Filler materials having surface coating made from water soluble polyamides

Abstract

Fillers are proposed, with the exception of layered silicates, which have a surface coating, which comprises a water-soluble polyamide or multiple water-soluble polyamides, wherein at least one of these water-soluble polyamides is produced by polycondensation from monomer components, which comprise at least one dicarboxylic acid and at least one selected ether diamine, preferably having linear oxypropyl amino end groups. Fillers coated in this manner are suitable for use in the production of filled and/or reinforced thermoplastic plastics molding materials. Thermoplastic plastics molding materials which contain fillers having such a surface coating have good mechanical properties and few emissions (low outgassing).

Claims

1. A filler, with the exception of layered silicates, which has a surface coating, wherein this surface coating comprises a water-soluble polyamide or multiple water-soluble polyamides, wherein at least one of these water-soluble polyamides is produced by polycondensation from the following monomer components: (a) at least one linear-aliphatic, branched-aliphatic, cycloaliphatic, and/or aromatic dicarboxylic acid having 6 to 36 C atoms; and (b1) 25-100 mol-% in relation to the total of the molar quantities of the monomer components (b1)+(b2)+(b3) of at least one diamine selected from the group consisting of 4-oxaheptane-1,7-diamine, 4,7-dioxadecane-1,10-diamine, 4,7-dioxa-5- methyl-decane- 1,10-diamine, 6-oxa-undecane-1,11-diamine, 4,8-dioxa-undecane-1,11-diamine, 4,8-dioxa-5-methyl-undecane-1,11-diamine, 4,8-dioxa-5,6-dimethyl-undecane-1,11-diamine, 4,9-dioxa-dodecane-1,12-diamine, 4,7,10-trioxa-tridecane-13-diamine, 4,7,10-trioxa-5,8-dimethyl-tridecane-1,13-diamine, 4,11-dioxa-tetradecane-1,14-diamine, 4,7,11-trioxa-tetradecane-1,14-diamine, 4,7,10,13-tetraoxa-hexadecane-1,16-diamine 4,7,10,13,16-pentaoxa-nonadecane-1,19-diamine, and 4,17-dioxa-eicosane-1,20-diamine; and (b2) 0-50 mol-% in relation to the total of the molar quantities of the monomer components (b1)+(b2)+(b3) of at least one linear-aliphatic, branched-aliphatic, cycloaliphatic, and/or aromatic diamine having 2 to 36 C atoms; and (b3) 0-50 mol-% in relation to the total of the molar quantities of the monomer components (b1)+(b2)+(b3) of at least one compound from the group consisting of oligooxyethylene diamines, polyoxyalkylene diamines, and polyalkylene glycols; and (c) 0-45 mol-% of at least one lactam and/or at least one amino carboxylic acid; wherein the molar quantity of the monomer component (a) in relation to the total of the molar quantities of the monomer components (b1)+(b2)+(b3) has a molar ratio in the range of 0.8 to 1.2, and wherein the fraction of the monomer component (c) relates to the molar total of all monomer components (a)+(b1)+(b2)+(b3)+(c) forming the at least one water-soluble polyamide.

2. The filler according to claim 1, wherein for at least one of the water-soluble polyamides of the surface coating, adipic acid and/or sebacic acid are selected as monomer component (a), 4,7,10-trioxa-tridecane-1,13-diamine and/or 4,7,10,13-tetraoxa-hexadecane-1,16-diamine are selected as monomer component (b1), and optionally hexane diamine is selected as monomer component (b2).

3. The filler according to claim 1, wherein the surface coating consists at least 50 wt.-% of the water-soluble polyamide or multiple water-soluble polyamides.

4. The filler according to claim 1, wherein the surface coating comprises, in addition to the at least one water-soluble polyamide, at least one adhesion promoter.

5. The fillers according to claim 4, wherein the at least one adhesion promoter makes up 10 to 50 wt.-% of the surface coating, in relation to the total mass of the surface coating calculated as the dry mass.

