CN109400940B

CN109400940B - Conjugate polyethers, polyisocyanurate continuous sheets derived therefrom, and methods of making same

Info

Publication number: CN109400940B
Application number: CN201811137976.8A
Authority: CN
Inventors: 王光辉; 郭磊; 信延垒; 胡晨晨
Original assignee: SHANGHAI DONGDA POLYURETHANE CO Ltd
Current assignee: SHANGHAI DONGDA POLYURETHANE CO Ltd
Priority date: 2018-09-28
Filing date: 2018-09-28
Publication date: 2022-03-01
Anticipated expiration: 2038-09-28
Also published as: CN109400940A

Abstract

The invention relates to a combined polyether, a preparation method thereof and a preparation method of a Polyisocyanurate (PIR) continuous plate. The composite polyether comprises the following components in parts by weight: 70-90 parts of polyester polyol, 10-30 parts of polyether polyol, 2-3 parts of foam stabilizer, 1.5-3 parts of catalyst, 23-35 parts of flame retardant, 0.5-1 part of water and 15-31 parts of physical foaming agent. Wherein the polyester polyol has a functionality of 2, a hydroxyl value of 170 to 240mgKOH/g, and a viscosity of 9000 to 13000mPa · s at 25 ℃; a polyether polyol having a hydroxyl value of 200 to 235mgKOH/g and a viscosity of 80000 to 120000 mPas at 25 ℃. The sum of the mass parts of the polyol and the polyether polyol is 100 parts. The physical foaming agent comprises 10-16 parts of cyclopentane. The polyisocyanurate foamed plastic product prepared from the combined polyether has excellent compression strength, dimensional stability and oxygen index, is safe and environment-friendly, and has an Ozone Depletion Potential (ODP) of 0.

Description

Conjugate polyethers, polyisocyanurate continuous sheets derived therefrom, and methods of making same

Technical Field

The application relates to the field of polyisocyanurate chemical synthesis, in particular to environment-friendly high-flame-retardant combined polyether, a preparation method thereof and a preparation method of a polyisocyanurate continuous plate using the combined polyether.

Background

Polyisocyanurate rigid foams are high-molecular polymers formed by mixing a polyol and an isocyanate as the main raw materials with equipment or by hand under the action of a catalyst, a blowing agent, a surfactant and other auxiliaries. Rigid polyisocyanurate foams have been widely used in heat-insulating and reinforcing projects in various fields such as civil use, industry and military use.

In 9.2007, Montreal protocol agreed with solutions to accelerate elimination of hydrochlorofluorocarbon compounds (HCFCs) damaging the ozone layer, and a corresponding elimination plan was made, wherein the average of 2009 and 2010 was used as a baseline level, 10% of the baseline level was reduced in 2015, 35% of the baseline level was reduced in 2020, 67.5% of the baseline level was reduced in 2025, and 2030 stopped production and use worldwide, and HCFCs were prohibited in developed countries and regions such as European Union, United states, Japan, and Japan before 2010.

China, as the biggest HCFC production country (65 percent of the world) and the use country (40 percent of the world), also sets up a corresponding elimination schedule according to the Montreal protocol, and in 2009, except for special purposes, no new HCFC production facilities are required to be used in every place; starting to use and implement quota and record management of HCFCs in 2013, and applying quota for enterprises with annual usage of more than 100 t; the reduction of 17.5 percent of the base line level is realized in 2015, and the complete elimination of HCFCs in 3 sub-industries of refrigerator, freezer, refrigerated container and electric water heater is completed; the reduction is 30% in 2018; the reduction is 45% in 2020; the consumption of HCFCs in most sub-industries is eliminated after 80 percent reduction in 2023, and the industries such as solar water heaters, building boards and the like are listed in the sub-industries which are preferentially eliminated; in 2026, our country will forbid the use of HCFCs.

The elimination of HCFCs series is steadily carried out, main substitutes comprise pentane, cyclopentane, HFC (such as HFC-245fa, HFC-365mfc), total water, Ecomate, HFO series and the like, all substitutes have the advantages and the disadvantages, and the substitution schemes in different fields are different. In the aspect of polyisocyanurate plates, a cyclopentane system is an ideal substitute, but high flame retardant Polyisocyanurate (PIR) plates prepared by the cyclopentane system have poor compression strength, oxygen index and dimensional stability.

Therefore, the development of a novel flame-retardant combined polyether and a method for preparing a flame-retardant Polyisocyanurate (PIR) continuous plate by using the combined polyether is imperative to the field of polyisocyanurate plates.

Disclosure of Invention

The invention aims to solve the technical problems of poor compression strength, poor oxygen index and poor dimensional stability of a Polyisocyanurate (PIR) continuous plate, and provides an environment-friendly high-flame-retardant combined polyether and a method for preparing flame-retardant polyisocyanurate by using the combined polyether. According to the PIR continuous plate prepared by the application, the mass percent of the cyclopentane feeding amount in the total feeding amount is reduced by 3-8 points, and part of HFC-245fa is added, so that the compression strength, the oxygen index and the dimensional stability of the high-flame-retardant PIR continuous plate are improved.

In order to achieve the above object, the present application provides the following technical solutions.

In one aspect, the present application provides a composite polyether, comprising the following components in parts by mass: 70-90 parts of polyester polyol, 10-30 parts of polyether polyol, 2-3 parts of foam stabilizer, 1.5-3 parts of catalyst, 23-35 parts of flame retardant, 0.5-1 part of water and 15-31 parts of physical foaming agent. Wherein: a polyester polyol having a functionality of 2, a hydroxyl value of 170 to 240mgKOH/g, and a viscosity of 9000 to 13000mPa · s at 25 ℃; a polyether polyol having a hydroxyl value of 200 to 235mgKOH/g, a viscosity at 25 ℃ of 80000 to 120000mPa · s, and the sum of the mass parts of the polyether polyol and the polyol being 100 parts. The physical foaming agent comprises 10-16 parts of cyclopentane.

In some embodiments, the viscosity of the polyether polyol and the polyester polyol may each independently be a viscosity conventional in the art, such as a kinematic viscosity. The kinematic viscosity is generally measured using a rotational viscometer.

In some embodiments, the polyester polyol includes polyester polyol PEB-175. The polyester polyol PEB-175 is provided by Shandong-Nonwei polyurethane GmbH, and has a functionality of 2, a hydroxyl value of 170-230mgKOH/g, a viscosity of 9000-13000 mPa & s at 25 ℃, and a water content of less than 0.1 wt%.

In some embodiments, the polyether polyol is a flame retardant polyether polyol, including polyether polyol RB-79. The flame-retardant polyether polyol RB-79 is provided by Yabao chemical industry Co., Ltd, and has viscosity of 80000-120000 mPa & s at 25 ℃ and hydroxyl value of 200-235 mgKOH/g.

In some embodiments, the foam stabilizer comprises foam stabilizer L-6620 NT. Foam stabilizer L-6620NT is available from Mitigo high and New materials group, USA.

In some embodiments, the flame retardant is a flame retardant conventionally used in the art. In some particular embodiments, the flame retardant comprises one or more of tris (2-chloropropyl) phosphate (TCPP), tris (2-chloroethyl) phosphate (TCEP), and dimethyl methylphosphonate (DMMP).

In some embodiments, the physical blowing agent comprises 10 to 16 parts cyclopentane and 5 to 15 parts HFC-245 fa. Wherein the foaming agent cyclopentane CP has a molecular weight of 70g/mol and a boiling point of 49 ℃ and is purchased from Shanghai oceanographic chemical engineering Co. Blowing agent HFC-245fa, molecular weight 134g/mol, boiling point 15 deg.C, available from Honeywell.

In some embodiments, the water is preferably deionized water.

In some embodiments, the catalyst is a catalyst conventionally used in the art. In some particular embodiments, the catalyst is an amine catalyst or an organometallic catalyst, including one or more of N, N' -dimethylcyclohexylamine, potassium isooctanoate K-15, quaternary ammonium salt catalyst TMR-2.

In some specific embodiments, the catalyst is a composite catalyst comprising N, N '-dimethylcyclohexylamine, potassium isooctanoate K-15, quaternary ammonium salt catalyst TMR-2, wherein the mass ratio of N, N' -dimethylcyclohexylamine, potassium isooctanoate K-15 and quaternary ammonium salt catalyst TMR-2 is 1: 2-3: 1 to 2.

In another aspect, the present application also provides a method for preparing the composite polyether, which comprises pouring the components of the composite polyether into a container and uniformly mixing.

In some embodiments, the step of pouring the components of the composite polyether into a container to mix uniformly comprises stirring the components of the polyether at a temperature of 15-30 ℃ and a rotating speed of 400-600 r/min for 0.8-1.2 h.

In yet another aspect, the present application also provides a method of making a polyisocyanurate continuous sheet comprising the steps of: pouring the components of the combined polyether into a container and uniformly mixing; adding isocyanate into a container according to a proportion, uniformly mixing the isocyanate with the combined polyether, uniformly coating the mixture on a steel plate preheated to a set temperature, and feeding the steel plate into a laminating machine for curing to obtain the polyisocyanurate continuous plate.

In some embodiments, the mass ratio of the conjugate polyether to the isocyanate is 1:1.5 to 2.5.

In some embodiments, the isocyanate is diphenylmethane diisocyanate, model No. PM400, viscosity 400mpa.s, and-NCO content 30.5 to 32%, available from Vanda Chemicals.

In some embodiments, the set temperature of the steel sheet is in the range of 35 to 40 ℃.

The above preferred conditions can be combined arbitrarily to obtain preferred examples of the present application without departing from the common general knowledge in the field.

Compared with the prior art, the beneficial effect of this application lies in:

(1) the foaming agent used by the composite polyether is environment-friendly, and the Ozone Depletion Potential (ODP) is 0;

(2) the combined polyether reduces the mass percent of the cyclopentane feeding amount in the total feeding amount by 3-8 points, and adds part of HFC-245fa, so that the produced continuous board has excellent compression strength, dimensional stability and oxygen index.

Detailed Description

Unless otherwise indicated, implied from the context, or customary in the art, all parts and percentages herein are by weight and the testing and characterization methods used are synchronized with the filing date of the present application. Where applicable, the contents of any patent, patent application, or publication referred to in this application are incorporated herein by reference in their entirety and their equivalent family patents are also incorporated by reference, especially as they disclose definitions relating to synthetic techniques, products and process designs, polymers, comonomers, initiators or catalysts, and the like, in the art. To the extent that a definition of a particular term disclosed in the prior art is inconsistent with any definitions provided herein, the definition of the term provided herein controls.

The numerical ranges in this application are approximations, and thus may include values outside of the ranges unless otherwise specified. A numerical range includes all numbers from the lower value to the upper value, in increments of 1 unit, provided that there is a separation of at least 2 units between any lower value and any higher value. For example, if a compositional, physical, or other property (e.g., molecular weight, melt index, etc.) is recited as 100 to 1000, it is intended that all individual values, e.g., 100, 101, 102, etc., and all subranges, e.g., 100 to 166, 155 to 170, 198 to 200, etc., are explicitly recited. For ranges containing a numerical value less than 1 or containing a fraction greater than 1 (e.g., 1.1, 1.5, etc.), then 1 unit is considered appropriate to be 0.0001, 0.001, 0.01, or 0.1. For ranges containing single digit numbers less than 10 (e.g., 1 to 5), 1 unit is typically considered 0.1. these are merely specific examples of what is intended to be expressed and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application.

When used with respect to chemical compounds, the singular includes all isomeric forms and vice versa (e.g., "hexane" includes all isomers of hexane, individually or collectively) unless expressly specified otherwise. In addition, unless explicitly stated otherwise, the use of the terms "a", "an" or "the" are intended to include the plural forms thereof.

The terms "comprising," "including," "having," and derivatives thereof do not exclude the presence of any other component, step or procedure, and are not intended to exclude the presence of other elements, steps or procedures not expressly disclosed herein. To the extent that any doubt is eliminated, all compositions herein containing, including, or having the term "comprise" may contain any additional additive, adjuvant, or compound, unless expressly stated otherwise. Rather, the term "consisting essentially of … …" excludes any other components, steps or processes from the scope of any of the terms hereinafter recited, except those necessary for performance. The term "consisting of … …" does not include any components, steps or processes not specifically described or listed. Unless explicitly stated otherwise, the term "or" refers to the listed individual members or any combination thereof.

Definition of terms

GB6343-1995

National standards for the determination of the apparent (bulk) density of foams and rubbers

The present standard specifies the method of testing the apparent (bulk) density of foams and rubbers.

The standard is suitable for measuring the apparent total density and the apparent core density of the rigid foam plastic and the volume density of the semi-rigid and flexible foam plastic and the rubber.

GB8813-2008

National standard of rigid foam plastic compression strength test method

The present standard specifies a method for measuring the compressive strength of a rigid foam, its relative deformation, and the compressive stress and the compressive modulus of elasticity at a relative deformation of 10%.

GB8811-2008

National standard of rigid foam plastic dimensional stability test method

The present standard specifies a method for determining the dimensional stability of rigid foams under specific conditions of temperature and relative humidity.

The standard is suitable for measuring the dimensional stability of the rigid foam plastic.

GB/T 8624-2012

National standard for grading combustion performance of building materials and products

The present standards specify the nomenclature and definitions of construction materials and articles, fire performance ratings, fire performance rating criteria, fire performance rating designations and test reports.

The standard is suitable for grading and judging the combustion performance of building materials, decoration materials, products and the like used in building engineering.

The application provides a combined polyether, which comprises the following components in parts by mass: 70-90 parts of polyester polyol, 10-30 parts of polyether polyol, 2-3 parts of foam stabilizer, 1.5-3 parts of catalyst, 23-35 parts of flame retardant, 0.5-1 part of water and 15-31 parts of physical foaming agent. Wherein: a polyester polyol having a functionality of 2, a hydroxyl value of 170 to 240mgKOH/g, and a viscosity of 9000 to 13000mPa · s at 25 ℃; a polyether polyol having a hydroxyl value of 200 to 235mgKOH/g, a viscosity at 25 ℃ of 80000 to 120000mPa · s, and the sum of the mass parts of the polyether polyol and the polyol being 100 parts. The physical foaming agent comprises 10-16 parts of cyclopentane.

The foaming agent used by the composite polyether is an environment-friendly foaming agent, the Ozone Depletion Potential (ODP) of the prepared polyisocyanurate is 0, and the polyisocyanurate composite can be applied to environment-friendly high-flame-retardant PIR continuous boards.

On the other hand, in order to make up for the defects that a high-flame-retardant PIR plate prepared by a pure cyclopentane physical foaming agent system is poor in compression strength, oxygen index and dimensional stability and the like, the combined polyether reduces the mass percentage of the input amount of cyclopentane in the total input amount by 3-8 points, and a part of HFC-245fa is added, so that the produced continuous plate has excellent compression strength, dimensional stability and oxygen index. Meets the requirements of national standards GB6343-1995, GB8813-2008 and GB 8811-2008.

According to the high flame retardant PIR continuous plate prepared according to the embodiment of the application, the compression strength is more than 169KPa, the oxygen index is more than 30%, the dimensional change rate at high temperature of 100 ℃ and 24 hours is less than 0.68%, and the dimensional change rate at low temperature of-30 ℃ and 24 hours is less than 0.36%.

The selection and ratio of polyether polyol/polyester polyol directly affects the properties of polyisocyanurate foams, depending on the various properties of polyether polyol/polyester polyol, including but not limited to functionality, viscosity, etc.

According to the application, modified polyether polyol with flame retardant property is added in a combined polyether system and matched with polyester polyol according to a certain proportion, the proportion of flame retardant elements in the polyisocyanurate material is increased, and the flame retardant and the catalyst in the application are combined to prepare the polyisocyanurate building material which meets the national standard GB/T8624-2012.

In some embodiments, the water is preferably deionized water.

Examples

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. The reagents and raw materials used are commercially available unless otherwise specified. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.

In the following examples, the sources of the raw materials used are as follows:

polyester polyol PEB-175, available from Norway polyurethane, Inc., Shandong.

The flame-retardant polyether polyol RB-79 is purchased from Yabao chemical industry Co.

Foam stabilizer L-6620NT, available from Mitigo high and New materials group, USA.

The polyurethane composite catalyst N, N' -dimethylcyclohexylamine, K-15 and TMR-2 are purchased from air chemical industry Co.

The flame retardants TCPP and TEP are purchased from Yake chemical Co., Ltd.

Cyclopentane (CP), a physical blowing agent, available from Shanghai ocean chemical industries, Inc.

Physical blowing agent HFC-245fa, available from Honeywell.

Diphenylmethane diisocyanate, available from petunia, model PM 400.

In the following examples, the test criteria for each test item are as follows:

density detection Standard GB 6343-1995;

a compressive strength detection standard GB 8813-2008;

the dimensional stability detection standard GB 8811-2008;

the oxygen index detection standard GB 8624-2012.

Examples

In the following examples, polyisocyanurate continuous sheets were prepared by the following method:

(1) preparation of conjugate polyether

Pouring the components in the combined polyether into a container according to a specified proportion, and stirring at a rotating speed of 400-600 r/min for 0.8-1.2 h at 15-30 ℃ to mix uniformly.

(2) Preparation of polyisocyanurate continuous sheet

Adding isocyanate into a container in proportion, uniformly mixing the isocyanate with the composite polyether, uniformly coating the mixture on a steel plate preheated to 35-40 ℃, feeding the steel plate into a laminator at 55-70 ℃ for curing, and taking the cured steel plate out after curing for a period of time to obtain the environment-friendly high-flame-retardant PIR continuous plate. Wherein the mass ratio of the combined polyether to the isocyanate is 1: 1.5-2.5.

TABLE 1

Example 1:

the mass ratio of each component of the composite polyether of the present example is shown in table 1.

A preparation method of an environment-friendly high-flame-retardant PIR continuous board comprises the following steps:

(1) 70 parts of polyester polyol PEB-175, 30 parts of flame-retardant polyether polyol RB-79, 2.5 parts of foam stabilizer L-6620NT and a catalyst: 0.4 part of N, N' -dimethylcyclohexylamine, 1.5 parts of K-15, 0.6 part of TMR-2, 16 parts of cyclopentane CP as a physical foaming agent, 5 parts of HFC-245fa as the physical foaming agent, 1 part of water, 20 parts of TCPP as a flame retardant and 15 parts of TEP as a flame retardant are added into a stainless steel mixing kettle, the mixture is stirred for 1 hour at the rotating speed of 500 revolutions per minute at room temperature, and the composite polyether for the environment-friendly high-flame-retardant continuous plate is obtained by discharging;

(2) the method comprises the steps of accurately measuring and mixing materials by a high-pressure machine at the temperature of 22 ℃ according to the mass ratio of 1:2.5 of composite polyether for the environment-friendly high-flame-retardant continuous board to PM400 of isocyanate, coating the materials on a preheated (35-40 ℃) steel plate, curing the materials in a laminator (at the temperature of 55-70 ℃) for a period of time, and discharging the cured materials to obtain the environment-friendly high-flame-retardant PIR continuous board, wherein the physical properties of foams of the continuous board are shown in Table 2.

Example 2:

the compounding ratio of the components of the conjugate polyether of this example is shown in table 1.

