JP5119134B2 - Laminated film for highly sublimable substance, packaging bag using the same, wound body, and method for producing laminated film for highly sublimable substance - Google Patents

Description

  The present invention relates to a laminated film for highly sublimable substances, a packaging bag using the same, and a method for producing a laminated film for highly sublimable substances.

  Conventionally, technical proposals relating to packaging films and packaging bags for handling highly sublimable substances such as iodine have been made (see, for example, Patent Document 1).

JP 2007-290740 A

However, the iodine packaging bag proposed in the above prior art is used as a bag (inner bag) accommodated in a so-called outer container such as a corrugated cardboard or a drum can. There is a problem that the surface tends to cause scratches and pinholes due to friction with the outer container surface.
Further, the iodine packaging bag proposed in the above prior art has a problem that the tear strength is not practically sufficient and it is easily torn once a crack or scratch is generated.
Furthermore, since the surface of the polyvinylidene chloride (PVDC) film is easily sticky, there is a problem that a dimensional shift or wrinkle is likely to occur particularly in the bag making process, and the handleability and the bag making yield are poor.
Therefore, in the present invention, in view of the above-mentioned problems of the prior art, it has practically sufficient resistance and barrier properties against so-called highly sublimable substances such as iodine, and the packaging operation of the substances is easy and can be automated. It is an object to provide a practically excellent film for a high sublimation substance having excellent handling properties, excellent scratch resistance under various usage environments such as packaging process and distribution process, and high tear strength. .

  In the invention of claim 1, a heat seal layer and a coating layer are sequentially laminated on the base material layer, the base material layer is made of a nonwoven fabric, and the heat seal layer is made of a stretched film made of polyvinylidene chloride. Thus, the coating layer provides a laminated film for a highly sublimable substance made of polyvinylidene chloride latex.

  In invention of Claim 2, it is a packaging bag formed by heat-sealing the laminated film for highly sublimable substances of Claim 1, Comprising: The said coating layer is an inner surface, The said base material layer is an exterior surface. A packaging bag for a highly sublimable substance is provided.

  In invention of Claim 3, the laminated film roll for highly sublimable substances in which the laminated film for highly sublimable substances of Claim 1 is wound is provided.

  In the invention of claim 4, a step of laminating a heat seal layer made of a stretched film made of polyvinylidene chloride on a base material layer made of nonwoven fabric, and a coating layer made of polyvinylidene chloride latex on the heat seal layer There is provided a method for producing a laminated film for a highly sublimable substance having a step of laminating.

It has practically sufficient resistance and barrier properties against so-called highly sublimable substances such as iodine, is excellent in content protection, easy to wrap the contents, can be automated, has excellent handling properties, packaging process and distribution It is possible to provide a film for a high sublimation substance and a packaging bag for a high sublimation substance that have excellent scratch resistance under various usage environments such as processes and have high tear strength.
In addition, a wound body of a film for a highly sublimable substance that has the above-described performance and does not have stickiness between films even when wound and can exhibit extremely excellent handling properties in a bag making process can be obtained.

  Hereinafter, the best mode for carrying out the present invention (hereinafter, this embodiment) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

[Laminated film for highly sublimable substances]
The laminated film for highly sublimable substances in the present embodiment (hereinafter sometimes simply referred to as a laminated film) has a configuration in which a heat seal layer and a coating layer are sequentially laminated on a base material layer. . The base material layer is made of nonwoven fabric, the heat seal layer is made of a stretched film made of polyvinylidene chloride (PVDC), and the coating layer is made of polyvinylidene chloride (PVDC) latex.

