Low-density, high-strength and high-damping rigid polyurethane foam as well as preparation method and application thereof

Abstract

The invention belongs to the field of synthesis and preparation of advanced materials, and particularly relates to low-density, high-strength and high-damping rigid polyurethane foam as well as a preparation method and application thereof. According to the invention, the specific molecular structure design of the rigid polyurethane foam is realized through the copolymerization reaction of polyether and polyester polyol with various special structures, and a series of rigid polyurethane foam materials with significantly improved damping performance are prepared. The rigid polyurethane foam not only has low density, high strength and modulus, but also has good damping buffer and impact resistance characteristics, extremely low water absorption rate and excellent stability, and has good application prospects in the fields of aerospace, ocean engineering, ship transportation, military equipment, automobile industry and the like.

Description

Technical Field

[0001] The invention belongs to the field of advanced material synthesis and preparation, and specifically relates to a low-density, high-strength, high-damping rigid polyurethane foam and a preparation method and application thereof. Background Art

[0002] Rigid polyurethane foam is a porous structure material generated by chemical reaction with polyol and isocyanate as the main reactants. The material has the characteristics of low density, high strength, excellent thermal insulation performance, good mechanical properties and compressive strength. Rigid polyurethane foam can be customized according to its density, hardness, structure and purpose, and is widely used in aerospace, ocean shipping, protective equipment, construction and automobile fields.

[0003] During the transportation of aerospace vehicles, important parts such as engines, wings, and bulkheads not only need to have load-bearing capacity, but also do not change shape when subjected to external forces and maintain sufficient stability. At the same time, it is necessary to effectively absorb various vibrations caused by the flight process to avoid short-term severe vibrations and persistent vibrations that damage internal precision instruments and aircraft structures, and improve the stability and life of the aircraft. For shipbuilding and offshore platform construction, it is necessary to resist the impact of external waves and the vibration of internal engines and motors running at high speeds. Such impacts and vibrations are often difficult to avoid, so they need to have high strength to resist external effects, and high damping performance is also required to meet their needs to reduce vibration and impact, convert them into heat energy, electrical energy, magnetic energy and other energies, and achieve the effect of vibration reduction. In the above-mentioned application fields, engines, high-speed flight of aircraft, internal combustion engines in the energy field, transformers, etc., under working conditions, the severe and high-frequency vibrations they bring, and the high temperature conditions caused by long-term operation all put forward higher requirements for the use of structural materials. In order to reduce the life loss of internal electronic components and the structural damage of the material itself, it is of great significance to improve the damping performance of rigid polyurethane foam.

[0004] While achieving high strength and high modulus, rigid polyurethane foams usually face the challenge of reduced damping performance. Based on the relationship between the molecular structure and mechanical properties of the material: the main chain structure of polyurethane mainly includes soft segment structure and hard segment structure. Generally, the soft segment structure mainly includes polyether / polyester polyols, and the hard segment structure mainly includes isocyanate, chain extender and foaming agent. The hard segment contains a large number of polar groups and a large number of hydrogen bonds, which can promote the aggregation of the hard segment and produce appropriate microphase separation, so that the polyurethane has a higher damping factor (tanδ). In rigid polyurethane foam, in order to meet high strength and high rigidity, it is usually necessary to increase the hard segment ratio, cross-linking degree and other methods to achieve it; on the contrary, the damping performance is mainly determined by the flexibility of the molecular chain and the microphase separation between the hard segment and the soft segment. Therefore, improving strength and rigidity often comes at the expense of the freedom, flexibility and energy absorption capacity of the molecular chain, resulting in reduced damping performance. It is very challenging to achieve a balance between strength, rigidity and damping performance.

[0005] Therefore, scholars and researchers at home and abroad have adopted a variety of approaches to improve the damping performance of rigid polyurethane foam. Commonly used methods include: by adding nanofillers such as graphene, increasing the energy loss during the movement of polyurethane chain segments and improving the damping performance, but there are problems such as complex processing technology, increased material density, and poor dispersibility; by constructing an interpenetrating polymer network structure (IPN), two or more types of polymers are cross-linked to form a three-dimensional network to achieve a complex multiphase system, thereby improving the viscoelasticity and damping performance of the material, but the formation of IPN involves a variety of polymers, and external conditions such as reaction raw materials and temperature need to be strictly controlled, the preparation is difficult, and the material itself is not conducive to recycling; magnetic fillers (such as ferrite powder, etc.) can also be added to introduce magnetic damping, and the energy conversion and dissipation capacity of the foam can be improved through the interaction between the magnetic field and vibration, but there are problems such as large addition amount, easy aggregation, and increased foam density; by preparing composite materials for modification, polyurethane foam is compounded with elastic materials such as rubber and silicone, which significantly improves the viscoelasticity and elasticity of the foam and can have a higher energy absorption capacity, but there are compatibility issues between the foam and rubber, and the improvement effect is small, which has a great limitation on its practical application.

[0006] Therefore, exploring a preparation process that is simple to operate and easy to use in large quantities to prepare rigid polyurethane foam with low density, high strength and high damping performance is a problem and challenge faced by this field. Summary of the invention

[0007] In view of the defects of the prior art, the present invention provides a low-density, high-strength, high-damping performance rigid polyurethane foam and a preparation method and use thereof.

