Polymer component, fluid guide device, and use of a fluid guide device

Abstract

The invention relates to a polymer component (18) for use in contact with fluid in a fluid guide device. The polymer component (18) comprises a section (22) which is in contact with media and is manufactured at least in some regions from a crosslinkable polymer material (48). The crosslinkable polymer material comprises at least one polyolefin (50) functionalized with silanes (52), where at least some of the silanes are uncrosslinked silanes, and at least one silanol condensation catalyst (62). The invention also relates to a fluid guide device (10) and to the use of a fluid guide device.

Description

[0001] Polymer component, fluid guidance device, use of a fluid guidance device

[0002] The present invention relates to the field of fluid technology. In particular, the present invention relates to a polymer component that is made at least partially from a crosslinkable polymer material, a fluid-conducting device comprising such a polymer component, and the use of such a fluid-conducting device for conducting an aqueous process fluid stream.

[0003] Fluid control systems often use polymer components that come into contact with the process fluid. For example, diaphragm valves typically use valve diaphragms made of a polymer material. During operation, valve diaphragms are subjected to significant stress, for example, due to deformation during switching operations, fluctuating pressure loads, and / or contact with potentially hot process fluids. This impairs the service life of valve diaphragms. This can also apply to other polymer components in fluid control systems.

[0004] The invention addresses the problem of extending the service life of polymer components such as valve membranes.

[0005] A first aspect of the description relates to a polymer component for fluid-contact application in a fluid-conducting device. The polymer component comprises a media-contacting section. The media-contacting section is made, at least in part, from a crosslinkable polymer material. The crosslinkable polymer material comprises at least one polyolefin functionalized with silanes, wherein at least some of the silanes are uncrosslinked silanes. The crosslinkable polymer material further comprises at least one silanol condensation catalyst. The media-contacting section is made, at least in part, from the crosslinkable polymer material. This means that the crosslinkable polymer material, as a component of the manufactured polymer component, is functionalized with uncrosslinked silanes and comprises the silanol condensation catalyst.

[0006] The inventors recognized that the crosslinkable polymer material can be used to create a polymer component with a long service life. Increasing the service life of the polymer component ultimately leads to cost savings and increased sustainability. The uncrosslinked silanes, in combination with the silanol condensation catalyst, cause the polymer component to develop a kind of "self-healing effect" during operation. Specifically, defects in the polymer material can be compensated for at the molecular level, namely by crosslinking individual main chains of the polyolefin through condensation of the silanes. The siloxane bonds formed in this process are characterized by their high flexibility. Consequently, while crosslinking compensates for defects in the polymer material, it prevents unwanted, local hardening of the polymer material, which could impair the functionality of the polymer component.The condensation of silanes typically occurs in several stages, with the existing silanes being hydrolyzed by water in a first reaction step to form silanols, i.e., hydroxysilanes. The actual condensation reaction then takes place between the silanols. In the context of a fluid-guiding device such as a diaphragm valve, this has the advantage that the wetted section of the polymer component typically comes into regular contact with water anyway. This is the case, for example, when an aqueous process fluid is used or when the fluid-guiding device is cleaned with an aqueous cleaning solution. Thus, during operation of a fluid-guiding device, conditions typically regularly exist that favor the hydrolysis of silanes and consequently the "self-healing effect" of the polymer component.

[0007] For the purposes of the disclosure, the term "media-wetted portion" refers to the portion of a polymer component that, when properly installed in a fluid-conducting device, defines the process fluid channel of the fluid-conducting device. Consequently, the media-wetted portion comes into contact with a process fluid flow during operation of the fluid-conducting device. For example, the media-wetted portion of the polymer component can be a radially inner portion of the polymer component, relative to an axis oriented perpendicular to the polymer component and passing through the center of the polymer component.

[0008] For the purposes of this disclosure, the term "polymer material" refers to a material comprising macromolecules. The mass fraction of macromolecules in the polymer material is preferably at least 80%, preferably at least 90%, and particularly preferably at least 95%.

[0009] In the context of the disclosure, the term "polyolefin" refers to a macromolecule produced from alkenes by chain polymerization.

[0010] For the purposes of the disclosure, the term "uncrosslinked silane" refers to a silanol that does not form a siloxane bond with another silanol.

[0011] For the purposes of the disclosure, the term "crosslinked silane" refers to a silanol that forms at least one siloxane bond with at least one other silanol.

[0012] A siloxane bond is a chemical bond in which the silicon atoms of two silanols are connected by an oxygen atom (Si-O-Si).

[0013] For the purposes of the disclosure, the term "silanol condensation catalyst" refers to a catalyst designed to catalyze a condensation reaction of silanols. During the condensation reaction, the silanols are crosslinked with each other, eliminating at least one water molecule and forming at least one siloxane bond.

[0014] A silanol is a silane in which the silicon atom of the silane has at least one hydroxy group as a substituent. Silanols bound to a polyolefin can have one hydroxy group, two hydroxy groups, or three hydroxy groups.

[0015] Corresponding silanols are also called monohydroxysilanes, dihydroxysilanes or trihydroxysilanes.

