CN116239755A - Polyisocyanate composition with high reactivity and preparation method thereof - Google Patents
Polyisocyanate composition with high reactivity and preparation method thereof Download PDFInfo
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- CN116239755A CN116239755A CN202310001904.5A CN202310001904A CN116239755A CN 116239755 A CN116239755 A CN 116239755A CN 202310001904 A CN202310001904 A CN 202310001904A CN 116239755 A CN116239755 A CN 116239755A
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- 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
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
- C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
- C08G18/7657—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings
- C08G18/7664—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups
- C08G18/7671—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups containing only one alkylene bisphenyl group
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- 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
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/721—Two or more polyisocyanates not provided for in one single group C08G18/73 - C08G18/80
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- 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
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
- C08G18/78—Nitrogen
- C08G18/79—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates
- C08G18/791—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing isocyanurate groups
- C08G18/792—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing isocyanurate groups formed by oligomerisation of aliphatic and/or cycloaliphatic isocyanates or isothiocyanates
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- 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
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Abstract
The invention provides a polyisocyanate composition with high reactivity and a preparation method thereof. The polyisocyanate composition has the following characteristics: the polyisocyanate composition comprises isocyanurate formed by trimerization reaction of xylylene diisocyanate and aliphatic diisocyanate, and the composition simultaneously comprises three isocyanurate mononucleosomes with structures (I), (II) and (III), and the mass ratio of the three mononucleosomes satisfies the following relation based on the total mass of the isocyanate composition: (II) < (I) < (III). The polyisocyanate composition prepared by the invention has the characteristics of high reactivity, high glossiness of a paint film after curing, and the like, and the preparation process is simple, and is particularly suitable for the fields of automobile repair paint with certain requirements on construction period and weather resistance, and the like.
Description
Technical Field
The invention belongs to the field of high polymer coating, and in particular relates to a polyisocyanate composition with high reactivity and a preparation method thereof.
Background
Polyurethane coating film formed by reacting isocyanate curing agent with polyalcohol has good wear resistance, toughness and easy processing property, so the polyurethane coating film is widely applied to various fields of automobile coating, household appliances, toys, leather inner decorations and the like. The traditional coating film prepared from the aromatic isocyanate series has higher reactivity in the curing process, but with the prolonged service time, the product is easy to generate yellowing or chalking phenomena with different degrees. The aliphatic isocyanate series composition has more excellent yellowing resistance, and the product is more applied to the field with higher weather resistance requirement, but the reactivity of the aliphatic isocyanate is poor, so that the product has longer drying time, thereby influencing the construction efficiency and progress.
In order to ensure that downstream customers can realize rapid solidification during application, CN101619194 improves the reaction speed of hexamethylene isocyanurate and hydroxy acrylic resin and shortens the drying time of products by adding high-hydroxyl-value reactive cellulose acetate butyrate and adding an organotin catalyst for polyurethane, and the method has a certain effect, but the dosages of the cellulose acetate butyrate and the tin catalyst are difficult to balance between the mechanical stability and quick-drying performance of the products, and the application field is limited. CN101812261 is obtained by physically blending 80% of 1, 6-hexamethylene diisocyanate trimer and 20% of isophorone diisocyanate or quick-drying 1, 6-hexamethylene diisocyanate trimer, and then using as an isocyanate curing agent to increase the drying speed of the product, essentially by using physical blending as a method for improving the quick-drying property of the product, the method requires pre-mixing treatment, and the reactivity of isophorone diisocyanate or quick-drying 1, 6-hexamethylene diisocyanate trimer can be improved only to a limited extent. DE19752691 uses polyisocyanates based on isophorone diisocyanate and polyisocyanates based on pentamethylene diisocyanate in cold-mix form to improve certain properties of the polyisocyanates, also belonging to physical modification, and it is more difficult to achieve high gloss due to chemical bond linkages. US6472493B1 prepares a quick-drying curing agent, and mainly shortens the construction time and the service life of the curing agent by adding amine catalysts and carboxylic acid catalysts, so that a paint film is easy to generate yellowing, scratch, poor adhesive force and the like in the later use process.
