CN116987438B - Improved two-component polyurethane coating - Google Patents
Improved two-component polyurethane coating Download PDFInfo
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- CN116987438B CN116987438B CN202311054911.8A CN202311054911A CN116987438B CN 116987438 B CN116987438 B CN 116987438B CN 202311054911 A CN202311054911 A CN 202311054911A CN 116987438 B CN116987438 B CN 116987438B
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- 239000011527 polyurethane coating Substances 0.000 title claims abstract description 33
- 125000002887 hydroxy group Chemical group [H]O* 0.000 claims abstract description 132
- 238000000576 coating method Methods 0.000 claims abstract description 62
- 239000011248 coating agent Substances 0.000 claims abstract description 58
- 229920005989 resin Polymers 0.000 claims abstract description 50
- 239000011347 resin Substances 0.000 claims abstract description 50
- 229920000728 polyester Polymers 0.000 claims abstract description 48
- 239000003085 diluting agent Substances 0.000 claims abstract description 43
- 239000002253 acid Substances 0.000 claims abstract description 31
- 239000004814 polyurethane Substances 0.000 claims abstract description 30
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 27
- 239000003054 catalyst Substances 0.000 claims abstract description 24
- 238000002156 mixing Methods 0.000 claims abstract description 18
- 238000000034 method Methods 0.000 claims abstract description 17
- 238000001816 cooling Methods 0.000 claims abstract description 16
- 229920002635 polyurethane Polymers 0.000 claims abstract description 14
- 150000005846 sugar alcohols Polymers 0.000 claims abstract description 12
- 238000003756 stirring Methods 0.000 claims abstract description 11
- 150000008064 anhydrides Chemical class 0.000 claims abstract description 10
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 claims abstract description 8
- 239000012752 auxiliary agent Substances 0.000 claims abstract description 4
- BRLQWZUYTZBJKN-UHFFFAOYSA-N Epichlorohydrin Chemical compound ClCC1CO1 BRLQWZUYTZBJKN-UHFFFAOYSA-N 0.000 claims description 16
- HWCKGOZZJDHMNC-UHFFFAOYSA-M tetraethylammonium bromide Chemical compound [Br-].CC[N+](CC)(CC)CC HWCKGOZZJDHMNC-UHFFFAOYSA-M 0.000 claims description 11
- QNYBOILAKBSWFG-UHFFFAOYSA-N 2-(phenylmethoxymethyl)oxirane Chemical compound C1OC1COCC1=CC=CC=C1 QNYBOILAKBSWFG-UHFFFAOYSA-N 0.000 claims description 8
- CTKINSOISVBQLD-UHFFFAOYSA-N Glycidol Chemical compound OCC1CO1 CTKINSOISVBQLD-UHFFFAOYSA-N 0.000 claims description 8
- RIOQSEWOXXDEQQ-UHFFFAOYSA-N triphenylphosphine Chemical compound C1=CC=CC=C1P(C=1C=CC=CC=1)C1=CC=CC=C1 RIOQSEWOXXDEQQ-UHFFFAOYSA-N 0.000 claims description 8
- YSUQLAYJZDEMOT-UHFFFAOYSA-N 2-(butoxymethyl)oxirane Chemical compound CCCCOCC1CO1 YSUQLAYJZDEMOT-UHFFFAOYSA-N 0.000 claims description 6
- HRWYHCYGVIJOEC-UHFFFAOYSA-N 2-(octoxymethyl)oxirane Chemical compound CCCCCCCCOCC1CO1 HRWYHCYGVIJOEC-UHFFFAOYSA-N 0.000 claims description 6
- LGRFSURHDFAFJT-UHFFFAOYSA-N Phthalic anhydride Natural products C1=CC=C2C(=O)OC(=O)C2=C1 LGRFSURHDFAFJT-UHFFFAOYSA-N 0.000 claims description 6
- JHIWVOJDXOSYLW-UHFFFAOYSA-N butyl 2,2-difluorocyclopropane-1-carboxylate Chemical compound CCCCOC(=O)C1CC1(F)F JHIWVOJDXOSYLW-UHFFFAOYSA-N 0.000 claims description 6
- WMYINDVYGQKYMI-UHFFFAOYSA-N 2-[2,2-bis(hydroxymethyl)butoxymethyl]-2-ethylpropane-1,3-diol Chemical compound CCC(CO)(CO)COCC(CC)(CO)CO WMYINDVYGQKYMI-UHFFFAOYSA-N 0.000 claims description 5
- 150000001875 compounds Chemical class 0.000 claims description 5
- JRMUNVKIHCOMHV-UHFFFAOYSA-M tetrabutylammonium bromide Chemical compound [Br-].CCCC[N+](CCCC)(CCCC)CCCC JRMUNVKIHCOMHV-UHFFFAOYSA-M 0.000 claims description 5
- TXBCBTDQIULDIA-UHFFFAOYSA-N 2-[[3-hydroxy-2,2-bis(hydroxymethyl)propoxy]methyl]-2-(hydroxymethyl)propane-1,3-diol Chemical compound OCC(CO)(CO)COCC(CO)(CO)CO TXBCBTDQIULDIA-UHFFFAOYSA-N 0.000 claims description 4
- MUTGBJKUEZFXGO-OLQVQODUSA-N (3as,7ar)-3a,4,5,6,7,7a-hexahydro-2-benzofuran-1,3-dione Chemical compound C1CCC[C@@H]2C(=O)OC(=O)[C@@H]21 MUTGBJKUEZFXGO-OLQVQODUSA-N 0.000 claims description 3
- JPSKCQCQZUGWNM-UHFFFAOYSA-N 2,7-Oxepanedione Chemical compound O=C1CCCCC(=O)O1 JPSKCQCQZUGWNM-UHFFFAOYSA-N 0.000 claims description 3
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 claims description 3
- VANNPISTIUFMLH-UHFFFAOYSA-N glutaric anhydride Chemical compound O=C1CCCC(=O)O1 VANNPISTIUFMLH-UHFFFAOYSA-N 0.000 claims description 3
- VYKXQOYUCMREIS-UHFFFAOYSA-N methylhexahydrophthalic anhydride Chemical compound C1CCCC2C(=O)OC(=O)C21C VYKXQOYUCMREIS-UHFFFAOYSA-N 0.000 claims description 3
- WXZMFSXDPGVJKK-UHFFFAOYSA-N pentaerythritol Chemical compound OCC(CO)(CO)CO WXZMFSXDPGVJKK-UHFFFAOYSA-N 0.000 claims description 3
- 235000002906 tartaric acid Nutrition 0.000 claims description 3
- 239000011975 tartaric acid Substances 0.000 claims description 3
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 claims description 2
- INJAHHABQHQOMY-UHFFFAOYSA-N 2-(dihydroxymethyl)butanoic acid Chemical compound CCC(C(O)O)C(O)=O INJAHHABQHQOMY-UHFFFAOYSA-N 0.000 claims 1
- 239000007787 solid Substances 0.000 abstract description 32
- 238000010276 construction Methods 0.000 abstract description 31
- 230000004913 activation Effects 0.000 abstract description 19
- 229920001225 polyester resin Polymers 0.000 abstract description 17
- 239000004645 polyester resin Substances 0.000 abstract description 16
- 239000000126 substance Substances 0.000 abstract description 14
- 238000002360 preparation method Methods 0.000 description 43
- 239000003973 paint Substances 0.000 description 28
- 238000006243 chemical reaction Methods 0.000 description 23
- 239000000203 mixture Substances 0.000 description 16
- 239000012855 volatile organic compound Substances 0.000 description 16
- 238000010521 absorption reaction Methods 0.000 description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 11
- 238000007599 discharging Methods 0.000 description 10
- 239000000463 material Substances 0.000 description 10
- 239000002904 solvent Substances 0.000 description 10
- 239000005056 polyisocyanate Substances 0.000 description 9
- 229920001228 polyisocyanate Polymers 0.000 description 9
- 238000005507 spraying Methods 0.000 description 9
- LAVARTIQQDZFNT-UHFFFAOYSA-N 1-(1-methoxypropan-2-yloxy)propan-2-yl acetate Chemical compound COCC(C)OCC(C)OC(C)=O LAVARTIQQDZFNT-UHFFFAOYSA-N 0.000 description 8
