Microspheres

Abstract

The present invention relates to microspheres and to the use thereof, preferably as laser-absorbing additive, and to a process for the production thereof.

Claims

1. A microsphere comprising core/shell particles dispersed in a polyolefin carrier matrix, wherein said core of the core/shell particles comprises, an absorber which is a mixture consisting of Bi.sub.2O.sub.3 and TiO.sub.2 (Bi.sub.2O.sub.3/TiO.sub.2), a film former which comprises PPO/PS or PBT, and said shell of the core/shell particles comprises at least one compatibilizer that is a grafted polyolefin, ethylene-GMA or styrene-ethylene-butylene-styrene (SEBS), wherein the D.sub.50 value for TiO.sub.2 is in the range of 0.02-5 m and wherein said microsphere comprises 25-70% by weight of the Bi.sub.2O.sub.3/TiO.sub.2, 8-25% by weight of the PPO/PS or PBT, 0.5-7.5% by weight of grafted polyolefin, ethylene-GMA or SEBS compatibilizer, 20-50% by weight of the polyolefin carrier matrix, and may also comprise 0-5% by weight of additives, based on the microsphere, where the % by weight add up to 100%.

2. The microsphere according to claim 1, wherein the Bi.sub.2O.sub.3/TiO.sub.2 weight ratio is 99:1 to 1:99 parts.

3. The microsphere according to claim 1, wherein the non olefinic polymer PPO/PS or PBT is also a color former.

4. The microsphere according to claim 3, wherein the color former is PPO/PS.

5. The microsphere according to claim 1, wherein the grafted polyolefin compatibilizer is a grafted polyethylene or grafted polypropylene.

6. The microsphere according to claim 1, wherein the grafted polyolefin compatibilizer is a polyethylene grafted to maleic anhydride or a polypropylene grafted to maleic anhydride.

7. The microsphere according to claim 1, wherein the compatibilizer is styrene-ethylene/butylene-styrene (SEBS).

8. The microsphere according to claim 1, wherein the polyolefin carrier matrix is a linear low-density polyethylene (LLDPE), very low-density polyethylene (VLDPE), low-density polyethylene (LDPE) or a metallocene-polyethylene (m-PE).

9. The microsphere according to claim 1, wherein the additives are selected from the group of a glass fiber, a carbon fiber, a nanofiller, a pigment, a dye, a colorant, a filler, a processing assistant, a stabilizer an antioxidant, plasticiser, an impact modifier, a flame retardant, a mould-release agent or foam former.

10. The microsphere according to claim 1, wherein said microsphere has an average particle size of 0.5-3.0 microns.

11. The microsphere according to claim 1, wherein said microsphere consists of 25-70% by weight of Bi.sub.2O.sub.3/TiO.sub.2 (=core) 8-25% by weight of PPO/PS or PBT (=core film former) 0.5-7.5% by weight of grafted polyolefin (=shell compatibilizer) 20-50% by weight of polyolefin carrier (=matrix) 0-5% by weight of additives based on the microsphere, where the % by weight add up to 100%.

12. The microsphere according to claim 1, wherein said microsphere consists of 25-70% by weight of Bi.sub.2O.sub.3/TiO.sub.2 (=core) 8-25% by weight of PPO/PS or PBT (=core film former) 0.5-7.5% by weight of SEBS(=shell compatibilizer) 20-50% by weight of polyolefin carrier (=matrix) 0-5% by weight of additives based on the microsphere, where the % by weight add up to 100%.

13. The microsphere according to claim 1, wherein said microsphere consists of 25-70% by weight of Bi.sub.2O.sub.3/TiO.sub.2 (=core) 8-25% by weight of PPO/PS or PBT (=core film former) 0.5-7.5% by weight of ethylene-GMA (=shell compatibilizer) 20-50% by weight of polyolefin carrier (=matrix) 0-5% by weight of additives based on the microsphere, where the % by weight add up to 100%.

14. A process for the production of the microsphere according to claim 1 wherein said microsphere is formed by reactive extrusion.

