel content of 92 to 98% by mass and a butadiene content of 45 to 60% by mass.
Greaseproof paper according to any one of claims 1 to 3.

(Means according to claim 5)
Formed from the greaseproof paper according to any one of claims 1 to 4,
At least the sheet seal portion satisfies the peel strength condition,
A packaging bag characterized by:

According to the present invention, an oil-resistant paper and a packaging bag that are excellent not only in oil resistance but also in heat-sealing properties in a low-temperature region can be obtained.

Next, an embodiment of the invention will be described. Note that this embodiment is an example of the present invention. The scope of the present invention is not limited to the scope of this embodiment. In addition, unless otherwise specified, the blending amount (addition amount) of each material blended in the base paper described below means the mass ratio to the absolute dry mass of the raw material pulp. Further, the content of each material blended in each coating layer means the absolute dry mass ratio of each material to the total mass of each coating layer excluding the solvent, unless otherwise specified.

The greaseproof paper of this embodiment comprises a base paper and a first coating layer and a second coating layer provided on one or both surfaces of the base paper. The base paper used for this greaseproof paper contains raw material pulp as a main component (preferably 50% by mass or more), and is obtained by papermaking a slurry containing raw material pulp.

As the raw material pulp for the base paper, for example, virgin pulp, waste paper pulp, pulp obtained by combining these pulps, and the like can be used. Specifically, as raw material pulp, for example, hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), softwood unbleached kraft pulp (NUKP), hardwood sulfite pulp, softwood Kraft pulp chemically processed using pulp containing wood fibers such as sulfite pulp as the main raw material, and chemically processed non-wood fibers such as kenaf, hemp, straw, and linter pulp, which are fiber raw materials other than wood, as the main raw material kraft pulp, mechanically pulped chips, ground pulp mechanically pulped with chemicals added to wood or chips, or chips are cooked until soft and refined in a refiner, etc. Virgin pulp such as pulped semi-chemical pulp, kraft pulp, semi-chemical pulp, deinked and bleached office quality waste paper including enzyme-bleached pulp, milk carton waste paper, high-quality cut waste paper, coat cut waste paper, fine white One or a plurality of types can be selected and used from various known raw material pulps such as recovered pulp obtained from unprinted waste paper such as white paper, special white paper, medium white paper, and the like.

However, when the greaseproof paper of this embodiment is used as a food packaging material, it is preferable to use only virgin pulp. In addition, when using bleached hardwood kraft pulp or bleached softwood kraft pulp, among these pulps, bleached, especially chlorine-free bleached so-called ECF (Elemental Chlorine Free) pulp and TCF (Total Choline Free) pulp is preferred. ECF pulp is pulp bleached with chlorine dioxide without the use of chlorine. TCF pulp is pulp that has been bleached with ozone or oxygen. The ECF pulp and TCF pulp have oxygen-activated cellulose terminal groups in the fibers that make up the pulp, so they have a high affinity for oil-resistant agents and provide oil-resistant paper with excellent oil resistance. In addition to ECF pulp and TCF pulp, used paper pulp that has been reduced and bleached with FAS (thiourea dioxide) can also be used as raw material pulp.

Additives (internal additives) can be added to the base paper obtained by papermaking from the raw material pulp, if necessary, usually at the stage of papermaking. Examples of additives include fillers, pigments, sizing agents, coagulants, antifoaming agents, aluminum sulfate, retention aids, drainage improvers, dry strength agents, wet strength agents, coloring dyes, and coloring pigments. , waterproof agents, etc. can be used singly or in combination.

