Process and apparatus for separating no2 from a co2 and no2-containing fluid

Description

[0001] The present invention relates to a method and an apparatus for separating a gaseous mixture containing carbon dioxide as the main component. It relates in particular to methods and apparatus for purifying carbon dioxide, for example derived from the combustion of a carbonaceous fuel, such as is the case in a fossil fuel or biomass oxy-fired power plant.

[0002] The combustion of carbonaceous fuels produces CO2 and gases such as SO2, SO3 and NOx which pollute the atmosphere and which contribute greatly to the greenhouse effect - especially CO2. These CO2 emissions are concentrated in four main sectors: power generation, industrial processes, transport, and residential and commercial buildings. Most of the CO2 emissions to the atmosphere from electricity generation and industrial sectors are currently in the form of combustion off-gases, where CO2 concentrations are typically 4-14 vol.% For combustion with air or up to 60-70 vol.% For oxygen combustion, although CO2 it is produced in high concentrations by a number of industrial processes.

[0003] In principle, waste gases can be cleaned and stored, in which case they would have to be compressed to a pressure of typically greater than 100 bar abs, a pressure that would consume an excess amount of energy. The off-gas CO2 recovery and purification systems are sometimes referred to as CO2 purification units or CPUs. For these reasons, it is advantageous to produce a CO2 stream of relatively high purity for transportation, on-site consumption or storage. This carbon dioxide can be used to recover enriched oil or simply injected into depleted gas and oil reservoirs or aquifers.

[0004] Among the numerous problems with CO2 capture today, the purity of CO2 sent for sub-surface storage (EOR or geological sequestration) is one of the more delicate issues to be solved. This is due to the enormous difficulties in clearly understanding and modeling the interactions between subsurface elements and injected gases, as well as corrosion of pipelines.

[0005] One type of acid gas commonly found in CO2 captured from off-gas is NOx. By NO x is meant one or more oxides of nitrogen including NO, N2O, N2O4 and NO2 and N2O3. Below 158 ° C, NO2 is in equilibrium with its N2O4 polymer / dimer where the lower the temperature, the higher the N2O4 concentration is compared to NO2. In this document, the word NO2 means not only NO2 but also its polymer / dimer N2O4 at equilibrium.

[0006] The NOx compounds are not necessarily removed by the CPU process. However, some applications require NOx free CO2.

[0007] Some have proposed to remove NOx from waste gas using a De-NOx column by separating NO2 from CO2 because the critical temperature of NO2 is higher than the temperature of CO2. The use of the De-NOx column continues to be a challenge for the bottom NO2 enriched fluid. For example, in US 7,708,804 it is proposed to use a De-NOx column in which the NO2-enriched liquid from the bottom of the De-NOx column is processed in one of three ways. First, it can be returned to the compressor inlet. Second, it can be sent to a wash column. Third, it can be burned using a burner connected to the boiler (which itself can be the source of the waste gas) in an attempt to reduce NO2 to N2.

[0008] Regarding the first technique, it is disadvantageous to recycle NO2-enriched fluid at the compressor inlet. Since the recycle stream may be about 5-10% of the total compressed and downstream treated flow, the compressor and downstream equipment must be 5-10% larger than would be necessary if the NO2-enriched stream, on the contrary, was not recycled. The required compression energy would also increase by 5% to 10%. In addition, a relatively higher content of acid gas in the compressed off-gas will result in the production of more acid gas condensate in the compressors. Therefore, compressors and dryers will be subjected to a more severe acid attack compared to the absence of a NO2 recycle stream. This more severe acid attack may lead to a shorter service life of the compressors or may require the compressor to be constructed from a more expensive material that is sufficiently resistant to such acid fluids. Dryers are expected to experience similar negative effects due to the presence of acid gas. Finally, in order to reduce the amount of NO2 recycled to the compressor, the recycle flow rate to the De-NOx column may be reduced. However, a reduction in the recycle flow rate into the De-NOx column may soon cause the column to exceed its wettability limit. This will lead to unsatisfactory drops in distillation efficiency.

[0009] Thus, one object of the invention is to provide a method and system for purifying CO2 from exhaust gases that does not require recycling of NO2-enriched fluid to a site prior to the purification process.

[0010] Regarding the second technique, the use of a scrubbing column would result in a significant CO2 loss in the event that the washed stream was not recycled at the CPU inlet. If, on the contrary, the washed stream is recirculated to the CPU inlet, significant CO2 losses can be avoided. However, this has the same disadvantage as above in terms of increasing the size of the compressor and downstream apparatus to accommodate the increased flow rate.

