Polyamide composition for borehole tool

Abstract

The present invention relates to degradable elements of borehole tools comprising a polyamide composition containing or consisting of A 40 to 100 wt.% of a thermoplastic mixture of A1 30 to 100 wt.% of water-soluble polyamide, and A2 0 to 70 wt.% of water-insoluble polyamide, and C 0 to 55 wt.% of filling and reinforcing materials, and D 0 to 5 wt.% of additives, wherein components A1 and A2 amount in total to 100 wt.% of mixture A, and wherein components A to C amount in total to 100 wt.%.

Description

[0001] POLYAMIDE COMPOSITION FOR DOWNHOLE TOOLS

[0002] TECHNICAL FIELD

[0003] The present invention relates to degradable polyamide compositions in the oil and gas industry, in particular to degradable polyamide compositions for the production of downhole tool elements. Furthermore, the present invention relates to a water-degradable polyamide composition for downhole tool elements comprising a thermoplastic blend of water-soluble polyamides and a thermoplastic blend of water-soluble and water-insoluble polyamides, in particular for use in hydraulic fracturing processes.

[0004] STATE OF THE ART

[0005] Hydrocarbon resources such as oil or natural gas are extracted by drilling (oil or natural gas wells, collectively referred to as "wells") from soils containing porous and permeable subterranean formations. Continuously drilled wells stimulate the productive layer to extract hydrocarbon resources from subterranean formations whose permeability has decreased over time and gradually become insufficient. Common stimulation methods include acid treatment and fracturing. Acid treatment increases the permeability of the productive layer by introducing a strong acid, such as hydrochloric acid or hydrogen fluoride, to dissolve the reactive components of the rock (carbonates, clay minerals, silicates, etc.). However, various problems associated with the use of strong acids have been identified.Therefore, methods for creating cracks in the productive layer using fluid pressure, also known as "fracking" or "hydraulic fracturing", are increasingly being used.

[0006] Hydraulic fracturing is a process in which fluid pressure, such as water pressure (hereafter simply referred to as "hydraulic pressure"), creates fractures in the productive layer. Generally, a vertical hole is drilled to a certain depth, then the hole is bent, and a horizontal borehole is created in an underground formation. Fracturing fluid is then injected into these wells under high pressure. The high hydraulic pressure causes fractures in the deep underground productive layer, which improves the extractability of hydrocarbons from the productive layer. Hydraulic fracturing is also suitable for the development of unconventional resources such as shale oil (oil matured in shale) and shale gas.Typically, wellbore treatment using hydraulic fracturing, i.e. the creation of fractures and perforations by hydraulic pressure using a high-pressure fluid (fracturing fluid) in the productive layer of a deep subterranean formation containing a hydrocarbon resource such as crude oil, shale oil, natural gas, or shale gas, is carried out as follows: A defined section of a wellbore is completely or partially plugged using suitable downhole tool elements, gradually isolating it from the top of the wellbore. Cracks or perforations are then created in the productive layer by injecting a fracturing fluid. The next defined section, usually ahead of the previous section (i.e., a segment closer to the ground surface), is then plugged, and another fracturing process is carried out, whereby the fracturing and perforation progress in the productive layer.This process is repeated until the required isolation, fracturing, etc. are completed.

[0007] A wellbore is drilled through a soil formation, and downhole tools such as plugs and sleeves are positioned along and within the wellbore. The plugs close and open sections of the wellbore so that a zone of the soil formation can be isolated. A sleeve opens and closes to establish fluid communication between the wellbore and the soil formation. The downhole tools isolate and connect the zone for various operations to process and produce hydrocarbons from the soil formation. When work in the zone is completed, components of the downhole tool, or even the entire downhole tool, may need to be removed.For example, a dissolvable fracturing ball that has been inserted into an opening of the downhole tool can be removed by injecting a solvent specifically into the area of ​​the dissolvable fracturing ball, reducing its ball diameter or dissolving the ball completely.

[0008] For example, such spheres, as described in U S2021 / 0254195A1, can be made from magnesium- and aluminum-based alloys to which special elements such as Sn, Ga, and In have been added. These elements are capable of breaking through the oxidation layer formed in humid environments, allowing oxidation to progress in the metal alloy until the entire sphere is eventually dissolved.

[0009] EP3115544B1 discloses a degradable rubber element for downhole tools containing 0.1 to 20 parts by mass of an acidic degradation accelerator, such as methyl-para-toluenesulfonic acid. WO2017 / 106077A1 discloses particulate phthalic acid or terephthalic acid as a temporary sealing agent, the solubility of which is controlled by adding alkaline degradation accelerators to the downhole fluid.

[0010] US2018 / 0252082A1 describes a process in which polymers are contacted with a wellbore fluid containing Lewis acids at high temperatures. In one example, polyamide 6 is sufficiently degraded with zinc chloride or aluminum chloride in water at 150 °C for seven days.

[0011] Sealing elements made of aggregates of polylactic acid spheres and polylactic acid powders in a polyvinyl alcohol shell are described in US2018 / 0346800A1. After dissolving the shell, the aggregate can be flushed with a borehole fluid.

[0012] US9856411 B2 discloses downhole tools made of polyhexahydrotriazines that can be dissolved by hydrochloric acid. The polymer of 4,4'-oxydianiline and formaldehyde is stable at pH values ​​greater than 3, while it depolymerizes at a pH value below 2.

[0013] US8231947B2 and US8567494B2 describe downhole tools, e.g., so-called "diverting balls" made of a material with a water-soluble core and a water-insoluble shell, the core being accessible to the borehole fluid through openings. Embodiments based on two different metals as well as embodiments with two different polymers are described.

[0014] US2010 / 0200235A1 discloses sealing spheres as drilling tool elements made of carboxylic acids, fatty alcohols, fatty acid esters, and / or fatty acid salts. These sealing agents are dissolved by raising the temperature of the borehole fluid, so that the spheres soften and eventually melt when their melting point is exceeded. The example cited is solid spheres made of sebacic acid.

[0015] Oil and gas production can involve a wide range of conditions with very different temperatures, pressures and fluid environments.

[0016] For the temporary sealing of wells, sealing agents are particularly in demand that can seal a defined section of the well for up to 12 days and then ideally dissolve without residue. Since the conditions during oil and gas production can vary widely in terms of temperature, pressure, and fluid environments, different drilling tool sealing devices (e.g., fracturing balls) are required to achieve defined sealing times.

[0017] Especially at temperatures below 120 °C, many common materials used to manufacture downhole tool plugs degrade insufficiently quickly, resulting in inefficient treatment times in the corresponding wellbore sections. On the other hand, some downhole tool plugs require the use of special, sometimes aggressive and environmentally harmful downhole fluids or the addition of such additives to the downhole fluid to dissolve the plug materials. Ideally, however, the downhole tool plugs should be dissolvable using water, groundwater, or seawater.

[0018] OBJECT OF THE INVENTION

[0019] It is therefore an object of the present invention to provide a degradable polyamide composition for the production of downhole tool elements that is sufficiently rapidly degradable by water, particularly at temperatures below 120°C. In particular, it is preferred if the polyamide composition is degradable in an aqueous medium at pH values ​​in the range of 4 to 8 and preferably at a maximum temperature of 120°C within up to 12 days. "Degradable" means that the polyamide composition can dissolve completely in the aqueous medium or that the breaking strength of the polyamide composition is reduced to such an extent that the molded bodies made of the polyamide composition disintegrate under pressure or mechanical influence. The latter is achieved when the breaking strength has dropped to below 30%, preferably below 20%, of the initial value before storage.

[0020] A further object of the present invention is to provide a downhole tool element based on a degradable polyamide composition. The aim is to be able to break the structural integrity of these elements, in particular sealing elements (e.g., plugs, frac balls, diverting agents, sealer balls), within up to 12 days using water, preferably at a maximum temperature of 120°C, so that temporarily sealed areas can be reopened.

[0021] The aim is therefore also to provide methods in which openings in a drilling line system can be temporarily closed by components of a drilling tool and in particular the closure components made of the polyamide composition according to the invention are degraded within the drilling line.

[0022] When "degradable" is used in the context of this invention, this term should be considered very broadly defined. This term can include a chemical reaction of the polymers in aqueous solution, whereby the polymers depolymerize and are thus degraded. However, "degradable" predominantly refers to disintegration, melting, softening on the outside, or a reduction in diameter.

[0023] DEFINITIONS OF TERMS

[0024] For the purposes of the present invention, the term "polyamide" (abbreviation PA) is understood as a generic term that encompasses homopolyamides and copolyamides. The chosen notations and abbreviations for polyamides and their monomers correspond to those defined in ISO standard 16396-1 (2015(D)). The abbreviations used therein are used in the following synonymously with the IIIPAC names of the monomers, in particular the following abbreviations for monomers occur: T or TPS for terephthalic acid, I or IPS for isophthalic acid, MACM for bis(4-amino-3-methyl-cyclohexyl)methane (also known as 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, CAS No. 6864-37-5), PACM for bis(4-amino-cyclohexyl)methane (also known as 4,4'-diaminodicyclohexylmethane, CAS No. 1761-71-3), TMDC for bis(4-amino-3,5-dimethyl-cyclohexyl)methane (also known as 3, 3', 5,5'-tetramethyl-4,4'-diaminodicyclohexylmethane, CAS No. 65962-45-0).

