JP2016211089A - Sterilized paper and sterilized packaging - Google Patents

Abstract

An object of the present invention is to improve the easy peel property of sterilized paper. A sterilized paper includes a paper base material and a thermal adhesive layer laminated on one surface of the paper base material. The polyacrylamide resin is included at least on the one surface, and the concentration of the polyacrylamide resin is higher than the center surface on the one surface. [Selection] Figure 1

Description

  The present invention relates to a sterilized paper and a sterilized package.

  It is necessary to use instruments that are sterilized before use for surgery and treatment, and such instruments are stored in a sterilized package and sterilized. As a sterilization method implemented in hospitals, for example, an object to be sterilized such as a scalpel or forceps is sealed in a sterilization package, and then sterilized using a gas sterilization method, high-pressure steam sterilization method, radiation sterilization method, or the like. A method is mentioned. In the gas sterilization method, the package is put into a pressure-resistant container, the inside of the container is decompressed, the air inside the package is discharged, and then the ethylene oxide gas (EOG) or the like is filled in the container and the gas is filled inside the package. Infiltrate and sterilize. In the high-pressure steam sterilization method, the package is exposed to high-temperature steam using an autoclave or the like, and sterilization is performed by repeatedly depressurizing and pressurizing. In the radiation sterilization method, radiation is sterilized. Of these, high-pressure steam sterilization and gas sterilization are often used from the viewpoint of cost and simplicity.

  Further, the sterilized instrument is stored in the sterilized package until it is used for surgery or the like, and is opened and used when used for surgery or treatment. Therefore, sterilization bags are thin leaves such as two rectangular sheets or films (hereinafter referred to as “film”) so that they can be easily opened even if doctors or practitioners use gloves in hospitals. ) Can be peeled off or manufactured using an easy tearing (easy to tear open) film. When opening, a peel-open method that peels two films or a tearing method is used. It is common.

As a technique regarding a sterilization package, the thing of patent document 1-6 is mentioned, for example. Patent Document 1 proposes a sterilized bag paper in which a thermoplastic resin layer is provided on one side of a base paper. Patent Document 2 proposes a sterilized bag paper obtained by applying an acrylic copolymer to a base paper containing aluminate. Patent Document 3 describes a sterilized paper having a thermoplastic resin layer containing a hollow polymer pigment on the surface of a base paper. Patent Document 4 describes a sterilized paper in which a low air permeability base paper of 10 seconds or less is impregnated with an impregnating agent mainly composed of polyvinyl alcohol. In Patent Document 5, a coating layer is provided on at least one side of a base paper, the coating layer is mainly crosslinked polyvinyl alcohol, and the dry weight after coating is 0.1 to 6 g / m ² . Sterile bag paper is listed. Patent Document 6 describes a sterilized paper in which a low air permeability base paper of 20 seconds or less is impregnated with an impregnating agent mainly composed of an acrylic copolymer.

JP 2001-122348 A JP-A-9-290808 JP 2010-196188 A Japanese Patent Laid-Open No. 2001-200493 JP 2004-84131 A JP 2002-173900 A

For peel-open type sterilized packaging that peels and opens the sterilized paper from the sterilized package, the easy peel property of the sterilized paper is improved so that the sterilized medical device is not recontaminated. It is required to suppress the generation of paper dust due to the substrate destruction. Such a requirement is particularly noticeable in medical sites where high cleanliness is required, such as in the operating room and in the front room of the operating room.
An object of the present invention is to improve the easy peel property of sterilized paper.

The present invention has the following configuration.
[1] A paper base material, and a thermal adhesive layer laminated on one surface of the paper base material,
The paper base material is a sterilized paper containing a polyacrylamide resin on at least one of the surfaces and having a concentration of the polyacrylamide resin larger than that on the center surface on the one surface.
[2] The sterilized paper according to [1], wherein the paper base has a basis weight of 30 g / m ² or more.
[3] The thermal adhesive layer contains one or more selected from ethylene- (meth) acrylic acid copolymers, ethylene-vinyl acetate copolymers, acrylic ester polymers, polyethylene, and polybutenes. The sterilized paper according to [1] or [2].
[4] Any one of [1] to [3], wherein the paper base material is manufactured using a pulp having a freeness measured in accordance with JIS P 8121-2: 2012 of 250 mL or more and 700 mL or less. The sterilized paper according to one item.
[5] The sterilized paper according to any one of [1] to [4], wherein the paper base material includes a polyacrylamide resin having a mass average molecular weight of 50,000 to 500,000.
[6] The sterilized paper according to [5], wherein the paper base further includes a polyacrylamide resin having a mass average molecular weight of 2 million to 10 million.
[7] A paper base and a thermal adhesive layer laminated on one surface of the paper base,
The paper base material includes a polyacrylamide resin on at least the one surface;
The sterilized paper whose content of the said polyacrylamide resin in the said paper base material is 1.0-30 mass%.
[8] A sterilized package obtained by thermocompression bonding of the sterilized paper according to any one of [1] to [7] and a wrapping paper, film, or molded container for sterilization.
[9] Peeling strength when the wrapping paper, the film or the sterilized molded container is peeled 180 ° from the sterilized packaging body at a peeling speed of 300 m / min according to JIS P 8113: 2006 is 200 to 1000 gf / 15 mm. The sterilized package according to [8].

  According to the present invention, the easy peel property of sterilized paper can be improved.

It is sectional drawing which shows typically the sterilization paper which concerns on this embodiment.

