Light-heat aging resistant polyamide resin, its preparation method and application

Abstract

The application provides a light-heat aging resistant polyamide resin and a preparation method and application thereof, raw materials for preparing the polyamide resin include reactive monomers and additives; the reactive monomers include binary acid and binary amine; the additives include a compounded heat stabilizer, the compounded heat stabilizer includes an amide bond containing compound, copper acetate and potassium iodide; by adding the amide bond containing compound, the copper acetate and the potassium iodide as the compounded heat stabilizer in the raw materials, the problem of thermal decomposition of the polyamide resin caused by high temperature is solved in the polymerization process, and then the light-heat aging resistance of the polyamide resin is effectively improved, and the production process and cost are not additionally increased.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polyamide and specifically relates to a light and heat aging resistant polyamide resin and a preparation method and application thereof. BACKGROUND

[0002] Polyamide is commonly known as nylon, which refers to a linear thermoplastic polymer with a repeating structural unit of an amide group (-CO-NH-) in the main chain; the amide group in polyamide is polar and forms intermolecular hydrogen bonds, so the polyamide resin has excellent characteristics such as strong toughness, wear resistance, impact resistance, fatigue resistance, corrosion resistance, non-toxicity, good spinnability, high fiber strength, etc., and is mainly used in automobiles, electronics, spinning and other aspects.

[0003] Since the bond dissociation energy of C-N bond is low (only 275.88 kJ / mol), the amide bond will first break when heated, generating small molecules such as cyclopentanone, CO and CO2, resulting in poor performance, and molecular chain scission is easily caused by side reactions such as thermal oxidative degradation during high-temperature polymerization, extrusion and injection molding, especially after multiple high-temperature processing, which makes the phenomenon more serious, and also leads to a decrease in product performance. More importantly, yellowing during spinning can easily cause fiber breakage, resulting in hairiness or assembly pressure increase, affecting the yield of finished products and leading to a substantial increase in cost. Long-term high-temperature use has been a difficult problem for the polyamide industry to solve.

[0004] At present, the commonly used method to improve the high-temperature heat aging resistance of polyamide is to add a heat stabilizer and an antioxidant after the completion of polyamide polymerization, and to use post-extrusion modification to improve the heat resistance of the product. CN115651398A discloses a heat-stable regenerated polyamide composition and a preparation method thereof. The polyamide composition is composed of the following components in parts by weight: 100 parts of polyamide regenerated resin, 10-60 parts of reinforcing agent, 0.1-1 parts of inorganic stabilizer and 0.1-1 parts of lubricant. The polyamide composition obtained in the invention uses polyamide regenerated resin as the main raw material, is modified for heat stability by an inorganic stabilizer composed of cuprous iodide and potassium iodide, and is modified for reinforcement by glass fiber, thereby solving the problem of long-term heat stability of the regenerated polyamide material. The polyamide composition obtained in the invention has excellent heat stability. However, this method of post-extrusion modification has limited effect on the improvement of the light and heat aging resistance of the polyamide resin, and increases the production process and cost.

[0005] Therefore, it is a technical problem urgently needed to be solved in the field to develop a polyamide resin with excellent light and heat aging resistance without the need to add new production processes. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a light and heat aging resistant polyamide resin and a preparation method and application thereof, wherein the light and heat aging resistant polyamide resin is prepared by adding a compound containing an amide bond, copper acetate and potassium iodide as a complex heat stabilizer in the preparation raw material, thereby solving the problem of thermal decomposition of the polyamide resin caused by high temperature during polymerization, effectively improving the light and heat aging resistance of the polyamide resin without additional production processes and costs.

[0007] To achieve this purpose, the present application adopts the following technical solutions:

[0008] In a first aspect, the present application provides a light and heat aging resistant polyamide resin, wherein the preparation raw material of the polyamide resin comprises a reactive monomer and an additive.

[0009] The reactive monomer comprises a diacid and a diamine.

[0010] The additive comprises a complex heat stabilizer, wherein the complex heat stabilizer comprises a compound containing an amide bond, copper acetate and potassium iodide.

