JPWO2011021400A1 - Polyvinyl chloride stretch film - Google Patents

Abstract

An object of the present invention is to provide a polyvinyl chloride stretch film having a high breaking strength and an appropriate elongation even when the film thickness is as thin as about 8 μm compared to a conventional film having a thickness of 10 μm. . The polyvinyl chloride stretch film of the present invention comprises 100 parts by weight of a vinyl chloride resin, an adipic acid dialkyl ester plasticizer (A1), and an adipic acid polyester plasticizer (A2) having a weight average molecular weight of 1000 to 3000. A triester constituting 0 to 15 parts by weight of one or more plasticizers (A) selected from the group, hydroxyl groups at both ends of the molecule, and each of benzoic acid and 2-ethylhexylic acid to form a diester 10 to 30 parts by weight of a plasticizer (B) made of an ethylene glycol compound and 10 to 20 parts by weight of a plasticizer (C) made of an epoxidized vegetable oil, and a plasticizer (A) and a plasticizer (B) It consists of a vinyl chloride-type resin composition whose total amount is 20-35 weight part.

Description

  The present invention relates to a polyvinyl chloride stretch film. For details, use a PVC stretch film suitable for packaging with a push-up type automatic packaging machine that pushes up a packaging container containing fresh food etc. The present invention relates to a polyvinyl chloride stretch film suitable for packaging.

  Various fresh foods, processed foods, etc. are packaged with plastic films in order to maintain their freshness and improve their appearance. In the packaging of food, particularly fresh food, in order to maintain the freshness of the food, it is necessary to stretch the film and wrap the food together with the container, and seal and seal the film. Various stretch films have been developed as food container packaging films used for such packaging, and are widely used as food packaging, especially for packaging fresh foods such as meat, fresh fish and fruits and vegetables with containers. . In addition, high-stretch automatic packaging machines, push-up automatic packaging machines, pillow-type automatic packaging machines, etc. have been developed as automatic packaging machines that use these films to package food. It is illustrated.

  Among such automatic packaging machines, a push-up type automatic packaging machine, for example, (1) places a container (hereinafter referred to as a food container) containing articles such as food on a belt and horizontally A transport unit for transporting, (2) a lift device that is provided at the terminal position of the transport unit and pushes the transported food container upward, and (3) a film supply mechanism for wrapping the pushed food container with a packaging film; Packaging mechanism, (4) film folding means for packaging and sealing the food container, and heating means for heating and fusing the folded film, and (5) carrying out the finally packaged food container It consists of various incidental facilities to do. In such a push-up type automatic packaging machine, the food container covers the pushed-up food container with a packaging film, stretches the film in the vertical and horizontal directions, wraps it, heats the folded and overlapped film, etc. And sealed and packaged.

  On the other hand, a stretch film for packaging food containers needs to be excellent in performance such as transparency, antifogging property, flexibility and heat sealability. Therefore, as a stretch film for food container packaging, a film mainly composed of a vinyl chloride resin has been conventionally used as a film satisfying various performances (see, for example, Patent Documents 1 to 5). Various plasticizers are added to the vinyl chloride resin in order to impart the performance required for the stretch film as described above. Therefore, as plasticizers for stretch films, those that impart excellent performance and do not cause environmental problems have been studied.

  For example, in Patent Document 1, diisononyl adipate as a plasticizer, di-n-alkyl adipate having a straight-chain alkyl group having 6, 8 or 10 carbon atoms, straight-chain and / or side having 7 or 9 carbon atoms A polyvinyl chloride-based stretch film containing a dialkyl adipate having a chain alkyl group and a dialkyl adipate selected from the group consisting of di (2-ethylhexyl) adipate is disclosed.

  In recent years, it has been demanded that the polyvinyl chloride stretch film be adapted to the progress of distribution of fresh foods, changes in food sales methods in large stores, and food container packaging technology. In particular, various plasticizers that impart performance as a packaging material to a polyvinyl chloride stretch film have been studied. In Patent Document 2, by using diisononyl adipate and an 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 good. It is disclosed that a stretch film can be obtained.

  In Patent Document 3, an adipic acid polyester plasticizer having an average molecular weight of 1000 to 3000, an adipic acid ester plasticizer having an alkyl group having 8 or more carbon atoms, and / or an alkyl group having 10 or less carbon atoms is used as a plasticizer. A polyvinyl chloride stretch film using a mixed adipate ester plasticizer obtained by reaction of two or more aliphatic alcohols having adipic acid is disclosed. In Patent Document 3, it is said that even if the film thickness is reduced to 12 μm or less, it is not broken during use, and the extrusion moldability is extremely good.

