Steam resistant transparent polyamide

Abstract

A steam resistant transparent polyamide is provided. A polyamide molding compound, particularly preferred as a transparent molding with high steam resistance, comprises at least one copolyamide formed from at least polyamide units AB / AC / D, wherein (A) is selected as at least one cycloaliphatic diamine; (B) is selected as at least one aromatic dicarboxylic acid; (C) is selected as at least one aliphatic dicarboxylic acid; (D) is selected as at least one lactam or alpha, omega-amino carboxylic acid. Wherein the proportion of the polyamide units AB is in the range of 30 to 45 mol%, the proportion of the polyamide units AC is in the range of 30 to 40 mol%, and the proportion of the polyamide units D is in the range of 20 to 32 mol%, and wherein the sum of the polyamide units AB, the polyamide units AC and the polyamide units D is 100 mol%.

Description

Technical Field

[0001] This invention relates to transparent polyamides based on alicyclic diamine and aromatic dicarboxylic acid structural units, which possess exceptional vapor resistance and good mechanical properties. The invention also relates to methods for preparing such transparent polyamides, uses of such polyamides, and components made from such polyamides. Background Technology

[0002] Transparent amorphous copolyamide molding compounds and transparent amorphous polyamide molding articles that can be produced from them are known from the prior art. In the field of transparent polyamides, a distinction is made in principle between two polymer types: microcrystalline transparent polyamides and amorphous transparent polyamides.

[0003] For example, microcrystalline transparent copolyamide molding compounds and their uses in eyeglass frames, observation glass and covers, and lampshades are known from DE-A-43 10 970. The polyamide described in that document is prepared from 4,4'-diaminocyclohexylmethane as a diamine component and dodecanoic acid as an acid component.

[0004] EP-A-1 595 907 describes a transparent amorphous polyamide based on alicyclic diamines and C14 dicarboxylic acids.

[0005] EP-A-0 725 101 also discloses a transparent amorphous polyamide based on alicyclic diamines and C12 dicarboxylic acids that exhibits excellent stress cracking resistance, especially in most solvents.

[0006] Such transparent systems based on alicyclic diamines can also contain aromatic structural units. For example, EP-A-725100 discloses a MACMI / 12 type transparent system, DE-C-2642244, WO-A-2007 / 087896, and EP-A-2 666 803 disclose MACMI / MACMT / 12 type transparent systems, and EP-A-055 335 discloses a PACMI / PACMT / 12 type transparent system. US-2009 / 306308 discloses PACMT / PACM10 / 12 type transparent systems or PACMT / PACM14 / 12 type transparent systems and PACMT / MACM14 / 12 type transparent systems, each with high aliphatic content and unsatisfactory thermomechanical properties. US 5,416,172 discloses a MACMI / MACMT / MACM6 / 12 type transparent system.

[0007] EP-A-0603813 describes a molded article made of a transparent copolyamide and the transparent copolyamide itself, which is formed from long-chain monomers having 9 to 12 carbon atoms and from monomers for semi-aromatic polyamides in a random distribution, and which has the characteristics of rigidity, strength, high toughness and excellent solvent stability even under restricted conditions. Summary of the Invention

[0008] According to the formulation, the transparent polyamide mentioned in the introduction possesses good mechanical properties and good transparency. However, it has been found that transparent polyamide systems known from the prior art exhibit unsatisfactory resistance to repeated vapor exposure. In particular, it has been found that known systems often form capillary cracks under these conditions, and therefore, when such materials are used to enclose spaces between each other, they lose both their transparency and undergo mechanical property impairment, and may also lose their sealing properties.

[0009] Therefore, the object of the present invention is particularly to provide transparent polyamide molding compounds that are improved compared to the prior art, especially transparent molding compounds based on alicyclic diamines and aromatic dicarboxylic acids and other aliphatic structural units, and which exhibit high vapor resistance. Furthermore, the components are scratch-resistant and virtually non-absorbent, and they possess high chemical stability, which also means that, for example, when exposed to foods or chemicals containing dyes, they can be easily cleaned without leaving stains.

[0010] Therefore, the present invention provides the following polyamide molding compound, as well as the use of such polyamide molding compound, a method for preparing such polyamide molding compound, and molded articles produced from said molding compound.

