A FLEXIBLE FOAMING PROCESS FOR PRODUCING THERMALLY INSULATED ARTICLES

Abstract

A flexible discontinuous process produces a series of at least two articles containing thermally insulating polyurethane foam from at least three streams (A), (B) and (C). The process involves mixing the at least three streams with different mixing ratios and injecting the mixture into cavities of the articles. A production unit can be used for performing this process.

Claims

1: A discontinuous process for producing a series of at least two articles containing thermally insulating polyurethane foam from at least a stream (A) comprising at least one isocyanate reactive compound, a stream (B) comprising at least one organic polyisocyanate, and a stream (C) comprising at least one compound selected from the group consisting of isocyanate reactive compounds, organic polyisocyanates, catalysts, blowing agents, chain extenders, stabilizers, crosslinkers, flame retardants, and additives, wherein stream (C) is different from both streams (A) and (B); wherein the process comprises: (a) producing at least one first article containing a first thermally insulating polyurethane foam by (a1) providing a first polyurethane reaction mixture in a mixing device (MD) by mixing at least two of streams (A), (B), and (C); (a2) injecting the first polyurethane reaction mixture provided in (a1) into a cavity of the at least one first article and forming the first thermally insulating polyurethane foam; and (b) producing at least one second article containing a second thermally insulating polyurethane foam by (b1) providing a second polyurethane reaction mixture in the mixing device (MD) by mixing at least two of streams (A), (B), and (C); (b2) injecting the second polyurethane reaction mixture provided in (b1) into a cavity of the at least one second article and forming the second thermally insulating polyurethane foam; wherein a mixing ratio of streams (A), (B), and (C) in (a1) is different from a mixing ratio of streams (A), (B), and (C) in (b1), wherein the amount of stream (C) may be zero either in (a1) or in (b1), and wherein in case the amount of stream (C) is not zero in (a1) or (b1), an amount of either stream (A) or (B) may be zero.

2: The process according to claim 1, wherein the at least one first article and the at least one second article differ in at least one physical and/or chemical property.

3: The process according to claim 1, wherein each of the first thermally insulating polyurethane foam and the second thermally insulating polyurethane foam is a rigid closed-cell polyurethane foam.

4: The process according to claim 1, wherein the at least one first article and the at least one second article are each selected from the group consisting of refrigerators; freezers; insulating boxes for cold and hot goods; water heaters; hot water storage tanks; insulation boards; and pipes.

5: The process according to claim 1, wherein in (a1) and/or (b1), the streams (A), (B), and (C) are fed simultaneously into the mixing device (MD), or wherein in (a1) and/or (b1), two of the streams (A), (B), and (C) are premixed and fed into the mixing device (MD) simultaneously with a remaining stream of the streams (A), (B), and (C).

6: The process according to claim 1, wherein in (a1) and (b1), the streams (A), (B), and (C) are provided from separate reservoirs for each of streams (A), (B), and (C), respectively, wherein each of the separate reservoirs are connected with the mixing device (MD) during (a1) and (b1).

7: The process according to claim 1, wherein in (a1) and/or (b1), an amount of each of streams (A), (B), and (C) is not zero.

8: A computer implemented process for producing a series of at least two articles containing thermally insulating polyurethane foam, the process comprising: performing the process according to claim 1 with a control unit, wherein mixing ratios in (a1) and (b1) are controlled by the control unit which is configured to control the feeding of the streams (A), (B), and (C) in (a1) and (b1) into the mixing device (MD).

9: The computer implemented process according to claim 8, wherein the control unit is programmed to repeat (a) with a first predefined mixing ratio for a first predefined number of times and to repeat (b) with a second predefined mixing ratio for a second predefined number of times.

10: The computer implemented process according to claim 8, wherein information about the at least one first article and the at least one second article is provided to the control unit by a sensor reading a sensor readable information tag provided with the at least one first article and the at least one second article, and/or wherein information about ambient conditions of production is provided to the control unit by a sensor for detecting the information about the ambient conditions of production.

11: The computer implemented process according to claim 10, wherein the sensor readable information tag is a RFID (radio-frequency identification) chip or a 2D code.

12: The computer implemented process according to claim 10, wherein the sensor for detecting the information about the ambient conditions of production detects at least one ambient condition parameter selected from the group consisting of temperature, humidity, and air pressure.

13: The computer implemented process according to claim 10, wherein the information about the at least one first article and the at least one second article and/or the information about the ambient conditions of production provided to the control unit either contains the mixing ratio of the streams (A), (B), and (C), or is aligned with data about the mixing ratio from a data base for determining the mixing ratio; and wherein the control unit adjusts the feeding of the streams (A), (B), and (C) into the mixing device (MD) in (a1) and (b1) according to the mixing ratio.

