Polyamide composition

Abstract

A composition comprising: at least 50% by weight of a polyamide component; the polyamide component consists of: a) 50 to 95 parts by weight of at least one alicyclic polyamide based on an alicyclic diamine having 10 to 20 carbon atoms and an aliphatic dicarboxylic acid having 8 to 18 carbon atoms; and b) 50 to 5 parts by weight of at least one linear aliphatic polyamide having on average 9 to 12 C atoms in monomer units, wherein the sum of the parts by weight of a) and b) is 100.

Description

Technical Field

[0001] This invention relates to a homogeneous amorphous composition based on alicyclic polyamides with improved thermoforming properties. Background Technology

[0002] Polymer blending is a known method for modifying properties. However, appropriate blending can produce specific synergistic effects that can be used to achieve surprising improvements beyond standard materials. Polyamide blending is known in the prior art, and a large body of literature can be found on this topic.

[0003] US2018327592A1 describes a composition with improved dimensional stability due to reduced water absorption, comprising an amorphous polyamide or a mixture of amorphous polyamides, and a semi-crystalline polyamide or a mixture of semi-crystalline polyamides having an average number of carbon atoms relative to nitrogen atoms greater than or equal to 8, wherein the average number of carbon atoms relative to nitrogen atoms in each semi-crystalline polyamide is greater than or equal to 8. It is mentioned that when the amorphous polyamide is PAMACM.12, the semi-crystalline polyamide is not PA 12.

[0004] US20230033437A1 relates to black-colored polyamide molding compounds based on transparent polyamides with good weather resistance. These PA molding compounds have numerous industrial applications for the manufacture of articles selected from: interior and exterior parts for automobiles, motorcycles, camping vehicles or RVs; building and facade components; decorative structural frames; operating knobs or joysticks; covers; visible surfaces; backlight assemblies; mobile phone screens; tablet computers; electronic device housings; vehicle interior parts; household appliances; containers; vehicle keys; and leisure and outdoor products.

[0005] US11466153B2 discloses a polyamide molding compound based on a mixture of a specific amorphous or microcrystalline polyamide and a specific partially crystalline polyamide, characterized by very good stress cracking resistance and simultaneously very good optical properties, particularly high light transmittance and low haze. Furthermore, it has been demonstrated that blends of amorphous polyamide with commonly used partially crystalline polyamide 12 produce inferior properties in comparison.

[0006] US2018 / 0100064A1 relates to polyamide molding compounds reinforced with glass fillers and exhibiting low haze. These polyamide molding compounds are based on amorphous copolyamides, and the polyamide molding compound contains exactly one amorphous copolyamide. Adding partially crystalline polyamide is practically possible but not mandatory to achieve the desired optical properties.

[0007] US9416233B2 discloses composite polyamide fine particles comprising a polyamide (A1) with a melting point or glass transition temperature above 100°C and a polymer (A2) different from the polyamide (A1), wherein the composite polyamide fine particles have a dispersed structure in which multiple domains, each with a particle size of 0.05 to 100 µm and predominantly composed of the polymer (A2), are dispersed in a matrix in which polyamide (A1) is the predominant component. The composite polyamide fine particles exhibit a significant improvement in fracture toughness.

[0008] EP2857437A1 describes a polyamide mixture comprising at most 50% by weight of a polyamide component, said polyamide component consisting of a) 50 to 95 parts by weight of microcrystalline PA PACMX (where X = 8 to 18) and b) 50 to 5 parts by weight of a semi-crystalline linear aliphatic polyamide having an average of 8 to 12 carbon atoms in the monomer unit. The sum of the parts by weight is 100.

[0009] However, existing technical literature does not explicitly disclose methods for improving the thermoformability of homogeneous amorphous compositions based on alicyclic polyamides. Therefore, there is a need to develop novel polyamide compositions based on alicyclic polyamides with improved thermoformability. Summary of the Invention

[0010] For this purpose, according to one object, the present invention relates to the use of at least one linear aliphatic polyamide having an average of 9 to 12 C atoms in a monomer unit for improving the thermoformability of a homogeneous amorphous composition comprising at least one alicyclic polyamide based on an alicyclic diamine having 10-20 carbon atoms and an alicyclic dicarboxylic acid having 8-18 carbon atoms.

[0011] This invention is based on the discovery that introducing at least one linear aliphatic polyamide into a homogeneous amorphous composition based on alicyclic polyamides enables the material to be thermoformed at lower temperatures than currently commercially available materials. Simultaneously, post-thermoforming relaxation is hindered, allowing the thermoformed material to maintain its shape for a longer period.

