JP2005131801A - Recovery method of polyester resin support - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recovery method of a polyester resin support from a recording material, where a coating film is formed on the support, in such a state that the support can be recycled as a raw material of the support for a recording material by suppressing re-adhesion to the support, thermal fusion at parts in contact with a treating liquid such as an inner wall, a stirring blade, a rotary shaft, or the like of the coating film and sludge, and to facilitate the cleaning of the treatment tank after treatment. <P>SOLUTION: In the recovery method of the polyester resin support for treating the chip-like recording material, wherein at least one coating film is provided on the polyester resin support, with an alkaline treatment liquid in the treatment tank using a stirrer and subsequently recovering the polyester resin support from the alkaline treatment liquid, the treatment of the recording material with the alkaline treatment liquid comprises two stages of first treatment at a temperature of 70-95°C and for a time of 10-120 min and second treatment at a temperature of 1-35°C and for a time of 5-120 min. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a recovery method for recovering a polyester resin support from a recording material having at least one coating film on the polyester resin support.

  Polyester resins such as polyethylene terephthalate and polyethylene naphthalate are used as a support for recording materials such as silver halide photographic light-sensitive materials, heat-developable photographic light-sensitive materials, ink-jet recording materials, and magnetic recording materials because of their excellent characteristics, and liquid crystal displays. It is also widely used in the information recording industry as an optical film used in various display devices of organic EL displays. The case of a photographic photosensitive material as an example of a recording material using a polyester resin support will be schematically described with reference to the drawings.

  FIG. 4 is a schematic sectional view of a photographic light-sensitive material.

  In the figure, 6 indicates a photographic material. Reference numeral 601 denotes a polyester resin support, and reference numerals 602a and 602b denote undercoat layers. Reference numeral 603 denotes a photosensitive layer of a coating film formed on the polyester resin support 601 via the undercoat layer 602a, and 605 denotes a protective layer of the coating film formed on the photosensitive layer 603. Reference numeral 604 denotes a coating layer backing layer formed on the polyester resin support 601 through the undercoat layer 602b. The photosensitive layer 603 may be composed of multiple layers as required, or may not be provided with a protective layer. The photosensitive layer 603, the protective layer 605 and the backing layer are selected and used depending on the type of photographic photosensitive material produced by a natural polymer binder or a synthetic polymer binder. In the present invention, the coating film is a generic name including a photosensitive layer, a protective layer, and a backing layer.

  In recent years, the information recording industry has undergone remarkable development and the number of polyester resin materials used has been rapidly increasing. Along with this, the amount of waste products (for example, production scraps, defective products generated in the product inspection process, etc.) and used products generated in the manufacturing process are increasing.

  In fact, most of these polyester resin wastes are used in landfill or incineration without being effectively used, but in landfill there is no decay, and incineration generates dioxins depending on the incineration conditions. It is also a cause of increasing the global environmental load. Moreover, there is a problem of loss of polyester raw material, which is not preferable from the viewpoint of resource saving.

  In particular, using these polyester resin supports, for recording materials using a synthetic polymer material as a binder for the coating film, it is difficult to recover in a state that can be reused as a polyester resin support, Most of the used products and production scraps were not effectively used, and inevitably, incineration treatment was performed at a high temperature in order to suppress the generation of dioxins. For this reason, the incinerator is quickly damaged due to the high-temperature incineration process, which causes a problem of maintenance costs.

  In order to solve these problems, methods for recovering a polyester resin support from a recording material using the polyester resin support have been studied. For example, a printing plate-making film using a support using polyethylene terephthalate (PET) as a polyester resin with a copolymer such as vinylidene chloride, itaconic acid or acrylic acid as an undercoat layer is cationic in an aqueous solution of an alkali metal salt. A method of recovering PET by heat treatment at 50 to 95 ° C. with a surfactant is known (see, for example, Patent Document 1).

  A polyester resin support having an undercoat layer and a silver halide photographic light-sensitive material using the polyester resin support are crushed into chips, and surfactants (nonionic surfactant, cationic surfactant, anionic surfactant) are added. A method for recovering a polyester-based resin support (hereinafter also simply referred to as a support) is known in combination with heat treatment with an alkaline treatment liquid containing sodium hydroxide or potassium hydroxide at a temperature of 70 to 100 ° C. while stirring. (For example, see Patent Document 2).

  However, in the recovery methods described in Patent Document 1 and Patent Document 2, when a support is recovered from a recording material in which a synthetic polymer binder is used and a coating film is formed on the support, there are the following problems. . 1) A support for recording materials, in which the peeled coating film and the support on which sludge generated by the treatment with the alkaline processing liquid is reattached, the support in which the coating film is not peeled off, the peeled coating film, and the like are mixed. It is insufficient in purity to be reused as a raw material. 2) The peeled coating film and sludge are reattached to places that come into contact with the processing liquid such as the inner wall of the processing tank, the stirring blade, and the rotating shaft, and it takes time to clean the processing tank after processing, reducing work efficiency. Yes.

  In particular, when reusing as a raw material for a support for recording material, the following items are listed as required items. 1) There is no contamination with impurities that adversely affect performance (for example, in the case of photographic materials, fog, sensitivity abnormalities such as sensitization / desensitization, etc.) 2) Physical properties (color tone, molecular weight distribution, etc.) are changed 3) The absence of foreign matter that adversely affects the image when taken, and the like.

From these situations, a support for a recording material (especially for a photographic light sensitive material having a high purity requirement) from a recording material in which a coating film is formed using a natural polymer binder and a synthetic polymer binder for the support. Development of a method for recovering a support in a state where it can be reused as a raw material and a method for recovering a support that facilitates cleaning of a treated tank after processing is desired.
Japanese Patent Laid-Open No. 11-302580 JP-A-8-146560

  The present invention has been made in view of the above circumstances, and the object thereof is a coating film peeled from a recording material in which a coating film is formed using a natural polymer binder and a synthetic polymer binder on a support. In addition, it can be reused as a raw material for the support for recording materials by suppressing the reattachment of sludge to the support, heat treatment between the inner wall of the processing tank, the stirring blade, the rotating shaft, etc. It is an object of the present invention to provide a method for recovering a support that is easy to recover the support and clean the treatment tank after the treatment.