Therefore, development of a highly reactive isocyanate curing agent excellent in performance has been a problem to be solved.
Disclosure of Invention
Therefore, the invention aims to overcome the defects in the prior art and provide a polyisocyanate composition and a preparation method thereof, which not only improve the reactivity of an aliphatic isocyanate curing agent, shorten the construction period in application, but also improve the adhesive force of a obviously formed paint film to a plastic substrate (PMMA) or a metal substrate of an automobile.
The invention is realized by the following technical scheme: in a first aspect, the present invention provides a highly reactive polyisocyanate composition.
The polyisocyanate composition comprises isocyanurate formed by trimerization reaction of xylylene diisocyanate and aliphatic diisocyanate, and the composition simultaneously comprises three isocyanurate mononucleus bodies with structures (I), (II) and (III), wherein the mole ratio of the three mononucleus bodies satisfies the following relation: (II) < (I) < (III).
Wherein R is 1 Residual structure after removal of isocyanate groups for 1,6 hexamethylene diisocyanate, 1, 5-pentanediisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate or bis (isocyanatomethyl) norbornane.
The polyisocyanate composition provided by the invention adopts the structure of aliphatic diisocyanate and xylylene diisocyanate, which have good weather resistance, while xylylene has two NCO groups with higher reactivity, and through a unique gradual copolymerization process of isocyanurate, on one hand, the modified aliphatic diisocyanate trimer has free NCO groups with higher reactivity, and the drying speed is obviously improved. On the other hand, the inventors have surprisingly found that the asymmetric structure of the modified isocyanurate ring formed by the xylylene diisocyanate and the aliphatic diisocyanate is increased, so that the curing agent is not easy to cause symmetric shrinkage when the curing agent is crosslinked and cured on the surface of the substrate, and the adhesion of the curing agent on the surface of the metal substrate or the plastic substrate is obviously improved.
Further, the ratio of modified isocyanurate mononucleosome structure (II)/structure (I) in the polyisocyanate composition is between 5% and 30%, preferably between 5% and 15%.
The inventors have unexpectedly found that by controlling the isocyanurate mononucleosome structure (II)/structure (I) ratio, the depth of polymerization of xylylene diisocyanate together with aliphatic diisocyanate can be ensured. Controlling the isocyanurate mononucleus structure (II)/structure (I) ratio to be less than 30% can avoid forming unstable mixture due to excessive self-polymerization of high content of xylylene diisocyanate. Controlling the isocyanurate mononucleosome structure (II)/structure (I) ratio to be greater than 5% can ensure a short drying time of the final isocyanate composition. More importantly, it has been found that the two are sufficiently cross-polymerized and the structural ratio is ensured to be within the range of 5% to 30%, so that the finally obtained polyisocyanate composition can better maintain the isocyanate groups having high reactivity and the adhesion to the substrate.
Further, the polyisocyanate composition has a sum of free xylylene diisocyanate and aliphatic diisocyanate monomer content of less than 0.5% based on 100% by weight of the total isocyanate composition.
Further, the polyisocyanate composition wherein the xylylene isocyanate is composed of 1, 3-xylylene diisocyanate isomers in view of the ease of acquisition and production of industrial raw materials.
Further, the aliphatic diisocyanate is selected from one or more of 1,6 hexamethylene diisocyanate, 1, 5-pentanediisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, bis (isocyanatomethyl) norbornane, preferably 1,6 hexamethylene diisocyanate and/or 1, 5-pentanediisocyanate.
