JP2012076313A - Method of recovering resin substrate and apparatus for recovering resin substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for peeling an adhered material being a coating film or a coating agent from the surface of the resin substrate at the recovery of the resin substrate.SOLUTION: A method of recovering the resin substrate comprises steps for: adding a granular material into a liquefied gas which is liquefied at a temperature equal to or lower than a predetermined temperature; immersing the resin substrate on the surface of which the adhered material is stuck; making the liquefied gas flow; adding the granular material into the liquefied gas to collide with the resin substrate; and thereby peeling the adhered material by the impact of the collision.

Description

  The present invention relates to a technique for peeling a coating film or a coating agent on the surface of a resin base material in the recovery of the resin base material.

  CD (Compact Disc) and DVD (Digital Versatile Disc) discs collected as waste, or housings such as PCs (Personal Computers) and mobile phones are painted and coated on the surface of the resin base material. . When such a resin base material is regenerated as a material, it is necessary to remove the coating film on the surface and the adherend of the coating agent. This is because these adherends are generally impurities for the resin base material, and the impurities are mixed to impair the properties of the resin base material and reduce the quality of the recycled material.

  As a method for peeling an adherend from a resin base material, a method using a solvent is known. In this method, a resin base material to which an adherend is attached is immersed in an alkaline solution heated to 75 to 100 ° C., and then peeled off by stirring.

  As a method of recovering plastic from a composite material without using an alkaline solution, a method of applying a shear load while cooling is known. In this method, the composite material is cut into small pieces, and the prepreg material is peeled off by applying a shearing load while cooling to +5 to -10 ° C. to recover the plastic.

Japanese Patent Laid-Open No. 04-360035 JP 09-94476 A

  As described above, in order to regenerate the resin base material that is a waste material, it is necessary to remove the adherend of the coating film or coating agent applied to the surface. The method of immersing in a heated alkaline solution known as a method for peeling the adherend from the resin substrate can efficiently peel the surface adherend from the resin substrate, but the resin substrate is placed under heating, There is concern about deterioration of physical properties due to immersion in an alkaline solution, and there is a problem in quality as a recycled material. Moreover, it is necessary to neutralize or wash the alkaline solution adhering to the resin substrate after peeling, and there are also economic problems such as the cost required for these steps and the cost required for waste liquid treatment.

  The method of applying a shear load while cooling the waste material does not use an alkaline solution, so it can avoid the problems described above (deterioration of physical properties and cost required for neutralization, etc.), but peels the prepreg material from the composite material. As described above, it is difficult to peel the coating film or coating agent from the resin base material, which is not suitable for solving the problem intended by the present invention.

  An object of the present invention is to provide a resin base material recovery method and a resin base material recovery device that efficiently peel off an adherend adhered to a surface without impairing the quality of the resin base material when recovering the resin base material from waste materials. And

  According to one aspect of the invention, the resin base material recovery method of the present invention adds a granular material to a liquefied gas that is liquefied at a predetermined liquefaction temperature or lower, and the resin base material with an adherend on the surface is added to the liquefied gas. There is provided a method for recovering a resin base material, in which the liquefied gas is flowed and the granular material added to the liquefied gas collides with the resin base material to peel off the adherend.

  According to another aspect of the invention, the resin base material recovery apparatus of the present invention includes an immersion tank for storing a liquefied gas that is liquefied below a predetermined liquefaction temperature, and a circulator that is connected to the immersion tank and circulates the liquefied gas. A resin base material recovery apparatus comprising: a hopper for charging the granular material into the dipping tank; a net-like basket containing a resin base material with an adherend on the surface; and a lifting mechanism for moving the basket up and down Is provided.

  By applying a mechanical impact to the adherend on the resin base material that becomes brittle and easily peeled off at low temperatures, the resin base material is recovered by efficiently peeling without damaging the quality of the resin base material. be able to.

