JP2002363338A - Solution for treating cured unsaturated polyester resin, method of treatment by using it, and treated product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treating solution which can efficiently treat a cured unsaturated polyester resin at a temperature lower than that usually required for the thermal decomposition thereof and which is reduced in corrosiveness, and a method of treatment by using it, to thereby facilitate the reuse of a cured unsaturated polyester resin. SOLUTION: A cured unsaturated polyester is treated with a treating solution containing a solvent and at least one metal salt or metal hydroxide, obtained by blending them in such a manner that all of the metal salts or metal hydroxides are not completely dissolved at the treating temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a treatment solution for a cured unsaturated polyester resin, a treatment method using the treatment solution, and a treatment product containing a reusable compound.

[0002]

2. Description of the Related Art A cured unsaturated polyester resin is excellent in heat resistance, mechanical properties, weather resistance, chemical resistance, water resistance and the like, and its physical properties can be changed over a wide range. In addition, molding method,
It is widely used as an FRP application because of its characteristics that it can be mass-produced because there is no restriction on its size and shape. For example, house equipment such as bathtubs and septic tanks, wall panels, building materials such as pools, boats, yachts Ship, car, railway and other vehicle parts, electrical equipment, pipes and other industrial equipment, water storage tanks,
It is used in various fields such as containers for corrosion-resistant equipment, other helmets, and various sporting goods.

[0003] As described above, the unsaturated polyester resin cured product has excellent versatility, but on the other hand, there is a problem of pollution of the global environment due to the waste, and it is required to establish a technology for treatment and recycling. Have been. Since the unsaturated polyester resin produced as described above is a thermosetting resin, it does not melt after molding and is insoluble in general-purpose solvents,
Its processing and reuse were difficult. Further, it is difficult to dissolve various fillers to be added for improving mechanical properties and the like, and these materials cannot be reused.

[0004] As a treatment method for this, there is a thermal decomposition method of unsaturated polyester resin. JP-A-8-85736
In this publication, a method for thermal decomposition together with a supply source of a hydroxyl group is specified. There is also a method of chemically decomposing an unsaturated polyester resin. This includes Japanese Unexamined Patent Publication No.
19, a method using a base and a hydrophilic solvent, a method using a base and a monohydric alcohol described in JP-A-8-134340, a method using a glycol described in JP-A-8-225635, -22156
5 methods using dicarboxylic acids or diamines, and a method using diethanolamine described in Japanese Patent Application Laid-Open No. 9-316311.

[0005]

However, none of these is a preferred method of treating a cured unsaturated polyester resin. In the method using thermal decomposition, the required temperature is described in the publication as “The thermal decomposition of resin is carried out at a temperature of about 340 ° C. to 900 ° C.
It is preferable to heat so that the temperature is within the temperature range of ° C, especially around 350 ° C to 450 ° C. 370 ° C. to 390 ° C. in general. Therefore, in the thermal decomposition under an atmosphere containing oxygen, carbon atoms and hydrogen atoms are oxidized and almost all of them are converted into carbon dioxide and water, and it is difficult to reuse the carbon and hydrogen atoms as a raw material for resin synthesis. In thermal decomposition in an atmosphere containing no oxygen, a hydrogen atom bonded to a carbon atom is easily desorbed, and mainly carbon is generated, which is difficult to reuse as a resin raw material. Further, the method of chemically treating is not preferable in consideration of harm to human bodies and safety of the apparatus because corrosive chemical substances are used. However, when a corrosive chemical substance is not used, the processing speed is extremely low, so that it is not practical in terms of efficiency.

[0006] In view of the above, the present invention provides a processing solution and a processing method capable of efficiently processing a cured unsaturated polyester resin at a temperature below the temperature normally required for thermal decomposition with reduced corrosiveness. Thus, it is intended to facilitate the reuse of a cured unsaturated polyester resin.

[0007]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention comprises a solvent and at least one metal salt or metal hydroxide, at least one of which is treated at a processing temperature.
This has been made possible by treating a cured unsaturated polyester resin with a treatment solution formulated so that all of the two metal salts or metal hydroxides are not completely dissolved.

[0008] In the present invention, the term "treatment" means to cut or decompose the bond of the unsaturated polyester resin or to dissolve the unsaturated polyester resin, and furthermore, the monomer which can be recycled from the cured unsaturated polyester resin. Alternatively, it means obtaining a low-molecular compound such as an oligomer. In particular, in the present invention, it means that the cured product of the unsaturated polyester resin reduces its mass.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The treating solution for treating the unsaturated polyester resin cured product of the present invention comprises a solvent and at least one metal salt or metal hydroxide and a solvent as main components, and is a widely used unsaturated solution. A cured product of an unsaturated polyester resin whose main raw material is a saturated polyester resin is to be treated.