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 8
- 239000002518 antifoaming agent Substances 0.000 description 8
- 238000009472 formulation Methods 0.000 description 8
- 239000011521 glass Substances 0.000 description 8
- 230000005484 gravity Effects 0.000 description 8
- 239000001257 hydrogen Substances 0.000 description 8
- 229910052739 hydrogen Inorganic materials 0.000 description 8
- 239000007788 liquid Substances 0.000 description 8
- 239000011435 rock Substances 0.000 description 8
- 239000007921 spray Substances 0.000 description 8
- 239000005028 tinplate Substances 0.000 description 8
- 239000002023 wood Substances 0.000 description 8
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 5
- 238000007142 ring opening reaction Methods 0.000 description 5
- PTBDIHRZYDMNKB-UHFFFAOYSA-N 2,2-Bis(hydroxymethyl)propionic acid Chemical compound OCC(C)(CO)C(O)=O PTBDIHRZYDMNKB-UHFFFAOYSA-N 0.000 description 4
- JVYDLYGCSIHCMR-UHFFFAOYSA-N 2,2-bis(hydroxymethyl)butanoic acid Chemical compound CCC(CO)(CO)C(O)=O JVYDLYGCSIHCMR-UHFFFAOYSA-N 0.000 description 4
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 description 4
- 239000008096 xylene Substances 0.000 description 4
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 3
- 125000003700 epoxy group Chemical group 0.000 description 3
- XQSBLCWFZRTIEO-UHFFFAOYSA-N hexadecan-1-amine;hydrobromide Chemical compound [Br-].CCCCCCCCCCCCCCCC[NH3+] XQSBLCWFZRTIEO-UHFFFAOYSA-N 0.000 description 3
- 238000002329 infrared spectrum Methods 0.000 description 3
- 238000006068 polycondensation reaction Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- -1 small molecule hydroxyl polyol Chemical class 0.000 description 3
- PAPBSGBWRJIAAV-UHFFFAOYSA-N ε-Caprolactone Chemical compound O=C1CCCCCO1 PAPBSGBWRJIAAV-UHFFFAOYSA-N 0.000 description 3
- FALRKNHUBBKYCC-UHFFFAOYSA-N 2-(chloromethyl)pyridine-3-carbonitrile Chemical compound ClCC1=NC=CC=C1C#N FALRKNHUBBKYCC-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 239000004721 Polyphenylene oxide Substances 0.000 description 2
- ZJCCRDAZUWHFQH-UHFFFAOYSA-N Trimethylolpropane Chemical compound CCC(CO)(CO)CO ZJCCRDAZUWHFQH-UHFFFAOYSA-N 0.000 description 2
- 150000001555 benzenes Chemical class 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- GYZLOYUZLJXAJU-UHFFFAOYSA-N diglycidyl ether Chemical compound C1OC1COCC1CO1 GYZLOYUZLJXAJU-UHFFFAOYSA-N 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 235000011187 glycerol Nutrition 0.000 description 2
- 235000014655 lactic acid Nutrition 0.000 description 2
- 239000004310 lactic acid Substances 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 150000002917 oxazolidines Chemical class 0.000 description 2
- 229920000570 polyether Polymers 0.000 description 2
- 229920005862 polyol Polymers 0.000 description 2
- 150000007519 polyprotic acids Polymers 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 229940014800 succinic anhydride Drugs 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 241000110847 Kochia Species 0.000 description 1
- WYNCHZVNFNFDNH-UHFFFAOYSA-N Oxazolidine Chemical compound C1COCN1 WYNCHZVNFNFDNH-UHFFFAOYSA-N 0.000 description 1
- 239000004972 Polyurethane varnish Substances 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 229920000180 alkyd Polymers 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000008199 coating composition Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 239000013530 defoamer Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 235000014113 dietary fatty acids Nutrition 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 125000004185 ester group Chemical group 0.000 description 1
- 238000005886 esterification reaction Methods 0.000 description 1
- 229930195729 fatty acid Natural products 0.000 description 1
- 239000000194 fatty acid Substances 0.000 description 1
- 150000004665 fatty acids Chemical class 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000003999 initiator Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 125000001434 methanylylidene group Chemical group [H]C#[*] 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
- 238000000655 nuclear magnetic resonance spectrum Methods 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 150000003077 polyols Chemical class 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000000425 proton nuclear magnetic resonance spectrum Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 239000000080 wetting agent Substances 0.000 description 1
- 238000004383 yellowing Methods 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
- C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
- C09D175/04—Polyurethanes
- C09D175/06—Polyurethanes from polyesters
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/40—High-molecular-weight compounds
- C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
- C08G18/4291—Polycondensates having carboxylic or carbonic ester groups in the main chain prepared from polyester forming components containing monoepoxy compounds
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Wood Science & Technology (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Paints Or Removers (AREA)
- Polyurethanes Or Polyureas (AREA)
Abstract
The invention relates to an improved two-component polyurethane coating, which comprises a hydroxyl component and a polyurethane curing agent component, wherein the hydroxyl component consists of hydroxyl resin and a coating auxiliary agent, and is characterized in that the hydroxyl resin is prepared by mixing star-shaped hydroxyl polyester and a reactive diluent; wherein, the star hydroxyl polyester resin is prepared by the following method: mixing polyalcohol, anhydride and monoepoxide, adding a catalyst, stirring uniformly, reacting at 90-110 ℃ until the acid value reaches 2-10mgKOH/g, and cooling to room temperature to obtain the star-shaped hydroxyl polyester resin; the reactive diluent is prepared by the following method: and mixing hydroxycarboxylic acid with a monoepoxide, adding the catalyst, reacting at 90-120 ℃ until the acid value reaches 2-5mgKOH/g, and cooling to room temperature to obtain the active diluent. The coating has the advantages of long activation period, low construction viscosity, high construction solid content and good chemical resistance of the coating.