The above object of the present invention has been achieved by the following constitution.
(Claim 1)
A chip-shaped recording material having at least one coating film on a polyester resin support is treated with an alkaline treatment liquid in a treatment tank using a stirrer, and the polyester resin support is separated from the alkaline treatment liquid. Then, in the polyester resin support recovery method of recovering the polyester resin support,
The treatment with the alkaline treatment liquid is performed in two stages of a first treatment at a temperature of 70 to 95 ° C. and a time of 10 to 120 min and a second treatment at a temperature of 1 to 35 ° C. and a time of 5 to 120 min. Polyester-based resin support recovery method.
(Claim 2)
The polyester resin support recovery method according to claim 1, wherein an inner surface of the treatment tank is covered with a heat-resistant release film.
(Claim 3)
The method for recovering a polyester resin support according to claim 1 or 2, wherein the coating film uses a natural polymer binder or a synthetic polymer binder.
(Claim 4)
The polyester-based resin support recovery method according to any one of claims 1 to 3, wherein the chip-shaped recording material is an indeterminate shape having an outer size of 0.1 to 100 mm.

  As a result of intensive studies to achieve the above-mentioned problems, the inventors have made a recording material in which a coating film is formed using a natural polymer binder or a synthetic polymer binder on a support, and the support is made into a chip. In the case of recovery, impurities are mixed in depending on the conditions of the film removal treatment with an alkali treatment liquid, particularly the treatment temperature and treatment time, and it is difficult to reuse the raw material for the recording material support and the inner wall of the treatment tank. It was found that the agitation blade, the coating film peeled off on the rotating shaft, and the generated sludge adhered to each other, and it took time for cleaning after the treatment, thereby reducing the work efficiency.

  It was presumed that the cause of the contamination of impurities and the contamination of the treatment tank in contact with the treatment liquid were caused by the following phenomenon. 1) When the peeled coating film is placed under a high temperature condition for a long time, the surface increases in viscosity, and at the same time, the elasticity is lost and it adheres to the support and the portion in contact with the treatment liquid in the treatment tank. 2) When the generated sludge is placed under high temperature conditions for a long time, the viscosity of the surface increases, and the sludge adheres to the support and the portion in contact with the treatment liquid in the treatment tank. 3) If the coating film, support and sludge are separated while the treatment liquid is at a high temperature, the coating film and sludge adhering to the support will act as an adhesive to further adhere the support firmly, and separation will not occur. It becomes possible. In addition, the coating film and sludge adhering to the portion in contact with the processing liquid are more firmly bonded and difficult to separate because the processing liquid disappears from the contact interface.

  When performing film removal treatment with an alkali treatment liquid on these, the film is treated at a high temperature in order to promote peeling of the coating film, and the attached coating film and sludge are removed again in the presence of the treatment liquid, and the treatment tank It has been found that it is effective to reduce the surface energy of the portions that come into contact with the processing liquid such as the inner wall, the stirring blades, and the rotating shaft, and it is up to the present invention.

  Reattachment of the coating film and sludge that has been peeled off from the recording material using a natural polymer binder and synthetic polymer binder on the support to form a coating film, the inner wall of the processing tank, stirring blades, rotation It is possible to provide a method of recovering the support in a state where it can be reused as a raw material for the support for recording materials by suppressing heat welding, etc. to the processing liquid such as the shaft and the contact portion. As a result, the recovery yield of the support that can be reused as the support material from the recorded material can be greatly improved. In addition, the treatment tank after the treatment can be easily cleaned and the working efficiency is improved.

  Embodiments according to the present invention will be described with reference to FIGS. 1 to 3, but the present invention is not limited thereto.

  FIG. 1 is a schematic view showing an example of a method for recovering a support.

  In the figure, reference numeral 1 denotes a first chemical processing unit that performs processing with an alkaline processing liquid. 101, while stirring the shredded chip-shaped recording material 102 having a coating film on a support in a processing tank 101a with an alkaline processing liquid 103 containing sodium hydroxide or potassium hydroxide with an agitator 101b. The processing apparatus which heat-processes and peels a coating film from a support body is shown.

  The solid content concentration when the chip-shaped recording material 102 is processed with the alkaline processing liquid 103 in the processing tank 101a is preferably 0.1 to 50% by mass. When the content is less than 0.1% by mass, the number of times the chip-shaped recording material collides with each other decreases, and the number of times the chip-shaped recording material collides with the blade decreases. Depending on the type of the recording material, the coating film is peeled off. In some cases, the amount of chip-shaped recording material that remains without being removed increases. When the amount exceeds 50% by mass, the treatment liquid cannot be sufficiently stirred, and a strong shearing force is not applied to the chip-shaped recording material. Therefore, depending on the type of the recording material, the coating film is not peeled off. The remaining chip-shaped recording material may increase. 101b1 indicates a motor for stirring, and 101b2 indicates a rotating shaft to which the stirring blade 101b3 is attached.

