JP2966104B2 - Resin recovery method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for recovering a resin from a resin plate. More specifically, the present invention relates to a method for selectively recovering a resin component from a resin plate having at least one surface coated with a metal thin film layer, a print coating layer, or both of them.

Background Art Conventionally, a method of detecting fine irregularities provided on a disk substrate by a laser beam to reproduce a sound or an image, a method of recording / reproducing information by an information recording layer provided on a substrate surface,
Also, various information recording media such as a system capable of erasing or overwriting recorded information have been developed and marketed. Such an information recording medium is required to have an extremely high storage capacity and an extremely high quality, so that even if it has minute defects, it must be a defective product. In addition, a large number of test samples must be taken from various parts of the production process to maintain high quality. In particular, compact discs exclusively for playback are produced in large quantities,
There is a problem in treating a large number of resin plates such as defective products and products collected from the market.

Conventionally, such recording media have been manufactured from a transparent resin such as a polycarbonate resin, a polymethyl methacrylate resin, and an amorphous polyolefin resin. Among them, the polycarbonate resin is used for compact discs, and large-scale production is performed. Samples, defective products, etc. occur simultaneously. For processing of these samples and defective products, the transparent optical substrate before applying the information recording layer and reflective layer is directly pulverized or repelletized, mixed with general polycarbonate resin and alloy with other resins, and reused without problems it can. However, the reuse of a resin plate provided with an information recording layer and a reflective layer and further provided with a protective coat layer such as a UV coat (hereinafter sometimes referred to as a “coated resin plate”) is significantly restricted. In addition, since the UV-coated layer of the UV-coated resin plate is incompatible with the polycarbonate resin, irregularities appear on the surface of the molded product obtained by simply mixing it with a general polycarbonate resin so that the appearance is significantly impaired. Become.

Therefore, it has been proposed to remove the information recording layer, the reflective layer and the protective coat layer from the resin plate and recover the resin itself.

 Some of the proposals are described below.

(I) JP-A-4-305414 (European Patent No. 476,475)
No. 5,151,452), JP-A-5-200379 (European Patent No. 537,567, U.S. Pat.No. 5,214,072) and JP-A-6-223416 (European Patent No. 601,719,
In these methods, the coated resin plate is chemically treated with, for example, an aqueous solution of an acid or an alkali. In other words, these methods are methods for removing the UV coat layer or the label print layer by dissolving the metal part of the information recording layer or the reflective layer, and the part without the metal part, the coat test,
It has the drawback that it is not possible to remove layers such as defective resin plates subjected to label printing tests, etc. In addition, it requires a neutralization treatment after treatment and a neutralization step of wastewater, so running costs were inevitable. .

(Ii) JP-A-5-345321: This method is a method in which the coated resin plate is immersed in hot water for a long time, and is excellent in that the above-mentioned method does not require the neutralization treatment. However, since this method is immersed in hot water for a long time, the polycarbonate resin substrate has a drawback that the molecular weight is reduced and whitening is apt to occur.

(Iii) JP-A-5-210873 and US Pat. No. 5,20
No. 3,067: These methods are methods in which the surface of the coating layer of the coated resin plate is mechanically cut and polished with a blade or an abrasive to remove it. These methods require a device for reading the cut surface or a device for reversing the surface of the resin plate, so the initial investment amount is large, and there are disadvantages such as a decrease in the resin recovery rate due to cutting, and it is difficult to spread the method. there were.

Problems to be Solved by the Invention The method for recovering resin from the coated resin plate described above,
The method is not economically and industrially satisfactory, and furthermore, it is difficult to understand the quality and the recovery rate from the viewpoint of reusing the resin. The conventional method has been inadequate especially when the resin molded product to be reused requires transparency and high quality.

None of these conventionally proposed methods are practical, and as a result, most of the resin plate obtained by sampling, the resin plate as a defective product, and the recovered resin plate are treated as industrial waste. This is a major problem when considering the increase in the number of recording media. In particular, it is a serious problem from the viewpoint of effective activity of resources and global environmental protection.

