Fibre-reinforced polyamide molding material

Abstract

To provide polyamide molding materials which have excellent properties in terms of warping, impact strength and notched impact strength, tensile strength at break and elongation at break, as well as surface quality, deflection temperature under load and resistance to moulds and / or bacteria.SOLUTION: A polyamide molding material comprises A: a polymer mixture comprising A1: at least one semi-crystalline, aliphatic polyamide selected from PA6, PA46, PA56, PA66, PA66 / 6, PA610, PA612, PA6 / 12, PA1010, PA11, PA12 and the like, and A2: at least one semi-aromatic polyamide selected from PA6I, PA5I / 5T, PA6I / 6T, PA10I / 10T, PA10T / 6T, PA6T / BACT / 66 / BAC6, PA MXD6 and the like, B: reinforcing fibers, C: metal borate, and D: additives different from A, B and C, wherein the molding material includes neither copper halides nor metal phosphinates.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a fiber-reinforced polyamide molding material containing two different polyamide-reinforced fibers and a metal borate in addition to a selected polymer mixture. The present invention further relates to the use of such molding material for producing molded articles and to the molded articles themselves. [Background technology]

[0002] Polyamides are now widely used as structural elements for both internal and external applications due to their virtually outstanding mechanical properties. In particular, their mechanical properties, such as strength and rigidity, can be improved by adding fiber-reinforced materials, such as carbon fibers or glass fibers.

[0003] Patent Document 1 relates to a polyamide molding material reinforced with flattened glass fibers, which is advantageous over molding materials made from round glass fibers in terms of tear strength perpendicular to the processing direction, notched impact strength, and flow length.

[0004] Patent Document 2 describes a polyamide composition that exhibits improved thermal degradation behavior by combining a copper compound and a zinc compound. In the examples according to the present invention, the zinc compound, zinc oxide, and zinc borate are used in combination with copper iodide, which is a heat stabilizer.

[0005] Zinc compounds are often used as flame retardant additives, as described in Patent Document 3, for example. Disclosed here is a fiber-reinforced polyamide composition containing mineral boehmite and / or zinc borate as a flame retardant additive, based on a flame retardant, a semi-aromatic polyamide, and a phosphinate metal salt as a flame retardant.

[0006] However, it has been shown that conventional fiber-reinforced plastics, including polyamide molding materials containing long fibers, have not yet provided satisfactory results in all respects. Therefore, it is desirable to provide fiber-reinforced polyamide molding materials and molded parts manufactured from such materials that have excellent surface quality due to minimal warping, high rigidity and strength, and a high reinforcing fiber content. In particular, there is a growing need for molded articles made from fiber-reinforced polyamide molding materials that have superior properties compared to conventional technologies in terms of notched impact strength, heat distortion temperature (HDT), and resistance to mold or bacteria. In addition, the difference between the properties in the dry state and the packaged state should be minimal. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] European Patent No. 2060607 [Patent Document 2] International Publication No. 2014160564 [Patent Document 3] U.S. Patent Application Publication No. 2010 / 113655 [Overview of the project] [Problems that the invention aims to solve]

[0008] The problem addressed by the present invention is to identify polyamide molding materials that can be processed into molded articles, which, if possible, simultaneously possess outstanding properties in terms of warp resistance, impact strength and notched impact strength, tensile strength and elongation at fracture, as well as surface quality, temperature of deflection under load, and resistance to mold and / or bacteria. In particular, polyamide molding materials must be classified according to ISO 846:2020 (Plastics - Evaluation of Microbial Action) for mold resistance of "zero" (0), "1A" (1a) or "1" (1), and bacterial resistance of "zero" (0) or "1" (1). [Means for solving the problem]

[0009] This problem is solved with respect to the molding material according to the features of claim 1, with respect to the molded article according to the features of claim 12, and with respect to the use according to the features of claim 14. Dependent claims disclose advantageous development techniques.

[0010] According to the present invention, this problem is solved by the fiber-reinforced polyamide molding material according to claim 1, the polyamide molding material comprising the following components: A polymer mixture, A1 At least one semicrystalline aliphatic polyamide selected from the group including PA6, PA46, PA56, PA66, PA66 / 6, PA610, PA612, PA6 / 12, PA1010, PA11, PA12, PA1012, PA1212 and mixtures thereof, in an amount of 55-85% by weight. A2 consists of 15-45% by weight of at least one semi-aromatic polyamide selected from the group including PA6I, PA5I / 5T, PA6I / 6T, PA6T / 6I, PA10I / 10T, PA10T / 6T, PA6T / BACT / 66 / BAC6, PA MXD6, PA MXD6 / MXDI and mixtures thereof, and a polymer mixture of 33-79.4% by weight, where the sum of A1 and A2 is 100% by weight of A. B 20-60% by weight of reinforced fiber, C A metal borate with a molar ratio of metal to boric acid in the range of 0.5 to 4, containing 0.6 to 2.0% by weight. It consists of additives different from DA, B, and C, in amounts of 0-5.0% by weight. The sum of components A to D is 100% by weight, and the molding material does not contain either copper halides or metal phosphinates. [Modes for carrying out the invention]

[0011] For the purposes of this invention, the term "polyamide" (abbreviated PA) is understood as a general term encompassing homopolyamides and copolyamides, regardless of their molar mass or viscosity. Thus, the general term polyamide includes low molecular weight polyamides before condensation and high molecular weight homopolyamides and copolyamides after condensation. The selected spellings and abbreviations for polyamides and their monomers correspond to those specified in ISO standard 16396-1 (2015(D)). The abbreviations used in this specification are synonymous with the IUPAC names of the monomers, and in particular, abbreviations exist for the following monomers: T or TPA for terephthalic acid, I or IPA for isophthalic acid, BAC for 1,3-bis(aminomethyl)cyclohexane (CAS number 2579-20-6), and MXDA for m-xylylenediamine (CAS number 1477-55-0). Hereinafter, HMDA is used as an abbreviation for 1,6-hexanediamine, also known as hexamethylenediamine.

