JP5230349B2 - Vinyl chloride resin stretch film - Google Patents

Description

  The present invention relates to a vinyl chloride resin stretch film for safe food packaging that does not contain an environmental hormone substance, and more particularly, to a vinyl chloride resin stretch film excellent in packaging suitability by an automatic packaging machine for stretching.

In the food packaging field of fresh foods such as fruits and vegetables, fresh fish, and meat, stretch films having excellent transparency, stretchability (flexibility), heat sealing, and the like are used.
Usually, a stretch film is made of a vinyl chloride-based tree composition using an adipic acid ester or a glycerin fatty acid ester and an epoxidized vegetable oil as a plasticizer in a vinyl chloride resin such as a vinyl chloride polymer or a vinyl chloride copolymer. It is manufactured by film formation by extrusion molding such as T-die method.

However, since azibic acid esters used as plasticizers are unclear about the problem of environmental hormones, glycerin fatty acid esters are mainly used avoiding azibic acid esters. A thermoplastic resin composition using a glycerin fatty acid ester in a predetermined blending amount has been proposed (for example, see Patent Document 1).
This thermoplastic resin composition comprises 35 parts by weight of glycerin fatty acid ester, 10 parts by weight of epoxidized soybean oil, 2 parts by weight of a Ca-Zn stabilizer, and 0.5 parts by weight of a chelator based on 100 parts by weight of a vinyl chloride resin. As an antifogging agent, 1.0 part by weight of sorbitan laurate / 1.0 part by weight of polyoxyethylene alkyl ether is blended.
Japanese Examined Patent Publication No. 3-35331 (Refer to page 4, right column, lines 17 to 27)

  By the way, in the said patent document 1, the chelator mix | blended as a stabilizer with respect to thermal decomposition has a problem in safety. In other words, in this kind of food packaging field, the chelator is phosphite (phosphite) and trisnonylphenyl phosphite. This trisnonylphenyl phosphite is a decomposition product of nonylphenol as a so-called environmental hormone substance. There was a safety problem.

In the food packaging field in recent years, with the spread of prepackage packaging, stretch films that are used in large quantities as food packaging films for meat, fresh fish, fruits and vegetables, etc. are stretched to improve packaging speed and save labor. While the packaging by the automatic packaging machine is rapidly increasing, the stretch film formed using the thermoplastic resin composition described in Patent Document 1 is not suitable for packaging by the automatic packaging machine for stretching.
In other words, in addition to the properties required for food packaging, such as transparency, anti-fogging properties, and freshness retention, the vinyl chloride resin stretch film used in the automatic packaging machine for stretching is an automatic stretching machine. Packaging suitability is required.
This packaging suitability means that the film is smoothly drawn out when the film is pulled out (disassembled) from the film roll, and the slipperiness with the package is good, and the package is firmly secured without tearing the film. Further, it refers to the characteristic (performance) that a packaged product can be packaged without peeling off over time due to self-adhesiveness.

The present invention has been developed to solve such problems, and it is an object of the present invention to provide a highly safe vinyl chloride resin stretch film that does not contain an environmental hormone substance.
Moreover, in the present invention, transparency required for an automatic packaging machine for stretching, smooth unfolding and stretching, excellent overlap property in which films overlap each other, and further, packaging without tearing can be achieved. It is providing the vinyl chloride-type resin stretch film which has the characteristic of.

  As a result of intensive studies over many years in order to achieve the above-mentioned problems, the present inventors have found that glycerin fatty acid esters and epoxidized vegetable oils with higher safety are used as plasticizers, and calcium salts of oleic acid and ricinoleic acid and / or Or a mixture of calcium salt of benzoic acid and zinc salt of oleic acid and / or ricinoleic acid, and further epoxidized soybean oil or epoxidized linseed oil and heating to obtain a heated solution and tridecyl poly Oxyethylene (4 to 10) phosphoric acid is added with phosphoric acid or phosphorous acid and heated, and a mixture consisting of a heated melt is used as a stabilizer. It turned out that the stretch film suitable for the packaging by the automatic packaging machine for extending | stretching is obtained by mix | blending with a vinyl resin.

