Polyamide composition and articles prepared therefrom

Abstract

This invention relates to a polyamide composition comprising a linear aliphatic polyamide having a) an excess of COOH groups of 20 to 120 mmol / kg, or b) an excess of NH2 groups of 20 to 120 mmol / kg; an acid-modified polymer; and an amine-modified polymer. The invention also discloses a method for manufacturing the composition and articles made from the polyamide composition.

Description

Technical Field

[0001] This invention relates to polyamide compositions and articles made therefrom. Prior Technology

[0002] Polyamide is a candidate material for various applications due to its chemical and thermal stability, good processability, and mechanical strength.

[0003] There is a market demand for polyamide compositions that offer good workability and high mechanical strength. In the past, mechanical strength could be adjusted by adding auxiliaries or additives (such as inorganic fillers, impact modifiers, and / or compatibilizers). However, it has been found that these additives may enhance one set of properties while sacrificing another. Therefore, there is a need for polyamide compositions that achieve a good balance between performance and high impact strength.

[0004] The published European patent application EP2778190 discloses a polyamide molding material in which an impact modifier in the form of a maleic anhydride-modified styrene-ethylene / butene-styrene block copolymer is introduced into the polyamide composition.

[0005] Various polyamide compositions containing acid-modified or amine-modified polymers are known in the prior art. US2013 / 092233 discloses a polyamide composition containing PA12, a polyamine-polyamide graft copolymer, and polybutylene terephthalate. CN115124828 discloses a mixture of PA12, a copolymer of butene and allylamine, and a maleic anhydride-modified ethylene / propylene copolymer. US2004 / 059056 discloses a mixture of polyamide 6, amine-functionalized polyamide 12, and an ethylene / ethyl acrylate / maleic anhydride statistical copolymer. JP2012-092209 discloses a composition comprising polyamide 6, an amine-modified / modified styrene-ethylene-butene styrene block polymer, and polyethylene terephthalate. A composition of polyamide 66, amine-modified polymer, acid-terminated polyamide 6I and filler is disclosed in JP2022-018249. Summary of the Invention

[0006] One object of the present invention is to provide a polyamide composition that can simultaneously achieve the desired properties, especially high mechanical strength over a wide temperature range.

[0007] This objective can be achieved by providing a polyamide composition comprising linear aliphatic polyamide, acid-modified polymer, and amine-modified polymer.

[0008] This novel polyamide composition demonstrates high mechanical strength over a temperature range of -40°C to 40°C.

[0009] The amine-modified polymer has a comonomer selected from at least ethylene, propylene, 1-butene, 2-butene, butadiene, and styrene.

[0010] The acid-modified polymer has at least one comonomer selected from ethylene, propylene, 1-butene, 2-butene, butadiene, and styrene, and at least one anhydride modifier selected from maleic anhydride, itaconic anhydride, or citraconic anhydride.

[0011] The amine-modified polymer is 0.5 wt.% to 24.5 wt.% based on the total weight of the polyamine composition, preferably 1 wt.% to 19 wt.%.

[0012] The acid-modified polymer is 0.5 wt.% to 24.5 wt.% based on the total weight of the polyamide composition, preferably 1 wt.% to 19 wt.%.

[0013] In one preferred system of the present invention, the sum of the weight percentages of the amine-modified polymer and the acid-modified polymer based on the total weight of the polyamide composition is 1 wt.% to 25 wt.%, more preferably 2 wt.% to 20 wt.%, and even more preferably 4 wt.% to 18 wt.%.

[0014] In one preferred system of the present invention, the mass ratio of amine-modified polymer to acid-modified polymer is 0.02:1 to 1:0.02, more preferably 0.1:1 to 1:0.1, and even more preferably 0.3:1 to 1:0.3.

[0015] The composition contains 75 to 99 wt.%, more preferably 80 to 98 wt.%, of a linear aliphatic polymer based on the total weight of the polyamide composition. Preferably, the polyamide is selected from the group consisting of linear aliphatic polyamides having an average of 8 to 14 carbon atoms in the monomer unit.

[0016] Preferably, the polyamide is selected from the group consisting of (b1) AB type polyamide; or (b2) AABB type polyamide; or any mixture or copolymer thereof. AB type is preferred.

