TW202035542A - Resin film and method for manufacturing same - Google Patents

Abstract

An objective of the present invention is to provide a resin film, an end of which can easily be released from a wound section in a wound-back state without tearing the resin film in the longitudinal direction. In order to achieve this objective, a resin film according to the present invention is formed from a vinylidene chloride resin composition in which the ratio (surface adhesive strength value/MD tear strength value) of the value for surface adhesive strength (unit: N) to the value for MD tear strength (unit: mN) is at least 0.35 and less than 0.41.

Description

Resin film and its manufacturing method

The present invention relates to a resin film and its manufacturing method.

Vinylidene chloride-based resin films are widely used as packaging films because they are difficult to penetrate oxygen and moisture, have high adhesion, high heat resistance, and high transparency.

The packaging film is usually contained in the storage box in the form of a roll wound into a roll. As the aforementioned storage box, there is known a storage box that has a main body portion that stores the winding body, and a cover portion rotatably connected to the main body portion. The user of the packaging film holds the end of the packaging film contained in the main body, while rotating the winding body, pulls the aforementioned end, and draws out the amount of packaging film to be used from the gap between the main body and the cover, and The cutting blade provided on the lid is used for cutting, so that the packaging film of the required length can be taken out of the storage box. At this time, in order to facilitate the next extraction, the end of the cut wound body should be attached to the main body and locked.

The aforementioned vinylidene chloride-based resin film is produced by melt-extruding a vinylidene chloride-based resin composition obtained by a method such as suspension polymerization, and then stretched in a film shape.

Patent Document 1 describes that by using a suspension dispersant during the aforementioned suspension polymerization, the suspension stability can be improved, or the particle size of the obtained vinylidene chloride resin can be controlled to improve the extrusion stability and uniform thickness of the film. Sex. Patent Document 1 describes that by using a suspending agent of 500 ppm for 100 parts by mass of the monomer used to synthesize the vinylidene chloride resin, a film can be produced well.

Patent Document 2 describes that by adding liquid paraffin to a polyvinylidene chloride-based film, the film can exhibit proper peeling performance. Known technical literature Patent literature

Patent Document 1: International Publication No. 2003/006548 Patent Document 2: Japanese Patent Laid-Open No. 10-087876

Problems to be solved by the invention However, the packaging film contained in the aforementioned storage box in the form of a wound body may have the following situation: the end cut by the reverse rotation of the wound body, etc., is rolled back to the inside of the main body, causing the aforementioned end to be attached On the surface of the wound packaging film (hereinafter also referred to as "winding part") (hereinafter, the state where the end of the packaging film is attached to the surface of the winding part due to rewinding is also referred to as "rewinding state") . Here, since high adhesiveness is required for packaging films, the adhesiveness between packaging films is also very high. Therefore, if you want to peel off the end of the aforementioned attachment from the winding part and restore it to the state where the end part is peeled from the winding part, you need to grasp the end of the packaging film and pull it outward with great force. The force of the end is prone to tearing of the packaging film in the MD. If it is desired to restore the packaging film in a manner that does not cause the aforementioned longitudinal tearing, it takes time to restore.

On the other hand, as described in Patent Document 2, when liquid paraffin is also considered to improve the releasability of a resin film used as a packaging film, the packaging film can be easily restored from a rolled state. However, according to the findings of the inventors, it is desired to reduce the amount of liquid paraffin due to the strengthening of regulations in recent years. If this is the case, the peelability of the resin film cannot be sufficiently improved, and the longitudinal tearing of the resin film during recovery cannot be sufficiently suppressed. crack.

In view of the foregoing problems, an object of the present invention is to provide a resin film that can easily peel the end portion from the wound portion in the rewind state without tearing the resin film in the longitudinal direction, and a method of manufacturing such a resin film. Technical means to solve the problem

The resin film of one aspect of the present invention for solving the aforementioned problems is a resin film containing a vinylidene chloride-based resin composition, and the value of the surface adhesion (N) is relative to the value of the tearing strength to MD (mN The ratio of) (the value of surface adhesion/the value of tearing strength to MD) is 0.35 or more and less than 0.41.

In addition, a method for manufacturing a resin film according to another aspect of the present invention for solving the aforementioned problems includes: stretching the melted and extruded vinylidene chloride resin composition; and stretching the aforementioned stretched vinylidene chloride The step of relaxing the vinyl resin composition. The aforementioned vinylidene chloride-based resin composition system will be used to synthesize vinylidene chloride-based resin by polymerization. The monomer content relative to the total mass of the aforementioned monomers is a water-soluble fiber with a content of 300 ppm or more and 600 ppm or less A resin composition obtained by suspension polymerization in an aqueous medium in the presence of a prime derivative. In the aforementioned manufacturing method, in the aforementioned stretching step, the vinylidene chloride resin composition has a stretching ratio of 3.5 times or more and 5.0 times in MD, and a stretching ratio of 4.0 times or more and 5.5 times in TD. In the aforementioned relaxation step, the aforementioned stretched vinylidene chloride resin composition is relaxed so that the relaxation rate to MD is 9.5% or more and 12.5% or less. Invention effect

According to the present invention, there is provided a resin film whose end is easily peeled from a wound portion in a rewind state without tearing the resin film in the longitudinal direction, and a method of manufacturing such a resin film.