Accordingly, a first object of the present invention is to provide an industrially advantageous method capable of effectively removing a coating layer from a coated transparent resin plate and selectively recovering a resin component.

A second object of the present invention is to provide a method capable of recovering from a coated transparent resin plate without substantially deteriorating the quality of the resin and without including a coating layer substantially. is there.

A third object of the present invention is to provide a method for separating a resin component and a coating layer component from a coated transparent resin plate by a method that does not cause pollution and is useful for environmental protection.

It is another object of the present invention to provide a method for recovering a resin from a coated transparent resin plate and reusing the resin.

Means for Solving the Problems According to the study of the present inventors, the object of the present invention is to provide a metal thin film layer, a print coating layer or a metal thin film on at least one surface of a water-swellable transparent resin substrate. In recovering the resin from the resin plate coated with the layer with the print coating film, the following steps (a) a step of rolling the resin plate by passing the resin plate between at least one pair of rollers (Step A); b) a step of bringing the resin plate obtained in the preceding step A into contact with heated water or steam to swell the resin (step B); and (c) at least one of the swelled resin plate obtained in the preceding step B is obtained. Pressurizing the resin plate by passing between two paired rollers (step C); (d) contacting the resin plate thus obtained with flowing hot water (step D); and (e) coating. The resin plate from which the layer was peeled off The step of releasing (E
It has been found that this is achieved by a method for recovering resin from the resin plate comprising the following steps:

 Hereinafter, the method of the present invention will be described in more detail.

The resin plate targeted in the present invention is a substrate made of a transparent resin that is water-swellable and has a coating layer on one or both surfaces thereof. As previously mentioned,
The resin having the coating layer may be obtained as a sample for inspection or a defective product in the manufacturing process, or may be collected as a product. Further, a resin plate having no coating layer may be mixed as a part.

The water swellability of the resin is expressed as a water absorption of 0.05% by weight or more,
Preferably, it is at least 0.08% by weight for carrying out the method of the present invention. The thickness of the resin plate is not particularly limited as long as it is generally used as a recording medium, but is generally in the range of 0.5 to 3 mm, preferably 0.6 to 2 mm. The shape of the resin plate is a disk-shaped flat plate, and can be directly used in the recovery method of the present invention.

On the surface of the resin plate used as a recording medium, usually a thin metal film, for example, aluminum, Te, Fe, Co, Gd, SiN, Z
nS-SiO _2, GeSbTe, include ZnS and aluminum alloy, aluminum is suitable. Further, the thin film can be formed by means such as sputtering and vapor deposition.
Generally, this metal thin film is 0.4 to 2 μm, and the surface of the metal thin film is covered with a protective film. This protective film is
Usually, UV coating film of acrylic resin is used, 5 to 10μ
m.

Further, a printed layer is formed on the resin plate directly or on the metal film. This printing layer is also commonly referred to as label printing, and the printing layer generally has a thickness of 5 to 30 μm, preferably 10 to 25 μm. As a coating film for forming the print layer, for example, an acrylic paint, an acrylic-vinyl paint, a vinyl paint, a polyester paint, a melamine paint, an epoxy paint, and a urethane paint are used.

In the present invention, as described above, the metal thin film layer (including the protective coating layer thereon), the print coating layer, or the layer of the metal thin film layer and the print coating layer is formed and covered on the resin plate. Are collected. According to the present invention, the resin plate can be selectively recovered by substantially removing the coating layer from such a coated resin plate.

Specific examples of the coated resin plate include a ROM disk such as a compact disk, a mini disk, and a laser disk for a read-only type, and a CD-R and a write-once disk for a recording and reproduction type. E-DRAW such as magneto-optical disk, phase change optical disk, etc.
Optical disk. The material constituting the substrate of the resin plate may be a transparent resin. Usually, polycarbonate resin, polymethyl methacrylate resin, non-crystalline polyolefin resin and the like are used. Among them, a polycarbonate resin or a polymethyl methacrylate resin is preferable, and a polycarbonate resin is most preferable.

