Polyamide molding compound having high gloss and high notch impact resistance

Abstract

The present invention relates to polyamide molding compounds that are characterized by high notch impact resistance and high gloss. These polyamide molding compounds comprise the following components or consist of these components: (A) 84.5 to 97.0 wt % of at least one amorphous or microcrystalline copolyamide selected from the group comprising PA 6I/6T/MACMI/MACMT/PACMI/PACMT/Y, PA 6I/6T/MACMI/MACMT/Y, and mixtures thereof; (B) 3.0 to 9.5 wt % of at least one specific functionalized impact resistance modifier; and (C) 0 to 6 wt % of at least one additive; wherein the weight proportions of the components (A) to (C) add up to 100 wt %. The present invention furthermore relates to molded bodies composed of this polyamide molding compound.

Claims

1. A polyamide molding compound comprising the following components: (A) 84.5 to 97.0 wt % of at least one amorphous or microcrystalline copolyamide selected from the group consisting of PA 6I/6T/MACMI/MACMT/PACMI/PACMT/Y, PA 6I/6T/MACMI/MACMT/Y, and mixtures thereof, wherein monomer Y has 7 to 14 carbon atoms and is selected from the group consisting of lactams, w-amino acids, and mixtures thereof; (B) 3.0 to 9.5 wt % of at least one functionalized impact resistance modifier comprising monomers Ba) ethylene; Bb) propylene; and Bc) 1-butene, wherein functionalization took place by copolymerization and/or by grafting with a compound selected from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic acid derivatives, unsaturated glycidyl compounds, and mixtures thereof; and (C) 0 to 6 wt % of at least one additive; wherein the weight proportions of components (A) to (C) add up to 100 wt %; wherein the polyamide molding compound has a gloss of at least 75% at an angle of 60 as determined in accordance with DIN EN ISO 2813 (2015) after treatment of a test specimen of the polyamide molding compound with a soap solution and wherein the polyamide molding compound has a notch impact resistance of at least 70 kJ/m.sup.2 as determined in accordance with DIN EN ISO 179/2 eA.

2. The polyamide molding compound in accordance with claim 1, wherein component (A) is made up of monomers: a1) 4 to 30 mol % bis(3-methyl-4-aminocyclohexyl)methane; a2) 18 to 45 mol % 1,6-hexanediamine; a3) 0 to 10 mol % bis(4-aminocyclohexyl)methane; a4) 18 to 30 mol % isophthalic acid; a5) 18 to 30 mol % terephthalic acid; and a6) 0.1 to 10 mol % of monomer Y, wherein the monomer Y has 7 to 14 carbon atoms and is selected from the group consisting of lactams, -amino acids, and mixtures thereof; wherein the proportions of the monomers a1) to a6) in the copolyamide add up to 100%; and wherein the sum of all diamine monomers substantially corresponds to the sum of all dicarboxylic acid monomers.

3. The polyamide molding compound in accordance with claim 1, wherein component (A) is an amorphous copolyamide PA 6I/6T/MACMI/MACMT/PACMI/PACMT/Y which is made up of the monomers a1) 4 to 30 mol % bis(3-methyl-4-aminocyclohexyl)methane; a2) 18 to 45 mol % 1,6-hexanediamine; a3) 0.1 to 10 mol % bis(4-aminocyclohexyl)methane; a4) 18 to 30 mol % isophthalic acid; a5) 18 to 30 mol % terephthalic acid; and a6) 0.1 to 10 mol % of monomer Y, wherein the monomer Y has 7 to 14 carbon atoms and is selected from the group consisting of lactams, -amino acids, and mixtures thereof; wherein the proportions of monomers a1) to a6) in the copolyamide add up to 100%; and wherein the sum of all diamine monomers substantially corresponds to the sum of all dicarboxylic acid monomers.