[0011] It is therefore another object of the invention to provide a method and system for purifying CO2 from off-gases that does not require a scrubbing column to remove NO2 from the bottom of the De-NOx column.

[0012] With regard to a third technique, reducing NO2 in the burner flame to scale of the NO2-enriched stream from the De-NOx column is a technically very difficult problem. Regardless of the relative state of development of this approach, the reduction of NOx in the burner flame still results in significant CO2 losses.

[0013] It is therefore an object of the invention to provide a more reliable method for the production of a CO2 product after off-gas treatment, which contains an acceptably low amount of NOx.

[0014] US7708804 discloses a method according to the preamble of Claim 1 and US5607557 discloses a device according to the preamble of Claim 9.

[0015] A method of separating NO2 from a fluid comprising CO2 and NO2 is disclosed according to Claim 1.

[0016] A device for separating NO2 from a fluid containing CO2 and NO2 is also disclosed according to Claim 9.

[0017] Either or both of the processes and apparatus may include one or more of the following aspects:

- a fluid containing CO2, NO2 and at least one of oxygen, argon and nitrogen is produced by compressing the waste gas in a compressor, followed by drying and at least partially condensing the compressed waste gas in a heat exchanger.

- the first gaseous stream is at least partially condensed in the heat exchanger; the at least partially condensed stream is separated in a phase separator to produce a third gaseous stream enriched in at least one of oxygen, argon, and nitrogen with respect to the first gaseous stream and a liquid CO2-enriched stream with respect to the first gaseous stream; the liquid CO2-enriched stream is fed to the stripper; a fourth gaseous stream withdrawn from the stripper is fed to the suction inlet of the compressor; and the CO product liquid stream₂ it is discharged from the stripper.

the liquid CO2 product stream is expanded to provide a two-phase CO2 product stream; any liquid component of the two-phase CO2 product stream is vaporized in the heat exchanger to provide a completely gaseous CO2 product stream; and the all-gaseous CO2 product stream is compressed and cooled to provide the CO2 product stream in a supercritical state.

- a sweep gas is fed to the fluid separation membrane, the second gaseous stream further comprising a sweep gas.

- a second gaseous stream is fed to a scrubbing column to dissolve at least a portion of the NO2 present in the second gaseous stream and produce nitric acid.

- fuel is burned with an oxidant in a boiler to produce a waste gas, the waste gas having NO content_X greater than 300 ppm.

the separation layer of the fluid separation membrane comprises a material selected from the group consisting of: cross-linked polysiloxane copolyether, polyurethane-polyether block copolymer, polyurea-polyether block copolymer, polyester-polyether block copolymer, and polyamide-polyether block copolymer.

the heat exchanger at least partially condenses the gaseous stream from the rectification column; the phase separator receives the at least partially condensed stream from the heat exchanger and produces a gaseous stream containing the majority of N₂, ABOUT₂ and / or Ar and a liquid stream containing most of the CO₂; the stripping distillation column receives a liquid stream containing most of the CO2 from the phase separator, the stripper being adapted and configured to separate the contents of a liquid stream containing most of the CO₂ into the gaseous stream and liquid stream of CO product₂.

the compressor and drying unit are adapted and configured to compress and dry the source fluid, the heat exchanger also adapted and configured to at least partially condense the pressurized and dried source fluid prior to feeding to the rectification column.

- the fluid source is a boiler adapted and configured to produce a waste gas, and the waste gas is a fluid containing NO₂ and what₂.

the compressor also receives the gaseous stream from the stripper.

the compressor and cooler compress and completely cool the gaseous CO product stream₂to provide a CO product stream₂ in a supercritical state.

- the membrane also receives a sweep gas on the permeate side of the membrane.

- the scrubbing column receives the gaseous permeate stream and dissolves at least part of the NO₂ present in the gaseous permeate stream to produce nitric acid.

the membrane comprises a separating layer comprising a material selected from the group consisting of: cross-linked polysiloxane copolyether, polyurethane-polyether block copolymer, polyurea-polyether block copolymer, polyester-polyether block copolymer, and polyamide-polyether block copolymer.

Figure 1 is a schematic view of an oxygen combustion plant.

Figure 2 is a schematic view of the compression and purge unit.

Figure 3 shows a low temperature purification unit.

[0018] The invention will now be described in more detail with reference to the figures.