[0011] Specifically, the present invention relates to polyamide molding compounds comprising at least one copolyamide. This copolyamide is formed from at least the polyamide units AB / AC / D as defined below. While other polyamide units may also be present in this copolyamide, it is preferred that only these polyamide units are present. In particular, complex structures can be formed when, for example, two different systems are selected for (A) as defined below.

[0012] For example, if two different systems A' and A'' are chosen for (A), then the polyamide can then be abbreviated as A'B / A''C / D, although upon closer examination, this is a system with the following polyamide units: A'B / A'C / A''B / A''C / D.

[0013] The structural unit of a copolyamide formed at least by polyamide units AB / AC / D is defined as follows:

[0014] (A) is selected as at least one alicyclic diamine from the group consisting of: bis(4-amino-3-methylcyclohexyl)methane (MACM) and bis(4-aminocyclohexyl)methane (PACM).

[0015] (B) Select at least one aromatic dicarboxylic acid from the group consisting of isophthalic acid (I), naphthalic acid and terephthalic acid (T).

[0016] (C) Select at least one aliphatic dicarboxylic acid from the group consisting of: sebacate, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, and hexadecanoic acid.

[0017] (D) Select at least one lactam or at least one from the following groups. : laurolactam (LC 12), undecanolactam (LC 11), 12-aminododecanoic acid, and 11-aminoundecanoic acid.

[0018] The following rules apply here:

[0019] The proportion of polyamide units AB ranges from 30 mol% to 45 mol%.

[0020] The proportion of polyamide units AC ranges from 30 mol% to 40 mol%, and

[0021] The proportion of polyamide unit D ranges from 20 mol% to 32 mol%.

[0022] The total amount of polyamide units AB, AC and D is 100 mol.

[0023] It was found that the polyamide molding compound made from this copolyamide can overcome the disadvantages of transparent molding compounds known from the prior art, and can provide good thermomechanical properties and good transparency, and is particularly stable with respect to frequent contact with steam at a temperature of 100°C, i.e., only a small amount of fogging occurs even if it occurs, and / or only a few capillary cracks form even if it occurs.

[0024] Therefore, such molded products are not only suitable for kitchen areas and dishwashers, but also for food processing machines that use steam treatment.

[0025] Specifically, these properties can only be achieved under the following precise conditions: long-chain aliphatic dicarboxylic acids as, in addition to, long-chain lactams or The structural units other than those mentioned above are combined with at least one alicyclic diamine and at least one aromatic dicarboxylic acid. These properties cannot be achieved if one of these structural units is omitted. Furthermore, as will be demonstrated below based on exemplary embodiments, these properties also cannot be achieved if the components are not used in the claimed proportions.

[0026] The sheet produced from the transparent molding compound and having a thickness of 2 mm has a transparency of more than 90%, particularly more than 92%, as measured by ASTM D1003, and a haze of at most 5%, particularly more than 3%. For the desired use of the molding compound according to the invention, rigidity (tensile modulus of elasticity greater than 1500 MPa) and high toughness (preferably impact resistance at 23°C and -30°C: no breakage) are achieved.

[0027] In the context of this application, the value of transmittance, used as a measure of transparency, is always understood to be determined according to the ASTM D1003:2013 (CIE-C Light Source) method. In the experiments conducted below, transmittance measurements were performed on a 70×2 mm disk or a 60×60×2 mm plate using a BYK Gardner Haze Guard Plus instrument (DE). Transmittance is given for the visible light wavelength range as defined by CIE-C, i.e., significant intensity between approximately 400 nm and 770 nm. For this purpose, 70×2 mm disks or 60×60×2 mm square plates are produced, for example, in polished molds on an Arburg injection molding machine, with a barrel temperature of 200°C to 340°C and a mold temperature of 20°C to 140°C.

[0028] According to another preferred embodiment, the glass transition temperature (Tg) of the copolyamide is 150°C to 200°C, particularly preferably 160°C to 180°C.

[0029] The first preferred embodiment of the polyamide molding compound is characterized in that the sum of aliphatic polyamide units AC and D is in the range of 55 mol% to 65 mol%, preferably in the range of 58 mol% to 64 mol%. It has been found that specifically selecting aliphatic units within this range particularly increases steam resistance at high temperatures. Preferably, the proportion of polyamide units AB is in the range of 35 mol% to 45 mol%, more preferably in the range of 36 mol% to 42 mol%.

