Pouring preparation method of high-strength rigid polyurethane foam plastic

Abstract

The invention discloses a pouring preparation method of a high-strength rigid polyurethane foam plastic, which comprises the following steps: selecting commercial dendritic polyester polyol with wide sources, and simultaneously, liquefying powder dendritic polyol solid before foaming reaction by selecting a catalyst, so as to obtain the high-strength rigid polyurethane foam plastic. On one hand, the risk that a metering pump is blocked or abraded is avoided, on the other hand, the high-strength rigid polyurethane foam can be used as a rear-section catalyst in the polyurethane foaming process, purification is not needed, and the high-strength rigid polyurethane foam with excellent comprehensive performance is efficiently prepared.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyurethane materials, and particularly relates to a casting preparation method of high-strength rigid polyurethane foam plastic. BACKGROUND

[0002] Foamed polyurethane materials have the advantages of low density, light weight, low thermal conductivity, good cushioning, sound absorption and heat insulation, and are widely used in the fields of transportation industry, packaging and building industry, sports goods and shoe materials. However, the conventional polyurethane foam material has insufficient bearing capacity and cannot adapt to high load working conditions.

[0003] Conventional structural reinforcement mostly uses linear polymers as the main material. This is generally achieved by using polyether (or polyester) polyols with high functionality, high hydroxyl value and low molecular weight to react with polyisocyanate. The obtained foam plastic has a large number of network structures in the molecule (i.e. a large number of crosslinking points and high density), high hardness, high compressive strength, good dimensional stability and good temperature resistance. Crosslinking polyols usually have high viscosity, which significantly increases the viscosity of the polyol combination, making it difficult to mix with low-viscosity isocyanate uniformly, resulting in uneven rigid foam, affecting the apparent quality of the foam product, and the high-viscosity polyol combination cannot meet the extraction and atomization requirements of the foaming equipment, and cannot meet the process requirements in large-scale industrial production. At the same time, increasing the intrinsic crosslinking degree of the material often leads to an increase in the brittleness of the material system, a decrease in the bending performance and impact resistance, and difficulty in meeting the actual use requirements. Therefore, the conventional polyurethane material using linear polymers as the main body has a difficult-to-reconcile contradiction between the mechanical properties and the foaming process, and it is necessary to develop new material structure design ideas for polyurethane materials to achieve balanced development of the mechanical properties and the process properties.

[0004] In the field of high molecular polymers, compared with general linear polymers, highly branched polymer molecules have a three-dimensional spatial topological structure and a large number of active functional groups, which can give the material excellent strength and special functionality. As one of the highly branched polymers, the special dendritic structure of the dendritic polymer makes it have the characteristics of low viscosity, non-crystallization, high solubility, a large number of end group functional groups and large free volume. However, the dendritic structure is difficult to control, and the dendritic structure is complex and difficult to analyze. CN 109851836 B synthesizes a hyperbranched polyester polyol solid with dimeric glycerol as the core through a complex three-step reaction, and prepares high-strength polyurethane foam by using it as a crosslinking agent. The reaction time of the hyperbranched polyester polyol is more than 10 hours, the reaction conditions are complex and low in efficiency, and the patent does not mention how to purify the introduced PTSA catalyst, and a small amount of catalyst may have a great influence on the foaming parameters and foam performance of the foam. In addition, the hyperbranched polyester polyol solid is easy to cause blockage or wear of the metering pump in the foaming equipment, which is not conducive to the long-term use of the foaming equipment, and at the same time, the crosslinking degree of the foam body is limited, and the strength improvement is not obvious. CN 118852594 A synthesizes a hyperbranched polyester polyol through a complex three-step reaction, and at the same time, at least two catalysts are introduced in the reaction process, among which the second catalyst is not a polyurethane foaming catalyst, and the patent does not mention how to purify it. CN 104610528 B synthesizes a hyperbranched polyurethane polyol through a complex two-step method, and uses it to prepare rigid polyurethane foam.

