JP5237156B2 - Polyvinyl chloride high stretch film - Google Patents

Description

  The present invention relates to a polyvinyl chloride high stretch film which has high stretch properties and can be suitably applied to food containers and packaging as well as various articles for business use, business use and home use. Specifically, the elongation at break in the width direction of the film is 300% or more even if the film thickness is thinner than the conventional polyvinyl chloride stretch film, and has the elongation and strength applicable to machine packaging. The present invention relates to a polyvinyl chloride high stretch film having excellent packaging suitability.

Various stretch films have been developed as food container packaging films, and are widely used as food packaging, particularly for packaging fresh foods such as meat, fresh fish and fruits and vegetables together with containers. At the same time, high-stretch automatic packaging machines, push-up automatic packaging machines, pillow-type automatic packaging machines, etc. have been developed and improved as automatic packaging machines that use these films to package foods, thereby improving the efficiency of food container packaging. ing.
On the other hand, the stretch film for food container packaging needs to be excellent in performance such as transparency, antifogging property, flexibility and heat sealability.
As a material for stretch films for packaging food containers, films made of vinyl chloride resin have long been applied to satisfy various performances.
Various plasticizers are added to the vinyl chloride resin in order to give the necessary performance as a stretch film as described above. Therefore, a plasticizer for a stretch film has been studied which imparts excellent performance and does not cause environmental problems.

  As a polyvinyl chloride stretch film, diisononyl adipate, di-n-alkyl adipate having a straight-chain alkyl group having 6, 8 or 10 carbon atoms, straight-chain and / or side-chain alkyl having 7 or 9 carbon atoms A product using a dialkyl ester selected from the group consisting of a dialkyl adipate having a group and di (2-ethylhexyl) azelate as a plasticizer is commercially available (Japanese Patent No. 1569334).

  In recent years, there has been a demand for a polyvinyl chloride stretch film that is compatible with the progress of food container packaging technology and the like, especially with the transition of fresh food distribution and food sales methods in large stores. In particular, various plasticizers that impart performance as a packaging material to a polyvinyl chloride stretch film have been studied. In JP-A-7-149924, by using diisononyl adipate and adipic acid diester having an alkyl group having 6 to 8 carbon atoms as a plasticizer, the film thickness is as thin as 12.5 to 14.5 μm, and transparency is also provided. It discloses that a good stretch film can be obtained.

  In JP-A-2002-293957, an adipic acid polyester plasticizer having an average molecular weight of 1000 to 3000 as a plasticizer, an adipic acid ester plasticizer having an alkyl group having 8 or more carbon atoms, and / or 10 carbon atoms. A polyvinyl chloride stretch film using a mixed adipic ester plasticizer obtained by reaction of two or more aliphatic alcohols having an alkyl group and adipic acid is disclosed. According to the present invention, even when the film thickness is reduced to 12 μm or less, it is not broken during use, and the extrudability is very good.

Furthermore, in Japanese Patent Application Laid-Open No. 2006-104241, a chlorination containing a plasticizer composed of an adipic acid polyester plasticizer having a weight average molecular weight of 1000 to 3000 and an acrylic polymer having a weight average molecular weight of 1000 to 3500 is used as a plasticizer. A polyvinyl chloride stretch film using a vinyl resin composition is disclosed. Similarly, in JP-A-2006-104242, as a plasticizer, adipic acid polyester plasticizer having a weight average molecular weight of 1000 to 3000, two or more aliphatic alcohols having an alkyl group having 10 or less carbon atoms, and adipic acid A polyvinyl chloride stretch film using a vinyl chloride resin composition containing a mixed adipic ester plasticizer obtained by the reaction is disclosed.
These stretch films are thin films of 10 μm or less, are excellent in automatic packaging characteristics and antifogging properties of food containers, and have an n-heptane extraction amount of 30 to 50 ppm or less.
As is clear from the above inventions and the like, there is a strong demand for a polyvinyl chloride stretch film that satisfies various physical properties and does not break even when the film thickness is reduced, and has excellent automatic packaging suitability for food containers and packaging. Various proposals have been made.