[0030] More preferably, the proportion of polyamide units AC is in the range of 31 mol% to 38 mol%, more preferably in the range of 32 mol% to 35 mol%.

[0031] According to another preferred embodiment, the proportion of polyamide unit D is in the range of 22 mol% to 31 mol%, preferably in the range of 25 mol% to 30 mol%.

[0032] When the copolyamide AB / AC / D is amorphous and (A) is selected only as bis(4-amino-3-methylcyclohexyl)methane (MACM), particularly good properties of the polyamide molding compound are obtained. In the context of this invention, amorphous means that the enthalpy of melting of the copolyamide, as determined according to ISO 11357-3 (2012), is less than or equal to 3 J / g.

[0033] (B) Preferably, it is selected as a mixture of isophthalic acid (I) and terephthalic acid (T). The ratio of isophthalic acid (I) to terephthalic acid (T) is preferably in the range of 40:60 to 60:40, and particularly preferably in the range of 45:55 to 55:45. The two structural units are usually used in a ratio of approximately 1:1.

[0034] As mentioned, the use of long-chain dicarboxylic acids is important for achieving the desired effect. Particularly good properties can be obtained when (C) is selected only from dodecanoic acid.

[0035] Further preferably, (C) is selected only from dodecanoic acid and (D) is selected only from laurolactam (LC12).

[0036] When the copolyamide consists only of polyamide units AB / AC / D, particularly stable properties can be obtained. As mentioned above, it should be considered here that this is understood as a simplified form, and if, for example, two different alicyclic diamines are used for (A), the structure A'B / A''C / D, which exists only as a simplified form, also includes systems that actually exist as the following polyamide units: A'B / A'C / A''B / A''C / D.

[0037] A particularly preferred embodiment of the polyamide molding compound has the following structure: MACMT / MACMI / MACM12 / 12, i.e., formed solely of MACM, terephthalic acid, isophthalic acid, dodecanoic acid, and laurolactam. In this case, the polyamide units are preferably distributed as follows, in molar percentages and totaling 100%:

[0038] MACMT / MACMI / MACM12 / 12: 17% to 22% / 17% to 22% / 31% to 36% / 24% to 31%.

[0039] For many applications, such polyamide molding compounds can be further mixed with additives required for property modification, and are typically further mixed with additives required for property modification. Therefore, the polyamide molding compounds according to the invention can contain conventional additives in typically low proportions (e.g., less than 15% by weight, preferably less than 10% by weight, particularly preferably less than 0.1% to 5.0% by weight).

[0040] Therefore, in another preferred embodiment, the present invention relates to a polyamide molding compound comprising:

[0041] 85% to 100% by weight, preferably 90% to 100% by weight, particularly preferably 95.0% to 99.9% by weight of the copolyamide at least formed of polyamide units AB / AC / D as described above; 0% to 15% by weight, preferably 0% to 10% by weight, particularly preferably 0.1% to 5.0% by weight of additives, said additives preferably selected from the group consisting of: polyamides different from the copolyamide AB / AC / D according to the invention; UV stabilizers; heat stabilizers; free radical scavengers; processing aids; inclusion inhibitors; lubricants; Release agents, including metal stearates or metal montanates, wherein the metal is preferably selected from magnesium, calcium, or barium; mineral oils or fatty acid amides; defoamers; plasticizers; functional additives that affect optical properties, especially refractive index; impact modifiers; fillers and / or admixtures; optical brighteners; dyes; or mixtures thereof, wherein the fillers and / or admixtures are preferably nanoscale and / or selected from the group consisting of: glass fibers, glass beads, carbon fibers, carbon black, graphite, flame retardants, including minerals such as titanium dioxide, calcium carbonate, or barium sulfate, or mixtures thereof.

[0042] Preferred polyamides, different from the copolyamides AB / AC / D according to the present invention, are PA11, PA12, PA610, PA612, PA614, PA616, PA1010, PA1012, PA1014 and PA1016, with particular preference given to PA12.

[0043] Preferred impact modifiers are selected from the group consisting of acid-modified or anhydride-modified ethylene-α-olefin copolymers, ethylene-glycidyl-methacrylic acid copolymers, and methacrylate-butadiene-styrene copolymers.