[0019] Figure 1 is a schematic view of an oxygen combustion plant. The air separation unit 2 produces an oxygen stream 10 of typical purity 95-98 mol%. and waste nitrogen stream 13. The oxygen stream 10 is divided into two sub-streams 11 and 12. The main recycle waste gas stream 15 passes through coal mills 3 where the coal 14 is pulverized. Sub-stream 11 is mixed with the recycle stream downstream of the coal mills 3 and the mixture is fed to the burners of the boiler 1. Sub-stream 12 is mixed with the secondary recycle off-gas stream 16, which provides additional load on the burners to keep the furnace temperature at an acceptable level. . Water stream (s) are introduced into the boiler 1 to produce the steam stream (s) 18 which is / are expanded in the steam turbine 8.

[0020] One skilled in the art will recognize that the off-gas to be treated in accordance with the invention may instead be derived from well-known oxy-fuel combustion schemes differing from that illustrated in Figure 1.

[0021] A CO2 rich off-gas stream 19 typically containing more than 70 mol%. on a dry weight basis, it is subjected to several treatments to remove impurities. The unit 4 is a NOx removal system such as a selective catalytic reduction (SCR) unit. Unit 5 is a dedusting system such as an electrostatic precipitator and / or bag filters. Unit 6 is a desulfurization system adapted and configured to remove SO2 and / or SO3. Units 4 and 6 may not be necessary depending on the CO2 product specifications. The off-gas stream 24 is then introduced into the compression and purification unit 7 to produce a high purity CO2 stream 25 suitable for transportation, injection into a pipeline, use in enhanced oil recovery, and / or sequestration in a geological formation. Unit 7 also produces a waste stream 26.

[0022] While the exhaust gas of Figure 1 is derived from oxygen combustion, one skilled in the art will recognize that a NOx reduced CO2 product can also be produced from an exhaust gas derived from air combustion or oxygen-enriched combustion.

Figure 2 is a schematic view of the compression and purification unit that may be used as unit 7 in Figure 1. The off-gas stream 110 (corresponding to stream 24 of Figure 1) enters the low pressure pretreatment unit 101 where it is prepared for compression unit 102. This unit may include, for example, the steps of:

- a wet dedusting step in a scrubber and / or a dry or dynamic process, such as impulse or static inserts, such as pockets and inserts;

- a (further) wet desulfurization step in a water and / or soda ash scrubber or caustic soda injection; and

- a cooling step to minimize the flow due to water condensation and the power of the compression unit, both due to the drop in flow and temperature.

[0024] The waste stream (s) 111 may / may contain condensed water, dust, and dissolved elements such as H2SO4, HNO3, Na2SO4, CaSO4, Na2CO3 and CaCO.

The compression unit 102 compresses the stream 112 from about atmospheric pressure to high pressure, typically between 15 and 60 bar abs, preferably around 30 bar abs. This compression can be carried out in several steps with intermediate cooling. In such a case, some condensate (s) 113 may be formed. Such condensate (s) 113 typically contain (s) HNO3 formed by the reaction of NO2 and water. The heat of compression can be successfully recovered in an intermediate cooling step, for example in preheating the boiler feedwater. The hot stream 114 leaves the compression unit 102 and enters the high pressure pretreatment unit 103.

[0026] The high pressure pretreatment unit 103 comprises at least:

- one or more cooling stages to lower the temperature and reduce the water content; and

- a drying step to remove most of the water, for example by adsorption.

[0027] The high pressure pretreatment unit 103 may also include, but is not limited to:

- high pressure washing column for cooling and / or purification; and

- mercury removal step.

[0028] The waste water from unit 103 comprises gaseous stream 115 (regeneration stream from drying step) and may include liquid stream (s) 116/117 (from cooling step and / or high pressure wash column).

[0029] Stream 114 may contain NO₂. In such a case, it is sometimes advantageous to remove NO2 by adsorption upstream of the device 104. In this case, stream 114 may be treated by adsorption, and the regenerative gas used to regenerate the adsorbent is removed with a NO2-enriched content with respect to stream 114. Gaseous stream 115 may be treated by adsorption. possibly be recycled at least partially upstream of the compression unit 102, upstream of the pretreatment unit 101, or into the boiler 1 of the combustion unit.