Description
Technical Field
The present invention relates to coating compositions, in particular to polyurethane-based two-component coatings, which are suitable for use in automotive coatings.
Background
The solvent-based two-component polyurethane coating (2K-PU) is one of the coating varieties with the most excellent comprehensive performance, the development of the high-solid-content two-component polyurethane coating, the reduction of the Volatile Organic Compound (VOC) content of the existing 2K-PU coating product, is a hot spot in the research of the coating industry, and the technical key is the development of the hydroxyl resin with low viscosity and high solid content. One of the important properties of the high solid content 2K-PU coating is the activation period of the coating, also called the construction time limit, which is counted from the time when the hydroxyl resin is mixed with the curing agent, the viscosity of the coating increases along with the extension of the storage time, and the time is called the activation period of the two-component coating when the coating performance is reduced, the longer the activation period is, the longer the construction time of the 2K-PU can be, the more convenient the construction is, and the coating is not wasted due to the slow construction progress. The high-solid content 2K-PU coating prepared by linear hydroxyl oligomer with the molecular weight of about 1000 at present has the defects of short activation period of 2 hours, low drying speed of a coating film and poor chemical resistance, and limits the use of the coating. The traditional high molecular weight hydroxyl resin is adopted, and the double oxazolidine reactive diluent is added, so that the high performance and low VOC content can be achieved, the existing double oxazolidines are high in price and large in addition amount, and the cost of the double oxazolidines is often more than 50% of the total cost of the 2K-PU coating; the existing small molecule hydroxyl polyol cannot be used as a reactive diluent.
On the other hand, the traditional solvent type 2K-PU coating is prepared by polycondensation reaction of polyhydric alcohol and polybasic acid (or anhydride) under high temperature (200-240 ℃), the preparation process has high reaction temperature, the used xylene water-carrying agent is not environment-friendly, the molecular structure of the product resin is mostly linear structure, and the defects of high molecular weight, high viscosity and low solid content, namely low viscosity and high solid content are difficult to be compatible, are overcome. Patent applications with publication numbers CN102911349a and CN104262599a disclose that caprolactone, fatty acid and monoglycidyl ether are utilized to modify hyperbranched hydroxyl polyester, and benzene series such as xylene is used as a water-carrying agent to promote polycondensation reaction, so that xylene remains in the product, and the xylene does not meet the increasingly severe environmental protection requirements. The patent application with publication number of CN 106279659A discloses a star-shaped hydroxyl polyester with polyalcohol as a core, a preparation method and application thereof, which comprises the steps of firstly taking micromolecular polyalcohol as a core molecule, firstly reacting with caprolactone at 80-140 ℃ for 6-10 hours to obtain matrix star-shaped polyester, and then reacting with monoglycidyl ether at 90-150 ℃ to obtain the star-shaped hydroxyl polyester.
Disclosure of Invention
The technical problem to be solved by the invention is to provide an improved two-component polyurethane coating, which has the advantages of long activation period, low construction viscosity, high construction solid content and good chemical resistance of a coating film.
The technical problem solved by the invention is as follows:
the improved two-component polyurethane coating comprises a hydroxyl component and a polyurethane curing agent component, wherein the hydroxyl component consists of hydroxyl resin and a coating auxiliary agent, and is characterized in that the hydroxyl resin is prepared by mixing star-shaped hydroxyl polyester and a reactive diluent according to the mass ratio of star-shaped hydroxyl polyester to reactive diluent = 0.25-4:1; wherein,
the star hydroxyl polyester resin is prepared by the following method:
mixing polyalcohol, anhydride with the molar quantity of 1-6 times of that of the polyalcohol and monoepoxide with the molar quantity of the anhydride, adding a catalyst accounting for 0.05-0.2% of the mass of the monoepoxide, uniformly stirring, reacting at 90-110 ℃ until the acid value reaches 2-10mgKOH/g, and cooling to room temperature to obtain the star-shaped hydroxyl polyester resin;
the reactive diluent is prepared by the following method: mixing hydroxycarboxylic acid and the monoepoxide of the same molar weight of hydroxycarboxylic acid, adding the catalyst according to the mass of 0.05-0.2% of the monoepoxide, reacting at 90-120 ℃ until the acid value reaches 2-5mgKOH/g, and cooling to room temperature to obtain the active diluent;
the anhydride is one of phthalic anhydride, hexahydrophthalic anhydride, methyl hexahydrophthalic anhydride, succinic anhydride, adipic anhydride and glutaric anhydride;
the polyalcohol is one of glycerol, trimethylolpropane, pentaerythritol, ditrimethylolpropane, dipentaerythritol and trifunctional polyether N303;
the monoepoxide compound is one of epichlorohydrin, glycidol, butyl glycidyl ether, benzyl glycidyl ether and octyl glycidyl ether;
the hydroxy carboxylic acid is one of dimethylolpropionic acid, dimethylolbutyric acid, tartaric acid and lactic acid;
the catalyst is one of tetraethylammonium bromide, tetrabutylammonium bromide, hexadecyl ammonium bromide and triphenylphosphine.
In the technical scheme, the coating auxiliary agent is common pigment, defoamer, wetting agent and flatting agent.
In the above technical solution, the polyurethane curing agent (i.e. polyisocyanate curing agent) is Desmodur N3600, desmodur N3900 or Desmodur N75 manufactured by kesichuang, or may be HT600 or HT100 manufactured by Lefutaiwanhua.