Further, in the stage of making the raw material pulp into paper, an oil resistant agent for imparting oil resistance to the raw material pulp and a fixing agent for fixing the oil resistant agent to the raw material pulp can be added internally. As the oil-resistant agent, for example, one using an acrylic resin, a styrene-butadiene-based resin, or one using a fluororesin can be used. Examples of oil-resistant agents using fluororesin include Asahi Glass Co., Ltd. Asahi Guard AG530 and AG710 (Asahi Guard AG is a registered trademark), Sumitomo Chemical Co., Ltd. Sumirez Resin FP-110 (Sumirez Resin) is a registered trademark), Zonyl RP manufactured by DuPont, and Lodyne 2000 manufactured by Ciba Specialty Chemicals (LODYNE is a registered trademark).

On the other hand, as the fixing agent, for example, polyamide resin, polyamine resin, shrimp chlorohydrin resin, cationic urea, cationic polyacrylamide resin, polyethyleneimine resin and the like can be used.

The base paper has a density of 0.75 to 0.87 g/cm ³ (preferably 0.78 to 0.82 g/cm ³ ), smoothness of 60 to 145 seconds (preferably 64 to 85 seconds), transparency. It is preferable that the temperature is 5 to 40 seconds (preferably 11 to 33 seconds) and the Stockigt size degree is 2 to 10 seconds (preferably 3 to 7 seconds). Within the above ranges, from the viewpoint of the surface properties (smoothness) of the base paper, the formation of the first coating layer is favorable, and the formation of the second coating layer is also favorable. As a result, a coating layer having excellent oil resistance and moisture permeability can be formed. In addition, from the viewpoint of the porosity (density, air permeability) and sizing (Steckigt sizing degree) of the base paper, excessive penetration of the first coating layer into the base paper is prevented, and it is close to the surface of the base paper. Retained in position. As a result, even if oil permeates into the coating layer, since oil resistance is imparted near the surface layer of the base paper, it is possible to prevent oil from permeating the base paper and entering the contents. Furthermore, it is not necessary to impart oil resistance to the base paper itself, and it is also economical.

In addition, the measuring method of each said physical property is as follows.
(density)
It conforms to "Paper and paperboard-Testing methods for thickness, density and specific volume" described in JIS-P8118 (2014).

(Smoothness)
It conforms to "Paper and paperboard - smoothness test method by Bekk smoothness tester" described in JIS-P8119 (1998).

(air permeability)
It conforms to "Paper and paperboard-Air permeability and air resistance test method-Gurley method" described in JIS-P8117 (2009) (low pressure method).

(Steckigt size degree)
It conforms to "Paper and paperboard-Sizing degree test method-Stokicht method" described in JIS-P8122 (2004).

The greaseproof paper of this embodiment comprises at least a first coating layer and a second coating layer provided in this order on one or both surfaces of a base paper. That is, the greaseproof paper of this embodiment is a type of coated paper in which two or more coating layers are provided on the surface of the base paper. The first coating layer and the second coating layer can adjust the oil resistance, heat sealability and moisture permeability of the greaseproof paper of the present embodiment within suitable ranges.

The first coating layer contains at least kaolin and styrene-butadiene copolymer latex as main components. Preferably, kaolin and styrene-butadiene copolymer latex are 50% by mass or more based on the sum of components other than the solvent.

Kaolin is a clay mineral used as an internal and external additive (for surface coating). Kaolin can be classified into, for example, fine kaolin, primary kaolin, secondary kaolin, delaminated kaolin, and the like, when classified by particle size and shape. In the present embodiment, it is preferable to use fine kaolin among these. When the first coating layer contains fine kaolin having a small average particle size, the fine kaolin is scattered and laminated in a plane without steric hindrance in the first coating layer. As a result, a trapping effect that inhibits the permeation of food seasonings such as sauces and mayonnaise, as well as the fat content inherent in the food itself, is exhibited, and the oil resistance is improved. Also, the required amount of binder for fine kaolin is low, and pigments can be bonded together with a small content of styrene-butadiene copolymer latex.

