Reinforced polyamide molding compounds having low haze and molded bodies therefrom

Abstract

The present invention relates to a polyamide molding compound comprising the following components or consisting of these components: (A) 50 to 95 wt % of a mixture comprising the specific polyamides (A1) and (A2); (B) 5 to 50 wt % of at least one glass filler having a refractive index in the range from 1.540 to 1.600; (C) 0 to 10 wt % of at least one additive; wherein the weight proportions of the components (A) to (C) add up to 100% by weight; wherein the content of (A1) in the mixture (A) is >50 wt %, if the ratio is 2/1>1 and the content of (A2) in the mixture (A) is >50 wt %, if the ratio is 2/11, where 1=n(A1)n(B) applies and 2=n(B)n(A2) applies; wherein the transparent polyamides (A1) and (A2) have a transparency of at least 90% and a haze of at most 3%; and wherein the mixture (A) has a transparency of at least 88% and a haze of at most 5%. The present invention additionally relates to molded bodies composed of these polyamide molding compounds.

Claims

1. A polyamide molding compound comprising the following components: (A) 50 to 95 wt % of a mixture consisting of the polyamides (A1) and (A2), wherein (A1) is at least one transparent, semi-aromatic polyamide having more than 35 mol % of monomers having aromatic structural units, related to the total quantity of diamines and dicarboxylic acids in the polyamide (A1) that is amorphous or microcrystalline; and (A2) is at least one transparent, semi-aromatic polyamide having at most 35 mol % of monomers having aromatic structural units, related to the total quantity of diamines and dicarboxylic acids in the polyamide (A2) that is amorphous or microcrystalline; (B) 5 to 50 wt % of at least one glass filler having a refractive index in the range from 1.540 to 1.600; and (C) 0 to 10 wt % of at least one additive; wherein the weight proportions of the components (A) to (C) add up to 100% by weight; wherein the content of (A1) in the mixture (A) is >50 wt %, if the ratio is 2/1>1 and the content of (A2) in the mixture (A) is >50 wt %, if the ratio is 2/11, where 1=n(A1)n(B) and 2=n(B)n(A2) applies; n being the refractive index measured according to ISO 489 (1999 April), wherein the polyamide molding compound has a transparency of at least 80% and a haze of maximum 40%; wherein the transparency and haze of the polyamide molding compound are measured in accordance with ASTM D1003 on a molded plate of the polyamide molding compound having a dimension of 60 mm60 mm2 mm.

2. The polyamide molding compound in accordance with claim 1, wherein the polyamide mixture (A) comprises 51 to 95 wt of polyamide (A1) and 5 to 49 wt % of polyamide (A2) if 2/1>1; or the polyamide mixture (A) comprises 51 to 95 wt % of polyamide (A2) and 5 to 49 wt % of polyamide (A2) if 2/11.

3. The polyamide molding compound in accordance with claim 1, wherein the transparent polyamides (A1) are made up of the following monomers: (a-A1) 10 to 100 mol % of cycloaliphatic diamines, with respect to the total quantity of diamines; (b-A1) 0 to 90 mol % of diamines having aromatic structural units, with respect to the total quantity of diamines; (c-A1) 0 to 90 mol % of open-chain cycloaliphatic diamines, with respect to the total quantity of diamines; (d-A1) 0 to 65 mol % of open-chain aliphatic dicarboxylic acids, with respect to the total quantity of dicarboxylic acids; (e-A1) 35 to 100 mol % of aromatic dicarboxylic acids, with respect to the total quantity of dicarboxylic acids; (f-A1) 0 to 65 mol % of cycloaliphatic dicarboxylic acids, with respect to the total quantity of dicarboxylic acids; and (g-A1) 0 to 40 wt % of lactams and/or aminocarboxylic acids having 6 to 12 carbon atoms, with respect to the total quantity of the monomers (a-A1) to (g-A1), where the sum of the diamines (a-A1), (b-A1), and (c-A1) produces 100 mol %; where the sum of the dicarboxylic acids (d-A1), (e-A1), and (f-A1) produces 100 mol %; and where the sum of the monomers (b-A1) and (e-A1) amounts to more than 35 mol %, with respect to the sum of the total diamines and of the total dicarboxylic acids in the polyamide (A1).

4. The polyamide molding compound in accordance with claim 1, wherein the transparent polyamide (A1) comprises at least 36 mol % of monomers having aromatic structural units, with respect to the total quantity of diamines and dicarboxylic acids in the polyamide (A1).