  In Patent Document 4, a vinyl chloride resin composition containing, as plasticizers, 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. A polyvinyl chloride stretch film is disclosed. Similarly, in Patent Document 5, as a plasticizer, an adipic acid polyester plasticizer having a weight average molecular weight of 1000 to 3000, a reaction of two or more aliphatic alcohols having an alkyl group with 10 or less carbon atoms, and adipic acid are used. A polyvinyl chloride stretch film comprising a vinyl chloride resin composition containing the obtained mixed adipate ester plasticizer 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 ppm to 50 ppm.

Japanese Patent No. 15969334 JP-A-7-149924 JP 2002-293957 A JP 2006-104241 A JP 2006-104242 A

  By the way, a stretch film for packaging food containers, particularly a polyvinyl chloride stretch film used for packaging by a push-up type automatic packaging machine, has a high breaking strength even if the film thickness is thin from the viewpoint of reducing costs. Is required. However, since conventional polyvinyl chloride-based stretch films contain a large amount of adipic acid alkyl ester such as diisononyl adipate as a plasticizer, the breaking strength when the film thickness is reduced may be insufficient. Thus, there is a demand for a polyvinyl chloride stretch film excellent in automatic packaging and having high breaking strength that does not break even when the film thickness is reduced while satisfying various physical properties as a food container packaging film. Yes.

  The present invention has been made in view of the above circumstances, and has a conventional film thickness of 10 μm as a polyvinyl chloride stretch film while having various physical properties such as transparency, flexibility, restorability and heat sealability. To provide a polyvinyl chloride stretch film having excellent breaking strength and elongation even when the film thickness is as thin as 8 μm; especially suitable for packaging food storage containers by a push-up type automatic packaging machine An object is to provide a vinyl chloride stretch film.

  The present inventors have provided a polyvinyl chloride stretch containing “a triethylene glycol compound that forms a diester by dehydration condensation reaction with hydroxyl groups at both ends of the molecule and each of benzoic acid and 2-ethylhexyl acid” as a plasticizer. It has been found that since the film has a high breaking strength, the film thickness can be reduced. On the other hand, since a film containing “a triethylene glycol compound that constitutes a diester by dehydration condensation reaction between hydroxyl groups at both ends of the molecule and benzoic acid or 2-ethylhexyl acid” tends to be brittle, the elongation at break decreases. There was also a problem that it became easier. Therefore, in the present invention, the total amount of the plasticizer (A) comprising an adipic acid alkyl ester and the plasticizer (B) comprising the aforementioned triethylene glycol compound is adjusted, more preferably the plasticizer (A) and the plasticizer. By adjusting the blending ratio of (B), etc., it is possible to adjust the balance between the breaking strength and the elongation rate of the stretch film. It was. The present invention has been made based on such findings.

The present invention relates to the following polyvinyl chloride stretch films.
[1] Adipic acid dialkyl ester plasticizer (A1) which is a reaction product of 100 parts by weight of vinyl chloride resin, adipic acid and an aliphatic alcohol having an alkyl group having 6 or more carbon atoms, and a weight average molecular weight of 1000 to 1000 1 to 15 parts by weight of one or more plasticizers (A) selected from the group consisting of 3000 adipic acid polyester plasticizers (A2), hydroxyl groups at both ends of the molecule, benzoic acid and 2-ethylhexylic acid 10 to 30 parts by weight of a plasticizer (B) made of a triethylene glycol compound that forms a diester by dehydration condensation reaction, and 10 to 20 parts by weight of a plasticizer (C) made of an epoxidized vegetable oil, A polyvinyl chloride resin comprising a vinyl chloride resin composition containing and having a total amount of the plasticizer (A) and the plasticizer (B) of 20 to 35 parts by weight. Le stretch film.
[2] The polyvinyl chloride stretch film according to [1], wherein the plasticizer (A) is diisononyl adipate.
[3] The polyvinyl chloride stretch film according to [1] or [2], wherein the plasticizer (A) / the plasticizer (B) is 0.65 or less by weight.
[4] The polyvinyl chloride stretch film according to any one of [1] to [3], wherein the triethylene glycol compound is represented by the following formula.