[0025] Compared to semi-crystalline polyamides, amorphous polyamides exhibit no or only a very low, barely detectable heat of fusion. In differential scanning calorimetry (DSC) according to ISO 11357 (2013) at a heating rate of 20 K / min, amorphous polyamides preferably exhibit a heat of fusion of less than 5 J / g, more preferably a maximum of 3 J / g, and most preferably between 0 and 1 J / g. Due to their amorphous nature, amorphous polyamides do not have a melting point.

[0026] Microcrystalline polyamides have a glass transition temperature and a melting point. However, their morphology is such that the crystallites are so small that a 2 mm thick sheet made from them is still transparent, i.e. its light transmission is at least 90% and its haze is at most 3%, measured according to ASTM D 1003-13 (2013). In differential scanning calorimetry (DSC) according to ISO 11357 (2013) at a heating rate of 20 K / min, microcrystalline polyamides preferably exhibit a latent heat of 5 to 25 J / g, more preferably 5 to 22 J / g, and most preferably 5 to 20 J / g. Semi-crystalline polyamides have a glass transition temperature and a pronounced melting point, and in differential scanning calorimetry (DSC)Differential Scanning Calorimetry (DSC) according to ISO 11357 (2013) at a heating rate of 20 K / min preferably has a heat of fusion of more than 25 J / g, particularly preferably more than 30 J / g, most particularly preferably from 30 to 80 J / g.

[0027] PRESENTATION OF THE INVENTION

[0028] This object is achieved with respect to the element of a downhole tool by the features of patent claim 1 and with respect to the method by the features of patent claims 14 and 15. The subclaims show advantageous developments.

[0029] This object is achieved according to the invention on the one hand by an element of a downhole tool comprising a polyamide composition containing or consisting of

[0030] A 40 to 100% by weight (wt.%) of a thermoplastic mixture consisting of

[0031] A1 30 to 100 wt.% water-soluble polyamide, and

[0032] A2 0 to 70 wt% non-water-soluble polyamide, and

[0033] B 0 to 55 wt.% fillers and reinforcing materials, and

[0034] C 0 to 5 wt.% additives, wherein components (A1) and (A2) add up to 100 wt.% of the mixture (A), and wherein components (A) to (C) add up to 100 wt.%.

[0035] An important advantage of the polyamide composition according to the invention is that it decomposes sufficiently quickly. For example, water hardness and pH do not significantly influence the degradation rate. Another important advantage of the polyamide composition according to the invention is that a downhole tool element made therefrom decomposes continuously from the outside to the inside when in contact with a borehole fluid, where "outside" refers to the surface of the element that is in contact with the borehole fluid. This means that the diameter or thickness of the downhole tool element consisting of or comprising the polyamide composition according to the invention is continuously reduced during degradation.

[0036] One embodiment of the present invention is that the entire downhole tool element consists of the polyamide composition according to the invention. Another embodiment of the present invention is that the parts of the downhole tool element consist of a mixture of other materials and the polyamide composition according to the invention. The proportions (and size) of the other materials are such that the inventive effect is still achieved.

[0037] For the purposes of the invention, water-soluble polyamides are those polyamides that have only carbon and nitrogen atoms or carbon, nitrogen, and oxygen atoms in the polymer main chain and that optionally carry functional groups bonded to the main chain that enable sufficient water solubility. Sufficient water solubility is present for the purposes of the invention if at least 90 percent by weight of the polyamide is soluble in distilled water (weight ratio of polyamide to water is 1:100) at 80°C within 24 hours. Specifically, the determination of whether it is a water-insoluble polyamide (A2) or a water-soluble polyamide (A1) is determined as follows: In a sealed glass vessel, 1 g of polyamide granules (diameter: 2 - 3 mm, length: 3 - 5 mm) with a water content of less than 0.5% is stirred in 100 g of deionized or distilled water at 80°C for 24 hours.The sample is then filtered through a filter element (e.g., filter paper, filter cloth, glass frit). The resulting filtrate is dried under vacuum (30 mbar, 80 °C, 72 hours), and the mass of dissolved polyamide is determined. If at least 90 percent by weight of the polyamide under investigation is dissolved (i.e., is present in the filtrate), this polyamide is defined as a water-soluble polyamide. If less than 10 percent by weight of the polyamide is dissolved, this polyamide is defined as a water-insoluble (non-water-soluble) polyamide.

[0038] The polyamide composition according to the invention preferably contains component (A) in the range from 47 to 99% by weight, component (B) in the range from 1 to 50% by weight and component (C) in the range from 0 to 3% by weight, in each case based on the sum of components (A) to (C).

[0039] Preferably, the mixture (A) contains 30 to 100 wt.% of component (A1) and 0 to 70 wt.% of component (A2).

[0040] Optionally, the thermoplastic mixture A ((component (A1) and / or component (A2)) contains at least one additive. Such additives can be helpful in the production of the thermoplastic mixture and / or influence the properties of the thermoplastic mixture. Such additives are, in particular, stabilizers, age inhibitors, antioxidants, antiozonants, processing stabilizers, processing aids, viscosity modifiers, light stabilizers, UV stabilizers, UV absorbers, inorganic heat stabilizers, in particular based on copper halides and alkali halides, organic heat stabilizers, optical brighteners, crystallization accelerators, crystallization retarders, flow aids, lubricants, glidants, mold release agents, colorants, in particular dyes, inorganic pigments, organic pigments, marking substances and mixtures.

[0041] Such additives are added to the thermoplastic mixture in an amount of up to 0.5 wt% based on the weight of the thermoplastic mixture (A).

[0042] Preferably used are water-soluble polyamides (A1) which comprise at least one ether diamine compound having 7 to 20 carbon atoms.

[0043] Likewise, preference is given to using water-soluble polyamides (A1) which comprise at least one dicarboxylic acid carrying sulfonate groups.

[0044] Furthermore, preference is given to using water-soluble polyamides (A1) which comprise at least one ether diamine compound having 7 to 20 carbon atoms and at least one dicarboxylic acid carrying sulfonate groups.

[0045] Preference is given to using water-soluble polyamides (A1) which comprise at least one ether diamine compound having 7 to 20 carbon atoms or at least one dicarboxylic acid carrying sulfonate groups or a mixture thereof.

[0046] Furthermore, preference is given to using water-soluble polyamides (A1) which comprise at least one linear-aliphatic, branched-aliphatic, cycloaliphatic and / or aromatic diamine having 2 to 36, preferably 4 to 18, particularly preferably 6 to 15 C atoms.

[0047] Furthermore, preference is given to using water-soluble polyamides (A1) which comprise at least one lactam and / or at least one aminocarboxylic acid.

[0048] Likewise preferred are water-soluble polyamides (A1) which comprise at least one sulfonate-bearing dicarboxylic acid and at least one linear-aliphatic, branched-aliphatic, cycloaliphatic and / or aromatic diamine having 2 to 36, preferably 4 to 18, particularly preferably 6 to 15, carbon atoms, and at least one lactam and / or one aminocarboxylic acid. Likewise preferred are water-soluble polyamides (A1) which comprise at least one sulfonate-bearing dicarboxylic acid and at least one linear-aliphatic, branched-aliphatic, cycloaliphatic and / or aromatic diamine having 2 to 36, preferably 4 to 18, particularly preferably 6 to 15, carbon atoms, and at least one lactam and / or one aminocarboxylic acid, and at least one additive.

[0049] Component (B) can be either water-soluble or water-insoluble. Water-soluble embodiments of component (B) are particularly preferred.

[0050] Component (A1) - Water-soluble polyamides

[0051] Four types of polyamides are particularly preferred among the water-soluble polyamides (A1). The first preferred type of water-soluble polyamide is characterized in that the water-soluble polyamide (A1) comprises at least one ether diamine compound having 7 to 20 carbon atoms. Particular preference is given to polyamides (A1) that comprise at least one ether diamine compound having 7 to 20 carbon atoms and at least one dicarboxylic acid having 6 to 12 carbon atoms, as well as optionally other diamines, dicarboxylic acids, lactams, or aminocarboxylic acids.

[0052] Preferably, the at least one ether diamine compound is selected from the group consisting of 4-oxaheptane-1,7-diamine, 4,7-dioxadecane-1,10-diamine, 4,7-dioxa-5-methyl-decane-1,10-diamine, 6-oxa-undecane-1,11-diamine, 4,8-dioxa-undecane-1,11-diamine, 4,8-dioxa-5-methyl-undecane-1,11-diamine, 4,8-dioxa-5,6-dimethyl-undecane-1,11-diamine, 4,9-dioxadodecane-1,12-diamine, 4,7,10-trioxa-tridecane-1,13-diamine, 4,7,10-T rioxa-5,8-dimethyltridecane-1,13-diamine, 4,11-dioxatetradecane-1,14-diamine, 4,7,11-trioxa-tetradecane-1,14-diamine, 4,7,10,13-tetraoxa-hexadecane-1,16-diamine, 4,7,10,13,16-pentaoxanonadecane-1,19-diamine and 4,17-dioxa-eicosane-1,20-diamine.

