JP2001342290A - Method for decomposing thermosetting resin and apparatus for decomposition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide both a method for decomposition and an apparatus for decomposition by which the method is suitable for recycling a thermosetting resin that provides an insoluble and infusible solid after curing, is not easily subjected to chemical cycling and requires treatment at high temperatures for long time or at high temperatures under high pressures and the thermosetting resin is converted into a liquid decomposition product by treatment at a low temperature in a short time. SOLUTION: This method for decomposing the thermosetting resin comprises dipping the thermosetting resin in a solvent containing a gas dissolved therein and irradiating the thermosetting resin dipped in the solvent with ultrasonic waves and, as necessary, adding a decomposition catalyst to the solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the treatment of thermosetting resins contained in wastes and the like. More specifically, the present invention relates to a method and an apparatus for decomposing a thermosetting resin by chemical treatment.

[0002]

2. Description of the Related Art Thermosetting resins have been widely used in various applications because of their excellent mechanical properties, heat resistance, flame retardancy, chemical resistance and the like. The thermosetting resin is used not only as a single resin depending on the application, but also as a composite containing a filler or as a foam containing bubbles inside.

A thermosetting resin generally forms a three-dimensional crosslinked structure after curing and becomes an insoluble and infusible solid, so that it is difficult to perform a decomposition treatment. For this reason, thermosetting resins are considered to be unsuitable for recycling, and have conventionally been discarded by landfilling or the like.

However, in recent years, decomposition and recycling of waste resin has become an important problem due to an increase in waste and a shortage of waste treatment facilities. Thermosetting resin is used for house building materials,
It is often used for the production of large products such as lightweight structures, and there is a need for the development of recycling technologies for reducing the volume of waste thermosetting resins.

[0005] The forms of recycling include energy recycling for recovering and reusing thermal energy released by incineration of waste, material recycling using mechanically crushed waste as a structural material, and chemical recycling of waste. Of chemical recycling that converts into industrial materials that can be reused by chemical treatment, such as low-molecular substances that can be used as raw materials for resin
Can be roughly divided into two.

[0006] However, energy recycling is a low reuse method that can be performed only once. In material recycling, the degree of reuse is higher than energy recycling, but the performance of recycled products cannot be maintained higher than the original products. Later, it cannot be reused and must eventually be disposed of in landfills. On the other hand, chemical recycling is a method with a high degree of reuse because it is converted into a low-molecular substance or the like which is a raw material for resin synthesis.

[0007]

However, the thermosetting resin becomes an insoluble and infusible solid after curing, and has excellent properties such as high mechanical strength, high heat resistance, and chemical resistance. Making recycling difficult,
In the treatment of an organic solvent containing an acid or an alkali, there is a problem that a long time treatment at a high temperature is required. Further, the treatment with pressurized water requires a treatment at a high temperature and a high pressure, and there is a problem that a large-scale facility with safety measures is required.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem, and a thermosetting resin suitable for recycling can be obtained by a short-time chemical treatment that does not require a special high temperature and high pressure. An object of the present invention is to provide a method and an apparatus for decomposing a thermosetting resin that can be converted into decomposition products.

[0009]

A first method for decomposing a thermosetting resin according to the present invention comprises a step of immersing the thermosetting resin in a solvent, and a step of immersing the thermosetting resin in the solvent in an ultrasonic wave. Irradiation step.

In a second method for decomposing a thermosetting resin according to the present invention, in the first method for decomposing a thermosetting resin, the solvent contains a catalyst for accelerating the decomposition of the thermosetting resin. That is.

A third method for decomposing a thermosetting resin according to the present invention is that, in the first or second method for decomposing a thermosetting resin, the solvent is a solvent in which gas is dissolved in advance.

A fourth method for decomposing a thermosetting resin according to the present invention is the method for decomposing a thermosetting resin according to any one of the first to third aspects, wherein the frequency of the ultrasonic wave to be applied is 20 kHz or more and 1 MHz or less. That is.

