JP4744903B2 - Disassembly method of urethane resin - Google Patents

Description

  The present invention relates to a method for decomposing a urethane resin.

  Urethane resins are generally used widely as cushioning materials for automobile seats, furniture, mattresses, etc., heat insulating materials, structural materials, and paving materials, but are difficult to recycle because they are thermosetting resins with a three-dimensional network structure. At present, disposal such as landfill and incineration is being carried out.

  On the other hand, methods for liquefying urethane resins by chemical methods have been studied for a long time. For example, the polyurethane foam is decomposed with an amine compound such as alkanolamine, and then the decomposition products are separated and recovered, and regenerated as urethane foam, or the polyurethane foam is decomposed using polyol and aminoethanol as the decomposing agent, and the adhesive. In addition, a ketone / aldehyde decomposition method, an isocyanate decomposition method, a thermal decomposition method, a hydrolysis method, a post-stage heating method, and the like are known.

In addition, there is a method of regenerating a urethane resin by reacting a polyol in the decomposition product obtained by decomposition in this way with an isocyanate (see Patent Document 1).
JP-A-7-126344 (page 3)

  However, when the soft urethane resin is decomposed by the conventional decomposition method as described above, the decomposition product is separated into two layers (a polyol component and an amine component). For this reason, in the case of reproduction | regeneration, the effort which isolate | separates a polyol component and an amine component was required. In addition, since the polyol component and the amine component are not completely separated, this separation requires a great deal of labor. Further, when the foamed urethane resin is decomposed by the conventional decomposition method as described above, heat is difficult to be transmitted to the foamed urethane resin, so that it takes a long time for the decomposition.

  The present invention has been made to solve the above problems. That is, an object of the present invention is to provide a method for decomposing a urethane resin that can suppress the separation of decomposition products and can decompose the urethane resin in a short time.

The urethane resin decomposing method of the present invention is a urethane resin decomposing method characterized by chemically decomposing a soft urethane resin in the presence of a filler , wherein the filler is a carbonate carbonate.
Any one or more of Cium and Fe ₂ O ₃ and an average particle size of 0.01 μm or more and 50 μm or less
The lower granular filler or fibrous filler having a fiber diameter of 5 μm or less and a fiber length of 10 μm or less
It is characterized by.

  According to the present invention, separation of decomposition products can be suppressed, and a urethane resin can be decomposed in a short time.

  Hereinafter, embodiments will be described. In the present embodiment, the urethane resin is chemically decomposed using, for example, a decomposing agent in the presence of the filler.

(Urethane resin)
The urethane resin to be decomposed is various urethane resins such as soft, semi-rigid, rubber, elastomer, RIM, paint, and adhesive, and the molecular weight of the raw material polyol is 500 or more, preferably 2000 or more. Examples of products include urethane for car seats, cushion materials for chairs, bed mats, industrial iron rolls, solid tires, flooring materials, automobile bumpers, sealing agents, adhesives, and the like.

(Decomposing agent)
The chemical decomposition of the urethane agent may be any generally known chemical decomposition of the urethane resin, and examples thereof include polyol decomposition, amine decomposition, hydrolysis, and acid decomposition. By the above-described decomposition method employed, the urethane resin is chemically decomposed using a decomposition agent such as an alcohol group, amino group, water, carboxyl group and derivatives thereof, an epoxy group, or an isocyanate group-containing compound.

  Specific examples of the decomposition agent are given below.

1. Alcohol group-containing decomposing agent Examples of the decomposing agent containing an alcohol group include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, 1,2,6-hexanetriol, triethanolamine, pentaerythritol, Examples include ethylenediamine, tolylenediamine, diphenylmethanediamine tetramethylolcyclohexane, and methylglucoside.