4. The polyamide molding compound in accordance with claim 3, wherein component (A) is made up of the monomers a1) 5 to 20 mol % bis(3-methyl-4-aminocyclohexyl)methane; a2) 20 to 43 mol % 1,6-hexanediamine; a3) 0.1 to 8 mol % bis(4-aminocyclohexyl)methane; a4) 20 to 29.5 mol % isophthalic acid; a5) 20 to 29.5 mol % terephthalic acid; and a6) 1 to 8 mol % monomer Y, wherein the monomer Y has 7 to 14 carbon atoms and is selected from the group consisting of lactams, co-amino acids, and mixtures thereof; wherein the proportions of the monomers a1) to a6) in the copolyamide add up to 100%; and wherein the sum of all diamine monomers substantially corresponds to the sum of all dicarboxylic acid monomers.

5. The polyamide molding compound in accordance with claim 1, wherein component (A) is an amorphous copolyamide PA 6I/6T/MACMI/MACMT/Y which is made up of monomers a1) 4 to 30 mol % bis(3-methyl-4-aminocyclohexyl)methane; a2) 18 to 45 mol % 1,6-hexanediamine; a4) 18 to 30 mol % isophthalic acid; a5) 18 to 30 mol % terephthalic acid; and a6) 0.1 to 10 mol % of monomer Y, wherein the monomer Y has 7 to 14 carbon atoms and is selected from the group consisting of lactams, co-amino acids, and mixtures thereof; wherein the proportions of monomers a1), a2), and a4) to a6) in the copolyamide add up to 100%; and wherein the sum of all diamine monomers substantially corresponds to the sum of all dicarboxylic acid monomers.

6. The polyamide molding compound in accordance with claim 5, wherein component (A) is made up of the monomers a1) 5 to 20 mol % bis(3-methyl-4-aminocyclohexyl)methane; a2) 26 to 43 mol % 1,6-hexanediamine; a4) 20 to 29.5 mol % isophthalic acid; a5) 20 to 29.5 mol % terephthalic acid; and a6) 1 to 8 mol % monomer Y, wherein the monomer Y has 7 to 14 carbon atoms and is selected from the group consisting of lactams, co-amino acids, and mixtures thereof; wherein the proportions of the monomers a1), a2), and a4) to a6) in the copolyamide add up to 100%; and wherein the sum of all diamine monomers substantially corresponds to the sum of all dicarboxylic acid monomers.

7. The polyamide molding compound in accordance with claim 1, wherein the monomer Y of the component (A) is selected from the group consisting of enantholactam (7 carbon atoms), caprylic lactam (8 carbon atoms), capric lactam (10 carbon atoms), lactam 11 (11 carbon atoms), lauric lactam (12 carbon atoms), 1,7-aminoheptanoic acid, 1,8-aminooctanoic acid, 1,11-aminoundecanoic acid, and 1,12-aminododecanoic acid, and mixtures thereof.

8. The polyamide molding compound in accordance with claim 1, wherein the proportion of component (A) in the polyamide molding compound is in the range from 87.5 to 96.5 wt %, with respect to the sum of components (A) to (C); and/or the proportion of component (B) in the polyamide molding compound is in the range from 3.5 to 8.5 wt %, with respect to the sum of components (A) to (C); and/or the proportion of component (C) in the polyamide molding compound is in the range from 0 to 4 wt %, with respect to the sum of components (A) to (C).

9. The polyamide molding compound in accordance with claim 1, wherein functionalization of component (B) took place by copolymerization and the proportion of the compound utilized for the functionalization amounts to 3 to 25 wt %, with respect to the total mass of component (B); and/or functionalization of component (B) took place by grafting and the proportion of the compound utilized for the functionalization amounts to 0.3 to 2.5 wt %, with respect to the total mass of component (B).

10. The polyamide molding compound in accordance with claim 1, wherein the compound utilized for the functionalization of component (B) is selected from the group consisting of acrylic acid, methacrylic acid, glycidyl acrylic acid, glycidyl methacrylic acid, acrylic acid esters, methacrylic acid esters, -ethyl acrylic acid, maleic acid, maleic acid anhydride, fumaric acid, itaconic acid, itaconic acid anhydride, citraconic acid, aconitic acid, tetrahydrophthalic acid, butenyl succinic acid, and mixtures thereof.