A fifth method for decomposing a thermosetting resin according to the present invention is the method for decomposing a thermosetting resin according to any one of the first to fourth aspects, wherein the intensity of the ultrasonic wave to be applied is 1 W / cm ^2.
More than 500 W / cm ² .

A sixth method of decomposing a thermosetting resin according to the present invention is the method of decomposing a thermosetting resin according to any one of the first to fifth aspects, wherein the thermosetting resin comprises an ester bond, a urethane bond, and a urea. At least one type of bond is included.

A seventh method for decomposing a thermosetting resin according to the present invention is the method for decomposing a thermosetting resin according to any one of the first to fifth aspects, wherein the thermosetting resin is a polyurethane resin.

The first thermosetting resin decomposition apparatus according to the present invention comprises a means for immersing the thermosetting resin in a solvent, and a means for irradiating the thermosetting resin immersed in the solvent with ultrasonic waves. It is provided.

The thermosetting resin decomposing apparatus according to the second aspect of the present invention is the first thermosetting resin decomposing apparatus, wherein:
It is provided with means for dissolving gas in the solvent.

[0018]

Embodiment 1 FIG. 1 is a configuration diagram of a thermosetting resin decomposition apparatus according to Embodiment 1 of the present invention. In the figure, 1 is an ultrasonic generator, 2 is an ultrasonic vibrator, 3 is a temperature control medium flow path, 4 is a gas blowing pipe, 5 is a thermosetting resin inlet, 6 is a stirrer, 7 is a cooler, Reference numeral 8 denotes a decomposition tank, 9 denotes a solvent, and 10 denotes a thermosetting resin decomposition device.

The thermosetting resin decomposition apparatus 10 according to the first embodiment
Can store the solvent 9 for decomposing the thermosetting resin in the decomposition tank 8, and the solvent 9 stored in the decomposition layer 8
The medium is maintained at a predetermined temperature by circulating a medium at a predetermined temperature through the temperature control medium flow path 3 installed outside the device. Although not shown in the figure, the gas blowing pipe 4 is connected to a gas supply device, and blows gas into the solvent 9.
The gas is dissolved in the solvent 9. In the present embodiment, the number of the gas blowing pipes 4 is one, but a plurality may be provided. Also,
It is preferable to provide a plurality of gas blowing holes in the gas blowing pipe 4 because the gas dissolving efficiency in the solvent 9 is improved. In the present embodiment, the gas blowing pipe 4 is used to dissolve the gas in the solvent 9, but an air loading device may be used. The ultrasonic vibrator 2 is installed at the bottom of the decomposition tank 8, and receives a solvent 9 by a signal from the ultrasonic generator 1.
By irradiating the thermosetting resin immersed therein with ultrasonic waves, the thermosetting resin can be decomposed. In the present embodiment, the ultrasonic vibrator 2 is installed at the bottom of the decomposition tank 8. However, if ultrasonic waves can be applied to the thermosetting resin put into the decomposition tank 8, the installation position is limited to the bottom of the decomposition tank 8. It does not do. The stirrer 6 stirs the thermosetting resin together with the solvent 9 at the time of ultrasonic irradiation, and makes the irradiation of the ultrasonic waves to the thermosetting resin uniform,
Improves the decomposition efficiency of thermosetting resin. The cooler 7 prevents the pressure in the decomposition tank 8 from rising, and liquefies and traps the volatilized solvent 9 to return to the decomposition tank 8 to prevent the solvent 9 from being distilled.