In a second aspect, the present invention further provides a process for preparing the above polyisocyanate composition comprising the steps of:
s1: adding aliphatic diisocyanate into a reaction vessel, heating, adding a catalyst, adding xylylene diisocyanate, and carrying out continuous copolymerization reaction;
s2: after the addition of the xylylene diisocyanate is completed, continuing to react to the target polymerization conversion rate of the aliphatic diisocyanate, adding a terminator to terminate the reaction to obtain an isocyanate mixture solution, and removing unreacted aliphatic diisocyanate and xylylene diisocyanate to obtain the polyisocyanate composition.
Further, in S1, the accumulated addition mass content of the xylylene diisocyanate is 4-20% based on the total mass of the xylylene diisocyanate and the aliphatic diisocyanate.
Further, dropwise adding the xylylene diisocyanate in the step S1; preferably, the dropping rate of the xylylene diisocyanate is not particularly limited, and the dropping time is preferably controlled to 50 to 100 minutes.
Further, the catalyst in S1 is not particularly limited, and a catalyst that can catalyze both xylylene diisocyanate and aliphatic diisocyanate is preferable, and one or more of trimethylhydroxyethyl ammonium, triethylhydroxypropyl ammonium, tetramethyl ammonium acetate, tetrabutyl ammonium acetate, tetramethyl ammonium propionate, tetramethyl ammonium hydroxide, benzyltrimethyl ammonium hydroxide, benzyltriphenyl phosphorus chloride, 2,4, 6-tris (dimethylaminomethyl) phenol is more preferable.
Further, S1 is performed under an inert gas atmosphere.
Further, the temperature is raised to 40-120 ℃ in S1.
Further, when the polymerization conversion rate of the aliphatic diisocyanate obtained by the reaction in S2 reaches 35 to 65%, preferably 40 to 50%, the reaction is terminated by adding a terminator.
Further, unreacted aliphatic diisocyanate and xylylene diisocyanate are removed by distillation in S2.
Further, the terminator is an acid compound, preferably one or more of dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, 2-ethylhexyl phosphate, phosphoric acid, hydrochloric acid, benzenesulfonic acid, p-toluenesulfonic acid, benzoyl chloride and acetyl chloride.
It is still another object of the present invention to provide a polyurethane resin.
The polyurethane resin is formed by mixing a polyisocyanate composition serving as an isocyanate-containing component and a hydroxyl-containing acrylic resin serving as a polyol component according to the molar equivalent of NCO and OH value of 1.0-1.1. Whether the inert solvent is added for dilution can be selected according to the actual working condition.
Further, the inert solvent may be selected from at least two of acetone, ethyl acetate, butyl acetate, propylene glycol methyl ether acetate, xylene, S100 solvent oil, preferably ethyl acetate, butyl acetate, propylene glycol methyl ether acetate.
It is a further object of the present invention to provide a polyurethane composite.
The polyurethane composite material is obtained by coating polyurethane resin on the surface of a metal substrate and/or plastic. The metal substrate is preferably selected from Q235 type steel plate substrates, and the plastic substrate is selected from polymethyl methacrylate plates.
The technical scheme provided by the invention has the following beneficial effects:
in the process of preparing modified aliphatic diisocyanate isocyanurate, the benzene dimethylene diisocyanate is continuously dripped into the aliphatic diisocyanate to carry out copolymerization, the structural content proportion of modified isocyanurate mononucleus bodies (I) and (II) in a reaction system is further controlled, and finally, a modified isocyanate composition reaction solution is obtained, and unreacted aliphatic diisocyanate and the benzene dimethylene diisocyanate are further removed, so that an isocyanate composition is obtained.
Detailed Description
For a better understanding of the technical solution of the present invention, the following examples are further described below, but the present invention is not limited to the following examples.
The following examples and comparative examples of the present invention were prepared from the following raw materials in part by sources:
xylylene Diisocyanate (XDI), specifically 1,3 xylylene diisocyanate isomer, available from vancomic chemical group inc;
1, 6-Hexamethylene Diisocyanate (HDI) available from Wanhua chemical group Co., ltd;
isophorone diisocyanate (IPDI), available from vancomic chemical group inc;
T 12 dibutyl tin dilaurate, a common drier for polyurethane resins, available from Nanjing Ai Dewang, inc.;
tetrabutylammonium hydroxide, isocyanurate catalyst, available from Ying Chuang chemical industry Co., ltd;
tetramethylammonium hydroxide, isocyanurate catalyst, available from the winning chemical industry Co., ltd;
benzyl trimethylammonium hydroxide, isocyanurate catalyst, available from New classical chemical Co., ltd;
dioctyl phosphate, isocyanurate terminator, available from Tianjin Yongda chemical Co., ltd;
dimethyl phosphate, isocyanurate terminator, available from Tianjin Yongda chemical Co., ltd;
polymethyl methacrylate (PMMA) sheet, 0.5mm thick, available from daggeda instruments inc;
q235 substrate steel plate, 3mm thick, available from Bidada instruments Co., ltd;
ethyl acetate, 99.8% pure, for polyurethane resin solvent, available from ala Ding Shiji, inc;
butyl acetate, 99.8% pure, for polyurethane resin solvent, available from ala Ding Shiji, inc;
malonic methyl ether acetate with a purity of 99.8%, for polyurethane resin solvents, available from Ala Ding Shiji Co., ltd;
unless otherwise specified, the contents in the present invention are mass contents.
In the following examples and comparative examples of the present invention, the relevant test methods are as follows:
(1) NCO content tests were carried out according to standard GB/T12009.4;
(2) The isocyanurate mononuclear body structure test method is as follows:
AVANCE400 manufactured by Bruker Biospin was used as CDCl in deuterated chloroform 3 The 13C nuclear magnetic resonance spectrum was measured as solvent at 60% by mass concentration of the sample (produced isocyanurate product), 100MHz, and scanning overnight.
In the above measurement, the following characteristic signals were integrated, and the mass ratios of the respective structures (I), (II), and (III) were obtained from the integrated values.
(a) A structure of formula I: delta 148.3ppm vicinity
(b) A structure of formula II: delta 150.7ppm vicinity
(c) A structure of formula III: delta 148.6ppm vicinity
(d) (formula II)/(formula I) mass ratio: (formula II)/(formula I) = (signal area of formula II)/(signal area of formula I).
(3) The sum of the monomer contents of free-form xylylene diisocyanate and aliphatic diisocyanate is tested, an external standard curve is established by adopting High Performance Liquid Chromatography (HPLC), and the key parameters can be referred to as follows:
chromatographic column: waters XSelect HSS T3 5um 4.6 x 250mm;
automatic sample injector: SIL-20A
Column temperature: 40 DEG C
Sample injection amount: 10 mu L
Detection wavelength: 281nm
Derivatizing reagent: 4% 1-methoxyphenylpiperazine-acetonitrile solution.
The respective concentrations are calculated according to the respective peak areas and external standard curves of the xylylene diisocyanate and the aliphatic diisocyanate, and the sum of the two concentrations is taken as the sum of the monomer contents of the free xylylene diisocyanate and the aliphatic diisocyanate in the polyisocyanate composition.
Preparation of the polyisocyanate composition:
[ example 1 ]
The method for preparing the polyisocyanate composition comprises the following steps: under the nitrogen atmosphere, 1000g of 1, 6-hexamethylene diisocyanate is firstly added into a reaction vessel and heated to 60 ℃, then 0.18g of tetrabutylammonium hydroxide catalyst is added, simultaneously, the continuous dropwise addition of the xylylene diisocyanate is adopted, the continuous copolymerization reaction is carried out under the action of the catalyst, the dropwise addition is stopped after the continuous accumulation of the xylylene diisocyanate is controlled to be 250g for 80 minutes, the reaction rate is continuously maintained until the polymerization conversion rate of the 1, 6-hexamethylene diisocyanate reaches 65%, 0.14g of dioctyl phosphate terminator is added to stop the reaction, the isocyanate mixture solution is obtained, and unreacted 1, 6-hexamethylene diisocyanate and xylylene diisocyanate are further removed by two-stage film evaporation, wherein the conditions of the first-stage film evaporation are as follows: the temperature is 135 ℃ and the vacuum degree is 10Pa; the conditions for the second stage thin film evaporation were: the temperature was 145℃and the degree of vacuum was 10Pa, to obtain a polyisocyanate composition No. 1, which was analyzed to have an NCO content of 21.0% and a sum of monomer contents of 1, 6-hexamethylene diisocyanate and hydrogenated xylylene diisocyanate in a free state of 0.42% based on 100% by weight of the total isocyanate composition.
