JPS60105518A - Manufacture of two layer film with anticorrosion property - Google Patents

Abstract

PURPOSE:To produce a two layer film with anticorrosion property by compounding volatile anticorrosive agent into the resin of an inner layer in the process of two layer inflation molding. CONSTITUTION:Two layer film is made by compounding 1.5-10wt% volatile anticorrosive agent with heat resisting property (e.g. dicyclohexyl ammonium salt laurate) into the resin of an inner layer. This two layer film is molded by inflation extruding method. The anticorrosive agent is evaporated in the inner space 5 of the two layer film 1 extruded into a tubular shape 4, and sublimated and stuck onto the surface of the inner layer, whereby the two layer film with excellent anticorrosion may be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention uses a plastic resin composition containing a specific anti-corrosion agent as a resin for the inner layer of a two-layer film using an inflation two-layer extrusion method. A plastics resin composition containing no rusting agent is used as the resin for the outer layer of the two-layer film, and a vaporizable resin is added to the inner space of the tubular body of the two-layer film immediately after being extruded into a tubular shape at a specific extrusion temperature. The present invention relates to a method for manufacturing a two-layer film having excellent anti-corrosion performance by cooling and solidifying a tubular two-layer film while evaporating and sublimating a rust preventive agent to fill the film.

The two-layer film obtained by the production method of the present invention can be used as a packaging material for various articles requiring rust prevention.

Conventionally, as a method for producing a two-layer film containing an anticorrosive agent by the inflation two-layer extrusion method, for example, the production of a rust-preventive film described in Takkai Sho 48-1% No. 971 has been used. The law was known.

However, in the known manufacturing method, the amount of rust preventive agent remaining in the resin layer of the resulting rust preventive film is often extremely small, and such films do not last long after they are used. It did not stably exhibit a sufficient rust-preventing effect over a long period of time, and could not be used practically as a packaging material with high rust-preventing performance.

As a result of intensive research into a method for manufacturing a two-layer film with excellent rust prevention performance, the inventors solved the drawbacks of known methods for manufacturing rust prevention films. By using a plastics resin composition containing a high blending ratio of anticorrosion inhibitors for the inner layer and extruding a two-layer film tubular body using the inflation two-layer extrusion method under specific molding conditions, we have created an excellent The inventors discovered that it was possible to produce a two-layer film with anti-rust properties and completed this invention.

This invention provides a method for forming a two-layer film using a plastics resin by an inflation two-layer extrusion method, in which a heat-resistant vaporizable rust preventive agent having a decomposition temperature of about 150°C or higher is used for plastics. The first resin composition, which is blended with the plastic resin at a ratio of about 1.5 to 10% by weight, is used as the resin composition for forming the inner layer of the two-layer film, and the rust preventive is added to the plastic. A second resin composition that is not blended with the base resin is used as the resin composition forming the outer layer of the two-layer film, and the extrusion temperature is 140°C or higher and lower than the decomposition temperature of the volatile rust inhibitor. , vaporizable rust preventive agent is evaporated and/or sublimated from the inner layer resin layer of the tubular body of the two-layer film immediately after being extruded into the tubular body into the interior space of the tubular body, and the interior space is protected against rust. A two-layer film with anti-corrosion performance characterized by cooling and solidifying a tubular two-layer film while filling it with a rust-preventing agent to form a two-layer film containing and adhering to the inner surface of the anti-corrosion agent. Regarding manufacturing methods.

This invention uses a plastics resin composition containing a high proportion of a specific heat-resistant vaporizable rust preventive agent for the inner layer of the two-layer film. This prevents the corrosion inhibitor from being decomposed and lost at the molding temperature, and does not cause significant air bubbles to form within the film that is being formed. After the rust preventive agent fills the internal space of the tubular body of the two-layer film in a molten and softened state, the inner space of the tubular body of the two-layer film is filled again.
Since the anti-corrosion agent is incorporated into the surface of the W, the anti-corrosion agent on the surface acts on the packaged object from the moment the two-layer film is used for packaging, and exhibits sufficient anti-rust effects. .

In particular, the two-layer film obtained by the production method of the present invention has a sufficient amount of the volatile rust inhibitor in the inner layer, and a high proportion of the volatile rust inhibitor on the surface of the inner layer. When the two-layer film is used as a packaging material, the vaporizable rust preventive agent on the surface of the inner layer of the two-layer film starts to exert its rust-preventing effect immediately after the two-layer film is used. Moreover, since the volatile rust inhibitor inside the inner layer of the two-layer film gradually moves to the surface and subsequently evaporates, it can exhibit a corrosion-preventing effect over a long period of time.