[0012] In the context of this invention, a homogeneous amorphous composition refers to an amorphous composition having only one glass transition temperature (with or without a melting temperature) after the introduction of at least one linear aliphatic polyamide into an alicyclic polyamide. Preferably, the enthalpy of crystallization during a cooling step at a rate of 20°C / min in differential scanning calorimetry (DSC) is less than 15 J / g, particularly less than 5 J / g, as measured according to standard ISO 11357.

[0013] Preferably, in this use, the composition comprises: At least 50% by weight of polyamide component; The polyamide component consists of the following: a) 50 to 95 parts by weight of at least one alicyclic polyamide based on an alicyclic diamine having 10-20 carbon atoms and an alicyclic dicarboxylic acid having 8-18 carbon atoms; and b) 50 to 5 parts by weight of at least one linear aliphatic polyamide having an average of 9 to 12 carbon atoms in the monomer unit. The sum of the weight parts of a) and b) is 100.

[0014] More preferably, in this application, the polyamide component a) comprises 60 to 95% by weight relative to the total weight of the polyamide component, and the polyamide component b) comprises 5 to 40% by weight.

[0015] Particularly preferably, in this application, the polyamide component a) comprises 75 to 90% by weight relative to the total weight of the polyamide component, and the polyamide component b) comprises 10 to 25% by weight.

[0016] Other advantages of the present invention will be apparent to those skilled in the art upon reading the specification. Invention Details According to the present invention, a first embodiment provides a homogeneous amorphous composition comprising, based on the total weight of the composition, at least 50% by weight, preferably at least 60% by weight, particularly preferably at least 70% by weight, more preferably at least 80% by weight, and very particularly preferably at least 90% by weight, or at least 95% by weight, a polyamide component, said polyamide component being composed of: a) 50 to 95 parts by weight, preferably 60 to 95 parts by weight, particularly preferably 75 to 90 parts by weight, of at least one alicyclic polyamide based on an alicyclic diamine having 10-20 carbon atoms and an alicyclic dicarboxylic acid having 8-18 carbon atoms; and b) 50 to 5 parts by weight, preferably 40 to 5 parts by weight, particularly preferably 25 to 10 parts by weight, of at least one linear aliphatic polyamide having an average of 9 to 12 carbon atoms in the monomer unit. The sum of the weight parts of a) and b) is 100.

[0018] In one embodiment, the composition is selected from the following forms: granular mixtures, powder mixtures, and blends.

[0019] In the granular mixture, the components (in granular form in various cases) according to a) and b) are combined and mechanically mixed—as a solid mixture. The granules may additionally contain other additives described in more detail below. The granular mixture can be processed into molded articles by melting, mixing, and molding. Thorough mixing of the melt is recommended here to obtain homogeneous molded articles. Suitable mixing equipment includes kneaders or extruders; the molding process can be carried out by injection molding, extrusion, pressing, or rolling to obtain molded articles.

[0020] In the powder mixture, components a) and b) are combined and mechanically mixed (in various cases, in powder form). The powder may contain, in addition to the components according to a) and b), other additives described in more detail below. The powder mixture can be processed into molded articles by melting, mixing, and shaping. Thorough mixing of the melt is also recommended to obtain homogeneous molded articles.

[0021] Furthermore, the composition may also be in the form of a blend obtained by melt mixing, discharge, and pulverization. The term "blend" according to the invention includes multiphase mixtures in which the components exist in domain form, as well as mixtures in which the components are so highly compatible that they are mixed at the molecular scale. Another common synonym for such a blend is an alloy. Melt mixing can be carried out in conventionally known kneading equipment, discharge is typically in strip form, and pulverization methods typically used include granulation, crushing, or grinding. Blends according to the invention may also contain other additives described in more detail below, in addition to the components according to a) and b), respectively.

[0022] In one embodiment, the alicyclic polyamide is based on PACM / MACM.

[0023] Preferably, the alicyclic polyamide is selected from: - Polyamide (PA MACM12) made from bis(3-methyl-4-aminocyclohexyl)methane and dodecanoic acid. - Polyamide (PA PACM12) made from bis(4-aminocyclohexyl)methane and dodecanoic acid, and any mixtures or copolymers thereof.