［８］ 前記可塑剤（Ａ１）／前記可塑剤（Ｂ）が、重量比で０．８以上である、［５］〜［７］のいずれかに記載のポリ塩化ビニル系ストレッチフィルム。[5] Dehydration of 100 parts by weight of vinyl chloride resin, 8 to 32 parts by weight of adipic acid dialkyl ester plasticizer (A1), hydroxyl groups at both ends of the molecule, benzoic acid and 2-ethylhexylic acid 8 to 32 parts by weight of a plasticizer (B) composed of a triethylene glycol compound constituting a diester by a condensation reaction, and 10 to 20 parts by weight of a plasticizer (C) composed of an epoxidized vegetable oil, and the plasticizer A polyvinyl chloride stretch film comprising a vinyl chloride resin composition in which the total amount of (A1) and the plasticizer (B) is 28 to 42 parts by weight.
[6] The polyvinyl chloride stretch film according to [5], wherein the plasticizer (A) is diisononyl adipate.
[7] The polyvinyl chloride stretch film according to [5] or [6], wherein the triethylene glycol compound is represented by the following formula.

[8] The polyvinyl chloride stretch film according to any one of [5] to [7], wherein the plasticizer (A1) / the plasticizer (B) is 0.8 or more by weight.

  The polyvinyl chloride stretch film of the present invention has various physical properties such as transparency, flexibility, resilience and heat sealability, and is as thin as about 8 μm compared to a conventional film having a thickness of 10 μm. Is excellent in breaking strength and elongation characteristics. For this reason, the polyvinyl chloride-based stretch film is particularly suitable for packaging food storage containers using a push-up type automatic packaging machine or a high stretch type automatic packaging machine. In addition, the polyvinyl chloride stretch film of the present invention has excellent packaging characteristics without tearing or wrinkling. Furthermore, since the film can be made thinner, the manufacturing cost of the polyvinyl chloride stretch film can be reduced, and further, the amount of recovered stretch film can be reduced and the recovery work efficiency can be improved.

  The polyvinyl chloride stretch film of the present invention comprises 1) a vinyl chloride resin, 2) an adipic acid dialkyl ester plasticizer (A1), and an adipic acid polyester plasticizer (A2) having an average molecular weight of 1000 to 3000. One or more plasticizers (A) selected from 3), a plasticizer comprising a triethylene glycol compound constituting a diester by a dehydration condensation reaction between hydroxyl groups at both ends of the molecule and benzoic acid and 2-ethylhexylic acid ( It consists of a vinyl chloride resin composition containing B) and 4) a plasticizer (C) made of epoxidized vegetable oil.

  The vinyl chloride resin contained in the vinyl chloride resin composition is a vinyl chloride polymer that contains vinyl chloride-derived constituent units as the main constituent units. Vinyl chloride homopolymers or other copolymers with vinyl chloride are possible. It may be a copolymer (vinyl chloride copolymer) with another monomer. In order to increase the mechanical strength of the film, a vinyl chloride homopolymer is preferable.

  Examples of the copolymerizable monomer in the vinyl chloride copolymer include vinyl acetate, vinylidene chloride, maleic acid diester, ethylene and propylene. The content of the structural unit derived from the copolymerizable monomer contained in the vinyl chloride copolymer is preferably 10 mol% or less.

  The average degree of polymerization of the vinyl chloride resin is preferably 1000 to 1300. If the average degree of polymerization of the vinyl chloride resin is in the above range, the fluidity when the resin composition containing the vinyl chloride resin is melted is good, so that the film can be easily formed by extrusion. Moreover, it is because it is excellent also in physical properties, such as film strength as a stretch film, rubber elasticity, heat resistance, anti-fogging property, etc., and it is excellent also in the packaging characteristic by a food container automatic packaging machine. The average degree of polymerization of the vinyl chloride resin is a value measured by a method based on JIS K6721.

  The vinyl chloride resin used for a film suitable for packaging by a push-up type automatic packaging machine is preferably a vinyl chloride homopolymer having an average degree of polymerization of about 1000. The vinyl chloride resin contained in a film suitable for packaging by a high stretch type automatic packaging machine preferably has an average degree of polymerization of about 1300.

  The vinyl chloride resin may be obtained by a usual polymerization method such as emulsion polymerization, suspension polymerization, solution polymerization and bulk polymerization.

  The plasticizer (A) contained in the vinyl chloride resin composition is a dipic acid dialkyl ester plasticizer (A1), which is a reaction product of an aliphatic alcohol having an alkyl group having 6 or more carbon atoms and adipic acid, and a weight average. It is one or more selected from the group consisting of an adipic acid-based polyester plasticizer (A2) having a molecular weight of 1000 to 3000, preferably an adipic acid dialkyl ester plasticizer (A1). These plasticizers (A) can impart high elongation characteristics to the film. The weight average molecular weight of the adipic acid-based polyester plasticizer can be measured by a GPC analysis method or the like.