6. The filler according to claim 1, wherein the surface coating does not contain a surfactant and does not contain an adhesion promoter.

7. The filler according to claim 1, wherein the fillers are selected from inorganic and/or organic materials.

8. The filler according to claim 1, wherein the fillers are selected from fibrous and/or particulate materials.

9. The filler according to claim 1, wherein the fillers are selected from the group consisting of glass fibers, carbon fibers, metal fibers, boron fibers, aramid fibers, organic flame retardants, inorganic flame retardants, and/or synergists, thermally and/or electrically conductive additives, and mineral fillers, wherein layered silicates are excluded.

10. A method for producing filled and/or reinforced thermoplastic plastics molding materials, comprising incorporating a filler into at least one polymer, wherein the filler differs from layered silicates and has a surface coating, and wherein this surface coating comprises a water-soluble polyamide or multiple water-soluble polyamides, wherein at least one of these water-soluble polyamides is produced by polycondensation from the following monomer components: (a) at least one linear-aliphatic, branched-aliphatic, cycloaliphatic, and/or aromatic dicarboxylic acid having 6 to 36 C atoms; and (b1) 25-100 mol-% in relation to the total of the molar quantities of the monomer components (b1)+(b2)+(b3) of at least one diamine selected from the group consisting of 4-oxaheptane-1,7-diamine, 4,7-dioxadecane-1,10-diamine, 4,7-dioxa-5-methyl-decane-1,10-diamine, 6-oxa-undecane-1,11-diamine, 4,8-dioxa-undecane-1,11-diamine, 4,8-dioxa-5-methyl-undecane-1,11-diamine, 4,8-dioxa-5,6-dimethyl-undecane-1,11-diamine, 4,9-dioxa-dodecane-1,12-diamine, 4,7,10-trioxa-tridecane-1,13-diamine, 4,7,10-trioxa-5,8-dimethyl-tridecane-1,13-diamine, 4,11-dioxa-tetradecane-1,14-diamine, 4,7,11- trioxa-tetradecane-1,14-diamine, 4,7,10,13-tetraoxa-hexadecane-1,16-diamine, 4,7,10,13,16-pentaoxa-nonadecane-1,19-diamine, and 4,17-dioxa-eicosane-1,20-diamine; and (b2) 0-50 mol-% in relation to the total of the molar quantities of the monomer components (b1)+(b2)+(b3) of at least one linear-aliphatic, branched-aliphatic, cycloaliphatic, and/or aromatic diamine having 2 to 36 C atoms; and (b3) 0-50 mol-% in relation to the total of the molar quantities of the monomer components (b1)+(b2)+(b3) of at least one compound from the group consisting of oligooxyethylene diamines, polyoxyalkylene diamines, and polyalkylene glycoles; and (c) 0-45 mol-% of at least one lactam and/or at least one amino carboxylic acid; wherein the molar quantity of the monomer component (a) in relation to the total of the molar quantities of the monomer components (b1)+(b2)+(b3) has a molar ratio in the range of 0.8 to 1.2, and wherein the fraction of the monomer component (c) relates to the molar total of all monomer components (a)+(b1)+(b2)+(b3)+(c) forming the at least one water-soluble polyamide.

11. The method of claim 10, wherein the surface coating is applied to the filler from an aqueous solution, which comprises the water-soluble polyamide or multiple water-soluble polyamides.

12. The method of claim 10, wherein the at least one polymer is selected from the group consisting of polyamides, polycarbonates, polystyrene, polyacrylates, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-styrene copolymer, functionalized polyolefms, polyoxymethylene, polyesters, polysulfones, polyphenylene ether, polyphenylene sulfide, polyphenylene oxide, liquid crystal polymers, polyether ketone, polyether ether ketone, polyimide, polyamide imide, polyester imide, polyester amide, polyurethanes, polysiloxane, and mixtures and copolymers based on these polymers.