That is, the present invention
(A) 30 parts by weight of glycerol fatty acid ester and 10 to 20 parts by weight of epoxidized vegetable oil, 100 parts by weight of vinyl chloride resin having a polymerization degree of 1300 to 1450, (C) calcium salt of oleic acid and ricinol A heated melt obtained by adding a zinc salt of oleic acid and / or ricinoleic acid to a mixture of a calcium salt of acid and / or benzoic acid, and further adding epoxidized soybean oil or epoxidized linseed oil, followed by heating; Tridecyl polyoxyethylene (4 to 10) phosphoric acid, a mixture 0.05 comprising a resin composition in which 0.001 to 1 part by mass of a heated melt obtained by adding phosphoric acid or phosphorous acid and heating is added 0.05 It is in the vinyl chloride-type resin stretch film characterized by consisting of a resin composition which mix | blended -1.5 mass part.
Here, the glycerol fatty acid ester, it is suitable is glycerin diacetic preparative monolaurate. Moreover, it is suitable that the unwinding force of the film is 200 to 500 g per 350 mm of film width.

  According to the present invention, it is highly safe not to contain an environmental hormone substance, and it is excellent in smooth unwinding force and stretchability required as a film for an automatic packaging machine for stretching, and excellent overlap property in which films overlap each other. Furthermore, it is possible to provide a vinyl chloride resin stretch film having characteristics such as being able to be firmly packaged without tearing.

  The vinyl chloride resin composition of the stretch film of the present invention comprises a component (B) glycerin fatty acid ester and an epoxidized vegetable oil, and a component (C) oleic acid calcium salt with respect to the component (A) vinyl chloride resin. To the mixture of calcium salt of ricinoleic acid and / or benzoic acid with the addition of oleic acid and / or zinc salt of ricinoleic acid, and then epoxidized soybean oil or epoxidized linseed oil and heating to dissolve And a mixture of a heated solution obtained by adding phosphoric acid or phosphorous acid to tridecyl polyoxyethylene (4-10) phosphoric acid and heating.

  In the vinyl chloride resin composition of the stretch film of the present invention, the vinyl chloride resin used as the component (A) is a polyvinyl chloride polymer obtained by suspension polymerization.

As the plasticizer of the component (B) blended in the vinyl chloride resin of the component (A), a glycerin fatty acid ester and an epoxidized vegetable oil are used in combination.
Glycerol fatty acid esters are known as non-toxic plasticizers, esters of glycerin acetate and fatty acid are preferred, especially, glycerol Zia Seto monolaurate is preferred.
Epoxidized vegetable oils are also known as non-volatile and stabilizer-free low-volatility, low-extractable plasticizers such as epoxidized soybean oil, epoxidized linseed oil, and epoxidized linseed oil fatty acid butyl. Used.

The compounding quantity of a component (B) is 30-45 mass parts with respect to 100 mass parts of vinyl chloride-type resin, Preferably it is 35-40 mass parts. The epoxidized vegetable oil is 10 to 20 parts by mass. Since this epoxidized vegetable oil has a problem in cold resistance and compatibility, 15-18 mass parts is preferable.
And in order to make softness suitable for the stretch film for food packaging by the automatic packaging machine for extending | stretching, the total compounding quantity of a plasticizer is 40-60 mass parts with respect to 100 mass parts of vinyl chloride resin, Preferably It is 45-55 mass parts. When it is 40 parts by mass or less, the stretchability when drawn from the film roll by the automatic packaging machine for stretching (disassembled) and stretched in the width direction is poor.

  In addition to the above, other non-toxic plasticizers can be used in combination as the plasticizer of component (B).

In the present invention, component (C) is a stabilizer.
Component (C) is a mixture of a calcium salt of oleic acid and a calcium salt of ricinoleic acid and / or benzoic acid with a metal soap added with a zinc salt of oleic acid and / or ricinoleic acid, and further epoxidized soybean oil or epoxidized (C2) obtained by adding phosphoric acid or phosphorous acid to the heated melt of (C1) obtained by adding linseed oil and heating, and tridecylpolyoxyethylene (4-10) phosphoric acid. It is a mixture comprising a heated melt. These metal soaps may be acidic salts or neutral salts.
The compounding quantity of the component (C) which consists of a mixture of (C1) and (C2) is 0.05-2.5 mass parts with respect to 100 mass parts of vinyl chloride resin. This is because if the blending amount is 0.05 parts by mass or less, the thermal stability effect is not sufficient, and if it is 2.5 parts by mass or more, it is easy to cause a brate-out or a discoloration, and the transparency of the formed film is likely to deteriorate. . A more preferable blending amount is 0.08 to 1.5 parts by mass.
The heating temperature is preferably in the temperature range of 50 to 120 ° C.

