Use of crystal water-free Fe(II) compounds as radiation absorbers

Abstract

A method of using an absorber of electromagnetic radiation, includes absorbing electromagnetic radiation with the absorber finely distributed or dissolved in a carrier material. The absorber is a crystal water-free iron(II) orthophosphate of the general formula Fe.sub.3(PO.sub.4).sub.2 or crystal water-free iron(II) metal orthophosphate, iron(II) metal phosphonate, iron(II) metal pyrophosphate or iron(II) metal metaphosphate of the general formula Fe.sub.aMet.sub.b(PO.sub.c).sub.d, where a is a number from 1 to 5, b is a number from >0 to 5, c is a number from 2.5 to 5, d is a number from 0.5 to 3 and Met represents one or more metals selected from the group consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, the transition metals (d block), the metals and semimetals of the third, fourth and fifth main groups, and the lanthanoids or combinations of the above mentioned phosphates as absorbers of electromagnetic radiation.

Claims

1. A method of using an absorber of electromagnetic radiation comprising: absorbing electromagnetic radiation with the absorber finely distributed or dissolved in a carrier material, wherein the absorber is: crystal water-free iron(II) orthophosphate of the general formula Fe.sub.3(PO.sub.4).sub.2 and being selected from compounds which have a crystal structure comprising transition metal complexes of iron in which the complex does not have an inversion center relative to the central atom, or crystal water-free iron(II) metal orthophosphate, iron(II) metal phosphonate, iron(II) metal pyrophosphate or iron(II) metal metaphosphate of the general formula Fe.sub.aMet.sub.b(PO.sub.c).sub.d, where a is a number from 1 to 5, b is a number from >0 to 5, c is a number from 2.5 to 5, d is a number from 0.5 to 3 and Met represents one or more metals selected from the group consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, the transition metals (d block), the metals and semimetals of the third, fourth and fifth main groups, and the lanthanoids or combinations of the above mentioned phosphates, and being selected from compounds which have a crystal structure comprising transition metal complexes of iron in which the complex does not have an inversion center relative to the central atom, and wherein the carrier material contains the absorber in a quantity such that it absorbs infrared radiation where the wavelength is at least in the region from 780 nm to 1400 nm more strongly than the same carrier material which does not contain the absorber.

2. The method according to claim 1, wherein the absorber is present in the carrier material in a concentration of 1 ppm to 20% by weight based on the total weight of the carrier material with any aggregates it contains including the absorber.

3. The method according to claim 1, wherein the carrier material is selected from the group consisting of thermoplastic and duroplastic polymers, oxidic ceramics, non-oxidic ceramics, glasses, hot-melt adhesives, dyes, varnishes, silicons, cardboards, papers, pulps and celluloses.

4. The method according to claim 1, wherein the carrier material is a thermoplastic polymer selected from the group consisting of polyvinyl butyral (PVB), polypropylene (PP), polyethylene (PE), polyamide (PA), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyphenylene oxide, polyacetal, polymethacrylate, polyoxymethylene, polyvinyl acetal, polystyrene, acryl butadien styrene (ABS), acrylonitrile styrene acrylate (ASA), polycarbonate, polyethersulfone, polysulfonate, polytetrafluoroethylene, polyurea, formaldehyde resins, melamine resins, polyetherketone, polyvinyl chloride, polylactide, polysiloxane, phenol resins, epoxide resins, poly(imide), bismaleimide-triazine, and thermoplastic polyurethane, and copolymers and/or mixtures of the polymers mentioned above.

5. The method according to claim 1, wherein the absorber has an average particle size (d50 value) between 0.01 μm and 50 μm.

6. The method according to claim 1, wherein the absorber is crystal water-free iron(II) orthophosphate of the general formula Fe.sub.3(PO.sub.4).sub.2 and has graftonite crystal structure.

7. The method according to claim 1, wherein the carrier material containing the absorber is manufactured into products that comprise the carrier material, the products being selected from the group consisting of: packaging material for commercial products, whereby the carrier material is a thermoplastic or duroplastic polymer; window panes, whereby the carrier material is a transparent thermoplastic polymer, transparent duroplastic polymer or glass; preforms which are provided and designed for further processing into end products; and end products made of thermoplastic polymers which are manufactured in a thermal reshaping procedure.