The lower limit of the aspect ratio of the kaolin of the present embodiment is preferably 10 or more, more preferably 12 or more. If the aspect ratio of kaolin is less than 10, sufficient oil resistance may not be obtained. Moreover, the heat-sealing resin used in the second coating layer permeates into minute gaps in the first coating layer, resulting in poor formation of the second coating layer and deterioration in heat-sealability and moisture permeability. parts may occur.

On the other hand, the upper limit of the aspect ratio of kaolin is preferably 120 or less, more preferably 50 or less, and particularly preferably 40 or less. If the aspect ratio of kaolin exceeds 120, the kaolin present on the surface of the first coating layer may interfere with each other, causing steric hindrance in which the arrangement is disturbed. As a result, the state of formation of the first coating layer deteriorates, and there is a risk that the oil resistance will decrease. In addition, the poor state of formation of the first coating layer may affect the second coating layer, resulting in the occurrence of portions where the heat-sealing property is deteriorated.

The lower limit of the kaolin content relative to the total solid content of the composition forming the first coating layer is preferably 30.0% by mass or more, more preferably 33.0% by mass or more. On the other hand, the upper limit of the kaolin content is preferably 50.0% by mass or less, more preferably 40.0% by mass or less. When the kaolin content is within the above range, the effect of improving oil resistance can be reliably obtained. Moreover, excessive permeation of the coating liquid when forming the second coating layer can be suppressed, and unevenness on the surface of the second coating layer can be reduced. This reduction in unevenness leads to suppression of partial deterioration in heat sealability and moisture permeability. In addition, the above-mentioned "total solid content" means the total sum of components other than the solvent in the first coating layer.

The styrene-butadiene copolymer latex, which is a component of the first coating layer, is a latex obtained by copolymerizing at least styrene and butadiene. The styrene-butadiene copolymer latex preferably has a lower gel content of 92% by mass or more, more preferably 93% by mass or more, and particularly preferably 94% by mass or more. On the other hand, the upper limit of the gel content is preferably 98% by mass or less, more preferably 97% by mass or less, and particularly preferably 96% by mass or less. By setting the gel content within the above range, the oil resistance can be enhanced, and the adhesion between the first coating layer and the second coating layer at the time of heat sealing can be enhanced.

The lower limit of the butadiene content of the styrene-butadiene copolymer latex is preferably 45% by mass or more, more preferably 46% by mass or more, and particularly preferably 48% by mass or more. On the other hand, the upper limit of the butadiene content is preferably 60% by mass or less, more preferably 55% by mass or less, and particularly preferably 53% by mass or less. By setting the content of butadiene within the above range, the oil resistance can be enhanced, and the adhesion between the first coating layer and the second coating layer during heat sealing can be enhanced.

The lower limit of the content of the styrene-butadiene copolymer latex to the total solid content of the composition constituting the first coating layer is preferably 20.0% by mass or more, more preferably 22.0% by mass or more. If the content of the styrene-butadiene copolymer latex is less than 20.0% by mass, the oil resistance may not be sufficiently improved, and the first coating layer and the second coating layer may be separated during heat sealing. may not provide sufficient adhesion.

On the other hand, the upper limit of the content of the styrene-butadiene copolymer latex with respect to the total solid content of the composition constituting the first coating layer is preferably 65.0% by mass or less, more preferably 63.0% by mass or less. is. If the content of the styrene-butadiene copolymer latex exceeds 65.0% by mass, the particles of the styrene-butadiene copolymer latex will adhere to each other, degrading the releasability and possibly reducing the processability during bag making. There is

The content ratio of kaolin and styrene-butadiene copolymer latex in the first coating layer is preferably 70:30 to 80:20, more preferably 73:27 to 77:23 on a mass basis. When a polyolefin resin is used for the second coating layer, the adhesion between the second coating layer and the first coating layer tends to decrease, but within the above range, the adhesion is improved.

