JP6975613B2 - Base paper for sterilization bags and sterilization bags - Google Patents

Description

The present invention relates to a base paper for a sterilization bag and a sterilization bag.

Medical instruments and the like are stored in a sterilization bag and sterilized, and when used for surgery or treatment, the sterilization bag is opened and taken out of the sterilization bag for use. As the sterilization bag, there are a bag made only of paper and a combination type bag made by heat-sealing the peripheral edges of paper (base paper for sterilization bag) and film. In recent years, the number of combination type sterilization bags whose contents can be confirmed by using a transparent film is increasing. In addition, the sterilization bag tends to be larger in size in order to improve the efficiency of the sterilization treatment amount.

Methods of sterilization using a sterilization bag include gas sterilization, steam sterilization, and radiation sterilization.
In gas sterilization, first, a sterilization bag (hereinafter, also referred to as "packaging") with a sealed opening is placed in a vacuum container to store the object to be sterilized such as medical equipment, and the vacuum container is depressurized and packaged. Exhaust the air inside the object. Then, a vacuum container is filled with a gas such as ethylene oxide gas, and the gas is permeated into the package to be sterilized. In steam sterilization, the package is exposed to high-temperature steam using an autoclave or the like, and sterilized by repeating depressurization and pressurization. In radiation sterilization, the package is sterilized by irradiating the package with radiation.

The characteristics required for the sterilization bag and the base paper for the sterilization bag include those shown below.
(1) Good air permeability (breathability) of gas and water vapor.
(2) There are no pinholes.
(3) The degree of size and wet strength (wet tensile strength) are high, and the water resistance is good.
(4) Peelability (the film and the base paper for the sterilization bag can be peeled off cleanly without tearing. Hereinafter referred to as paper peeling resistance), which is a characteristic necessary for removing medical instruments from the sterilization bag after sterilization. Be good.
(5) Have heat-sealing properties.
(6) Must be resistant to bag breakage under conditions such as sterilization.

As a base paper for sterilization bags that has both peeling and heat-sealing properties, for example, Patent Document 1 describes an acrylic copolymer and an alkyl ketene dimer on one side of a base paper containing an aluminate for pulp fibers. A base paper for a sterile bag provided with a coating layer containing (AKD) is disclosed. Further, Patent Document 2 discloses a sterilized paper in which a low air permeability base paper is impregnated with a specified amount of an impregnating agent containing a wax-containing core-shell type acrylic copolymer having specific physical properties as a main component.

Japanese Unexamined Patent Publication No. 9-290808 Japanese Unexamined Patent Publication No. 2005-307358

However, even with the inventions of Patent Document 1 and Patent Document 2, it may not be possible to say that the bag breaking resistance of the base paper for sterilization bags and the paper peeling resistance at the time of peeling are sufficient.

In the papermaking process, pulp fibers may be oriented depending on the papermaking equipment and papermaking conditions. In particular, when the papermaking speed is increased for the purpose of improving production efficiency, this tendency may become stronger. On the other hand, when the object to be sterilized is taken out from the sterilized sterilized bag, four sides are heat-sealed. When the sterilized base paper and the transparent film are peeled in a certain direction as usual, a side that receives a vertical peel load and a side that receives a horizontal peel load are generated with respect to the manufacturing direction of the sterilized base paper. Further, depending on the presence or absence of rewinding at the time of manufacturing the sterilization bag base paper, the mode in which the sterilization bag base paper and the transparent film are heat-sealed may reverse the manufacturing direction of the sterilization bag base paper and the peeling direction of the sterilization bag.
The inventor found that the paper peeling resistance at the time of peeling of the sterilization bag differs depending on the orientation of the pulp fibers in the forward direction, the reverse direction, or the lateral direction with respect to the papermaking direction. As a result, the present invention has been completed.

That is, an object of the present invention is to provide a base paper for a sterilized bag and a sterilized bag which have good peeling resistance at the time of peeling and excellent bag breakage resistance regardless of the direction in which the peel load is applied.

The present invention has the following aspects.
[1] A base paper for a sterilization bag made of at least pulp, an alkyl ketene dimer, and an acrylic resin, and the amount of the alkyl ketene dimer added is 0.1 part by mass to 0.4 parts by mass with respect to the mass of the pulp. are parts by weight, the acrylic resin is Ri 1.0g ^{/ m 2} ~8.0g ^/ m 2 der, sterile bag base paper, characterized in Rukoto that have a polypropylene.
[2] A base paper for a sterilization bag made of at least pulp, an alkyl ketene dimer, and an acrylic resin, and the amount of the alkyl ketene dimer added is 0.1 part by mass to 0.4 parts by mass with respect to the mass of the pulp. are parts by weight, the acrylic resin is ^{0.5g / m 2 ~4.0g / m 2} , the acrylic resin in a thickness direction of the sterile bag base paper is present with a concentration gradient,
Sterile bag base paper, characterized in Rukoto that have a polypropylene.
[3] A sterilization bag provided with the base paper for the sterilization bag according to [1] or [2] and a transparent film .
[4] The sterilization bag according to [3], wherein the heat-sealing layer of the transparent film is made of polypropylene .

According to the present invention, it is possible to provide a base paper for a sterilization bag and a sterilization bag having good peeling resistance at the time of peeling and excellent bag breakage resistance regardless of the direction in which the peel load is applied.

