CN112041614A - Single-layer expansion water tank diaphragm - Google Patents
Single-layer expansion water tank diaphragm Download PDFInfo
- Publication number
- CN112041614A CN112041614A CN201980024976.3A CN201980024976A CN112041614A CN 112041614 A CN112041614 A CN 112041614A CN 201980024976 A CN201980024976 A CN 201980024976A CN 112041614 A CN112041614 A CN 112041614A
- Authority
- CN
- China
- Prior art keywords
- membrane
- copolymer
- styrene
- thermoplastic elastomer
- expansion tank
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000002356 single layer Substances 0.000 title claims abstract description 32
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title description 24
- 150000001336 alkenes Chemical class 0.000 claims abstract description 36
- 229920002725 thermoplastic elastomer Polymers 0.000 claims abstract description 33
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 claims abstract description 32
- 229920000098 polyolefin Polymers 0.000 claims abstract description 32
- 239000000203 mixture Substances 0.000 claims abstract description 21
- 239000012528 membrane Substances 0.000 claims description 96
- 229920006132 styrene block copolymer Polymers 0.000 claims description 18
- 229920001400 block copolymer Polymers 0.000 claims description 17
- 229920000346 polystyrene-polyisoprene block-polystyrene Polymers 0.000 claims description 14
- 238000004519 manufacturing process Methods 0.000 claims description 13
- RRHGJUQNOFWUDK-UHFFFAOYSA-N Isoprene Chemical compound CC(=C)C=C RRHGJUQNOFWUDK-UHFFFAOYSA-N 0.000 claims description 12
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 claims description 12
- 239000004715 ethylene vinyl alcohol Substances 0.000 claims description 12
- 229920002397 thermoplastic olefin Polymers 0.000 claims description 12
- 229920000219 Ethylene vinyl alcohol Polymers 0.000 claims description 11
- 238000010438 heat treatment Methods 0.000 claims description 7
- 238000001746 injection moulding Methods 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 6
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 claims description 6
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 claims description 6
- 239000004793 Polystyrene Substances 0.000 claims description 5
- 239000000654 additive Substances 0.000 claims description 5
- 239000000155 melt Substances 0.000 claims description 5
- 229920002223 polystyrene Polymers 0.000 claims description 5
- 229920000359 diblock copolymer Polymers 0.000 claims description 4
- 230000002093 peripheral effect Effects 0.000 claims description 4
- 238000001816 cooling Methods 0.000 claims description 3
- 230000000996 additive effect Effects 0.000 claims description 2
- 229920005629 polypropylene homopolymer Polymers 0.000 claims description 2
- UFRKOOWSQGXVKV-UHFFFAOYSA-N ethene;ethenol Chemical compound C=C.OC=C UFRKOOWSQGXVKV-UHFFFAOYSA-N 0.000 claims 1
- 239000004636 vulcanized rubber Substances 0.000 abstract description 5
- 229920002803 thermoplastic polyurethane Polymers 0.000 description 15
- 239000004433 Thermoplastic polyurethane Substances 0.000 description 13
- 229920000642 polymer Polymers 0.000 description 13
- 229920001169 thermoplastic Polymers 0.000 description 12
- 239000004416 thermosoftening plastic Substances 0.000 description 11
- 239000007789 gas Substances 0.000 description 10
- RZXDTJIXPSCHCI-UHFFFAOYSA-N hexa-1,5-diene-2,5-diol Chemical compound OC(=C)CCC(O)=C RZXDTJIXPSCHCI-UHFFFAOYSA-N 0.000 description 10
- 229920001198 elastomeric copolymer Polymers 0.000 description 9
- 238000012360 testing method Methods 0.000 description 9
- 229920001971 elastomer Polymers 0.000 description 8
- 239000000463 material Substances 0.000 description 8
- -1 poly (ether esters Chemical class 0.000 description 8
- 239000005060 rubber Substances 0.000 description 8
- 230000004888 barrier function Effects 0.000 description 7
- 239000010410 layer Substances 0.000 description 7
- 239000004743 Polypropylene Substances 0.000 description 6
- 239000007788 liquid Substances 0.000 description 6
- 230000035699 permeability Effects 0.000 description 6
- 239000003651 drinking water Substances 0.000 description 5
- 235000020188 drinking water Nutrition 0.000 description 5
- 239000003921 oil Substances 0.000 description 5
- 229920001155 polypropylene Polymers 0.000 description 5
- 229920000909 polytetrahydrofuran Polymers 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 239000005977 Ethylene Substances 0.000 description 4
- 239000002174 Styrene-butadiene Substances 0.000 description 4
- 229920003048 styrene butadiene rubber Polymers 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 239000004721 Polyphenylene oxide Substances 0.000 description 3
- 238000010382 chemical cross-linking Methods 0.000 description 3
- 229920001577 copolymer Polymers 0.000 description 3
- 125000004122 cyclic group Chemical group 0.000 description 3
- 229920000570 polyether Polymers 0.000 description 3
- 229920000428 triblock copolymer Polymers 0.000 description 3
- UPMLOUAZCHDJJD-UHFFFAOYSA-N 4,4'-Diphenylmethane Diisocyanate Chemical compound C1=CC(N=C=O)=CC=C1CC1=CC=C(N=C=O)C=C1 UPMLOUAZCHDJJD-UHFFFAOYSA-N 0.000 description 2
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
- 229920005557 bromobutyl Polymers 0.000 description 2
- 238000004132 cross linking Methods 0.000 description 2
- 230000001351 cycling effect Effects 0.000 description 2