5. The polyamide molding compound in accordance with claim 1, wherein the transparent polyamides (A2) are made up of the following monomers: (a-A2) 20 to 100 mol % of cycloaliphatic diamines, with respect to the total quantity of diamines; (b-A2) 0 to 70 mol % of diamines having aromatic structural units, with respect to the total quantity of diamines; (c-A2) 0 to 80 mol % of open-chain aliphatic diamines, with respect to the total quantity of diamines; (d-A2) 20 to 100 mol % of open-chain aliphatic dicarboxylic acids, with respect to the total quantity of dicarboxylic acids; (e-A2) 0 to 70 mol % of aromatic dicarboxylic acids, with respect to the total quantity of dicarboxylic acids; (f-A2) 0 to 70 mol % of cycloaliphatic dicarboxylic acids, with respect to the total quantity of dicarboxylic acids; and (g-A2) 0 to 40 wt % of lactams and/or aminocarboxylic acids having 6 to 12 carbon atoms, with respect to the total quantity of the monomers (a-A2) to (g-A2), where the sum of the diamines (a-A2), (b-A2), and (c-A2) produces 100 mol %; where the sum of the dicarboxylic acids (d-A2), (e-A2), and (f-A2) produces 100 mol %; and where the sum of the monomers (b-A2) and (e-A2) amounts to at most 35 mol %, with respect to the sum of the total diamines and of the total dicarboxylic acids in the polyamide (A2).

6. The polyamide molding compound in accordance with claim 1, wherein the transparent polyamide (A2) comprises at most 33 mol % of monomers having aromatic structural units, with respect to the total quantity of diamines and dicarboxylic acids in the polyamide (A2).

7. The polyamide molding compound in accordance with claim 1, wherein the monomers having aromatic structural units for the transparent polyamides (A1) and (A2) are selected from the group consisting of terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid (NDA), biphenyldicarboxylic acid, 4,4-diphenyl ether dicarboxylic acid, 4,4-diphenylmethanedicarboxylic acid, 4,4-diphenylsulfonedicarboxylic acid, 1,5-anthracene dicarboxylic acid, p-terphenylene-4,4-dicarboxylic acid, 2,5-pyridine dicarboxylic acid, xylylenediamine, and mixtures thereof.

8. The polyamide molding compound in accordance with claim 1, wherein the transparency of the molded plate is at least 85%; and/or the haze of the molded plate amounts to a maximum of 35%; and/or the molded plate produced from the polyamide molding compound, wherein the glass filler is in the form of glass fibers, has an arithmetical mean roughness Ra determined in accordance with DIN EN ISO 4287 (2010 July) by means of a MarSurf XR1 Surface Measuring Station of at most 0.12 m, and/or has a surface roughness R.sub.z of at most 1.50 m.

9. The polyamide molding compound in accordance with claim 3, wherein the cycloaliphatic diamine (a-A1) is selected from the group consisting of bis(4-amino-3-methylcyclohexyl)methane, bis-(4-aminocyclohexyl)methane, bis-(4-amino-3-ethylcyclohexyl)methane, bis-(4-amino-3,5-dimethylcyclohexyl)methane, 2,6-norbornane diamine, 1,3-diaminocyclohexane, 1,4-diaminocyclohexanediamine, isophorone diamine, 1,3-bis-(aminomethyl)cyclohexane, 1,4-bis-(aminomethyl)cyclohexane, 2,2-(4,4-diaminodicyclohexyl)propane, and mixtures thereof; and/or the aromatic diamine (b-A1) is selected from xylylenediamines; and/or the diamine (c-A1) is selected from the group consisting of 1,4-butanediamine, 1,5-pentanediamine, 2-methyl-1,5-pentanediamine, hexanediamines, 2,2,4-trimethyl-1,6-hexamethylenediamine, 2,4,4-trimethyl-1,6-hexamethylenediamine, nonanediamines, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,13-trideceanediamine, 1,14-tetradecanediamine, 1,18-octadecanediamine, and mixtures thereof; and/or the aliphatic dicarboxylic acid (d-A1) is selected from the group consisting of 1,6-apidic acid, 1,9-nonanedioic acid, 1,10-decanedioic acid, 1,11-undecanedioic acid, 1,12 dodecanedioic acid, 1,13-tricanedioic acid, 1,14-tetradecanedioic acid, 1,16-hexadecanedioic acid, 1,18-octadecanedioic acid, and mixtures thereof; and/or the aromatic dicarboxylic acid (e-A1) is selected from the group consisting of terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid (NDA), biphenyldicarboxylic acid, 4,4-diphenyl ether dicarboxylic acid, 4,4-diphenylmethanedicarboxylic acid, and 4,4-diphenylsulfonedicarboxylic acid, 1,5-anthracene dicarboxylic acid, p-terphenylene-4,4-dicarboxylic acid, and 2,5-pyridinedicarboxylic acid, and mixtures thereof; and/or the cycloaliphatic dicarboxylic acid (f-A1) is selected from the group consisting of 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2,3-norbornanedicarboxylic acid, 2,6-norbornanedicarboxylic acid, and mixtures thereof; and/or the lactam and/or the ,-aminocarboxylic acid (g-A1) is selected from the group consisting of m-aminobenzoic acid, p-aminobenzoic acid, caprolactam (CL), ,-aminocaproic acid, ,-aminoheptanoic acid, ,-aminooctanoic acid, ,-aminononanoic acid, ,-aminodecanoic acid, ,-aminoundecanoic acid (AUA), laurolactam (LL), and ,-aminododecanoic acid (ADA).

