JP6054837B2 - Cellulose ester recovery method and solution casting method - Google Patents

Description

  The present invention relates to a cellulose ester recovery method for efficiently and effectively recovering a cellulose ester from a material having a multilayer structure including a cellulose ester layer and a hard coat, and a solution film forming method using the recovered cellulose ester.

  Cellulose ester films formed from cellulose esters are excellent in transparency, toughness, flame retardancy, optical isotropy, and the like, and are therefore used in functional sheets for various optical applications. Examples of the functional sheet include a sheet used for a liquid crystal display such as a hard coat sheet, and a cellulose ester film is used as a base material of such a functional sheet. Thus, the functional sheet has a multilayer structure including the base material and the functional layer.

  When a cellulose ester film is used as the base material of the hard coat sheet, a hard coat is applied to the film surface of the cellulose ester film. The hard coat is usually formed by coating.

  A functional sheet such as a hard coat sheet is produced by cutting out a predetermined size from, for example, a long functional film made larger than the size to be used. It is desired to recycle the surplus that has been cut off against the background of recent waste problems.

  Therefore, various methods for recovering cellulose from a multilayer material having a cellulose ester layer have been proposed. For example, Patent Document 1 removes at least one of an undercoat layer, a backing layer, an alignment film, and an optically anisotropic layer formed on a cellulose ester layer by enzymatic decomposition. The cellulose ester layer contains an additive, and in the method of Patent Document 1, the cellulose ester is recovered by decomposing the additive with an oxidizing agent such as hydrogen peroxide after enzymatic degradation.

  Moreover, patent document 2 has proposed the reuse method for reusing a cellulose ester for the film use from the cellulose-ester molded object which consists of a predetermined cellulose ester. This method is a method in which the cellulose ester molded product is subjected to an oxidative bleaching treatment, followed by a swelling treatment or a cellulase treatment after the oxidative bleaching treatment.

  Moreover, patent document 3 scrapes off a fatty acid ester layer from a multilayer material provided with a fatty acid ester layer on a cellulose ester layer, and collect | recovers cellulose esters. In the method of Patent Document 3, the fatty acid ester is scraped off by bringing a granule containing diatomaceous earth and a small piece of a multilayer material into contact with each other in water.

  Patent Document 4 collects a cellulose ester by removing a functional layer by sequentially providing a multilayer material including a cellulose ester layer and a functional layer to a predetermined absorption process, a decomposition process, and a cleaning and polishing process. .

  Patent Document 5 removes a functional layer by sequentially providing a multilayer material including a functional layer having high solvent resistance on a cellulose ester layer to a predetermined dissolution process, a centrifugal separation process, and a spraying process. The cellulose ester is recovered.

JP 2004-203963 A JP 7-286068 A JP 2008-129265 A JP 2011-052114 A JP 2012-057077 A

  However, according to the method of Patent Document 1, there is a problem that the hard coat cannot be completely removed, or even if the hard coat can be removed, it takes a long time to remove. In addition, since the hard coat is formed by crosslinking by UV (ultraviolet) curing, the hard coat cannot be hydrolyzed even if it is subjected to oxidative bleaching treatment, swelling treatment and cellulase treatment as in the method of Patent Document 2. In other words, the hard coat cannot be removed.

  Further, according to the method of Patent Document 3, even if the hard coat is removed, it takes a lot of time to scrape from the cellulose ester. Furthermore, according to the method of Patent Document 3, the cellulose ester layer is also scraped, the loss of cellulose ester is large, and the yield of cellulose ester is low.

  According to the method of Patent Document 4, it is difficult to remove a layer having a cross-linked molecular structure. Therefore, generally, a hard coat having a cross-linked molecular structure cannot be completely removed. For this reason, even if the cellulose ester is recovered, the purity is low.

  Moreover, when providing functional layers, such as an optical anisotropic layer, the film surface of a cellulose-ester film may be saponified and a functional layer may be provided on the produced | generated saponified layer. Such a saponified layer cannot be removed by the methods of Patent Document 1 and Patent Document 5. In the method of Patent Document 3, even if the saponified layer is removed, it takes a lot of time to scrape off. Furthermore, in the methods of Patent Document 3 and Patent Document 4, the cellulose ester layer is also scraped, and the yield of cellulose ester is low.

  Therefore, the present invention solves the above-described problem, and a method for recovering cellulose ester, which recovers cellulose ester efficiently and effectively in a high yield from a multilayer material comprising a cellulose ester layer and a hard coat, and recovery An object of the present invention is to provide a solution film-forming method using a cellulose ester.

The cellulose ester recovery method of the present invention comprises decomposing and dissolving a hard coat by contacting a hard coat material comprising a cellulose ester layer and a hard coat disposed on one side of the cellulose ester layer with an aqueous alkali solution. And an alkali treatment step for saponifying the outer periphery of the cellulose ester layer to form a saponified layer, and a first washing step for removing the hard coat by washing the hard coat material after the alkali treatment step with water, After the first washing step, an saponification material comprising a cellulose ester layer and a saponification layer is brought into contact with an aqueous solution or suspension containing cellulase, thereby decomposing the saponification layer, and saponification after the enzyme treatment step. the wood by washing with water, and a second cleaning step of removing the saponification layer, cellular It is a group of enzymes Trichoderma longibrachiatum has produced, and is configured as comprising a group of enzymes Acremonium is produced.

The aqueous solution or suspension containing cellulase is a mixture of a first aqueous solution containing an enzyme group produced by Trichoderma reesei and a second aqueous solution containing an enzyme group produced by Acremonium genus. The mass ratio with the aqueous solution is preferably in the range of 2: 3 to 9: 1. The aqueous solution or suspension containing cellulase preferably contains no other degrading enzyme different from cellulase. The cellulase contains cellobiohydrolase, and the mass of the cellobiohydrolase is preferably in the range of 87% by mass to 93% by mass of the mass of the cellulase. The cellulase contains cellobiohydrolase, endorcanase, and β-glucosidase, and the sum of the mass of endorcanase and β-glucosidase with respect to the mass of cellobiohydrolase is in the range of 0.04 to 0.15. Preferably there is.

The time for the enzyme treatment step is preferably in the range of 90 minutes to 180 minutes. The mass of the cellulase is preferably in the range of 0.1% to 20% with respect to the mass of the saponification material. The hydrogen ion exponent pH of the aqueous alkali solution is preferably in the range of 12.0 to 14.0.

  The solution casting method of the present invention uses the cellulose ester recovered by the above cellulose ester recovery method as a polymer component of the dope, casts the dope onto a support, forms a casting film, The film is formed by peeling off from the support and drying.

  According to the present invention, a cellulose ester can be efficiently and effectively recovered at a high yield from a multilayer material comprising a cellulose ester layer and a hard coat. The recovered cellulose ester can be used for the film as a component of the dope.

It is a schematic plan view of a hard coat web. It is explanatory drawing of a hard coat sheet and an excess material. It is sectional drawing of an excess material. It is a flow figure which collects a cellulose ester material from surplus material. It is the schematic of the collection | recovery equipment which collect | recovers cellulose ester materials from an excess material. It is the schematic of a hard-coat removal apparatus. It is the schematic of a saponification layer removal apparatus. It is the schematic of a saponification material. It is the schematic of solution casting apparatus.

  Some film-like functional materials are formed in a long length. From this long functional material (hereinafter referred to as a functional web), a sheet having a size corresponding to the application (hereinafter referred to as a functional sheet). As such, the part that should be the product is cut out.