In addition, although the manufacturing method of this invention uses a plastics resin composition containing a considerably large amount of a volatile rust preventive agent and performs inflation two-layer extrusion molding at a considerably high temperature, Since the high-temperature two-layer film tubular body has its outer layer made of a plastic resin composition that does not contain a volatile rust preventive agent, the volatile rust preventive material is removed from the outer peripheral surface of the tubular body. This prevents the rust agent from evaporating and sublimating, thereby deteriorating the working environment at the extrusion molding site.

The manufacturing method of this invention will be explained below with reference to the drawings.
I will explain in more detail.

FIG. 1 is a cross-sectional view schematically showing an example of the manufacturing method of the present invention.

FIG. 2 is a sectional view showing a part of an example of a two-layer film obtained by the manufacturing method of the present invention.

In this invention, the resin composition used in the inflation two-layer extrusion method is such that the first resin composition forming the inner layer of the two-layer film has a decomposition temperature (approximately 0° C./min. (shown as the temperature at which 50% by weight or more of the sample is thermally decomposed) is approximately 150°C or higher, particularly 155 to 250°C, more preferably 160 to 230°C.
A volatile rust inhibitor having a heat resistance of 1.5 to 10% by weight, particularly 2 to 8% by weight, is added to the plastic resin.
More preferably, the resin composition may be blended at a ratio of 3 to 7% by weight, and the second resin composition forming the outer layer of the two-layer film may contain the above-mentioned volatile rust preventive for plastics. This is a resin composition that is not blended with a resin.

The blending ratio of the volatile rust preventive agent in the first resin composition is 1
．． If it is less than 5% by weight, when such a resin composition is used for an inner layer, the volatile rust preventive agent in the inner resin layer will evaporate and sublimate during molding, resulting in a small amount (too much) inside the resin composition.
This is not appropriate because the long-term rust-preventing effect will decrease, and even if the proportion of the volatile rust-preventive agent is too high, the rate at which the rust-preventing effect increases due to the excess rust-preventive agent will decrease.
This is not appropriate because the effect of excessive bone blending is lost and the physical properties of a film formed from a resin composition containing such a high rust inhibitor content are deteriorated.

Examples of the above-mentioned volatile rust preventives include organic ammonium salts of higher fatty acids (dicyclohexylammonium laurate, dicyclohexylammonium caprylate, dicyclohexylammonium myristate, dicyclohexylammonium palmitate, dicyclohexylammonium stearate, and succinate). Inorganic acid salts of organic amines (nitrites of alkyl amines such as ethylamine nitrite, methylamine nitrite, morpholine nitrite, naphthylamine nitrite, benzylamine nitrite, phenylamine nitrous acid) nitrites of aromatic monoamines such as salts, and nitrites of organic ammoniums such as dicycloammonium nitrite, diisopropylammonium, nitrite, dicyclohexylammonium nitrite, morpholin ammonium nitrite, etc. Organic amine salts of aromatic acids such as Yj'' organic ammonium salts (dicycloammonium benzoate, isopropylammonium benzoate, 2-butylammonium benzoate, etc.), morpholine benzoate, etc. acids, fatty acids such as capric acid and becargonic acid, aromatic acids such as benzoic acid and naphtholic acid), heterocyclic amines (benzotriazole, methylbenzotriazole, 3-amino-1,2,4-benzotriazole, etc.), Examples include nido-0-substituted aromatic compounds (rn-dinitrobenzene, di-I:J naphthalene, etc.).

In particular, in this invention, the volatile rust preventive agent is a volatile rust preventive agent whose main component is an organic amine salt or ammonium salt of an aromatic acid whose decomposition temperature is 155 to 250°C. It is optimal in terms of heat resistance and rust prevention, ease of mixing and kneading with plastic resins at high temperatures, and physical properties of the resulting two-layer film.

In this invention, the plastic resin used in the resin composition includes, for example, low-density polyethylene (
LDPE, LLDPE, etc.), high density polyethylene (H
DPR), polypropylene, ethylene-6′r acid bivinyl copolymer, ethylene-propylene copolymer, ethylene-(meth)acrylonitrile copolymer, polyvinyl chloride, polyester, polyamide, and other thermoplastic resin compositions. I can do it.

The resin composition may appropriately contain additives such as plasticizers, anti-aging agents, antioxidants, colorants, and reinforcing agents.

The resin composition used in this invention has a melt flow index (Ml) of 0.1 to 30 g/10 min, particularly 0.5
~15 cm/10 minutes, and those containing an ethylene polymer as the main component are preferable.

The resin composition used in this invention can be obtained by blending and kneading the above-mentioned components by a known method. Then, melt and knead plastics resin, volatile rust preventive agent, etc. to make about 15 to 60% by weight of volatile rust preventive agent.
In particular, a plasti-sol resin composition (master hatch pellet) containing a proportion of about 20 to 50% by weight is prepared, and then, during actual inflation two-layer extrusion molding, the master hatch pellet is It is preferable to prepare the resin composition by blending it with a plastics resin and supplying it to a two-layer extrusion molding machine to form the first resin composition for the inner layer inside the extrusion molding machine.