Next, the method for decomposing the thermosetting resin of the present invention will be described with reference to FIG. First, a predetermined amount of the solvent 9 is stored in the decomposition tank 8 of the decomposition apparatus 10. At this time, a catalyst for promoting the decomposition of the thermosetting resin may be added as necessary. The catalyst is preferably added at a ratio of 0.1 parts by weight to 10 parts by weight with respect to 100 parts by weight of the solvent. Next, the heat medium is circulated through the flow path 3 of the temperature control medium, and the solvent 9 is set to a predetermined temperature equal to or lower than its boiling point. Next, the gas is dissolved in the solvent 9 by bubbling for blowing the gas into the solvent 9 from the gas blowing pipe 4. The amount of gas blown is preferably 0.1 cc to 10 cc per minute per 100 cc of the solvent. As a method for dissolving the gas in the solvent 9, an air loading method may be used. Next, a thermosetting resin to be decomposed into a solvent is injected through the resin injection hole 5. It is preferable to mechanically pulverize the injected thermosetting resin into small pieces, since the contact area with the solvent 9 is increased and the decomposition rate of the thermosetting resin is increased. The size of the thermosetting resin strip is, for example, 0.1 mm
~ 50 mm is preferred.

Next, the solvent 9 containing the thermosetting resin is stirred by the stirrer 6 to disperse the thermosetting resin in the solvent. Next, the distributed thermosetting resin in a solvent, from the ultrasonic oscillator 2, a frequency is at 20 kHz to 1 MHz, acoustic intensity ultrasonic irradiation of 1W / cm ² ~500W / cm ² for a predetermined time.
It is preferable to perform blowing of gas and stirring of the solvent even during the irradiation with the ultrasonic wave, since the decomposition efficiency of the thermosetting resin is improved. Further, even when the gas is not dissolved in the solvent 9 in advance,
Although the decomposition time is slightly longer, the thermosetting resin can be decomposed at a low temperature by ultrasonic irradiation.

The thermosetting resin used in the present embodiment includes epoxy resin, polyurethane resin, phenol resin, unsaturated polyester resin, urea resin, melamine resin, polyimide resin, silicone resin and the like.

The solvent 9 used in the present embodiment includes water and an organic solvent. In particular, when decomposing an epoxy resin, an unsaturated polyester resin, a polyurethane resin, a urea resin, a melamine resin which is a thermosetting resin having at least one bond of an ester bond, a urethane bond and a urea bond in a molecule. As the solvent 9, one having at least one hydroxyl group in the molecule as the solvent 9 is used. Specifically, water, alcohols such as methanol and ethanol,
Glycols such as ethylene glycol and propylene glycol, and polyols are exemplified.

The catalyst for accelerating the decomposition used as required in the present embodiment includes inorganic basic compounds such as hydroxides of alkali metals and hydroxides of alkaline earth metals, and organic compounds such as organic amine compounds. Examples include basic compounds, organic metal compounds such as dibutyltin dilaurate and dibutyltin diacetate, and acids such as sulfuric acid, hydrochloric acid, nitric acid, organic carboxylic acids, and hydrogen peroxide.

The gas dissolved in the solvent 9 used in the present embodiment may be any gas as long as it does not inhibit the decomposition reaction, and examples thereof include general-purpose gases such as air, nitrogen, oxygen, and helium.

Next, the action of the present invention for promoting the decomposition of the thermosetting resin by the irradiation of ultrasonic waves will be described. When a solvent is irradiated with ultrasonic waves, for example, as described in Kato et al.'S literature (Chemical Society of Japan 1998, No.8, page 530), bubbles are generated by dissolved gas in the solvent (cavitation).
Then, a high-temperature and high-pressure state (hot spot) is generated by the crushing, and the locally generated high-temperature and high-pressure reaction field accelerates the decomposition of the thermosetting resin.

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples.

[0028]

[Embodiment 1] As a thermosetting resin foam, 100 parts by weight of a polyol (hydroxyl value: 460 mg KOH / g), 3 parts by weight of an organic amine catalyst, 3 parts by weight of a silicone foam stabilizer, 12 parts by weight of cyclopentane, and 2 parts by weight of water And 160 parts by weight of polymeric diphenylmethane diisocyanate (amine equivalent: 135 g / equivalent) was mixed with the mixed solution previously added to obtain a polyurethane foam. This polyurethane foam was pulverized by a pulverizer to obtain a polyurethane foam powder having an average particle size of 1 mm or less.