[0012] Compared to semicrystalline polyamides, amorphous polyamides have no detectable heat of fusion, or only a very small amount of heat of fusion that is almost undetectable. Dynamic differential calorimetry (DSC) according to ISO 11357 (2013) shows that amorphous polyamides preferably exhibit a heating rate of 20 K / min, a heat of fusion of less than 5 J / g, a maximum value of 3 J / g, and most preferably 0 to 1 J / g. Because amorphous polyamides are amorphous, they do not have a melting point.

[0013] In addition to the glass transition, semicrystalline polyamides have a significant melting point, and dynamic differential calorimetry according to ISO 11357 (2013) shows that, preferably, they have a heating rate of 20 K / min, a heat of fusion of at least 15 J / g, particularly preferably at least 20 J / g, and even more preferably in the range of 25 to 80 J / g.

[0014] Regarding the polyamide used in accordance with the present invention, the monomer of dicarboxylic acid, the monomer of diamine portion, and any aminocarboxylic acid or monofunctional regulator used form, by condensation, amide-shaped repeating units or end groups derived from the respective monomers. Generally, these are composed of at least 95 mol%, particularly at least 99 mol% of all the repeating units and end groups present in the polyamide. In addition, the polyamide may also have a small amount of other repeating units that can result from decomposition reactions or side reactions of monomers such as the monomer of diamine.

[0015] According to independent claim 1, the proposed fiber-reinforced polyamide molding material according to the present invention is characterized in that it does not contain copper halide and metal phosphinate, that is, this molding material contains neither copper halide nor metal phosphinate, and in that this molding material has a polymer mixture A that forms a polyamide matrix formed from specific starting materials A1 and A2.

[0016] The polyamide molding material according to the present invention contains, in each case, component A in a range of preferably 40.4 to 74.4% by weight, particularly preferably 46.6 to 69.25% by weight, based on the total of components A to D.

[0017] Polymer mixture A contains 55-85% by weight of at least one semicrystalline aliphatic polyamide A1 selected from the group and / or mixtures thereof, such as PA6, PA46, PA56, PA66, PA66 / 6, PA610, PA612, PA6 / 12, PA1010, PA11, PA12, PA1012, and PA1212. Polyamide A1 is preferably selected from PA6, PA56, PA66, PA66 / 6, PA610 and mixtures thereof. Preferred mixtures include, for example, PA66 and PA6, or PA610 and PA6. In addition, the polymer mixture contains, as a second component, 15 to 45% by weight of at least one amorphous semi-aromatic polyamide or semi-crystalline semi-aromatic polyamide A2 selected from the group including PA6I, PA5I / 5T, PA6I / 6T, PA6T / 6I, PA10I / 10T, PA10T / 6T, PA6T / BACT / 66 / BAC6, PA MXD6, PA MXD6 / MXDI and mixtures thereof. Preferred polyamides A2 are PA6I / 6T and PA6T / BACT / 66 / BAC6.

[0018] The ratio of component A1 is preferably in the range of 60 to 85% by weight, more preferably 65 to 80% by weight, relative to the total of components A to D in each case, and the ratio of component A2 is preferably in the range of 15 to 40% by weight, more preferably 20 to 35% by weight.

[0019] In the proposed fiber-reinforced polyamide molding material, the polyamide matrix consisting of 33 to 79.4% by weight of the above polymer mixture A is essential here, and the reinforcing fibers B, which are 20 to 60% by weight and preferably continuous fibers (long fibers or rovings), are either cut fibers (short fibers) or continuous fibers (long fibers, rovings).

[0020] The reinforcing fiber B is preferably glass fiber, basalt fiber, or carbon fiber, or a mixture thereof, with glass fiber being particularly preferred.

[0021] Particularly preferred is that the reinforcing fiber B is a continuous glass fiber (glass filament, roving).

[0022] The diameter of the suitable continuous glass fibers is 10 to 20 μm, preferably 11 to 18 μm, particularly preferably 12 to 17 μm, and even more preferably 11 to 13 μm. The continuous glass fibers may consist of all types of glass, such as D-glass, E-glass, ECR-glass, L-glass, S-glass, R-glass, or any mixture thereof. The glass fibers are preferably made from E-glass, ECR-glass, or S-glass, or from a mixture of these fibers.

[0023] Suitable glass fibers have a cross-sectional area that can be either circular (or synonymous with round) or non-circular (or synonymous with flattened), in the latter case, the dimensional ratio of the larger cross-sectional axis to the smaller cross-sectional axis is at least 2, and preferably in the range of 2 to 6.

[0024] According to a preferred embodiment of the present invention, component B is present in the polyamide molding material in an amount of 25-55% by weight, particularly preferably 30-50% by weight, and these amounts are related to the sum of components A-D.

[0025] In accordance with the present invention, it is particularly preferable to use E-glass fibers, ECR-glass fibers, and / or S-glass fibers. However, other types of glass fibers may be used, such as D-glass fibers, L-glass fibers, R-glass fibers, or any mixture thereof, or mixtures with E-glass fibers, ECR-glass fibers, and / or S-glass fibers. The reinforcing fibers, especially glass fibers, contain an adhesion promoter based on an aminosilane compound or an epoxysilane compound, and are treated with a sizing agent suitable for thermoplastics, especially polyamides.

