Halogen-free flame-retardant polyether polyol for rigid polyurethane foam thermal insulation material and preparation method of halogen-free flame-retardant polyether polyol

Abstract

The invention discloses a halogen-free flame-retardant polyether polyol for a rigid polyurethane foam thermal insulation material and a preparation method of the halogen-free flame-retardant polyether polyol, through improvement and innovation of the halogen-free flame-retardant polyether polyol, an original flammable material is changed into a non-flammable material, and under the condition that the product efficiency is not reduced, the flame-retardant polyether polyol can be used as a flame-retardant flame-retardant polyether polyol for a rigid polyurethane foam thermal insulation material. In addition, the smoke density of the halogen-free flame-retardant polyether polyol provided by the invention is greatly reduced, the smoke density in a fire disaster can be reduced, safety guarantee and a safety foundation are provided for personnel, and the halogen-free flame-retardant polyether polyol has a wide market application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal insulation materials, and particularly to a halogen-free flame-retardant polyether polyol for rigid polyurethane foam thermal insulation materials and a preparation method thereof. Background Art

[0002] Rigid polyurethane foam (RPUF) is an organic polymer material formed by the esterification reaction of a polyol with a branched structure and an isocyanate, and its main chain contains repeating urethane groups. The product has a closed-cell structure and a thermal conductivity of only 0.020 - 0.030 W / (m·K), with excellent thermal insulation performance far exceeding other thermal insulation materials. It also has high compressive strength, light weight, and easy processing, and is widely used in fields such as building exterior wall insulation, pipeline insulation, and refrigerator and freezer insulation. Compared with traditional thermal insulation materials (such as concrete, wood, and glass fiber), RPUF has more excellent thermal insulation performance. The thermal insulation performance of 50 mm thick rigid polyurethane foam is equivalent to that of 1720 mm thick bricks, 200 mm thick wood, and 800 mm thick polystyrene. However, RPUF is a highly flammable substance. As the application scope of RPUF continues to expand, it is urgent to carry out flame-retardant modification on it.

[0003] Divided by flame-retardant elements, the flame retardancy of RPUF is divided into halogen-based flame retardancy and halogen-free flame retardancy. Currently, the widely used one on the market is halogen-based (especially bromine-based) flame retardancy, which releases hydrogen halide corrosive gases and toxic carcinogenic substances during combustion, endangering the environment and human health. Therefore, halogen-free flame retardancy is an inevitable way for the sustainable development of RPUF flame retardancy.

[0004] Divided by flame-retardant methods, the flame retardancy of RPUF is divided into additive flame retardancy and reactive flame retardancy. Due to its simple operation and low price, the currently widely used one on the market is additive flame retardancy, that is, directly adding a flame retardant to the polyurethane foam material. However, additive flame retardancy has problems such as low flame-retardant efficiency, non-persistent flame-retardant effect, and easy precipitation of the flame retardant. Reactive flame retardancy refers to an organic compound containing flame-retardant elements or flame-retardant groups such as phosphorus, nitrogen, and silicon and having active functional groups. The active functional groups react with polyurethane raw materials and are combined into the polyurethane macromolecular chain in the form of chemical bonds. Therefore, it not only has high flame-retardant efficiency but also avoids problems such as non-persistent flame-retardant effect and precipitation of the flame retardant. Summary of the Invention

[0005] The purpose of the present invention is to provide a halogen-free flame-retardant polyether polyol for rigid polyurethane foam thermal insulation materials and a preparation method thereof to solve the problems raised in the above background art.

[0006] To achieve the above purpose, the present invention provides the following solution: A halogen-free flame-retardant polyether polyol for rigid polyurethane foam thermal insulation materials, and the molecular formula of this polyether polyol is as follows:

[0007] Preferably, the polyether polyol is in powder form and is obtained by precipitating the intermediate product in ionic water. After obtaining the white flocculent substance, the white flocculent substance is dried under vacuum at 80 - 120 o °C.