It is sectional drawing which shows typically the sterilization bag of the Embodiment of this invention. It is an SEM photograph of the base paper for a sterilization bag of Example 8 which is an Example of Embodiment of this invention. It is an SEM photograph of the base paper for a sterilization bag of Comparative Example 4 in which the acrylic resin which concerns on this invention was changed to polyvinyl alcohol (PVA).

[Base paper for sterilization bags]
The base paper for sterilization bags of the present invention (hereinafter, also simply referred to as “base paper”) is composed of at least pulp, an alkyl ketene dimer, and an acrylic resin, and the amount of the alkyl ketene dimer added is 0 with respect to the mass of the pulp. a .1 parts by 0.4 parts by mass, the acrylic resin is ^{1.0g / m 2 ~8.0g / m 2} . Alternatively, it is composed of at least pulp, an alkyl ketene dimer, and an acrylic resin, and the amount of the alkyl ketene dimer added is 0.1 part by mass to 0.4 part by mass with respect to the mass of the pulp, and the acrylic resin. there was ^{0.5g / m 2 ~4.0g / m 2} , the acrylic resin is present with a concentration gradient in the thickness direction of the sterile bag base paper.
In addition, having a concentration gradient means that there is a difference in the abundance of the acrylic resin between one side and the other side of the base paper for sterilization bags, and specifically, the abundance of the acrylic resin is 10%. It means that there is the above difference. The amount of the acrylic resin on the base paper for the sterilization bag may be confirmed by infrared spectroscopy (IR) on the samples obtained from one side and the other side of the base paper for the sterilization bag.
Hereinafter, the base paper for a sterilization bag of the present invention will be specifically described.

"First embodiment"
The base paper for a sterile bag of the present invention comprises at least pulp, an alkyl ketene dimer, and an acrylic resin. Hereinafter, the above-mentioned essential components and arbitrary components will be described in detail.

<Base paper, base paper>
The base paper of the present embodiment contains at least pulp, an alkyl ketene dimer, and an acrylic resin. The base paper of this embodiment contains at least pulp and an alkyl ketene dimer. The base paper is an intermediate in the process of producing the base paper.
The thickness of the base paper and the base paper is preferably 85 to 125 μm, more preferably 105 to 120 μm.
Base paper, basis weight of the base paper is preferably from ^{60~90g / m 2, 70~80g / m} 2 is more preferable.

(pulp)
Pulp is the main raw material for base paper and base paper.
Examples of the pulp include wood pulp, natural fiber, regenerated fiber, synthetic fiber and the like.
Examples of wood pulp include coniferous high-yield unbleached kraft pulp (HNKP; N material), coniferous bleached kraft pulp (NBKP; N material, NB material), broadleaf tree unbleached kraft pulp (LUKP; L material), and broadleaf tree bleached kraft pulp. Chemical pulp such as (LBKP, L material); mechanical pulp such as groundwood pulp (GP), pressure-rised groundwood pulp (PGW), thermomechanical pulp (TMP); Daneking pulp (DIP), waste pulp (WP) ) And other used paper pulp and semi-chemical pulp (CP).
Examples of natural fibers include pulp-like fibers such as cotton, straw, bamboo, esparto, bagasse, linter, Manila hemp, flax, hemp, jute, and goose bark.
These pulps may be used alone or in combination of two or more.

The pulp is preferably wood pulp, and preferably contains softwood bleached kraft pulp (NBKP; N material, NB material) from the viewpoint of long fiber length and high sheet strength.
The content of the softwood bleached kraft pulp is preferably 50 parts by mass to 80 parts by mass, and more preferably 60 to 70 parts by mass with respect to the total mass of the pulp raw material. If the content of the softwood bleached kraft pulp is less than 50 parts by mass or exceeds 80 parts by mass, the paper peeling resistance may be deteriorated.

The mass of pulp in the base paper for sterilization bags is the amount of ash by removing the organic substances such as acrylic resin, sizing agent, and paper strength agent from the base paper for sterilization bags with a solvent (pulp insoluble) and then burning the solvent insoluble matter. , And the amount of pulp may be obtained from the difference. Further, the amount of softwood bleached kraft pulp added may be discriminated from broad-leaved bleached kraft pulp or the like using a fiber length measuring instrument or the like after the base paper is separated, and the existence probability may be calculated.

(Alkyl ketene dimer)
Alkyl ketene dimer (hereinafter, also referred to as AKD) is a sizing agent and imparts water resistance to the base paper.

Examples of AKD include compounds represented by the following general formula (1).

In formula (1), R ¹ and R ² are independent alkyl groups having 8 to 30 carbon atoms.

The content of AKD is 0.1 to 0.4 parts by mass, preferably 0.1 to 0.2 parts by mass, based on the total mass of the pulp. If the amount of AKD is less than the above lower limit value, the paper peeling resistance may be deteriorated due to poor water resistance, and if it exceeds the above upper limit value, AKD may hinder the wettability of the acrylic resin to pulp.

The AKD in the base paper for a sterilization bag can be qualitatively and quantified by a Fourier transform infrared spectrophotometer or a gaz chromatography mass spectrometry method.