  For example, the hard coat sheet 71 as a functional sheet is obtained by cutting out from the hard coat web 70 as the functional web shown in FIG. 1 into a sheet shape as shown in FIG. 2 with a predetermined size. . The hard coat sheet 71 is used for various products such as a liquid crystal display. On the other hand, the surplus material 120 from which the hard coat sheet 71 is cut out from the hard coat web 70 is an object for recovering the cellulose ester. A method for recovering the cellulose ester from the surplus material 120 which is a functional material having a multilayer structure will be described below.

  The surplus material 120 has the same configuration as the hard coat sheet 71, and includes, for example, a cellulose ester layer 11 and a hard coat 121 as a functional layer, as shown in FIG. The cellulose ester is recovered from the cellulose ester layer 11. In FIG. 3, the thickness direction is indicated by an arrow T.

  The cellulose ester layer 11 is a support when the hard coat 121 is formed by coating or in use. The thickness T11 of the cellulose ester layer 11 from the viewpoint of supporting the hard coat 121 is generally in the range of 20.0 μm to 100.0 μm.

  The cellulose ester layer 11 is formed from a cellulose ester. The cellulose ester is not particularly limited, and examples thereof include cellulose acetate, cellulose acetate propionate, etc., and any one of these may be used, or a mixture of several of these may be used. Good.

  The cellulose ester layer 11 may contain various additives. Examples of the additive include fine particles as a matting agent, a plasticizer, a retardation adjusting agent, and an ultraviolet absorber.

  The hard coat 121 is provided for imparting scratch resistance and has a crosslinked molecular structure. The hard coat 121 is provided in a layered manner in close contact with one surface of the cellulose ester layer 11. The thickness T121 of the hard coat 121 is generally in the range of 2.0 μm to 20.0 μm.

  As shown in FIG. 4, the recovery flow 130 for recovering the cellulose ester from the surplus material 120 includes a crushing step 26, a hard coat removing step 131, a saponified layer removing step 21, and a drying step 22.

  The effect and efficiency of recovering the cellulose ester from the surplus material 120 is affected by the individual size of the surplus material 120. Therefore, it is preferable that the surplus material 120 is supplied to the crushing step 26, and the crushing step 26 makes a material piece (for example, a chip shape) having a predetermined size or less before being used for the hard coat removing step 131. Thereby, the effect and efficiency which collect | recover a cellulose ester improve more. However, the presence or absence of the crushing step 26 may be appropriately determined according to the target recovery effect and efficiency. The recovery effect is the yield of recovered cellulose ester.

  The hard coat removing step 131 is a step of obtaining the saponified material 138 by removing the hard coat 121 from the surplus material 120. Details of the saponification material 138 will be described later with reference to another drawing. The hard coat removing step 131 includes an alkali treatment step 132 and a saponification material cleaning step 133.

  The alkali treatment step 132 is a step in which the hard coat 121 is decomposed and dissolved with an alkaline aqueous solution (hereinafter referred to as an alkaline aqueous solution), and the saponification material 138 is generated by saponifying the outer periphery of the cellulose ester layer 11. . Although the hard coat 121 is detached from the saponification material 138 by the alkali treatment step 132, at least a part of the small pieces of the hard coat 121 once detached may adhere to the saponification material 138. There is also a hard coat 121 which remains on the saponification material 138 without being detached even if it is decomposed or dissolved. In this way, a small piece of the hard coat 121 once detached adheres to the saponification material 138, or the hard coat 121 that has been decomposed or dissolved and remains on the saponification material 138 without being detached is hereinafter referred to as crude saponification. This is referred to as material 136.

  The saponification material washing step 133 is a step of removing the hard coat 121 from the crude saponification material 136 by washing the crude saponification material 136 obtained in the alkali treatment step 132 with water. The saponification material washing step 133 includes a water washing step 137 and a dehydration step 32.

  The water washing step 137 is a step in which the crude saponification material 136 is washed with water, and the alkaline aqueous solution and the decomposed hard coat 121 are detached from the saponification material 138 and removed. The dehydration step 32 is a step of removing the water used for washing in the water washing step 137 from the saponification material 138. If the hard coat 121 remains on the saponification material 138 even after the dehydration step 32, the saponification material 138 may be used again for the water washing step 137 and the dehydration step 32 after the water washing step 137. . As described above, the hard coat removing step 131 may include a plurality of saponifying material cleaning steps 133, and the number of times the saponifying material cleaning step 133 is performed is not particularly limited.

  The saponification material 138 is obtained by removing the hard coat 121 in the saponification material cleaning step 133, and the saponification material 138 adheres to the water used in the water washing step 137 or is so-called wet contained inside. Is in a state.

  The saponified material 138 in a wet state is subjected to the saponified layer removing step 21. The saponification layer removing step 21 includes an enzyme treatment step 25 and a cellulose ester material cleaning step (hereinafter referred to as a CE material cleaning step) 27. The enzyme treatment step 25 is a step of decomposing a saponification layer 155 described later with an aqueous solution of cellulase (cellulose-degrading enzyme) (hereinafter referred to as a cellulase aqueous solution). By this decomposition, the saponified layer 155 is detached from the cellulose ester layer 11, and at least a part of the small pieces of the saponified layer 155 once detached is attached to the cellulose ester layer 11. Moreover, although it decomposes | disassembles, it may remain | survive without removing | separating from the cellulose-ester layer 11. In this way, a small piece of the saponified layer 155 once detached adheres to the cellulose ester layer 11 or the decomposed saponified layer 155 remains on the cellulose ester layer 11 without detaching. This is referred to as material 28. In the enzyme treatment step 25, a cellulase suspension (hereinafter referred to as cellulase suspension) may be used instead of the cellulase aqueous solution.

  The CE material washing step 27 is a step of removing the saponified layer 155 and small pieces thereof from the crude cellulose ester material 28 by washing the crude cellulose ester material 28 obtained in the enzyme treatment step 25 with water. The CE material cleaning step 27 includes a water washing step 31 and a dehydration step 32. The water washing step 31 is a step of washing the crude cellulose ester material 28 with water and removing the cellulase aqueous solution and the decomposed saponified layer 155 from the cellulose ester layer 11 to remove them. The dehydration step 32 is a step of removing the water used for washing in the water washing step 31 from the cellulose ester layer 11. In addition, when the saponification layer 155 remains on the cellulose ester layer 11 even after the dehydration step 32, the water washing step 31 and the dehydration step 32 after the water washing step 31 may be repeated again. As described above, the saponified layer removing step 21 may include a plurality of CE material cleaning steps 27, and the number of CE material cleaning steps 27 is not particularly limited.

  The cellulose ester layer 11 remains as the cellulose ester material by removing the saponified layer 155 in the CE material washing step 27, but the cellulose ester material is attached to the water used in the washing step 31 or contained therein. In a so-called wet state. Therefore, the cellulose ester material obtained by the CE material cleaning step 27 is hereinafter referred to as a wet cellulose ester material 33.

  The drying step 22 is a step of drying the wet cellulose ester material 33 obtained by the CE material cleaning step 27. By this drying step 22, the water adhering to the wet cellulose ester material 33 and the water contained therein are evaporated. As a result, the wet cellulose ester material 33 is dried to become the cellulose ester material 34. Thus, the cellulose ester is recovered and obtained as the cellulose ester material 34 having a certain size.

  As shown in FIG. 5, the recovery equipment 90 that recovers the cellulose ester material 34 from the surplus material 120 includes a crusher 37, a hard coat removing device 141, a saponified layer removing device 38, and a drying unit 42.

