CN114763402B - Heat-resistant polyurethane foam and preparation method thereof - Google Patents

Heat-resistant polyurethane foam and preparation method thereof Download PDF

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CN114763402B
CN114763402B CN202110046175.6A CN202110046175A CN114763402B CN 114763402 B CN114763402 B CN 114763402B CN 202110046175 A CN202110046175 A CN 202110046175A CN 114763402 B CN114763402 B CN 114763402B
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polyol
content
polyurethane foam
glycol
foam according
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CN114763402A (en
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张思思
何国龙
郑小生
李泽民
沈沉
魏鹏
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Wanhua Chemical Beijing Co Ltd
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Wanhua Chemical Beijing Co Ltd
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    • 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
    • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
    • C08G18/66—Compounds of groups C08G18/42, C08G18/48, or C08G18/52
    • C08G18/6603—Compounds of groups C08G18/42, C08G18/48, or C08G18/52 with compounds of group C08G18/32 or polyamines of C08G18/38
    • C08G18/6607—Compounds of groups C08G18/42, C08G18/48, or C08G18/52 with compounds of group C08G18/32 or polyamines of C08G18/38 with compounds of group C08G18/3203
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    • C08G18/30—Low-molecular-weight compounds
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    • C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
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    • C08G18/4009—Two or more macromolecular compounds not provided for in one single group of groups C08G18/42 - C08G18/64
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    • C08G18/40—High-molecular-weight compounds
    • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
    • C08G18/4266—Polycondensates having carboxylic or carbonic ester groups in the main chain prepared from hydroxycarboxylic acids and/or lactones
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    • C08G18/48—Polyethers
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    • C08G18/40—High-molecular-weight compounds
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    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
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    • C08G18/40—High-molecular-weight compounds
    • C08G18/63—Block or graft polymers obtained by polymerising compounds having carbon-to-carbon double bonds on to polymers
    • C08G18/632—Block or graft polymers obtained by polymerising compounds having carbon-to-carbon double bonds on to polymers onto polyethers
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    • 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
    • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
    • C08G18/66—Compounds of groups C08G18/42, C08G18/48, or C08G18/52
    • C08G18/6603—Compounds of groups C08G18/42, C08G18/48, or C08G18/52 with compounds of group C08G18/32 or polyamines of C08G18/38
    • C08G18/6614—Compounds of groups C08G18/42, C08G18/48, or C08G18/52 with compounds of group C08G18/32 or polyamines of C08G18/38 with compounds of group C08G18/3225 or C08G18/3271 and/or polyamines of C08G18/38
    • C08G18/6618—Compounds of groups C08G18/42, C08G18/48, or C08G18/52 with compounds of group C08G18/32 or polyamines of C08G18/38 with compounds of group C08G18/3225 or C08G18/3271 and/or polyamines of C08G18/38 with compounds of group C08G18/3225 or polyamines of C08G18/38
    • C—CHEMISTRY; METALLURGY
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    • C08G2101/00—Manufacture of cellular products

Abstract

The invention provides a heat-resistant polyurethane foam which is mainly applied to polyurethane products such as self-skinning engine covers, oil rail cladding parts and the like. Aiming at the defect of insufficient heat resistance of products in the prior art, polytetramethylene glycol, polycaprolactone polyol and a polyol-containing polyurethane cross-linking agent are introduced and are matched with other components such as polyether polyol, polymer polyol and the like for use, so that the heat resistance of the foam can be greatly improved, and meanwhile, the foam has excellent skinning performance, good silencing performance and excellent mechanical property. The invention also provides a preparation method of the foam.

Description

Heat-resistant polyurethane foam and preparation method thereof
Technical Field
The invention relates to a heat-resistant polyurethane foam, in particular to a self-skinning polyurethane foam with good heat resistance, good noise reduction and excellent mechanical property, and a preparation method of the polyurethane foam, which can meet the special performance requirements of products such as an automobile engine cover, an oil rail cladding and the like.
Background
Polyurethane foam is widely used in the fields of household, automobiles, shoe materials and the like. Self-skinning polyurethane foams (ISFs) were first developed successfully by shell companies. The self-skinning technology adopts integral molding, simplifies the secondary or multiple molding technology of firstly preparing foam and then cladding by leather or fabric and the like, and the obtained foam product has soft inner core and compact epidermis and excellent foam performance. The self-skinning products are widely applied to the fields of automobile steering wheels, instrument panels, armrests, bicycle and motorcycle cushions, bumpers and the like at present, but few researches report that the self-skinning products are applied to engine cover products. In order to meet the application requirements of engine hoods, the self-skinning product needs to have good heat resistance and acoustic performance besides good molding appearance and high mechanical strength.