[0016] Preferably, the uncrosslinked silanes of the polyolefin are hydrolyzable silanes.

[0017] For the purposes of this disclosure, the term "hydrolyzable silane" refers to a silane in which none of the substituents on the silicon atom of the silane is a hydroxy group. Instead, the silicon atom of the silane contains substituents such as alkoxy groups or halides.

[0018] In some embodiments, the crosslinkable polymer material comprises as a macromolecule only the at least one polyolefin functionalized with silanes, wherein at least some of the silanes are uncrosslinked silanes.

[0019] In some other embodiments, the crosslinkable polymer material comprises, in addition to the at least one polyolefin functionalized with silanes, wherein at least some of the silanes are uncrosslinked silanes, at least one further macromolecule. The further macromolecule can, for example, be a silane-free polyolefin, i.e., a polyolefin that is not functionalized with silanes.

[0020] Preferably, the catalyst is finely dispersed in the polymer material. Particularly preferably, the catalyst and the at least one polyolefin form a homogeneous mixture.

[0021] The crosslinkable polymer material may comprise catalytically inactive particles to which the catalyst is bound. In particular, the particles are coated with the catalyst. Alternatively, the catalyst is present in the crosslinkable polymer material independently of the catalytically inactive particles.

[0022] In some preferred embodiments, the polymer component is designed as a one-piece or multi-piece valve diaphragm, i.e., as a diaphragm for a diaphragm valve. The valve diaphragm can be designed in various ways. For example, the valve diaphragm is disc-shaped. A disc-shaped valve diaphragm can be flat or curved in the unloaded state. Alternatively, the valve diaphragm can have a conical sealing projection. Such valve diaphragms are used in plug diaphragm technology (PD technology) and enable precise control of the process fluid flow. In a valve diaphragm, the crosslinkable polymer material leads to post-crosslinking, which is accompanied by a self-healing effect. This can increase the service life.

[0023] In some preferred embodiments, the polymer component is designed as a connection seal. A connection seal is a component in a fluid-conducting device that creates a fluid-tight connection between two components and prevents the leakage of process fluid between the two components. Typically, a connection seal is annular and thus has a through-opening. Preferably, the connection seal is designed as a Tri-Clamp seal. Even in conjunction with a connection seal, the crosslinkable polymer material leads to post-crosslinking, which is accompanied by a self-healing effect.

[0024] In some preferred embodiments, the polymer component is designed as a connector. Connectors, also known as fittings, are used in fluid-conducting devices to fluidically connect two or more components such as pipes, hoses, or equipment. The connector can be designed, for example, as an arcuate connector or a T-shaped connector. Even in conjunction with a connector, the crosslinkable polymer material leads to post-crosslinking, which is accompanied by a self-healing effect.

[0025] In some preferred embodiments, the polymer component is designed as a pipeline or a pipeline section. Even in conjunction with a pipeline or a pipeline section, the crosslinkable polymer material leads to post-crosslinking, which is accompanied by a self-healing effect.

[0026] In some preferred embodiments, the polymer component is designed as a valve body, in particular as a valve body for a diaphragm valve. A valve body is a three-dimensionally extended component of a valve, in particular a diaphragm valve, which defines a process fluid channel of the valve, usually together with a valve diaphragm. The valve body can have a valve seat against which a valve diaphragm can be pressed to block the process fluid channel. Even in conjunction with a valve body, the crosslinkable polymer material leads to post-crosslinking, which is accompanied by a self-healing effect.

[0027] In some preferred embodiments, the polymer component is designed as a pump diaphragm. A pump diaphragm is a component in a diaphragm pump that drives the process fluid flow through movement, particularly mechanical or pneumatic movement. The pump diaphragm serves to convey the process fluid through displacement, thereby ensuring the tightness between the pump chambers of the diaphragm pump. Even in conjunction with a pump diaphragm, the crosslinkable polymer material leads to post-crosslinking, which is accompanied by a self-healing effect.

[0028] In some preferred embodiments, the polymer component is designed as a sleeve for a butterfly valve. A sleeve for a butterfly valve is a sealing element used in a butterfly valve to ensure a tight connection between the valve disc and the housing. The sleeve forms the central sealing surface that controls the process fluid flow by preventing leakage when closed and allowing flow when open. Also in the context of a sleeve for a butterfly valve, the crosslinkable polymer material leads to post-crosslinking, which is accompanied by a self-healing effect.

[0029] In some preferred embodiments, the silane-functionalized polyolefin is a polyethylene or a polypropylene. These polyolefins have the advantage of being easy to process, for example, by injection molding. Furthermore, polyethylene and polypropylene have the advantage of being fluorine-free. Polyethylene and polypropylene are therefore preferred over polytetrafluoroethylene (PTFE), for example, due to the general effort to avoid or reduce the use of fluorine-containing macromolecules.

[0030] In some preferred embodiments, the uncrosslinked silanes are trialkoxysilanes. Trialkoxysilanes are well-suited as silanes due to their reaction kinetics with respect to hydrolysis by water. Furthermore, trialkoxysilanes have the advantage that the polymer component is not damaged by the alcohols released during hydrolysis. Trimethoxysilanes are particularly preferred as uncrosslinked silanes.