[0026] In a preferred embodiment, component B is a high-strength glass fiber, so-called S-glass fiber. This is preferably based on a ternary silica-alumina-magnesium oxide or a quaternary silica-alumina-magnesium oxide-calcium oxide, and preferably has a composition of 58-70 wt% silica (SiO2), 15-30 wt% alumina (Al2O3), 5-15 wt% magnesium oxide (MgO), 0-10 wt% calcium oxide (CaO), and 0-2 wt% other oxides such as zirconium dioxide (ZrO2), boric acid oxide (B2O3), titanium dioxide (TiO2), iron oxide (Fe2O3), sodium oxide, potassium oxide, or lithium oxide (Li2O). In particular, it is preferable that the high-strength glass fibers have the following composition: 62-66% by weight of silica (SiO2), 22-27% by weight of alumina (Al2O3), 8-12% by weight of magnesium oxide (MgO), 0-5% by weight of calcium oxide (CaO), and 0-1% by weight of other oxides such as zirconium dioxide (ZrO2), boric acid oxide (B2O3), titanium dioxide (TiO2), iron oxide (Fe2O3), sodium oxide, potassium oxide, or lithium oxide (Li2O).

[0027] The polyamide molding material according to the present invention, which contains cut fibers (short fibers), can be manufactured by known compounding methods. The polyamide and additives are melted in an extruder, and the cut fibers are preferably introduced into the polyamide molten material and mixed with the polymer molten material. The fiber-reinforced polymer molding material is then discharged from the extruder and granulated. In this way, cylindrical granules having a length of 2 to 5 mm and a diameter of 2 to 4 mm are preferably produced.

[0028] The polyamide molding material according to the present invention, which contains continuous fibers (long fibers), can be manufactured by known methods for producing rod-shaped granules reinforced with long fibers, particularly by pultrusion, in which the continuous fiber strands (rovings) are completely impregnated with a polymer molten material, followed by cooling and cutting. Generally, the polymer components and additives are melted in an extruder and transported directly as a molten material to the impregnation unit.

[0029] The long fiber-reinforced rod-shaped granules obtained in this way, preferably with a granule length of 3 to 25 mm, and especially 4 to 12 mm, can be further processed into molded parts using conventional processing methods (injection molding, press molding), and particularly good molded part properties can be obtained by applying a gentle processing method. In this regard, gentle means that most excessive fiber breakage and the associated significant reduction in fiber length are prevented. In the case of injection molding, this means that it is preferable to use a screw with a large diameter.

[0030] Glass fibers used as continuous fibers (rovings) in the pultrusion method are subjected to a suitable sizing system made from an adhesion promoter and a film-forming agent. For example, organically functionalized silanes such as aminosilane, epoxysilane, vinylsilane, methacrylsilane, or methacryloyloxysilane can be used as adhesion promoters. For example, polyurethane, polyester urethane, polyether urethane, polyhydroxyether, epoxy resin, polyamide, acrylic polymer, or mixtures thereof are preferably used as film-forming agents.

[0031] From a materials standpoint, with respect to the composition of polymer mixture A forming the polyamide matrix, the present invention basically encompasses all combinations of aliphatic polyamides mentioned in feature A1 and semi-aromatic polyamides mentioned in feature A2. In this case, the semi-crystalline aliphatic polyamide A1 is preferably selected from PA6, PA56, PA66, PA66 / 6, PA610 and mixtures thereof. Polyamide A1 is preferably a solution viscosity η in m-cresol (0.5 g of polymer granules dissolved in 100 mL of m-cresol at 20°C) measured according to ISO 307:2007, in the range of 1.3 to 2.7, preferably in the range of 1.4 to 2.3, and particularly in the range of 1.50 to 2.00. rel It holds.

[0032] As is known from the prior art, the production of these aliphatic polyamides is brought about by polymerization or polycondensation of the corresponding lactam and / or aminocarboxylic acid and / or diamine and dicarboxylic acid, using the chain rule as necessary, preferably using monocarboxylic acid or monoamine.

[0033] For the semi-aromatic polyamide A2, the copolyamides PA6I / 6T and PA6T / BACT / 66 / BAC6 are particularly preferred. For the copolyamide PA6I / 6T, a composition range in which the ratio of 6T units is less than 50 mol% is particularly preferred, and a composition range of 6T:6I of 15:85 to 45:55 is particularly preferred. Therefore, amorphous semi-aromatic polyamide 6I / 6T(A2) having 55 to 85 mol% hexamethylene isophthalamide units and 15 to 45 mol% hexamethylene terephthalamide units is preferred.

[0034] With respect to the copolyamide PA6T / BACT / 66 / BAC6, a composition range having a ratio of 6T and BACT units that together constitute more than 60 mol%, and more preferably less than 70 mol%, is particularly preferred, and a composition range of 6T:BACT:66:BAC6 where 54-72 mol%:16-36 mol%:6-16 mol%:2-4 mol% is even more particularly preferred. In particular, a semi-crystalline semi-aromatic polyamide 6T / BACT / 66 / BAC6(A2) having 55-70 mol% hexamethylene terephthalamide units, 20-25 mol% 1,3-bis(aminomethyl)cyclohexane terephthalamide units, 6-16 mol% hexamethylene adipoamide units, and 2-4 mol% 1,3-bis(aminomethyl)cyclohexane adipoamide units is preferred.

[0035] The polymer mixture (A) has the following composition: (A1): PA66 or PA610, or a mixture of PA66 and PA6, or a mixture of PA610 and PA6, (A2): PA6I / 6T with a molar ratio in the range of 65:35 to 75:25, or especially 67:33, and (A1): PA66 or a mixture of PA66 and PA6 or PA610 and PA6, (A2): PA6T / BACT / 66 / BAC6 is preferred, where the molar ratio of 6T and BACT units is greater than 60, and preferably less than 70 mol%.

[0036] In a more preferred embodiment, the glass transition temperature of component A2 is greater than 90°C, preferably greater than 110°C, and particularly preferably 120°C.