(Acrylic resin)
The acrylic resin imparts water resistance to the base paper and assists in paper peeling resistance and bag tear resistance. The acrylic resin may be added to the papermaking slurry in advance, or may be coated or impregnated on the papermaking base paper.
By keeping the amount of AKD added low, the fixing of the acrylic resin to the pulp is easily promoted. By covering the surface of the pulp fibers without blocking the gaps between the pulp fibers with the acrylic resin, the influence of the orientation of the pulp fibers is reduced, and the paper peeling resistance is achieved regardless of the direction in which the peel load is applied. It is possible to obtain properties with excellent bag breakage resistance. That is, when the base paper for sterilization bags is bonded to, for example, a transparent film at the time of heat sealing, the base paper for sterilization bags of the present invention in which voids remain on the surface exhibits an appropriate adhesive force required for bag breakage resistance. At the time of peeling, it is possible to suppress paper peeling due to excessive adhesive force. When the amount of AKD added is large, or when a sizing agent other than the acrylic resin is used, the voids between the pulp fibers tend to be closed. FIG. 3 is an SEM photograph of the base paper for a sterilization bag of Comparative Example 4 using polyvinyl alcohol as a sizing agent other than AKD. Comparing with the SEM photograph, it can be seen that the voids between the fibers are closed.

Any acrylic resin can be used, but a styrene acrylic resin, an ethylene acrylic acid copolymer, or the like can be preferably used. Among these, styrene acrylic resin is preferable from the viewpoint of easily covering the surface of pulp fibers without closing the voids between the pulp fibers.
These acrylic resins may be used alone or in combination of two or more.

The styrene-acrylic resin is a copolymer obtained by copolymerizing a styrene-based monomer and an acrylic-based monomer.
Examples of the styrene-based monomer include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, and the like. Examples thereof include p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, p-methoxy styrene and p-phenyl styrene.
These styrene-based monomers may be used alone or in combination of two or more.

Examples of the acrylic monomer include acrylic acid; methacrylic acid; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, stearyl acrylate, and phenyl acrylate. , Acrylic acid esters such as 2-ethylhexyl acrylate; methyl methacrylic acid, ethyl methacrylic acid, propyl methacrylic acid, n-butyl methacrylic acid, isobutyl methacrylic acid, n-octyl methacrylic acid, stearyl methacrylic acid. , Acrylic acid esters such as phenyl methacrylic acid; derivatives of acrylic acid such as acrylonitrile and acrylamide; derivatives of methacrylic acid such as metaacrylonitrile and metaacrylamide can be mentioned.
These acrylic monomers may be used alone or in combination of two or more.

The styrene-acrylic resin may have a monomer unit (another monomer unit) other than the styrene-based monomer unit and the acrylic-based monomer unit.
Examples of other monomers include ethylene unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; vinyl esters such as vinyl chloride, vinyl bromide, vinyl acetate and vinyl butyrate; vinyl methyl ether and vinyl ethyl ether. Such as vinyl ethers; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone can be mentioned.
These acrylic monomers may be used alone or in combination of two or more.

Acrylic resin content in the base paper ^{is 1.0g / m 2 ~8.0g / m 2} , 6.0g / m 2 ~7.5g / m 2 is more preferable. If the amount of the acrylic resin is less than the above lower limit, the water resistance of the base paper may be lowered, and the paper peeling resistance and the bag breaking resistance may be deteriorated. If the amount exceeds the above upper limit, the bag breaking resistance may be deteriorated. There is. In the base paper for sterilization bags of the first embodiment, there is no substantial difference in the amount of acrylic resin present on one side and the other side of the base paper.

The acrylic resin in the base paper for sterilization bags can be qualitatively and quantified by a Fourier transform infrared spectrophotometer or gas chromatography mass spectrometry.

<Other ingredients>
The base paper may contain components other than pulp, AKD, and an acrylic resin.
Other components include dry paper strength agents, wet paper strength agents, polyolefin resins, dyes, pH adjusters, slime control agents, defoaming agents, viscous agents and the like. Hereinafter, the dry paper strength agent, the wet paper strength agent, and the polyolefin resin will be described in detail.

(Dry paper force agent)
The dry paper strength agent imparts drying strength to the base paper.
Examples of the dry paper strength agent include amphoteric polymers such as amphoteric polyacrylamide resin; anionic polymers such as anionic polyacrylamide resin; and cationic polymers such as cationic polyacrylamide resin. Among these, an amphoteric polymer is preferable, and an amphoteric polyacrylamide resin is particularly preferable, from the viewpoint of fixing property with pulp and other internal additives.
These dry paper strength agents may be used alone or in combination of two or more.

The content of the dry paper force agent is preferably 0.5 to 1.5 parts by mass, more preferably 0.6 to 1.0 part by mass with respect to the total mass of the pulp. When the content of the dry paper strength agent is not less than the above lower limit value, it is easy to obtain a base paper having high drying strength, and when it is not more than the above upper limit value, it is easy to maintain good air permeability.

(Wet paper force agent)
The wet paper strength agent imparts wet strength (strength when wet with water) to the base paper.
Examples of the wet paper strength agent include polyamide polyamine / epichlorohydrin resin (hereinafter, also referred to as “epicrol resin”), melamine / formaldehyde resin, urea / formaldehyde resin, and the like. Among these, epichloro resin is preferable from the viewpoint of wide usable pH range of papermaking, no formaldehyde, and high wetting power.
These wet paper strength agents may be used alone or in combination of two or more.