13. The method of claim 12, wherein the at least one polymer comprises a polyamide.

14. A thermoplastic plastics molding material, which contains at least one filler different from layered silicates, which has a surface coating which comprises a water-soluble polyamide or multiple water-soluble polyamides, wherein at least one of these water-soluble polyamides is produced by polycondensation from the following monomer components: (a) at least one linear-aliphatic, branched-aliphatic, cycloaliphatic, and/or aromatic dicarboxylic acid having 6 to 36 C atoms; and (b1) 25-100 mol-% in relation to the total of the molar quantities of the monomer components (b1)+(b2)+(b3) of at least one diamine selected from the group consisting of 4-oxaheptane-1,7-diamine, 4,7-dioxadecane-1,10-diamine, 4,7-dioxa-5-methyl-decane-1,10-diamine, 6-oxa-undecane-1,11-diamine, 4,8-dioxa-undecane-1,11-diamine, 4,8-dioxa-5-methyl-undecane-1,11-diamine, 4,8-dioxa-5,6-dimethyl-undecane-1,11-diamine, 4,9-dioxa-dodecane-1,12-diamine, 4,7,10-trioxa-tridecane-1,13-diamine, 4,7,10-trioxa-5,8-dimethyl-tridecane-1,13-diamine, 4,11-dioxa-tetradecane-1,14-diamine, 4,7,11-trioxa-tetradecane-1,14-diamine, 4,7,10,13-tetraoxa-hexadecane-1,16-diamine, 4,7,10,13,16-pentaoxa-nonadecane-1,19-diamine, and 4,17-dioxa-eicosane-1,20-diamine; and (b2) 0-50 mol-% in relation to the total of the molar quantities of the monomer components (b1)+(b2)+(b3) of at least one linear-aliphatic, branched-aliphatic, cycloaliphatic, and/or aromatic diamine having 2 to 36 C atoms; and (b3) 0-50 mol-% in relation to the total of the molar quantities of the monomer components (b1)+(b2)+(b3) of at least one compound from the group consisting of oligooxyethylene diamines, polyoxyalkylene diamines, and polyalkylene glycoles; and (c) 0-45 mol-% of at least one lactam and/or at least one amino carboxylic acid; wherein the molar quantity of the monomer component (a) in relation to the total of the molar quantities of the monomer components (b1)+(b2)+(b3) has a molar ratio in the range of 0.8 to 1.2, and wherein the fraction of the monomer component (c) relates to the molar total of all monomer components (a)+(b1)+(b2)+(b3)+(c) forming the at least one water-soluble polyamide.

15. The thermoplastic plastics molding material according to claim 14, wherein the plastics molding material contains at least one polymer, which is selected from the group consisting of polyamides, polycarbonates, polystyrene, polyacrylates acrylonitrile-butadiene-styrene copolymer, acrylonitrile-styrene copolymer, functionalized polyolefms, polyoxymethylene, polyesters, polysulfones, polyphenylene ether, polyphenylene sulfide, polyphenylene oxide, liquid crystal polymers, polyether ketone, polyether ether ketone, polyimide, polyamide imide, polyester imide, polyester amide, polyurethanes, polysiloxane, and mixtures and copolymers based on these polymers.

16. The thermoplastic plastics molding material according to claim 15, wherein the at least one polymer of the plastics molding material comprises a polyamide, so that it is a polyamide molding material.

17. The polyamide molding material according to claim 16, wherein the polyamide molding material contains at least one of the fibrous filler having a surface coating and the particulate filler having a surface coating.