- 150000001993 dienes Chemical class 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 125000005442 diisocyanate group Chemical group 0.000 description 2
- 150000002009 diols Chemical class 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 229920001707 polybutylene terephthalate Polymers 0.000 description 2
- 229920000728 polyester Polymers 0.000 description 2
- 229920002959 polymer blend Polymers 0.000 description 2
- 239000012815 thermoplastic material Substances 0.000 description 2
- 229920006345 thermoplastic polyamide Polymers 0.000 description 2
- RLRINNKRRPQIGW-UHFFFAOYSA-N 1-ethenyl-2-[4-(2-ethenylphenyl)butyl]benzene Chemical compound C=CC1=CC=CC=C1CCCCC1=CC=CC=C1C=C RLRINNKRRPQIGW-UHFFFAOYSA-N 0.000 description 1
- VSKJLJHPAFKHBX-UHFFFAOYSA-N 2-methylbuta-1,3-diene;styrene Chemical compound CC(=C)C=C.C=CC1=CC=CC=C1.C=CC1=CC=CC=C1 VSKJLJHPAFKHBX-UHFFFAOYSA-N 0.000 description 1
- 241000894006 Bacteria Species 0.000 description 1
- 239000004970 Chain extender Substances 0.000 description 1
- 229920006347 Elastollan Polymers 0.000 description 1
- 229920002633 Kraton (polymer) Polymers 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 239000005062 Polybutadiene Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 150000001408 amides Chemical class 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- MTAZNLWOLGHBHU-UHFFFAOYSA-N butadiene-styrene rubber Chemical compound C=CC=C.C=CC1=CC=CC=C1 MTAZNLWOLGHBHU-UHFFFAOYSA-N 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 125000004185 ester group Chemical group 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- RTZKZFJDLAIYFH-UHFFFAOYSA-N ether Substances CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 1
- 239000005038 ethylene vinyl acetate Substances 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000010102 injection blow moulding Methods 0.000 description 1
- FPYJFEHAWHCUMM-UHFFFAOYSA-N maleic anhydride Chemical compound O=C1OC(=O)C=C1 FPYJFEHAWHCUMM-UHFFFAOYSA-N 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229920006030 multiblock copolymer Polymers 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000010399 physical interaction Effects 0.000 description 1
- 229920002857 polybutadiene Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001195 polyisoprene Polymers 0.000 description 1
- 229920005862 polyol Polymers 0.000 description 1
- 150000003077 polyols Chemical class 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 229920001384 propylene homopolymer Polymers 0.000 description 1
- 229920003031 santoprene Polymers 0.000 description 1
- 239000011115 styrene butadiene Substances 0.000 description 1
- 229920001935 styrene-ethylene-butadiene-styrene Polymers 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 229920006344 thermoplastic copolyester Polymers 0.000 description 1
- 229920006342 thermoplastic vulcanizate Polymers 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
- 150000003673 urethanes Chemical class 0.000 description 1
- 238000004073 vulcanization Methods 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
- F24D3/00—Hot-water central heating systems
- F24D3/10—Feed-line arrangements, e.g. providing for heat-accumulator tanks, expansion tanks ; Hydraulic components of a central heating system
- F24D3/1008—Feed-line arrangements, e.g. providing for heat-accumulator tanks, expansion tanks ; Hydraulic components of a central heating system expansion tanks
- F24D3/1016—Tanks having a bladder
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J3/00—Diaphragms; Bellows; Bellows pistons
- F16J3/02—Diaphragms
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2201/00—Accumulators
- F15B2201/30—Accumulator separating means
- F15B2201/315—Accumulator separating means having flexible separating means
- F15B2201/3151—Accumulator separating means having flexible separating means the flexible separating means being diaphragms or membranes
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2201/00—Accumulators
- F15B2201/60—Assembling or methods for making accumulators
- F15B2201/61—Assembling or methods for making separating means therefor
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems
- F16L55/04—Devices damping pulsations or vibrations in fluids
- F16L55/045—Devices damping pulsations or vibrations in fluids specially adapted to prevent or minimise the effects of water hammer
- F16L55/05—Buffers therefor
- F16L55/052—Pneumatic reservoirs
- F16L55/053—Pneumatic reservoirs the gas in the reservoir being separated from the fluid in the pipe
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Laminated Bodies (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
Abstract
The invention relates to a single-layer diaphragm for an expansion tank. The single layer separator includes a mixture of a polyolefin and a non-olefin thermoplastic elastomer copolymer or a partially olefin thermoplastic elastomer copolymer. The performance of the diaphragm is at least equivalent to that of a conventional single-layer expansion tank diaphragm made of vulcanized rubber. The single layer separator is recyclable and easy to produce.
Description
Technical Field
The present invention relates to a monolayer membrane for an expansion tank, the use of a styrene block copolymer for the manufacture of a monolayer membrane for an expansion tank, a method for the manufacture of a monolayer membrane and an expansion tank comprising said monolayer membrane.