[0044] Therefore, fillers or reinforcing agents can also be added to the molding compound according to the invention. In this case, the molded articles produced by the molding compound are not necessarily transparent in nature. Reinforcing agents that can be used with glass fibers and carbon fibers are particularly those based on renewable raw materials and those with a bioenergy content of more than 50%. Natural fibers, such as cellulose fibers, hemp fibers, flax fibers, cotton fibers, wool fibers, or wood fibers, are particularly preferred.

[0045] However, preferably, such polyamide molding compounds do not contain any additives in the form of fillers and / or admixtures in the form of granules and / or fibers.

[0046] The present invention further relates to a method for preparing the polyamide molding compound as described above, wherein the method is preferably characterized by preparing a copolyamide at least formed of polyamide units AB / AC / D in a pressure vessel, wherein the pressure stage is at 270°C to 330°C, and the subsequent expansion is at 260°C to 320°C, and the subsequent degassing is at 260°C to 320°C, and the polyamide molding compound is discharged in the form of strands, cooled, granulated and dried, optionally mixed with additives as granulating material and formed in an extruder at a melt temperature of 250°C to 350°C to form strands, and shredded using a suitable granulator to obtain pellets.

[0047] Preferably, the solution viscosity of the copolyamide according to the invention, as determined according to ISO 307 (2013), is that of a solution of 0.5 g of polymer in 100 ml of m-cresol at 20°C. The value is 1.5 to 2.5, particularly preferably 1.6 to 2.0, and very particularly preferably 1.65 to 1.85.

[0048] To set the desired relative viscosity, measured at 20°C in a solution of 0.5 g of polymer in 100 ml of m-cresol, a diamine or dicarboxylic acid can be used in a slight excess of 0.01 mol% to 3 mol%. The conditioning process preferably uses 0.01 wt% to 2.0 wt%, more preferably 0.05 wt% to 0.5 wt% of a monoamine or monocarboxylic acid. Suitable conditioners are benzoic acid, acetic acid, propionic acid, stearylamine, or mixtures thereof. Conditioners containing amine or carboxylic acid groups and additionally containing HALS-type or tert-butylphenol-type stabilizer groups are particularly preferred, such as triacetone diamine derivatives or isophthalic acid-ditriacetone diamine derivatives. A combination of excess diamine and monocarboxylic acid is particularly preferred for viscosity conditioning.

[0049] Suitable catalysts for accelerating the polycondensation reaction are phosphorus-containing acids (e.g., H3PO2, H3PO3, H3PO4), their salts, or organic derivatives, which simultaneously reduce discoloration during processing. The amount of catalyst added ranges from 0.01 wt% to 0.5 wt%, preferably from 0.03 wt% to 0.1 wt%. Suitable defoamers for preventing foaming during the degassing process are aqueous emulsions, for a 10% emulsion containing 0.001 wt% to 1.0 wt%, preferably from 0.01 wt% to 0.10 wt%, of organosilicon or organosilicon derivatives.

[0050] Prior to the polycondensation process, a suitable heat stabilizer or suitable UV stabilizer may be added to the mixture in an amount of 0.01% to 0.5% by weight. A high melting point stabilizer is preferred. Irganox 1098 is particularly preferred.

[0051] The present invention further relates to molded articles made of such polyamide molding compounds. In particular, the present invention relates to steam-resistant, transparent molded articles made of or having at least one region made of polyamide molding compounds as described above, preferably produced by injection molding and / or injection-compression molding at a melt temperature of 230°C to 320°C, wherein the mold is adjusted to a temperature of 40°C to 130°C and wherein, optionally, compression is applied under the mold at a temperature of 40°C to 130°C after filling the cavity for thermoforming.

[0052] The expansion-injection-compression molding method is a particularly suitable method for producing molded articles with defect-free, low-stress surfaces (e.g., lenses for eyeglasses or high-priced housing components) made of transparent polyamide molding compound according to the invention, wherein a processing cavity with a wall thickness of 1 mm to 5 mm is filled, and then the mold cavity is expanded to a greater wall thickness while continuing to fill.