The sterilized paper according to the present embodiment includes a paper base and a thermal adhesive layer laminated on at least one surface of the paper base. In addition, a coating liquid containing a polyacrylamide resin is applied to at least the surface of the paper base on which the one thermal adhesive layer is present. Thereby, it becomes possible to cause peeling more easily between the paper substrate and the thermal adhesive layer. Therefore, it is possible to improve the easy peel property when the sterilized paper is peeled from the sterilized package.
In addition, since the peeling can be caused between the paper substrate and the thermal adhesive layer in this way, the thermal adhesive layer constituting the sterilized paper is not attached to the adherend side after the sterilized paper is peeled from the adherend. Will remain. For this reason, it can be easily confirmed that the sterilized paper and the adherend were adhered uniformly.

Hereinafter, the sterilized paper of the present invention will be described with reference to the accompanying drawings showing embodiments.
FIG. 1 is a cross-sectional view schematically showing sterilized paper according to the present embodiment.

(Sterilized paper)
The sterilized paper 1 according to this embodiment includes a paper base 2 and a thermal adhesive layer 3 laminated on at least one surface of the paper base 2. The sterilized paper 1 is thermocompression bonded to an adherend such as a wrapping paper, a film, or a sterilized molded container to form a sterilized package. Examples of adherends include polyolefins exemplified by polyethylene and polypropylene, polyesters exemplified by polyethylene terephthalate, etc., polyvinyl chloride, polyvinylidene chloride, ethylene / vinyl acetate copolymer resins, ethylene / acrylic copolymer resins or The film comprised by these laminated bodies etc. or the molded container for sterilization can be mentioned. The sterilization package has a space for accommodating a container such as a medical instrument between the sterilized paper 1 and the adherend that are thermocompression bonded to each other. In the present embodiment, for example, in a state where the contents are contained in a sterilized package, the contents are sterilized by a sterilization method such as autoclave, ethylene oxide gas (EOG) sterilization, and γ-ray sterilization. Then, when using the sterilized container, the sterilized paper 1 is peeled from the adherend and the container is taken out. The thermal adhesive layer 3 may be formed only on one surface of the paper base 2 or may be formed on one surface and the opposite surface.

(Paper substrate)
The paper substrate 2 is obtained by applying a coating liquid containing a polyacrylamide resin (hereinafter also referred to as “undercoat agent”) to at least one surface of a base paper. When the primer is applied to only one side of the base paper, the primer is applied to the side of the base paper on which the thermal adhesive layer 3 is provided. On the other hand, in this embodiment, a primer may be applied to both one side and the opposite side of the base paper.

The base paper is a paper made from a papermaking raw material containing pulp slurry.
Examples of the pulp used for the pulp slurry include wood pulp and non-wood pulp. Examples of the wood pulp include softwood pulp and hardwood pulp, and any of them may be used. Moreover, the cooking method and bleaching method of wood pulp are not particularly limited. Non-wood pulp includes hemp pulp, kenaf pulp, bamboo pulp and the like. These pulps may be used alone or in combination of two or more.
Materials other than pulp fibers, such as rayon fibers, nylon fibers, and other heat-sealing fibers, can be blended in the pulp slurry as auxiliary materials.

The pulp slurry is obtained by beating the pulp in the presence of water.
The pulp beating method and beating apparatus are not particularly limited, but for example, a double disc refiner (DDR) having high beating efficiency is preferably used.
The beating of the pulp can be carried out so that the freeness of the pulp (hereinafter also referred to as “standard freeness”) measured in accordance with JIS P 8121-2: 2012 is 250 mL or more and 700 mL or less, and 250 mL or more and 600 mL or less. It is more preferable that the beating is performed, and it is more preferable that the beating is performed so as to be 300 mL or more and 500 mL. By setting the standard freeness of the pulp to the above lower limit or more, the air permeability of the paper can be improved. Further, by setting the standard freeness of the pulp to the upper limit value or less, it is possible to improve the strength of the paper and contribute to the improvement of the easy peel property.
In general, regarding the relationship between pulp beating and paper strength, it is difficult to obtain paper strength in the state where the beating is not recommended so much, because the entanglement between pulp fibers is weak and there are few points of interfiber bonding (hydrogen bonding). It is thought that the paper strength is improved by refining to some extent. On the other hand, when the beating is promoted, the entanglement between the pulp fibers increases and the points of interfiber bonding increase, so that paper strength is obtained, but the voids of the fibers are reduced, and the air permeability of the base paper is reduced. If the standard freeness of the pulp is within the above range, the paper strength can be sufficiently increased while maintaining the air permeability of the base paper, and thus the paper base material 2, and the easy peel suitability of the sterilized paper 1 is further improved. It becomes possible.

  In the present embodiment, for example, various paper additive chemicals are added to a pulp slurry obtained by beating to prepare a papermaking raw material. Examples of the internal additive include various fixing agents such as a sizing agent, paper strength enhancer, wet paper strength enhancer, sulfate band, and cationized starch. In addition to these, a yield improver, an antifoaming agent, a filler, a colorant and the like can be arbitrarily added to the papermaking raw material as internal additives.

The paper strength enhancer can include one or more selected from, for example, polyacrylamide resin, cationized starch, and polyvinyl alcohol. Among these, by adding a polyacrylamide resin-based paper strength enhancer, the strength of the base paper can be more effectively improved and the easy peel property can be further improved. Moreover, in order to give the paper strength enhancing effect after addition, the mass average molecular weight is preferably 2 million (Mw) or more. In addition, it is preferable that the mass average molecular weight is 10 million (Mw) or less because the viscosity is high and it is difficult to add in operation. In addition, the said mass average molecular weight of polyacrylamide resin is a polyethylene oxide conversion value measured by gel permeation chromatography (GPC). In addition, as the polyacrylamide resin as a paper strength enhancer, for example, an anionic, cationic, amphoteric or nonionic polyacrylic resin can be used, but it is particularly preferable to use an amphoteric polyacrylamide resin.
As the sizing agent, those known as sizing agents can be used, and for example, one or more selected from alkenyl succinic acid, alkyl ketene dimer, rosin and the like can be included. In addition, as the wet paper strength enhancer, those known as wet paper strength enhancers can be used, and for example, one or more selected from epichloro resin and melamine resin can be included.