Such a polycarbonate resin may be one which is usually used as a thermoplastic aromatic polycarbonate resin molded article, and is generally produced by reacting a dihydric phenol with a carbonate precursor by a solution method or a melting method,
Those obtained by either method can be used in the same manner.

Representative examples of dihydric phenols used in the production of the aromatic polycarbonate resin include hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, bis (4-hydroxyphenyl) methane, 1,1-bis- ( 4-hydroxyphenyl) ethane, 2,2-bis-
(4-hydroxyphenyl) propane [commonly known as bisphenol A], 2,4-bis- (4-hydroxyphenyl)-
2-methylbutane, 1,1-bis- (4-hydroxyphenyl) -cyclohexane, 1,1-bis- (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane,
α, α′-bis- (4-hydroxyphenyl) -o-diisopropylbenzene, α, α′-bis- (4-hydroxyphenyl) -m-diisopropylbenzene, α, α
α'-bis- (4-hydroxyphenyl) -p-diisopropylbenzene, 2,2-bis- (3-methyl-4-hydroxyphenyl) -propane, 2,2-bis- (3-chloro-4-hydroxy Phenyl) -propane, bis-
(3,5-dimethyl-4-hydroxyphenyl) -methane, 2,2-bis- (3,5-dimethyl-4-hydroxyphenyl) -propane, 2,4-bis- (3,5-dimethyl-4 −
(Hydroxyphenyl) -2-methylbutane, 1,1-bis- (3,5-dimethyl-4-hydroxyphenyl) -siloxane, 1,1-bis- (3,5-dimethyl-4-hydroxyphenyl) -3, 3,5-trimethylcyclohexane,
α, α′-bis- (3,5-dimethyl-4-hydroxyphenyl) -o-diisopropylbenzene, α, α′-bis- (3,5-dimethyl-4-hydroxyphenyl) -m
-Diisopropylbenzene, α, α'-bis- (3,5-
Dimethyl-4-hydroxyphenyl) -p-diisopropylbenzene, 2,2-bis- (3,5-dichloro-4-hydroxyphenyl) -propane, 2,2-bis- (3,5-dibromo-4-hydroxy Phenyl) -propane, bis-
(4-hydroxyphenyl) -sulfone, bis- (4-
(Hydroxyphenyl) -sulfide, bis- (4-hydroxyphenyl) -ether, bis- (4-hydroxyphenyl) -ketone, bis- (4-hydroxyphenyl) -sulfoxide, and the like, alone or in combination of two or more. Can be used in combination.

Among them, a homopolymer of bisphenol A, bisphenol A, 1,1-bis- (4-hydroxyphenyl) -cyclohexane, 1,1-bis- (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, α , Α'-
Bis- (4-hydroxyphenyl) -m-diisopropylbenzene, 2,2-bis- (3-methyl-4-hydroxyphenyl) -propane, 2,2-bis- (3,5-dimethyl-4-hydroxyphenyl ) -Propane, 2,2-bis-
Copolymer obtained from at least two or more bisphenols selected from (3,5-dichloro-4-hydroxyphenyl) -propane and 2,2-bis- (3,5-dibromo-4-hydroxyphenyl) -propane Merging, especially 1,1-bis- (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane and bisphenol A, α, α'-bis-
A copolymer with (4-hydroxyphenyl) -m-diisopropylbenzene or 2,2-bis- (3-methyl-4-hydroxyphenyl) -propane is preferably used.

Examples of the carbonate precursor include carbonyl halide, diaryl carbonate, and haloformate. Specific examples include phosgene, diphenyl carbonate, dihaloformate of dihydric phenol, and a mixture thereof. In producing the polycarbonate resin, an appropriate molecular weight regulator, a branching agent, a catalyst for accelerating the reaction and the like can be used according to a usual method. 2 of the aromatic polycarbonate resin thus obtained
Mixing more than seeds is acceptable.