[0053] Suitable methods for producing films, tubes, and semi-finished products of single-layer or multi-layer designs from the transparent polyamide molding compound according to the invention include an extrusion process using a melt temperature between 250°C and 350°C on a single-screw or multi-screw extruder, wherein, depending on the compatibility of the different layers, a suitable adhesion promoter in the form of an appropriate copolymer or blend may be used.

[0054] The molded article can then be dyed or colored as a whole using a process known as immersion bath. Optional machining of the molded article includes milling, drilling, grinding, laser marking, laser cutting, and / or laser welding.

[0055] Such molded articles are particularly preferably characterized by their resistance to more than 700, preferably more than 1,000, steam cycles.

[0056] Such molded articles can preferably be pipes or containers, preferably pipes or containers that come into contact with water and / or steam. Particularly preferred are pipes or containers used in processing technologies (including heating technologies) and food technologies, especially containers used in the production and / or processing and / or heating of foods in the field of infant and / or toddler foods.

[0057] Such molded articles are preferably characterized by light transmittance, which is measured according to ASTM D1003 (2013) using a Haze Gard Plus measuring instrument from Byk Gardner with CIE light source C at a temperature of 23°C on a plate with dimensions of 2×60×60 mm or on a disk with dimensions of 2×70 mm, and the light transmittance is at least 88%, preferably at least 90%, and particularly preferably at least 92%.

[0058] Finally, the invention also relates to the use of such molded articles as components of household appliances (especially food containers or components thereof), particularly as components of kitchen appliances, especially for the production and / or processing and / or heating of food using steam.

[0059] Other implementation schemes are described in this article. Attached Figure Description

[0060] Preferred embodiments of the invention are described below with reference to the accompanying drawings, which are for illustrative purposes only and should not be construed as restrictive. In the drawings:

[0061] Figure 1 A molded article used to determine steam resistance is shown.

[0062] Figure 2 The apparatus used to determine steam resistance is shown.

[0063] List of reference numerals

[0064] Detailed Implementation

[0065] Preferred embodiments of the invention are described below based on exemplary embodiments, which are for illustrative purposes only and should not be construed as limiting.

[0066] The transparent copolyamide according to the invention is prepared in a known stirred pressure autoclave having a storage container and a reaction vessel in a manner known per se:

[0067] The storage container was initially filled with deionized water (based on 25% by weight of the mixture in Table 1) and monomers and additives were added. It was then repeatedly inerted with nitrogen. The mixture was heated to 180°C to 230°C while being stirred under pressure established to obtain a homogeneous solution. This solution was pumped through a sieve into a reaction vessel, where it was heated to the desired reaction temperature of 260°C to 350°C under a pressure not exceeding 30 bar. The mixture was maintained at this reaction temperature for 2 to 4 hours during the pressure phase. In the subsequent expansion phase, the pressure was reduced to atmospheric pressure over 1 to 2 hours, during which time the temperature may drop slightly.

[0068] In the subsequent degassing stage, the mixture is held at atmospheric pressure at a temperature of 270°C to 350°C for 0.5 to 1 hour. The polymer melt is discharged in strands, cooled in a water bath at 15°C to 80°C, and granulated. The granulated material is dried under nitrogen or reduced pressure at 80°C to 120°C for 12 hours until the moisture content is less than 0.1% by weight.

[0069] The following monomers were used to prepare the copolyamides described in the examples and comparative examples.

[0070] 3,3'-Dimethyl-4,4'-Diaminodicyclohexylmethane (MACM): Solidification range according to ASTM D1015-55: -7°C to -0.6°C; Manufacturer: BASF AG, Germany.

[0071] Dodecanoic acid (DDS): Melting range: 128°C to 132°C; Manufacturer: Invista Nederland BV, Netherlands.

[0072] Isophthalic acid (IPS): Melting range: 345°C to 348°C; Manufacturer: Flint Hills Resources, Switzerland.

[0073] Terephthalic acid (TPS): Melting range: >400℃; Manufacturer: BP Amoco Chemical Company, USA.

[0074] Laurolactam (LL): Melting range: 149°C to 153°C; Manufacturer: EMS-CHEMIE AG, Switzerland.

[0075] In addition, approximately 0.15% by weight of benzoic acid was used as a chain regulator, and approximately 0.01% by weight of Antifoam RD was used as an antifoaming agent (10% by weight emulsion, Dow Corning SA, Belgium), with concentrations based on the mixtures in Table 1 in each case.

