CN114891448A

CN114891448A - Primer-free polyurethane sealant and preparation method and application thereof

Info

Publication number: CN114891448A
Application number: CN202210653908.7A
Authority: CN
Inventors: 孙辉; 孟君伟; 周朝栋; 杨波; 陶小乐; 何永富
Original assignee: Hangzhou Zhijiang Silicone Chemicals Co Ltd
Current assignee: Hangzhou Zhijiang Silicone Chemicals Co Ltd
Priority date: 2022-06-09
Filing date: 2022-06-09
Publication date: 2022-08-12
Anticipated expiration: 2042-06-09
Also published as: CN114891448B

Abstract

The invention provides a primer-free polyurethane sealant and a preparation method and application thereof, belonging to the technical field of adhesive materials. The invention provides a primer-free polyurethane sealant which is prepared from the following raw materials in percentage by mass: 30-50% of polyurethane polymer, 0.5-2% of isocyanate, 10-30% of plasticizer, 10-30% of filler, 10-30% of carbon black, 0.2-0.5% of water absorbent, 0.2-0.5% of long carbon chain silane coupling agent, 0.2-2% of acrylate monomer, 0.01-0.1% of tertiary amine catalyst and 0.01-0.05% of organic tin catalyst. According to the invention, the polyurethane polymer and isocyanate are used as raw materials, and under the composite action of the tertiary amine catalyst and the organic tin catalyst, the primer-free adhesive property of the paint surface is improved; the long carbon chain silane coupling agent and the acrylate monomer are used together to improve the primer-free bonding performance of various substrates.

Description

Primer-free polyurethane sealant and preparation method and application thereof

Technical Field

The invention belongs to the technical field of adhesive materials, and particularly relates to a primer-free polyurethane sealant as well as a preparation method and application thereof.

Background

The single-component polyurethane windshield glass adhesive is a polyurethane adhesive which takes a polymer blocked by isocyanate (NCO) groups as a main effective component and is matched with a plasticizer, a filler, a catalyst and an auxiliary agent. Because the NCO group has poor bonding force on plastic substrates such as white glass, ink glass, vehicle body paint, aluminum alloy, PA6/PBT/PP and the like, the market basically solves the bonding requirement on various substrates through two schemes: 1. the primer special for the base material is adopted, the method has good bonding effect, but the construction procedures of automobile factories need to be increased, and the volatilization of the solvent of the primer has the adverse effect of influencing the health of workers; 2. the adhesion force to white glass and ink glass can be improved by adding a tackifier such as a silane coupling agent into polyurethane glue, but the adhesion of plastic substrates such as automobile body paint, aluminum alloy, PA/PBT/PP and the like cannot be met.

For example, patent CN1730594 discloses a direct-bonding polyurethane sealant, wherein the adopted coupling agents are commercial silane coupling agents, the direct addition of the coupling agents can affect the curing strength of the polyurethane windshield glass adhesive, and the primer-free effect of the vehicle body paint can not be achieved without using tackifying resin. Patent CN00804626.3 discloses that no tackifier is used in the polymer, and the effect of no priming on the painted surface cannot be achieved. Patent CN104861918A discloses a one-component polyurethane sealant which is cured for a short time and does not swell, is mainly used for the application of short-term baking after surface painting, but also can not completely meet the primer-free adhesion of plastic substrates such as vehicle body paint, aluminum alloy, PA6/PBT/PP and the like.

Therefore, the polyurethane sealant which can realize primer-free adhesion to plastic substrates such as white glass, ink glass, vehicle body paint, aluminum alloy, PA/PBT/PP and the like is urgently needed.

Disclosure of Invention

The invention aims to provide a primer-free polyurethane sealant and a preparation method and application thereof. The primer-free polyurethane sealant provided by the invention can realize primer-free adhesion to plastic substrates such as white glass, ink glass, vehicle body paint, aluminum alloy, PA/PBT/PP and the like.