Moreover, in this invention, in addition to above-described component (A)-(C), the antifogging agent of a component (D) can be selectively selectively mix | blended.
Anti-fogging agents for this component (D) include glycerin fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, fatty acid alkylolamides, and more specifically, diglycerol laurate monooleate, oleic acid monoglyceride Sorbitan monolaurate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene sorbitan monolaurate, di- (2-hydroxyethyl) alkylamine, polyoxyethylene alkyl ether and the like.
Here, the glycerin fatty acid ester-based antifogging agent has the property of imparting slipperiness to the film and lowering the anti-repulsive force, while sorbitan fatty acid ester-based, polyoxyethylene sorbitan fatty acid ester-based, fatty acid alkyl. The roll amide antifogging agent has the property of imparting resistance to slippage and increasing the anti-reaction force, and therefore can be prepared by appropriately blending both antifogging materials.
The compounding quantity of this component (D) is 1.0-2.5 mass parts with respect to 100 mass parts of vinyl chloride resin. If the blending amount is 1.0 part by mass or less, the anti-fogging effect for preventing moisture contained in the package from condensing on the film surface and clouding is insufficient, and if the blending amount is 2.5 parts by mass or more, the slip of the film Increases and the reaction force decreases. A more preferable blending amount is 1.5 to 2.0 parts by mass.

  As mentioned above, in this invention, the glycerol diacemonolaurate of a component (B) and an epoxidized vegetable oil are used as a plasticizer. The composition containing the components (C) and (D) does not contain an environmental hormone substance and is excellent as a stabilizer for vinyl chloride resins.

The vinyl chloride resin composition of the stretch film of the present invention is prepared by a conventionally well-known preparation method, for example, mixing using the above-mentioned components (A) to (D) and various blending components as required, such as a mixer or a kneader. -It can be prepared by kneading.
The vinyl chloride resin composition thus prepared is formed into a stretch film having a film thickness of 10 μm to 15 μm by forming a film by extrusion molding using a conventionally known method such as a T-die method. can do.

And in this invention, in order to apply the stretch film obtained in this way to the automatic packaging machine for extending | stretching, it is suitable that the reaction force of a film shall be 200-500g per 350 mm of film widths. When this unwinding force is less than 200 g, gripping is made up of an endless belt or the like that grips both side edges of the film when it is stretched in the width direction according to the size (length) of the tray container in which the objects to be packaged are placed and stored. This is because the film tends to come off from the tool, and if it exceeds 500 g, the film sticks to the gripping tool, and it is difficult to continue the packaging operation after being pulled out (unbound) from the film roll. The preferred reaction force is 250 to 400 g. This anti-repulsive force can be prepared according to the type and blending amount of the antifogging agent of component (D) described above.
This is particularly effective when the film is stretched in the width direction by a stretching automatic packaging machine equipped with a stretching machine having a gripping tool made of an endless belt made of polyurethane or the like.

EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited at all by these Examples.
[Examples 1-12 and Comparative Examples 1-10]
As the component (A), vinyl chloride resins having a degree of polymerization of 1100, 1300, 1450, and 1700 are used, and 100 parts by mass of each of these vinyl chloride resins is used as a plasticizer and the glycerin diacetate monolaur of component (B). Rate (manufactured by Riken Vitamin) and epoxidized soybean oil, as stabilizer, a mixture of (C1) 25% by mass and (C2) 35% by mass of component (C) (commercially available as No. 9505 from Akishima Chemical Co., Ltd.) As an antifogging agent, 50% of sorbitan laurate of component (E) and 50% of ethylene alkyl ether, these blending components are blended in the blending ratios (parts by mass) shown in Table 1 and Table 2, respectively. After mixing and kneading to prepare a vinyl chloride resin composition, each vinyl chloride resin composition is formed into a film with a film width of 3 by extrusion molding such as the T-die method. In 0 mm, film thickness was produced respectively stretch film 13 .mu.m.
And the physical property was evaluated with the following method about each stretch film which uses as a main raw material each vinyl chloride-type resin of polymerization degree 1100, 1300, 1450, 1700 obtained in this way. The evaluation results are shown in Table 1 and Table 2, respectively.