[0076] The following standards were applied to the following test specimens for measurement.

[0077] Tensile modulus of elasticity:

[0078] ISO 527 (2012), where the traction speed is 1 mm / min; ISO tensile specimen, standard: ISO / CD 3167, type A1, 170×20 / 10×4 mm; temperature 23℃.

[0079] Breaking strength and elongation at break:

[0080] ISO 527 (2012), where the traction speed is 50 mm / min; ISO tensile specimen, standard: ISO / CD 3167, type A1, 170×20 / 10×4 mm; temperature 23℃.

[0081] Xia's incision impact resistance:

[0082] ISO test specimen, standard: ISO / CD 3167, type B1, 80×10×4 mm; temperature 23℃.

[0083] Glass transition temperature (Tg), melting point, and heat of fusion:

[0084] ISO Standards 11357-1, 11357-2, 11357-3 (2013); Granular Materials; Differential Scanning Calorimetry (DSC) was performed using a DSC 2920 instrument from TA Instruments at a heating rate of 20 K / min and a cooling rate of 5 K / min. Thermographs were analyzed using Universal Analysis 2000 from TA Instruments. For the purpose of determining the glass transition temperature, the samples were quenched in dry ice after the first heating run. The glass transition temperature (Tg) was determined during the second heating run. The midpoint of the glass transition range reported as the glass transition temperature (Tg) was determined using the "half-height" method.

[0085] transparency:

[0086] ASTM D 1003 (2013); 70 mm disk or 60×60 mm plate, 2 mm thick, temperature 23°C; Haze Gard plus measuring instrument from Byk Gardner using CIE light source C. Transmittance values ​​are reported as a percentage of incident light.

[0087] Relative viscosity:

[0088] ISO 307 (2007); 0.5 g in 100 ml m-cresol solvent; temperature 20°C; relative viscosity (RV) calculated according to RV=t / t0 according to section 11 of the standard.

[0089] HDT A (1.8 MPa) and HDT B (0.45 MPa):

[0090] ISO 75; ISO impact test specimen, 80×10×4.

[0091] Steam resistance (ability to withstand steam circulation):

[0092] Molded part 1 (a tubular part with a flange at one end) (see Figure 1 The molded part ( ) is produced by injection molding from the described material and has the following dimensions: tube length L1 = 100 mm, tube inner diameter D1 = 20 mm, wall thickness W of tube and flange = 2 mm, flange diameter F1 = 100 mm, and radius between tube and flange = 5 mm. For this test, four molded parts are placed from above into apparatus 2 (see [reference]) for determining steam resistance. Figure 2 The opening 2-1 is such that pipe 1-1 protrudes into the interior of the device, and flange 1-2 is centrally supported on the outside relative to opening 2-1 (opening diameter D2 = 50 mm). To maintain this position of the molded part during testing, a guide element is installed on the upper side of the testing device. One steam inlet pipe 2-2 protrudes from below into the device for each molded part and is vertically positioned 5 cm below the molded part at the center. The steam supply is controlled by a valve. The external dimensions of device 2 used to determine steam resistance are 60 × 20 × 15 (L2 × H × T) cm.

[0093] During the first part of the test (steam treatment), the molded part was exposed to a steam stream at 100°C for 75 minutes. Under these conditions, the steam flow rate from the steam supply pipe was 0.3 g / min. Condensed steam could exit through openings 2-3 in the lower part of the test apparatus, while uncondensed steam could escape through openings in the molded part.

[0094] After steam treatment for 75 minutes, the steam supply was stopped, and the molded part was allowed to cool for another 75 minutes. The ambient temperature was 23°C and the relative humidity was 60%.

[0095] After the cooling phase ends, a new cycle begins again while the molded parts are exposed to steam.

[0096] During testing, the molded part is visually evaluated for capillary crack formation. Capillary cracks form particularly on the pipe near the steam supply pipe and in the area transitioning to the flange. The table lists the corresponding number of test cycles for the first observation of capillary cracks on the molded part. If no capillary cracks are observed on the molded part even after 1001 cycles, the test is terminated.

[0097] Test specimens were produced on an Allrounder 420 C 1000-250 injection molding machine from Arburg. A barrel temperature of 230°C to 320°C was used. The mold temperature was 80°C. Polished molds were used for the plates used for transmittance measurement and for the molded parts used to determine steam resistance.