The invention provides a primer-free polyurethane sealant which is prepared from the following raw materials in percentage by mass:

preferably, the polyurethane polymer is polymerized from a polyether polyol and a first isocyanate.

Preferably, the first isocyanate includes one or two of an aromatic polyisocyanate, an aliphatic polyisocyanate, and an alicyclic polyisocyanate.

Preferably, the preparation method of the polyurethane polymer comprises: and mixing polyether polyol, first isocyanate and a first catalyst for polymerization reaction to obtain the polyurethane polymer.

Preferably, the first catalyst comprises stannous octoate or zinc isooctanoate.

Preferably, the temperature of the polymerization reaction is 60-80 ℃, and the time of the polymerization reaction is 2-6 h.

Preferably, after the polymerization reaction is completed, the product of the polymerization reaction is subjected to thin-film distillation to obtain the polyurethane polymer.

Preferably, the isocyanate comprises one or more of a TDI biuret, a TDI trimer, an IPDI biuret, an IPDI trimer, an HDI biuret, and an HDI trimer.

The invention also provides a preparation method of the primer-free polyurethane sealant, which comprises the following steps:

(1) mixing a polyurethane polymer, isocyanate, a plasticizer, a filler and carbon black under a vacuum condition to obtain a mixture;

(2) and (2) mixing the mixture obtained in the step (1) with a long carbon chain silane coupling agent, an acrylate monomer, a water absorbent, a tertiary amine catalyst and an organic tin catalyst to obtain the primer-free polyurethane sealant.

The invention also provides the application of the primer-free polyurethane sealant in the technical scheme or the primer-free polyurethane sealant prepared by the preparation method in the technical scheme.

The invention provides a primer-free polyurethane sealant which is prepared from the following raw materials in percentage by mass: 30-50% of polyurethane polymer, 0.5-2% of isocyanate, 10-30% of plasticizer, 10-30% of filler, 10-30% of carbon black, 0.2-0.5% of water absorbent, 0.2-0.5% of long carbon chain silane coupling agent, 0.2-2% of acrylate monomer, 0.01-0.1% of tertiary amine catalyst and 0.01-0.05% of organic tin catalyst. According to the invention, the polyurethane polymer and isocyanate are used as raw materials, and under the composite action of the tertiary amine catalyst and the organic tin catalyst, the primer-free adhesive property of the paint surface is improved; the long carbon chain silane coupling agent and the acrylate monomer are used together to improve the primer-free bonding performance of various plastic substrates such as glass, printing ink, aluminum alloy, PA/PBT/PP and the like. The results of the examples show that the primer-free polyurethane sealant provided by the invention has primer-free bonding performance for different types of substrates and high bonding strength.

Detailed Description

in the present invention, the starting materials are those conventionally commercially available in the art unless otherwise specified.

The raw materials for preparing the primer-free polyurethane sealant comprise, by mass, 30-50% of polyurethane polymer, preferably 35-45%, and more preferably 40%. In the invention, the polyurethane polymer is used as the main curing resin, so that the overall strength of the sealant is improved.

In the present invention, the polyurethane polymer is preferably obtained by polymerizing a polyether polyol and a first isocyanate.

In the present invention, the polyether polyol is preferably a polyether triol and/or a polyether diol. When the polyether polyol is polyether triol and polyether diol, the mass ratio of the polyether triol to the polyether diol is preferably 2: 1.

In the invention, the average molecular weight of the polyether triol is preferably 3000-6000, more preferably 5000-6000, and most preferably 6000; the hydroxyl value of the polyether triol is preferably 28-56 mgKOH/g, more preferably 28-33.6 mgKOH/g, and most preferably 28 mgKOH/g. In the invention, the average molecular weight of the polyether glycol is preferably 1000-4000, more preferably 2000-4000, and most preferably 4000; the hydroxyl value of the polyether diol is preferably 28-112 mgKOH/g, more preferably 28-56 mgKOH/g, and most preferably 28 mgKOH/g. The invention controls the average molecular weight and hydroxyl value of polyether polyol to make the prepared polyurethane polymer reach the balance of strength and flexibility in a certain molecular weight range.