(1) 80 parts of polyester polyol PEB-175, 20 parts of flame-retardant polyether polyol RB-79, 2.0 parts of foam stabilizer L-6620NT and catalyst: adding 0.5 part of N, N' -dimethylcyclohexylamine, 0.5 part of K-15, 0.5 part of TMR-2, 13 parts of cyclopentane CP (cyclic pentane) serving as a physical foaming agent, 10 parts of HFC-245fa serving as the physical foaming agent, 0.8 part of water, 20 parts of TCPP (flame retardant) and 10 parts of TEP (flame retardant) into a stainless steel mixing kettle, stirring at the room temperature at the rotating speed of 500 rpm for 1 hour, and discharging to obtain the environment-friendly high-flame-retardant composite polyether for the continuous plates;

(2) at the material temperature of 22 ℃, according to the mass ratio of 1:2 of the composite polyether for the environment-friendly high-flame-retardant continuous board to the isocyanate PM400, the materials are accurately metered and mixed by a high-pressure machine, coated on a preheated (35-40 ℃) steel plate, then enter a laminating machine (the temperature of the laminating machine is 55-70 ℃) for curing, and are discharged after curing for a period of time, so that the environment-friendly high-flame-retardant PIR continuous board is obtained, wherein the physical properties of foams of the continuous board are shown in Table 2.

Example 3:

(1) mixing 90 parts of polyester polyol PEB-175, 10 parts of flame-retardant polyether polyol RB-79, 2.0 parts of foam stabilizer L-6620NT and a catalyst: adding 0.4 part of N, N' -dimethylcyclohexylamine, 1.5 parts of K-15, 0.6 part of TMR-2, 10 parts of cyclopentane CP (cyclic pentane) serving as a physical foaming agent, 15 parts of HFC-245fa serving as a physical foaming agent, 0.5 part of water, 15 parts of TCPP (flame retardant) and 10 parts of TEP (flame retardant) into a stainless steel mixing kettle, stirring at the room temperature at the rotating speed of 500 rpm for 1 hour, and discharging to obtain the environment-friendly high-flame-retardant composite polyether for the continuous plates;

(2) the method comprises the steps of accurately measuring and mixing materials by a high-pressure machine at the temperature of 22 ℃ according to the mass ratio of 1:1.5 of composite polyether for the environment-friendly high-flame-retardant continuous board to PM400 of isocyanate, coating the materials on a preheated (35-40 ℃) steel plate, curing the materials in a laminator (at the temperature of 55-70 ℃) for a period of time, and discharging the cured materials to obtain the environment-friendly high-flame-retardant PIR continuous board, wherein the physical properties of foams of the continuous board are shown in Table 2.

Comparative example 1:

a preparation method of a PIR continuous plate comprises the following steps:

(1) 80 parts of polyester polyol PEB-175, 20 parts of flame-retardant polyether polyol RB-79, 2.5 parts of foam stabilizer L-6620NT and a catalyst: adding 0.5 part of N, N' -dimethylcyclohexylamine, 1.4 parts of K-15, 0.5 part of TMR-2, 20 parts of cyclopentane CP as a physical foaming agent, 0.8 part of water, 15 parts of TCPP (flame retardant) and 10 parts of TEP (flame retardant) into a stainless steel mixing kettle, stirring at the rotating speed of 500 revolutions per minute for 1 hour at room temperature, and discharging to obtain the composite polyether for the environment-friendly high-flame-retardant continuous plate;

(2) at the material temperature of 22 ℃, according to the mass ratio of 1:2 of the composite polyether for the environment-friendly high-flame-retardant continuous board to the isocyanate PM400, the materials are accurately metered and mixed by a high-pressure machine, coated on a preheated (35-40 ℃) steel plate, then enter a laminating machine (the temperature of the laminating machine is 55-70 ℃) for curing, and are taken out after curing for a period of time, so that the PIR continuous board is obtained, wherein the physical properties of foams of the continuous board are shown in Table 2.

Effects of the embodiment

The polyisocyanurate foams prepared in examples 1-3 and comparative example 1 were subjected to an effect test, and the test results are shown in table 2 below.

As can be seen from table 2, the high flame retardant PIR continuous sheet prepared according to the embodiment of the present invention has a compressive strength of 169KPa or more, an oxygen index of 30% or more, a dimensional change rate at 100 ℃ and 24 hours at a high temperature of less than 0.68%, and a dimensional change rate at-30 ℃ and 24 hours at a low temperature of less than 0.36%.