Compared with the prior art, the invention has the following beneficial effects:
(1) The activation period is more than 4 hours and up to 24 hours. The activation period is determined by the hydroxyl activity of the hydroxyl resin, wherein the reactivity of the primary hydroxyl and NCO groups is greater than that of the secondary hydroxyl, and if the content of the secondary hydroxyl in the hydroxyl resin is increased, the activation period of the 2K-PU coating can be prolonged; therefore, the equimolar hydroxycarboxylic acid and the monoepoxide react to prepare the reactive diluent, at least contains 1 secondary hydroxyl, and the activation period of the 2K-PU coating can be conveniently adjusted to more than 4 hours through the addition amount of the reactive diluent.
(2) The paint has high construction solid content and VOC content lower than 300g/L. The construction viscosity of the high-solid-content hydroxyl resin can be conveniently reduced by adding a self-made secondary hydroxyl-containing reactive diluent; on the other hand, the viscosity of the coating is related to the magnitude of hydrogen bonding between hydroxyl groups, and the hydrogen bonding between primary hydroxyl groups is generally greater than the hydrogen bonding between secondary hydroxyl groups and between primary and secondary hydroxyl groups. This patent adopts polyol and anhydride reaction to react with monoepoxy compound again, prepares star hydroxyl resin, consumes a primary hydroxyl and generates a secondary hydroxyl simultaneously, under the unchangeable circumstances of hydroxyl functionality, reduces resin viscosity from the resin structure, still because the formation of secondary hydroxyl reduces the hydrogen bond effect between the hydroxyl, also further reduces resin and coating viscosity.
(3) The 2K-PU coating film has excellent chemical resistance. The method adopts the polyhydric alcohol with the hydroxyl functionality more than 3 as the initiator, and the preparation method of the invention can not reduce the hydroxyl functionality, so that the coating film can be ensured to have enough crosslinking density and chemical resistance;
(4) The preparation process of the reactive diluent and the star-shaped hydroxyl resin is simple, energy-saving and environment-friendly. Compared with the traditional method for preparing hydroxyl polyester or alkyd resin by polycondensation reaction of polybasic acid and polyhydric alcohol at high temperature (200-240 ℃), the method is simpler and more convenient in process by adopting a one-step feeding method through ring-opening reaction of anhydride and hydroxyl and ring-opening reaction of carboxyl and epoxy, wherein water is not generated by the reaction at the reaction temperature lower than 120 ℃. The 2K-PU coating prepared from the product resin has high construction solid content, low VOC content, long activation period and excellent chemical resistance, and is an environment-friendly product.
Drawings
FIG. 1 is a schematic diagram of a star polyester synthesized in example 1 below 1 H NMR spectrum.
Fig. 2 is an infrared spectrum of the star resin prepared in the following examples 1 and 2.
Detailed Description
For a better understanding of the present invention, the present invention will be further described with reference to the following examples.
The reference Desmophen 670BA in the following examples is a slightly branched hydroxyl polyester resin produced by Bayer Kochia company, is mainly used for a two-component polyurethane system, and the coating film has excellent weather resistance stability and excellent low-temperature flexibility, and is a polyester resin with a relatively large market share at present.
In the following examples, the properties of the star hydroxyl polyester resin and the two-component polyurethane coating were measured by the following methods: resin viscosity was measured according to GB/T21059-2007 using an NDJ model one rotational viscometer; the acid value of the resin was determined according to GB/T6743-2008; the drying time of the coating film was determined according to GB/T1728-1989; film hardness was determined according to GB/T6739-2006; film adhesion was determined according to GB/T9286-1998; the impact resistance of the coating film was determined according to GB/T1732-1993; 60 is used according to GB/T9754-2007. Measuring the gloss of the coating film by a corner WGG60-E4 type gloss meter; according to GB/T5209-1985, the water resistance of the coating film is measured by adopting a room temperature soaking method; other properties of the coating were measured according to GB/T23985-2009 et al.
Example 1
1. Preparation of hydroxy resins
Preparation of Star hydroxyl polyester: 250.33g (1 mol) of ditrimethylolpropane, 296.24g (2 mol) of phthalic anhydride and 185g (2 mol) of epichlorohydrin are added into a reaction kettle, 0.37g (0.2% of the mass of epichlorohydrin) of tetraethylammonium bromide serving as a catalyst is added, the temperature is raised and kept at 90-110 ℃ for reaction for 4 hours until the acid value is below 10mgKOH/g, and then the star-shaped hydroxyl polyester resin is obtained after cooling and discharging.
Preparation of reactive diluent: 134.13g (1 mol) of dimethylolpropionic acid, 92.5g (1 mol) of epichlorohydrin and 0.09g (0.1% of the mass of epichlorohydrin) of tetraethylammonium bromide serving as a catalyst are added into a reactor to react for 4 hours at 90-110 ℃ until the acid value reaches below 5mgKOH/g, and then the reactive diluent is obtained after cooling and discharging.
Preparation of high solids content hydroxyl resins: mixing the prepared star-shaped hydroxyl polyester and an active diluent according to the mass ratio of 4:1, and adding a proper amount of dipropylene glycol methyl ether acetate to adjust the solid content of the hydroxyl polyester to 80%, wherein the performance is as follows: water white transparent liquid with viscosity (25 ℃) of 2000mPa.s; an acid value of 3.6mgKOH/g; OH% = 8.5%.