[0053] Particularly preferably, the first preferred type of water-soluble polyamide (A1) can be prepared by polycondensation from the following monomer components:

[0054] (a11) at least one linear aliphatic, branched aliphatic, cycloaliphatic and / or aromatic dicarboxylic acid having 6 to 12 C atoms; and

[0055] (b11) 25-100 mol%, based on the sum of the molar amounts of the monomer components (b11)+(b12)+(b13), of at least one diamine selected from the group consisting of 4-oxaheptane-1,7-diamine, 4,7-dioxadecane-1,10-diamine, 4,7-dioxa-5-methyl-decane-1,10-diamine, 6-oxa-undecane-1,11-diamine, 4,8-dioxa-undecane-1,11-diamine, 4,8-dioxa-5-methyl-undecane-1,11-diamine, 4,8-dioxa-5,6-dimethyl-undecane-1,11-diamine, 4,9-dioxadodecane-1,12-diamine, 4,7,10-trioxa-tridecane-1,13-diamine, 4,7,10-trioxa-5,8-dimethyl-tridecane-1,13-diamine, 4,11-dioxatetradecane-1,14-diamine, 4,7, 11-trioxa-tetradecane-1, 14-diamine, 4,7, 10,13-T etraoxa-hexadecane-1, 16-diamine, 4,7,10,13,16-pentaoxanonadecane-1,19-diamine and 4,17-dioxa-eicosane-1,20-diamine; and

[0056] (b12) 0-50 mol%, based on the sum of the molar amounts of the monomer components (b11)+(b12)+(b13), of at least one linear-aliphatic, branched-aliphatic, cycloaliphatic and / or aromatic diamine having 2 to 36, preferably 4 to 18, particularly preferably 6 to 15 C atoms; and

[0057] (b13) 0-50 mol%, based on the sum of the molar amounts of the monomer components (b11)+(b12)+(b13), of at least one compound from the group consisting of oligooxyethylenediamines, polyoxyalkylenediamines and polyalkylene glycols; and

[0058] (c11) 0-45 mol% of at least one lactam and / or at least one aminocarboxylic acid; wherein the molar amount of the monomer component (a11) relative to the sum of the molar amounts of the monomer components (b11)+(b12)+(b13) has a molar ratio in the range of 0.95 to 1.05, and wherein the proportion of the monomer component (c11) relates to the molar sum of all monomer components (a11)+(b11)+(b12)+(b13)+(c11) forming the at least one water-soluble polyamide (A1).

[0059] Particularly preferably, the first type of water-soluble polyamide (A1) consists only of the components (a11), (b11) and (b12).

[0060] The second preferred type of water-soluble polyamide (A1) is characterized in that the water-soluble polyamide (A1) comprises at least one dicarboxylic acid bearing sulfonate groups, wherein the sulfonate group may also be present in the form of its alkali metal salts. The dicarboxylic acid bearing sulfonate groups is preferably a sulfonated phthalic acid, sulfonated naphthalenecarboxylic acid, sulfonated isophthalic acid, or sulfonated terephthalic acid. Particular preference is given to 2-sulfoterephthalic acid, 4-sulfo-2,6-naphthalenecarboxylic acid, 5-sulfoisophthalic acid, or their alkali metal salts.

[0061] The second preferred type of a water-soluble polyamide (A1) is thus characterized in that the water-soluble polyamide (A1) comprises at least one dicarboxylic acid carrying sulfonate groups and diamines having 4 to 20 carbon atoms and optionally further diamines, dicarboxylic acids, lactams or aminocarboxylic acids.

[0062] Particularly preferred polyamides (A1) are those which comprise at least one sulfonated phthalic acid, sulfonated naphthalenecarboxylic acid, sulfonated isophthalic acid or sulfonated terephthalic acid, in particular 2-sulfo-terephthalic acid, 4-sulfo-2,6-naphthalenecarboxylic acid, 5-sulfo-isophthalic acid or alkali metal salts thereof, and diamines having 4 to 20 carbon atoms and optionally further diamines, dicarboxylic acids, lactams or aminocarboxylic acids.

[0063] Particularly preferred embodiments of the second type are water-soluble, sulfonate-group-bearing polyamides (A1) which are obtainable from the following monomer components: at least one linear-aliphatic, branched-aliphatic, cycloaliphatic and / or aromatic diamine having 2 to 36, preferably 4 to 18, particularly preferably 6 to 15 C atoms

[0064] (a21) 0.5 to 40 mol% of at least one linear aliphatic, branched aliphatic, cycloaliphatic and / or aromatic dicarboxylic acid having 6 to 12 C atoms; and

[0065] (a22) 5 to 50 mol% of at least one sulfonate-group-bearing dicarboxylic acid; and

[0066] (b22) 5 to 50 mol% of at least one linear aliphatic, branched aliphatic, cycloaliphatic and / or aromatic diamine having 2 to 36, preferably 4 to 18, particularly preferably 6 to 15 C atoms; and

[0067] (c21) 0-89.5 mol% of at least one lactam and / or at least one aminocarboxylic acid; wherein the sum of the molar proportions of the monomers (a21) and (a22) essentially corresponds to the molar proportion of the monomer (b22). Essentially means that the sum of the molar amounts of the monomer components (a21) and (a22) relative to the molar amounts of the monomer component (b22) has a molar ratio in the range of 0.95 to 1.05, and wherein the proportion of the monomer component (c21) refers to the molar sum of all monomer components (a21)+(a22)+(b22)+(c21) forming the at least one water-soluble polyamide.

[0068] Particularly preferably, the second type of water-soluble polyamide (A1) consists only of the components (a21), (a22) and (b22).

[0069] The third preferred type of water-soluble polyamide (A1) is characterized in that the water-soluble polyamide (A1) comprises at least one ether diamine compound having 7 to 20 carbon atoms and at least one sulfonate-containing dicarboxylic acid and at least one linear aliphatic, branched aliphatic, cycloaliphatic, and / or aromatic diamine having 2 to 36, preferably 4 to 18, particularly preferably 6 to 15 carbon atoms, as well as optionally further diamines, dicarboxylic acids, lactams, or aminocarboxylic acids. Preference is given to water-soluble polyamides (A1) of the third type obtainable from the following monomer components:

[0070] (a31) 0 to 40 mol% of at least one linear aliphatic, branched aliphatic, cycloaliphatic and / or aromatic dicarboxylic acid having 6 to 12 C atoms; and

[0071] (a32) 5 to 50 mol% of at least one sulfonate-group-bearing dicarboxylic acid; and

[0072] (b31) 5 to 50 mol% of at least one diamine selected from the group consisting of

[0073] 4-oxaheptane-1,7-diamine, 4,7-dioxadecane-1, 10-diamine, 4,7-dioxa-5-methyl-decane-1,10-diamine, 6-oxa-undecane-1,11-diamine, 4,8-dioxa-undecane-1,11-diamine, 4,8-dioxa-

[0074] 5-methyl-undecane-1,11-diamine, 4,8-dioxa-5,6-dimethyl-undecane-1,11-diamine, 4,9-dioxa-dodecane-1,12-diamine, 4,7,10-trioxa-tridecane-1,13-diamine, 4,7,10-trioxa-5,8-dimethyl-tridecane-1 , 13-diamine, 4,11-dioxatetradecan-1, 14-diamine, 4,7, 11-trioxa-tetradecan-1, 14-diamine, 4,7, 10,13-tetraoxa-hexadecane-1, 16-diamine, 4,7,10,13,16- Pentaoxanonadecane-1,19-diamine and 4,17-dioxa-eicosane-1,20-diamine; and

[0075] (b32) 0.5 to 40 mol% of at least one linear-aliphatic, branched-aliphatic, cycloaliphatic and / or aromatic diamine having 2 to 36, preferably 4 to 18, particularly preferably 6 to 15 C atoms; and

[0076] (c31) 0-89.5 mol% of at least one lactam and / or at least one aminocarboxylic acid; wherein the sum of the molar proportions of the monomers (a31) and (a32) essentially corresponds to the sum of the molar proportions of the monomers (b31) and (b32). Essentially means that the sum of the molar amounts of the monomer components (a31) and (a32) relative to the sum of the molar amounts of the monomer components (b31) and (b32) has a molar ratio in the range of 0.95 to 1.05, and wherein the proportion of the monomer component (c31) refers to the molar sum of all monomer components (a31)+(a32)+(b31)+(b32)+(c31) forming the at least one water-soluble polyamide.

[0077] The fourth preferred type of water-soluble polyamide (A1) is characterized in that the water-soluble polyamide (A1) comprises at least one linear aliphatic, branched aliphatic, cycloaliphatic and / or aromatic dicarboxylic acid; and at least one linear aliphatic, branched aliphatic, cycloaliphatic and / or aromatic diamine having 2 to 36, preferably 4 to 18, particularly preferably 6 to 15 C atoms; and at least one dicarboxylic acid bearing sulfonate groups; and at least one lactam and / or at least one aminocarboxylic acid and optionally further diamines, dicarboxylic acids, lactams or aminocarboxylic acids.

