JP4936949B2 - Sterilized paper - Google Patents

Description

  The present invention relates to sterilized paper used when sterilizing medical instruments and the like, and particularly suitably used as a combination type sterilization packaging bag combined with a synthetic resin film or a lid for a synthetic resin molded sterilization container. Related to sterilized paper.

In the medical field, medical instruments such as syringes, surgical gloves, and instruments used for surgery are sealed in sterilization packaging materials, and then gas sterilization using ethylene oxide gas, etc., and radiation using γ rays, etc. Sterilized or electron beam sterilized, and stored in a packaging material until used, and opened when used.
As a packaging material, a combination type wrapping paper of a synthetic resin film and sterilized paper, or a container in which a synthetic resin is molded and covered with sterilized paper is used.

  Properties required for sterilized paper for such applications include (1) prevention of bacteria entry and good sterilization gas permeability, (2) no pinholes, (3) medical instruments, etc. That is, the peelability is good when taking out and (4) heat sealing is possible.

  However, conventionally reported sterilized paper does not necessarily satisfy the required characteristics. For example, when sterilized paper made of cellulose fiber alone is used in combination with a synthetic resin, there is a problem that the peelability and heat sealability are poor. Moreover, although what blended the fiber form or powder of the thermoplastic resin in the cellulose fiber and the thing which impregnated the thermoplastic resin are also reported, it is difficult to make a peeling property and heat sealability compatible.

In view of this, a thermoplastic resin layer provided on the surface has been developed. For example, Patent Literature 1 discloses a sterilized bag paper having a coating layer containing an acrylic copolymer on a base paper containing aluminate, and Patent Literature 2 discloses a release layer composed of a resin and a pigment and its peripheral edge. A sterilization packaging bag having a heat seal layer provided in a portion is disclosed in Patent Document 3, and a sterilization bag paper provided with a coating layer mainly composed of crosslinked polyvinyl alcohol is disclosed.
However, these methods have problems such as insufficient peelability and heat sealability, improved peelability and heat sealability, but poor air permeability, and complicated processes. It was.
In view of this situation, the present inventors have previously reported a sterilized bag paper provided with a thermoplastic resin layer containing an inorganic filler or provided with a thermoplastic resin layer containing a specific synthetic resin ( Patent Document 4). Although this is suitably used for a sterilization packaging bag of a combination type combined with a film, when used as a lid for a molded sterilization container, there is a disadvantage that the peelability is inferior.

JP-A-9-290808 JP 2004-84131 A JP 2000-107268 A JP 2000-246840 A and JP 2001-122348 A

  The present invention is excellent in breathability, peelability and heat sealability, and can be used not only as a packaging bag for sterilization of combination type but also as a lid for molded sterilization containers. Sterilization used for gas sterilization using ethylene oxide gas or the like It is an object of the present invention to provide a sterilized paper that can also be used for paper and electron beam sterilization.

As a result of intensive studies in order to solve this problem, the present inventors have found that the problem can be solved by providing a specific thermoplastic resin layer on the base paper, and have reached the present invention.
That is, the present invention
(1) A sterilized paper having a thermoplastic resin layer provided on one side of a base paper, wherein the thermoplastic resin layer contains a polyolefin resin, an inorganic filler and a surfactant,
(2) The sterilized paper according to (1), wherein the thermoplastic resin layer further contains an acrylic resin or an ethylene-vinyl acetate copolymer,
(3) The sterilized paper according to (1) or (2), wherein the base paper is impregnated paper,
(4) The sterilized paper according to (3), wherein the impregnated paper is a polyester resin impregnated paper,
(5) A cover material for a synthetic resin molded sterilization container made of the sterilized paper according to any one of (1) to (4) above,
Is to provide.

  The sterilized paper of the present invention has good air permeability and can be suitably used for gas sterilization using ethylene oxide gas or the like, and is excellent in peelability and heat sealability for either synthetic resin films or synthetic resin molded products. is there. Furthermore, even when used for electron beam sterilization, which easily causes paper deterioration, a sterilized paper having excellent peelability and heat sealability can be obtained.

Hereinafter, the present invention will be described in detail.
The sterilized paper of the present invention is a base paper provided with a thermoplastic resin layer.
The base paper used in the present invention is obtained by wet papermaking of bleached wood pulp, but other natural fibers, synthetic fibers and the like can be used and used together as necessary. Various paper chemicals can be added to these. Moreover, what gave the resin impregnation process to this may be used.

Properties required for the base paper include good breathability, strength that does not stretch or break during processing or use, water resistance, etc., for example, uncoated sterile paper, fine paper, latex impregnation Examples of the paper include impregnated paper, particularly acrylic resin impregnated paper and polyester resin impregnated paper.
In particular, polyester resin-impregnated paper is more suitable because it has high paper strength, can withstand electron beam sterilization, and does not easily tear when opened.

  When the base paper is impregnated with a resin, the desired impregnation rate varies depending on the type of the resin and the composition of the thermoplastic resin layer applied thereafter. In general, it is desirable that the impregnating agent is 2 to 6% by weight based on the weight after impregnation. If the impregnation rate is too low, the peelability tends to decrease, and if the impregnation rate is too high, the air permeability is inferior.