Background
The expansion tank or expansion vessel protects the closed (not open to atmospheric pressure) liquid system from building up excessive pressure in the system. The tank absorbs the extra liquid pressure caused by thermal expansion. The expansion tank is typically used in a domestic central heating system, but it may also be used in other applications, for example, in a vehicle suspension system.
The working principle of expansion tanks is based on the principle that gases are compressible (as opposed to liquids). The expansion tank consists of two compartments separated by a flexible membrane. One side of the expansion tank is connected to the pipes of the heating system, so that it contains a liquid (usually water). The other side contains pressurized air and typically includes a valve (e.g., a schrader valve for checking pressure and adding air). When the heating system is empty or at the low end of the normal operating pressure range, the diaphragm is pushed towards the liquid inlet. As the liquid volume and pressure increase, for example due to an increase in temperature, the diaphragm moves and thus compresses the air on the other side. When the expansion tank is used in a domestic drinking water system, the membrane and the tank must comply with drinking water regulations.
It is clear that expansion tank membranes should be able to withstand a large number of pressure cycles, wherein the membranes will expand and contract due to pressure changes within the system. After a certain amount of cycles, fatigue can damage the membrane, thereby increasing the water and gas permeability of the membrane.
NEN 13831:2007 establishes the number of cycles that the membrane should be able to withstand without significantly degrading the barrier performance. In this test, an expansion tank with a diaphragm is subjected to continuous cyclic stress (optionally at elevated temperature). The pressurized water is pumped into the water tank until it fills up to 50% of the capacity of the chamber. The diaphragm expands and then releases the pressure again. After the cycling test, once the water tank was cooled (if the test was performed at high temperature (e.g., 75 ℃), the vessel gas side was filled with air to 1.5 bar. The pressure drop in the next hour must not exceed 0.15 bar.
The expansion tank membrane is typically composed of a vulcanized rubber, such as styrene-butadiene (SBR) rubber or brominated butyl rubber (BiiR). However, the manufacture of such membranes can be very cumbersome due to the need for vulcanization, and the resulting membranes are not always suitable for use with drinking water due to the presence of vulcanizing agents and accelerators. Other materials are preferred for use with drinking water. In addition, vulcanized rubber tends to pass small amounts of oxygen and water with time. This can lead to air bubbles in the system and to water in the air compartment of the expansion tank. This causes the expansion tank to gradually decrease in function until the air compartment contains too little air and the pressure drops below the critical value of 0.2 bar. At this point, the expansion tank is no longer functional. Under standard conditions, the maximum service life of vulcanized rubber-based expansion tank membranes is about 15 years. Due to the cross-linking of the rubber, the conventional expansion tank diaphragm is not easy to recycle. For example, it cannot be melted and reshaped.
The membrane with improved gas barrier properties may be made of a thermoplastic material, such as Thermoplastic Polyurethane (TPU), for example, as disclosed in WO 2013/170323. Compared to alternative thermoplastic materials, TPU is relatively inexpensive, easy to process, resilient and not sensitive to bacteria. However, TPU membranes still have relative permeability to water.
US 2010/006532 in a different field discloses a retort (retort) liner for bottles comprising a styrenic block copolymer and one or more polyolefin polymers.
US 2008/017653 discloses a thermoplastic diaphragm assembly for a pressure vessel. The diaphragm is formed from a thermoplastic elastomer material selected from the group consisting of 1. ethylene-vinyl acetate (EVA), 2. rubber, 3. rubber blend, and 4. polypropylene-rubber blend. Expansion tank membranes comprising multiple layers are also known, for example, US 2010/209672. By using multiple layers, the properties that the membrane lacks in one layer (e.g., water impermeability) can be imparted by adding an additional barrier layer on top of another layer, such that the overall membrane has the desired water impermeability, gas impermeability, and durability. However, the production of expansion tank membranes comprising multiple layers is complicated. For example, it may be desirable to produce two or more separate membranes and then stack the membranes on top of each other. The present invention aims to overcome the above-mentioned disadvantages of expansion tank membranes, or at least to provide a useful alternative. It is therefore an object of the present invention to provide an expansion tank diaphragm having sufficient water resistance. It is another object of the present invention to provide an expansion tank diaphragm with adequate gas barrier properties. It is another object of the present invention to provide an expansion tank diaphragm that is easy to manufacture. It is another object of the present invention to provide an expansion tank diaphragm with sufficient mechanical properties. Another object of the present invention is to provide a membrane for an expansion tank that can be recycled. An expansion tank is also provided.
Disclosure of Invention
To achieve at least one of the objects, in a first aspect of the invention there is provided a single layer membrane for an expansion tank comprising a mixture of a polyolefin and a non-olefin thermoplastic elastomer copolymer or a partially olefin thermoplastic elastomer copolymer.
A membrane for the expansion tank may separate the two compartments of the expansion tank. This means that such a membrane needs to be configured to be clamped at the peripheral edge between the first housing part and the second housing part of the expansion tank. For example, the septum may have a beaded circumferential edge.