[0011] Through continuous experimental exploration and theoretical thinking, the present application found that the fundamental reason for yellowing and aging of polyamide resin and its composition is that the polyamide resin begins to decompose and oxidize during high-temperature polymerization and other processing processes, resulting in an increase in the content of amino groups, and nitrogen oxides NO x in the air can cause oxidation of the nylon amino group, generating yellow quinone structures, resulting in yellowing and performance degradation; the present application adds a compound containing an amide bond, copper acetate and potassium iodide for compounding as a complex heat stabilizer in the preparation raw material, wherein the compound containing an amide bond can be compatible with the polyamide resin through "molecular recognition" or cross-linking reaction by forming hydrogen bonds with the polyamide resin, and the copper acetate and potassium iodide can form a complex with the molecular chain of the polyamide, thereby increasing the bond energy of the amide bond, improving the decomposition bond energy, and thereby improving the decomposition and oxidation temperature of the final obtained polyamide resin, thereby solving the problem of thermal decomposition of the polyamide resin caused by high temperature during polymerization, and effectively improving the light and heat aging resistance of the polyamide resin without additional production processes and costs.

[0012] Preferably, the mass of the reactive monomer is not less than 95%, for example 95.5%, 96%, 96.5%, 97%, 97.5%, 98% or 98.5%, etc., based on the total mass of the reactive monomer and the additive being 100%.

[0013] Preferably, the dicarboxylic acid includes any one or a combination of at least two of the following: adipic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, or octadecanoic acid.

[0014] Preferably, the diamine includes any one or a combination of at least two of the following: hexamethylenediamine, pentaethylenediamine, heptaethylenediamine, octanediamine, nonanediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecananediamine, or octadecanediamine.

[0015] Preferably, the molar ratio of the dicarboxylic acid to the diamine is 1:(1 to 1.08), for example, 1:1.01, 1:1.02, 1:1.03, 1:1.04, 1:1.05, 1:1.06 or 1:1.07, etc.

[0016] Preferably, the amount of heat stabilizer added to the raw materials for preparing the polyamide resin is 200-600 ppm, such as 250 ppm, 300 ppm, 350 ppm, 400 ppm, 450 ppm, 500 ppm or 550 ppm.

[0017] As a preferred technical solution of the present invention, the amount of compound heat stabilizer added in the raw materials for preparing polyamide resin is limited to 200-600 ppm. On the one hand, if the amount of compound stabilizer added is too low, the resulting polyamide resin will have insufficient resistance to photothermal aging. On the other hand, if the amount of compound stabilizer added is too high, the resulting polyamide resin will have too fast a polymerization rate, which cannot be controlled, resulting in uneven molecular weight distribution.

[0018] It should be noted that the above-mentioned "raw materials for preparing polyamide resin" also include water, and water is used as a solvent to prepare polyamide salt solution.

[0019] Preferably, the mass ratio of the amide-containing compound, copper acetate, and potassium iodide is (1-2):(1-2):1.

[0020] The mass ratio of the amide-containing compound to potassium iodide is 1.2:1, 1.4:1, 1.6:1, or 1.8:1, etc., and the mass ratio of copper acetate to potassium iodide is 1.2:1, 1.4:1, 1.6:1, or 1.8:1, etc.

[0021] Preferably, the amide-containing compound includes isophthalamide and / or dimethylacetamide.

[0022] Preferably, the additive further comprises any one or a combination of at least two of a catalyst, an end-capping agent, an antifoaming agent, a weathering agent, a nucleating agent, an antistatic agent, a flame retardant, an ultraviolet light resistant agent, a matting agent, or an antioxidant.

[0023] Preferably, the catalyst comprises any one or a combination of at least two of phosphoric acid, a phosphoric acid salt, phosphorous acid, a phosphorous acid salt, hypophosphorous acid, or a hypophosphorous acid salt.

[0024] Preferably, the end-capping agent comprises any one or a combination of at least two of a monofunctional amine, a di-amine, a monofunctional acid, or a di-acid.

[0025] Preferably, the monofunctional amine comprises hexylamine.