At present, most of polyurethane foams applied to engine hoods are light foams or soft foams, the density of the foams is low, the strength is poor, the requirements on performance of appearance parts cannot be met when the polyurethane foams are singly used, the polyurethane foams are used for compounding with other materials, and the physical properties and the sound absorption properties of the materials are not clearly defined.
Patent CN200710196390.4 discloses a polyurethane foam for vehicles and a process for producing the same, the resultant product having a density of 20kg/m or less 3 The light foam of (2) is used as an interior material for engine silencers and instrument panel silencers, can not meet the requirement of directly serving as a finished product of an engine hood, needs to be compounded with other products, has the problem of secondary processing or multiple processing, and has no investigation on mechanical properties before and after heat resistance, and the important investigation is flame retardant property.
Patent CN201180055679.9 discloses a soft polyurethane foam under the hood for sound insulation and vibration control. The product obtained in the invention is a soft foam non-self-skinning product, can not be independently used for preparing a finished product of an engine hood, has the problems of secondary processing and composite use with other products, has soft density of 80-140kg/m < 3 >, has tensile strength of 150kPa, has lower physical strength, and can not meet the higher physical requirement of an appearance part; in addition, the heat resistance of the foam is not examined in this patent.
Therefore, it is necessary to provide a self-skinning polyurethane foam with good heat resistance, good noise reduction and excellent mechanical properties so as to meet the technical requirements of products of polyurethane in the application fields of automobile engine covers, oil rail cladding and the like.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides self-skinning polyurethane foam with good heat resistance, good noise reduction and excellent mechanical properties, and a preparation method of the polyurethane foam.
In order to achieve the above purpose, the following technical scheme is adopted:
a self-skinning polyurethane foam obtained from the reaction of an isocyanate-reactive component comprising a mixed polyol, a crosslinker, a blowing agent, a catalyst, a chain extender, and a B isocyanate component;
wherein the mixed polyol comprises polytetramethylene ether glycol A1 and polyester polyol A2;
the hydroxyl value of the polytetramethylene ether glycol A1 is 28-224 mgKOH/g, preferably 56-112 mgKOH/g;
the polytetramethylene ether glycol is also called polytetrahydrofuran, the functionality is 2, the main chain of the polytetramethylene ether glycol is a linear structure composed of a carbon chain and ether bonds, unsaturated bonds are not contained, the flexibility is good, the polytetramethylene ether glycol A1 and the polyester polyol A2 are mixed for use, and the prepared self-skinning polyurethane foam has good ageing resistance and mechanical properties.
The polyester polyol A2 may be a conventional polyester polyol, for example, a polyester polyol obtained by polymerizing a polyol and a polybasic acid, a polyester polyol obtained by polymerizing an acid anhydride and a polyol, a polyester polyol obtained by ring-opening polymerization of a lactone with a polyol as an initiator, or the like, and such polyester polyols may be used alone or in combination;
as a preferred technical scheme of the present invention, the polyester polyol A2 is: polyester polyol obtained by ring-opening polymerization of lactone with polyol as initiator, and having a hydroxyl value of 22-336 mgKOH/g, preferably 28-168 mgKOH/g; wherein the functionality of the initiator for synthesizing the polyester polyol A2 is 2-4;
when the polyester polyol A2 is a polyester polyol obtained by ring-opening polymerization of a lactone using a polyol as a starter, suitable starter include, but are not limited to, ethylene glycol, propylene glycol, butylene glycol, pentylene glycol, hexylene glycol, heptylene glycol, octylene glycol, decylene glycol, glycerol, trimethylolpropane, pentaerythritol, neopentyl glycol, etc., and such starter may be used alone or in combination; suitable lactones include, but are not limited to, propiolactone, butyrolactone, valerolactone, caprolactone, etc., which may be used alone or in combination;
as a further preferred embodiment, the hydroxyl value of the polyester polyol A2 is 28 to 224mgKOH/g, preferably 56 to 112mgKOH/g, the initiator for the synthesis of the polyester polyol A2 is neopentyl glycol and the lactone is epsilon-caprolactone. The use of the polyester polyol A2 can effectively improve the mechanical properties of the polyurethane product.