  The adipic acid dialkyl ester plasticizer (A1) can be a reaction product of an aliphatic alcohol and adipic acid. Examples of the aliphatic alcohol include an aliphatic alcohol containing an alkyl group having 6 or more carbon atoms, preferably a linear alkyl group having 6, 8 or 10 carbon atoms, or 7 carbon atoms. Alternatively, aliphatic alcohols having 9 linear or side chain alkyl groups are included. The aliphatic alcohol in the adipic acid dialkyl ester plasticizer may be one kind or two kinds.

  Examples of dialkyl adipate plasticizers (A1) include di-n-hexyl adipate, di-n-octyl adipate, di-n-decyl adipate, diisoheptyl adipate, diisononyl adipate, and di (2-ethylhexyl) An azelate and the like are included, and diisononyl adipate is preferable. The adipic acid dialkyl ester plasticizer (A1) contained in the vinyl chloride resin composition may be a single type or a mixture of two or more types. Examples of the adipic acid-based polyester plasticizer (A2) that is a mixture of two or more types include adipic acid n-alkyl mixed esters (n-alkyl: C6, C8, and C10).

  The adipic acid-based polyester plasticizer (A2) having a weight average molecular weight of 1000 to 3000 is a reaction product of adipic acid and a dihydric alcohol. Examples of the dihydric alcohol include ethylene glycol, propylene glycol, butanediol, 1.6-hexanediol and the like. Only one type of dihydric alcohol in the adipic acid-based polyester plasticizer may be used, or two or more types may be combined.

  The adipic acid type polyester plasticizer (A2) having a weight average molecular weight of 1000 to 3000 can impart solvent extraction resistance to the film. A film containing an adipic acid-based polyester plasticizer having a weight average molecular weight of less than 1000 is excellent in solvent extraction resistance. A resin composition containing an adipic acid-based polyester plasticizer having a weight average molecular weight exceeding 3000 may have low fluidity when melted.

The plasticizer (B) contained in the vinyl chloride resin composition comprises a repeating unit derived from triethylene glycol, reacted with a compound having hydroxyl groups at both molecular ends, benzoic acid and 2-ethylhexylic acid. It contains a triethylene glycol compound that constitutes the diester. The triethylene glycol compound is preferably represented by the following formula.

  The number n of repetitions in the above formula is 1-6, preferably 1. When n in the above formula is more than 1, the weight average molecular weight of the plasticizer (B) is preferably 1000 or less.

  The triethylene glycol compound can be obtained by reacting a compound containing a repeating unit derived from triethylene glycol and having hydroxyl groups at both molecular ends with benzoic acid and 2-ethylhexyl acid.

  The polyvinyl chloride stretch film of the present invention is characterized in that it contains the triethylene glycol compound as a plasticizer (B). Such a triethylene glycol compound not only can impart elongation properties to the film, but can also significantly increase the breaking strength of the film. Even if the film containing such a triethylene glycol compound is thinner than a conventional stretch film, it has sufficient breaking strength, can be stretched at an appropriate magnification, and is suitable for packaging machines. is there.

  The contents of the plasticizer (A) and the plasticizer (B) in the vinyl chloride resin composition constituting the polyvinyl chloride stretch film of the present invention can be appropriately adjusted according to the packaging style.

  For example, a stretch film for push-up type automatic packaging is required to have a higher breaking strength while having an appropriate elongation. The content of the plasticizer (A) in the vinyl chloride resin composition constituting the polyvinyl chloride stretch film for push-up type automatic packaging is preferably 0 to 15 weights with respect to 100 parts by weight of the vinyl chloride resin. Parts, more preferably 5 to 10 parts by weight; the content of the plasticizer (B) is preferably 10 to 30 parts by weight, more preferably 15 parts per 100 parts by weight of the vinyl chloride resin. And the total amount of plasticizer (A) and plasticizer (B) is preferably 20 to 35 parts by weight, more preferably 25 to 30 parts by weight.