[0011] The cured unsaturated polyester resin to be treated is generally made of raw materials such as unsaturated dibasic acids, saturated dibasic acids, glycols, unsaturated vinyl monomers, polymerization inhibitors, accelerators and fillers. It is composed of Unsaturated dibasic acids include maleic anhydride, fumaric acid, itaconic acid, etc.
Saturated dibasic acids include phthalic anhydride, isophthalic acid, adipic acid, tetrabromophthalic anhydride, terephthalic acid, succinic acid, etc.
Ethylene glycol, diethylene glycol and the like are used. Styrene is generally used as the unsaturated monomer from the viewpoint of copolymerizability. Further, quinones and hydroquinones are often used as polymerization inhibitors.

A general method for producing a cured unsaturated polyester resin from the above raw materials is a polycondensation reaction step of an unsaturated polyester accompanied by dehydration, and after dissolving this in an unsaturated vinyl monomer, various additives are added. And adjusting the characteristics thereof. During the whole synthesis, curing is often performed at a temperature ranging from room temperature to 250 ° C., and an inert gas such as nitrogen gas is introduced into the reaction system under an arbitrary pressure.

Examples of metal salts or metal hydroxides used in the treatment solution of the present invention include, but are not limited to,
Lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, titanium, zirconium, vanadium, chromium, manganese, iron, cobalt, nickel, copper,
Silver, palladium, zinc, aluminum, gallium, tin,
Ammonium hydrides, hydroxides, borohydrides, amide compounds, fluorides, chlorides, bromides, iodides, borates, phosphates, carbonates, sulfates, nitrates, organic acid salts, alcoholates, Phenolates and hydrates thereof. These compounds may be used alone or as a mixture of several types. Further, impurities may be contained. Of these, alkali metal salts,
Phosphates, alkali metal phosphates, alkali metal hydroxides or hydrates thereof are preferred.

The solvent used in the treatment solution of the present invention is not limited to the following, but includes formamide, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, , N-dimethylacetamide, N, N, N ',
N'-tetramethylurea, 2-pyrrolidone, N-methyl-2
Amides such as -pyrrolidone, caprolactam, carbamic acid ester, etc., methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, iso-butanol, tert-butanol, 1-pentanol, 2-pentanol , 3-pentanol, 2-methyl-1-butanol, iso-pentyl alcohol, tert-
Pentyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-
Pentanol, 4-methyl-2-pentanol, 2-ethyl
-1-butanol, 1-heptanol, 2-heptanol,
3-heptanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 4-methylcyclohexanol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether,
Ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol,
Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol, polyethylene glycol (molecular weight 200 to 400), 2-
Propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, benzyl alcohol, glycerin, Alcohols such as dipropylene glycol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, 2-hexanone, methyl isobutyl ketone, 2-heptanone, 4-heptanone, diisobutyl ketone, cyclohexanone, methyl cyclohexanone, holon and isophorone System, dipropyl ether, diisopropyl ether, dibutyl ether, dihexyl ether, anisole, phenetole, dioxane, tetrahydrofuran, acetal, ethylene glycol dimethyl ether, ethylene glycol diethyl ether Diethylene glycol dimethyl ether, ether and diethylene glycol diethyl ether, ethyl acetate, esters such as butyl acetate, can be used water, liquid ammonia, a solvent such as inorganic liquid carbon dioxide and the like. These may be used alone or as a mixture of several types. Further, impurities may be contained. Among these solvents, alcohol solvents in which phosphoric acids or salts of phosphoric acids are easily dissolved are preferable. Further, when the treatment is performed under normal pressure or reduced pressure, an alcohol solvent having a boiling point of 170 ° C. or higher is preferable.

The processing solution of the present invention is prepared by mixing an amount of at least one metal salt or metal hydroxide that does not dissolve at the processing temperature with the solvent, and preferably at a concentration of 1 to 80 wt%. And particularly preferably 2
~ 20 wt%. When the content is 1 wt% or less, the processing speed of the cured resin is slow, and many metal salts or metal hydroxides are often dissolved. If the content is 80% by weight or more, the amount of the insoluble metal salt or metal hydroxide is too large, so that it is difficult to adjust the treatment solution and to treat the unsaturated polyester resin cured product.