[0098] Table 1 below compares the embodiments (E1 and E2) according to the present invention with comparative examples (CE1 to CE4).

[0099] Table 1:

[0100]

[0101]

[0102] As can be seen from the examples and comparative examples, the polyamide molding compounds according to the present invention alone can achieve a good combination of (thermo)mechanical properties (particularly good values ​​for HDT, modulus of elasticity, elongation at break, and notch impact resistance) and good resistance to steam cycling. Specifically, a comparison with CE1 shows that dodecanoic acid (or a corresponding long-chain diacid as claimed) is crucial as a structural unit, and a comparison with CE2 shows that laurolactam (or a corresponding long-chain lactam as claimed) is crucial as a structural unit. Without these structural units, the properties of the present invention cannot be achieved. Furthermore, a comparison with CE3 and CE4 shows that the specific setting of the proportions is crucial. For example (compared to CE3), molding compounds using too little dodecanoic acid and too much aromatic dicarboxylic acid cannot ensure resistance to steam cycling. Furthermore, a comparison with CE4 shows that an excessively high proportion of aliphatic blocks also does not exhibit sufficient resistance to steam cycling.

[0103] Therefore, compared to the comparative examples, the embodiments demonstrate that a single polyamide unit or structural unit is crucial to ensuring important properties, and that, in order to provide important properties equally effectively, the proportion is only allowed within the narrow range claimed.

Claims

1. A polyamide molding compound comprising at least one copolyamide formed from polyamide units AB / AC / D, wherein (A) Select only bis(4-amino-3-methylcyclohexyl)methane (MACM); (B) Select at least one aromatic dicarboxylic acid from the group consisting of isophthalic acid (I), naphthalic acid, and terephthalic acid (T); (C) Selected only from dodecanoic acid; (D) Select at least one lactam or at least one from the following groups. -Aminocarboxylic acids: laurolactam (LC12), undecanolactam (LC11), 12-aminododecanoic acid, and 11-aminoundecanoic acid, in The proportion of polyamide units AB ranges from 30 mol% to 45 mol%. The proportion of polyamide units AC ranges from 30 mol% to 40 mol%, and The proportion of polyamide unit D ranges from 20 mol% to 32 mol%. as well as The total amount of polyamide units AB, AC and D is 100 mol.

2. The polyamide molding compound according to claim 1, characterized in that... The sum of aliphatic polyamide units AC and D is in the range of 55 mol% to 65 mol%, and the proportion of said polyamide unit AB is in the range of 35 mol% to 45 mol%.

3. The polyamide molding compound according to claim 1, characterized in that... The sum of aliphatic polyamide units AC and D ranges from 58 mol% to 64 mol%, and the proportion of said polyamide unit AB ranges from 36 mol% to 42 mol%.

4. The polyamide molding compound according to any one of claims 1 to 3, characterized in that... The proportion of the polyamide unit AC is in the range of 31 mol% to 38 mol%. And / or the proportion of the polyamide unit D is in the range of 22 mol% to 31 mol%.

5. The polyamide molding compound according to any one of claims 1 to 3, characterized in that... The proportion of the polyamide unit AC is in the range of 32 mol% to 35 mol%. And / or the proportion of the polyamide unit D is in the range of 25 mol% to 30 mol%.

6. The polyamide molding compound according to claim 1, characterized in that... (B) The choice is a mixture of isophthalic acid (I) and terephthalic acid (T).

7. The polyamide molding compound according to claim 1, characterized in that... (B) Select a mixture of isophthalic acid (I) and terephthalic acid (T), wherein the ratio of isophthalic acid (I) to terephthalic acid (T) is in the range of 40:60 to 60:

40.

8. The polyamide molding compound according to claim 1, characterized in that... (B) The mixture of isophthalic acid (I) and terephthalic acid (T) is selected, wherein the ratio of isophthalic acid (I) to terephthalic acid (T) is in the range of 45:55 to 55:

45.

9. The polyamide molding compound according to claim 1, characterized in that... (D) Selected only from laurolactam (LC 12).

10. The polyamide molding compound according to claim 1, characterized in that... The copolyamide is composed solely of the polyamide units AB / AC / D.