The expansion tank may be cylindrical (fig. 1) or rectangular (fig. 2) depending on the application. Since the membrane consists of only a single layer, it is easy to produce in a single step by e.g. injection moulding or blow moulding. Since there is no need to stack different membranes on top of each other (e.g. for a multilayer membrane), the production process is relatively fast and easy. Furthermore, since the membrane comprises a thermoplastic elastomer, an expansion tank membrane having desired properties (flexibility, low gas permeability, low water permeability) can be obtained without any chemical crosslinking.
The thermoplastic elastomeric copolymers are crosslinked by physical interaction rather than chemical crosslinking. The polymer chains of the thermoplastic elastomeric copolymers comprise blocks having at least two different incompatible repeating units (so-called soft and hard segments), wherein at least two blocks are present in order to form a crosslinked network. The hard segment phase separates from the soft segment, thereby forming physical crosslinks (as opposed to chemical crosslinks as in the case of, for example, vulcanized rubber) in the matrix of the soft segment polymer, provided that the soft segment polymer is the primary segment. The general classes of thermoplastic elastomeric copolymers are: styrene block copolymers, thermoplastic polyurethanes, thermoplastic copolyesters, and thermoplastic polyamides. These classes are all non-olefins or partial olefins, where non-olefins means that these polymers do not include any olefin repeating units. By partially olefinic is meant that although the polymer may include olefinic repeat units, it also includes non-olefinic repeat units. Thus, the non-olefin thermoplastic elastomeric copolymer or partially olefin thermoplastic elastomeric copolymer comprises non-olefin repeating units. All of the above categories of thermoplastic elastomeric copolymers include non-olefinic repeat units.
The styrene block copolymer is a block copolymer of styrene and a diene (e.g., polyisoprene and/or polybutadiene). The diene may be hydrogenated. The block copolymer is a multi-block copolymer, for example, a triblock copolymer. Examples of styrene block copolymers include poly (styrene-co-ethylene/propylene-styrene) (SEPS), poly (styrene-isoprene-styrene) (SIS), poly (styrene-co-ethylene/butylene-styrene) (SEBS), and poly (styrene-butylene-styrene) (SBS). The polymer may be linear or branched. Further, it may be a mixture of linear block copolymers and branched block copolymers, and/or a mixture including diblock copolymers having a single soft segment and a single hard segment. Such styrene block copolymers are manufactured, for example, by Kraton, Kuraray, TSRC and LCY.
Thermoplastic Polyurethanes (TPU) are block copolymers consisting of alternating sequences of hard and soft segments or of domains formed by the reaction of: (1) reaction of diisocyanates with short chain diols (chain extenders) and (2) reaction of diisocyanates with long chain diols. By varying the proportions, structures and/or molecular weights of the reaction compounds, it is possible to produce TPUs of various structures. This enables the structure to be fine tuned to the desired final properties of the material. For example, the greater the ratio of hard segments to soft segments, the greater the rigidity of the Thermoplastic Polyurethane (TPU). Examples of commercially available TPUs are Desmopan or Elastollan. Preferably, the TPU includes a polytetramethylene ether glycol (PTMEG) polyol.
Thermoplastic copolymers are multiblock copolymers of polyester segments and polyether segments of different chemical nature linked by ester linkages. Typical examples of poly (ether esters) include poly (butylene terephthalate) (PBT) having a soft long poly (tetrahydrofuran) segment connecting hard and short segments by ester groups.
Finally, the thermoplastic polyamide is a block copolymer containing hard segments and soft segments, said block copolymer comprising amide linkages. For example, it is based on nylon and polyether or polyester.
Thermoplastic elastomer copolymers are contemplated with other classes of thermoplastic elastomers (e.g., thermoplastic vulcanizates (e.g., Elastron, Forprene, Santoprene, Trefsin, etc.) and thermoplastic polyolefin elastomers), respectively). In fact, these thermoplastic elastomers are themselves mixtures of various components. For example, thermoplastic polyolefin elastomers are a mixture of thermoplastic polymers (e.g., polypropylene or polyethylene) and pre-crosslinked rubber particles.
Unlike conventional vulcanized and/or crosslinked membranes, the mechanical properties of which require chemical crosslinking, the membranes according to the invention can be melted and reshaped. Furthermore, since no crosslinking chemicals are required, less toxicity of the chemicals is required during the production process.
In WO 2013/151441 a single layer expansion tank membrane made of a thermoplastic elastomer copolymer, which is a Thermoplastic Polyurethane (TPU), is proposed. However, while such membranes may have the desired flexibility and durability, they are relatively water permeable.
Polyolefins are known to have water blocking properties. This is why a polyolefin layer providing water-blocking properties is generally present in a multi-layer expansion tank membrane.
Surprisingly, when it is desired to take advantage of the water-blocking properties of polyolefins, the use of multilayer expansion tank membranes is not required. By mixing the thermoplastic elastomer copolymer and the polyolefin, a single layer membrane for an expansion tank having reduced water vapor permeability can be obtained, as compared with a single layer expansion tank membrane comprising only the thermoplastic elastomer copolymer. Although the durability is reduced compared to prior art single layer expansion tank membranes, it still meets the requirements of expansion tank membranes.