In the present invention, the coated layer can be separated from the resin plate by the following steps A to E of the coated resin plate as it is, and the resin can be isolated and recovered.

 Hereinafter, each step will be described.

Step A: This step is a step of rolling the coated resin plate by passing it between at least one pair of rollers. In this rolling step, the length rolled by the roller of the resin plate is 1.05 to 2 times the original length, preferably
Rolled to 1.1-1.8 times. The gap between the pair of rollers is about 0.6 to about 0.95 times, preferably about 0.7 to about 0.9 times the original thickness of the resin plate so that the resin plate is rolled in the above range.
Preferably, the gap is 0.9 times. At this time, it is desirable that the temperature of the roller is maintained at a temperature of 30 to 150 ° C, preferably 60 to 140 ° C. The number of rollers may be one or two or three. It can be passed several times using a pair of rollers.

The rotation directions of the pair of rollers are usually different from each other, and the two rollers may be rotating at the same circumferential speed or may have a difference in circumferential speed. In this case, the difference between the circumferential velocities may be such that the ratio of the circumferential velocities with the higher speed to the circumferential velocities with the lower speed is about 1.05 to 2 times.
However, the difference between the circumferential speeds of the pair of rollers in the step A of the present invention is not particularly necessary, and may be substantially the same.
However, if the circumferential speed of the pair of rollers is made different, shearing is more likely to occur, which may be advantageous. Although there is no particular limitation, when the gap between the opposed rollers is 0.9 mm, the difference in peripheral speed is preferably 1 cm / sec or more. Particularly preferred is 3 to 10 cm / sec, and 15 cm
If it exceeds / sec, an extreme warp phenomenon occurs, and subsequent handling becomes difficult, which is not preferable. It is advantageous that the number of times of rolling is large, but in most cases, a sufficient effect can be obtained by rolling several times, but the rolling direction is not limited to a single direction, and it is advantageous that rolling in multiple directions is easy to peel. . Further, heating the roller to keep the surface temperature below the glass transition temperature of the resin is advantageous in that the pressure during rolling is reduced and the mechanical life is extended.

The roller to be used may be any roller that is used industrially. Basically, no special roller is required as long as it is made of a material that is harder than a resin plate and does not cause deformation. For example, steel, plated steel, stainless steel and the like can be mentioned. Among them, stainless steel is preferable in terms of rust prevention.

The surface of the roller may be mirror-finished, pear-finished, or may have other irregularities, but a mirror-finished surface is usually used.

In the step A, it is necessary to roll the resin plate and roll it in its length direction, and it is not particularly necessary to apply stress to the surface of the resin plate, particularly to the coating layer and the resin plate.

Step B: The resin plate obtained in the step A (hereinafter sometimes referred to as “rolled resin plate”) is brought into contact with heated water or steam to absorb water and swell the resin. This B step does not require a special device or chemical, and a container (or a tank) of an appropriate size is used. When heated water is used, the rolled resin plate may be immersed in a container. Further, a method of spraying heated water or steam on the resin plate may be used. The degree of immersion is not particularly limited.
It is important that there is a difference in the degree of swelling of water with the applied coating layer. At this time, increasing the water temperature is advantageous because the immersion treatment can be completed in a short time, and it is meaningless to immerse at an unlimitedly high temperature or for a long time. The glass transition temperature of the resin plate or less is preferable in the sense of avoiding fusion and the like,
The immersion time is preferably within 30 minutes. A temperature of 50-120 ° C, preferably 70-95 ° C, 2-20 minutes is practical.

The water used for swelling the resin in the step B may be water vapor. Water may contain 20% by weight or less, preferably 10% by weight or less, of another solvent that does not dissolve the resin and is soluble in water. Such other solvents include, for example, alcohols, glycols and ketones, and when the transparent resin is an aromatic polycarbonate resin, alcohol is preferred.