The content of the wet paper force agent is preferably 0.1 to 1.5 parts by mass, more preferably 0.6 to 1.0 parts by mass with respect to the total mass of the pulp. When the content of the wet paper strength agent is not less than the above lower limit value, it is easy to obtain a base paper having high wetting strength at the time of sterilization, and when it is not more than the above upper limit value, it is easy to maintain good air permeability.

(Polyolefin resin)
The polyolefin resin functions as an adhesive aid when the base paper and the transparent film are heat-sealed. The polyolefin resin has the function of assisting the adhesive force in the adhesive part while limiting the adhesive force with the transparent film etc. by covering the pulp fiber surface without blocking the voids between the pulp fibers. By carrying it, it has the effect of facilitating the improvement of paper peeling resistance and bag tear resistance.
The polyolefin resin refers to a polymer synthesized using olefins and alkenes as monomers. Among these, polyethylene and polypropylene are preferable in that it is easy to secure the adhesive force of the transparent film with the heat sealant.

The content of the polyolefin resin is preferably 1 to 20 parts by mass, more preferably 3 to 10 parts by mass, still more preferably 4 to 10 parts by mass with respect to the total mass of the pulp.

Polyolefins in the base paper for sterilization bags can be qualitatively and quantified by a Fourier transform infrared spectrophotometer or gas chromatography-mass spectrometry.

<Manufacturing method>
Hereinafter, an embodiment of a method for manufacturing a base paper for a sterile bag according to the first embodiment will be described. In the present embodiment, the base paper for a sterilization bag of the present invention is obtained by applying an acrylic resin on both sides of the base paper, but the method of adding the acrylic resin can also be impregnated from one side of the base paper. It is good, and instead of such post-processing, for example, a method of adding it to a papermaking slurry can be taken.
The method for producing the base paper for a sterile bag of the present embodiment includes the following steps (I-1) to (I-3).
Step (I-1): A step of mixing a raw material containing pulp and AKD to prepare a raw material slurry (I).
Step (I-2): A step of wet-making a raw material slurry (I) to obtain a base paper (I).
Step (I-3): A step of applying a coating liquid (I) containing an acrylic resin to both surfaces of the base paper (I) obtained in the step (I-2).

(Step (I-1))
The step (I-1) is a step of mixing pulp, AKD, and other components (A) as needed to prepare a raw material slurry (I).
It is preferable to beat the pulp in advance. The beating can be appropriately performed by a beating machine such as a single disc refiner (SDR), a double disc refiner (DDR), and a beater. The degree of beating is preferably 40 ° SR or less, more preferably 20 to 35 ° SR.

The raw material slurry (I) is obtained by dispersing pulp, AKD, and if necessary, other components (A) and the like in water.
In the step (I-1), AKD is mixed so as to be 0.1 to 0.4 parts by mass with respect to the total mass of the pulp.

(Step (I-2))
The step (I-2) is a step of wet-making the raw material slurry (I) to obtain a base paper (I).
The wet paper machine used in the step (I-2) is not particularly limited, and is a paper machine applied to general paper making technology, specifically, a long net paper machine, a circular net paper machine, an inclined paper machine, and a twin. A wire paper machine can be used.

(Step (I-3))
The step (I-3) is a step of applying a coating liquid (I) containing an acrylic resin to both surfaces of the base paper (I) obtained in the step (I-2).
The coating liquid (I) is obtained, for example, by dispersing an acrylic resin in a solvent such as water.
The coating liquid (I) may contain other components if necessary.

Dry coating amount of the acrylic resin in the coating liquid (I) ^is set to be ^{1.0g / m 2 ~8.0g / m 2} .
Specifically, the total amount of the acrylic resin coated in the coating liquid (I) at the time of drying is 1.0 g / m ^{2 to} 8.0 g / m ² , and 6.0 g / m ^{2 to} 7.5 g. / M ² is more preferred.

The coating method of the coating liquid (I) is not particularly limited, and examples thereof include coating methods such as size press coating, road coater, squeeze coater, blade coater, air knife coater, and transfer coater.

By drying the coating liquid (I) coated on the base paper (I), a base paper for a sterilization bag can be obtained.

In addition to the method of adding the acrylic resin by coating, the method of adding a powdery or fibrous resin to the raw material slurry or the method of introducing the acrylic resin into the base paper for a sterilization bag by impregnation or the like may be used. Coating or impregnation is preferable in that the acrylic resin is easily located near the surface of the base paper for sterilization bags.

FIG. 2 is an SEM image of the base paper for a sterile bag of Example 8 composed of pulp, AKD, styrene acrylic resin, dry paper strength agent, wet paper strength agent, and polypropylene resin. On the other hand, FIG. 3 is an SEM image of the base paper for a sterile bag of Comparative Example 4, which comprises pulp, AKD, a dry paper strength agent, a wet paper strength agent, and polyvinyl alcohol. It can be seen that the base paper for the sterilization bag of FIG. 2 has gaps between the pulp fibers as compared with the base paper for the sterilization bag of FIG.