  In the present embodiment, for example, a base paper can be obtained by paper-making the paper-making raw material thus prepared by a conventional method. In addition, the basic weight of a base paper can be suitably set according to the basic weight of the paper base material 2, and the application quantity of a primer.

The primer includes a polyacrylamide resin.
In the present embodiment, the polyacrylamide resin is a polymer having (meth) acrylamide units. “(Meth) acrylamide” is a general term for acrylamide and methacrylamide. The polyacrylamide resin may have either one of acrylamide units or methacrylamide units, or may have both. Moreover, the polyacrylamide resin may have units other than the (meth) acrylamide unit.

  Examples of the polyacrylamide resin contained in the primer include anionic polyacrylamide resins, cationic polyacrylamide resins, amphoteric polyacrylamide resins, and nonionic polyacrylamide resins. Each of these can be used as a paper strength agent in the field of papermaking, for example, those described in JP-A-2002-317393, JP-A-2004-231901, JP-A-2014-205938, etc. It is done. A polyacrylamide resin may be used individually by 1 type, and may be used in combination of 2 or more type. In view of availability, an anionic polyacrylamide resin is preferable.

  The anionic polyacrylamide resin can contain an anionic functional group such as a carboxy group, a sulfonic acid group, or a phosphoric acid group, or a salt thereof. Examples of such an anionic polyacrylamide resin include a copolymer of (meth) acrylamide and an anionic functional group-containing monomer (such as acrylic acid), and a poly (meth) acrylamide partial hydrolyzate.

  The polyacrylamide resin contained in the primer is preferably one having a mass average molecular weight (Mw) of 50,000 to 500,000, and more preferably 50,000 to 300,000. When the mass average molecular weight of the polyacrylamide resin is within the above range, the effect of suppressing fuzz on the surface of the paper substrate is more excellent. If the mass average molecular weight is not less than the lower limit of the above range, the effect of suppressing fuzz on the surface of the paper substrate 2 when the thermal adhesive layer 3 is peeled is easily obtained. When the mass average molecular weight is not more than the upper limit of the above range, the viscosity is low enough for the undercoat to be applied, and the preparation and application of the undercoat are easy. In addition, the concentration of the polyacrylamide resin in the primer can be increased, and the desired coating amount can be easily obtained. In addition, the said mass average molecular weight of polyacrylamide resin is a polyethylene oxide conversion value measured by gel permeation chromatography (GPC).

The primer typically includes a liquid medium.
The liquid medium is preferably one that dissolves polyacrylamide resin, and examples thereof include water.

The undercoating agent may contain other components than the polyacrylamide resin as needed, as long as the effects of the present invention are not impaired.
Examples of other components include, but are not limited to, starch, modified starch, polyvinyl alcohol, modified polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, gum arabic, diisobutylene / maleic anhydride copolymer Compound salts, water-soluble polymer compounds such as styrene / maleic anhydride copolymer salts, styrene-butadiene copolymer emulsions, acrylate copolymer emulsions, urethane resins, urea resins, styrene-acrylic resin emulsions, ethylene- Examples include aqueous polymer compounds such as acrylic resin emulsions, mold release agents, antifoaming agents, dispersants, wetting agents, colored dyes, colored pigments, white pigments, and the like. Any one of these may be used alone, or two or more may be used in combination.

  The content (concentration) of the polyacrylamide resin in the primer is preferably 50 to 100% by mass and more preferably 80 to 100% by mass with respect to the total solid content (100% by mass) in the primer. If content of polyacrylamide resin is more than the lower limit of the said range, the easy peel suitability of sterilized paper can be made more favorable. The total solid content is the total amount obtained by removing the liquid medium from the primer, and is the total of the polyacrylamide resin and the other components.

The amount of the primer applied to the base paper is set according to the content of the polyacrylamide resin in the primer. The coating amount of the primer on the side of the base paper on which the thermal adhesive layer 3 is provided is preferably 0.05 to ²⁰ g / m ² in terms of the amount of polyacrylamide resin, It is more preferably 15 g / m ² and further preferably 0.2 to 10 g / m ² . If the application amount of the polyacrylamide resin is equal to or greater than the lower limit of the above range, the paper substrate 2 and the thermal adhesive layer 3 are favorably peeled when the sterilized paper is peeled, and the surface of the paper substrate 2 is fuzzy Material destruction is less likely to occur. Moreover, if the application amount of the polyacrylamide resin is less than or equal to the upper limit of the above range, uneven adhesion can be suppressed when heat-sealing sterilized paper. The undercoat can be applied substantially uniformly to the entire surface of the base paper on the side where the thermal adhesive layer 3 is provided. On the other hand, the undercoat may be applied so as to have a predetermined pattern, for example, on the surface of the base paper on which the thermal adhesive layer 3 is provided.