  When the total amount of the plasticizer (A) and the plasticizer (B) is less than 25 parts by weight, the elongation percentage of the film becomes low. In addition, the peeling force of the film is increased, and pulsation may occur when the film is pulled out from the wound body, and wrinkles may occur and the film may not be pulled out smoothly. On the other hand, when the total amount of the plasticizer (A) and the plasticizer (B) is more than 35 parts by weight, when the film is spread in the width direction (TD direction), the end of the film is slippery so that it is difficult to grasp and push up. It is easy to cause trouble in the process of wrapping the food container. When the total amount of the plasticizer (A) and the plasticizer (B) is in the range of 25 to 35 parts by weight, the strength of the film is sufficient and the packaging machine characteristics are also excellent.

  Further, the plasticizer (A) / plasticizer (B) in the vinyl chloride resin composition constituting the stretch film for push-up type automatic packaging is preferably 0.65 or less in weight ratio, and 0.3 or less. Is more preferable. This is because when the ratio of the plasticizer (B) to the plasticizer (A) is large, the breaking strength of the film can be increased. Therefore, the film in which the total amount of the plasticizer (A) and the plasticizer (B) is in the above range and the plasticizer (A) / plasticizer (B) is not more than a certain value has a sufficiently high breaking strength, A moderate elongation can be maintained.

  The stretch film for high stretch automatic packaging is required to have a higher elongation because it is pulled at a high stretch ratio. For this reason, in the stretch film for highly stretchable automatic packaging, it is preferable to increase the total amount of the plasticizers (A1) and (B).

  Specifically, the content of the plasticizer (A1) in the vinyl chloride resin composition constituting the polyvinyl chloride stretch film for high stretch automatic packaging of the present invention is 100 parts by weight of vinyl chloride resin. 8 to 32 parts by weight, preferably 10 to 30 parts by weight; the content of the plasticizer (B) is preferably 8 to 32 parts by weight, more preferably 10 to 30 parts by weight. Yes; and the total amount of plasticizer (A1) and plasticizer (B) is preferably in the range of 28 to 42 parts by weight, more preferably 30 to 40 parts by weight.

  When the total amount of the plasticizer (A1) and the plasticizer (B) is less than 28 parts by weight, the elongation percentage of the film is insufficient. For this reason, when food containers are packaged by an automatic packaging machine, they are easily cut when stretched at a high magnification in the width direction, and the suitability of the packaging machine may be insufficient. On the other hand, when the total amount of the plasticizer (A1) and the plasticizer (B) exceeds 42 parts by weight, the suitability of the packaging machine is good, but it becomes difficult to pull out from the wound body, or it becomes slippery. The end face of the bag is likely to be displaced and the suitability of the packaging machine is reduced. Moreover, it is not preferable also in that the hue of the film becomes dark and the appearance is impaired.

  Further, the plasticizer (A1) / plasticizer (B) in the vinyl chloride resin composition constituting the stretch film for high stretch automatic packaging is preferably 0.8 or more in weight ratio, 1.1. More preferably. This is because when the ratio of the plasticizer (A1) to the plasticizer (B) is large, the elongation percentage of the film can be increased. Therefore, a film in which the total amount of the plasticizer (A1) and the plasticizer (B) is in the above range and the plasticizer (A1) / plasticizer (B) is not less than a certain value has a sufficiently high elongation. And moderate break strength can be maintained.

  In addition to the plasticizer (A) and the plasticizer (B), the polyvinyl chloride stretch film of the present invention further includes a plasticizer (C) made of epoxidized vegetable oil. Epoxidized vegetable oil is mainly obtained by epoxidizing vegetable oil such as soybean oil or linseed oil. Examples of epoxidized vegetable oils 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, etc. It is.

  In the vinyl chloride resin composition for obtaining the polyvinyl chloride stretch film of the present invention, the content of the plasticizer (C) is 10 to 20 parts by weight with respect to 100 parts by weight of the vinyl chloride resin. preferable. Within this content range, a stretch film having excellent suitability for automatic packaging machines can be obtained. When the content of the plasticizer (C) is less than 10 parts by weight, the elongation rate of the film at a low temperature tends to decrease, and when it exceeds 20 parts by weight, the film end face shifts due to the bleed of the plasticizer (C). It tends to occur (it tends to be a bamboo shoot), and in any case, the suitability of the stretch film for a packaging machine is poor.

  In addition to the plasticizer (A), the plasticizer (B) and the plasticizer (C), the polyvinyl chloride stretch film of the present invention can be used as long as it does not inhibit the effects of the present invention. It may further contain additives such as a clouding agent, an antioxidant, an ultraviolet absorber, an antistatic agent, a lubricant, a pigment, and a surfactant.