[0005] In summary, in order to solve one or more of the above problems, a commercially available dendritic polyester polyol with a wide source is selected, and at the same time, a catalyst is selected, so that the powder dendritic polyol solid is liquefied before the foaming reaction, on the one hand, avoiding the risk of blockage or wear of the metering pump, on the other hand, it can also be used as a post-catalyst in the polyurethane foaming process without purification, and a high-strength, high-toughness, impact-resistant rigid polyurethane foam with excellent comprehensive performance is efficiently prepared. SUMMARY

[0006] In view of the above defects of the prior art, the present application aims to improve the load-bearing capacity of polyurethane foam materials and efficiently prepare a high-strength, high-toughness, impact-resistant rigid polyurethane foam with excellent comprehensive performance. In order to achieve the above-mentioned purpose, the present application provides a high-strength, high-toughness, impact-resistant rigid polyurethane foam material and a preparation method thereof, which effectively improves the compressive strength of the polyurethane foam material and improves the comprehensive performance of the foam, and can be applied to the heat insulation scene with high load working conditions.

[0007] The technical scheme of the present application: The high-strength, high-toughness, impact-resistant rigid polyurethane foam plastic according to the present application is made from raw materials including the following weight parts: Commercial polyester polyol 100 parts; Dendritic polyester polyol 10-40 parts; Post-stage catalyst 0.1-0.3 parts; Pre-stage catalyst 0.1-0.3 parts; Foam stabilizer 1-3 parts; Crosslinking agent 5-15 parts; Foaming agent 0.5-20 parts; Flame retardant 5-15 parts; Polyisocyanate 100-150 parts.

[0008] Further, the commercial polyester polyol includes one or more of 3152, 2452, 2412, 3302, etc. phthalic anhydride polyester polyol, with a hydroxyl value of 200-350 mgKOH / g and a viscosity of 1000 mpa·s to 8000 mpa·s.

[0009] Further, the dendritic polyester polyol includes one or more of CYD H10, CYD H20, CYD H30, CYD H40. The dendritic polyester polyol has a number of terminal hydroxyl groups of 8-64, a molecular weight of 500-7300 g / mol, and a hydroxyl value of 670-530 mg KOH / g.

[0010] Further, the post-stage catalyst is one or both of T-9 (stannous octoate) and T-12 (dibutyltin dilaurate).

[0011] Further, the pre-stage catalyst is PC-5 (pentamethyldiethylenetriamine).

[0012] Further, the foam stabilizer is one or more of M-8805, M-8808, M-8809, M-8815, M-8860, M-88308, M-88310, M-88108, M-88109, M-88716, M-88719; Further, the crosslinking agent is one or more of glycerol, pentaerythritol, sorbitol, sucrose, polyether 403; Further, the foaming agent includes one or both of a physical foaming agent and a chemical foaming agent, wherein the physical foaming agent is one or more of HFC-245fa, HFC-134a, HFC-365mfc, HFC-227ea, HCFC-141b, methyl formate, cyclopentane, n-pentane, cycloisopentane, 3,3-trifluoropropene; and the chemical foaming agent is water.

[0013] Further, the flame retardant is one or more of TCPP, TCEP, and TEP; Further, the -NCO content of the polyisocyanate is 30% to 35%, the functionality is 2.5 to 2.9, the viscosity is 150 to 250 mPa s, and the density is 1.20 to 1.30 g cm -3 .

[0014] The pouring preparation method of the high-strength rigid polyurethane foam plastic comprises the following steps: A. The raw materials of the high-strength, high-toughness and impact-resistant rigid polyurethane foam plastic are weighed according to the weight parts respectively; B. The commercial polyester polyol is added to a reaction bottle, and a post-stage catalyst is added. The temperature is raised to 190-220 DEG C. The dendritic polyol is gradually added to the reaction bottle in 3-4 times. After 2-3 hours of reaction, the dendritic polyol is completely dissolved.

[0015] C. The mixture obtained in step B, a foam stabilizer, a crosslinking agent, a foaming agent, a flame retardant and a pre-stage catalyst are stirred at a speed of 800-2000 rpm to obtain a component A; D. The polyisocyanate (component B) is quickly added to the polyol combination, and stirred at 25-35 DEG C to obtain a PU slurry; E. The PU slurry is quickly injected into a preheated mold for foaming, and then the mold (50 cm wide * 150 cm high * 2 cm) is treated at 60-120 DEG C, and cooled to room temperature to obtain the rigid polyurethane foam plastic.