When the primer is applied to the other surface of the base paper opposite to the one surface on which the thermal adhesive layer 3 is provided, the component of the primer layer is not particularly limited. For example, one or more selected from resins such as starch, polyvinyl alcohol, polyacrylamide resin, and styrene-butadiene resin, and pigments such as kaolin, talc, calcium carbonate, and white carbon are applied to the other surface. It can be included in the undercoat layer. In addition, although it does not specifically limit as polyacrylamide resin, For example, the thing similar to what is used for the undercoat apply | coated to the one surface side is employable. In the present embodiment, for example, the primer applied on one side and the primer applied on the other side may be the same as each other or different from each other.
When the primer is applied to the other side of the base paper, the coating amount is not particularly limited, but can be 0.01 to 20 g / m ² in terms of solid content, for example. In the present embodiment, it is preferable that the coating amount is 0.01-5 g / ^{m 2} or less, more preferably 0.01 to 3 g / ^{m 2,} is 0.1-2 g / ^{m 2} More preferably. When the coating amount is not more than the upper limit of the above range, the air permeability of the sterilized paper can be kept good. Further, by adjusting the application amount of the primer on the other side of the base paper in this way, it becomes easy to appropriately control the concentration of the polyacrylamide resin on one side, the center side, and the other side of the base paper. In addition, when apply | coating a primer to each of the one surface and other surface of a base paper, although it does not specifically limit, For example, ratio of the coating amount in one surface and the coating amount in another surface can be set to 3: 7-7: 3. Thereby, it becomes easier to make the concentration of the polyacrylamide resin in the base paper larger than the center face on one side and the other side of the base paper. In addition, from the viewpoint of reducing the manufacturing cost of sterilized paper, a case where a primer is not applied to the other side of the base paper can be adopted as an example of a preferred embodiment.

As described above, the paper base 2 is obtained by applying a primer to at least one surface of a base paper and drying it. The method for applying the primer is not particularly limited, and can be performed using various known wet coating methods. For example, it can be performed using an on-machine size press device of a paper machine, a transfer roll coater (such as a shim sizer or a gate roll coater), a spray device, or the like. In the off-machine, general coating equipment such as blade coater, air knife coater, roll coater, reverse roll coater, shim sizer, gate roll coater, bar coater, curtain coater, slot die coater, gravure coater, and Chanplex coater. It can be applied using a brush coater, a two-roll coater, a bill blade coater, a short dwell coater or the like.
In consideration of operability and productivity, it is preferable that the application and drying of the primer are performed on-machine. Accordingly, the type of paper machine for making the base paper is not particularly limited, such as a long net paper machine, a short net paper machine, a circular net paper machine, etc., but an on-machine coating machine is equipped. Is preferably used.

  Since at least a part of the primer applied to one surface of the base paper soaks into the base paper, the interior of the base paper after application contains polyacrylamide resin as a primer. When only a part of the applied primer has soaked into the base paper, the base coat that has not soaked is dried on one side of the base paper, so that a layer containing a polyacrylamide resin on one side of the base paper ( Hereinafter, it is also referred to as “undercoat layer”). In this case, the obtained sterilized paper 1 has an undercoat layer containing a polyacrylamide resin between the paper base material 2 and the thermal adhesive layer 3 provided on the paper base material 2. On the other hand, an undercoat layer may not be provided on one side of the base paper. Even in this case, since one surface of the base paper and the vicinity thereof are impregnated with polyacrylamide resin as a primer, sterilized paper having excellent easy peelability can be obtained. The presence or absence of the undercoat layer can be confirmed by pyrolysis GCMS (gas chromatograph mass spectrometry) or the like by shaving the surface and middle layer portion of the paper substrate 2 with a razor or the like.

In the present embodiment, for example, a paper base 2 is formed by applying a primer to one surface of a base paper. In this case, since the undercoat gradually soaks into the inside from one side of the base paper, the paper substrate 2 has a configuration in which the concentration of the polyacrylamide resin gradually decreases from one side to the opposite side. For this reason, the density | concentration of the polyacrylamide resin in the paper base material 2 can be made larger than the center surface in one surface of the paper base material 2. FIG. As described above, since one surface of the paper substrate 2 can contain polyacrylamide resin at a high concentration, the paper substrate 2 and the heat provided on one surface of the paper substrate 2 when the sterilized paper 1 is peeled off. It becomes possible to cause good peeling with the adhesive layer 3. Therefore, it becomes possible to improve the easy peel property of sterilized paper.
The density | concentration of the polyacrylamide resin in each area | region in the paper base material 2 can be measured by pyrolysis-GCMS, for example. In the present embodiment, for example, one side and the other side of the paper base material 2 and the divided surface obtained by dividing the paper base material 2 into two layers using a suitable adhesive tape are shaved with a razor or the like. By performing pyrolysis GCMS, it is possible to confirm the concentration of the polyacrylamide resin on the one surface, the opposite surface, and the center surface. Further, in the present embodiment, the central surface of the paper base material 2 is formed, for example, by connecting the midpoints of the average surface of one surface of the paper base material 2 and the average surface of the other surface opposite to the one surface. Point to a plane. The midpoint of the average surface of one surface and the average surface of the other surface refers to the midpoint of the shortest distance of the other surface from the specific point of one surface. Moreover, the average surface of each surface means a surface that passes through the average height of the concave and convex portions when the surface has an uneven shape, and each average surface is It means a surface. In the present embodiment, for example, a paper base 2 can be formed by applying an undercoat containing a polyacrylamide resin to one side and the other side of a base paper. In this case, the paper substrate 2 has a region where the concentration of the polyacrylamide resin gradually decreases from one surface toward the center surface. For this reason, it becomes possible to make the density | concentration of the polyacrylamide resin in the paper base material 2 larger than the center surface in one surface of the paper base material 2. FIG.

In the present embodiment, the content of the polyacrylamide resin in the paper substrate 2 can be set to 1.0 to 30% by mass, for example. Thus, since the paper base material 2 can contain a polyacrylamide resin at a high concentration, the paper base material 2 and a thermal adhesive layer provided on one surface of the paper base material 2 when the sterilized paper 1 is peeled off. It is possible to cause good peeling between the two. For this reason, it becomes possible to improve the easy peel property of sterilized paper. On the other hand, by making the content of the polyacrylamide resin not more than the above upper limit value, it becomes possible to improve the heat sealability of the sterilized paper.
When a polyacrylamide resin is internally added to a paper base material as a paper strength enhancer or the like, it is difficult to produce a paper base material containing a large amount of polyacrylamide resin. As a result of intensive studies, the present inventor can form a paper substrate 2 containing a large amount of polyacrylamide resin by applying a primer containing polyacrylamide resin to at least one surface of the base paper. I found it. In this embodiment, the paper base 2 containing 1.0% by mass or more of polyacrylamide resin is realized by applying the primer containing polyacrylamide resin to at least one surface of the base paper.