It is a structural example of the resin base material collection | recovery apparatus of this invention. It is an example of the addition state of PC resin filler. It is an example of the shape of the protrusion provided in the basket. It is an example of a treatment result of adherend peeling. It is an example of a measurement result of melt fluidity of recovery PC resin. It is an example of the collection process of a resin base material.

  Embodiments of the resin base material recovery method and the resin base material recovery apparatus of the present invention will be described with reference to FIGS. Here, an example will be described in which a CD or DVD disk based on PC (polycarbonate) resin is used as the waste material and liquid nitrogen is used as the liquefied gas. Further, it is assumed that the surface of the disc is provided with a printing film on which recorded contents are printed, a protective film for protecting the recording surface, and the like.

  First, the structural example is demonstrated about the resin base material collection | recovery apparatus 100. FIG. FIG. 1 is a diagram illustrating the configuration of a resin base material recovery apparatus 100. FIG. 1 (a) is a view showing the resin base material recovery apparatus 100 in cross section, and FIG. 1 (b) is a view as seen from above. . As shown in both figures, the resin base material recovery apparatus 100 has an immersion tank 200, a basket 300, and a hopper 400.

  The immersion tank 200 is a tank in which the liquid nitrogen 20 is stored in the tank and the waste material 10 placed in the basket 300 is immersed in the liquid nitrogen 20. An inlet 250 is provided at the bottom of the immersion bath 200, and the liquid nitrogen 20 flows through the inlet 250. Moreover, the upper part of the immersion tank 200 is provided with an overflow receiver 210 from which the liquid nitrogen 20 flows out from the edge. The liquid nitrogen 20 flowing out of the overflow receiver 210 flows into the storage tank 220 through the pipe, and the liquid nitrogen 20 is temporarily stored here. Is done.

  An outlet 230 through which liquid nitrogen 20 flows is provided at the bottom of the storage tank 220, and the outlet 230 is provided with a filter 231. The outlet 230 is connected to the circulator 240, and the circulator 240 is connected to the inlet 250 of the immersion tank 200 described above. The circulator 240 pressurizes the liquid nitrogen 20 flowing into the circulator 240 and sends it out to the inlet 250. When the liquid nitrogen 20 is pressurized and sent out, the liquid nitrogen 20 circulates and flows in the immersion tank 200, the overflow receiver 210, the storage tank 220, the circulator 240, and the immersion tank 200. The adherends peeled off from the resin base material by the processing described later are mixed in the liquid nitrogen 20, but these adherends are captured by the filter 231 described above.

  In addition, the storage tank 220 is provided with a level meter 270 that measures the liquid level of the liquid nitrogen 20. When the liquid level of the liquid nitrogen 20 becomes lower than a predetermined height, the liquid nitrogen replenishing valve 280 is opened and the liquid nitrogen is opened. 20 can be replenished. The piping of the liquid nitrogen replenishing valve 280 is in contact with a liquid nitrogen tank (not shown).

  The basket 300 is a container for storing the waste material 10 to be treated, and is connected to the agitator 310. Furthermore, the basket 300 and the stirrer 310 are connected to an elevator mechanism (not shown) by an elevator connection part 320.

  The basket 300 is formed of a net knitted wire, and the liquid nitrogen 20 easily flows into and out of the basket 300 when immersed in the liquid nitrogen 20 of the immersion tank 200. The mesh of the bottom surface of the basket 300 and the lower side surface connected to the bottom surface is slightly fine so that it does not spill from the mesh when the crushed waste material 10 is generated, and the liquid nitrogen 20 easily flows in and out of the mesh on the other side surface. Is getting bigger. The shape of the basket 300 shown in FIG. 1A is a cylindrical shape having a diameter of 600 mm and a height of 600 mm.