(Base material layer)
A base material layer is a layer which bears the mechanical strength of laminated | multilayer film, especially tensile strength. In addition, when used as a package, it also exhibits a function of preventing the laminated film from being broken or pierced by rubbing against an exterior such as a fiber drum.
Furthermore, when the laminated film is heat-sealed to form a packaging bag to be described later, it also functions as a heat-resistant layer that prevents the laminated film from being thermally deformed.
A base material layer consists of a nonwoven fabric, for example, a polyethylene nonwoven fabric, a polypropylene nonwoven fabric, a polyester nonwoven fabric etc. are mentioned.
In particular, since a polyester material is excellent in heat resistance, it is preferable as a base material layer constituting the laminated film in the present embodiment. Specifically, when producing a packaging bag using the laminated film in the present embodiment, the base material layer does not melt even if the heat seal layer melts at a high seal temperature, so that the seal portion can be formed reliably. In addition, the appearance is also improved.
(That represents the weight of the nonwoven fabric of 1 m ² in grams) basis weight per unit basis weight of the nonwoven fabric is preferably in the range of 10 to 100 g / m ^2, more preferably in the range of 20 to 70 g / m ^2, 30 to 60 g The range of / m ² is more preferable. By setting it as this range, the stickiness of a coating layer (PVDC latex) can be effectively absorbed in the finally obtained laminated film, and practically sufficient tear strength and sliding resistance can be exhibited.
The basis weight per unit basis weight of the nonwoven fabric can be calculated by sampling the nonwoven fabric to an arbitrary size, measuring the weight with a predetermined measuring instrument, and converting it to m ² .
If the basis weight of the non-woven fabric is large, the thickness of the non-woven fabric increases, so that the effect of improving the tear strength and the sliding resistance can be obtained.
If the basis weight is less than 10 g / m ² , for example, it may be torn or broken in the packaging process until it is accommodated in a fiber drum or the like, and furthermore, the sticky absorption of the coating layer (PVDC latex) becomes insufficient.
When the basis weight exceeds 100 g / m ² , the sticky absorption effect and slip resistance of the coating layer can be sufficiently obtained, but the texture of the laminated film is deteriorated. For example, a material such as iodine is added to a packaging bag made of this laminated film. In addition, when this is housed in a fiber drum can or the like which is an exterior, shape followability is poor, it is difficult to follow, and packaging workability may be deteriorated.
The thickness of the base material layer is preferably 0.05 to 1.00 mm, more preferably 0.10 to 0.50 mm, and still more preferably 0.15 to 0.3 mm in consideration of the basis weight.
From the above, the following effects (1) to (3) are exhibited by using a nonwoven fabric as the base material layer constituting the laminated film in the present embodiment.
(1) Since the tear strength is large, even if cracks or scratches enter, the film is not easily torn and the film is not torn.
(2) It has excellent slidability and rub resistance, and even when it is frictionally worn with the exterior of a cardboard box, fiber drum can, etc., it is difficult to break the bag and is excellent in content protection.
(3) Since there is almost no stickiness, it is peeled off when the film is unwound in a subsequent process (slit, bag making, etc.) in a state where it is wound into a roll and the base material layer (front) and the sealing layer (back) are in contact. Less resistance, less dimensional variation, and better workability. Moreover, the handleability of the packaging bag is improved.

(Heat seal layer)
The heat seal layer is made of a stretched film made of polyvinylidene chloride (hereinafter sometimes simply referred to as PVDC).
The stretched film made of PVDC forming the heat seal layer is obtained by melt-extruding a monomer mixture that becomes PVDC to form a film and stretching. By stretching and providing orientation, the film is less likely to crack even if it is bent or deformed. The stretching may be uniaxial stretching, but biaxial stretching is preferred because cracks are less likely to occur.

PVDC may be a polymer of vinylidene chloride alone or may be a copolymer with other monomers, but a copolymer is preferred in order to improve the extrusion processing characteristics.
Examples of the copolymerizable monomer include acrylic acid esters such as vinyl chloride, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl acrylate, methyl methacrylate, and glycidyl methacrylate. Methacrylic acid esters such as acrylonitrile, methacrylonitrile, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid and maleic acid.
These may be used alone or in combination of two or more.

