JPH07126430A - Method for liquefying waste plastics - Google Patents

Abstract

PURPOSE:To recover a curable resin part, etc., and reutilize the recovered part, etc., as a fuel, etc., by blending a waste plastic with a specific mixture in a specified proportion, heating the resultant blend at a specific temperature or above and efficiently liquefying a matrix constituting the waste plastics. CONSTITUTION:This method for liquefying waste plastics is to blend (A) 100 pts.wt. waste plastic such as an FRP molding with (B) 30-500 pts.wt. mixture of (i) a hydrocarbon, having >=180 deg.C/760mmHg boiling point and containing >=1 benzene nuclei such as diethylbenzene with (ii) a polyhydric alcohol having >=180 deg.C/760mmHg boiling point and >=2 hydroxyl groups in one molecule such as diethylene glycol [at preferably (30-99)/(1-30) blending ratio of the components (i)/(ii) expressed in terms of weight ratio] and then heat the resultant blend at >=180 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention mainly relates to fiber-reinforced reinforced plastics as waste plastics (hereinafter referred to as waste plastics) for which effective recycling (hereinafter also referred to as reuse) and recovery means have not been found. The present invention relates to a method of treating FRP (abbreviated as FRP), and particularly to a method of liquefying a matrix (resin) constituting FRP.

[0002]

2. Description of the Related Art Conventionally, FRP as waste plastic
Since it is a fiber-reinforced thermosetting resin, no recycling method has been found. For example, it has been proposed that crushed molded articles such as SMC and BMC that use a large amount of filler be reused as a filler. However, in this case, in order to pulverize the molded product to obtain a particle size as a practical filler, it is inevitable that the cost will be extremely high, and it has not been generally used. Furthermore, there is no filler or a small amount (resin 1
A general FRP molded article containing only 50 parts or less of filler per 00 parts, such as fishing boats, yachts,
It can be said that crushing is impossible in a bathtub, etc., and even if it is attempted to decompose it by heating, the glass fiber is sublimated, and the residue is like a fiber reinforced carbon molded product and it can not be cleaned up. there were. Therefore, at present, FRP
The moldings are left as they are, discarded or only partially burned.

[0003]

The object of the present invention is to overcome the drawbacks of the conventional methods for treating FRP molded articles as waste plastics and to liquefy and recover the cured resin component in the FRP molded articles. Another object of the present invention is to provide a method for treating waste plastic, in which the filler or reinforcing material component in the FRP molded product can be separated and both components can be reused.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted a study to find a recycling method in which an FRP molded product as waste plastic is treated by some method and the original shape of the FRP molded product is not stopped. By heating the molded article with a suitable low-cost decomposer, it is possible to liquefy the cured resin component, to separate the filler or reinforcing material, and to reuse each component, The above objective was achieved.

That is, in the present invention, [I] (1) the boiling point is 180 ° C. with respect to 100 parts by weight of the waste plastic.
Hydrocarbon containing at least one benzene nucleus of / 760 mmHg or more, and (2) boiling point of 180 ° C / 760 mmHg or more,
It relates to a method for liquefying waste plastics, which comprises blending 30 to 500 parts by weight of a mixture with a polyhydric alcohol having at least two hydroxyl groups in one molecule and then heating the mixture to 180 ° C. or higher.

In the present invention, the liquefied hardened resin portion may be recycled as a recoverable component, or may be used as it is as a fuel. Further, the separated reinforcing material and filler can be dried and pulverized for reuse.

The decomposing agent used for treating the FRP molded article as a waste plastic, which is the point of the present invention, consists of the following types. That is, (1)
A hydrocarbon containing at least one benzene nucleus having a boiling point of 180 ° C / 760 mmHg or more, and (2) a boiling point of 180 ° C / 760
It is a mixture of both components of a polyhydric alcohol having mmHg or more and having at least two hydroxyl groups in one molecule.

(1) The boiling point of the component is 180 ° C./760 mmHg
A hydrocarbon containing at least one of the above benzene nuclei,
The mixing ratio of the polyhydric alcohol having the boiling point of the component (2) of 180 ° C./760 mmHg or more and having at least two hydroxyl groups in one molecule is 30 to 99% by weight of the component (1), preferably 50 to 90%. It is desirable that the content of the component (2) is 1 to 70% by weight, preferably 10 to 50% by weight.