[0030] Unit 104 is a low pressure purifier. In this case, low temperature means a minimum temperature in the off-gas cleaning process cycle below 0 ° C, and preferably below -20 ° C as close as possible to the triple point temperature of pure CO2 at -56.6 ° C. In this unit, stream 118 is cooled and partially condensed in one (or more) steps. One (or more) CO2 enriched / enriched liquid phase stream (s) is recovered, depressurized and evaporated to yield a CO2 enriched product 119. This gaseous CO2 product may be used on site. Alternatively, the recovered CO2-enriched liquid phase stream (s) may be maintained in a liquid form and under a pressure and temperature controlled according to known techniques to provide a liquid CO2 product stream suitable for storage, on-site consumption, or transportation. using a battery car. As another alternative, the pressure and temperature of the recovered CO2-enriched liquid stream (s) may be adjusted in accordance with known techniques to provide a supercritical CO2 product stream suitable for injection into a pipeline or sequestered in a geological formation. . One (or several) non-condensable stream (s) 120 under high pressure is relieved and may be expanded (s) in an expander.

[0031] The unit 104 includes a distillation rectification column in which to split the NO2 and CO2-enriched feed stream into a gaseous CO2-enriched stream and a NO2-enriched liquid stream (based on the concentrations of NO2 and CO2 in the feed). The feed fluid may consist of stream 118 or may be derived from stream 118 after further treatment of stream 118.

Unit 104 also includes a fluid separation membrane (operated under pervaporation conditions) that separates the NO2-enriched liquid stream from the rectification column into a NO2-enriched gaseous permeate stream and a non-permeate liquid stream. The liquid non-permeate stream is recycled to the rectification column.

The unit 104 also includes a phase separator that expands the gaseous CO2-enriched stream from the rectification column and separates it into a gaseous stream (for optional deaeration) and a liquid stream to be fed to the stripping distillation column (which also receives a stripping fluid from the rectification column). from the evaporation of at least part of the liquid non-permeate stream). The distillation column removes the non-condensable components (O2, N2 and Ar) from the combined contents of the stripping fluid and the liquid stream (from the phase separator) to the gaseous stream and the CO2 enriched liquid phase stream (s). The gaseous stream from the stripper may combine with the feed fluid fed to the rectification column.

[0034] The CO2-enriched product 119 may be further processed to deliver it in any form (gaseous, liquid, supercritical, solid) and at the desired pressure / temperature. In the case of sequestration, the CO2-enriched product 119 may be further compressed, condensed, and then further pressurized by a pump to deliver it under high pressure (typically 100 to 200 bar abs) for injection into the pipeline leading to the sequestration site.

[0035] Figure 3 shows a low temperature purification unit that can be used as the unit 104 in Figure 2. In such a unit at least one method according to the invention operates.

[0036] Stream 118 containing off-gas at a pressure of about 30 bar and a temperature between 15 ° C and 43 ° C contains mainly carbon dioxide, but also includes minor amounts of NO2, oxygen, argon and nitrogen. The actual amount of NOx will vary with time depending on the amount of NOx already adsorbed in the dryers. Typically the inlet NOx will range between 0 ppm and 500 ppm. The actual amount of NOx will also depend on the type of burner producing the waste gas. Stream 118 may be produced by the unit 103 already under the desired pressure conditions or may be brought to the desired pressure level by an optional compressor 124. The compressed off-gas stream 127 is alternately directed to one of the two dryers 129, 131. While one of the dryers 129 131 serves a dry stream 127, the other dryer is regenerated.

[0037] The dried, compressed off-gas stream 133 is cooled and at least partially condensed in the multi-fluid heat exchanger 135.

[0038] A liquid or two-phase off-gas stream 137 is fed to a rectification column (also known as De-NOx) 139 as recycle and separated into a NO2-enriched liquid stream 141 and a CO2-enriched gaseous stream 143. The pressure in the De NOx column is typically about 25 bar abs, the inlet gas temperature being about -19 ° C.

[0039] The liquid NO2-enriched stream 141 is fed to the feed gas side of the pervaporative separation membranes 147. Membrane 147 includes a separation layer that consists of a material through which NO2 (and SO2, if any) permeates selectively over CO2 so as to provide NO2-enriched permeate and CO2-enriched non-permeate. Optional scavenger gas 145 fed to the penetration side (opposite to the feed gas side) of the membrane 147 will improve the transmission of NO2 from stream 141 through the membrane 147 from the feed gas side to the permeation side by reducing the partial pressure on the permeate side. The combined scavenger 145 and NO2-enriched permeate are withdrawn from the membrane 147 as stream 149.