Referring to table 1, in comparative example 1, the input amount of cyclopentane is 20 parts, and the mass percentage of the input amount is 13.3%. In example 2, the amount of cyclopentane charged was 13 parts and 8.8% by mass of the total amount charged, which was reduced by 4.5 points compared to comparative example 1, and 10 parts of HFC-245fa was added. The PIR continuous sheet produced based on example 2 has more excellent compressive strength, dimensional stability and oxygen index than the sheet produced in comparative example 1.

The raw materials used in the application are all commercially available raw materials, are wide in source and can be produced in a large scale.

TABLE 2

The embodiments described above are intended to facilitate the understanding and appreciation of the application by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present application is not limited to the embodiments herein, and those skilled in the art who have the benefit of this disclosure will appreciate that many modifications and variations are possible within the scope of the present application without departing from the scope and spirit of the present application.

Claims

1. The polyisocyanurate continuous plate is characterized by comprising combined polyether and isocyanate in a mass ratio of 1: 1.5-2.5;

the combined polyether comprises the following components in parts by weight: 70-90 parts of polyester polyol, 10-30 parts of polyether polyol, 2-3 parts of foam stabilizer, 1.5-3 parts of catalyst, 23-35 parts of flame retardant, 0.5-1 part of water and 15-31 parts of physical foaming agent, wherein:

the sum of the mass parts of the polyester polyol and the polyether polyol is 100 parts;

the polyester polyol is PEB-175, the functionality of the polyester polyol is 2, the hydroxyl value of the polyester polyol is 170-240 mgKOH/g, and the viscosity of the polyester polyol at 25 ℃ is 9000-13000 mPa & s;

the polyether polyol is RB-79, the hydroxyl value of the polyether polyol is 200-235 mgKOH/g, and the viscosity at 25 ℃ is 80000-120000 mPa & s; and

the physical foaming agent comprises 5-15 parts of HFC-245fa and 10-16 parts of cyclopentane;

the foam stabilizer is L-6620 NT;

the isocyanate is diphenylmethane diisocyanate and has the model number of PM 400.

2. The polyisocyanurate continuous sheet of claim 1, wherein the flame retardant comprises one or more of tris (2-chloropropyl) phosphate, tris (2-chloroethyl) phosphate, and dimethyl methylphosphonate.

3. The polyisocyanurate continuous sheet of claim 1, wherein the HFC-245fa has a molecular weight of 134g/mol and a boiling point of 15 ℃.

4. The polyisocyanurate continuous sheet according to claim 1, wherein the catalyst is an amine catalyst or an organometallic catalyst comprising one or more of N, N' -dimethylcyclohexylamine, potassium isooctanoate K-15, quaternary ammonium salt catalyst TMR-2.

5. The polyisocyanurate continuous sheet according to claim 4, wherein the catalyst is a composite catalyst comprising N, N '-dimethylcyclohexylamine, potassium isooctanoate K-15, quaternary ammonium salt catalyst TMR-2, wherein the mass ratio of the N, N' -dimethylcyclohexylamine, the potassium isooctanoate K-15 and the quaternary ammonium salt catalyst TMR-2 is 1: 2-3: 1 to 2.

6. The polyisocyanurate continuous sheet according to claim 1, wherein the method for producing the conjugate polyether comprises: pouring the components of the combined polyether as defined in any one of claims 1-5 into a container and mixing uniformly.

7. The polyisocyanurate continuous sheet according to claim 6, wherein the production method comprises: pouring the components of the combined polyether into a container and uniformly mixing the components of the combined polyether, wherein the step of stirring the components of the combined polyether at the temperature of 15-30 ℃ at the rotating speed of 400-600 r/min for 0.8-1.2 h.

8. A method of making a polyisocyanurate continuous sheet comprising the steps of:

pouring the components of the combined polyether as defined in any one of claims 1-5 into a container and mixing uniformly; and

and adding isocyanate into the container in proportion, uniformly mixing the isocyanate with the combined polyether, uniformly coating the mixture on a steel plate preheated to a set temperature, and feeding the steel plate into a laminating machine for curing to obtain the polyisocyanurate continuous plate.

9. The method according to claim 8, wherein the set temperature of the steel sheet is in a range of 35 to 40 ℃.