10. The polyamide molding compound in accordance with claim 1, wherein the polyamide (A1) is selected from the group consisting of PA MACMI/12, PA MACMI/1012, PA MACMT/12, PA MACMI/MACMT/12, PA MACMI/MACMT, PA MACMI/MACMT/MACM12, PA 6I/6T/MACMI/MACMT, PA 6I/6T/MACMI/MACMT/12, PA 6I/MACMI, PA 6I/6T/PACMI/PACMT, PA 6I/612/MACMI/MACM12, PA 6T/612/MACMT/MACM12, PA 6I/6T/612/MACMI/MACMT/MACM12, PA 6I/6T/MACMI/MACMT/PACMI/PACMT, PA 6I/6T/MACMI/MACMT/PACMI/PACMT/12, PA MACMI/MACMT/MACM36, PA MACMI/MACM36, PA MACMT/MACM36, PA 12/PACMI, PA 12/MACMT, PA 6/PACMT, PA 6/PACMI, PA MXDI, PA MXDI/MXD6, PA MXDI/MXD10, PA MXDI/MXDT, PA MXDI/MACMI, PA MXDI/MXDT/MACMI/MACMT, PA 6I/6T/BACI/BACT, PA MACMI/MACMT/BACI/BACT, PA 6I/6T/MACMI/MACMT/BACI/BACT and mixtures thereof, wherein these polyamides comprise more than 35 mol % of monomers having aromatic structural units, with respect to the total quantity of diamines and dicarboxylic acids; and/or the polyamide (A2) is selected from the group consisting of PA MACM9, PA MACM10, PA MACM11, PA MACM12, PA MACM13, PA MACM14, PA MACM15, PA MACM16, PA MACM17, PA MACM18, PA MACM36, PA PACM9, PA PACM10, PA PACM11, PA PACM12, PA PACM13, PA PACM14, PACM15, PA PACM16, PACM17, PA PACM18, PA PACM36, PA TMDC9, PA TMDC10, PA TMDC11, PA TMDC12, PA TMDC13, PA TMDC14, PA TMDC15, PA TMDC16, PA TMDC17, PA TMDC18, PA TMDC36 or copolyamides PA MACM10/1010, PA MACM10/PACM10, PA MACM12/1012, PA MACM14/1014, PA PACM10/1010, PA PACM12/1012, PA PACM14/1014, PA MACM12/PACM12, PA MACM14/PACM14, PA MACMI/MACMT/MACM12, PA 6I/612/MACMI/MACM12, PA 6T/612/MACMT/MACM12, PA 6I/6T/612/MACMI/MACMT/MACM12, PA MACMI/MACMT/MACM36, PA MACMI/MACM36, PA MACMT/MACM36, PA MACMI/MACM12, PA MACMT/MACM12, PA MACMI/MACMT/10I/10T/1012, PA 6I/6T/612/PACMI/PACMT/PACM12, PA 6I/612/MACMI/MACM12, PA 6T/612/MACMT/MACM12, PA 10T/1012/MACMT/MACM12, PA 10I/1012/MACMI/MACM12, PA6I/6T/MACMI/MACMT/PACMI/PACMT/MACM12/PACM12, PA MACMI/PACMI/MACM12/PACM12, PA MACMT/PACMT/MACM12/PACM12, PA MACMI/PACMT/MACM12/PACM12, PA MACMI/MACM36, PA MACMI/MACMT/MaCM36, PA 1012/MACMI, PA 1012/MACMT, 1010/MACMI, PA 1010/MACMT, PA 612/MACMT, PA 610/MACMT, PA 612/MACMI, PA 610/MACMI, PA 1012/PACMI, PA 1012/PACMT, PA 1010/PACMI, PA 1010/PACMT, PA 612/PACMT, PA 612/PACMI, PA 610/PACMT, PA 610/PACMI and mixtures thereof; wherein these polyamides have at most 35 mol % of monomers having aromatic structural units, with respect to the total quantity of diamines and dicarboxylic acids.