2. Preparation of improved two-component polyurethane coating
The formulation of the improved two-component polyurethane coating of this example is shown in Table 1 below:
TABLE 1
Sequentially adding hydroxyl polyester, a solvent, a leveling agent, a defoaming agent and a polyurethane (polyisocyanate) curing agent into a material dispersing cylinder according to the formula of the table 1, stirring for 5-10 min at a rotating speed of 1000-500 r/min by using a GFJ-0.4 high-speed dispersing machine to obtain a uniformly mixed bi-component polyurethane coating, standing, and preparing a coating film on a glass plate by using a 50 mu m wet film coater after bubbles escape so as to test the hardness of the coating film; the gloss, adhesion, flexibility, impact resistance, chemical resistance and the like of the cured paint film were tested after 7 days of curing at room temperature by spraying on a wood board and a tin plate with a W-77-3G gravity spray gun (nozzle diameter 2.5mm, japanese ANEST IWATA Co.). The VOC content of the paint construction was tested according to GB/T23985-2009. The paint pot life was tested using NK-2 type rock Tian Niandu cup (Japanese ANEST IWATA Co.). The film properties are shown in Table 2 below:
TABLE 2
The reaction equation and the product structure of the star-shaped hydroxyl resin are shown in the following formula (I)In the formula, 1 mole of hydroxyl groups of ditrimethylolpropane and 2 moles of phthalic anhydride are subjected to ring-opening reaction, and the generated carboxyl groups and epoxy groups of epichlorohydrin are subjected to ring-opening reaction to generate star-shaped hydroxyl resin containing secondary hydroxyl groups. FIG. 1 is a nuclear magnetic resonance spectrum of a star-shaped hydroxyl resin, each peak belonging to the following: a peak having a relative integrated area of about 0.8ppm and 6 is attributed to methyl hydrogen No. 1; the peak with the relative integral area of 4 between 1.6 and 1.2ppm belongs to No. 2 methylene hydrogen; peaks between 3.5 and 3.0ppm with a relative integrated area of 8 are considered to be No. 3, no. 4 and No. 5 methylenehydrogens; the peak having a relative integrated area of 4 between 3.8 and 3.6ppm was considered to be No. 12 methylenehydrogen linked to chlorine; peaks between 4.1 and 3.9ppm with a relative integrated area of 2 are considered to be 11 # methine hydrogen attached to a secondary hydroxyl group; peaks between 4.4 and 4.1ppm with a relative integrated area of 8 are considered to be the 7 and 10 methylenehydrogens attached to the ester group; three groups of small peaks between 4.4 and 5.8ppm with a relative integration area of 4 are considered to be the 6 and 13 primary secondary hydroxyl groups of the star hydroxyl polyester; peaks between 8.0 and 7.4ppm with respect to the integrated area of 8 are considered to be hydrogen numbers 8 and 9 on the benzene ring structure. The above description we have obtained the structure of a star-shaped hydroxyl resin. FIG. 2 is an infrared spectrum of a star-shaped hydroxyl resin, of which 3470cm -1 The strong and broad absorption peak occurring nearby is considered to be a characteristic absorption peak of hydroxyl groups (-OH) in the star-shaped hydroxyl resin. 2946 and 2865cm -1 The absorption peaks at the positions are methyl and methylene (-CH) 3 、-CH 2 (-) expansion vibration absorption peak, 1728cm -1 The sharp strong absorption peak occurring nearby is considered as the telescopic vibration absorption peak of the ester carbonyl (-C (O) O-). 1455cm -1 The absorption peak at this point is-CH 3 Bending vibration absorption peaks, 1180 and 1035cm -1 The absorption peak at the position is a-C-O-telescopic vibration absorption peak; 755cm -1 The absorption peak at this point is assigned to the characteristic absorption peak of-C-Cl. No raw material ECH is located at 905cm in the infrared spectrogram -1 The characteristic absorption peak of epoxy group at the position shows that the epoxy group and carboxyl group have ring-opening reaction and secondary hydroxyl group is generated. The synthesized series of star hydroxyl polyesters are shown to have similar molecular skeleton structures.
Table 2 shows that the 2K-PU varnish prepared by using N3390 as the curing agent has the construction activation period of more than 24 hours, and the paint film has the properties of high glossiness, transparency, hardness, adhesive force, flexibility and the like. Has obvious advantages in the aspects of impact resistance, yellowing resistance and weather resistance. Comparative example data shown in the table are the properties of 2K-PU coatings prepared by the same method for Bayer Desmophen 670BA high solids hydroxyl polyester resin. It can be seen that the 2K-PU coating with star-shaped hydroxyl polyester has obvious advantages in terms of paint film hardness and VOC content under similar construction viscosity (about 22 s) compared with Desmophen 670 BA. The 2K-PU coating for spraying construction prepared by the formula has the construction solid content of 75 percent, the VOC content of less than 280g/L, the construction activation period of more than 24 hours, and the comprehensive performance of the coating meets the requirements of national standard GB/T23997-2009.
Compared with the patent application with publication numbers of CN102911349A and CN104262599A, the reaction temperature is lower than 120 ℃, benzene series such as dimethylbenzene is not used as a water carrying agent to promote the esterification reaction, dimethylbenzene is not caused to remain in a product, the increasingly severe environment-friendly requirement is met, and the method has the advantages of simple synthesis process, one-step feeding process, short reaction time consumption, energy conservation and emission reduction. Compared with the patent application with the publication number of CN 106279659A, the application efficiently reduces the viscosity of the resin and improves the construction solid content of the 2k-PU coating by compounding the reactive diluent with the star-shaped hydroxyl resin. In addition, a one-step feeding method is adopted in the synthesis method of the reactive diluent and the star-shaped hydroxyl polyester, the highest reaction temperature is 120 ℃ and is lower than 150 ℃ of the compared patent, caprolactone is not introduced into the product resin, the product resin is a low molecular weight star-shaped resin, the viscosity is low, and particularly the solid content of the prepared 2K-PU coating under the construction viscosity (30 mPa.s) is higher than 70%; the hydroxyl functionality is higher than 3, the hardness of a coating film is guaranteed to be up to 2H, the activation period is 24H, the VOC content of the coating is below 300g/L, and the coating has excellent gloss retention, color retention and weather resistance, thereby meeting the practical application of automobile coatings, particularly repair paints.
Example 2
1. Preparation of hydroxy resins
Preparation of Star hydroxyl polyester: 92.06g (1 mol) of glycerin, 148.12g (1 mol) of phthalic anhydride and 92.52g (1 mol) of epichlorohydrin are added into a reaction kettle, 0.185g (0.2% of the mass of epichlorohydrin) of tetraethylammonium bromide serving as a catalyst is added, the temperature is raised, the temperature is kept between 90 ℃ and 110 ℃ for reaction for 4 hours until the acid value is lower than 10mgKOH/g, and then the star-shaped hydroxyl polyester resin is obtained after cooling and discharging.
Preparation of reactive diluent: 134.13g (1 mol) of dimethylolpropionic acid, 92.52g (1 mol) of epichlorohydrin and 0.09g (0.1% of the mass of epichlorohydrin) of tetrabutylammonium bromide serving as a catalyst are added into a reactor to react for 4 hours at 90-110 ℃ until the acid value reaches below 5mgKOH/g, and then the reactive diluent is obtained after cooling and discharging.
Preparation of high solids content hydroxyl resins: mixing the prepared star-shaped hydroxyl polyester and reactive diluent according to the mass ratio of 3:1, and adding a proper amount of dipropylene glycol methyl ether acetate to adjust the solid content of the hydroxyl polyester to 80%, wherein the performance is as follows: the viscosity (25 ℃) of the water white transparent liquid is 1200mpa.s; acid value 4.3mgKOH/g; OH% = 7.5%.