[0040] The CO2-enriched non-permeate withdrawn from the diaphragm 147 as liquid stream 151 is pressurized using a pump 153. The compressed liquid stream 155 is combined with stream 192 and recycled to the rectification column 139.

[0041] Gaseous stream 143, containing between about 1-5 ppm NO2 and about 98% CO2, is cooled and at least partially condensed in a heat exchanger 135 to provide a cool two-phase stream 161. The two-phase stream 161 is then fed to a phase separator 163. to deliver N-enriched₂, O2 and Ar gaseous stream 165 and CO2 enriched liquid stream 167.

[0042] Stream 165 is heated in a heat exchanger 135, and the thus heated stream 169 is further heated in a heater or heat exchanger 171. The twice-heated stream 171 is regenerated in dryer 129, 131 operating in the regenerative mode, and then heated in heat exchanger 177 to increase the available expansion energy recovered in expander 179. Downstream of expander 179, it is heated in a heat exchanger 135 and the heated, expanded stream 120 is vented.

[0043] The pressure of the CO2-enriched liquid stream 167 drops on the expansion valve and is fed back to the stripper 186. Column 186, at a pressure of about 15 bar and a temperature between -27 ° C and -50 ° C, works to remove the impossible. for condensing the components (N2, O2 and Ar) as a CO2-depleted gaseous stream 187 from overhead of column 186. Part of the cold energy of stream 187 is recovered in the heat exchanger 135, thereby providing a heated stream 189 which merges with the off-gas stream 118 at the suction inlet of the compressor 124.

[0044] A liquid carbon dioxide stream 191 is also withdrawn from the bottom of column 186 and split into stream 192, stream 194 and stream 196. Stream 192 is combined with liquid non-permeate stream 155 to provide stream 157 that is fed to the rectification column. 139. Pressure of stream 194 is dropped across expansion valve 193 to provide a cooler, two-phase (liquid / gaseous CO2) stream 195. The latent heat in stream 195 is recovered in heat exchanger 135 by evaporating the residual liquid phase of two-phase stream 195 to provide gaseous stream 197.

[0045] The CO2 in stream 196 is heated in two portions in the heat exchanger 135 to a different extent. The resulting stream 198 is superheated while stream 200 remains at its dew point and is fed to stripper 186 to provide the necessary heat to the column.

[0046] Stream 197 and stream 198 then combine at the suction inlet of compressor 199, compressed in compressor 199, and cool in heat exchanger 201 to a level above the critical pressure of CO2. The pressure of the cooled compressed stream is then raised above the critical pressure of CO2 to provide a supercritical stream 119 of CO2 enriched product useful for injection into the pipeline.

[0047] One skilled in the art will recognize that the CO2-enriched product 119 may instead be provided in a liquid form for storage, for on-site consumption and / or for shipment by battery car. The liquid CO2 stream 191 also need not be fed to the expansion valve 193 or passed through a heat exchanger 135. In fact, the pressure and / or temperature of the liquid CO 2 stream 191 may be adjusted in accordance with techniques well known in the art to provide any desired pressure and temperature for the CO 2 enriched liquid product 119.

[0048] The membrane 147 includes a permeation-selective release layer that is primarily responsible for separating NO2 (along with SO2, if any) and CO2. The diaphragm 147 may be made entirely of polymeric material of the release layer. The diaphragm 147 may instead be a composite structure where the separation layer is supported by a support layer designed to provide mechanical strength. The support layer material may be any material known to those skilled in the fluid separation membrane art to exhibit relatively high flow and sufficiently desirable mechanical strength. The membrane 147 may have any configuration known to those of skill in the art of fluid separation membranes, including spiral wound sheets and hollow fibers.

[0049] The membrane 147 operates on the principle of solubility selectivity. The solubility is usually correlated with molecular parameters such as the Lennard-Jones affinity constant or critical temperature. As the critical temperatures of NO2 and SO2 are above 157 ° C and the critical temperature of CO2 is only 30.98 ° C, it is considered to be expected that NO2 and SO2 will have high permeability to polymers with flexible backbones and having polar affinity.

[0050] A number of polymeric materials are suitable for use in the membrane partition layer 147, including polysiloxane copolyethers (which are cross-linked), polyurethane-polyether block copolymers, polyurea-polyether block copolymers, polyester-polyether block copolymers, and polyamide-polyether block copolymers.