Next, for example, 101 parts by weight of a solution obtained by dissolving 1 part by weight of potassium hydroxide as a decomposition catalyst in 100 parts by weight of dipropylene glycol as a solvent 9 in the decomposition tank 8 of the decomposition apparatus 10 shown in FIG. Input. Next, the solution was heated and maintained at 80 ° C.
Bubble air through the solution for 1 hour. afterwards,
100 parts by weight of the polyurethane foam powder was put into a solution having a liquid temperature of 80 ° C., and the solution was stirred at a frequency of 100 kHz.
The polyurethane foam powder is decomposed by irradiating an ultrasonic wave having a sound wave intensity of 1 W / cm ² . Since the polyurethane foam powder has a large bulk volume, depending on the size of the decomposition tank 8, not all of the powder may be put into the decomposition tank 8 at one time. good.
In this example, the decomposition was completed after 5 hours. When a polyurethane foam powder having a particle size smaller than that used in this example is used, the decomposition time can be further reduced. The decomposition product thus obtained has a hydroxyl value of 440 mgKOH /
g of the recycled polyol compound.

Embodiment 2 FIG. The addition amount of potassium hydroxide as a decomposition catalyst was 5 parts per 100 parts by weight of dipropylene glycol.
Decomposition treatment was performed in the same manner as in Example 1 except that the amount was changed to parts by weight. Potassium hydroxide did not completely dissolve in the solvent dipropylene glycol, potassium hydroxide remained undissolved, the decomposition was completed after 5 hours as in Example 1, and the decomposition product was a recycled polyol having a hydroxyl value of 440 mgKOH / g. Compound.

Embodiment 3 FIG. The decomposition treatment was performed in the same manner as in Example 1 except that 1 part by weight of triethylenediamine was added to 100 parts by weight of dipropylene glycol instead of potassium hydroxide as a decomposition catalyst. 4 which is shorter than Example 1
After a period of time, the decomposition is completed, and the decomposition product has a hydroxyl value of 440.
The regenerated polyol compound was mgKOH / g.

Embodiment 4 FIG. The decomposition treatment was performed in the same manner as in Example 3 except that the amount of triethylenediamine as the decomposition catalyst was changed to 5 parts by weight. With the increase in the amount of the cracking catalyst, the cracking was completed 2.5 hours later than in Example 3, and the cracked product was a regenerated polyol compound having a hydroxyl value of 440 mgKOH / g.

Comparative Example 1 The decomposition treatment was performed in the same manner as in Example 1 except that no ultrasonic wave was applied during the decomposition treatment.
Even after 24 hours from the start of the treatment, the charged polyurethane foam powder remained in a solid state, and the decomposition was not completed.

Comparative Example 2 The decomposition treatment was performed in the same manner as in Example 1 except that the solution temperature was set to 180 ° C. without irradiating ultrasonic waves during the decomposition treatment. The decomposition was completed after 8 hours, and
A similar decomposition product was obtained.

Comparative Example 3 The decomposition treatment was performed in the same manner as in Example 4, except that no ultrasonic wave was applied during the decomposition treatment.
Even after 24 hours from the start of the treatment, the charged polyurethane foam powder remained in a solid state, and the decomposition was not completed.

Comparative Example 4 The decomposition treatment was performed in the same manner as in Example 4 except that the solution temperature was set to 180 ° C. without irradiating ultrasonic waves during the decomposition treatment. Triethylenediamine vapor was generated, and even after 24 hours from the start of the treatment, the charged polyurethane foam powder remained in a solid state, and the decomposition was not completed.

Embodiment 5 FIG. As a thermosetting resin molding material, 17 parts by weight of a bisphenol-type epoxy compound, 15 parts by weight of a modified acid anhydride, and 68 parts by weight of silica powder were mixed,
It was cured by heating to prepare an epoxy resin plate-like molded product. This plate-like molded product is mechanically crushed, and the length in the longitudinal direction is 5 m.
m pieces were obtained.