  The crusher 37 is for cutting the surplus material 120 into a smaller size, and includes a cutting machine (not shown) and a delivery machine (not shown). A cutting machine (not shown) cuts the supplied surplus material 120 into, for example, chip-shaped material pieces so that the size becomes smaller. As the cutting machine, for example, a rotary cutter or a slitter is used. The delivery machine sends the surplus material 120 cut by the cutting machine to the alkali treatment unit 142. As a sending machine, for example, an air feeding machine or the like that sends the surplus material 120 to the alkali treatment unit 142 by blowing wind on the surplus material 120 is used. If there is no crushing step 26, the crusher 37 may not be provided.

  The hard coat removing device 141 is used for the hard coat removing step 131 (see FIG. 4), and includes an alkali treatment unit 142 and a cleaning unit 41. The alkali treatment unit 142 is used in the alkali treatment step 132 to obtain the crude saponification material 136. The cleaning unit 41 provided in the hard coat removing device 141 is used in the saponification material cleaning step 133 to obtain the saponification material 138. The details of the hard coat removing device 141 will be described later with reference to another drawing.

  The saponification layer removing device 38 is used for the saponification layer removing step 21 (see FIG. 4), and has an enzyme treatment unit 39 and a cleaning unit 41. The enzyme treatment unit 39 is used in the enzyme treatment step 25 (see FIG. 4) to obtain the crude cellulose ester material 28. The cleaning unit 41 provided in the saponified layer removing device 38 is used for the CE material cleaning step 27 and is for obtaining the wet cellulose ester material 33. The details of the saponification layer removing device 38 will be described later with reference to another drawing.

  The drying unit 42 is used in the drying step 22 to dry the wet cellulose swell material 33 to obtain the cellulose ester material 34. The drying unit 42 includes a housing part (not shown) that houses the wet cellulose swell material 33, a blower part (not shown) that supplies dried gas to the housing part, and a discharge that discharges the atmosphere inside the housing part to the outside. And a mechanism (not shown). By supplying a dry gas, for example, dry air, from the blower to the housing portion in which the wet cellulose ester material 33 is housed, water attached to the wet cellulose ester material 33 and water contained therein evaporate. . The evaporated water is discharged to the outside by a discharge mechanism. By this discharge, an increase in humidity in the atmosphere in the housing portion is suppressed, and the wet cellulose ester material 33 is efficiently dried, and the cellulose ester layer 11 is obtained as the cellulose ester material 34.

  The hard coat removing device 141 will be described with reference to FIG. The alkali treatment unit 142 includes a container 146 and a temperature controller 147. In the container 146, a supply port 146a through which the surplus material 120 and the alkaline aqueous solution 148 are guided is formed at, for example, the upper part. The container 146 stores the alkaline aqueous solution 148 and is supplied with the surplus material 120. The aqueous alkali solution 148 and the surplus material 120 are in contact with each other inside the container 146. In the container 146, it is preferable to contact so that the surplus material 120 may be immersed in the aqueous alkaline solution 148.

  The hydrogen ion exponent pH of the alkaline aqueous solution 148 is preferably in the range of 11.0 or more and 14.0 or less. Thereby, the hard coat 121 is more reliably decomposed and dissolved more efficiently. The hydrogen ion exponent pH of the alkaline aqueous solution 148 is more preferably in the range of 12.0 to 14.0, and still more preferably in the range of 13.0 to 14.0. The pH of the alkaline aqueous solution 148 is adjusted by adjusting the alkali concentration.

  The alkaline aqueous solution 148 is used for decomposing and dissolving the hard coat 121 and is an aqueous solution in which an alkali is dissolved in water. As the alkali, sodium hydroxide (NaOH) is preferable.

  The alkali concentration in the aqueous alkaline solution 148 is preferably in the range of 5% to 10%. That is, when the mass of alkali is M3 and the mass of water is M4, (M3 / M4) × 100 is preferably in the range of 5% to 10%. Thereby, the hard coat 121 is more reliably decomposed and dissolved more efficiently. The alkali concentration in the aqueous alkali solution 148 is more preferably in the range of 6% to 8%.

  The contact time between the alkaline aqueous solution 148 and the surplus material 120 in the container 146, that is, the time of the alkali treatment step 132 is preferably in the range of 120 minutes to 540 minutes, and preferably in the range of 180 minutes to 360 minutes. More preferred.

  The temperature controller 147 controls the temperature inside the container 146, and thereby controls the temperature of the alkaline aqueous solution 148 and the surplus material 120 in the container 146. The temperature of the alkaline aqueous solution 148 in the alkali treatment step 132 is preferably adjusted within the range of 45 ° C. or more and 65 ° C. or less. Thereby, the hard coat 121 is decomposed more effectively and efficiently. Therefore, it is preferable to keep the temperature of the alkaline aqueous solution 148 while in contact with the hard coat 121 within the above temperature range. The temperature of the alkaline aqueous solution 148 is more preferably in the range of 50 ° C. or higher and 60 ° C. or lower.

  The alkali treatment unit 142 preferably includes a stirrer 150 for stirring the mixture of the alkaline aqueous solution 148 and the surplus material 120. The stirrer 150 includes a stirring blade 150a and a rotating shaft 150b disposed inside the container 146, and a controller 150c. The rotating shaft 150b is rotated in the circumferential direction at a predetermined speed by the controller 150c. The stirring blade 150a is fixed to the rotating shaft 150b and rotates integrally with the rotating shaft 150b. By the rotation of the stirring blade 150a, the mixture of the alkaline aqueous solution 148 and the surplus material 120 is stirred, and the hard coat 121 is more reliably decomposed and dissolved more reliably.

  The container 146 has an openable / closable discharge port 146b for discharging the alkaline aqueous solution 148 to the outside, for example, at the bottom. The discharge port 146b is closed during the supply of the alkaline aqueous solution 148 and the surplus material 120 and during the alkali treatment step 132, and is opened after the alkali treatment step 132. The alkaline aqueous solution 148 used in the alkali treatment step 132 is discharged as waste liquid 151 from the discharge port 146b. The discharge port 146b is provided with a filter 146c that suppresses the discharge of the crude saponification material 136.

  The cleaning unit 41 of the hard coat removing device 141 is configured in the same manner as the alkali processing unit 142. The cleaning unit 41 preferably includes a container 56 and a temperature controller 57, and further includes a stirrer 60.

  The container 56 is configured in the same manner as the container 146, and a supply port 56 a through which the water 58 and the crude saponified material 136 generated in the alkali treatment step 132 are guided is formed in the upper part, for example. The container 56 stores water 58 and is supplied with the crude saponification material 136. In the water washing step 137 in the container 56, it is preferable that the crude saponification material 136 is brought into contact with the water 58 so as to be immersed therein. The crude saponification material 136 is cleaned with water 58 inside the container 56. In this water washing step 137, the temperature controller 57 controls the temperature inside the container 56, thereby controlling the temperature of the water 58 in the container 56 and the crude saponified material 136. As the water 58, for example, well water can be used.

  The stirrer 60 is for stirring the mixture of the water 58 and the crude saponification material 136. The stirrer 60 is configured similarly to the stirrer 150, and includes a stirring blade 60a, a rotating shaft 60b, and a controller 60c. By rotating the stirring blade 60a integrally with the rotating shaft 60b, the hard coat 121 in which the mixture of the water 58 and the crude saponified material 136 is stirred and decomposed or dissolved is more reliably and efficiently peeled off from the saponified material 138.

  The container 56 is formed with a freely openable / closable discharge port 56b for discharging the water 58 and the decomposed or dissolved hard coat 121 to the outside, for example, at the bottom. The discharge port 56 b is closed while the water 58 and the crude saponified material 136 are supplied to the container 56, and during the water washing step 137, and is open during the dehydration step 32. The water 58 used in the water washing step 31 is discharged as waste liquid 61 from the discharge port 56b. As the water 58 is discharged, the hard coat 121 that has been decomposed or dissolved is discharged. The discharge port 56b is provided with a filter 56c that prevents the wet saponification material 138 from being discharged. The wet saponification material 138 obtained by the water washing step 31 remains in the container 56 without being discharged to the outside by the filter 56c.