[0024] The nomenclature used here for polyamides conforms to EN ISO 1874-1. Accordingly, PA PACMX describes a polyamide composed of monomer units derived from bis(4-aminocyclohexyl)methane (PACM) and a linear dicarboxylic acid having X carbon atoms. PA MACMX represents a polyamide made from monomer units derived from bis-(3-methyl-4-aminocyclohexyl)methane (MACM) and a linear dicarboxylic acid having X carbon atoms. According to the invention, the linear dicarboxylic acid having X carbon atoms can be: X = 8: Octanoic acid (octanoic acid); X = 9: Azelaic acid (azelaic acid); X = 10: Sebacic acid (Sebacic acid); X = 11: Undecanoic acid; X = 12: Dodecanoic acid; X = 13: tridecanedioic acid (tridecanedioic acid); X = 14: Tetradecanoic acid; X = 15: Pentadecanedioic acid; X = 16: hexadecanedioic acid; X = 17: Heptadecanedioic acid; and X = 18: Octadecanedioic acid.

[0025] PA PACMX is typically prepared by melt polycondensation of PACM and dicarboxylic acid according to known methods. However, its derivatives, such as diisocyanates or dicarboxylic acid diesters derived from PACM, can also be used.

[0026] PACM exists in the form of mixtures of cis, cis, cis, trans, and trans, trans isomers. It is commercially available in various isomer ratios.

[0027] In a preferred embodiment, the PACM or its derivatives contain 5% to 30% trans and trans-isomers.

[0028] Particularly preferred is that when PA PACMX is PA PACM12, the content of the trans and trans isomers of PACM or its derivatives is 5 to 30%.

[0029] The linear aliphatic polyamide b) according to the invention has an average of 9 to 12 carbon atoms in each monomer unit. It can be prepared from a combination of diamines and dicarboxylic acids, from ω-aminocarboxylic acids, and / or from the corresponding lactams. The monomer units can be derived from lactams, ω-aminocarboxylic acids, diamines, and dicarboxylic acids, respectively, and non-limiting examples of polyamides include the following: Average of 9 carbon atoms: PA99, PA810, PA108, PA612, PA126 Average 9.5 C atoms: PA910, PA109, PA811, PA118, PA613, PA136, PA514 Average of 10 C atoms: PA10, PA1010, PA812, PA128, PA614, PA146 Average of 10.5 C atoms: PA1011, PA813, PA138, PA516 Average of 11 C atoms: PA11, PA1012, PA1210, PA913, PA139, PA814, PA148, PA616 Average of 11.5 C atoms: PA1112, PA1211, PA1013, PA1310, PA914, PA149, PA815, PA617, PA518 Average of 12 C atoms: PA12, PA1212, PA1113, PA1014, PA1410, PA816, PA618.

[0030] Other suitable polyamides of the present invention may include copolyamides that, based on a suitable selection of comonomers, satisfy the condition that the monomer units contain an average of 9 to 12 C atoms, such as copolyamides (co-PA12 / 1012) made from laurolactam, decanediamine and dodecanoic acid.

[0031] According to a preferred embodiment, the linear aliphatic polyamide (b) is selected from PA12 and PA1012.

[0032] In addition to a) and b), the compositions of the present invention may also contain other components. Examples of other components include, but are not limited to, flame retardants, stabilizers, plasticizers, glass fibers, fillers, antistatic agents, dyes, pigments, release agents, flow aids, solubilizers, and impact modifiers. The total amount of these other components is at most 50% by weight of the total weight of the composition, preferably at most 40% by weight, particularly preferably at most 30% by weight, more preferably at most 20% by weight, and very particularly preferably at most 10% by weight, or at most 5% by weight.

[0033] In particular, the other components are stabilizers.

[0034] As a stabilizer, all stabilizers known to those skilled in the art are possible.

[0035] Suitable stabilizers may include, but are not limited to, tris(2,4-di-tert-butylphenyl) phosphite.

[0036] Example The present invention will now be described in detail through the following embodiments. The scope of the present invention should not be limited to the implementation of the embodiments.

[0037] The following materials were used in the embodiments: PAPACM12: An amorphous polyamide produced from bis(4-aminocyclohexyl)methane (with approximately 20% trans and trans-stereoisomers) and dodecanoic acid.

[0038] Grilamid® TR90 natural is PAMCM12 from EMS, and is amorphous.

[0039] VESTAMID® CW1265 NC is PA1012 available from Evonik Industries AG.

[0040] VESTAMID® L1901 NC is PA12 available from Evonik Industries AG.

[0041] VESTAMID® L1600 NC is PA12 available from Evonik Industries AG.

[0042] VESTAMID® D16 is PA612 available from Evonik Industries AG.

[0043] Irgafos® 168 is a tris(2,4-di-tert-butylphenyl) phosphite from BASF.

[0044] The formulations described in Table 1 were melt-blended at 260°C in a twin-screw extruder (ZSK26MC, Coperion), and then extruded, granulated, and dried as strips. The blends were then processed into test specimens in an injection molding machine (melt temperature 270-280°C, die temperature 60-80°C). In C1, the starting material CX9704 was directly processed into test specimens as a comparative basis. Proportions are shown by weight.