[0078] Preference is given to water-soluble polyamides (A1) of the fourth type which are obtainable from the following monomer components: (a41) 5 to 35 mol% of at least one linear-aliphatic, branched-aliphatic, cycloaliphatic and / or aromatic dicarboxylic acid having 6 to 12 C atoms; and

[0079] (a42) 10 to 40 mol% of at least one sulfonate-group-bearing dicarboxylic acid; and

[0080] (b42) 15 to 45 mol% of at least one linear-aliphatic, branched-aliphatic, cycloaliphatic and / or aromatic diamine having 2 to 36, preferably 4 to 18, particularly preferably 6 to 15 C atoms; and

[0081] (c41) 10 to 70 mol% of at least one lactam and / or at least one aminocarboxylic acid; wherein the sum of the molar proportions of the monomers (a41) and (a42) essentially corresponds to the sum of the molar proportions of the monomers (b42). Essentially means that the sum of the molar amounts of the monomer components (a41) and (a42) relative to the sum of the molar amounts of the monomer components (b42) has a molar ratio in the range of 0.95 to 1.05, and wherein the proportion of the monomer component (c41) refers to the molar sum of all monomer components (a41)+(a42)+(b42)+(c41) forming the at least one water-soluble polyamide.

[0082] Preferably, the fourth preferred type of water-soluble polyamide (A1) does not contain any ether diamine compounds.

[0083] Preferred dicarboxylic acids (a11), (a21), (a31) and (a41) are selected from the group consisting of adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, dimer fatty acid (36 C atoms), trans-cyclohexane-1,4-dicarboxylic acid, cis- or trans-cyclohexane-1,3-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, terephthalic acid and isophthalic acid.

[0084] Particularly preferred dicarboxylic acids (a11), (a21), (a31) and (a41) are selected from the group consisting of adipic acid, sebacic acid, terephthalic acid, isophthalic acid or a mixture of such dicarboxylic acids.

[0085] Preferred sulfonate group-bearing dicarboxylic acids (a22), (a32) and (a42) are selected from the group consisting of sulfonated phthalic acid, sulfonated naphthalenecarboxylic acid, sulfonated isophthalic acid or sulfonated terephthalic acid.

[0086] Particularly preferred sulfonate group-bearing dicarboxylic acids (a22), (a32) and (a42) are selected from the group consisting of 2-sulfo-terephthalic acid, 4-sulfo-2,6-naphthalenecarboxylic acid, 5-sulfo-isophthalic acid or their alkali metal salts. Preferred ether diamines (b11), (b21) and (b31) are selected from the group consisting of 4-oxaheptane-1,7-diamine, 4,7-dioxadecane-1,10-diamine, 4,7-dioxa-5-methyl-decane-1,10-diamine, 6-oxa-undecane-1,11-diamine, 4,8-dioxa-undecane-1,11-diamine, 4,8-dioxa-5-methyl-undecane-1,11-diamine, 4,8-dioxa-5,6-dimethyl-undecane-1,11-diamine, 4,9-dioxadodecane-1,12-diamine, 4,7,10-trioxa-tridecane-1,13-diamine, 4,7,10-T rioxa-5,8-dimethyl-tridecane-1, 13-diamine, 4,11-dioxatetradecane-1,14-diamine, 4,7,11-trioxa-tetradecane-1,14-diamine, 4,7,10,13-tetraoxa-hexadecane-1,16-diamine, 4,7,10,13,16-pentaoxanonadecane-1,19-diamine and 4,17-dioxa-eicosane-1,20-diamine.

[0087] Preferred diamines (b12), (b22), (b32) and (b42) are selected from the group consisting of 1,4-butanediamine, 1,5-pentanediamine, 2-methyl-1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, m ethyl-1,8-octanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, cyclohexanediamine, 1,3-bis-(aminomethyl)-cyclohexane (BAC), isophoronediamine (IPDA), norbornanedimethylamine, 4,4'-diaminodicyclohexylmethane (PACM), 2,2-(4,4'- Diaminodicyclohexyl)propane (PACP) and 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane (MACM), m-xylylenediamine (MXDA), p-xylylenediamine (PXDA) or a mixture of such diamines.

[0088] Particularly preferred diamines (b12), (b22), (b32) and (b42) are selected from the group consisting of 1,6-hexanediamine, 1,10-decanediamine, 1,12-dodecanediamine, or a mixture of such diamines is preferred. Particularly preferred diamines (b12), (b22), (b32) and (b42) are selected from the group consisting of 1,6-hexanediamine and 1,10-decanediamine.

[0089] Preferred lactams or aminocarboxylic acids of components (d1), (c21), (c31) and (c41) are aminoundecanoic acid, aminododecanoic acid, aminocaproic acid, caprolactam and laurolactam.

[0090] All water-soluble polyamides (A1) disclosed above can contain up to 0.5 wt.%, based on the weight of the water-soluble polyamide (A1), of at least one additive. If at least one such additive is present, it is preferably present in an amount of 0.01-0.5 wt.%, based on the weight of the water-soluble polyamide (A1).

[0091] The additives optionally present in the water-soluble polyamides (A1) are preferably selected from the group consisting of stabilizers, age inhibitors, antioxidants, antiozonants, processing stabilizers, processing aids, viscosity modifiers, light stabilizers, UV stabilizers, UV absorbers, inorganic heat stabilizers, in particular based on copper halides and alkali halides, organic heat stabilizers, optical brighteners, crystallization accelerators, crystallization retarders, flow aids, lubricants, slip agents, mold release agents, colorants, in particular dyes, inorganic pigments, organic pigments, marking substances and mixtures.

[0092] The polyamides (A1) have a solution viscosity RV (r| rei), measured according to ISO 307 (2007) on solutions of 0.5 g polymer in 100 ml m-cresol at a temperature of 20 °C, preferably in the range of 1.3 to 2.7, particularly preferably in the range of 1.4 to 2.3 and especially preferably in the range of 1.5 to 2.0.

[0093] Component (A2) - Non-water-soluble polyamides

[0094] Optionally, the polyamide composition according to the invention may contain, in addition to the water-soluble polyamides (A1), further polyamides (A2) that are not water-soluble. The polyamides (A2) may be present in a weight fraction of up to 70% based on the mixture of (A1) and (A2). The content of polyamide (A2) in the mixture (A) is preferably 0 to 60% by weight.

[0095] These polyamides (A2) can be either semicrystalline or amorphous. The amorphous polyamides preferably have a glass transition temperature of at least 90 °C, particularly preferably of at least 110 °C. The semicrystalline polyamides preferably have a melting point of at least 150 °C, preferably of at least 200 °C. An example of an amorphous polyamide (A2) is the copolyamide composed of 65 mol% hexamethylenediammonium isophthalate and 35% hexamethylenediammonium terephthalate. Examples of semi-crystalline representatives are polycaprolactam (nylon 6), poly(hexamethylene adipamide) (nylon 6,6), poly(hexamethylene sebacamide) (nylon 6,10), poly(hexamethylene decamethylene amide) (nylon 612), poly(m-xylylene adipamide) (MXD6), poly(p-xylylene sebacamide) (PXD10), poly(11-amino-undecanoic acid) (nylon 11) or polylaurolactam (nylon 12).

[0096] One embodiment of the present invention provides that aliphatic polyamides are preferred as component (A2). Particular preference is given to aliphatic polyamides selected from the group consisting of PA 46, PA 6, PA 66, PA 6 / 66, PA 10, PA 11, PA 12, PA 516, PA 610, PA 612, PA 614, PA 616, PA 618, PA 1010, PA 1012, PA 1014, PA 1016, PA 1018, PA 1212, and mixtures thereof. Particular preference is given to aliphatic polyamides with an N / C ratio (N = nitrogen / C = carbon) of less than or equal to 9, since they have higher water absorption and thus contribute to faster disintegration of the molded bodies. Particularly preferred are the aliphatic polyamides PA46, PA 56, PA 66, PA 610, PA 6, PA 69 and mixtures and copolymers thereof.

[0097] According to a further embodiment of the present invention, amorphous or microcrystalline polyamides are preferred as component (A2).Insbesondere bevorzugt ausgewählt sind amorphe oder mikrocristalline Polyamide aus der Gruppe bestehend aus PA 6I / 6T, PA MACM9, PA MACM10, PA MACM12, PA MACM13, PA MACM14, PA MACM16, PA MACM 17, PA MACM 18, PA PACM10, PA PACM12, PA PACM13, PA PACM14, PA PACM16, PA PACM17, PA PACM18, PA TMDC10, PA TMDC12, PA TMDC13, PA TMDC14, PA TMDC16, PA TMDC17, PA TMDC18, PA MACM10 / 10, PA MACMI / 12, PA MACMT / 12, PA 6I / MACMI / MACMT, PA MACMI / MACMT / 12, PA MACMI / MACMT / MACM12, PA MACMI / MACMT / MACM12 / 12, PA 6I / 6T / MACMI / MACMT / 12, PA 6I / 6T / MACMI, PA MACMI / MACM36, PA MACMT / MACM36, PA MACMI / MACM12, PA MACMT / MACM12, PA MACM6 / 11 PA MACM 10 / 10, PA MACM12 / PACM12, PA MACM14 / PACM14, PA MACM18 / PACM18 and Mischungen daraus, wobei PA 6I / 6T, PA MACM12, PA MACM14, PA TMDC12, PA TMDC14, PA MACMI / 12, PA 6I / 6T / MACMI / MACMT, PA MACMI / MACMT / 12, PA MACMI / MACMT / MACM12, PA 6I / 6T / MACMI / MACMT / 12, PA MACM 10 / 10, PA MACM12 / PACM12, PA MACM14 / PACM14, PA MACM18 / PACM18 und Mischungen daraus.Very particular preference is given to PA 6I / 6T, PA MACM 12, PA MACMI / 12, PA MACMI / MACMT / 12, PA MACMI / MACMT / MACM12, PA MACM12 / PACM12 and mixtures thereof.