11. The polyamide molding compound according to claim 1, characterized in that... The polyamide molding compound is composed of the following: 85% to 100% by weight of a copolyamide formed at least from the polyamide units AB / AC / D; 0% to 15% by weight of additives.

12. The polyamide molding compound according to claim 1, characterized in that... The polyamide molding compound is composed of the following: 90% to 100% by weight of a copolyamide formed at least from the polyamide units AB / AC / D; 0% to 10% by weight of additives.

13. The polyamide molding compound according to claim 1, characterized in that... The polyamide molding compound is composed of the following: 95.0% to 99.9% by weight of a copolyamide formed at least from the polyamide units AB / AC / D; 0.1% to 5.0% by weight of additives.

14. The polyamide molding compound according to any one of claims 11 to 13, characterized in that... The additives are selected from the group consisting of: polyamides other than copolyamides AB / AC / D; UV stabilizers; heat stabilizers; free radical scavengers; processing aids; inclusion inhibitors; lubricants; release agents, including metal stearates or metal lignites; mineral oils or fatty acid amides; defoamers; plasticizers; functional additives that affect optical properties, including refractive index; impact modifiers; fillers and / or admixtures; optical brighteners; dyes; or mixtures thereof.

15. The polyamide molding compound according to claim 14, characterized in that... The additive is selected from mold release agents, including metal stearates or metal lignite, wherein the metal is selected from magnesium, calcium, and barium.

16. The polyamide molding compound according to claim 14, wherein the filler and / or the admixture is nanoscale and / or selected from the group consisting of: glass fiber, glass beads, carbon fiber, carbon black, graphite, flame retardant, minerals including titanium dioxide, calcium carbonate or barium sulfate, or mixtures thereof.

17. The polyamide molding compound according to claim 11, characterized in that... The additive does not contain any particulate and / or fibrous fillers and / or admixtures.

18. A method for preparing a polyamide molding compound according to any one of claims 1 to 17, characterized in that... The copolyamide, at least formed from the polyamide units AB / AC / D, is prepared in a pressure vessel, wherein the pressure stage is at 180°C to 330°C, the subsequent expansion is at 260°C to 350°C, and the subsequent degassing is at 270°C to 350°C. The polyamide molding compound is discharged in strand form, cooled, granulated, and the granulated material is dried, optionally mixed with additives as a granulating material, and formed in an extruder at a melt temperature of 250°C to 350°C to form strands. The strands are then shredded using a suitable granulator to obtain pellets.

19. The method according to claim 18, characterized in that... The copolyamide, at least formed of the polyamide units AB / AC / D, is prepared in a pressure vessel, wherein the pressure stage is at 270°C to 330°C, the subsequent expansion is at 260°C to 320°C, and the subsequent degassing is at 260°C to 320°C.

20. A molding article made of a polyamide molding compound according to any one of claims 1 to 17 or having at least one region made of a polyamide molding compound according to any one of claims 1 to 17.

21. The molded article of claim 20, wherein the molded article is produced by injection molding and / or injection-compression molding at a melt temperature of 230°C to 320°C, wherein the mold is adjusted to a temperature of 40°C to 130°C, and wherein optionally, compression is applied to the mold at a temperature of 40°C to 130°C for thermoforming after filling the cavity.

22. The molding article according to claim 20, wherein the molding article is a steam-resistant, transparent molding article.

23. The molded article according to claim 20, characterized in that... The molded article has the ability to withstand more than 700 steam cycles.

24. The molded article according to claim 20, characterized in that... The molded part has the resistance to more than 1,000 steam cycles.

25. The molded article according to any one of claims 20 or 23, characterized in that... The molded product is a pipe or container.

26. The molded article according to any one of claims 20 or 23, characterized in that... The molded part is a pipe or container for contact with water and / or steam.

27. The molded article according to any one of claims 20 or 23, characterized in that... The molded articles are pipes or containers in processing technology and food technology, including containers used in the production and / or processing and / or heating of food in the field of infant and / or toddler food.

28. Use of the molded article according to any one of claims 20 to 25 as a food container or a component thereof.

29. The use according to claim 28, wherein the use is as a component of a kitchen appliance.

30. The use according to claim 28, wherein the use is for producing and / or processing and / or heating food using steam.

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