Polyamide composition and method for preparing ultra-light microcellular foam by using same
By combining impact-resistant modified rubber and copper-containing stabilizer in polyamide and obtaining a microporous structure through heating, the problem of thermal aging of polyamide products at high temperatures is solved, and its impact resistance and thermal aging stability are significantly improved.
Patent Information
- Application Number
- CN202411786189.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-06
- Publication Date
- 2025-02-28
AI Technical Summary
Polyamide products are prone to thermal aging at high temperatures, resulting in reduced mechanical properties.
Using a polyamide composition, including 20.0 wt% to 99.0 wt% polyamide, 0.1 wt% to 9.0 wt% impact modified rubber, 0.1 wt% to 3.0 wt% isocyanate group compound, 0.1 wt% to 65.0 wt% filler, 0.1 wt% to 2.0 wt% additive and 0.1 wt% to 5.0 wt% copper-containing stabilizer, the microporous honeycomb structure is obtained by heating the composition to at least 80°C.
Effectively improves the impact resistance and thermal aging stability of polyamides, ensuring excellent retention of mechanical properties at temperatures up to 210°C.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of polyamide, and in particular relates to a polyamide composition and a method for preparing the same by ultra-light microporous foaming. Background Art
[0002] Polyamide is a synthetic polymer widely used in the manufacture of a variety of shaped articles, including molded parts and injection molded parts, often used in the electrical industry, the electronics industry, and the automotive industry. The molded articles and molding compositions based on polyamide for the electrical industry, the electronics industry, and the automotive industry must generally meet the composite characteristic distribution profile, including good dimensional stability, high heat deformation temperature, and good mechanical properties, such as high tensile strength, tensile modulus, and tensile fatigue. However, polyamide materials generally tend to show a reduction in mechanical properties due to thermal degradation of the polymer. This effect is called heat aging. This effect can occur to an undesirable degree. In particular, in the case of polyamide as a thermoplastic polymer, the deterioration effect of exposure to high temperatures may be very significant. In order to improve the heat aging resistance of polyamide products, a polyamide composition and an ultra-lightweight microcellular foaming method for preparing the same are provided. Summary of the invention
[0003] In view of this, the technical problem to be solved by the present invention is to provide a polyamide composition and a method for preparing ultra-lightweight microporous foam. This solves the problem that the thermal aging characteristics of polyamide products in the prior art are relatively obvious.
[0004] In order to solve the above technical problems, the present invention discloses a polyamide composition, characterized in that it comprises: a) 20.0 wt % to 99.0 wt % of at least one polyamide comprising at least one carboxyl group; b) 0.1 wt % to 9.0 wt % of at least one impact-modified rubber; c) 0.1 wt % to 3.0 wt % of at least one compound having at least one isocyanate group; d) 0.1 wt.% to 65.0 wt.% of at least one filler; e) 0.1 wt.% to 2.0 wt.% of at least one additive; f) 0.1 wt. % to 5.0 wt. % of at least one copper-containing stabilizer; The wt % of a) to f) are relative to the total weight of the composition.
[0005] Furthermore, the above-mentioned polyamide is selected from: polyamides obtained by polycondensation between at least one linear aliphatic dicarboxylic acid and an aliphatic or cyclic diamine or at least one aromatic dicarboxylic acid and an aliphatic or aromatic diamine.
[0006] Furthermore, the above-mentioned polyamide includes starburst-shaped or H-shaped macromolecular chains.
[0007] Furthermore, the filler is glass fiber.
[0008] Furthermore, the rubber contains at least one functional group capable of reacting with the polyamide, and the functional group is selected from a carboxylic acid group, an epoxy group, an anhydride group, an oxazoline group, a maleimide group or a mixture thereof.
[0009] Furthermore, the stabilizer comprises a copper compound and an alkali metal halide.
[0010] Further, the combined weight of the copper compound and the alkali metal halide will total from 0.01 wt % to 3 wt % based on the total weight of the polyamide composition.
[0011] A method for preparing ultra-lightweight microporous foam, characterized in that it comprises at least the following steps: A. heating the composition to at least 80° C.; B. Obtain a microporous honeycomb structure.
[0012] Furthermore, in the above step A, a pore former, a plasticizer, a filler, a surfactant, a stabilizer, a matting agent, a colorant, a light stabilizer and an antistatic agent are added.
[0013] Further, the molding technique used is selected from the group consisting of extrusion, injection molding, thermoforming molding, compression molding and blow molding.
[0014] Compared with the prior art, the present application can obtain the following technical effects: The present invention combines the impact-modified rubber and the copper-containing stabilizer in the above-mentioned amount into the modified polyamide, which not only effectively improves the impact resistance but also effectively and unexpectedly provides excellent synergistic heat aging stability, improves the heat aging performance at a temperature of up to 210°C, ensures excellent retention of mechanical properties, and has significantly better performance than unmodified polyamide or modified polyamide containing only the impact-modified rubber or the copper-containing stabilizer.
[0015] Of course, any product implementing this application does not necessarily need to achieve all of the technical effects described above at the same time. DETAILED DESCRIPTION
[0016] The following will explain the implementation methods of the present application in detail with examples, so that the implementation process of how the present application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.