[0098] According to a further preferred embodiment, semi-crystalline, semi-aromatic polyamides are preferred as component (A2). The semi-crystalline, semi-aromatic polyamides preferably have a glass transition temperature in the range from 90 to 150°C, preferably in the range from 110 to 140°C, and in particular in the range from 115 to 135°C. The melting point of the semi-crystalline, semi-aromatic polyamides is in the range from 255 to 330°C, preferably in the range from 270 to 325°C, and in particular in the range from 280 to 320°C. The semi-crystalline, semi-aromatic polyamides of component (A2) preferably have enthalpies of fusion, determined by DSC according to ISO 11357 (2013), in the range from 25 to 80 J / g, preferably in the range from 30 to 70 J / g.

[0099] Preferred semi-aromatic, semi-crystalline polyamides are

[0100] (a): Dicarboxylic acids: 30 to 100 mol%, in particular 50 to 100 mol% of terephthalic acid and 0 to 70 mol%, in particular 0 to 50 mol% of at least one aliphatic dicarboxylic acid having 6 to 16 carbon atoms, and / or 0 to 70 mol%, in particular 0 to 50 mol% of at least one cycloaliphatic dicarboxylic acid having 8 to 20 carbon atoms, and / or 0 to 50 mol% of isophthalic acid, in each case based on the total amount of the dicarboxylic acids,

[0101] (b): Diamines: 80 to 100 mol% of at least one aliphatic diamine with 4-18

[0102] Carbon atoms, preferably with 6 to 12 carbon atoms and 0 to 20 mol% of at least one cycloaliphatic diamine, preferably with 6 to 20 carbon atoms, such as PACM, MACM, IPDA and / or 0 to 20 mol% of at least one araliphatic diamine, such as MXDA and PXDA, based on the total amount of the diamines, and optionally

[0103] (c): Aminocarboxylic acids and / or lactams: each containing 6 to 12 carbon atoms.

[0104] According to a preferred embodiment, the semi-crystalline, semi-aromatic polyamide of component (A2) is formed on the basis of at least 55 mol%, in particular at least 65 mol% of terephthalic acid and at least 80 mol%, preferably at least 90 mol%, in particular at least 95 mol% of aliphatic diamines having 4 to 18 carbon atoms, preferably having 6 to 12 carbon atoms, and optionally further aliphatic, cycloaliphatic and aromatic dicarboxylic acids and also lactams and / or aminocarboxylic acids.

[0105] According to a further preferred embodiment, the aliphatic dicarboxylic acids of the semi-aromatic polyamide of component (A2), for example, which can be used in addition to terephthalic acid, are selected from the group consisting of adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, and dimer fatty acid (36 carbon atoms). Particular preference is given to adipic acid, sebacic acid, and dodecanedioic acid. Dicarboxylic acids that are preferably used in addition to terephthalic acid are accordingly isophthalic acid, adipic acid, sebacic acid, and dodecanedioic acid, or a mixture of such dicarboxylic acids. Polyamides (A2) based exclusively on terephthalic acid as the dicarboxylic acid are particularly preferred.

[0106] According to a further preferred embodiment, the said aliphatic diamines of the semi-aromatic polyamide of component (A2) are selected from the group 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, methyl-1,8-octanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, or a mixture of such diamines, with 1,6-hexanediamine, 1,10-decanediamine, 1,12-dodecanediamine, or a mixture of such diamines being preferred, and with 1,6-hexanediamine and 1,10-decanediamine being particularly preferred. In addition to the aliphatic diamines, cycloaliphatic and / or araliphatic diamines can be replaced in a concentration of 0 to 20 mol%, based on the total amount of diamines.

[0107] Furthermore, the polyamides (A2) are preferably formed from the following components: (a): Dicarboxylic acids: 50 to 100 mol% terephthalic acid, 0 to 50 mol% of an aliphatic

[0108] Dicarboxylic acid, preferably having 6 to 12 carbon atoms, and / or a cycloaliphatic dicarboxylic acid having preferably 8 to 20 carbon atoms, and / or isophthalic acid, in each case based on the total content of dicarboxylic acids present;

[0109] (b): Diamines: 80 to 100 mol% of at least one aliphatic diamine having 4 to 18

[0110] Carbon atoms, preferably with 6 to 12 carbon atoms, based on the total content of diamines present, 0 to 20 mol% of cycloaliphatic diamines, preferably with 6 to 20 carbon atoms, such as PACM, MACM, IPDA and / or araliphatic diamines, such as MXDA and PXDA, wherein in the high-melting polyamides the percentage molar content of dicarboxylic acids is 100% and the percentage molar content of diamines is 100%, and optionally from:

[0111] (c): Aminocarboxylic acids and / or lactams, containing lactams with preferably 6 to 12

[0112] carbon atoms, and / or aminocarboxylic acids with preferably 6 to 12 carbon atoms.

[0113] While components (a) and (b) are preferably used in substantially equimolar amounts, the concentration of (c) is preferably at most 30% by weight, preferably at most 20% by weight, in particular at most 15% by weight, in each case based on the sum of (a) to (c).

[0114] Suitable cycloaliphatic dicarboxylic acids are cis- and / or trans-cyclohexane-1,4-dicarboxylic acid and / or cis- and / or trans-cyclohexane-1,3-dicarboxylic acid (CHDA). The above-mentioned, generally used aliphatic diamines can be replaced by other diamines in minor amounts of not more than 20 mol%, preferably not more than 15 mol%, and in particular not more than 10 mol%, based on the total amount of diamines. Examples of cycloaliphatic diamines that can be used include cyclohexanediamine, 1,3-bis(aminomethyl)cyclohexane (BAC), isophoronediamine (IPDA), norbornanedimethylamine, 4,4'-diaminodicyclohexylmethane (PACM), 2,2-(4,4'-diaminodicyclohexyl)propane (PACP), and 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane (MACM). Examples of araliphatic diamines include m-xylylenediamine (MXDA) and p-xylylenediamine (PXDA).

[0115] In addition to the dicarboxylic acids and diamines described, lactams and / or aminocarboxylic acids can also be used as polyamide-forming components (component (c)). Suitable compounds include, for example, caprolactam (CL), α,w-aminocaproic acid, α,w-aminononanoic acid, α,w-aminoundecanoic acid (AUA), laurolactam (LL), and α,w-aminododecanoic acid (ADA). The concentration of the aminocarboxylic acids and / or lactams used together with components (a) and (b) is at most 20 wt.%, preferably at most 15 wt.%, and particularly preferably at most 12 wt.%, based on the sum of components (a) to (c). Lactams or α,w-amino acids having 4, 6, 7, 8, 11, or 12 C atoms are particularly preferred. These are the lactams pyrrolidin-2-one (4 C atoms), e-caprolactam (6 C atoms), enanthlactam (7 C atoms), capryllactam (8 C atoms), laurolactam (12 C atoms) and the a.cu-Amino acids 1,4-aminobutanoic acid, 1,6-aminohexanoic acid, 1,7-aminoheptanoic acid, 1,8-aminooctanoic acid, 1,11-aminoundecanoic acid, and 1,12-aminododecanoic acid. In a particularly preferred embodiment, component (A2) is free of caprolactam or aminocaproic acid or free of any aminocarboxylic acid or any lactam.

[0116] To control the molar mass, the relative viscosity or the flowability or the MVR, regulators in the form of monocarboxylic acids or monoamines can be added to the batch and / or the precondensate (before post-condensation).Aliphatic, cycloaliphatic or aromatic monocarboxylic acids or monoamines suitable as regulators are acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, lauric acid, stearic acid, 2-ethylhexanoic acid, cyclohexanoic acid, benzoic acid, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoic acid, 3,5-di-tert-butyl-4-hydroxybenzoic acid, 3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propanoic acid, 2-(3,5-di-tert-butyl-4-hydroxybenzylthio)acetic acid, 3,3-bis(3-tert-butyl-4-hydroxyphenyl)butanoic acid, butylamine, pentylamine, hexylamine, 2-ethylhexylamine, n-octylamine, n-dodecylamine, n-tetradecylamine, n-Hexadecylamine, stearylamine, cyclohexylamine, 3-(cyclohexylamino)-propylamine, methylcyclohexylamine, dimethylcyclohexylamine, benzylamine, 2-phenylethylamine, 2,2,6,6-tetramethylpiperidin-4-amine, 1,2,2,6,6-pentamethylpiperidin-4-amine, 4-amino-2,6-di-tert-butylphenol, etc. The regulators can be used individually or in combination.Other monofunctional compounds that can react with an amino or acid group, such as anhydrides, isocyanates, acid halides, or esters, can also be used as regulators. The typical amount of regulators used is between 10 and 200 mmol per kg of polymer.