[Resin Film] (Physical properties, etc.) One embodiment of the present invention relates to a resin film containing a vinylidene chloride resin composition. The ratio of the value of the surface adhesion force (unit: N) of the aforementioned resin film to the value of the tearing strength (unit: mN) to the MD (the value of the surface adhesion force (N)/the value of the tearing strength to the MD ( mN). Hereinafter, this ratio is also simply referred to as "recovery coefficient") of 0.35 or more and less than 0.41.

In addition, the term “MD” refers to the winding direction of the resin film wound into a roll. Moreover, the so-called TD refers to the direction orthogonal to MD in the plane of the resin film.

In order to facilitate the recovery of the resin film containing the vinylidene chloride resin composition from the wound portion in the rewind state without tearing the resin film in the longitudinal direction, the value of the aforementioned surface adhesion force is desirably lower. The tear strength is ideally higher. However, in order to sufficiently ensure the adhesion of the resin film to the container, etc., it is not desirable to make the aforementioned surface adhesion force too low.

From these viewpoints, in the present embodiment, the aforementioned restoration coefficient is set to be 0.35 or more and less than 0.41. If the aforementioned coefficient of restitution is 0.35 or more, the surface adhesion of the resin film will not decrease excessively, and the adhesion to the container can be fully ensured. On the other hand, if the aforementioned coefficient of restitution is less than 0.41, the tearing strength of the resin film to MD is appropriately increased, and the surface adhesion force is appropriately reduced, so it is easy to restore the resin film in a rolled state without tearing in the longitudinal direction. From the aforementioned viewpoint, the aforementioned coefficient of restitution is preferably 0.36 or more and 0.40 or less, more preferably 0.37 or more and 0.40 or less.

The value of the aforementioned tear strength to MD can be set to a value measured using a known tear tester. Specifically, a test piece obtained by cutting the resin film into a size of 63.5 mm in the length direction (MD) × 50 mm in the width direction (TD) is set in the center of the splint of the tear tester, so that the length direction (MD) When the incision length becomes 12.7 mm, a knife is used to cut the incision in the center of the width direction (TD) of the test piece, and the pendulum is released to cut the test piece. The maximum load for cutting the test piece at this time can be set as the value of the tearing strength of the test piece to MD (unit: mN).

The aforementioned surface adhesion force can be set to a value measured using a known tensile tester. Specifically, on the bottom surface of each of two aluminum cylindrical jigs with a bottom area of 25 cm ² and a mass of 300 g, the resin film is tightened and fixed in a manner that does not produce wrinkles, so that the resin film is fixed to the two jigs They are in contact with each other in the vertical direction and crimped. Then, use a tensile testing machine to pull the two jigs in opposite vertical directions. The maximum load (unit: N) used to open the fixture at this time can be set as the value of the surface adhesion force of the test piece.

In addition, from the viewpoint of easy adjustment of the aforementioned coefficient of restitution to the aforementioned range, the value of the tearing strength to MD of the aforementioned resin film is preferably 32.0 mN or more and 34.5 mN or less, more preferably 32.5 mN or more and 34.5 mN Hereinafter, it is more preferably 33.0 mN or more and 34.5 mN or less. In addition, if the value of the aforementioned tearing strength to MD is 32.0 mN or more, the resin film is unlikely to be cracked in the longitudinal direction during restoration and other uses, so the ease of use of the resin film can be further improved.

In addition, from the viewpoint of easy adjustment of the coefficient of restitution to the aforementioned range, the surface adhesion value of the resin film is preferably 12.0N or more and 13.0N or less, more preferably 12.0N or more and 12.5N or less. If the value of the aforementioned surface adhesion force is 12.0N or more, the resin film will easily adhere to the container etc. during use, so the ease of use of the resin film can be further improved.

In addition, as described later, in this embodiment, a vinylidene chloride resin composition containing a vinylidene chloride resin polymerized in the presence of a predetermined amount of a water-soluble cellulose derivative is stretched at a predetermined ratio and Relaxation can be used to make a resin film that satisfies the aforementioned coefficient of restitution. From the viewpoint of suppressing the decrease in the transparency of the resin film caused by the water-soluble cellulose derivative used, the haze value of the aforementioned resin film is preferably 1.2% or less, more preferably 0.8% or less, and further Preferably it is 0.6% or less. In addition, although the lower limit of the haze value is not specifically defined, it can be set to 0.05% or more.