[ example 2 ]
The method for preparing the polyisocyanate composition comprises the following steps: under the nitrogen atmosphere, 1000g of 1, 6-hexamethylene diisocyanate is firstly added into a reaction vessel and heated to 60 ℃, then 0.17g of tetrabutylammonium hydroxide catalyst is added, simultaneously, the continuous dropwise addition of the xylylene diisocyanate is adopted, the continuous copolymerization reaction is carried out under the action of the catalyst, the dropwise addition is stopped after the continuous accumulation of the xylylene diisocyanate is controlled for 60 minutes to be 150g, the reaction rate is continuously maintained until the polymerization conversion rate of the 1, 6-hexamethylene diisocyanate reaches 60%, 0.12g of dioctyl phosphate terminator is added to stop the reaction, the isocyanate mixture solution is obtained, and unreacted 1, 6-hexamethylene diisocyanate and xylylene diisocyanate are further removed by two-stage film evaporation, wherein the conditions of the first-stage film evaporation are as follows: the temperature is 140 ℃ and the vacuum degree is 10Pa; the conditions for the second stage thin film evaporation were: the temperature was 150℃and the degree of vacuum was 10Pa, to obtain a polyisocyanate composition No. 2, which was analyzed to have an NCO content of 21.2% and a sum of monomer contents of 1, 6-hexamethylene diisocyanate and hydrogenated xylylene diisocyanate in a free state of 0.38% based on 100% by weight of the total isocyanate composition.
[ example 3 ]
The method for preparing the polyisocyanate composition comprises the following steps: under the nitrogen atmosphere, 1000g of 1, 6-hexamethylene diisocyanate is firstly added into a reaction vessel and heated to 90 ℃, then 0.15g of benzyltrimethylammonium hydroxide catalyst is added, simultaneously, the continuous dropwise addition of the xylylene diisocyanate is adopted, the continuous copolymerization reaction is carried out under the action of the catalyst, the dropwise addition is stopped after the continuous accumulation of the xylylene diisocyanate is controlled to be 50g for 50 minutes, the reaction rate is continuously maintained until the polymerization conversion rate of the 1, 6-hexamethylene diisocyanate reaches 50, 0.11g of dioctyl phosphate terminator is added to stop the reaction, the isocyanate mixture solution is obtained, and unreacted 1, 6-hexamethylene diisocyanate and xylylene diisocyanate are further removed by two-stage film evaporation, wherein the conditions of the first-stage film evaporation are as follows: the temperature is 145 ℃ and the vacuum degree is 10Pa; the conditions for the second stage thin film evaporation were: the temperature was 155℃and the degree of vacuum was 20Pa, to obtain a polyisocyanate composition 3#, which was analyzed to have an NCO content of 21.5% and a sum of monomer contents of 1, 6-hexamethylene diisocyanate and hydrogenated xylylene diisocyanate in a free state of 0.41% based on 100% by weight of the total isocyanate composition.