In the present invention, the first isocyanate preferably includes one or two of aromatic polyisocyanate, aliphatic polyisocyanate and alicyclic polyisocyanate.

In the present invention, the aromatic polyisocyanate preferably includes TDI, MDI, 1, 4-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, Xylylene Diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), tolidine diisocyanate (TODI), 1, 5-Naphthalene Diisocyanate (NDI), or triphenylmethane triisocyanate; the TDI is preferably 2, 4-toluene diisocyanate (2,4-TDI) or 2, 6-toluene diisocyanate (2, 6-TDI); the MDI is preferably 4,4 '-diphenylmethane diisocyanate (4, 4' -MDI) or 2,4 '-diphenylmethane diisocyanate (2, 4' -MDI). In the present invention, the aliphatic polyisocyanate preferably includes Hexamethylene Diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate or norbornane diisocyanate (NBDI). In the present invention, the alicyclic polyisocyanate preferably includes trans-cyclohexane-1, 4-diisocyanate, isophorone diisocyanate (IPDI), bis (isocyanatomethyl) cyclohexane (H6XDI), or dicyclohexylmethane diisocyanate (H12 MDI). In an embodiment of the present invention, the first isocyanate is preferably 4,4 '-diphenylmethane diisocyanate, 2, 4' -diphenylmethane diisocyanate or xylylene diisocyanate. The present invention selects the above-mentioned isocyanates to react with the polyether to form the polyurethane polymer, further improving the colloidal strength.

In the present invention, the polyether polyol and the first isocyanate are preferably used in an NCO/OH ratio of (3-7): 1, more preferably (4-6): 1. The present invention makes it possible to obtain polyurethane polymers with a uniform molecular weight distribution, but not too much, by controlling the NCO/OH ratio to keep the NCO excess, which facilitates recycling.

In the invention, the mass content of NCO in the polyurethane polymer is preferably 1.8-3.0%.

In the present invention, the preparation method of the polyurethane polymer preferably includes: and mixing polyether polyol, first isocyanate and a first catalyst for polymerization reaction to obtain the polyurethane polymer.

In the present invention, the water content in the polyether polyol is preferably 100ppm or less. In the present invention, when the water content in the polyether polyol does not satisfy the above conditions, the present invention preferably subjects the polyether polyol to vacuum dehydration before use; the temperature of the vacuum dehydration is preferably 110-130 ℃, and more preferably 120 ℃; the time of the vacuum dehydration is preferably 2-4 h, and more preferably 3 h. In the present invention, the vacuum dehydration is preferably performed while stirring. The vacuum degree of the vacuum dehydration and the stirring rate are not particularly limited in the present invention, and the operation well known to those skilled in the art can be adopted.

In the present invention, the first catalyst preferably includes stannous octoate or zinc isooctanoate. The catalyst can promote the synthesis of polyurethane polymer.

The operation of mixing the polyether polyol, the first isocyanate and the first catalyst is not particularly limited in the present invention, and the technical scheme of mixing materials, which is well known to those skilled in the art, can be adopted.

In the invention, the polymerization reaction temperature is preferably 60-80 ℃, more preferably 65-75 ℃, and finally 70 ℃; the time of the polymerization reaction is preferably 2 to 6 hours, more preferably 3 to 5 hours, and most preferably 4 hours. The invention can control the complete progress of the polyurethane polymerization reaction by controlling the temperature and the time of the polymerization reaction.

After the polymerization reaction is completed, the present invention preferably thin-film distills the product of the polymerization reaction to obtain the polyurethane polymer. In the present invention, the thin film distillation is capable of removing unreacted free first isocyanate monomer.