8. The method according to claim 1, wherein the carrier material is a thermoplastic or duroplastic material, hot-melt adhesive, dye, varnish, or silicone, wherein the absorber acts as a heating accelerator, polymerization accelerator, or cross-linking accelerator within the carrier material when irradiated with electromagnetic radiation.

9. The method according to claim 1, wherein the step of absorbing electromagnetic radiation involves laser marking, laser inscription, laser welding and/or polymer joining.

10. The method according to claim 1, wherein the step of absorbing electromagnetic radiation involves infrared radiation in the manufacture of electrically conductive metal structures.

11. The method according to claim 1, wherein maximum absorption of the absorber at a wavelength is in the region of 200 nm to 12,000 nm with the absorbed radiation comprising laser radiation and/or non-laser radiation.

Description

(1) The invention is now explained further using examples of manufacturing for absorbers according to the invention and using examples of uses according to the invention and the attached figures.

(2) FIG. 1 shows the x-ray diffractogram of crystal water-free Fe.sub.2P.sub.2O.sub.7 manufactured in accordance with the invention in line with manufacturing example 1.

(3) FIG. 2 shows the x-ray diffractogram of a phase mixture of crystal water-free Mg.sub.1.5Fe.sub.1.5(PO.sub.4).sub.2 and Fe.sub.3(PO.sub.4).sub.2 manufactured in accordance with the invention in line with manufacturing example 2.

(4) FIG. 3 shows the x-ray diffractogram of crystal water-free Fe.sub.3(PO.sub.4).sub.2 manufactured in accordance with the invention in line with manufacturing example 3.

(5) FIG. 4 shows the x-ray diffractogram of crystal water-free KFe(PO.sub.4) manufactured in accordance with the invention in line with manufacturing example 4.

(6) FIG. 5 shows the x-ray diffractogram of crystal water-free KFe.sub.0.90Zn.sub.0.10(PO.sub.4) manufactured in accordance with the invention in line with manufacturing example 5.

(7) FIG. 6 shows the x-ray diffractogram of crystal water-free KFe.sub.0.75Zn.sub.0.25(PO.sub.4) manufactured in accordance with the invention in line with manufacturing example 6.

(8) FIG. 7 shows the x-ray diffractogram of crystal water-free KFe.sub.0.75Mn.sub.0.25(PO.sub.4) manufactured in accordance with the invention in line with manufacturing example 7.

(9) FIG. 8 shows the x-ray diffractogram of crystal water-free BaFeP.sub.2O.sub.7 manufactured in accordance with the invention in line with manufacturing example 8.

EXAMPLES

(10) X-Ray Diffractometry (XRD)

(11) Of the products manufactured according to the examples below, x-ray diffraction measurements (XRD) are taken using a D8 Advance A25-type diffractometer (Bruker) and CuKα radiation.

(12) The products and their crystal structures were identified on the basis of corresponding reference diffractograms (Powder Diffraction Files; PDF) from the ICDD (International Centre for Diffraction Data), previously JCPDS (Joint Committee on Powder Diffraction Standards) database. If no PDF cards were available for the products manufactured, PDF cards for isotype compounds were used (=compounds of the same structural type).

(13) Elementary Analysis

(14) Elementary analyses were carried out by means of x-ray fluorescence analysis (XRF) using an Axios FAST spectrometer (PANalytical) in order to determine and confirm the stoichiometries of the products manufactured.

Manufacturing Example 1

Crystal Water-Free Fe.SUB.2.P.SUB.2.O.SUB.7

(15) A suspension of

(16) i) 35.5 kg iron(III) oxide-hydroxide [FeO(OH) or Fe.sub.2O.sub.3 1H.sub.2O],

(17) ii) 16.5 kg 98% phosphonic acid [H.sub.3PO.sub.3],

(18) iii) 26.5 kg 75% phosphoric acid [H.sub.3PO.sub.4] and

(19) LA: 220 kg water

(20) was spray granulated. The granulate obtained in this way was temperature treated in a rotary kiln for an average residence time of 4 h in a form gas atmosphere (5% by volume H.sub.2 in N.sub.2) at 700° C. An almost colourless to slightly pink product is obtained. The x-ray diffractogram (XRD) of the product is shown in FIG. 1. The product was identified using PDF card 01-072-1516.