[0016] Compared with the prior art, the present application has the following beneficial effects: (1) The liquefaction of the dendritic polyol powder improves the material physical and chemical properties In the CN 115181240 A invention patent, the powder hydroxyl-terminated hyperbranched polyester HyPer H30 is directly used for foaming. On the one hand, the powder in the combination material is easy to cause blockage or wear of the metering pump in the foaming equipment, which is not conducive to the long-term use of the foaming equipment. On the other hand, since the powder is not liquefied, only the end hydroxyl groups of the dendritic polyol molecules on the surface of the powder can participate in the reaction, and the end hydroxyl groups of the dendritic polyol molecules in the powder cannot participate in the reaction, resulting in limited crosslinking degree of the foam and unobvious strength improvement. In the present application, the powder dendritic polyol solid is liquefied in advance before the foaming reaction by carefully selecting the catalyst. On the one hand, the risk of blockage or wear of the metering pump is avoided. On the other hand, the liquefied powder can also be used as a post-stage catalyst in the polyurethane foaming process. The carefully selected multipurpose catalyst avoids the introduction of impurities in the polyol combination material, and ensures the full play of the performance of the combination material.

[0017] (2) The role of dendritic polyester polyol The hyperbranched polyester amide polyol has a three-dimensional spatial topological structure and a large number of active functional groups, and can endow the material with excellent strength and special functionality, and the special branched structure makes the polyol have the characteristics of low viscosity, a large number of end group functional groups, a large free volume, non-crystallization, high solubility and the like.

[0018] The hyperbranched structure significantly increases the crosslinking density of the polyurethane foam by a large number of end group functional groups on the polyol, and simultaneously improves the compression strength, wear resistance and temperature resistance; the free volume introduced by the hyperbranched structure improves the toughness and impact resistance of the material, and solves the contradiction that the high-strength material is easy to be brittle.

[0019] (3) Cost and process advantages The preparation process of the high-strength, high-toughness and impact-resistant rigid polyurethane foam plastic provided by the application realizes the liquefaction of the powder dendritic polyol molecules by adopting a simple one-step ester exchange reaction, the catalyst does not need to be removed after the reaction, the time for post-treatment is saved, and the reaction condition is simple. Meanwhile, the raw materials are commercialized, have a wide source and low cost, have certain advantages in time consumption and cost, and are easy to be prepared in large scale. BRIEF DESCRIPTION OF DRAWINGS

[0020] Other features, objects and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments with reference to the attached drawings: Figure 1 The compression strength comparison chart of the rigid polyurethane foam prepared for example 1, example 2, comparative example 1 and comparative example 2 of the application. DETAILED DESCRIPTION

[0021] The specific embodiments of the application are further described below with reference to the technical solutions.

[0022] The following are various exemplary embodiments of the application, which should not be considered as limiting the application, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the application. It should be understood that the terms described in the application are only for describing the specific embodiments, and are not used to limit the application.

[0023] In addition, for the numerical range in the application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value in the stated range, and any other stated value or intermediate value in the stated range, is also included in the application. The upper limit and the lower limit of these smaller ranges can be independently included or excluded from the range.

[0024] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0025] The terms "comprising," "including," "having," "containing," etc., used in this document are open-ended, meaning they include but are not limited to. The synthesis method used in this invention is a conventional synthesis method in the art, and the composition and structure of the product can be deduced from the raw materials used. Detailed Implementation Method 1 A. Weigh the raw materials of the high-strength, high-toughness, and impact-resistant rigid polyurethane foam according to the following weight proportions; Phthalic anhydride polyester polyol (3152) 100 parts; Dendritic polyester polyol (CYD H2O) 20 parts; Catalyst (T-9) 0.2 parts; Catalyst (PC-5) 0.2 parts Foam stabilizer (M-8805) 1.5 parts; Crosslinking agent (polyether 403) 10 parts, triethanolamine 2 parts; Foaming agent (HCFC-141b 3 parts, methyl formate 4 parts); 10 parts flame retardant (TCEP); 150 parts of polyisocyanate (PM200).

[0027] B. Add phthalic anhydride polyester polyol (3152) to the reaction flask, add catalyst (T-9), heat to 200 ℃, and gradually add dendritic polyol (CYD H2O) to the reaction flask in 3 portions. After reacting for 2 h, CYD H2O is completely dissolved.

[0028] C. Stir the mixture obtained in step B, M-8805, polyether 403, triethanolamine, HCFC-141b, methyl formate, TCEP, and PC-5 at a speed of 2000 rpm until they are evenly mixed to obtain component A; D. PM200 (component B) is quickly added to the polyol mixture and stirred at 25 °C to obtain PU slurry; E. The PU slurry is quickly injected into a preheated mold for foaming (the entire mold can be filled in one pour), and then the mold and slurry are treated at 60 °C and cooled to room temperature to obtain the rigid polyurethane foam.