The polyurethane polymer prepared by the thin film distillation method has the characteristics of uniform average molecular weight distribution, low viscosity, low free isocyanate content and no bubbling in the high-temperature curing process.

The raw materials for preparing the primer-free polyurethane sealant provided by the invention further comprise 0.5-2% by mass of isocyanate, and preferably 1-1.5% by mass of isocyanate.

In the present invention, the isocyanate preferably includes one or more of TDI biuret, TDI trimer, IPDI biuret, IPDI trimer, HDI biuret, and HDI trimer. The isocyanate is selected to improve the bonding performance of the polyurethane sealant on the paint surface.

The raw materials for preparing the primer-free polyurethane sealant provided by the invention further comprise 10-30% of a plasticizer, preferably 15-25%, and more preferably 20% by mass.

In the present invention, the plasticizer is preferably one or two of alkyl sulfonate, diisooctyl phthalate (DIOP), diisodecyl phthalate (DIDP), diisononyl phthalate (DINP), diisodecyl cyclohexanedicarboxylate (DIDCH), diisononyl cyclohexanedicarboxylate (DINCH), tricresyl phosphate and trioctyl phosphate, and more preferably one or two of diisodecyl phthalate (DIDP) and diisononyl phthalate (DINP). The invention can increase the fluidity of the polyurethane adhesive by selecting the function of the plasticizer.

The raw materials for preparing the primer-free polyurethane sealant provided by the invention further comprise 10-30% of filler, preferably 15-25%, and more preferably 20% by mass.

In the present invention, the filler is preferably one of ground silica, ground calcium carbonate, talc, clay, organobentonite, hydrogenated castor oil, and barium sulfate.

The raw materials for preparing the primer-free polyurethane sealant provided by the invention also comprise 10-30% of carbon black, 15-25% of carbon black, and more preferably 20% of carbon black.

In the present invention, the carbon black is preferably one of gas furnace carbon black, oil gas furnace carbon black, thermal carbon black and acetylene black. The strength of the polyurethane adhesive can be further improved by selecting the carbon black.

The raw materials for preparing the primer-free polyurethane sealant provided by the invention also comprise 0.2-0.5% of water absorbent, preferably 0.3-0.4% by mass.

In the present invention, the water absorbent is preferably one of calcium oxide, molecular sieve, TI water absorbent, and more preferably TI water absorbent. The water absorbent is selected to improve the storage property of the polyurethane adhesive.

The raw materials for preparing the primer-free polyurethane sealant also comprise, by mass, 0.2-0.5% of a long-carbon-chain silane coupling agent, and preferably 0.3-0.4%.

In the present invention, the long carbon chain silane coupling agent is preferably one of gamma-glycidoxy octyltrimethoxysilane, gamma-mercaptooctyltrimethoxysilane, and gamma-acryloyloxy octyltrimethoxysilane. The silane coupling agent is selected, so that the adhesion of the polyurethane adhesive on white glass, printing ink and low-surface-energy base materials can be further improved.

The raw materials for preparing the primer-free polyurethane sealant provided by the invention further comprise 0.2-2% of acrylate monomer, preferably 0.5-1.5%, and more preferably 1% by mass.

In the present invention, the acrylate monomer is preferably one of methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, lauryl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, trimethylolpropane trimethacrylate, more preferably trimethylolpropane trimethacrylate. The invention selects the acrylate monomer to further improve the adhesion of the polyurethane adhesive on the low surface energy base material.

The raw materials for preparing the primer-free polyurethane sealant also comprise 0.01-0.1% of tertiary amine catalyst, preferably 0.04-0.08% by mass.

In the present invention, the tertiary amine catalyst is preferably one of N, N-dimethylcyclohexylamine, bis (2-dimethylaminoethyl) ether, dimorpholinodiethyl ether, N' -tetramethylalkylenediamine, triethylamine and N, N-dimethylbenzylamine, and more preferably dimorpholinodiethyl ether or triethylamine. The catalyst selected by the invention can promote the curing of the polyurethane sealant in use.