<Action effect>
The base paper for a sterile bag of the present embodiment described above is formed of at least pulp and a predetermined amount of AKD and an acrylic resin. A predetermined amount of AKD ensures the necessary water resistance inside the base paper, and a predetermined amount of acrylic resin further enhances the water resistance and secures voids between the pulp fibers, in other words, permeates into the pulp fibers or pulp fibers. By forming the arrangement according to the morphology of the above, the exposure of the pulp fibers is obscured and the influence of the orientation of the pulp fibers is reduced. As a result, it is possible to obtain characteristics having excellent paper peeling resistance regardless of the direction in which the peel load is applied. Further, it is considered that the above-described embodiment can generate an appropriate adhesive force between the heat-sealing agent and the base paper when heat-sealed with the transparent film, and can also utilize the anchor effect.
Therefore, the base paper for sterilization bags of the present invention has the effect of being excellent in paper peeling resistance and having the necessary bag breaking resistance regardless of the direction in which the peel load is applied.
In addition, since the acrylic resin is applied to both sides of the base paper, there is an advantage that the heat-sealed surface can be selected at the time of bag making. The base paper for sterilization bags of the present embodiment is not limited to the above.

"Second embodiment"
The base paper for a sterilization bag of the present invention is a base paper for a sterilization bag, which is composed of at least pulp, an alkyl ketene dimer and an acrylic resin, and the acrylic resin has a concentration gradient in the thickness direction of the base paper for the sterilization bag. be. Hereinafter, the same as that of the first embodiment will be omitted.

Examples of the base paper, the pulp, the alkyl ketene dimer constituting the base paper, the acrylic resin, and other optional components are the same as those exemplified in the first embodiment.

<Manufacturing method>
Hereinafter, an embodiment of a method for manufacturing a base paper for a sterile bag according to the second embodiment will be described.
The method for producing the base paper for a sterile bag of the present embodiment includes the following steps (I-1) to (I-3).
Step (I-1): A step of mixing a raw material containing pulp and AKD to prepare a raw material slurry (I).
Step (I-2): A step of wet-making a raw material slurry (I) to obtain a base paper (I).
Step (I-3): A step of applying a coating liquid (I) containing an acrylic resin to one surface of the base paper (I) obtained in the step (I-2).

(Step (I-1))
The step (I-1) can take the same method as that exemplified in the first embodiment.

(Step (I-2))
As for the step (I-2), the same method as that exemplified in the first embodiment can be adopted.

(Step (I-3))
The step (I-3) is a step of applying the coating liquid (I) containing the acrylic resin to one surface of the base paper (I) obtained in the step (I-2).
The coating liquid (I) is obtained, for example, by dispersing an acrylic resin in a solvent such as water.
The coating liquid (I) may contain other components if necessary.

Dry coating amount of the acrylic resin in the coating liquid (I) ^is set to be ^{0.5g / m 2 ~4.0g / m 2} .
Specifically, the total amount of the acrylic resin coated in the coating liquid (I) at the time of drying is 0.5 g / m ^{2 to} 4.0 g / m ² , and 3.2 g / m ^{2 to} 3.7 g. / M ² is preferable.

The coating method of the coating liquid (I) is not particularly limited, and examples thereof include coating methods such as size press coating, road coater, squeeze coater, blade coater, air knife coater, and transfer coater.
Since the base paper (I) is a breathable paper, the coated acrylic resin permeates the voids of the base paper (I). As a method of appropriately suppressing this, it is preferable to take a method of coating the surface opposite to the coated surface while supplying, for example, water or air. By adopting such a method, it is possible to obtain a base paper for a sterilization bag in which the acrylic resin has a concentration gradient in the thickness direction.

Next, the coating liquid (I) coated on the base paper (I) is dried to obtain a base paper for a sterilization bag.

<Action effect>
The base paper for a sterilization bag of the present embodiment described above is formed of at least pulp and a predetermined amount of AKD and an acrylic resin, and the acrylic resin is more present on the surface to be heat-sealed with a transparent film or the like. A predetermined amount of AKD ensures the necessary water resistance inside the base paper, and a predetermined amount of acrylic resin present on the surface to be heat-sealed with a transparent film or the like further enhances the water resistance and secures voids between pulp fibers. In other words, the penetration into the pulp fibers or the arrangement along the morphology of the pulp fibers obscures the exposure of the pulp fibers and reduces the influence of the orientation of the pulp fibers. As a result, it is possible to obtain characteristics having excellent paper peeling resistance regardless of the direction in which the peel load is applied. Further, it is considered that the above-described embodiment can generate an appropriate adhesive force between the heat-sealing agent and the base paper when heat-sealed with the transparent film, and can also utilize the anchor effect.
Therefore, the base paper for sterilization bags of the present invention has the effect of being excellent in paper peeling resistance and having the necessary bag breaking resistance regardless of the direction in which the peel load is applied.
In addition, since the acrylic resin is applied to one side of the base paper, there is an economic advantage. The base paper for sterilization bags of the present embodiment is not limited to the above.

"Sterile bag"
The sterilization bag of the present invention includes the above-mentioned base paper for the sterilization bag of the present invention.
Examples of the form of the sterilization bag include a combination type in which the base paper for the sterilization bag and the peripheral edges of the film are heat-sealed to make a bag. The film may be transparent or opaque.