The thermoplastic resin layer contains a polyolefin resin, an inorganic filler, and a surfactant.
Examples of the polyolefin resin include polyethylene resin and polypropylene resin, and specific examples include “Chemical (registered trademark)” manufactured by Mitsui Chemicals.

In order to increase the sealing strength, the thermoplastic resin layer may further contain an acrylic resin or an ethylene-vinyl acetate copolymer (EVA).
For example, when the base paper is an acrylic resin-impregnated paper, if the thermoplastic resin layer contains an acrylic resin, the sealing strength is further increased. Further, when the base paper is a polyester resin-impregnated paper, if EVA is contained in the thermoplastic resin layer, the sealing strength is further increased.

  Examples of the acrylic resin include homopolymers of acrylic monomers such as (meth) acrylic acid and derivatives thereof, and copolymers with other monomers that can be copolymerized. Among them, (meth) acrylic acid esters A copolymer of styrene, acrylonitrile and the like is preferable, and examples thereof include “Ultrazole” manufactured by Gantz Kasei.

Examples of inorganic fillers include clay, talc, kaolin, calcium carbonate, titanium dioxide, and aluminum hydroxide, and these can be used alone or in combination of two or more.
These inorganic fillers having a particle size of 0.1 to 15 μm, preferably 5 to 15 μm are desirable because good air permeability and peelability can be obtained.

  Examples of the surfactant include a cationic surfactant, an anionic surfactant, an amphoteric surfactant, a nonionic surfactant, and the like. Among these, a nonionic surfactant is preferable, for example, “New Coal” manufactured by Nippon Emulsifier. Etc. can be illustrated.

Preferred blending ratios of polyolefin resin, acrylic resin or EVA, inorganic filler, and surfactant in the thermoplastic resin layer are as follows.
The polyolefin resin is 20 to 40 parts by weight, preferably 30 to 35 parts by weight with respect to 100 parts by weight of the thermoplastic resin . The acrylic resin or EVA is 0 to 25 parts by weight, preferably 5 to 20 parts by weight. The total amount of polyolefin resin and acrylic resin or EVA is 28 to 65 parts by weight.
When there is too little polyolefin resin, the range of the temperature which can be heat-sealed appropriately will become small, and adjustment of sealing temperature will become difficult.
The lower the blending amount of the acrylic resin or EVA, the lower the heat sealability. On the other hand, if the blending amount is too high, the heat seal strength becomes too high and the peelability is inferior.
Further, other resins can be blended within a range not impairing these performances.

  The inorganic filler is added in an amount of 50 wt% to 250 wt%, preferably 75 wt% to 200 wt% of the total amount of the resin, such as polyolefin resin, acrylic resin, EVA and the like. If the amount of the inorganic filler is less than this, the air permeability is inferior, and if it is used beyond this, the inorganic filler falls off or the heat seal strength is lowered.

  The surfactant is added in an amount of 0.1 to 5% by weight based on the total amount of resin and filler. When the addition amount is small, the peelability is inferior, and when it is large, the air permeability is inferior, and the sizing degree decreases.

The coating amount of the thermoplastic resin layer is 1 to 30 g / ^{m 2,} preferably from 5 to 20 g / ^{m 2} is desirable. If the coating amount is less than this, the sealing strength and peelability are poor, and if it exceeds this, the air permeability is poor.

  The thermoplastic resin can be applied by on-machine coating provided in a paper machine or off-machine coating after paper making. The coating method is not particularly limited, and for example, a coater such as an air knife coater, a rod bar coater, or a blade coater and other known coating methods can be used.

Hereinafter, the present invention will be described in detail with reference to examples.
In addition, the characteristic in an Example was evaluated with the following method.
(1) Heat-sealability Sterile paper and polypropylene sheet are heat-sealed for 1.2 seconds (130 ° C) with a heat-seal machine (Automini AM-300RW), and T-shaped with a Tensilon tensile tester (lowering speed 300mm / min). Seal strength was measured by peeling. However, only Comparative Example 2 was evaluated with respect to heat sealing by changing the sealing temperature from 130 ° C to 140 ° C.
The heat seal strength is desirably 1.5 to 2.5 N / 10 mm, and more desirably 1.5 to 2.0 N / 10 mm.

(2) Peel property The state of paper breakage after the heat seal strength measurement was visually determined.
5: No paper break.
4: Slight fuzz is visible.
3: The fuzz is clearly visible.
2: Some paper breaks.
1: Paper breaks as a whole.
If the peel property is 4 or more in terms of an average of 4 times, there is no practical problem.

(3) Air permeability Measured according to JIS-P8117.
The air permeability is desirably 300 seconds or less.