  In this embodiment, the alkali treatment unit 142 is used for the alkali treatment step 132, and the cleaning unit 41 of the hard coat removing device 141 is used for the saponification material washing step 133. However, the hard coat removing step 131 is not limited to this mode. For example, one apparatus having the same configuration as the alkali treatment unit 142 may be used for both the alkali treatment step 132 and the saponification material cleaning step 133.

  The saponified layer removing device 38 will be described with reference to FIG. The oxygen treatment unit 39 has the same configuration as the alkali treatment unit 142 and includes a container 46 and a temperature controller 47.

  In the container 46, for example, a supply port 46a through which the saponification material 138 and the cellulase aqueous solution 48 are guided is formed in the upper part. The container 46 stores the cellulase aqueous solution 48 and is supplied with the saponification material 138. The cellulase aqueous solution 48 and the saponification material 138 are in contact with each other inside the container 46. In the container 46, the saponification material 138 is preferably in contact with the cellulase aqueous solution 48 so as to be immersed therein. When a cellulase suspension is used instead of the cellulase aqueous solution 48, the cellulase suspension is stored in the container 46.

  The temperature controller 47 controls the temperature inside the container 46, and thereby controls the temperature of the cellulase aqueous solution 48 and the saponification material 138 in the container 46.

  The enzyme processing unit 39 preferably includes a stirrer 50 for stirring the mixture of the cellulase aqueous solution 48 and the saponification material 138. The stirrer 50 has the same configuration as the stirrer 150, and the mixture of the cellulase aqueous solution 48 and the saponification material 138 is stirred by the rotation of the stirring blade 50a.

  The container 46 has an openable / closable discharge port 46b for discharging the cellulase aqueous solution 48 to the outside, for example, at the bottom. The discharge port 46b is closed during the supply of the cellulase aqueous solution 48 and the saponification material 138 and during the enzyme treatment step 25, and is opened after the enzyme treatment step 25. The cellulase aqueous solution 48 used in the enzyme treatment step 25 is discharged as a waste liquid 51 from the discharge port 46b. The discharge port 46b is provided with a filter 46c for suppressing discharge of the crude cellulose ester material 28.

  The cellulase aqueous solution 48 is for decomposing a saponification layer 155 described later, and is an aqueous solution in which cellulase is dissolved in water. The cellulase of the cellulase aqueous solution 48 is an enzyme group including at least three kinds of enzymes, and the three kinds of enzymes are cellobiohydrolase (CBH), endoglucanase (EG), and β-glucosidase (BGL). is there. When the cellulase aqueous solution 48 comes into contact with the saponification layer 155, the above three kinds of enzymes cooperate to decompose the saponification layer 155. CBH decomposes the crystalline portion of the molecules constituting the saponified layer 155 from the end. The EG randomly decomposes the amorphous part of the molecules constituting the saponified layer 155. BGL degrades the β-binding site of the cellobiose structure.

  The mass of CBH is within the range of 87 mass% to 93 mass% of the mass of cellulase, and the sum of the mass of EG and BGL with respect to the mass of CBH, that is, {(mass of EG) + (mass of BGL)} / (The mass of CBH) is preferably 0.04 or more and 0.15 or less. Thereby, the saponification layer 155 is decomposed more reliably and more efficiently.

  The cellulase preferably contains an enzyme group whose origin bacteria (producing bacteria) are Trichoderma reesei and an enzyme group that belongs to the genus Acremonium. That is, the cellulase is preferably a mixture of an enzyme group derived from Trichoderma reesei and an enzyme group derived from the genus Acremonium. The origin of type A to F cellulases is Trichoderma reesei, and the origin of type G cellulases is the genus Acremonium.

  As the cellulase containing the above three enzymes, type A to type H in the “cellulase” column of Table 1 are more preferred. In addition, each cellulase aqueous solution 48 including cellulase type A to type H is also referred to as type A to type H in the following description as in the “type of cellulase aqueous solution 48” column of Table 1 below.

Since the type H cellulase in Table 1 is a mixture of a type A cellulase and a type G cellulase, it is described as “mixture” in the “trade name” column. Both type A and type G cellulases are in circulation as aqueous solutions, and type H cellulases may have a mass ratio (type A: type G) in the aqueous solution range of 2: 3 to 9: 1. More preferred.

  In addition, since each type B cellulase originates from the genus Acremonium and the type A cellulase originates from Trichoderma reesei, the type H cellulase is derived from the Acremonium genus and Trichoderma reesei. It is a mixture with cellulase.

  The cellulase mass in the cellulase aqueous solution 48 is preferably 0.1% or more with respect to the mass of the saponification material 138. That is, when the mass of the cellulase is M1 and the mass of the saponification material 138 is M2, (M1 / M2) × 100 is preferably 0.1% or more. Thereby, the saponification layer 155 is decomposed more reliably and more efficiently. The mass of cellulase in the cellulase aqueous solution 48 is more preferably in the range of 0.1% or more and 20% or less, and in the range of 0.3% or more and 15% or less with respect to the mass of the saponification material 138. More preferably, it is in a range of 0.5% to 12% (for example, 7.2%).

  It is preferable that the cellulase aqueous solution 48 does not contain other degrading enzymes (for example, protease, amylase, lipase) different from cellulase.

  When the cellulase contains the above three enzymes, the cellulase aqueous solution 48 preferably has a hydrogen ion index (pH) in the range of 3.0 or more and 7.0 or less. Thereby, the saponification layer 155 is decomposed more effectively and efficiently. The pH of the cellulase aqueous solution 48 is more preferably in the range of 3.5 or more and 6.5 or less, and further preferably in the range of 4.0 or more and 6.0 or less (for example, 4.5).

  The cellulase aqueous solution 48 is a mixture of acetic acid and sodium acetate. By adjusting the amount of this liquid, the pH of the cellulase aqueous solution 48 is adjusted.

  When the cellulase contains the above three kinds of enzymes, the temperature of the cellulase aqueous solution 48 in the enzyme treatment step 25 is preferably adjusted within the range of 40 ° C. or more and 70 ° C. or less. Thereby, the saponification layer 155 is decomposed more effectively and efficiently. Therefore, the temperature of the cellulase aqueous solution 48 while in contact with the saponified layer 155 is preferably maintained within the above temperature range. The temperature of the cellulase aqueous solution 48 is more preferably within a range of 45 ° C. or higher and 65 ° C. or lower, and further preferably within a range of 50 ° C. or higher and 60 ° C. or lower (eg, 55 ° C.).

  The saponification layer removing device 38 includes a cleaning unit 41 having the same configuration as the cleaning unit 41 of the hard coat removing device 141. That is, the collection facility 90 includes two cleaning units 41. The cleaning unit 41 of the saponified layer removing apparatus 38 includes a container 56 and a temperature controller 57, and preferably a stirrer 60.

  The supply port 56 a of the container 56 of the cleaning unit 41 provided in the saponified layer removing device 38 guides the water 58 and the crude cellulose ester material 28 obtained in the enzyme treatment step 25 into the container 56. In the container 56, it is preferable to contact so that the crude cellulose-ester material 28 may be immersed in the water 58. FIG. The crude cellulose ester material 28 is cleaned with water 58 inside the container 56. In the water washing step 31, the temperature controller 57 controls the temperature inside the container 56, thereby controlling the temperature of the water 58 and the crude cellulose ester material 28 in the container 56. The stirrer 60 stirs the mixture of the water 58 and the crude cellulose ester material 28.