It is more preferable that the above first coating layer contains an antifoaming agent containing mineral oil. In this regard, when the first coating layer contains a styrene-butadiene copolymer latex, especially when the content is 50.0% by mass or more, the coating liquid forming the first coating layer tends to increase in viscosity. be. If the coating liquid increases in viscosity, it becomes difficult to adjust the coating amount to a low level, and there is a possibility that bubbles may be mixed into the coating liquid. When bubbles are mixed in the coating solution, fine pinholes are formed in the first coating layer, causing oil to permeate the base paper. However, when the first coating layer contains an antifoaming agent containing mineral oil, the viscosity of the coating solution is lowered, making defoaming easier. In addition, the interfacial tension of bubbles is lowered, and minute bubbles gather and float, becoming large bubbles that easily burst on the surface of the coating layer, thereby promoting defoaming.

The mineral oil contained in the defoamer preferably contains an isoparaffinic component. Since the interfacial tension of the isoparaffin-based component is smaller than that of the foam film of the foam, it easily permeates and expands into the foam film, causing the foam to burst from its interior.

The lower limit of the isoparaffinic component content in the antifoaming agent is preferably 20.0% by mass or more, more preferably 30.0% by mass or more. On the other hand, the upper limit of the isoparaffinic component content is preferably 50.0% by mass or less, more preferably 40.0% by mass or less. When the content of the isoparaffin-based component is within the above range, the aforementioned effect of penetrating the foam film of the bubbles and bursting the bubbles increases. In addition, the content of the isoparaffinic component is the content of the isoparaffinic component with respect to the total solid content of the antifoaming agent.

The lower limit of the defoaming agent content to the total solid content of the first coating layer is preferably 0.05% by mass or more, more preferably 0.06% by mass or more. On the other hand, the upper limit of the antifoaming agent content is preferably 0.50% by mass or less, more preferably 0.30% by mass or less. When the content of the antifoaming agent is within the above range, a good antifoaming effect can be obtained, and defects such as pinholes are less likely to be generated in the first coating layer.

In addition to the above, the first coating layer of the greaseproof paper of this embodiment may contain additives. Examples of such additives include water-soluble polymers, adhesives, inorganic pigments, organic pigments, sizing agents, viscosity modifiers, coloring dyes, coloring pigments, waterproofing agents, lubricants, etc., alone or in combination. can be used

Next, the second coating layer formed on the above first coating layer will be described.
The main component of the second coating layer is a heat-sealable resin (heat-sealable resin), and preferably the heat-sealable resin is 50% by mass or more based on the sum of the components other than the solvent.

As the heat seal resin, for example, a styrene-acrylic copolymer, a polyolefin resin, or the like can be used. Here, it is preferable to use a polyolefin-based resin as the resin because the amount of resin can be reduced and the heat-sealing property and oil resistance can be exhibited with a small amount of coating.

Examples of polyolefin-based resins include those obtained by dispersing a resin component containing polyethylene, polypropylene, or the like as a main component in water. Compared to styrene-acrylic copolymers, this material has a coating layer that exhibits plasticity even at low temperatures and improves heat-sealing properties. Therefore, it is possible to reduce the resin material used for the greaseproof paper. Furthermore, among polyolefin resins, ethylene acrylic acid is particularly preferable from the viewpoint of lubricity (reduction of coefficient of friction). Therefore, it has good processability in a processing machine during bag making (reduced shavings generated in the coating layer).

The average molecular weight of the above polyolefin emulsion is preferably 30,000 to 40,000 from the viewpoint of heat sealability. Further, the solid content of the polyolefin emulsion is preferably 25% or more from the viewpoint of coating properties, and from the viewpoint of film-forming properties, it is preferable to use those having a particle size of less than 1.0 μm. is preferred.

As described above, the second coating layer of the present embodiment is mainly composed of a heat-sealable resin, and has a peel strength at 130° C. of 2.00 N/25 mm or more, preferably 2.80 N/25 mm or more. It is preferably 3.50 N/25 mm or more. If the peel strength is less than 2.00 N/25 mm, there is a risk of peeling when used as a packaging bag.

