Process for manufacturing components from shredded polymer-coated paper products

Abstract

The invention relates to a process for producing a thermoformable and/or embossable particle/polymer composite using a substrate S based on shredded polymer-coated paper and a thermoplastic polymer P, therewith providing a new method of recycling/upcycling paper waste. Furthermore, a process for the manufacturing of a molded article obtained from the paper-based particle/polymer composite and its use as an element in buildings or in furniture are disclosed.

Claims

1-15. (canceled)

16: A process of manufacturing a particle/polymer composite, comprising (i) providing a particulate substrate S comprising a. shredded polymer-glued or polymer-coated paper products and b. at least one polymer P, (ii) introducing the particulate substrate S into a gas stream, (iii) contacting the particulate substrate S with an aqueous dispersion or solution of the polymer P having a glass transition temperature Tg.sup.P in the gas stream, (iv) drying and depositing the particulate substrate S contacted with the polymer P in the gas stream, (v) transferring the obtained deposited polymer-contacted substrate into (a) a layer, (b) a floor or (c) into a mold, and (vi) densifying the polymer-contacted substrate at a temperature greater than or equal to Tg.sup.P to form a particle/polymer composite, wherein (a) substrate S comprises shredded polymer-glued or polymer-coated paper products; and (b) the at least one polymer P is thermoplastic and has a Tg.sup.P≥−20° C. measured according to DIN EN ISO 11357-2 (2013-09).

17: The process according to claim 16, further comprising: introducing into the gas stream and contacting with the polymer P, a substrate S.sub.b comprising shredded biomaterials.

18: The process according to claim 17, wherein the shredded biomaterials are selected from the group consisting of bamboo, miscanthus or wood particles, and combinations thereof.

19: The process according to claim 16, wherein providing the particulate substrate S comprises shredding, cutting, chopping, milling, or crushing paper products, wherein the paper products comprise a polymer-based glue and/or a polymer-coating.

20: The process according to claim 16, wherein the polymer-glued or polymer-coated paper products are selected from polymer-coated disposable paper products, polymer-coated paper take-away cups, polymer-coated paper dishes, polymer-coated paper bowls, polymer-coated paper bags, polymer-coated paper beverage cartons and polymer-coated paper packages.

21: The process according to claim 16, wherein the polymer P does not comprise intentionally added formaldehyde or structural moieties derived from formaldehyde.

22: The process according to claim 16, wherein the at least one polymer P is present in the form of an aqueous dispersion of the polymer P having a film forming temperature <Tg.sup.P.

23: The process according to claim 16, wherein the weight ratio of substrate S to polymer P is ≥2 and ≤50.

24: The process according to claim 16, wherein the paper-based particle/polymer composite obtained is in the form of a sheet and has a basis weight ≥500 and ≤30 000 g/m.sup.2.

25: The process according to claim 16, wherein the densification results in an increase in the density of the obtained paper-based particle/polymer composite of up to 20-fold.

26: The process according to claim 16, wherein the densification results in the obtained paper-based particle/polymer composite having a density of 0.30 to 0.98 g/cm.sup.3.

27: The paper-based particle/polymer composite obtained by a process according to claim 16.

28: The paper-based particle/polymer composite obtained by a process according to claim 17.

29: The paper-based particle/polymer composite obtained by a process according to claim 26.

30: The process according to claim 16, further comprising: forming a molded article, wherein the thermoformable and/or embossable paper-based particle/polymer composite according to step (v) is heated to a temperature ≥TgP, brought into the desired shape and/or surface structure to obtain a shaped and/or surface-structured paper-based particle/polymer molding, which is then cooled to a temperature <TgP while retaining the formed shape and/or surface structure.

31: The process according to claim 16, further comprising a step of forming a molded article, wherein the thermoformable and/or embossable paper-based particle/polymer composite according to step (v) is heated to a temperature Tg.sup.P brought into the desired shape and/or surface structure together with a support structure and/or a protective layer made of HPL, CPL, melamine resin overlay or other usual wear/protective layers from wood-based materials industry to obtain a shaped and/or surface-structured paper-based particle/polymer molding with wear and/or protective layers which is then cooled to a temperature <Tg.sup.P while maintaining its shape and/or surface structure.

32: A molded article obtainable by the process according to claim 30.

33: A molded article obtainable by the process according to claim 31.

34: A structure selected from the group consisting of wall panels, room dividers, floors, counters, and furniture, said structure comprising the molded article of claim 32.

35: A structure selected from the group consisting of wall panels, room dividers, floors, counters, and furniture, said structure comprising the molded article of claim 33.

Description

DESCRIPTION OF THE FIGURES

[0119] FIGS. 1 to 3 show exemplary embodiments of molded articles according to the invention laminate structures for articles molded bodies according to the invention made with the paper-based particle/polymer composite of the invention.