[0017] A polyamide composition comprising: a) 20.0 wt % to 99.0 wt % of at least one polyamide comprising at least one carboxyl group; b) 0.1 wt % to 9.0 wt % of at least one impact-modified rubber; c) 0.1 wt % to 3.0 wt % of at least one compound having at least one isocyanate group; d) 0.1 wt.% to 65.0 wt.% of at least one filler; e) 0.1 wt.% to 2.0 wt.% of at least one additive; f) 0.1 wt. % to 5.0 wt. % of at least one copper-containing stabilizer; The wt % of a) to f) are relative to the total weight of the composition.
[0018] The polyamide is selected from the group consisting of polyamides obtained by polycondensation of at least one linear aliphatic dicarboxylic acid with an aliphatic or cyclic diamine or at least one aromatic dicarboxylic acid with an aliphatic or aromatic diamine, by adding monomers for regulating the chain length, such as, in particular, diamines, dicarboxylic acids, monoamines and / or monocarboxylic acids, before or during the polymerization of the monomers of the polyamide, and also by mixing, which is obtained by melt mixing the polyamide with monomers for changing the chain length, such as, in particular, diamines, dicarboxylic acids, monoamines and / or monocarboxylic acids, in particular isophthalic acid or benzoic acid can be added to the polyamide; particularly preferred polyamides are: polyamide 66, especially modified by adding monocarboxylic acids such as acetic acid or benzoic acid during the synthesis, and copolyamide 66.6, especially modified by adding monocarboxylic acids such as acetic acid or benzoic acid during the synthesis, and star polyamides can also be used, which contain star-shaped macromolecular chains and, if appropriate, linear macromolecular chains.
[0019] A method for preparing ultra-lightweight microcellular foaming, A. heating a composition to at least 80°C; B. obtaining a microcellular honeycomb structure. In step A, a pore former, a plasticizer, a filler, a surfactant, a stabilizer, a matting agent, a colorant, a light stabilizer and an antistatic agent are added. The molding technology used is selected from the group consisting of: extrusion, injection molding, thermoforming molding, compression molding and blow molding.
[0020] The filler can be any reinforcing agent, but it is preferably selected from the group consisting of calcium carbonate, glass fiber, glass flakes, glass beads, carbon fiber, talc, mica, wollastonite, calcined clay, kaolin, diatomaceous earth, magnesium sulfate, magnesium silicate, barium sulfate, titanium dioxide, sodium aluminum carbonate, barium ferrite, potassium titanate. From a morphological point of view, the filler can be selected from glass fiber.
[0021] The rubber suitable for use in the composition generally comprises at least one functional group capable of reacting with the polyamide, and more specifically a functional group capable of reacting with the amine or carboxylic acid end groups of the polyamide (functionalized rubber). The functional groups of the functionalized rubber are generally selected from carboxylic acid groups and derivatives thereof, epoxy groups, anhydride groups, oxazoline groups, maleimide groups or mixtures thereof. The functionalized rubber may be an oligomeric or polymeric compound, in which the functional groups may be incorporated by copolymerizing functional monomers during the polymerization of the impact modifier backbone or by grafting onto a preformed polymer backbone; specific examples of functionalized rubbers are notably terpolymers of ethylene, acrylate and glycidyl methacrylate, copolymers of ethylene and butyl acrylate; copolymers of ethylene, butyl acrylate and glycidyl methacrylate; ethylene-maleic anhydride copolymers; EPR grafted with maleic anhydride; styrene-maleimide copolymers grafted with maleic anhydride; SEBS copolymers grafted with maleic anhydride; styrene-acrylonitrile copolymers grafted with maleic anhydride; ABS copolymers grafted with maleic anhydride. Functionalized rubbers that have been found to be particularly effective within the framework of the present invention are amorphous copolymers of ethylene grafted with maleic anhydride.
[0022] The copper-containing stabilizer for the practice of the present invention can be characterized as comprising a copper compound and an alkali metal halide. More specifically, the copper-containing stabilizer will be mainly composed of a copper compound and an alkali metal halide, and the copper compound is selected from the group consisting of cuprous oxide, cupric oxide, cuprous salts, such as cuprous acetate, cuprous stearate, cuprous organic complexes such as cupric acetylacetonate, cuprous halides, etc. Preferably, the copper-containing stabilizer will be mainly composed of a copper halide selected from copper iodide and copper bromide and an alkali metal halide that will preferably be selected from the iodide and bromide of lithium, sodium and potassium. The copper-containing stabilizer will preferably comprise a copper compound and an alkali metal halide, with a weight ratio of 1:99 to 30:70, preferably 5:95 to 20:80, more preferably 10:90 to 15:85 compound: halide. It has been found that the weight ratio of particularly effective compound: halide is 13:87.
[0023] The polyamide comprises a starburst or H-shaped macromolecular chain; the filler is glass fiber; the rubber comprises at least one functional group capable of reacting with the polyamide, the functional group being selected from a carboxylic acid group, an epoxy group, an anhydride group, an oxazoline group, a maleimide group or a mixture thereof; the stabilizer comprises a copper compound and an alkali metal halide; the combined weight of the copper compound and the alkali metal halide will total from 0.01 wt % to 3 wt % based on the total weight of the polyamide composition.
