JP7676816B2 - Silicone release layer remover, silicone release layer removal method, recycled polyester manufacturing method, and recycled polyester product - Google Patents

Description

The present invention relates to a silicone release layer remover, a silicone release layer removal method, a method for producing recycled polyester, and a recycled polyester product.

Traditionally, waste plastic has been disposed of by landfilling, dumping at sea, incineration, etc., but it is becoming difficult to secure landfill sites, and dumping at sea is posing environmental problems because plastic does not decompose.
In addition, while it is possible to use the waste as heat by incineration, this has the problem of emitting carbon dioxide, which contributes to global warming.

In light of the recent heightened environmental concerns, there is a need to reuse, regenerate, and recycle waste plastics, and research and development into this area is being actively carried out. Furthermore, since most plastics are produced using fossil fuels, there is a need to develop recycling methods to make effective use of resources.

By the way, polyester film, which is a type of plastic film, is useful as a base film, and is often used as a laminate film with various functional layers laminated on one or both sides. There are various functional layers, such as a release layer, a hard coat layer, an adhesive layer, a decorative layer, a light-shielding layer, a polarizing layer, and an ultraviolet-shielding layer, and laminate films are used in which materials appropriate for the functional layer are laminated on a polyester film.

Such laminated films are rarely reused after use, but are instead discarded or incinerated.

Even if an attempt is made to recycle a laminated film with a functional layer laminated thereon by simply remelting it, the material that constitutes the functional layer will be mixed into the molten polymer, causing an unpleasant odor during extrusion or a decrease in the melt viscosity of the polymer, which can lead to breakage during film production.
Even if it were possible to produce a film, degradation of quality due to discoloration of the resulting film or contamination with foreign matter would be unavoidable.

Even if the functional layer is physically removed by scraping it off and then melt extrusion is performed, the remaining functional layer can cause the filter to become clogged during the filtration process during extrusion, resulting in problems such as failure to produce a normal film.

One example of a method for recycling release films is the technology disclosed in Patent Document 1. This technology involves a release film in which a readily soluble resin layer and a release layer are laminated in that order on at least one side of a base film. With this configuration, after use, the release film is washed with a solvent that dissolves only the readily soluble resin layer but does not dissolve the base film, thereby separating and removing the release layer on the film surface from the release film and recovering only the base film. The recovered base film is remelted, making it possible to regenerate the resin composition that constituted the base film.

Patent Document 2 also discloses a method for removing a functional layer present on at least one surface of a substrate film, the method comprising the step of contacting the substrate film, which has been wound into a roll, with an alkaline treatment liquid while in a long state.

JP 2002-265665 A JP 2020-090094 A

The method disclosed in Patent Document 1, as described above, is based on the premise of a release film comprising a readily soluble resin layer and a release layer laminated in that order on the surface of a base film, and aims to remove the release layer by dissolving the readily soluble resin layer.
That is, this technique cannot be used for most release films that do not have an easily soluble resin layer, and is therefore not versatile.

In addition, the method disclosed in Patent Document 2 removes the functional layer by contacting it with an alkaline treatment liquid, but no consideration is given to the removal ability of removers for each type of functional layer.

In view of the above circumstances, the objective of the present invention is to propose a silicone release layer remover that has excellent peelability from the silicone release layer and enables the recovery of the base film, even in the case of a laminated polyester film having a silicone release layer that does not have a readily soluble resin layer.

As a result of extensive research, the inventors have focused on the Hansen solubility parameter and discovered that the problem of the present invention can be solved by satisfying a specific relationship between the polarity term of the silicone release layer surface and the polarity term of component (a) in the silicone release layer remover.
The present invention has been completed based on such findings. That is, the present invention has the following aspects.
[1] A remover for removing a silicone release layer from a laminated polyester film having a silicone release layer on the surface of the polyester film, the silicone release layer remover containing a component (a) that satisfies the relationship of the following formula (1).
|δp ₁ −δp ₂ |<8.0MPa ^0.5 ...(1)
(wherein δp ₁ represents the polar term δp of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δp ₂ represents the polar term δp of component (a).)
[2] The silicone release layer remover according to the above [1], wherein the component (a) further satisfies the relationship of the following formula (2):
|δh ₁ −δh ₂ |<11.0MPa ^0.5 ...(2)
(wherein δh ₁ represents the hydrogen bond term δh of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δh ₂ represents the hydrogen bond term δh of component (a).)
[3] The silicone release layer remover according to the above [1] or [2], wherein the component (a) further satisfies the relationship of the following formula (3):
Ra={4×(δd ₁ - δd ₂ ) ² + (δp ₁ - δp ₂ ) ² + (δh ₁ - δh ₂ ) ² } ^0.5 ≦9.2...(3)
(wherein Ra represents the HSP distance, δd ₁ , δp ₁ and δh ₁ represent the δd, δp and δh of the silicone release layer surface, respectively, in the Hansen solubility parameters [δd, δp, δh], and δd ₂ , δp ₂ and δh ₂ represent the δd, δp and δh of component (a), respectively.)
[4] The silicone release layer remover according to any one of the above [1] to [3], wherein the dispersion parameter δd of the component (a) is 15.0 to 22.0 ^{MPa 0.5} .
[5] The silicone release layer remover according to any one of the above [1] to [4], wherein the component (a) is at least one selected from the group consisting of aliphatic alcohols, aromatic alcohols, aromatic amines, and aromatic hydrocarbons.
[6] The silicone release layer remover according to any one of the above [1] to [5], further comprising component (b) an alkalizing agent.
[7] The silicone release layer remover according to any one of the above [1] to [6], further comprising a compatibilizer as component (c).
[8] The silicone release layer remover according to any one of the above [1] to [7], wherein the silicone release layer surface has a dispersion parameter δd of 16.0 to 23.0 ^{MPa 0.5} , a polar parameter δp of 2.0 to 9.0 ^{MPa 0.5} , and a hydrogen bond parameter δh of 5.0 to 12.0 MPa ^0.5 .
[9] The silicone release layer remover according to any one of the above [1] to [8], wherein the silicone release layer has a thickness of 0.003 to 1.0 μm.
[10] A method for removing a silicone release layer, comprising cleaning a laminated polyester film having a silicone release layer on the surface of the polyester film with a remover containing a component (a) that satisfies the relationship of the following formula (1):
|δp ₁ −δp ₂ |<8.0MPa ^0.5 ...(1)
(wherein δp ₁ represents the polar term δp of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δp ₂ represents the polar term δp of component (a).)
[11] The method for removing a silicone release layer according to the above [10], wherein the component (a) further satisfies the relationship of the following formula (2):
|δh ₁ −δh ₂ |<11.0MPa ^0.5 ...(2)
(wherein δh ₁ represents the hydrogen bond term δh of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δh ₂ represents the hydrogen bond term δh of component (a).)
[12] The method for removing a silicone release layer according to the above [10] or [11], wherein the component (a) satisfies the relationship of the following formula (3):
Ra={4×(δd ₁ - δd ₂ ) ² + (δp ₁ - δp ₂ ) ² + (δh ₁ - δh ₂ ) ² } ^0.5 ≦9.2...(3)
(wherein Ra represents the HSP distance, δd ₁ , δp ₁ and δh ₁ represent the δd, δp and δh of the silicone release layer surface, respectively, in the Hansen solubility parameters [δd, δp, δh], and δd ₂ , δp ₂ and δh ₂ represent the δd, δp and δh of component (a), respectively.)
[13] The method for removing a silicone release layer according to any one of the above [10] to [12], wherein the dispersion term δd of the component (a) is 15.0 to 22.0 ^{MPa 0.5} .
[14] The method for removing a silicone release layer according to any one of the above [10] to [13], wherein the component (a) is at least one selected from the group consisting of aliphatic alcohols, aromatic alcohols, aromatic amines, and aromatic hydrocarbons.
[15] The method for removing a silicone release layer according to any one of [10] to [14] above, wherein the remover further contains component (b) an alkalizing agent.
[16] The method for removing a silicone release layer according to any one of [10] to [15] above, wherein the remover further contains component (c) a compatibilizer.
[17] The method for removing a silicone release layer according to any one of the above [10] to [16], wherein the silicone release layer surface has a dispersion parameter δd of 16.0 to 23.0 MPa ^0.5 , a polar parameter δp of 2.0 to 9.0 MPa ^0.5 , and a hydrogen bond parameter δh of 5.0 to 12.0 MPa ^0.5 .
[18] The method for removing a silicone release layer according to any one of [10] to [17] above, wherein the silicone release layer has a thickness of 0.003 to 1.0 μm.
[19] A method for producing recycled polyester, comprising: a cleaning step of cleaning a laminated polyester film having a silicone release layer on a surface of the polyester film with a remover containing a component (a) that satisfies the relationship of the following formula (1); and a recovery step of recovering the washed polyester film.
|δp ₁ −δp ₂ |<8.0MPa ^0.5 ...(1)
(wherein δp ₁ represents the polar term δp of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δp ₂ represents the polar term δp of component (a).)
[20] The method for producing recycled polyester according to the above [19], further comprising a production step of producing a recycled polyester product using the polyester film recovered in the recovery step as a raw material.
[21] The method for producing recycled polyester according to the above [20], wherein the production process includes a pellet production process in which the washed polyester film is pelletized.
[22] The method for producing recycled polyester according to any one of [19] to [21] above, further comprising a rinsing step of washing away any removing agent adhering to the polyester film after washing in the washing step.
[23] The method for producing recycled polyester according to any one of [19] to [22] above, further comprising an unwinding step or a cutting step prior to the washing step.
[24] A method for producing recycled polyester according to any one of [19] to [23] above, which is carried out by a roll-to-roll method.
[25] A recycled polyester product, at least in part, containing as a raw material a polyester produced by the method for producing recycled polyester according to any one of [19] to [24] above.