Further, in the processing solution of the present invention, the solute is in an equilibrium state, and when at least one metal salt or metal hydroxide is inactivated, it immediately compensates for it and is effective.

Further, at least one metal salt or metal hydroxide which is not dissolved in the treatment solution may be present in the treatment solution during storage and treatment, and may be precipitated or dispersed. The method of dispersing is not limited as long as it is a method usually used for dispersing, such as mechanical stirring, bubbling of gas, vibration, ultrasonic vibration and the like.

In addition, the temperature for adjusting the processing solution of the present invention may be any temperature, and the atmosphere for adjusting the processing solution may be nitrogen, argon, carbon dioxide or the like even in the air. It may be in an inert gas, and may be any of normal pressure, reduced pressure, and increased pressure.

Further, an additive such as a surfactant may be optionally added to the thus obtained treatment solution.

As a method for treating a cured unsaturated polyester resin using the treatment solution of the present invention, first, a cured unsaturated polyester resin to be treated is crushed to a size that can be treated. The size of the crushed pieces may be any size,
It is preferably in the range of not more than cubic meters. 0.5
If it is smaller than cubic centimeter, the crushing process will be longer, if it is larger than 1.0 cubic meter, the processing time will be longer, and in any case, the scale of the apparatus will be limited,
The processing efficiency, processing cost, and the like are significantly reduced and are not practical.

The crushing of the cured unsaturated polyester resin can be carried out by, for example, an impact crusher, a shear crusher, a compression crusher, a stamp mill, a ball mill, a rod mill, or the like.

The crushed unsaturated polyester resin cured product is preferably immersed in the treatment solution of the present invention. Of course, the processing solution is not limited to immersion, and for example, the treatment solution can be sprayed and applied by spraying or the like.

The temperature of the processing solution at the time of processing is determined by the solvent or processing solution used at that time.
It is sufficient that the state of the processing solution is liquid. Further, it is arbitrarily determined within a range from the freezing point to the boiling point in order to adjust a desired processing speed, facilitate processing, and the like. In order to prevent deterioration in the quality of the recovered material after the treatment, the treatment is preferably performed at a temperature of 250 ° C. or lower, more preferably at a temperature of 220 ° C. or lower.

The atmosphere during the treatment may be air or an inert gas such as nitrogen, argon or carbon dioxide, and may be any of normal pressure, reduced pressure, and increased pressure. When importance is attached, it is preferable to be under normal pressure.

In order to increase the processing speed, it is effective to apply vibration by ultrasonic waves in addition to heating and pressurizing.

The treated product of the cured unsaturated polyester resin produced as a result of treatment by the treatment solution and the treatment method of the present invention can be effectively reused as a raw material for obtaining an industrially useful resin.

This treatment product is obtained by removing the solvent and the undissolved metal salt or metal hydroxide of the treatment solution of the present invention. The purified treatment product is not particularly limited as long as it is an organic compound, but is more preferably a compound that can be reused as a raw material for resin synthesis. Compounds that can be reused as synthetic raw materials for resins include phenols, glycidyl etherified phenols, metal salts of phenols, amines, carboxylic acids, and their halides and hydrogenated products. In addition, raw materials for industrially producing these compounds are also included. For example, phenol, cresol, dimethylphenol, propylphenol, ethylphenol, hydroquinone, resorcinol, catechol, bisphenol A, bisphenol F, biphenol, dihydroxydiphenyl ether, dihydroxydiphenylsulfone, phenol novolak, cresol novolak, bisphenol A novolak, and glycidyl thereof Examples include ethers, halides, alkali metal salts, and ammonium salts.

Further, the treatment solution of the present invention used once or more can be reused for treating a new cured unsaturated polyester resin.

Hereinafter, the present invention will be described in more detail with reference to examples.

[0030]

EXAMPLE As a cured unsaturated polyester resin, a sample obtained by heating and curing at 170 ° C. for 1 hour using phthalic anhydride, isophthalic acid, maleic anhydride, propylene glycol, ethylene glycol and styrene as raw materials was used. This sample was cut into a size of 10 mm × 30 mm × 3 mm to obtain a test piece. The treatment solution was obtained by weighing a predetermined amount of each of various at least one metal salt or metal hydroxide and a solvent in a test tube and gently stirring at a constant temperature. that time,
At least one metal salt or metal hydroxide in the treatment solution did not completely dissolve, but was settled at the bottom of the tank.