[0024] The composition according to the invention may also contain any additives conventionally used in polyamide-based compositions for producing mouldings, examples of which may be mentioned: heat stabilizers, UV stabilizers, antioxidants, lubricants, pigments, colourants, plasticizers or impact modifiers.
[0025] Nucleation can be achieved by subjecting the polyamide composition to a rapid thermodynamic instability caused, for example, by a drop in temperature and / or pressure, with a nucleating fluid. The drop in the solubility of the nucleating fluid leads to cell nucleation and enlargement, and thus to the formation of a foam-type microcellular material. As nucleating fluids, preferably carbon dioxide and nitrogen are used.
[0026] The compositions used were as follows: Polyamide 66: PA66 with an average viscosity of 140 in formic acid; Cuprous oxide; Stabilizer K1; Fiberglass; CuI; KBr; Elastomers; Other additives: lubricants, pigments, etc.; The composition was produced by melt mixing using a co-rotating twin-screw extruder under the following conditions: screw speed: 250 rpm, flow rate: 40 kg / h, temperature profile: 250-280° C., degassing: 0.9 bar. Polyamide, 50% by weight of glass fibers, 5% of elastomer, 0.2% of additives and a certain proportion of stabilizer mentioned in the table below were mixed. The stabilizer was added at the beginning of the extruder. The pellets obtained were then molded under the following conditions: temperature profile: 280-300° C., molding temperature: 90-100° C., screw speed: 120 rpm, injection speed: 80 cm3 / s, back pressure: 10 bar.
[0027] The performance results in terms of mechanical properties retention before and after aging tests are mentioned in the following table:
[0028] The percentages are expressed as weight relative to the weight of polyamide of the composition Impact strength (Charpy unnotched impact strength) is measured according to ISO 179-1 / 1 Fu standard. Aging is carried out in ambient air at 200° C. for 31 days and then at 220° C. for 7 days.
[0029] The present invention combines the impact-modified rubber and the copper-containing stabilizer in the above-mentioned amount into the modified polyamide, which not only effectively improves the impact resistance but also effectively and unexpectedly provides excellent synergistic heat aging stability, improves the heat aging performance at a temperature of up to 210°C, ensures excellent retention of mechanical properties, and has significantly better performance than unmodified polyamide or modified polyamide containing only the impact-modified rubber or the copper-containing stabilizer.
[0030] The above description shows and describes several preferred embodiments of the present invention, but as mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the invention concept described herein through the above teachings or the technology or knowledge of the relevant field. Changes and variations made by those skilled in the art do not depart from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.
Claims
1. A polyamide composition, characterized in that include: a) 20.0 wt % to 99.0 wt % of at least one polyamide comprising at least one carboxyl group; b) 0.1 wt % to 9.0 wt % of at least one impact-modified rubber; c) 0.1 wt % to 3.0 wt % of at least one compound having at least one isocyanate group; d) 0.1 wt.% to 65.0 wt.% of at least one filler; e) 0.1 wt.% to 2.0 wt.% of at least one additive; f) 0.1 wt. % to 5.0 wt. % of at least one copper-containing stabilizer; The wt % of a) to f) are relative to the total weight of the composition.
2. The polyamide composition according to claim 1, characterized in that The polyamide is chosen from polyamides obtained by polycondensation between at least one linear aliphatic dicarboxylic acid and an aliphatic or cyclic diamine or at least one aromatic dicarboxylic acid and an aliphatic or aromatic diamine.
3. The polyamide composition according to claim 2, characterized in that The polyamide includes starburst-shaped or H-shaped macromolecular chains.
4. The polyamide composition according to claim 1, characterized in that The filler is glass fiber.
5. The polyamide composition according to claim 1, characterized in that The rubber comprises at least one functional group capable of reacting with the polyamide, the functional group being selected from carboxylic acid groups, epoxy groups, anhydride groups, oxazoline groups, maleimide groups or mixtures thereof.
6. The polyamide composition according to claim 1, characterized in that The stabilizer comprises a copper compound and an alkali metal halide.
7. The polyamide composition according to claim 1, characterized in that The combined weight of the copper compound and the alkali metal halide will total from 0.01 wt% to 3 wt%, based on the total weight of the polyamide composition.
8. The method for preparing ultra-lightweight microcellular foaming from a polyamide composition according to claim 1, characterized in that: At least the following steps are included: A. heating the composition to at least 80° C.; B. Obtain a microporous honeycomb structure.
9. The method for preparing ultra-lightweight microcellular foam according to claim 8, characterized in that: In step A, pore formers, plasticizers, fillers, surfactants, stabilizers, matting agents, colorants, light stabilizers, and antistatic agents are added.
10. The method for preparing ultra-lightweight microcellular foam according to claim 8, characterized in that: The molding technique used is selected from the group consisting of extrusion, injection molding, thermoforming molding, compression molding and blow molding.