15. A method for preparing a laser marking or laser welding composition which comprises adding the microsphere according to claim 1 into a laser marking or laser welding composition.

16. A laser-markable and laser-weldable composition, comprising a matrix polymer and at least one microsphere according to claim 1.

17. The laser-markable and laser-weldable composition according to claim 16, wherein the composition comprises 0.1-1.0% by weight of said at least one microsphere.

18. The laser-markable and laser-weldable composition according to claim 16, wherein the matrix polymer is polyethylene (PE), polypropylene (PP), polyamide (PA), polyester, polyether, polyphenylene ether, polyacrylate, polyurethane (PU), polyoxymethylene (POM), polymethacrylate, polymethyl methacrylate (PMMA), polyvinyl acetate (PVAC), polystyrene (PS), acrylonitrile-butadiene-styrene (ABS), acrylonitrile-styrene-acrylate (ASA), ABS graft polymer, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polycarbonate (PC), polyether sulfones, polyether ketone, thermoplastic polyurethane (TPU), thermoplastic elastomers (TPE), epoxy resin (EP), silicone resin (SI), unsaturated polyester resin (UP), phenol-formaldehyde resin (PF), urea-formaldehyde resin (UF), melamine resin (MF), ultrahigh-molecular-weight polyethylene (UHMWPE), styrene plastics, styrene-acrylonitrile (SAN), thermoplastic vulcanisates, thermoplastic elastomers, silicone rubbers or copolymers thereof and/or mixtures thereof.

19. A process for the preparation of the laser-markable and laser-weldable composition according to claim 16, wherein the matrix polymer is mixed with the microspheres and optionally further additives, and finally the resulting mixture is shaped by exposure to heat.

20. The microsphere according to claim 1, wherein the D.sub.50 value for the TiO.sub.2 is 0.05-2.5 m.

21. The microsphere according to claim 1, wherein the D.sub.50 value for the TiO.sub.2 is 0.1-1 m.

Description

(1) The following examples are intended to explain the invention, but not to restrict it. The percentages relate to the weight, unless indicated otherwise.

EXAMPLES

(2) Process for the preparation of a laser marking absorber concentrate (LMAC, Table 1) and the comparative compounding concentrate (CCC, Table 1.1)

(3) using

(4) as the first polymer (core polymer):

(5) P1.0 polybutylene terephthalate 1060 (DSM) P1.1 Noryl 6850H-100 (mixture of PPO/PS 50/50, Sabic) P1.2 polybutylene terephthalate Crastin 6130 NC010 (Dupont) as the second polymer (shell: compatibiliser): P2.0 Fusabond 525N polyethylene (Dupont), grafted to 0.9% by weight of MA P2.1 Kraton 1650G (Dupont) P2.2 Lotader AX8840 random copolymer, ethylene and 8% by weight of glycidyl methacrylate
as the third polymer (carrier polymer): P3 linear low-density polyethylene (LLDPE Sabic) M50002
as the absorber: A-1 bismuth oxide (Bi.sub.2O.sub.3) having a D.sub.50 of 1 m (5N Plus Lbeck GmbH) A-2 Iriotec 8825 (Merck KGaA) A-3 Iriotec 8208 (Merck KGaA)
as white pigment or filler: F-1 Kronos 2900, TiO.sub.2 rutile, Kronos F-2 Kronos 2220, TiO.sub.2 rutile, Kronos F-3 Fluorocarb ST, precipitated chalk, Central Technology UK as the matrix polymer: M-1 linear low-density polyethylene M500026 (Sabic)

(6) Process for the preparation of a laser marking absorber concentrate (LMAC, Table 1) and the comparative compounding concentrate (CCC, Table 1.1)

(7) A series of laser marking absorber concentrates LMAC 01-LMAC 06 and comparative compounding concentrates CCC 01-CCC 03 is prepared using a twin-screw extruder (Leistritz Mikro 27). The compositions of the LMACs and CCCs are shown in Tables 1 and 1.1 respectively. For LMAC 01-LMAC 06 and CCC 01-CCC 03, the screw speed is 250 revolutions per minute. The throughput for all compounds is 20 kg/h. In the case of LMAC 01-LMAC 06, the temperature is 260 C. in zone 1 and 260 C. in zone 10 and 280 C. at the extruder head. In the case of CCC 01, the temperature is 210 C. in zone 1 and 220 C. in zone 10, and 220 C. at the extruder head.