[Transparency of film]
Using a haze meter, one film is measured and the measured value is shown. The transparency appropriate haze value is 3% or less, and 3% or more is unsuitable.

[Packaging is appropriate]
Evaluation 1: Unwinding force The unwinding force is set at a speed of 500 mm / min using a strut-type or autograph-type tensile tester by setting a film with a width of 350 mm on a dedicated jig (unscrewing machine). And measure. The change with time of the tensile strength applied at the time of the dissolution is charted. The solution begins when a certain tension is applied, and once the solution begins, the strength of the tension appears over time. When this is shown in the graph, it becomes a curve having continuous peaks and valleys. In this example, the value obtained when the tension was increased while being pulled out (dissolved) by 500 mm, that is, the average value of the values at the vertices of the peaks in the graph was used as the solution force. In addition, what is not 350 mm in width is converted into 350 mm width after a measurement.
Evaluation 2: Overlap This overlap consists of a PP tray container that is marketed with meat, fresh fish, and other items to be wrapped, and continuously wrapped with a Teraoka Seiko stretch wrapping machine “AW4600”. Evaluation was performed in four stages (evaluation was made with the width at which the films at the bottom of the tray container overlap).
a. Widely overlapped part can be tightly packed: ○
b. Slightly narrow overlapped portion but can be packaged: △
c. Overlapping width is narrow and unsuitable for packaging: ×
d. Not suitable for packaging without overlapping parts: XX
Evaluation 3: Breaking As with the overlap evaluation described above, this tearing was repeated by Teraoka Seiko's stretch wrapping machine “AW4600” and evaluated in four stages according to the following criteria (the film includes the packaged items) The film was evaluated for tearing until reaching a packaging form in which the tray container was completely wrapped.
a. Good packaging without tearing: ○
b. What can be packaged with 30% of tears: △
c. Wrapped in 50% but can be packaged: ×
d. Everything is broken and unsuitable for packaging: XX

[Extrudability]
In this example, as shown in Tables 1 and 2, the moldability when each of the vinyl chloride resin compositions is extruded by the T-die method is divided into two stages under the following processing conditions. And evaluated.
Processing conditions:
a. Temperature: Extruder C1: 170 ° C, C2: 190 ° C, C3: 190 ° C, Die
190 ° C
b. Discharge rate: 300kg / Hr
c. Film take-off speed: 150 m / min
d. Cooling condition: blows cooling air with cooling air blower temperature of 25 ℃
e. Film thickness: 13μm
Rating:
a. Can be produced without discoloration or burning during processing: ○
b. Difficult to process due to film discoloration or burning: ×

As is clear from Table 1, the stretch film for food packaging of the present invention (Examples 1 to 12) passed all of transparency (haze), packaging suitability (dissolution force, overlap, tear), and extrusion processability. However, the stretch film (comparative examples 1-10) of a comparative example is any one or more and is disqualified.
Thus, the stretch film for food packaging of the present invention is excellent in packaging suitability and extrusion processability in addition to the properties such as transparency, antifogging property, and freshness retention required as a film for an automatic stretch packaging machine. I understand that.

Claims (2)

(A) For 100 parts by mass of a vinyl chloride resin having a degree of polymerization of 1300 to 1450,
(B) 30-45 parts by mass of glycerin diacetomonolaurate and 10-20 parts by mass of epoxidized vegetable oil,
(C) To a mixture of a calcium salt of oleic acid and a calcium salt of ricinoleic acid and / or benzoic acid, oleic acid and / or a zinc salt of ricinoleic acid is added, and then epoxidized soybean oil or epoxidized linseed oil is added. 0.05-1 of a mixture consisting of a heated lysate obtained by heating and heated and obtained by adding phosphoric acid or phosphorous acid to tridecyl polyoxyethylene (4-10) phosphoric acid and heating. .5 parts by mass,
A vinyl chloride resin stretch film comprising a resin composition containing The vinyl chloride resin stretch film according to claim 1, wherein the reaction force of the vinyl chloride resin stretch film according to claim 1 is 200 to 500 g per 350 mm of film width .