  The openable / closable outlet 56 b of the container 56 is closed while the water 58 and the crude cellulose ester material 28 are supplied to the container 56 and during the water washing step 31, and is opened during the dehydration step 32. . The water 58 used in the water washing step 31 is discharged as waste liquid 61 from the discharge port 56b. As the water 58 is discharged, the decomposed saponified layer 155 is discharged. The filter 56c in the discharge port 56b suppresses the discharge of the wet cellulose ester material 33.

  In this embodiment, the enzyme treatment unit 39 is used for the enzyme treatment step 25, and the washing unit 41 of the saponification layer removing apparatus 38 is used for the CE material washing step 27. However, the saponified layer removing step 21 is not limited to this mode. For example, a single device configured similarly to the enzyme processing unit 39 may be used for both the enzyme processing step 25 and the CE material cleaning step 27. In addition, one apparatus configured in the same manner as the alkali treatment unit 142 may be used for all the steps of the alkali treatment step 132, the saponification material washing step 133, the enzyme treatment step 25, and the CE material washing step 27.

  The operation of the above configuration will be described. When the surplus material 120 is guided to the crusher 37, it is cut into smaller sizes by a cutting machine. The surplus material 120 having a small size is sent to the container 146 of the alkali treatment unit 142 via a pipe connecting the crusher 37 and the alkali treatment unit 142 by a delivery machine. When there is no crushing step 26, the surplus material 120 is guided to the container 146 of the alkali processing unit 142 without passing through the crusher 37.

  An aqueous alkali solution 148 is guided to the container 146, and the temperature of the aqueous alkali solution 148 is controlled by the temperature controller 147 so as to be within the above-described temperature range, and is stirred by the stirrer 150. The surplus material 120 is guided to the container 146 and supplied to the alkali treatment step 132, and is immersed, for example, in contact with the stored alkaline aqueous solution 148. Thereby, the hard coat 121 having a crosslinked molecular structure is decomposed or dissolved. During the alkali treatment step 132, the temperature of the alkaline aqueous solution 148 is maintained within the above-described range, and the mixture of the alkaline aqueous solution 148 and the surplus material 120 is stirred by the stirrer 150. By this stirring, decomposition and dissolution of the hard coat 121 are further promoted.

  By the alkali treatment process 132, the outer periphery of the cellulose ester layer 11 of the surplus material 120 is saponified to become a saponified material 138 (see FIG. 8). A part of the hard coat 121 decomposed or dissolved is detached from the saponification material 138.

  The time of the alkali treatment step 132, that is, the contact time between the alkaline aqueous solution 148 and the surplus material 120 is preferably in the range of 60 minutes or more and 180 minutes or less, and is preferably in the range of 80 minutes or more and 120 minutes or less. More preferred.

  After the alkali treatment step 132, the aqueous alkali solution 148 is discharged from the container 146 as the waste liquid 151 from the discharge port 146b. Small pieces of the hard coat 121 that are detached and float in the alkaline aqueous solution 148 are discharged together with the alkaline aqueous solution 148. On the other hand, the crude saponified material 136 remains in the container 146 without being discharged by the filter 146c provided in the discharge port 146b.

  The water 58 and the crude saponified material 136 are stirred by the stirrer 60 when guided to the container 56 of the cleaning unit 41 in the hard coat removing device 141. The crude saponification material 136 is in contact with water 58, for example. By this water washing step 137, the hard coat 121 remaining on the saponification material 138 is detached from the saponification material 138 and removed. By the stirring by the stirrer 60, the hard coat 121 is detached from the saponification material 138 more effectively and efficiently.

  In the dehydration process 32 after the water washing process 137, the water 58 is discharged as the waste liquid 152 from the discharge port 56b. Small pieces of the hard coat 121 that are detached and floating in the water 58 are discharged together with the water 58. When the hard coat 121 remains in the container 56, the water washing process 137 and the dehydration process 32 are repeated. Through such a saponification material cleaning step 133, the saponification material 138 is obtained in a wet state.

  The container 46 of the enzyme treatment unit 39 is guided with a cellulase aqueous solution 48 prepared in advance according to a predetermined formulation. The temperature of the cellulase aqueous solution 48 is controlled by a temperature controller 47 so as to be within a predetermined range, and a stirrer 50 is used. Is stirred. When the saponification material 138 is guided to the container 46, the saponification material 138 comes into contact with, for example, the stored cellulase aqueous solution 48. Thereby, the saponification layer 155 is decomposed, and a part of the decomposition is detached from the cellulose ester layer 11. During the enzyme treatment step 25, the temperature of the cellulase aqueous solution 48 is maintained within a predetermined temperature range, and the mixture of the cellulase aqueous solution 48 and the saponification material 138 is stirred by the stirrer 50. By stirring, the saponified layer 155 is decomposed more effectively and efficiently.

  The time of the enzyme treatment step 25, that is, the contact time between the cellulase aqueous solution 48 and the saponification material 138 is preferably within the range of 20 minutes to 180 minutes, and preferably within the range of 60 minutes to 180 minutes. More preferably, it is in the range of 90 minutes or more and 180 minutes or less.

  By using the cellulase aqueous solution 48 in which the cellulase derived from Trichoderma reesei and the cellulase derived from the genus Acremonium are used, the time required for the saponification material 155 to decompose is shortened, and the enzyme treatment step 25 is performed. Proceed more efficiently. For example, by using the type H cellulase, the enzymatic treatment proceeds more rapidly than when the type A and type G cellulases are used alone, and the crude cellulose ester material 28 is generated more efficiently.

  The cellulase aqueous solution 48 used in the enzyme treatment step 25 is discharged as the waste liquid 51 from the discharge port 46 b of the container 46. Small pieces of the saponified layer 155 that have been detached and floated in the cellulase aqueous solution 48 are discharged together with the cellulase aqueous solution 48. On the other hand, the crude cellulose ester material 28 remains in the container 46 without being discharged by the filter 46c provided in the discharge port 46b.

  The crude cellulose ester material 28 and the water 58 are guided to the container 56 of the cleaning unit 41 of the saponification layer removing device 38 and supplied to the water washing step 31, and the crude cellulose ester material 28 is in contact with the water 58, for example. As a result, the saponified layer 155 is detached and removed. Further, by the stirring by the stirrer 60, the decomposed saponified layer 155 is more reliably and more efficiently separated from the cellulose ester layer 11.

  In the dehydration process 32 after the water washing process 31, the water 58 is discharged as the waste liquid 61 from the discharge port 56b. Small pieces of the saponified layer 155 that have been detached and floated in the water 58 are discharged together with the water 58. If the saponified layer 155 that has undergone the dehydration process 32 remains inside the container 56, the water washing process 31 and the dehydration process 32 are repeated. The wet cellulose ester material 33 is obtained by such a CE material cleaning step 27.

  The wet cellulose ester material 33 is guided to a housing part (not shown) of the drying unit 42 and supplied to the drying step 22 and is dried by supplying a dry gas from a blower part (not shown). Further, the evaporated water 58 is discharged out of the accommodating portion by a discharge mechanism (not shown), and drying of the wet cellulose ester material 33 is promoted. By such a drying step 22, a cellulose ester material 34 is obtained. Note that the decomposition of the saponified layer 155 by cellulase can be easily terminated by the start of contact of the water 58 with the crude cellulose ester material 28. Therefore, according to this method, the cellulose ester material 34 is recovered in a high yield by bringing the water 58 into contact with the crude cellulose ester material 28 so that the enzymatic treatment is completed when the cellulose ester layer 11 starts to be decomposed.