Manufacturing Example 2

Phase Mixture of Crystal Water-Free Mg.SUB.1.5.Fe.SUB.1.5.(PO.SUB.4.).SUB.2 .and Fe.SUB.3.(PO.SUB.4.).SUB.2

(21) A suspension of

(22) i) 8.45 kg iron(III) oxide-hydroxide [FeO(OH) or Fe.sub.2O.sub.3 1H.sub.2O],

(23) ii) 7.95 kg 98% phosphonic acid [H.sub.3PO.sub.3],

(24) iii) 19.6 kg iron(III) phosphate dihydrate [FePO.sub.4 2H.sub.2O],

(25) iv) 8.43 kg magnesium carbonate [MgCO.sub.3] and

(26) LA: 160 kg water

(27) was spray granulated. The granulate obtained in this way was temperature treated in a rotary kiln for an average residence time of 3 h in a form gas atmosphere (5% by volume H.sub.2 in N.sub.2) at 750° C.

(28) An almost colourless product is obtained. The x-ray diffractogram (XRD) of the product is shown in FIG. 2. The product was identified using the PDF cards as a phase mixture of a main phase Mg.sub.1.5Fe.sub.1.5(PO.sub.4).sub.2 (PDF card 01-071-6793) and a subsidiary phase Fe.sub.3(PO.sub.4).sub.2 (PDF card 00-49-1087).

Manufacturing Example 3

Crystal Water-Free Fe.SUB.3.(PO.SUB.4.).SUB.2

(29) A suspension of

(30) i) 21.75 kg iron(III) oxide-hydroxide [FeO(OH) or Fe.sub.2O.sub.3 1H.sub.2O],

(31) ii) 12.15 kg 98% phosphonic acid [H.sub.3PO.sub.3],

(32) iii) 10.3 kg iron(III) phosphate dihydrate [FePO.sub.4 2H.sub.2O] and

(33) LA: 140 kg water

(34) was spray granulated. The granulate obtained in this way was temperature treated in a rotary kiln for an average residence time of 90 minutes in a form gas atmosphere (5% by volume H.sub.2 in N.sub.2) at 750° C. An almost colourless product is obtained. The x-ray diffractogram (XRD) of the product is shown in FIG. 3. The product crystallises in the graftonite structure and was identified using PDF card 00-49-1087. The product was ground such that 50% by weight of the product had a particle size of less than 3 μm.

Manufacturing Example 4

Manufacture of Crystal Water-Free KFe(PO.SUB.4.)

(35) A suspension of

(36) i) 11.80 kg iron(III) oxide-hydroxide [FeO(OH) or Fe.sub.2O.sub.3 1H.sub.2O],

(37) ii) 10.70 kg 98% phosphonic acid [H.sub.3PO.sub.3],

(38) iii) 24.8 kg iron(III) phosphate dihydrate [FePO.sub.4 2H.sub.2O]

(39) IV) 29.8 kg 50% lye [KOH]

(40) V) 1.0 kg 75% phosphoric acid [H.sub.3PO.sub.4] and

(41) LA: 110 kg water

(42) was spray granulated. The granulate obtained in this way was temperature treated in a rotary kiln for an average residence time of 3 h in a form gas atmosphere (5% by volume H.sub.2 in N.sub.2) at 650° C. A pale light green product is obtained. The x-ray diffractogram (XRD) of the product is shown in FIG. 4. The product was identified using PDF card 01-076-4615.

Manufacturing Example 5

Crystal Water-Free KFe.SUB.0.90.Zn.SUB.0.10.(PO.SUB.4.)

(43) A suspension of

(44) i) 10.60 kg iron(III) oxide-hydroxide [FeO(OH) or Fe.sub.2O.sub.3 1H.sub.2O],

(45) ii) 9.65 kg 98% phosphonic acid [H.sub.3PO.sub.3],

(46) iii) 22.30 kg iron(III) phosphate dihydrate [FePO.sub.4 2H.sub.2O]

(47) IV) 2.15 kg zinc oxide [ZnO]

(48) IV) 29.8 kg 50% lye [KOH]

(49) V) 4.15 kg 75% phosphoric acid [H.sub.3PO.sub.4] and

(50) LA: 120 kg water

(51) was spray granulated. The granulate obtained in this way was temperature treated in a rotary kiln for an average residence time of 2 h in a form gas atmosphere (5% by volume H.sub.2 in N.sub.2) at 600° C. An light grey product is obtained. The x-ray diffractogram (XRD) of the product is shown in FIG. 5. The product is a new structure type which appears to be closely linked to the KFe(PO.sub.4) structure according to PDF card 01-076-4615.