2. Amino group-containing decomposition agent Examples of the decomposition agent having an amino group include monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, propanediamine, 2-ethylhexylamine, isopropanolamine, 2- (2- Aminoethylamino) ethanol, 2-amino-2-hydroxymethyl-1,3-propanediol, ethylaminoethanol, aminobutanol, n-propylamine, di-n-propylamine, n-amylamine, isobutylamine, methyldiethylamine , Cyclohexylamine, piperazine, piperidine, aniline, toluidine, benzylamine, phenylenediamine, xylylenediamine, chloroaniline, pyridine, picoline, N-methylmolybdenum Ruphorin, ethylmorpholine, and pyrazole are mentioned. There is no problem even if these compounds are mixed and used.

3. Carboxyl Group and Derivative-Containing Decomposition Agent Examples of carboxyl group derivatives include carboxyl group salts and esters, or acid anhydrides.

  Specific examples of the decomposing agent containing a carboxyl group and its derivatives include formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, itaconic acid, propiolic acid, oleic acid, acrylic acid, methacrylic acid, oxalic acid and maleic acid. , Fumaric acid, phthalic acid, itaconic acid, malonic acid, succinic acid, adipic acid, benzoic acid, citraconic acid, crotonic acid, glutaric acid, hexanoic acid, glycolic acid, lactic acid, malic acid, tartaric acid, citric acid, sugar acid, Examples thereof include glyceric acid, gluconic acid, salicylic acid, trimellitic acid, cyclopentanetetracarboxylicmethylhexahydrophthalic acid, hexahydrophthalic acid, and organic acids that have undergone intramolecular dehydration such as acid anhydrides and lactones thereof. Further, it may be a compound having both a carboxyl group and an acid anhydride in the molecule, such as trimellitic anhydride. Further, salts of these organic acids typified by sodium salt, potassium salt, calcium salt and the like, and esters of these organic acids typified by methyl acetate, ethyl acetate, propyl acetate and the like with substances having a hydroxyl group can be mentioned. Furthermore, amino acids such as glycine, alanine, valine, leucine, isoleucine, glutamine, serine, phenylalanine, and glutamic acid can also be used. A plurality of these may be bonded, or an imino acid having an intramolecular bond such as proline may be used. It can use similarly in the optical isomer of these compounds.

4). Epoxy group-containing decomposition agent As the decomposition agent having an epoxy group, ethylene oxide, propylene oxide, butyl glycidyl ether, allyl glycidyl ether, allyl 2,3-epoxypropyl ether, benzyl glycidyl ether, butanediol diglycidyl ether, butyl 2, From epoxy resins such as 3-epoxypropyl ether, ethylene glycol diglycidyl ether, phenyl glycidyl ether, 1,2-epoxyethylbenzene, 2,3-epoxy-1-propanol, 2,3-epoxypropyl methyl ether, etc. Known bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, naphthol type Novolac epoxy resin, bisphenol A novolak epoxy resin, naphthalene diol epoxy resin, alicyclic epoxy resin, epoxy resin derived from tri- or tetra (hydroxyphenyl) alkane, bishydroxybiphenyl epoxy resin, phenol aralkyl Examples include epoxidized resins.

5. Isocyanate group-containing decomposer As isocyanate group-containing decomposer, monoisocyanate compounds such as phenyl isocyanate, diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), xylylene diisocyanate, tetramethylxylylene diisocyanate, 3-isocyanatomethyl −3,5,5-trimethylcyclohexyl isocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), bis (isocyanatomethyl) cyclohexane, hexamethylene diisocyanate and other compounds having multiple isocyanate groups, and polymeric MDI The compound can be used.

  In addition, you may use the various decomposition agent mentioned above individually or in mixture of 2 or more types.

(Decomposition catalyst)
In the decomposition reaction using the above decomposition agent, if necessary, a decomposition catalyst can be added to the urethane resin and the decomposition agent to increase the decomposition rate.