The peel strength can be adjusted, for example, by increasing the amount of coating. Moreover, the upper limit of the peel strength is a state where the base paper breaks, and is approximately 4.00 N/25 mm.

In addition to the above, the second coating layer of the greaseproof paper of this embodiment may contain additives. Examples of such additives include water-soluble polymers, adhesives, inorganic pigments, organic pigments, sizing agents, viscosity modifiers, coloring dyes, coloring pigments, waterproofing agents, lubricants, etc., alone or in combination. can be used

The first coating layer can be formed by applying a coating liquid to one or both surfaces of the base paper. Also, the second coating layer can be formed by applying a coating liquid onto the first coating layer.

In the coating of these coating liquids, for example, a two-roll size press coater, a gate roll coater, a blade metering coater, a rod metering coater, a blade coater, an air knife coater, a roll coater, a brush coater, a kiss coater, a squeeze coater, Known coating machines such as curtain coaters, die coaters, bar coaters, rod coaters and gravure coaters can be used. However, from the viewpoint of forming a dense coating layer, it is preferable to use a rod coater.

The coating weight (in terms of solid content) of the first coating layer is preferably 3.0 to 6.0 g/m ² , more preferably 4.0 to 5.5 g/m ² . By setting this range, even if the first coating layer containing kaolin with a high aspect ratio is provided, cracks during bag making can be prevented, and the second coating with a relatively low solid content concentration can be prevented. Excessive penetration can also be prevented when forming a coating layer (paint).

The coating amount (in terms of solid content) of the second coating layer is preferably 2.0 to 5.0 g/m ² , more preferably 2.5 to 4.5 g/m ² . By setting this range, the desired effect can be obtained with a small amount of coating on the first coating layer with a small surface unevenness (because it contains kaolin with a high aspect ratio), so an excessive drying load is applied. The second coating layer can be formed without

The ratio (absolutely dry) of the first coating layer and the second coating layer is preferably 50:50 to 85:15, more preferably 70:30 to 60:40, based on mass. There is a limit to the coating amount of the entire coating layer from the viewpoint of the heat-sealing properties required for bag making, economic efficiency, and environmental friendliness. By increasing the thickness, the heat sealability can be supplemented by the first coating layer, and the oil resistance can also be improved.

The first coating layer is preferably formed using a paint having a solid content concentration of 45.0 to 55.0% and a B type viscosity of 50 to 550 mPa·S. It is more preferable to use a paint having a 0% B-type viscosity of 200 to 450 mPa·S. On the other hand, the second coating layer is preferably formed using a paint having a solid content concentration of 20.0 to 50.0% and a B type viscosity of 50 to 400 mPa S, and a solid content concentration of 25 to 48%. It is more preferable to use a paint having a B-type viscosity of 150 to 350 mPa·S. As described above, by using paints with different solid content concentrations and B-type viscosities between the first coating layer and the second coating layer, the first coating layer (paint) stays on the surface of the base paper. , has the effect of preventing the penetration of the second coating layer (paint) into the first coating layer and the base paper. In addition, the method for measuring the B-type viscosity is as described later.

In the greaseproof paper of this embodiment, the lower limit of the basis weight measured according to JIS-P8124 (2011) is preferably 35.0 g/m ² or more, more preferably 38.0 g/m ² or more. It is preferably 40.0 g/m ² or more, particularly preferably 40.0 g/m 2 or more. On the other hand, the upper limit of the basis weight is preferably 110.0 g/m ² or less, more preferably 75.0 g/m ² or less, and particularly preferably 55.0 g/m ² or less. When the basis weight is within the above range, the suitability for bag-making process is excellent.

The lower limit of the kit value, which is an index of oil resistance, of the greaseproof paper of this embodiment is preferably 8 or more. If the kit value is less than 8, the oil resistance may be considered insufficient.