[0117] Specific representatives of the partially crystalline partially aromatic polyamides (A2) are: PA 4T / 4I, PA 4T / 6I, PA 5T / 5I, PA 6T / 6, PA 6T / 6I, PA 6T / 6I / 6, PA 6T / 66, 6T / 610, 6T / 612, PA 61710T, PA 617101, PA 9T, PA 10T, PA 12T, PA 1017101, PA10T / 106, PA10T / 610, PA10T / 612, PA10T / 66, PA10T / 6, PA10T / 1010, PA10T / 1012, PA10T / 12, PA10T / 11, PA 6T / 9T, PA 6D / 12D, PA 617101761, PA 6T / 6I / 6, PA 61761 / 12, and mixtures thereof. The partially aromatic polyamide of component (A1) is particularly preferably selected from the group: PA 6T / 6I, PA 6T / 10T, PA 6T / 10T / 6I, and mixtures thereof. Preference is given to polyamides (A2) containing 6T units, in particular at least 10 wt. % of 6T units.

[0118] According to the invention, the following semi-aromatic copolyamides are particularly preferred as polyamides (A2): • semi-crystalline polyamide 6T / 6I with 55 to 75 mol% of hexamethylene terephthalamide units and 25 to 45 mol% of hexamethylene isophthalamide units;

[0119] • semi-crystalline polyamide 6T / 6I with 62 to 73 mol% hexamethylene terephthalamide units and 25 to 38 mol% hexamethylene isophthalamide units;

[0120] • semi-crystalline polyamide, produced from at least 50 mol% terephthalic acid and at most 50 mol% isophthalic acid, in particular from 100 mol% terephthalic acid, and a mixture of at least two diamines selected from the group consisting of hexamethylenediamine, nonanediamine, methyloctanediamine and decanediamine;

[0121] • semi-crystalline polyamide made from 70-100 mol% terephthalic acid and 0-30 mol% isophthalic acid and a mixture of hexamethylenediamine and dodecanediamine;

[0122] • semi-crystalline polyamide, made from at least 50 mol% terephthalic acid and at most 50 mol% dodecanedioic acid and a mixture of at least two diamines selected from the group consisting of hexamethylenediamine, nonanediamine, methyloctanediamine and decanediamine;

[0123] • semi-crystalline polyamide 6T / 10T with 10 to 60 mol%, preferably 10 to 40 mol% of hexamethylene terephthalamide (6T) and 40 to 90 mol%, preferably 60 to 90 mol% of decamethylene terephthalamide (10T) units;

[0124] • semi-crystalline polyamide 6T / 10T / 6I with 50 to 90 mol%, preferably 50-70 mol% of hexamethylene terephthalamide (6T) units, and 5 to 45 mol%, preferably 10-30 mol% of hexamethylene isophthalamide (6I) units and 5 to 45 mol%, preferably 20-40 mol% of decamethylene terephthalamide (10T) units;

[0125] The polyamides (A2) have a solution viscosity RV (r| rei), measured according to ISO 307 (2007) on solutions of 0.5 g polymer in 100 ml m-cresol at a temperature of 20 °C, preferably in the range of 1.3 to 3.0, particularly preferably in the range of 1.5 to 2.7 and especially preferably in the range of 1.6 to 2.5.

[0126] Component (B) - reinforcing fibers, particulate fillers

[0127] The molding compositions may further contain particulate fillers and / or reinforcing fibers in amounts of 0 to 55 percent by weight, in particular in amounts of 1 to 50 percent by weight, based on the sum of components (A) to (C).

[0128] Component (B) can be water-soluble or water-insoluble. Component (B) is water-soluble within the meaning of the present invention if more than 50 percent by weight of (B) dissolves in distilled water at 80°C within 24 hours. The weight ratio of (B) to distilled water is 1:100. If less than 20 percent by weight is dissolved, (B) is referred to as water-insoluble within the context of the invention.

[0129] Examples of suitable particulate fillers (B) are calcium carbonate, talc, mica, silicate, quartz, titanium dioxide, wollastonite, kaolin, amorphous silica, magnesium carbonate, chalk, lime, feldspar, barium sulfate, ground glass fibers, glass flakes or glass beads.

[0130] Particularly preferably, the particulate fillers of component (B) are alkaline earth oxides or alkaline earth hydroxides or mixtures thereof. The alkaline earth oxides or alkaline earth hydroxides are preferably selected from magnesium hydroxide, calcium hydroxide (slaked lime), calcium oxide, magnesium oxide, or mixtures thereof. Particular preference is given to magnesium hydroxide, magnesium oxide, and calcium oxide, with magnesium hydroxide and calcium oxide being especially preferred.

[0131] Examples of suitable reinforcing fibers are glass fibers, especially E-glass fibers, carbon fibers, metal fibers, potassium titanate whiskers, aramid fibers, or plastic fibers, such as polyamide fibers. The reinforcing fibers preferably have a circular cross-section and a diameter in the range of 5 to 20 micrometers, especially 6 to 13 micrometers. Glass fibers are preferably used as reinforcing fibers. The glass fibers are preferably incorporated into the polyamide composition in the form of short glass fibers, i.e., chopped glass fibers with a length of 0.1 to 12 mm, preferably 0.1 to 5 mm.

[0132] The polyamide composition according to the invention preferably contains, as component (B), fillers and / or reinforcing materials selected from the group consisting of calcium carbonate, magnesium hydroxide, calcium hydroxide, calcium oxide, magnesium oxide, talc, mica, silicate, quartz, titanium dioxide, wollastonite, kaolin, amorphous silica, magnesium carbonate, chalk, lime, feldspar, barium sulfate, ground glass fibers, glass flakes, glass beads, glass fibers, carbon fibers, metal fibers, potassium titanate whiskers, aramid fibers, or plastic fibers. The plastic fibers can be water-soluble within the meaning of the present invention.

[0133] Component (C) - Additives

[0134] Furthermore, the polyamide composition may contain up to 5% by weight, based on the sum of components (A) to (C), of additives as component (C). According to a preferred embodiment, the molding composition according to the invention contains 0 to 3% by weight, and particularly preferably 0.1 to 3% by weight, based on the sum of components (A) to (C), of at least one additive as component (C).

[0135] According to a preferred embodiment, the additives of components (C) are selected from the group consisting of stabilizers, age inhibitors, antioxidants, antiozonants, processing stabilizers, processing aids, viscosity modifiers, light stabilizers, UV stabilizers, UV absorbers, inorganic heat stabilizers, in particular based on copper halides and alkali halides, organic heat stabilizers, optical brighteners, crystallization accelerators, crystallization retarders, flow aids, lubricants, slip agents, mold release agents, colorants, in particular dyes, inorganic pigments, organic pigments, marking substances and mixtures thereof.

[0136] According to a further preferred embodiment, the molding composition according to the invention contains as component (C) at least one heat stabilizer, which is preferably present in a proportion of 0.1 to 3% by weight, based on the sum of components (A) to (C).

[0137] The invention further encompasses molded bodies made of the described polyamide composition or molded bodies having at least one region or coating made of the described polyamide composition, preferably produced by injection molding, extrusion, or compression molding. The molded bodies are preferably elements of a drilling tool comprising or consisting of the described polyamide composition.

[0138] Preferably, the element of a borehole tool is a plug, a ball, a valve, a borehole plug, an insertion aid, connecting and coupling pieces, or a guide aid (centralizing aid).

[0139] The invention also relates to a method for drilling boreholes, the method comprising the use of the described elements for borehole tools.

[0140] Preferred are methods for carrying out hydraulic fracturing processes, wherein the method comprises the use of the described elements for downhole tools.

[0141] Also preferred are methods for drilling boreholes, wherein the method comprises sealing a borehole or a perforation in a drilling tool using a downhole tool element, after which the element comprising the polyamide composition is removed within the borehole. Particularly preferred are methods for performing hydraulic fracturing processes, wherein the method comprises sealing a borehole or a perforation in a drilling tool using a downhole tool element, after which the element comprising or consisting of the polyamide composition is removed within the borehole.

[0142] WAYS OF IMPLEMENTING THE INVENTION

[0143] The invention is explained in more detail below using the following examples.

[0144] Relative viscosity

[0145] The relative viscosity (RV) was determined according to ISO 307 (2007) at 20 °C. For this purpose, 0.5 g of polymer granules were weighed into 100 ml of m-cresol. The relative viscosity (RV) was calculated using RV = t / tO based on Section 11 of the standard. Glass transition temperature (Tg) and melting point (Tm)

[0146] The glass transition temperature and melting point were determined on granules according to ISO 11357-2 and -3 (2013). Differential scanning calorimetry (DSC) was performed for each of the three heating cycles at a heating rate of 20 K / min. After the first heating cycle, the sample was cooled at a rate of 20 K / min, and the melting point was determined during the subsequent heating cycle (second heating cycle). The sample was then quenched in dry ice, and the glass transition temperature (Tg) was determined during the third heating cycle. The temperature at the peak maximum was given as the melting point. The midpoint of the glass transition range, which was given as the glass transition temperature (Tg), was determined using the half-height method.