The polyolefin may be essentially composed of olefin repeating units (i.e., C)2-CxOlefin repeating units, preferably C2-C4Olefin repeating units, more preferably propylene and/or ethylene repeating units). In this respect, substantially means that the combined olefin repeat unit content of the (co) polymer is greater than 90 wt%, preferably greater than 95 wt%, even more preferably greater than 99 wt%, with the remainder being derived from copolymerizable non-olefin monomers. For example, to increase the compatibility of the polymer with the thermoplastic elastomer, the polymer may include a small amount of non-olefinic moieties. For example, the polyolefin may be grafted with other monomer units, such as maleic anhydride. Preferably, the amount of non-olefinic repeat units in the polyolefin is no greater than 10 wt%, more preferably no greater than 5 wt%, and most preferably no greater than 1 wt%. Preferably, the polyolefin does not comprise any non-olefinic repeat units.
In a second aspect, the present invention provides a method of manufacturing a single-layer membrane for an expansion tank, the method comprising
a) Heating and mixing a polyolefin and a non-olefin thermoplastic elastomer copolymer or a partially olefin thermoplastic elastomer copolymer,
b) injection molding the mixture of a) into a membrane mold to form a single-layer membrane,
c) optionally cooling the membrane in a membrane mould,
d) removing the membrane from the mold.
Heating and mixing may be carried out in an extruder. Preferably, in step a), the polyolefin and the thermoplastic elastomeric copolymer are heated to a temperature between 200 ℃ and 220 ℃. The injection molding in step b) is preferably carried out at a pressure of between 130 bar and 150 bar, with an injection molding time of between 1 second and 4 seconds.
In a third aspect, the present invention provides the use of a styrenic block copolymer for the manufacture of a monolayer membrane for an expansion tank.
Finally, an expansion tank comprising a single-layer membrane according to the invention is provided.
Description of the embodiments
Preferably, the diaphragm is a separator. Such a diaphragm has a substantially spherical circumference that can be clamped between the two halves of the expansion tank. The remainder of the barrier film may have a substantially hat-shaped form including a substantially flat outer region and an inner region that is at least partially curved and defines a volume. The thickness of the membrane is preferably at least 0.8 mm. It should be noted that barrier membranes are distinct from air bag membranes or spherical membranes.
Preferably, the polyolefin polymer or copolymer comprises propylene repeating units having a propylene content of at least 80 wt%. More preferably, the polyolefin is a copolymer of ethylene and propylene. Alternatively, the polyolefin is a propylene homopolymer due to the superior water blocking properties of polypropylene compared to other polyolefins. Even more preferably, the polyolefin is a polypropylene having a melt flow index according to ASTM D1238(200 ℃/2.16kg) of between 5g/10min and 100g/10min, most preferably between 10g/10min and 100g/10 min.
Preferably, the non-olefin thermoplastic elastomeric copolymer or partially olefin thermoplastic elastomeric copolymer is a styrene block copolymer. More preferably, the styrenic block copolymer is a block copolymer of styrene and isoprene, most preferably a poly (styrene-isoprene-styrene) triblock copolymer or a mixture of said triblock copolymer and diblock copolymer. Desirably, the block copolymer has a melt flow index (ASTM D1238, 200 ℃/5kg) of between 2g/min and 24 g/min. Most preferably, the melt flow index (ASTM D1238, 200 ℃/5kg) of the block copolymer is between 8g/min and 19 g/min. In addition to favoring the water permeation rate, the mechanical properties of expansion tank membranes comprising a mixture of styrene block copolymers (particularly poly (styrene-isoprene-styrene) triblock copolymers) and polyolefins (particularly polypropylene) are comparable to those of conventional vulcanized expansion tank membranes, while exhibiting good gas and water permeation rates over a longer period of time.
Preferably, the polystyrene content of the poly (styrene-isoprene-styrene) triblock copolymer is between 10 and 25 wt.%, preferably between 12 and 21 wt.%, most preferably between 14 and 17 wt.%. Without being bound by theory, we speculate that the triblock copolymer is more flexible due to the smaller amount of polystyrene blocks compared to the intermediate isoprene blocks, which gives the expanded tank membrane sufficient mechanical properties.
The composition for the separator may include up to 50% by weight of other components, i.e., additives. Such additives may include fillers, colorants, and other polymers, among others.
Preferably, the single layer expansion tank membrane does not comprise ethylene vinyl alcohol (EVOH) or EVOH copolymers. EVOH has excellent gas barrier properties. However, they have poor mechanical properties and are not resistant to water and/or water vapor. Therefore, EVOH is commonly used as the middle layer of a multilayer expansion tank membrane, with the outer layers providing water-blocking properties. Furthermore, it is a relatively expensive polymer. EVOH or EVOH copolymers may be blended with the polymer mixture used to produce single layer expansion tank membranes. The addition of EVOH or EVOH copolymers in this manner may be beneficial for the performance of the expansion tank membrane. However, it is a relatively expensive polymer. Therefore, the use of EVOH or EVOH copolymer is not preferable.
Preferably, the single layer expansion tank membrane does not include oil. Oils are often added to polymer blends (e.g., as processing oils) to improve processability. However, such oil may leak out of the diaphragm. This is undesirable, especially in the case of drinking water applications.