Manufacturing Example 6

Crystal Water-Free KFe.SUB.0.75.Zn.SUB.0.25.(PO.SUB.4.)

(52) A suspension of

(53) i) 8.85 kg iron(III) oxide-hydroxide [FeO(OH) or Fe.sub.2O.sub.3 1H.sub.2O],

(54) ii) 8.05 kg 98% phosphonic acid [H.sub.3PO.sub.3],

(55) iii) 18.60 kg iron(III) phosphate dihydrate [FePO.sub.4 2H.sub.2O]

(56) IV) 5.40 kg zinc oxide [ZnO]

(57) IV) 29.8 kg 50% lye [KOH]

(58) V) 9.30 kg 75% phosphoric acid [H.sub.3PO.sub.4] and

(59) LA: 120 kg water

(60) was spray granulated. The granulate obtained in this way was temperature treated in a rotary kiln for an average residence time of 2 h in a form gas atmosphere (5% by volume H.sub.2 in N.sub.2) at 600° C. A light grey product is obtained. The x-ray diffractogram (XRD) of the product is shown in FIG. 6. The product is not known from the literature. It crystallises in an isotype manner to form KZn(PO.sub.4) according to PDF card 01-081-1034.

Manufacturing Example 7

Crystal Water-Free KFe.SUB.0.75.Mn.SUB.0.25.(PO.SUB.4.)

(61) A suspension of

(62) i) 8.85 kg iron(III) oxide-hydroxide [FeO(OH) or Fe.sub.2O.sub.3 1H.sub.2O],

(63) ii) 8.05 kg 98% phosphonic acid [H.sub.3PO.sub.3],

(64) iii) 18.60 kg iron(III) phosphate dihydrate [FePO.sub.4 2H.sub.2O]

(65) IV) 8.85 kg manganese carbonate hydrate [MnCO.sub.3 H.sub.2O]

(66) IV) 29.8 kg 50% lye [KOH]

(67) V) 9.30 kg 75% phosphoric acid [H.sub.3PO.sub.4] and

(68) LA: 140 kg water

(69) was spray granulated. The granulate obtained in this way was temperature treated in a rotary kiln for an average residence time of 2 h in a form gas atmosphere (5% by volume H.sub.2 in N.sub.2) at 600° C. A light grey product is obtained. The x-ray diffractogram (XRD) of the product is shown in FIG. 7.

(70) The product is not known from the literature. It crystallises in an isotype manner to form KFe(PO.sub.4) according to PDF card 01-076-4615.

Manufacturing Example 8

Crystal Water-Free BaFeP.SUB.2.O.SUB.7

(71) A suspension of

(72) i) 8.70 kg iron(III) oxide-hydroxide [FeO(OH) or Fe.sub.2O.sub.3 1H.sub.2O],

(73) ii) 8.20 kg 98% phosphonic acid [H.sub.3PO.sub.3],

(74) iii) 19.05 kg iron(III) phosphate dihydrate [FePO.sub.4 2H.sub.2O]

(75) IV) 63.09 kg barium hydroxide octahydrate [Ba(OH).sub.2 8H.sub.2O]

(76) V) 26.15 kg 75% phosphoric acid [H.sub.3PO.sub.4] and

(77) LA: 250 kg water

(78) was spray granulated. The granulate obtained in this way was temperature treated in a rotary kiln for an average residence time of 4 h in a form gas atmosphere (5% by volume H.sub.2 in N.sub.2) at 800° C. A light grey product is obtained. The x-ray diffractogram (XRD) of the product is shown in FIG. 8. The product crystallises in an isotype manner to form BaCoP.sub.2O.sub.7 according to PDF card 01-084-1833.

Example Use 1

Laser Welding)

(79) Two percent by weight of the absorber Fe.sub.3(PO.sub.4).sub.2 according to manufacturing example 3 was evenly distributed in a polyethylene (Lupolen 1800S by BASF) using an extruder (ZSK18-type by Coperion GmbH). Plates of 3 cm×4 cm×3 mm were then prepared from the extrudate. A plate with the same dimensions was then manufactured but without the addition of the absorber. The plate without the absorber was placed over the plate with the absorber and the plates were then welded using an Nd:YAG laser with a wavelength of 1064 nm.