As used herein, the term “kit value” refers to the oil resistance of flat surfaces and folds measured under the conditions of 23° C. and 50% humidity (JAPAN TAPPI No. 41 Paper and Paperboard-Oil Repellency Test Method-Kit kit value by law). A higher kit value indicates higher oil resistance.

The oil-resistant paper of this embodiment has a moisture permeability test of 100 to 1200 g/m ² ·24 hr as measured in accordance with JIS Z 0208 (test method for moisture permeability of moisture-proof packaging materials), preferably 300 to 1000 g. /m ² ·24 hr is more preferable. When the moisture permeability is within the above range, steam generated by foodstuffs and the like is released appropriately, and water droplets are less likely to accumulate inside. As a result, it is difficult for water droplets to adhere to the food, etc., and by keeping the humidity at an appropriate level, the food, etc. can be prevented from drying out, and the texture of the food can be maintained for a long time.

The greaseproof paper of this embodiment preferably has a dynamic friction coefficient of 0.23 to 0.75, more preferably 0.28 to 0.28, as measured against a stainless steel plate in accordance with JIS P8147 (2010). 40 is more preferred. If the coefficient of dynamic friction of the greaseproof paper is within the above range, there is a possibility that processing defects may occur due to dregs dropping from the coating layer during processing into a packaging bag.

(packaging bag)
A well-known packaging bag can be used as appropriate, but fertilizer bags, grain bags such as rice and wheat, inorganic and organic chemical agent bags, cement bags, various soil bags, salt bags, road painting paint bags, side dishes, A packaging bag for fast food or the like can be given as an example.

Next, the present invention will be described more specifically by way of examples. However, the scope of the present invention is not limited to the scope of the following examples.

(Manufacture of base paper)
First, as the base paper used in Examples 1 to 3, 100% by mass of bleached hardwood kraft pulp (LBKP) was prepared to obtain a pulp slurry. An internal sizing agent, cationized starch, light calcium carbonate, aluminum sulfate, a coagulant, and a retention agent were added to this pulp slurry. The resulting pulp slurry was made into a base paper (basis weight 41.0 g/m ² , density 0.82 g/cm ³ , smoothness 80 seconds, air permeability 15 seconds, smooth paper by using an on-top fourdrinier machine) Human size degree 4 seconds) was obtained.

Next, as a base paper used in Comparative Example 1, 100% by mass of broadleaf bleached kraft pulp (LBKP) was prepared to obtain a pulp slurry. This pulp slurry was internally added with an internal sizing agent, cationic starch, light calcium carbonate, aluminum sulfate, a coagulant, a retention agent, and a fluorine oil-resistant agent. The obtained pulp slurry was made into paper by an on-top fourdrinier machine to obtain an oil-resistant base paper (basis weight: 50.0 g/m ² ).

As the base paper used in Comparative Example 2, commercially available bleached kraft paper was used.

(Manufacture of greaseproof paper)
A first coating layer (coating: solid content concentration 52.0%, B type viscosity 300 mPa·S) and a second coating layer were formed in this order on one side of the base paper with a rod coater, and the basis weight was 49. A greaseproof paper of 0 g/m ² was obtained. The coating amount and composition of the coating layers (the first coating layer and the second coating layer) were as shown in Table 1. The following chemicals were used for the coating layer. The B-type viscosity is the viscosity at 25° C. specified in JIS Z8803-1 (2011).