  The treatment with the alkaline aqueous solution 103 in the treatment tank 101a is performed by the following two-stage treatment including the first treatment and the second treatment while stirring with the stirring blade 101b3. The first treatment is performed at a temperature of 70 to 95 ° C. for 10 to 120 minutes, and the second treatment is performed at a temperature of 1 to 35 ° C. for 5 to 120 minutes. When the first process is finished, the second process is continued. In the first treatment, a high temperature treatment is performed to peel the coating film from the support. At a high processing temperature of 75 to 95 ° C., the peeled coating film is in a state in which the viscosity of the surface is increased, the elastic modulus is decreased, and adhesion is easy. For this reason, a part of the peeled coating film adheres to the support, the inner wall of the treatment tank, the stirring blade, and the rotating shaft. Also, the coating films adhere to each other. As for the sludge generated by the heat treatment, the viscosity of the surface increases, and a part of the generated sludge adheres to the support, the inner wall of the treatment tank, the stirring blade, and the rotating shaft in the same manner as the coating film. The support to which the coating film and the sludge are attached is also bonded to each other. When the process is completed in the first treatment stage and the process proceeds to the next process, the alkali treatment liquid is removed from the interface between the coating film adhering to the support and the sludge support, so that it adheres more strongly to the support. Since it becomes a state and cannot be removed until the final stage, it becomes a remaining impurity and is mixed into the recovered support, making it difficult to reuse it as a raw material for the support.

  Further, the coating film and sludge adhering to the inner wall of the processing tank, the stirring blade, and the rotating shaft are also firmly attached and difficult to remove as in the case of the support, and the working efficiency is remarkably lowered. Preventing such a state is the second process performed subsequent to the first process. In the second treatment, since the temperature is low, the surface of the peeled coating film is no longer viscous, and the elastic modulus is high, making it difficult to adhere. Also, the generated sludge is in a state where the surface has no viscosity and is difficult to adhere.

  By stirring in such a state, the coating film where the peeled coating films are attached, the support and the coating film where the coating film is peeled off, and the support where the sludge is attached are caused by the collision between the stirring blades and the supports. By applying the shearing force, the coating film and sludge adhering to the support are peeled off again. At the same time, the agglomeration and fixation of the coating films to which the separated coating films adhere are suppressed and separated. Further, the coating film and sludge adhering to the inner wall of the treatment tank, the stirring blade, and the rotating shaft are also peeled and removed by the collision of the support. The re-peeled coating film and sludge are not reattached because the temperature of the treatment liquid is low. By proceeding to the next step in such a state, separation of the support from the coating film and sludge is facilitated, and mixing into the recovered support is eliminated and the recording material can be reused as a raw material.

  Cleaning of the inner wall of the processing tank, the stirring blade, and the rotating shaft after processing becomes easy, and the working efficiency is greatly improved.

  When the temperature of the first treatment is less than 70 ° C., it is difficult to peel the coating film from the chip-shaped recording material, and it is not preferable because the processing time becomes long and the remaining coating film increases. When the temperature exceeds 95 ° C., excessive heat is applied to the chip-shaped recording material, and the polyester resin support is deteriorated by heat, which is not preferable.

  When the time of the first treatment is less than 10 minutes, the peeling of the coating film from the chip-shaped recording material does not end, and therefore, the remaining coating film is not preferable. Exceeding 120 min is not preferable because the polyester resin support of the chip-shaped recording material is decomposed by hydrolysis and changes in composition.

  When the temperature of the second treatment is less than 1 ° C., the solvent freezes and the stirring becomes poor, and it is not preferable because the shearing force is applied to the chip-shaped recording material and scratches, cracks, etc. occur due to excessive stirring. . When the temperature exceeds 35 ° C., the peeled coating film is viscous, and the coating film adheres to the polyester resin support, the inner wall of the treatment tank, and the stirring blade, which is not preferable.

  When the time of the second treatment is less than 5 minutes, the heating temperature by the first treatment cannot be sufficiently lowered, so that the viscosity remains on the peeled coating film, the coating film is a polyester resin support, the inner wall of the treatment tank, Since it adheres to a stirring blade, it is not preferable. If it exceeds 120 min, a shearing force is applied to the polyester resin support more than necessary, and scratches, cracks and the like are generated, which is not preferable.

  It is preferable to reduce the surface energy in order to prevent the coating film and sludge from adhering to the inner wall of the processing tank, the stirring blade, and the rotating shaft. For this purpose, the inner wall of the processing tank, the stirring blade, and the surface of the rotating shaft are heat resistant. It becomes possible by covering with a release coating.

As the heat-resistant release film to be used, a commonly used heat-resistant release film can be used, for example, tetrafluoroethylene (TFE), polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl. Vinyl ether copolymer (PFA), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (FEP), tetrafluoroethylene / ethylene copolymer (ETFE), polychlorotrifluoroethylene (trifluoride) (ECTFE), poly Vinylidene fluoride (difluoride) (PVDF), polyamideimide (PAI), polyethersulfone (PES), graphite-like carbon (GLC), diamond-like carbon (amorphous diamond) ) (DLC), SiC, TiN , TiCN, TiAl, TiCrN, CrN, SiO 2, SiZrO 4, ZrO 2 and the like.

  These heat-resistant release coatings can be formed by a general method, and examples thereof include a high temperature baking method, an electrodeposition method, and a room temperature spray coating.

  In this way, by coating the inner wall of the treatment tank, the stirring blade, and the rotating shaft that come into contact with the treatment liquid with the heat-resistant release coating, and the second treatment, the peeled coating film and the generated sludge are adhered. Can be prevented, cleaning after processing becomes easy, and work efficiency is improved.

  The chip-shaped recording material to be processed in the processing tank is preferably indeterminate with an outer size of 0.1 to 100 mm. The external size means a length twice the distance from the center (center of gravity) of the chip-shaped recording material to the vertex of the farthest corner. When the outer size is less than 0.1 mm, there is a risk of clogging the liquid feeding pipe depending on the thickness of each liquid feeding pipe of the collection method shown in FIG. Similarly, when the length exceeds 100 mm, there is a risk of clogging of the liquid feeding pipe depending on the thickness of each liquid feeding pipe of the recovery method shown in FIG. In addition, the alkali treatment may not sufficiently stir, the heat transfer efficiency may decrease, and the coating film may remain.