The silicone release layer remover of the present invention makes it possible to easily remove the silicone release layer from a laminated polyester film having a silicone release layer, and efficiently recover the base film (polyester film).

[Silicone release layer remover]
The silicone release layer remover of the present invention (hereinafter sometimes simply referred to as "removal agent") is a remover containing a component (a) that satisfies the relationship of the following formula (1).
|δp ₁ −δp ₂ |<8.0MPa ^0.5 ...(1)
(wherein δp ₁ represents the polar term δp of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δp ₂ represents the polar term δp of component (a).)
By cleaning a laminated polyester film having a silicone release layer on the surface of the polyester film with the remover, the silicone release layer can be easily removed.

Here, it is important that the remover contains the above-mentioned component (a), and by including component (a), the silicone release layer on the polyester film can be effectively removed.

The mechanism by which the inclusion of component (a) enables the silicone release layer to be effectively removed is not clear, but is presumed to be as follows.
When the difference in polarity δp between component (a) and the surface of the silicone release layer is less than 8.0 ^MPa , the affinity between component (a) and the surface of the silicone release layer is high, and component (a) penetrates into and passes through the silicone release layer.
It is presumed that when component (a) reaches the interface between the polyester film substrate and the silicone release layer, it undergoes a nucleophilic attack on one of the components at the interface, or undergoes an ester exchange reaction with the ester bond portion of one of the components, thereby causing a saponification reaction and resulting in swelling peeling.
It is believed that the penetration effect due to the affinity between component (a) and the silicone release layer triggers saponification and swelling peeling, making it possible to remove the silicone release layer.

In addition, the mechanism by which the removal rate of the silicone release layer is improved by the inclusion of the alkalizing agent (b), component (described below), is not clear, but is presumed to be as follows.
Component (b) penetrates the silicone release layer as component (a) penetrates and penetrates the silicone release layer, and reaches the interface between the polyester film and the silicone release layer. Then, the hydroxyl groups ionized from component (b) nucleophilically attack some component at the interface, causing the saponification reaction to proceed. It is presumed that the inclusion of component (b) in this way allows the saponification reaction to proceed more efficiently, thereby improving the removal rate of the silicone release layer.

<Hansen solubility parameter>
Hansen solubility parameter (HSP) is an index that indicates the solubility of a substance, i.e., how much a substance dissolves in another substance. HSP is a solubility parameter introduced by Hildebrand, which is divided into three components, dispersion term δd, polar term δp, and hydrogen bond term δh, and expressed in three-dimensional space. The dispersion term δd indicates the effect due to dispersion force, the polar term δp indicates the effect due to dipole-dipole force, and the hydrogen bond term δh indicates the effect due to hydrogen bond force, and are expressed as follows: δd: Energy derived from intermolecular dispersion force δp: Energy derived from intermolecular polar force δh: Energy derived from intermolecular hydrogen bond force (Here, each unit is MPa ^0.5 ).

The definition and calculation of HSPs are described in the following references:
Charles M. Hansen, Hansen Solubility Parameters: A Users Handbook (CRC Press, 2007).

The dispersion term reflects the London dispersion force, the polar term reflects the dipole moment, and the hydrogen bond term reflects the effects of water, alcohol, etc.

In the present invention, the HSP [δd ₁ , δp ₁ , δh ₁ ] of the silicone release layer surface can be calculated by contacting a 2.0 μL droplet of various solvents with known HSP with the silicone release layer surface of the laminated polyester film, and calculating the interaction sphere and its center, the HSP, from the contact angle value after 30 seconds, with solvents with small contact angles being good solvents and solvents with large contact angles being poor solvents.
For the calculation, for example, commercially available Hansen Solubility Parameter calculation software HSPiP (Hansen Solubility Parameters in Practice) can be used, and the threshold values of good solvents and poor solvents may be determined so that the fitting value of the calculated interaction sphere is closest to 1. For accurate measurement, it is preferable that the solvents used in the measurement each have various HSPs [δD, δP, δH], and preferred types of solvents are as shown in Table 1. According to Table 1, contact angle measurements are performed five times for each solvent using 18 or more types of solvents, and the average value of three data excluding the largest and smallest values is taken as the contact angle of that solvent. In the table, "≧1" means that the measurement is performed for one or more types of solvents, and "≧2" means that the measurement is performed for two or more types of solvents.

In the present invention, the HSP of component (a) in the silicone release layer remover can be determined from Hansen Solubility Parameters: A Users Handbook by Charles M. Hansen (CRC Press, 2007) or from commercially available Hansen solubility parameter calculation software (such as the above-mentioned HSPiP). If the chemical structure of component (a) is clear, it can be calculated using the Y-MB (Yamamoto Molecular Break) function of HSPiP, and if the chemical structure is not clear, it can be determined by actual measurement using a conventionally known method.

(Component (a))
As described above, the remover according to the present invention contains component (a) that satisfies the relationship of formula (1). If the difference in polarity δp between component (a) and the surface of the silicone release layer is less than 8.0 ^{MPa 0.5} , the affinity between component (a) and the surface of the silicone release layer is high, and the solubility is improved, so that the silicone release layer can be easily removed.
From this viewpoint, |δp ₁ - δp ₂ | is more preferably less than 6.5 MPa ^0.5 , and even more preferably less than 5.0 MPa ^0.5 . The lower limit may be 0 MPa ^0.5 or more.