[0045] Table 1 *: C1 represents Comparative Example 1.

[0046] **: E1 represents Example 1. Correspondingly, E2 to E11 represent Examples 2 to 11, respectively.

[0047] Thermoformability test: The test specimens were ISO 527 tensile test specimens. The tensile test specimens were fixed to a bending fixture with a radius of 100 mm. The test specimens with the bending fixture were then placed in an oven heated to 120°C for 0 / 5 / 10 minutes. Two specimens were tested in each group. The test specimens were then compared to check if they retained their original shape. The results are shown in Table 2.

[0048] Table 2 -: Not thermoformable, 0% retention; o: Poor thermoformability, >30% retention; +: Good thermoformability, >50% retention; ++: Excellent thermoformability, >80% retention.

[0049] Table 2 clearly shows that the blends exhibit superior thermoformability, and the test specimens retain their bent shape. This surprising phenomenon is beneficial for the thermoforming or post-processing of injection-molded parts. However, the shape memory effect observed in pure PACM12 polymers is significantly suppressed.

[0050] In summary, the compositions of the embodiments (E1-E11) according to the present invention exhibit better thermoformability compared to the pure compound of Comparative Example C1. Therefore, such excellent thermoformability can only be achieved by specific blends of the polyamides (a) and (b) according to claims.

[0051] The physical, thermal, and mechanical properties of the compositions of Examples (E1-E11) and the compositions of Comparative Example (C1) were determined and are presented in Table 3.

[0052] Table 3 .

[0053] As used herein, terms such as “include” are open-ended terms meaning “at least include” unless otherwise specified.

[0054] All references, tests, standards, documents, publications, etc., mentioned in this document are incorporated herein by reference. When numerical limits or ranges are stated, the endpoints are included. Furthermore, all values ​​and subranges within numerical limits or ranges are specifically included as if explicitly stated.

[0055] The above description is intended to enable those skilled in the art to make and use the invention, and to provide it in the context of specific applications and their requirements. Various modifications to the preferred embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of the invention. Therefore, the invention is not intended to be limited to the embodiments shown, but should be given the widest scope consistent with the principles and features disclosed herein. In this regard, it should be considered broadly that certain embodiments within the invention may not demonstrate every benefit of the invention.

Claims

1. Use of at least one linear aliphatic polyamide having an average of 9 to 12 C atoms in the monomer unit in a homogeneous amorphous composition comprising at least one cycloaliphatic polyamide based on a cycloaliphatic diamine having 10 to 20 carbon atoms and an aliphatic dicarboxylic acid having 8 to 18 carbon atoms for improving the thermoformability of the composition.

2. Use according to claim 1, the composition comprising: at least 50 wt% of a polyamide component; the polyamide component consisting of: a) 50 to 95 parts by weight of at least one cycloaliphatic polyamide based on a cycloaliphatic diamine having 10 to 20 carbon atoms and an aliphatic dicarboxylic acid having 8 to 18 carbon atoms; and b) 50 to 5 parts by weight of at least one linear aliphatic polyamide having an average of 9 to 12 C atoms in the monomer unit, wherein the sum of the parts by weight of a) and b) is 100.

3. Use according to claim 2, wherein the fraction of component a) in the polyamide component is 60 to 95 wt%, relative to the total weight of the polyamide component, and the fraction of component b) in the polyamide component is 5 to 40 wt%.

4. Use according to claim 3, wherein the fraction of component a) in the polyamide component is 75 to 90 wt%, relative to the total weight of the polyamide component, and the fraction of component b) in the polyamide component is 10 to 25 wt%.

5. Use according to claim 1, wherein the cycloaliphatic polyamide a) is PACM / MACM based.

6. Use according to claim 5, wherein the cycloaliphatic polyamide a) is selected from the group consisting of PA MACM12 and PA PACM12.

7. Use according to claim 6, wherein the trans, trans-isomer content of bis(4- aminocyclohexyl)methane (PACM) is 5 to 30 wt% of the total PACM.

8. Use according to claim 1, wherein the linear aliphatic polyamide b) is selected from the group consisting of PA 12, PA 1012.

9. Use according to claim 1, wherein the composition is in a form selected from the group consisting of a pellet mixture, a powder mixture and a blend.

10. Use according to claim 2, further comprising up to 50 wt% of at least one component selected from the group consisting of flame retardants, stabilizers, plasticizers, glass fibers, fillers, antistatic agents, dyes, pigments, mold release agents, flow aids, solubilizers and impact modifiers.

11. Use according to claim 10, wherein the at least one component is a stabilizer.

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