[0026] Preferably, the di-amine comprises pentamethylene diamine and / or hexamethylene diamine.

[0027] Preferably, the monofunctional acid comprises any one or a combination of at least two of acetic acid, hexanoic acid, or benzoic acid.

[0028] Preferably, the di-acid comprises any one or a combination of at least two of adipic acid, terephthalic acid, or sebacic acid, further preferably sebacic acid.

[0029] As a preferred technical solution of the present application, sebacic acid is selected as the end-capping agent, which can further improve the toughness of the polyamide resin.

[0030] Preferably, the antifoaming agent comprises a silicon-containing compound.

[0031] Preferably, the weathering agent comprises any one or a combination of at least two of a hydroquinone compound, a salicylate compound, a benzotriazole compound, a benzophenone compound, or a hindered amine compound.

[0032] Preferably, the antioxidant comprises any one or a combination of at least two of sodium phosphate, magnesium phosphate, calcium phosphate, sodium phosphite, magnesium phosphite, calcium phosphite, zinc phosphite, antioxidant H10, manganese hypophosphite, sodium hypophosphite, magnesium hypophosphite, calcium hypophosphite, or zinc hypophosphite, further preferably sodium hypophosphite.

[0033] Preferably, the matting agent comprises titanium dioxide.

[0034] In a second aspect, the present application provides a preparation method of the polyamide resin according to the first aspect, the preparation method comprising the following steps:

[0035] (1) reacting the di-acid, the di-amine, and the additive in water to obtain a nylon salt aqueous solution;

[0036] (2) pre-polymerizing and final-polymerizing the nylon salt aqueous solution obtained in step (1) to obtain the polyamide resin.

[0037] Preferably, the mass percentage of the nylon salt in the nylon salt aqueous solution in step (1) is 50-90%, for example, 55%, 60%, 65%, 70%, 75%, 80% or 85%, and the like, more preferably 50-80%, and further preferably 60-70%.

[0038] Preferably, the reaction in step (1) is carried out under nitrogen protection.

[0039] Preferably, the pressure in the pre-polymerization in step (2) is 0.5-2.5 MPa (gauge pressure), for example, 0.7 MPa, 0.9 MPa, 1.1 MPa, 1.3 MPa, 1.5 MPa, 1.7 MPa, 1.9 MPa, 2.1 MPa or 2.3 MPa, and the like, more preferably 1-2 MPa, and further preferably 1-1.5 MPa.

[0040] Preferably, the time in the pre-polymerization in step (2) is 1-2.5 h, for example, 1.2 h, 1.4 h, 1.6 h, 1.8 h, 2 h, 2.2 h or 2.4 h, and the like.

[0041] Preferably, the pressure in the final-polymerization in step (2) is -0.01--0.1 MPa (gauge pressure), for example, -0.03 MPa, -0.05 MPa, -0.07 MPa or -0.09 MPa, and the like.

[0042] Preferably, the temperature in the final-polymerization in step (2) is 230-285℃, for example, 240℃, 245℃, 250℃, 255℃, 260℃, 265℃, 270℃, 275℃ or 280℃, and the like.

[0043] Preferably, the time in the final-polymerization in step (2) is 10-60 min, for example, 20 min, 30 min, 40 min or 50 min, and the like.

[0044] Preferably, after the final-polymerization in step (2), the method further comprises a step of pressure granulation.

[0045] Preferably, the pressure in the pressure granulation is 0.1-0.5 MPa, for example, 0.15 MPa, 0.2 MPa, 0.25 MPa, 0.3 MPa, 0.35 MPa, 0.4 MPa or 0.45 MPa, and the like.

[0046] As a preferred technical solution of the present application, the preparation method comprises the following steps:

[0047] (1) reacting a dibasic acid, a dibasic amine and an additive in water to obtain a nylon salt aqueous solution;

[0048] (2) the nylon salt aqueous solution obtained in step (1) is pre-polymerized under a pressure of 0.5-2.5 MPa, and then post-polymerized under a pressure of -0.01 to -0.1 MPa at a temperature of 230-285°C for 10-60 min, and then extruded and granulated under a pressure of 0.1-0.5 MPa under the protection of a protective gas to obtain the polyamide resin.