[0147] Storage test

[0148] Five test specimens measuring 80 x 10 x 4 mm, type B (B1) according to DIN EN ISO 3167:2014-11, are stored for 15 days in a solution of 200 g distilled water and 1.8 g sodium chloride at 93.3 °C. After storage, the condition of the test specimens is examined. If the test specimens are completely dissolved or disintegrated into several individual pieces, they receive a rating of "D," otherwise "ND."

[0149] Water-soluble polyamide type 1 (WPA-1)

[0150] 59.82 kg of adipic acid, 11.62 kg of 1,6-hexanediamine, 72.55 kg of 4,7,10-trioxatridecane-1,13-diamine, and 10 kg of water were charged into a 300-liter reactor, inerted with nitrogen, and heated to 245 °C. Once this temperature was reached, the reactor was depressurized to atmospheric pressure within 1 h. The polymer melt was then held at 250 °C for a further hour with stirring, during which the reaction water was removed at atmospheric pressure by passing nitrogen over it. After 5 bar of nitrogen was applied, the reactor contents were discharged through a nozzle plate. After cooling the polymer strands on a fluidized bed, they were granulated. The resulting polyetheramide had a relative solution viscosity of 1.90, a COOH end group concentration of 40 mmol / kg, and an NFL end group concentration of 45 mmol / kg.

[0151] Water-soluble polyamide type 2 (WPA-2)

[0152] 12.46 kg of adipic acid, 41.07 kg of 1,6-hexanediamine, 25.36 kg of sodium 5-sulfoisophthalic acid, 12.85 kg of isophthalic acid, 19.80 kg of sebacic acid, and 48 kg of water were charged into a 300-liter reactor, inerted with nitrogen, and heated to 280 °C. A pressure of 20 bar was maintained for 30 minutes. The reactor was then depressurized to atmospheric pressure over a period of 2.5 hours. The polymer melt was then held at 285 °C for a further hour with stirring, during which the reaction water was removed at atmospheric pressure by passing nitrogen over it. After 5 bar of nitrogen was applied, the reactor contents were discharged through a nozzle plate. After cooling the polymer strands on a fluidized bed, they were pelletized. The formed polyamide had a relative solution viscosity of 1.65, a COOH end group concentration of 35 mmol / kg and an NH2 end group concentration of 70 mmol / kg.

[0153] Water-soluble polyamide type 4 (WPA-4a)

[0154] 11.30 kg of adipic acid, 17.97 kg of 1,6-hexanediamine, 20.73 kg of sodium 5-sulfoisophthalic acid, 17.50 kg of caprolactam, and 48 kg of water were charged into a 300-liter reactor, inerted with nitrogen, and heated to 280 °C. A pressure of 20 bar was maintained for 30 minutes. The pressure was then released to atmospheric pressure over a period of 2.5 hours. The polymer melt was then held at 285 °C for a further hour with stirring, during which the reaction water was removed at atmospheric pressure by passing nitrogen over it. After applying 5 bar of nitrogen, the reactor contents were discharged through a nozzle plate. After cooling the polymer strands on a fluidized bed, they were pelletized. The resulting polyamide had a relative solution viscosity of 1.65, a COOH end group concentration of 35 mmol / kg, and an NH2 end group concentration of 70 mmol / kg. Water-soluble polyamide type 4 (WPA-4b)

[0155] 12.38 kg of adipic acid, 19.69 kg of 1,6-hexanediamine, 22.72 kg of sodium 5-sulfoisophthalic acid, 9.59 kg of caprolactam, and 48 kg of water were charged into a 300-liter reactor, inerted with nitrogen, and heated to 280 °C. A pressure of 20 bar was maintained for 30 minutes. The reactor was then depressurized to atmospheric pressure over a period of 2.5 hours. The polymer melt was then held at 285 °C for a further hour with stirring, during which the reaction water was removed at atmospheric pressure by passing nitrogen over it. After applying 5 bar of nitrogen, the reactor contents were discharged through a nozzle plate. After cooling the polymer strands on a fluidized bed, they were pelletized. The formed polyamide had a relative solution viscosity of 1.65, a COOH end group concentration of 35 mmol / kg and an NH2 end group concentration of 70 mmol / kg.

[0156] Tab.1: Materials used in the examples and comparative examples

[0157] Production of polyamide molding compounds

[0158] For the inventive examples E1 to E9 and the comparative examples CE1 and CE2, the respective amounts of polyamide (A1), polyamide (A2), and additives (C) were metered into the feed zone of a Werner & Pfleiderer ZSK 25 twin-screw extruder according to Table 2, and any required glass fibers (B) were introduced into the melt via a side feeder in 6 barrel zones before the exit. The temperature of the first barrel was set to 70 °C, and that of the remaining barrels to 260 to 290 °C. A speed of 250 rpm and a throughput of 10 kg / h were used, and the mixture was degassed atmospherically. The strands were cooled on a cooling belt (air cooling), cut, and the resulting granules were dried at 100 °C for 24 h under vacuum (30 mbar) to a water content of less than 0.1 wt. %.

[0159] Production of the test specimens

[0160] The test specimens were produced on an Arburg Allrounder 420 C 1000-250 injection molding machine. Cylinder temperatures were increased from 260 °C to 280 °C and the mold temperature was 80 °C. Unless otherwise stated, the test specimens were used in a dry state; for this purpose, they were stored for at least 48 hours at room temperature in a dry environment, i.e., over silica gel.

[0161] Tab.2: Examples (E) and comparative examples (CE); the compositions are given below in weight percent (wt%) In addition, the test specimens E8 and E9 were compared with a commercially available magnesium-containing ring, which is frequently used as a downhole tool element.

[0162] For this purpose, the test specimens were completely immersed in an aqueous 3% KCl solution. The KCl solution maintained a constant temperature of 60°C throughout the test. All specimens were weighed at the beginning and then removed from the solution, weighed, and re-immersed in the solution at the times specified in Tables 3a, 3b, and 3c.

[0163] Table 3a: Degradation times of test specimen E8

[0164] Table 3b: Degradation times of test specimen E9

[0165] The test specimen was degraded and could no longer be weighed Table 3c: Degradation times of the magnesium-containing ring

[0166] The test specimen E8 could no longer be removed from the bath after 140 minutes due to its gel-like consistency (see Table 3a).

[0167] Table 3b shows that the test specimen E9 according to the invention has completely degraded after 235 minutes.

[0168] In contrast, the magnesium-containing ring did not dissolve sufficiently even after 335 minutes (see Table 3c).

Claims

1. An element of a borehole tool comprising a polyamide composition containing or consisting ofA 40 to 100 wt.-% of a thermoplastic mixture ofAl 130 to 100 wt.-% of water-soluble polyamide, andA2 20 to 70 wt.-% of non-water-soluble polyamide, andB 0 to 55 wt.-% of fillers or reinforcing materials, andC 0 to 5 wt.-% additives, components Al and A2 together accounting for 100 wt.-% of mixture A, and components A to C together accounting for 100 wt.-%.

2. The element of a borehole tool according to claim 1, the water-soluble polyamide Al comprising at least one ether diamine compound having 7 to 20 carbon atoms.

3. The element of a borehole tool according to claim 1, the water-soluble polyamide Al comprising at least one sulfonate group-containing dicarboxylic acid.

4. The element of a borehole tool according to claim 1, the water-soluble polyamide Al comprising at least one ether diamine compound having 7 to 20 carbon atoms and at least one sulfonate group-containing dicarboxylic acid.

5. The element of a borehole tool according to any one of the preceding claims, the water-soluble polyamide Al comprising at least one ether diamine compound having 7 to 20 carbon atoms and at least one dicarboxylic acid having 6 to 12 carbon atoms, as well as optionally further diamines, dicarboxylic acids, lactams, or aminocarboxylic acids.

6. The element of a borehole tool according to any one of the preceding claims, the water-soluble polyamide Al containing at least one ether diamine compound selected from the group consisting of 4-oxaheptane-l,7-diamine, 4,7-dioxadecane-l,10-diamine, 4,7-dioxa-5-methyl-decane -1,10-diamine, 6-oxaundecan-l,ll-diamine, 4,8-dioxaundecan-l,ll-diamine, 4,8-dioxa-5-methylundecan-l,ll-diamine, 4,8-dioxa-5,6-dimethylundecan-l,ll-diamine, 4,9-dioxadodecan -1,12-diamine, 4,7,10-trioxa-tridecan-l,13-diamine, 4,7,10-trioxa-5,8-dimethyl-tridecan-l,13-diamine, 4,11-dioxatetradecan-l,14-diamine, 4,7,11-trioxa-tetradecan -1,14-diamine, 4,7,10,13-tetraoxa-hexadecan-l,16-diamine, 4,7,10,13,16-pentaoxanonadecan-l,19-diamine and 4,17-dioxa-eicosane-l,20-diamine.