The raw materials for preparing the primer-free polyurethane sealant also comprise 0.01-0.05% of organic tin catalyst, preferably 0.02-0.04% by mass.

In the present invention, the organotin-based catalyst is preferably dioctyltin dilaurate, dibutyltin dilaurate, dimethyltin dilaurate, stannous octoate, butyltin oxide, octyltin oxide, dialkyltin mercaptide or dialkyltin mercaptide, and more preferably dialkyltin mercaptide or dialkyltin mercaptide. The catalyst selected by the invention can promote the curing of the polyurethane sealant in use.

According to the invention, the polyurethane polymer and isocyanate are used as raw materials, and under the composite action of the tertiary amine catalyst and the organic tin catalyst, the primer-free adhesive property of the paint surface is improved; the long carbon chain silane coupling agent and the acrylate monomer are used together to improve the primer-free bonding performance of various plastic substrates such as glass, printing ink, aluminum alloy, PA/PBT/PP and the like.

According to the invention, the polyurethane polymer, the isocyanate, the plasticizer, the filler and the carbon black are mixed under a vacuum condition to obtain a mixture.

In the present invention, the plasticizer is preferably vacuum dehydrated before use; the temperature of the vacuum dehydration is preferably 110-130 ℃, more preferably 115-125 ℃, and most preferably 120 ℃; the time of the vacuum dehydration is preferably 1.5-2.5 h, and more preferably 2 h.

In the present invention, the water content in the filler and carbon black is preferably 300ppm or less. In the present invention, when the water content in the filler and carbon black does not satisfy the above conditions, the present invention preferably vacuum-dries the filler and carbon black; the temperature of the vacuum drying is preferably 115-125 ℃, and more preferably 120 ℃; the time for vacuum drying is preferably 3 to 7 days, and more preferably 4 to 6 days.

In the present invention, the degree of vacuum under vacuum at the time of mixing is preferably not less than 980 mbar. The operation of the mixing is not particularly limited in the present invention, and the technical scheme of material mixing known to those skilled in the art can be adopted.

After the mixture is obtained, the mixture is mixed with a long carbon chain silane coupling agent, an acrylate monomer, a water absorbent, a tertiary amine catalyst and an organic tin catalyst to obtain the primer-free polyurethane sealant.

In the present invention, the mixing of the mixture with the long carbon chain silane coupling agent, the acrylate monomer, the water absorbing agent, the tertiary amine catalyst and the organotin catalyst is preferably performed under stirring conditions; the stirring temperature is preferably below 60 ℃; the stirring time is preferably 30-60 min.

The invention also provides the application of the primer-free polyurethane sealant prepared by the technical scheme or the primer-free polyurethane sealant prepared by the preparation method of the technical scheme in primer-free coating of various plastic substrates such as glass, printing ink, aluminum alloy, PA/PBT/PP and the like. The operation of the application is not particularly limited by the invention, and the application mode of the bottomless gluing which is well known to the technical personnel in the field can be adopted.

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The primer-free polyurethane sealant in the embodiment is prepared from the following raw materials in percentage by mass: 30% of polyurethane polymer, 0.5% of isocyanate, 20% of plasticizer, 23.88% of filler, 25% of carbon black, 0.2% of water absorbent, 0.2% of long-carbon-chain silane coupling agent, 0.2% of acrylate monomer, 0.01% of tertiary amine catalyst and 0.01% of organic tin catalyst.

Wherein the polyurethane polymer is polyurethane polymer A1 and is obtained by polymerizing polyether polyol and first isocyanate; the polyether polyol is polyether triol (with an average molecular weight of 5000) and polyether diol (with an average molecular weight of 2000), and the mass ratio of the polyether triol to the polyether diol is 2: 1; the first isocyanate is 4,4 '-diisocyanatophenylmethane (4, 4' -MDI); the NCO/OH of the polyether polyol and the first isocyanate is 4.