Example Use 2

LDS

(80) The absorber material iron II magnesium phosphate according to the invention, a phase mixture of Mg.sub.1.5Fe.sub.1.5(PO.sub.4).sub.2 and Fe.sub.3(PO.sub.4).sub.2 according to manufacturing example 2 were mixed with 1% by weight sodium dihydrogen pyrophosphate. Five percent by weight of the mixture was then worked into a polyamide 6.6 (Ultramid™ by BASF) using an extruder (ZSK18-type by Coperion GmbH) and a granulate manufactured. The granulate was then further processed to form plates of 3 cm×4 cm×3 mm. The plates were irradiated with an Nd:YAG laser (Trumpf) at a wavelength of 1064 nm and antennae structures generated which could then be used to receive electromagnetic radiation.

Example Use 3

Heating Rate

(81) Five percent by weight of the absorber K(Fe.sub.0.75Zn.sub.0.25)PO.sub.4 according to manufacturing example 6 was evenly distributed in a polypropylene (HE125MO by Borealis) using an extruder (ZSK18-type by Coperion GmbH). Plates of 3 cm×4 cm×3 cm were manufactured from the extrudate and were then radiated with a conventional IR lamp (red light lamp). The same polymer body although without the absorber additive was radiated in the same way for comparison purposes. The temperature of the body over time was recorded during the radiation. In the polymer body with the additive consisting of the absorber according to the invention a temperature of 77° C. was reached after one minute while in the polymer body without the addition of the absorber the temperature of 77° C. was only reached after five minutes of radiation. The temperature recording curve for the polymer body with the addition of the absorber according to the invention had almost twice as fast a heating rate than the temperature recording curve for the polymer body without the addition of the absorber over the entire time period.

Example Use 4

Laser Inscription/Laser Marking)

(82) Two percent by weight of the absorber according to the invention KFe(PO.sub.4) according to manufacturing example 4 was evenly worked into a polyethylene (Lupolen 1800S by BASF) using an extruder (ZSK18-type by Coperion GmbH). Plates of 3 cm×4 cm×3 mm were then prepared from the extrudate. Markings were then made on the surface of the plates by irradiation with an Nd:YAG laser with a wavelength of 1064 nm. The same polymer plates just without the absorber additive were laser marked in the same way for comparison purposes. In the polymer plates with absorbers according to the invention the markings were clearly visible even with a laser output of 1 watt and a frequency of 6000 Hz. There were no visible markings on the irradiated reference plate which did not contain absorbers under the same conditions.

Example Use 5

Heating of Preforms Using IR Radiation

(83) Preforms were manufactured from a master batch of polyethylene terephthalate (PET) with 500 ppm K(Fe.sub.0.75Zn.sub.0.25)PO.sub.4 according to manufacturing example 6 as they would be for the manufacture of drinks bottles. The same preforms but without the addition of absorber were also manufactured for comparison purposes. The preforms were heated using IR halogen heaters until glass transition point of the polymers. The energy required for heating was approximately 15% lower in the preforms with the added absorber and the time needed for the required irradiation was approximately 20% shorter than in the case of the preforms without absorber.

Example Use 6

Cross-Linking of Silicon

(84) A non-cross-linked silicon mass was mixed with 0.05% by weight crystal water-free Fe.sub.3(PO.sub.4).sub.2 with a graftonite crystal structure according to manufacturing example 3 and then a conventional peroxide cross-linking agent was added. The silicon mass was then extensively heated using laser light at a wavelength of 980 nm using a VCSEL laser (Phillips). The same silicon mass not containing any absorber was treated in the same way for comparison purposes. The cross-linking of the silicon containing the absorber according to the invention was already complete after 110 seconds while the cross-linking of the silicon without the absorber took 120 seconds. The addition of small quantities of absorber according to the invention therefore meant that the energy required for cross-linking and therefore also the cross-linking time were able to be reduced.

Example Use 7

Laser Welding

(85) Four percent by weight crystal water-free Fe.sub.3(PO.sub.4).sub.2 with a graftonite crystal structure according to manufacturing example 3 was worked evenly into a polyamide 6.6 (Ultramid™ by BASF) using an extruder (ZSK18-type by Coperion GmbH) and from this a moulded part for the automotive industry was manufactured which is used as a tail light in passenger vehicles. A further component which is to be connected (welded) to the above mentioned component was manufactured from the same material but without an absorber. The two components were then welded using a conventional diode laser with a wavelength of 940 nm. For comparison purposes, an attempt was made to weld corresponding components neither of which contained absorbers, but this was not possible without destruction.