JPH0788973A - Manufacture of polyvinyl chloride stretch film - Google Patents

Abstract

PURPOSE:To provide a stretch film, in a shortened manufacturing process, improving the production efficiency and packing property, by a method wherein polyvinyl chloride resin composition is extruded under the predetermined condition of humidity and, subsequently, the film is wound up under the predetermined temperature condition of the film. CONSTITUTION:A polyvinyl chloride stretch film is prepared by a method wherein polyvinyl chloride resin composition is extruded under the atmosphere of absolute humidity of 0.014-0.023kg/m<3> and, subsequently, the film is wound up within the temperature range of 35-45 deg.C of film temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyvinyl chloride stretch film having excellent packaging suitability.

[0002]

2. Description of the Related Art Polyvinyl chloride-based stretch films are used in large quantities in pre-packaging of foods such as meat, fresh fish, fruits and vegetables and prepared foods. for that reason,
In recent years, it has been required to improve the packaging speed and save labor, and the number of methods using an automatic packaging machine is rapidly increasing. In general, stretch films used in automatic packaging machines require the suitability for automatic packaging machines in addition to the performance such as transparency, anti-fog property, and freshness retention that are required for food packaging. . This wrapping suitability means that the film is smoothly fed out from the film winding body, has good slidability with the object to be packaged (especially food tray), and securely wraps the object to be wrapped without breaking the film. Further, the self-adhesive property refers to the ability to package a packaged object without the packaged film peeling off over time. Various methods have been proposed as methods for imparting such packaging suitability. For example, a method of blending a large amount of antifogging agent (Japanese Patent Publication No. 52-1743), a method of leaving a soft polyvinyl chloride film wound on a roll and left in an atmosphere of 35 to 50 ° C. for at least 24 hours. (Japanese Patent Laid-Open No. 50-655
No. 63), a method of aging a formed film under high temperature and high humidity (Japanese Patent Laid-Open No. 59-213749), and the like. Also, as a method for quantitatively grasping the packaging suitability given to the film, the value of the winding peel stress is 400 ~
There is known a method (Japanese Patent Publication No. 1-57696) for determining the suitability of packaging by setting the range to 700 g.

However, the method (1) has a drawback that the transparency of the film is impaired by the bleed-out component of the antifogging agent mixed in a large amount and the commercial value is lowered. Also,
In the method (1), it is impossible to impart packaging suitability unless the film once formed is left to stand or aged, and in order to do this, a wide space and accompanying equipment are required. Furthermore, to leave or age it,
Since it takes 24 to 72 hours, there is a problem that the time loss is large and the production efficiency is low. Furthermore, in the method, the molding conditions are not specified, and only the quality of the molded film is determined, and good packaging suitability is imparted if the film peeling reaction is within the specified range. However, outside of the specified range, they all became defective and the loss was large.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art. By defining the molding conditions and film winding conditions, the quality of products can be controlled and the film manufacturing process can be shortened. Moreover, it is an object of the present invention to provide a method for producing a polyvinyl chloride stretch film, which can stably provide a stretch film having excellent packaging suitability.

[0005]

As a result of intensive studies conducted by the inventor in view of the above problems, a method for quantitatively grasping the suitability for packaging by specifying the range of the winding peel stress (Patent Document 1) 1-57696) further developed, by winding the film under certain conditions, it is possible to specify the amount of film peeling off from the film winding body within a certain range, It was found that the superiority or inferiority of packaging suitability can be judged by the range.

[0006] This film winding peeling amount means that a round bar is inserted into the hollow of the paper tube of a film winding body having a width of 300 mm and a thickness of 15 µm wound around the paper tube, while the film end of the film winding body is inserted. It shows the length of the film that is peeled from the roll in 1 minute by applying a weight of 100 g to the part, and the peeling amount is in the range of 1,000 to 1,500 mm (1 m to 1.5 m / min). , The packaging suitability was found to be particularly good.

As a result of repeated studies, the inventor carried out film extrusion in an atmosphere of absolute humidity within a certain range,
Then, by winding this film at a film temperature within a certain range, it was possible to specify the peeling amount within the above range, and it was found that the above problems can be solved, and the present invention was completed.
That is, the present invention is characterized in that the polyvinyl chloride resin composition is extruded under an atmosphere of absolute humidity 0.014 to 0.024 kg / m ³ , and then this film is wound in a temperature range of 35 to 45 ° C. A method for producing a polyvinyl chloride stretch film. Hereinafter, the present invention will be described in detail.

The polyvinyl chloride resin used in the stretch film of the present invention is a vinyl chloride homopolymer or a copolymer mainly composed of vinyl chloride, which is a monomer copolymerizable with vinyl chloride, such as acetic acid. vinyl,
Examples thereof include copolymers with vinylidene chloride, diethyl maleate, ethylene, propylene and the like. These vinyl chloride resins are those obtained by a conventionally known polymerization method such as emulsion polymerization, suspension polymerization, solution polymerization, and bulk polymerization,
Either may be used.