[0051] In the case of a cross-linked polysiloxane copolyether, it is a polysiloxane copolyether comprising a polymer chain containing repeating units of the molecular moiety of formula (1), the final molecular moiety -OW bonded to a silicon atom at one end of the chain, where O is oxygen and molecular fragment -W bound to the oxygen atom at the other end of the chain:

/ ch₃ ;

--Sj —O— (*!

(1) .

)

[0052] Each W is selected from the group consisting of -Si (CH3) 3, a molecular moiety of formula (2), a molecular moiety of formula (3) and a molecular moiety of formula (4);

- (CH₂)_p-X-OH (2)

- (CH2)_P.-NH- (CH₂) q-NH2 (3)

ABOUT

AND THEIR₂) p —X— OC-CH = CH₂

H).

[0053] Each X contains b repeating units of the molecular fragment of formula (5) and c repeating units of the molecular fragment of formula (6):

- (O-CH2-CH2) - (5)

CH₃ - (O-CH₂-CH) - (6).

J.

[0054] Each R is individually selected from the group consisting of a phenyl group, a C1-C6 alkyl group, a molecular moiety of formula (2), a molecular moiety of formula (3) and a molecular moiety of formula (4);

[0055] In order to ensure the presence of a polyether content in the polysiloxane copolyether, the following two conditions are used. First, if each W is a -Si (CH3) 3 group or a molecular moiety of formula (3), then at least some of the R's are a molecular moiety of formula (2) or a molecular moiety of formula (4). Second, when each R is either a phenyl group or a C1-C6 alkyl group, then each W is either a molecular moiety of formula (2) or a molecular moiety of formula (4)

[0056] The following integers have the following ranges:

p: 1-3;

q: 1-3;

b: 0-400;

c: 0-200.

[0057] The number of repeating units where R is a C1-C6 alkyl group is 1-2000.

[0058] The ratio of the polyether fragments to the polysiloxane fragments may vary. When W is -Si (CH3) 3, the cross-linking sites are in the middle of the chain and the ratio of the number of molecular fragments of formula (5) or (6) to the number of silicon atoms in the chain ranges from about 0.05 to about 6 , 0. When each R is either a phenyl or a C1-C6 alkyl group, the crosslinking sites are at each end of the chain and the ratio of the number of molecular moieties of formula (5) or (6) to the number of silicon atoms in the chain ranges from about 0 .05 to approx

0.33- In this case, a higher content of siloxane-based repeating units is desirable for greater strength.

[0059] A potential cross-linking site may exist wherever W or R is a molecular moiety of formula (2), (3) or (4). The type of linkage formed at the cross-linking site will depend on the particular W or R and the type of cross-linking agent or cross-linking promoter. For the molecular moieties W and R of formula (2), a methane bond may be formed using a crosslinker consisting of a monomeric diisocyanate, monomeric triisocyanate or a polymeric isocyanate. For the W and R molecular fragments of formula (3), a urea bond can be formed using a crosslinking agent consisting of a monomeric diisocyanate, monomeric triisocyanate or a polymeric isocyanate. For the molecular moieties W and R of formula (3), an amide bond may instead be formed using an aromatic diacyl chloride substituted crosslinker or an aromatic triacyl chloride substituted crosslinker. For the W and R molecular fragments of formula (4), the copolymer may be cross-linked using a free radical cross-linking promoter such as an azo or peroxide free radical initiator.

[0060] Non-limiting examples of suitable monomeric diisocyanate, monomeric triisocyanate, or polymeric isocyanate crosslinkers are toluene diisocyanate (TDI) commercially available from a wide variety of sources or cyanate-functionalized siloxanes commercially available from Siltech. Non-limiting examples of suitable aromatic diacyl chloride substituted crosslinkers and aromatic triacyl chloride substituted crosslinkers include 1,3-benzenedicarbonyl dichloride, 1,4-benzenedicarbonyl dichloride, and 1,3,5-benzenedicarbonyl trichloride.

[0061] The cross-linked polysiloxane copolyether may optionally be cross-linked together with one or more silicone elastomers. The silicone elastomer may be derived from a first silicone polymer having a first reactive functional group (such as a vinylsiloxane unit) and a crosslinker having a second reactive functional group (such as a hydrogen siloxane unit). Suitable silicone elastomers may be commercially available from Momentive under the tradename RTV615 and from Dow Corning under the tradename Sylgard 184, 182 or 186.

[0062] Particularly suitable types of polysiloxane copolyethers may be commercially available from Siltech under the trade names D-208, Di-2510, Di-5018F, Di-10 and J1015-O.