  The saponification material 138 will be described in detail with reference to FIG. By the alkali treatment step 132, the outer peripheral portion of the cellulose ester layer 11 of the surplus material 120 is saponified as described above. The saponification material 138 obtained in this way includes the cellulose swell layer 11 and the saponification layer 155. The saponified layer 155 overlaps the outer periphery of the cellulose ester layer 11 so as to cover the cellulose ester layer 11. Since the saponification layer 155 is formed by saponifying a part of the cellulose ester layer 11 before the alkali treatment step 132, the thickness T138 of the saponification material 138 is the thickness T11 of the cellulose ester layer 11 before the alkali treatment step 132. Is almost equivalent. When the acyl group substitution degree of the cellulose ester constituting the cellulose ester layer 11 is 2.86, a saponified layer 155 having an acyl group substitution degree in the range of 0.5 to 2.0 is generated.

  In FIG. 8, the boundary between the cellulose ester layer 11 and the saponified layer 155 is illustrated for convenience of explanation, but this boundary is not necessarily clear and may not be visually recognized, for example. In addition, in FIG. 8, the arrow T is attached | subjected to the thickness direction.

  In addition, even if the surplus material 120 as an object for recovering the cellulose ester is further provided with another functional layer on the surface opposite to the one surface in close contact with the cellulose ester layer 11 of the hard coat 121. Good. Another functional layer is, for example, an antireflection layer. Even in such a case, the antireflection layer is removed together with the hard coat 121 according to the above embodiment, and the cellulose ester material 34 is recovered.

  Hereinafter, the antireflection layer when the surplus material 120 further includes an antireflection layer will be described in detail.

(Antireflection layer)
The antireflection layer is composed of at least one layer composed of a polymer binder, a polymerization initiator, a dispersant, and the like. Therefore, the antireflection layer may have a multilayer structure of two or more layers. Examples of the layer constituting the antireflection layer include a light diffusion layer, a low reflectance layer, a medium refractive index layer, a high refractive index layer, an optical compensation layer, and an antiglare property-imparting layer. The layers constituting the antireflection layer may be the same type or layers having different compositions, and a desired antireflection layer may be formed by appropriately selecting from the above. However, in order to obtain an excellent antireflection effect, it is preferable that an antiglare property-imparting layer is included as a layer.

  The binder used for the antireflection layer is preferably a polymer having a saturated hydrocarbon chain or a polyether chain as the main chain. By using a polymer as a binder by appropriately selecting the structure of the monomer constituting such a polymer, the presence or absence of an aromatic ring, the presence or absence of an atom such as a halogen atom, a sulfur atom, a phosphorus atom or a nitrogen atom. The refractive index of the layer to be formed can be suitably adjusted.

  It is preferable that a plurality of light-transmitting fine particles are added to the antireflection layer. Hereinafter, fine particles that do not absorb in the visible light region are referred to as translucent fine particles. When a plurality of such translucent fine particles are added to the antireflection layer, the refractive index of the layer can be easily adjusted by the action of the fine particles, and the translucent fine particles transmit light. The anti-glare property can be suitably adjusted. The translucent particles are specifically described in [0044] of JP-A No. 2003-302506, and can be applied to the present invention. In addition, it is preferable that the light-transmitting fine particles are appropriately selected in consideration of the refractive index difference according to the refractive index of the layer to be formed.

The translucent fine particles are preferably at least one metal oxide of titanium, zirconium, aluminum, indium, zinc, tin, and antimony. The average particle size is preferably 0.2 μm or less, more preferably 0.1 μm or less, and particularly preferably 0.06 μm or less. Examples of the metal oxides, _{e.g., TiO 2, ZrO 2, Al} 2 O 3, In 2 O 3, ZnO, SnO 2, Sb 2 O 3, ITO, SiO 2 , and the like. Among these, TiO ₂ and ZrO ₂ are preferable in terms of increasing the refractive index. In addition, it is preferable to treat the surface of each fine particle with a silane coupling agent or a titanium coupling agent because dispersibility and compatibility with the binder can be improved. The addition amount of the fine particles is preferably 10 to 90%, more preferably 20 to 80%, and particularly preferably 30 to 75% with respect to the total mass of the layer to be added.

Of the translucent fine particles, as fine particles used for the purpose of imparting antiglare properties, mat particles having a particle size larger than the filler particles and an average particle size of about 1 to 10 μm can be preferably used. Examples of the mat particles include inorganic compound particles such as silica particles and TiO ₂ particles, and organic compound particles such as acrylic particles, cross-linked acrylic particles, polystyrene particles, cross-linked styrene particles, melamine particles, and benzoguanamine particles. Among them, it is preferable to use crosslinked styrene particles, crosslinked acrylic particles, and silica particles because high antiglare properties can be expressed. The shape of the mat particle is not particularly limited, regardless of whether it is a true sphere or an indefinite shape. Two or more kinds of mat particles having different particle sizes and shapes can be used in combination. In order to form the antiglare layer, the content of the matte particles is preferably a 10~2000mg to layer 1 m ² around to form. More preferably, it is 100-1400 mg.

  The mat particles are preferably uniformly dispersed in the layer. Moreover, it is preferable that the particle diameter of each particle is substantially the same. For example, when particles larger than the average particle diameter by 20% or more are used as coarse particles, the ratio of coarse particles contained in all particles is preferably 1% or less, more preferably 0.1% or less. . Therefore, it is preferable to use mat particles having substantially the same particle diameter and subjected to as many strong classifications as possible for the purpose of uniform dispersion in the layer. Note that the fine particles described above have a particle size sufficiently smaller than the wavelength of light, and thus light scattering does not occur.

  The cellulose ester material 34 collected by the above method is used as a polymer component for producing a film by a solution casting method. As shown in FIG. 9, a solution casting apparatus 161 for producing a film 160 by a solution casting method includes, for example, a casting device 164, a tenter 165, a drying device 166, and a winding device 167 upstream. Prepare in order from the side.

  The casting apparatus 164 is for forming the wet film 172 from the dope 171. The casting apparatus 164 includes a belt 173 as a support, rollers 176 and 177, and a casting die 178. The belt 173 is formed in an annular shape and is wound around rollers 176 and 177. At least one of the rollers 176 and 177 is rotated in the circumferential direction by a drive mechanism (not shown), and this rotation causes the belt 173 to travel in the longitudinal direction and circulate. The casting die 178 is disposed on the belt 173. The casting die 178 flows out the guided dope 171.

  As a support, a drum (not shown) may be used instead of the belt 173. A roller 181 is disposed in the vicinity of the belt 173 and is rotated in the circumferential direction by a drive mechanism (not shown). A wet film 172 is wound.

  A tenter 165 disposed downstream of the roller 181 is for applying tension in the width direction while drying the wet film 172. The tenter 165 includes, for example, a plurality of clips (not shown) that grip each side end of the wet film 172, a chain (not shown) to which the clips are attached, and a rail (not shown) that constitutes a travel path of the chain. And a blower (not shown).

  The plurality of clips are attached so as to be aligned in the longitudinal direction of the chain, and each clip is transported on the travel path of the chain as the chain travels on the rail. The tension in the width direction applied to the wet film 172 can be changed by changing the distance between the rails arranged on each side end of the wet film 172. The blower is provided on the conveyance path of the wet film 172 and flows out the dried gas.

  The drying device 166 is for drying the wet film 172 into the film 160, and includes a plurality of rollers 166a for supporting the wet film 172 and a plurality of blowers (not shown). The winding device 167 is for winding the long film 160 in a roll shape. A winding core is set and the winding core is rotated in the circumferential direction.