[0008] Preferably, the intermediate product is obtained by adding a phosphorus-based flame retardant initiator to propylene oxide and carrying out a ring-opening polymerization reaction under the action of a catalyst.

[0009] Preferably, the catalyst is triethanolamine or diethanol, and the environmental temperature for the ring-opening polymerization reaction is 40 - 60 o °C.

[0010] Preferably, the phosphorus-based flame retardant initiator is obtained by reacting a phosphorus-containing intermediate with acrylic acid and then processing.

[0011] Preferably, the preparation method of the halogen-free flame-retardant polyether polyol for rigid polyurethane foam thermal insulation materials is as follows: a. Add a phosphorus-based flame retardant initiator to propylene oxide and use a catalyst; b. Control the environmental temperature of step a at 40 - 60 o °C to carry out a ring-opening polymerization reaction to obtain a milky white gel; c. Add the milky white gel obtained in step b to deionized water for precipitation to obtain a white flocculent substance; d. Vacuum-dry the white flocculent substance at 80 - 120 o °C to obtain a white powder, which is the halogen-free flame-retardant polyether polyol; Preferably, the molar ratio of the above-mentioned phosphorus-based flame retardant initiator to propylene oxide and the catalyst is 1:0.8 - 1.2:0.0008 - 0.0012.

[0012] The preparation method of the phosphorus-based flame retardant initiator is as follows: e. Carry out a reflux reaction on the phosphorus-containing intermediate and acrylic acid at 70 - 90 °C; f. Control the reaction time at 4 - 8 h to obtain a light yellow transparent mixed solution; g. Add a ferrous bromide catalyst to the mixed solution obtained in step f, carry out an alternate vacuum pumping and nitrogen filling operation, and circulate 3 - 5 times to remove oxygen; h. After step g is completed, add an ethyl 2-bromopropionate initiator, control the environmental temperature at 40 - 60 o °C, and then initiate an atom transfer radical polymerization reaction to obtain a milky white viscous substance; i. Vacuum-dry the milky white viscous substance at 80 - 120 oThe C is vacuum dried to obtain a white powder, and thus the phosphorus-based flame retardant initiator can be obtained.

[0013] Preferably, the phosphorus-containing intermediate is diphenylphosphine-6-oxide, and its molecular formula is C 12 H9O2P, with a molecular weight of 216.

[0014] Preferably, the molar ratio of the phosphorus-containing intermediate, acrylic acid, ferrous bromide, and ethyl 2-bromopropionate is 1:0.8 - 1.2:0.002 - 0.06:0.0008 - 0.0012.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention makes the originally flammable polyurethane foam into a flame-retardant material, and at the same time has excellent flame-retardant performance. Its smoke density has been greatly reduced, providing a guarantee for reducing the asphyxiation death of people in fires. Detailed implementation manners

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0017] Example 1 e. The phosphorus-containing intermediate and acrylic acid are refluxed at 70 o °C. f. Control the reaction time to be 4 to obtain a light yellow transparent mixture; g. Add a ferrous bromide catalyst to the mixture obtained in step f, perform alternate vacuum pumping and nitrogen filling operations, and cycle 3 times to remove oxygen; h. After step g is completed, add an ethyl 2-bromopropionate initiator, control the ambient temperature at 40 o °C, and then initiate an atom transfer radical polymerization reaction to obtain a milky white viscous substance; i. The milky white viscous substance is vacuum dried at 80 o °C to obtain a white powder, and thus the phosphorus-based flame retardant initiator can be obtained.

[0018] In this embodiment, to prepare the phosphorus-based flame retardant initiator, the molar ratio of the phosphorus-containing intermediate, acrylic acid, ferrous bromide, and ethyl 2-bromopropionate is 1:0.8:0.002:0.0008.