It is preferable that the component (a) further satisfies the relationship of the following formula (2).
|δh ₁ −δh ₂ |<11.0MPa ^0.5 ...(2)
(wherein δh ₁ represents the hydrogen bond term δh of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δh ₂ represents the hydrogen bond term δh of component (a).)
If the difference in the hydrogen bond parameter δh between component (a) and the surface of the silicone release layer is less than 11.0 ^MPa , the affinity between component (a) and the surface of the silicone release layer is increased, and the solubility is improved. As a result, the silicone release layer can be easily removed, which is preferable.
From this viewpoint, |δh ₁ - δh ₂ | is more preferably less than 9.0 MPa ^0.5 , and even more preferably less than 7.0 MPa ^0.5 . The lower limit may be 0 MPa ^0.5 or more.

The component (a) preferably satisfies the following formula (3) regarding the HSP distance (Ra): The HSP distance (Ra) represents the similarity of a vector due to HSP, and HSPs having similar HSPs are preferred because they have high solubility.
Ra={4×(δd ₁ - δd ₂ ) ² + (δp ₁ - δp ₂ ) ² + (δh ₁ - δh ₂ ) ² } ^0.5 ≦9.2...(3)
(wherein δd ₁ , δp ₁ and δh ₁ represent δd, δp and δh of the surface of the silicone release layer, respectively, in the Hansen solubility parameters [δd, δp, δh], and δd ₂ , δp ₂ and δh ₂ represent δd, δp and δh of component (a), respectively.)
Ra is preferably 9.2 or less, more preferably 8.7 or less, and even more preferably 8.2 or less.
When Ra is in this range, as described above, the solubility is increased and the silicone release layer can be easily removed.

In the HSP [δd ₂ , δp ₂ , δh ₂ ] of the component (a), the dispersion term δd ₂ is preferably 15.0 to 22.0 MPa ^0.5 , more preferably 16.0 to 21.0 MPa ^0.5 , even more preferably 17.0 to 20.0 MPa ^0.5 , and particularly preferably 18.0 to 19.5 ^{MPa 0.5} .
Furthermore, the polarity term _δp2 is preferably 0.0 to 9.0 MPa ^0.5 , more preferably 0.5 to 8.0 ^{MPa 0.5} , further preferably 1.0 to 7.0 ^{MPa 0.5} , and particularly preferably 1.0 to 6.5 MPa ^0.5 .
Furthermore, the hydrogen bond parameter _δh2 is preferably 1.0 to 16.0 ^{MPa 0.5} , more preferably 1.5 to 15.0 ^{MPa 0.5} , even more preferably 2.0 to 14.5 ^{MPa 0.5} , and particularly preferably 2.0 to 14.0 ^{MPa 0.5} .
When δd ₂ , δp ₂ and δh ₂ of component (a) in the silicone release layer remover of the present invention are within the above ranges, the solubility with the silicone release layer surface is increased, making it possible to easily remove the silicone release layer.

As the component (a), preferred are aliphatic alcohols such as ethanol, propanol, and butanol; aromatic alcohols such as benzyl alcohol; aromatic amines such as aniline and benzylamine; and aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene.
Among these, from the viewpoint of shortening the HSP distance (Ra), aromatic compounds are preferred, and among these, aromatic alcohols and aromatic amines are more preferred.
The component (a) may be used alone or in combination of two or more.

The boiling point of the component (a) is preferably equal to or higher than the temperature at which the remover is used, which will be described later. If the boiling point of the component (a) is equal to or higher than the temperature at which the remover is used, it is preferable because the component (a) is less likely to evaporate when used as a remover. For example, it is preferable that the boiling point of the component (a) is equal to or higher than the temperature at which the remover is used in the immersion method, which will be described later.

The content of component (a) in the entire remover is preferably 10 to 99% by mass, more preferably 20 to 98% by mass, and even more preferably 30 to 97% by mass. Within the above range, the affinity and solubility with the silicone release layer surface can be made good, and the quality of recycled polyester products such as recycled polyester films can be maintained.
In addition, in the case where the remover uses the component (c) in addition to the component (b) described below in addition to the component (a) in the remover, or where the remover is an aqueous remover, the content of the component (a) in the remover is preferably 10 to 90% by mass, more preferably 20 to 75% by mass, and even more preferably 30 to 65% by mass. Within the above ranges, the amounts of the alkalizing agent and the compatibilizing agent (b) can be made appropriate. In addition, in the case of an aqueous system, a certain amount or more of water can be contained.

(Component (b): Alkalizing Agent)
The silicone release layer remover according to the present invention preferably further contains component (b) an alkalizing agent. By using component (b) in combination, the removal rate of the silicone release layer is improved.
The alkalizing agent is a substance that makes the remover alkaline, and can also be called an alkaline agent. The alkalizing agent may be an inorganic alkalizing agent or an organic alkalizing agent, but is preferably an inorganic alkalizing agent because it is suitable for combination with the component (a) and the compatibilizer component (c) described below.

Examples of the inorganic alkalizing agent include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, etc.; alkaline earth metal hydroxides such as calcium hydroxide, barium hydroxide, etc.; alkali metal carbonates such as sodium carbonate, potassium carbonate, etc.; alkali metal phosphates such as trisodium phosphate, sodium pyrophosphate, sodium tripolyphosphate, sodium tetrapolyphosphate, tripotassium phosphate, potassium pyrophosphate, potassium tripolyphosphate, etc.; alkali metal silicates such as sodium orthosilicate, sodium metasilicate, potassium silicate, etc.; and ammonia.
Among these, alkali metal hydroxides are preferred, sodium hydroxide and potassium hydroxide are more preferred from the viewpoint of availability, and potassium hydroxide is particularly preferred from the viewpoint of cleaning properties.

The inorganic alkalizing agent in the remover may be used alone or in combination of two or more. When used in combination, it is preferable to use potassium hydroxide and sodium hydroxide from the standpoint of effectiveness and ease of handling.

Examples of the organic alkalizing agent include organic amine compounds such as N,N-bis(2-hydroxyethyl)-N-cyclohexylamine, diazabicycloundecene, diazabicyclononene, monomethylamine, dimethylamine, trimethylamine, monoethanolamine, diethanolamine, triethanolamine, morpholine, 2-(dimethylamino)ethanol, 2-(diethylamino)ethanol, 1-amino-2-propanol, and triisopropanolamine.
The organic alkalizing agent may contain the above-mentioned component (a), and if the HSP distance (Ra) of the compound is 13 or more, it is treated as an alkalizing agent.

Among the organic alkalizing agents in the remover, monoethanolamine, diethanolamine, and triethanolamine are preferred from the viewpoint of versatility, monoethanolamine and diethanolamine are more preferred from the viewpoint of availability, and monoethanolamine is particularly preferred from the viewpoint of cleaning properties.

The content of the alkalizing agent (b) in the entire remover is preferably 1 to 20% by mass, more preferably 2 to 15% by mass, and even more preferably 3 to 10% by mass. If it is within the above range, a sufficient effect as a remover can be obtained.

(Component (c): Compatibilizer)
The silicone release layer remover of the present invention preferably further contains a compatibilizer (c). The compatibilizer, when used in combination with the above-mentioned components (a) and (b), has the function of helping the silicone release layer to be dissolved from the laminated polyester film, and also has the function of solubilizing the above-mentioned components (a), (b), and other additives that are added arbitrarily. In particular, even when the remover contains water, the compatibility of the above-mentioned components (a) and (b) can be improved.

There are no particular limitations on the component (c), and any of anionic compatibilizers, cationic compatibilizers, nonionic compatibilizers, and amphoteric compatibilizers can be used.
In addition, since component (c) contains a compound corresponding to the above-mentioned component (b), when component (c) is used in combination with component (b) in the remover of the present invention, a component different from component (b) is used.