Japanese Patent No. 1569334 JP-A-7-149924 JP 2002-293957 A JP 2006-104241 A JP 2006-104242 A

  The problem of the present invention is that even when the thickness of the film is reduced to about 10 μm or less, the maximum elongation at break in the width direction is 300% or more, and as a food container packaging film by a high stretch automatic packaging machine, It is to provide a polyvinyl chloride high stretch film excellent in suitability for packaging machines.

  The present inventors have intensively studied to solve the above problems, and as a result, a vinyl chloride resin having an average degree of polymerization of 1300, a dialkyl ester adipic acid plasticizer (A) as a plasticizer, and an average molecular weight of 388. A stretch comprising a vinyl chloride resin composition containing a specific amount of a triethylene glycol compound (B) and an epoxidized vegetable oil (C) constituting benzoic acid, 2-ethylhexylic acid and a diester at both ends of the molecule Even if the film is a thin film having a thickness of about 10 μm, the maximum elongation at break in the direction perpendicular to the film extrusion direction (MD) (hereinafter referred to as the width direction TD) is 300% or more. The present inventors have found that this is a polyvinyl chloride high stretch film having excellent packaging suitability by an automatic food container packaging machine, and has led to the present invention.

  That is, the present invention relates to 100 parts by weight of a vinyl chloride resin having an average degree of polymerization of 1300, 8 to 32 parts by weight of an adipic acid dialkyl ester plasticizer [plasticizer (A)], and an average molecular weight of 388. 8 to 32 parts by weight of a triethylene glycol compound [plasticizer (B)] constituting benzoic acid and 2-ethylhexylic acid and a diester, respectively, and the total amount of plasticizer (A) and plasticizer (B) is 28 to 42 It is a range of parts by weight and is a polyvinyl chloride high stretch film comprising a vinyl chloride resin composition containing 10 to 20 parts by weight of epoxidized vegetable oil [plasticizer (C)] as a plasticizer. The polyvinyl chloride high stretch film has a maximum elongation of 300% or more when the film is broken in the width direction.

According to the polyvinyl chloride high stretch film of the present invention, even if the film thickness is reduced to 12 μm or less, particularly about 10 μm, the film is stretched in the width direction, that is, in the direction perpendicular to the extrusion direction of film production. Large, maximum elongation at break is 300% or more, excellent packaging characteristics by automatic food container packaging machine, and when packaging food containers, it does not break even when stretched, and is transparent and smooth to the touch Food container packaging with excellent antifogging properties is possible.
As a food container packaging, it can be applied not only to manual packaging but also to packaging by an automatic packaging machine without impairing the performance required conventionally. In addition, since the film thickness can be reduced, the manufacturing cost of the polyvinyl chloride stretch film can be reduced, the amount of used film collected can be reduced, and the collection work efficiency can be improved.

Hereinafter, the present invention will be specifically described.
The vinyl chloride resin used in the present invention is a vinyl polymer mainly composed of vinyl chloride, and is a vinyl chloride homopolymer or a monomer copolymerizable with vinyl chloride, such as vinyl acetate, vinylidene chloride, maleic acid. Examples thereof include copolymers with diesters, ethylene, propylene, and the like. These vinyl chloride resins may be those obtained by usual polymerization methods such as emulsion polymerization, suspension polymerization, solution polymerization, and bulk polymerization. Preferably, a vinyl chloride homopolymer or a vinyl chloride copolymer having an average degree of polymerization of 1300 is used. The average degree of polymerization of the vinyl chloride resin is a value determined according to JIS K6721.
If the average degree of polymerization of the vinyl chloride resin is 1300, the flowability of the vinyl chloride resin composition is good, the film extrusion property is excellent, and the physical properties, heat resistance, and food container of the film as a stretch film Excellent packaging characteristics and anti-fogging properties with automatic pavers.