14: A production unit for producing a series of at least two articles containing thermally insulating polyurethane foam according to the computer implemented process according to claim 8, the production unit comprising: the mixing device (MD); separate reservoirs for each of the streams (A), (B), and (C) connected with the mixing device (MD); a mold carrier for the housing of the at least one first article and the at least one second article; and the control unit configured to control the feeding of the streams (A), (B), and (C) into the mixing device (MD) from the reservoirs for each of the streams (A), (B), and (C), wherein the control unit controls mixing ratios of the streams (A), (B), and (C) in (a1) and (b1) into the mixing device (MD), so that the mixing ratio of streams (A), (B), and (C) in (a1) is different from the mixing ratio of streams (A), (B), and (C) in (b1).

15: The production unit according to claim 14, further comprising a sensor for reading sensor readable information tags and/or a sensor for detecting ambient conditions of production.

16: The production unit according to claim 15, wherein the production unit comprises an access to a data base containing information for determining the mixing ratios of the streams (A), (B), and (C) to be fed in the mixing device (MD) based on information provided by the sensor for reading sensor readable information tags from sensor readable information tags and/or from the sensor for detecting ambient conditions of production.

17. (canceled)

18: A non-transitory computer-readable medium, having stored thereon instructions to execute the computer implemented process according to claim 8, wherein the non-transitory computer-readable readable controls a production unit comprising: the mixing device (MD); separate reservoirs for each of the streams (A), (B), and (C) connected with the mixing device (MD); a mold carrier for the housing of the at least one first article and the at least one second article; and the control unit configured to control the feeding of the streams (A), (B), and (C) into the mixing device (MD) from the reservoirs for each of the streams (A), (B), and (C), wherein the control unit controls mixing ratios of the streams (A), (B), and (C) in (a1) and (b1) into the mixing device (MD), so that the mixing ratio of streams (A), (B), and (C) in (a1) is different from the mixing ratio of streams (A), (B), and (C) in (b1).

19: The computer implemented process according to claim 11, wherein the 2D code is at least one selected from the group consisting of a QR (quick response) code, a variant of a QR code, a data matrix, an Aztec code, a JAB (just another bar code) code, and a bar code.

Description

EXAMPLES

[0121] Examples E1 to E3 were prepared from three streams (A), (B) and (C) directly one after another in one mixing device (MD) by changing the mixing ratios of streams (A), (B) and (C) according to the invention resulting in a process comprising steps (a), (b) and a further step (c) wherein a third article is produced. For each example E1 to E6 2 sample articles were produced and used as test specimens. Examples E4, E5 and E6 were conducted separately to demonstrate different streams (A), (B) and (C) which can be used to conduct the process as described above resulting in polyurethane foams with different properties.

[0122] Polyols, isocyanates, blowing agents, additives and other raw materials

Polyols A to E:

[0123] Polyol A: Polyetherpolyol based on sucrose, glycerine and propylene oxide (PO); OH-value of 427 mg KOH/g; functionality: 6.0 [0124] Polyol B: Polyetherpolyol based on vic-TDA and PO; OH-value of 399 mg KOH/g; functionality: 3.9 [0125] Polyol C: Polyetherpolyol based on vic-TDA, ethylene oxide (EO) and PO; OH-value of 160 mg KOH/g; functionality: 3.9 [0126] Polyol D: Polymer polyol based on styrene and acrylonitrile (ratio 2:1, styrene:acrylonitrile; (SAN polymer polyol) derived from a polyether polyol based on glycerine, PO and EO (OH-value of 56 mg KOH/g, functionality=2.7); solid content of 45 wt.-%; OH-value of 30 mg KOH/g (c.f. Ionescu's Chemistry and Technology of Polyols and Polyurethanes, 2nd Edition, 2016 by Smithers Rapra Technology Ltd). SAN polymer polyols are available under the tradename, such as but not limited to, Lupranol® from BASF. [0127] Polyol E: Polyether ester polyol based on sucrose, glycerol, PO and biodiesel, OH-value of 420 mg KOH/g; functionality: 4.5

Surfactant F:

[0128] Silicon surfactant Tegostab® B 84204 from Evonik

Catalyst Mixture G:

[0129] containing

[0130] Catalyst G1): Dimethylcyclohexylamine

[0131] Catalyst G2): Bis(2-dimethylaminoethyl)ether

[0132] Catalyst G3): Tris(dimethylaminopropyl)hexahydro-1,3,5-triazine or Potassium acetate