As a preferred technical scheme of the invention, the mixed polyol further comprises polyether polyol A3, and is polymerized by an initiator and propylene oxide and/or ethylene oxide;
the polyether polyol A3 may be selected from conventional polyether polyols, examples of which include, but are not limited to, polyether polyols having a functionality of 2 to 8 and a hydroxyl value of 24 to 240mgKOH/g; among them, the initiator used for the synthesis of the polyether polyol is a compound containing an active hydrogen atom, examples of which include, but are not limited to, polyols, polyamines, polyalcohol amines and the like, more specifically, ethylene glycol, propylene glycol, glycerol, trimethylolpropane, propionic acid alcohol, mannitol, sorbitol, pentaerythritol, sucrose, xylitol, ethylenediamine, triethanolamine, toluenediamine and the like, and such initiators may be used alone or in combination;
as a further preferred embodiment, the polyether polyol A3 has a functionality of 3 and a hydroxyl number of 28 to 35mgKOH/g. The use of the high molecular weight polyether polyol is more beneficial to providing a flexible chain segment for polyurethane, balancing the hardness of the product and improving the elongation at break.
As a preferred embodiment of the present invention, the mixed polyol further comprises a polymer polyol A4 having a functionality of 2 to 3, a hydroxyl value of 18 to 30mgKOH/g, preferably 21 to 24mgKOH/g, and a solids content of 15 to 45% by weight, preferably 20 to 40% by weight. The use of the polymer polyol can more effectively improve the hardness of polyurethane, and is beneficial to improving the tensile strength and the tearing strength of foam;
suitable polymer polyols A4 refer to polyether polyols modified with vinyl monomers, examples of which include, but are not limited to, acrylonitrile, styrene, methyl methacrylate, vinyl acetate, vinyl chloride, and the like, which may be used alone or in combination. Preferably, the vinyl monomer used for synthesizing the polymer polyol A4 is acrylonitrile and/or styrene.
As a preferable technical scheme of the invention, the cross-linking agent is an amino cross-linking agent with 3-functionality and a plurality of ester groups, and the molecular structure is as follows:
wherein X is selected from aliphatic linking groups with a linear structure, aliphatic linking groups with a cyclic structure, aromatic linking groups, aliphatic linking groups with hetero atoms, preferably aliphatic linking groups with a cyclic structure, or aromatic linking groups; r is an organic group inert to isocyanate groups, preferably a saturated aliphatic group, more preferably a saturated aliphatic linking group having a linear structure and having 2 to 4 carbon atoms, such as ethyl;
in a preferred example, the X is selected from aliphatic linking groups having a cyclic structure, wherein the cyclic structure is a carbocyclic ring structure well known in the art, such as a cyclic structure having 5 to 12 carbon atoms, a bicyclic structure, a polycyclic structure, and the like, specifically exemplified by: cyclopentane, cyclohexane, methylcyclohexane, and the like.
In a preferred example, the X is selected from an aromatic linking group, and refers to a group having a benzene ring structure in the group, for example, a cyclic structure having 6 to 20 carbon atoms, a bicyclic structure, a polycyclic structure, and the like, specifically exemplified by: benzene, toluene, ethylbenzene, diphenylmethane, etc.
The crosslinking agent is particularly suitable for preparing polyurethane foam, and when used for polyurethane foam, the crosslinking agent can improve the physical properties (tensile strength, tearing strength and the like) of the foam and can also improve the thermal stability of the foam.