[0031] In some other embodiments, the hydrolyzable silanes are trihalosilanes. Mixed-substituted silanes are also possible.

[0032] In some preferred embodiments, the silanes are chemically bonded to the main chains of the polyolefin by ethyl units. Thus, an ethyl unit is present between the main chains and the silicon atoms of the silanes. With regard to the synthesis route, this embodiment of the polyolefins is typically achieved by subsequently chemically bonding vinylsilanes to the main chains of the polyolefin. This process is referred to as silane grafting and can be initiated by a radical initiator, in particular a peroxide, preferably dicumyl peroxide. Silane grafting has the advantage that the silanes are spatially accessible for a subsequent condensation reaction. Furthermore, the amount of silanes in the polyolefin can be precisely controlled.For example, additional vinylsilane monomers can be added to the reaction mixture until a desired amount of silanes in the polyolefin is reached.

[0033] In some preferred embodiments, the silanes are chemically bonded directly to the main chains of the polyolefin. With regard to the synthesis route, this embodiment is typically achieved by including vinylsilane monomers as starting materials in the reaction mixture during the synthesis of the polyolefin. This has the advantage of reducing the number of synthesis steps. The silane-functionalized polyolefin can be synthesized, in particular, in a one-pot reaction.

[0034] In some preferred embodiments, the silanol condensation catalyst comprises a metal carboxylate. Metal carboxylates can effectively reduce the activation energy of the condensation reaction of silanols. Tin(IV) carboxylates have proven particularly suitable. The silanol condensation catalyst preferably comprises a dialkyltin(IV) dicarboxylate, particularly preferably dibutyltin dilaurate. However, metal carboxylates other than tin(IV) carboxylates can also be used as catalysts. In some other embodiments, the silanol condensation catalyst comprises an organofunctionalized sulfonic acid.

[0035] In some preferred embodiments, the degree of crosslinking of the silanes in the polyolefin is at most 1. The degree of crosslinking of the silanes refers to the ratio "crosslinked silanes / uncrosslinked silanes." Consequently, with a degree of crosslinking of 1, the number of crosslinked silanes corresponds to the number of uncrosslinked silanes. Preferably, the degree of crosslinking of the silanes is at least 0.1 and at most 1. With a degree of crosslinking of 0.1, the number of uncrosslinked silanes is 10 times greater than the number of crosslinked silanes.

[0036] In some preferred embodiments, the mass fraction of silanes in the polyolefin, based on the total mass of the polyolefin, is at least 0.1% and at most 5.0%. This mass fraction of silanes allows defects in the crosslinkable polymer material to be effectively compensated for over the service life of the polymer component. Preferably, the mass fraction of silanes is at least 0.7% and at most 3.0%. The mass fraction of silanes can be determined, for example, by energy-dispersive X-ray spectroscopy (EDX) or by elemental analysis.

[0037] In some preferred embodiments, the crosslinkable polymer material has an elongation at break of at least 200%. Such an elongation at break results in a polymer component with advantageous deformability. Such deformability is particularly advantageous for a valve diaphragm or a pump diaphragm. Preferably, the crosslinkable polymer material has an elongation at break of at least 300%, more preferably an elongation at break of at least 350%. The elongation at break values ​​were determined according to ISO 37.

[0038] In some preferred embodiments, the crosslinkable polymer material has a tensile strength of at least 10 MPa. Such a tensile strength is particularly advantageous for a polymer component. This applies particularly when the polymer component is a valve membrane or a pump membrane. Preferably, the crosslinkable polymer material has a tensile strength of at least 11 MPa, more preferably a tensile strength of 11.5 MPa. The tensile strength values ​​were determined according to ISO 37.

[0039] The polymer component preferably comprises a mounting section by means of which the polymer component can be mounted on a component of a fluid conducting device. If the polymer component is a valve diaphragm, the component is preferably a valve body of a diaphragm valve. Relative to an axis oriented perpendicular to the polymer component, in particular perpendicular to the media-wetted section, the mounting section encloses the media-wetted section in the radial direction. The mounting section is preferably made of a material that differs from the crosslinkable polymer material of the media-wetted section. The polymer component is then a multi-part polymer component. In particular, the mounting section is made of a polymer material that is catalyst-free and / or silane-free. The mounting section is typically stationary during operation of the fluid conducting device.Consequently, the material requirements for the mounting section differ from those for the wetted section. If the mounting section and the wetted section are made of different materials, a material that is particularly suitable for the design of the mounting section can be selected for the mounting section. The mounting section and the wetted section can also be made of the same material.

[0040] In some preferred embodiments, at least the media-contacting section of the polymer component is designed in multiple layers and comprises a media-side layer and at least one dry-side layer. The media-side layer is made of the crosslinkable polymer material. The dry-side layer is made of a material different from this crosslinkable polymer material. The polymer component is therefore a multi-part polymer component, in particular a multi-part valve membrane. The multi-layer design of the polymer component allows the rheological properties of the media-contacting section to be specifically optimized. For example, the dry-side layer is made of a material, in particular a polymer material, that has a higher tensile strength than the crosslinkable polymer material of the media-side layer.