In order to ensure the high barrier property with respect to a highly sublimable substance, content of vinylidene chloride in PVDC shall be 50 mass% or more, and 80-97 mass% is preferable.
A heat stabilizer, a plasticizer, a slip agent, etc. can be added to PVDC as needed.

  A known method can be applied to the method for producing the stretched film made of PVDC. For example, it is possible to apply a tubular stretching method that extrudes into a tube shape from a circular die and pressurizes air to simultaneously stretch biaxially.

  The heat seal layer can be formed by laminating the above-described PVDC stretched film into the base material layer shape with a predetermined adhesive.

(Coating layer)
The coating layer is made of polyvinylidene chloride (PVDC) latex.
PVDC latex is obtained by dispersing and emulsifying PVDC in water by a known method.
PVDC may be a polymer of vinylidene chloride alone or a copolymer with other monomers, but a copolymer is preferred in order to obtain good low temperature heat sealability.
Examples of the copolymerizable monomer include acrylic acid esters such as vinyl chloride, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl acrylate, methyl methacrylate, and glycidyl methacrylate. And carboxylic acid esters such as acrylonitrile, methacrylonitrile, and unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid and maleic acid.
These may be used alone or in combination of two or more.

The content of vinylidene chloride in PVDC needs to be 50% by mass or more, and preferably 80 to 92% by mass in order to ensure barrier properties against highly sublimable substances.
You may add emulsifiers, such as surfactant, pH adjusters, such as ammonia, etc. to PVDC latex as needed.
Further, since the coating layer becomes a heat seal surface of the laminated film, a predetermined lubricant may be added to improve the slipperiness of the laminated film, and an antiblocking agent may be added to prevent blocking. .

  The coating layer can be formed by forming a thin layer by applying, coating, transferring, spraying, etc. PVDC latex, followed by drying treatment. Alternatively, the PVDC latex may be formed into a thin film by a casting method or the like, and may be laminated with the above-described PVDC stretched film without being stretched to form a coating layer.

The role of the heat seal layer (PVDC stretched film) and the coating layer (PVDC latex) described above will be described.
The heat seal layer (PVDC stretched film) bears barrier properties and resistance to highly sublimable substances.
PVDC has high crystallinity and is brittle as it is, and easily cracks due to bending or deformation due to heat sealing pressure. However, it does not crack even if it is bent or deformed by stretching and orientation.
On the other hand, since PVDC has high crystallinity, it is crystallized into a layer when stretched, and therefore, cohesive failure tends to occur so that it peels off in a mica-like manner against a stress that is pulled in the thickness direction of the film. For this reason, when it is set as the structure in which only the heat seal layer (PVDC stretched film) was formed, when utilizing a laminated | multilayer film for a packaging bag etc., practically sufficient intensity | strength cannot be obtained.

However, when the coating layer made of PVDC latex is formed on the heat seal layer (PVDC stretched film), the occurrence of the cohesive failure described above can be effectively prevented.
This is because by providing the coating layer, the tensile stress described above is once applied to the coating layer, causing a shift in the direction of the stress, and this shift relaxes the stress applied to the heat seal layer and makes it difficult to cause cohesive failure. This is probably because of this.

  Moreover, when it is set as the structure which formed the coating layer (PVDC latex) directly on the base material layer without providing a heat seal layer (PVDC stretched film), since the orientation of the crystal of PVDC is not applied, it is brittle as a whole, Cracks occur due to deformation caused by heat seal pressure. As a result, when a highly sublimable substance is handled, this substance penetrates and causes weight loss, alteration, peeling of the laminated film, and strength reduction.

Moreover, the film thickness of the coating layer (PVDC latex) is 3 μm or more and 20 μm or less in order to relieve stress applied to the heat seal layer (PVDC stretched film) and obtain sufficient heat seal strength in the laminated film in the present embodiment. Is preferable.
In addition, the thickness of the heat seal layer (PVDC stretched film) is preferably 10 μm or more in order to prevent weight loss, alteration, peeling of the laminated film, and strength reduction when handling highly sublimable substances, and good handleability. In order to ensure this, it is preferable that the thickness be 50 μm or less.