In the manufacturing method of the present invention, since the second resin composition forming the outer layer of the tubular two-layer film does not contain evaporation barrier 6B+1, when the tubular body of the two-layer film is extruded by inflation molding, The volatile rust preventive agent in the inner layer of the tubular body evaporates and sublimates toward the outside of the tubular body under high temperatures during molding, deteriorating the working environment around the molding area. This can be prevented by the outer layer containing no agent.

The manufacturing method of the present invention uses the above-described first and second resin compositions to form a two-layer film tubular body by an inflation two-layer extrusion method, and the extrusion temperature is set to about 140°C. The temperature is preferably 145° C. or above and below the above-mentioned decomposition temperature of the volatile rust inhibitor, and the resin layer is the inner layer of the tubular body of the two-layer film immediately after being extruded into the tubular shape. evaporate and/or sublimate the volatile rust preventive agent into the interior space of the tubular body to fill the interior space, if necessary, approximately 1.2
The tubular two-layer film is cooled and solidified at a blowing ratio of ~6 times, especially about 1.5 to 5 times, to form a two-layer film that contains a rust preventive agent and is coated on the inner surface (4 times). It is.

In the above-mentioned inflation two-layer extrusion molding, in order to fill the internal space of the tubular body of the two-layer film with a vaporizable rust preventive agent, a specific heat-resistant vaporizable rust preventive compounded in the first resin composition must be used. It is particularly important to select a rust agent, to mix the rust inhibitor at the high mixing ratio mentioned above, and to keep the extrusion temperature for molding within the range of the limiting conditions mentioned above. When the inner space of the tubular body of the two-layer film is filled in the former stage, the inner space of the tubular body is supersaturated with the volatile rust preventive agent, and is filled to the extent that it becomes cloudy in the form of mist. This is desirable in the present invention because the volatile rust inhibitor is then adhered to or incorporated into the inner surface of the inner layer of the two-layer film tubular body in a reasonably uniform manner.

A specific embodiment of this invention will be described with reference to FIG.

In this invention, first, for example, low density polyethylene (density: 0.915 to 0.935 g/c++1.M I
: 1.0 to ljg/10 minutes) as a plastics resin, and an organic ammonium salt or an organic amine salt of an aromatic acid as a volatile rust preventive compounded in the first resin composition. Approximately 130 to 160 on a twin-screw extruder
The above volatile rust inhibitor is melted and kneaded at a temperature of about 2°C.
Masterbatch pellets containing 0 to 50% by weight were prepared.

Next, as shown in FIG. 1, a first extrusion device (not shown) is connected in front of the first resin composition supply channel 7 of the two-layer extrusion die 6 used for the inflation two-layer extrusion method. The above-mentioned master patch pellets and the same low-density polyethylene as above were supplied to 140-1
A first resin composition is prepared by melting and kneading at a temperature of 80°C, and while supplying the first resin composition to the supply path 7 of the die 6, another second resin composition is prepared. Low-density polyethylene similar to the one described above is supplied to a second extrusion device (not shown) connected before the resin composition supply path 8, and a second resin in a molten and softened state is produced. The composition was supplied to the supply channel 8 of the die 6 described above.

and a further annular extruded resin channel 9 connected to the supply channel 7 and forming the inner layer of the tubular body of the two-layer film;
The first and second resin compositions are forced into the annular extruded resin passage 10 connected to the supply passage 8 and used to form the outer layer of the two-layer film tubular body under extrusion pressure. Then, from the annular I+1:out 1'' 12 of the inflation two-layer extrusion molding die 6, the tubular body of the two-layer film is heated to a temperature of about 140'C or higher and at a temperature above about 140'C, the decomposition temperature of the vaporizable rust inhibitor. (approximately 150 to 230°C) or less to form a two-layer film tubular body, and the vaporized rust preventive agent is evaporated from the inner layer of the tubular body 4 into the internal space 5 of the tubular body 4.・Sublimate and its internal space 5
The inside of the tubular body 4 is fogged into a mist, and in that state, the tubular body 4 is cooled and solidified by water cooling, air cooling, etc. to form a two-layer film, and finally, the tubular body 4 is passed through guide rolls 13 and 14. It is folded in half and wound up as a roll-shaped two-layer film 15.

In addition, in the above manufacturing method, the two-layer film tubular body 4 extruded from the extrusion die 6 is controlled by the blowing ratio at an appropriate magnification due to the pressure G of the air from the air supply path 11 provided in the die 6. You can change it easily.