  By subjecting the chip-shaped recording material 102 to heat treatment by the processing apparatus 1, in the alkaline processing liquid 103, the peeled coating film, the support from which the coating film has been peeled, and the support in which a part of the coating film remains. And the generated sludge, the peeled coating film, the support to which the generated sludge adheres, and the like. In the present invention, all of these are referred to as a solid material.

  Examples of the chopped chip-shaped recording material 102 include discarded objects (for example, production scraps, defective products generated in the product inspection process) generated in the manufacturing process, used products, and the like.

  Reference numeral 2 denotes a first separation processing unit, which includes a hydrocyclone 201, a first collision type centrifugal dehydrator 202, and a draining means 203. There is no limitation in particular as the draining means 203, For example, an air cyclone, a screen conveyor, etc. are mentioned. In this figure, the case where an air cyclone is used is shown.

  Reference numeral 201a denotes a hopper that receives solids separated from the alkaline processing liquid by the hydrocyclone 201. Commercially available hydrocyclone 201, first collision type centrifugal dehydrator 202, and air cyclone 203 can be used, and the size can be appropriately selected from the processing amount.

  The first separation processing unit is a step of separating solids from the alkaline processing liquid of the previous step. The alkaline processing liquid containing the solid matter from the first chemical processing unit 1 is introduced from the upper part of the cylindrical portion 201b of the hydrocyclone 201 at a speed of 10 to 2500 m / min in the circumferential tangential direction of the hydrocyclone. Is preferred. If it is less than 10 m / min, the generation of eddy currents in the hydrocyclone main body becomes weak, and separation may not be possible depending on the state of solids in the alkaline processing liquid sent from the first chemical processing unit. When it exceeds 2500 m / min, depending on the state of solids in the alkaline processing liquid sent from the first chemical processing unit, solids may be clogged in the orifice 201 c below the hydrocyclone and separation may not be possible. .

  It is preferable to dilute the alkaline processing liquid with water so that the solid content concentration when introduced into the hydrocyclone 201 is 0.1 to 2% by mass. When the amount is less than 0.1% by mass, a large amount of water is used, which may be one of the causes of poor productivity. When the content exceeds 2% by mass, the hydrocyclone may be clogged depending on the size of the chip-shaped recording material.

  The alkaline treatment liquid introduced along the circumferential tangential direction of the hydrocyclone is separated and collected by the centrifugal force from the orifice 201c to the hopper 201a via the tapered portion 201e of the hydrocyclone 201, and the upper portion is discharged. From the outlet 201d, an alkaline treatment liquid containing a part of the peeled coating film and generated sludge or the like is discharged.

  From these solids, in order to separate and remove the coating film and sludge reattached to the support, the peeled coating film, sludge, etc., water is added from the hopper 201a to a solid content concentration of 0.1 to 50% by mass. It is adjusted and introduced from the lower part of the first collision type centrifugal dehydrator 202.

  While the solution introduced into the first collision type centrifugal dehydrator 202 moves to the upper part while colliding with each other, a part of the deposit and the peeled coating film, sludge and the like are discharged from the lower part 202a. From the upper part 202b, the support (including the support from which the coating film has been peeled off, the support from which a part of the coating film remains, and the support to which the peeled coating film and sludge are attached) cannot be separated. The peeled coating film and the like remaining on are discharged.

  The support discharged from the upper part 202b of the first collision type centrifugal dehydrator 202 (the support from which the coating film was peeled off, the support from which a part of the coating film was left, the peeled coating film, sludge, and the like adhered. In addition, the peeled coating film remaining without being separated is introduced into an air cyclone serving as a draining means, and the adhering water is removed.

  The solids collected at this stage were generated by the support from which the coating film was peeled off, the support from which a part of the coating film remained, the support from which the peeled coating film was reattached, and the alkaline processing liquid. Since the support to which sludge and the like are attached, the peeled coating film, and the sludge and the like generated by the alkaline processing liquid are mixed, it is not yet in a state where it can be reused for the support of the recording material.

  Reference numeral 3 denotes a second separation processing unit, which has a high shear stirring device 301 and a second collision type centrifugal dehydrator 302. Commercially available high shear agitator 301 and second collision type centrifugal dehydrator 302 can both be used, and the size can be appropriately selected in accordance with the processing amount.

  The second separation processing unit 3 is configured to remove the coating film and sludge by the physical force from the support to which the separated coating film and sludge and the like collected by the first separation processing unit are attached. This is a step of subdividing the membrane to facilitate removal and separating the support.

  The solid matter recovered by the first separation processing unit 2 is adjusted to a solid content concentration of 0.1 to 50% by mass with water, and is put into the high shear stirring device 301. The mechanism and processing conditions of the high shear stirring device 301 will be described with reference to FIG.

  The solid matter is processed by applying a high shearing force with the high shear stirring device 301, so that the coating film remaining on the support, the coating film adhering thereto, sludge, etc. are peeled off and simultaneously subdivided. . Similarly, the peeled coating film, sludge and the like remaining without being separated are subdivided by being treated by applying a high shearing force to form a solution mixed with water.

  In this state, the support is separated from the coating film, sludge, and the like by being introduced into the second collision type centrifugal dehydrator 302 and processed, and the support is recovered. When the support is recovered from the second collision type centrifugal dehydrator 302, the support may be recovered via an air cyclone as shown in the first separation processing unit. Since the support recovered at this stage contains a support with a small amount of coating film, sludge, etc., and a subdivided coating film, etc., it is still reused as a recording material support. It is not in a state where it can be done. The mechanism and conditions of the second collision type centrifugal dehydrator 302 will be described with reference to FIG.