Next, for example, 300 parts by weight of a 1 N aqueous potassium hydroxide solution is charged into the decomposition tank 8 of the decomposition apparatus 10 shown in FIG. Using an air pump, air is bubbled through the gas injection pipe 4 for 1 hour into the aqueous solution whose temperature has been adjusted to 25 ° C. Next, 200 parts by weight of the strip of the epoxy resin molded product is put into the decomposition tank 8 and stirred. Ultrasonic waves having a frequency of 100 kHz and a sound intensity of 1 W / cm ² were irradiated on the strips of the epoxy resin molded product dispersed in the aqueous solution to decompose the epoxy resin molded product. In this example, the decomposition was completed after 3 hours, and the liquid product and the silica powder could be recovered. If the epoxy resin molded product is sufficiently crushed and powdered, the decomposition time can be reduced.

Comparative Example 5 The decomposition process was performed in the same manner as in Example 5, except that no ultrasonic wave was applied during the decomposition process.
Even 3 hours after the start of the treatment, 90 wt% or more of the charged epoxy resin molded product remained in a solid state, and the progress of decomposition was extremely slow.

Embodiment 6 FIG. As a thermosetting resin molding material, 15.6 parts by weight of unsaturated polyester and 12.6 parts of styrene were used.
Parts by weight and tertiary butyl peroxybenzoate 0.3
Unsaturated polyester resin heat-cured by adding a filler composed of 57 parts by weight of calcium carbonate, 2 parts by weight of zinc stearate, 1 part by weight of magnesium oxide, and 10 parts by weight of glass fiber to a binder consisting of Was prepared. This plate-like molded product was mechanically crushed to obtain a strip having a longitudinal dimension of about 5 mm.

Next, for example, 140 parts by weight of N-methyl-2-pyrrolidone is placed in the decomposition tank 8 of the decomposition apparatus 10 shown in FIG.
A mixed solution comprising 50 parts by weight of ethanol and 10 parts by weight of triethylenediamine is charged. Air is bubbled through the gas injection pipe 4 for one hour using an air pump into the solution whose temperature has been adjusted to 25 ° C. Next, 100 parts by weight of the strip of the unsaturated polyester resin molded product is dropped into the solution and stirred. A strip of an unsaturated polyester resin molded product uniformly dispersed in a solution was applied at a frequency of 100 kHz and a sound intensity of 10 W / cm ^2.
Was irradiated to decompose the unsaturated polyester resin molded product. In this example, the decomposition was completed after 8 hours, and the liquid product and the filler powder could be recovered. When the unsaturated polyester resin molded product is sufficiently crushed and powdered, the decomposition time can be reduced.

Comparative Example 6 The decomposition process was performed in the same manner as in Example 6, except that no ultrasonic wave was applied during the decomposition process.
Even after 8 hours from the start of the treatment, the weight loss rate of the charged unsaturated polyester resin molded product was 3 wt% or less, and almost no decomposition occurred.

As shown in the above Examples and Comparative Examples,
In the method of decomposing a thermosetting resin in a solvent, irradiation with ultrasonic waves can shorten the decomposition time and significantly lower the decomposition temperature. In addition, the ultrasonic irradiation
Since the decomposition treatment temperature is lowered, an organic amine decomposition catalyst such as triethylenediamine, which cannot be used by vaporization and evaporation in the conventional high-temperature decomposition treatment, can be used. The decomposition catalyst of the organic amine has a high solubility in the solvent used at the time of decomposition, and the amount of addition can be increased, so that the decomposition time can be further shortened.

[0044]

The first method for decomposing a thermosetting resin according to the present invention comprises the steps of immersing the thermosetting resin in a solvent, and irradiating the thermosetting resin immersed in the solvent with ultrasonic waves. In the decomposition treatment of the thermosetting resin in a solvent, the decomposition time can be shortened and the decomposition temperature can be lowered.

The second method for decomposing a thermosetting resin according to the present invention is the same as the first method for decomposing a thermosetting resin, wherein the solvent contains a catalyst for accelerating the decomposition of the thermosetting resin. And the decomposition time can be further reduced.