11. The polyamide molding compound in accordance with claim 1, wherein the at least one glass filler (B) is selected from the group consisting of glass fibers, ground glass fibers, glass particles, glass flakes, glass spheres, hollow glass spheres, and combinations thereof.

12. The polyamide molding compound in accordance with claim 1, wherein the glass type of the at least one glass filler (B) is selected from the group consisting of E-glass, E-CR-glass, R-glass, AR-glass, and mixtures of glass having substantially the same refractive index.

13. The polyamide molding compound in accordance with claim 1, wherein the at least one additive (C) is selected from the group consisting of inorganic and organic stabilizers, monomers, plasticizers, less than 5 wt % with respect to the total mass of the polyamide molding compound of semi-crystalline polyamides, impact modifiers, lubricants, colorants, marking means, photochromic agents, demolding means, condensation catalysts, chain regulators, anti-foaming agents, anti-blocking agents, optical brighteners, non-halogen flame retardants, natural sheet silicates, synthetic sheet silicates, nanoscale fillers having a particle size of a maximum of 100 nm, and mixtures thereof.

14. 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 55 to 90 wt % with respect to the sum of the components (A) to (C); and/or the proportion of component (B) in the polyamide molding compound is in the range from 10 to 40 wt % with respect to the sum of the components (A) to (C); and/or the proportion of component (C) in the molding compound is in the range from 0 to 7 wt % with respect to the sum of the components (A) to (C); and/or the polyamide molding compound does not contain any other components than components (A) to (C).

15. The polyamide molding compound in accordance with claim 1, wherein component (A1) has a glass transition temperature determined in accordance with ISO 11357-2 of at least 135 C.; and/or component (A2) has a glass transition temperature determined in accordance with ISO 11357-2 of at least 135 C.; and/or mixture (A) has a glass transition temperature determined in accordance with ISO 11357-2 of at least 130 C.; and/or the polyamide molding compound has a glass transition temperature determined in accordance with ISO 11357-2 of at least 130 C.

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

17. The molded body in accordance with claim 16, which is a multilayer molded body.

18. The polyamide molding compound in accordance with claim 5, wherein the cycloaliphatic diamine (a-A2) is selected from the group consisting of bis(4-amino-3-methylcyclohexyl)methane, bis-(4-aminocyclohexyl)methane, bis-(4-amino-3-ethylcyclohexyl)methane, bis-(4-amino-3,5-dimethylcyclohexyl)methane, 2,6-norbornane diamine, 1,3-diaminocyclohexane, 1,4-diaminocyclohexanediamine, isophorone diamine, 1,3-bis-(aminomethyl)cyclohexane, 1,4-bis-(aminomethyl)cyclohexane, 2,2-(4,4-diaminodicyclohexyl)propane, and mixtures thereof; and/or the aromatic diamine (b-A2) is selected from xylylenediamines; and/or the diamine (c-A2) is selected from the group consisting of 1,4-butanediamine, 1,5-pentanediamine, 2-methyl-1,5-pentanediamine, hexanediamines, 2,2,4-trimethyl-1,6-hexamethylenediamine, 2,4,4-trimethyl-1,6-hexamethylenediamine, nonanediamines, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,13-trideceanediamine, 1,14-tetradecanediamine, 1,18-octadecanediamine, and mixtures thereof; and/or the aliphatic dicarboxylic acid (d-A2) is selected from the group consisting of 1,6-apidic acid, 1,9-nonanedioic acid, 1,10-decanedioic acid, 1,11-undecanedioic acid, 1,12 dodecanedioic acid, 1,13-tricanedioic acid, 1,14-tetradecanedioic acid, 1,16-hexadecanedioic acid, 1,18-octadecanedioic acid, and mixtures thereof; and/or the aromatic dicarboxylic acid (e-A2) is selected from the group consisting of terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid (NDA), biphenyldicarboxylic acid, 4,4-diphenyl ether dicarboxylic acid, 4,4-diphenylmethanedicarboxylic acid, and 4,4-diphenylsulfonedicarboxylic acid, 1,5-anthracene dicarboxylic acid, p-terphenylene-4,4-dicarboxylic acid, and 2,5-pyridinedicarboxylic acid, and mixtures thereof; and/or the cycloaliphatic dicarboxylic acid (f-A2) is selected from the group consisting of 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2,3-norbornanedicarboxylic acid, 2,6-norbornanedicarboxylic acid, and mixtures thereof; and/or the lactam and/or the ,-aminocarboxylic acids (g-A2) are/is selected from the group consisting of m-aminobenzoic acid, p-aminobenzoic acid, caprolactam (CL), ,-aminocaproic acid, ,-aminoheptanoic acid, ,-aminooctanoic acid, ,-aminononanoic acid, ,-aminodecanoic acid, ,-aminoundecanoic acid (AUA), laurolactam (LL), and ,-aminododecanoic acid (ADA).