The film may have a single-layer structure or a laminated structure, but when the balance between the strength of the film and the heat-sealing property is taken into consideration, the film having a laminated structure in which the heat-sealing layer is laminated on the base film ( Laminated film) is preferred. An intermediate layer printed or the like may be provided between the base film and the heat seal layer.
Examples of the resin constituting the base film include polyethylene terephthalate (PET) and the like.
Examples of the resin constituting the heat seal layer include polyolefins such as polyethylene (PE) and polypropylene (PP).
As the resin constituting the intermediate layer, a material used for a base film or a heat seal layer can be applied.

As the transparent film, a laminated film in which a film containing polypropylene as a main component is laminated on a film containing PET as a main component is preferable. Here, the "main component" refers to a component that occupies 90% by mass or more, preferably a component that occupies 95% by mass or more, and may be a component that occupies 100% by mass. By using polypropylene as a heat sealant, it is easy to obtain the effect of easily improving the bag breakage resistance, for example, when polypropylene is added to the base paper for sterilization bags.

The combination type sterilization bag can be obtained, for example, by superimposing a film of a predetermined size and a base paper for a sterilization bag and heat-sealing the peripheral edges on three sides. At this time, the film is laminated so that the heat seal layer is inside the sterilization bag, and the base paper for the sterilization bag is overlapped so that the side on which the acrylic resin is sufficiently present is inside the sterilization bag.

Further, in the case of continuous production of combination type sterilization bags, it is preferable to produce them as follows, for example.
First, the sterilization bag base paper is unwound from the roll of the sterilization bag base paper wound into a roll while niping with a pair of guide rolls.
Separately, the film is unwound from the winding body of the film wound in a roll shape while niping with a pair of guide rolls.
Next, the unwound base paper for a sterilization bag and the film are superposed, heat-sealed at both ends in the longitudinal direction (traveling direction), and then wound into a roll to obtain a wound body of the sterilization bag. At this time, the film is laminated so that the heat seal layer is inside the sterilization bag, and the base paper for the sterilization bag is overlapped so that the side on which the acrylic resin is sufficiently present is inside the sterilization bag.

When using a sterilization bag winder, unwind the sterilization bag from the sterilization bag winder, cut it perpendicular to the feeding direction so that it has the desired size, and heat-seal one end. do. Cutting and heat sealing may be performed at the same time, or cutting may be performed after heat sealing. By doing so, a sterile bag having heat-sealed peripheral edges on three sides can be obtained.

When the sterilization bag is continuously produced by the above method, the sterilization bag base paper and the film are heat-sealed at both ends in the longitudinal direction (traveling direction) at an arbitrary position in the longitudinal direction (traveling direction). On the other hand, heat sealing may be performed in the vertical direction as well. Then, by cutting in the direction perpendicular to the longitudinal direction (traveling direction), a sterile bag having heat-sealed peripheral portions on three sides can be obtained. The cutting position is not particularly limited as long as the three peripheral edges of the obtained sterile bag are heat-sealed and the other one is open, but the vicinity of the heat-sealed portion in the vertical direction is preferable.

<Action effect>
The sterilization bag of the present embodiment described above is composed of at least pulp, a base paper for sterilization bags made of a predetermined amount of AKD and an acrylic resin, and, for example, a transparent film. The base paper for sterilization bags has the necessary water resistance secured inside the base paper by a predetermined amount of AKD, and the water resistance is further enhanced by the predetermined amount of acrylic resin existing on the surface to be heat-sealed with a transparent film or the like. By securing voids between pulp fibers, in other words, permeating into pulp fibers or arranging them according to the morphology of pulp fibers, the exposure of pulp fibers is obscured and the influence of the orientation of pulp fibers is reduced. NS. As a result, it is possible to obtain characteristics having excellent paper peeling resistance regardless of the direction in which the peel load is applied. Further, it is considered that the above-described embodiment can generate an appropriate adhesive force between the heat-sealing agent and the base paper when heat-sealed with the transparent film, and can also utilize the anchor effect. Further, when polypropylene is contained in the base paper for a sterilization bag and polypropylene is contained in the heat seal layer of the transparent film, it is possible to have higher paper peeling resistance and bag tear resistance.
Therefore, the sterilized bag of the present invention has the effect of being excellent in paper peeling resistance and having the required bag breaking resistance regardless of the peel load from any direction.
The sterilization bag of the present embodiment is not limited to the above-mentioned one.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.

"component"
The raw materials and compounds used in each example are as follows.
-NBKP: Coniferous bleached kraft pulp.
-LBKP: Hardwood bleached kraft pulp.
-Polypropylene PZ: Polypropylene fiber (manufactured by Daiwabo Polytech, trade name: "Polypropylene PZ")
-AF255: Polyamide polyamine / epichlorohydrin resin (manufactured by Arakawa Chemical Industry Co., Ltd., trade name: "Alafix 255").
PS1280: Amphoteric polyacrylamide resin (manufactured by Arakawa Chemical Industry Co., Ltd., trade name: "Polytron 1280").
AD-1640: Alkyl ketene dimer (manufactured by Seiko PMC Corporation, trade name: "size agent AD-1640").
SE2016: Styrene acrylic resin (manufactured by Seiko PMC Corporation, product name: "SE2016").
-T-350: Polyvinyl alcohol (manufactured by Nippon Synthetic Chemistry Co., Ltd., trade name: "Gosenol T-350")

"Measurement / evaluation"
<Measurement of air permeability>
The air permeability of the base paper for sterilization bags was measured in accordance with "Paper and paperboard-Air permeability and air permeability resistance test method (intermediate region) -Garley method" described in JIS P 8117.