2. Preparation of improved two-component polyurethane coating
The formulation of the improved two-component polyurethane coating of this example is shown in Table 3 below:
TABLE 3 Table 3
Sequentially adding hydroxyl polyester, a solvent, a leveling agent, a defoaming agent and a polyurethane (polyisocyanate) curing agent into a material dispersing cylinder according to the formula of the table 3, stirring for 5-10 min at a rotating speed of 1000-500 r/min by using a GFJ-0.4 high-speed dispersing machine to obtain a uniformly mixed bi-component polyurethane coating, standing, and preparing a coating film on a glass plate by using a 50 mu m wet film coater after bubbles escape so as to test the hardness of the coating film; the gloss, adhesion, flexibility, impact resistance, chemical resistance and the like of the cured paint film were tested after 7 days of curing at room temperature by spraying on a wood board and a tin plate with a W-77-3G gravity spray gun (nozzle diameter 2.5mm, japanese ANEST IWATA Co.). The VOC content of the paint construction was tested according to GB/T23985-2009. The paint pot life was tested using NK-2 type rock Tian Niandu cup (Japanese ANEST IWATA Co.). The film properties are shown in Table 4 below:
TABLE 4 Table 4
The infrared spectrum of the star-shaped hydroxyl resin prepared in this example is shown in figure 2.
Example 3
1. Preparation of hydroxy resins
Preparation of Star hydroxyl polyester: 134.17g (1 mol) of trimethylolpropane, 300.21g (3 mol) of succinic anhydride and 222.24g (3 mol) of glycidol are added into a reaction kettle, 0.11g (0.05% of the mass of glycidol) of tetrabutylammonium bromide serving as a catalyst is added, the temperature is raised, the reaction is kept at 90-110 ℃ for 4 hours until the acid value is lower than 10mgKOH/g, and then the star-shaped hydroxyl polyester resin is obtained after cooling and discharging.
Preparation of reactive diluent: 148.16g (1 mol) of dimethylolbutyric acid and 74.08g (1 mol) of glycidol are mixed with 33.33%, 0.11g of tetraethylammonium bromide serving as a catalyst with the mass of glycidol is added, and the mixture is reacted for 4 hours at the temperature of 90-110 ℃ until the acid value is below 5mgKOH/g, and then the mixture is cooled and discharged to obtain the active diluent;
preparation of high solids content hydroxyl resins: mixing the prepared star-shaped hydroxyl polyester and reactive diluent according to the mass ratio of 2:1, and adding a proper amount of dipropylene glycol methyl ether acetate to adjust the solid content of the hydroxyl polyester to 80%, wherein the performance is as follows: a water white transparent liquid, a viscosity (25 ℃) of 400mPa.s; acid value 4.5mgKOH/g; OH% = 6.5%;
2. preparation of improved two-component polyurethane coating
The formulation of the improved two-component polyurethane coating of this example is shown in Table 5 below:
TABLE 5
Sequentially adding high-solid content hydroxyl polyester, a solvent, a leveling agent, a defoaming agent and a polyurethane (polyisocyanate) curing agent into a material dispersing cylinder according to the formula of the table 5, stirring for 5-10 min at a rotating speed of 1000-500 r/min by using a GFJ-0.4 type high-speed dispersing machine to obtain a uniformly mixed bi-component polyurethane coating, standing, and preparing a coating film on a glass plate by using a 50 mu m wet film coater after bubbles escape so as to test the hardness of the coating film; the gloss, adhesion, flexibility, impact resistance, chemical resistance and the like of the cured paint film were tested after 7 days of curing at room temperature by spraying on a wood board and a tin plate with a W-77-3G gravity spray gun (nozzle diameter 2.5mm, japanese ANEST IWATA Co.). The VOC content of the paint construction was tested according to GB/T23985-2009. The paint construction activation period was tested using NK-2 rock Tian Niandu cup (Japanese ANEST IWATA Co.) with the results given in Table 6 below:
TABLE 6
Example 4
1. Preparation of hydroxy resins
Preparation of Star hydroxyl polyester: 136.15g (1 mol) of pentaerythritol, 168.19g (1 mol) of hexahydrophthalic anhydride and 130.23g (1 mol) of butyl glycidyl ether are added into a reaction kettle, 0.13g (0.1% of the mass of butyl glycidyl ether) of tetraethylammonium bromide serving as a catalyst is added, the temperature is increased, the temperature is kept between 90 and 110 ℃ for reaction for 4 hours until the acid value is lower than 10mgKOH/g, and then the star-shaped hydroxyl polyester resin is obtained after cooling and discharging.
Preparation of reactive diluent: 150.09g (1 mol) of tartaric acid and 164.20g (1 mol) of benzyl glycidyl ether are mixed, 0.08g (0.05% of the mass of benzyl glycidyl ether) of tetrabutylammonium bromide serving as a catalyst is added into a reactor, and the mixture is reacted for 4 hours at 90-110 ℃ until the acid value is below 5mgKOH/g, and then the mixture is cooled and discharged, thus obtaining the active diluent.
Preparation of high solids content hydroxyl resins: mixing the prepared star-shaped hydroxyl polyester and reactive diluent according to the mass ratio of 1:1, and adding a proper amount of dipropylene glycol methyl ether acetate to adjust the solid content of the hydroxyl polyester to 80%, wherein the performance is as follows: water white transparent liquid with viscosity (25 ℃) of 360mPa.s; acid value 4.0mgKOH/g; OH% = 4.5%.
2. Preparation of improved two-component polyurethane coating
The formulation of the improved two-component polyurethane coating of this example is shown in Table 7 below:
TABLE 7
Sequentially adding high-solid-content hydroxyl polyester, a solvent, a leveling agent, a defoaming agent and a polyurethane (polyisocyanate) curing agent into a material dispersing cylinder according to the formula of the table 7, stirring for 5-10 min at a rotating speed of 1000-500 r/min by using a GFJ-0.4 type high-speed dispersing machine to obtain a uniformly mixed bi-component polyurethane coating, standing until bubbles escape, and preparing a coating film on a glass plate by using a 50 mu m wet film coater to test the hardness of the coating film; the gloss, adhesion, flexibility, impact resistance, chemical resistance and the like of the cured paint film were tested after 7 days of curing at room temperature by spraying on a wood board and a tin plate with a W-77-3G gravity spray gun (nozzle diameter 2.5mm, japanese ANEST IWATA Co.). The VOC content of the paint construction was tested according to GB/T23985-2009. The paint construction activation period was tested using NK-2 rock Tian Niandu cup (Japanese ANEST IWATA Co.) and the test results are shown in Table 8:
TABLE 8
Example 5
1. Preparation of hydroxy resins
Preparation of Star hydroxyl polyester: 254.28g (1 mol) of dipentaerythritol, 336.38g (2 mol) of methyl hexahydrophthalic anhydride and 372.58g (2 mol) of octyl glycidyl ether are added into a reaction kettle, 0.56g (0.15% of the mass of octyl glycidyl ether) of triphenylphosphine serving as a catalyst is added, the temperature is raised, the temperature is kept between 90 and 110 ℃ for reaction for 4 hours until the acid value is lower than 10mgKOH/g, and then the material is cooled and discharged, so that the solvent-free star-shaped hydroxyl polyester resin is obtained.