(1) Kaolin Kaolin (A): Kaofine (manufactured by Shiraishi Calcium Co., Ltd.) aspect ratio 10
Kaolin (B): Varisurf HX (manufactured by Imeryl Mineral Japan Co., Ltd.) aspect ratio 100

(2) Styrene-butadiene copolymer latex SB latex: T2749N (manufactured by JSR Corporation) gel fraction 94%, butadiene content 55%

(3) Defoamer SN Deformer 777 (manufactured by San Nopco Co., Ltd.) isoparaffinic component content 35.0% by mass

(4) Heat seal resin Styrene-acrylic copolymer (resin): Commercially available chemical: Agent A Polyolefin resin (ethylene acrylic acid): Commercially available chemical: Agent B

Each greaseproof paper was tested for oil resistance, moisture permeability, and heat sealability. The test results are shown in Table 2 together with the basis weight of each greaseproof paper. The basis weight measurement method and various test methods were as follows.

(basis weight)
It was measured in accordance with "Paper and paperboard- Basis weight measurement method" described in JIS-P8142 (1998).

(oil resistance)
The test liquids prepared for kit numbers 8 and 12 were dropped on the plane portion and the manually folded portion of each greaseproof paper, and after 15 seconds, the presence or absence of permeation into the greaseproof paper was observed. The evaluation criteria were as follows. The kit number conforms to the oil repellency test (JAPAN TAPPI No. 41).
◯: There are no pinholes on the front surface of the greaseproof paper, and there is no strike-through on the back surface, and the paper is suitable as an oilproof paper.
Δ: There are pinholes on the front surface of the greaseproof paper, and there is no strike-through on the back surface, but it is somewhat difficult to put to practical use.
x: Strike-through occurred on the back surface of the greaseproof paper, and it cannot be used as greaseproof paper.

(Seropic strength)
Seropic evaluation was performed using a transparent adhesive tape (CT405A-18 manufactured by Nichiban). A tape was attached to the surface of the coating layer of the greaseproof paper and pressed back and forth with a rubber roller 20 times.
◯: The coating layer and the base paper are in close contact with each other, and peeling is not observed.
Δ: The coating layer and the base paper are slightly separated, but there is no problem in use.
x: The coating layer and the base paper are separated and cannot be used.
It should be noted that the heat seal strength also tended to decrease with the peeling.

(dynamic friction coefficient)
Friction coefficient: Based on JIS P8147 (2010), the dynamic friction coefficient with respect to a stainless steel plate was measured.

(moisture permeability)
It was measured according to JIS Z 0208 (moisture permeability test method for moisture-proof packaging materials (cup method).

(Heat sealability)
Using a thermal gradient tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.), the sealer pressure is 2 kg / cm, the sealer time is 2 seconds, and the sealing temperature is 100 to 150 ° C. After pasting, the adhesive area is 10 mm × 25 mm, and the width is 25 mm. The strength was measured by T-shaped peeling at 0.5 m/min with a tensile tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.: Strograph ES). The test environment was standard conditions (23±1° C., 50±2% r.h.) based on JISP8111:1998 “Paper, paperboard and pulp—standard conditions for humidity conditioning and testing”.

The greaseproof paper and packaging bag of the present invention can be suitably used as packaging materials for foods and the like.

Claims (5)

Greaseproof paper having a first coating layer and a second coating layer on one or both sides of the base paper,
The first coating layer is mainly composed of kaolin and styrene-butadiene copolymer latex,
The second coating layer is mainly composed of a heat-sealable resin, and has a peel strength of 2.00 N/25 mm or more at 130 ° C.
Greaseproof paper characterized by: The resin having heat-sealing properties is an olefin-based resin,
The coating amount of the second coating layer is 2.0 to 5.0 g/m ² ,
Greaseproof paper according to claim 1. The content ratio of the kaolin and the styrene-butadiene copolymer latex is 70:30 to 80:20 on a mass basis.
The greaseproof paper according to claim 1 or 2. The styrene-butadiene copolymer latex has a gel content of 92 to 98% by mass and a butadiene content of 45 to 60% by mass.
Greaseproof paper according to any one of claims 1 to 3. Formed from the greaseproof paper according to any one of claims 1 to 4,
At least the sheet seal portion satisfies the peel strength condition,
A packaging bag characterized by: