Process for preparing rigid polyurethane foams

文档序号：354633 发布日期：2021-12-07 浏览：14次中文

阅读说明：本技术 制备硬质聚氨酯泡沫的方法 (Process for preparing rigid polyurethane foams ) 是由童俊于 2020-06-01 设计创作，主要内容包括：本发明涉及一种制备硬质聚氨酯泡沫的方法,该方法所制得的硬质聚氨酯泡沫及其在聚氨酯复合材料中的应用。(The invention relates to a method for preparing rigid polyurethane foam, the rigid polyurethane foam prepared by the method and application thereof in polyurethane composite materials.)

1. A method for preparing rigid polyurethane foam, which is prepared by reacting a polyurethane reaction system comprising the following components:

component A, comprising: a polyisocyanate;

component B, comprising:

B1) polyether polyols having a functionality of from 3.0 to 8.0, preferably from 3.0 to 6.0, a weight-average molecular weight of from 350-900g/mol, preferably from 400-900g/mol (test method cf. ISO 14900-2017), in an amount of from 50 to 80pbw, preferably from 55 to 75pbw, based on 100pbw of component B;

B2) a polyamine-initiated hydroxyl-terminated polyether polyol having a functionality of 4.0 and a weight average molecular weight of 550-750g/mol, preferably 550-700g/mol (test method cf. ISO 14900-2017), in an amount of 6-15pbw, preferably 6-12pbw, based on 100pbw of component B;

B3) an aromatic polyester polyol having a functionality of from 2.0 to 2.4 and a weight average molecular weight of from 300-650g/mol, preferably from 300-600g/mol (test method cf. ISO 14900-2017), in an amount of from 3.0 to 10.0pbw, preferably from 3.0 to 9.0pbw, based on 100pbw of component B;

B4) polyetheramines having a functionality of from 2 to 3 and a weight-average molecular weight of from 1200-2000g/mol, preferably from 1300-2000g/mol (test methods cf. ISO 14900-2017).

2. The method of claim 1, wherein said component a comprises:

A1) isocyanate with functionality more than or equal to 2, preferably at least one of polymeric diphenylmethane diisocyanate, 4 '-diisocyanate-diphenylmethane, 2, 4' -diisocyanate-diphenylmethane or prepolymer or mixture thereof.

3. The process as claimed in claim 1 or 2, wherein the B4) polyetheramine content is from 2 to 10pbw, preferably from 2 to 7pbw, based on 100pbw of component B.

4. The method of claim 1 or 2, wherein said component B further comprises:

B5) at least one tertiary ammonia based catalyst in an amount of 0.8 to 2.5pbw, preferably 0.8 to 2.2pbw, based on 100pbw of component B.

5. The process as claimed in claim 1 or 2, wherein the polyurethane reaction system with the addition of polyetheramine produces rigid polyurethane foams having an increase in adhesion of at least 15%, preferably at least 18%, over rigid polyurethane foams produced without the addition of polyetheramine.

6. The method of claim 1 or 2, wherein said component B further comprises:

B6) from 0.7 to 2.0pbw, preferably from 0.7 to 1.8pbw, of water based on 100pbw of component B.

7. The method of claim 1 or 2, wherein said component B further comprises:

B7) at least one physical blowing agent in an amount of 8.0 to 25pbw, preferably 8.0 to 22pbw, based on 100pbw of component B.

8. The method according to claim 7, wherein the physical blowing agent is at least one selected from the group consisting of n-pentane, cyclopentane, isopentane, pentafluoropropane, hexafluorobutane and chlorotrifluoroethylene, or any mixture thereof.

9. A rigid polyurethane foam obtained by the process for producing a rigid polyurethane foam according to any one of claims 1 to 8.

10. Rigid polyurethane foam according to claim 9, characterized in that the core density of the rigid polyurethane foam is from 37 to 100kg/m3, preferably from 37 to 70kg/m3 (test method ISO 291: 1997).

11. Rigid polyurethane foam according to claim 9 or 10, wherein the adhesion of the rigid polyurethane foam produced by the polyurethane reaction system with added polyetheramine is increased by 15% or more, preferably 18% or more, compared to a rigid polyurethane foam produced by a polyurethane reaction system without added polyetheramine.

12. Rigid polyurethane foam according to claim 9 or 10, characterized in that the adhesion of the rigid polyurethane foam is not less than 29N, preferably not less than 30N.

13. Use of a rigid polyurethane foam according to any one of claims 9 to 12 in polyurethane composites.

14. A polyurethane product comprising the rigid polyurethane foam of any one of claims 9 to 12.

15. The polyurethane product of claim 14, wherein the polyurethane product is selected from the group consisting of a refrigerator, a freezer, a cooler, a warmer, an incubator, and a rigid polyurethane composite profile.

Technical Field

The present invention relates to a process for the preparation of rigid polyurethane foams, the rigid polyurethane foams obtained by this process and their use for moulding rigid polyurethane composites and heat insulation materials.

Background

Rigid polyurethane foam is widely applied to the fields of buildings, transportation, household appliances, sports equipment and the like as a mature technical product at present. It is usually prepared by mixing an isocyanate component (e.g., PAPI) with an active hydrogen-containing substance (e.g., polyether polyol, polyester polyol, small molecule aminopolyol, small molecule polyalcohol amine, etc.), a surfactant, a catalyst (e.g., tertiary ammonia, quaternary ammonium salt, alkali metal carboxylate, etc.), a blowing agent (e.g., water, pentane, hydrofluorocarbon, vinyl hydrochlorofluorocarbon, etc.), and then spraying, casting, pouring, etc. to form a rigid foam. For the application fields requiring foam molding, the demolding time needs to be controlled due to the need of considering the production efficiency. Thus, generally, within a defined period of time for curing and demolding, the rigid foam does not reach a theoretical degree of complete curing, and the foam core has been allowed to assume a relatively high temperature for a short period of time after demolding to place the core foam in a near viscoelastic state. If the initial strength of the foam is lower than the internal pressure of the foam core upon expansion, the foam will experience a much greater thickness-wise expansion than expected (i.e., post expansion).

Attempts have been made to solve the problem of excessive post-expansion by increasing the demold time of the molding process to increase the degree of cure of the foam. Attempts have also been made to reduce the post-expansion of the foam by increasing the average degree of crosslinking of the active hydrogen reactive component, for example by replacing the long chain polyol used to impart the appropriate flexibility to the rigid foam with a short chain polyether polyol of high degree of crosslinking, but this sacrifices the toughness of the rigid foam and even the adhesion of the foam to the substrate/facestock.

CN1578797A discloses a method for preparing rigid polyurethane foams: comprising reacting an isocyanate component with at least one multifunctional (meth) acrylate compound containing an average of at least 2 acrylate or methacrylate groups per molecule and having a mass per acrylate or methacrylate group of 300 daltons (dalton) or less (111) at least one catalyst for the reaction of a polyol or water with a polyisocyanate in the presence of a catalyst and subjecting the mixture to conditions sufficient to cause the isocyanate component to react with the polyol component and the multifunctional (meth) acrylate compound to polymerize, thereby forming a rigid polyurethane foam.

CN1178803A discloses a process for producing rigid polyurethane foams having improved heat distortion resistance and reduced thermal conductivity, which is prepared by adding ethylene oxide and/or propylene oxide to a hexitol or a mixture of hexitols, with a polyisocyanate and a compound containing hydrogen atoms reactive with cyanate esters. Wherein the total hexitol content of the polyol mixture is from 15 to 30% by weight, based on the polyol mixture, and the further 1-polyol is prepared by addition of ethylene oxide and/or propylene oxide to one or more aromatic amines, and the total amine content of the polyol mixture is from 1 to 10% by weight, based on the polyol mixture.

CN 103214651 a discloses a technology for preparing polyurethane rigid foam by using short-chain polyether polyol and aromatic polyester polyol with high proportion of aliphatic diamine as initiator, which is applied to outdoor waterproof and heat preservation of buildings with weather resistance and waterproof requirements.

Despite the above disclosures, there remains a need in the industry for an optimized process for preparing rigid polyurethane foams.

Disclosure of Invention

In one aspect of the present invention, there is provided a method for preparing a rigid polyurethane foam by reacting a polyurethane reaction system comprising:

component A, comprising: a polyisocyanate;

component B, comprising:

B4) a functionality of 2-3, a weight-average molecular weight of 1200-2000g/mol, preferably 1300-2000g/mol (test method is referred to ISO 14900-2017).

Preferably, the component a comprises:

Preferably, the component B4) is present in an amount of 2 to 10pbw, preferably 2 to 7pbw, based on 100pbw of component B.

Preferably, the component B further comprises:

B5) at least one tertiary ammonia based catalyst in an amount of 0.8 to 2.5pbw, preferably 0.8 to 2.2pbw, based on 100pbw of component B.

B6) From 0.7 to 2.0pbw, preferably from 0.7 to 1.8pbw, of water based on 100pbw of component B.

Preferably, the component B further comprises:

B7) at least one physical blowing agent in an amount of 8.0 to 25pbw, preferably 8.0 to 22pbw, based on 100pbw of component B.

B8) At least one small chain extender, preferably diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, in an amount of 1 to 2.4pbw, preferably 1.2 to 2.4pbw, based on 100pbw of component B.

Preferably, the component B further comprises:

B9) at least one silicone surfactant, preferably a silicone oil, in an amount of 1.0 to 2.5pbw, preferably 1.2 to 2.5pbw, based on 100pbw of component B.

Preferably, the component B further comprises:

preferably, the component B further comprises:

B10) at least one organometallic catalyst in an amount of 0.1 to 0.7pbw, preferably 0.1 to 0.6pbw, based on 100pbw of component B.

Preferably, the physical blowing agent is selected from at least one of n-pentane, cyclopentane, isopentane, pentafluoropropane HFC-245fa (CF3CH2CHF2), hexafluorobutane HFC-365mfc (CF3CH2CF2CH3), chlorotrifluoroethylene LBA (ClCHCHCF3) or any mixture thereof.

Preferably, the adhesive force of the rigid polyurethane foam prepared by the polyurethane reaction system added with the polyether amine is increased by more than or equal to 15 percent, preferably more than or equal to 18 percent compared with the adhesive force of the rigid polyurethane foam prepared by the polyurethane reaction system without the polyether amine.

We have found that the process for producing rigid polyurethane foams according to the present invention, rigid polyurethane foams produced from a reaction system comprising polyetheramine and isocyanate, polyol and the like components suitable therefor, does not require the use of expensive long-chain polyether polyols which are conventionally added, and rigid polyurethane foams having more excellent physical properties are obtained. Specifically, on the one hand, the adhesion of the foam is enhanced, and on the other hand, the expansion rate of the foam after demolding is well controlled. The cost is saved, and simultaneously, more satisfactory rigid polyurethane foam is prepared.

In still another aspect of the present invention, there is provided a rigid polyurethane foam prepared by the method for preparing a rigid polyurethane foam of the present invention.

Preferably, the rigid polyurethane foams have a core density of from 37 to 100kg/m3, preferably from 37 to 70kg/m3 (test method ISO 291: 1997).

Preferably, the adhesive force of the hard polyurethane foam is more than or equal to 29N, preferably more than or equal to 30N (test method: a tensiometer vertical drawing method, and the judgment is carried out according to the foam adhesion condition of the adhesive interface).

In a further aspect of the present invention, there is provided a use of the rigid polyurethane foam in a polyurethane composite. Preferably, the polyurethane composite is a molded rigid polyurethane composite.

In a further aspect of the present invention, there is provided a polyurethane product comprising a rigid polyurethane foam according to the present invention.

Preferably, the polyurethane product is selected from the group consisting of a refrigerator, a freezer, a holding tank, an incubator, and a rigid polyurethane composite profile.

Detailed Description

The following terms used in the present invention have the following definitions or explanations.

pbw refers to the mass parts of each component of the polyurethane reaction system;

functionality, means according to the industry formula: functionality ═ hydroxyl number^＊Molecular weight/56100; wherein, the molecular weight is measured by GPC high performance liquid chromatography, and the test method is referred to GB/T21863-2008.

Components of polyurethane foam reaction system

A) Polyisocyanates

Any organic polyisocyanate may be used in the preparation of the flexible high resilience polyurethane foam of the present invention, including aromatic, aliphatic and cycloaliphatic polyisocyanates and combinations thereof. The polyisocyanate can be represented by the general formula R (NCO) n, wherein R represents an aliphatic hydrocarbon group having 2 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 15 carbon atoms, an araliphatic hydrocarbon group having 8 to 15 carbon atoms, and n is 2 to 4.

Useful polyisocyanates include, but are not limited to, vinyl diisocyanate, tetramethylene 1, 4-diisocyanate, Hexamethylene Diisocyanate (HDI), dodecyl 1, 2-diisocyanate, cyclobutane 1, 3-diisocyanate, cyclohexane 1, 4-diisocyanate, 1-isocyanato 3, 3, 5-trimethyl 5-isocyanatomethylcyclohexane, hexahydrotoluene 2, 4-diisocyanate, hexahydrophenyl 1, 3-diisocyanate, hexahydrophenyl 1, 4-diisocyanate, perhydrodiphenylmethane 2, 4-diisocyanate, perhydrodiphenylmethane 4, 4-diisocyanate, phenylene 1, 3-diisocyanate, phenylene 1, 4-diisocyanate, stilbene 1, 4-diisocyanate, mixtures thereof, and mixtures thereof, 3, 3-dimethyl-4, 4-diphenyldiisocyanate, toluene-2, 4-diisocyanate (TDI), toluene-2, 6-diisocyanate (TDI), diphenylmethane-2, 4 ' -diisocyanate (MDI), diphenylmethane-2, 2 ' -diisocyanate (MDI), diphenylmethane-4, 4 ' -diisocyanate (MDI), mixtures of diphenylmethane diisocyanates and/or homologues of diphenylmethane diisocyanates having more rings, polyphenylmethane polyisocyanates (polymeric MDI), naphthylene-1, 5-diisocyanates (NDI), their isomers, and any mixtures thereof.

Useful polyisocyanates also include isocyanates modified with a carbonized diamine, allophanate or isocyanate, preferably, but not limited to, diphenylmethane diisocyanate, carbonized diamine modified diphenylmethane diisocyanate, isomers thereof, mixtures thereof and isomers thereof.

When used in the present invention, the polyisocyanate includes an isocyanate dimer, trimer, tetramer or a combination thereof.

In a preferred embodiment of the present invention, the isocyanate comprises:

B) Polyhydric alcohols

The polyol of the present invention may be a polyether polyol, a polyester polyol, a polycarbonate polyol and/or a mixture thereof.

The polyol of the present invention is preferably one or more polyether polyols, wherein at least one polyether polyol is a polyether polyol having a polyfunctional small molecule alcohol as an initiator. The polyether polyol has a functionality of 2 to 8, preferably 3 to 6, and a hydroxyl value of 20 to 1200KOH/g, preferably 20 to 800 mgKOH/g.

The polyether polyols may be prepared by known processes. Ethylene oxide or propylene oxide is typically prepared with ethylene glycol, 1, 2-propylene glycol, 1, 3-propylene glycol, diethylene glycol, glycerol, trimethylolpropane, pentaerythritol, triethanolamine, toluenediamine, sorbitol, sucrose, or any combination thereof as a starter.

In addition, the polyether polyol can be prepared by reacting at least one alkylene oxide containing 2 to 4 carbon atoms with a compound containing 2 to 8, preferably, but not limited to, 3 to 6 active hydrogen atoms or other reactive compounds in the presence of a catalyst.

Examples of such catalysts are alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, or alkali metal alkoxides such as sodium methoxide, sodium ethoxide or potassium isopropoxide.

Useful olefin oxides include, preferably but are not limited to, tetrahydrofuran, ethylene oxide, 1, 2-propylene oxide, 1, 2-butylene oxide, 2, 3-butylene oxide, styrene oxide, and any mixtures thereof.

Useful active hydrogen atom containing compounds include polyhydroxy compounds, preferably, but not limited to, water, ethylene glycol, 1, 2-propylene glycol, 1, 3-propylene glycol, diethylene glycol, trimethylolpropane, any mixture thereof, more preferably polyhydric, especially trihydric or higher alcohols, such as glycerol, trimethylolpropane, pentaerythritol, sorbitol and sucrose. Useful active hydrogen atom-containing compounds also include, preferably but not limited to, organic dicarboxylic acids such as succinic acid, adipic acid, phthalic acid and terephthalic acid, or aromatic or aliphatic substituted diamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, propylenediamine, butylenediamine, hexamethylenediamine or toluenediamine.

Other reactive compounds that may be used include ethanolamine, diethanolamine, methylethanolamine, ethylethanolamine, methyldiethanolamine, ethyldiethanolamine, triethanolamine, and ammonia.

The polyether polyol prepared by using amine as a starter comprises a compound obtained by reacting amine as a starter with an alkylene oxide compound.

The term "alkylene oxide compound" as used in the present invention generally refers to compounds having the following general formula (I):

wherein R is₁And R₂Independently selected from H, C₁～C₆Straight and branched chain alkyl groups as well as phenyl and substituted phenyl groups.

Preferably, R₁And R₂Independently selected from H, methyl, ethyl, propyl and phenyl.

The person skilled in the art knows the preparation of "alkylene oxide compounds", which can be obtained, for example, by oxidation of alkylene compounds.

Examples of the alkylene oxide compounds useful in the present invention include, but are not limited to: ethylene oxide, 1, 2-propylene oxide, 1, 2-butylene oxide, 2, 3-butylene oxide, styrene oxide or mixtures thereof, with mixtures of ethylene oxide and 1, 2-propylene oxide being particularly preferred.

The term "alkylene oxide compound" as used in the present invention also includes oxacycloalkanes, examples of which include, but are not limited to: tetrahydrofuran and oxetane.

As used herein, the term "amine" refers to a compound containing a primary amino group, a secondary amino group, a tertiary amino group, or a combination thereof. Examples of compounds useful as amines in the present invention include, but are not limited to, triethanolamine, ethylenediamine, tolylenediamine, diethylenetriamine, triethylenetetramine, and derivatives thereof, preferably ethylenediamine, tolylenediamine, and particularly preferably tolylenediamine.

The polyester polyol is prepared by reacting dicarboxylic acid or dicarboxylic anhydride with polyhydric alcohol. The dicarboxylic acid is preferably, but not limited to, aliphatic carboxylic acid containing 2 to 12 carbon atoms, such as: succinic acid, malonic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanecarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, and mixtures thereof. The dibasic acid anhydride is preferably, but not limited to, phthalic anhydride, tetrachlorophthalic anhydride, maleic anhydride, and mixtures thereof. The polyhydric alcohol is preferably, but not limited to, ethylene glycol, diethylene glycol, 1, 2-propylene glycol, 1, 3-propylene glycol, dipropylene glycol, 1, 3-methylpropylene glycol, 1, 4-butylene glycol, 1, 5-pentanediol, 1, 6-hexanediol, neopentyl glycol, 1, 10-decanediol, glycerol, trimethylolpropane, or a mixture thereof. The polyester polyol also comprises polyester polyol prepared from lactone. The polyester polyol prepared from lactone is preferably, but not limited to, a polyester polyol prepared from epsilon-caprolactone.

The polycarbonate polyol is preferably, but not limited to, a polycarbonate diol. The polycarbonate diol may be prepared by reacting a diol with a dialkyl or diaryl carbonate or phosgene. The diol is preferably, but not limited to, 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, diethylene glycol, trioxymethylene glycol, or a mixture thereof. The dialkyl or diaryl carbonate is preferably, but not limited to, diphenyl carbonate.

Preferably, the polyol of the present invention comprises at least one of the following components:

Foaming agent

The blowing agent of the present invention may be selected from various physical blowing agents and/or chemical blowing agents.

Useful blowing agents include water, halogenated hydrocarbons, and the like. Useful halohydrocarbons are preferably pentafluorobutane, pentafluoropropane, chlorotrifluoropropene, hexafluorobutene, HCFC-141 b (monofluorodichloroethane), HFC-365mfc (pentafluorobutane), HFC-245fa (pentafluoropropane), or any mixture thereof. Useful hydrocarbon compounds also include butane, pentane, Cyclopentane (CP), hexane, cyclohexane, heptane, and any mixture thereof. Preferably at least one of n-pentane, cyclopentane, isopentane, pentafluoropropane (HFC-245fa, CF3CH2CHF2), hexafluorobutane (HFC-365 mfc, CF3CH2CF2CH3), chlorotrifluoroethylene (LBA, ClCHCHCF F3), or any mixture thereof.

The blowing agent of the present invention preferably comprises: from 0.7 to 2.0pbw, preferably from 0.7 to 1.8pbw, of water based on 100pbw of component B.

Preferably, the component B further comprises: at least one physical blowing agent in an amount of 8.0 to 25pbw, preferably 8.0 to 22pbw, based on 100pbw of component B.

Catalyst and process for preparing same

The catalyst of the present invention preferably includes at least one of a tertiary amine-based catalyst and a metal catalyst. The tertiary amine catalyst includes, but is not limited to, one, two or more of triethylamine, tributylamine, dimethylethanolamine, bis (dimethylaminoethyl) ether, triethylenediamine, N-ethylmorpholine, N '-tetramethyl-ethylenediamine, pentamethyldiethylenetriamine, dimethylaminopropylenediamine, N' -tetramethyldipropylenetriamine, and weak acid-modified products of the amine catalysts. Preferably, the tertiary amine catalyst is present in an amount of from 0.8 to 2.5pbw, preferably from 0.8 to 2.2pbw, based on 100pbw of component B.

Preferably, the organometallic catalyst is selected from alkyltin mercaptides, alkyltin thioglycolates, long chain alkyltin carboxylates, cobalt naphthenate, alkali metal carboxylates, or any combination thereof. The organometallic catalyst is present in an amount of 0.1 to 0.7pbw, preferably 0.1 to 0.6pbw, based on 100pbw of component B.

Surface active agent

In an embodiment of the present invention, the polyurethane reaction system of the present invention further comprises at least one surfactant, preferably, but not limited to, an oxyalkylene copolymer derivative of siloxane. The surfactant is present in an amount of 1.0 to 2.5pbw, preferably 1.2 to 2.5pbw, based on 100pbw of component B.

Chain extender

The chain extender used in the present invention is selected from multifunctional alcohols or amines containing hydroxyl or amino and having low molecular weight, and the commonly used alcohol chain extenders include 1, 4-Butanediol (BDO), 1, 6-hexanediol, glycerol, trimethylolpropane, diethylene glycol (DEG), triethylene glycol, neopentyl glycol (NPG), sorbitol, Diethylaminoethanol (DEAE), etc. The small-molecule chain extender is preferably diethanolamine, triethanolamine, diisopropanolamine and triisopropanolamine, and the content of the small-molecule chain extender is 1-2.4pbw, preferably 1.2-2.4 pbw, based on 100pbw of the component B.

The polyurethane reaction system of the present invention also includes a polyetheramine. Polyetheramines (polyetheramines) are a class of polyolefin compounds having a flexible polyether backbone, terminated by primary or secondary amine groups. The basic structure of which contains at least one polyalkylene glycol function which is critical for its properties. The polyalkylene glycol functionality enhances the water solubility of the polyetheramine. The melting point and the viscosity of the polyetheramine are also influenced. Specifically, polyoxyethylene diamine, polyoxypropylene diamine, polyoxyethylene/oxypropylene diamine, polyoxypropylene triamine, polytetramethylene ether diamine, and the like can be included. Most of these compounds are obtained by chemical treatment of the terminal hydroxyl groups, starting from the corresponding polyether polyols. The polyetheramines can be classified into aromatic and aliphatic groups according to the difference in the structure of the hydrocarbon groups connected with the terminal amino groups. The polymer is usually light yellow or colorless transparent liquid at room temperature, has the advantages of low viscosity, low vapor pressure, high primary amine content and the like, can be dissolved in solvents such as ethanol, aliphatic hydrocarbons, aromatic hydrocarbons, esters, glycol ethers, ketones, water and the like, and is a polymer with a polyether structure as a main chain and an amino group as a terminal active functional group. The polyether amine is obtained by ammoniating polyethylene glycol, polypropylene glycol or ethylene glycol/propylene glycol copolymer at high temperature and high pressure. In industrial production, polyetheramines can generally be prepared by ammonolysis and leaving group processes. The synthesis process of the polyether amine comprises a batch process and a continuous process. It is well known in the art that the production process adopted by Huntsman corporation is a continuous fixed bed process, and polyetheramine is catalytically synthesized by using a metal catalyst supported on a carrier.

The polyether amine can be used as a high-performance curing agent of epoxy resin, and is used for producing high-strength and high-toughness composite materials, coatings, ornaments, cleaning agents and the like. It is well known to those skilled in the art that in the field of polyurethane polyurea elastomers, polyetheramines are involved in the polymerization as the main starting material. But have not been used as curing agents or chain extenders in rigid polyurethane foam blowing systems.

Specifically, the polyurethane reaction system of the present invention comprises: B4) polyetheramines having a functionality of from 2 to 3 and a weight-average molecular weight of from 1200-2000g/mol, preferably from 1300-2000g/mol (test method cf. ISO 14900-2017), in an amount of from 2 to 10pbw, preferably from 2 to 7pbw, based on 100pbw of component B.

Through experiments, the method is surprisingly found to be simple and efficient, and the rigid polyurethane foam with more excellent physical properties is prepared by a reaction system containing the polyether amine and the components such as isocyanate, polyol and the like which are adaptive to the polyether amine. The method of the invention enhances the cohesive force of the prepared rigid polyurethane foam on one hand, and well controls the expansion rate of the rigid polyurethane foam after demoulding on the other hand.

Examples

Description of Performance test methods

The core density refers to the foam center density tested under the condition of excessive filling in a mould used in the manufacturing process of the polyurethane composite board, namely the density of the molded foam core; test methods were according to ISO 291: 1997;

the later expansion rate: a, B components were mixed and poured quantitatively into a temperature-controlled metal square mould, filled to a density of 50kg/m3 and the mould closed. And after the set curing time is 7 minutes, opening the mold and taking out the foam block, and after demolding for 3 minutes, placing the foam block on a thickness gauge to measure the real-time thickness value t of the center position of the foam block. The percentage of thickness expansion ((t-100). times.100%) with respect to the thickness of the mold 100mm is the post-expansion ratio (post-expansion) according to the present invention;

foam/substrate adhesion: a, B components were mixed and then quantitatively poured into a temperature-controlled square metal mold with a steel plate of 50mm × 50mm at the bottom, filled to a density of 50kg/m3, and the mold was closed. After a set maturation time of 7 minutes, the mould was opened and the foam block was removed. After demolding of the rigid polyurethane foam for 2 hours, interfacial drawing force measurements were carried out using a hand-held tensile tester. During measurement, the edge of the steel plate is hooked by a pull hook of the tension meter, and the tension direction is upward vertical to the plane of the steel plate. And in the process that the steel plate is completely stripped from the foam block by drawing, the maximum display value of the tension meter is recorded as the interface drawing adhesion, namely the adhesion of the invention.