The preparation method of the polyurethane polymer A1 comprises the following steps: heating polyether polyol (1000 g of polyether triol and 500g of polyether diol) to 120 ℃, carrying out vacuum dehydration for 3 hours, then cooling to 50 ℃, adding 550g of 4,4 '-diisocyanate phenyl methane (4, 4' -MDI) (NCO/OH is 4 at the moment) and 0.15g of stannous octoate, mixing, and heating to 80 ℃ for polymerization reaction for 4 hours; the unreacted free first isocyanate monomer was removed by thin film distillation to give polyurethane polymer a1 having an NCO% content of 2.63%.

Isocyanate is MDI, plasticizer is DINP, filler is coarse whiting, carbon black is oil furnace carbon black, water absorbent is calcium oxide, long carbon chain silane coupling agent is gamma-glycidyl ether oxyoctyl trimethoxy silane, acrylate monomer is trimethylolpropane trimethacrylate, tertiary amine catalyst is dimorpholine diethyl ether, and organic tin catalyst is dialkyl tin mercaptide.

The preparation method of the primer-free polyurethane sealant in the embodiment comprises the following steps:

(1) mixing a polyurethane polymer, isocyanate, a plasticizer, a filler and carbon black under a vacuum condition to obtain a mixture; the vacuum degree is not lower than 980 mbar;

before the plasticizer is used, the vacuum dehydration is carried out for 2h at 120 ℃, and the filler and the carbon black are dried in a vacuum oven at 120 ℃ for 3 days to ensure that the moisture content of the filler and the carbon black is below 300 ppm;

(2) and (2) mixing the mixture obtained in the step (1) with a long carbon chain silane coupling agent, an acrylate monomer, a water absorbent, a tertiary amine catalyst and an organic tin catalyst at the temperature of below 60 ℃ under vacuum stirring for 30min to obtain the primer-free polyurethane sealant.

Example 2

The primer-free polyurethane sealant in the embodiment is prepared from the following raw materials in percentage by mass: 30% of polyurethane polymer, 1% of isocyanate, 20% of plasticizer, 22.65% of filler, 25% of carbon black, 0.2% of water absorbent, 0.5% of long-carbon-chain silane coupling agent, 0.5% of acrylate monomer, 0.1% of tertiary amine catalyst and 0.05% of organic tin catalyst.

The kind and source of each raw material were the same as those in example 1.

The preparation method of the primer-free polyurethane sealant in the embodiment is the same as that of the embodiment 1.

Example 3

The primer-free polyurethane sealant in the embodiment is prepared from the following raw materials in percentage by mass: 40% of polyurethane polymer, 1% of isocyanate, 20% of plasticizer, 18.03% of filler, 20% of carbon black, 0.2% of water absorbent, 0.2% of long-carbon-chain silane coupling agent, 0.5% of acrylate monomer, 0.05% of tertiary amine catalyst and 0.02% of organic tin catalyst.

The kind and source of each raw material were the same as those in example 1.

Example 4

The primer-free polyurethane sealant in the embodiment is prepared from the following raw materials in percentage by mass: 40% of polyurethane polymer, 2% of isocyanate, 20% of plasticizer, 16.16% of filler, 20% of carbon black, 0.2% of water absorbent, 0.5% of long-carbon-chain silane coupling agent, 1% of acrylate monomer, 0.1% of tertiary amine catalyst and 0.04% of organic tin catalyst.

The kind and source of each raw material were the same as those in example 1.

Example 5

The primer-free polyurethane sealant in the embodiment is prepared from the following raw materials in percentage by mass: 50% of polyurethane polymer, 0.5% of isocyanate, 15% of plasticizer, 10% of filler, 22.43% of carbon black, 0.5% of water absorbent, 0.5% of long-carbon-chain silane coupling agent, 1% of acrylate monomer, 0.05% of tertiary amine catalyst and 0.02% of organic tin catalyst.