  The operation of the above configuration will be described. The dope 171 is formed by dissolving the cellulose ester material 34 in the solvent 183. In addition to the cellulose ester material 34, a cellulose ester material 184 made of cellulose ester newly produced by esterifying cellulose may be used. Moreover, you may add additives, such as a plasticizer and a ultraviolet absorber, to the dope 171. By continuously flowing out the dope 171 from the casting die 178 to the running belt 173, the casting film 182 is continuously formed on the belt 173. The cast film 182 has a self-supporting property by being dried by a drying means (not shown) such as a blower or cooled or heated while being conveyed by the running of the belt 173.

  When the wet film 172 is wound around the rotating roller 181, the casting film 182 is peeled off. The wet film 172 is allowed to dry while being given a predetermined tension in the width direction by the tenter 165. By adjusting the tension in the width direction with respect to the wet film 172 being dried, the width of the wet film 172 is expanded, decreased, or kept constant. The wet film 172 guided to the drying device 166 is dried while being transported to form a film 160. The film 160 guided to the winding device 167 is wound on the winding core by the rotation of the winding core.

  The above embodiment is a case where the object for recovering the cellulose ester is composed only of the cellulose ester layer 11 and the hard coat 121, but the present invention is not limited to this embodiment. For example, the target for recovering the cellulose ester is such that an optically anisotropic portion (not shown) is formed on the surface opposite to the surface on which the hard coat 121 of the cellulose ester layer 11 is formed. Also good. As is well known, the optically anisotropic portion is usually composed of a liquid crystal layer and an alignment layer for aligning the liquid crystal compound of the liquid crystal layer. The alignment layer is disposed in close contact with the cellulose ester layer 11, and the liquid crystal layer is disposed on the alignment layer. The alignment layer is made of, for example, polyvinyl alcohol (PVA) or modified PVA, and has a thickness in the range of approximately 0.2 μm to 1.0 μm. The liquid crystal layer is formed of, for example, a liquid crystal discotic compound or a rod-like liquid crystal compound, and has a thickness in the range of approximately 0.5 μm to 3.0 μm.

  The method of recovering cellulose ester from the cellulose ester layer 11 of a material in which the hard coat 121 is disposed on one surface of the cellulose ester layer 11 and the optically anisotropic portion is disposed on the other surface, An optically anisotropic part removing step to be removed is provided before the saponified layer removing step 21. In this method, for example, the optically anisotropic portion is removed between the crushing step 26 and the hard coat removing step 131 in the recovery flow 130 of FIG. 4 or between the hard coat removing step 131 and the saponified layer removing step 21. Process. As described above, the hard coat 121 may be removed after removing the optically anisotropic portion, or the optically anisotropic portion may be removed after removing the hard coat 121.

  The optically anisotropic part removing step includes a hot water treatment step and may further include a cleaning step. In the hydrothermal treatment step, the optically anisotropic portion is brought into contact with liquid water whose temperature is adjusted within a predetermined range, for example, so that the alignment layer of the optically anisotropic portion is decomposed and dissolved. It is a process to be performed. The temperature of water shall be 90 degreeC or more. By this hydrothermal treatment process, the optically anisotropic part is detached from the cellulose ester layer 11. When at least a part of the small pieces of the optically anisotropic portion once detached adheres to the cellulose ester layer 11, the attached optically anisotropic portion is removed by subjecting it to a washing step. The washing step is a step of washing with water. The hot water treatment and the cleaning can be performed by an apparatus having the same configuration as the alkali processing unit 142 and the cleaning unit 41.

  Next, the present invention will be described in more detail with reference to examples. Moreover, the following comparative example was implemented as a comparative experiment with respect to the present invention. Details will be described in the first embodiment, and the description of the same processing and conditions as in the first embodiment will be omitted for the second and comparative examples.

  As shown in FIGS. 1 and 2, a rectangular hard coat sheet 71 having a predetermined size was cut out from the hard coat web 70. About the surplus material 120, the cellulose ester was collect | recovered as the cellulose-ester material 34 with the collection | recovery flow 130 shown in FIG. The collection of the cellulose ester material 34 was performed by a collection facility 90 shown in FIG.

  50 g of surplus material 120 was supplied to the crusher 37 and crushed by the crusher 37. In the crushing step 26, the surplus material 120 is cut to become finer by a cutter of the crusher 37, and is cut into a material piece (chip) having a size of approximately 0.5 cm × 0.5 cm to 1.0 cm × 1.0 cm. did. The surplus material 120 made into this piece of material was blown to the hard coat removing device 141 by the delivery device of the crusher 37.

  The alkaline aqueous solution 148 and the surplus material 120 were supplied to the container 146 of the alkali treatment unit 142, and the temperature of the mixture was maintained within a range of 50 ° C. or more and 60 ° C. or less by the temperature controller 147. The alkali of the alkaline aqueous solution 148 is NaOH, the alkali concentration is 7%, and the hydrogen ion exponent pH of the alkaline aqueous solution 148 is 12.5. During the alkali treatment step 132, the inside of the container 146 was continuously stirred by the stirrer 150. The time for the alkali treatment step 132 was 100 minutes.

  The crude saponified material 136 obtained in the alkali treatment step 132 was guided to the cleaning unit 41 of the hard coat removing device 141 in order to be used for the saponified material cleaning step 133. The number of times the saponification material cleaning step 133 is performed is one. The temperature of the water 58 was 20 ° C. During the saponification material cleaning step 133, the inside of the container 56 was continuously stirred by the stirrer 60.

  The wet saponified material 138 obtained through one dehydration step 32 in the hard coat removing step 131 was guided to the saponified layer removing device 38 and subjected to the saponified layer removing step 21. As shown in Table 2, a plurality of experiments were performed in which the conditions in the saponified layer removing step 21 were different from each other. The time for the enzyme treatment step 25 was 180 minutes in all experiments. The cellulase aqueous solution 48 was adjusted so that the hydrogen ion exponent pH became a value shown in the column “Liquid pH” in Table 2 by mixing a solution obtained by adding sodium acetate to acetic acid. In the enzyme treatment step 25, the saponification material 138 was immersed in the cellulase aqueous solution 48.

  The mass of the cellulase in each cellulase aqueous solution 48 is shown in units of% in the “Concentration” column of Table 2 as a ratio to the mass of the saponification material 138. The temperature of the cellulase aqueous solution 48 in the enzyme treatment step 25 is shown in the unit of ° C. in the “Liquid temperature” column of Table 2.

  The crude cellulose ester material 28 obtained by the enzyme treatment step 25 was guided to the cleaning unit 41 of the saponification layer removing device 38 and supplied to the CE material cleaning step 27. The CE material cleaning step 27 was performed once.

  The wet cellulose ester material 33 obtained by the saponification layer removing step 21 was supplied to a drying unit 42 and dried to obtain a cellulose ester material 34. The mass of the cellulose ester material 34 obtained in each experiment is shown in g in the “cellulose ester material” column of Table 2.

  About the obtained cellulose-ester material 34, the degree of removal of the optically anisotropic part 74 and the saponification layer 155 was evaluated, respectively. The evaluation was performed by the following visual evaluation method. The evaluation results of each experiment are shown in Table 2.

<Visual evaluation method>
15 g of cellulose ester material 34 was dissolved in 85.0 g of a solvent to prepare a dope having a cellulose ester material 34 concentration of 15%. The solvent is a mixture of 78.0 g methylene chloride and 6.8 g methanol. The obtained dope was visually observed to confirm gelled or solid foreign matters. Based on the number of these foreign substances having a diameter of 100 μm or more, the dope was evaluated according to the following criteria. A to C are acceptable levels, and D to E are unacceptable levels.