The raw materials and test methods of the examples are illustrated below:

raw material 1-Desmophen4030, polyether polyol of sucrose/diethylene glycol composite initiator, functionality of 5.8 and hydroxyl value of 380mgKOH/g, which is purchased from Corsia Polymer (China) Co., Ltd

Raw material 2-DC4110, polyether polyol of sucrose/diethylene glycol composite initiator, functionality of 4.2 and hydroxyl value of 410mgKOH/g, purchased from Ningwu chemical Co., Ltd

3-Desmophen26HK69 as raw material, polyether polyol taking toluenediamine as initiator, functionality of 4.0 and hydroxyl value of 350 mgKOH/piece, and is purchased from Corsia polymer (China) Co., Ltd

Raw material 4-CAED-2000, polyetheramine, molecular weight 2000, functionality 2.0, hydroxyl value 56mgKOH/g, available from New materials GmbH of Chenghua, Yangzhou

5-DC-210 as raw material, polyether polyol with propylene glycol as initiator, functionality of 2.0 and hydroxyl value of 112mgKOH/g, purchased from Ningwu chemical Co., Ltd

Raw material 6-PS-3152, aromatic polyester polyol, molecular weight 360, functionality 2.0, hydroxyl value 315mgKOH/g, purchased from Jinlingtaipan chemical Co., Ltd

Starting material 7-Triethanolamine, technical grade, available from Pasteur Corp

Feedstock 8-PC-8(N, N-dimethylcyclohexylamine), available from Air Products

9-K-15 (potassium 2-isooctanoate), a raw material available from Air Products

Starting material 10-PC-41 tris- (bis-dimethylaminopropyl) hexahydrotriazine, available from Air Products

Starting material 11-cyclopentane, available from Shandong West Cold chemical Co., Ltd

Raw material 12-polyurethane rigid foam surfactant AK8830 available from Nanjing Meisite chemical Co., Ltd

Starting material 13-isocyanate Desmodur44V20, available from Corsia Polymer (China) Ltd

Preparation of rigid polyurethane foams

The isocyanate-reactive component B (i.e., component B) components shown in Table 1 were charged into a clean vessel and mixed uniformly by stirring with a turbine stirrer at 1000rpm for 3 minutes. At a set raw material temperature of about 23 + -2 deg.C, isocyanate component A and isocyanate reactive component B were weighed in the proportions shown in Table 1, mixed by mechanical stirring, and the mixture was injected into a metal square mold (300 mm. 100mm) having a temperature controlled to 40 deg.C, and subjected to reaction curing molding to obtain a rigid polyurethane foam.

TABLE 1 proportioning and Properties of examples and comparative examples

From the above experimental data, it is clear that the adhesion of the rigid polyurethane foam obtained by the polyurethane reaction system (examples 1 to 3) to which the polyetheramine was added is much improved as compared with the polyurethane reaction system to which no polyetheramine was added. In particular, examples 1 to 3 did not add any longer long-chain polyether polyol as conventionally added, but still obtained rigid polyurethane foams having more excellent physical properties.

Specifically, it can be seen that comparative example 1 is a typical molded polyurethane rigid foam system with a substrate protective outer layer for thermal insulation applications, which, by adding a certain amount of long chain polyether (raw material 5), can maintain a foam with proper substrate adhesion and also have acceptable post-demold expansion; if the amount of the long-chain polyether (raw material 5) is increased in order to obtain higher substrate adhesion, the foam becomes softer and the expansion rate deteriorates at the later stage of mold release; if the long-chain polyether (raw material 5) is reduced or even not added, a molded foam having a low expansion rate at the late stage of demolding can be obtained without fail, but the adhesion of the foam to the substrate is sacrificed, as shown in comparative example 2. In examples 1 to 3, by adding polyetheramine having a molecular weight of 2000 or less, the balance between the expansion after demolding and the adhesion to the substrate can be controlled.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

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Process for preparing rigid polyurethane foams

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