The basis weight of the paper substrate 2 is, for example, preferably 30 g / m ² or more, more preferably 40 g / m ² or more, and further preferably 45 g / m ² or more. If the basis weight of the paper substrate 2 is equal to or more than the lower limit, it is easy to obtain a strength that can withstand the peeling of the sterilized paper 1, and the substrate does not easily break during peeling. Although the basis weight of the upper limit of the paper substrate 2 is not particularly limited, but is preferably from the viewpoint of air permeability is 300 g / ^{m 2} or less, more preferably 250 g / ^{m 2,} more preferably 200 g / ^{m 2} or less . The basis weight of the paper substrate 2 and the base paper is measured in accordance with, for example, JIS P 8124: 2011.

Density of the paper substrate 2, for example, is preferably 0.60~1.20g / cm ^3, more preferably 0.70~1.10g / cm ^3. If the density of the paper substrate 2 is equal to or higher than the lower limit, it is easy to obtain a strength that can withstand an easy peel, and the substrate does not easily break during peeling. If the density of the paper substrate 2 is equal to or less than the upper limit value, air permeability can be maintained. The density of the paper base material 2 is obtained by calculation from the measured values of thickness and basis weight, for example, by measuring the thickness in accordance with JIS P 8118: 1998.

  In the present embodiment, for example, a case where a first polyacrylamide resin added as an undercoat and a second polyacrylamide resin added as a paper strength enhancer are both included in a paper base material is a preferred embodiment. As an example. The first polyacrylamide resin and the second polyacrylamide resin may be the same as each other, but are preferably different from each other. In the present embodiment, for example, a first polyacrylamide resin having a mass average molecular weight of 50,000 to 500,000 and a second polyacrylamide resin having a mass average molecular weight of 2 million to 10 million are both contained in a paper substrate. Can be included. Thereby, it becomes possible to more effectively suppress substrate destruction and fluffing in the paper substrate when the sterilized paper is peeled off.

(Thermal adhesive layer)
The thermal adhesive layer 3 is, for example, one or two selected from ethylene- (meth) acrylic acid copolymer, ethylene-vinyl acetate copolymer, acrylic ester polymer, polyethylene, polybutene, and polyethylene-polybutene mixture. The heat adhesive resin containing the above can be included. Among these, it is more preferable that an ethylene-acrylic or ethylene-vinyl acetate copolymer is included as a main component of the heat bonding layer 3.

The heat bonding layer 3 can be formed, for example, by applying a heat sealing agent containing the above heat bonding resin and a liquid medium to one surface of the paper substrate 2 and drying it. Note that, as described above, an undercoat containing polyacrylamide resin is applied to one surface of the paper substrate 2. In the present embodiment, the thermal adhesive layer 3 may be provided on one surface and the opposite surface of the paper substrate 2. In this case, the heat adhesive layer 3 is formed by applying a heat sealant to one side and the opposite side of the paper substrate 2 and drying. At this time, it is preferable that an undercoat containing a polyacrylamide resin is applied to both one side and the opposite side of the paper substrate 2.
The heat sealing agent may be an aqueous heat sealing agent in which the above materials are dissolved or dispersed in water, or may be a solvent heat sealing agent in which the above materials are dissolved in a solvent. Examples of the water-based heat sealant include an ethylene-vinyl acetate copolymer emulsion, an ethylene- (meth) acrylic acid copolymer emulsion, an acrylate polymer emulsion, a polyethylene emulsion, and a polyethylene-polybutene mixture emulsion. . Among these, an ethylene-vinyl acetate copolymer emulsion, an acrylate emulsion, and a polyethylene emulsion exhibit a stable peeling force and increase the burst strength measured according to ISO 2758 without increasing the burst strength. This is preferable because it has a high effect of suppressing the occurrence of inversion.

It does not specifically limit as a coating method of a heat seal agent, It can carry out using various well-known wet coating methods. For example, a method similar to the method of applying the primer is mentioned.
As for the drying equipment, drying by a drying equipment such as an air dryer or an infrared heater that does not come into contact with the coating surface is preferable from the viewpoint of reliably suppressing contamination of the equipment, but a coating surface direct contact method using a cylinder dryer can also be used.

The coating amount of the heat bonding layer 3 (the dry coating amount of the heat sealing agent) is not particularly limited, and is appropriately selected according to the material of the adherend to which the heat bonding layer 3 is bonded and the heat sealing conditions. Preferably it is 0.1-30 g / m < ² >, More preferably, it is 0.3-10 g / m < ² >. If the coating amount of the heat bonding layer 3 is not less than the above lower limit value, a satisfactory heat bonding force can be easily obtained. For example, when thermally bonded as a sterilization bag, the sterilized paper is difficult to peel off. If the coating amount of the thermal bonding layer 3 is equal to or less than the above upper limit value, the paper base material 2 is unlikely to break during easy peel. In addition, the thermal bonding layer 3 is less likely to exhibit the spinnability, and the contained object is less likely to be contaminated.

  In the present embodiment, the sterilized paper 1 has an Oken-type air permeability measured according to JIS P 8121-2: 2012, for example, preferably 700 seconds or less, and more preferably 500 seconds or less. , 300 seconds or less is particularly preferable. Thereby, the air permeability of the sterilized paper 1 can be improved more effectively. On the other hand, the lower limit value of the Oken air permeability is not particularly limited, but may be 5 seconds, for example. The Oken type air permeability of the sterilized paper 1 can be controlled by appropriately selecting, for example, the pulp freeness, the basis weight of the paper base material 2, and the amount of primer applied.