[ example 4 ]
The method for preparing the polyisocyanate composition comprises the following steps: under the nitrogen atmosphere, 1000g of isophorone diisocyanate is firstly added into a reaction vessel and heated to 120 ℃, then 0.18g of tetramethylammonium hydroxide catalyst is added, meanwhile, the continuous dropwise addition of the xylylene diisocyanate is adopted, continuous copolymerization reaction is carried out under the action of the catalyst, the dropwise addition is stopped after the continuous accumulation of the xylylene diisocyanate is controlled to be 150g for 100 minutes, the reaction rate is continuously maintained until the polymerization conversion rate of isophorone diisocyanate reaches 40%, 0.14g of dimethyl phosphate terminator is added to stop the reaction, an isocyanate mixture solution is obtained, unreacted isophorone diisocyanate and xylylene diisocyanate are further removed through two-stage film evaporation, and the conditions of first-stage film evaporation are as follows: the temperature is 140 ℃ and the vacuum degree is 50Pa; the conditions for the second stage thin film evaporation were: the temperature was 150℃and the degree of vacuum was 20Pa, to obtain a polyisocyanate composition No. 4, which was analyzed to have an NCO content of 18.5% and a sum of the monomer contents of isophorone diisocyanate and hydrogenated xylylene diisocyanate in a free state of 0.35% based on 100% by weight of the total isocyanate composition.
Comparative example 1
The difference compared with example 1 was that the amount of xylylene diisocyanate added dropwise was 0g, to give polyisocyanate composition # 5, which was found to have an NCO content of 21.7% and a free 1, 6-hexamethylene diisocyanate content of 0.37% based on 100% by mass of the total isocyanate composition.
Comparative example 2
The difference compared with example 1 was that the mass of the added xylylene diisocyanate was 460g, to obtain polyisocyanate composition 6#, and the NCO content of the polyisocyanate composition was 20.5% and the sum of the monomer contents of free 1, 6-hexamethylene diisocyanate and hydrogenated xylylene diisocyanate was 0.39% based on 100% of the total mass of the isocyanate composition.
[ comparative example 3 ]
The preparation method of the polyisocyanate composition of the present example comprises the following steps: under the inert gas atmosphere, 1000g of 1, 6-hexamethylene diisocyanate is firstly added into a reaction vessel and heated to 60 ℃, then 0.18g of tetrabutylammonium hydroxide catalyst is added, simultaneously, the continuous dropwise addition of the xylylene diisocyanate is adopted, the continuous copolymerization reaction is carried out under the action of the catalyst, the dropwise addition is stopped after the continuous accumulation of the xylylene diisocyanate is controlled to be 800g for 100 minutes, the reaction rate is continuously maintained until the polymerization conversion rate of the 1, 6-hexamethylene diisocyanate reaches 65%, 0.14g of dioctyl phosphate terminator is added to stop the reaction, the isocyanate mixture solution is obtained, the unreacted 1, 6-hexamethylene diisocyanate and the xylylene diisocyanate are further removed by two-stage film evaporation, and the conditions of the first-stage film evaporation are as follows: the temperature is 140 ℃ and the vacuum degree is 40Pa; the conditions for the second stage thin film evaporation were: the temperature was 150℃and the degree of vacuum was 30Pa, to obtain a polyisocyanate composition No. 7, which was analyzed to have an NCO content of 19.9% and a sum of monomer contents of 1, 6-hexamethylene diisocyanate and hydrogenated xylylene diisocyanate in a free state of 0.36% based on 100% by weight of the total isocyanate composition.
The polyisocyanate compositions prepared in each example and comparative example were analyzed for the content relationship of the structure (I), the structure (II) and the structure (III), and the analysis results are shown in Table 1:
TABLE 1 analysis of polyisocyanate compositions
| Project | Formula (III) ratio/% | Formula (II) ratio/% | The proportion of formula (I)/% | Structural relationship | The ratio of formula (II)/(I) |
| Example 1 | 31.5 | 4.1 | 9.7 | (II)<(I)<(III) | 28％ |
| Example 2 | 34.3 | 2.0 | 7.8 | (II)<(I)<(III) | 19％ |
| Example 3 | 39.5 | 0.5 | 5.9 | (II)<(I)<(III) | 8％ |
| Example 4 | 31.2 | 1.4 | 7.4 | (II)<(I)<(III) | 15％ |
| Comparative example 1 | 48.1 | 0 | 0 | —— | 0％ |
| Comparative example 2 | 18.2 | 14.0 | 12.9 | (I)<(II)<(III) | 52％ |
| Comparative example 3 | 13.0 | 20.8 | 11.2 | (III)<(I)<(II) | 65％ |
Examples of applications for the preparation of polyisocyanate compositions:
the above polyisocyanate compositions 1 to 7# were used as isocyanate components, hydroxyl-containing acrylic resin (trade name: AC1260, from Tongde resin) was used as polyol components, mixed in a ratio of isocyanate group/hydroxyl group molar ratio (NCO/OH) of 1.05, and diluted with a diluent (mixed components of ethyl acetate/propylene glycol methyl ether acetate/butyl acetate were mixed in a weight ratio of 1:1:1), and the coating composition was diluted to 50% by weight, stirred at 23℃for 5 minutes and sonicated for 5 minutes to obtain a defoamed polyurethane resin coating solution.
The polyurethane resin coating solution obtained by the above method was applied to a steel sheet (Q235 type) and a sheet of Polymethacrylate (PMMA) so that the dry film thickness was 40. Mu.m. Next, drying was performed at 23℃for 2 hours, and then heat treatment was performed at 80℃for 30 minutes. Then, the mixture was cured at 23℃and a relative humidity of 55% for 7 days.
(1) Touch dry time
The coating solution was applied to a glass plate using an applicator so as to have a thickness of 100 μm (thickness before drying), and after the application, the time until no longer sticking was observed when the glass plate was touched by hand at 23℃and a relative humidity of 30%.
(2) Curing drying time
The coating solution was applied to a glass plate using an applicator so as to have a thickness of 100 μm (thickness before drying), and after the application, the time until no fingerprint mark was left by being pressed with a finger with a strong force was measured at 23 ℃ under a relative humidity of 30%.
(3) Adhesion rating
The coated steel sheet metal substrate (type Q235) and plastic substrate (PMMA) based coated samples described above were tested for adhesion according to GB/T9286-1998 cross-hatch test of color paint and varnish film.
The polyisocyanate compositions prepared in each example and comparative example were subjected to application performance index test according to the application example description, and the test results are shown in table 2:
TABLE 2 polyisocyanate composition application Performance index
| Raw materials | Touch dry time/second | Curing drying time/min | Adhesion/metal base | Adhesion/plastic base |
| Example 1 | 113 | 103 | 0 | 1 |
| Example 2 | 138 | 126 | 1 | 2 |
| Example 3 | 157 | 135 | 1 | 2 |
| Example 4 | 121 | 112 | 1 | 2 |
| Comparative example 1 | 242 | 221 | 3 | 4 |
| Comparative example 2 | 100 | 93 | 4 | 5 |
| Comparative example 3 | 85 | 80 | 4 | 5 |
As can be seen from tables 1 and 2, the acrylic polyurethane resins prepared in examples 1 to 4 are excellent in performance indexes such as touch drying time, curing drying time and adhesive force, and are particularly suitable for the quick-drying fields such as automobile repair paint; the acrylic polyurethane resin sample sheets prepared in comparative examples 1-3 have obviously poor indexes and poor comprehensive properties, and are difficult to meet actual demands. It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the invention.
Claims (10)
1. A high-reactivity polyisocyanate composition is characterized in that the polyisocyanate composition comprises isocyanurate formed by trimerization reaction of xylylene diisocyanate and aliphatic diisocyanate, and the composition simultaneously comprises three isocyanurate mononucleus bodies with structures (I), (II) and (III), and the mass ratio of the three mononucleus bodies satisfies the following relation based on the total mass of the isocyanate composition: (II) < (I) < (III),
wherein R is 1 Is 1,6 hexamethylene diisocyanate and 1, 5-pentanediolOne or more of cyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate and bis (isocyanatomethyl) norbornane, and the residual structure after removal of the isocyanate group.