[0041] In some preferred embodiments, the polymer component is monolithically formed and consists of the crosslinkable polymer material. All sections of the polymer component are thus made entirely of the crosslinkable polymer material. This then constitutes a one-piece polymer component, in particular a one-piece valve membrane. Such a polymer component offers advantages with regard to its manufacture.

[0042] A second aspect of the description relates to a fluid-conducting device. The fluid-conducting device comprises a polymer component according to the first aspect. The media-contacting portion of the polymer component defines a process fluid channel of the fluid-conducting device.

[0043] Regarding the advantages achievable with the fluid-guiding device, reference is made to the relevant statements regarding the polymer component. The features described in connection with the polymer component can be used to further develop the fluid-guiding device.

[0044] In addition to the polymer component, the fluid conducting device can have at least one further component that defines the process fluid channel together with the polymer component. In some preferred embodiments, the fluid conducting device is a diaphragm valve. The polymer component is then a valve diaphragm of the diaphragm valve. The diaphragm valve also comprises a valve body with an opening that leads to a stationary valve seat and is closed by the valve diaphragm. The valve body and the media-wetted portion of the valve diaphragm together define the process fluid channel. The valve diaphragm is movable between an open position and a closed position. In the open position, a process fluid flow is released through the process fluid channel via the stationary valve seat. Thus, a fluid passage exists between the media-wetted portion and the valve seat.In the closed position, the process fluid flow is blocked by the contact of the wetted section of the valve diaphragm against the stationary valve seat.

[0045] In some embodiments, the valve body comprises a first valve body part and a second valve body part separate from the first valve body part, wherein the first valve body part comprises the valve seat, and wherein the second valve body part comprises the opening closed by the valve membrane. The valve membrane can be held between the first valve body part and the second valve body part. Preferably, the valve membrane is clamped between the valve body parts. The valve body parts thus apply a clamping force to the valve membrane. This increases the sealing effect between the valve membrane and the valve body parts.

[0046] Preferably, the diaphragm valve comprises an actuator operatively connected to the valve diaphragm and configured to move the valve diaphragm between the open position and the closed position.

[0047] A third aspect of the description relates to the use of a fluid conducting device, in particular a diaphragm valve, according to the second aspect for conducting, in particular for controlling, an aqueous process fluid flow.

[0048] The use of the fluid guidance device in conjunction with an aqueous process fluid stream has the advantage that the "self-healing effect" of the crosslinkable polymer material is promoted by the process fluid.

[0049] Preferably, the fluid conducting device, in particular the diaphragm valve, is used to conduct, in particular to control, an aqueous process fluid stream having a temperature of at least 60°C. At elevated temperatures, the "self-healing effect" of the crosslinkable polymer material is particularly pronounced. Preferably, the aqueous process fluid stream has a temperature of at least 80°C, more preferably a temperature of at least 80°C and at most 120°C.

[0050] Preferably, the polyolefin is a polyethylene, and the aqueous process fluid stream has a temperature of at least 80°C, more preferably a temperature of at least 80°C and at most 120°C. The use of polyethylene at such high temperatures is typically problematic due to the limited stability of polyethylene. Surprisingly, however, it has been shown that by functionalizing the polyethylene with silanes and adding the silanol condensation catalyst, a sufficient increase in the stability of polyethylene can be achieved in the temperature range above 80°C.

[0051] The invention is explained in more detail below with reference to the drawings.

[0052] Fig. 1 shows a schematic sectional view of a diaphragm valve according to an embodiment;

[0053] Fig. 2 shows a perspective view of a valve membrane of the diaphragm valve shown in Figure 1;

[0054] Fig. 3 shows a sectional view of the valve membrane shown in Figure 2;

[0055] Fig. 4 shows a schematic representation of the structure of a crosslinkable

[0056] polymer material;

[0057] Fig. 5 shows a further schematic representation of the structure of the crosslinkable polymer material;

[0058] Fig. 6 shows a reaction scheme illustrating the synthesis of a silane-functionalized polyolefin;

[0059] Fig. 7 shows a reaction scheme in which a condensation reaction of

[0060] silanes;

[0061] Fig. 8 shows a diagram in which the elongation at break of the crosslinkable

[0062] polymer material; Fig. 9 shows a diagram in which the tensile strength of the crosslinkable

[0063] polymer material; and

[0064] Fig. 10 shows a sectional view of a valve membrane according to another embodiment.

[0065] Figure 1 shows a schematic sectional view of a fluid conducting device 10, which is embodied here as a diaphragm valve 10, according to one exemplary embodiment. The diaphragm valve 10 comprises a valve body 12. The valve body 14 comprises a stationary valve seat 14 and an opening 16 leading to the stationary valve seat 14.