As shown in FIG. 2, the two-layer film obtained by the production method of the present invention contains an outer layer 2 of Plasti-Nox resin that does not contain a volatile rust inhibitor and a volatile rust inhibitor. It is a two-layer film consisting of an inner layer 3 of Plasti-Nox resin.

In the above two-layer film, the outer layer 2 has a thickness of about 10 to 200μ,
In particular, the thickness is between 20 and 150μ, and the inner layer 3 is approximately 3μ thick.
The thickness is preferably 0 to 300μ, particularly 40 to 250μ, and the total thickness is preferably about 50 to 400μ, especially about 75 to 250μ.

The above-mentioned two-layer film has an inner layer that contains a sufficient amount of a vaporizable rust preventive agent, and also has a vaporizable rust preventive agent attached to its surface, making it easy to package. Immediately after being used as a rust-preventing film for
It also shows long-term rust prevention effects as a rust prevention film for packaging.

Examples 1 to 3 Low density Ho'J :f-chil/ :/ (VB degree: 0.
915 g/cJ, MI: 5 g/10 min) and 20 parts by weight of dicyclohexylammonium benzoate powder were supplied to a twin-screw extruder extruder and kneaded at 150°C to form a pellet. A masterbatch was molded.

Using an inflation double-layer extrusion molding machine as shown in Figure 1, the master patch and low-density polyethylene are appropriately mixed in the first extrusion device, and a volatile rust preventive agent is mixed in the proportions shown in Table 1. The first resin & II composition prepared at 155° C. was supplied to the supply path 7, and at the same time, low-density polyethylene alone was supplied to the second extrusion device to form a second resin composition. The two-layer film tubular body 4 is extruded from the discharge port 12 of the die 6 at an extrusion temperature of 50°C, and the two-layer film is stretched by two wheels approximately three times. A volatile rust preventive agent is evaporated and sublimed from the inner layer of the film tubular body to fill the interior space 5 of the tubular body to the extent that it becomes cloudy, and then the tubular body is cooled and solidified by air cooling. Inside N
A two-layer film is formed in which the layer 2 (layer containing the volatile rust preventive) has a thickness of 50 μm and the outer layer 3 has a thickness of 50 μm, and the formed tubular body is folded in half and further rolled into a roll. I took it.

After polishing the cold-rolled steel with sandpaper, degreasing it with an organic solvent, and drying it, it is placed in a bag made from the two-layer film formed as described above and sealed with a heat seal, at a humidity of 95%. As described above, a rust prevention test was conducted by hanging the steel plate in a constant temperature and humidity chamber at a temperature of 50°C, leaving it for two months, and observing the state of corrosion (rust) on the surface of the steel plate. The results of the rust prevention test are shown in Table 1.

Comparative Example 1 A two-layer film was molded in the same manner as in Example 1, except that the blending ratio of the volatile rust inhibitor in the first resin composition was changed as shown in Table 1.

A rust prevention test similar to that in Example 1 was conducted using a bag made from the two-layer film thus obtained. The results are shown in Table 1.

Table 1 First resin composition Rust prevention test results of volatile rust inhibitors Blending ratio weight% Example 1 3.0 No support for 2 months Vibration does not occur Example 2 4.0 No support for 2 months Vibration does not occur Example 3 5.0 No support for 2 months Vibration does not occur Comparative Example 1 1.0 Black rust in about 1 week There has occurred

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view schematically showing an example of the manufacturing method of the present invention. FIG. 2 is a sectional view showing a part of an example of a two-layer film obtained by the manufacturing method of the present invention. l: two-layer film, 2: outer layer, 3: inner layer, 4: tubular body of two-layer film, 5: internal space, 6: two-layer extrusion die, 7
: first resin composition supply path, 8: second resin composition supply path, 11: air supply path, 12: die outlet. Patent applicant: Ube Industries, Ltd.

Claims (1)

[Claims] A method for forming a two-layer film using a plastic resin by an inflation two-layer extrusion method, comprising: a heat-resistant vaporizable rust preventive having a decomposition temperature of about 1'50°C or higher; A first resin composition in which the agent is blended with the plastic resin at a ratio of about 1.5 to 10% is used as the resin composition forming the inner layer of the two-layer film, and the A second resin composition in which a rust agent is not blended with the plastic resin is used as the resin composition for forming the outer layer of the 21H film, and the decomposition temperature of the volatile rust preventive is 140°C or higher. At an extrusion temperature below, a volatile rust inhibitor is evaporated and/or sublimated from the resin layer of the inner layer of the tubular body of the two-layer film immediately after being extruded into the tubular body into the internal space of the tubular body. ,
A two-layer film with anti-rust performance characterized by cooling and solidifying a tubular two-layer film while filling its internal space to form a two-layer film containing a rust preventive agent and attached to the inner surface. Film manufacturing method.