The polyvinyl chloride resin composition used in the present invention is obtained by optionally blending the above-exemplified resin with a plasticizer, a stabilizer, a lubricant, an antifogging agent and the like. Examples of the plasticizer blended in the polyvinyl chloride resin composition include di-i-butyl adipate, di-n-butyl adipate, di-i-nonyl adipate, dioctyl adipate, and di-n sebacate. -Aliphatic dibasic acid esters such as butyl; hydroxy polyvalent carboxylic acid esters such as tributyl acetyl citrate, triethyl acetyl citrate, tri-2-ethylhexyl acetyl citrate; methyl acetyl linoleate, methyl palmitate, stearin Aliphatic esters such as methyl acidate, -n-butyl stearate, butyl oleate; di-n-butyl phthalate, dihexyl phthalate, dioctyl phthalate, butylbenzyl phthalate, -n-octyl phthalate-n- Phthalates such as decyl; pentaerythritol esters, die Glycol esters such as len glycol benzoate; phosphoric acid esters such as tricresyl phosphate and triphenyl phosphate; epoxidized oils such as epoxidized soybean oil and epoxidized linseed oil; trialkyl trimellitate, tetra-n- Examples include octyl pyromellitate, polypropylene adipate, and other polyester plasticizers, and these are used alone or in combination of two or more.

As the stabilizer compounded in the polyvinyl chloride resin composition, Ca-Zn higher fatty acid salt is used, for example, 2-ethylhexylic acid, benzoic acid, isodecanic acid, citric acid, sorbic acid and the like. Examples thereof include calcium salts of higher fatty acids and zinc salts of higher fatty acids such as 3-ethylhexylic acid, isodecanoic acid and neodecanoic acid, and these are used alone or in combination of two or more.

As the lubricant to be blended, a mixed ester of a polyhydric alcohol having 2 to 20 carbon atoms, a higher fatty acid having 11 to 20 carbon atoms and a saturated dibasic acid having 4 to 6 carbon atoms is used. It The component ratio of the higher fatty acid and the saturated dibasic acid in the mixed ester is preferably in the range of 1 to 2 mol of the saturated dibasic acid with respect to 6 to 12 mol of the higher fatty acid because the lubricity is stable. 2 carbon atoms used in the above mixed ester
Examples of the polyhydric alcohols of up to 20 include sorbitan, sorbitol, glycerin, polyglycerin, pentaerythritol, dipentaerythritol, propylene glycol and diethylene glycol, and they are used alone or in combination of two or more. . As the higher fatty acid having 11 to 20 carbon atoms, lauric acid, myristic acid, undecanoic acid, tridecanoic acid, pentadecanoic acid, palmitic acid, stearic acid, margaric acid, isostearic acid, 12-hydroxystearic acid, oleic acid, linoleic acid , Ricinoleic acid, linoleic acid, n-heneiic acid, phenic acid, n-tricoic acid, arachidonic acid and the like, and these are used alone or in combination of two or more. Further, examples of the saturated dibasic acid having 4 to 6 carbon atoms include adipic acid, succinic acid and glutamic acid, and these are used alone or in combination of two or more.

As the anti-fogging agent to be blended with the polyvinyl chloride resin composition, polyglycerin fatty acid ester,
Examples thereof include sorbitan acid ester, polyoxyethylene fatty acid alcohol ether, and polyoxyethylene alkylphenyl ether, which are used appropriately.

According to the method of the present invention, the polyvinyl chloride resin composition is extruded in an atmosphere having an absolute humidity of 0.014 to 0.024 kg / m ³ , and then the film is heated to a film temperature of 35 to 45 ° C.
It is characterized by winding in the temperature range of. The pass length of the extrusion process for controlling the absolute humidity within the above range is preferably the entire film within the range of 1 m in the film flow direction from the die surface. This absolute humidity is 0.014 to 0.024
If it is less than kg / m ³ , the amount of water adhering to the film surface will be insufficient and the peeling amount will not reach 1,000 mm. In this case,
Although the self-adhesiveness of the film is excellent, the slipperiness of the object to be packaged is insufficient, causing a problem that the film breaks during packaging. Also, if the absolute humidity exceeds 0.024 kg / m ³ , the amount of water adhering to the film surface will be excessive, and
It exceeds 00 mm. In this case, the lubricity with the object to be packaged is good, but the self-adhesiveness is lowered, and the problem that the packaged film peels off with time occurs. Therefore, only when the absolute humidity is within the above range, a film having excellent smoothness and self-adhesiveness on the film surface can be obtained.