[0133] Catalyst G4): Dimethylbenzylamine

Blowing Agents:

[0134] CP95: Cyclopentane 95—cyclopentane with a purity >95%; e.g. from Haltermann Carless

[0135] HCFO-1233zd: e.g. Solstice LBA from Honeywell

[0136] HFO-1336mzz: e.g. Opteon 1100 from Chemours

Isocyanate H:

[0137] Polymer-MDI with content of 31.5 wt.-% (Lupranat® M20S from BASF)

Analytical Methods Used

[0138] Water content by DIN 51777 [0139] OH value by DIN 53240 [0140] Amine value by DIN 16945 [0141] NCO content by DIN EN ISO 14896

Thermal Conductivity

[0142] Thermal conductivity was determined using a Taurus TCA300 DTX at a midpoint temperature of 10° C. To prepare the test specimens, the polyurethane reaction mixture was imported into a 2000×200×50 mm mold with 1517.5% overpacking and demolded 4.5 min later. After aging for 24 hours under standard conditions, several foam cuboids (at positions 10, 900 and 1700 mm on the lower end of the Brett molding) measuring 200×200×50 mm are cut out of the center. The top and bottom sides were then removed to obtain test specimens measuring 200×200×30 mm.

Determination of Demolding Behaviour

[0143] Demolding behaviour was determined by measuring the postexpansion of foam bodies produced using a 700×400×90 mm box mold at a mold temperature of 45±2° C. as a function of demolding time and the degree of overpacking (OP), which corresponds to the ratio of overall apparent density/minimum fill density. Postexpansion was determined by measuring the foam cuboids after 24 h. The post-expansion depicts the swelling of the foam block in mm.

Minimum Fill Density for a Component Part/Free Rise Density

[0144] Minimum fill density was determined by importing just a sufficient amount of polyurethane reaction mixture into a mold measuring 2000×200×50 mm at a mold temperature of 45±2° C. to just fill the mold. Free rise density was determined by allowing the foaming polyurethane reaction mixture to expand in a plastic bag at room temperature. The density was determined on a cube removed from the center of the foam-filled plastic bag.

General Procedure for Preparing the Reaction Mixture

[0145] A blowing agent was added to component A) and/or C). A TopLine HK 650/650/45P high pressure mixing device MT18-4 from Hennecke GmbH, operating at an output rate of 250 g/s was used to mix the components A) and C), which (one and/or both) have been admixed with the blowing agents, with the requisite amount of the component B), to obtain a desired mixing ratio. The temperature of components A), B) and C) were 20° C., while that of component C) was 30° C. in case of E5.

[0146] The reaction mixture was subsequently injected into molds, temperature regulated to 40° C., measuring 2000 mm×200 mm×50 mm and/or 400 mm×700 mm×90 mm and allowed to foam up therein. Overpacking was 14.5%, i.e., 14.5% more reaction mixture than needed to completely foam out the mold was used.

[0147] The results are shown in tables 1a and 1b. The amounts of the compounds are given in parts by weight (pbw). The composition of streams (A) and (B)) is the same in the examples E1 to E6. The compositions of streams (A) and (B) are also the same in examples E7-E10. The composition of stream (C) is the same in examples E2 and E3, but different in examples E4, E5 and E6. The composition of stream (C) is the same in examples E7-E10, but different from those in E1-E6. In examples E1 and E7, the amount of stream (C) is zero. Each example E1 to E10 could be regarded as a representative of a step (a1), (b1) or (c1) wherein a third article is produced by using a third mixing ratio. By combining suited examples E1 to E10 it becomes clear that different polyurethane foams can be obtained by just varying the mixing ratio of the streams (A), (B) and (C).

[0148] E.g. the combination of the three examples E1, E2 and E3 as well as the combination of examples E7, E8, E9, and E10 represent processes in which in step (a1), (b1) and (c1) streams (A), (B) and (C) are used in different mixing ratios. Namely for E1-E3, A:C:B is 100:0:127, 80:20:124, and 65:35:122, respectively, resulting in polyurethane foams with different thermal conductivities and post expansion values. Example E1 does not contain fluorinated blowing agents. Fluorinated blowing agents are usually more expensive than cyclopentane but result in a lower thermal conductivity. On the other hand, fluorinated blowing agents may interact undesirably with materials used for the casing, liner etc. In a similar way examples E1 and E4, E1 and E5 or examples E1 and E6 could be combined in a process according to the present invention yielding different polyurethane foams by varying the mixing ratios of streams (A), (B), and (C). For E7-E10, the respective mixing ratios are A:C:B is 100:0:131, 70:30:130, 30:70:128 and 0:100:128, respectively. In those cases, the formulations show different reactivities, so that the gel times of the systems can also be controlled via the mixing ratios of streams (A), (B), and (C).