[0019] a. Add the phosphorus-based flame retardant initiator to propylene oxide and use a catalyst; b. Control the ambient temperature of step a at 40 oC undergoes ring-opening polymerization reaction to obtain a milky white jelly; c. Add the milky white jelly obtained in step b to deionized water for precipitation to obtain a white floc; d. Vacuum dry the white floc at 80 o °C to obtain a white powder, which is the halogen-free flame retardant polyether polyol; In this example, the molar ratio of the phosphorus-based flame retardant initiator to propylene oxide and the catalyst is 1:0.8:0.0008.

[0020] The halogen-free flame retardant polyether polyol obtained through the above reactions has a number average molecular weight of 5800 mol / kg, a hydroxyl value of 520 mg KOH / g, and a phosphorus content of 3.9%.

[0021] Using deionized water as the catalyst, the synthesis of the rigid polyurethane foam from Example 1 and isocyanate is denoted as flame retardant RPUF-1, and its flame retardancy, smoke suppression performance, mechanical properties, and thermal insulation performance are tested through the limiting oxygen index, smoke density, compressive strength, and thermal conductivity.

[0022] Among them, the limiting oxygen index value of the sample is tested according to the GB2406-80 standard, the smoke density value of the sample is tested according to the GB / T8627, the compressive strength of the sample is tested according to the GB T 8813-2008 standard, and the thermal conductivity of the sample is tested according to the GB10294-88 standard.

[0023] For the rigid polyurethane foam material using Example 1 as the halogen-free reactive flame retardant, its limiting oxygen index is 29%, the smoke density is 78 mg / L, the compressive strength is 448 kPa, and the thermal conductivity is 0.020 W·m -1 ·K -1 .

[0024] Example Two e. Reflux react the phosphorus-containing intermediate and acrylic acid at 80 o °C; f. Control the reaction time at 6 h to obtain a light yellow transparent mixture; g. Add a ferrous bromide catalyst to the mixture obtained in step f, perform alternate vacuum pumping and nitrogen filling operations, and cycle 4 times to remove oxygen; h. After step g is completed, add an ethyl 2-bromopropionate initiator, control the ambient temperature at 50 o °C, and then initiate an atom transfer radical polymerization reaction to obtain a milky white viscous substance; i. Vacuum dry the milky white viscous substance at 100 o °C to obtain a white powder, which is the phosphorus-based flame retardant initiator; The molar ratio of the phosphorus-containing intermediate mentioned in step e-i to acrylic acid, ferrous bromide, and ethyl 2-bromopropionate is 1:1:0.004:0.001.

[0025] a. Add a phosphorus-based flame retardant initiator to propylene oxide and use a catalyst. b. Control the environmental temperature of step a at 50 o C to carry out a ring-opening polymerization reaction to obtain a milky white gel. c. Add the milky white gel obtained in step b to deionized water for precipitation to obtain white flocculants. d. Vacuum dry the white flocculants at 100 o C to obtain a white powder, which is a halogen-free flame retardant polyether polyol. In Example 2, the molar ratio of the above phosphorus-based flame retardant initiator to propylene oxide and the catalyst is 1:1:0.001.

[0026] The finally obtained halogen-free flame retardant polyether polyol has a number average molecular weight of 8400 mol / kg, a hydroxyl value of 550 mgKOH / g, and a phosphorus content of 4.3%.

[0027] Using deionized water as a catalyst, Example 2 is synthesized with isocyanate to prepare a rigid polyurethane foam (denoted as flame retardant RPUF-2), and its flame retardant performance, smoke suppression performance, mechanical properties, and heat preservation performance are tested through the limiting oxygen index, smoke density, compressive strength, and thermal conductivity.

[0028] Among them, the limiting oxygen index value of the sample is tested according to the GB2406-80 standard, the smoke density value of the sample is tested according to the GB / T8627, the compressive strength of the sample is tested according to the GB T 8813-2008 standard, and the thermal conductivity of the sample is tested according to the GB10294-88 standard.

[0029] For the rigid polyurethane foam material using Example 2 as a halogen-free reactive flame retardant, its limiting oxygen index is 35%, the smoke density is 65 mg / L, the compressive strength is 450 kPa, and the thermal conductivity is 0.013 W·m -1 ·K -1 .