  As the decomposition catalyst to be added, those used at the time of producing the urethane resin are preferable. For example, triethylamine, N, N-dimethylcyclohexylamine, N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′ , N′-tetramethylpropane 1,3-diamine, N, N, N ′, N′-tetramethylhexane 1,6-diamine, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine, N , N, N ′, N ″, N ″ -pentamethyldipropylenetriamine, tetramethylguanidine, triethylenediamine, N, N′-dimethylpiperazine, N, -methyl, N ′-(2-dimethylamino) ethylpiperazine, N-methylmorpholine, N- (N ′, N′-dimethylaminoethyl) -morpholine, 1,2-dimethylimidazole, Xamethylenetetramine, dimethylaminoethanol, dimethylaminoethoxyethanol, N, N, N′-trimethylaminoethylethanolamine, N-methyl-N ′-(2-hydroxyethyl) -piperazine, N- (2-hydroxyethyl) Morpholine, bis (2-dimethylaminoethyl) ether, ethylene glycol bis (3-dimethyl) -aminopropyl ether, stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin marker peptide, dibutyltin thiocarboxylate, dibutyl Examples include indimaleate, dioctyltin marker peptide, dioctyltin thiocarboxylate, lead octenoate, and potassium octenoate.

  The addition amount of the cracking catalyst is preferably from 0.01 to 10 parts by weight, more preferably from 0.1 to 5 parts by weight, based on 100 parts by weight of the cracking agent. If the addition amount of the cracking catalyst exceeds 10 parts by weight, it is not preferable because it is difficult to control the reaction at the time of regeneration, and if the addition amount of the cracking catalyst is less than 0.01 parts by weight, the effect of the catalyst cannot be obtained sufficiently. There is.

(Filler)
The filler is preferably one that is not decomposed by the above-described decomposition agent, and preferably has a higher thermal conductivity (0.5 W / m · K or more) than the urethane resin. Examples of fillers include calcium carbonate ,
Fe ₂ O ₃ is preferred.

  The filler is desirably contained in an amount of 5% by weight or more and 50% by weight or less, and preferably 10% by weight or more and 30% by weight or less, based on a decomposition product obtained by decomposing the urethane resin. When the amount of the filler is less than 5% by weight, the dispersion ratio of the filler to the urethane resin is lowered, so that the effect of preventing separation is reduced, and further, the void ratio of the urethane resin cannot be sufficiently filled, thereby promoting the reaction. Is difficult to appear. On the other hand, if the amount of the filler exceeds 50% by weight, handling becomes difficult, and the regeneration is hindered.

When the filler is granular, the average particle size is preferably 0.01 μm or more and 50 μm or less, and when the filler is fibrous, the fiber diameter is 5 μm or less and the maximum fiber length is 10
It is preferable that it is below μm.

  The filler may be mixed with the urethane resin at the time of decomposition of the urethane resin, or may not be added at the time of decomposition if it is contained in advance in the urethane resin.

(Disassembly method)
The decomposition method is not particularly limited as long as it is a method of heating and stirring a mixture of a urethane resin and a decomposition agent, and can be used regardless of a batch type or a continuous type.

  The continuous method is a method in which urethane resin is caused to flow through a heated channel. For example, a decomposing agent and urethane resin or the like are put into a continuous device such as an extruder provided with a helical stirrer coaxial with a cylinder, the cylinder is heated, and the urethane stirrer is rotated to rotate the urethane resin (and (Or decomposed product) is moved in one direction in the cylinder and continuously decomposed while kneading the urethane resin. Here, when a filler is included in the urethane resin, the filler may or may not be added to the continuous device together with the urethane resin. However, when the urethane resin does not include the filler, the urethane resin The filler is put into the continuous device together with the resin.

  In the continuous decomposition method, although it differs somewhat depending on the type of the urethane resin and the decomposition agent, the outlet resin temperature is usually 80 ° C. or higher and 300 ° C. or lower, and the residence time (time required for passage through the cylinder) is 2. It can be set to be more than minutes. Here, the outlet resin temperature is the temperature of the volume-reduced product at the outlet in the continuous device. In addition, since the resin is kneaded in the decomposition using an extruder, a small amount of a decomposing agent can be uniformly contacted with the urethane resin, and the urethane resin is also heated uniformly. It becomes possible to obtain a uniform decomposition product.