The kind and source of each raw material were the same as those in example 1.

Example 6

The primer-free polyurethane sealant in the embodiment is prepared from the following raw materials in percentage by mass: 50% of polyurethane polymer, 2% of isocyanate, 15% of plasticizer, 10% of filler, 19.85% of carbon black, 0.5% of water absorbent, 0.5% of long-carbon-chain silane coupling agent, 2% of acrylate monomer, 0.1% of tertiary amine catalyst and 0.05% of organic tin catalyst.

The kind and source of each raw material were the same as those in example 1.

Example 7

Except for the type and source of the polyurethane polymer, the raw materials, the proportion and the preparation method of the primer-free polyurethane sealant in the embodiment are the same as those in the embodiment 1.

The polyurethane polymer in the raw materials of this example is polyurethane polymer a2, and is obtained by polymerizing polyether polyol and first isocyanate; the polyether polyol is polyether triol, and the average molecular weight is 6000; the first isocyanate is 4,4 '-diisocyanatophenylmethane (4, 4' -MDI); the NCO/OH of the polyether polyol and the first isocyanate is 6.

The preparation method of the polyurethane polymer A2 comprises the following steps: heating 1500g of polyether polyol to 120 ℃, dehydrating in vacuum for 3h, then cooling to 50 ℃, adding 563g of 4,4 '-diisocyanate phenyl methane (4, 4' -MDI) (NCO/OH is 6) and 0.12g of zinc isooctanoate, mixing, and heating to 60 ℃ for polymerization for 6 h; the unreacted free first isocyanate monomer was removed by thin film distillation to give polyurethane polymer a2 having an NCO% content of 1.90%.

Example 8

The raw materials, the proportion and the preparation method of the primer-free polyurethane sealant in the embodiment are the same as those in the embodiment 2, and the only difference is that the polyurethane polymer in the raw materials is a polyurethane polymer A2.

Example 9

The raw materials, the proportion and the preparation method of the primer-free polyurethane sealant in the embodiment are the same as those in the embodiment 3, and the only difference is that the polyurethane polymer in the raw materials is a polyurethane polymer A2.

Example 10

The raw materials, the proportion and the preparation method of the primer-free polyurethane sealant in the embodiment are the same as those in the embodiment 4, and the only difference is that the polyurethane polymer in the raw materials is a polyurethane polymer A2.

Example 11

The raw materials, the proportion and the preparation method of the primer-free polyurethane sealant in the embodiment are the same as those in the embodiment 5, and the only difference is that the polyurethane polymer in the raw materials is a polyurethane polymer A2.

Example 12

The raw materials, the proportion and the preparation method of the primer-free polyurethane sealant in the embodiment are the same as those in the embodiment 6, and the only difference is that the polyurethane polymer in the raw materials is a polyurethane polymer A2.

Comparative example 1

The primer-free polyurethane sealant in the comparative example is prepared from the following raw materials in percentage by mass: 40% of polyurethane polymer, 20% of plasticizer, 18.03% of filler, 20.7% of carbon black, 0.2% of water absorbent, 0.5% of long-carbon-chain silane coupling agent, 0.5% of acrylate monomer, 0.05% of tertiary amine catalyst and 0.02% of organic tin catalyst. (isocyanate-free)

The kinds and sources of the respective raw materials listed in this comparative example were the same as those of example 1.

The preparation method of the primer-free polyurethane sealant in the comparative example is the same as that of the example 1.