[0017] Preferably, the impact strength of a sample made from the polyamide composition, measured at 40°C according to ISO 179, is not less than 60 kJ / m², more preferably 70 kJ / m².

[0018] Another aspect of the present invention is a method for manufacturing the polyamide composition described above. The method includes the step of mixing polyamide, an acid-modified polymer, and an amine-modified polymer to obtain the polyamide composition. The acid-modified polymer and the amine-modified polymer may be added to the polyamide sequentially or simultaneously. Furthermore, these modified polymers may be mixed in the form of a dry blend.

[0019] Another object of the present invention is to provide an article made from the polyamide composition.

[0020] Another aspect of the present invention is the use of the above-mentioned polyamide composition in various applications, including extruded tubes (including multilayer structures for automotive applications, such as fuel delivery and cooling lines; air brake lines; lines for oil and gas (including hydrogen); transportation and lining applications); coating formulations for metal coatings; injection-molded parts for sports (shoe soles, ski boots) and other industrial applications (e.g., housings). Implementation

[0021] The polyamide composition according to the present invention comprises polyamide, acid-modified polymer, and amine-modified polymer. This polyamide composition achieves good impact strength.

[0022] The impact strength of the sample, measured at 40℃ according to ISO 179, shall not be less than 60 kJ / m2, preferably 70 kJ / m2.

[0023] Polyamide compositions can be processed into objects using melting and molding methods known to those skilled in the art, such as selective laser sintering, composite filament manufacturing, selective thermal sintering, fusion deposition modeling, fused filament manufacturing, injection molding, extrusion, pressing, or calendering.

[0024] This item may be used in one of the following fields: electrical equipment, sporting goods, optical equipment, health care products, household appliances, communication technology, automotive technology, energy and drive technology, mechanical engineering, goggles, protective covers, enclosures, or medical devices. Polyamide [ ]

[0025] The polyamides used in this invention may comprise at least one of the group consisting of linear aliphatic polyamides having an average of 8 to 14 carbon atoms in the monomer unit. [Linear aliphatic polyamide] [ ]

[0026] The linear aliphatic polyamide preferably has an average of 8 to 12 carbon atoms in each monomer unit. The polyamide can be prepared from a combination of diamine and dicarboxylic acid (AABB type), ω-aminocarboxylic acid, and / or the corresponding lactamine (AB type). The monomer unit is thus a unit derived from lactamine, ω-aminocarboxylic acid, diamine, or dicarboxylic acid. For example, the following polyamides are suitable: - Average of 8 carbon atoms: PA88, PA79, PA97, PA610, PA106 - Average 8.5 carbon atoms: PA89, PA98, PA611, PA116, PA512 - Average of 9 carbon atoms: PA99, PA810, PA108, PA612, PA126 - Average 9.5 carbon atoms: PA910, PA109, PA811, PA118, PA613, PA136, PA514 - Average of 10 carbon atoms: PA10, PA1010, PA812, PA128, PA614, PA146 - Average of 10.5 carbon atoms: PA1011, PA813, PA138, PA516 - Average of 11 carbon atoms: PA11, PA1012, PA1210, PA913, PA139, PA814, PA148, PA616 - Average 11.5 carbon atoms: PA1112, PA1211, PA1013, PA1310, PA914, PA149, PA815, PA617, PA518 - Average of 12 carbon atoms: PA12, PA1212, PA1113, PA1014, PA1410, PA816, PA618

[0027] Suitable polyamides also include copolyamides, which are based on the selection of suitable comonomers that meet the constraint that the monomer unit contains an average of 8 to 12 carbon atoms, such as the copolyamide (co-PA12 / 1012) composed of laurylamine, decanediamine, and dodecanoic acid. It is worth noting that the components used can also be mixtures of suitable polyamides, where sufficient compatibility is advantageous.

[0028] Type AB is preferred.

[0029] The preferred linear aliphatic polyamides used are PA612 and PA1010. PA1012, PA11 or PA12, with PA11 or PA12 being particularly preferred.

[0030] In one system of the present invention, the linear aliphatic polyamide has an excess of 20 to 120 mmol / kg of COOH groups. The excess COOH groups refer to COOH groups minus NH₂ groups, expressed in mmol / kg. In another system of the present invention, the linear aliphatic polyamide has an excess of 20 to 120 mmol / kg of NH₂ groups. The excess NH₂ groups refer to NH₂ groups minus COOH groups, expressed in mmol / kg.