19. The polyamide molding compound of claim 10, wherein the polyamide mixture (A) comprises the following combination of polyamide (A1) and polyamide (A2): polyamide (A1) 6I/6T/612/MACMI/MACMT/MACM12 and polyamide (A2) 6I/6T/612/MACMI/MACMT/MACM12; polyamide (A1) 6I/6T/MACMI/MACMT and polyamide (A2) 6I/6T/612/MACMI/MACMT/MACM12; polyamide (A1) 6I/6T/612/MACMI/MACMT/MACM12 and polyamide (A2) MACMI/MACMT/12; polyamide (A1) 6I/6T/612/MACMI/MACMT/12/PACMI/PACMT and polyamide (A2) MACMI/MACMT/MACM12; polyamide (A1) 6I/6T/MACMI/MACMT and polyamide (A2) MACMI/12; or polyamide (A1) 6I/6T/612/MACMI/MACMT/MACM12 and polyamide (A2) MACMI/12.

Description

1 MEASUREMENT METHODS

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

(2) Surface roughness, R.sub.a, R.sub.z

(3) The roughness of the test specimens was measured in accordance with DIN EN ISO 4287 (2010 July) using a MarSurf XR1 Surface Measuring Station of Mahr GmbH (DE). The roughness values, that is, the arithmetical mean roughness Ra and the surface roughness R.sub.z, are given in micrometers (m).

(4) Haze, Transparency

(5) The transparency and haze were measured in accordance with ASTM D1003 on a measuring device Haze Gard Plus of BYK Garder at plates of 2 mm thickness (60 mm60 mm surface) with CIE light type C at 23 C. The surface of the specimen (plate 60602 mm) had an arithmetical mean roughness R.sub.a and a surface roughness R.sub.z as explicitly specified for the molding compounds in accordance with the examples and comparison examples in Table 2 or for the multilayer molded body. The manufacture of the test specimens will be described under item 3.3.

(6) Melting Point (T.sub.m) and Enthalpy of Fusion (H.sub.m)

(7) The melting point and the enthalpy of fusion were determined in accordance with ISO 11357-3 (2013) on pellets. The DSC (differential scanning calorimetry) measurements were performed at a heating rate of 20 K/min.

(8) Glass Transition Temperature, T.sub.g

(9) The determination of the glass transition temperature T.sub.g took place in accordance with ISO 11357-2 (2013) at pellets by means of differential scanning calorimetry (DSC). It 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 (T.sub.g) was determined in the second heating step. The center of the glass transition zone, that was here specified as the glass transition temperature, was determined using the half height method.

(10) Relative viscosity, .sub.rel

(11) The relative viscosity was determined in accordance with IS 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.

(12) Modulus of Elasticity

(13) The determination of the modulus of elasticity and of the tensile strength was carried out in accordance with ISO 527 (2012) at 23 C. at a tensile speed of 1 mm/min at an ISO tensile rod (type A1, mass 17020/104) manufactured in accordance with the standard: ISO/CD 3167 (2003).

(14) Failure Stress and Elongation at Break

(15) The determination of the failure stress and of the elongation at break was carried out in accordance with ISO 527 (2012) at 23 C. at a tensile speed of 5 mm/min at an ISO tensile rod (type A1, mass 17020/104) manufactured in accordance with the standard ISO/CD 3167 (2003).