[0063] Polyurethane-polyether block copolymers are prepared by reacting at least one polyether glycol with an aromatic or aliphatic diisocyanate, followed by reaction with at least one aliphatic diol (to form a polyurethane polyether) or with at least one aliphatic diamine (to form a polyurea polyether) in the presence of a catalyst such as organotin compounds such as dibutyltin dilaurate, but other catalysts known to the person skilled in the art can be used. The resulting polymers contain soft fragments of formula (I._s) containing a polyether and rigid fragments of formula (Ih) containing polyurethane or polyurea.

The obtained polyurethane-polyether or polyurea-polyether block copolymers are represented by repeating units of formulas (I_s) and (Ih):

<img file="PL3145606T3_D0001.tif" />

(Is)

<img file="PL3145606T3_D0002.tif" />

Ri in the formulas (i_s) and (Ih) is an aliphatic or aromatic radical of at least about 2-18 carbon atoms. (PE) is a number average molecular weight polyether moiety, M._n (which is essentially equivalent to M._n Repeating Formula (Is)) ranging from about 600 to 8,000, and preferably about 1,000 to 4,000._and w (Ih) is a linear or branched aliphatic radical of at least about 2-18 carbon atoms; and X is oxygen or -NH-. When X is oxygen, the block copolymer is polyurethane-polyether, and when X is -NH-, the block copolymer is polyurea-polyether. In a block copolymer, the number of carbon atoms in the repeating units can vary, and variations and combinations of the number of carbon atoms can occur. The number-average molecular weight of the repeating formula (Ih) is preferably in the range of about 200 to 3,000, and more preferably about 200-1,000. More specifically, in one copolymer, Ri is a linear - (CH2) - group or a composition moiety selected from the group consisting primarily of formula (S), formula (T), formula (U) or (V) below, and combinations or mixtures thereof .

<img file="PL3145606T3_D0003.tif" />

(S) (T)

<img file="PL3145606T3_D0004.tif" />

(U) (V)

These structures correspond to 1,6-hexane diisocyanate, 2,6 tolylene diisocyanate, 2,4-toluene diisocyanate, 1,3-xylylene diisocyanate and 4,4'-methylenebis (phenylisocyanate), respectively. The polyether moiety (PE) is preferably derived from a polyether glycol having a number average molecular weight of about 600-8,000, and more preferably about 1,000-4,000, and preferably having an oxygen / carbon ratio of about 0.2-0.5. Preferred polyether glycols are hydroxyl terminated polyethylene glycol, hydroxyl terminated 1,2-polypropylene glycol, and hydroxyl terminated 1,4-polybutylene glycol, although other glycols known or used by those skilled in the art may be used.

[0065] The rigid polyurethane-polyether or polyurea-polyether block copolymer fragment is derived from the reaction of residual aliphatic or aromatic diisocyanate end groups or monomer or with at least one aliphatic diol or at least one aliphatic diamine. Preferred diols or diamines contain at least about 2-18 carbon atoms and may be linear or branched. Most preferred are diols or diamines containing at least about 2-6 carbon atoms. Typical diols and diamines are: ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,6hexanediol, 1,2-diaminoethane, 1,4-diaminobutane, 1,5-diaminopentane, 1 , 5-diaminohexane, 1,6-diaminohexane, and dl-serine (3-amino-2-hydroxypropionic acid), although other diols and diamines known or used by one skilled in the art may be used. Typically the polyurethane-polyether or polyurea-polyether block copolymers have a number average molecular weight ranging from about 23,000 to 400,000, and preferably from about 50,000 to 280,000. As shown by the various combinations of components, a wide range and variety of types of polyurethane-polyether and polyurea-polyether block copolymers are contemplated and disclosed herein. Typically, the soft portion comprises about 50-90 percent by weight of the block copolymer, and more typically about 60-85 percent.