Preparation of reactive diluent: mixing 90.08g (1 mol) of lactic acid and 186.29g (1 mol) of octyl glycidyl ether, adding 0.09g of triphenylphosphine serving as a catalyst with the mass of 0.05% of octyl glycidyl ether, reacting at 90-110 ℃ for 4 hours until the acid value is below 5mgKOH/g, and cooling and discharging to obtain the active diluent.
Preparation of high solids content hydroxyl resins: mixing the prepared star-shaped hydroxyl polyester and reactive diluent according to the mass ratio of 0.5:1, and adding a proper amount of dipropylene glycol methyl ether acetate to adjust the solid content of the hydroxyl polyester to 80%, wherein the performance is as follows: water white transparent liquid, viscosity (25 ℃): 350mPa.s; acid value 5.0mgKOH/g; OH% = 4.0%.
2. Preparation of improved two-component polyurethane coating
The formulation of the improved two-component polyurethane coating of this example is shown in Table 9 below:
TABLE 9
Sequentially adding high-solid content hydroxyl polyester, a solvent, a leveling agent, a defoaming agent and a polyurethane (polyisocyanate) curing agent into a material dispersing cylinder according to the formula of the table 9, stirring for 5-10 min at a rotating speed of 1000-500 r/min by using a GFJ-0.4 type high-speed dispersing machine to obtain a uniformly mixed bi-component polyurethane coating, standing until bubbles escape, and preparing a coating film on a glass plate by using a 50 mu m wet film coater to test the hardness of the coating film; the gloss, adhesion, flexibility, impact resistance, chemical resistance and the like of the cured paint film were tested after 7 days of curing at room temperature by spraying on a wood board and a tin plate with a W-77-3G gravity spray gun (nozzle diameter 2.5mm, japanese ANEST IWATA Co.). The VOC content of the paint construction was tested according to GB/T23985-2009. The paint construction activation period was tested using NK-2 rock Tian Niandu cup (Japanese ANEST IWATA Co.) and the test results are shown in Table 10:
table 10
Example 6
1. Preparation of hydroxy resins
Preparation of Star hydroxyl polyester: adding 303 300g (1 mol) of trifunctional polyether N, 148.12g (1 mol) of phthalic anhydride and 74.08g (1 mol) of glycidol into a reaction kettle, adding 0.15g (0.2% of glycidol mass) of catalyst cetyl ammonium bromide, heating and keeping the temperature at 90-110 ℃ for reaction for 4 hours until the acid value is below 10mgKOH/g, and cooling and discharging to obtain the star-shaped hydroxyl polyester resin.
Preparation of reactive diluent: 134.13g (1 mol) of dimethylolpropionic acid and 164.20g (1 mol) of benzyl glycidyl ether are mixed, 0.33g (0.2% of the mass of benzyl glycidyl ether) of cetyl ammonium bromide serving as a catalyst is added into a reactor, and the mixture is reacted for 4 hours at 90-110 ℃ until the acid value is below 5mgKOH/g, and then the mixture is cooled and discharged, so that the reactive diluent is obtained.
Preparation of high solids content hydroxyl resins: mixing the prepared star-shaped hydroxyl polyester and reactive diluent according to the mass ratio of 0.25:1, and adding a proper amount of dipropylene glycol methyl ether acetate to adjust the solid content of the hydroxyl polyester to 80%, wherein the performance is as follows: water white transparent liquid with viscosity (25 ℃) of 1000mPa.s; acid value 5.0mgKOH/g; OH% = 3.5%.
2. Preparation of improved two-component polyurethane coating
The formulation of the improved two-component polyurethane coating of this example is shown in Table 11 below:
TABLE 11
Sequentially adding high-solid-content hydroxyl polyester, a solvent, a leveling agent, a defoaming agent and a polyurethane (polyisocyanate) curing agent into a material dispersing cylinder according to the formula of the table 11, stirring for 5-10 min at a rotating speed of 1000-500 r/min by using a GFJ-0.4 type high-speed dispersing machine to obtain a uniformly mixed bi-component polyurethane coating, standing until bubbles escape, and preparing a coating film on a glass plate by using a 50 mu m wet film coater to test the hardness of the coating film; the gloss, adhesion, flexibility, impact resistance, chemical resistance and the like of the cured paint film were tested after 7 days of curing at room temperature by spraying on a wood board and a tin plate with a W-77-3G gravity spray gun (nozzle diameter 2.5mm, japanese ANEST IWATA Co.). The VOC content of the paint construction was tested according to GB/T23985-2009. The paint construction activation period was tested using NK-2 rock Tian Niandu cup (Japanese ANEST IWATA Co.) and the test results are shown in Table 12:
table 12
Example 7
1. Preparation of hydroxy resins
The preparation process of the star hydroxyl polyester comprises the following steps: 250.33g (1 mol) of ditrimethylolpropane, 512.52g (4 mol) of adipic anhydride and 660.8g (4 mol) of benzyl glycidyl ether are added into a reaction kettle, 1.32g (0.2% of the mass of benzyl glycidyl ether) of tetraethylammonium bromide serving as a catalyst is added, the temperature is raised and kept at 90-110 ℃ for reaction for 4 hours until the acid value is below 10mgKOH/g, and then the material is cooled and discharged, so that the solvent-free star-shaped hydroxyl polyester resin is obtained.
Preparation of reactive diluent: 148.16g (1 mol) of dimethylolbutyric acid, 92.52g (1 mol) of epichlorohydrin and 0.18g (0.2% of the mass of epichlorohydrin) of tetraethylammonium bromide serving as a catalyst are added into a reactor to react for 4 hours at 90-110 ℃ until the acid value reaches below 5mgKOH/g, and then the reactive diluent is obtained after cooling and discharging.
Preparation of high solids content hydroxyl resins: mixing the prepared star-shaped hydroxyl polyester and reactive diluent according to the mass ratio of 0.25:1, and adding a proper amount of dipropylene glycol methyl ether acetate to adjust the solid content of the hydroxyl polyester to 80%, wherein the performance is as follows: the viscosity (25 ℃) of the water white transparent liquid is 1500 Pa.s; acid value 5.0mgKOH/g; OH% = 3.0%.