(16) Impact Resistance According to Charpy

(17) The determination of the impact resistance according to Charpy was carried out in accordance with ISO 179/2*eU (1997, *2=instrumented) at 23 C. at an ISO test rod, Type B1 (mass 80104 mm), manufactured in accordance with the standard ISO/CD 3167 (2003).

(18) Notch Impact Resistance According to Charpy

(19) The determination of the notch impact resistance was carried out according to Charpy in accordance with ISO 179/2*eA (1997, *2=instrumented) at 23 C. at an ISO test rod, Type B1 (mass 80104 mm), manufactured in accordance with the standard ISO/CD 3167 (2003).

(20) Heat Deflection Temperature (HDT)

(21) The heat deflection temperature (HDT) or also deformation temperature under load is reported as HDT/A and/or HDT/B. HDT/A corresponds to method A having a bending stress of 1.80 MPa and HDT/B corresponds to method B having a bending stress of 0.45 MPa. The HDT values were determined in accordance with ISO 75 (2013 April) at ISO baffle rods with the dimensions 80104 mm.

(22) Measuring the Refractive Index of Glass Fibers

(23) The determination of the refractive index of glass fibers took place using the Beck's line method and using immersion fluids with respect to 589 nm based on method B of ISO 489 (1999 April).

(24) Measuring the Refractive Index of Polyamides

(25) The refractive index of the polyamides A1 and A2 was determined in accordance with ISO 489 (1999 April) at plates of 2 mm thickness (60602 mm) at a wavelength of 589 nm and at a temperature of 23 C. by means of an Abbe refractometer of Carl Zeiss (method A). 1-1-bromonaphthalene was applied as the contact fluid between the examined plate and the prism surface.

2 STARTING MATERIALS

(26) The materials used in the examples and in the comparison examples are collated in Table 1.

(27) TABLE-US-00003 TABLE 1 Materials used in the examples and in the comparison examples Components Description Manufacturer Polyamide 1 PA 6I/MACMI/6T/MACMT (77/13/8/2) EMS-CHEMIE AG Component (A1) Rel. viscosity = 1.42 (Switzerland) Aromatic structural units: 50 mol % Refractive index: 1.582 Transparency: 93%; Haze: 0.5% Tg: 147 C. Polyamide 2 PA 6I/6T/612/MACMI/MACMT/MACM12 EMS-CHEMIE AG Component (A1) (28/28/19/9/9/7) (Switzerland) Rel. viscosity = 1.73 Aromatic structural units: 37 mol % Refractive index: 1.559 Transparency: 93%; Haze: 0.6% Tg: 140 C. Polyamide 3 PA 6I/6T/612/MACMI/MACMT/MACM12 EMS-CHEMIE AG Component (A2) (20/20/24/11/11/14) (Switzerland) Rel. viscosity = 1.74 Aromatic structural units: 31 mol % Refractive index: 1.548 Transparency: 93%; Haze: 0.6% Tg: 144 C. PA 6/12 PA 6/12 (90/10) EMS-CHEMIE AG Rel. viscosity = 1.81 (Switzerland) Glass fiber ECS 301T-3 CPIC (China) Refractive index: 1.556

3 EXAMPLES AND COMPARISON EXAMPLES

3.1 Manufacturing the Polyamide Molding Compounds

(28) The compounds are generally mixed (compounded) on standard compounding machines such as single-shaft or twin-shaft extruders or screw kneaders in the polymer melt to manufacture the plastic molding compound. The components are here individually metered into the feeder or are supplied in the form of a dry blend. If additives are used, they can be introduced directly or in the form of a master batch. In a dry blend manufacture, the dried polymer pellets and the additives are mixed. The mixing can take place under a dried protective gas to avoid moisture absorption. The glass fibers used are metered into the polymer melt in the intended ratio via a side feeder and are further homogenized in the cylinder of the compounding machine. The metering of all the components into the feeder or side feeder are set via electronically controlled scales such that the desired quantity ratios of glass-polymer result therefrom.

(29) The compounding takes place at set extruder cylinder temperatures of e.g. 230 C. to 350 C. Vacuum can be applied or atmospheric degassing can take place in front of the nozzle. The melt is output into a water bath in extruded form and is pelletized. An underwater pelletization or a strand pelletization is preferably used for pelletization.