[0029] The test shows that the viscosity of the polyol combination material is 1086 mPa·s, which can meet the process requirement of foaming; the milky white time is 45 seconds, and the non-stick time is 180 seconds. The density of the high-strength, high-toughness and impact-resistant rigid polyurethane foam plastic prepared is 74 kg / m 3 , the thermal conductivity is 0.026 W / (m·K), the compressive strength is 0.80 MPa, the size change rate is 0.23%, the cell is regular, uniform and dense. It shows that the high-strength, high-toughness and impact-resistant rigid polyurethane foam plastic prepared in this embodiment is light in weight, strong in bearing capacity, good in heat insulation performance and excellent in size stability. Specific implementation 2 The difference between this embodiment and embodiment 1 is only that the catalyst T-9 is replaced by catalyst T-12.

[0031] The test shows that the viscosity of the polyol combination material is 1090 mPa·s, which can meet the process requirement of foaming; the milky white time is 40 seconds, and the non-stick time is 165 seconds. The density of the high-strength, high-toughness and impact-resistant rigid polyurethane foam plastic prepared is 73 kg / m 3 , the thermal conductivity is 0.024 W / (m·K), the compressive strength is 0.81 MPa, the size change rate is 0.22%, the cell is regular, uniform and dense. It shows that the high-strength, high-toughness and impact-resistant rigid polyurethane foam plastic prepared in this embodiment is light in weight, strong in bearing capacity, good in heat insulation performance and excellent in size stability.

[0032] Comparative example 1 The difference between this embodiment and embodiment 1 is only that the catalyst T-9 is not added in step B, and the catalyst is added when preparing component A in step C.

[0033] The test shows that the viscosity of the polyol combination material is 1548 mPa·s, which does not meet the process requirement of foaming; the density of the rigid polyurethane foam plastic prepared is 75 kg / m3, the thermal conductivity is 0.035 W / (m·K), the compressive strength is 0.45 MPa, the size change rate is 0.29%, and the cell is irregular, non-uniform and non-dense. It shows that the rigid polyurethane foam prepared in this embodiment has lower strength compared with embodiment 1, and the reason is that CYD H20 in this embodiment cannot be dissolved in the commercial polyol, and exists in the form of powder, which leads to low crosslinking degree of the foam and unobvious strength improvement.

[0034] Comparative example 2 The difference between this embodiment and embodiment 1 is only that no dendritic polyester polyol (CYD H20) is added.

[0035] The test shows that the viscosity of the polyol combination material is 1200-1300 mPa·s, meeting the foaming process requirement; the density of the prepared rigid polyurethane foam is 74 kg / m 3 , the thermal conductivity is 0.033 W / (m·K), the compression strength is 0.38 MPa, the size change rate is 0.21%, the cells are regular, uniform and dense. It is shown that the strength of the rigid polyurethane foam prepared in the embodiment is lower than that of the embodiment 1, and the reason is that there is no high-functionality dendritic structure to improve the crosslinking density of the polyurethane foam in the embodiment, resulting in the decrease of the compression strength, and the increase of the brittleness and the decrease of the impact resistance.

[0036] Performance detection method The rigid polyurethane foam prepared in the application is tested by the following method: Apparent core density: the density of the foam is measured according to GB / T 6343-2009, the size specification is 100 mm×100 mm×50 mm, five samples are a group, and the data is averaged.

[0037] Compression performance test: the foam plastic is cut into a sample with a size of 100 mm×100 mm×50 mm, and the compression performance test is carried out on an electronic universal testing machine according to GB / T 8813-2008. The compression rate is 5 mm / min. Five samples are a group, and the data is averaged.

[0038] Dimensional stability test: the dimensional stability of the foam is tested according to GB / T 8811-2008, the size specification is 100 mm×100 mm×25 mm, three samples are a group, and the data is averaged.

[0039] Thermal conductivity test: the thermal conductivity of the foam is tested according to GB / T 3399-1982, the size specification is 40 mm×40 mm×5 mm, two samples are a group, and the data is averaged.