(8) TABLE-US-00002 TABLE 1 Composition of the laser marking absorber concentrates LMAC LMAC LMAC LMAC LMAC LMAC Compound 01 02 03 04 05 06 First P1.0 P1.2 P1.2 P1.2 P1.1 P1.0 polymer 20 30 30 20 50 30 Absorber A-1 A-1 A-1 A-1 A-1 A-1 57 20 35 57 25 20 White F-1 F-1 F-1 F-2 F-1 F-3 pigment/ 23 50 35 23 25 50 filler

(9) TABLE-US-00003 TABLE 1.1 Composition of the comparative compounding concentrates Compound CCC 01 CCC 02 CCC 03 Matrix polymer M-1 M-1 M-1 95 95 90 Absorber A-1 5 Absorber A-2 5 Absorber A-3 10
Process for the Preparation of the Laser Marking Concentrates (LMCs)

(10) A series of laser marking concentrates LMC 01-LMC 06 is prepared using a twin-screw extruder (Leistritz Mikro 27). The composition of the LMCs is shown in Table 2. The screw speed is 250 revolutions per minute and the throughput is 20 kg/h. In the case of LMC 01-LMC 06, the temperature is 260 C. in zone 1 and 280 C. in zone 10, and 280 C. at the extruder head.

(11) TABLE-US-00004 TABLE 2 Composition of the laser marking concentrates LMC LMC LMC LMC LMC LMC Compound 01 02 03 04 05 06 LMAC 01 70 LMAC 02 70 LMAC 03 70 LMAC 04 70 LMAC 05 50 LMAC 06 60 2nd P2.0 P2.0 P2.0 P2.2 P2.1 P2.1 polymer 2 2 2 1.5 5 2.5 3rd P3 P3 P3 P3 P3 P3 polymer 28 28 28 28.5 45 37.5
Process for the Preparation of the Laser Marking Diluted Concentrates (LMDCs)

(12) A series of laser marking diluted concentrates LMDC 01-LMDC 06 is prepared using a twin-screw extruder (Leistritz Mikro 27). The composition of the LMDCs is shown in Table 3. The screw speed is 250 revolutions per minute and the throughput is 15 kg/h. In the case of the diluted concentrates LMDC 01-LMDC 06, the temperature is 200 C. in zone 1 and 200 C. in zone 10, and likewise 200 C. at the extruder head.

(13) TABLE-US-00005 TABLE 3 Composition of the laser marking diluted concentrates LMDC LMDC LMDC LMDC LMDC LMDC 01 02 03 04 05 06 LMC 01 9 LMC 02 10 LMC 03 10 LMC 04 9 LMC 05 20 LMC 06 11 Matrix polymer M-1 M-1 M-1 M-1 M-1 M-1 91 90 90 91 80 89
Process for the Preparation of a Laser Marking Product (LMP)

(14) Laser marking products were prepared using a twin-screw extruder (Leistritz Mikro 27). The composition of the LMPs and the processing conditions are shown in Table 4. The screw speed was 250 revolutions per minute and the throughput was 15 kg/h. The temperature was 200 C. in zone 1 and 200 C. in zone 10, and 200 C. at the extruder head.

(15) TABLE-US-00006 TABLE 4 Composition of the laser marking products (LMPs) Compound LMP 01 LMP 02 LMP 03 LMP 04 LMP 05 LMP 06 LMDC 01 10 LMDC 02 10 LMDC 03 10 LMDC 04 10 LMDC 05 10 LMDC 06 10 Matrix M-1 M-1 M-1 M-1 M-1 M-1 polymer 90 90 90 90 90 90
Preparation of Laser Marking Samples

(16) Laser marking samples (LMSAs) are produced using injection moulding. The composition of the LMSAs and the processing conditions are shown in Tables 5a to 5c. The temperature in zone 1 is set at 190 C. for all samples. The temperature in zone 2, zone 3 and at the gate is 220 C. everywhere.