The aforementioned haze value can be set to a value measured in accordance with JIS K 7136 (2000).

In addition, from the viewpoint of further improving the transparency of the resin film, the arithmetic mean surface roughness (Ra) specified by JIS B 0601 (2013) of the aforementioned resin film is preferably greater than 5.0 nm and less than 20.0 nm, and more It is preferably greater than 5.0 nm and 7.7 nm or less, and more preferably greater than 6.0 nm and less than 7.5 nm.

The aforementioned arithmetic surface roughness (Ra) can be set to a value obtained by using a known surface roughness measuring device.

In addition, in this embodiment as described later, by stretching the vinylidene chloride-based resin composition at a higher magnification than before, a resin film satisfying the aforementioned value of the coefficient of recovery can be produced. Therefore, in the resin film of the present embodiment, the molecules of the vinylidene chloride-based resin are aligned in the MD in a state of further tension, the piercing of the dicing blade, etc. is easier, and the cutting (especially cutting to the TD) is easier. Specifically, the value of the puncture strength of the aforementioned resin film is preferably less than 4.0N, more preferably less than 3.8N, and still more preferably less than 3.5N. In addition, although the lower limit of the puncture strength is not specifically defined, it can be 1.5N or more from the viewpoint of easy maintenance of the shape of the resin film.

The aforementioned puncture strength can be set to a value measured in accordance with JIS Z 1707 (2019).

The thickness of the aforementioned resin film is not particularly limited, and can be 1 µm or more and 50 µm or less, preferably 4 µm or more and 45 µm or less, and more preferably 7 µm or more and 40 µm or less. If the aforementioned thickness is 1 µm or more, the aforementioned resin film can be made difficult to break. If the aforementioned thickness is 50 µm or less, the cutability of the aforementioned resin film becomes good, and the film feels good.

The aforementioned resin film may be a transparent resin film. In addition, the aforementioned resin film has adhesiveness to food, tableware, and the like. Therefore, the aforementioned resin film can be suitably used as a packaging film.

In addition, the aforementioned resin film is preferably stored in the form of a roll wound into a roll. The rolling body is preferably accommodated in a storage box having a main body for accommodating the rolling body, a cover rotatably connected to the main body, and a cutting blade on the cover. The wound body contained in the storage box can be used to draw out the amount of resin film to be used from the gap between the main body and the lid by rotating the wound body while pulling the end of the resin film, and use the The cutting blade of the cover cuts, and only the required length is taken out from the storage box. (Composition etc.)

The aforementioned resin film is a single-layer film formed by molding a vinylidene chloride-based resin composition into a film shape.

The aforementioned vinylidene chloride-based resin composition is a resin composition containing a vinylidene chloride-based resin as a main component.

The aforementioned vinylidene chloride-based resin may be a homopolymer of vinylidene chloride or a copolymer containing structural units derived from vinylidene chloride.

The aforementioned copolymer is a copolymer of vinylidene chloride and a monomer copolymerizable with vinylidene chloride. Examples of monomers copolymerizable with the aforementioned vinylidene chloride include: vinyl chloride; including methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate and stearyl acrylate, etc. Alkyl acrylates with a carbon number of 1 or more and 18 or less; including methyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate and ten methacrylate Alkyl methacrylates, such as octaesters, whose alkyl group has a carbon number of 1 to 18; vinyl cyanide compounds including acrylonitrile and methacrylonitrile; aromatic vinyl compounds including styrene; including vinyl acetate Vinyl esters of aliphatic carboxylic acids with a carbon number of 1 or more and 18 or less; alkyl vinyl ethers with a carbon number of 1 or more and 18 or less; including acrylic acid, methacrylic acid, maleic acid, trans Ethylene polymerizable unsaturated carboxylic acid such as butenedioic acid and methylene succinic acid; Alkyl group of ethylene polymerizable unsaturated carboxylic acid such as maleic acid, fumaric acid and methylene succinic acid Alkyl esters with 1 to 18 carbon atoms (partial esters may also be used); and diene monomers, etc. Among them, vinyl chloride, methyl acrylate and butyl acrylate are preferred, and vinyl chloride is more preferred.

The ratio of the vinylidene chloride-derived structural unit of the aforementioned copolymer to the total mass is preferably 60% by weight or more, more preferably 70% by weight or more, and still more preferably 80% by weight or more. Although the upper limit of the ratio of the aforementioned vinylidene chloride-derived structural unit is not particularly specified, from the viewpoint of improving extrusion processability, etc., it is preferably 98% by weight or less, and more preferably 95% by weight or less.

