Methods for manufacturing recycled plastics and their products

Abstract

A method for producing recycled plastic includes the following steps: (a) mixing a waste plastic mainly composed of polyterephthalate and polyurethane with a depolymerizing agent, and depolymerizing the waste plastic at a first temperature to obtain a plastic depolymer, the plastic depolymer comprising waste synthetic composite fibers; (b) mixing the plastic depolymer with a first polyether polyol and polymerizing it at a second temperature to obtain a polymeric diol mixture; and (c) mixing the polymeric diol mixture, a second polyether polyol, a polyisocyanate, and a solvent, and reacting them at a third temperature to obtain a recycled plastic having urethane groups. The recycled plastic produced by this method can be used to make films and composite fabrics with waterproof and breathable properties.

Description

Technical Field

[0001] The present invention relates to a recycled plastic, in particular to a recycled plastic obtained by polymerizing a resin raw material comprising a plastic depolymerization product, a polyether polyol and a polyisocyanate, a preparation method thereof and a product thereof. Prior Art

[0002] The current process of recycling discarded clothing or fabric into regenerated fiber requires a single-component (100%) fiber material or a polyester fiber material of at least 97%. This fiber can then be processed through physical recycling (e.g., mechanical cutting or pulverization followed by injection molding) and chemical recycling (e.g., bleaching and alcoholysis followed by polymerization) to produce regenerated fiber.

[0003] In addition, films made from the above-mentioned regenerated fibers generally have difficulty meeting the requirements for waterproof and breathable fabrics. Summary of the Invention

[0004] Therefore, the first object of the present invention is to provide a recycled plastic that can overcome the above-mentioned shortcomings of the prior art.

[0005] The recycled plastic of the present invention is obtained by polymerizing a resin raw material. The resin raw material comprises: a plastic depolymer, a polyether polyol, a polyisocyanate, and a solvent. The plastic depolymer comprises a first monomer and a second monomer. The first monomer has the following structure: [R , x , ]-OOC-Ph-COO- [R' , x , ]-OH, the second monomer has the following structure: HO- [R , x , ]-OOC-HN- [R]-NH-COO- [R' , x , ]-OH. Wherein, Ph represents a benzene ring, [R , x , ]and [R' , x, ] are each independently selected from -CH 2CH 2-, -CH 2CH 2OCH 2CH 2-, -(CH 2CH 2O) n- or -(CH 2CH 2O) nCH 2CH 2-, n is 6 to 23, [R] is selected from diphenylmethane diyl, toluene diyl, 、 Or -CH 2CH 2CH 2CH 2CH 2CH 2-.

[0006] A second object of the present invention is to provide a method for preparing recycled plastics, comprising the following steps:

[0007] (a) mixing a waste plastic mainly composed of polyester terephthalate and polyurethane with a depolymerizing agent, and depolymerizing the waste plastic at a first temperature to obtain a plastic depolymer, wherein the plastic depolymer is as described above;

[0008] (b) mixing the plastic depolymer with a first polyether polyol and polymerizing the mixture at a second temperature to obtain a polymeric diol mixture; and

[0009] (c) mixing the polymeric diol mixture, a second polyether polyol, a polyisocyanate, and a solvent, and reacting them at a third temperature to obtain the recycled plastic having a carbamate group.

[0010] A third object of the present invention is to provide a nonporous film obtained by coating and heating the recycled plastic described above. The nonporous film has a thickness ranging from 10 to 30 μm and a weight ranging from 10 to 30 g / m². The nonporous film exhibits a water pressure resistance greater than 10,000 mmH²O as tested using JIS L1092B, and a moisture permeability greater than 120,000 g / m² / 24 h as tested using JIS L1099B1.

[0011] A fourth object of the present invention is to provide a microporous film obtained by coating, coagulating, washing, and heating the recycled plastic described above. The thickness of the microporous film ranges from 30 to 90 μm, the weight ranges from 10 to 30 g / m², and the water pressure resistance of the microporous film, as tested using JIS L1092B, is greater than 10,000 mmH²O. The moisture permeability, as tested using JIS L1099A1, is greater than 3,000 g / m² / 24 h.

