JPS60212434A - Separation and recovery of composite material - Google Patents

Abstract

PURPOSE:A composite of a thermoplastic resin and aluminum foil is dipped in a specific solvent to dissolve off the adhesive, then rinsed with water to separate into the resin and the foil, thus enabling their recovery in pure forms free from the other components. CONSTITUTION:A composite which has been made by adhering aluminum foil to thermoplastic resin with an adhesive is dipped in a solvent which can penetrate the resin and dissolves the adhesive to dissolve off the adhesive or lower its adhesion. Then, the composite is taken out of the solvent, then rinsed with water to peel off the aluminum foil from the resin. The solvent used contains 15vol% of a solvent selected from alkyl esters of lower fatty acids, lower aliphatic ketones, 6-10C hydrocarbon, 1-8C halogenated hydrocarbons and ethers.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for separating a thermoplastic resin and aluminum foil from a composite of thermoplastic resin and aluminum foil and recovering them separately.

Composites made by bonding thermoplastic synthetic resin and aluminum foil with adhesive are frequently used as packaging materials for pharmaceutical products, food products, etc., and manufacturing plants for pharmaceutical products, food products, etc. have a large amount of sludge from the composite materials. as a by-product. Conventionally, methods for recovering these composite wastes include: (1) crushing, heating above the thermal deformation temperature of the resin to shrink it, and peeling and separating the resin and aluminum foil (Japanese Unexamined Patent Publication No. 48-68678); (1) separating the resin from the aluminum foil; After pulverizing the aluminum composite waste, it is stirred in an organic solvent whose specific gravity is lower than that of aluminum and higher than that of resin, and the resin-containing layer and the aluminum-containing layer are separated and the solvent is removed from each of these layers. A method of separately recovering resin and aluminum by
4-127988) is known. However, in the above method (■), the resin and aluminum foil are not completely separated, and
Even in the above method, a small amount of aluminum is mixed into the resin layer, or a small amount of resin is mixed into the aluminum layer, and it is not possible to completely separate the two in either method.

As described above, none of the conventionally known methods is fully satisfactory.

In view of these circumstances, the present inventors conducted various studies, and as a result found a method for easily separating thermoplastic resin and aluminum and recovering each, and completed the present invention.

That is, in the present invention, a composite formed by bonding a thermoplastic resin and aluminum foil with an adhesive is immersed in a solvent that can penetrate the thermoplastic resin and understand the adhesive to dissolve the adhesive. or reduce the adhesive force thereof, the composite and the solvent layer are separated, the composite is washed with water, and then the resin of the composite and the aluminum foil are separated. This method collects aluminum foil and aluminum foil individually.

Examples of the thermoplastic resin include polyolefin resins (polyethylene, polypropylene).

Examples include polyvinyl chloride, polyvinylidene chloride, and polyester (polyester terreclate, etc.).

The solvent used in the present invention may be any solvent as long as it can penetrate the thermoplastic resin and dissolve the adhesive. Specific examples thereof include methyl acetate,
Ethyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, ethyl butyrate, etc. with 8 or more carbon atoms
6 lower alkyl esters of lower fatty acids, such as acetone.

Methyl ethyl ketone, methyl isobutyl ketone.

Lower aliphatic ketones with 8 to 7 carbon atoms such as diethyl ketone, cyclohexanone, methylcyclohexanone, etc., such as hexane, octane, nonane, decane, benzene, toluene, xylene, etc. ``Hydrocarbons having 6 to 10 carbon atoms,
For example, halogenated hydrocarbons having 1 to 8 carbon atoms, such as carbon tetrachloride, dichloroethane, trichloroethane, dichloroethylene, trichlorethylene, and tetrachlorethylene;
Examples include ethers such as dimethyl ether, diethyl ether, methyl ethyl ether, and tetrahydrofuran, and mixtures of two or more of these.

These solvents may be a mixture with other solvents, and this lifting table contains at least 15% by volume of the solvent defined in the present invention.
Preferably, one containing 20% by volume is used.