The reduction viscosity of the vinylidene chloride resin is preferably 0.035 or more and 0.070 or less, and more preferably 0.040 or more and 0.065 or less. If the reduction viscosity is 0.035 or more, the extrusion processability of the vinylidene chloride resin composition can be further improved. If the aforementioned reduction viscosity is 0.70 or less, the coloration of the resin film is suppressed, and the vinylidene chloride-based resin composition can be more easily melted during molding.

From the viewpoint of further improving the extrusion processability, the aforementioned vinylidene chloride resin composition may further contain ethylene-vinyl acetate copolymer, copolymerization of ethylene and acrylic acid, methacrylic acid, or alkyl esters of these And other resins such as MBS resin (methyl methacrylate-butadiene-styrene copolymer). The content of the other resin is preferably 0.1 part by mass or more and 20 parts by mass or less, and more preferably 1.0 part by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the vinylidene chloride-based resin.

The vinylidene chloride resin composition may also contain a water-soluble cellulose derivative when synthesizing the vinylidene chloride resin by suspension polymerization. The aforementioned water-soluble cellulose derivative not only functions as a suspending agent during suspension polymerization, but also remains on the surface of the resin film to appropriately roughen the surface of the resin film.

Examples of the aforementioned water-soluble cellulose derivatives include methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropoxymethyl cellulose, and carboxymethyl cellulose, etc. . Among them, methyl cellulose, hydroxypropyl cellulose, and hydroxypropoxymethyl cellulose are more preferred, and methyl cellulose is still more preferred.

The aforementioned water-soluble cellulose derivative is preferably contained in such an amount that when the resin film is immersed in 100 ml of ethanol, heated to 70°C and extracted for 5 hours, 15 µg or more is extracted per 1 m ² . If the extraction amount of the water-soluble cellulose derivative under the aforementioned conditions is within the aforementioned range, it is estimated that the aforementioned water-soluble cellulose derivative will moderately remain on the surface of the resin film, so that the surface of the resin film is appropriately roughened, thereby maintaining approximately The tearing strength of the resin film to MD, and the surface adhesion is moderately reduced. Therefore, it is easy to adjust the aforementioned restoration coefficient to the aforementioned range. Although the upper limit of the content of the aforementioned water-soluble cellulose derivative extracted from the resin film is not particularly limited, it can be set to 100 µg or less per 1 m ^{2 of the} resin film, preferably 50 µg or less, and more preferably 30 µg the following.

The aforementioned vinylidene chloride-based resin composition may also contain additives such as plasticizers, stabilizers, and lubricants within a range that does not significantly affect the aforementioned coefficient of recovery.

Examples of the aforementioned plasticizers include tributyl acetyl citrate, dioctyl phthalate, dibutyl sebacate, dioctyl sebacate, diacetylated monoglyceride, acetylated Diglycerides and acetylated triglycerides, etc. Examples of the aforementioned stabilizers include epoxidized soybean oil (ESBO) and epoxidized linseed oil (ELO). The total content of the plasticizer and stabilizer is preferably 0.5 parts by mass or more and 10 parts by mass or less, and more preferably 1.0 parts by mass or more and 7.0 parts by weight relative to 100 parts by mass of the vinylidene chloride resin .

Examples of the aforementioned luster agent include saturated fatty amides, unsaturated fatty amides, substituted amides, and thioether compounds. The content of the luster agent is preferably 0.05 parts by mass or more and 10 parts by mass or less, and more preferably 0.1 parts by mass or more and 6.0 parts by weight relative to 100 parts by mass of the vinylidene chloride-based resin.

In addition, the aforementioned vinylidene chloride-based resin composition may contain a tackifier.

Examples of the aforementioned thickeners include sorbitan fatty acid esters such as sorbitan monooleate and sorbitan trioleate, propylene glycol fatty acid esters, glycerin such as glycerol monooleate and glycerol trioleate Fatty acid esters, and liquid paraffin, etc.

However, the aforementioned vinylidene chloride resin composition preferably does not substantially contain a thickener. The term "substantially not containing" means that the content of the tackifier is 100 ppm or less (preferably 50 ppm or less, more preferably 20 ppm or less) relative to 100 parts by mass of the vinylidene chloride resin. [Manufacturing method of resin film]

The aforementioned resin film can be produced by a method including a step of stretching the melted and extruded vinylidene chloride-based resin composition and a step of relaxing the stretched vinylidene chloride-based resin composition . (Preparation of vinylidene chloride resin composition)

The aforementioned vinylidene chloride resin composition can be prepared by mixing the synthesized vinylidene chloride resin and various additives.

The vinylidene chloride resin can be synthesized by suspension polymerization of vinylidene chloride and monomers copolymerizable with the vinylidene chloride.