[0049] In a third aspect, the present application provides a polyamide resin composition comprising the polyamide resin according to the first aspect.

[0050] Compared with the prior art, the present application has the following beneficial effects:

[0051] The preparation raw material of the light and heat aging resistant polyamide resin provided by the present application comprises a reactive monomer and an additive; the reactive monomer comprises a dibasic acid and a dibasic amine; and the additive comprises a compounded heat stabilizer, which comprises an amide bond-containing compound, copper acetate and potassium iodide; by adding the amide bond-containing compound, copper acetate and potassium iodide as the compounded heat stabilizer in the preparation raw material, the problem of thermal decomposition of the polyamide resin caused by high temperature is solved in the polymerization process, without additional production process and cost, and the polyamide resin with excellent light and heat aging resistance is obtained. DETAILED DESCRIPTION

[0052] The technical solutions of the present application are further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application, and should not be regarded as specific limitations on the present application.

[0053] Examples 1-8

[0054] A light and heat aging resistant polyamide resin, the specific composition and amount of the preparation raw material of which are shown in Table 1, and the amount of each raw material is "g":

[0055] Table 1

[0056]

[0057] The preparation method of the light and heat aging resistant polyamide resin provided in Examples 1-8 comprises the following steps:

[0058] (1) a 10L polymerization kettle is replaced with nitrogen three times by vacuumizing and filling nitrogen, and protected by nitrogen, and pure water, hexanediamine, adipic acid, a compounded heat stabilizer, an end-capping agent and an antioxidant are added for reaction to obtain a nylon salt aqueous solution, and hexanediamine and adipic acid are used to adjust the pH value thereof to 7.6;

[0059] (2) The oil bath temperature of the 10 L polymerizer was raised to 240 °C, and when the pressure in the polymerizer rose to 1 MPa, prepolymerization was started. The temperature was then raised to 280 °C, and the system was vacuumized to a pressure of -0.02 MPa for terminal polymerization for 25 min. Then, nitrogen was filled into the polymerizer to a pressure of 0.5 MPa, and the melt was discharged. The melt was pelletized using a pelletizer. After the pelletization was completed, the polyamide resin was obtained.

[0060] Comparative Examples 1-13

[0061] A polyamide resin was prepared using the specific components and amounts of the raw materials shown in Table 2. The amounts of the components are all in units of “g”:

[0062] Table 2

[0063]

[0064] The polyamide resins provided in Comparative Examples 1-13 were prepared in the same manner as in Example 1.

[0065] Performance tests:

[0066] The polyamide resins obtained in Examples 1-8 and Comparative Examples 1-13 were dried in a vacuum dryer at 105 °C for 4 h, and then sample strips were prepared for performance tests. The sample strips were prepared using an injection molding machine (model: ZE900III / 160H) and the following production process: temperature: 255 °C for the first stage, 265 °C for the second stage, 275 °C for the third stage, 285 °C for the fourth stage, and 275 °C for the fifth stage. The injection pressure was 80 MPa, and the production cycle was 18 s.

[0067] (1) Relative viscosity: The Ubbelohde viscometer concentrated sulfuric acid method was used for the test. The specific steps included: accurately weighing 0.5 ± 0.000 2 g of the dried polyamide sample, adding 50 mL of concentrated sulfuric acid (98%), dissolving in a 25 °C constant temperature water bath, and measuring and recording the concentrated sulfuric acid flow time t0 and the polyamide solution flow time t. The relative viscosity ηr = t / t0, where t is the solution flow time, and t0 is the solvent flow time.

[0068] (2) Melting point: The sample was tested using a differential scanning calorimeter DSC according to the detection standard “ISO 11357-3:2011 Plastics - Differential scanning calorimetry (DSC) - Part 3: Determination of melting and crystallization temperatures and melting and crystallization enthalpies” under the conditions of an ambient temperature of 23 ± 2 °C and a humidity of 50 ± 5% R.H.

[0069] (3) Tensile strength: measured according to the ISO 527-2 method, and the tensile speed during the test was 50 mm / min.