Examples of anionic compatibilizers include alkylsulfonic acid, alkylbenzenesulfonic acid, aromatic sulfonic acid, alkylcarboxylic acid, aromatic carboxylic acid, alkylnaphthalenesulfonic acid, α-olefinsulfonic acid, dialkylsulfosuccinic acid, α-sulfonated fatty acid, N-methyl-N-oleyl taurine, petroleum sulfonic acid, alkylsulfuric acid, sulfated oils and fats, polyoxyethylene alkyl ether sulfuric acid, polyoxyethylene styrenated phenyl ether sulfate, alkyl phosphoric acid, polyoxyethylene alkyl ether phosphoric acid, polyoxyethylene alkyl phenyl ether phosphoric acid, naphthalenesulfonic acid formaldehyde condensate, and salts thereof.

Examples of cationic compatibilizers include quaternary ammonium, tetraalkylammonium, trialkylbenzylammonium, alkylpyridinium, 2-alkyl-1-alkyl-1-hydroxyethylimidazolinium, N,N-dialkylmorpholinium, polyethylene polyamine fatty acid amide, urea condensate of polyethylene polyamine fatty acid amide, quaternary ammonium of urea condensate of polyethylene polyamine fatty acid amide, and salts thereof.

Nonionic compatibilizers include polyoxyalkylene alkyl ethers such as polyoxyethylene alkyl ethers and polyoxyethylene-polyoxypropylene alkyl ethers; aromatic group-containing ethers such as polyoxyethylene alkyl phenyl ethers and polyoxyethylene polystyryl phenyl ethers; polyoxyalkylene glycols such as polyoxyethylene-polyoxypropylene glycol; acetylene glycols such as 2,4,7,9-tetramethyl-5-decyne-4,7-diol or ethoxylate of 2,4,7,9-tetramethyl-5-decyne-4,7-diol; polyhydric alcohol fatty acid partial esters, polyoxyethylene polyhydric alcohol fatty acid partial esters, polyoxyethylene fatty acid esters, polyglycerin fatty acid esters, etc. Examples of such organic amine compounds include ester-based compatibilizers, polyoxyethylenated castor oil, alkanolamides such as fatty acid monoethanolamides, fatty acid diethanolamides, and fatty acid triethanolamides; glucoside-based compatibilizers such as alkyl glucosides and alkyl polyglucosides; alkyl amines such as monomethylamine, dimethylamine, and trimethylamine; alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine; morpholine; 2-(dimethylamino)ethanol; 2-(diethylamino)ethanol; 1-amino-2-propanol; triisopropanolamine; polyoxyethylene alkylamines; triethanolamine fatty acid partial esters; and hydroxyl-containing amine compounds such as trialkylamine oxides.

Examples of amphoteric compatibilizers include betaines such as N,N-dimethyl-N-alkyl-N-carboxymethylammonium betaine, N,N,N-trialkyl-N-sulfoalkyleneammonium betaine, N,N-dialkyl-N,N-bispolyoxyethyleneammonium sulfate betaine, and 2-alkyl-1-carboxymethyl-1-hydroxyethylimidazolinium betaine, and aminocarboxylic acids such as N,N-dialkylaminoalkylenecarboxylates.

The compatibilizer may contain the above-mentioned component (a), but alkanolamine compounds, alkanolamide compounds, and hydroxy compounds having 12 or more carbon atoms that fall under the following categories are treated as component (c) compatibilizers.
Examples of the alkanolamine compound include monoethanolamine, diethanolamine, and triethanolamine, and examples of the alkanolamide compound include monoethanolamide, diethanolamide, and triethanolamide.
Examples of hydroxy compounds having 12 or more carbon atoms include polyoxyethylene alkyl ether-based, polyoxyalkylene glycol-based, acetylene glycol-based, ester-based and glucoside-based hydroxy compounds having 12 or more carbon atoms.

Among the compatibilizers of component (c) in the remover, from the viewpoints of compatibility and ease of handling, aromatic sulfonates and hydroxyl-containing amine compounds are preferred. Specific compounds include sodium benzenesulfonate, sodium toluenesulfonate, sodium 2,4-dimethylbenzenesulfonate, sodium 2-naphthalenesulfonate, and alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine. Among these, from the viewpoint of increasing the upper limit of heating of the remover, it is more preferred to use the aromatic sulfonates having a high boiling point.
As described above, it is assumed that a compound different from component (b) is used.

As a specific example of a combination of component (b) and component (c), when an inorganic alkalizing agent is used as the alkalizing agent, at least one of an anionic compatibilizer, a cationic compatibilizer, a nonionic compatibilizer, and an amphoteric compatibilizer may be used as component (c).
When an organic alkalizing agent is used as component (b), at least one of an anionic compatibilizer, a cationic compatibilizer, a nonionic compatibilizer other than an organic amine compound, and an amphoteric compatibilizer may be used as component (c).

In the remover of the present invention, it is preferable to use an inorganic alkalizing agent as component (b) and at least one selected from aromatic sulfonates and hydroxyl group-containing amine compounds as component (c).
Among these, a combination of at least one inorganic alkalizing agent selected from sodium hydroxide and potassium hydroxide and an aromatic sulfonate such as sodium 2,4-dimethylbenzenesulfonate is preferred.
Also preferred is a combination of at least one inorganic alkalizing agent selected from sodium hydroxide and potassium hydroxide with at least one hydroxyl group-containing amine compound selected from monoethanolamine, diethanolamine, triethanolamine, morpholine, 2-(dimethylamino)ethanol, 2-(diethylamino)ethanol, 1-amino-2-propanol, and triisopropanolamine, and among these, a combination of at least one inorganic alkalizing agent selected from sodium hydroxide and potassium hydroxide with at least one hydroxyl group-containing amine compound selected from monoethanolamine and diethanolamine is particularly preferred.

In order to comprehensively dissolve various additives in the remover, two or more of the above compatibilizers may be used in combination.
The content of the compatibilizer in the remover is preferably in the range of 1 to 40% by mass. Within this range, sufficient cleaning properties can be obtained. From the above viewpoints, the content of the compatibilizer in the remover is more preferably in the range of 5 to 35% by mass, and even more preferably in the range of 8 to 30% by mass.

The silicone release layer remover of the present invention is preferably a water-based remover. A water-based remover is prepared by dissolving the above-mentioned components (a) to (c) in water and diluting them. Water-based removers are relatively safe because they can increase the flash point, and are also advantageous in that water can be used in the rinsing step described below.

The silicone release layer remover of the present invention can contain various additives in addition to the above components (a) to (c), such as antioxidants, rust inhibitors, pH adjusters, preservatives, viscosity adjusters, and defoamers.

<Laminated polyester film>
The laminated polyester film in the present invention refers to a film in which a silicone release layer is laminated on the surface of a polyester film, which is a base film.
The polyester film may have a single layer structure or a multi-layer structure. In the case of a multi-layer structure, it may have a two-layer structure, a three-layer structure, or a four-layer structure or more, and the number of layers is not particularly limited.
The polyester film may be a stretched film such as a biaxially stretched film, or may be an unstretched film.

The polyester constituting the polyester film is not particularly limited, and any polyester available on the market can be appropriately used. Specifically, polyesters obtained by polycondensation of dicarboxylic acids and diols can be mentioned, and the dicarboxylic acid is preferably an aromatic dicarboxylic acid, and the diol is preferably an aliphatic glycol.
Examples of the aromatic dicarboxylic acid include terephthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid, and phthalic acid.
Examples of the aliphatic glycol component include ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, 1,4-cyclohexanedimethanol, and neopentyl glycol.

The polyester may be a homopolyester or a copolymer polyester.
The polyester may also contain a third component other than the aromatic dicarboxylic acid and the glycol as a copolymer component.
Specific examples of polyesters include polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, polybutylene-2,6-naphthalate, and the like, with polyethylene terephthalate being preferred among these.
These may also be polyester copolymers. For example, polyethylene terephthalate may have dicarboxylic acid units other than terephthalic acid at about 30 mol % or less of the dicarboxylic acid units, and may have diol units other than ethylene glycol at about 30 mol % or less of the diol units.