[0031] Determination of COOH groups: Weigh 2.0 g (expected value less than 15 mmol / kg) or 1.0 g (expected value greater than 15 mmol / kg) of sample into a weighing container. Add approximately 40 mL (or 20 mL) of benzyl alcohol to the constant-temperature titration container. Then add the sample to the benzyl alcohol and dissolve the sample under inert gas and stirring for 10 minutes (or 15 minutes). After dissolution, add 3 drops of indicator solution and titrate rapidly with potassium hydroxide solution (KOH aqueous solution) (concentration 0.1 mol / L).

[0032] Determination of NH2 groups: Weigh 0.5 g of sample and add 50 ml of m-cresol. Heat to 100 °C (140 °C may be used if necessary) to dissolve the sample within 1 hour. After cooling to room temperature, add 5 ml of methanol and begin potentiometric titration. For evaluation, subtract the blank value of the solvent mixture. [Acid-modified polymer] [ ]

[0033] Acid-modified polymers can refer to a class of copolymers obtained by acid functionalizing a base polymer. Acid-modified polymers can be prepared by acid modification of a base polymer with an unsaturated acid or anhydride as a functionalizing agent. This acid modification method can be carried out by grafting an unsaturated carboxylic acid and / or an unsaturated carboxylic acid derivative onto the base polymer. Preferably, a carboxylic acid or carboxylic acid derivative selected from the group consisting of unsaturated carboxylic acid esters and unsaturated carboxylic acid anhydrides is used. The conditions for grafting the base polymer are well known to those skilled in the art. The macromolecules of acid-modified polymers contain carboxyl or anhydride groups introduced through the modification method.

[0034] An unsaturated carboxylic acid is a carboxylic acid having at least one unsaturated carbon-carbon bond. Preferably, the unsaturated carboxylic acid is selected from one or more of acrylic acid, methacrylic acid, α-ethylacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, aconitic acid, tetrahydrophthalic acid, or butenylsuccinic acid.

[0035] Unsaturated carboxylic acid esters are esters of unsaturated carboxylic acids. Preferably, the unsaturated carboxylic acid ester is selected from one or more esters of acrylic acid, methacrylic acid, α-ethylacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, aconitic acid, tetrahydrophthalic acid, or butenylsuccinic acid.

[0036] Unsaturated carboxylic anhydrides are anhydrides of unsaturated dicarboxylic acids. Preferably, the unsaturated carboxylic anhydride is selected from one or more of maleic anhydride, itaconic anhydride, or citraconic anhydride.

[0037] Among carboxylic acids and carboxylic acid derivatives, maleic anhydride is preferred.

[0038] The base polymer may comprise homopolymers or copolymers. Homopolymers or copolymers may be addition polymers or condensation polymers. Regarding addition polymers, they may contain at least one monomer or comonomer selected from ethylene, propylene, butene, styrene, butadiene, any other olefin, (meth)acrylic acid, (meth)acrylate, (meth)acrylamide, or (meth)acrylonitrile. Regarding condensation polymers, they may comprise one or more of polyethers, polyesters, polycarbonates, polyurethanes, polyureas, polyamides, phenolic resins, epoxy resins, polysiloxanes, etc. The base polymer may comprise, for example, polyethylene (PE), polypropylene (PP), or styrene-ethylene-butene-styrene copolymer (SEBS), wherein SEBS is preferred.

[0039] The illustrated acid-modified polymer has at least one comonomer selected from ethylene, propylene, 1-butene, 2-butene, butadiene, and styrene, and at least one anhydride modifier selected from maleic anhydride, itaconic anhydride, or citraconic anhydride. Preferred comonomers are styrene, ethylene, and butene. The acid-modified polymer may contain 90 wt.% to 99.8 wt.%, more preferably 97 wt.% to 99 wt.%, of the comonomer based on its weight. Maleic anhydride is a preferred anhydride modifier. The acid-modified polymer contains 0.2 wt.% to 3 wt.%, of the anhydride modifier based on its weight.