[0070] (4) Bending strength: measured according to the ISO 178 method, and the test condition was 2 mm / min.

[0071] (5) Notched impact strength: The notched impact strength of the material was tested using a cantilever pendulum impact tester. The impact strength was determined according to ISO 180-2001 method, with a notch depth of 2 mm and a pendulum energy of 2.75 J.

[0072] (6) Heat resistance: The test was conducted in accordance with the standard in section 9.5 of UL62275. The difference is that the target temperature required by the UL62275 standard is 105℃ / 135℃, while this experiment was conducted at 125℃ and humidity of 50±5. After aging for 500 hours, the tensile strength was tested after being placed at room temperature for 21 days. The tensile strength retention rate before and after the aging test was calculated.

[0073] The polyamide resin test strips obtained in Examples 1-8 and Comparative Examples 1-13 were tested according to the above test methods. The test results are shown in Tables 3 and 4.

[0074] Table 3

[0075]

[0076]

[0077] Table 4

[0078]

[0079] Based on the data in Tables 3 and 4, it can be seen that:

[0080] The polyamide resins obtained in Examples 1-3 have a relative viscosity of 2.7, a melting point of 264°C, a tensile strength of 83-88 MPa, a flexural strength of 105-112 MPa, and a notched impact strength of 4.8-6 KJ / m. 2 Heat resistance tests showed that the tensile strength after treatment at 125℃ for 500 hours was still as high as 71-84 MPa, demonstrating excellent thermal stability.

[0081] Compared with Example 1, the addition of the compound stabilizer in Examples 4 and 5 was too low and too high, respectively, which caused the overall performance of the obtained polyamide resin to decline. In particular, the heat resistance stability decreased in a gradient manner. This is because if the addition of the compound stabilizer is too low, the high temperature treatment will destroy the molecular weight structure of the polyamide, resulting in a decrease in tensile strength. If the addition is too high, the degree of polymerization during the preparation of polyamide cannot be controlled, the molecular weight distribution is uneven, and the performance is unstable.

[0082] Compared with Example 1, the mass ratio of 2-isophthalamide, copper acetate and potassium iodide in the compound stabilizer in Examples 6 to 8 is not within the preferred range of the present invention, resulting in poor synergistic effect of the three and failure to fully exert their effect, thus limiting the improvement of the performance of polyamide resin.

[0083] Compared with Example 1, the polyamide resins provided in Comparative Examples 1 to 10 all used a single type of stabilizer, while the polyamide resins provided in Comparative Examples 11 to 13 all used a combination of two stabilizers. Although both improved the mechanical properties and thermal stability of the polyamide resins to some extent, the effect was far worse than that of using a combination of 2-isophthalamide, copper acetate and potassium iodide as stabilizers.

[0084] The applicant declares that this invention illustrates a photo-thermal aging resistant resin, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this invention.

Claims

1. A polyamide resin resistant to photo- and heat aging, characterized in that, The raw materials for preparing the polyamide resin include reactive monomers and additives; The reactive monomers include diacids and diamines; The additives include compound heat stabilizers, which include compounds containing amide bonds, copper acetate, and potassium iodide; The mass ratio of the amide-containing compound, copper acetate, and potassium iodide is (1~2):(1~2):1; The compound containing an amide bond is isophthalamide.

2. The polyamide resin according to claim 1, characterized in that, With the total mass of the reactive monomer and the additive being 100%, the mass of the reactive monomer is not less than 95%.

3. The polyamide resin according to claim 1, characterized in that, The dicarboxylic acid includes any one or a combination of at least two of the following: adipic acid, glutaric acid, heptanoic acid, octanoic acid, azelaic acid, sebacic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, or octadecanoic acid.

4. The polyamide resin according to claim 1, characterized in that, The diamine includes any one or a combination of at least two of the following: hexamethylenediamine, pentapentanediamine, heptapentanediamine, octanediamine, nonanediamine, decanedanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecananediamine, or octadecanediamine.

5. The polyamide resin according to claim 1, characterized in that, The molar ratio of the dicarboxylic acid to the diamine is 1:(1~1.08).