[0066] The diaphragm valve 10 further comprises a polymer component 18, in this case an elastically deformable valve diaphragm 18. Only the valve diaphragm 18 is shown in Figures 2 and 3. The valve diaphragm 18 extends over a surface defined by two surface directions x and y. The opening 16 of the valve body 12 is closed by the valve diaphragm 18. The valve diaphragm 18 lies opposite the stationary valve seat 14. The valve body 12 and the valve diaphragm 18 together delimit a process fluid channel 20 that extends through the diaphragm valve 10. A section 22 of the valve diaphragm 18 delimiting the process fluid channel 20 is referred to below as the media-contacting section 22 of the valve diaphragm 18.

[0067] In the present embodiment, the valve body 12 is formed in several parts and comprises a first valve body part 24 and a separate second valve body part 26. The first valve body part 24 comprises a bore 28 that extends through the first valve body part 24 and delimits the process fluid channel 20 on the valve body side. The second valve body part 26 comprises the opening 16, which is closed by the valve membrane 18.

[0068] In the present case, the valve diaphragm 18 is held between the first valve body part 24 and the second valve body part 26. A section 30 of the valve diaphragm 18 arranged between the valve body parts 24 and 26 is referred to below as the mounting section 30 of the valve diaphragm 18. Relative to an axis 32 oriented perpendicular to the valve diaphragm 18, i.e. perpendicular to the surface directions x and y, and extending through the center of the valve diaphragm 18, the media-contacting section 22 is a radially inner section of the valve diaphragm 18. The mounting section 30 is a radially outer edge section of the valve diaphragm 18 that encloses the media-contacting section 22. In the embodiment shown in Figure 1, the mounting section 30 is clamped between the valve body parts 24 and 26. The valve body parts 24 and 26 therefore exert a clamping force on the mounting section 30.This increases the sealing effect between the first valve body 24 and the valve membrane 18.

[0069] In the present case, the mounting section 30 comprises a plurality of mounting openings 44 that extend through the mounting section 30. The mounting openings 44 are provided for receiving fastening elements (not shown). The fastening elements can serve to fasten the valve body parts 24 and 26 to one another. Furthermore, the fastening elements can secure the valve membrane 18 against slipping along the surface directions x, y.

[0070] The valve diaphragm 18 is movable between an open position and a closed position. In this case, the valve diaphragm 18 is moved between the open position and the closed position by deforming the media-contacting portion 22. Alternatively, the valve diaphragm 18 can also be moved between the open position and the closed position by a translational movement, in which case deformation of the valve diaphragm 18 is particularly avoided.

[0071] In the open position, the valve diaphragm 18 releases a process fluid flow through the process fluid channel 20 via the stationary valve seat 14. In the closed position, the process fluid flow is blocked by the media-wetted section 22 of the valve diaphragm 18 bearing against the valve seat 14. Figure 1 shows the valve diaphragm 18 in the open position. As can be seen from Figure 1, in the present exemplary embodiment, the valve diaphragm 18 is curved away from the valve seat 14 in the open position. Alternatively, the valve diaphragm 18 can also be curved towards the valve seat 14 in the open position or extend in a plane. The closed position of the valve diaphragm 18 is indicated by dashed lines in Figure 1.

[0072] The diaphragm valve 10 also includes an actuator 34. The actuator 34 is operatively connected to the valve diaphragm 18 and is configured to move the valve diaphragm 18 between the open position and the closed position. In this case, the actuator 34 is arranged in the opening 16 of the valve body 12.

[0073] The valve diaphragm 18 is operatively connected to the actuator 34 by an actuating rod 36. The actuator 34 introduces a force into the actuating rod 36 in order to move it along an actuating axis as indicated by the double arrow 38. In this case, the actuating axis corresponds to the axis 32, which is oriented perpendicular to the surface directions x and y and runs through the center of the valve diaphragm 18. The actuating rod 36 comprises a connecting interface 40 for force-transmitting the valve diaphragm 18 to the actuating rod 36. For example, a diaphragm pin 42 protrudes from the valve diaphragm 18 and is force-transmittingly connected to the actuating rod 36 via the connecting interface 40.

[0074] In the embodiment illustrated in Figures 1 to 3, the valve membrane 18 is monolithically formed, for example, by injection molding. The entire valve membrane 18 is made of a crosslinkable polymer material 48. The composition of the crosslinkable polymer material 48 and its material properties are explained in more detail below with additional reference to Figures 4 to 9.

[0075] Figure 4 is a schematic representation of the crosslinkable polymer material 48 directly following the manufacture of the valve membrane 18. The crosslinkable polymer material 48 comprises a polyolefin 50. In this case, the polyolefin 50 is a polyethylene. Alternatively, the polyolefin 50 can also be a polypropylene, for example. The polyolefin 50 is functionalized with silanes 52, wherein at least some of the silanes 50 are uncrosslinked. In the example shown, the silanes 52 are distributed substantially uniformly along the main chains of the polyolefin 50.