The cross-linking agent comprises the following preparation raw materials: a compound containing three primary amine groups, an ester compound containing one unsaturated double bond and optionally a catalyst;
the preparation method comprises the following steps:
step one, adding a compound containing three primary amine groups into a reactor, starting stirring, and optionally adding a catalyst;
step two, controlling the temperature of the reactor to be between 30 and 135 ℃, preferably between 60 and 95 ℃, adding an ester compound containing one unsaturated double bond into the reactor for reaction, and discharging after the reaction is finished;
in the preparation method, the molar ratio of the compound containing three primary amino groups to the ester compound containing one unsaturated double bond is preferably 1: 2.9-1:3.1;
in the second step, the method of adding the reactant to the reactor is well known in the art, for example, a slow dripping method, a batch method, a one-time method or the like can be adopted, the implementation of the present invention is not affected, and the preparation method preferably adopts slow dripping or batch adding of the reactant;
in the preparation method of the cross-linking agent, inert gas can be selectively introduced or not introduced in the reaction process, so that the implementation of the invention is not influenced. Whether the appearance of the reaction product is influenced by the introduction of inert gas or not is that the appearance of the reaction product which is introduced with the inert gas is colorless and transparent, and the appearance of the reaction product which is not introduced with the inert gas is light yellow. The preparation method of the invention preferably adopts the method of introducing inert gas;
in the preparation method of the cross-linking agent, the compound containing three primary amino groups has the structure of X- (NH) 2 ) 3 Wherein X is the structure X in the amino cross-linking agent with 3 functionality and a plurality of ester groups, and the compound containing three primary amino groups comprises, but is not limited to, trimellitic amine, 1,3, 5-triaminohexane, 1,3, 5-cyclohexane triamine, 1,3, 5-triaminobenzene, polyether amine and the like, and the compounds can be used singly or in combination. Preferably, the compound containing three primary amine groups is selected from 1,3, 5-cyclohexane triamine or 1,3, 5-triaminobenzene;
the compound containing three primary amine groups comprises the following beneficial effects as raw materials: the three primary amine groups react with unsaturated groups to form secondary amine groups, the formed secondary amine groups react with organic isocyanate as reactive groups to provide a better crosslinking effect, and meanwhile, the urea bond formed by the reaction of the secondary amine groups and the organic isocyanate can endow the foam with good physical properties. The strength of urea bond is larger than that of urethane bond, and the thermal stability is higher;
in the preparation method of the cross-linking agent, the ester compound containing one unsaturated double bond has the following structureStructure wherein R represents an organic group inert to isocyanate groups, preferably a saturated aliphatic group, more preferably ethyl. Examples of the ester compound having one unsaturated double bond include, but are not limited to, a maleic acid diester compound, a fumaric acid diester compound, etc., which may be used alone or in combination;
the maleic acid diester compound refers to a compound having a maleic acid structure and two ester group structures in the molecule, and examples which may be cited include, but are not limited to, dimethyl maleate, diethyl maleate, dibutyl maleate, diisobutyl maleate, dioctyl maleate, diisooctyl maleate, etc., such maleic acid diester compounds may be used alone or in combination;
the fumaric acid diester compound refers to a compound having a fumaric structure and two ester group structures in the molecule, and examples which may be cited include, but are not limited to, dimethyl fumarate, diethyl fumarate, dibutyl fumarate, diisobutyl fumarate, dioctyl fumarate, diisooctyl fumarate, etc., and such fumaric acid diester compounds may be used alone or in combination;
further preferably, the ester compound containing one unsaturated double bond is selected from diethyl maleate and/or diethyl fumarate;
the ester compound containing one unsaturated double bond as a raw material has the following beneficial effects: unsaturated double bonds react with primary amine with higher reactivity to form secondary amine with proper reactivity, so that a more proper crosslinking effect is provided for the system; the steric hindrance effect provided by the ester bond in the structure further reduces the reactivity of the secondary amine, and the existence of the ester bond is beneficial to improving the performance of the prepared product;
in the preparation method of the crosslinking agent, the catalyst may be selected from catalysts commonly used in the art, examples of which include, but are not limited to, basic organic compounds, basic inorganic compounds, etc., and more specific examples include, but are not limited to, sodium ethoxide, potassium tert-butoxide, potassium ethoxide, sodium tert-butoxide, methyl potassium, methyl sodium, butyl lithium, butyl potassium, triethyl aluminum, etc., and such catalysts may be used alone or in combination;
the amine value of the crosslinking agent is 120 to 310mgKOH/g, preferably 240 to 280mgKOH/g;
the above-mentioned crosslinking agent may be used alone or optionally in combination with a conventional crosslinking agent, which includes but is not limited to a small molecular polyol, a small molecular polyamine, a small molecular alcohol amine-based compound, more specific examples include but are not limited to glycerol, trimethylolpropane, trimethylolethane, pentaerythritol, diethanolamine, triethanolamine, triisopropanolamine, methyldiethanolamine, bis-2- (hydroxypropyl) aniline, and the like.
In the polyurethane foam of the present invention, the blowing agent may be a physical blowing agent and/or a chemical blowing agent commonly used in the art, examples of which include, but are not limited to, chlorofluorocarbon blowing agents, aliphatic hydrocarbons, water and the like, examples of chlorofluorocarbons include, but are not limited to, fluorotrichloromethane, 1-difluoroethane, 1, 2-tetrafluoroethane, 1, 3-pentafluorobutane, 1, 3-pentafluoropropane 1, 1-dichloro-1-fluoroethane, trans-1-chloro-3, 3-trifluoropropene, cis-1, 3-hexafluoro-2-butene, trans-1, 3-tetrafluoropropene, methylene chloride, etc., examples of aliphatic hydrocarbons include, but are not limited to, n-pentane, cyclopentane, isopentane, propiutane, and the like, and other examples of blowing agents that may be mentioned include methyl formate, diacetal, dimethyl ether, and the like, such physical blowing agents and/or chemical blowing agents may be used alone or in combination. In a preferred embodiment of the invention, the foaming agent is selected from water and/or cyclopentane.