At the time of treatment, the test tube containing the treatment solution was heated in the range of 180 ° C. to 220 ° C. using an oil bath. After measuring the mass of the test piece,
The test piece was immersed in a treatment solution maintained at a temperature in the range from to 220 ° C., taken out after 4 hours, and weighed again. The amount of change in mass before and after the treatment was divided by the total mass of the test piece to calculate the solubility of the cured resin. In the comparative example, the treatment was performed in the same manner with the treatment solution being filtered to remove the insoluble metal salt or metal hydroxide.

The results of the processing rates of Examples 1 to 10 and Comparative Examples 1 to 6 are shown in the table.

[0033]

[Table 1]

Examples 1 to 10 and Comparative Examples 1 to 6 are compared.

As shown in Comparative Examples 1 to 6, when at least one metal salt or metal hydroxide that was not completely dissolved in the solvent was removed, and the treatment was performed without any precipitate in the treatment solution. In each case, the dissolution rate was 2% or less.

On the other hand, as shown in Examples 1 to 10, when the treatment was carried out in a state where at least one metal salt or metal hydroxide was settled at the bottom of the tank, the unsaturated polyester was entirely formed. 10% or more of the cured resin product could be treated. In particular, the dissolution rates of Examples 2 to 4, 9, and 10 are high. Tripotassium phosphate used in Examples 1 to 6 is a food additive and is harmless to the human body.

Although the present invention has been described in a plurality of embodiments, it should not be understood that the description is intended to limit the present invention. From this disclosure, various alternative embodiments, examples, and operation techniques not described herein will be apparent to those skilled in the art. Therefore, the technical scope of the present invention is determined only by the matters specifying the invention according to the claims that are appropriate from the above description.

[0038]

According to the present invention, there is provided a processing solution and a processing method capable of efficiently processing a cured unsaturated polyester resin at a temperature lower than a temperature required for thermal decomposition and having reduced corrosiveness. This makes it easy to reuse the cured unsaturated polyester resin.

Continuation of the front page (72) Inventor Ayako Matsuo 1500 Oji Ogawa, Shimodate-shi, Ibaraki F-term in Hitachi Chemical Industry Research Laboratory (reference) 4F301 AA25 AB02 AB03 CA09 CA23 CA24 CA33 CA43 CA72 4H006 AA05 AC26 BB14 BB15 BC10 BE10 BE90

Claims (13)

[Claims] Claims: 1. A treatment solution for treating a cured unsaturated polyester resin, comprising a solvent and at least one metal salt or metal hydroxide, wherein at a treatment temperature the metal salt or A treatment solution for a cured unsaturated polyester resin, wherein the solution is formulated so that all of the metal hydroxide is not completely dissolved. 2. The treatment solution for a cured unsaturated polyester resin according to claim 1, wherein at least one of the metal salts is an alkali metal salt. 3. The solution for treating a cured unsaturated polyester resin according to claim 1, wherein at least one of the metal salts is a phosphate. 4. The treatment solution for a cured unsaturated polyester resin according to claim 1, wherein at least one of the metal salts is an alkali metal phosphate or a hydrate thereof. 5. The solution for treating a cured unsaturated polyester resin according to claim 1, wherein at least one of the metal hydroxides is an alkali metal hydroxide. 6. The treatment solution for a cured unsaturated polyester resin according to claim 1, wherein the solvent comprises an organic solvent. 7. The treatment solution for a cured unsaturated polyester resin according to claim 1, wherein the solvent comprises an alcohol-based solvent. 8. The solution for treating a cured unsaturated polyester resin according to claim 1, wherein the solvent comprises an alcoholic solvent having a boiling point of 170 ° C. or higher. 9. A method for treating a cured unsaturated polyester resin, comprising the step of treating a cured unsaturated polyester resin with the treatment solution according to claim 1. Description: 10. The temperature of the processing solution at the time of processing is 2
The method for treating a cured unsaturated polyester resin according to claim 9, wherein the temperature is 50C or lower. 11. The method for treating a cured unsaturated polyester resin according to claim 9, wherein the treatment is performed under normal pressure. 12. The method according to claim 9, further comprising the step of crushing the cured unsaturated polyester resin to a size of not less than 0.5 cubic centimeters and not more than 1.0 cubic meters. For treating a cured unsaturated polyester resin. 13. A treatment product of a cured unsaturated polyester resin treated by the treatment method according to any one of claims 9 to 12, comprising a compound that can be reused as a raw material for resin synthesis. Processed product of cured unsaturated polyester resin.