[0076] Figure 6 shows a reaction scheme in which the synthesis of the polyolefin 50 functionalized with silanes 52 is depicted in simplified form. Accordingly, a polyolefin 50, in this case polyethylene, that is not initially functionalized with silanes 52 is functionalized with silanes 52 by silane grafting. In a first reaction step (1), a peroxide, preferably dicumyl peroxide, is homolytically cleaved to form reactive initiator radicals 54. In a second reaction step (2), hydrogen atoms are transferred from the polyolefin 50 to the initiator radical 54, leaving unpaired electrons in the polyolefin 50. In a third reaction step (3), vinylsilane monomers 58 are added to the reaction mixture. The vinyl groups of the vinylsilane monomers 58 add to the polyolefin 50. In a fourth reaction step (4), the radical reaction is terminated. The polyolefin 50 functionalized with silanes 52 is obtained.The silanes 52 are bonded to the main chains of the polyolefin 50 through the ethyl units of the vinylsilane monomers 58. The type of silanes 52 is defined by the vinylsilane monomers 58 used. In this example, the vinylsilane monomers 58 are vinyltrialkoxysilanes, preferably vinyltrimethoxysilanes. Consequently, the resulting silanes 52 are trialkoxysilanes, preferably trimethoxysilanes.

[0077] Alternatively, the vinylsilane monomers 58 can also be present as monomers in the reaction mixture during the formation of the polyolefin 50. The vinylsilane monomers 58 are then integrated into the main chains of the polyolefin 52 during the formation of the polyolefin 52. Consequently, the silicon atoms of the silanes 52 are then chemically bonded directly to the main chains of the polyolefin 50.

[0078] The polymer material 48 further comprises a silanol condensation catalyst 62. In the present case, the silanol condensation catalyst 62 is a dialkyltin(IV) dicarboxylate, preferably dibutyltin dilaurate. The silanol condensation catalyst 62 is finely distributed in the crosslinkable polymer material 48. The silanol condensation catalyst 62 is not shown in Figure 4.

[0079] Figure 7 shows a reaction scheme illustrating the condensation of two silanes 52 to form a siloxane bond 60. In a fifth reaction step (5), the silanes 52 are hydrolyzed by water to form hydroxysilanes 52. Depending on the degree of hydrolysis, monohydroxysilanes, dihydroxysilanes, or trihydroxysilanes are obtained. Trihydroxysilanes are used as an example in Figure 7. The hydrolysis can be catalyzed by the silanol condensation catalyst 62. In a sixth reaction step (6), the hydroxysilanes 52 condense with one another, releasing a water molecule. The hydroxysilanes 52 thereby form a siloxane bond 60.

[0080] This leads to crosslinking of the main chains of the polyolefin 50, which are functionalized with the silanes 52 involved. The condensation reaction is catalyzed by the silanol condensation catalyst 62.

[0081] During operation of the diaphragm valve 10, the valve diaphragm 18, particularly the wetted section 22, is subjected to high stress. This stress results, for example, from the deformation of the wetted section 22 during switching operations and from the exposure of the wetted section 22 to varying pressures from the process fluid flow. Additional stress on the wetted section 22 arises when the diaphragm valve 10 is used to control a hot process fluid flow.

[0082] The stress on the media-contacting section 22 can lead to defects 64 in the polyolefin 50 at the molecular level. These defects 64 are indicated in Figure 5, where the crosslinkable polymer material 48 is shown following use of the valve membrane 18 in the diaphragm valve 10. The present composition of the crosslinkable polymer material 48 means that the defects 64 can be compensated for. Specifically, the previously described multi-stage condensation of silanes 52 with the formation of siloxane bonds 60 continuously takes place, whereby the polyolefin 50 or the crosslinkable polymer material 48 is continuously post-crosslinked. This post-crosslinking results in the original material properties of the polymer material 48 being essentially retained. Consequently, the service life of the valve membrane 18 can be extended.The water required for the hydrolysis of the silanes 52 is typically supplied to the valve membrane 18 on a regular basis anyway, namely when the process fluid is an aqueous process fluid or when the diaphragm valve 10 is cleaned with an aqueous cleaning fluid.

[0083] As can also be seen from Figure 5, the main chains of the polyolefin 50 are already crosslinked by siloxane bonds 60 directly after the production of the valve membrane 18. The presence of siloxane bonds 60 directly after production is optional and can be realized in an additional synthesis step during the production of the crosslinkable polymer material 48.

[0084] Figure 8 shows the elongation at break of the crosslinkable polymer material 48 immediately following production (0 h) and also after storage of the crosslinkable polymer material 48 in hot water at 95 °C for increasing storage times (100 h, 200 h, 300 h, 500 h, 800 h, 1000 h). As can be seen from Figure 8, the elongation at break of the polymer material 48 was above 300% in every sample tested. The elongation at break was determined according to ISO 37.

[0085] Figure 9 shows the tensile strength of the polymer material 48 immediately following production (0 h) and also following storage of the polymer material 48 in hot water at 95 °C for increasing storage times (100 h, 200 h, 300 h, 500 h, 800 h, 1000 h). As can be seen from Figure 9, the tensile strength of the polymer material 48 was above 12.0 MPa in every sample tested. The tensile strength was determined according to ISO 37.