6. The polyamide resin according to claim 1, characterized in that, The amount of heat stabilizer added in the raw materials for preparing the polyamide resin is 200~600 ppm.

7. The polyamide resin according to claim 1, characterized in that, The additives also include any one or a combination of at least two of the following: catalysts, capping agents, defoamers, weathering agents, nucleating agents, antistatic agents, flame retardants, UV stabilizers, matting agents, or antioxidants.

8. The polyamide resin according to claim 7, characterized in that, The catalyst comprises any one or a combination of at least two of phosphoric acid, phosphate, phosphorous acid, phosphite, hypophosphorous acid, or hypophosphorous acid.

9. The polyamide resin according to claim 7, characterized in that, The capping agent includes any one or a combination of at least two of the following: a monofunctional amine, a diamine, a monofunctional acid, or a dicarboxylic acid.

10. The polyamide resin according to claim 9, characterized in that, The monofunctional amines include hexylamine.

11. The polyamide resin according to claim 9, characterized in that, The diamine includes pentanediamine and / or hexanediamine.

12. The polyamide resin according to claim 9, characterized in that, The monofunctional acid includes any one or a combination of at least two of acetic acid, hexanoic acid, or benzoic acid.

13. The polyamide resin according to claim 9, characterized in that, The dicarboxylic acid includes any one or a combination of at least two of adipic acid, terephthalic acid, or sebacic acid.

14. The polyamide resin according to claim 13, characterized in that, The dicarboxylic acid is sebacate.

15. The polyamide resin according to claim 7, characterized in that, The defoamer includes silicone compounds.

16. The polyamide resin according to claim 7, characterized in that, The weather-resistant agent includes any one or a combination of at least two of the following: hydroquinone compounds, salicylates, benzotriazoles, benzophenones, or hindered amines.

17. The polyamide resin according to claim 7, characterized in that, The antioxidant is antioxidant H10.

18. The polyamide resin according to claim 7, characterized in that, The matting agent includes titanium dioxide.

19. A method for preparing the polyamide resin according to any one of claims 1 to 18, characterized in that, The preparation method includes the following steps: (1) The dicarboxylic acid, diamine and additives are reacted in water to obtain an aqueous solution of nylon salt; (2) The nylon salt aqueous solution obtained in step (1) is prepolymerized and finalized to obtain the polyamide resin.

20. The preparation method according to claim 19, characterized in that, The mass percentage of nylon salt in the nylon salt aqueous solution in step (1) is 50-90%.

21. The preparation method according to claim 20, characterized in that, The mass percentage of nylon salt in the nylon salt aqueous solution in step (1) is 50-80%.

22. The preparation method according to claim 21, characterized in that, The mass percentage of nylon salt in the nylon salt aqueous solution in step (1) is 60-70%.

23. The preparation method according to claim 19, characterized in that, The reaction described in step (1) is carried out under nitrogen protection.

24. The preparation method according to claim 19, characterized in that, The pressure of the prepolymerization in step (2) is 0.5~2.5MPa.

25. The preparation method according to claim 24, characterized in that, The pressure of the prepolymerization in step (2) is 1~2 MPa.

26. The preparation method according to claim 25, characterized in that, The pressure of the prepolymerization in step (2) is 1~1.5MPa.

27. The preparation method according to claim 19, characterized in that, The prepolymerization time in step (2) is 1~2.5h.

28. The preparation method according to claim 19, characterized in that, The final polymerization pressure in step (2) is -0.01 to -0.1 MPa.

29. The preparation method according to claim 19, characterized in that, The final polymerization temperature in step (2) is 230~285℃.

30. The preparation method according to claim 19, characterized in that, The final polymerization time in step (2) is 10~60 min.

31. The preparation method according to claim 19, characterized in that, After the final polymerization is completed in step (2), a pressure granulation step is also included.

32. The preparation method according to claim 31, characterized in that, The pressure for pressurized granulation is 0.1~0.5MPa.

33. A polyamide resin composition, characterized in that, The polyamide resin composition comprises the polyamide resin as described in any one of claims 1 to 18.

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