  In addition, a plurality of protrusions 302 projecting inward are provided inside the basket 300. FIG. 2 shows an example in which the protrusions 302 are provided on the wire 301 that forms the basket 300. The protrusion 302 shown in FIG. 2 has a length of 25 mm and a height of 8 mm, and has a substantially trapezoidal cross section and is welded to the wire 301. By providing such protrusions 302, when the waste material put in the basket 300 is stirred by the stirrer 310, the waste material 10 is actively moved in the basket 300 to prevent the waste materials 10 from overlapping each other. Here, SUS (Stainless Used Steel) is used as the material of the wire 301 and the protrusion 302 of the basket 300. As long as the material is hard and does not corrode, it may be a substitute for SUS.

  The stirrer 310 alternately rotates and reversely rotates the basket 300 at predetermined time intervals (the arc arrow in FIG. 1A indicates the rotation direction), and stirs the waste material 10 in the basket 300.

  A lifting mechanism (not shown) lowers the basket 300 connected to the stirrer 310 into the immersion tank 200 and immerses it in the liquid nitrogen 20 in the recovery process of the resin base material. Moreover, the basket 300 is raised at the time when the processing is completed, and is taken out from the immersion tank 200 (up and down arrows in FIG. 1A indicate the ascending / descending direction of the elevating mechanism).

  The hopper 400 is a container for containing the resin filler 30 to be added to the liquid nitrogen 20, and is provided on the cover 260 at the upper part of the immersion tank 200. Before putting the basket 300 containing the waste material 10 into the immersion tank 200, a discharge valve (not shown) at the bottom of the hopper 400 is opened, and a predetermined amount (approximately 5 to 10% of the weight of the waste material 10) of the resin filler 30. Into liquid nitrogen 20. The resin filler 30 is irregular particles having a size of about 100 μm to 1 mm. In this embodiment, the resin base material of the disk is a PC resin, and therefore a PC resin filler is used. The resin filler 30 is added to the liquid nitrogen 20 and flows in the immersion tank 200 by the circulator 240, and peels off the adherend that has become brittle at low temperature by colliding with the waste material 10 in the basket 300. Do. The reason why the resin filler 30 is indefinite is that the force acting when the resin filler 30 collides with the waste material 10 due to the shape of the resin filler 30 forming various surfaces and angles is large. Moreover, by making the resin filler 30 the same material as the resin base material, it is not necessary to separate the resin filler 30 attached to the resin base material at the time of recovery.

  FIG. 3 shows an image of the resin filler 30 attached to the waste material 10 in the basket 300. A part of the resin filler 30 is taken out from the basket 300 in a state of adhering to the resin base material after the processing is completed, but is, for example, the same material as the resin base material even when melted for pelletization as a recycled product. There is no problem. The resin filler 30 corresponds to the granular material described above.

  In the resin base material recovery apparatus 100 described above, the waste material 10 is manually input into the basket 300, but thereafter, the processing of the resin base material recovery apparatus 100 proceeds by a control device (not shown). Next, the process flow of the resin base material collection | recovery apparatus 100 is demonstrated using FIG. In the description of the processing flow, it is assumed that the resin base material recovery apparatus 100 is in the initial state, the basket 300 is raised by the lifting mechanism, and the liquid nitrogen 20 is filled in the immersion tank 200.

  First, the waste material 10 is put into the basket 300. The waste material 10 is manually input. In the present embodiment, the disk is used as the waste material 10 as described above, and the size of the waste material 10 (diameter 120 mm) is sufficiently small with respect to the size of the basket 300 (a cylindrical shape of 600 mmφ). When the size of the waste material 10 is large, it is crushed as appropriate. Further, the weight of the waste material 10 to be processed is measured so as to be 1 kg, and the weight (processing amount) put into the basket 300 is adjusted (S1. Step 1 is denoted as S1).

  After throwing the waste material 10 into the basket 300, the operator turns on the processing start switch of the control device of the fat base material recovery device 100, and the subsequent steps are processing based on the command of the control device. The control device opens the discharge valve of the hopper 400 and adds the resin filler 30 made of PC resin to the liquid nitrogen. 50 g of resin filler 30 is supplied by opening and closing the discharge valve. This 50 g corresponds to 5% with respect to 1 kg of the waste material 10 (S2).