(17) TABLE-US-00007 TABLE 5a Composition and processing conditions of laser marking samples LMSA LMSA LMSA LMSA LMSA LMSA LMSA LMSA LMSA 01 02 03 04 05 06 07 08 09 LMP 01 100 50 25 LMP 02 100 50 25 LMP 03 100 50 25 Matrix M-1 M-1 M-1 M-1 M-1 M-1 polymer 50 75 50 75 50 75

(18) TABLE-US-00008 TABLE 5b Composition and processing conditions of laser marking samples LMSA LMSA LMSA LMSA LMSA LMSA LMSA LMSA LMSA 10 11 12 13 14 15 16 17 18 LMP4 100 50 25 LMP5 100 50 25 LMP6 100 50 25 Matrix M-1 M-1 M-1 M-1 M-1 M-1 polymer 50 75 50 75 50 75

(19) TABLE-US-00009 TABLE 5c Composition and processing conditions of laser marking samples LMSA LMSA LMSA LMSA LMSA LMSA LMSA LMSA LMSA 19 20 21 22 23 24 25 26 27 Matrix M-1 M-1 M-1 M-1 M-1 M-1 M-1 M-1 M-1 polymer 90 95 97.5 90 95 97.5 90 95 97.5 CCC 01 10 5 2.5 CCC 02 10 5 2.5 CCC 03 10 5 2.5

(20) Laser Marking Performance

(21) The laser marking assessments are carried out using a Trumpf VMc5 10.5 watt diode-pumped IR laser system. So-called evaluation matrices are marked. In such matrices, the marking speed (v [mm/sec]) and frequency (f [kHz]) are varied at a given power (p [%]), focal distance (z=0 [at the focus] above the sample) and line spacing. The evaluation matrices essentially indicate what contrast can be obtained at a particular marking speed while varying the laser parameters. An assessment of the laser marking performance with respect to contrast and marking speed, indicated by + and in a range from excellent (+++++) to poor (), is shown in Table 6.

(22) TABLE-US-00010 TABLE 6 Assessment of the laser marking performance of the LMSAs at a laser power of 99% and a line speed between 500 and 5000 mm/min Light absorber in percent Marking Sample Sample marking by weight.sup.1 performance Focal distance [+mm] 10 LMSA 01 matrix polymer: M1 0.5 +++++ LMSA 02 matrix polymer: M1 0.25 ++++ LMSA 03 matrix polymer: M1 0.125 +++ LMAS 04 matrix polymer: M1 0.5 +++++ LMSA 05 matrix polymer: M1 0.25 ++++ LMSA 06 matrix polymer: M1 0.125 +++ LMSA 07 matrix polymer: M1 0.5 +++++ LMSA 08 matrix polymer: M1 0.25 ++++ LMSA 09 matrix polymer: M1 0.125 +++ LMSA 10 matrix polymer: M1 0.5 +++++ LMSA 11 matrix polymer: M1 0.25 ++++ LMSA 12 matrix polymer: M1 0.125 +++ LMSA 13 matrix polymer: M1 0.5 +++++ LMSA 14 matrix polymer: M1 0.25 ++++ LMSA 15 matrix polymer: M1 0.125 +++ LMSA 16 matrix polymer: M1 0.5 ++++ LMSA 17 matrix polymer: M1 0.25 +++ LMSA 18 matrix polymer: M1 0.125 ++ LMSA 19 matrix polymer: M1 0.5 +++ LMSA 20 matrix polymer: M1 0.25 + LMSA 21 matrix polymer: M1 0.125 LMSA 22 matrix polymer: M1 0.5 ++ LMSA 23 matrix polymer: M1 0.25 + LMSA 24 matrix polymer: M1 0.125 LMSA 25 matrix polymer: M1 0.5 + LMSA 26 matrix polymer: M1 0.25 + LMSA 27 matrix polymer: M1 0.125 .sup.1based on the total amount of laser markable composition.