The point where the film temperature is measured during winding is the entire film within a range of up to 30 cm in the direction opposite to the film flow direction, from the contact point between the paper tube for winding the film of the winder and the film to be wound. preferable. A non-contact surface thermometer is used for this measurement. The film temperature during winding is 35
If the temperature is lower than ℃, the film becomes hard, which causes the air layer to be entrained between the films of the film roll, and this air layer increases the amount of roll peeling, and the roll peel amount exceeds 1,500 mm. . In this case, the pay-out of the film is smooth, but the self-adhesiveness is insufficient. On the other hand, if the film temperature is higher than 45 ° C, the film is soft and blocking is likely to occur, the adhesion between the films of the film winding body becomes strong, and the peeling amount of the film does not reach 1,000 mm. In this case, the film is not smoothly delivered from the film winding body. Therefore, only when the film temperature is in the above range, the film can be smoothly fed out from the film winding body and excellent in self-adhesiveness.

The film peeling condition is satisfied only when the film is produced within the range of the humidity condition and the film temperature condition described above, the film is smoothly unwound from the film winding body, and the sliding property with the object to be packaged is good. It is possible to obtain a film that is good and has excellent self-adhesiveness.

The polyvinyl chloride resin composition used in the present invention comprises a polyvinyl chloride resin exemplified above with a plasticizer, a lubricant, an antifogging agent and the like, if necessary, and a mixer such as a Henschel mixer. It is obtained by uniformly mixing by using a known method. As a method for molding the polyvinyl chloride resin composition into a film, a known extrusion molding process such as a T-die method or an inflation method may be adopted. Usually, the width is about 200 to 600 mm and the thickness is 15 to 20 μm.
It is formed into a film of a certain degree and wound on a paper tube or the like.

[0017]

According to the method of the present invention, the quality of the film can be controlled by extruding the polyvinyl chloride resin composition under the humidity conditions exemplified above, and then winding this film under the above film temperature conditions. Can shorten the manufacturing process without leaving or aging after film formation,
Furthermore, when the amount of peeling off the roll is too small, the film is not smoothly fed from the film winding body, the trouble that the film is torn due to insufficient slippage with the object to be wrapped, and the amount of peeling off the roll is too large. It is possible to solve the problem that the product to be packaged cannot be packaged properly and the problem that the packaged film peels off with time due to its weak self-adhesiveness.

[0018]

EXAMPLES The present invention will be described with reference to examples, but the present invention is not limited to these examples.

(Examples 1-5, Comparative Examples 6-9) (Polyvinyl chloride resin composition blending amount) Polyvinyl chloride resin (average degree of polymerization: 1,000) 100 parts by weight Plasticizer (di-i-nonyl adipate) 35 parts by weight Epoxidized soybean oil 10 parts by weight Stabilizer (Ca-Zn higher fatty acid salt) 1 part by weight Lubricant (isostearic acid) 0.5 parts by weight Anti-fog agent (polyglycerin fatty acid ester) 2.5 parts by weight ) Attach a weight of 100g to the film end of the roll made of a film with a width of 300mm and a thickness of 15μm.
The length of the film peeled off in 1 minute was measured.

After kneading the composition having the above composition with a Henschel mixer, it was extruded and wound by the T-die method under each condition shown in Table 1 to obtain a width of 300 mm and a thickness of 15 μm.
Film was wound on a paper tube. The amount of roll peeling of the obtained film roll was measured by the following method and was as shown in Table 1. In the table, Experiment Nos. 1 to 5 are examples of the present invention, and Nos. 6 to 9 are comparative examples.

When the packaging suitability of the films shown in the examples and comparative examples was confirmed by an automatic packaging machine SP-600 manufactured by Ibaraki Seiki, the films shown in the examples having a winding peeling amount in the range of 1,000 to 1,500 mm Was confirmed to have good packaging suitability. The film shown in the comparative example was insufficient in wrapping suitability due to defective feeding of the film and tearing of the film. (Absolute humidity control range) The entire film within the range of 1 m in the film flow direction from the die surface (Table 1)
The absolute humidity shown in Table 2 was controlled. (Control range of film temperature) The entire film within a range of 30 cm in the direction opposite to the flow direction of the film from the contact point between the paper tube for winding the film of the winder and the film to be wound (Table 1) (Table 2). ) The film temperature was controlled so as to be.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

EFFECTS OF THE INVENTION According to the method of the present invention, a polyvinyl chloride resin composition is extruded under a predetermined humidity condition, and then this film is wound up under a predetermined film temperature condition, so that the manufacturing process can be shortened and the production can be performed. It is possible to provide a stretch film having improved efficiency and good packaging suitability.