[0086] Figure 10 shows the valve membrane 18 according to a further exemplary embodiment. In this exemplary embodiment, the valve membrane 18 is designed in multiple layers and comprises a first layer 66 arranged on the media side and a second layer 68 arranged on the dry side. When the valve membrane 18 is installed as intended in the diaphragm valve 10, the first layer 66 faces the valve seat 14. The second layer 68 faces away from the valve seat 14. In the exemplary embodiment shown in Figure 10, only the first layer 66 of the valve membrane 18 is made of the crosslinkable polymer material 48. The first layer 66 can also be referred to as a membrane shield. The second layer 68 is made of a different material, for example, a polymer material comprising a polyolefin that is not functionalized with silanes and / or does not contain a catalyst.

[0087] The invention has been explained in conjunction with the figures using the example of a valve diaphragm. However, the advantageous polymer material can also be used in other polymer components intended for fluid-contacting applications in a fluid-conducting device. Alternative polymer components include, for example, connecting seals, connectors, pipelines or pipeline sections, valve bodies, pump diaphragms, or sleeves for butterfly valves.

[0088] The invention may include the following embodiments:

[0089] Embodiment 1: A one-piece or multi-piece valve membrane (18) having a media-contacting portion (22), wherein the media-contacting portion (22) is made at least in regions from a crosslinkable polymer material (48), and wherein the crosslinkable polymer material (48) comprises: at least one polyolefin (50) functionalized with silanes (52), wherein at least some of the silanes (52) are uncrosslinked silanes (52); and at least one silanol condensation catalyst (62).

[0090] Embodiment 2: Valve membrane (18) according to embodiment 1, characterized in that the polyolefin (50) is a polyethylene or a polypropylene.

[0091] Embodiment 3: Valve membrane (18) according to one of the preceding embodiments, characterized in that the uncrosslinked silanes (52) are trialkoxysilanes, preferably trimethoxysilanes.

[0092] Embodiment 4: Valve membrane (18) according to one of the preceding embodiments, characterized in that the silanes (52) are chemically bonded to the main chains of the polyolefin (50) by ethyl units. Embodiment 5: Valve membrane (18) according to one of embodiments 1 to 3, characterized in that the silanes (52) are chemically bonded directly to the main chains of the polyolefin (50).

[0093] Embodiment 6: Valve membrane (18) according to one of the preceding embodiments, characterized in that the silanol condensation catalyst (62) comprises a meta II carboxylate, preferably a tin(IV) carboxylate, particularly preferably dibutyltin dilaurate, or an organo-functionalized sulfonic acid.

[0094] Embodiment 7: Valve membrane (18) according to one of the preceding embodiments, characterized in that the degree of crosslinking of the silanes (52) is at most 1, preferably at least 0.1 and at most 1.

[0095] Embodiment 8: Valve membrane (18) according to one of the preceding embodiments, characterized in that the mass fraction of silanes in the polyolefin (50), based on the total mass of the polyolefin (50), is at least 0.1% and at most 5.0%, preferably at least 0.7% and at most 3.0%.

[0096] Embodiment 9: Valve membrane (18) according to one of the preceding embodiments, characterized in that the crosslinkable polymer material (48) has an elongation at break of at least 200%, preferably at least 250%, particularly preferably at least 300%.

[0097] Embodiment 10: Valve membrane (18) according to one of the preceding embodiments, characterized in that the crosslinkable polymer material (48) has a tensile strength of at least 10.0 MPa, preferably at least 11.0 MPa, particularly preferably at least 11.5 MPa.

[0098] Embodiment 11: Valve membrane (18) according to one of the preceding embodiments, characterized in that the valve membrane (18) comprises a mounting section (30) by means of which the valve membrane (18) can be mounted on a valve body (12) of a diaphragm valve (10), wherein the mounting section (30) radially encloses the media-contacting section (22) with respect to an axis (32) oriented perpendicular to the valve membrane (18), and wherein the mounting section (30) is made of a material different from the crosslinkable polymer material (48).Embodiment 12: Valve membrane (18) according to one of the preceding embodiments, characterized in that at least the media-contacting section (22) of the valve membrane (18) is multi-layered and comprises a media-side layer (66) and at least one dry-side layer (68), wherein the media-side layer (66) is made of the crosslinkable polymer material (48), and wherein the dry-side layer (68) or at least one of the dry-side layers is made of a material different from the crosslinkable polymer material (48).

[0099] Embodiment 13: Valve membrane (18) according to one of embodiments 1 to 10, characterized in that the valve membrane (18) is monolithically formed and consists of the crosslinkable polymer material (48).

[0100] Embodiment 14: A diaphragm valve (10), comprising: a valve diaphragm (18) according to one of the preceding embodiments; a valve body (12) with an opening (16) which leads to a stationary valve seat (14) and which is closed by the valve diaphragm (18), wherein the valve body (12) and the media-wetted portion (22) of the valve diaphragm (18) together delimit a process fluid channel (20), and wherein the valve diaphragm (18) is movable between an open position in which a process fluid flow through the process fluid channel (20) is released via the stationary valve seat (14), and a closed position in which the process fluid flow is blocked by the media-wetted portion (22) abutting the stationary valve seat (14).