Specific examples of the mixed solvent that can be used in the present invention include gasoline, solvent naphtha, and the like.

Normally, hot melt adhesives such as ethylene acetate pico-polymer and ethylene polymer are used to bond thermoplastic resin and aluminum foil, and the present invention can be applied to composites bonded with such adhesives. Applicable.

The composite used in the method of the invention is strip-shaped.

It can be of any shape, such as a sheet, but the length is 1
It is preferable to use a band-like material having a length of m or more. Further, it is preferable that the band-shaped composite is wound into a roll.

In carrying out the present invention, the composite is first immersed in a solvent. As a specific means, the tank may be filled with a solvent and the complex may be introduced into the tank, or the complex may be first stored in the tank and then the solvent may be filled in the tank. As a result, the solvent penetrates into the resin from the resin surface of the composite,
It passes through the resin and reaches the adhesive layer. This dipping is continued until the adhesive dissolves or the adhesive strength of the adhesive becomes weaker than both the tensile strength of the resin and the aluminum foil. The immersion time varies depending on the type and thickness of the resin, the type of solvent, and the temperature, but is usually about 2 minutes to 8 hours. If the flash point of the solvent used is relatively high, heating may be used, and heating can accelerate the dissolution of the adhesive or the rate at which its adhesive strength decreases. Heating is carried out at a temperature below the flash point of the solvent. When the resin is polyvinyl chloride or polyvinylidene chloride, the solvent may be lower alkyl esters of lower fatty acids, lower aliphatic ketones, or carbon atoms having 1
at least 16% by volume of one or more solvents selected from the group consisting of ~8 halogenated hydrocarbons and ethers;
It is better to use a solvent that contains In this case, if the thickness of the resin is 0.16 to 0.85 mm and the temperature of the solvent is around room temperature, the appropriate immersion time is about 2 minutes to 8 hours. When the resin is a polyolefin, lower alkyl esters of lower fatty acids, lower aliphatic ketones, and carbon atoms of 1 are used as solvents.
It is preferable to use a solvent containing at least 15% by volume of one or more solvents selected from the group consisting of halogenated hydrocarbons having a carbon number of ~8 and hydrocarbons having a carbon number of 6 to 8; in this case, the thickness of the resin is 0.15 to 0.25, and if the temperature of the solvent is around room temperature, the appropriate immersion time is about 80 minutes to 8 hours. When the resin is polyester, a lower alkyl ester of a lower fatty acid and a carbon number of 6 to 8 are used as a solvent.
It is preferable to use a solvent containing at least 15% by volume of one or more solvents selected from the group consisting of hydrocarbons,
In this case, if the thickness of the resin is between 0.15 and 0.8 and the temperature of the solvent is around room temperature, the appropriate immersion time is about 1 to 6 hours. If the immersion time is too short, the adhesive force of the adhesive will not decrease, and if the immersion time is too long, the resin will swell and the tensile strength of the resin will become weaker, which is not preferable.

In the method of the invention, the complex and solvent layers are then separated. As a specific means for this, the solvent in the tank may be turned off, or the complex may be taken out from the tank.

The composite separated from the solvent layer is then washed with water.

As a specific means for this, the solvent may be washed away by pouring water onto the complex, or the complex may be placed in a tank and filled with water to replace the solvent adhering to the complex with water. may be removed from the tank.

It is preferable to wash the composite with water immediately after separating it from the solvent layer. If the composite is left for a long time after being separated from the solvent layer, the solvent adhering to the composite will penetrate into the resin and further swell the resin, further weakening the tensile strength of the resin.
Further, the solvent evaporates in the air, which is not preferable.

The washed composite is then separated into resin and aluminum foil. A specific method for this is to physically pull the resin and aluminum foil in different directions. If the adhesive has been dissolved by the solvent, it can be easily separated by this operation, and even if the adhesive is not completely dissolved, if its adhesive strength has decreased, the two can be easily separated by the above operation. When the composite is in the form of a strip or roll, the resin and aluminum foil may be separated by rolling the roll, and each may be wound into a roll separately. Further, the resin and aluminum foil may be separated or separated and then cut one after another.