[0040] In summary, the preparation process of the high-strength, high-toughness and impact-resistant rigid polyurethane foam plastic provided by the application realizes the liquefaction of the powder dendritic polyol molecules by using a simple one-step ester exchange reaction, and the catalyst does not need to be removed after the reaction, saving the time of post-treatment and the reaction condition is simple. At the same time, the raw materials are commercialized, widely sourced and low-cost, having certain advantages in time and cost, and being easy to mass industrialized preparation.

[0041] The specific embodiments of the application are described above. It should be understood that the application is not limited to the above specific embodiments, and those skilled in the art can make various modifications or changes within the scope of the claims, which does not affect the essential content of the application.

Claims

1. A high-strength rigid polyurethane foam, characterized by, The high-strength, high-toughness, impact-resistant rigid polyurethane foam is prepared from the following raw materials by weight parts: Commercial polyester polyol 100 parts; Dendritic polyester polyol 10-40 parts; Late-stage catalyst 0.1-0.3 parts; Early-stage catalyst 0.1-0.3 parts; Foam stabilizer 1-3 parts; Crosslinking agent 5-15 parts; Foaming agent 0.5-20 parts; Flame retardant 5-15 parts; Polyisocyanate 100-150 parts.

2. The high-strength rigid polyurethane foam according to claim 1, characterized in that, The commercial polyester polyol includes one or more of 3152, 2452, 2412, 3302, etc. phthalic anhydride polyester polyol, with a hydroxyl value of 200-350 mgKOH / g and a viscosity of 1000 mpa·s to 8000 mpa·s.

3. The high-strength rigid polyurethane foam according to claim 1, wherein The dendritic polyester polyol includes one or more of CYD H10, CYD H20, CYD H30, CYD H40. The dendritic polyester polyol has 8-64 terminal hydroxyl groups, a molecular weight of 500-7300 g / mol, and a hydroxyl value of 670-530 mg KOH / g.

4. The high-strength rigid polyurethane foam according to claim 1, wherein The late-stage catalyst is one or both of T-9 (stannous octoate) and T-12 (dibutyltin dilaurate), and the early-stage catalyst is PC-5 (pentamethyldiethylene triamine).

5. The high-strength rigid polyurethane foam according to claim 1, wherein The foam stabilizer is one or more of M-8805, M-8808, M-8809, M-8815, M-8860, M-88308, M-88310, M-88108, M-88109, M-88716, M-88719.

6. The high-strength rigid polyurethane foam according to claim 1, wherein The crosslinking agent is one or more of glycerol, pentaerythritol, sorbitol, sucrose, and polyether 403.

7. The high-strength rigid polyurethane foam according to claim 1, wherein The foaming agent includes one or both of a physical foaming agent and a chemical foaming agent, wherein the physical foaming agent is one or more of HFC-245fa, HFC-134a, HFC-365mfc, HFC-227ea, HCFC-141b, methyl formate, cyclopentane, n-pentane, cycloisopentane, and 3,3-trifluoropropene; and the chemical foaming agent is water.

8. The high-strength, high-toughness, impact-resistant rigid polyurethane foam according to claim 1, wherein The flame retardant is one or more of TCPP, TCEP, and TEP.

9. The high-strength rigid polyurethane foam according to claim 1, wherein The -NCO content of the polyisocyanate is 30 to 35 %, the functionality is 2.5 to 2.9, the viscosity is 150 to 250 mPa-s, the density is 1.20 to 1.30 g-cm -3 .

10. A process for the production of high-strength rigid polyurethane foam as claimed in any one of claims 1 to 9, characterized in that, The method comprises the following steps: The raw materials of the high-strength, high-toughness, impact-resistant rigid polyurethane foam are weighed by weight parts respectively; The commercial polyester polyol is added to a reaction bottle, the late-stage catalyst is added, the temperature is raised to 190-220°C, the dendritic polyol is gradually added to the reaction bottle in 3-4 portions, and after 2-3 hours of reaction, the dendritic polyol is completely dissolved; The mixture obtained in step B, the foam stabilizer, the crosslinking agent, the foaming agent, the flame retardant, and the early-stage catalyst are stirred at a speed of 800-2000 rpm to obtain component A; The polyisocyanate (component B) is quickly added to the polyol mixture, and the PU slurry is obtained by stirring at 25-35°C; The PU slurry is quickly injected into a preheated mold (50 cm wide * 150 cm high * 2 cm) for foaming, and then the mold is treated at 60-120°C, and cooled to room temperature to obtain the rigid polyurethane foam.

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