(Middle layer)
The laminated film in this embodiment may have a configuration in which an intermediate layer is provided between the base material layer and the heat seal layer.
As a material for the intermediate layer, a polyolefin resin is suitable. By providing the intermediate layer of the polyolefin resin, it is possible to further improve the mechanical strength without hardening the laminated film, and to prevent the tearing due to friction with the exterior.
As polyolefin resin, a well-known thing can be used. For example, high pressure method low density polyethylene, linear low density polyethylene, medium density polyethylene, polyethylene such as high density polyethylene, polypropylene homopolymer, block copolymer, random copolymer, etc. polypropylene, polybutene, polymethylpentene, ethylene-vinyl acetate Examples thereof include a copolymer, an ethylene-acrylic acid ester copolymer, an ethylene-acrylic acid copolymer, and an ionomer.
The film thickness of the intermediate layer is preferably 10 μm or more in order to sufficiently secure the strength of the laminated film in the present embodiment. For example, in order to ensure sufficient softness and handleability as a packaging bag material. Is preferably 100 μm or less.
The intermediate layer is formed by, for example, a method in which a polyolefin resin film is bonded to a base material layer and a heat seal layer by a dry laminating method, or a method in which the base material layer and the heat seal layer are bonded to each other by an extrusion sand laminating method ( For example, melted polyethylene between a base material layer and a heat seal layer is extruded and laminated into a base material layer / intermediate layer (PE) / heat seal layer), and a polyolefin resin film is extruded by a sand lamination method. A method of laminating with a material layer and a heat seal layer (in order to form a laminate film having a total thickness of about 100 μm, for example, first, melted polyethylene is extruded and laminated between a base material layer and a polyolefin film to form a laminated film. Make molten poly on this and extrude lamin It can be formed by over preparative processing method for). These methods may be used alone or in combination.
The dry laminating method is a method in which an adhesive is applied to the surface of a film and dried, and then bonded to another film by pressure bonding. As the adhesive, a two-component curable urethane adhesive is preferable.
The extrusion sand laminating method is a method in which a resin is melted, extruded from a T-die into a thin film, and sandwiched between two films. This is an excellent method because it allows adhesion and formation of an intermediate layer at the same time. In this case as well, an adhesive layer is necessary, but since the adhesive layer can be made very thin as compared with the dry laminating method, there is an advantage that the laminated film can be formed softly. As an adhesive layer of the extrusion sand laminating method, a polyethyleneimine adhesive may be used in addition to the two-component curable urethane adhesive.

[Method for producing laminated film for highly sublimable substance]
The laminated film in the present embodiment is produced by laminating a base material layer and a heat seal layer via a predetermined adhesive layer, and then forming a coating layer on the heat seal layer by the method described above. it can.
In addition, as an adhesive agent, what is generally used for the laminated film for soft packaging is used. Specific examples include a two-component curable urethane adhesive and an ethylene-acrylic acid copolymer resin.
Moreover, in the manufacturing process of a laminated | multilayer film, it is preferable to form a film layer, after bonding a nonwoven fabric (base material layer) and a PVDC film (heat-seal layer) with a molten resin and performing extrusion lamination.
Thereby, when a laminated film is drawn out from a state wound on a roll (a state where the nonwoven fabric and the coating layer are in contact), blocking between the nonwoven fabric and the coating layer can be prevented, and workability is improved.
In addition, it is preferable to give a corona treatment to a PVDC film layer as pre-processing which apply | coats and forms a coating layer (PVDC latex).