[0012] The fifth object of the present invention is to provide a composite fabric comprising a base fabric and a film attached to the base fabric. The film is selected from the non-porous film or the microporous film as described above.

[0013] The utility model has the following effects: the recycled plastic obtained by polymerizing a resin raw material containing the plastic depolymer can be made into a film and a composite fabric having waterproof and moisture-permeable effects. Implementation Method

[0014] The recycled plastic of the present invention is obtained by polymerizing a resin raw material. The resin raw material comprises: a plastic depolymer, a polyether polyol, a polyisocyanate, and a solvent. The plastic depolymer comprises a first monomer and a second monomer. The first monomer has the following structure: HO- [R , x , ]-OOC-Ph-COO- [R' , x , ]-OH, the second monomer has the following structure: HO- [R , x , ]-OOC-HN- [R]-NH-COO- [R' , x , ]-OH. Wherein, Ph represents a benzene ring, [R , x , ]and [R' , x , ] are each independently selected from -CH 2CH 2-, -CH 2CH 2OCH 2CH 2-, -(CH 2CH 2O) n- or -(CH 2CH 2O) nCH 2CH 2-, n is 6 to 23, [R] is selected from diphenylmethanediyl, toluenediyl, 、 Or -CH 2CH 2CH 2CH 2CH 2CH 2-.

[0015] Preferably, the resin raw material further comprises a small molecule polyol. More preferably, the small molecule polyol is selected from 1,2-ethylene glycol (EG), 1,3-propylene glycol (PDO), 1,2-propylene glycol (PG), 1,4-butanediol (BDO), or 1,6-hexanediol (HDO).

[0016] Preferably, the polyether polyol is selected from polyethylene glycol (PEG), polytetramethylene ether glycol (PTMEG) or polypropylene glycol (PPG).

[0017] Preferably, the polyisocyanate is selected from methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), m-xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI) or hexamethylene diisocyanate (HDI).

[0018] The method for preparing recycled plastics of the present invention comprises the following steps:

[0019] (a) mixing a waste plastic mainly composed of polyethylene terephthalate and polyurethane with a depolymerizing agent, and depolymerizing the waste plastic at a first temperature to obtain the plastic depolymerized product described above;

[0020] (b) mixing the plastic depolymer with a first polyether polyol and polymerizing the mixture at a second temperature to obtain a polymeric diol mixture; and

[0021] (c) mixing the polymeric diol mixture, a second polyether polyol, a polyisocyanate and a solvent, and reacting them at a third temperature to obtain the recycled plastic having the urethane group.

[0022] Preferably, the first temperature is higher than the second temperature, and the second temperature is higher than the third temperature.

[0023] Preferably, in step (c), the polyisocyanate is mixed with the polymeric diol mixture in two stages.

[0024] Preferably, the depolymerizing agent is selected from ethylene glycol, 1,2-propylene glycol, diethylene glycol (DEG), polyethylene glycol, or a combination thereof.

[0025] Preferably, the first polyether polyol and the second polyether polyol are independently selected from polyethylene glycol, polytetramethylene ether glycol or polypropylene glycol.

[0026] Preferably, the step (c) is to mix the polymeric diol mixture, a second polyether polyol, a polyisocyanate, a solvent and a small molecule polyol, and react at a third temperature.

[0027] The non-porous film of the present invention is obtained by coating and heating the recycled plastic described above. The thickness of the non-porous film ranges from 10 to 30 μm, the weight ranges from 10 to 30 g / m², and the water pressure resistance of the non-porous film is greater than 10,000 mmH²O as tested by JIS L1092B. The water vapor permeability of the non-porous film is greater than 120,000 g / m² / 24 h as tested by JIS L1099B1.

[0028] The microporous film of the present invention is obtained by coating, coagulating, washing, and heating the recycled plastic described above. The thickness of the microporous film ranges from 30 to 90 μm, and the weight ranges from 10 to 30 g / m². The water pressure resistance of the microporous film measured using JIS L1092B is greater than 10,000 mmH²O, and the moisture permeability measured using JIS L1099A1 is greater than 3,000 g / m² / 24 h.