  In this embodiment, the sterilized package obtained by thermocompression bonding of the sterilized paper 1 and the adherend is peel strength when the adherend is peeled 180 ° at a peel rate of 300 m / min according to JIS P 8113: 2006. Is, for example, 200 to 1000 gf / 15 mm. Thereby, the sterilization packaging body excellent in the balance of an easy peel property and a heat seal property is obtained. Further, from the viewpoint of more effectively improving the balance between the easy peel property and the heat seal property, the peel strength is more preferably 250 to 900 gf / 15 mm. The peel strength can be controlled, for example, by appropriately selecting the amount and type of primer applied, the type of thermal adhesive layer, and the like. The adherend is, for example, a wrapping paper, a film, or a molded container for sterilization.

(Function and effect)
In the sterilized paper 1, since the primer which contains polyacrylamide resin is apply | coated to the surface by which the heat bonding layer 3 is provided among the paper base materials 2, it is excellent in easy peel suitability. For example, when the sterilized paper 1 is thermally bonded to an adherend (film) and then peeled off from the adherend, the thermal adhesive layer 3 is easily peeled off from the interface with the paper substrate 2 while adhering to the adherend side. The paper substrate 2 is not easily torn. Further, when the thermal adhesive layer 3 is peeled off, the surface of the paper base 2 is not easily fluffed and the paper piece is hardly peeled off from the surface. Further, since the thermal adhesive layer 3 can be visually recognized on the adherend (film) side, it can be easily confirmed that the adhesive has been adhered uniformly before peeling. Moreover, since the paper base material 2 is hard to tear, when peeling the sterilized paper 1 from a to-be-adhered body by an easy peel system, the whole can be peeled at once. Moreover, since fluffing and peeling of the paper pieces are suppressed, it is possible to prevent the fibers dropped from the fluffy parts and the peeled paper pieces from adhering to the adherend and the object to be accommodated.

  Furthermore, examples of the sterilization method of sterilized paper include several sterilization methods such as autoclave, ethylene oxide gas (EOG) sterilization, and γ-ray sterilization. In particular, EOG sterilization requires gas replacement after sterilization. About the sterilized paper which concerns on this embodiment, air permeability can also be made excellent by the freeness of the pulp used for manufacture of the paper base material 2, and the basic weight of a paper base material. For this reason, it is possible to realize a sterilized paper particularly suitable for EOG sterilization.

Conventionally, it has been difficult to achieve both excellent easy peelability and air permeability with sterilized paper.
According to the present embodiment, as described above, by providing an easy peel property to the sterilized paper, the sterilized paper that can be used in an operating room with a high degree of cleanliness can be provided by suppressing the flaking at the time of peeling. Can do. Further, the air permeability of the sterilized paper can be increased, and the time for replacing the sterilized gas after sterilization with air can be shortened. As described above, the sterilized paper of the present invention is extremely useful in practice and has an excellent balance between easy peel and air permeability.

In addition, when the undercoat containing polyacrylamide resin is applied to the surface of the paper base 2 on which the thermal adhesive layer 3 is laminated, the thermal adhesive layer 3 is peeled from the paper base 2. The reason why it is possible to suppress the destruction of the paper base material 2, the fuzz of the surface, the falling off of the paper piece from the surface, etc. is considered as follows.
Polyacrylamide resin is a hydrogen that acts between pulp fibers by forming a hydrogen bond between the amide group in the molecule and the hydroxyl group in cellulose and hemicellulose molecules, or between the amide group of the polyacrylamide resin itself. Increase the number of bonds. Thereby, the bond of the network of pulp fibers is strengthened, and when the heat seal sheet is peeled from the adherend, it is possible to prevent the pulp fibers from being taken by the heat bonding layer peeled from the paper base material 2. According to the study by the present inventors, the polyacrylamide resin is excellent in the effect of suppressing the above-mentioned substrate destruction and fluffing as compared with other water-soluble polymers such as polyvinyl alcohol and hydrophobized starch. In addition, the polyacrylamide resin has a low aqueous solution viscosity and excellent stability compared to other water-soluble polymers (the aqueous solution is difficult to gel). Therefore, sufficient applicability can be ensured and the concentration of the polyacrylamide resin in the paper substrate 2 can be increased.

As mentioned above, although the embodiment was shown and demonstrated about the sterilized paper of this invention, this invention is not limited to the said embodiment. Each configuration in the above embodiment, a combination thereof, and the like are examples, and the addition, omission, replacement, and other modifications of the configuration can be made without departing from the spirit of the present invention.
For example, another layer may be provided between the paper base 2 of the sterilized paper 1 and the heat bonding layer 3. Examples of other layers include a water vapor barrier layer, an oxygen barrier layer, a print layer, a printability improving layer, an overprint layer, and a light shielding layer. The other layer provided between the paper substrate 2 and the thermal bonding layer 3 may be one layer or two or more layers.
Moreover, you may have a printing layer on both surfaces of the paper base material 2 in the range which air permeability and peeling strength do not deviate from the meaning of this invention. An overprint layer may be further provided on the print layer.

  The present invention will be specifically described below with reference to examples. The present invention is not limited to these examples.