The silicone release layer is a layer provided to impart releasability to a polyester film, and is, for example, a layer provided on a release film used in forming green sheets used in the manufacture of ceramic electronic components, adhesive separators for optical components used in the manufacture of flat panel displays such as polarizing plates and optical filters, etc. The material constituting the silicone release layer is not particularly limited, and examples thereof include those mainly composed of cured silicone resin, and modified silicone resins obtained by graft polymerization with urethane resin, epoxy resin, etc.
As such a curable silicone resin, any curing reaction type can be used, such as a solvent addition type, a solvent condensation type, a solvent UV curable type, a solventless addition type, a solventless condensation type, a solventless UV curable type, or a solventless electron beam curable type.

In the HSP [δd ₁ , δp ₁ , δh ₁ ] of the silicone release layer surface in the laminated polyester film, the dispersion term δd ₁ is preferably 16.0 to 23.0 MPa ^0.5 , more preferably 17.0 to 22.0 ^{MPa 0.5} , even more preferably 18.0 to 21.0 MPa ^0.5 , and particularly preferably 19.0 to 20.0 ^{MPa 0.5} .
The polar term δp ₁ is preferably 2.0 to 9.0 MPa ^0.5 , more preferably 3.0 to 8.0 MPa ^0.5 , further preferably 4.0 to 7.0 MPa ^0.5 , and particularly preferably 5.0 to 6.0 ^{MPa 0.5} .
Furthermore, the hydrogen bond parameter δh ₁ is preferably 5.0 to 12.0 ^{MPa 0.5} , more preferably 6.0 to 11.0 ^{MPa 0.5} , even more preferably 7.0 to 10.0 MPa ^0.5 , and particularly preferably 8.0 to 9.0 ^{MPa 0.5} .
When δd ₁ , δp ₁ and δh ₁ of the silicone release layer are within such ranges, the solubility with component (a) in the silicone release layer remover of the present invention is increased, making it possible to easily remove the silicone release layer.

The thickness of the silicone release layer is not particularly limited, but from the viewpoint of the permeability of the silicone release layer remover, it is preferably 0.003 to 1.0 μm, more preferably 0.005 to 0.5 μm, and even more preferably 0.01 to 0.4 μm.

[Method for Removing Silicone Release Layer]
According to another aspect of the present invention, there is provided a method for removing a silicone release layer from a laminated polyester film having a silicone release layer on the surface of a polyester film (hereinafter also referred to as "this removal method").
In this removal method, the silicone release layer is removed from the laminated polyester film by cleaning the laminated polyester film with the above-mentioned remover.
Specific and preferred embodiments of the remover are the same as those described above, and all of these can be incorporated herein by reference.
Moreover, specific and preferred aspects of the washing are the same as those of the washing step described below, and all of these can be used.
This removal method makes it possible to easily remove the silicone release layer from the laminated polyester film, and efficiently recover the polyester film from the laminated polyester film.

[Method of manufacturing recycled polyester]
The method for producing recycled polyester of the present invention (hereinafter sometimes simply referred to as the "production method") includes a washing step and a recovery step.
<Cleaning process>
The cleaning step according to the present invention is a step of removing the silicone release layer of the laminated film using the remover. Examples of the removal method include an immersion method in which the film is immersed in a cleaning tank containing the remover, a coating method in which the remover in a solution state is applied, and a spraying method in which the remover in a solution state or vaporized remover is sprayed. Among these, the immersion method is preferred from the viewpoint of the permeability of the remover into the silicone release layer.

The temperature of the remover in the immersion method is preferably room temperature (20° C.) or higher. At room temperature (20° C.) or higher, the viscosity of the remover is low and it is easy to penetrate into the silicone release layer, so good cleaning properties can be obtained. From the above viewpoints, the temperature of the remover in the immersion method is more preferably 40° C. or higher, even more preferably 50° C. or higher, and particularly preferably 60° C. or higher.
The upper limit of the temperature of the remover is preferably a temperature equal to or lower than the boiling point when the remover is used in a solution state. In the case of an aqueous remover, which is a preferred embodiment of the present application, the upper limit is preferably 100° C. or lower, and more preferably 90° C. or lower.
In addition, even in the case of a method other than the immersion method, the temperature of the remover during cleaning is the same as above.
In addition, in the cleaning by the immersion method, microwave irradiation may be performed for the purpose of improving the removal rate of the silicone release layer.

The pH of the remover is preferably 12 or higher from the viewpoint of cleaning performance, and more preferably 13 or higher.

The immersion time is preferably 1 second or more and 30 minutes or less. If it is 1 second or more, the remover will sufficiently penetrate into the silicone release layer, and cleaning properties will be exhibited. On the other hand, if it is 30 minutes or less, the polyester film substrate will not be excessively dissolved, and the amount of polyester obtained upon recovery can be secured. From the above viewpoints, it is more preferable that it be 15 seconds or more and 20 minutes or less, even more preferable that it be 30 seconds or more and 10 minutes or less, and particularly preferable that it be 1 minute or more and 5 minutes or less.

The specific aspects of the cleaning process depend on the shape of the laminated polyester film waste material.

<Unwinding process>
When the waste laminated polyester film is in a roll form, it is preferable to have an unwinding step. More specifically, it is a step in which an unwinding device is installed in front of a cleaning tank containing a remover, the laminated polyester film is unwound from the device, and introduced into the cleaning tank for cleaning. Then, it is preferable to continuously move to the next recovery step.
When the laminated polyester film is in the form of a roll, in the cleaning step, equipment equipped with a physical means such as a roll brush, ultrasonic waves, micro/nano bubbles, a water flow, or compressed cold air may be provided for the purpose of efficiently removing the silicone release layer from the laminated polyester film.

<Cutting process>
When the laminated polyester film, which is the waste material, is in a lump form, it is preferable to have a cutting process. More specifically, it is a process in which a cutting device is installed before the cleaning process, and the laminated polyester film is cut into flakes and introduced into the cleaning tank. By cutting into flakes, the contact area between the laminated polyester film and the remover is increased, making it easier for the remover to penetrate, and the silicone release layer can be removed efficiently. In addition, the silicone release layer can be removed efficiently because friction occurs between the flaky laminated polyester films. In this embodiment, a method of continuously introducing the flaky laminated polyester film into the cleaning tank using a belt conveyor or the like is preferable. By adopting such an embodiment, cleaning can be performed with high productivity.
In this embodiment, the washing can also be carried out in a batch manner.

<Recovery process>
The method for producing recycled polyester of the present invention includes a recovery step of recovering the polyester film, which is the base film, after the washing step.
It is also preferable to have a rinsing step and a drying step prior to the recovery step.As the recovery method, an appropriate method can be selected depending on the shape of the laminated polyester film as the waste material.

If the waste laminated polyester film is in roll form, it can be efficiently recovered by continuously processing it in a roll-to-roll manner, and then winding it up after passing through the appropriate cleaning, rinsing, and drying processes.

If the laminated polyester film waste is in the form of lumps, as described above, it is preferable to have a cutting process before the cleaning process, and to use a belt conveyor or the like to continuously pass the film through a rinsing process and a drying process to recover the polyester in flake form.

The polyester film recovered as described above is advantageously pelletized after recovery in terms of handling.

<Rinsing process>
In the present invention, it is preferable to have a rinsing step of washing away the removing agent after the cleaning step and before the recovery step. Specifically, this refers to a step of washing away the removing agent adhering to the polyester film from which the silicone release layer has been removed, with a rinsing liquid.