11. The polyamide molding compound in accordance with claim 1, wherein monomers Ba), Bb), and Bc) are included in component (B) in the following molar proportions: Ba) 65 to 90 mol %; Bb) 8 to 33 mol %; Bc) 2 to 25 mol %; wherein the molar proportions of the monomers Ba), Bb), and Bc) add up to 100 mol %.

12. The polyamide molding compound in accordance with claim 1, wherein the at least one additive (C) is selected from the group consisting of inorganic stabilizers, organic stabilizers, lubricants, colorants, markers, inorganic pigments, organic pigments, demolding agents, chain-extending additives, anti-blocking agents, optical brighteners, and mixtures thereof.

13. The polyamide molding compound in accordance with claim 12, wherein the organic stabilizers are selected from antioxidants, antioozonants, light protection agents, and combinations thereof.

14. The polyamide molding compound in accordance with claim 1, wherein the modulus of elasticity determined in accordance with DIN EN ISO 527 (1997) amounts to at least 2100 MPa.

15. A molded body comprising a polyamide molding compound in accordance with claim 1.

16. The molded body in accordance with claim 15, wherein the molded body is selected from the group consisting of trim elements in an automobile interior or in the fashion area, sports articles, midsoles for sports shoes, leisure articles, toys, domestic articles, components of eyeglasses, furniture fittings, inserted soles, construction parts and visible parts for units in the sanitary area, hygiene area, and cosmetic area, parts of safety shoes, caps, housings, housing parts for electric devices and electronic devices, protective cases for cellular phones, visible parts in the area of computers and telecommunications, tubes, hoses, and components of E-cigarettes.

17. A polyamide molding compound comprising the following components: (A) 84.5 to 97.0 wt % of at least one amorphous or microcrystalline copolyamide selected from the group consisting of PA 6I/6T/MACMI/MACMT/PACMI/PACMT/Y, PA 6I/6T/MACMI/MACMT/Y, and mixtures thereof, wherein monomer Y has 7 to 14 carbon atoms and is selected from the group consisting of lactams, w-amino acids, and mixtures thereof; (B) 3.0 to 9.5 wt % of at least one functionalized impact resistance modifier comprising monomers Ba) ethylene; Bb) propylene; and Bc) 1-butene, wherein functionalization took place by copolymerization and/or by grafting with a compound selected from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic acid derivatives, unsaturated glycidyl compounds, and mixtures thereof; and (C) 0 to 6 wt % of at least one additive selected from the group consisting of inorganic stabilizers, lubricants, colorants, markers, inorganic pigments, organic pigments, demolding agents, chain-extending additives, anti-blocking agents, optical brighteners, and mixtures thereof; wherein the weight proportions of components (A) to (C) add up to 100 wt %; wherein the polyamide molding compound has a gloss of at least 75% at an angle of 60 as determined in accordance with DIN EN ISO 2813 (2015) after treatment of a test specimen of the polyamide molding compound with a soap solution and wherein the polyamide molding compound has a notch impact resistance of at least 70 kJ/m.sup.2 as determined in accordance with DIN EN ISO 179/2 eA.

Description

1 Measurement Methods

(1) The following measurement methods were used within the framework of this application.

(2) Relative Viscosity

(3) The relative viscosity was determined in accordance with ISO 307 (2007) at 20 C. 0.5 g polymer pellets were weighed into 100 ml m-cresol for this purpose; the calculation of the relative viscosity (RV) after RV=t/t.sub.0 took place on the basis of the section 11 of the standard.

(4) Glass Transition Temperature (Tg)

(5) The determination of the glass transition temperature took place by means of differential scanning calorimetry (DSC) in accordance with ISO 11357-2 and -3 (2013) at pellets having a water content of below 0.1 wt %. The DSC was performed in each of the two heating steps at a heating rate of 20 K/min. The sample was quenched in dry ice after the first heating. The glass transition temperature (Tg) was determined in the second heating step. The center of the glass transition zone, that was here specified as the glass transition temperature (Tg), was determined using the half height method.