Description

EXAMPLES B7 TO B9 AND COMPARATIVE EXAMPLES VB7 TO VB9

(1) The production of compounds from the glass fiber rovings coated with PA1, PU1, or PU2 (see Table 1) and the polyamide granulates listed in Table 3 and also additives was performed on a 36D long double-screw extruder ZSE 27 MAXX (Leistritz, Nuremberg) having a screw diameter of 27 mm. In each case 15 coils of the sized (coated) rovings with titer of 40 tex were assembled by doubling folding to form 600 tex roving strands and wound onto 30 cm long paperboard sleeves with three-inch internal diameter. Each 4 such assembled roving strands with 600 tex each were supplied at 18D (i.e., half screw length) through a side feeder to the extruder. By way of a preceding calibration using 2400 tex standard glass fiber rovings, the extruder screw speed correct for a glass fiber content of 40 wt.-% was ascertained (cf. compounding parameters in Table 2).

(2) The polyamide granulates indicated in Table 3 and the additives were all metered together into the intake zone of the double screw extruder. The most important process parameters are summarized in Table 2.

(3) The extruded strand was cooled in the water bath and continuously granulated. The granulate was dried for 24 hours at 110 C. in vacuum of 30 mbar.

(4) Processing:

(5) The molding materials (granulates) produced by compounding of all examples and comparative examples were injection molded using an injection molding machine Arburg Allrounder 320-210-750 into sample specimens at defined cylinder temperatures of zones 1 to 4 and a defined mold temperature (see Table 2).

(6) TABLE-US-00002 TABLE 2 compounding and injection molding conditions for the examples and comparative examples Conditions for examples and comparative examples Compounding and processing parameters 1 2, 6 3, 4 5 7 8 9 Compounding Cylinder temperatures 250 280 330 330 280 330 330 [ C.] Screw speed [RPM] 200 200 150 150 300 300 300 Throughput [kg/h] 15 15 8 8 7.5 7.5 7.5 Injection molding Cylinder temperatures 240 280 330 330 280 330 330 [ C.] Mold temperature 80 80 140 140 100 140 140 [ C.] Screw circumferential 15 15 15 15 15 15 15 velocity [m/s]
Explanation of Table 2:

(7) The mentioned double screw extruder ZSE 27 MAXX (Leistritz, Nuremberg) was used during the compounding of the examples (and comparative examples) 7, 8, and 9. In the examples (and comparative examples) 1 to 6 described subsequently, in contrast, a dual-shaft extruder from Werner and Pfleiderer having screw diameter of 25 mm as mentioned there was used. The throughput was determined in doing so by the feed metering in the intake zone of the respective extruder. The injection molding to form the sample specimens and test specimens was performed as mentioned foregoing, however, in all examples (and comparative examples) on the same injection molding machine.