[0029] The composite fabric of the present invention comprises a base fabric and a film attached to the base fabric, wherein the film is selected from the non-porous film or the microporous film as described above.

[0030] The present invention will be further described with reference to the following examples. However, it should be understood that these examples are for illustration purposes only and should not be construed as limiting the implementation of the present invention.

[0031] [<Example 1] [〉]

[0032] The recycled plastic of Example 1 is prepared by the following steps:

[0033] (a) 1000 g of waste composite fiber (polyurethane-coated polyethylene terephthalate fiber, with a polyurethane content of 20 wt% and a polyethylene terephthalate content of 80 wt%), 2760 g of diethylene glycol (DEG) as a depolymerizing agent, 0.5 g of zinc acetate (catalyst), and 0.6 g of Irganox® 1010 (antioxidant) were mixed and stirred at 240°C under nitrogen for 2–3 h to depolymerize the waste composite fiber. The mixture was then cooled to 150°C and filtered through a stainless steel filter (pore size 10 μm) coated with diatomaceous earth to obtain a plastic depolymerized product.

[0034] (b) 3762.1 g of the plastic depolymer obtained in step (a), 640 g of PEG2000 (as a polyether polyol), and 0.1 g of tetraisopropyl titanate (as a catalyst) were mixed and heated to 160-200° C. for polymerization. During the polymerization, vacuum was applied (controlling the absolute pressure below 10 torr) to remove excess DEG and byproducts (e.g., ethylene glycol) in the plastic depolymer, to obtain a polymerized diol mixture [hydroxyl value of 20.6 mgKOH / g, number average molecular weight of 5446, and polydispersity index (PDI) of 5.51].

[0035] (c) 171.96 g of the polymeric diol mixture obtained in step (b), 22.73 g of PEG2000 (as a polyether polyol), 23.25 g of 1,4-butanediol (BDO, as a small molecule polyol), 0.1 g of stannous octoate (T9, as a catalyst), 0.1 g of Irganox®1010 (as an antioxidant), and 698.34 g of diethylformamide (DEF, as a solvent) were mixed and stirred at 60°C for 30 min. Then, 48.8 g of 4,4'-diphenylmethane diisocyanate (4,4'-MDI, as a polyisocyanate) was slowly added to react (exothermic). After the system temperature reached a stable state and no longer rose, the system was maintained at 80°C with stirring for 2 h. Then, 32.552 g of 4,4'-MDI was slowly added to react for 3 to 4 minutes. h, to obtain the recycled plastic having urethane groups of Example 1 (solid content of approximately 30% and viscosity of approximately 56270 cP).

[0036] [<Example 2] [〉]

[0037] The method for preparing the recycled plastic of Example 2 is similar to that of Example 1, except that in Example 2, in step (a), waste synthetic fiber (polyurethane content: 45 wt %, polyester content: 55 wt %) is substituted for waste synthetic fiber (polyurethane content: 20 wt %, polyester content: 80 wt %), in step (b), PTMEG1000 is substituted for PEG2000 (as the polyether polyol), and in step (c), PTMEG2000 is substituted for PEG2000 (as the polyether polyol). Finally, the recycled plastic having urethane groups of Example 2 (solid content: approximately 25% and viscosity: approximately 20,000-40,000 cP) is obtained.

[0038] [<Preparation and property testing of non-porous films>]

[0039] The recycled plastic having urethane groups obtained in Example 1 was coated into a film (approximately 62 inches wide) and heated in an oven at a rate of 15 m / min (oven length 28 m, temperature gradient 60°C (0-4 m), 80°C (4-8 m), 110°C (8-12 m), 130°C (12-16 m), 150°C (16-20 m), 150°C (20-24 m), and 150°C (24-28 m)) to produce the non-porous film of Example 1 (approximately 19-20 μm in thickness and 16.7-17.0 g / m2 in weight).

[0040] The water pressure resistance of the non-porous film of Example 1 was tested using JIS L1092B, and the result was greater than 15,000 mmH₂O. The moisture permeability of the non-porous film of Example 1 was tested using JIS L1099B1 (n=3), and the average result was 125,776 g / m₂·24 h.