In the step B, a part of the coating layer may peel off from the resin plate. In that case, the separated pieces of the coating layer may be removed by an operation such as washing with water. In addition, when the swelling operation is performed in heated water, the stripped coating layer pieces can be removed only by removing the rolled resin from the container.

The resin plate from which a part of the coating layer has been peeled off or has become easily peeled off is sent to the next step C.

Step C: The step C is a step of applying pressure by passing the swollen resin plate having passed through the step B through at least one pair of rollers. The coating layer that has been easily peeled off by this step can be completely separated from the resin plate in the next step D.

The pressurization in the step C is performed by passing the swollen resin plate between at least one pair of rollers. At this time, the same type of roller as described in the step A can be used as the pair of rollers.

In the step C, the resin plate is pressed and compressed by the pair of rollers. The compression ratio is suitably in the range of 5 to 50%, preferably 10 to 30%. Here, compression ratio (%)
Is represented by the following equation.

If the compression ratio exceeds 50%, the resin plate may be undesirably cracked.

Each time the resin plate is pressed at the compression ratio, the swollen resin plate is further rolled. This C step is advantageously performed so that the resin plate is rolled 1.01 to 1.5 times, preferably 1.02 to 1.4 times the length in the rolling direction before and after the C step. It is also possible to carry out the pressurization once or pressurize by a plurality of pairs of rollers. In this case, the pair of rollers to be used, the rotation conditions thereof, and the circumferential speed difference are substantially the same as those described in the step A. However, if the circumferential speed difference is too large, for example, if it exceeds 15 cm / sec, the warpage of the resin plate becomes large, which is not desirable. Usually, the pair of rollers is implemented with the same circumferential speed or with a slight speed difference. The roller temperature is suitably in the range of 30 to 140 ° C., preferably 60 to 130 °.

Step D: The resin plate obtained in the step C is in a state where the coating layer is partially peeled off or extremely easily peeled off. In the step D, the coating layer can be almost completely peeled off by coming into contact with the heated water flowing through the resin plate from the step C. The step D does not require a special device like the step B and can be performed in a simple vessel. For example, a resin plate and heated water may be put in a container and stirred.
Further, the heating can be performed by spraying heated water onto the resin plate by a shower.

In step D, the temperature of the heating water is suitably from 70 to 120 ° C, preferably from 85 to 95 ° C, and the contact time is preferably 60 minutes or less, and usually 15 to 30 minutes is practical.

Step E: The coating layer is almost completely peeled off from the resin plate in the form of small pieces by the step D, and a transparent resin plate is obtained.
In the step D, the coating layer formed into small strips is dispersed in heated water, so the resin plate is separated, and if necessary, a simple washing with water is performed to remove the coating layer from the transparent resin. You can get a board. The obtained resin plate is dried and collected.

As described above, the resin recovered from the steps A to E of the present invention is transparent and slightly rolled as compared with the plate-like form before the treatment, but retains substantially the same form.
When the compact disc is processed according to the invention, a transparent oval resin plate is recovered.

The resin plate recovered by the present invention does not contain a coating layer, is transparent, has almost no quality deterioration, and can be melted and reused as it is. Further, it can be used by mixing with the same kind of resin, or can be used by blending with another resin. For example, in the case of a polycarbonate resin plate, the recovered resin plate can be reused as it is or mixed with the same polycarbonate resin or another polycarbonate resin of a different type and reused as a molded product. In addition, a molded article can be obtained by mixing with an ABS resin or a polyester resin for reuse.

Examples Hereinafter, the present invention will be further described with reference to Examples. The evaluation items and the measurement method were as follows.

(1) Peeling state: The degree of peeling of the rolled resin sheet after the finishing step (step E) of removing and washing the remaining coating layer was visually evaluated in three stages, and peeling state 3 was regarded as acceptable.

Peeled state = 3: State in which all coating layers are peeled Peeled state = 2: State in which non-peeled coating layer remains partially or in dots, or part of a multilayer coating layer remains on the entire surface Peeling state = 1: The state in which the coating layer has not been peeled off at all (2) Appearance of molded article: The presence or absence of foreign matter was visually confirmed.