  Reference numeral 4 denotes a second chemical processing unit for processing the support recovered from the second separation processing unit 3 with an acidic processing solution that can be reused as a recording material support. 401, the support 402 collected from the second collision-type centrifugal dehydrator 302 placed in the treatment tank 401a is treated with the acidic treatment liquid 403 at a temperature of 1 to 95 ° C. with the stirrer 401b while the support is treated. A processing device is shown. By the treatment with the acidic treatment liquid, a slight coating film, sludge, and a fine coating film binder adhering to the support 402 are decomposed, and silver can be separated and removed as silver nitrate. .

  The support recovered at the stage where the treatment with the acidic processing liquid is completed has no adhesion of foreign matter, and is separated from the acidic processing liquid by the same level as the support used in the production of the recording material. It is in a state that can be reused for the support.

  The acidic treatment liquid used in the second chemical treatment section is not particularly limited, and examples thereof include nitric acid, hydrohalic acid, sulfuric acid and the like, and nitric acid and hydrohalic acid are particularly preferable. The concentration of the acidic treatment liquid is preferably 0.01 to 10 mol / L. When it is less than 0.01 mol / L, the binder of the coating film may not be decomposed depending on the type of binder, and silver may not be eluted into the solution. If it exceeds 10 mol / L, depending on the material used in the equipment, corrosion may progress and hinder production.

  Reference numeral 5 denotes a water washing / drying section. The water washing / drying unit 5 is a step of separating, washing, and drying the support treated with the acidic solution in the chemical treatment unit 4.

  Reference numeral 501 denotes a water washing apparatus, and 502 denotes a drying apparatus. The washing apparatus 501 is not particularly limited as long as the recovered support can be efficiently washed. For example, the washing apparatus 501 may be a washing tank equipped with a stirrer, or a mesh drum type container that can be rotated while the washing water is lost in the shower. But it ’s okay. When the drying is completed by the drying apparatus, the recovery of the support that can be reused as the raw material of the recording material support is completed.

  The drying device 502 is not particularly limited as long as the drying device 502 can be efficiently dried similarly to the water washing device 501, and may be, for example, a mesh drum type container that can be rotated while blowing drying air.

  It is preferable that all of the first chemical processing unit, the first separation processing unit, the second separation processing unit, the second chemical processing unit, and the water washing / drying unit shown in FIG.

  Next, the mechanism and processing conditions of the high shear stirring apparatus according to the present invention will be described.

  FIG. 2 is a schematic view of a Henschel mixer, which is a high shear stirring device of the second separation processing unit of FIG. FIG. 2A is a schematic cross-sectional view of a Henschel mixer. FIG. 2B is a schematic perspective view of the lower blade of the Henschel mixer. FIG. 2C is a schematic perspective view of the upper blade of the Henschel mixer.

  In order to recover only the support from the solids recovered in the first separation processing unit, a high shear force is applied to these, and the coating film remaining on the support, the coating film reattached to the support, and As a result of the examination, it has become clear that it is most effective to peel and remove sludge and the like and to subtract and remove the mixed coating film.

  The coating film remaining on the support is in a state in which the alkaline treatment liquid is infiltrated into the undercoat layer at the stage where the treatment with the alkaline treatment liquid has been completed, so peeling is promoted by applying a high shear force to the coating film. It is easy to be done. Moreover, peeling is promoted by applying a high shearing force to the coating film, sludge and the like adhering to the support. The peeled coating film, sludge and the like are subdivided by applying a high shearing force, and are easily separated from the support in the next step.

  A Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) can be cited as an optimal apparatus that applies a high shear force evenly. In this figure, a case where a Henschel mixer is used as a high shear stirring device will be described.

  In the figure, 301a represents a bottomed cylindrical body of the Henschel mixer, and 301b represents a lid. 301c shows a rotating shaft, 301d shows the lower blade | wing attached to the rotating shaft 31c, 301e shows the upper blade | wing attached to the rotating shaft 301c. As the rotating shaft rotates (in the direction of the arrow in the figure), the liquid in the body 301a generates a flow in two directions. One is the upward flow from the bottom (in the direction of the arrow in the figure) due to the rotation of the lower blade 301d. The other is a horizontal flow (in the direction of the arrow in the figure) generated by the rotation of the upper blade 301e. When solids are present in the processing liquid, the solids are once subjected to an upward flow, and then are subjected to a downward flow and contact with the upper blade to be subjected to a shearing force. By applying a high shearing force uniformly to each solid matter by processing for a certain period of time with a Henschel mixer that generates such a flow, the coating film remaining on the support, the coating film and sludge that had adhered, When the coating film remaining without being separated is peeled off, it is shredded and subdivided to facilitate separation in the next step.

  The shape of the lower blade and the upper blade is not particularly limited, and can be appropriately selected depending on the type of the object to be stirred and the concentration of the solid material.

  Preferred conditions in the Henschel mixer 301 include the following conditions. The solid content concentration is preferably 1 to 70% by mass. When the amount is less than 1% by mass, the swirl flow in the tank becomes dominant, the axial flow is not generated, and the pulverization by the upper blade may not be possible depending on the kind of the object to be stirred and the kind of the solid substance. If it exceeds 70% by mass, depending on the type of solid matter, bridging is likely to occur and uniform stirring may not be possible.

  The rotation speed of the blade (the peripheral speed at the tip of the blade) is preferably 10 to 70 m / sec. If it is less than 20 m / sec, the shearing force applied to each solid matter becomes small, and depending on the state of the applied coating film and sludge, it may not be peeled off or the peeled coating film may not be fragmented. When it exceeds 70 m / sec, depending on the type of coating film, the temperature of the peeled coating film rises with stirring, and depending on the type of binder used in the coating film, the viscosity increases and softens and peels. The coating film may adhere to the support again, and it may be difficult to peel off the coating film that has been reattached in the subsequent steps.