<Example 1>
[Manufacture of paper substrate]
Hardwood bleached kraft pulp (LBKP) was beaten with DDR so that the Canadian standard freeness described in JIS P 8121-2: 2012 was 350 mL to obtain a pulp slurry. An alkenyl succinic acid sizing agent (Fibrane 81K) which is absolutely dry and 0.5% sulfuric acid band is dispersed in the pulp slurry with cationized starch (Pillar 3YK, manufactured by Pillar Starch Co., Ltd.). 0.05%, amphoteric polyacrylamide resin paper strength enhancer (PAM) (trade name: Polystron OFT-3, manufactured by Arakawa Chemical Industries, Ltd., mass average molecular weight 3 million) 0.7% A papermaking raw material was obtained by adding 0.4% of an epichloro resin wet paper strength enhancer. After the papermaking raw material is made with a long paper machine to obtain a base paper, a gate roll coater attached to the papermaking machine is used to apply the following primer (A) on one side of the base paper to a coating amount after drying. It apply | coated and dried so that it might become 0.5 g / m < ² >. As a result, a paper substrate having a basis weight of 60 g / m ² and a density of 0.7 g / cm ³ was obtained.

  The content of the polyacrylamide resin in the obtained paper substrate was 1.5% by mass. In addition, one side and the other side of the paper base material, and a split surface (center plane) obtained by dividing the paper base material into two layers using an adhesive tape are used to perform thermal decomposition GCMS by cutting each part. When the concentration of the polyacrylamide resin on the opposite surface and the central surface was quantified and analyzed, the concentration of the polyacrylamide resin in the paper base material gradually decreased from one surface coated with the primer (A) toward the opposite surface side. It was confirmed that it was larger than the center plane on one side.

  Primer (A): An aqueous solution of anionic polyacrylamide resin (mass average molecular weight 200,000) (Polymerset (registered trademark) 512 manufactured by Arakawa Chemical Industries, Ltd.) was diluted with water to anionic polyacrylamide resin concentration of 9% by mass Adjusted).

[Manufacture of sterile paper]
50 parts by mass of an ethylene-vinyl acetate copolymer emulsion heat sealant (trade name: EA-H700, manufactured by Toyo Ink Co., Ltd.) and 50 parts by mass of an acrylic emulsion (trade name: Yodosol AE-41, manufactured by Henkel Japan) The mixture was mixed to prepare a heat sealant (D). Using a bar coater, apply the heat sealant (D) to the surface of the paper base primer (A) obtained above so that the coating amount after drying is 1.0 g / m ^2. And dried to form a thermal adhesive layer. Thereby, sterilized paper was obtained.

<Example 2>
In the production of the paper substrate of Example 1, a paper substrate and sterilized paper were produced in the same manner as in Example 1 except that the pulp freeness was changed to 550 mL.

<Example 3>
In the production of the paper substrate of Example 1, a paper substrate and sterilized paper were produced in the same manner as in Example 1 except that the basis weight of the paper substrate was 40 g / m ² . The content of the polyacrylamide resin in the obtained paper substrate was 2.0% by mass.

<Example 4>
In the production of the paper substrate of Example 1, a paper substrate and sterilized paper were produced in the same manner as in Example 1 except that the basis weight of the paper substrate was 150 g / m ² . Content of polyacrylamide resin in the obtained paper base material was 1.0 mass%.

<Example 5>
In the production of the paper base material of Example 1, the paper base material was prepared in the same manner as in Example 1 except that the coating amount after drying of the primer (A) on one side of the base paper was 8.0 g / m ^2. Sterile paper was produced. The content of the polyacrylamide resin in the obtained paper substrate was 10% by mass.

<Example 6>
In the production of the paper base material of Example 1, the paper base material was prepared in the same manner as in Example 1 except that the coating amount after drying of the primer (A) on one side of the base paper was 0.1 g / m ^2. Sterile paper was produced. Content of polyacrylamide resin in the obtained paper base material was 1.0 mass%.

<Example 7>
In manufacture of the sterilized paper of Example 1, it implemented except having used the heat seal agent (D) as the ethylene-vinyl acetate copolymer emulsion heat seal agent (E) (trade name: EA-H700, manufactured by Toyo Ink Co., Ltd.). A paper base and sterilized paper were produced in the same manner as in Example 1.

<Example 8>
In the production of the paper base of Example 1, 0.7% of cationized starch (pillar 3YK) instead of the amphoteric polyacrylamide resin paper strength enhancer (trade name: Polystron OFT-3, manufactured by Arakawa Chemical Industries, Ltd.) Was added, and the base material and sterilized paper were produced in the same manner as in Example 1 except that the coating amount after drying of the primer (A) on one side of the base paper was 1.0 g / m ² . . The content of the polyacrylamide resin in the obtained paper substrate was 2.5% by mass.

<Example 9>
In the production of the paper substrate of Example 1, a paper substrate and sterilized paper were produced in the same manner as in Example 1 except that the pulp freeness was changed to 650 mL.

<Example 10>
In the production of the paper base material of Example 1, the paper base material and sterilization were performed in the same manner as in Example 1 except that the coating amount after drying of the primer (A) on one side of the base paper was 16 g / m ^2. Paper was manufactured. The content of the polyacrylamide resin in the obtained paper substrate was 28% by mass.

  In any of Examples 2 to 10, when the concentration of polyacrylamide resin on the one surface, the opposite surface, and the center surface of the paper substrate was quantified and analyzed in the same manner as in Example 1, The polyacrylamide resin concentration was gradually decreased from one surface where the primer (A) was applied to the opposite surface side, and it was confirmed that the one surface was larger than the central surface.

<Comparative Example 1>
In the production of the paper substrate of Example 1, a paper substrate and sterilized paper were produced in the same manner as in Example 1 except that the primer (A) was not applied. Content of polyacrylamide resin in the obtained paper base material was 0.7 mass%.

<Comparative example 2>
In the production of the paper substrate of Example 1, the following undercoat (B) was used instead of the undercoat (A), and the coating amount after drying on one side of the base paper was 0.4 g / m ² . Except for the above, a paper base and sterilized paper were produced in the same manner as in Example 1. The content of the polyacrylamide resin in the obtained paper substrate was 0.9% by mass.