  Examples of the antifogging agent include glycerin monofatty acid ester, polyglycerin fatty acid ester, sorbitan fatty acid ester and polyoxyethylene alkyl ether.

  The thickness of the polyvinyl chloride stretch film of the present invention is, for example, 12 μm or less, preferably 8 to 10 μm, although it depends on the packaging style.

  As described above, it is preferable that the polyvinyl chloride stretch film for push-up type automatic packaging has a sufficiently high breaking strength while having an appropriate elongation. For this reason, it is preferable that the polyvinyl chloride stretch film for push-up type automatic packaging has a breaking strength in the TD direction at 23 ° C. when the thickness is 10 μm of 1.7 N / cm or more, and 1.8 N / cm or more. It is more preferable that Further, the maximum elongation at break in the TD direction at 23 ° C. when the thickness of the polyvinyl chloride stretch film is 10 μm is preferably 200% or more, and more preferably 280% or more.

  Since a polyvinyl chloride stretch film for a high stretch type automatic packaging machine is pulled at a high magnification (for example, 232 times), it preferably has a sufficiently high elongation while having an appropriate breaking strength. For this reason, it is preferable that the polyvinyl chloride stretch film for a high stretch type automatic packaging machine has a maximum elongation at break in the TD direction at 23 ° C. when the thickness is 10 μm of 300% or more, and 400% or more. It is more preferable that it is 415% or more. The breaking strength of the film and the maximum elongation at break are measured by a method based on JISK7127.

  The polyvinyl chloride stretch film of the present invention can be produced by any method. For example, 1) Add the above plasticizer (A), plasticizer (B) and plasticizer (C) to the vinyl chloride resin, add other additives as necessary, and mix uniformly. A step of preparing a vinyl chloride resin composition; 2) a step of forming a film of the prepared vinyl chloride resin composition by an extrusion method such as a T-die method or an inflation die method; Can be manufactured. The mixing method of each component may be a normal mixing method using a mixer such as a Henschel mixer.

  The polyvinyl chloride stretch film of the present invention contains a plasticizer (B). Therefore, even if the polyvinyl chloride stretch film of the present invention is as thin as 8 μm, it includes a conventional polyvinyl chloride stretch having a film thickness of 10 μm and containing an adipic acid polyester plasticizer and a dialkyl adipate plasticizer. Has a break strength equal to or better than that of film.

  Moreover, elongation rate (or stretch property) can be improved more by increasing the total amount of the plasticizer (A) and the plasticizer (B) contained in the polyvinyl chloride stretch film. Even if such a polyvinyl chloride stretch film is as thin as about 10 μm, the maximum elongation at break in the TD direction is as high as 400% or more. For this reason, a food container automatic packaging machine having a draw ratio of about 232 times in the width direction of the film, for example, AW-3600 manufactured by Teraoka Seiko Co., Ltd. also exhibits good packaging machine suitability.

３）可塑剤（Ｃ）
エポキシ化大豆油：(株)ダイセル化学工業製 製品略号：ＥＳＢＯThe vinyl chloride resins and plasticizers used in the examples and comparative examples are shown below.
1) Vinyl chloride resin T-1000 vinyl chloride homopolymer manufactured by Taiyo PVC Co., Ltd. TH-1300 [ethylene-vinyl chloride copolymer (ethylene 5 mol%)] manufactured by Taiyo PVC Co., Ltd.
2) Plasticizer (A)
Diisononyl adipate (JPLUS, Inc., product name: DINA)
Mixture of hexyl adipate, octyl adipate and decyl adipate (J-PLUS, product name: D610A)
3) Plasticizer (B)
Triethylene glycol compound represented by the following formula, which constitutes diester with benzoic acid and 2-ethylhexylic acid [manufactured by LG Chemical Co., Ltd. (Korea), brand name: LGflex EBN. W, weight average molecular weight 388]

3) Plasticizer (C)
Epoxidized soybean oil: manufactured by Daicel Chemical Industries, Ltd. Product code: ESBO

1. Stretch film for push-up type automatic packaging machine (Example 1)
100 parts by weight of vinyl chloride resin (T-1000 manufactured by Taiyo PVC Co., Ltd.), 10 parts by weight of diisononyl adipate (J Plus, product name: DINA) as a plasticizer (A), plasticizer (B ) 18 parts by weight of a triethylene glycol compound (manufactured by LG Chemical Co., Ltd., Korea) Brand name: LGflex EBN.W, and 10 parts by weight of epoxidized soybean oil (J. , Product name: ESBO), 1.0 part by weight of Ca-Zn stabilizer, 1.5 parts by weight of polyglycerol fatty acid ester, 1.0 part by weight of sorbitan fatty acid ester, and 1. Further, 0 part by weight of polyoxyethylene alkyl ether was further blended and mixed by heating to obtain a vinyl chloride resin composition. This vinyl chloride resin composition was melt-kneaded at 210 ° C. with a screw in an extruder and then extrusion molded by a T-die method to form stretch films having a thickness of 8 μm and 10 μm, respectively.