  The time is preferably 10 to 30 minutes. If it is less than 10 minutes, the peeling may not be completed depending on the type of coating film and the state of adhering foreign matter. If it exceeds 30 minutes, the internal temperature rises and the viscosity increases and softens depending on the type of binder used in the coating, and the peeled coating adheres to the support again. It may be difficult to peel off the attached coating film.

  The temperature is preferably 1 to 40 ° C. When the temperature is lower than 1 ° C., depending on the type of contents, solidification may occur partially and complete flow may not be possible. When it exceeds 40 ° C., depending on the type of coating film, it may start to become viscous and reattach to the support.

  FIG. 3 is a schematic view of the second collision type centrifugal dehydrator shown in FIG. FIG. 3A is a schematic sectional view of the second collision type centrifugal dehydrator shown in FIG. FIG. 3B is a schematic plan view of a collision type centrifugal dehydrator.

  In the figure, 302a indicates a cylindrical outer cylinder of a collision type centrifugal dehydrator, and 302b indicates a rotating rotor disposed inside the outer cylinder 302a. 302c shows a cylindrical separation cylinder. Reference numeral 302d denotes a motor for driving the rotary rotor 302b. Reference numeral 302c1 denotes a hole provided in the cylindrical separation cylinder 302c. Reference numeral 302b1 denotes a stirring blade attached to the surface of the rotating rotor 302b. When the rotary rotor 302b is rotated (in the direction of the arrow in the figure), the stirring blade is fed with the processing liquid processed by the high shear stirring device inserted from the supply port 304 into the gap 303 between the separation cylinder 302c and the outside of the rotary rotor 302b. It is attached at an angle that results in upward flow. Centrifugal force is applied by rotating the rotating rotor 302b, and the coating film, sludge and treatment liquid peeled off from the support are removed from the holes provided in the separation cylinder 302c, and the support is not passed through the remaining upper portion. Is discharged and separated from the outlet 305 of the printer. The coating film and the treatment liquid mixed with the adhering material that have passed through the holes are discharged from the discharge port 306 at the lower part of the outer cylinder 302a. The size of the hole 302c1 is preferably 1/10 to 1/2 with respect to the size of the chip-shaped recording material cut into pieces. If it is less than 1/10, depending on the size of the peeled coating film and the size of the deposit, it may not be removed without passing through the hole. When the ratio exceeds 1/2, the support may be removed depending on the size of the support. Note that the size of the chip-shaped recording material that has been chopped indicates an average value obtained by measuring 100 g of the chip-shaped recording material that has been chopped and measuring the maximum length of each chip. The shape of the hole 302c1 is not particularly limited, but a circular shape is preferable from the viewpoints of cleaning the separation cylinder, maintaining strength, and making it easily.

  The aperture ratio of the holes 302c1 provided in the separation cylinder 302c (the total area of the holes / total surface area of the separation cylinder × 100) is preferably 10 to 80%. Furthermore, 30 to 60% is preferable. If it is less than 10%, depending on the concentration of solids in the treatment liquid, it may take time to separate, and work efficiency may deteriorate. If it exceeds 80%, the strength may be insufficient depending on the material of the separation cylinder, and it may take time and cost for maintenance of the separation cylinder, resulting in poor production efficiency.

  The shape of the rotating rotor 302b is not particularly limited as long as it can rotate at high speed, and may be, for example, a cylindrical shape or a polygonal cylindrical shape. This figure shows a cylindrical shape. The first collision type centrifugal dehydrator used in the first separation processing unit has the same structure as the second collision type centrifugal dehydrator shown in the figure.

  The amount of the processing liquid to be put into the collision type centrifugal dehydrator can be appropriately determined depending on the solid content concentration and the size of the collision type centrifugal dehydrator. The rotational speed (circumferential speed) of the rotating rotor is preferably 5 to 40 m / sec. In the case of less than 5 m / sec, the size of the support on which a part of the coating film in the treatment liquid remains, the peeled coating film, sludge generated by the alkaline treatment liquid treatment, and the peeled coating film are attached. Depending on the situation, solids do not roll up in the collision type centrifugal dehydrator, there is no collision between these supports, and sludge generated by the coating film and alkaline treatment liquid treatment may not be separated. If it exceeds 40 m / sec, the support is damaged by the blades of the rotor and miniaturization proceeds, so depending on the size of the hole provided in the separation cylinder, the refined support is removed and the recovery rate is greatly increased. May fall.

  The following effects can be mentioned as an effect of cutting the recording material using the polyester resin support by using the method shown in FIGS.

  1) Since the coating film peeled off by the treatment with the alkaline processing liquid and the generated sludge are not reattached to the support, the purity of the recovered support is high, and the raw material of the support of the recording material (support of the photosensitive material) It can be reused as a body raw material).

  2) The recovery rate of the support having high purity can be improved.

  3) Processing in the processes after the first chemical processing section with the alkaline processing liquid is facilitated, and the working efficiency can be improved.

  4) The treatment tank after the treatment with the alkaline treatment liquid can be easily cleaned and the working efficiency can be improved.

  5) Along with the fact that it can be reused, the need for incineration or landfilling is eliminated, and the environmental burden can be reduced.

  The support according to the present invention is not particularly limited. For example, JP 2000-206646, 2001-290243, 2002-99063, 2002-116320, 2002-131872, 2002-250990, 2003-1774, etc. The thing of description is mentioned.

  The recording material using the support according to the present invention can be any recording material in which a coating film is formed using a natural polymer binder and a synthetic polymer binder. Examples of the recording material using the natural polymer binder include medical, printing and general silver halide photographic light-sensitive materials.

  Examples of the recording material using the synthetic polymer binder applied to the polyester resin support recovery method of the present invention include a photothermographic material and a radiation image conversion sheet. In particular, JP-A-9-292671, JP-A-9-304870, JP-A-9-304871, JP-A-9-304882, JP-A-10-31282, JP-A-10-62898, JP-A-11-295844, and JP-A-11 The photothermographic material disclosed in Japanese Patent No. -352627 is preferred.