Preferably, the separator comprises between 10 and 60 wt.%, preferably between 20 and 60 wt.%, more preferably between 25 and 50 wt.% of a non-olefinic thermoplastic elastomer copolymer or a partially olefinic thermoplastic elastomer copolymer.
Preferably, the separator consists of 10-60 wt% of a non-olefin thermoplastic elastomer copolymer or a partially olefin thermoplastic elastomer copolymer, 40-90 wt% of a polyolefin and 0-20 wt% of additives, the total amount adding up to 100 wt%.
The terms "a"/"an" as used herein are defined as one or more than one. The terms including and/or having, as used herein, are defined as comprising (i.e., open language, not excluding other elements or steps). The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
Drawings
Fig. 1 is a schematic side view of a cylindrical expansion tank.
Fig. 2a is a 3D view of a rectangular expansion tank.
Fig. 2b is a 3D view of two housing parts of a rectangular expansion tank.
Figure 2c is a 3D view of a cross section of a rectangular expansion tank with a diaphragm.
Figure 2d is a schematic cross-sectional view of a rectangular expansion tank with a diaphragm.
Detailed Description
Fig. 1 is a schematic side view of a cylindrical expansion tank with a first housing part 1 'and a second housing part 2'.
Fig. 2a is a 3D view of a rectangular expansion tank. In fig. 2b, the first housing part 1 and the second housing part 2 are shown.
Figure 2c is a 3D view of a cross section of a rectangular expansion tank with a diaphragm. In the figure a first housing part 1, a second housing part 2 and a membrane 3 are shown.
Figure 2d is a schematic cross-sectional view of a rectangular expansion tank with a diaphragm. The first housing part 1, the second housing part 2, the membrane 3 and the peripheral edge 4 of the membrane are shown. The rim 4 is configured to be clamped between the first housing part 1 and the second housing part 2 of the expansion tank.
Examples
An expansion tank diaphragm is produced by the steps of: the material for the membrane is heated in an extruder to a temperature of 210 ℃, the material or mixture of materials is injection molded into a membrane mold at a pressure of 140 bar within about 1 to 4 seconds, the mixture is cooled in the membrane mold and the membrane is removed from the mold.
According to NEN 13831:2007, diaphragms with a thickness between 1mm and 2.5mm and a diameter of about 30cm were subjected to cyclic pressure tests. The durability was determined by repeating the cyclic pressure test 1000 times, then filling the gas side of the container with air to 1.5 bar. If the pressure drop in the next hour does not exceed 0.15 bar, the test is continued for another 500 cycles.
N2And H2The determination of the O permeation rate was performed separately from the cycling test. Using a method of measuring N in a test apparatus2And H2Combined permeation test of O diffusion over time. In the experimental setup, a diaphragm was placed between a vacuum chamber and a chamber filled with water and pressurized nitrogen. The diffusion rate was measured by measuring the change in weight and pressure over time. The pressure drop and weight versus time are calculated as the permeability coefficients of the membrane to water and nitrogen.
Table 1.
Comparative example
a and b are repeated measurements of similar composition.
Material
All materials were standard commercial products.
B, BiiR: vulcanized bromobutyl rubber
SBR: vulcanized SBR rubber
TPU: polyether urethanes based on MDI (diphenylmethane diisocyanate) + PTMEG (polytetramethylene ether glycol)
SIS: a poly (styrene-isoprene-styrene) triblock copolymer having an MFI between 8.5g/10min and 18.5g/10min measured by ASTM D1238(200 ℃/5kg) and a polystyrene content between 14.0% and 17.0% by mass
PP: polypropylene, wherein the MFI as measured by ASTM D1238(200 ℃/2.16kg) is between 10g/10min and 100g/10 min.
The claims (modification according to treaty clause 19)
1. An expansion tank comprising a single layer membrane comprising a blend of a polyolefin and a non-olefin thermoplastic elastomer copolymer or a partially olefin thermoplastic elastomer copolymer.
2. The expansion tank as claimed in claim 1, wherein the non-olefin thermoplastic elastomer copolymer or the partial olefin thermoplastic elastomer copolymer is a block copolymer.
3. The expansion tank of claim 1 or 2, wherein the diaphragm has a peripheral edge configured to be clamped between a first housing portion and a second housing portion of the expansion tank.
4. Expansion tank according to any of the previous claims, wherein the polyolefin consists essentially of C2-C4A repeating unit.
5. Expansion tank according to any of the previous claims, wherein the polyolefin comprises at least 80 wt% propylene repeating units.
6. Expansion tank according to any of the previous claims, wherein the polyolefin is a polypropylene homopolymer, preferably having a melt flow index according to ASTM D1238(200 ℃/2.16kg) comprised between 5g/10min and 100g/10min, more preferably between 10g/10min and 100g/10 min.
7. The expansion tank of any one of the previous claims wherein the non-olefin thermoplastic elastomer copolymer or partially olefin thermoplastic elastomer copolymer is a styrene block copolymer.