(Examples 2 to 7)
Stretch films having a thickness of 8 μm and 10 μm were formed in the same manner as in Example 1 except that the type and content of the plasticizer were changed as shown in Table 1.

(Comparative Example 1)
Stretch films having a thickness of 8 μm and 10 μm were formed in the same manner as in Example 1 except that the plasticizer (B) was not blended and the type and content of the plasticizer were changed as shown in Table 1.

  Tensile properties of the stretch films obtained in Examples 1 to 7 and Comparative Example 1; specifically, the breaking strength in the TD direction and the maximum elongation at break of the films were evaluated by the following methods. These results are shown in Table 1.

Tensile properties (maximum elongation at break and break strength)
Using the tensile tester UCT-500 manufactured by Orientec Co., Ltd., when the No. 2 test piece (10 mm × 100 mm) was pulled in the TD direction of the film based on JISK7127, the breaking strength and the maximum until the film broke Each elongation was determined. The measurement of the breaking strength and the maximum elongation of the film was carried out under conditions of a temperature of 23 ± 2 ° C. and a tensile speed of 500 mm / min.

  As shown in Table 1, each of the stretch films of Examples 1 to 7 has high breaking strength and relatively good maximum elongation at break even when the film thickness is as thin as 8 to 10 μm. I know that there is. Specifically, it can be seen that when the film thickness is 10 μm, the breaking strength in the TD direction is as high as 1.85 N / cm or more, and the maximum elongation at break is 286% or more, which is equal to or more than the conventional one. It can be seen that when the film thickness is 8 μm, although there is some variation, the breaking strength in the TD direction is generally as high as 1.48 N / cm or more, and the maximum elongation at break is 248% or more.

  On the other hand, the stretch film of Comparative Example 1 has a low breaking strength when the film thickness is as thin as 8 to 10 μm. Specifically, it can be seen that the breaking strength in the TD direction when the film thickness is 10 μm is as low as 1.69 N / cm, and the breaking strength in the TD direction when the film thickness is 8 μm is as low as 1.16 N / cm.

  In the stretch films of Examples 1 to 4 having a film thickness of 8 μm, the breaking strength in the TD direction tends to increase as the blending ratio of the plasticizer (B) / plasticizer (A) increases. The same tendency is observed in the stretch films of Examples 5 to 7 having a film thickness of 10 μm.

2. Film for high stretch type automatic packaging machine (Example 9)
100 parts by weight of vinyl chloride resin [ethylene-vinyl chloride copolymer (ethylene 5 mol%) Taiyo PVC Co., Ltd. TH-1300], 10 parts by weight of diisononyl adipate (A1) as plasticizer (A), plastic 22 parts by weight of a triethylene glycol compound [manufactured by LG Chemical Co., Ltd., Korea) Brand name: LGflex EBN. W, average molecular weight 388], and 15 parts by weight of epoxidized soybean oil [Daicel Chemical Industries, Ltd., product abbreviation: ESBO] as a plasticizer (C), and 1.0 part by weight of a Ca-Zn stabilizer. Further, 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 were further added and mixed by heating to prepare a vinyl chloride resin composition. Got. This vinyl chloride resin composition was screw kneaded with an extruder and melt-extruded from a T die at about 210 ° C. As a result, films having a thickness of 12 μm, 10 μm, and 8 μm were formed. The obtained film was wound up into a roll having a width of 300 mm by a drawing winder.

(Examples 10 to 14)
A stretch film was formed in the same manner as in Example 9 except that the plasticizer content was changed as shown in Table 2.

(Comparative Examples 2-7)
A stretch film was formed in the same manner as in Example 9 except that the plasticizer content was changed as shown in Table 3.

  The tensile properties, hue, and packaging machine properties of the stretch films obtained in Examples 9 to 14 and Comparative Examples 2 to 7 were evaluated as follows. These results are shown in Tables 2 and 3.