Specifically, in a reactor (polymerizer) made of stainless steel, etc., vinylidene chloride (vinylidene chloride and a monomer that can be copolymerized with the vinylidene chloride in the synthesis of the copolymer) are placed in the water-soluble fiber In the presence of the element derivative, it is stirred in an aqueous medium to suspend and disperse into oil droplets. Then, a polymerization initiator is added to the aforementioned suspension, and the temperature is raised as necessary to polymerize vinylidene chloride (and monomers copolymerizable with the aforementioned vinylidene chloride). The temperature at this time is usually 25 to 90°C, preferably 30 to 85°C, and the polymerization time is usually 1 to 100 hours, preferably 2 to 60 hours, and more preferably 3 to 50 hours.

At this time, the addition amount of the aforementioned water-soluble cellulose derivative relative to 100 parts by mass of vinylidene chloride (and the monomer copolymerizable with the aforementioned vinylidene chloride) is set to 300 ppm or more and 600 ppm or less. The best setting is 300 ppm or more and 500 ppm or less. By setting the amount of the water-soluble cellulose derivative in the aforementioned range, it is estimated that the aforementioned water-soluble cellulose derivative remaining on the surface of the resin film will make the surface of the resin film moderately rough, thereby substantially maintaining the produced resin The tear strength of the film to MD, and the surface adhesion is moderately reduced. Therefore, it is easy to adjust the aforementioned recovery coefficient of the produced resin film to the aforementioned range.

The obtained vinylidene chloride-based resin is mixed with additives such as plasticizers, stabilizers, and lubricants contained in the resin film as necessary to prepare the aforementioned vinylidene chloride-based resin composition. In addition, the aforementioned additives can be mixed at any point in time, and can be added to the suspension during polymerization, or the vinylidene chloride resin can be mixed with the aforementioned additives after the polymerization. The mixing can be carried out using the following well-known mixing devices: Henschel mixer, cylindrical mixer, screw mixer, screw extruder, Turbulizer, conical screw mixer (Nauta mixer) , V-type mixer, belt type mixer, double-arm type kneader, flow type mixer, air-flow type mixer, rotating disc type mixer, roller mixer, rolling mixer and Laudige mixer ( Lodige mixer) and so on. Thereby, a vinylidene chloride resin composition in powder or pellet form can be obtained. (Forming of resin film)

The vinylidene chloride resin composition prepared as described above is stretched and relaxed after being melted and extruded by a known method.

First, the aforementioned vinylidene chloride-based resin composition is put into an extruder, melted in a cylinder, and extruded from a die. The die may be a T-die for extruding the vinylidene chloride resin composition in a flat shape, or a ring die (circular) for extruding the vinylidene chloride resin composition in a tubular shape. Die head).

The aforementioned extruded vinylidene chloride-based resin composition passes through a plurality of guide rollers and a plurality of nip rollers, and is then wound by a winding roller. At this time, by varying the rotation speeds of the continuous nip rolls among the plurality of nip rolls, or by adjusting the amount of air used to inflate the vinylidene chloride resin composition extruded in a tubular shape, the extrusion can be achieved The vinylidene chloride-based resin composition extends in the MD (direction of travel) at a predetermined ratio. In addition, by using a tenter or adjusting the amount of air when the vinylidene chloride resin composition extruded in a tubular shape is inflated, the extruded vinylidene chloride resin composition can be made at a predetermined ratio Extend to TD (the direction orthogonal to the direction of travel). Then, the vinylidene chloride-based resin composition stretched in MD and TD relaxes in MD due to the difference in the rotation speed of subsequent continuous nip rolls.

In this embodiment, it is possible to adjust the surface adhesion (recovery coefficient) of the molded resin film with respect to the value of the tearing strength to MD by the stretching ratio in MD and TD and the relaxation ratio in MD at this time .

Specifically, at this time, the stretching ratio in MD is set to 3.5 times or more and 5.0 times or less, the stretching ratio in TD is set to 4.0 times or more and 5.5 times or less, and the relaxation rate in MD is set to 9.5% or more and 12.5%.

The aforementioned stretching ratio in MD is more preferably 3.5 times or more and 4.5 times or less, and still more preferably 3.8 times or more and 4.5 times or less. The aforementioned stretching ratio to TD is more preferably 4.5 times or more and 5.5 times or less, and still more preferably 4.5 times or more and 5.0 times or less. The aforementioned relaxation rate in MD is more preferably 10.5% or more and 12.0% or less, and still more preferably 11.0% or more and 12.0% or less.

By increasing the stretching ratio in this way, and also increasing the subsequent relaxation rate, the molecules of the vinylidene chloride resin can be easily aligned in the MD in a further tensioned state, and the tearing strength of the resin film to the MD can be appropriately increased. Relaxation makes the surface of the resin film moderately rough and moderately reduces the surface adhesion. In addition, in this embodiment, since the vinylidene chloride-based resin composition contains a water-soluble cellulose derivative, the surface of the resin film is also appropriately roughened, and the surface adhesion force is appropriately reduced. It is believed that under these effects, a resin film with a coefficient of restitution of 0.35 or more and less than 0.41 can be obtained, the resin film does not tear in the longitudinal direction, and the end portion is easily peeled from the wound portion in the rewind state.