[0120] FIGS. 4 to 6 show density profiles of embodiments according to the Examples below (test pieces PC_01, PC_02 and PC_03).

[0121] FIG. 7 shows the density profile of a laminated test piece according to the invention (PC_L_01).

EXAMPLES

Example 1

[0122] The tests were carried out with a 12 inch refiner from Antriz and a blowline connected to it. The refiner was operated at 130-140° C. and an internal pressure of 3-4 bar (gauge pressure). The distance between the two grinding plates was 1.0 mm, and one of the grinding plates was operated at 3000 rpm. The blowline (steel pipe) connected to the refiner via a flange had an inner diameter of 3 cm and a pipe length of 30 m. The aqueous dispersion of the polymer P (binders) were then injected into the blowline at 2 bar (overpressure) via a 0.2 mm nozzle mounted on the blowline at a distance of 50 cm from the refiner outlet/blowline inlet. At the end of the blowline a cyclone separator was located through which the particulate substrate S contacted with the polymer P (i.e. the polymer-contacted substrate) were dried and cooled to a temperature of approx. 80° C. and separated into an open container.

[0123] Shredded polymer-glued or polymer-coated waste paper products were pretreated with 130-140° C. hot water/steam at 3-4 bar overpressure in the digester and used for the tests, and the mass flow rate of the pretreated shredded waste paper (particulated polymer-glued/polymer-coated paper) into the refiner (or into the blowline) was set at 30 kg per hour.

[0124] The dispersion acForm® 2888 (BASF) (a modified polyacrylate) was used as binder. The binder was injected into the blowline by means of an eccentric screw pump at a pressure of 2 bar (overpressure) via the 0.2 mm nozzle(s), the mass flows being adjusted to 5.3 kg binder (calculated as solid) and 10.6 kg (as 50% solids dispersion) per hour. The test was carried out for 1 hour in continuous steady state, during which time the shredded paper particles were contacted (sprayed) with the binder and collected in an open container.

[0125] Investigation of the mechanical properties of compressed boards (molded articles obtained from the paper-based particle/polymer composite prepared in the blowline process described above)

[0126] With the shredded and polymer (binder)-contacted paper particles obtained from the blowline according to the aforementioned experimental procedure, sheets of 22×22 cm format and different thicknesses and densities were produced: [0127] 1. 22×22 cm and 7.5 mm thickness with a density of 0.72 g/cm.sup.3 [0128] 2. 22×22 cm and 8.0 mm thickness with a density of 0.81 g/cm.sup.3 [0129] 3. 22×22 cm and 3.6 mm thickness with a density of 0.93 g/cm.sup.3

[0130] For this purpose, 260, 305 and 165 g, respectively, of the shredded and polymer (binder)contacted paper particles obtained in the blowline were evenly sprinkled into a horizontally positioned wooden frame with the internal dimensions 22×22×30 cm (L/W/H). A 22×22 cm wooden plate was then placed horizontally on top of the so obtained layer or floor of the shredded and polymer (binder)-contacted paper particles in the wooden frame and pre-compacted with a central stamp. The pre-compacted layer or floor of the shredded and polymer (binder)-contacted paper particles thus obtained was then removed from the wooden frame, covered on both square surfaces with a release paper and compacted to the target thickness/density between two 3 mm thick horizontal press plates at 180° C. under pressure with a pressing time factor of 12 seconds per millimeter, the lower side of the pre-compacted layer or floor being placed on the lower horizontal press plate in each case. Subsequently, the obtained compressed paper-particle plates (sheets or boards) were allowed to cool to room temperature outside the press.

[0131] The resulting paper-particle sheets (plates or boards) are designated as test pieces PC_01, PC_02 and PC_03, respectively, depending on the target thickness as well as the target density.

[0132] The following tests were carried out with the obtained paper-particle sheets: Determination of e-modulus (modulus of elasticity), water absorption after 24 h, thickness swelling after 24 h (according to DIN EN 316) and a density profile measured (apparatus Labor-Dichteprofilmessanlage DA-X5, GreCon).

[0133] The modulus of elasticity was determined in accordance with the ISO 178 standard. The results obtained with the various thicknesses and densities of the test pieces are listed in Table 1:

TABLE-US-00001 TABLE 1 Test Piece PC_01 PC_02 PC_03 Thickness mm 7.65 80.9 3.65 Density g/cm.sup.3 0.72 0.81 0.93 Water absorption 24 h % 129 113 76 Thickness swelling 24 h % 50 54 47 e-module according to ISO 178 Wide mm 15.87 15.89 15.74 Support width mm 120 130 74 Bending e-module N/mm.sup.2 1071 2050 2685

[0134] The density profiles of the test pieces PC_01, PC_02 and PC_03 are shown in the FIGS. 4, 5 and 6.