(8) TABLE-US-00003 TABLE 3 Composition and properties of examples B7 to B9 and comparative examples VB7 to VB9 Composition Unit B7 VB7-1 VB7-2 B8 VB8-1 VB8-2 B9 VB9-1 VB9-2 PA 66 wt.-% 44.68 44.68 44.68 PA 6T/6I wt.-% 59.58 59.58 59.58 53.58 53.58 53.58 PA 6I/6T wt.-% 14.9 14.9 14.9 SZM wt.-% 6 6 6 Additive 1 wt.-% 0.12 0.12 0.12 0.15 0.15 0.15 0.15 0.15 0.15 Additive 2 wt.-% 0.30 0.30 0.30 0.15 0.15 0.15 0.15 0.15 0.15 Additive 3 wt.-% 0.12 0.12 0.12 0.12 0.12 0.12 Glass fiber + 0.6% PA1 wt.-% 40 40 40 Glass fiber + 0.6% PU1 wt.-% 40 40 40 Glass fiber + 0.6% PU2 wt.-% 40 40 40 Properties of granulate Glass fiber length m 308 308 269 289 298 296 281 276 268 Glass fiber length D10 m 88 81 83 76 105 86 77 86 70 Glass fiber length D50 m 264 268 241 233 269 262 253 245 236 Glass fiber length D90 m 576 581 489 605 524 541 519 500 519 Mechanical material properties dry Tensile modulus of MPa 11400 11600 11800 12500 12900 12800 11600 11200 11500 elasticity Maximum tensile strength MPa 205 205 205 235 240 235 225 220 220 Elongation at break % 4.1 3.7 4.0 2.3 2.3 2.2 3.1 2.8 2.8 Impact strength kJ/m.sup.2 96 89 97 63 66 64 92 90 89 Notched impact strength kJ/m.sup.2 94 96 94 5.1 6.1 6.2 Mechanical material properties conditioned Tensile modulus of MPa 10.4 11.1 10.9 elasticity Tensile strength MPa 165 160 165 Elongation at yield % 3.9 3.6 3.8 Impact strength kJ/m.sup.2 94 96 94 Notched impact strength kJ/m.sup.2 11.0 10.9 12.1 Emission Emission 120 C. g/g 1.2 4.2 2.3 Emission 200 C. g/g 7.2 65.0 12.9 Captions for Table 3 PA 66 Partially crystalline, aliphatic polyamide made of 1,6-hexane diamine and adipic acid, having a melting point of 260 C. and a relative solution viscosity of 1.85. PA 6T/6I XE 3733 NK natur: partially crystalline, partially aromatic polyamide made of 1,6-hexane diamine, terephthalic acid, and isophthalic acid, having a melting point of 335 C.; from EMS-Chemie AG, Switzerland. PA 6I/6T Grivory G21 natur: amorphous, partially aromatic polyamide made of 1,6-hexane diamine, isophthalic acid, and terephthalic acid; from EMS-Chemie AG, Switzerland. SZM Impact toughness modifier Lotader AX8840: random copolymer made of ethylene and glycidyl methacrylate; from Arkema, France. Additive 1: Hostanox PAR 24, tris(2,4-di-tert-butylphenyl)phosphite; commercial product of Clariant, Switzerland. Additive 2: Irganox 1098, N,N-hexamethylene-bis-3,5-di-tert.-butyl-4-hydroxyhydrocinnamide; commercial product of BASF SE, Germany. Additive 3: Brggolen P22, nucleating agent for polyamides based on condensation products of oxalic acid with ethylene diamine; from Brggemann Chemical, Heilbronn, Germany.

EXAMPLES B1 TO B6 AND COMPARATIVE EXAMPLES VB1 TO VB6

(9) The components specified in Tables 4 and 5 were compounded in a dual-shaft extruder from Werner and Pfleiderer having a screw diameter of 25 mm with predefined process parameters (see Table 2), wherein the polyamide granulates and the additives were metered in the intake zone, while the glass fibers were metered via a side feeder 3 housing units before the die into the polymer melt. The molding materials according to Table 4 were drawn off as a strand from a die having 3 mm diameter and granulated after water cooling. The granulate was dried for 24 hours at 110 C. in vacuum of 30 mbar. For the molding materials from Table 5, the granulation was performed by means of underwater granulation or hot die-face cutting underwater, in which the polymer melt was pressed through a perforated die and granulated in a water stream by a rotating cutter directly after exiting from the die.

(10) After granulation and drying at 120 C. for 24 hours, the granulate properties were measured and the test specimens were produced for the measurements of the further properties listed in Tables 4 and 5.

(11) TABLE-US-00004 TABLE 4 Composition and properties of examples B1 and B2 and comparative examples VB1 and VB2 Composition Unit VB1 B1-1 B1-2 VB2 B2-1 B2-2 PA 12 wt.-% 50 50 50 PA 66 wt.-% 50 50 50 Glass fiber A1 wt.-% 50 50 Glass fiber A2 wt.-% 50 50 Glass fiber B wt.-% 50 50 Properties Tensile modulus of MPa 11900 11600 11800 16000 15500 15600 elasticity Breaking strength MPa 144 160 162 220 230 230 Elongation at break % 3.3 4.0 3.9 3.5 4.0 4.2 Impact strength kJ/m.sup.2 62 70 75 84 90 92 Notched impact strength kJ/m.sup.2 16 18 20 12 14 15 HDT A C. 169 170 170 250 250 255 HDT C C. 133 135 134 220 222 224