[0040] As examples, acid-modified polymers include polyethylene-grafted maleic anhydride, maleic anhydride-grafted PE, maleic anhydride-grafted PP, styrene-maleic anhydride copolymer, maleic anhydride-methyl methacrylate copolymer, maleic anhydride-grafted SEBS, or maleic anhydride-acrylamide copolymer. Maleic anhydride-grafted SEBS is the preferred option.

[0041] According to the present invention, the degree of functionalization is preferably from 0.5 wt.% to 2.5 wt.%, more preferably from 1.0 wt.% to 2.0 wt.%, and even more preferably from 1.2 wt.% to 1.8 wt.%, based on the total content of the acid-modified polymer.

[0042] This invention observes that adding acid-modified polymers to polyamide compositions can improve their mechanical strength, particularly impact strength. Without being bound by any theory, acid-modified polymers contain terminal carboxyl groups, which can react with unreacted amine groups in the polyamide during processing. Therefore, acid-modified polymers may achieve high compatibility with polyamides. However, some acid-modified polymers, such as maleic anhydride-modified styrene-ethylene-butene-styrene block copolymers (MAH-SEBS), may cause visually noticeable yellowing in the resulting polyamide compositions. [Amine-modified copolymer] [ ]

[0043] Amine-modified polymers are preferably copolymers with amine end groups. Amine-modified copolymers can be prepared from a base polymer using methods known to those skilled in the art. Exemplary methods include nitration followed by reduction, condensation followed by hydrogenation, and direct amination.

[0044] The base polymer may comprise homopolymers or copolymers. The homopolymer or copolymer may have at least one monomer or comonomer selected from ethylene, propylene, butene, styrene, butadiene, any other olefin, (meth)acrylic acid, (meth)acrylate, (meth)acrylamide, or (meth)acrylonitrile, ethers, esters, carbamates, ureas, or siloxanes. The amount of one comonomer in the copolymer is from 10 wt.% to 99 wt.% based on the weight of the copolymer.

[0045] As a preferred example, the amine-modified polymer comprises amine-modified polystyrene-poly(ethylene / butene) block-polystyrene (amine-modified SEBS).

[0046] The present invention will be illustrated by the following examples and comparative examples. [Materials and Testing] [ ]

[0047] The following materials were used in the embodiments:

[0048] VESTAMID L1901 nf(PA12 COOH), purchased from Evonik Operations GmbH is a polyamide 12 with an excess of 61 mmol / kg of COOH groups.

[0049] VESTAMID Z4887 nf(PA12 NH2), purchased from Evonik Operations GmbH, is a polyamide 12 with an excess of NH2 groups of 62 mmol / kg.

[0050] Tuftec™ M1913, purchased from Asahi Kasei Corporation It is a maleic anhydride-modified SEBS thermoplastic elastomer. It is used as a compatibilizer for polar resins or as an impact modifier for engineering plastics (such as polyamide and polyester).

[0051] Tuftec™ MP10, purchased from Asahi Kasei Corporation, is an amine-modified styrene-ethylene butadiene styrene (SEBS) thermoplastic elastomer containing 30% polystyrene.

[0052] The content of residual carboxyl groups and residual amine groups in the polymer composition was determined by titration.

[0053] Regarding the carboxyl groups in polyamide, the polymer composition was dissolved in benzyl alcohol under heating, and then titrated at 185°C with an ethylene glycol solution of potassium hydroxide (KOH) using phenolphthalein as an indicator.

[0054] Regarding the amine groups in polyamide, the polymer composition was dissolved in distilled m-cresol at 100°C and then potentiometrically titrated with an ethanol solution of perchloric acid (HClO4).

[0055] Notched impact strength was determined using a CEAST Resil Impactor 6967.000 according to ISO 179 / 1eA (Charpy) for tensile specimens of ISO 527 type 1A (with both ends cut off, dimensions 80mm × 10mm × 4mm) at a temperature of (23±2)℃ and a relative humidity of (50±10)%. [Example] [ ]

[0056] According to the formulations shown in Tables 1 and 2, all polyamide components were mixed, unloaded, and granulated using a Coperion ZSK-26cm co-rotating twin-screw extruder to obtain polymer composite materials. Polyamide was fed into the main inlet of the extruder and mixed at 240°C, while the modifier was also fed into the extruder.