There are no particular limitations on the rinsing liquid as long as it can wash away the remover, but when using a water-based remover, which is a preferred embodiment of the present invention, water can be used in the rinsing step.

The temperature for the rinsing step is preferably around room temperature, more specifically 5 to 50°C, and more preferably 5 to 30°C, from the viewpoint of efficient rinsing.

Methods for washing off the remover include the spray method, in which a rinse liquid is sprayed onto the polyester film from which the silicone release layer has been removed, and the immersion method, in which the polyester film is immersed in a rinse tank containing a rinse liquid. However, if a remover that does not need to be washed off is used, the rinsing process can be omitted.

In some cases, the silicone release layer that has peeled off from the polyester film is also washed away together with the remover. The organic solvent or water used in the rinsing process and the material that made up the silicone release layer are then separated, and the organic solvent and water can be reused in the rinsing process, and the material that made up the silicone release layer can also be reused.

<Drying process>
After the rinsing step, a drying step is preferably performed. The drying step can remove the remover and/or the rinsing liquid remaining on the polyester film. When the rinsing step is omitted, the drying step is preferably performed after the cleaning step.

The conditions for the drying process are not particularly limited, and drying is usually performed at 70 to 150°C for about 1 to 30 minutes. As for the drying method, a general method such as heating and drying using an infrared heater or oven, hot air drying using a hot air dryer, or microwave heating and drying can be used.

<Recycled polyester product manufacturing process>
In the manufacturing method of the present invention, it is preferable to have a recycled polyester product manufacturing step in which the polyester film recovered in the recovery step is recycled (reused) as a raw material to manufacture a recycled polyester product. In addition, it is preferable that, in the preceding stage of the manufacturing step, the polyester is pelletized in a pellet manufacturing step described below, and the pellets are used to manufacture the recycled polyester product described below.

<Pellet manufacturing process>
The dried polyester film is preferably processed into pellets by a pellet manufacturing process. In particular, when the laminated polyester film as a waste material is in a lump form, it is cut as described above, and the resulting recycled polyester is in a flake form. The flake-form polyester is pelletized to remarkably improve its handling properties.
Pellets are advantageous not only in terms of handling, but also in terms of ease of storage and subsequent processing.

[Recycled polyester products]
The polyester film obtained by the method for producing recycled polyester of the present invention can be used as a polyester raw material and can be reused as a so-called recycled polyester product. Specifically, the recovered polyester can be pelletized and stored as pelletized polyester (polyester product).
The recovered polyester can also be molded into various polyester products such as polyester films by melt extrusion or the like.
In addition, the recovered polyester is preferably pelletized and then molded into various products, because of ease of production.

It can be used in the same applications as ordinary polyester products, for example, as a polyester film, which is a base film. By forming a functional layer on the base film, it can also be reused as a laminate film.

The functional layer is not particularly limited in terms of its constituent components, but examples thereof include an adhesive layer, a hard coat layer, a release layer, a decorative layer, a light-shielding layer, an ultraviolet-shielding layer, an easy-adhesion layer (primer layer), an antistatic layer, a refractive index adjustment layer, and an oligomer sealing layer.

Recycled polyester can be mixed with polyester produced by conventional methods, and multilayer films can be made using recycled polyester and polyester produced by conventional methods.

Recycled polyester products can be used for a variety of purposes other than film, such as producing PET bottles, polyester fibers, polyester sheets, and polyester containers.

In addition, the peeled silicone release layer can also be collected and reused if necessary.

<<Term explanation>>
In the present invention, the term "film" includes the term "sheet", and the term "sheet" includes the term "film".
In the present invention, when it is described as "X to Y" (X and Y are arbitrary numbers), unless otherwise specified, it includes the meaning of "X or more and Y or less", as well as the meaning of "preferably larger than X" or "preferably smaller than Y".
In addition, when it is stated that the amount is "X or more" (X is any number), it also means that the amount is "preferably greater than X" unless otherwise specified, and when it is stated that the amount is "Y or less" (Y is any number), it also means that the amount is "preferably smaller than Y" unless otherwise specified.

Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples described below.

<Evaluation method>
(1) Intrinsic Viscosity 1 g of polyester was precisely weighed, dissolved in 100 ml of a mixed solvent of phenol/tetrachloroethane = 50/50 (mass ratio), and the intrinsic viscosity was measured at 30°C.

(2) Cleaning test The remover prepared in each Example and Comparative Example was placed in a 30 ml container, and a 4×3 cm laminated polyester film was immersed in the remover. The temperature of the remover and the immersion time were as shown in the table.

(3) Removal rate of silicone release layer: X-ray fluorescence analysis The surface of the laminated polyester film after cleaning was quantitatively analyzed for Si element using an X-ray fluorescence analyzer (XRF, Shimadzu Corporation "EDX-8000").
The removal rate of the silicone release layer was measured by setting the amount of Si element on the surface of the laminated polyester film before cleaning to 100% and the amount of Si element on a plain film of the laminated polyester film that was not coated with a silicone release layer to 0%.
◎(very good); Removal rate 85-100%
○ (good); Removal rate 70-84%
×(poor); Removal rate 0-69%

(4) HSP of the silicone release layer surface [δd ₁ , δp ₁ , δh ₁ ]
A 2.0 μL droplet of a solvent selected according to Table 1 above was dropped onto the surface of the silicone release layer, and the contact angle after 30 seconds was recorded. Measurements were performed five times for each solvent, and the average value of the three data points excluding the largest and smallest values was taken as the contact angle for that solvent.
The solvent species with a small contact angle was considered as a good solvent, and the solvent species with a large contact angle was considered as a poor solvent, and the interaction sphere and its center, the HSP, were calculated. HSPiP was used for the calculation, and the threshold values for the good solvent and poor solvent were determined so that the fitting value of the calculated interaction sphere was closest to 1.
The calculated HSP [δd ₁ , δp ₁ , δh ₁ ] of the silicone release layer surface is shown in Table 2. The threshold value for the good solvent and poor solvent in the calculation was 78°. The radius of the interaction sphere was 3.6, and the fitting was 1.000.
The silicone release layer used in the measurements was a commercially available product ("MRF38" manufactured by Mitsubishi Chemical Corporation), and the polyethylene terephthalate film had a thickness of 38 μm and an intrinsic viscosity of 0.57 dl/g.

(5) HSP distance (Ra)
Using the HSP value of the component (a) and the HSP value of the surface of the silicone release layer measured by the above method, the HSP distance (Ra) was calculated according to the following formula.
Ra={4×(δd ₁ - δd ₂ ) ² + (δp ₁ - δp ₂ ) ² + (δh ₁ - δh ₂ ) ² } ^0.5
Here, δd ₁ , δp ₁ and δh ₁ respectively represent δd, δp and δh of the silicone release layer surface, and δd ₂ , δp ₂ and δh ₂ respectively represent δd, δp and δh of component (a) in the silicone release layer remover.

<Laminated polyester film>
Laminated polyester film having a silicone release layer: a commercially available product ("MRF75" manufactured by Mitsubishi Chemical Corporation) was used.
The polyethylene terephthalate film had a thickness of 75 μm and an intrinsic viscosity of 0.57 dl/g.
The silicone release layer of the above-mentioned "MRF38" and "MRF75" is the same.

[Example 1]
A remover was prepared by mixing 40 parts by mass of benzylamine as component (a), 5 parts by mass of potassium hydroxide as component (b), and 55 parts by mass of water as the other component.
The above laminated polyester film was used for cleaning, and the removal rate of the silicone release layer was evaluated by immersing it in a remover heated to 80° C. for 5 minutes. The results are shown in Table 3.