[Packaging bags composed of laminated films for highly sublimable substances]
The packaging bag in the present embodiment is formed by heat-sealing the above-described laminated film, and the coating layer is the inner surface and the base material layer is the outer surface.
The packaging bag can be produced according to a known bag making method using a laminated film for soft packaging.
For example, there may be mentioned a method in which the film layer forming surface side of two laminated films are opposed to each other, and a bonded portion is heated and melted and pressure-bonded by heat sealing, and then cooled and solidified to be stabilized.
Examples of the heat sealing heating and pressure bonding methods include, but are not limited to, a bar sealing method, a heat roller method, a belt sealing method, an impulse sealing method, and a high frequency sealing method.
Moreover, about the form of a packaging bag, any of the well-known forms common for soft packaging may be sufficient. Specifically, a three-sided seal bag, a pillow bag, a pillow gazette bag, a four-corner seal gazette bag, and the like are exemplified, but the invention is not limited thereto.
As a method of use in the present embodiment, for example, there is a method in which a highly sublimable substance (iodine or the like) is introduced from an opening of a packaging bag and then the opening is heat sealed to form a sealed package. It is not limited to. Moreover, you may use exteriors, such as a fiber drum, a corrugated cardboard box, and a plastic or metal return box, as needed.

[Wound body composed of laminated film for highly sublimable substances]
The wound body in the present embodiment is obtained by winding the laminated film in the present embodiment described above.
The wound body in the present embodiment is composed of a laminated film having practically sufficient tear strength and tensile strength, and further, there is no stickiness between the base material layer and the coating layer, for example, a practical use process such as a packaging bag. In this manufacturing process, extremely excellent handling properties are exhibited.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples.

A method for measuring various physical properties applied in Examples and Comparative Examples described later will be described.
(1 tear strength)
The laminated films produced in the examples and comparative examples were cut into rectangles (length 75 mm, width 63 mm) to obtain test pieces.
In accordance with a method according to JIS K 7128-2, using an Elmendorf tear tester (IM-701, manufactured by Tester Sangyo Co., Ltd.), a 20 mm slit was put in the test piece, and the tear strength (mN) was measured.
(2 Tensile strength)
The laminated films produced in the examples and comparative examples were cut into a width of 15 mm according to the measurement direction to obtain test pieces.
According to a method according to JIS K 7127, the strength at break (N / 15 mm) per 15 mm width was measured using a tensile tester (Orientec Co., Ltd., RTC-1210A) under the condition of a pulling speed of 50 mm / min.
(3 puncture strength)
The laminated films produced in the examples and comparative examples were cut into squares (length 60 mm, width 60 mm) to obtain test pieces.
Using a tensile tester (Orientec Co., Ltd., RTC-1210A), the test piece was fixed, and each of the test piece surface (base material layer side) and back surface (coating layer side) had a diameter of 1.0 mm, A needle having a tip shape of 0.5 mmR was pierced at a speed of 50 mm / min, and the maximum load (N) until the needle penetrated was measured.
(4 Blocking strength)
First, the laminated films produced in Examples and Comparative Examples were cut into squares (length 120 mm, width 120 mm). Then, it cut | disconnected to length 120mmx30mm according to the magnitude | size of the testing machine, and was set as the test piece for a measurement.
Using the hydraulic heating molding machine (T-1S, manufactured by Toho Press Mfg. Co., Ltd.), the above-mentioned square test piece is superposed on the base material layer surface and the coating layer surface, and 1 at 100 kg / cm ² at a heating temperature of 60 ° C. Pressure was applied for a time to produce a laminated specimen.
This laminated test piece was fixed using a tensile tester (Orientec Co., Ltd., RTC-1210A), and the blocking strength was measured under the condition of a tensile speed of 50 mm / min.
(5 Stickiness)
The laminated films prepared in Examples and Comparative Examples were cut into squares (length 120 mm, width 120 mm) to obtain test pieces.
Using a hydraulic heating molding machine (T-1S, manufactured by Toho Press Mfg. Co., Ltd.), the base material layer surface and the coating layer surface are overlapped with each other, and the heating time is 60 ° C. and 100 kg / cm ² for 1 hour. Pressurized to prepare a laminate test piece.
The laminated test piece was peeled off with fingers to evaluate stickiness.
As an evaluation method, a sample in which the laminated test piece was smoothly peeled over the entire surface was designated as “no stickiness” 0 points. One with "stickiness" was given a point where peeling resistance was felt.
(6 Scratch resistant pinhole)
Using the films produced in the examples and comparative examples, a test three-side sealed bag having a size of 100 mm × 50 mm (outside dimension) and a seal width of 5 mm was produced.
Next, the bag was filled with water, and the bag was folded to make a corner.
Using a friction and wear tester (AB-101, manufactured by Tester Sangyo), fix it on an arm-shaped jig with a load of 200 g, and place the part into a disk with a diameter of 110 mm under the condition of a speed of 70 rpm / min. The number of friction until the pinhole was opened was measured by rubbing with the pasted cardboard.