1) Tensile properties (maximum elongation at break and break strength)
Using a tensile tester UCT-500 manufactured by Orientec Co., Ltd., the breaking strength until the film breaks when a No. 2 test piece (10 mm × 100 mm) is pulled in the TD direction of the film based on JIS K7127 And the maximum elongation were obtained respectively. The measurement of the breaking strength and the maximum elongation of the film was carried out under conditions of a temperature of 23 ± 2 ° C. and a tensile speed of 500 mm / min.

2) Hue The hue of the stretch film wound in a roll shape was evaluated by visual sensation.
○: Good ×: Bad (dull color)

3) Suitability for packaging machine Peelability Evaluation was made on the state of slipping, slipping, loosening, and the like when pulled out from a roll-shaped wound body.
◯: Good without causing problems Δ: Some problems ×: Difficult to pull out, slipping, problems such as roll end gradually breaking Cut property The cut property of the film at the time of machine packaging was evaluated.
◯: Cut well x: Cut is not smooth Wrinkles were evaluated for the presence or absence of wrinkles generated from the roll or on the film surface of the package.
○: Wrinkle is not generated ×: Wrinkle is generated in the packaging depression, and it is not smoothly pulled out, and wrinkle is generated.
○: Never come out ×: Easily comes off and causes poor packaging ○: Overall evaluation of suitability of packaging machine ○: Good △: Somewhat lacking in applicability ×: There is a problem

  As shown in Tables 2 and 3, it can be seen that the stretch films of Examples 9 to 14 have higher tensile elongation than the stretch films of Comparative Examples 2 to 6 while having good packaging machine characteristics. In particular, the maximum elongation at break in the TD direction of the film increases as the total amount of the plasticizer (A) and the plasticizer (B) increases, and as the weight ratio of the plasticizer (A) / plasticizer (B) increases. It turns out that it becomes high.

  This application claims the priority based on Japanese Patent Application No. 2009-190766 of an application on August 20, 2009. All the contents described in the application specification are incorporated herein by reference.

  The polyvinyl chloride stretch film of the present invention has a high breaking strength and an appropriate elongation even at a thin film thickness. For this reason, the polyvinyl chloride-based stretch film is particularly suitable for packaging food storage containers using a push-up type automatic packaging machine or a high stretch type automatic packaging machine.

Claims (8)

100 parts by weight of vinyl chloride resin,
Adipic acid dialkyl ester plasticizer (A1) which is a reaction product of adipic acid and an aliphatic alcohol having an alkyl group having 6 or more carbon atoms, and an adipic acid polyester plasticizer (A2) having a weight average molecular weight of 1000 to 3000 0 to 15 parts by weight of one or more plasticizers (A) selected from the group;
10 to 30 parts by weight of a plasticizer (B) composed of a triethylene glycol compound that forms a diester by dehydration condensation reaction between hydroxyl groups at both ends of the molecule and each of benzoic acid and 2-ethylhexylic acid;
10 to 20 parts by weight of a plasticizer (C) made of epoxidized vegetable oil, and a total amount of the plasticizer (A) and the plasticizer (B) is 20 to 35 parts by weight. A polyvinyl chloride stretch film comprising the composition.   The polyvinyl chloride stretch film according to claim 1, wherein the plasticizer (A) is diisononyl adipate.   The polyvinyl chloride stretch film according to claim 1, wherein the plasticizer (A) / the plasticizer (B) is 0.65 or less by weight. The polyvinyl chloride stretch film according to claim 1, wherein the triethylene glycol compound is represented by the following formula.

100 parts by weight of vinyl chloride resin,
8 to 32 parts by weight of adipic acid dialkyl ester plasticizer (A1), which is a reaction product of adipic acid and an aliphatic alcohol having an alkyl group having 6 or more carbon atoms,
8 to 32 parts by weight of a plasticizer (B) comprising a triethylene glycol compound constituting a diester by dehydration condensation reaction between hydroxyl groups at both ends of the molecule and benzoic acid and 2-ethylhexylic acid;
10-20 parts by weight of a plasticizer (C) made of epoxidized vegetable oil, and a total amount of the plasticizer (A1) and the plasticizer (B) is 28-42 parts by weight. A polyvinyl chloride stretch film comprising the composition.   The polyvinyl chloride stretch film according to claim 5, wherein the plasticizer (A1) is diisononyl adipate. The polyvinyl chloride stretch film according to claim 5, wherein the triethylene glycol compound is represented by the following formula.

  The polyvinyl chloride stretch film according to claim 5, wherein the plasticizer (A1) / the plasticizer (B) is 0.8 or more by weight.