[0041] [<Microporous Film Preparation and Property Testing>]

[0042] The recycled plastic having urethane groups obtained in Example 2 was coated onto a polyethylene terephthalate (PET) plain woven fabric (40 D × 40 D) coated with a release agent to form a film (approximately 60 inches wide). The film was then passed through a coagulation tank (18 m long) containing a 15% DMF aqueous solution and five water washing tanks (containing 45° C. pure water, each 2 m long) at a rate of 18 m / min. The film was then heated in an oven (15 m long, with a temperature gradient of 120° C. (0-3 m), 130° C. (3-6 m), 140° C. (6-9 m), 150° C. (9-12 m), and 150° C. (12-15 m)). After winding, the film was subjected to a substrate peeling machine. The film was separated from the PET plain fabric using a microporous film machine (purchased from Huaiyu Machinery Co., Ltd., model HYK-1126-4) to obtain the microporous film of Example 2 (film thickness of approximately 56 μm, weight of approximately 22.1 g / m2, pore size of approximately 2 μm or less).

[0043] The water pressure resistance of the microporous film of Example 2 was tested using JIS L1092B, and the result was approximately 10,500 mmH₂O. The moisture permeability of the microporous film of Example 2 was tested using JIS L1099A1, and the result was approximately 3,400 g / m₂·24 h.

[0044] Composite fabric preparation and property testing

[0045] Reactive hot melt polyurethane adhesive (TYFORCE NH-321, purchased from DIC Corporation of Japan) preheated to 100°C was coated on one side of the nonporous film obtained in Example 1 and one side of the microporous film obtained in Example 2. The films were then laminated to a 30D × 30D PET plain woven base fabric using the reactive hot melt polyurethane adhesive to obtain the composite fabrics of Examples 1 and 2, respectively.

[0046] The water pressure resistance of the composite fabrics of Examples 1 and 2 was tested using JIS L1092B, with the results being greater than 20,000 mmH₂O and greater than 10,000 mmH₂O, respectively. The moisture permeability of the composite fabric of Example 1 was tested using JIS L1099B1, with the result being greater than 30,000 g / m₂·24 h; and the moisture permeability of the composite fabric of Example 2 was tested using JIS L1099A1, with the result being greater than 2,000 g / m₂·24 h.

[0047] In summary, the recycled plastic obtained by polymerizing a resin raw material containing the plastic depolymer can be made into a film and composite fabric having waterproof and moisture-permeable effects, thereby effectively achieving the purpose of the present invention.

[0048] However, the above is merely an embodiment of the present invention and should not be used to limit the scope of implementation of the present invention. All simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the patent specification are still within the scope of the patent of the present invention.

Claims

1. A method for producing recycled plastic, comprising the steps of: (a) mixing a waste plastic mainly composed of polyterephthalate and polyurethane with a depolymerizing agent, and depolymerizing the waste plastic at a first temperature to obtain a plastic depolymer, the plastic depolymer comprising waste synthetic composite fibers; (b) mixing the plastic depolymer with a first polyether polyol and polymerizing it at a second temperature to obtain a polymeric diol mixture; and (c) mixing the polymeric diol mixture, a second polyether polyol, a polyisocyanate and a solvent, and reacting it at a third temperature to obtain a recycled plastic having urethane groups.

2. The method for producing recycled plastic as described in claim 1, wherein, The first temperature is higher than the second temperature, and the second temperature is higher than the third temperature.

3. The method for producing recycled plastic as described in claim 1, wherein, In step (c), the polyisocyanate is mixed with the polymeric diol mixture in two stages.

4. The method for producing recycled plastic as described in claim 1, wherein, The depolymerizing agent is selected from ethylene glycol, 1,2-propanediol, diethylene glycol, polyethylene glycol, or combinations thereof.

5. The method for producing recycled plastic as described in claim 1, wherein, The first polyether polyol and the second polyether polyol are each independently selected from polyethylene glycol, polytetramethylene ether glycol or polypropylene glycol.

6. The method for producing recycled plastic as described in claim 1, wherein, Step (c) involves mixing the polymer diol mixture, a second polyether polyol, a polyisocyanate, a solvent, and a small molecule polyol, and reacting them at a third temperature.