8. The expansion tank according to claim 7, wherein the styrene block copolymer is a block copolymer of styrene and isoprene, preferably a poly (styrene-isoprene-styrene) triblock copolymer or a mixture of poly (styrene-isoprene-styrene) triblock copolymer and diblock copolymer, more preferably the MFI measured by ASTM D1238(200 ℃/5kg) is between 8g/10min and 19g/10 min.
9. The expansion tank according to claim 8, wherein the poly (styrene-isoprene-styrene) triblock copolymer has a polystyrene content of between 10 and 21 wt. -%, preferably between 12 and 19 wt. -%, most preferably between 14 and 17 wt. -%.
10. The expansion tank according to any of the preceding claims, not comprising EVOH.
11. The expansion tank of any of the previous claims, comprising no oil.
12. Expansion tank according to any of the previous claims, wherein the membrane comprises between 10 and 60 wt.%, preferably between 20 and 60 wt.%, more preferably between 25 and 55 wt.% of a non-olefinic thermoplastic elastomer copolymer or a partially olefinic thermoplastic elastomer copolymer.
13. Expansion tank according to any of the previous claims, wherein the membrane consists of:
a) from 10% to 60% by weight of a non-olefinic thermoplastic elastomer copolymer or a partially olefinic thermoplastic elastomer copolymer,
b) from 40% to 90% by weight of a polyolefin,
c) 0-20% by weight of an additive,
the total amount totals up to 100% by weight.
14. A method of making a single layer expansion tank membrane, said method comprising
a) Heating and mixing a polyolefin and a non-olefin thermoplastic elastomer copolymer or a partially olefin thermoplastic elastomer copolymer,
b) injection molding the mixture of a) into a membrane mold to form a single-layer membrane,
c) optionally cooling the membrane in a membrane mould,
d) removing the membrane from the mold.
15. Use of a styrene block copolymer for the manufacture of a single layer expansion tank membrane.
16. Use according to claim 15, wherein the styrenic block copolymer is a block copolymer of styrene and isoprene, more preferably a poly (styrene-isoprene-styrene) triblock copolymer.
Claims (17)
1. A single layer membrane for an expansion tank, the single layer membrane comprising a blend of a polyolefin and a non-olefin thermoplastic elastomer copolymer or a partially olefin thermoplastic elastomer copolymer.
2. The separator of claim 1, wherein the non-olefin thermoplastic elastomer copolymer or partially olefin thermoplastic elastomer copolymer is a block copolymer.
3. A diaphragm according to claim 1 or 2, wherein the diaphragm has a peripheral edge configured to be clamped between first and second housing portions of an expansion tank.
4. Separator according to any one of the preceding claims, wherein the polyolefin consists essentially of C2-C4A repeating unit.
5. Separator according to any one of the preceding claims, wherein the polyolefin comprises at least 80 wt% propylene repeating units.
6. Separator according to any one of the preceding claims, wherein the polyolefin is a polypropylene homopolymer, preferably having a melt flow index according to ASTM D1238(200 ℃/2.16kg) of between 5g/10min and 100g/10min, more preferably between 10g/10min and 100g/10 min.
7. A separator as claimed in any preceding claim, wherein the non-olefin thermoplastic elastomer copolymer or partially olefin thermoplastic elastomer copolymer is a styrene block copolymer.
8. Separator according to claim 7, wherein the styrene block copolymer is a block copolymer of styrene and isoprene, preferably a poly (styrene-isoprene-styrene) triblock copolymer or a mixture of poly (styrene-isoprene-styrene) triblock copolymer and diblock copolymer, more preferably the MFI measured by ASTM D1238(200 ℃/5kg) is between 8g/10min and 19g/10 min.
9. Separator according to claim 8, wherein the poly (styrene-isoprene-styrene) triblock copolymer has a polystyrene content of between 10 and 21 wt.%, preferably between 12 and 19 wt.%, most preferably between 14 and 17 wt.%.
10. Separator according to any one of the preceding claims, not comprising EVOH.
11. A membrane as claimed in any preceding claim, comprising no oil.
12. A membrane according to any preceding claim, wherein the membrane comprises between 10 and 60 wt%, preferably between 20 and 60 wt%, more preferably between 25 and 55 wt% of a non-olefinic thermoplastic elastomer copolymer or a partially olefinic thermoplastic elastomer copolymer.
13. A membrane according to any preceding claim, wherein the membrane consists of:
a) from 10% to 60% by weight of a non-olefinic thermoplastic elastomer copolymer or a partially olefinic thermoplastic elastomer copolymer,
b) from 40% to 90% by weight of a polyolefin,
c) 0-20% by weight of an additive,
the total amount totals up to 100% by weight.
14. A method of making a single layer membrane for an expansion tank, the method comprising:
a) heating and mixing a polyolefin and a non-olefin thermoplastic elastomer copolymer or a partially olefin thermoplastic elastomer copolymer,
b) injection molding the mixture of a) into a membrane mold to form a single-layer membrane,
c) optionally cooling the membrane in a membrane mould,
d) removing the membrane from the mold.
15. Use of a styrene block copolymer for the manufacture of a single layer membrane for an expansion tank.
16. Use according to claim 15, wherein the styrenic block copolymer is a block copolymer of styrene and isoprene, more preferably a poly (styrene-isoprene-styrene) triblock copolymer.