[0037] In this case, polyamide A2 is preferably a solution viscosity η in m-cresol (0.5 g of polymer granules dissolved in 100 mL of m-cresol at 20°C) measured according to ISO 307:2007, in the range of 1.3 to 2.0, preferably in the range of 1.35 to 1.9, and particularly in the range of 1.40 to 1.8. rel It holds.

[0038] As is known from the prior art, the production of polyamide A2 is carried out by reacting a corresponding substantial molar amount of diamine and dicarboxylic acid with a chain modifier, preferably a monocarboxylic acid or monoamine, as needed.

[0039] The polyamide molding material according to the present invention also contains, in each case, at least one metal borate compound in an amount of 0.6 to 2.0% by weight, preferably 0.6 to 1.6% by weight, and particularly preferably 0.7 to 1.4% by weight, relative to the total of components A to D.

[0040] In this case, the molar ratio of boric acid to metal in the metal borate compound (B:M ratio) is in the range of 0.5 to 4, and is particularly preferably in the range of 1 to 3. The metal present with boric acid in the metal borate is preferably an alkali metal, alkaline earth metal, or transition metal, and may be present independently or in combination within the metal borate. Sodium, potassium, magnesium, calcium, barium, and zinc are particularly preferred metals. In addition, aluminum and silicon may also be present.

[0041] Suitable metal borate compositions include, for example, sodium borate, particularly pentahydrate (Na2O·2B2O3·5H2O), borax decahydrate (Na2O·2B2O3·10H2O), anhydrous borax (Na2O·2B2O3), and disodium octaborate tetrahydrate (Na2O·4B2O3·4H2O), magnesium borate (2MgO·B2O3), calcium borate (2CaO·3B2O3·5H2O), calcium metaborate (CaO·B2O3·4H2O), and hydroborasite (CaMg[B3O4( These include magnesium-calcium borate (OH3)2]·3H2O), barium metaborate (BaO·B2O3·H2O), zinc borate (xZnO·yB2O3·zH2O) such as 2ZnO·3B2O3·7H2O, 2ZnO·3B2O3·3.5H2O, 2ZnO·2B2O3·3H2O, 4ZnO·B2O3·H2O, and 2ZnO·3B2O3, calcium borate silicate, sodium borate silicate, aluminum borate silicate, aluminum borate, copper borate, and iron borate.

[0042] Regarding the object of the present invention, metal borate compounds are of the formula (ZnO) x (B2O3) Y (H2O) z It is particularly preferable that the zinc borate has the following properties. In this case, it is even more preferable that in the given formula, X takes a value in the range of 2 to 4, Y takes a value in the range of 1 to 3, and Z takes a value in the range of 0 to 5.

[0043] Various zinc borate compounds are available for sale, for example, sold by US Borax under the trademark name Firebrake®. Particularly preferred forms of zinc borate are those with X=4, Y=1 and Z=1 (Firebrake 415), X=2, Y=3 and Z=3.5 (Firebrake 290), X=2, Y=2 and Z=3 (Firebrake ZB-223), or X=2, Y=3 and Z=0 (Firebrake 500).

[0044] Equation (ZnO)2(B2O3)3(H2O) 3.3-3.7Accordingly, a zinc borate compound with a B:M ratio of 3 is particularly preferred, and (ZnO)2(B2O3)3, which is an anhydrous deformable form, is particularly preferred.

[0045] With regard to the present invention, from the viewpoint of the mechanical strength and appearance of the molded parts, the average particle size of the metal borate is preferably 30 μm or less, and particularly preferably 20 μm or less. The mechanical strength can preferably be stabilized by using metal borate powder with a particle size of 1 to 20 μm.

[0046] The polyamide molding material according to the present invention may also contain additive D as a further component in an amount of up to 5.0% by weight, preferably 0 to 3.0% by weight, and particularly preferably 0.05 to 2.0% by weight. Additive D is different from components A, B, and C. In particular, component D is also different from copper halides and metal phosphinates. This means that the polyamide molding material according to the present invention does not contain copper halides such as copper(I) iodide. Furthermore, the molding material according to the present invention does not contain any flame retardants, particularly metal phosphinates. The molding material does not contain either copper halides or metal phosphinates.

[0047] Suitable additives include, for example, inorganic stabilizers, organic stabilizers, lubricants, dyes and marking substances, inorganic pigments, organic pigments, IR absorbers, antistatic agents, antiblocking agents, crystallization inhibitors, condensation catalysts, chain adjusters, defoamers, chain extension additives, graphite, carbon nanotubes, release agents, separation agents, fluorescent dyes, phototautomorphizing additives, plasticizers, metal pigments, metal flakes, and metal coating particles. The polyamide molding material according to the present invention may contain stabilizers and / or degradation inhibitors, such as antioxidants, ozone inhibitors, light stabilizers, UV stabilizers, UV absorbers or UV blockers, heat stabilizers, and mixtures thereof.

[0048] In preferred embodiments, in addition to the stabilizers described above, component D also contains a compound selected from the group consisting of zinc oxide, zinc sulfide, zinc stearate, zinc montanoate, calcium montanoate, calcium stearate, aluminum stearate, and mixtures thereof. Furthermore, with respect to components A to D, it is preferable that these compounds are present in the molding material at a concentration of 0.05 to 0.5% by weight.

[0049] Experiments revealed that the following components in particular: A: A polymer mixture, A1 65-80% by weight of polyamide PA6, PA66, or PA610 and mixtures thereof, A2 20-35% by weight of polyamide PA6I / 6T, PA6T / BACT / 66 / BAC6 and mixtures thereof, A polymer mixture consisting of A1 and A2 totaling 100% by weight of A, with a total weight of 46.6-69.25% by weight. B: 30-50% by weight of glass long fibers (continuous glass fibers, roving), Zinc borate in a C:B:M ratio of 0.5 to 4, 0.7 to 1.4% by weight. D: Consists of 0.05 to 2.0% by weight of additives different from A, B, and C. It has also been shown that polyamide molding materials in which the sum of A to D is 100% by weight and the molding material does not contain both copper halides and phosphinate metal salts have excellent properties.

[0050] Surprisingly, it has been found that when the filled polyamide molding material according to the present invention is processed into a molded body, a molded body with average properties, particularly notched impact strength, tensile strength at fracture, elongation at fracture, temperature of deflection under load, and resistance to mold and / or bacteria, can be obtained.

[0051] Furthermore, surprisingly, it has been found that the addition of metal borates in combination with preferably used glass long fibers (continuous glass fibers) does not actually have any adverse effect on the mechanical properties of the molding material or the molded article. On the other hand, when so-called cut fibers or glass short fibers are used, drawbacks in mechanical properties, particularly in notched impact strength, tensile strength at break, and elongation at break, must be tolerated.

[0052] The glass long fibers (continuous fibers, rovings) preferably used in accordance with the present invention clearly form a web or skeleton (fiber aggregate) within the molded body by the winding of fiber fragments formed during the manufacturing of the molded body. This effectively prevents crack propagation and, as a result, contributes to shape retention at high temperatures and notched impact strength, thereby enabling outstanding properties despite the presence of additives such as pigments, including metal borates.

[0053] The fact that there is little serious damage to the glass fibers during injection molding further significantly enhances the winding of the glass fibers in the molded body. A low-viscosity polyamide matrix is ​​particularly preferable in contributing to this. Therefore, even under unfavorable conditions such as high shear during injection molding during the production of molded parts, the fiber fragments in the molded body have sufficient average length and length distribution to result in significant three-dimensional fiber aggregation and, consequently, outstanding properties.

[0054] In the case of molded materials reinforced with glass long fibers (continuous fibers, rovings) and molded articles produced from these materials, the notched impact strength at 23°C remains substantially unchanged and constant with the addition of metal borates, which is particularly noteworthy as it is substantially identical to that of molded materials without metal borates. On the other hand, when using glass short fibers, the notched impact strength at 23°C decreases by up to 40% with the addition of metal borates compared to molded materials without metal borates. Similar behavior can be observed with respect to elongation at fracture. These findings demonstrate the clear advantages of the preferred use of glass long fibers.

[0055] Uncoated fillers, such as finely ground metal borates, act as nucleating agents for semi-crystalline polyamides. This means they increase the crystallization temperature and accelerate crystallization. This often leads to undesirable embrittlement of fiber-reinforced thermoplastics. The nucleating effect of metal borates can be counteracted by suitably selecting matrix components, such as a combination of semi-crystalline aliphatic polyamide A1 and amorphous semi-aromatic polyamide A2.

[0056] The load deflection temperature (HDT-C) of the polyamide molding material according to the present invention, in accordance with ISO 75:2013, is at least 120°C, preferably at least 130°C, and particularly preferably at least 200°C.

[0057] The load deflection temperature (HDT-A) of the polyamide molding material according to the present invention, in accordance with ISO 75:2013, is at least 200°C, preferably at least 230°C.

[0058] The present invention also relates to a molded article made from the polyamide molding material described above, or a molded article having at least one region or coating made from the polyamide molding material, which is more preferably manufactured by injection molding, extrusion molding or blow molding. This is preferably a molded body in the following fields: housings, covers or frames, housings or housing components, preferably housings or housing components for portable electronic devices, cladding or covers, household appliances, household electrical appliances, eyeglass bases, eyeglass frames, sunglasses, cameras, binoculars, decorative articles, telecommunications equipment and devices and personal electrical appliances, interior and exterior components for the automotive sector and other means of transport, preferably interior and exterior components with supporting or mechanical functions in the fields of electronics, furniture, sports, mechanical engineering, facility hygiene and personal hygiene, blowers (especially blower rotors or blower wheels), pharmaceuticals, energy technology and driving technology, particularly preferably a molded body in mobile phones, smartphones, organizers, laptop computers, notebook computers, tablet computers, radios, cameras, watches, calculators, sensor housings, measuring devices, music and / or video playback devices, navigation devices, GPS devices, electrophotographic frames, external hard drives and other electronic storage media.

[0059] Preferably, the molded article meets the requirements for a germicidal surface according to Method A of DIN EN ISO 846:2020 and is classified as "zero" (0) or "1A" (1a) by testing according to the method described in Annex C. Additionally or alternatively, the molded article meets the requirements for bacterial resistance according to Method C of DIN EN ISO 846:2020 and is classified as "zero" (0) by testing according to the method described in Annex C.

[0060] The present invention also relates to the use of the described polyamide molding materials for manufacturing moldings resistant to mold and bacteria, in particular door handles, hands-free door openers, handrails, kitchen appliances, medical devices, automotive interior functional parts, handles with levers and buttons, shift levers, control units for air conditioning systems, control units for entertainment devices, door locking systems, hinges, handles, handrails and bars in public transportation, medical care beds, hospital furniture, elevator knobs and control elements, kitchen furniture, bathroom equipment and accessories, housings and covers, ventilation systems, blowers, axial fans, centrifugal fans, rotors for process fans, etc.

Examples

[0061] The present invention will be further described in detail by the following examples. The following materials were used in the examples and comparative examples. PA-1: η rel Polyamide 66 (RADICI, IT) with η = 1.82 and Tm = 262 °C PA-2: η rel Polyamide 6 (BASF, DE) with η = 1.80 and Tm = 222 °C APA-1: η rel Polyamide 6I / 6T (67:33) (EMS-CHEMIE AG, CH) with η = 1.50 and Tm = 125 °C APA-2: η rel Polyamide (6T / BACT / 66 / BAC6 (68.5 / 23.5 / 6 / 2) (EMS-CHEMIE AG, CH) with η = 1.65, Tm = 325 °C and Tg = 150 °C LGF-1: Sizing system containing E-glass roving NEG TufRov4510-17-2400, round cross-section area with a diameter of 17 μm, an aminosilane-based adhesion promoter and an epoxy resin-based film-forming agent LGF-2: Sizing system containing E-glass roving NEG TufRov4510-12-1200, round cross-section area with a diameter of 12 μm, an aminosilane-based adhesion promoter and an epoxy resin-based film-forming agent GF:ECR - Glass short fiber bundle, Vetrotex 995 EC10-4.5, Length: 4.5 mm, Filament diameter: 10 μm (Saint-Gobain Vetrotex, FR) Metallic borate: Firebrake 500, (ZnO)2(B2O3)3, M:B=3 (USBorax, USA) Stabilizer: A mixture of Irganox 1098 (BASF, DE) and Bruggolen H10 (Bruggemann, DE) in a 2:1 ratio. Zinc sulfide: Sachtolith HD-S, ZnS, Huntsman, USA

[0062] Molding materials for compositions B7-B10, B12, and B13 shown in Table 2 were manufactured using a twin-screw extruder of model ZSK 30 manufactured by Werner and Pfleiderer. Granules of compositions A1 and A2, as well as additives C and D, were weighed and supplied to the feed zone. Glass fibers (GF, glass short fibers) were weighed and supplied to the polymer molten material via a side feeder 3 housing unit in front of the nozzle. The housing temperature was set to an upward profile of 270-300°C. A throughput of 10 kg was obtained at 150-200 rpm. Granulation was performed by underwater granulation or underwater hot cut, where the polymer molten material was pressed through a perforating die and granulated by a rotating knife in a water stream immediately after being extruded from the die. After granulation and drying at 110°C for 24 hours, the granule properties were measured and test specimens were produced.

[0063] Continuous reinforcement compositions B1-B6 (Table 1) and B11 (Table 2) were manufactured by pultrusion. Polymer mixture A containing additives C and / or D was mixed with these compositions, melted in a twin-screw extruder, and then transferred to an impregnation unit for contact with preheated continuous filament glass fibers (LGF-1 and LGF-2, continuous glass fibers). More specifically, the pultrusion process was carried out as follows: Components A1, A2, C, and D were weighed and supplied to the feed zone of a twin-screw extruder with a screw diameter of 40 mm. Subsequently, the components were mixed with a temperature rise profile of 270-340°C. The extruder, securely connected to the impregnation unit, transported the molten material directly to the impregnation unit, where it was impregnated with glass fibers preheated to 180-220°C. Using a heating zone in the range of 340-400°C, continuous glass fibers were drawn through the impregnation zone at a speed of 8-15 meters per minute, with 1200 tex roving for 12 μm fibers and 2400 tex roving for 17 μm fibers. After cooling in water, the thus impregnated strands were cut to a length of 10 mm. After pelletizing and drying at 110°C for 24 hours, the properties of the pellets were measured to produce test specimens.

[0064] Test specimens were manufactured using an Arburg injection molding system with a cylinder temperature of 260°C to 300°C and a peripheral screw speed of 15 m / min. A molding temperature of 100°C to 140°C was selected.

[0065] The tests were conducted using the following test specimens, in accordance with the following standards. Elastic tensile modulus

[0066] In accordance with the ISO / CD 3167 (2003) standard, the tensile modulus of elasticity was determined according to ISO 527 (2012) using an ISO tensile rod (Type A1, size 170 × 20 / 10 × 4) at a stretching speed of 1 mm / min and 23°C. Tensile stress and elongation at fracture

[0067] In accordance with ISO / CD 3167 (2003) standards, the tensile stress and elongation at fracture were determined for an ISO tensile rod type A1 (size 170 × 20 / 10 × 4 mm) at a stretching speed of 5 mm / min and 23°C, according to ISO 527 (2012). Impact strength by Charpy

[0068] The rods were manufactured in accordance with ISO / CD 3167 (2003), and the Charpy impact strength was determined at 23°C using ISO test rod type B1 (dimensions 80 × 10 × 4 mm) according to ISO 179 / 2*eU (1997, *2 = mounting). Charpy notched shock resistance

[0069] Manufactured in accordance with ISO / CD 3167 (2003), the impact strength with a Charpy notch was determined at 23°C using ISO test rod type B1 (dimensions 80 × 10 × 4 mm) according to ISO 179 / 2*eA (1997, *2 = mounting). Melting point (T m ) and enthalpy of melting (ΔH m )

[0070] The melting point and enthalpy of fusion of the granules were determined according to DIN EN ISO 11357-3:2018. Differential scanning calorimetry (DSC) measurements were performed at a heating rate of 20 K / min. Glass transition temperature, T g

[0071] The glass transition temperature T of the granules was determined by differential scanning calorimetry (DSC) according to DIN EN ISO 11357-2:2020. g The glass transition temperature T was determined. This determination was made using a heating rate of 20 K / min for each of the two heating cycles. After the first heating, the sample was rapidly cooled with dry ice. During the second heating, the glass transition temperature T was determined. g The midpoint of the glass transition region given as the glass transition temperature was determined using the "half-height" method. Relative viscosity, η rel

[0072] The relative viscosity was determined at 20°C according to ISO307(2007). For this purpose, 0.5g of polymer granules was weighed and placed in 100mL of m-cresol, and η rel = Relative viscosity (η) according to t / t0 rel The calculation of ) was based on Section 11 of the standard. Temperature of deflection under load (HDT)

[0073] Also known as deformation temperature under load (HDT), this temperature is reported as HDT / A and / or HDT / C. HDT / A with a bending stress of 1.80 MPa corresponds to Method A, and HDT / C with a bending stress of 8.00 MPa corresponds to Method C. HDT values ​​were determined using an 80 × 10 × 4 mm ISO impact bar according to ISO 75 (2013). Determination of the action of microorganisms on plastics

[0074] Resistance to mold and bacteria was determined using plates with dimensions of 50 × 50 × 2 mm, according to Methods A and C of DIN EN ISO 846:2020. Evaluation was performed using the methods described in Annex C.

[0075] Unless otherwise specified in the table, the mechanical properties were determined using test specimens in a dry state. For this purpose, the test specimens were stored at room temperature in a dry environment for at least 48 hours after injection molding.

[0076] [Table 1]

[0077] The molding materials of Examples B1 to B8 according to the present invention exhibit good to very good resistance to mold and bacteria, and therefore show clear advantages compared to Comparative Examples B9 to B13. Example B11 has a very low concentration of the selected metal borate and does not provide sufficient resistance to mold. By comparing Examples B9 and B10 with Examples B1 to B4, it is shown that the preferably used continuous glass fiber has advantages in terms of temperature of deflection under load (HDT-C), tensile strength at break, elongation at break, and notched impact strength. On the other hand, the resistance to mold and bacteria is at the same high level as Examples B1, B2, and B4.

[0078] [Table 2]

[0079] To evaluate mold growth, a grid of 100 equally sized squares was placed on a 50 × 50 × 2 mm incubator sample plate. The number of squares showing growth was counted, excluding the 36 squares at the edges. Based on the number of squares with visible mold growth (observable with the naked eye or under a microscope), the following scores were determined. 0: None of the inner squares show any mold growth detectable under a microscope at 50x magnification. 1a: 1 to 16 squares show traces of mold growth under a microscope at 50x magnification. 2:1 to 16 squares show signs of mold growth when viewed with the naked eye. 3:17-32 squares show signs of mold growth when viewed with the naked eye. 4:33-64 squares show signs of mold growth when viewed with the naked eye.

[0080] Similar to the mold test, we evaluated incubated sample plates for bacterial resistance, and counted the squares where bacterial growth was visible to the naked eye. 0: No bacterial growth is observed in the inner square. Traces of bacterial growth can be seen in 1:1 to 16 squares.

Claims

1. A polyamide molding compound, A polymer mixture comprising: A1 55 to 85% by weight of at least one semi-crystalline aliphatic polyamide A1 selected from the group PA6, PA46, PA56, PA66, PA66 / 6, PA610, PA612, PA6 / 12, PA1010, PA11, PA12, PA1012, PA1212 and mixtures thereof, A2 15 to 45% by weight of at least one semi-aromatic polyamide selected from the group consisting of PA6I, PA5I / 5T, PA6I / 6T, PA10I / 10T, PA10T / 6T, PA6T / BACT / 66 / BAC6, PA MXD6, PA MXD6 / MXDI and mixtures thereof, 33 to 79.4 wt. % of a polymer mixture, wherein the sum of A1 and A2 is 100 wt. % of A; B 20 to 60 wt.% of reinforcing fibers; C. 0.6 to 2.0 wt. % of a metal borate salt, wherein the molar ratio of metal to boric acid ranges from 0.5 to 4; D 0 to 5.0 wt. % of an additive different from A, B, and C; 1. A polyamide molding composition comprising: a polyamide molding composition according to claim 1, wherein the total of components A to D is 100% by weight, and the molding composition does not contain any copper halide or metal phosphinate.

2. the proportion of component A is in the range of 40.4 to 74.4% by weight, preferably in the range of 46.6 to 69.25% by weight, relative to the sum of components A to D in each case, and / or the proportion of component A1 is in the range from 60 to 85% by weight, preferably in the range from 65 to 80% by weight, and the proportion of component A2 is in the range from 15 to 40% by weight, preferably in the range from 20 to 35% by weight, in each case relative to the sum of components A1 and A2, and / or the proportion of component B is in the range of 25 to 55% by weight, preferably in the range of 30 to 50% by weight, relative to the sum of components A to D in each case, and / or the proportion of component C is in the range of 0.6 to 1.6% by weight, preferably in the range of 0.7 to 1.4% by weight, relative to the sum of components A to D in each case, and / or The proportion of component D is in the range of 0 to 3.0% by weight, preferably in the range of 0.05 to 2.0% by weight.

2. The polyamide molding compound according to claim 1 .

3. the polyamide A1 is selected from PA6, PA56, PA66, PA66 / 6, PA610 and mixtures thereof, and / or The polyamide A2 is selected from PA6I / 6T, PA6T / BACT / 66 / BAC6 and mixtures thereof.

2. The polyamide molding compound according to claim 1 .

4. The component A2 is amorphous semi-aromatic polyamide PA6I / 6T containing 55 to 85 mol % of hexamethylene isophthalamide units and 15 to 45 mol % of hexamethylene terephthalamide units; and / or 2. The polyamide molding compound according to claim 1, characterized in that it is selected from semicrystalline, semiaromatic polyamides PA6T / BACT / 66 / BAC6, which contain 55 to 70 mol % of hexamethylene terephthalamide units, 20 to 25 mol % of 1,3-bis(aminomethyl)cyclohexane terephthalamide units, 6 to 16 mol % of hexamethylene adipamide units and 2 to 4 mol % of 1,3-bis(aminomethyl)cyclohexane adipamide units.

5. The reinforcing fiber B It is glass fiber, and / or selected from the group consisting of E-glass fibers, ECR-glass fibers, D-glass fibers, L-glass fibers, S-glass fibers and / or R-glass fibers; and / or It is a long glass fiber (continuous glass fiber, roving), and / or 2. Polyamide moulding material according to claim 1, characterized in that the diameter is in the range of 10 to 20 μm, preferably in the range of 12 to 17 μm.

6. The deflection temperature under load HDT-C according to ISO 75:2013 is at least 120°C, preferably at least 130°C, particularly preferably at least 200°C; and / or The deflection temperature under load HDT-A according to ISO 75:2013 is at least 200°C, preferably at least 230°C.

2. The polyamide molding compound according to claim 1 .

7. The metal borate C is sodium borate, particularly borax pentahydrate (Na ２ O2B ２ O ３ ・5H ２ O), Borax decahydrate (Na ２ O2B ２ O ３ ・10H ２ O), anhydrous borax (Na ２ O2B ２ O ３ ) and disodium octaborate tetrahydrate (Na ２ O・4B ２ O ３ ・4H ２ O), magnesium borate (2MgO.B ２ O ３ ), calcium borate (2CaO·3B ２ O ３ ・5H ２ O), calcium metaborate (CaO.B ２ O ３ ・4H ２ O), for example, hydroboracite (CaMg[B ３ O ４ (OH) ３ ] ２ ・3H ２ O), magnesium-calcium borate, barium metaborate (BaO.B ２ O ３ ・H ２ O), for example, 2ZnO.3B ２ O ３ ・7H ２ O, 2ZnO 3B ２ O ３ ・3.5H ２ O, 2ZnO 2B ２ O ３ ・3H ２ O, 4ZnO・B ２ O ３ ・H ２ O, 2ZnO 3B ２ O ３ Zinc borate (xZnO yB ２ O ３ ・zH ２ 2. The polyamide molding compound according to claim 1, wherein the borate is selected from the group consisting of calcium borate silicate, sodium borate silicate, aluminum borate silicate, aluminum borate, copper borate and iron borate.

8. 2. Polyamide moulding material according to claim 1, characterized in that the selected metal borate C is a zinc borate compound with a boric acid:metal ratio of 1 to 3, preferably 3.

9. 2. The polyamide molding compound according to claim 1, wherein component D is selected from the following group: UV stabilizers, copper halide-free heat stabilizers, radical scavengers, processing aids, inclusion inhibitors, lubricants, mold release aids, crystallization accelerators or inhibitors, flow promoters, lubricants, mold release agents, pigments, dyes and marking substances, fluorescent dyes, processing agents, antistatic agents, carbon black, graphite, carbon nanotubes.

10. 2. The polyamide molding material according to claim 1, characterized in that component D is selected from UV stabilizers, heat stabilizers, zinc oxide, zinc sulfide, zinc stearate, zinc montanate, calcium montanate, calcium stearate, aluminum stearate and mixtures thereof.

11. The molding material comprises the following components: A: A polymer mixture, A1 65 to 80% by weight of polyamides PA6, PA66, PA610 and mixtures thereof; A2 20-35% by weight of polyamide PA6I / 6T, PA6T / BACT / 66 / BAC6 and mixtures thereof, 46.6 to 69.25 wt. % of a polymer mixture, wherein the sum of A1 and A2 is 100 wt. % of A; B: 30 to 50% by weight of long glass fibers (continuous glass fibers, roving), C: 0.7-1.4 wt. % zinc borate with a boric acid:metal ratio of 0.5-4; D: 0.05 to 2.0% by weight of an additive different from A, B, and C; 2. The polyamide molding compound according to claim 1, wherein the sum of components A to D is 100% by weight, and the molding compound contains neither copper halide nor metal phosphinate.

12. Molded bodies made from the polyamide molding compound according to any one of claims 1 to 11 or having at least one region or coating made from the polyamide molding compound according to any one of claims 1 to 11, preferably produced by injection molding, extrusion or blow molding, and suitable for use in the following fields: housings, covers or frames, housings or housing components, preferably housings or housing parts of portable electronic devices, claddings or covers, household appliances, household electronics, eyeglass bases, eyeglass frames, sunglasses, cameras, binoculars, decorative articles, telecommunications devices and equipment and personal electronics, the automotive sector and other Molded bodies are interior and exterior parts for means of transport, preferably interior and exterior parts with a supporting or mechanical function in the fields of electronics, furniture, sports, mechanical engineering, facility and personal hygiene, fans (especially fan rotors or fans wheels), medicine, energy technology and driving technology, particularly preferred are molded bodies for mobile phones, smartphones, organizers, laptop computers, notebook computers, tablet computers, radios, cameras, watches, calculators, sensor housings, measuring devices, music and / or video playback devices, navigation devices, GPS devices, electronic photo frames, external hard drives and other electronic storage media.

13. Meets the requirements for disinfecting surfaces according to method A of DIN EN ISO 846:2020 and results in a classification of "zero" or "1A" or "1" when tested according to the method described in Annex C, and / or Complies with the bacterial resistance test according to method C of DIN EN ISO 846:2020, and results in a classification of "zero" or "1" when tested according to the method described in Annex C; The molded article according to claim 12 .

14. 12. Use of the polyamide molding compound according to any one of claims 1 to 11 for producing moulds that are resistant to mouldings and bacteria, in particular for producing door handles, hands-free door openers, handrails, kitchen appliances, medical devices, interior functional parts of automobiles, handles with levers and buttons, gearshift levers, control units for air conditioning systems, control units for entertainment devices, door locking systems, hinges, handles, handrails and bars in public transport, medical care beds, hospital furniture, elevator knobs and control elements, kitchen furniture, bathroom fittings and accessories, housings and covers, ventilation systems, blowers, rotors for axial fans, centrifugal fans, process fans, etc.