7. The method for producing recycled plastic as described in claim 1, wherein, In step (c), the polyisocyanate is selected from diphenylmethane diisocyanate, toluene diisocyanate, isophthalimide diisocyanate, isoflavone diisocyanate or hexamethylene diisocyanate.

8. The method for producing recycled plastic as described in claim 6, wherein, In step (c), the small molecule polyol is selected from 1,2-ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol or 1,6-hexanediol.

9. A method for preparing a non-porous film, comprising the following steps: (a) mixing a waste plastic mainly composed of polyterephthalate and polyurethane with a depolymerizing agent, and depolymerizing the waste plastic at a first temperature to obtain a plastic depolymer, the plastic depolymer comprising waste synthetic composite fibers; (b) mixing the plastic depolymer with a first polyether polyol and polymerizing it at a second temperature to obtain a polymeric diol mixture; (c) mixing the polymeric diol mixture, a second polyether polyol, a polyisocyanate, and a solvent, and reacting them at a third temperature to obtain a recycled plastic having urethane groups; and (d) coating and heating the recycled plastic having urethane groups to obtain the non-porous film, wherein... The thickness of the non-porous membrane ranges from 10 to 30 μm, and the weight ranges from 10 to 30 g / m2. The water pressure resistance of the non-porous membrane is greater than 10,000 mmH2O when tested by JIS L1092B, and the moisture permeability of the non-porous membrane is greater than 120,000 g / m2‧24 h when tested by JIS L1099B1.

10. A method for preparing a microporous membrane, comprising the following steps: (a) mixing a waste plastic mainly composed of polyterephthalate and polyurethane with a depolymerizing agent, and depolymerizing the waste plastic at a first temperature to obtain a plastic depolymer, the plastic depolymer comprising waste synthetic composite fibers; (b) mixing the plastic depolymer with a first polyether polyol and polymerizing it at a second temperature to obtain a polymeric diol mixture; (c) mixing the polymeric diol mixture, a second polyether polyol, a polyisocyanate, and a solvent, and reacting them at a third temperature to obtain a recycled plastic having urethane groups; and (d) coating, coagulating, washing, and heating the recycled plastic having urethane groups to obtain the microporous membrane, wherein... The thickness of the microporous membrane ranges from 30 to 90 μm, and the weight ranges from 10 to 30 g / m2. The water pressure resistance of the microporous membrane is greater than 10000 mmH2O as tested by JIS L1092B, and the moisture permeability of the microporous membrane is greater than 3000 g / m2‧24 h as tested by JIS L1099A1.

11. A method for producing a composite fabric, comprising the following steps: (a) mixing a waste plastic mainly composed of polyterephthalate and polyurethane with a depolymerizing agent, and depolymerizing the waste plastic at a first temperature to obtain a plastic depolymer, the plastic depolymer comprising waste synthetic composite fibers; (b) mixing the plastic depolymer with a first polyether polyol and polymerizing it at a second temperature to obtain a polymeric diol mixture; (c) mixing the polymeric diol mixture, a second polyether polyol, a polyisocyanate and a solvent, and reacting it at a third temperature to obtain a recycled plastic having urethane groups; (d) coating and heating the recycled plastic having urethane groups to obtain a non-porous film; and (e) attaching a base fabric to the non-porous film to obtain the composite fabric.

12. A method for producing a composite fabric, comprising the following steps: (a) mixing a waste plastic mainly composed of polyterephthalate and polyurethane with a depolymerizing agent, and depolymerizing the waste plastic at a first temperature to obtain a plastic depolymer, the plastic depolymer comprising waste synthetic composite fibers; (b) mixing the plastic depolymer with a first polyether polyol and polymerizing it at a second temperature to obtain a polymeric diol mixture; (c) mixing the polymeric diol mixture, a second polyether polyol, a polyisocyanate and a solvent, and reacting it at a third temperature to obtain a recycled plastic having urethane groups; (d) coating, coagulating, washing and heating the recycled plastic having urethane groups to obtain a microporous film; and (e) attaching a base fabric to the microporous film to obtain the composite fabric.