<Measurement of delamination strength>
Japan Technical Association of the Pulp and Paper (JAPAN TAPPI) Paper and Pulp Test Method No. The delamination strength of the base paper for sterilization bags was measured according to "Paperboard-Peeling Strength Test Method for Peeling Layers-" described in 19-1: 2000.

<Measurement of size>
The size of the base paper for sterilization bags was measured in accordance with "Paper and Paperboard-Size Test Method-Skihito Method" described in JIS P 8122.

<Measurement of wet tensile strength>
The wet tensile strength of the base paper for sterilization bags was measured according to "Paper and paperboard-wet tensile strength test method-" described in JIS P 8135.

<Evaluation of paper peeling property>
"Preparation / measurement"
1. 1. Cut the base paper for sterilization bags into A4 size and adjust the humidity (23 ° C, 50% RH) for 1 hour.
2. 2. Using a heat sealer (manufactured by Hogy Medical Co., Ltd .: bag sealer HS-400), a polypropylene resin heat seal layer was laminated on a base paper for sterilization and a PET base film at a seal temperature of 200 ° C. and a pressurization time of 2.5 seconds. The three sides of the film are bonded together with a bonding width of 20 mm.
3. 3. The heat-sealed sterile bag is again humidity-controlled (23 ° C., 50% RH) for 1 hour.
4. The sterilization bag after humidity control is cut into a width of 15 mm with one side joined, and the base paper for the sterilization bag and the film are peeled off by 90 ° at a speed of 300 mm / min with Tencilon. By measuring the three sides, it is possible to reproduce the peeling in the papermaking direction, the reverse papermaking direction, and the lateral direction.
5. The peeled surface after peeling is evaluated according to the following evaluation criteria.
(Evaluation criteria)
5: No fluffing of fibers is visually observed.
4: There is very little fiber fluffing in a limited area.
3: There are very few fiber fluffs in some places.
2: The part where the fluffing of the fiber is conspicuous is in a limited range.
1: There is fluffing of fibers on the front surface.
If it is 5 to 2 in this evaluation method, it can be used as a sterilization bag without any practical problem.

<Bag resistance test>
"Preparation / measurement"
1. 1. Place the medical steel instrument in a stainless steel vat and place it in a sterile bag.
2. 2. Using a heat sealer (Hogy Medical Co., Ltd .: bag sealer HS-400), heat seal the opening at a sealing temperature of 200 ° C. and a pressurization time of 2.5 seconds, and steam sterilize at 135 ° C. for 30 minutes in an autoclave. I do.
3. 3. Visually observe the sterilization bag after steam sterilization and evaluate according to the following evaluation criteria.
(Evaluation criteria)
5: No bag breakage has occurred. Moreover, no partial peeling of the seal portion is observed.
4: No bag breakage occurred, but peeling of 0.5 mm or more and less than 3 mm was observed in a part of the seal portion in the width direction.
3: No bag breakage occurred, but peeling of 3 mm or more and less than 6 mm was observed in a part of the seal portion in the width direction.
2: No bag breakage has occurred, but peeling of 6 mm or more and less than 10 mm is observed in a part of the seal portion in the width direction.
1: Peeling is seen in the width direction of the heat seal portion.
If it is 5 to 2 in this evaluation method, it can be used as a sterilization bag without any practical problem.

<Measurement of heat seal strength>
The sealing strength (bonding strength) between the base paper for a sterilizing bag and the laminated film in the sterilizing bag was measured according to the physical property test "delamination strength" (formerly JIS P8139).

"comprehensive evaluation"
The paper peeling resistance (papermaking direction, reverse papermaking direction, lateral direction) and the result (score) of the bag breakage resistance test were calculated based on the following formulas, and a comprehensive evaluation was carried out based on the following evaluation criteria.
{(Paper peeling resistance (papermaking direction) + Paper peeling resistance (reverse papermaking direction) + Paper peeling resistance (horizontal direction)) ÷ 3 + Bag tear resistance test} ÷ 2
(Evaluation criteria)
◎: Paper peeling resistance is all 5, and the result of the bag tear resistance test is 5.
○ +: The average value of the results of the paper peeling resistance test in each direction is 4.0 or more and less than 5.0. ○: The average value of the results of the paper peeling resistance test in each direction is 3. 0 or more and less than 4.0 Δ: Paper peeling resistance in each direction and the average value of the results of the bag tear resistance test are 2.0 or more and less than 3.0 ×: Paper peeling in each direction and the result of the bag tear resistance test The average value of is less than 2.0

" Reference example 1"
<Manufacturing of base paper for sterilization bags>
70 parts by mass of NBKP and 30 parts by mass of LBKP were mixed and adjusted to a beating degree of 29 ° SR. 0.8 parts by mass and 0.15 parts by mass of alkyl ketene dimer (AD-1640) were added and dispersed in water so that the solid content concentration was 0.5% by mass to prepare a raw material slurry.
Separately, the styrene acrylic resin (SE2016) was dissolved in water so that the concentration became 10% by mass, and the coating liquid (I) was prepared.
Using a long net paper machine, the raw material slurry was wet-made so that the basis weight was 70 g / m ² and the thickness was 100 μm, and a base paper was obtained.
After applying the coating liquid (I) to one side of the base paper, it is dried with a dryer part, and the coating liquid (I) is also applied to and dried on the other side of the base paper to make styrene. A base paper for a sterilization bag of Reference Example 1 was obtained, in which the total amount of acrylic resin was 6.4 g / m ² and substantially the same amount of styrene acrylic resin was present on both sides of the base paper.