  The plasticizer used in the present invention is an adipic acid dialkyl ester plasticizer [plasticizer (A)], an average molecular weight of 388 and a triester constituting diester with benzoic acid and 2-ethylhexyl acid at each of both ends of the molecule. An ethylene glycol compound [plasticizer (B)] and an epoxidized vegetable oil [plasticizer (C)].

  Plasticizer (A) is a dipic acid di-n-alkyl ester having a linear alkyl group having 6, 8 or 10 carbon atoms, specifically, di-n-hexyl adipate, di-n-octyl adipate Adipic acid di-n-decyl and the like, and adipic acid di-n-alkyl ester or adipic acid diiso-alkyl ester having a linear or side chain alkyl group having 7 or 9 carbon atoms, specifically, Examples include di-n-heptyl adipate, di-n-nonyl adipate, diiso-heptyl adipate, diiso-nonyl adipate, and di (2-ethylhexyl) azelate. Most preferably, adipine The acid iso-nonyl is used.

  The plasticizer (B) is a triethylene glycol compound having an average molecular weight of 388 and constituting benzoic acid, 2-ethylhexylic acid and a diester at both ends of the molecule. For example, the brand name of LG Chemical Co., Ltd. in Korea: LGflex EBN. What is marketed as W (molecular weight: 388, CAS Number: 65227-26-0) is mentioned. The polyvinyl chloride high stretch film of the present invention is characterized in that the compound is contained as a plasticizer (B), and even if the film thickness is thinner than a conventional stretch film, sufficient strength and It has packaging suitability.

In the vinyl chloride resin composition for obtaining the polyvinyl chloride high stretch film of the present invention, the content of the plasticizer (A) and the plasticizer (B) is 100 parts by weight of the vinyl chloride resin. The plasticizer (A) is 8 to 32 parts by weight, the plasticizer (B) is 8 to 32 parts by weight, and the total amount of the plasticizer (A) and the plasticizer (B) is 28 to 42 parts by weight. Range. Preferably, the plasticizer (A) is 10 to 30 parts by weight, the plasticizer (B) is 10 to 30 parts by weight, and the total amount of the plasticizer (A) and the plasticizer (B) is 30 to 30 parts by weight. The range is 40 parts by weight.
When the total amount of the plasticizer (A) and the plasticizer (B) is less than 28 parts by weight, it is easily cut when stretched to a desired magnification in the width direction when packaging food containers by an automatic packaging machine, and the suitability of the packaging machine is not good. . On the other hand, when it exceeds 42 parts by weight, the suitability of the packaging machine is good, but the roll film peeling property of the stretch film wound in a roll shape is not preferable, it is slippery, and the end face of the roll roll of the stretch film occurs. And the suitability of the packaging machine is reduced. Moreover, it is unpreferable at the point which the hue of the film of the state wound on the roll becomes dark and the appearance is impaired.

The vinyl chloride resin composition according to the present invention contains epoxidized vegetable oil as the plasticizer (C) in addition to the plasticizer (A) and the plasticizer (B). Epoxidized vegetable oil is mainly obtained by epoxidizing soybean, linseed oil or the like. Examples include epoxidized soybean oil containing epoxidized oleic acid and epoxidized linoleic acid, and epoxidized linseed oil containing epoxidized oleic acid, epoxidized linoleic acid and epoxidized linolenic acid.
In the vinyl chloride resin composition according to the present invention, epoxidized soybean oil can be preferably used, but is not particularly limited.

  In the vinyl chloride resin composition for obtaining the polyvinyl chloride high stretch film of the present invention, the content of the epoxidized vegetable oil [plasticizer (C)] is 10 to 100 parts by weight of the vinyl chloride resin. It is 20 weight part, and the high stretch film with favorable packaging machine suitability is obtained in the range of this content. When the content is less than 10 parts by weight and exceeds 20 parts by weight, the suitability of the resulting film for a packaging machine tends to be insufficient.