  Subsequently, the basket 300 is lowered by the lifting mechanism, and the basket 300 is submerged (immersed) in the immersion tank 200. When the basket 300 is lowered to a predetermined lowered position, the stirrer 310 is operated to start stirring. Stirring is performed by changing the direction of rotation to the left and right, for example, every 10 seconds. The number of rotations in each direction is 60 rpm. Stirring is performed for a predetermined time (here, 30 min) (S4, S5).

  The adherend of the waste material 10 is immersed in the liquid nitrogen 20 so that the adherend becomes brittle and easily peels off, and the adherend is separated from the resin base material by the collision between the resin filler 30 and the waste material 10. By stirring the basket 300, the waste material 10 does not overlap and the surface of the waste material is exposed to the liquid nitrogen 20, and the resin filler 30 and the waste material 10 collide evenly. By the stirring of the basket 300, the liquid nitrogen 20 is also stirred at the same time, and the impact of the resin filler 30 on the waste material 10 becomes stronger and promotes peeling. The peeled adherend is mixed into the circulating liquid nitrogen 20, overflows from the immersion tank 200, flows into the storage tank 220, and is captured by the filter 231 of the storage tank 220.

  The control device stops the stirring at a predetermined time, raises the basket 300 from the immersion tank 200 by the elevator, and stops at a predetermined height position (S6, S7).

After leaving at room temperature for a predetermined time, the waste material 10 is manually removed from the basket 300. (S8)
The process ends as described above. In this method, since the liquid nitrogen 20 adhering to the waste material 10 is vaporized by being left at room temperature, a process such as washing with water is unnecessary. Further, since no alkaline solution is used, a neutralization step is not necessary.

  Although not included in the above processing flow, when the level meter 270 of the storage tank 220 detects the shortage of the liquid nitrogen 20 during the processing, the controller opens the liquid nitrogen replenishing valve 280 to replenish the liquid nitrogen 20. Also do things. In this embodiment, liquid nitrogen 20 is used as the liquefied gas. However, the present invention is not limited to this, and since brittleness is likely to occur at a low temperature of about −10 ° C. or less, any liquefied gas that liquefies below that temperature can be used. Good. However, it is better to avoid those that cause environmental destruction and those that are flammable.

  In order to evaluate the recovery method of the present invention, a comparison was made with the case where the resin base material recovery apparatus 100 described above was used for processing by another method. There are four processing methods as follows.

(1) Liquid nitrogen immersion (PC resin filler) ... Method of the present invention (2) Liquid nitrogen immersion (alumina filler) ... Comparative Example 1
(3) Liquid nitrogen immersion (no filler) ... Comparative Example 2
(4) Immersion in alkaline solution: Comparative Example 3
In Comparative Example 1, 1 μm alumina filler was added to liquid nitrogen. The comparative example 2 is a thing without a filler. Conditions such as stirring and processing time in Comparative Example 1 and Comparative Example 2 are the same as those in the above-described processing flow. Comparative Example 1 and Comparative Example 2 are for comparing the effects of the PC resin filler of the present invention. Further, Comparative Example 3 is a method in which 1.2 atm is applied to a 10% aqueous solution of caustic soda at 80 ° C. for 1 H, and then washed with water. Comparison between a generally performed method and the method of the present invention is performed. It is for doing.

  The results are shown in FIG. The processing results in FIG. 5 show the peeled state of the recovered resin base material by visual observation and the dissolved state when the recovered resin base material is poured into dichloromethane and dissolved. First, in the method according to the present invention (immersion in liquid nitrogen, PC resin filler), there is no unpeeled disk and the film is peeled well. There was no undissolved material. Although peeling of Comparative Example 1 (liquid nitrogen immersion, alumina filler) was also good, cutting flaws were seen on the PC resin substrate, and the resin substrate was scraped with the alumina filler. Moreover, although the undissolved substance was not seen, the alumina filler was mixed in dissolved resin. In Comparative Example 2 (immersion in liquid nitrogen, no filler), there was an unpeeled disc and a film-like undissolved material was observed. Undissolved material is considered to be a printed film. In Comparative Example 3 (alkaline solution immersion), peeling was good and there was no undissolved material as in the method of the present invention.