The delamination strength, air permeability, size, and wet tensile strength of the obtained base paper for sterilization bags were measured. The results are shown in Table 1.

<Manufacturing of sterile bags>
A laminated film in which a PP film was laminated on a PET film and a base paper for a sterilization bag were superposed, and the peripheral edges of three sides were heat-sealed to obtain a sterilization bag. At this time, the laminated films were laminated so that the PP film was inside the sterilization bag.
Using the obtained sterile bag, the paper peeling resistance (papermaking direction, reverse papermaking direction, lateral direction) and bag breakage resistance (heat seal strength, bag breakage resistance test) were evaluated. The results are shown in Table 1.

" Reference Examples 2 to 7, Examples 8 to 10, Reference Examples 11 to 16 "
Reference except that the raw material slurry was prepared so as to have the compounding composition shown in Table 2 and the concentration and the coating amount of the coating liquid (I) were adjusted so that the amount of the styrene acrylic resin became the value shown in Table 2. A base paper for sterilization bags and a sterilization bag were manufactured in the same manner as in Example 1, and various measurements and evaluations were performed. The results are shown in Table 1.

" Reference example 17"
A sterilized bag was manufactured in the same manner as in Reference Example 1 except that the laminated film in which the PP film was laminated on the PET film was changed to the laminated film in which the PE film was laminated on the PET film, and various measurements and evaluations were performed. rice field. The results are shown in Table 1.

" Reference example 18"
While supplying air to the surface opposite to the coated surface of the base paper, the coating liquid (I) is applied to the other surface, and then dried with a dryer part, and one side and the other side of the base paper are dried. ^{A base paper for sterilization bags having a total amount of styrene acrylic resin of 3.2 g / m 2} having a concentration gradient in the abundance of styrene acrylic resin on the surface was obtained, and the styrene acrylic resin coated surface and the laminated film were heat-sealed. Manufactured a base paper for a sterilization bag and a sterilization bag in the same manner as in Reference Example 1, and performed various measurements and evaluations. The results are shown in Table 1.

" Reference Example 19, Example 20"
Reference except that the raw material slurry was prepared so as to have the compounding composition shown in Table 2 and the concentration and the coating amount of the coating liquid (I) were adjusted so that the amount of the styrene acrylic resin became the value shown in Table 2. A base paper for a sterilization bag and a sterilization bag were manufactured in the same manner as in Example 18, and various measurements and evaluations were performed. The results are shown in Table 1.

"Comparative Examples 1 to 3"
The raw material slurry was prepared so as to have the compounding composition shown in Table 2, and the concentration and the amount of the coating liquid (I) were adjusted so that the amount of the styrene acrylic resin became the value shown in Table 2. A base paper for sterilization bags and a sterilization bag were manufactured in the same manner as in Example 1, and various measurements and evaluations were performed. The results are shown in Table 1.

"Comparative Example 4"
Except for the fact that the coating liquid (I) was changed from styrene acrylic resin to polyvinyl alcohol (PVA), the base paper and sterilization bag for the sterilization bag of Comparative Example 4 were manufactured in the same manner as in Example 1, and various measurements were performed. Evaluation was performed. The results are shown in Table 1.

As is clear from the results in Tables 1 and 2, the base paper for sterilization bags obtained in each example had excellent paper peeling resistance and sufficient bag breakage resistance. In particular, the combination of the base paper for a sterilizing bag having polypropylene of Examples 8 to 10 and the transparent film having a heat seal layer of polypropylene showed exceptional paper peeling resistance and bag tear resistance.
On the other hand, the base papers for sterile bags of Comparative Examples 1 and 4 had a low evaluation in the bag tear resistance test, and the results of Comparative Examples 2 and 3 were inferior in the paper peeling resistance.

10 Sterile bag 1 Base paper for sterilization bag 2 Film

Claims (4)

A base paper for sterilization bags made of at least pulp, alkyl ketene dimer, and acrylic resin.
The amount of the alkyl ketene dimer added is 0.1 part by mass to 0.4 part by mass with respect to the mass of the pulp.
The acrylic resin is 1.0g ^{/ m} 2 ~8.0g ^/ m are ^two der,
Sterile bag base paper, characterized in Rukoto that have a polypropylene. A base paper for sterilization bags made of at least pulp, alkyl ketene dimer, and acrylic resin.
The amount of the alkyl ketene dimer added is 0.1 part by mass to 0.4 part by mass with respect to the mass of the pulp.
The acrylic resin is ^{0.5g / m 2 ~4.0g / m 2} ,
The acrylic resin exists with a concentration gradient in the thickness direction of the base paper for sterilization bags .
Sterile bag base paper, characterized in Rukoto that have a polypropylene. A sterilization bag comprising the base paper for the sterilization bag according to claim 1 or 2 and a transparent film . The sterilization bag according to claim 3, wherein the heat-sealing layer of the transparent film is made of polypropylene .

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