[Example 2]
A remover was prepared by mixing 40 parts by weight of benzyl alcohol as component (a), 5 parts by weight of potassium hydroxide as component (b), and 55 parts by weight of water as the other component. The removal rate of the silicone release layer was evaluated in the same manner as in Example 1. The results are shown in Table 3.

[Example 3]
A remover was prepared by mixing 40 parts by mass of toluene as component (a), 5 parts by mass of potassium hydroxide as component (b), and 55 parts by mass of water as the other component.
Using the above laminated polyester film, the removal rate of the silicone release layer was evaluated in the same manner as in Example 1. The results are shown in Table 3.

[Example 4]
A remover was prepared by mixing 33 parts by mass of benzylamine as component (a), 5 parts by mass of potassium hydroxide as component (b), 26 parts by mass of sodium 2,4-dimethylbenzenesulfonate as component (c), and 36 parts by mass of water as another component.
The above laminated polyester film was immersed in a remover heated to 80° C. for 1 minute and 5 minutes for cleaning, and the removal rate of the silicone release layer was evaluated. The results are shown in Table 3.

[Example 5]
A remover was prepared by mixing 41.3 parts by mass of benzyl alcohol as component (a), 5 parts by mass of potassium hydroxide as component (b), 17.6 parts by mass of sodium 2,4-dimethylbenzenesulfonate as component (c), and 36.1 parts by mass of water as another component.
Using the above laminated polyester film, the removal rate of the silicone release layer was evaluated in the same manner as in Example 4. The results are shown in Table 3.

[Comparative Example 1]
A remover was prepared by mixing 40 parts by mass of N,N-dimethylformamide (DMF) as component (a), 5 parts by mass of potassium hydroxide as component (b), and 55 parts by mass of water as the other component.
Using the above laminated polyester film, the removal rate of the silicone release layer was evaluated in the same manner as in Example 1. The results are shown in Table 3.

[Comparative Example 2]
A remover was prepared by mixing 40 parts by mass of acetonitrile as component (a), 5 parts by mass of potassium hydroxide as component (b), and 55 parts by mass of water as the other component.
Using the above laminated polyester film, the removal rate of the silicone release layer was evaluated in the same manner as in Example 1. The results are shown in Table 3.

[Comparative Example 3]
A remover was prepared by mixing 5 parts by mass of potassium hydroxide as component (b) and 95 parts by mass of water as the other component.
Using the above laminated polyester film, the removal rate of the silicone release layer was evaluated in the same manner as in Example 1. The results are shown in Table 3.

As shown in Table 3, the silicone release layer could be easily removed from the laminated polyester film by cleaning the laminated polyester film with a remover containing component (a).
This is because, if the difference in polarity δp between component (a) and the surface of the silicone release layer is less than 8.0 MPa ^0.5 , the affinity between component (a) and the surface of the silicone release layer is increased, and the solubility is improved. As a result, a penetration effect due to the solubility is obtained, and the silicone release layer can be easily removed.

Claims (44)