In this way, the resin and aluminum foil can be recovered separately from the composite waste of thermoplastic resin and aluminum foil, and these can be reused for their respective uses.

According to the method of the present invention, both resin and aluminum can be recovered, and both the recovered aluminum and resin are completely free from contamination with the other, and both are isolated as pure substances.

EXAMPLES The present invention will be described in more detail with reference to Examples below.

Example 1 A composite (rl12101N) in which polyvinyl chloride resin (thickness: 0.151 g) and aluminum foil are adhered with a hot melt adhesive of ethylene-vinyl acetate copolymer.

4m in length) wound into a roll (roll diameter: approx. 60 mm) is placed in a cylindrical container with an inner diameter of approx.
V%, isopropanol 20V%.

Acetone 15V%, toluene 15V%) were added thereto and immersed at room temperature for 80 minutes. Then, the solvent was taken out, the container was filled with water, and the container was washed with water. After repeating water washing twice, the composite was taken out from the cylindrical container. The resin and aluminum foil were completely peeled off, and the two could be separated with almost no resistance. The ends were manually separated into resin film and aluminum foil, and each end was attached to each roll of a separating device equipped with two take-up rolls, and each end was separated at a speed of about 0.6 to x m/sec. was rolled up and separated, and the resin film and aluminum foil were collected individually.

Examples 2 to 21 The composite used in Example 1 was treated in the same manner as in Example 1 under the following conditions, and the resin film and aluminum foil were individually collected.

Note) 1) After the immersion, the resin and aluminum foil are completely peeled off, and the two can be separated with almost no resistance.

2) The resin film turned white after washing with water.

8) After immersion, the resin and aluminum foil do not separate, but the adhesive strength is weak, and they can be easily separated by applying physical force and pulling the resin and aluminum foil apart in different directions.

Example 22 Composite made of polypropylene (thickness 0.211 av) and aluminum foil adhered with polyethylene hot melt adhesive (width 210 mm, length approximately 450 m rolled into a roll (roll diameter: approximately 380 ffll) ) with an inner diameter of approximately 400
The mixture was placed in a cylindrical container with a lid of about 250 mN and height, and trichlorethylene was added thereto and immersed at room temperature for 1 hour.

Then, the solvent was removed and the sample was washed with water in the same manner as in Example 1. (The resin film and aluminum foil have completely peeled off,
Both peel off with almost no resistance. ) Thereafter, the resin film and aluminum foil were individually collected by processing in the same manner as in Example 1.

Examples 28 to 36 The following was carried out in the same manner as in Example 1 using the composite used in Example 22 (length: 4 m) wound into a roll (roll diameter: approximately 601'l). The resin and aluminum foil were collected separately.

Notes and notes 1), 2), and 8) have the same meanings as in the tables of Examples 2 to 21.

Examples 87-50 The following five types of composites were treated in the same manner as in Example 1 under the following conditions, and the resin film and aluminum foil were individually collected.

Composite ■ Polyethylene resin film (thickness 0.2511ff
) and aluminum foil adhered using a polyethylene-vinyl acetate copolymer hot melt adhesive (width 210g)
m, length approximately 4 m) wound into a roll (roll diameter: approximately 60 m) ■ Polyvinylidene chloride resin film (thickness 0゜2 m)
m) and aluminum foil adhered using ethylene-vinyl acetate copolymer hot melt adhesive (+1J2t
4 m long) wound into a roll (diameter of roll: approximately 60 im) ■ Polyester resin film (thickness: 0.8 mm) and aluminum; 6 are bonded using polyethylene hot melt adhesive. Soaked complex (rl,] 210
ytyt, length approx. 4m) rolled into a roll (roll diameter: approx. 60mm) ■ Polyvinyl chloride (150μ), polyvinylidene A (18μ), polyethylene (15μ), polyvinylidene chloride (18μ) , polyvinyl chloride (150/()
A composite (RL) 2to fin, approximately 4m in length, is made by laminating a resin film and aluminum foil in this order and bonding them with an ethylene-vinyl acetate copolymer hot melt adhesive.
) rolled into a roll (roll diameter: approx. 6 on+
) Notes and Notes 4iYtl 1), 2), and 8) have the same meanings as in the tables of Examples 2 to 21.