7. The element of a borehole tool according to claim 1, the water-solublepolyamide Alcomprising at least one at least one linear aliphatic, branched aliphatic, cycloaliphaticand / or aromatic dicarboxylic acid, andat least one linear aliphatic, branched aliphatic, cycloaliphatic and / or aromatic diamine with 2 to 36, preferably 4 to 18, particularly preferably 6 to 15 carbon atoms, andat least one sulfonate group-containing dicarboxylic acid, und at least one lactam and / or at least one aminocarboxylic acid, as well as optionally other diamines, dicarboxylic acids, lactams or aminocarboxylic acids.

8. The element of a borehole tool according to any one of the preceding claims, the water-soluble polyamide Al comprising at least one sulphonated phthalic acid, sulphonated isophthalic acid, sulphonated terephthalic acid, sulphonated naphthalenedicarboxylic acid or their alkali metal salts, particularly 2-sulpho-terephthalic acid, 4-sulpho -2,6-naphthalene carboxylic acid, 5-sulpho-isophthalic acid or their alkali metal salts, as well as diamines with 4 to 20 carbon atoms and optionally further diamines, dicarboxylic acids, lactams or aminocarboxylic acids.

9. The element of a borehole tool according to any one of the preceding claims, the non-water-soluble polyamide A2 is selected asan aliphatic polyamide from the group consisting of: PA 46, PA 6, PA 66, PA 6 / 66, PA 10, PA 11, PA 12, PA 516, PA 610, PA 612, PA 614, PA 616, PA 618, PA 1010, PA 1012, PA 1014, PA 1016, PA 1018, PA 1212 and mixtures thereof;and / orpartially crystalline, partially aromatic polyamide from the group consisting of: PA 4T / 4I, PA 4T / 6I, PA 5T / 5I, PA 6T / 6, PA 6T / 6I, PA 6T / 6I / 6, PA 6T / 66, 6T / 610, 6T / 612, PA 6T / 10T, PA 6T / 10I, PA 9T, PA 10T, PA 12T, PA 10T / 10I, PA10T / 106, PA10T / 610, PA10T / 612, PA10T / 66, PA10T / 6, PA10T / 1010, PA10T / 1012, PA10T / 12, PA10T / 11, PA 6T / 9T, PA 6T / 12T, PA 6T / 10T / 6I, PA 6T / 6I / 6, PA 6T / 6I / 12 as well as mixtures thereof; and / oran amorphous or microcrystalline polyamide from the group consisting of: PA 6I / 6T, PA MACM9, PA MACM10, PA MACM12, PA MACM13, PA MACM14, PA MACM 16, PA MACM17, PA MACM 18, PA PACM10, PA PACM12, PA PACM13, PA PACM14, PA PACM16, PA PACM17, PA PACM18, PATMDC10, PATMDC12, PATMDC13, PA TMDC14, PA TMDC16, PATMDC17, PATMDC18, PA MACM10 / 10, PA MACMI / 12, PA MACMT / 12, PA 61 / MACMI / MACMT, PA MACMI / MACMT / 12, PA MACMI / MACMT / MACM12, PAMACMI / MACMT / MACM12 / 12,PA 6I / 6T / MACMI / MACMT / 12, PA 6I / 6T / MACMI, PA MACMI / MACM36, PA MACMT / MACM36, PA MACMI / MACM12, PA MACMT / MACM12, PA MACM6 / 11 PA MACM10 / 10, PA MACM12 / PACM12, PA MACM14 / PACM14, PA MACM18 / PACM18 and mixtures thereof, wherein PA 6I / 6T, PA MACM12, PA MACM14, PATMDC12, PATMDC14, PA MACMI / 12, PA 6I / 6T / MACMI / MACMT, PA MACMI / MACMT / 12, PA MACMI / MACMT / MACM12, PA 6I / 6T / MACMI / MACMT / 12, PA MACM10 / 10, PA MACM12 / PACM12, PA MACM14 / PACM14, PA MACM18 / PACM18 and mixtures thereof. PA 6I / 6T, PA MACM12, PA MACMI / 12, PA MACMI / MACMT / 12, PA MACMI / MACMT / MACM12, PA MACM12 / PACM12 and mixtures thereof are particularly preferable.

10. The element of a borehole tool according to any one of the preceding claims, the filling and / or reinforcing materials B being selected from the group consisting of calcium carbonate, magnesium hydroxide, calcium hydroxide, calcium oxide, magnesium oxide, talc, mica, silicate, quartz, titanium dioxide, wollastonite, kaolin, amorphous silicic acids, magnesium carbonate, chalk, lime, feldspar, barium sulphate, ground glass fibres, glass flakes, glass balls, glass fibres,carbon fibres, metal fibres, potassium titanate whiskers, or aramid fibres.

11. The element of a borehole tool according to any one of the preceding claims, component C being selected from the group consisting of stabilisers, ageing inhibitors, antioxidants, antiozonants, processing stabilisers, processing aids, viscosity modifiers, light stabilisers, UV stabilisers, UV absorbers, inorganic heat stabilisers, in particular based on copper halides and alkali metal halides, organic heat stabilisers, optical brighteners, crystallisation accelerators, crystallisation retarders, flow aids, lubricants, release agents, colouring agents, in particular dyes, inorganic pigments, organic pigments, marking agents and mixtures thereof.

12. The element of a borehole tool according to any one of the preceding claims, mixture A consisting of 40 to 100 wt.-% of water-soluble polyamide Al and 0 to 60 wt.-% of non-water-soluble polyamide A2.

13. The element of a borehole tool according to any one of the preceding claims, the element being a plug, a ball, a valve, a bridge plug, an applicator, connecting and coupling pieces, or a guide aid (centralisation aid).

14. A method for drilling boreholes, the method comprising the use of the elements described in one of claims 1 to 13 for downhole tools.

15. A method for performing hydraulic fracturing processes, the method comprising the use of the elements described in one of claims 1 to 13 for downhole tools.

16. A method for drilling boreholes according to claim 14, the method comprising the temporarily sealing of a borehole or perforation in a drilling tool using an element for downhole tools, after which the element comprising the polyamide composition is broken down within the borehole.

17. A method for performing hydraulic fracturing processes according to claim 15, the method comprising the temporarily sealing of a aborehole or perforation in a drilling tool using an element for a downhole tool, after which the element comprising the polyamide composition is broken down within the borehole.INTERNATIONAL SEARCH REPORT International application No. PCT / EP2024 / 064184A. CLASSIFICATION OF SUBJECT MATTER C08G 69 / 26(2006.01)1, C08G 69 / 40(2006.01)1, C08G 69 / 42(2006.01)1, E21B 33 / 12(2006.01)1, E21B 43 / 26(2006.01 )i; C08K3 / 22(2006.01)1 According to International Patent Classification (IPC) or to both national classification and IPC B. FIELDS SEARCHED Minimum documentation searched (classification system followed by classification symbols) C08K; E21B;C08G: C08L Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched Electronic data base consulted during the international search (name of data base and, where practicable, search terms used) EPO-Intemal, WPI Data C. DOCUMENTS CONSIDERED TO BE RELEVANT Category* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. X X US 2019002667 Al (KOBAYASHI TAKUMA [JP] ET AL) 03 January 2019 (2019-01-03) paragraphs [0001], [0003], [0014], [0015]; claims 1-23 paragraph [0135] - paragraph [0143]; examples 1-4 paragraphs [0042], [0043] paragraphs [0091], [0092] figures 1, 2 paragraph [0074] - paragraph [0077] US 10808077 B2 (SOLVAY SPECIALTY POLYMERS USA [US]) 20 October 2020 (2020-10-20) column 1, line 14 - line 33; claims 1-16 column 11, line 1 - column 13, line 48; examples 1-9; tables 1, 2 column 8, line 9 - line 57 1-17 1-17 X US 2018252070 Al (ZHU SHITONG S [US] ET .AL) 06 September 2018 (2018-09-06) paragraphs [0005] - [0008], [0031]; claims 1-21 paragraphs [0064], [0065]; figures 13, 14: example 3 1-17 | / | Further documents are listed in the continuation of Box C. | V | See patent family annex. * Special categories of cited documents: “A” document defining the general state of the art which is not considered to be of particular relevance “E” earlier application or patent but published on or after the international filing date “L” document which may throw doubts on priority claim(s) or which is cited to establish the publication date of another citation or other special reason (as specified) “O” document referring to an oral disclosure, use, exhibition or other means “P” document published prior to the international filing date but later than the priority date claimed “T” later document published after the international filing date or priority date and not in conflict with the application but cited to understand the principle or theory underlying the invention “X” document of particular relevance; the claimed invention cannot be considered novel or cannot be considered to involve an inventive step when the document is taken alone “Y” document of particular relevance; the claimed invention cannot be considered to involve an inventive step when the document is combined with one or more other such documents, such combination being obvious to a person skilled in the ait document member of the same patent family Date of the actual completion of the international search 22 July 2024 Date of mailing of the international search report 30 July 2024 Name and mailing address of the ISA / EP European Patent Office p.b. 5818, Patentlaan 2,2280 HV Rijswijk Netherlands (Kingdom of the) Telephone No. (+31-70)340-2040 Facsimile No. (+31-70)340-3016 Authorized officer Paulus, Florian Telephone No.