  In the present invention, examples of the transparent or translucent natural polymer and synthetic polymer binder used for the coating film formed on the support include the following. Examples of natural polymer binders include: gelatin, gum arabic, casein, starch and the like. Examples of synthetic polymer binders include: polyvinyl alcohol, hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, polyvinyl pyrrolidone, polyacrylic acid, polymethyl methacrylic acid, polyvinyl chloride, polymethacrylic acid, styrene-maleic anhydride copolymer Styrene-acrylonitrile copolymer, styrene-butadiene copolymer, polyvinyl acetals (for example, polyvinyl formal and polyvinyl butyral), polyesters, polyurethanes, phenoxy resins, polyvinylidene chloride, polyepoxides, polycarbonates, polyvinyl acetate, Cellulose esters and polyamides are widely used.

  As a binder used for a coating film, any of a hydrophobic resin and a hydrophilic resin may be used, and they are properly used according to their suitability.

Preferable hydrophobic resins include polyvinyl butyral resin, cellulose acetate resin, cellulose acetate butyrate resin, polyester resin, polycarbonate resin, polyacrylic resin, polyurethane resin, and vinyl chloride resin.
Hereinafter, although an example is given and the concrete effect of the present invention is shown, the mode of the present invention is not limited to this.

Example 1
(Preparation of chip-shaped recording material)
A chip-shaped recording material having a size of 10 mm × 10 mm (outside size 14 mm) (a half-cut size of SD-P (photothermographic material) manufactured by Konica Minolta MG Co., Ltd.) (260 kg) was prepared.

<Recovery of support>
Processing was sequentially performed according to the method shown in FIG.

(Setting of processing conditions with alkaline processing liquid)
As shown in Table 1, the processing conditions with changing the processing temperature and time were set to 1-1 to 1-26.

(Preparation of processing equipment)
A treatment tank with a stainless steel heating jacket with an inner diameter of 50 cm and a height of 70 cm is prepared. The rotation diameter is 40% of the inner diameter of the treatment tank, and the rotation volume when the blade is rotated is the capacity of the treatment liquid in the treatment tank. The processing tank is attached to the rotary shaft so that the vertical distance from the liquid level of the processing tank is 0.3 with respect to the depth of the processing liquid, using a stainless steel stirring blade of 10% blades. Arranged inside. In addition, the inner wall of the treatment tank in contact with the treatment liquid, the stirring blade, and the rotating shaft were coated with a heat-resistant release film made of titanium nitride (TiN).
(Treatment of support from alkaline treatment liquid and treated alkaline treatment liquid)
100 L of a sodium hydroxide solution having a concentration of 1 mol / L was placed in a treatment tank, the prepared chip-shaped recording material (SD-P) was stirred, and the treatment was performed under the treatment conditions shown in Table 1. Each treatment was 10 kg each of the prepared chip-shaped recording material (SD-P). Stirring was performed at a stirring speed (circumferential speed of stirring blades) of 5 m / sec. After the treatment, each of the treated alkaline treatment liquids was treated with a first separation part, a second separation part, an acidic treatment liquid, washed with water, and dried as shown in FIG.

<Separation process by the first separation unit>
(Separation by hydrocyclone)
The hydrocyclone shown in FIG. 1 was used to separate solids from the treated alkaline processing liquid. The hydrocyclone used has a cylindrical part length of 0.45 m, a cylindrical part inner diameter of 0.3 m, a conical part length of 0.45 m, a conical part taper degree of 15%, and an orifice inner diameter of 5 cm. Thus, the treated alkaline treatment liquid was introduced into the hydrocyclone in the circumferential tangential direction at a flow rate of 100 m / min.
(Separation by the first collision type centrifugal dehydrator)
From the lower part of the first collision type centrifugal dehydrator shown in FIGS. 1 and 3, water is further added to the solid matter separated from each treated alkaline treatment liquid by the hydrocyclone to adjust the solid content concentration to 50 mass%. The mixed solution was introduced at a flow rate of 5 m / min to separate a part of the unnecessary matter. The first impingement type centrifugal dehydrator used has an outer cylinder diameter of 0.4 m, a height of 1.5 m, and a rotating rotor with a diameter of 0.3 m and a diameter of 1.5 m. ) Was performed at 15 m / sec. The separation cylinder has a circular hole with a diameter of 2 mm (about 1/5 of the size (outside size) of the chip-shaped SD-P) arranged in a plover shape at intervals of 3 mm, and has an opening rate of 40%. It was used.
(Separation of moisture and other deposits by air cyclone)
From the upper part of the first collision type centrifugal dehydrator, the solid matter separated from each treated alkaline treatment liquid and discharged was separated by air cyclone from the adhering moisture and other deposits.

<Separation of coating film, sludge, etc. from solids by the second separation processing unit>
In order to remove the coating film remaining on the support, the adhering sludge and coating film, the separated coating film remaining without separation, and the like from the solid separated by the first separation processing unit. The process by the 2nd separation process part shown by 1 was performed.

(Mixing with high shear stirrer)
A Henschel mixer (FM20C / L manufactured by Mitsui Mining Co., Ltd., the upper blade is Yi blade, and the lower blade is So blade) was used as the high shear stirring device. In order to process the separated solid matter using the Henschel mixer shown in FIGS. 1 and 2, water was added to adjust the solid concentration to 50% by mass. The treatment liquid thus prepared was treated with a Henschel mixer at a blade rotation speed (peripheral speed at the tip of the blade) of 40 m / sec and a temperature of 30 ° C. for 10 minutes.
(Separation by the second collision type centrifugal dehydrator)
The mixed solution mixed by the Henschel mixer is introduced from the lower part of the second collision type centrifugal dehydrator shown in FIGS. 1 and 3 at a flow rate of 5 m / min to separate the support from the solid matter. It was. The second collision-type centrifugal dehydrator used was the same as the first collision-type centrifugal dehydrator and was processed under the same conditions.