17. An expansion tank comprising a membrane according to any of claims 1-13.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2020798 | 2018-04-19 | ||
| NL2020798 | 2018-04-19 | ||
| PCT/NL2019/050231 WO2019203647A1 (en) | 2018-04-19 | 2019-04-18 | Single layer expansion tank membrane |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112041614A true CN112041614A (en) | 2020-12-04 |
Family
ID=62751508
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201980024976.3A Pending CN112041614A (en) | 2018-04-19 | 2019-04-18 | Single-layer expansion water tank diaphragm |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP3781873A1 (en) |
| CN (1) | CN112041614A (en) |
| WO (1) | WO2019203647A1 (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080017653A1 (en) * | 2003-03-05 | 2008-01-24 | Polymer & Steel Technologies Holding Company, Llc | Vessel diaphragm and method |
| US20100006532A1 (en) * | 2008-07-11 | 2010-01-14 | Teknor Apex Company | Retortable liners and containers |
| CN101701144A (en) * | 2009-10-30 | 2010-05-05 | 华南理工大学 | Sealing material and application thereof |
| CN102235563A (en) * | 2010-03-26 | 2011-11-09 | 奥拉尔(瑞士)股份公司 | Pressure equalising device for systems through which fluid flows |
| WO2013151441A2 (en) * | 2012-04-06 | 2013-10-10 | Flamco B.V. | Expansion vessel |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100209672A1 (en) | 2009-02-17 | 2010-08-19 | Yahya Hodjat | Metallic Layer Membrane |
| US8378025B2 (en) * | 2010-03-12 | 2013-02-19 | Equistar Chemicals, Lp | Adhesive composition |
| BE1020694A5 (en) | 2012-05-17 | 2014-03-04 | Covess N V | BALG SYSTEM FOR EXPANSION VESSEL. |
-
2019
- 2019-04-18 EP EP19726191.0A patent/EP3781873A1/en active Pending
- 2019-04-18 CN CN201980024976.3A patent/CN112041614A/en active Pending
- 2019-04-18 WO PCT/NL2019/050231 patent/WO2019203647A1/en active Application Filing
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080017653A1 (en) * | 2003-03-05 | 2008-01-24 | Polymer & Steel Technologies Holding Company, Llc | Vessel diaphragm and method |
| US20100006532A1 (en) * | 2008-07-11 | 2010-01-14 | Teknor Apex Company | Retortable liners and containers |
| CN101701144A (en) * | 2009-10-30 | 2010-05-05 | 华南理工大学 | Sealing material and application thereof |
| CN102235563A (en) * | 2010-03-26 | 2011-11-09 | 奥拉尔(瑞士)股份公司 | Pressure equalising device for systems through which fluid flows |
| WO2013151441A2 (en) * | 2012-04-06 | 2013-10-10 | Flamco B.V. | Expansion vessel |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2019203647A1 (en) | 2019-10-24 |
| EP3781873A1 (en) | 2021-02-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4772657A (en) | Hydrogenated block copolymer compositions | |
| WO2012164918A1 (en) | Multi-layer structure, inner liner for pneumatic tire, and pneumatic tire | |
| JP6138429B2 (en) | Multilayer structure, inner liner for tire and pneumatic tire | |
| US6926395B2 (en) | Ink tube for ink jet printer | |
| AU1672599A (en) | Compatibilized blends of non-polar thermoplastic elastomers and polar thermoplastic polymers | |
| KR20150038720A (en) | Multilayered structure, inner liner having the same, and pneumatic tire | |
| CN107646045B (en) | Hardness adjustment of thermoplastic elastomer compositions by combining thermoplastics and thermoplastic elastomers | |
| WO2012164917A1 (en) | Multi-layered structure, inner liner for pneumatic tire, and pneumatic tire | |
| WO2013042167A1 (en) | Air-impermeable film and pneumatic tire | |
| JP6807384B2 (en) | Film, molded product and film manufacturing method | |
| WO2015115346A1 (en) | Thermoplastic polymer composition having excellent gas barrier properties | |
| US8227063B2 (en) | Ink-contacting thermoplastic elastomer composition for ink jet printer | |
| CN111902279B (en) | Ethylene-alpha-olefin-nonconjugated polyene copolymer composition and laminate thereof | |
| CN112041615B (en) | Single-layer expansion water tank diaphragm | |
| CN112041614A (en) | Single-layer expansion water tank diaphragm | |
| JP3114269B2 (en) | Thermoplastic elastomer composition | |
| RU2801653C2 (en) | Single-layer membrane for expansion tank | |
| CN101307178A (en) | Epichlorohydrin rubber composition sulfidization molding products thereof | |
| US10815407B2 (en) | Rubber composition and sealing part for high pressure hydrogen apparatus using same | |
| JPH0449860B2 (en) | ||
| JP6162920B2 (en) | Run flat tire | |
| US20050074570A1 (en) | Fluoropolymer laminates | |
| US20190345322A1 (en) | Elastomeric thermoplastic pre-expansion composition comprising an elastomer and a physical blowing agent | |
| KR20190064340A (en) | Medical film with high transparency, flexibility and impact strength | |
| JP6125764B2 (en) | Inner liner and pneumatic tire |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |