US20200140696A1 - Low reflectance powder coating compositions - Google Patents
Low reflectance powder coating compositions Download PDFInfo
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- US20200140696A1 US20200140696A1 US16/556,574 US201916556574A US2020140696A1 US 20200140696 A1 US20200140696 A1 US 20200140696A1 US 201916556574 A US201916556574 A US 201916556574A US 2020140696 A1 US2020140696 A1 US 2020140696A1
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- United States
- Prior art keywords
- coating composition
- acrylic
- powder
- powder coating
- resin
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000000843 powder Substances 0.000 title claims abstract description 69
- 239000008199 coating composition Substances 0.000 title claims abstract description 35
- 125000002887 hydroxy group Chemical group [H]O* 0.000 claims abstract description 45
- 239000011347 resin Substances 0.000 claims abstract description 39
- 229920005989 resin Polymers 0.000 claims abstract description 39
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims abstract description 36
- 239000004971 Cross linker Substances 0.000 claims abstract description 10
- 229920000178 Acrylic resin Polymers 0.000 claims abstract description 9
- 239000004925 Acrylic resin Substances 0.000 claims abstract description 9
- 239000000945 filler Substances 0.000 claims abstract description 7
- 238000000576 coating method Methods 0.000 claims description 12
- 239000000758 substrate Substances 0.000 claims description 12
- 239000012948 isocyanate Substances 0.000 claims description 10
- 229910052882 wollastonite Inorganic materials 0.000 claims description 10
- 239000010456 wollastonite Substances 0.000 claims description 10
- 229920000058 polyacrylate Polymers 0.000 claims description 9
- 239000007787 solid Substances 0.000 claims description 7
- -1 isocyanate compound Chemical class 0.000 claims description 6
- IQPQWNKOIGAROB-UHFFFAOYSA-N isocyanate group Chemical group [N-]=C=O IQPQWNKOIGAROB-UHFFFAOYSA-N 0.000 claims description 5
- 239000011248 coating agent Substances 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 3
- 229910052739 hydrogen Inorganic materials 0.000 claims description 3
- 239000001257 hydrogen Substances 0.000 claims description 3
- 238000000034 method Methods 0.000 claims description 3
- 229920000642 polymer Polymers 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 14
- 150000002513 isocyanates Chemical class 0.000 description 7
- 239000000049 pigment Substances 0.000 description 7
- 239000005056 polyisocyanate Substances 0.000 description 7
- 229920001228 polyisocyanate Polymers 0.000 description 7
- 239000000178 monomer Substances 0.000 description 5
- 239000003795 chemical substances by application Substances 0.000 description 4
- 125000005442 diisocyanate group Chemical group 0.000 description 4
- NIMLQBUJDJZYEJ-UHFFFAOYSA-N isophorone diisocyanate Chemical compound CC1(C)CC(N=C=O)CC(C)(CN=C=O)C1 NIMLQBUJDJZYEJ-UHFFFAOYSA-N 0.000 description 4
- 239000005058 Isophorone diisocyanate Substances 0.000 description 3
- 239000006096 absorbing agent Substances 0.000 description 3
- JBKVHLHDHHXQEQ-UHFFFAOYSA-N epsilon-caprolactam Chemical compound O=C1CCCCCN1 JBKVHLHDHHXQEQ-UHFFFAOYSA-N 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 3
- 239000004611 light stabiliser Substances 0.000 description 3
- PCHXZXKMYCGVFA-UHFFFAOYSA-N 1,3-diazetidine-2,4-dione Chemical compound O=C1NC(=O)N1 PCHXZXKMYCGVFA-UHFFFAOYSA-N 0.000 description 2
- UPMLOUAZCHDJJD-UHFFFAOYSA-N 4,4'-Diphenylmethane Diisocyanate Chemical compound C1=CC(N=C=O)=CC=C1CC1=CC=C(N=C=O)C=C1 UPMLOUAZCHDJJD-UHFFFAOYSA-N 0.000 description 2
- 239000004606 Fillers/Extenders Substances 0.000 description 2
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 150000001412 amines Chemical class 0.000 description 2
- ISAOCJYIOMOJEB-UHFFFAOYSA-N benzoin Chemical compound C=1C=CC=CC=1C(O)C(=O)C1=CC=CC=C1 ISAOCJYIOMOJEB-UHFFFAOYSA-N 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
- 239000006229 carbon black Substances 0.000 description 2
- 239000013043 chemical agent Substances 0.000 description 2
- 235000013980 iron oxide Nutrition 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000004094 surface-active agent Substances 0.000 description 2
- DTGKSKDOIYIVQL-WEDXCCLWSA-N (+)-borneol Chemical group C1C[C@@]2(C)[C@@H](O)C[C@@H]1C2(C)C DTGKSKDOIYIVQL-WEDXCCLWSA-N 0.000 description 1
- VNMOIBZLSJDQEO-UHFFFAOYSA-N 1,10-diisocyanatodecane Chemical compound O=C=NCCCCCCCCCCN=C=O VNMOIBZLSJDQEO-UHFFFAOYSA-N 0.000 description 1
- AZYRZNIYJDKRHO-UHFFFAOYSA-N 1,3-bis(2-isocyanatopropan-2-yl)benzene Chemical compound O=C=NC(C)(C)C1=CC=CC(C(C)(C)N=C=O)=C1 AZYRZNIYJDKRHO-UHFFFAOYSA-N 0.000 description 1
- AGJCSCSSMFRMFQ-UHFFFAOYSA-N 1,4-bis(2-isocyanatopropan-2-yl)benzene Chemical compound O=C=NC(C)(C)C1=CC=C(C(C)(C)N=C=O)C=C1 AGJCSCSSMFRMFQ-UHFFFAOYSA-N 0.000 description 1
- ROHUXHMNZLHBSF-UHFFFAOYSA-N 1,4-bis(isocyanatomethyl)cyclohexane Chemical compound O=C=NCC1CCC(CN=C=O)CC1 ROHUXHMNZLHBSF-UHFFFAOYSA-N 0.000 description 1
- OVBFMUAFNIIQAL-UHFFFAOYSA-N 1,4-diisocyanatobutane Chemical compound O=C=NCCCCN=C=O OVBFMUAFNIIQAL-UHFFFAOYSA-N 0.000 description 1
- CDMDQYCEEKCBGR-UHFFFAOYSA-N 1,4-diisocyanatocyclohexane Chemical compound O=C=NC1CCC(N=C=O)CC1 CDMDQYCEEKCBGR-UHFFFAOYSA-N 0.000 description 1
- SBJCUZQNHOLYMD-UHFFFAOYSA-N 1,5-Naphthalene diisocyanate Chemical compound C1=CC=C2C(N=C=O)=CC=CC2=C1N=C=O SBJCUZQNHOLYMD-UHFFFAOYSA-N 0.000 description 1
- OUJCKESIGPLCRN-UHFFFAOYSA-N 1,5-diisocyanato-2,2-dimethylpentane Chemical compound O=C=NCC(C)(C)CCCN=C=O OUJCKESIGPLCRN-UHFFFAOYSA-N 0.000 description 1
- AHBNSOZREBSAMG-UHFFFAOYSA-N 1,5-diisocyanato-2-methylpentane Chemical compound O=C=NCC(C)CCCN=C=O AHBNSOZREBSAMG-UHFFFAOYSA-N 0.000 description 1
- QGLRLXLDMZCFBP-UHFFFAOYSA-N 1,6-diisocyanato-2,4,4-trimethylhexane Chemical compound O=C=NCC(C)CC(C)(C)CCN=C=O QGLRLXLDMZCFBP-UHFFFAOYSA-N 0.000 description 1
- ZDKYYMRLZONTFK-UHFFFAOYSA-N 3,4-bis(isocyanatomethyl)bicyclo[2.2.1]heptane Chemical compound C1CC2(CN=C=O)C(CN=C=O)CC1C2 ZDKYYMRLZONTFK-UHFFFAOYSA-N 0.000 description 1
- JLBJTVDPSNHSKJ-UHFFFAOYSA-N 4-Methylstyrene Chemical compound CC1=CC=C(C=C)C=C1 JLBJTVDPSNHSKJ-UHFFFAOYSA-N 0.000 description 1
- MGYGFNQQGAQEON-UHFFFAOYSA-N 4-tolyl isocyanate Chemical compound CC1=CC=C(N=C=O)C=C1 MGYGFNQQGAQEON-UHFFFAOYSA-N 0.000 description 1
- PJMDLNIAGSYXLA-UHFFFAOYSA-N 6-iminooxadiazine-4,5-dione Chemical compound N=C1ON=NC(=O)C1=O PJMDLNIAGSYXLA-UHFFFAOYSA-N 0.000 description 1
- GAWIXWVDTYZWAW-UHFFFAOYSA-N C[CH]O Chemical group C[CH]O GAWIXWVDTYZWAW-UHFFFAOYSA-N 0.000 description 1
- 208000031968 Cadaver Diseases 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229920013685 Estron Polymers 0.000 description 1
- DNXHEGUUPJUMQT-CBZIJGRNSA-N Estrone Chemical compound OC1=CC=C2[C@H]3CC[C@](C)(C(CC4)=O)[C@@H]4[C@@H]3CCC2=C1 DNXHEGUUPJUMQT-CBZIJGRNSA-N 0.000 description 1
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-M Methacrylate Chemical compound CC(=C)C([O-])=O CERQOIWHTDAKMF-UHFFFAOYSA-M 0.000 description 1
- 235000000126 Styrax benzoin Nutrition 0.000 description 1
- 244000028419 Styrax benzoin Species 0.000 description 1
- 235000008411 Sumatra benzointree Nutrition 0.000 description 1
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 1
- 150000001253 acrylic acids Chemical class 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 125000001931 aliphatic group Chemical group 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 239000002216 antistatic agent Substances 0.000 description 1
- 229960002130 benzoin Drugs 0.000 description 1
- 125000001797 benzyl group Chemical group [H]C1=C([H])C([H])=C(C([H])=C1[H])C([H])([H])* 0.000 description 1
- OHJMTUPIZMNBFR-UHFFFAOYSA-N biuret Chemical compound NC(=O)NC(N)=O OHJMTUPIZMNBFR-UHFFFAOYSA-N 0.000 description 1
- 125000000484 butyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000002575 chemical warfare agent Substances 0.000 description 1
- 238000003776 cleavage reaction Methods 0.000 description 1
- 239000003431 cross linking reagent Substances 0.000 description 1
- 125000000113 cyclohexyl group Chemical group [H]C1([H])C([H])([H])C([H])([H])C([H])(*)C([H])([H])C1([H])[H] 0.000 description 1
- 125000002704 decyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- KORSJDCBLAPZEQ-UHFFFAOYSA-N dicyclohexylmethane-4,4'-diisocyanate Chemical compound C1CC(N=C=O)CCC1CC1CCC(N=C=O)CC1 KORSJDCBLAPZEQ-UHFFFAOYSA-N 0.000 description 1
- 238000007590 electrostatic spraying Methods 0.000 description 1
- 229960003399 estrone Drugs 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 235000019382 gum benzoic Nutrition 0.000 description 1
- RRAMGCGOFNQTLD-UHFFFAOYSA-N hexamethylene diisocyanate Chemical compound O=C=NCCCCCCN=C=O RRAMGCGOFNQTLD-UHFFFAOYSA-N 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 1
- ZFSLODLOARCGLH-UHFFFAOYSA-N isocyanuric acid Chemical compound OC1=NC(O)=NC(O)=N1 ZFSLODLOARCGLH-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 125000000325 methylidene group Chemical group [H]C([H])=* 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- WHIVNJATOVLWBW-UHFFFAOYSA-N n-butan-2-ylidenehydroxylamine Chemical compound CCC(C)=NO WHIVNJATOVLWBW-UHFFFAOYSA-N 0.000 description 1
- 125000001971 neopentyl group Chemical group [H]C([*])([H])C(C([H])([H])[H])(C([H])([H])[H])C([H])([H])[H] 0.000 description 1
- 239000012860 organic pigment Substances 0.000 description 1
- HXSACZWWBYWLIS-UHFFFAOYSA-N oxadiazine-4,5,6-trione Chemical group O=C1ON=NC(=O)C1=O HXSACZWWBYWLIS-UHFFFAOYSA-N 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 150000002989 phenols Chemical class 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 239000002952 polymeric resin Substances 0.000 description 1
- 230000000379 polymerizing effect Effects 0.000 description 1
- 125000001436 propyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 230000007017 scission Effects 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- RUELTTOHQODFPA-UHFFFAOYSA-N toluene 2,6-diisocyanate Chemical compound CC1=C(N=C=O)C=CC=C1N=C=O RUELTTOHQODFPA-UHFFFAOYSA-N 0.000 description 1
- 125000004417 unsaturated alkyl group Chemical group 0.000 description 1
- AVWRKZWQTYIKIY-UHFFFAOYSA-N urea-1-carboxylic acid Chemical compound NC(=O)NC(O)=O AVWRKZWQTYIKIY-UHFFFAOYSA-N 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
- C09D5/03—Powdery paints
- C09D5/032—Powdery paints characterised by a special effect of the produced film, e.g. wrinkle, pearlescence, matt finish
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
- C09D5/03—Powdery paints
- C09D5/033—Powdery paints characterised by the additives
- C09D5/035—Coloring agents, e.g. pigments
Definitions
- Very low gloss powder coatings are desirable for a variety of uses including automotive interior parts, wheel rims, bumpers, firearms, and military applications and other articles where low reflectance is desired.
- a particular requirement of some military applications involves resistance to penetration by chemical warfare agents according to military specifications such as MIL-PRF-32348.
- MIL-PRF-32348 chemical warfare agents according to military specifications
- it is useful to provide a coating composition which when applied to a substrate and cured will have a 60° gloss less than 1 and an 85° gloss less than 7, for example, 3.5 or less.
- This invention therefore relates to a low gloss powder coating composition
- a low gloss powder coating composition comprising:
- One aspect of this invention involves the selection of two different hydroxyl functional acrylic powder resins having varying hydroxyl values.
- the production of acrylic polymers of a given hydroxyl number is well known within the art.
- the hydroxyl functional acrylic polymers of this invention are obtained in a customary manner, for example, by polymerizing at least one hydroxyl functional monomer, typically a hydroxyl functional (meth)acrylate such as hydroxyethyl or hydroxypropyl (meth)acrylate, along with other copolymerizable unsaturated monomers.
- Representative copolymerizable monomers include vinyl compounds such as styrene, methylstyrene, vinyl acetate, and the unsaturated alkyl esters of (meth)acrylic acids.
- Suitable alkyl (meth)acrylate monomers include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, propyl (meth)acrylate, 2-ethyl hexyl (meth)acrylate, cyclohexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, neopentyl (meth)acrylate, and 1-adamatyl methacrylate.
- any given hydroxyl value can be selected.
- the polymers can be formulated to any useful glass transition temperature. For some applications it is useful to have a Tg of at least 35° C., and sometimes at least 40° C. for each of the hydroxy functional acrylic resins. For some applications it is useful to have the resin with the higher hydroxyl number have a Tg of at least 45° C. or higher to provide ever greater resistance to chemical agents.
- a first hydroxyl functional acrylic powder resin will be produced having a hydroxyl value of at least about 180, and a second hydroxyl functional acrylic polymer resin will be produced having a hydroxyl value between about 45 and about 80. These resins are then combined with a suitable crosslinking agent reactive with hydroxyl groups, such as a blocked isocyanate or uretdione, to provide the powder coating composition.
- the first acrylic powder resin will have a hydroxyl value between about 180 and about 300, and for some embodiments of this invention it is useful for the second acrylic powder resin to have a hydroxyl value between about 45 and 60, for some embodiments about 60.
- the first acrylic powder resin will have a hydroxyl value that is at least about 150 higher than the hydroxyl value of the second acrylic powder resin, for example, at least about 150 to about 240 higher, further for example, at least about 170 to about 190 higher.
- first acrylic powder resin For those applications requiring resistance to chemical agents it is often useful to provide a weight ratio of the first acrylic powder resin to the second acrylic powder resin greater than 0.5, for example, greater than 0.8, further for example about 1.0.
- first acrylic powder resin for the combination of the first acrylic powder resin and the second acrylic powder resin, between about 33.3 weight percent and 66.6 weight percent of the total amount of hydroxy functional acrylic resin would be the first acrylic powder resin.
- second acrylic powder resin between about 50 and 66.6 percent by weight of the combined weight of the first and second acrylic resins would be the second acrylic powder resin.
- the powder coating composition of the present invention also includes a crosslinker reactive with the hydroxyl functional acrylic resins.
- a crosslinker having isocyanate functionality is used.
- Isocyanate compounds useful in the compositions of this invention have at least one isocyanate group per molecule.
- Polyisocyanate crosslinkers may be prepared by modifying simple aliphatic, cycloaliphatic, araliphatic and/or aromatic diisocyanates, being constructed from at least two diisocyanates, and having a uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and/or oxadiazinetrione structure.
- Suitable diisocyanates for preparing such polyisocyanates are any desired diisocyanates of the molecular weight range 140 to 400 g/mol that are obtainable by phosgenation or by phosgene-free processes, as for example by thermal urethane cleavage, and have aliphatically, cycloaliphatically, araliphatically and/or aromatically attached isocyanate groups, such as 1,4-diisocyanatobutane, 1,6-diisocyanatohexane (HDI), 2-methyl-1,5-diisocyanatopentane, 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- and 2,4,4-trimethyl-1,6-diisocyanatohexane, 1,10-diisocyanatodecane, 1,3- and 1,4-diisocyanatocyclohexane, 1,3- and 1,4-bis(isocyanatomethyl
- the isocyanate crosslinker is a blocked isocyanate.
- Blocked isocyanate are prepared by reacting polyisocyanates with a reagent so that the polyisocyanate is stable at room temperature. Upon exposure to heat, the blocking group will dissociate to regenerate the isocyanate functionality.
- Suitable blocking groups may be selected from alcohols, caprolactam, phenols, methyl ethyl ketoxime, and active methylene compounds.
- the ratio of equivalents of isocyanate to active hydrogen can be widely varied within the practice of this invention.
- the polyisocyanate will typically be present at a level to provide about 1.0 to about 2.0, for example, about 1.0 to about 1.5, equivalents of isocyanate for each equivalent of active hydrogen from the acrylic powder resins.
- an acicular filler such as wollastonite
- the acicular filler would be present at a weight solids percent of at least 10 percent and for some embodiments, at least 15 percent, and for some embodiments at least 25 percent of the total weight solids of the coating.
- a level of acicular filler such as wollastonite, between about 10 and 35 percent by weight of the total weight solids of the final powder coating composition comprising the resins, the crosslinker and pigments.
- the coatings may also contain extender pigments, including polymeric extender pigments provided they are stable at the processing and cure temperatures of the powder coatings.
- the coating composition is substantially free of UV absorbers and hindered amine light stabilizers.
- the powder coatings of this invention can be prepared by typical means well known in the art such as by first melt blending the ingredients of the coating compositions in an extruder at a suitable temperature. The extrudate is then cooled and pulverized.
- the application of the powder coatings can be made by any means well known in the art for powder coatings such as by electrostatic spraying or by the use of a fluidized bed to any suitable substrate.
- the substrate can optionally be preheated prior to application of the powder coating composition.
- the coating is cured by heating at a temperature and for a length of time sufficient to cause the reactants to form an insoluble polymer network. Typical cure temperatures would normally range from about 100° C. to about 250° C. for a period of about 10 to about 30 minutes.
- Suitable substitutes include any substrate which is not adversely affected by the cure time and temperature and would typically include metal, glass and plastic substrates.
- the substrate can be pretreated and/or coated with one or more suitable primer coats before application of the coatings of this invention.
- Low reflectance powder coating compositions may be prepared as shown in Table 1. Unless otherwise stated, “parts” means parts-by-weight and “percent” is percent-by-weight, and equivalent weight is on a weight solids basis.
- Coating compositions as set forth in Table 1 may be prepared by blending and extruding the listed raw materials. The extrudate may then be cooled and fractured to produce a powder coating which may be applied to a suitable substrate and baked before testing for gloss and other properties.
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- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Wood Science & Technology (AREA)
- Organic Chemistry (AREA)
- Paints Or Removers (AREA)
- Polyurethanes Or Polyureas (AREA)
Abstract
A powder coating composition comprising:
-
- (a) a first acrylic powder resin having a hydroxyl value of at least about 180;
- (b) a second acrylic powder resin having a hydroxyl value between about 45 and about 80;
- (c) a crosslinker reactive with the hydroxyl functional acrylic resins; and
- (d) an acicular filler.
Description
- This invention is a continuation of U.S. application Ser. No. 13/798,329 filed on Mar. 13, 2013 and entitled “LOW REFLECTANCE POWDER COATING COMPOSITIONS”, which was made with Government support under Contract Number W912HQ-12-C-0013 awarded by the U.S. Army Corps of Engineers, HECSA. The Government has certain rights in this invention.
- Very low gloss powder coatings are desirable for a variety of uses including automotive interior parts, wheel rims, bumpers, firearms, and military applications and other articles where low reflectance is desired. A particular requirement of some military applications involves resistance to penetration by chemical warfare agents according to military specifications such as MIL-PRF-32348. For some military and commercial applications it is useful to provide a coating composition which when applied to a substrate and cured will have a 60° gloss less than 1 and an 85° gloss less than 7, for example, 3.5 or less.
- This invention therefore relates to a low gloss powder coating composition comprising:
-
- (a) a first acrylic powder resin having a hydroxyl value of at least about 180;
- (b) a second acrylic powder resin having a hydroxyl value between about 45 and 80, for example, about 60;
- (c) a crosslinker reactive with the hydroxyl functional acrylic resins; and
- (d) an acicular filler, such as wollastonite.
For certain embodiments of this invention it is useful to have the weight ratio of the first acrylic powder resin to the second acrylic powder resin be greater than about 0.5, for example about 1.0.
- One aspect of this invention involves the selection of two different hydroxyl functional acrylic powder resins having varying hydroxyl values. The production of acrylic polymers of a given hydroxyl number is well known within the art. The hydroxyl functional acrylic polymers of this invention are obtained in a customary manner, for example, by polymerizing at least one hydroxyl functional monomer, typically a hydroxyl functional (meth)acrylate such as hydroxyethyl or hydroxypropyl (meth)acrylate, along with other copolymerizable unsaturated monomers. Representative copolymerizable monomers include vinyl compounds such as styrene, methylstyrene, vinyl acetate, and the unsaturated alkyl esters of (meth)acrylic acids. Suitable alkyl (meth)acrylate monomers include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, propyl (meth)acrylate, 2-ethyl hexyl (meth)acrylate, cyclohexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, neopentyl (meth)acrylate, and 1-adamatyl methacrylate. By selecting the level of hydroxyl functional monomer which is incorporated into the acrylic powder resins, any given hydroxyl value can be selected. The polymers can be formulated to any useful glass transition temperature. For some applications it is useful to have a Tg of at least 35° C., and sometimes at least 40° C. for each of the hydroxy functional acrylic resins. For some applications it is useful to have the resin with the higher hydroxyl number have a Tg of at least 45° C. or higher to provide ever greater resistance to chemical agents.
- For this invention, a first hydroxyl functional acrylic powder resin will be produced having a hydroxyl value of at least about 180, and a second hydroxyl functional acrylic polymer resin will be produced having a hydroxyl value between about 45 and about 80. These resins are then combined with a suitable crosslinking agent reactive with hydroxyl groups, such as a blocked isocyanate or uretdione, to provide the powder coating composition. For some embodiments of this invention, the first acrylic powder resin will have a hydroxyl value between about 180 and about 300, and for some embodiments of this invention it is useful for the second acrylic powder resin to have a hydroxyl value between about 45 and 60, for some embodiments about 60. In another useful embodiment, the first acrylic powder resin will have a hydroxyl value that is at least about 150 higher than the hydroxyl value of the second acrylic powder resin, for example, at least about 150 to about 240 higher, further for example, at least about 170 to about 190 higher.
- For those applications requiring resistance to chemical agents it is often useful to provide a weight ratio of the first acrylic powder resin to the second acrylic powder resin greater than 0.5, for example, greater than 0.8, further for example about 1.0. Typically, for the combination of the first acrylic powder resin and the second acrylic powder resin, between about 33.3 weight percent and 66.6 weight percent of the total amount of hydroxy functional acrylic resin would be the first acrylic powder resin. For some applications, between about 50 and 66.6 percent by weight of the combined weight of the first and second acrylic resins would be the second acrylic powder resin.
- The powder coating composition of the present invention also includes a crosslinker reactive with the hydroxyl functional acrylic resins. In one useful embodiment a crosslinker having isocyanate functionality is used. Isocyanate compounds useful in the compositions of this invention have at least one isocyanate group per molecule. Polyisocyanate crosslinkers may be prepared by modifying simple aliphatic, cycloaliphatic, araliphatic and/or aromatic diisocyanates, being constructed from at least two diisocyanates, and having a uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and/or oxadiazinetrione structure. Suitable diisocyanates for preparing such polyisocyanates are any desired diisocyanates of the molecular weight range 140 to 400 g/mol that are obtainable by phosgenation or by phosgene-free processes, as for example by thermal urethane cleavage, and have aliphatically, cycloaliphatically, araliphatically and/or aromatically attached isocyanate groups, such as 1,4-diisocyanatobutane, 1,6-diisocyanatohexane (HDI), 2-methyl-1,5-diisocyanatopentane, 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- and 2,4,4-trimethyl-1,6-diisocyanatohexane, 1,10-diisocyanatodecane, 1,3- and 1,4-diisocyanatocyclohexane, 1,3- and 1,4-bis(isocyanatomethyl)cyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanato-methylcyclohexane (isophorone diisocyanate, IPDI), 4,4′-diisocyanatodicyclohexylmethane, 1-isocyanato-1-methyl-4(3)-isocyanatomethylcyclohexane, bis(isocyanatomethyl)norbornane, 1,3- and 1,4-bis(2-isocyanatoprop-2-yl)benzene (TMXDI), 2,4- and 2,6-diisocyanatotoluene (TDI), 2,4′- and 4,4′-diisocyanatodiphenylmethane (MDI), 1,5-diisocyanatonaphthalene or any desired mixtures of such diisocyanates. Useful polyisocyanates or polyisocyanate mixtures may contain exclusively aliphatically and/or cycloaliphatically attached isocyante groups.
- In one useful embodiment, the isocyanate crosslinker is a blocked isocyanate. Blocked isocyanate are prepared by reacting polyisocyanates with a reagent so that the polyisocyanate is stable at room temperature. Upon exposure to heat, the blocking group will dissociate to regenerate the isocyanate functionality. Suitable blocking groups may be selected from alcohols, caprolactam, phenols, methyl ethyl ketoxime, and active methylene compounds.
- The ratio of equivalents of isocyanate to active hydrogen can be widely varied within the practice of this invention. The polyisocyanate will typically be present at a level to provide about 1.0 to about 2.0, for example, about 1.0 to about 1.5, equivalents of isocyanate for each equivalent of active hydrogen from the acrylic powder resins.
- Additionally, it has been found that the use of an acicular filler, such as wollastonite, as a flattening pigment is useful in meeting the very low gloss and chemical resistance requirements of these coatings. Typically, the acicular filler, such as wollastonite, would be present at a weight solids percent of at least 10 percent and for some embodiments, at least 15 percent, and for some embodiments at least 25 percent of the total weight solids of the coating. For some applications it is useful to use a level of acicular filler, such as wollastonite, between about 10 and 35 percent by weight of the total weight solids of the final powder coating composition comprising the resins, the crosslinker and pigments.
- Additional pigments such as titanium dioxide, metallic pigments, iron oxides, carbon black, organic pigments etc. can also be included. The coatings may also contain extender pigments, including polymeric extender pigments provided they are stable at the processing and cure temperatures of the powder coatings.
- Additives such as flow agents, degassing agents, antistatic agents, plasticizers, light stabilizers, light absorbers, catalysts etc. can also be added. In one useful embodiment of the invention, the coating composition is substantially free of UV absorbers and hindered amine light stabilizers.
- The powder coatings of this invention can be prepared by typical means well known in the art such as by first melt blending the ingredients of the coating compositions in an extruder at a suitable temperature. The extrudate is then cooled and pulverized.
- The application of the powder coatings can be made by any means well known in the art for powder coatings such as by electrostatic spraying or by the use of a fluidized bed to any suitable substrate. If desired, the substrate can optionally be preheated prior to application of the powder coating composition. Once the coating composition has been applied to the substrate, the coating is cured by heating at a temperature and for a length of time sufficient to cause the reactants to form an insoluble polymer network. Typical cure temperatures would normally range from about 100° C. to about 250° C. for a period of about 10 to about 30 minutes. Suitable substitutes include any substrate which is not adversely affected by the cure time and temperature and would typically include metal, glass and plastic substrates. If desired, the substrate can be pretreated and/or coated with one or more suitable primer coats before application of the coatings of this invention.
- The following examples illustrate embodiments and practices of advantage to a more complete understanding of the invention. Low reflectance powder coating compositions may be prepared as shown in Table 1. Unless otherwise stated, “parts” means parts-by-weight and “percent” is percent-by-weight, and equivalent weight is on a weight solids basis.
- Coating compositions as set forth in Table 1 may be prepared by blending and extruding the listed raw materials. The extrudate may then be cooled and fractured to produce a powder coating which may be applied to a suitable substrate and baked before testing for gloss and other properties.
-
RAW MATERIAL EX. #1 EX. #2 Hydroxy 150 184 functional acrylic1 Hydroxy 150 184 functional acrylic2 Blocked 349 281 isocyanate3 Flow agent4 10 10 Benzoin 5 5 Wollastonite 210 210 Surfactant5 4 4 Hindered 20 Amine Light Stabilizer6 UV Absorber7 40 Iron oxide 47.5 47.5 black pigment Carbon black 2.5 2.5 powder Gloss 60/85 0.4/2.4 0.5/3.2 1Acrylic powder resin having a hydroxyl number of 60. 2Acrylic powder resin having a hydroxyl number of 250. 3Vestagon ™B 1530 e-caprolactam blocked IPDI commercially available from Degussa. 4Resiflow P-67 flow agent commercially available from Estron Chemical. 5SURFYNOL ® 104S surfactant commercially available from Air Products. 6TINUVIN ® 144 HALS commercially available from BASF 7TINUVIN ® 928 commercially available from BASF - While this invention has been described by a specific number of embodiments, other variations and modifications may be made without departing from the spirit and scope of the invention as set forth in the appended claims.
Claims (16)
1. A powder coating composition comprising:
(a) a first hydroxyl functional acrylic powder resin having a hydroxyl value of at least about 180;
(b) a second hydroxyl functional acrylic powder resin having a hydroxyl value between about 45 and about 80;
(c) a crosslinker reactive with the first and second hydroxyl functional acrylic resins; and
(d) an acicular filler;
and wherein the weight ratio of the first acrylic powder resin to the second acrylic powder resin is greater than 0.5.
2. The powder coating composition of claim 1 wherein the coating composition when applied to a substrate and cured will have a 60° gloss less than 1 and an 85° gloss 3.5 or less.
3. The powder coating composition of claim 1 wherein the first acrylic powder resin has a hydroxyl value between 180 and 250.
4. The powder coating composition of claim 1 wherein the second acrylic powder resin has a hydroxyl value between 45 and 60.
5. The powder coating composition of claim 1 wherein the second acrylic powder resin has a hydroxyl value of about 60.
6. The powder coating composition of claim 1 wherein the acicular filler is wollastonite.
7. The powder coating composition of claim 1 wherein the wollastonite is present at a level of at least 10% by weight solids of the coating composition.
8. The powder coating composition of claim 1 wherein the wollastonite is present at a level of at least 15% by weight solids of the coating composition.
9. The powder coating composition of claim 1 wherein the wollastonite is present at a level of at least 25% by weight solids of the coating composition.
10. The powder coating composition of claim 1 wherein the first acrylic powder resin and the second acrylic powder resin each have a Tg of at least 35° C.
11. The powder coating composition of claim 1 wherein the first acrylic powder resin has a Tg of at least 45° C.
12. The powder coating composition of claim 1 wherein the first acrylic polymer is present at a level to provide between about 33.3 weight percent and 85.1 weight percent of the total combined weight of the first acrylic polymer and the second acrylic polymer.
13. The powder coating composition of claim 1 wherein the first acrylic polymer is present at a level to provide between about 33.3 weight percent and 66.6 weight percent of the total combined weight of the first acrylic polymer and the second acrylic polymer.
14. The powder coating composition of claim 1 wherein the crosslinker is an isocyanate compound.
15. The powder coating composition of claim 14 wherein the isocyanate compound is present at a level to provide about 1.0 to about 1.5 equivalents of isocyanate functionality for each equivalent of active hydrogen of the first and second hydroxyl functional acrylic resins.
16. A process of coating a substrate which process comprises:
(i) applying a powder coating composition to a substrate; and
(ii) heating the coated substrate at a temperature and for a length of time sufficient to cause the composition to form an insoluble polymer network;
and wherein the powder coating composition comprises:
(a) a first hydroxyl functional acrylic powder resin having a hydroxyl value of at least about 180;
(b) a second hydroxyl functional acrylic powder resin having a hydroxyl value between about 45 and about 80;
(c) a crosslinker reactive with the hydroxyl functional acrylic resins; and
(d) wollastonite;
and wherein the weight ratio of the first acrylic powder resin to the second acrylic powder resin is greater than 0.5.
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| Application Number | Priority Date | Filing Date | Title |
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| US16/556,574 US20200140696A1 (en) | 2013-03-13 | 2019-08-30 | Low reflectance powder coating compositions |
| US17/477,072 US20220204779A1 (en) | 2013-03-13 | 2021-09-16 | Low reflectance powder coated article |
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| US13/798,329 US10428225B1 (en) | 2013-03-13 | 2013-03-13 | Low reflectance powder coating composition |
| US16/556,574 US20200140696A1 (en) | 2013-03-13 | 2019-08-30 | Low reflectance powder coating compositions |
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| US13/798,329 Continuation US10428225B1 (en) | 2013-03-13 | 2013-03-13 | Low reflectance powder coating composition |
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| EP3368620B1 (en) | 2015-10-28 | 2022-03-23 | Swimc LLC | Polyurethane coating composition |
| CN115746638B (en) * | 2022-09-28 | 2023-08-18 | 欧利生东邦涂料(东莞)有限公司 | Low-reflectivity coating and preparation method and application thereof |
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| US5239018A (en) * | 1989-09-06 | 1993-08-24 | Exxon Chemical Patents Inc. | Liquid polymer and polyol compositions, and process for preparing phenol-functional polymer |
| US6114489A (en) * | 1997-03-27 | 2000-09-05 | Herberts Gmbh | Reactive hyperbranched polymers for powder coatings |
| ATE301168T1 (en) * | 2000-05-23 | 2005-08-15 | Akzo Nobel Coatings Int Bv | PRODUCTION OF A DECORATED SUBSTRATE USING A THERMALLY CROSS-LINKABLE COATING COMPOSITION |
| US6737467B1 (en) * | 2000-11-21 | 2004-05-18 | E. I. Du Pont De Nemours And Company | Low gloss powder coatings |
| US7122585B2 (en) * | 2003-05-13 | 2006-10-17 | Rohm And Haas Company | Coating powders, methods of manufacture thereof, and articles formed therefrom |
| EP1519389A1 (en) * | 2003-09-18 | 2005-03-30 | Rohm And Haas Company | Electrically insulative powder coatings and compositions and methods for making them |
| EP1980582A1 (en) * | 2007-04-13 | 2008-10-15 | Cytec Italy, S.R.L. | Branched polyester for powder coatings |
| US20110269908A1 (en) * | 2008-11-07 | 2011-11-03 | Jansen Johan F G A | One component heat-curable powder coating composition |
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