(30) The plastic molding compound thus preferably obtained in pellet form is subsequently dried and can then be further processed to molded bodies by injection molding. This takes place via a repeat melting of the dry pellets in a heatable cylinder and conveying the melt into an injection mold in which the melt can solidify.

3.2 Manufacture of the Polyamide Molding Compound in Accordance with Examples B1 to B3

(31) The molding compounds for the examples B1 to B3 and for the comparison examples VB1 to VB3 were manufactured on a twin shaft extruder of the company Werner and Pfleiderer, Type ZSK25. The polyamides (A1) and (A2) were metered into the feed of the extruder via metering trolleys in the quantity portions specified in Table 2. The glass fibers used were conveyed into the polymer melt in the intended ratio via a side feeder and were further homogenized in the cylinder of the compounding machine.

(32) The temperature of the first housing was set to 80 C.; that of the remaining housings in an increasing manner from 270 to 300 C. A speed of 200 r.p.m. and a throughput of 15 kg/h was used and degassing took place in the third zone in front of the nozzle in the nitrogen stream. The polyamide molding compound output as a strand was cooled in a water bath at 80 C. and pelletized, and the obtained pellets were dried at 90 C. in vacuum at 30 mbar to a water content of below 0.1 wt %.

3.3 Manufacture of the Test Specimens

(33) Tensile rods, baffle rods, and plates were injected from the pellets obtained as test specimens at which the properties specified in Table 2 were determined. The test specimens were manufactured on an injection molding machine of Arburg, model Allrounder 420 C 1000-250. Increasing cylinder temperatures from 250 C. to 290 C. were used here. The melt temperature for all the injected molded bodies amounted to 294-300 C. in each case. The tool temperature was at 120 C. in each case in the case of plates (2 mm60 mm60 mm). The tool temperatures of the tensile rods and of the baffle rods were 80 C. in each case. The test specimens were used in the dry state if not otherwise specified; for this purpose, they were stored at room temperature for at least 48 h after the injection molding in a dry environment, i.e. over silica gel.

(34) In the case of plates (2 mm60 mm60 mm) for determining the optical properties, the surfaces of the cavity of the injection mold were given a mirror finish so that the molded bodies (plates) had a high gloss surface having an arithmetical mean roughness Ra of 0.01 to 0.08 m and/or a surface roughness Rz of 0.05 to 1.0 m, in accordance with DIN EN ISO 4287.

3.4 Results

(35) 3.4.1 Single-Layer Molded Bodies

(36) The following Table 2 relates to examples and comparison examples in accordance with the invention.

(37) TABLE-US-00004 TABLE 2 Examples and comparison examples. Unit B1 B2 B3 VB1 VB2 VB3 Components Polyamide 1 Wt % 24 80 (Component (A1)) Polyamide 2 Wt % 64 61 19.06 (Component (A1)) Proportion of (A1) in Wt % 80 80 30 25 100 (A) Polyamide 3 Wt % 16 15.25 56 57.19 80 (Component (A2)) Proportion of (A2) in Wt % 20 20 70 75 100 (A) 1 0.003 0.003 0.296 0.003 2 0.008 0.008 0.008 0.008 2/1 2.67 2.67 0.027 2.67 PA 6/12 Wt % 3.75 3.75 Glass fiber Wt % 20 20 20 20 20 20 Properties Tg of Mixture A C. 141 133 146 132 Haze of Mixture A % 0.5 0.6 0.8 0.7 Transparency of % 93 93 92 92 Mixture A Tg of the molding C. 140 134 145 131 143 147 compound Haze of the molding % 17 13 15 47 52 95 compound Transparency of the % 89 90 90 82 88 84 molding compound Ra m 0.059 0.052 0.056 0.060 0.059 0.062 Plate 60 60 2 mm Rz m 0.792 0.741 0.785 0.791 0.788 0.801 Plate 60 60 2 mm Modulus of elasticity MPa 6600 6500 6700 6400 6200 6750 Failure stress MPa 153 155 152 145 143 135 Elongation at break % 4.1 4.1 3.5 3.4 4.0 2.1 Impact resistance kJ/mm.sup.2 63 58 46 20 52 52 Notch impact kJ/mm.sup.2 11 10 10 11 11 10 resistance HDT A C. 134 132 133 131 131 135 HDT B C. 138 137 138 136 137 140