A remover for removing a silicone release layer from a laminated polyester film having a silicone release layer on the surface of the polyester film, comprising:
A silicone release layer remover comprising a component (a) that satisfies the relationship of the following formula (1) and the following formula (2):
|δp ₁ −δp ₂ |<8.0MPa ^0.5 ...(1)
(wherein δp ₁ represents the polar term δp of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δp ₂ represents the polar term δp of component (a).)
|δh ₁ −δh ₂ |<9.0MPa ^0.5 ...(2)
(wherein δh ₁ represents the hydrogen bond term δh of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δh ₂ represents the hydrogen bond term δh of component (a).) A remover for removing a silicone release layer from a laminated polyester film having a silicone release layer on the surface of the polyester film, comprising:
Contains a component (a) that satisfies the relationship of the following formula (1),
A silicone release layer remover, wherein the component (a) is at least one member selected from the group consisting of aromatic alcohols, aromatic amines, and aromatic hydrocarbons.
|δp ₁ −δp ₂ |<8.0MPa ^0.5 ...(1)
(wherein δp ₁ represents the polar term δp of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δp ₂ represents the polar term δp of component (a).) A remover for removing a silicone release layer from a laminated polyester film having a silicone release layer on the surface of the polyester film, comprising:
Contains a component (a) that satisfies the relationship of the following formula (1),
A silicone release layer remover, wherein the dispersion term _δd2 of the component (a) is 16.0 to 22.0 MPa ^0.5.
|δp ₁ −δp ₂ |<8.0MPa ^0.5 ...(1)
(wherein δp ₁ represents the polar term δp of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δp ₂ represents the polar term δp of component (a).) The silicone release layer remover according to claim 2 or 3, wherein the component (a) further satisfies the relationship of the following formula (2):
|δh ₁ −δh ₂ |<11.0MPa ^0.5 ...(2)
(wherein δh ₁ represents the hydrogen bond term δh of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δh ₂ represents the hydrogen bond term δh of component (a).) The silicone release layer remover according to any one of claims 1 to 4, wherein the component (a) further satisfies the relationship of the following formula (3):
Ra={4×(δd ₁ - δd ₂ ) ² + (δp ₁ - δp ₂ ) ² + (δh ₁ - δh ₂ ) ² } ^0.5 ≦9.2...(3)
(wherein Ra represents the HSP distance, δd ₁ , δp ₁ and δh ₁ represent the δd, δp and δh of the silicone release layer surface, respectively, in the Hansen solubility parameters [δd, δp, δh], and δd ₂ , δp ₂ and δh ₂ represent the δd, δp and δh of component (a), respectively.) The silicone release layer remover according to any one of claims 1, 2, 4 and 5, wherein the dispersion term _δd2 of component (a) is 15.0 to 22.0 ^{MPa 0.5} . The silicone release layer remover according to any one of claims 1 to 6, wherein the polar term _δp2 of component (a) is 0.0 to 8.0 MPa ^0.5 . The silicone release layer remover according to any one of claims 1 to 7, wherein the hydrogen bond term _δh2 of component (a) is 1.0 to 16.0 MPa ^0.5 . The silicone release layer remover according to any one of claims 1 and 3 to 8, wherein the component (a) is at least one selected from the group consisting of aliphatic alcohols, aromatic alcohols, aromatic amines, and aromatic hydrocarbons. The silicone release layer remover according to any one of claims 1 to 9, further comprising component (b) an alkalizing agent. The silicone release layer remover according to any one of claims 1 to 10, further comprising component (c) a compatibilizer. The silicone release layer remover according to any one of claims 1 to 11, wherein the silicone release layer surface has a dispersion term δd _{1 of} 16.0 to 23.0 MPa ^0.5 , a polar term δp ₁ of 2.0 to 9.0 MPa ^0.5 , and a hydrogen bond term δh 1 of 5.0 to 12.0 ^{MPa 0.5} . The silicone release layer remover according to any one of claims 1 to 12, wherein the thickness of the silicone release layer is 0.003 to 1.0 μm. A method for removing a silicone release layer, comprising cleaning a laminated polyester film having a silicone release layer on the surface of the polyester film with a remover containing a component (a) that satisfies the relationship between the following formulas (1) and (2):
|δp ₁ −δp ₂ |<8.0MPa ^0.5 ...(1)
(wherein δp ₁ represents the polar term δp of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δp ₂ represents the polar term δp of component (a).)
|δh ₁ −δh ₂ |<9.0MPa ^0.5 ...(2)
(wherein δh ₁ represents the hydrogen bond term δh of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δh ₂ represents the hydrogen bond term δh of component (a).) A method for removing a silicone release layer, comprising cleaning a laminated polyester film having a silicone release layer on the surface of the polyester film with a remover containing component (a) that satisfies the relationship of the following formula (1), wherein the component (a) is at least one selected from the group consisting of aromatic alcohols, aromatic amines, and aromatic hydrocarbons:
|δp ₁ −δp ₂ |<8.0MPa ^0.5 ...(1)
(wherein δp ₁ represents the polar term δp of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δp ₂ represents the polar term δp of component (a).) A method for removing a silicone release layer, comprising cleaning a laminated polyester film having a silicone release layer on the surface of the polyester film with a remover containing a component (a) that satisfies the relationship of the following formula (1), and the dispersion term _δd2 of the component (a) is 16.0 to 22.0 ^MPa0.5 :
|δp ₁ −δp ₂ |<8.0MPa ^0.5 ...(1)
(wherein δp ₁ represents the polar term δp of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δp ₂ represents the polar term δp of component (a).) The method for removing a silicone release layer according to claim 15 or 16, wherein the component (a) further satisfies the relationship of the following formula (2):
|δh ₁ −δh ₂ |<11.0MPa ^0.5 ...(2)
(wherein δh ₁ represents the hydrogen bond term δh of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δh ₂ represents the hydrogen bond term δh of component (a).) The method for removing a silicone release layer according to any one of claims 14 to 17, wherein the component (a) satisfies the relationship of the following formula (3):
Ra={4×(δd ₁ - δd ₂ ) ² + (δp ₁ - δp ₂ ) ² + (δh ₁ - δh ₂ ) ² } ^0.5 ≦9.2...(3)
(wherein Ra represents the HSP distance, δd ₁ , δp ₁ and δh ₁ represent the δd, δp and δh of the silicone release layer surface, respectively, in the Hansen solubility parameters [δd, δp, δh], and δd ₂ , δp ₂ and δh ₂ represent the δd, δp and δh of component (a), respectively.) The method for removing a silicone release layer according to any one of claims 14, 15, 17 and 18, wherein the dispersion term _δd2 of component (a) is 15.0 to 22.0 ^{MPa 0.5} . The method for removing a silicone release layer according to any one of claims 14 to 19, wherein the polar term _δp2 of component (a) is 0.0 to 8.0 MPa ^0.5 . The method for removing a silicone release layer according to any one of claims 14 to 20, wherein the hydrogen bond term _δh2 of component (a) is 1.0 to 16.0 ^{MPa 0.5} . The method for removing a silicone release layer according to any one of claims 14 and 16 to 21, wherein the component (a) is at least one selected from the group consisting of aliphatic alcohols, aromatic alcohols, aromatic amines, and aromatic hydrocarbons. The method for removing a silicone release layer according to any one of claims 14 to 22, wherein the remover further contains component (b) an alkalizing agent. The method for removing a silicone release layer according to any one of claims 14 to 23, wherein the remover further contains component (c) a compatibilizer. The silicone release layer surface has a dispersion term δd ₁ of 16.0 to 23.0 MPa ^0.5 , a polar term δp ₁ of 2.0 to 9.0 MPa ^0.5 , and a hydrogen bond term δh ₁ of 5.0 to 12.0 ^{MPa 0.5} . The method for removing a silicone release layer according to any one of claims 14 to 25, wherein the thickness of the silicone release layer is 0.003 to 1.0 μm. a cleaning step of cleaning a laminated polyester film having a silicone release layer on a surface of the polyester film with a remover containing a component (a) that satisfies the relationship of the following formula (1) and the following formula (2);
and recovering the washed polyester film.
|δp ₁ −δp ₂ |<8.0MPa ^0.5 ...(1)
(wherein δp ₁ represents the polar term δp of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δp ₂ represents the polar term δp of component (a).)
|δh ₁ −δh ₂ |<9.0MPa ^0.5 ...(2)
(wherein δh ₁ represents the hydrogen bond term δh of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δh ₂ represents the hydrogen bond term δh of component (a).) A laminated polyester film having a silicone release layer on the surface of the polyester film,
a cleaning step of cleaning with a remover containing a component (a) that satisfies the relationship of the following formula (1), the component (a) being at least one selected from the group consisting of aromatic alcohols, aromatic amines, and aromatic hydrocarbons;
and recovering the washed polyester film.
|δp ₁ −δp ₂ |<8.0MPa ^0.5 ...(1)
(wherein δp ₁ represents the polar term δp of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δp ₂ represents the polar term δp of component (a).) A laminated polyester film having a silicone release layer on the surface of the polyester film,
A cleaning step of cleaning with a remover containing a component (a) that satisfies the relationship of the following formula (1), and the dispersion term _δd2 of the component (a) is 16.0 to 22.0 ^MPa0.5;
and recovering the washed polyester film.
|δp ₁ −δp ₂ |<8.0MPa ^0.5 ...(1)
(wherein δp ₁ represents the polar term δp of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δp ₂ represents the polar term δp of component (a).) The method for producing recycled polyester according to claim 28 or 29, wherein the component (a) further satisfies the following formula (2):
|δh ₁ −δh ₂ |<11.0MPa ^0.5 ...(2)
(wherein δh ₁ represents the hydrogen bond term δh of the silicone release layer surface in the Hansen solubility parameters [δd, δp, δh], and δh ₂ represents the hydrogen bond term δh of component (a).) The method for producing recycled polyester according to any one of claims 27 to 30, wherein the component (a) satisfies the following formula (3):
Ra={4×(δd ₁ - δd ₂ ) ² + (δp ₁ - δp ₂ ) ² + (δh ₁ - δh ₂ ) ² } ^0.5 ≦9.2...(3)
(wherein Ra represents the HSP distance, δd ₁ , δp ₁ and δh ₁ represent the δd, δp and δh of the silicone release layer surface, respectively, in the Hansen solubility parameters [δd, δp, δh], and δd ₂ , δp ₂ and δh ₂ represent the δd, δp and δh of component (a), respectively.) The method for producing recycled polyester according to any one of claims 27, 28, 30 and 31, wherein the dispersion term _δd2 of the component (a) is 15.0 to 22.0 ^{MPa 0.5} . The method for producing recycled polyester according to any one of claims 27 to 32, wherein the polar term _δp2 of the component (a) is 0.0 to 8.0 MPa ^0.5 . The method for producing recycled polyester according to any one of claims 27 to 33, wherein the hydrogen bond parameter _δh2 of the component (a) is 1.0 to 16.0 ^{MPa 0.5} . The method for producing recycled polyester according to any one of claims 27 and 29 to 34, wherein the component (a) is at least one selected from the group consisting of aliphatic alcohols, aromatic alcohols, aromatic amines, and aromatic hydrocarbons. The method for producing recycled polyester according to any one of claims 27 to 35, wherein the remover further contains component (b) an alkalizing agent. The method for producing recycled polyester according to any one of claims 27 to 36, wherein the remover further contains component (c) a compatibilizer. The method for producing recycled polyester according to any one of claims 27 to 37, wherein the silicone release layer surface has a dispersion term δd _{1 of} 16.0 to 23.0 MPa ^0.5 , a polar term δp ₁ of 2.0 to 9.0 MPa ^0.5 , and a hydrogen bond term δh 1 of 5.0 to 12.0 MPa ^0.5 . The method for producing recycled polyester according to any one of claims 27 to 38, wherein the silicone release layer has a thickness of 0.003 to 1.0 μm. The method for producing recycled polyester according to any one of claims 27 to 39 further comprises a manufacturing process for producing a recycled polyester product using the polyester film recovered in the recovery process as a raw material. The method for producing recycled polyester according to claim 40 , wherein the production process includes a pellet production process for pelletizing the washed polyester film. The method for producing recycled polyester according to any one of claims 27 to 41, further comprising a rinsing step for washing away any remover adhering to the polyester film after cleaning in the cleaning step. The method for producing recycled polyester according to any one of claims 27 to 42, further comprising an unwinding process or a cutting process prior to the washing process. The method for producing recycled polyester according to any one of claims 27 to 43, which is carried out by a roll-to-roll method.