In the polyurethane foam of the present invention, the catalyst may be selected from commonly used catalysts, examples of which include, but are not limited to, amine-type catalysts, organometallic-type catalysts, etc., more specific examples of which include, but are not limited to, triethylenediamine, bis (dimethylaminoethyl) ether, cyclohexylmethyl tertiary amine, pentamethyldiethylenetriamine, triethylamine, tributylamine, dimethylethanolamine, N-ethylmorpholine, N-methylmorpholine, tin (II) acetate, tin (II) octoate, tin ethylhexanoate, tin laurate, dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin maleate, dioctyltin diacetate, tetrabutyltitanate, tetraisopropyl titanate, etc., and such catalysts may be used alone or in combination.
In the polyurethane foam of the present invention, the chain extender may be selected from commonly used chain extenders, and examples which may be cited include, but are not limited to, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, butylene glycol, diethylene glycol, dipropylene glycol, cyclohexanediol, hydrogenated bisphenol A, ethylene glycol amine, etc., and such chain extenders may be used alone or in combination.
As a preferred embodiment of the present invention, the a isocyanate-reactive component may further comprise a foam stabilizer, which may be selected from conventional foam stabilizers, examples of which include, but are not limited to, silicone-based polymers and the like, and more specific examples of which include, but are not limited to, polysiloxane-alkylene oxide block copolymers and the like.
In a preferred embodiment of the present invention, the a isocyanate-reactive component comprises, based on the total mass of the a isocyanate-reactive component: a mixed polyol, a cross-linking agent, a foaming agent, a catalyst and a chain extender, wherein the mixed polyol comprises A1 and A2 and optional A3 and A4 polyols, and the contents of the components are as follows:
polytetramethylene ether glycol A1, the content of which is 10 to 40 percent, preferably 20 to 30 percent;
polyester polyol A2 in an amount of 10 to 60%, preferably 20 to 40%;
polyether polyol A3 in an amount of 0 to 70%, preferably 20 to 45%;
the content of the polymer polyol A4 is 0 to 40%, preferably 10 to 20%;
a crosslinking agent in an amount of 0.2 to 10%, preferably 0.5 to 5%;
a foaming agent in an amount of 0.2 to 18%, preferably 0.3 to 15%;
catalyst content of 0.8-3%, preferably 1.2-2%;
foam stabilizer in 0-1.2%, preferably 0.5-1%;
the content of the chain extender is 0.5-6%, preferably 2-4%.
Other commonly used additives may also optionally be used in the present invention, examples of which include, but are not limited to, flame retardants, antioxidants, coupling agents, smoke suppressants, pigments, antistatic agents, UV stabilizers, diluents, surface wetting agents, leveling agents, thixotropic agents, plasticizers, and the like.
The B isocyanate component may be selected from any commonly used organic isocyanate examples including, but not limited to, toluene Diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polyphenyl polymethylene Polyisocyanate (PMDI), 1, 5-Naphthalene Diisocyanate (NDI), hexamethylene Diisocyanate (HDI), methylcyclohexyl diisocyanate, 4' -dicyclohexylmethane diisocyanate, isophorone diisocyanate (IPDI), terephthalyl diisocyanate (PPDI), terephthalylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), and the like, as well as derivatives of such isocyanates. The above-mentioned organic isocyanates may be used singly or in combination. The B isocyanate component may be obtained by commercial purchasing or may be prepared by methods commonly used in the art.
Preferably, the NCO content of the B isocyanate component is 22 to 33% by weight, preferably 25 to 28% by weight.
The molar ratio of active hydrogen atoms in the isocyanate-reactive component A to isocyanate groups in the isocyanate component B is from 0.8 to 1.1:1, preferably from 0.95 to 1.05:1.