(12) TABLE-US-00005 TABLE 5 Composition and properties of examples B3 to B6 and comparative examples VB3 to VB6 Composition Unit VB3 B3 VB4 B4 VB5 B5 VB6 B6 PA 10T/6T wt.-% 35 35 44 44 57 57 PA 12 wt.-% 39.4 39.4 SZM wt.-% 4 4 5 5 S/V packet wt.-% 1 1 1 1 1 1 0.6 0.6 Glass fiber A3 wt.-% 10 30 Glass fiber B wt.-% 10 30 Exolit OP 1230 wt.-% 12 Aluminum diethyl phosphinate wt.-% 12 coated with water-soluble polyamide A1 (2.5 wt.-% with respect to this filler) Boron nitride B wt.-% 50 50 60 Boron nitride A3 wt.-% 50 50 60 Properties Tensile modulus of MPa 13800 13700 8600 8500 10900 10800 7900 7800 elasticity Breaking strength MPa 56 65 51 55 154 175 42 51 Elongation at break % 0.5 0.8 1.3 1.8 2.9 3.5 1.4 2.1 Impact strength kJ/m.sup.2 8.6 12 6.0 9.2 14 21 Notched impact strength kJ/m.sup.2 4.7 6.3 3.2 4.5 3.2 4.3 HDT A C. 243 245 172 175 >280 >280 132 130 HDT C C. 134 138 112 111 190 198 86 90 Thermal conductivity Through W/mK 1.7/ 2.0/ 1.3/ 1.8/ 1.7/ 1.6/ Plane/In plane (UL 3.2 mm) 7.3 7.7 5.0 7.0 8.9 8.7 Fire classification UL94 (0.8 mm) V0 V0 Captions for Tables 4 and 5 PA 10T/6T Partially aromatic polyamide made of terephthalic acid, 1,10-decane diamine (85 mol-%), and 1,6-hexane diamine (15 mol-%), having a melting point of 307 C. and a relative solution viscosity of 1.64. PA 66 Partially crystalline, aliphatic polyamide made of 1,6-hexane diamine and adipic acid, having a melting point of 260 C. and a relative solution viscosity of 1.85. PA 12 Partially crystalline, aliphatic polyamide made of laurin lactam, having a melting point of 178 C. and a relative solution viscosity of 1.90. Glass fiber B Cut glass fibers Vetrotex 995 made of E glass, having a length of 4.5 mm and a diameter of 10 m (circular cross section) from Owens Corning Fiberglas, coated using polyurethane resin (prior art). Glass fiber A1 Cut glass fibers made of E glass, having a length of 4.5 mm and a diameter of 10 m (circular cross section), coated using water-soluble polyamide A1 using the coating solution PA1 (Table 1). The dry weight of the coating is 1.1 wt.-% in relation to the coated glass fibers. Glass fiber A2 Cut glass fibers made of E glass, having a length of 4.5 mm and a diameter of 10 m (circular cross section), coated using a water-soluble polyamide A2 with use of a coating solution similar to PA1, in which the water-soluble polyamide A1 was replaced by the water-soluble polyamide A2. The dry weight of the coating is 1.2 wt.-% in relation to the coated glass fibers. Glass fiber A3 Cut glass fibers made of E glass, having a length of 4.5 mm and a diameter of 10 m (circular cross section), coated using a water-soluble polyamide A3 with use of a coating solution similar to PA1, in which the water-soluble polyamide A1 was replaced by the water-soluble polyamide A3. The dry weight of the coating is 0.8 wt.-% in relation to the coated glass fibers. Boron nitride B Carbotherm PTCP 30 from St. Gobain Ceramics. Boron nitride A3 Hexagonal boron nitride having a mean particle size of 30 m (D50), coated using pure water-soluble polyamide A3. The fraction of polyamide A3 in relation to the coated boron nitride is 2.4 wt.-%. Exolit OP 1230 Flame retardant from Clariant, having main component aluminum diethyl phosphinate. SZM Lotader AX8840 (impact toughness modifier). S/V packet Mixture of a standard heat stabilizer for polyamides and processing aids, for example, lubricants.