  The batch method is a method in which a decomposition agent, a urethane resin, and the like are heated in a reaction vessel while stirring for a predetermined time. Here, if the urethane resin contains a filler, the filler may or may not be charged into the reaction vessel together with the urethane resin, but if the urethane resin does not contain a filler, the urethane resin Fill the reaction vessel with the resin. The heating temperature is usually set to 80 ° C. or more and 300 ° C. or less, and the heat treatment may be performed for 30 minutes to 3 hours.

  In the present embodiment, since the urethane resin is chemically decomposed in the state where the filler is present, the compatibility of the polyol component and the amine component in the decomposed product is enhanced by the effect of adsorption by the filler, and the polyol component. The amine component is difficult to separate. Thereby, isolation | separation of a decomposition product can be suppressed. Further, since it is not necessary to separate the polyol component and the amine component, it is easy to use the decomposed product. Further, the presence of the filler makes it easy for heat to be transferred to the urethane resin during the decomposition reaction. Thereby, a urethane resin can be decomposed | disassembled in a short time.

  Hereinafter, it demonstrates in detail based on an Example. First, four types of urethane resins A to D were prepared.

(Urethane resin A)
430 parts by weight of polyoxypropylene diol having an average molecular weight of 2000 (manufactured by Mitsui Takeda Chemical Co., product number DIOL-2000), 400 parts by weight of polyoxypropylene triol having an average molecular weight of 5,000 (MN-5000 made by Mitsui Takeda Chemical), toluene diisocyanate (2,4-isomer / 2,6-isomer = 80/20; manufactured by Mitsui Takeda Chemical Co., product number T-80) 123 parts by weight are uniformly mixed and reacted at 80 ° C. for 3 hours to obtain a terminal isocyanate group. A prepolymer (main agent) having a content of 2.9% was obtained.

Further, 7.5 parts by weight of MOCA (3,3′-dichloro-4,4′-diaminodiphenylmethane), 20 parts by weight of polyoxypropylene diol having an average molecular weight of 3000, 20 parts by weight of polyoxypropylene triol having an average molecular weight of 5000, DOP (Dioctyl phthalate) 6 parts by weight, calcium carbonate 39.5 parts by weight, lead octylate (Pb content 25% by weight) 2 parts by weight, Fe ₂ O ₃ (Bengara) 5.0 parts by weight, A curing agent was obtained by uniformly kneading.

  100 parts by weight of the main agent, 100 parts by weight of the curing agent, and 4 parts by weight of L-5420 (Nippon Unicar Co., Ltd. foam stabilizer) were stirred using a stirring foaming device and cured at room temperature to obtain urethane resin A.

(Urethane resin B)
A polyether polyol having an average molecular weight of 3000 and an isocyanate (a mixture of 20% tolylene diisocyanate (TDI) and 80% polymethylene polyphenyl polyisocyanate (polymeric MDI): TM20) are reacted as a main material, molded, and seat cushion. The urethane resin B which is a soft urethane resin used for the material was obtained.

(Urethane resin C)
Moisture curable polyurethane having an NCO group content of 10 wt% and a viscosity of about 4000 cps / 25 ° C. obtained by reacting tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, a polyether polyol having a molecular weight of 1000, and a polyether polyol having a molecular weight of 3000 The urethane resin C which is an elastic binder was obtained.

Example 1
Urethane resin A (urethane elastomer) and diethanolamine were mixed in advance so that the weight ratio was 10/1. Here, the urethane resin A contains 19.8% by weight of calcium carbonate (filler) having an average particle size of 0.1 μm and Fe ₂ O ₃ (filler) having an average particle size of 0.04 μm. ) Was contained by 2.5% by weight. Moreover, the ratio of the filler (total of calcium carbonate and Fe ₂ O ₃ ) to this mixture was 20.3% by weight.

  This mixture was decomposed using an extruder. The cylinder part of the extruder was heated to 200 ° C., and the rotation of the screw was controlled so that the residence time was 3 minutes. From the outlet, a paste-like decomposition product was discharged at 24 kg / h. The decomposition product had an OH value of 230 mgKOH / g.