In a preferred embodiment of the present invention, the self-skinning polyurethane foam meets the following requirements:
product density: 150-300kg/m 3 Test standard: ISO 845:2006;
shore a hardness: 25-70, test standard: GB/T531.1-2008;
skin thickness: 0.3-2mm;
peel tear strength: 2.5-11KN/m, test standard: ISO 34-1:2015;
skin tensile strength: 0.6-2.85MPa, test standard: ISO 37:2011;
elongation at break of skin: 80-150%, test standard: ISO 37:2011;
retention rate of physical properties after heat aging at 170 ℃ for 48 hours: more than or equal to 60 percent; the physical property retention rate is the percentage of the tearing strength, the tensile strength and the elongation at break after heat aging treatment compared with the data before aging;
retention rate of physical properties after heat aging at 150 ℃ for 168 hours: more than or equal to 70 percent; the physical property retention rate is the percentage of the tearing strength, the tensile strength and the elongation at break after heat aging treatment compared with the data before aging;
core sound absorption coefficient: not less than 0.5 (tested by standing wave tube not less than 1000 HZ), test standard: GB/T18696.2-2002.
The preparation method of the self-skinning polyurethane foam comprises the following preparation steps:
and uniformly mixing the isocyanate reactive component A and the isocyanate component B, pouring the mixture into a mold for foaming reaction, and obtaining the self-skinning polyurethane foam after the reaction is finished.
The invention has the beneficial effects that:
the self-skinning polyurethane foam prepared according to the technical scheme of the invention has excellent heat resistance, sound absorption and mechanical properties, and can meet the requirements of application fields such as automobile engine covers, oil rail cladding and the like; the preparation process can be one-step molding, the process is simple and convenient, and the production efficiency is high.
Drawings
FIG. 1 is a graph showing the sound absorption properties of the foam sample obtained in example 3.
Detailed Description
The invention is further illustrated by the following examples.
Raw materials of examples and comparative examples:
polytetramethylene ether glycol A1-1, polymeric monomer tetrahydrofuran, functionality of 2, hydroxyl value of 112mgKOH/g;
polytetramethylene ether glycol A1-2, polymeric monomer tetrahydrofuran, functionality of 2, hydroxyl value of 56mgKOH/g;
polyester polyol A2-1, polycaprolactone polyol, neopentyl glycol as initiator and epsilon-caprolactone as monomer with hydroxyl value of 112mgKOH/g;
polyester polyol A2-2, polycaprolactone polyol, neopentyl glycol as initiator and epsilon-caprolactone as monomer with hydroxyl value of 56mgKOH/g;
polyether polyol A3-1, initiator glycerin, copolymerization of ethylene oxide and propylene oxide, hydroxyl value of 35mgKOH/g, and Wanhua chemical production;
polyether polyol A3-2, initiator glycerin, copolymerization of ethylene oxide and propylene oxide, hydroxyl value 28mgKOH/g, and Wanhua chemical production;
the polymer polyol A4-1 takes glycerol as an initiator, ethylene oxide and propylene oxide are copolymerized, acrylonitrile and styrene are grafted, the hydroxyl value is 24mgKOH/g, and the solid content is 20%;
the polymer polyol A4-2 takes glycerol as an initiator, ethylene oxide and propylene oxide are copolymerized, acrylonitrile and styrene are grafted, the hydroxyl value is 21mgKOH/g, and the solid content is 40%;
homemade crosslinker 1: the amine number is: 261mgKOH/g;
homemade crosslinking agent 2: the amine number is: 263mgKOH/g;
foaming agent: water, cyclopentane;
catalyst: triethylenediamine, dimethylethanolamine;
chain extender: ethylene glycol;
foam stabilizer B8715, produced by Yingchuang, germany;
color paste: black paste, produced by Guangzhou Ai Ke New Material Co., ltd;
and B isocyanate component: WANNATE8629 has NCO content of 25.5-26.5%, and is produced by Wanhua chemistry; WANNATE8627 has an NCO content of 27.0-28.0% and is produced by Wanhua chemistry.
The preparation method of the self-made cross-linking agent comprises the following steps:
crosslinking agent 1
129g of 1,3, 5-cyclohexane triamine (Wohan Jinyu biotechnology Co., ltd.) was added to the flask under nitrogen atmosphere, and stirring was started; to the flask were added 0.03g of sodium ethoxide and 0.02g of potassium tert-butoxide; 516.54g of diethyl maleate is slowly added into the flask in a dropwise manner, the mixture in the flask is heated to 60 ℃ for reaction after stirring and reacting for 2 hours, and the cross-linking agent 1 is obtained after cooling and discharging after reacting for 70 hours.
Crosslinking agent 2
123.16g of 1,3, 5-triaminobenzene is added into a flask under the nitrogen atmosphere, and stirring is started; to the flask were added 0.03g of sodium ethoxide and 0.02g of potassium tert-butoxide; 516.54g of diethyl maleate is slowly added into the flask in a dropwise manner, the mixture in the flask is heated to 95 ℃ for reaction after stirring and reacting for 2 hours, and the cross-linking agent 2 is obtained after cooling and discharging after reacting for 80 hours.