〔Example〕
As a base material layer, a polyester-based spunbond nonwoven fabric ("ELTAS E05050 (trade name)" manufactured by Asahi Kasei Fibers Co., Ltd., having a basis weight per unit basis weight of 50 g / m ² ) was used.
As a PVDC film to be a heat seal layer, “Saran UB film (trade name), thickness 25 μm” manufactured by Asahi Kasei Chemicals Corporation was used.
A dry thickness of 0 obtained by mixing a base layer and a PVDC film with two-component curable urethane adhesive EL-510 manufactured by Toyo Ink Manufacturing Co., Ltd. and CAT-RT80 at a specified compounding ratio on each bonding surface side. The coating was performed so as to be 4 μm.
Between the base material layer and the PVDC film, “Suntech LD: L1850K (trade name)” manufactured by Asahi Kasei Chemicals Co., Ltd. was extruded so as to have a thickness of 20 μm, and bonded by a sand lamination method to form an intermediate layer.
Next, while applying a corona treatment to the PVDC film (Saran UB film) surface side which is a heat seal layer, a PVDC latex “L509” manufactured by Asahi Kasei Chemicals Co., Ltd., which is a coating layer, is applied to a dry thickness of 6 μm. Then, a drying process was performed to obtain a laminated film.

According to the test method 1 described above, the tear strength of the laminated film was measured.
The measurement results are shown in Table 1 below.
The tear strength was 3453 mN in the film flow direction (hereinafter referred to as the MD direction) and 4895 mN in the width direction (hereinafter referred to as the TD direction), indicating a practically sufficient strength.

According to the test method 2 described above, the tensile strength of the laminated film was measured.
The measurement results are shown in Table 1 below.
The tensile strength was 113 N / 15 mm width in the MD direction and 80 N / 15 mm width in the TD direction, indicating a practically sufficient strength.

According to the test method 3 described above, the puncture strength of the laminated film was measured.
The measurement results are shown in Table 1 below.
In addition, since evaluation of puncture strength is performed with respect to each of the front surface and the back surface of a test piece as shown in the test method 3 above, in Table 1, the measurement surface and the measurement result are shown in parentheses. And differentiated from other tests.
The front side (base material: non-woven fabric) was 15N, and the back side (coating layer: PVDC) was 19N, showing practically sufficient strength.

According to Test Method 4 described above, the blocking strength of the laminated film was measured.
The measurement results are shown in Table 1 below.
The MD direction was 0.07 N / 30 mm width and the TD direction was 0.08 N / 30 mm width, which were practically small values.

According to the test method 5 mentioned above, the stickiness of the laminated film was evaluated.
The evaluation results are shown in Table 1 below.
When the test piece on which the base material surface and the coating layer (vinylidene latex layer) surface were overlapped was peeled off with fingers, no stickiness was felt in all the test pieces out of the total of 10 test pieces.