(Example 2)
Urethane resin B, diethanolamine, and silica (filler) having an average particle diameter of 50 μm were preliminarily mixed so that the weight ratio was 8/1 / 0.5. Here, since the filler is not contained in the urethane resin B, the filler was only silica. Moreover, the ratio of the filler with respect to this mixture was 5.2 weight%.

  This mixture was decomposed using an extruder. The cylinder part of the extruder was heated to 230 ° C., and the rotation of the screw was controlled so that the residence time was 5 minutes. From the outlet, a paste-like decomposition product was discharged at 23 kg / h. The decomposition product had an OH value of 180 mg KOH / g.

(Example 3)
A wood chip, stone and sand were bonded with urethane resin C to implement a water-permeable roadbed material. The roadbed material was pulverized and subjected to wind sorting so that the urethane resin C was 20% by weight or more, and then stones and wood chips were removed. In this roadbed material sorting product, sand (filler) having an average particle diameter of 400 μm is mixed in addition to urethane resin C, and when a decomposition agent is mixed with this, the weight ratio of urethane resin C / decomposition agent / sand is 10 / It was 1/10. Here, since the urethane resin C does not contain a filler, the filler was only sand. Moreover, the ratio of the filler with respect to this mixture was 48 weight%.

  This mixture was placed in a batch-type heated mixing kettle equipped with stirring blades and heated at 200 ° C. After 1 hour, the urethane resin C was decomposed, and the decomposition product was entirely clay-like.

Example 4
Urethane resin A, diethanolamine, and talc (filler) were mixed in advance so that the weight ratio was 10/1/1. Here, as described above, the urethane resin A contains 19.8% by weight of calcium carbonate (filler) and 2.5% by weight of Fe ₂ O ₃ (filler). The filler was composed of calcium carbonate, Fe ₂ O ₃ and talc. The ratio of the filler (total of calcium carbonate, Fe ₂ O ₃ and talc) to this mixture was 27% by weight.

  This mixture was decomposed using an extruder. The cylinder part of the extruder was heated to 200 ° C., and the rotation of the screw was controlled so that the residence time was 3 minutes. From the outlet, a paste-like decomposition product was discharged at 25 kg / h. The decomposition product had an OH value of 200 mg KOH / g.

(Comparative example)
Urethane resin B and diethanolamine were mixed in advance so that the weight ratio was 8/1. Here, since the filler is not contained in the urethane resin B, and no filler is added, the mixture does not contain a filler.

  This mixture was decomposed using an extruder. The cylinder part of the extruder was heated to 230 ° C., and the rotation of the screw was controlled so that the residence time was 5 minutes. From the outlet, the decomposed product was discharged at 19 kg / h in a state of being separated into two layers. The OH value of the upper layer of this decomposition product was 170 mgKOH / g.

A summary of the results of Examples 1 to 4 and the comparative example is shown in Table 1.

  As shown in Table 1, in the comparative example, the decomposed product was separated, whereas in Examples 1 to 4, the decomposed product was not separated but was in the form of paste or clay. From this result, it was confirmed that the decomposition of the decomposed product can be suppressed by decomposing the urethane resin in the presence of the filler. Moreover, the processing amount per unit time was larger in Examples 1-4 than in the comparative example. From this result, it was confirmed that the urethane resin can be decomposed in a short time by decomposing the urethane resin in a state where the filler is present.

Claims (2)

A method for decomposing a urethane resin characterized by chemically decomposing a soft urethane resin in the presence of a filler,
The filler is at least one of calcium carbonate and Fe ₂ O ₃ and has an average particle size of 0
. A method for decomposing a urethane resin, which is a granular filler having a diameter of 01 μm or more and 50 μm or less or a fibrous filler having a fiber diameter of 5 μm or less and a fiber length of 10 μm or less. The filler is 5% by weight or more and 50% by weight with respect to a decomposition product obtained by decomposing the urethane resin.
The method for decomposing a urethane resin according to claim 1 , wherein the urethane resin is contained in an amount of not more than% by weight.