[0030] Example 3 The halogen-free flame retardant polyether polyol for rigid polyurethane foam thermal insulation materials is prepared by the following method: e. Carry out a reflux reaction on the phosphorus-containing intermediate and acrylic acid at 90 o C. f. Control the reaction time at 8 h to obtain a light yellow transparent mixed solution. g. Add ferrous bromide catalyst to the mixed solution obtained in step f, perform alternate vacuum pumping and nitrogen filling operations, and cycle 5 times to remove oxygen; h. After step g is completed, add ethyl 2-bromopropionate initiator, and control the ambient temperature at 60 o °C, and then initiate an atom transfer radical polymerization reaction to obtain a milky viscous substance; i. Vacuum dry the milky viscous substance at 120 o °C to obtain a white powder, which is the phosphorus-based flame retardant initiator.

[0031] In this example, the molar ratio of the phosphorus-containing intermediate to acrylic acid, ferrous bromide, and ethyl 2-bromopropionate is 1:1.2:0.06:0.0012.

[0032] a. Add the phosphorus-based flame retardant initiator to propylene oxide and use a catalyst; b. Control the ambient temperature of step a at 60 o °C to carry out a ring-opening polymerization reaction to obtain a milky gel; c. Add the milky gel obtained in step b to deionized water for precipitation to obtain a white floc; d. Vacuum dry the white floc at 120 o °C to obtain a white powder, which is the halogen-free flame retardant polyether polyol; In this example, the molar ratio of the phosphorus-based flame retardant initiator to propylene oxide and the catalyst is 1:1.2:0.0012.

[0033] The finally obtained halogen-free flame retardant polyether polyol has a number average molecular weight of 13500 mol / kg, a hydroxyl value of 610 mgKOH / g, and a phosphorus content of 5.3%.

[0034] Using deionized water as a catalyst, synthesize and prepare rigid polyurethane foam (denoted as flame retardant RPUF-3) from Example 3 and isocyanate, and test its flame retardancy, smoke suppression performance, mechanical properties, and thermal insulation performance through the limiting oxygen index, smoke density, compressive strength, and thermal conductivity.

[0035] Among them, the limiting oxygen index value of the sample is tested according to the GB2406-80 standard, the smoke density value of the sample is tested according to the GB / T8627, the compressive strength of the sample is tested according to the GB T 8813-2008 standard, and the thermal conductivity of the sample is tested according to the GB10294-88 standard.

[0036] For the rigid polyurethane foam material using Example 3 as a halogen-free reactive flame retardant, its limiting oxygen index is 32%, the smoke density is 86 mg / L, the compressive strength is 420 kPa, and the thermal conductivity is 0.028 W·m -1 ·K -1。

[0037] In various embodiments of the present invention, the chemical reaction equations involved in steps e-i are as follows:

[0038] In various embodiments of the present invention, the chemical reaction equations involved in steps a-d are as follows:

[0039] A comparison was made with the rigid polyurethane foam materials (denoted as RPUF) used for building facades synthesized from polyether polyols prepared from commercially available glycerol and propylene oxide and isocyanates, as shown in the following table:

[0040] The rigid polyurethane foam materials prepared using the halogen-free flame-retardant polyether polyols prepared in Examples 1-3 as reactive flame retardants all have excellent flame-retardant properties, making the originally flammable (limiting oxygen index < 22%) polyurethane foam into a flame-retardant (limiting oxygen index > 27%) material. At the same time, the smoke density has been greatly reduced, providing protection for reducing the suffocation deaths of people in fires; moreover, the compressive strength and thermal conductivity of the polyurethane foam material after flame-retardant modification are comparable to those of the unmodified material, and the flame-retardant modification does not damage the mechanical properties and thermal insulation properties of the polyurethane foam material; in particular, for the polyurethane foam material RPUF-2 modified by flame retardancy in Example 2, while having a high oxygen index, low smoke density, and high compressive strength, it also has a very low thermal conductivity.