Production Example 1
Beating to 550 ml CSF with pulp composition of NBKP 70% and LBKP 30%, 1.0% by weight of acrylamide paper strength enhancer (Polyaclon ST-13 manufactured by Seiko PMC), alkyl ketene dimer (size pine manufactured by Arakawa Chemical Industries, Ltd.) K-287) 0.8 wt%, epichloro resin wet paper strength enhancer (WS-525 manufactured by Seiko PMC) 1.0 wt%, basis weight 70 g / m ² , air permeability 12 seconds base Paper is made, and an impregnating agent in which 10% by weight of acrylic resin (Ultrazol UL-637 manufactured by Gantz Kasei) is blended with 90% by weight of acrylic resin (Ultrazol B-600 manufactured by Gantz Kasei Co., Ltd.) The base paper 1 was produced by impregnation so as to be 4% by weight with respect to the weight after impregnation.

Production Example 2
A base paper 2 was obtained in the same manner as in Production Example 1 except that the impregnation amount of the impregnating agent was 2 wt% in Production Example 1.

Production Example 3
A base paper 3 was obtained in the same manner as in Production Example 1 except that the impregnation amount of the impregnating agent was changed to 6% by weight in Production Example 1.

Production Example 4
The base paper 4 was produced by impregnating the base paper made in Production Example 1 with a polyester resin (Toyobo's Bironal MD-1480) so as to be 4% by weight based on the weight after impregnation.

Example 1
On base paper 1, polyolefin resin (Mitsui Chemicals, Chemipearl EP-150H) 35 parts by weight, acrylic resin (Gantz Kasei, Ultrazol B-600) 5 parts by weight, talc 60 parts by weight, surfactant (Japan) Emulsifier, New Coal TN-6618) A coating solution consisting of 1 part by weight was applied as a solid content at 12 g / m ² to prepare a sterilized paper of the present invention.
The evaluation results of the obtained sterilized paper are shown in Table 1 together with other examples and comparative examples.

Example 2
The same procedure as in Example 1 was performed except that the coating amount of the coating liquid was changed to 17 g / m ^{2 in} Example 1, and the sterilized paper of the present invention was obtained.

Example 3
In Example 1, it carried out similarly to Example 1 except having changed the addition amount of polyolefin resin in a coating liquid from 35 weight part to 40 weight part, and obtained the sterilized paper of this invention.

Example 4
In Example 1, the amount of talc in the coating solution was changed from 60 parts by weight to 50 parts by weight, and the amount of the acrylic resin added was changed from 5 parts by weight to 15 parts by weight. The sterilized paper of the present invention was obtained.

Example 5
In Example 1, it carried out similarly to Example 1 except having used the base paper 2 instead of the base paper 1, and obtained the sterilized paper of this invention.

Example 6
On base paper 4, polyolefin resin (Mitsui Chemicals, Chemipearl EP-150H) 35 parts by weight, ethylene-vinyl acetate resin (Toyo Morton, Adcoat AD37R345J) 5 parts by weight, talc 60 parts by weight, surfactant (Japan) Emulsifier, New Coal TN-6618) A coating solution consisting of 1 part by weight was applied as a solid content at 12 g / m ² to prepare a sterilized paper of the present invention.

Example 7
In Example 6, the amount of talc in the coating solution was changed from 60 parts by weight to 50 parts by weight, and the amount of ethylene-vinyl acetate resin added was changed from 5 parts by weight to 15 parts by weight. The sterilized paper of the present invention was obtained.

Comparative Example 1
In Example 1, it carried out similarly to Example 1 except not having added surfactant to the coating liquid, and obtained the sterilized paper. As shown in Table 1, the evaluation results were inferior in peelability.

Comparative Example 2
A coating liquid consisting of 35 parts by weight of ethylene-vinyl acetate resin (manufactured by Toyo Morton, Adcoat AD37R345J) and 65 parts by weight of talc was applied to the base paper 3 at a solid content of 12 g / m ² to prepare a sterilized paper. As shown in Table 1, the evaluation results were inferior in seal strength while having good peel properties. Furthermore, when the sealing temperature was changed from 130 degrees to 140 degrees and the heat sealing was performed, the sealing strength and the peelability were evaluated. As a result, the sealing strength was sufficient, but the peelability was inferior.

Evaluation example (electron beam processing)
The sterilized paper obtained in Example 6 and Example 7 was subjected to electron beam treatment at an irradiation dose of 60 kGy using an electron beam irradiation apparatus (Dynamitron 5 MeV electron accelerator manufactured by RDI), and then the seal strength and peel. Sex was measured.
As shown in Table 2, the evaluation results are good for both Example 6 and Example 7 using the base paper impregnated with the polyester-based resin, in terms of seal strength and peelability. It has been shown to withstand electron beam sterilization.

  As described above, since the sterilized paper of the present invention has good air permeability, excellent peelability and heat sealability, it can be used not only as a combination type sterilization packaging bag but also as a lid for molded sterilization containers. Can also be suitably used. Therefore, it can be applied to sterilization containers for articles that require sterilization, such as medical instruments, beauty products, hygiene products, and the like.

Claims (2)

In sterilized paper in which a thermoplastic resin layer is provided on one side of an acrylic resin or polyester resin impregnated paper, the thermoplastic resin layer is a polyolefin resin (excluding ethylene-vinyl acetate copolymer), acrylic resin or ethylene- A sterilized paper containing a vinyl acetate copolymer, an inorganic filler, and a surfactant. A cover material for a synthetic resin-made sterile container made of the sterilized paper according to claim 1.