A: 0 or more and 2 or less B: 3 or more and 5 or less C: 6 or more and 10 or less D: 11 or more and 20 or less E: 21 or more

[Comparative Example 1]
(1) Comparative experiment 1
Similarly to Example 1, 50 g of surplus material 120 was cut with a crusher 37 to obtain a piece of material (chip) having a size of approximately 0.5 cm × 0.5 cm to 1.0 cm × 1.0 cm. The surplus material 120 made into this piece of material was subjected to the following cleaning and polishing step.

  First, the cleaning liquid containing the abrasive and the fine surplus material 120 were placed in a container having the same configuration as the container 46 of the enzyme treatment unit 39 used in Example 1, and the surplus material 120 was immersed in the cleaning liquid. Diatomaceous earth was used as an abrasive. Cellulase aqueous solution is not used. Therefore, “diatomaceous earth treatment” is described in the “cellulase aqueous solution type column” in Table 2. The mass of diatomaceous earth in the cleaning liquid was a percentage shown in the “Concentration” column of Table 2 with respect to the mass of the surplus material 120. The temperature of the cleaning liquid is shown in the unit of ° C. in the “Liquid temperature” column of Table 2, and the hydrogen ion index of the cleaning liquid is shown in the “Liquid pH” column of Table 2.

  The mass of the obtained cellulose ester material is shown in the unit of g in the “cellulose ester material” column of Table 2. Moreover, it evaluated similarly to Example 1 about the obtained cellulose-ester material. The evaluation results are shown in Table 2.

(2) Comparative experiment 2
Instead of the cellulase aqueous solution 48 of Example 1, water was used. Therefore, “cellulase aqueous solution” column in Table 2 is described as “no cellulase added” and “concentration” column is described as “0.0”. The water was mixed with a solution obtained by adding sodium acetate to acetic acid, and the pH of the water was adjusted to the value shown in the “Liquid pH” column of Table 2 by this mixing. Other conditions are the same as those in the first embodiment.

  The time of the enzyme treatment step 25 of Example 1 was changed to 30 minutes, and this was designated as Experiment 1. Further, Experiments 2 to 6 were conducted by replacing the cellulase aqueous solution 48 in Example 1 with those shown in the column “Cellulase aqueous solution” in Table 3. In addition, the time of the enzyme treatment process 25 of Experiments 2-6 was all 30 minutes.

  The mass of the obtained cellulose ester material 34 is shown in units of g in the “cellulose ester material” column of Table 3. Moreover, about the obtained cellulose-ester material 34, the degree of removal with the hard-coat 121 and the saponification layer 155 was evaluated, respectively. The evaluation was performed by the visual evaluation method described above. Each evaluation result is shown in Table 3.

  Instead of the surplus material 120 of Example 1, a surplus material (not shown) provided with a hard coat 121 on one side of the cellulose ester layer 11 and an antireflection layer on the other side was used. The antireflection layer has a three-layer structure, and is formed by laminating a string-proofing layer, a high refractive index layer, and a low refractive index layer in this order from the cellulose ester layer 11 side. This surplus material was used for the alkali treatment process 132 and the saponification material washing | cleaning process 133, and the saponification material 138 was obtained. The time for the alkali treatment step 132 was 90 minutes, and the temperature of the mixture of the alkaline aqueous solution 148 and the surplus material in the alkaline aqueous solution 148 was 95 ° C. Other conditions for the alkali treatment step 132 and the saponification material cleaning step 133 are the same as those in the first embodiment. From the obtained saponification material 138, the cellulose ester material 34 was each collect | recovered in the following experiments 1-3.

  In Experiments 1 to 3, 45 g of saponification material 138 was supplied to the enzyme treatment step 25, and then the cellulose ester material 34 was obtained through the CE material washing step 27 and the drying step 22. The cellulase aqueous solution 48 used was type A in experiment 1, type G in experiment 2, and type H in experiment 3. In Experiment 1, 2 g of type A cellulase (Entilon MIT conc) was used, in Experiment 2, 2 g of type G cellulase (Entilon BAS) was used, and in Experiment 3, a mixture of 1 g of Entilon MIT conc and 1 g of Enthrone BAS was typed. H cellulase was used. The enzyme treatment step 25 is performed under the conditions that the hydrogen ion exponent pH is 4.5, the temperature of the cellulase aqueous solution 48 is 55 ° C., and the enzyme treatment time is 1 hour. The total mass of the cellulase aqueous solution 48 and 45 g of the saponification material 138 was 150 g.

  Each cellulose ester material 34 obtained in Experiments 1 to 3 was dissolved in 78.0 g of methylene chloride, and the above-described visual evaluation method, that is, the obtained liquid was visually observed and evaluated according to criteria A to E. The result of Experiment 1 was A (the number of foreign objects was 2), the result of Experiment 2 was C (the number of foreign objects was 8), and the result of Experiment 3 was A (the number of foreign objects was 0).

DESCRIPTION OF SYMBOLS 11 Cellulose ester layer 38 Saponification layer removal apparatus 39 Enzyme processing unit 41 Washing unit 48 Cellulase aqueous solution 90 Recovery equipment 120 Excess material 138 Saponification material 141 Hard coat removal apparatus 142 Alkali processing unit 148 Alkaline aqueous solution 155 Saponification layer

Claims (9)

The hard coat material comprising a cellulose ester layer and a hard coat disposed on one surface of the cellulose ester layer is brought into contact with an aqueous alkali solution to decompose and dissolve the hard coat and to obtain an outer periphery of the cellulose ester layer. An alkali treatment step of saponifying the part to form a saponified layer;
A first cleaning step of removing the hard coat by washing the hard coat material after the alkali treatment step with water;
An enzyme treatment step of decomposing the saponification layer by bringing the saponification material comprising the cellulose ester layer and the saponification layer into contact with an aqueous solution or suspension containing cellulase after the first washing step;
The saponification material after the enzyme treatment step by washing with water, have a second cleaning step of removing the saponification layer,
The cellulase includes a group of enzymes produced by Trichoderma reesei and a group of enzymes produced by the genus Acremonium . The aqueous solution or suspension containing the cellulase is a mixture of a first aqueous solution containing an enzyme group produced by Trichoderma reesei and a second aqueous solution containing an enzyme group produced by Acremonium.
The method for recovering a cellulose ester according to claim 1, wherein a mass ratio between the first aqueous solution and the second aqueous solution is in a range of 2: 3 to 9: 1. The method for recovering a cellulose ester according to claim 1 or 2, wherein the aqueous solution or suspension containing the cellulase does not contain another degrading enzyme different from the cellulase. The cellulase includes cellobiohydrolase,
The method for recovering a cellulose ester according to any one of claims 1 to 3, wherein a mass of the cellobiohydrolase is in a range of 87 mass% to 93 mass% of a mass of the cellulase. The cellulase includes cellobiohydrolase, endorcanase, and β-glucosidase,
The method for recovering a cellulose ester according to any one of claims 1 to 4, wherein the sum of the masses of endorcanase and β-glucosidase with respect to the mass of cellobiohydrolase is in the range of 0.04 to 0.15. . The method for recovering a cellulose ester according to any one of claims 1 to 5, wherein the time of the enzyme treatment step is within a range of 90 minutes to 180 minutes. The method for recovering a cellulose ester according to any one of claims 1 to 6, wherein a mass of the cellulase is in a range of 0.1% to 20% with respect to a mass of the saponification material. The method for recovering a cellulose ester according to any one of claims 1 to 6, wherein the hydrogen ion exponent pH of the aqueous alkali solution is in the range of 12.0 to 14.0. The cellulose ester recovered by the cellulose ester recovery method according to any one of claims 1 to 8 is used as a polymer component of the dope,
Casting the dope to a support to form a cast film,
A solution casting method, wherein the cast film is peeled off from the support and dried to form a film.

Images