Then, the stretched and relaxed vinylidene chloride resin composition is wound up by a winding roller.

In addition, the aforementioned vinylidene chloride resin composition extruded in a tube shape using a tubular die can be cut along the extrusion axis to form a single-layer thickness flat film, or folded to form a double-layer thickness Flat film. Example

Hereinafter, the present invention will be explained more specifically with reference to examples, but the scope of the present invention is not limited to the description of the examples. 1. Production of resin film 1-1. Production of resin film-1

Mix vinylidene chloride (VD) and vinyl chloride (VC) at VD:VC=82:18 (mass ratio), and then add methyl cellulose-dissolved water and tributyl acetyl citrate as an additive (ATBC), diacetylated monoglyceride (DALG) and epoxidized soybean oil to prepare additional raw materials. The content of methylcellulose in the added raw material is adjusted to 403 ppm relative to the total amount of the mass of VD and the mass of VC. The amount of the aforementioned additives in the added raw materials was adjusted so that the total amount of the additives was 8.3 parts by mass relative to 100 parts by mass of the synthesized vinylidene chloride-vinyl chloride copolymer. Using this additive raw material, a vinylidene chloride-based resin composition containing a vinylidene chloride-vinyl chloride copolymer is prepared by a suspension polymerization method.

The vinylidene chloride resin composition was melt-extruded from a ring die at 185°C using a single-screw extruder, and the resulting tubular parison was quenched with water, and then heated to around room temperature in a warm water bath. After that, the stretch magnification of 4.1 times in the longitudinal direction (MD) and 4.7 times in the transverse direction (TD) is carried out for inflation and biaxial stretching, and the longitudinal direction (MD) is 11% of the relaxation rate to the MD after relaxation, and then the winding roller is used. take. Perform slitting and rewinding of the wound film to obtain a wound resin film-1 with a thickness of 10 µm, a width of 30 cm, and a length of 50 m. 1-2. Production of resin film-2 Production of resin film-2

Except that the relaxation rate in the longitudinal direction (MD) when the vinylidene chloride-based resin composition is formed into a thin film is set to 12%, the resin film as a wound body is obtained in the same manner as in the production of the resin film-1- 2. 1-3. Production of resin film-3

Except that the relaxation rate in the longitudinal direction (MD) when the vinylidene chloride resin composition is made into a thin film is set to 9%, the resin film as a wound body is obtained in the same manner as the production of the resin film-1- 3. 1-4. Production of resin film-4

The amount of methyl cellulose added in the raw materials used in the synthesis of the vinylidene chloride resin composition is set to 250 ppm relative to the total amount of the mass of VD and the mass of VC, and the resulting vinylidene chloride Except that the relaxation rate in the longitudinal direction (MD) when the ethylene resin composition was formed into a thin film was set to 9%, the resin film-4 as a wound body was obtained in the same manner as the production of the resin film-1. 1-5. Production of resin film-5

In addition to the raw materials used in the synthesis of the vinylidene chloride resin composition, liquid paraffin as a tackifier is added in an amount of 782 ppm relative to the total amount of the mass of VD and the mass of VC. In addition, The resin film-5 as a wound body was obtained in the same manner as the production of the resin film-4. 1-6. Production of resin film-6

In addition to the raw materials used in the synthesis of the vinylidene chloride resin composition, liquid paraffin in an amount of 782 ppm relative to the total amount of the mass of VD and the mass of VC is added to make the obtained vinylidene chloride resin composition. When the resin composition is formed into a thin film, the stretching ratio in the longitudinal direction (MD) is set to 3.2 times, the stretching ratio in the transverse direction (TD) is set to 5.4 times, and the relaxation rate in the longitudinal direction (MD) is set to 10%. In the same manner as in the production of film-1, a resin film-6 as a wound body was obtained. 1-7. Production of resin film-7

The amount of methylcellulose added in the raw materials used in the synthesis of the vinylidene chloride resin composition is set to 755 ppm relative to the total amount of the mass of VD and the mass of VC, and the resulting vinylidene chloride Except that the relaxation rate in the longitudinal direction (MD) when the ethylene-based resin composition was formed into a thin film was set to 9%, the resin film-7 as a wound body was obtained in the same manner as the production of the resin film-1.

The amount of additives (water-soluble cellulose derivatives and tackifiers) to be used in the production of resin film-1~resin film-7, and the manufacturing conditions (longitudinal (MD) stretch ratio, transverse (TD) stretch ratio , And longitudinal (MD) relaxation rate) are shown in Table 1.