  From the above results, it can be confirmed that the PC resin filler of the present invention has the same effect as that of alumina in the separation and separation of the adherend, and it is understood that they are insufficient without the filler. Moreover, it was confirmed that the same peeling can be performed as compared with the method of immersing in an alkaline solution which is generally performed.

  Next, in order to examine the quality of the recovered PC resin base material, the melt fluidity (melt volume rate: MVR) was measured. Again, in order to compare with the method according to the present invention, the alkaline solution immersion method and the virgin PC resin were measured together. FIG. 6 shows the measurement results. As shown in FIG. 6, the MVR value of the PC resin recovered by the method of the present invention is 62.0 cm 3/10 min, the method by immersion in an alkaline solution is 59.2 cm 3/10 min, and the virgin PC resin is 62.1 cm 3/10 min. showed that. That is, it was confirmed that the PC resin recovered by the method of the present invention is equivalent to the virgin PC resin and there is almost no decrease in the amount of fractionation. Moreover, in the method by immersion in an alkaline solution, it was found that the subtraction amount was reduced and deterioration was caused.

  As mentioned above, although the structural example of the resin base material collection | recovery apparatus 100 and the processing method example by the resin base material collection | recovery apparatus 100 were demonstrated, the above-mentioned Example is not limited to this, In the range which does not deviate from the summary of this invention It can be implemented in various ways.

DESCRIPTION OF SYMBOLS 10 Waste material 20 Liquid nitrogen 30 PC resin filler 100 Resin base material collection apparatus 200 Immersion tank 210 Overflow receiver 220 Storage tank 230 Outlet 231 Filter 240 Circulator 250 Inlet 260 Cover 270 Level meter 280 Liquid nitrogen replenishment valve 300 Basket 301 Wire rod 302 Protrusion Things 310 Stirrer 320 Elevator connection part 400 Hopper

Claims (9)

Add particulate material to the liquefied gas that liquefies below a predetermined liquefaction temperature,
A resin base material with an adherend on the surface is immersed in the liquefied gas, the liquefied gas is flowed, and the granular material added to the liquefied gas is caused to collide with the resin base material to thereby adhere the adherend. A resin substrate recovery method characterized by peeling. The granular material is a filler of the same material as the resin base material,
The method for recovering a resin base material according to claim 1. The method for recovering a resin substrate according to claim 1 or 2, wherein the liquefied gas is liquid nitrogen. The liquefied gas is circulated, the peeled adherend is mixed into the liquefied gas and transported to a predetermined position, and the peeled adherend is separated from the resin base material. 4. The resin substrate recovery method according to 3. The resin base material recovery method according to claim 1, wherein the waste material is placed in a net-like basket and immersed in the liquefied gas, and the basket is swung to prevent the waste material from overlapping. An immersion tank for storing a liquefied gas that liquefies below a predetermined liquefaction temperature;
A circulator for connecting the immersion tank and circulating the liquefied gas;
A hopper for charging granular material into the immersion bath;
A net-like basket containing a resin base material with an adherend on the surface;
A resin base material recovery apparatus, comprising: an elevating mechanism that elevates and swings the basket. The immersion tank includes a supply port that supplies the liquefied gas to a lower part of the immersion tank and an overflow receiver from which the liquefied gas flows out to an upper part, and the supply port and the overflow receiver are connected to the circulator. The liquefied gas is circulated. The resin base material recovery apparatus according to claim 6. The resin circulator according to claim 7, wherein the circulator further includes a storage tank, and the storage tank includes a filter that captures the adherend mixed in the liquefied gas. The resin base material recovery apparatus according to any one of claims 6 to 8, wherein the basket has a protrusion protruding on an inner surface.