  Undercoat (B): A 4% by mass aqueous solution of polyvinyl alcohol (trade name: PVA117, manufactured by Kuraray Co., Ltd.).

<Comparative Example 3>
In the production of the paper substrate of Example 1, the following undercoat (C) was used instead of the undercoat (A) so that the coating amount after drying on one side of the base paper was 0.8 g / m ² . Except for the above, a paper base and sterilized paper were sequentially produced in the same manner as in Example 1. Content of polyacrylamide resin in the obtained paper base material was 0.7 mass%.

  Undercoat (C): 8 mass% aqueous solution of hydrophobized starch (trade name: GRS-T110, manufactured by Oji Cornstarch).

  In any of Comparative Examples 1 to 3, when the concentration of the polyacrylamide resin on the one surface, the opposite surface, and the center surface of the paper substrate was quantified and analyzed in the same manner as in Example 1, It was confirmed that the polyacrylamide resin concentration was substantially uniform throughout.

  In Table 1, for each of Examples 1 to 10 and Comparative Examples 1 to 3, the pulp freeness, the basis weight of the paper substrate, the type and amount of primer applied to the base paper, the type of heat sealant, and the paper base The content of polyacrylamide resin in the material is shown. In addition, the application amount (coating amount after drying) of the primer in each example is equal to the application amount as a water-soluble polymer (anionic polyacrylamide resin, polyvinyl alcohol, or hydrophobized starch) in the primer.

<Evaluation>
The following evaluation was performed on the sterilized paper obtained in each of Examples 1 to 10 and Comparative Examples 1 to 3, and the results are shown in Table 2.

[Measurement of Oken air permeability]
About each Example and each comparative example, the Oken type | formula air permeability of the obtained sterilized paper was measured according to JISP8121-2: 2012.

[Adhesion with film]
For each Example and each Comparative Example, the obtained sterilized paper and a composite film of polyethylene terephthalate (PET) resin and polyethylene (PE) resin were so arranged that the surface of the sterilized paper on the thermal adhesive layer side was in contact with the polyethylene resin side. Then, using a hot press tester, a thermocompression bonded material was prepared under the thermocompression bonding conditions of 150 ° C., 3.0 kgf / cm ² and 1.1 seconds. It was confirmed by peeling by hand at the time of thermocompression bonding. In this case, the evaluation was made by assuming that the bonding was possible and that the bonding was difficult.

[Measurement of peel strength and evaluation of substrate destruction]
The thermocompression product prepared by the above method was cut into a width of 15 mm to prepare a sample for measuring peel strength.

  The peel strength (gf / 15 mm) of the obtained peel strength measurement sample was measured according to JIS P 8113: 2006, using a tensile tester (model: Tensilon RTC-1250A, manufactured by Orientec Co., Ltd.) JIS P 8113: According to 2006, the sample PET, PE composite film, and sterilized paper were each chucked and measured by a 180 degree peel method at a peeling rate of 300 mm / min.

Further, when measuring the peel strength, the substrate destruction state of the sterilized paper was visually confirmed and evaluated according to the following criteria.
○: Substrate destruction did not occur.
(Triangle | delta): Although the sterilized paper was able to be peeled, the adhesion of the paper piece and the mark on the PET / PE film was seen.
X: Substrate destruction occurred.

  As shown in the above results, the sterilized papers of Examples 1 to 10 had a peel strength of 200 to 1000 gf / 15 mm in the peel test, and no substrate destruction was observed during the peel test. From these results, it was confirmed that it was excellent in easy peel suitability. On the other hand, about Comparative Examples 1-3, base-material destruction was seen at the time of a peeling test in the peeling test. Table 2 also shows that in Examples 1 to 10, sterilized paper having excellent air permeability is obtained. In particular, for Examples 1 to 4 and 6 to 9, sterilized paper exhibiting extremely excellent air permeability was obtained.

1 Sterile paper 2 Paper base 3 Thermal adhesive layer

Claims (9)

A paper base material, and a thermal adhesive layer laminated on one surface of the paper base material,
The paper base material is a sterilized paper containing a polyacrylamide resin on at least one of the surfaces and having a concentration of the polyacrylamide resin larger than that on the center surface on the one surface. The sterilized paper according to claim 1, wherein the paper base has a basis weight of 30 g / m ² or more.   The said thermal contact bonding layer contains the 1 type (s) or 2 or more types selected from the ethylene- (meth) acrylic acid copolymer, the ethylene- vinyl acetate copolymer, the acrylic ester polymer, polyethylene, and polybutene. 2. The sterilized paper according to 2.   The said paper base material is manufactured using the pulp whose freeness measured according to JISP8121-2: 2012 is 250 mL or more and 700 mL or less. Sterile paper.   The sterilized paper according to any one of claims 1 to 4, wherein the paper base material includes a polyacrylamide resin having a mass average molecular weight of 50,000 to 500,000.   The sterilized paper according to claim 5, wherein the paper substrate further comprises a polyacrylamide resin having a mass average molecular weight of 2 million to 10 million. A paper base material, and a thermal adhesive layer laminated on one surface of the paper base material,
The paper base material includes a polyacrylamide resin on at least the one surface;
The sterilized paper whose content of the said polyacrylamide resin in the said paper base material is 1.0-30 mass%.   A sterilized package obtained by thermocompression bonding the sterilized paper according to any one of claims 1 to 7 and a wrapping paper, a film, or a molded container for sterilization.   A peel strength when the wrapping paper, the film or the sterilized molded container is peeled from the sterilized package by 180 ° at a peeling speed of 300 m / min according to JIS P 8113: 2006 is 200 to 1000 gf / 15 mm. Item 10. The sterilized package according to Item 8.

Images