[Table 1] Resin film No. 1 2 3 4 5 6 7 additive Water-soluble cellulose derivatives (ppm) 403 403 403 250 250 403 755 Tackifier (ppm) - - - - 782 782 - Manufacturing conditions Stretching ratio (MD) (Times) 4.1 4.1 4.1 4.1 4.1 3.2 4.1 Stretching ratio (TD) (Times) 4.7 4.7 4.7 4.7 4.7 5.4 4.7 (Relaxation rate) (MD) (%) 11 12 9 9 9 10 9 2. Evaluation 2-1. Extraction amount of water-soluble cellulose derivatives

Pull out the resin film-1~resin film-7 of sufficient length from the winding body and cut it to make a test piece.

The test piece was immersed in 100 ml of ethanol, heated to 70°C, and extracted for 5 hours. Then, the extract is dried and solidified to obtain an ethanol extract. The aforementioned ethanol extract was dissolved in a 15% ethanol aqueous solution and washed with carbon disulfide. After washing, the water phase is dried and solidified, hydroiodic acid (HI) is allowed to react, and the generated methyl iodide is dissolved in o-xylene.

Analyze the aforementioned o-xylene layer in which methyl iodide is dissolved by gas chromatography (GC), and convert the amount of methyl iodide into methyl cellulose to obtain methyl cellulose eluted from the surface of the resin film the amount. Divide the obtained amount of methyl cellulose by the area of the resin film (unit: m ² ), and set it as the amount of water-soluble cellulose derivative present on the surface of the resin film (unit: µg/m ² ).

GC is performed under the following equipment and conditions. (Measurement equipment･Column) GC-FID: GL sciences GC-4000 Plus column: Agilent J&W GC columns DB-624 (length: 30m, inner diameter: 0.530 mm, film thickness: 3.00 µm) (GC conditions) column Temperature: 60°C (hold for 5 minutes) → heating up 20°C/min→210°C (hold for 5 minutes) Note inlet temperature: 230°C detector temperature: 230°C Carrier gas: N ₂ (tube flow rate 4.2 ml/min) injection Method: Split ratio (5:1) Injection volume: 1 µl 2-2. Surface adhesion

Pull out each of Resin Film-1~Resin Film-7 from the wound body, and cut them into a size of 200~300 mm in the length direction (MD) × 300 mm in the width direction (TD) to prepare a test piece.

Prepare two aluminum cylindrical jigs with a base area of 25 cm ² and a mass of 300 g. On the bottom surface of one of the jigs, tighten and fix each test piece in a manner that does not produce wrinkles. On the bottom surface of another jig, the test piece obtained from the same resin film is also tightened and fixed in a manner that does not produce wrinkles. The two jigs are brought into contact in the vertical direction so that the bottom surfaces of the fixed test pieces are completely overlapped with each other, and the test pieces are pressed against each other by pressing with the weight of the jig on the upper side of the vertical for 1 minute. Then, using the Tensilon RTC-1210A tensile and compression testing machine manufactured by ORIENTEC Co., Ltd., pull the two jigs in the opposite direction (vertical direction) at a speed of 100 mm/min. They will be used for pulling apart treatment. The maximum load (unit: N) of the (test piece) is used as the surface peel strength of the test piece. The measurement was performed in an environment of 23° C. and 50% RH, and the average value of the surface peel strength obtained for the five test pieces was taken as the surface adhesion force of the resin film. 2-3. Tear strength to MD

Pull out each of Resin Film-1~Resin Film-7 from the wound body, and cut them into a size of 63.5 mm in the length direction (MD) × 50 mm in the width direction (TD) to prepare a test piece.

Using a light-load tear tester No. 193 model D manufactured by Toyo Seiki Seisakusho Co., Ltd., and the measurement range was set to 196 mN, the tear strength of each test piece to MD was determined. After setting the test piece in the center of the splint, use a knife to cut the incision in the center of the test piece in the width direction (TD) so that the length of the cut in the longitudinal direction (MD) becomes 12.7 mm, release the pendulum, and measure for the cut test The maximum load of the film (unit: mN). The measurement was performed in an environment of 23° C. and 50% RH, and the average value of the tearing strength to MD of the five test pieces was taken as the tearing strength of the resin film to MD. 2-4. Haze value

Pull out the resin film-1~resin film-7 of sufficient length from the winding body and cut it to make a test piece.

Using a haze meter NDH7000SP manufactured by Nippon Denshoku Industries Co., Ltd., the haze value (unit: %) of each test piece was measured in accordance with JIS K 7136 (2000). The average value of the haze values obtained for the five test pieces is taken as the haze value of the resin film. 2-5. Puncture strength

Pull out the resin film-1~resin film-7 of sufficient length from the winding body and cut it to make a test piece.