2. Preparation of improved two-component polyurethane coating
The formulation of the improved two-component polyurethane coating of this example is shown in Table 13 below:
TABLE 13
Sequentially adding high-solid content hydroxyl polyester, a solvent, a leveling agent, a defoaming agent and a polyurethane (polyisocyanate) curing agent into a material dispersing cylinder according to the formula of the table 13, stirring for 5-10 min at a rotating speed of 1000-500 r/min by using a GFJ-0.4 type high-speed dispersing machine to obtain a uniformly mixed bi-component polyurethane coating, standing until bubbles escape, and preparing a coating film on a glass plate by using a 50 mu m wet film coater to test the hardness of the coating film; the gloss, adhesion, flexibility, impact resistance, chemical resistance and the like of the cured paint film were tested after 7 days of curing at room temperature by spraying on a wood board and a tin plate with a W-77-3G gravity spray gun (nozzle diameter 2.5mm, japanese ANEST IWATA Co.). The VOC content of the paint construction was tested according to GB/T23985-2009. The paint construction activation period was tested using NK-2 rock Tian Niandu cup (Japanese ANEST IWATA Co.) and the test results are shown in Table 14:
TABLE 14
Example 8
1. Preparation of hydroxy resins
Preparing star hydroxyl polyester: 254.28g (1 mol) of dipentaerythritol, 684.6g (6 mol) of glutaric anhydride and 555.12g (6 mol) of epichlorohydrin are added into a reaction kettle, 1.11g (0.2% of the mass of epichlorohydrin) of tetraethylammonium bromide serving as a catalyst is added, the temperature is raised, the reaction is kept at 90-110 ℃ for 4 hours until the acid value is lower than 10mgKOH/g, and then the star-shaped hydroxyl polyester resin is obtained after cooling and discharging.
Preparation of reactive diluent: 148.16g (1 mol) of dimethylolbutyric acid and 130.23g (1 mol) of butyl glycidyl ether are mixed, 0.26g (0.2% of the mass of butyl glycidyl ether) of tetraethylammonium bromide serving as a catalyst is added into a reactor, and the mixture is reacted for 4 hours at 90-110 ℃ until the acid value is below 5mgKOH/g, and then the mixture is cooled and discharged, so that the active diluent is obtained.
Preparation of high solids content hydroxyl resins: mixing the prepared star-shaped hydroxyl polyester and reactive diluent according to the mass ratio of 0.25:1, and adding a proper amount of dipropylene glycol methyl ether acetate to adjust the solid content of the hydroxyl polyester to 80%, wherein the performance is as follows: water white transparent liquid, viscosity (25 ℃) 800mPa.s; an acid value of 3.5mgKOH/g; OH% = 4.5%.
2. Preparation of improved two-component polyurethane coating
The formulation of the improved two-component polyurethane coating of this example is shown in Table 15 below:
TABLE 15
Sequentially adding high-solid-content hydroxyl polyester, a solvent, a leveling agent, a defoaming agent and a polyurethane (polyisocyanate) curing agent into a material dispersing cylinder according to the formula amount, stirring for 5-10 min at a rotating speed of 1000-500 r/min by using a GFJ-0.4 type high-speed dispersing machine to obtain a uniformly mixed bi-component polyurethane coating, standing, and preparing a coating film on a glass plate by using a 50 mu m wet film coater after bubbles escape so as to test the hardness of the coating film; the gloss, adhesion, flexibility, impact resistance, chemical resistance and the like of the cured paint film were tested after 7 days of curing at room temperature by spraying on a wood board and a tin plate with a W-77-3G gravity spray gun (nozzle diameter 2.5mm, japanese ANEST IWATA Co.). The VOC content of the paint construction was tested according to GB/T23985-2009. The paint pot life was tested using NK-2 rock Tian Niandu cup (Japanese ANEST IWATA Co.) and the test results are shown in Table 16:
table 16
Claims (1)
1. The improved two-component polyurethane coating comprises a hydroxyl component and a polyurethane curing agent component, wherein the hydroxyl component consists of hydroxyl resin and a coating auxiliary agent, and is characterized in that the hydroxyl resin is prepared by mixing star-shaped hydroxyl polyester and a reactive diluent according to the mass ratio of star-shaped hydroxyl polyester to reactive diluent = 0.25-4:1; wherein,
the star hydroxyl polyester is prepared by the following steps:
mixing polyalcohol, anhydride with the molar quantity of 1-6 times of that of the polyalcohol and monoepoxide with the molar quantity of the anhydride, adding a catalyst accounting for 0.05-0.2% of the mass of the monoepoxide, uniformly stirring, reacting at 90-110 ℃ until the acid value reaches 2-10mgKOH/g, and cooling to room temperature to obtain the star-shaped hydroxyl polyester;
the reactive diluent is prepared by the following method: mixing hydroxycarboxylic acid and a monoepoxide compound with the same molar weight as the hydroxycarboxylic acid, adding a catalyst according to the mass of 0.05-0.2% of the monoepoxide compound, reacting at 90-120 ℃ until the acid value reaches 2-5mgKOH/g, and cooling to room temperature to obtain the active diluent;
the anhydride is one of phthalic anhydride, hexahydrophthalic anhydride, methyl hexahydrophthalic anhydride, adipic anhydride and glutaric anhydride;
the polyalcohol is one of pentaerythritol, ditrimethylolpropane and dipentaerythritol;
the monoepoxide compound is one of epichlorohydrin, glycidol, butyl glycidyl ether, benzyl glycidyl ether and octyl glycidyl ether;
the hydroxy carboxylic acid is one of dihydroxymethyl butyric acid and tartaric acid;
the catalyst is one of tetraethylammonium bromide, tetrabutylammonium bromide and triphenylphosphine.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4314918A (en) * | 1980-06-26 | 1982-02-09 | Ppg Industries, Inc. | Coating compositions containing organic alcoholic reactive diluents |
| CN106432703A (en) * | 2016-09-26 | 2017-02-22 | 华南理工大学 | Hydroxyl polyester resin with high solid content and preparation method and application thereof |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4314918A (en) * | 1980-06-26 | 1982-02-09 | Ppg Industries, Inc. | Coating compositions containing organic alcoholic reactive diluents |
| CN106432703A (en) * | 2016-09-26 | 2017-02-22 | 华南理工大学 | Hydroxyl polyester resin with high solid content and preparation method and application thereof |
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