(3) Impact value: Izod impact value with V notch
Measured according to ASTM D256 on 8 inch specimens.

(4) Average molecular weight: The viscosity average molecular weight (M) of the polycarbonate resin was determined using Huggin using methylene chloride as a solvent.
Equation of s (ηsp / c = [η] + k ′ [η] ² c, k ′ = 0.45)
The intrinsic viscosity [η] is determined by the following formula, and Schnell's formula ([η] =
1.23 × 10 ⁻⁴ M ^0.83 ).

(5) Water absorption: A square plate having a side of 50 ± 1 mm and a thickness of 3 ± 0.2 mm was condition-adjusted, dried in a thermostat kept at 50 ° C. for 24 hours, and allowed to cool in a desiccator. The test piece was immersed in an immersion liquid (new distilled water) at 20 ° C. for 24 hours, and the change in weight was measured to determine the water absorption.

Example 1 A polycarbonate resin substrate (1.2 mm) having a viscosity average molecular weight of 15,100 and a water absorption of 0.20% by weight / aluminum vapor deposition layer (1 μm)
m) / UV coating layer (5-10 μm) / label printing layer (20
μm), the gap between the rolls facing the resin plate A is
0.9 mm, surface temperature set at 110 ° C, manufactured by Otake Mechanism Co., Ltd. 2
Pre-rolling (process A) was performed by this roll machine. The rolling conditions at this time were as follows: roll rotation speed = high-speed side 16 rpm, low-speed side 14 rpm, roll diameter = 12 inches, roll width = 24 inches. The rolling ratio of the rolled disk was 1.25, and cracks occurred in the coating layer on the entire surface. Next, as a primary hot water treatment (Step B), the label printing layer and the protective coating layer are immersed in hot water for 5 minutes, and the label printing layer and the protective coating layer are separated and separated. Was removed. Further, in order to remove the remaining coating layer, the roll was rolled with the roll machine at a roll gap of 0.8 mm (process C). As a result, a resin plate having a compression ratio of 11% was obtained. Thereafter, as a secondary hot water treatment, the substrate was immersed in hot water of 95 ° C. with stirring for 30 minutes (Step D) to remove any remaining aluminum vapor-deposited layer. The rolled plate thus obtained was able to be recovered as a transparent polycarbonate resin after the final washing (step E), with almost no loss of the resin component.

The obtained rolled plate is pulverized into a 6 mmφ screen passing product using a pulverizer manufactured by Horai Co., Ltd., pelletized by a conventional method, dried at 120 ° C. for 5 hours, and tested at 270 ° C. by an injection molding machine manufactured by Nippon Steel Works. A piece was molded. No foreign matter was observed in the molded product, and no irregularities were observed on the surface. The impact value was 5 kgf · cm / cm, and the viscosity average molecular weight of the test piece was 15,000, which was almost equivalent to the initial polycarbonate resin.

Examples 2 to 6 The same procedures as in Example 1 were carried out except that the various resin plates shown in Table 1 were used and the resin recovered under the conditions shown in Table 1 was used.
It was shown to.

The configuration of the resin plate used in Tables 1 to 3 is as follows.

Resin plate A: Substrate / aluminum deposition layer / UV coating layer / label printing layer Resin plate B: Label printing layer / substrate / label printing layer Resin plate C: Substrate / label printing layer Resin plate D: Label printing layer / substrate / aluminum Deposition layer / UV coating layer / Label printing layer Resin plate E: Substrate / Aluminum deposition layer / UV coating layer Resin plate F: Substrate / Aluminum deposition layer / UV coating layer / Label printing layer Here, substrates of resin plates A to E Is thickness 1.2mm, water absorption 0.2
A substrate made of an aromatic polycarbonate resin (AD-5503, manufactured by Teijin Chemicals Limited) having a weight-average molecular weight of 15,100 and a weight of aluminum deposited layer of 1 μm, thickness of a UV coating layer (protective coating layer) Is 5-10 μm, and the thickness of the label printing layer is
20 μm.