(6) Modulus of Elasticity

(7) The determination of the modulus of elasticity and of the tensile strength was carried out in accordance with DIN EN ISO 527 (1997) at 23 C. at a tensile speed of 1 mm/min at an

(8) ISO tensile rod (type A1, mass 17020/104) manufactured in accordance with the standard: ISO/CD 3167 (2003).

(9) Notch Impact Resistance According to Charpy

(10) The determination of the notch impact resistance according to Charpy was carried out in accordance with ISO 179/2 eA (2000) at 23 C. at an ISO test rod, Type B1 (mass 80104 mm), manufactured in accordance with the standard ISO/CD 3167

(11) Gloss 60 and Gloss 60 after Washing Test

(12) The gloss at a measurement angle of 60 before and after the washing test was determined in accordance with DIN EN ISO 2813 (2015) on a Gloss Tector (ATP Messtechnik GmbH, Germany) at 23 C. at plates having the dimensions 60602 mm.

(13) Washing Test

(14) Five plates were immersed wholly or partially into a stirred soap bath thermostatted to 632 C. and left there for 302 min. After the removal, the still adhering soap solution was carefully wiped off using a white cotton cloth and the gloss 60 was determined at a point that had been immersed. The value specified in Tables 3 and 4 is the arithmetical mean of five measurements. The soap bath comprised distilled water and 0.1% triton x-100. Triton x-100 is a non-ionic surfactant of the Dow Chemical Company, USA (octylphenolethoxylate, CAS #9002-93-1).

(15) Manufacturing the Test Specimens

(16) The test specimens were manufactured on an injection molding machine of Arburg, model Allrounder 420 C 1000-250. Increasing cylinder temperatures from 280 C. to 300 C. were used here.

(17) The ISO tensile rods and ISO test rods were manufactured at a tool temperature of 80 C.

(18) The 60602 mm plates for the gloss measurement were manufactured at a tool temperature of 100 C. in a polished tool.

(19) The test specimens were used in the dry state if not otherwise specified; for this purpose, they were stored for at least 48 h at room temperature after the injection molding in a dry environment, i.e. over silica gel.

2 Starting Materials

(20) The materials used in the examples and in the comparison examples are collated in Tables 1 and 2.

(21) TABLE-US-00001 TABLE 1 Copolyamides (A1) to (A5) used in the examples and comparison examples. Components Description Manufacturer Polyamide (A1) Amorphous polyamide EMS-CHEMIE AG (in accordance with the 6I/6T/MACMI/MACMT/PACMI/PACMT/12 from 1,6- (Switzerland) invention) hexanediamine (39.0 mol %), bis(3-methyl-4- aminocyclohexyl)methane (7.1 mol %), bis(4- aminocyclohexl)methane (2.5 mol %), isophthalic acid (24.3 mol %), terephthalic acid (24.3 mol %), and lauric lactam (2.8 mol %). RV*: 1.60 Glass transition temperature: 159 C. Modulus of elasticity: 2800 MPa (dry, 23 C.) Notch impact resistance, Charpy: 11 kJ/m.sup.2 (dry, 23 C.) Polyamide (A2) Amorphous polyamide 6I/6T/MACMI/MACMT/12 EMS-CHEMIE AG (in accordance with the from 1,6-hexanediamine (39.0 mol %), bis(3-methyl-4- (Switzerland) invention) aminocyclohexyl)methane (9.6 mol %), isophthalic acid (24.3 mol %), terephthalic acid (24.3 mol %), and lauric lactam (2.8 mol %). RV*: 1.60 Glass transition temperature: 160 C. Modulus of elasticity: 2800 MPa (dry, 23 C.) Notch impact resistance, Charpy: 12 kJ/m2 (dry, 23 C.) Polyamide (A3) Amorphous polyamide 6I/6T from 1,6-hexanediamine EMS-CHEMIE AG (Comparison) (50 mol %), isophthalic acid (33.5 mol %), and (Switzerland) terephthalic acid (16.5 mol %) RV*: 1.54 Glass transition temperature: 125 C. Modulus of elasticity: 3000 MPa (dry, 23 C.) Notch impact resistance, Charpy: 8 kJ/m2 (dry, 23 C.) Polyamide (A4) Amorphous polyamide MACMI/MACMT/12 from EMS-CHEMIE AG (Comparison) bis(3-methyl-4-aminocyclohexyl)methane (38.0 (Switzerland) mol %), isophthalic acid (19.0 mol %), terephthalic acid (19.0 mol %), and lauric lactam (24.0 mol %) RV*: 1.54 Glass transition temperature: 194 C. Modulus of elasticity: 2200 MPa (dry, 23 C.) Notch impact resistance, Charpy: 10 kJ/m2 (dry, 23 C.) Polyamide (A5) Amorphous polyamide EMS-CHEMIE AG (Comparison) 612/6I/6T/MACM12/MACMI/MACMT from 1,6- (Switzerland) hexanediamine (31.5 mol %), bis(3-methyl-4- aminocyclohexyl)methane (18.5 mol %), isophthalic acid (15.5 mol %), terephthalic acid (15.5 mol %), and 1,12-dodecanoic acid (19.0 mol %) RV*: 1.74 Glass transition temperature: 145 C. Modulus of elasticity: 2300 MPa (dry, 23 C.) Notch impact resistance, Charpy: 11 kJ/m2 (dry, 23 C.) *Measured at a solution of 0.5 g polyamide in 100 ml m-cresol at 20 C.