[0057] The polymer composition in granular form was processed on an Engel VC 650 / 200 injection molding machine (melt temperature 240°C; mold temperature 80°C) to produce specimens for mechanical and optical testing.

[0058] Tables 1 and 2 list the mechanical and optical results of samples prepared from polyamide compositions of examples (E1 to E6), comparative examples (C1 to C6), and raw materials (R1 and R2), respectively.

[0059]

[0060]

[0061] When a small amount of acid modifier is introduced as a compatibilizer into an amine impact modifier system, the impact strength can be improved (Examples E1 to E6).

[0062] The results in Tables 1 and 2 are only comparable when the same amount of modified polymer is used at the same temperature.

[0063] For amine-terminated PAs, comparative examples showed no significant improvement even when the modified polymer was increased from 10% to 15% by weight (C5→C6). Similarly, for acid-terminated PAs, the improvement was not significant even when the modified polymer was increased from 5% to 15% by weight (C2→C4). Comparing Comparative Example C6 with Examples E5 and E6 clearly shows that the combination of amine-modified and acid-modified polymers in PA12 achieves a significant improvement in impact strength across the entire temperature range. The same effect was observed when Comparing Comparative Example C5 with Example E1. The same trend was also observed when Comparing Comparative Examples C3 and C4 with Examples E2, E3, and E4, thus confirming this unexpected effect.

Claims

1. A polyamide composition comprising, based on the total weight of the polyamide composition: A) 75 to 99 wt.% of a linear aliphatic polyamide having a) 20 to 120 mmol / kg of excess COOH groups, determined by the method disclosed in the specification, or b) 20 to 120 mmol / kg of excess NH2 groups, determined by the method disclosed in the specification; B) 0.5 wt.% to 24.5 wt.% of an acid-modified polymer, wherein the acid-modified polymer has at least one comonomer selected from ethylene, propylene, 1-butene, 2-butene, butadiene, and styrene, and at least one anhydride modifier selected from maleic anhydride, itaconic anhydride, or citraconic anhydride; and C) 0.5 wt.% to 24.5 wt.% of an amine-modified polymer, wherein the amine-modified polymer has at least one comonomer selected from ethylene, propylene, 1-butene, 2-butene, butadiene, and styrene.

2. The polyamide composition of claim 1, wherein the amine-modified polymer is 1 wt.% to 19 wt.% based on the total weight of the polyamide composition.

3. The polyamide composition of claim 1, wherein the acid-modified polymer is 1 wt.% to 19 wt.% based on the total weight of the polyamide composition.

4. The polyamide composition of claim 1, wherein the sum of the weight percentages of the amine-modified polymer and the acid-modified polymer based on the total weight of the polyamide composition is from 1 wt.% to 25 wt.%.

5. The polyamide composition of claim 1, wherein the mass ratio of the amine-modified polymer to the acid-modified polymer is from 0.02:1 to 1:0.

02.

6. The polyamide composition of claim 1, wherein the mass ratio of the amine-modified polymer to the acid-modified polymer is 0.1:1 to 1:0.

1.

7. The polyamide composition of claim 1, wherein the mass ratio of the amine-modified polymer to the acid-modified polymer is from 0.3:1 to 1:0.

3.

8. The polyamide composition of claim 1, wherein the polyamide is selected from the group consisting of: linear aliphatic polyamides having an average of 8 to 14 carbon atoms in the monomer unit.

9. The polyamide composition of claim 1, wherein the polyamide is selected from the group consisting of: (b1) AB type polyamide; or (b2) AABB type polyamide; or any mixture or copolymer thereof.

10. The polyamide composition of claim 1, wherein a sample made from the polyamide composition has a notched impact strength of not less than 60 kJ / m2 as measured at 40°C according to ISO 179.

11. A method for manufacturing a polyamide composition as claimed in any one of claims 1 to 10, wherein the polyamide, the acid-modified polymer, and the amine-modified polymer are mixed.

12. An article made from a polyamide composition as claimed in any one of claims 1 to 10.

13. Use of a polyamide composition as claimed in any one of claims 1 to 10, for use in extruded tubing for fuel delivery, cooling lines, air brake lines, oil and gas transport lines; for use in linings; for use in coating formulations for metal coatings; for use in injection-molded parts for motion; and for use in housings.