Since the polyester resin is a polymer composed of styrene and an ester bond, it is necessary to have a component acting as both as a decomposing agent, and a hydrocarbon as the component (1) and a polyvalent as the component (2). It is difficult to achieve the object of the present invention with only one of the alcohols.

Among the decomposing agents used in the present invention, hydrocarbons containing at least one benzene nucleus having a boiling point of 180 ° C./760 mmHg or more as the component (1) include the following examples. Diethylbenzene (boiling point: 181-184 ° C), dodecylbenzene (boiling point: 331 ° C), naphthalene (boiling point: 2)
18 ° C.), methylnaphthalene (boiling point: α244.8 ° C.,
β241.0 ° C.), tetralin (boiling point: 207 ° C.), cyclohexylbenzene (boiling point: 240 ° C.), biphenyl (boiling point: 225 ° C.), a heat-resistant solvent containing diphenyl ether. Further, although it is also useful that it has three or more benzene nuclei, for example, anthracene, it is difficult to be advantageous in terms of availability and cost. The most desirable and effective types in terms of cost and action are naphthalene, as well as methylnaphthalene mixtures.

Further, the polyhydric alcohol as the component (2), which is considered to be mainly used in combination with the hydrocarbon as the component (1) to mainly cleave the ester bond in the polyester, is
There is no particular limitation, and examples include the following types. Ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 2-methylpropanediol-1,
3, neopentyl glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 3-methylpentanediol-1,5,1,6-hexanediol, 2,2,4- Trimethylpentanediol-1,3, hydrogenated bisphenol A, bisphenol A alkylene monoepoxide adduct, glycerin, trimethylolpropane, pentaerythritol. Of these, the use of diethylene glycol is most desirable in view of cost and boiling point.

The boiling point of the decomposer used is 180 ° C./76
Even if it is less than 0 mmHg, it can be used, but it requires a considerably high pressure in order to reach the temperature required for decomposition, resulting in high equipment and operation costs.

There is no particular limitation on the polyester resin and vinyl ester resin which constitute the FRP as the waste plastic to be treated, and the types which are generally used at present are applied as they are.

The use ratio of the decomposition agent composed of the mixture of the hydrocarbon as the component (1) and the polyhydric alcohol as the component (2) is
Decomposing agent 30 to 5 per 100 parts by weight of waste plastic
00 parts by weight, preferably 50 to 200 parts by weight. When the use ratio of the decomposing agent is less than 30 parts by weight, the cured resin is not sufficiently decomposed and it is difficult to liquefy. On the other hand, when the amount is more than 500 parts by weight, the treatment can be completed completely, but the amount of the decomposing agent is too large, and the cost is inevitable even if it is recovered or used as a fuel.

In order to decompose the waste plastic with a decomposing agent, it is appropriate to heat it to 180 ° C. or higher, preferably 200 ° C. or higher, more preferably 250 ° C. or higher and 300 ° C. or lower. When the heating temperature is lower than 180 ° C., it takes a long time to process, which is not suitable.

As described above, the optimum temperature for treating the waste plastic (cured resin) with the treatment liquid is 180 ° C. or higher, preferably 200 ° C. or higher, 250 ° C. or higher and 300 ° C. or lower,
At that time, the pressure becomes about 5 to ²⁰ kg / cm ^2, and it is convenient to work by releasing the pressure and removing the volatile matter.

[0017]

EXAMPLES The present invention will be described in more detail with reference to examples.

Example 1 Sample Polyester Resin Synthesis A 2-liter separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas introduction tube was charged with propylene glycol (365 g), phthalic anhydride (296 g), and maleic anhydride (196 g). , 180 to 195 in nitrogen gas stream
After esterification to ℃ to acid value 36.1,
The temperature was changed to 0 ° C under an air stream, and 0.14 g of hydroquinone was added. Then 525 g of styrene was added. A polyester resin (A) was obtained with a Hazen color number of 150 and a viscosity of 4.1 poise.