(22) TABLE-US-00002 TABLE 2 Impact resistance modifiers (B1) to (B7) used in the examples and comparison examples. Impact resistance Blend of an ethylene/propylene copolymer (20 Mitsui Chemicals, modifier (B1) mol % propylene) and an ethylene/butene-1 Japan (in accordance with copolymer (15 mol % butene-1) in a weight ratio the invention) of 67:33 functionalized via grafting with 0.6 wt % maleic acid anhydride MVR** 1.3 cm.sup.3/10 min at 230 C. and 2.16 kg Trade name: Tafmer MC201 Impact resistance Functionalized copolymer of ethylene and 1- Du Pont de Nemours modifier (B2) octene (Deutschland) GmbH, (Comparison) Functionalized with 0.5 wt % maleic acid anhydride Germany Trade name: Fusabond N MN493D Impact resistance Functionalized copolymer of ethylene and but-1- Mitsui Chemicals, modifier (B3) ene Japan (Comparison) 1.0 wt % maleic acid anhydride Trade name: Tafmer MH7020 Impact resistance Copolymer of ethylene and glycidylmethacrylate Arkema GmbH, modifier (B4) having 8 wt % glycidylmethacrylate Germany (Comparison) Trade name: Lotader AX 8840 Impact resistance Functionalized styrene-ethylene/butene-1-styrene Kraton Polymers LLC, modifier (B5) block copolymer USA (Comparison) having 30 wt % styrene 1.7 wt % maleic acid anhydride Trade name: Kraton FG1901 GT Impact resistance Styrene-isobutene-styrene block copolymer Kaneka Belgium NV, modifier (B6) Trade name Sibstar 102 T Belgium (Comparison) Impact resistance Functionalized copolymer of ethylene and Rohm und Haas, USA modifier (B7) propene, grafted with maleic acid anhydride (Comparison) Trade name Paraloid EXL 3808 **Melt volume rate

3 Examples and Comparison Examples

3.1 General Manufacturing Rule for Copolyamides (A)

(23) The manufacture of copolyamides (A) takes place in a manner known per se in known, stirrable pressure autoclaves having a presentation vessel and a reaction vessel.