(Treatment with acidic solution)
In order to remove foreign matter from the solid matter (support) separated by the second collision type centrifugal dehydrator, it was treated with a 5 mol / L nitric acid solution at a temperature of 50 ° C. for 60 minutes, followed by washing with water and drying. It was.

(Evaluation)
The obtained samples 101 to 126 are subjected to molecular weight measurement, coloring degree measurement, and foreign matter adhesion observation, and the results of evaluation according to the following evaluation rank are shown in Table 2. The molecular weight was measured using a viscosity measuring device SS-270LC-1 manufactured by Shibayama Scientific Machinery Co., Ltd. and converted from the obtained viscosity. For the coloring degree measurement, each sample was used, and a 0.5 mm thick plate was prepared using an injection molding machine AU3E manufactured by Nissei Plastic Industry Co., Ltd. Each plate was measured using a spectrophotometer U-3210 manufactured by Hitachi, Ltd.

Evaluation rank of molecular weight ○: Difference from the reference sample is less than 10% Δ: Difference from the reference sample is less than 10 to 30% ×: Difference from the reference sample is 30% or more Note that the reference sample used for the evaluation is immediately after film formation The support was used.

Evaluation rank of coloring degree ○: The difference with respect to the reference sample is less than 3% △: The difference with respect to the reference sample is less than 3-5% ×: The difference with respect to the reference sample is 5% or more Immediately after the support was chopped, a product with a 0.5 mm thick plate was used using an injection molding machine AU3E manufactured by Nissei Plastic Industry Co., Ltd. in the same manner as each sample.

Observation of foreign matter 10 g of each sample 101 to 126 was sampled arbitrarily, and the presence or absence of foreign matter was confirmed visually.

Evaluation rank of foreign matter adhesion ○: No foreign matter adhesion is observed on all the collected supports Δ: One to four foreign matters having a diameter of about 0.1 mm are attached to one of the collected supports × : Five or more foreign matters having a diameter of about 0.1 mm are attached to one of the collected supports.

  From the above results, it was confirmed that a support having the same purity as that of PET before use was recovered, and the effectiveness of the present invention was confirmed.

Example 2
(Preparation of processing equipment)
When the sample 121 was produced in Example 1, the inner wall of the treatment tank of the treatment apparatus, the stirring blade, and the rotating shaft were coated with a heat-resistant release coating as shown in Table 3 to obtain 2-1 to 2-5. In addition, except not covering with a heat-resistant release film, the processing apparatus of the same conditions was prepared and it was set as the comparison processing apparatus 2-6.

a: PTFE
b: PES
c: DLC
d: TiN
e: SiZrO ₄
(Cleaning of processing equipment)
Except for using the processing apparatus shown in Table 3, after performing the treatment with the alkaline treatment liquid under the same conditions as the sample 121 of Example 1, the treatment tank was emptied, the inner wall of the treatment tank, the stirring blade, Table 4 shows the time required for cleaning the rotating shaft. The cleaning was performed manually using normal temperature running water and a nylon brush.

  From the above results, the effect of covering with the heat-resistant release coating was confirmed, and the effectiveness of the present invention was confirmed.

Example 3
When the sample 121 of Example 1 was manufactured, the chip-shaped recording material (SD-P) was processed under the same conditions except that the outer size as shown in Table 5 was used, and the support was recovered. Samples 301 to 307 were used.

(Evaluation)
Table 5 shows the results obtained by performing molecular weight measurement, coloring degree measurement, and foreign material adhesion observation on the obtained samples 301 to 307 in the same manner as in Example 1 and evaluating according to the same evaluation rank as in Example 1.

  From the above results, it was confirmed that a support having the same purity as that of PET before use was recovered, and the effectiveness of the present invention was confirmed.

It is a schematic diagram which shows an example of the collection | recovery method of a support body. It is the schematic of the Henschel mixer which is a high shear stirring apparatus of the 2nd separation process part of FIG. It is the schematic of the 2nd collision type centrifugal dehydrator shown in FIG. It is a schematic sectional drawing of a photographic photosensitive material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st chemical processing part 101,401 Processing apparatus 101a Processing tank 101a1 Bottom face 101b2 Rotating shaft 101b3 Stirring blade 2 First separation processing part 201 Hydrocyclone 202 First collision type centrifugal dehydrator 3 Second separation processing part 301 High shear stirring apparatus 302 Second collision type centrifugal dehydrator 4 Second chemical treatment section 5 Water washing / drying section 501 Water washing apparatus 502 Drying apparatus 6 Photosensitive material

Claims (4)

A chip-shaped recording material having at least one coating film on a polyester resin support is treated with an alkaline treatment liquid in a treatment tank using a stirrer, and the polyester resin support is separated from the alkaline treatment liquid. Then, in the polyester resin support recovery method of recovering the polyester resin support,
The treatment with the alkaline treatment liquid is performed in two stages of a first treatment at a temperature of 70 to 95 ° C. and a time of 10 to 120 min and a second treatment at a temperature of 1 to 35 ° C. and a time of 5 to 120 min. Polyester-based resin support recovery method. The polyester resin support recovery method according to claim 1, wherein an inner surface of the treatment tank is coated with a heat-resistant release film. The method for recovering a polyester resin support according to claim 1 or 2, wherein the coating film uses a natural polymer binder or a synthetic polymer binder. The polyester-based resin support recovery method according to any one of claims 1 to 3, wherein the chip-shaped recording material is an indeterminate shape having an outer size of 0.1 to 100 mm.

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