[0135] Production of semi-finished products and laminates thereof

[0136] According to the procedure described above, two more paper particle sheets, PC_HZ_01 and PC_HZ_02 were prepared from 265 g of shredded and polymer (binder)-contacted paper particles each:

[0137] PC_HZ_01: 22×22×0.7 cm; density: 0.78 g/cm.sup.3

[0138] PC_HZ_01: 22×22×0.65 cm; density: 0.83 g/cm.sup.3

[0139] In a further process step, the semi-finished products produced in this way were pressed together with impregnated core papers and a decorative paper, with the semi-finished products being further compressed at the same time. The laminates were produced by placing 3 layers of core paper (250 g/m.sup.2 each) and a decorative paper (220 g/m.sup.2) on the top and bottom of each of the paper-particle sheet semi-finished products and then pressing this structure together in the press at 140° C. within 180 seconds. The obtained laminated paper-particle sheets were then allowed to cool outside the press between two 10 mm aluminum plates. These laminates are designated as test pieces PC_L_01 and PC_L_02.

[0140] The following tests were carried out with the obtained paper-particle sheet laminates: Determination of e-modulus (modulus of elasticity), flexural strength, transverse tensile strength, water absorption after 24 h, thickness swelling after 24 h and a density profile measured. The results obtained with the laminated test pieces are listed in Table 2:

TABLE-US-00002 TABLE 2 Test Piece PC_L_01 PC_L_02 Thickness mm 7.57 7.49 Density g/cm.sup.3 1.07 1.02 Water absorption 24 h % 18 26 Thickness swelling 24 h % 0.6 2.4 e-module according to ISO 178 Wide mm 15 15 Support width mm 122 120 Bending e-module N/mm.sup.2 6453 6468 Flexural strength N/mm.sup.2 70 70 Transverse tensile strength Force Max. N 3245 3110 Tensile stress Max. N/mm.sup.2 1.286 1.221

[0141] The density profile of the laminated test piece PC_L_01 is shown in FIG. 7.

Example 2

[0142] Preparation of Test-Items Using Substrates of Shredded Coated Paper Shredded Wood (Paper/Wood Mixtures) with Thermoplastic Binder

[0143] Raw Materials:

[0144] Substrate S.sub.p: coated paper

[0145] Substrate S.sub.b: spruce wood

[0146] Binder: acForm 2889

[0147] Impregnation Process: Blowline

[0148] Process Description:

[0149] Similar as described in Example 1, shredded paper and the spruce wood particles are processed on a blowline with the thermoplastic binder.

[0150] Therein, the substrates S.sub.p and S.sub.b are contacted with the thermoplastic binder, dried and deposited separately.

[0151] The ratio of the respective substrate and the binder is adjusted to 85% substrate and 15% binder, each by weight.

[0152] Drying of the binder-impregnated substrates is adjusted to 8% residual moisture.

[0153] In a subsequent step the dried and deposited binder-impregnated substrates are admixed to form a blend using a blender.

[0154] The following binder-impregnated compositions (blends) are prepared:

TABLE-US-00003 TABLE 3 Mixture/ Blend No. Substrate S.sub.p Substrate S.sub.b Binder 1 100%  0 acForm 2889 2 75% 25% acForm 2889 3 50% 50% acForm 2889 4 25% 75% acForm 2889 5 10% 90% acForm 2889 6 0 100%  acForm 2889

[0155] The mixtures/blends No. 1 to 6 are used to prepare test boards.

[0156] Board Processing:

[0157] The mixtures/blends No. 1 to 6 are evenly scattered into a frame box of 22×22 cm, pre-compressed and then compressed at 180° C. to a thickness of 4 mm with a press time factor of 15 sec./mm board thickness. The resulting density is about 0.95 g/cm.sup.3.

[0158] The obtained test boards are then evaluated with respect to their physical properties as listed in Table 4 and 5:

TABLE-US-00004 TABLE 4 Mixture/ Scatter Board Board Board Blend Board weight weight thickness Density No. No. [g] [g] [mm] [g/cm.sup.3] 1 1 200 192 4.2 0.94 2 2 200 193 4.1 0.97 3 3 200 190 4.1 0.96 4 4 200 191 4.1 0.96 5 5 200 192 4.2 0.94 6 6 200 192 4.2 0.94

TABLE-US-00005 TABLE 5 Board No. Unit 1 2 3 4 5 6 e-Module N/mm.sup.2 2500 2912 3281 3487 3520 3598 deviation N/mm.sup.2 612 567 358 413 601 629 bending stress N/mm.sup.2 29 36 40 52 54 58 deviation N/mm.sup.2 7 6 9 12 14 18 Water % 31 32 31 33 35 34 swelling 24 h deviation % 2 2 1 1 2 1