(24) Deionized water is presented in the presentation vessel and the monomers and possible additives are added. Inertization then takes place multiple times with nitrogen gas. Heating takes place to 180 to 230 C. while stirring at the pressure adopted to obtain a homogeneous solution. This solution is pumped through a screen into the reaction vessel and is there heated to the desired reaction temperature of 270 to 310 C. at a pressure of a maximum of 30 bar. The preparation is maintained at the reaction temperature for 2 to 4 hours in the pressure phase. In the subsequent expansion phase, the pressure is reduced to atmospheric pressure within 1 to 2.5 hours, with the temperature being able to fall a little. In the following degassing phase, the preparation is maintained at a temperature of 270 to 310 C. at atmospheric pressure for 1 to 2.5 hours. The polymer melt is discharged in strand form, cooled at 15 to 80 C. in the water bath, and pelletized. The pellets are dried at 80 to 120 C. under nitrogen or in vacuum to a water content of less than 0.1 wt %.

(25) Suitable catalysts for accelerating the polycondensation reaction are acids containing phosphorous such as H.sub.3PO.sub.2, H.sub.3PO.sub.3, H.sub.3PO.sub.4, their salts or organic derivatives. The catalysts are added in the range from 0.01 to 0.5 wt %, preferably 0.03 to 0.1 wt %, with respect to the copolyamide.

(26) Suitable anti-foaming agents for avoiding foam formation during the degassing are aqueous, 10% emulsions that contain silicons or silicon derivatives and that are used in quantities from 0.01 to 1.0 wt %, preferably 0.01 to 0.10 wt %, with respect to the copolyamide.

(27) The setting of the relative viscosity and thus of the molar mass can take place in a manner known per se, e.g. via monofunctional amines or carboxylic acids, and/or difunctional diamines or dicarboxylic acids as chain regulators. The chain regulators can be used individually or in combination. The typical quantity of use of the monofunctional chain regulators is 10 to 200 mmol per kg copolyamide.

3.2 General Manufacturing and Processing Rule for the Polyamide Molding Compounds

(28) To manufacture the polyamide molding compound in accordance with the invention, components A), B), and optionally C) are mixed on conventional compounding machines such as single shaft or twin shaft extruders or screw kneaders. The components are here metered individually via gravimetric metering trolleys into the feed or respectively into a side feeder or are supplied in the form of a dry blend.

(29) If additives (component C) are used, they can be introduced directly or in the form of a master batch. The carrier material of the master batch is preferably a polyamide or a polyolefin. From the polyamides, the polyamide of the respective components A is particularly suitable for this.

(30) The dried pellets of components A), B), and optionally C), are mixed in a closed container for the dry blend preparation. This mixture is homogenized by means of a wobble mixer, a tumble mixer, or a tumbler drier for 10 to 40 minutes. The homogenization can take place under a dried protective gas to avoid moisture absorption. The compounding takes place a set cylinder temperatures of 250 to 310 C., with the temperature of the first cylinder being able to be set to below 110 C. Degassing can take place in front of the nozzle. This can take place by means of a vacuum or atmospherically. The melt is discharged in strand form, cooled at 10 to 80 C. in the water bath, and subsequently pelletized. The pellets are dried at 80 to 120 C. under nitrogen or in vacuum to a water content of less than 0.1 wt %.

(31) The processing of the polyamide molding compounds in accordance with the invention in injection molding takes place at increasing cylinder temperatures of 260 to 310 C., with a temperature profile being able to be used that increases and decreases from the feed to the nozzle. The tool temperature is set to a temperature of 60 to 140 C., preferably 70 to 120 C.

3.1 Manufacture of the Polyamide Molding Compound in Accordance with Example 1

(32) The dried pellets (A) and (B) were mixed to form a dry blend, and indeed in the ratio indicated in Table 3. This mixture was homogenized by means of a tumble mixer for approximately 20 minutes.

(33) The polyamide molding compound was manufactured on a twin-shaft extruder of Werner & Pfleiderer type ZSK 25. The dry blend was here metered into the feed via a metering scale.

(34) The temperature of the first housing was set to 100 C.; that of the remaining housings to 260 to 290 C. A speed of 150 r.p.m. and a throughput of 10 kg/h were used and no degassing took place. The melt strand was cooled in the water bath, cut, and the pellets obtained were dried at 100 C. in a vacuum (30 mbar) for 24 h to a water content of less than 0.1 wt %.