[0041] It can be seen that the halogen-free flame-retardant polyether polyol prepared by the present invention is particularly suitable as a thermal insulation and fireproof material for the building exterior.

[0042] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A halogen-free flame-retardant polyether polyol for rigid polyurethane foam thermal insulation materials, characterized in that, The molecular formula of the polyether polyol is as follows:

2. The halogen-free flame-retardant polyether polyol for rigid polyurethane foam thermal insulation material according to claim 1, wherein: The polyether polyol is in powder form. It is precipitated from an intermediate product in ionic water. After obtaining white flocculates, the white flocculates are dried under vacuum at 80 - 120 o °C to obtain the product.

3. The halogen-free flame-retardant polyether polyol for rigid polyurethane foam thermal insulation material according to claim 2, characterized in that: The intermediate product is prepared by adding a phosphorus-based flame retardant initiator into propylene oxide and carrying out a ring-opening polymerization reaction under the action of a catalyst.

4. The halogen-free flame-retardant polyether polyol for rigid polyurethane foam thermal insulation material according to claim 3, wherein: The catalyst is triethanolamine or diethanol, and the environmental temperature for the ring-opening polymerization reaction is 40 - 60 o °C.

5. The halogen-free flame-retardant polyether polyol for rigid polyurethane foam thermal insulation material according to claim 3, characterized in that: The phosphorus-based flame retardant initiator is prepared by reacting a phosphorus-containing intermediate with acrylic acid and then processing.

6. The preparation method of the halogen-free flame-retardant polyether polyol for rigid polyurethane foam thermal insulation materials as described in any one of claims 1-5 is as follows: a. Add a phosphorus-based flame retardant initiator into propylene oxide and use a catalyst; b. Control the environmental temperature in step a to 40 - 60 o C performs a ring-opening polymerization reaction to obtain a milky white gel; c. Add the milky white colloid obtained in step b into deionized water for precipitation to obtain white floccules; d. Vacuum dry the white flocculent substance at 80 - 120 o °C to obtain a white powder, which is the halogen-free flame-retardant polyether polyol.

7. The preparation method of the halogen-free flame-retardant polyether polyol for rigid polyurethane foam thermal insulation material according to claim 6, characterized in that: The molar ratio of the above-mentioned phosphorus-based flame retardant initiator to propylene oxide and the catalyst is 1:0.8-1.2:0.0008-0.0012.

8. The preparation method of the halogen-free flame retardant polyether polyol for rigid polyurethane foam thermal insulation material according to claim 7, characterized in that, The preparation method of the phosphorus-based flame retardant initiator is as follows: e. React the phosphorus-containing intermediate and acrylic acid under reflux at 70-90 o °C; f. Control the reaction time at 4-8 h to obtain a light yellow transparent mixed solution; g. Add a ferrous bromide catalyst into the mixed solution obtained in step f, carry out an alternating vacuum and nitrogen filling operation, and cycle 3-5 times to remove oxygen; h. After step g is completed, ethyl 2-bromopropionate initiator is added, and the environmental temperature is controlled at 40-60 o °C, thereby initiating an atom transfer radical polymerization reaction to obtain a milky viscous substance; i. Vacuum dry the milky viscous substance at 80 - 120 o °C to obtain a white powder, which is the phosphorus-based flame retardant initiator.

9. The preparation method of the halogen-free flame-retardant polyether polyol for rigid polyurethane foam thermal insulation material according to claim 8, characterized in that, The phosphorus-containing intermediate is diphenylphosphine-6-oxide, with the molecular formula C 12 H9O2P and a molecular weight of 216.

10. The preparation method of the halogen-free flame-retardant polyether polyol for rigid polyurethane foam thermal insulation material according to claim 9, characterized in that, The molar ratio of the phosphorus-containing intermediate to acrylic acid, ferrous bromide, and ethyl 2-bromopropionate is 1:0.8-1.2:0.002-0.06:0.0008-0.0012.

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