According to the test method 6 described above, the rubbing resistance pinhole of the laminated film was measured.
The measurement results are shown in Table 2 below.
The number of times until a pinhole was generated by rubbing against the cardboard was 984 times, and had practically sufficient slidability.

[Comparative Example]
As the base material layer, a biaxially stretched nylon film “general type (trade name), (thickness: 15 μm)” manufactured by Unitika Ltd. was used.
As a PVDC film to be a heat seal layer, “Saran UB film (trade name)” (thickness 15 μm) manufactured by Asahi Kasei Chemicals Corporation was used.
A mixture of a base layer and a PVDC film on which the two-part curable urethane adhesives EL-510 and CAT-RT80 manufactured by Toyo Ink Manufacturing Co., Ltd. were mixed at a specified blending ratio was dried to a thickness of 0. Coating was performed so as to be 4 μm.
Between the base material layer and the PVDC film, “Suntech LD: L1850K (trade name)” manufactured by Asahi Kasei Chemicals Co., Ltd. was bonded by an extrusion sand laminating method so as to have a thickness of 30 μm.
Next, while applying a corona treatment to the PVDC film (Saran UB film) surface side which is a heat seal layer, a PVDC latex “L509” manufactured by Asahi Kasei Chemicals Co., Ltd., which is a coating layer, is applied to a dry thickness of 6 μm. Then, a drying process was performed to obtain a laminated film.

According to the test method 1 described above, the tear strength of the laminated film was measured.
The measurement results are shown in Table 1 below.
The tear strength was 392 mN in the MD direction and 323 mN in the TD direction, indicating very low strength.

According to the test method 2 described above, the tensile strength of the laminated film was measured.
The measurement results are shown in Table 1 below.
The tensile strength was 76 N / 15 mm width in the MD direction and 72 N / 15 mm width in the TD direction, indicating a small strength.

According to the test method 3 described above, the puncture strength of the laminated film was measured.
The measurement results are shown in Table 1 below.
The front side (base material side) was 10N and the back side (coating layer: PVDC side) was 12N, which was practically insufficient strength.

According to Test Method 4 described above, the blocking strength of the laminated film was measured.
The measurement results are shown in Table 1 below.
The MD direction was 0.13 N / 30 mm width and the TD direction was 0.12 N / 30 mm width, resulting in large values due to blocking, and practically good characteristics could not be obtained.

According to the test method 5 mentioned above, the stickiness of the laminated film was evaluated.
The evaluation results are shown in Table 1 below.
When the test piece on which the base material surface and the coating layer (vinylidene latex layer) surface were overlapped was peeled off with fingers, stickiness was felt in all of the 10 test pieces.

According to the test method 6 described above, the rubbing resistance pinhole of the laminated film was measured.
The measurement results are shown in Table 2 below.
The number of times until pinholes were rubbed against the cardboard was 497 times, and practically sufficient slidability resistance was not obtained.

  Since the laminated film of the present invention has sufficient heat seal strength, for example, a highly sublimable substance such as iodine, a substance having high permeability and easily changing various materials, alcohols, organic solvents, There is industrial applicability as a packaging material for transporting and storing chemicals.

Claims (4)

A heat seal layer and a coating layer are sequentially laminated on the base material layer,
The base material layer is made of a nonwoven fabric,
The heat seal layer is made of a stretched film made of polyvinylidene chloride,
The coating layer is a laminated film for highly sublimable substances made of polyvinylidene chloride latex. A packaging bag formed by heat sealing the laminated film for highly sublimable substances according to claim 1,
A packaging bag for a highly sublimable substance, wherein the coating layer is an inner surface and the base material layer is an outer surface.   A laminated film roll for a highly sublimable substance, on which the laminated film for a highly sublimable substance according to claim 1 is wound. A step of laminating a heat seal layer made of a stretched film made of polyvinylidene chloride on a base material layer made of a nonwoven fabric,
And a step of laminating a film layer made of polyvinylidene chloride latex on the heat seal layer.