A tensile testing machine TENSILON RTG-1210 manufactured by A&D Co., Ltd. was used to measure the puncture strength (unit: N) of each test piece in accordance with JIS Z 1707 (2019). The measurement was performed in an environment of 23° C. and 50% RH, and the average value of the puncture strength obtained for the five test pieces was taken as the puncture strength of the resin film. 2-6. Recovery time

Put each of Resin Film-1~Resin Film-7 in a containment box (Kureha Co., Ltd., Kure Wrap containment box), pull out 30 cm from the containment box, and leave it in a blade shape with the lid closed. Cut each resin film by resin film method. After that, the remaining resin film is rolled back into the container in a manner that does not produce wrinkles as much as possible, and the end of the resin film is adhered to the wound resin film.

From this state, 40 people including male and female evaluators were asked to pull out the entire width of the resin film to the outside of the storage box without using tape or other tools to prevent longitudinal cracks. After the evaluator finds out the end of the resin film adhered to the wound resin film until the entire width of the resin film is pulled out to the outside of the containing box, the time is set as the recovery time. The measurement was performed in an environment of 23°C and 50% RH, and the average value of the recovery time obtained in the five tests was taken as the recovery time of the resin film.

The ratio of the aforementioned surface adhesion force, tear strength to MD, and surface adhesion value of resin film-1~resin film-7 to the tear strength to MD (surface adhesion/tear strength to MD) The evaluation results of puncture strength, and recovery time are shown in Table 2. In addition, "-" in Table 2 indicates that no evaluation has been performed.

[Table 2] Remarks Example Comparative example Reference example Resin film No. 1 2 3 4 5 6 7 Evaluation Extraction amount of water-soluble cellulose derivatives (µg/m ² ) 15 15 14 10 9 - - Surface adhesion/tear strength to MD 0.39 0.36 0.41 0.45 0.42 - - Surface adhesion (N) 12.9 12.3 13.2 14.4 14.2 - - Tear strength to MD (mN) 33.4 34.0 32.3 31.8 33.7 - - Haze value (%) 0.45 0.45 0.46 0.31 0.30 - 0.86 Puncture strength (N) 3.1 3.1 3.1 3.0 3.1 4.2 - Recovery time (second) 81 80 86 99 91 - -

According to Table 2, the ratio of the surface adhesion value (N) to the value of the tearing strength to MD (mN) is 0.35 or more and less than 0.41, resin film-1 and resin film-2, and other resin films -3~Resin film -5, the recovery time from the rewinding state is significantly shorter.

In addition, according to Table 1, the resin film-1 and resin film-2 are manufactured in the following manner: the resin composition is used, that is, the monomer used to synthesize the vinylidene chloride resin by polymerization It is obtained by suspension polymerization in an aqueous medium in the presence of a water-soluble cellulose derivative with a total mass of the aforementioned monomers of 300 ppm or more and 600 ppm or less, and the aforementioned resin composition is melted and extruded to obtain MD The stretching ratio is 3.5 times or more and 5.0 times or less, the stretching ratio in TD is 4.0 times or more and 5.5 times or less, and the relaxation ratio in MD is 10.0% or more and 12.5% or less. Industrial availability

The resin film of the present invention is easy to peel the end portion from the wound portion in the rewind state without causing the resin film to tear in the longitudinal direction. Therefore, the resin film of the present invention can be suitably used for various purposes such as household use, experimental use, and industrial use.

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Claims (5)

A resin film, which is a resin film containing a vinylidene chloride resin composition, and The ratio of the value of surface adhesion (unit: N) to the value of tearing strength to MD (unit: mN) (the value of surface adhesion/the value of tearing strength to MD) is 0.35 or more and less than 0.41. The resin film according to claim 1, wherein the value of the tearing strength to MD is 32.0 mN or more and 34.5 mN or less, The value of the surface adhesion force is 12.0N or more and 13.0N or less. The resin film according to claim 1 or 2, wherein the haze value is 1.2% or less. The resin film according to claim 1, wherein the value of the puncture strength is less than 4.0N. A method for manufacturing a resin film, comprising: extending the melted and extruded vinylidene chloride resin composition; and relaxing the stretched vinylidene chloride resin composition; The vinylidene chloride-based resin composition is used to synthesize vinylidene chloride-based resin by polymerization. The monomer content relative to the total mass of the monomer is a water-soluble fiber with a content of 300 ppm or more and 600 ppm or less A resin composition obtained by suspension polymerization in an aqueous medium in the presence of a prime derivative, In the stretching step, the vinylidene chloride resin composition is stretched such that the stretching ratio in MD is 3.5 times or more and 5.0 times or less, and the stretching ratio in TD is 4.0 times or more and 5.5 times or less, and In the relaxation step, the stretched vinylidene chloride resin composition is relaxed so that the relaxation rate in MD is 9.5% or more and 12.5% or less.