The substrate of the resin plate F is a substrate made of a copolymerized polycarbonate resin having a viscosity-average molecular weight of 14,700 and a water absorption of 0.19% by weight. In this copolymerized polycarbonate, the dihydric phenol component is bisphenol A and 1,1-bis (4- 70:30 for (hydroxyphenyl) -3,3,5-trimethylcyclohexane
(Mol%) of the copolymer.

Examples 7 to 10 A calender roll machine (roll diameter = 420 mm) made by Yuri Roll Machine Co., Ltd. of constant speed rotation was used as a rolling roll machine, and the roll peripheral speed was arbitrarily selected from the range of 5.3 to 15.8 cm / sec.
The test was carried out in the same manner as in Example 1 under the conditions shown in Table 2 using the above various resin plates.

Comparative Examples 1 to 3 The conditions were changed as shown in Table 3, and the waste disk was directly crushed, immersed in hot water or rolled, and injection molded in the same manner as in Example 1 to obtain a test piece. The results are shown in Table 3.

Advantageous Effects of the Invention According to the present invention, it is possible to easily and transparently recover and reuse a transparent resin from a resin plate which has been treated as industrial waste with almost no value, and the development of the optical recording medium industry It greatly contributes to the recycling of resources from environmental protection and the global environment, and is extremely effective industrially. Moreover, the process is simple, there is no pollution, and it is industrially advantageous.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-52-49281 (JP, A) JP-A-5-208419 (JP, A) JP-A-56-98134 (JP, A) (58) Survey Field (Int.Cl. ⁶ , DB name) B29B 7/00-17/02

Claims (12)

(57) [Claims] 1. A method for recovering a resin from a resin plate in which at least one surface of a water-swellable transparent resin substrate is coated with a metal thin film layer, a printed coating layer or a layer of a metal thin film and a printed coating film. (A) a step of rolling the resin plate by passing the resin plate between at least one pair of rollers (step A); and (b) heating the resin plate obtained in step A with heated water or steam. (B) a step of contacting and swelling the resin, and (c) a step of pressing the resin plate by passing the swollen resin plate obtained in the preceding step B between at least one pair of rollers ( C), (d) contacting the resin plate thus obtained with flowing hot water (D) and (e) separating the resin plate from which the coated layer has been peeled (E).
A method for recovering resin from the resin plate, comprising: 2. The method according to claim 1, wherein in step A, the resin plate is rolled at a rolling ratio of 1.05 to 2 times. 3. The method according to claim 1, wherein in step A, the resin plate is rolled by a pair of rollers having a temperature of 30 to 150 ° C. 4. The method according to claim 1, wherein in step B, water or steam heated to a temperature of 50 to 120 ° C. is brought into contact. 5. The method according to claim 1, wherein in step C, the swollen resin plate is pressurized by passing between a pair of rollers having a gap of 0.6 to 0.95 times the thickness. 6. The method according to claim 1, wherein in step C, the resin plate is pressed by passing between a pair of rollers having a temperature of 30 to 140 ° C. 7. The method according to claim 1, wherein in step D, the resin plate is brought into contact with water having a temperature of 70 to 120 ° C. 8. The recovery method according to claim 1, wherein the water-swellable transparent resin is a resin having a water absorption of 0.08% by weight or more. 9. The method according to claim 1, wherein the water-swellable transparent resin is an aromatic polycarbonate resin or a polymethyl methacrylate resin. 10. The method according to claim 1, wherein the water-swellable transparent resin is an aromatic polycarbonate resin. 11. The recovery method according to claim 1, wherein the resin plate to be treated has at least one surface of a resin substrate covered with a metal thin film layer / printed coating layer. 12. A method for regenerating a resin from a resin plate, wherein the resin plate obtained by the recovery method according to claim 1 is melt-molded as it is or mixed with a new same resin or another resin. .