TABLE-US-00001 TABLE 1a E1 E2 E3 E4 E5 E6 Stream A Polyol A 42.4 42.4 42.4 42.4 42.4 42.4 Polyol B 29.1 29.1 29.1 29.1 29.1 29.1 Polyol C 8.2 8.2 8.2 8.2 8.2 8.2 Propylencarbonat 1.8 1.8 1.8 1.8 1.8 1.8 Silicon surfactant F 2.6 2.6 2.6 2.6 2.6 2.6 Catalyst mixture G 2.1 2.1 2.1 2.1 2.1 2.1 CP95.sup.a 11.9 11.9 11.9 11.9 11.9 11.9 H.sub.2O 2.0 2.0 2.0 2.0 2.0 2 Stream C Polyol A 35.7 35.7 35.7 37.9 14.7 Polyol B 28.0 28.0 28.0 26.0 34.0 Polyol D 89.5 23.4 Propylencarbonat 1.8 1.8 1.8 1.8 1.8 1.6 Silicon surfactant F 2.6 2.6 2.6 2.6 2.6 3.4 Catalyst mixture G 2.1 2.1 2.1 2.3 2.1 9.6 H.sub.2O 2.0 2.0 2.0 1.6 4.0 2.2 HFO-1336mzz 27.8 27.8 27.8 HFCO-1233zd 27.8 CP95.sup.a 11.1 Stream B Isocyanate H 100 100 100 100 100 100 Mixing ratio A:C:B 100:0:127 80:20:124 65:35:122 65:35:120 90:10:122 80:20:127 Results from 3-component machine processing Start time [s] 4 4 3 4 4 3 Gel time [s] 40 41 40 42 38 28 Free rise density [g/L] 23.3 22.8 23 23.1 24.5 23.3 Minimum filling 31.3 30.2 30 30.1 32.0 31.1 density [g/L] Post Expansion [mm] with 17.5% overpacking 3 min 3.7 3.2 2.3 3.8 3.1 3.1 4 min 2.2 1.8 1.6 2.4 1.8 2.2 5 min 1.3 1.1 0.8 1.3 1.0 1.5 compressive strength 0.159 0.166 0.161 0.164 0.154 0.172 [N/mm2]; density: 35.5 g/L Thermal conductivity 19.5 19.1 18.7 18.8 19.7 19.6 [mW/mK]

TABLE-US-00002 TABLE 1b E7 E8 E9 E10 Stream A Polyol A 39.9 39.9 39.9 39.9 Polyol B 27.3 27.3 27.3 27.3 Polyol C 7.0 7.0 7.0 7.0 Polyol E 6.2 6.2 6.2 6.2 Propylencarbonat 1.3 1.3 1.3 1.3 Silicon surfactant F 2.4 2.4 2.4 2.4 Catalyst mixture G 1.9 1.9 1.9 1.9 CP95.sup.a 11.9 11.9 11.9 11.9 H.sub.2O 2.1 2.1 2.1 2.1 Stream C Polyol A 36.9 36.9 36.9 36.9 Polyol B 26.4 26.4 26.4 26.4 Polyol C 6.1 6.1 6.1 6.1 Polyol E 8.8 8.8 8.8 8.8 Propylencarbonat 1.8 1.8 1.8 1.8 Silicon surfactant G 2.8 2.8 2.8 2.8 Catalyst mixture G 3.2 3.2 3.2 3.2 CP95.sup.a 11.9 11.9 11.9 11.9 H.sub.2O 2.1 2.1 2.1 2.1 Stream B Isocyanate H 100 100 100 100 Mixing ratio A:C:B 100:0:131 70:30:130 30:70:128 0:100:128 Results from 3-component machine processing Start time [s] 4 4 3 2 Gel time [s] 40 34 29 26 Free rise density [g/L] 22.8 23.6 23.1 22.1 Minimum filling 30.3 31.3 30.5 29.7 density [g/L] Post Expansion [mm] with 17.5% overpacking 3 min 3.3 3.2 3.0 2.6 4 min 1.8 1.8 2.1 1.9 5 min 1.1 1.2 1.2 1.2 compressive strength 0.177 0.167 0.170 0.187 [N/mm2]; density: 36.0 g/L Thermal conductivity 19.6 19.4 19.4 19.3 [mW/mK]