2. Polyisocyanate composition according to claim 1, characterized in that the mass ratio modified isocyanurate mononucleolar structure (II)/structure (I) ranges between 5% and 30%, preferably between 5% and 15%.
3. The polyisocyanate composition according to claim 1 or 2, wherein the sum of the monomer contents of free xylylene diisocyanate and aliphatic diisocyanate is less than 0.5% based on 100% by weight of the total isocyanate composition.
4. A polyisocyanate composition according to any one of claims 1 to 3 wherein the xylylene diisocyanate consists of 1, 3-xylylene diisocyanate isomers.
5. The polyisocyanate composition according to any one of claims 1 to 4, wherein the aliphatic diisocyanate is selected from one or more of 1,6 hexamethylene diisocyanate, 1, 5-pentanediisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, bis (isocyanatomethyl) norbornane, preferably 1,6 hexamethylene diisocyanate and/or 1, 5-pentanediisocyanate.
6. A process for preparing an isocyanate composition according to any one of claims 1 to 5, comprising the steps of:
s1: adding aliphatic diisocyanate into a reaction vessel, heating, adding a catalyst, adding xylylene diisocyanate, and carrying out continuous copolymerization reaction;
s2: after the addition of the xylylene diisocyanate is completed, continuing to react to the target polymerization conversion rate of the aliphatic diisocyanate, adding a terminator to terminate the reaction to obtain an isocyanate mixture solution, and removing unreacted aliphatic diisocyanate and xylylene diisocyanate to obtain the polyisocyanate composition.
7. The process for producing the polyisocyanate composition according to claim 6, wherein the cumulative added mass content of xylylene diisocyanate in S1 is 4% to 20% based on the total mass of xylylene diisocyanate and aliphatic diisocyanate;
and/or, dropwise adding the xylylene diisocyanate in the step S1;
preferably, the dropping rate of the xylylene diisocyanate is not particularly limited, and the dropping time is preferably controlled to be 50 to 100 minutes;
and/or, the catalyst in S1 is not particularly limited, and is preferably a catalyst that can catalyze both xylylene diisocyanate and aliphatic diisocyanate, more preferably one or more of trimethylhydroxyethylammonium, tetrabutylammonium hydroxide, triethylhydroxypropylammonium, tetramethylammonium acetate, tetrabutylammonium acetate, tetramethylammonium propionate, tetramethylammonium hydroxide, benzyltrimethylammonium hydroxide, benzyltriphenylphosphine chloride, 2,4, 6-tris (dimethylaminomethyl) phenol;
and/or, S1 is carried out under an inert gas atmosphere;
and/or, heating to 40-120 ℃ in S1.
8. The process for preparing the polyisocyanate composition according to claim 6, wherein the reaction is terminated by adding a terminator until the polymerization conversion of the aliphatic diisocyanate reaches 35 to 65%, preferably 40 to 50%, in S2;
and/or removing unreacted aliphatic diisocyanate and xylylene diisocyanate by distillation in S2.
9. A polyurethane resin prepared by mixing the isocyanate composition as claimed in any one of claims 1 to 8 as a curing agent with a polyol component in a ratio of 1 to 1.1 in terms of isocyanate group/hydroxyl group molar ratio (NCO/OH).
10. A polyurethane composite made from the polyurethane resin of claim 9 applied to a substrate, wherein the substrate is a surface of metal and/or plastic.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310001904.5A CN116239755A (en) | 2023-01-03 | 2023-01-03 | Polyisocyanate composition with high reactivity and preparation method thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310001904.5A CN116239755A (en) | 2023-01-03 | 2023-01-03 | Polyisocyanate composition with high reactivity and preparation method thereof |
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| CN116239755A true CN116239755A (en) | 2023-06-09 |
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- 2023-01-03 CN CN202310001904.5A patent/CN116239755A/en active Pending
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