Examples and comparative examples preparation methods:
according to the types and weight parts of the components in the table 1, adding the raw materials of the component A into a reactor, stirring uniformly, controlling the temperature of the raw materials to be 25-30 ℃, setting the reaction ratio of the active hydrogen atoms in the isocyanate reactive components A to the isocyanate groups in the isocyanate reactive components B to be 1:1, mixing by adopting high-pressure equipment, pouring into a mould, maintaining the temperature of the mould to be 40-50 ℃, and opening the mould after maintaining the pressure for 4 minutes to obtain the polyurethane material.
Among them, the B isocyanate component used in examples 1,3,5, and 7 and comparative examples 1 and 3 was WANNATE8629, and the B isocyanate component used in examples 2, 4, and 6 and comparative example 2 was WANNATE8627.
TABLE 1
Table 1 (subsequent)
The polyurethane materials prepared in examples and comparative examples were tested for mechanical properties after being left at room temperature for 24 hours.
The properties and test criteria of the example and comparative polyurethane materials are shown in Table 2.
TABLE 2 physical Property test results
TABLE 2 physical Property test results (follow-up)
* And (3) injection: the non-test data is that the foam is not subjected to physical property test after heat aging and is powdered or deformed seriously.
TABLE 3 retention of Properties after thermal aging (%)
* And (3) injection: the sample becomes soft after heat aging, and the elongation at break increases, so that the retention of physical properties after heat aging may be more than 100%.
TABLE 3 retention of physical Properties after thermal aging (subsequent)
* And (3) injection: the non-test data is that the foam is not subjected to physical property test after heat aging and is powdered or deformed seriously.
By comparing physical property data and heat aging data of the embodiment with those of the comparative example, the optimized formula polytetramethylene glycol, polycaprolactone polyol and polyester amine cross-linking agent are adopted and are matched with other components such as polyether polyol, polymer polyol and the like for use, so that the heat aging resistance of the foam can be greatly improved while the foam has good mechanical properties, the retention rate of the physical property of the foam after heat aging at 150 ℃ for 168 hours is more than 70%, the retention rate of the physical property of the foam after heat aging at 170 ℃ for 48 hours is more than 60%, and the application technical requirements of polyurethane self-skinning engine cover products are met.
For the foam samples obtained in example 3, standing wave tube test was used, test criteria: GB/T18696.2-2002, the core facing the sound source, gives sound absorption data as shown in FIG. 1.

Claims (14)

1. A self-skinning polyurethane foam obtained from the reaction of an isocyanate-reactive component comprising a mixed polyol, a crosslinker, a blowing agent, a catalyst, a chain extender, and a B isocyanate component;
wherein the mixed polyol comprises polytetramethylene ether glycol A1 and polyester polyol A2;
the cross-linking agent has the following structure:
wherein X is selected from aliphatic linking groups with a linear structure, aliphatic linking groups with a cyclic structure, aromatic linking groups, or aliphatic linking groups with hetero atoms;
r is an organic group inert to isocyanate groups and is selected from saturated aliphatic groups.
2. The polyurethane foam according to claim 1, wherein the aliphatic linking group having a cyclic structure is a cyclic structure having 5 to 12 carbon atoms, a double-ring structure, or a multi-ring structure; the aromatic connecting group is of a cyclic structure, a double-ring structure or a multi-ring structure with 6-20 carbon atoms;
r is a saturated aliphatic linking group with a straight-chain structure and a carbon number of 2-4.
3. The polyurethane foam according to claim 2, wherein the aliphatic linking group having a cyclic structure is selected from cyclopentane, cyclohexane, methylcyclohexane; the aromatic linking group is selected from benzene, toluene, ethylbenzene and diphenylmethane;
r is ethyl.
4. The polyurethane foam according to claim 1, wherein the amine value of the crosslinking agent is 120 to 310mgKOH/g.
5. The polyurethane foam according to claim 1, wherein the polytetramethylene ether glycol A1 has a hydroxyl value of 28 to 224mgKOH/g; the polyester polyol A2 is selected from polyester polyol obtained by polymerization reaction of polyol and polybasic acid, or polyester polyol obtained by polymerization reaction of anhydride and polyol, or polyester polyol obtained by ring-opening polymerization of lactone by taking polyol as initiator.
6. The polyurethane foam according to claim 5, wherein the polytetramethylene ether glycol A1 has a hydroxyl value of 56 to 112mgKOH/g; the polyester polyol A2 is: the polyester polyol is obtained by ring-opening polymerization of lactone by taking polyol as an initiator, and the hydroxyl value is 22-336 mgKOH/g.