[0101] Embodiment 15: A use of the diaphragm valve (10) according to the preceding embodiment for controlling an aqueous process fluid flow.

Claims

Patent claims 1. Polymer component (18) for fluid-contact application in a fluid conducting device, wherein the polymer component (18) has a media-contacting section (22), wherein the media-contacting section (22) is made at least in regions from a crosslinkable polymer material (48), and wherein the crosslinkable polymer material (48) comprises: - at least one polyolefin (50) functionalized with silanes (52), wherein at least some of the silanes (52) are uncrosslinked silanes (52); and - at least one silanol condensation catalyst (62).

2. Polymer component (18) according to claim 1, characterized in that the polyolefin (50) is a polyethylene or a polypropylene.

3. Polymer component (18) according to one of the preceding claims, characterized in that the uncrosslinked silanes (52) are trialkoxysilanes, preferably trimethoxysilanes.

4. Polymer component (18) according to one of the preceding claims, characterized in that the silanes (52) are chemically bonded to the main chains of the polyolefin (50) by ethyl units.

5. Polymer component (18) according to one of claims 1 to 3, characterized in that the silanes (52) are chemically bonded directly to the main chains of the polyolefin (50).

6. Polymer component (18) according to one of the preceding claims, characterized in that the silanol condensation catalyst (62) comprises a meta II carboxylate, preferably a tin(IV) carboxylate, particularly preferably dibutyltin dilaurate, or an organo-functionalized sulfonic acid.

7. Polymer component (18) according to one of the preceding claims, characterized in that the degree of crosslinking of the silanes (52) is at most 1, preferably at least 0.1 and at most 1.

8. Polymer component (18) according to one of the preceding claims, characterized in that the mass fraction of silanes in the polyolefin (50), based on the total mass of the polyolefin (50), is at least 0.1% and at most 5.0%, preferably at least 0.7% and at most 3%.

9. Polymer component (18) according to one of the preceding claims, characterized in that the crosslinkable polymer material (48) has an elongation at break of at least 200%, preferably at least 250%, particularly preferably at least 300%.

10. Polymer component (18) according to one of the preceding claims, characterized in that the crosslinkable polymer material (48) has a tensile strength of at least 10.0 MPa, preferably at least 11.0 MPa, particularly preferably at least 11.5 MPa.

11. Polymer component (18) according to one of the preceding claims, characterized in that the polymer component (18) comprises a mounting section (30) by means of which the polymer component (18) can be mounted on a component of a fluid conducting device, in particular on a valve body (12) of a diaphragm valve (10), wherein the mounting section (30) radially encloses the media-contacting section (22) with respect to an axis (32) oriented perpendicular to the polymer component (18), and wherein the mounting section (30) is made of a material which is different from the crosslinkable polymer material (48).

12. Polymer component (18) according to one of the preceding claims, characterized in that at least the media-contacting section (22) of the polymer component (18) is multi-layered and comprises a media-side layer (66) and at least one dry-side layer (68), wherein the media-side layer (66) is made of the crosslinkable polymer material (48), and wherein the dry-side layer (68) or at least one of the dry-side layers is made of a material different from the crosslinkable polymer material (48).

13. Polymer component (18) according to one of claims 1 to 10, characterized in that the polymer component (18) is monolithically formed and consists of the crosslinkable polymer material (48).

14. Polymer component (18) according to one of the preceding claims, characterized in that the polymer component (18) is designed as a one-part or multi-part valve membrane (18), in particular a disc-shaped valve membrane or valve membrane with a conical sealing projection.

15. Polymer component (18) according to one of claims 1 to 13, characterized in that the polymer component (18) is designed as a connecting seal, in particular as a Tri-Clamp seal, as a connecting piece, in particular an arcuate connecting piece or T-shaped connecting piece, as a pipe or pipe section, as a valve body for a diaphragm valve, as a pump diaphragm for a diaphragm pump or as a sleeve for a butterfly valve.

16. A fluid guiding device (10) comprising: - a polymer component (18) according to one of the preceding claims, wherein the media-contacting portion (22) of the polymer component (18) delimits a process fluid channel (20) of the fluid guiding device (10).

17. Fluid guiding device (10) according to the preceding claim, characterized in that the fluid guiding device (10) is a diaphragm valve (10), and in that the polymer component (18) is a valve diaphragm (18) of the diaphragm valve (10), the diaphragm valve (10) comprising: - a valve body (12) with an opening (16) which leads to a fixed valve seat (14) and which is closed by the valve diaphragm (18), wherein the valve body (12) and the media-contacting section (22) of the valve diaphragm (18) together delimit the process fluid channel (20), and wherein the valve diaphragm (18) is movable between an open position in which a process fluid flow through the process fluid channel (20) is released via the fixed valve seat (14), and a closed position in which the process fluid flow is blocked by the media-contacting section (22) bearing against the fixed valve seat (14).

18. A use of the fluid guiding device (10) according to one of claims 16 and 17 for guiding an aqueous process fluid stream.

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