  Furthermore, in the vinyl chloride resin composition according to the present invention, if necessary, in an amount within the range not inhibiting the effects of the present invention, in addition to the plasticizer, an antioxidant, an ultraviolet absorber, an antistatic agent, Lubricants, pigments, surfactants and the like can be included.

The polyvinyl chloride high stretch film of the present invention contains the above-mentioned specific plasticizer (A), plasticizer (B) and plasticizer (C), and additives as necessary with respect to the vinyl chloride resin. A vinyl chloride resin composition is prepared by uniformly mixing by a usual mixing method using a commonly used mixer such as a Henschel mixer, and the resulting composition is subjected to a T-die or inflation method, etc. A stretch film can be obtained by forming a film by the film forming method.
Even if the resulting stretch film is a thin film having a thickness of about 10 μm, the maximum elongation at break in the film width direction based on the standard of JIS K7127 (the tensile test method for plastic film and sheet) exceeds 300%. A food container automatic packaging machine having a draw ratio of 2.2 times in the width direction of the film, for example, “AW-3600” manufactured by Teraoka Seiko Co., Ltd. also exhibits good packaging machine suitability.

  The polyvinyl chloride high stretch film of the present invention can be used mainly for packaging food containers and other various articles, and for home use or business use. In contrast to the stretch film having a thickness of about 12 μm, which is conventionally used for commercial automatic packaging machines, the stretch film of the present invention is transparent as a stretch film even if the thin film is a thin film of about 10 μm. Excellent in properties, strength, elongation, anti-fogging property, self-adhesiveness, etc., excellent in suitability for automatic packaging machines, can reduce the production cost of stretch film, and collect and recover used film It can also contribute to the reduction of the amount.

  Hereinafter, the present invention will be described in detail together with comparative examples by way of examples. However, the present invention is not limited by these examples.

  100 parts by weight of vinyl chloride resin [ethylene-vinyl chloride copolymer (ethylene 1%); Taiyo PVC Co., Ltd. TH-1300], 10 parts by weight of diisononyl adipate (DINA) and benzoic acid at both ends of the molecule Acid and 2-ethylenehexyl acid and diethylene glycol compound [LG Chemical Co., Ltd. (Korea), Brand name: LGflex EBN. W] A total amount of 32 parts by weight with 22 parts by weight and epoxidized soybean oil [Daicel Chemical Industries, Ltd., product abbreviation: ESBO], 15 parts by weight, and 1.0 part by weight of a Ca-Zn stabilizer, A vinyl chloride resin composition prepared by heating and mixing 1.5 parts by weight of poly (di) glycerin fatty acid ester, 1.0 part by weight of sorbitan fatty acid ester and 1.0 part by weight of polyoxyethylene alkyl ether was screw kneaded with an extruder. Then, melt extrusion was performed at about 210 ° C. from the T-die, and it was wound up by a drawing winder. The films were wound into rolls having a thickness of 12 μm, 10 μm, and 8 μm and a width of 300 mm. The obtained high stretch film was subjected to a packaging test by the following test method using a tensile property and an automatic packaging apparatus [AW-3600 manufactured by Teraoka Seiko Co., Ltd.]. The suitability of the packaging machine such as peelability, cutability, wrinkles, and gripping slip was evaluated, and the results are shown in Table-1.

[Maximum elongation at break and breaking strength]
Using “Tensile testing machine: UCT-500” manufactured by Orientec Co., Ltd., using a No. 2 test piece (10 mm × 100 mm) based on JIS K7127, the film was formed at a temperature of 23 ± 2 ° C. and a tensile speed of 500 mm / min. The maximum elongation and strength until breakage were determined.
[Hue]
The hue of the stretch film wound in roll shape was evaluated by visual sensation.
○: Good ×: Bad (becomes dull color)
[Packaging machine suitability]
Peelability : When pulling out from a roll-shaped wound body, it is in a state where it is pulled out, such as slipping, shifting, or loose
Evaluated.
○: Good without causing any problems.
Δ: Some problem.
×: Difficult to pull out, causing a problem such as slipping and the roll end gradually breaking.
Cutability : Cutability at the time of machine packaging was evaluated.
○: Cut well.
X: Cut is not smooth.
Wrinkle : Evaluates the presence or absence of wrinkles when pulled out from the roll or on the film surface of the package
did.
○: Wrinkles do not occur.
X: Wrinkles are generated in the package, and wrinkles are generated without being smoothly pulled out.
Gripping and sliding : A state where the film is gripped by a belt that grips and conveys the film from both sides.
Evaluated.
○: There is no disconnection.
X: Easily comes off and causes defective packaging.
Comprehensive evaluation of suitability for packaging machines :
A: Good Δ: Insufficient applicability.
×: There is a problem

  In the same manner as in Example 1, films were prepared by changing the amount of plasticizer used as shown in Table 1, the tensile properties of each film were measured, and the hue and packaging machine suitability were evaluated. The results are summarized in Table 1.

  In the same manner as in Example 1, films were prepared by changing the amount of plasticizer used as shown in Table 1, the tensile properties of each film were measured, and the hue and packaging machine suitability were evaluated. The results are summarized in Table 1.

  In the same manner as in Example 1, films were prepared by changing the amount of plasticizer used as shown in Table 1, the tensile properties of each film were measured, and the hue and packaging machine suitability were evaluated. The results are summarized in Table 1.

  In the same manner as in Example 1, films were prepared by changing the amount of plasticizer used as shown in Table 1, the tensile properties of each film were measured, and the hue and packaging machine suitability were evaluated. The results are summarized in Table 1.

  In the same manner as in Example 1, films were prepared by changing the amount of plasticizer used as shown in Table 1, the tensile properties of each film were measured, and the hue and packaging machine suitability were evaluated. The results are summarized in Table 1.

Comparative Examples 1-6
In the same manner as in Example 1, the amount of the plasticizer used was changed for the test. Table 1 summarizes the results of measuring the tensile properties of each film and evaluating the hue and suitability of the packaging machine.

Note) The following is shown in Table-1.
The plasticizer (A) is diisononyl adipate [J Plus, product name: DINA],
The plasticizer (B) is a triethylene glycol compound having an average molecular weight of 388 and constituting benzoic acid and 2-ethylhexylic acid and a diester at both ends of the molecule [LG Chemical Co., Ltd. (Korea), brand name: LGflex EBN. W],
The plasticizer (C ) is epoxidized soybean oil [Daicel Chemical Industries, Ltd., product abbreviation: ESBO].

  As a stretch film for food container packaging, the maximum elongation at break exceeds 300% even though the film thickness is thinner than the current product, with excellent breaking strength and applicability to food container automatic packaging machines. The production cost of the film, the application efficiency and the collection efficiency for food container packaging improved, and the industrial applicability as a high stretch film for food container packaging greatly improved.

Claims (2)

Adipic acid dialkyl ester plasticizer [plasticizer (A)] 8 to 32 parts by weight per 100 parts by weight of vinyl chloride resin having an average polymerization degree of 1300, an average molecular weight of 388, and benzoic acid and 2 -Triethylene glycol compound [plasticizer (B)] constituting ethylhexyl acid and diester is 8 to 32 parts by weight, and the total amount of plasticizer (A) and plasticizer (B) is in the range of 28 to 42 parts by weight. A polyvinyl chloride high stretch film comprising a vinyl chloride resin composition containing 10 to 20 parts by weight of an epoxidized vegetable oil [plasticizer (C)] as a plasticizer,
A polyvinyl chloride high stretch characterized by having a maximum elongation of 300% or more at break in the width direction of the film measured at a temperature of 23 ± 2 ° C. and a tensile speed of 500 mm / min based on JIS K7127 the film.   The polyvinyl chloride high stretch film according to claim 1, wherein the dialkyl adipate plasticizer is diisononyl adipate.