Procedure Amendment (voluntary) May 70, 1980 2 Name of the invention Composite material separation and recovery method 3 Relationship to the case of the person making the amendment Patent applicant address 2-27 Doshomachi, Higashi-ku, Osaka Name (29
3) Takeda Pharmaceutical Co., Ltd. Representative: Iku Kurabayashi Department 4, Agent address: Takeda Pharmaceutical Co., Ltd. Osaka Factory, 2-17-85 Jusanhonmachi, Yodogawa-ku, Osaka City 6, Invention of the specification subject to amendment Detailed explanation column 7, contents of amendment (1) "Understanding" in page 4, line 14 of the specification is corrected to "dissolution, J.

(2) “Polyvinylidene chloride” on page 5, line 3 of the same book is “
Corrected to "Polyvinylidene Chloride."

(3) "Polyester terephthalate" on page 5, line 4 of the same book has been corrected to "polyethylene terephthalate."

(4) “Published by Ethylene Thread Polymer” on page 6, line 12 of the same book.
Corrected to "polyethylene-based".

(5) Insert rffJ after ro, 15 to 0.25J on page 8, line 10 of the same book.

(6) In the table on page 12 of the circular, the solvent used in Example 6 is corrected as follows.

[Lacquer thinner (toluene 42V%, xylene 14%)
V%, ethyl acetate 15V%, butyl acetate 1v%, isobutyl acetate) vi V N + methanol 4v% methyl isobutylene ~ ketone 2v%, ethano/L/3v%, isoglobanol/L'4V96+n-butano/1/3v96
．． Isobutanol 2v%, acetone 5V%.

Methyl ethyl ketone 4v%” that's all

Claims (1)

[Claims] 1. A composite formed by bonding thermal T'iJ plasticity 41'j1 resin and aluminum foil with an adhesive is immersed in a solvent that can permeate the thermoplastic resin and dissolve the adhesive. After dissolving the adhesive or reducing its adhesive strength, the composite and the solvent layer are separated, the composite is washed with water, and then the composite resin and aluminum foil are separated. An additive that collects thermoplastic resin and aluminum foil individually by separating them. 2. The solvent is (V lower alkyl esters of lower fatty acids,
■Lower aliphatic ketones, (3) hydrocarbons with a6 to 10 carbon atoms, ■halogenated hydrocarbons with 1 to 8 carbon atoms, and (
(2) The method according to claim 1, wherein the solvent contains at least 15% by volume of one or more solvents selected from the group consisting of ethers. 8. The method according to claim 1, wherein the adhesive is an ethylene-vinyl acetate copolymer-based or polyethylene-based hot melt adhesive. 4. The thermoplastic resin is polyvinyl chloride or polyvinylidene chloride, and the solvent is lower alkyl esters of lower fatty acids or lower aliphatic ketones. At least 15 solvents selected from the group consisting of halogenated hydrocarbons having 1 to 8 carbon atoms and ethers.
% by volume of the solvent. 5. The thermoplastic resin is a polyolefin, and the solvent is lower alkyl esters of lower fatty acids, lower aliphatic ketones, halogenated hydrocarbons having 1 to 8 carbon atoms, and 6 carbon atoms.
The method according to claim 1, wherein the solvent contains at least 15% by volume of one or more solvents selected from the group consisting of -10 hydrocarbons. 6. The thermoplastic resin is polyester, and the solvent contains at least 15% by volume of one or more solvents selected from the group consisting of lower alkyl esters of lower fatty acids and halogenated hydrocarbons having 2 to 6 carbon atoms. The method according to claim 4.