(13) The measurements of the properties were carried out according to the following standards and on the following test specimens:

(14) Tensile Modulus of Elasticity:

(15) ISO 527 using a traction speed of 1 mm/min ISO tension rod, standard: ISO/CD 3167, type A1, 17020/104 mm, temperature 23 C.
Breaking Strength, Elongation at Break: ISO 527 using a traction speed of 5 mm/min ISO tension rod, standard: ISO/CD 3167, type A1, 17020/104 mm, temperature 23 C.
Impact Strength, Notched Impact Strength According to Charpy: ISO 179 ISO testing rod, standard: ISO/CD 3167, type B1, 80104 mm at temperature 23 C.
Melting Point (Tm), Melting Enthalpy (Hm), and Glass Transition Temperature (Tg): ISO standard 11357-11-2 granulate Differential scanning calorimetry (DSC) was carried out at a heating rate of 20 C./min. For the glass transition temperature (Tg), the temperature is specified for the middle stage or the inflection point.
Relative Viscosity (=Relative Solution Viscosity): DIN EN ISO 307 granulate 0.5 g polyamide dissolved in 100 ml m-Kresol, measurement at temperature 20 C. calculation of the relative viscosity (RV) according to RV=t/t.sub.0 based on section 11 of the standard.
HDT A (1.8 MPa) and HDT C (8 MPa): The determination of HDT A (1.8 MPa) and HDT C (8 MPa) were performed according to ISO 75 on an ISO impact rod having the dimensions 80104 mm.
Thermal Conductivity: According to DIN EN 821 on so-called V0 rods 125133.2 mm using LFA 447 Nanoflash from Netzsch-Geratebau, Selb, Germany
Vertical Fire Test: UL-94 Underwriters Laboratories testing rod 125130.8 mm
Glass Fiber Length: Ascertained weight-averaged fiber length according to ISO/DIS 22314 on each of at least 7000 glass fibers using the FASEP report system from High Precision Dipl.-Ing. (TH) Norbert Hohn, Darmstadt, Germany. Glass fiber length D10, D50, D90: fiber length at which 10, 50, 90 wt.-% of the fibers are shorter than the specified value.
Emission (Outgassing): 100 mg granulate was initially heated in a test tube for 60 minutes at 120 C. (FOG conditions according to VDA278) and subsequently heated at 200 C. for 45 minutes and the released compounds were quantitatively analyzed by means of GC (FID). For the analysis, all peaks present in the chromatogram were integrated and calculated as the toluene equivalent in g/g.

(16) The experimental results of Tables 3, 4, and 5 show the general suitability of water-soluble polyamides for the coating of fillers in polyamide molding materials. Breaking strength, impact strength, and notched impact strength, as well as the emission of the polyamide molding materials according to the invention having surface-coated fillers according to the invention are equivalent or improved in relation to the prior art. The thermal stability of the film former was also able to be improved. The thermal stability of the water-soluble polyamide was 55-60 above that of the known polyurethane film formers. This improvement is particularly impressive in consideration of the fact that in U.S. Pat. No. 5,804,313, which was mentioned at the outset, the use of a conventional water-soluble polyamide in the glass fiber sizes in comparison to glass fibers having a polyurethane size was accompanied by worsening of the mechanical properties of the polyamide molding materials reinforced thereby. In the present examples of the invention, however, significantly better properties were achieved using water-soluble polyamides according to the claims, and also in comparison to glass fibers (glass fiber B) having polyurethane coating, i.e., with identical comparison basis. This surprising effect was not to be predicted by a person skilled in the art. The present invention therefore provides a valuable contribution to the improvement of the quality of filled and/or reinforced thermoplastic plastics molding materials, in particular corresponding polyamide molding materials.