7. The polyurethane foam according to claim 6, wherein the hydroxyl value of the polyester polyol A2 is 28 to 224mgKOH/g, the initiator for synthesizing the polyester polyol A2 is neopentyl glycol, and the lactone is epsilon-caprolactone.
8. The polyurethane foam according to claim 1, wherein the mixed polyol optionally further comprises a polyether polyol A3, a polymer polyol A4, the polyether polyol A3 being polymerized from an initiator with propylene oxide and/or ethylene oxide, having a functionality of 2 to 8 and a hydroxyl number of 24 to 240mgKOH/g;
the functionality of the polymer polyol A4 is 2-3, the hydroxyl value is 18-30 mgKOH/g, and the solid content is 15-45 wt%.
9. The polyurethane foam according to claim 8, wherein the polyether polyol A3 has a functionality of 3 and a hydroxyl number of 28-35mgKOH/g.
10. The polyurethane foam according to claim 1, wherein the blowing agent comprises a chlorofluorocarbon blowing agent, an aliphatic hydrocarbon, water, and/or:
the catalyst comprises an amine catalyst, an organometallic catalyst, and/or:
the chain extender comprises ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, butanediol, diethylene glycol, dipropylene glycol, cyclohexanediol, hydrogenated bisphenol A and ethylene glycol amine.
11. Polyurethane foam according to any of claims 1 to 10, characterized in that the following components are present, calculated on the total mass of the a isocyanate-reactive components:
polytetramethylene ether glycol A1 with the content of 10 to 40 percent;
polyester polyol A2 with the content of 10 to 60 percent;
polyether polyol A3 with the content of 0-70 percent;
the content of the polymer polyol A4 is 0-40%;
a cross-linking agent with the content of 0.2-10%;
the content of the foaming agent is 0.2-18%;
catalyst, the content is 0.8-3%;
foam stabilizer with content of 0-1.2%;
the content of the chain extender is 0.5-6%.
12. The polyurethane foam according to claim 11, wherein the contents of the components are as follows, based on the total mass of the a isocyanate-reactive component:
polytetramethylene ether glycol A1 with the content of 20 to 30 percent;
the content of the polyester polyol A2 is 20-40%;
polyether polyol A3 with the content of 20-45 percent;
the content of the polymer polyol A4 is 10-20 percent;
a cross-linking agent with the content of 0.5-5%;
the content of the foaming agent is 0.3-15%;
a catalyst, the content of which is 1.2-2%;
foam stabilizer with content of 0.5-1%;
the content of the chain extender is 2-4%.
13. The polyurethane foam of claim 1, wherein the B isocyanate component comprises toluene diisocyanate, diphenylmethane diisocyanate, polyphenyl polymethylene polyisocyanate, 1, 5-naphthalene diisocyanate, hexamethylene diisocyanate, methylcyclohexyl diisocyanate, 4' -dicyclohexylmethane diisocyanate, isophorone diisocyanate, terephthalyl diisocyanate, tetramethylxylylene diisocyanate, and derivatives of these isocyanates.
14. The polyurethane foam according to claim 1, wherein the molar ratio of active hydrogen atoms in the a isocyanate-reactive component to isocyanate groups in the B isocyanate component is from 0.8 to 1.1:1.
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CN107353409A (en) * 2016-05-05 2017-11-17 安徽丰原药业股份有限公司 Dendrimer compound and its preparation method and application
KR20180036827A (en) * 2016-09-30 2018-04-10 석승국 Method of coating a surface of a building interior or exterior using a coating composition containing non-yellowing polyaspartic urea
CN108164737A (en) * 2017-12-27 2018-06-15 上海东大聚氨酯有限公司 A kind of combined polyether, polyurethane raw material composition, polyurethane foam and preparation method thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103347919A (en) * 2011-02-09 2013-10-09 拜耳材料科技股份有限公司 Tissue adhesive based on trifunctional aspartates
CN107353409A (en) * 2016-05-05 2017-11-17 安徽丰原药业股份有限公司 Dendrimer compound and its preparation method and application
KR20180036827A (en) * 2016-09-30 2018-04-10 석승국 Method of coating a surface of a building interior or exterior using a coating composition containing non-yellowing polyaspartic urea
CN108164737A (en) * 2017-12-27 2018-06-15 上海东大聚氨酯有限公司 A kind of combined polyether, polyurethane raw material composition, polyurethane foam and preparation method thereof

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