Comparative example 2

The primer-free polyurethane sealant in the comparative example is prepared from the following raw materials in percentage by mass: 40% of polyurethane polymer, 1% of isocyanate, 20% of plasticizer, 18.03% of filler, 19.72% of carbon black, 0.2% of water absorbent, 0.5% of long-carbon-chain silane coupling agent, 0.5% of acrylate monomer and 0.05% of tertiary amine catalyst. (containing no organotin catalysts)

Comparative example 3

The primer-free polyurethane sealant in the comparative example is prepared from the following raw materials in percentage by mass: 40% of polyurethane polymer, 1% of isocyanate, 20% of plasticizer, 18.03% of filler, 20.2% of carbon black, 0.2% of water absorbent, 0.5% of acrylate monomer, 0.05% of tertiary amine catalyst and 0.02% of organic tin catalyst. (not containing a long carbon chain silane coupling agent)

Comparative example 4

The primer-free polyurethane sealant in the comparative example is prepared from the following raw materials in percentage by mass: 40% of polyurethane polymer, 1% of isocyanate, 20% of plasticizer, 18.03% of filler, 20.2% of carbon black, 0.2% of water absorbent, 0.5% of long-carbon-chain silane coupling agent, 0.05% of tertiary amine catalyst and 0.02% of organic tin catalyst. (free of acrylate monomers)

Comparative example 5

The primer-free polyurethane sealant in the comparative example is prepared from the following raw materials in percentage by mass: 40% of polyurethane polymer, 1% of isocyanate, 20% of plasticizer, 18.03% of filler, 20.2% of carbon black, 0.2% of water absorbent, 0.5% of KH-560 coupling agent, 0.05% of tertiary amine catalyst and 0.02% of organic tin catalyst. (free of acrylate monomers)

The kinds and sources of the raw materials listed in this comparative example were the same as those in example 1.

The primer-free polyurethane sealants prepared in examples 1 to 12 and comparative examples 1 to 5 are respectively subjected to performance tests, surface drying time, tensile strength, elongation at break and substrate adhesion test methods, and the tests are carried out by referring to relevant standards in HG/T4363-.

The test results are shown in tables 1 and 2, respectively.

TABLE 1 mechanical properties of the primer-free polyurethane sealants of examples 1-12 and comparative examples 1-5

TABLE 2 adhesion Properties of primer-free polyurethane sealants of examples 1 to 12 and comparative examples 1 to 5

Note: PP is plasma flame treated and CF is cohesive failure

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. The primer-free polyurethane sealant is prepared from the following raw materials in percentage by mass:

2. the primer-free polyurethane sealant according to claim 1, wherein the polyurethane polymer is obtained by polymerizing a polyether polyol and a first isocyanate.

3. The primer-free polyurethane sealant according to claim 2, wherein the first isocyanate comprises one or two of an aromatic polyisocyanate, an aliphatic polyisocyanate and an alicyclic polyisocyanate.

4. The primer-free polyurethane sealant according to claim 2 or 3, wherein the preparation method of the polyurethane polymer comprises the following steps: and mixing polyether polyol, first isocyanate and a first catalyst for polymerization reaction to obtain the polyurethane polymer.

5. The primer-free polyurethane sealant according to claim 4, wherein the first catalyst comprises stannous octoate or zinc isooctanoate.

6. The primer-free polyurethane sealant as claimed in claim 4, wherein the temperature of the polymerization reaction is 60-80 ℃, and the time of the polymerization reaction is 2-6 h.

7. The primer-free polyurethane sealant according to claim 4, wherein after the polymerization reaction is completed, the product of the polymerization reaction is subjected to thin-film distillation to obtain the polyurethane polymer.

8. The primer-free polyurethane sealant according to claim 1, wherein the isocyanate comprises one or more of TDI biuret, TDI trimer, IPDI biuret, IPDI trimer, HDI biuret, and HDI trimer.

9. The preparation method of the primer-free polyurethane sealant as claimed in any one of claims 1 to 8, which comprises the following steps:

10. The use of the primer-free polyurethane sealant according to any one of claims 1 to 8 or the primer-free polyurethane sealant prepared by the preparation method according to claim 9.