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[Procedure amendment]

[Submission date] December 9, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

However, the method (1) has a drawback that the transparency of the film is impaired by the bleed-out component of the antifogging agent mixed in a large amount and the commercial value is lowered. Also,
In the method (1), it is impossible to impart packaging suitability unless the film once formed is left to stand or aged, and in order to do this, a wide space and accompanying equipment are required. Furthermore, since it takes about 24 to 72 hours to leave or mature, time loss is great.
There was a problem of low production efficiency. Furthermore, in the method (1), the molding conditions are not stipulated, and only the quality of the molded film is judged, and if the winding peeling stress of the film is within the specified range, good packaging suitability is obtained. Although they were given, if they were out of the specified range, they all became defective and the loss was large.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

As the lubricant to be blended, a mixed ester of a polyhydric alcohol having 2 to 20 carbon atoms, a higher fatty acid having 11 to 20 carbon atoms and a saturated dibasic acid having 4 to 6 carbon atoms is used. It The component ratio of the higher fatty acid and the saturated dibasic acid in this mixed ester is preferably in the range of 1 to 2 mol of the saturated dibasic acid with respect to 6 to 12 mol of the higher fatty acid, because the lubricity is stable. Examples of the polyhydric alcohol having 2 to 20 carbon atoms used for the mixed ester include sorbitan, sorbitol, glycerin, polyglycerin, pentaerythritol, dipentaerythritol, propylene glycol, diethylene glycol, and the like,
They are used alone or in combination of two or more. Examples of the higher fatty acid having 11 to 20 carbon atoms include lauric acid, myristic acid, undecanoic acid, tridecanoic acid, pentadecanoic acid, palmitic acid, stearic acid, margaric acid, isostearic acid and 1,2-dihydroxy.
Stearic acid , oleic acid, linoleic acid, ricinoleic acid, linolenic acid, n-heneicosanoic acid , peheninic acid, n-tricosanoic acid , arachidonic acid and the like,
These are used alone or in combination of two or more. Further, as the saturated dibasic acid having 4 to 6 carbon atoms,
Adipic acid, succinic acid, glutaric acid and the like can be mentioned, and these can be used alone or in combination of two or more.
Further lubricants include lauric acid, myristic acid, and
Charcoal such as luminic acid, stearic acid, isostearic acid
Higher fatty acid having 8 to 22 elementary atoms; 1,2-dihydroxy
Stearic acid; lauric acid amide, myristic acid
Charcoal such as amide, palmitamide, stearamide, etc.
Higher fatty acid amide having 8 to 22 elementary atoms; Liquid paraffin
Aliphatic hydrocarbons such as hydrocarbons and synthetic paraffins; glycerin
Monoglycols such as propylene and propylene glycol; poly
Such as ethylene glycol and polypropylene glycol
Polyglycols are mentioned, and these are one or more kinds.
Used in the above combination.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

As the anti-fogging agent to be blended with the polyvinyl chloride resin composition, monoglycerin fatty acid ester ,
Polyglycerol fatty acid esters, sorbitan esters, polyoxyethylene fatty alcohol ethers, Po
Lioxyethylene alkyl ether , polyoxyethylene alkyl phenyl ether, etc. are mentioned and used appropriately. As this monoglycerin fatty acid ester,
A saturated or unsaturated fatty acid model having 12 to 18 carbon atoms
A compound selected from the group consisting of noglycerin esters
preferable. Specifically, monoglycerin laurate, mono
Glycerin palmitate, monoglycerin steerer
, Monoglycerin oleate, etc.
Be done. Also, as polyglycerin fatty acid ester, charcoal
Polyester of saturated or unsaturated fatty acid having 12 to 18 elementary atoms
Compounds selected from the group consisting of lyserine esters are preferred.
Good Specifically, polyglycerin laurate, polyglycerin
Serine palmitate, polyglycerin stearate, po
Liglycerin oleate and the like can be mentioned and used appropriately.
The sorbitan fatty acid ester has 1 carbon atom.
Group consisting of 2 to 18 saturated or unsaturated fatty acid esters
More preferred compounds are preferred. Specifically, sorbitan
Laurate, sorbitan palmitate, sorbitan steat
Arate and sorbitan oleate are used as appropriate.
It Furthermore, as polyoxyethylene alkyl ether
Is a polyoxy alcohol of a saturated alcohol having 12 to 18 carbon atoms.
Selected from the group consisting of cyethylene alkyl ethers
Compounds are preferable, and ethylene oxide is more preferable.
Polyoxyethylene alkyl having an addition mole number of 3 to 7
Ruther is preferred. Specifically, polyoxyethylene
Lauryl ether, Polyoxyethylene palmityl A
Tell, polyoxyethylene stearyl ether, etc.
Be used appropriately.

Claims (1)

[Claims] 1. A polyvinyl chloride resin composition containing absolute humidity
A method for producing a polyvinyl chloride stretch film, which comprises extruding in an atmosphere of 0.014 to 0.024 kg / m ³ and then winding the film in a temperature range of 35 to 45 ° C.