[0066] Polyester-polyether block copolymers are prepared by reacting at least one hydroxyl-terminated polyether glycol, an excess of at least one aliphatic diol, and at least one aromatic dicarboxylic ester or aliphatic diacid in the presence of a catalyst. The resulting polymers contain soft fragments of formula (II_S.) containing a polyether and stiff pieces of formula (IIh) containing polyester:

<img file="PL3145606T3_D0005.tif" />

<img file="PL3145606T3_D0006.tif" />

(fox)

R_and in (IL) and (Uh) is an aliphatic or aromatic radical of at least 2-18 carbon atoms. (PE) in (II_S.) represents a number average molecular weight polyether moiety M_n (which is essentially equivalent to M._n repeating pattern (II_S.)) ranging from about 600 to 8,000, and preferably about 1,000 to 4,000. Ra (IIh) is at least one linear or branched aliphatic radical having at least about 2-18 carbon atoms. In a polyester-polyether block copolymer, the number of carbon atoms in the repeating units can vary, and variations and combinations of the number of carbon atoms can exist. The average molecular weight of the repeating formula (IIh) is preferably in the range of about 200 to 3,000, and more preferably about 200-1,000. In a preferred embodiment of the invention, R._and represents a composition moiety selected from or consisting of the following formulas (S), (T), (U), (V), (W), (X) or (Y), or a combination or mixture thereof:

<img file="PL3145606T3_D0007.tif" />

[0067] Further, when formula (Y) is present or included, -Z- in formula (Y) is a moiety selected from or consisting of the following formulas (A), (B), (C) or

<img file="PL3145606T3_D0008.tif" />

(Υ) (D) or a mixture or combination thereof:

-CH₂-(AND)

-O- (B)

O (C) (D)

[0068] The polyether (PE) moiety of the polyester-polyether block copolymer is preferably derived from a polyether glycol having a number average molecular weight of about 600-8,000, and more preferably about 1,000-4,000, and preferably having an oxygen / carbon ratio of about 0.2-0.5. Preferred polyether glycols are hydroxyl terminated polyethylene glycol, hydroxyl terminated 1,2-polypropylene glycol, and hydroxyl terminated 1,4-polybutylene glycol, although other glycols known or used by one skilled in the art may be used. The rigid block copolymer fragment is derived from the condensation polymerization of at least one aromatic or aliphatic diacid ester with at least one aliphatic diol. The moiety R d in formula (Ih) is derived from an aliphatic diol. Preferred diols contain at least about 2-18 carbon atoms and may be linear and / or branched. Diols containing between about 2-6 carbon atoms are most preferred. Typical diols are ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, and 1,6-hexanediol, although other diols known or used by one skilled in the art may be used. Typically the polymers of the present invention have a number average molecular weight ranging from about 23,000 to 400,000, and preferably about 50,000 to 280,000. As shown by the various combinations of components, various types of polyester-polyether block copolymers are contemplated and disclosed herein.

[0069] Typically, the soft piece of the polyester-polyether block copolymer comprises about 50-90 percent by weight of the copolymer by weight, and more typically about 60-85 percent.

[0070] The polyamide-polyether block copolymers contain the repeating units of the moiety of formula III:

<img file="PL3145606T3_D0009.tif" />

(I) where PA is a saturated aliphatic polyamide moiety and PE is a polyether moiety. Typically, a saturated aliphatic polyamide fragment is:

- Nylon 6 (PA6), which is poly [imino (1-oxohexamethylene)], or

- Nylon 12 (PA 12) which is poly [imino (1-oxododecamethylene)].

[0071] Typically, the polyether moiety is:

- PEO, which is poly (ethylene oxide), or

- PTMEO, which is poly (tetramethylene oxide).

[0072] One particularly suitable group of polyamide-polyether block copolymers is commercially available from Arkema under the trade name ΡΕΒΑΧ. They are obtained by polycondensing a carboxylic acid polyamide (PA6, PA11, PA12) with an alcohol-terminated polyether, such as poly (tetramethylene glycol) (PTMG) or polyethylene glycol (PEG).

[0073] The singular forms include the plural references unless the context clearly dictates otherwise.

[0074] "Including" in the claim is an open transitional term, meaning that elements of the claim later identified are non-exclusive listing, ie, anything else may additionally be included and fall within the scope of "comprising". "Comprising" is defined herein as necessarily including the more limited transitional terms "consisting essentially of" and "consisting of"; "Comprising" can therefore be replaced by "consisting essentially of" or "consisting of" and remains within the clearly defined scope of the term "comprising".

[0075] "Providing" in a claim is defined as the provision, provision, provision or preparation of something. The stage can be carried out by any person in the absence of an explicit linguistic statement as stipulated otherwise.

[0076] Optional or alternatively means that the later described event or circumstances may or may not occur. The description includes the cases where the event or circumstance occurs and the cases where it does not.

[0077] Ranges may be expressed herein from about one particular value, and / or up to about another specific value. When a range is expressed in such a manner, it is to be understood that in another embodiment it ranges from one specific value and / or to another specific value, including all combinations therein.