A third method of decomposing a thermosetting resin according to the present invention is the method of decomposing the first or second thermosetting resin, wherein the solvent is a solvent in which gas is dissolved in advance. Improves the decomposition efficiency of thermosetting resin by ultrasonic irradiation.

The fourth method for decomposing a thermosetting resin according to the present invention is the method for decomposing a thermosetting resin according to any one of the first to third aspects, wherein the frequency of the ultrasonic wave to be applied is 20 kHz or more and 1 MHz or less. And the decomposition efficiency of the thermosetting resin is excellent.

The fifth method for decomposing a thermosetting resin according to the present invention is the method for decomposing a thermosetting resin according to any one of the first to fourth aspects, wherein the intensity of the ultrasonic wave applied is 1 W / cm ^2.
It is 500 W / cm ² or less, and the decomposition efficiency of the thermosetting resin is good.

A sixth method for decomposing a thermosetting resin according to the present invention is the method for decomposing a thermosetting resin according to any one of the first to fifth aspects, wherein the thermosetting resin comprises an ester bond, a urethane bond, a urea Including at least one kind of bond among the bonds, and the decomposition is easily caused.

A seventh method for decomposing a thermosetting resin according to the present invention is the method for decomposing a thermosetting resin according to any one of the first to fifth aspects, wherein the thermosetting resin is a polyurethane resin. Great effect of volume reduction of waste.

The first thermosetting resin decomposition apparatus according to the present invention comprises a means for immersing the thermosetting resin in a solvent and a means for irradiating the thermosetting resin immersed in the solvent with ultrasonic waves. The thermosetting resin can be decomposed at a low temperature in a short time.

The apparatus for decomposing a thermosetting resin for a second minute according to the present invention is the same as the first apparatus for decomposing a thermosetting resin,
This is provided with means for dissolving gas in the solvent, and can improve the decomposition efficiency of the thermosetting resin.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a thermosetting resin decomposition device according to Embodiment 1 of the present invention.

[Explanation of symbols]

1 Ultrasonic generator, 2 Ultrasonic vibrator, 3 Temperature control medium flow path, 4 Gas blowing pipe, 5 Thermosetting resin inlet, 6 Stirrer, 7 Cooler, 8 Decomposition tank, 9 Solvent, 1
0 Thermosetting resin decomposition equipment.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F301 AA22 AA23 AA24 AA25 AA27 AA29 CA09 CA12 CA22 CA23 CA43 CA51 CA61 CA71 4G069 AA06 BA21B BD06B BE15B CA04 CA10 DA02

Claims (9)

[Claims] A step of immersing the thermosetting resin in a solvent;
Irradiating the thermosetting resin immersed in the solvent with ultrasonic waves. 2. The method for decomposing a thermosetting resin according to claim 1, wherein the solvent contains a catalyst for promoting the decomposition of the thermosetting resin. 3. The method for decomposing a thermosetting resin according to claim 1, wherein the solvent is a solvent in which gas is dissolved in advance. 4. The frequency of the ultrasonic wave to be irradiated is 20 kHz or more and 1 MHz.
The method for decomposing a thermosetting resin according to any one of claims 1 to 3, wherein z is not more than z. 5. The method for decomposing a thermosetting resin according to claim 1, wherein the intensity of the ultrasonic wave to be applied is 1 W / cm ² or more and 500 W / cm ² or less. 6. The decomposition of a thermosetting resin according to claim 1, wherein the thermosetting resin contains at least one kind of bond among an ester bond, a urethane bond and a urea bond. Method. 7. The method for decomposing a thermosetting resin according to claim 1, wherein the thermosetting resin is a polyurethane resin. 8. A means for immersing a thermosetting resin in a solvent,
Means for irradiating ultrasonic waves to the thermosetting resin immersed in the solvent. 9. The thermosetting resin decomposing apparatus according to claim 8, further comprising means for dissolving a gas in the solvent.