(35) 3.4 Examples and comparison examples

(36) The results of the examples and comparison examples in accordance with the present invention are compiled in the following Tables 3 and 4.

(37) TABLE-US-00003 TABLE 3 Examples and comparison examples. Examples Comparison examples Unit 1 2 3 4 5 6 7 8 9 Components Polyamide Wt % 95 92.5 97.5 90 97.5 95 92.5 90 (A1) Polyamide Wt % 95 (A2) Impact Wt % 5 7.5 5.0 2.5 10 resistance modifier (B1) Impact Wt % 2.5 5 7.5 10 resistance modifier (B2) Tests Modulus of MPa 2400 2300 2400 2600 2200 2600 2500 2300 2300 elasticity Notch impact kJ/m.sup.2 85 93 82 21 93 22 86 95 96 resistance, Charpy 23 C. Gloss 60 % 98 94 95 100 93 100 88 84 76 Gloss 60 % 87 83 86 97 65 95 69 53 13 after washing

(38) TABLE-US-00004 TABLE 4 Comparison examples Comparison examples Unit 10 11 12 13 14 15 16 17 Components Polyamide (A1) Wt % 92.5 92.5 92.5 92.5 92.5 Polyamide (A3) Wt % 95 Polyamide (A4) Wt % 95 Polyamide (A5) Wt % 92.5 Impact resistance Wt % 5 5 7.5 modifier (B1) Impact resistance Wt % 7.5 modifier (B3) Impact resistance Wt % 7.5 modifier (B4) Impact resistance Wt % 7.5 modifier (B5) Impact resistance Wt % 7.5 modifier (B6) Impact resistance Wt % 7.5 modifier (B7) Tests Modulus of elasticity MPa 2600 1900 1900 2100 2300 2300 2400 2000 Notch impact kJ/m.sup.2 17 21 74 79 65 80 16 81 resistance, Charpy 23 C. Gloss 60 % 95 98 88 82 84 74 100 88 Gloss 60 after % 41 53 46 11 21 14 98 11 washing

4 Discussion of the Results

(39) The polyamide molding compounds in accordance with Examples 1 to 3 comprise a copolyamide in accordance with the invention and 5 to 7.5 wt % of an impact resistance modifier in accordance with the invention. Molded bodies from these polyamide molding compounds have very high values for gloss at 60 after the washing test and the notch impact resistance is likewise very high.

(40) The polyamide molding compounds in accordance with comparison examples VB4 and VB5 differ from the examples in accordance with the invention in that a lower or higher proportion of the same impact resistance modifier was used. A considerable drop in the notch impact resistance is observed for a lower proportion of impact resistance modifier, whereas a significantly worse gloss is observed after the washing test for a higher proportion of the impact resistance modifier.

(41) In comparison examples VB6 to VB9, 2.5 to 10 wt % of an impact resistance modifier not in accordance with the invention was used. Good gloss after the washing test and good values for the notch impact resistance were not observed for any of the corresponding polyamide molding compounds. It is noticeable that a considerable degradation of the gloss is also observed after the washing test with the proportion of impact resistance modifier in accordance with the invention that was used in comparison examples VB7 and VB8.

(42) The polyamide molding compounds in accordance with comparison examples VB10 to VB12 comprise an impact resistance modifier in accordance with the invention in the quantities in accordance with the claims. However, these polyamide molding compounds comprise a copolyamide not in accordance with the invention. The gloss after the washing test and the notch impact resistance in accordance with these comparison examples are much worse than for examples B1 to B3 in accordance with the invention.

(43) Impact resistance modifiers not in accordance with the invention and the polyamide (A1) in accordance with the invention were used in the comparison examples VB13 to VB 17. The desired combination of the properties good gloss after the washing test and good notch impact resistance was not observed for any of these comparison examples.

(44) The polyamide molding compounds in accordance with comparison examples VB11, VB12, and VB17 additionally demonstrate too small a modulus of elasticity.

(45) Surprisingly, achieving both a good gloss at 60 after washing and a good notch impact resistance is only successful by the combination of features in accordance with the invention described herein.