Preparation of test piece 100 parts by weight of polyester resin (A), 1 part by weight of methyl ethyl ketone peroxide, 0.3 parts of cobalt naphthenate
By weight, 0.1 part by weight of pyrrolidine acetylacetonate (Nippon emulsifier, Naxlace-P) was added, and after gelling at room temperature, the resin cured after 80 ° C. for 2 hours and 120 ° C. for 2 hours was approximately 1 cm square. It was cut into a test piece.
The physical properties of the cured polyester resin (A) were as follows. Flexural strength 10.7 kg / mm ² , flexural modulus 360
kg / mm ² , heat distortion temperature 89 ℃, Rockwell hardness (M)
110.

The above-mentioned test piece 20 is placed in an autoclave.
0 g was added, and further 140 g of naphthalene and 60 g of diethylene glycol were added. After nitrogen substitution, the temperature was gradually raised to 250 ° C. in about 3 hours, and further changed to 280 ° C. in 1 hour. The pressure was 8.1 kg / cm ² , so a small amount of gas was removed and 5 kg /
It was lowered to cm ² . The temperature was maintained at 270 to 280 ° C. for 5 hours and then cooled to room temperature. The contents were completely dissolved and no solid matter remained. A decomposed liquid having a blackish brown viscosity of about 2 poise was obtained. The yield was quantitative, 396 g.

Example 2 As a polyester resin using isophthalic acid as a raw material, 100 parts by weight of Rigolac 2141 manufactured by Showa Highpolymer Co., Ltd., 1.5 parts by weight of methyl ethyl ketone peroxide, and 0.5 parts by weight of cobalt naphthenate were used. The mixture was mixed, cast in a width of 1 cm, and gelled at room temperature. After that, at 80 ℃ for 2 hours,
After post-curing at 120 ° C. for 2 hours, it was cut into a test piece of approximately 1 cm square. In the autoclave, place the cured test piece of Rigolac 2141 in 200 times.
g, methylnaphthalene mixture (α, β) 140 g, and diethylene glycol 60 g were added and the temperature was raised. When the treatment was completed in the same manner as in Example 1, no residual cured product (test piece) was observed, and 398 g of a blackish brown liquid having a viscosity of about 3 poise was obtained.

Example 3 Synthesis of bisphenol type polyester In a 1 liter separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas introduction tube, 350 g of bisphenol A propylene oxide adduct, 11 fumaric acid were added.
After 6 g was charged and esterified in a nitrogen stream at 210 to 215 ° C. to give an acid value of 32.7, 0.08 g of hydroquinone was added at a temperature of 120 ° C. and dissolved in 430 g of styrene. A bisphenol type polyester (B) was obtained with a yellowish brown color and a viscosity of 4.7 poise. Preparation of test piece 100 parts by weight of bisphenol type polyester (B),
2 parts by weight of methyl ethyl ketone peroxide, 1 part by weight of cobalt naphthenate, and 0.2 parts by weight of dimethylaniline were added, and the mixture was cast into a 1 cm width for gelation. After that, 80 ℃
After curing for 2 hours at 120 ° C. for 2 hours, the test piece was cut into about 1 cm square. 200 parts by weight of the above test piece, 200 parts by weight of biphenyl and 40 parts by weight of glycerin were added to the autoclave, and when the pressure reached 5 kg / mm ² or more, the pressure was reduced to 270 to 280 ° C.
Hold for 8 hours. The cured resin was completely dissolved and no residue was observed. Liquid residue weight is 431
It was g.

[0023]

According to the method of the present invention, the matrix (cured resin) constituting the waste plastic can be completely liquefied and recovered, and the filler or reinforcing material in the waste plastic can be separated. . Therefore, the liquefied cured resin portion may be recycled as a recoverable component, or can be used as it is as a fuel. Further, the separated filler or reinforcing material can be dried, crushed and reused.

Claims (2)

[Claims] 1. [I] With respect to 100 parts by weight of waste plastic, [II] (1) a hydrocarbon having a boiling point of 180 ° C./760 mmHg or more and containing at least one benzene nucleus, and (2) a boiling point of 180. 30/500 parts by weight of a mixture with a polyhydric alcohol having at least two hydroxyl groups in one molecule of ℃ / 760 mmHg or higher, and then heating to 180 ° C. or higher. Liquefaction method. 2. The mixing ratio of the hydrocarbon as the component (1) and the polyhydric alcohol as the component (2) is 3 as the hydrocarbon as the component (1).
0 to 99% by weight and polyhydric alcohol of component (2) 1 to
The method for liquefying waste plastic according to claim 1, wherein the method comprises 70% by weight.