(38) 3.4.2 3-Layer Molded Bodies of the Dimension 60602 mm

(39) Manufacture of the Multilayer Molded Bodies

(40) The following multilayer molded bodies of the dimension 60602 mm were manufactured by back injection molding of films of non-reinforced, transparent polyamide using the polyamide molding compound in accordance with the invention. The manufacture took place on an injection molding machine of Arburg 420C 1000-250 using the conditions described above for the 60602 mm plates. Two extruded films composed of the polyamide 3 (PA 6I/6T/612/MACMI/MACMT/MACM12; component (A2)) each having a thickness of 100 m were cut to the size 60600.1 mm, were placed into the injection molding tool, and the remaining cavity between the two films after the closing of the tool was filled by injecting the polyamide molding compound in accordance with the invention from example B1 or B3. After cooling, the multilayer molded body was demolded and the transparency and haze were determined in accordance with ASTM D1003. The insertion films of polyamide 3 can no longer be removed from the multilayer molded body after the injection molding process, but were rather connected with material continuity to the molding compound from the examples B1 and B3.

(41) TABLE-US-00005 Multilayer molded body 1 Film of polyamide 3 (t) Design of the multilayer molded External Molding compound of body of the dimension Central example B1 60 60 2 mm Internal Film of polyamide 3 (b) Transparency % 90 Haze % 11 Ra (t/b) (plate 60 60 2 mm) m 0.023/0.025 Rz (t/b) (plate 60 60 2 mm) m 0.241/0.276

(42) TABLE-US-00006 Multilayer molded body 2 Film of polyamide 3 Design of the multilayer molded External Molding compound of body of the dimension Central example B3 60 60 2 mm Internal Film of polyamide 3 Transparency % 91 Haze % 9.5 Ra (t/b) (plate 60 60 2 mm) m 0.024/0.026 Rz (t/b) (plate 60 60 2 mm) m 0.268/0.301

4. DISCUSSION OF THE RESULTS

(43) It can be seen from Table 2 that the polyamide molding compounds in accordance with the invention in accordance with examples B1 to B3 have a very low haze of 13 to 17% and a high transparency of 80 to 90%. The polyamide molding compounds in accordance with the comparison examples VB1 to VB4 in contrast demonstrate a much higher haze in the range from 52 to 95%.

(44) The polyamide molding compounds in accordance with B1 and B2 have a proportion of polyamide (A1) in the polyamide mixture (A) of 80 wt % and the ratio 2/1 is 2.67. The polyamide molding compound likewise in accordance with the invention in accordance with B3 in contrast has an excess of polyamide (A2) in the polyamide mixture (A). The proportion of polyamide (A2) in the polyamide mixture (A) amounts to 61.2 wt %, with the ratio 2/1 being 0.027.

(45) The comparison of the examples B1 to B3 in accordance with the invention with the comparison examples VB2 to VB3, that each only comprise one polyamide (A1) or (A2), illustrates that a mixture of the polyamides (A1) and (A2) is absolutely necessary to achieve good haze values. Since the surface roughness in all examples was able to be kept at the same high level, the differences in transparency and in haze clearly originate from the selected composition of the molding compound.

(46) The comparison example VB1 relates to a polyamide molding compound that comprises a mixture of the polyamides (A1) and (A2). The component (A2) is present in excess in the mixture (A) here and its proportion amounts to 75 wt %, with the ratio 2/1 here amounting to 2.67 and thus the condition proportion of component (A1)50 wt % in the mixture (A) when 2/1>1 not being satisfied. The haze of the polyamide molding compound in accordance with VB1 is at 47% and is thus considerably above that of the polyamide molding compounds in accordance with the invention in accordance with the examples B1 to B3 that satisfy one of the conditions proportion of the component (A1)50 wt % in the mixture (A) when 2/1>1 or proportion of the component (A2)50 wt % in the mixture (A) when 2/1<1.

(47) The multilayer molded bodies 1 and 2 are characterized by good transparency and low haze. Molded bodies having a high surface quality, in particular a low mean roughness Ra and a low surface roughness surface R.sub.z, result despite the high viscosity starting substances (polyamides A1 and A2). Due to the high viscosity of the starting substances, on the other hand, the high strength and toughness of the molded bodies is ensured; the impact resistance and the elongation at break are in particular improved in comparison with low viscosity matrices.

(48) Providing polyamide molding compounds reinforced with a glass filler that also have very good optical properties, in particular low haze, in addition to good mechanical properties is therefore surprisingly only successful by the specific feature combination in accordance with the invention described herein.