[0008] The present invention provides a low-density, high-strength, high-damping rigid polyurethane foam, which is prepared by using raw materials including the following parts by weight:

[0009] Polyether / polyester polyol A 80-140 parts,

[0010] Polyether / polyester polyol B 3-25 parts,

[0011] Chain extender 5-30 parts,

[0012] 5 to 36 parts of crosslinking agent,

[0013] 0.5-4.0 parts of foaming agent,

[0014] 100-300 parts of isocyanate;

[0015] The polyether / polyester polyol B is phthalic anhydride polyester polyol.

[0016] Preferably, the isocyanate index R is 1 to 1.25.

[0017] Preferably, the polyether polyol A is selected from 4110 polyether polyol, 8345 polyether polyol, 2490 polyether polyol, the polyester polyol A is selected from polyethylene phthalate glycol ester diol, polyneopentyl phthalate glycol ester diol, PS-3512 phthalic anhydride polyester diol, the chain extender is selected from aliphatic diols: 1,2-propylene glycol, ethylene glycol, 1,2-pentanediol, 1,2-octanediol, diethylene glycol, aromatic diamines: 4,4-bis-sec-butylaminodiphenylmethane, toluenediamine; the cross-linking agent is selected from glycerol, trimethylolethane, diethanolamine, triethanolamine, diethylenetriamine; the foaming agent is water.

[0018] Preferably, the isocyanate is selected from polyphenyl polymethylene polyisocyanate and diphenylmethane diisocyanate.

[0019] The present invention provides a low-density, high-strength, high-damping rigid polyurethane foam as described in any one of the above, which is prepared by a method comprising the following steps:

[0020] Step 1, polyether / polyester polyol A is mixed with polyether / polyester polyol B, a chain extender, a crosslinking agent, and a foaming agent to prepare a polyol mixture;

[0021] Step 2, isocyanate reacts with the polyol mixture and ages to obtain a product.

[0022] Preferably, in step 1, the mixing is mixing polyether / polyester polyol A with polyether / polyester polyol B, a chain extender, a cross-linking agent, a foaming agent, a foam stabilizer, an amine catalyst and an antioxidant.

[0023] Preferably, the foam stabilizer is selected from S-6920 foam stabilizer and AK8805 surfactant; and / or the amine catalyst is 2040 catalyst; and / or the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0024] Preferably, the weight ratio of polyether / polyester polyol A to foam stabilizer, amine catalyst and antioxidant is 80-140:0.5-5:0.1-1:0.5-4.

[0025] Preferably, in step 1, the mixing is stirring at a speed of 2800 to 7000 r / min for 30 to 80 s;

[0026] And / or, in step 2, the reaction is that isocyanate is added to the polyol mixture, stirred at a speed of 2800 to 7000 r / min for 20 to 25 seconds, and the uniformly mixed material is poured into a mold and foamed for 180 to 400 seconds;

[0027] And / or, in step 2, the aging is curing at 20-25° C. for 20-26 hours.

[0028] Preferably, when the polyether / polyester polyol B is selected from 1,4-butanediol-adipate PBA-1000, tetrahydrofuran polyether PTMG850, tetrahydrofuran polyether PTMG1000, and tetrahydrofuran polyether PTMG-2000, before the mixing in step 1, the polyether / polyester polyol B is heated at 50° C. for 5 to 30 minutes.

[0029] The present invention also provides a method for preparing the rigid polyurethane foam with low density, high strength and high damping performance as described in any one of the above, which comprises the following steps:

[0030] Step 1, polyether / polyester polyol A is mixed with polyether / polyester polyol B, a chain extender, a crosslinking agent, and a foaming agent to prepare a polyol mixture;

[0031] Step 2, isocyanate reacts with the polyol mixture and ages to obtain a product.

[0032] The present invention also provides the use of the low-density rigid polyurethane foam with excellent damping performance as a material in aerospace vehicles, marine engineering, ship transportation, automobile industry, protective equipment, and military equipment.

[0033] The numbering of terms such as "A" and "B" only serves to distinguish different terms, does not indicate any priority or order, and does not limit the scope of the description of technical features.

[0034] The present invention provides a low-density, high-strength, high-damping rigid polyurethane foam. The specific molecular structure design of the rigid polyurethane foam is realized by copolymerization of polyether and polyester polyol of various special structures, and a series of rigid polyurethane foam materials with significantly improved damping performance are prepared. These materials have low density, high strength and high damping performance. In particular, when the introduced polyether (or polyester) polyol is phthalic anhydride polyester polyol PA, various properties are more excellent. The rigid polyurethane foam also has good toughness, deformation resistance, impact resistance, low water absorption and good stability, showing the development potential in the fields of aerospace, marine engineering, ship transportation, military equipment and automobile industry, and has good application prospects.

[0035] The present invention realizes the molecular structure design of the polyurethane soft segment by only adding polyether / polyester polyols with different structures and different molecular weights to the 4110 polyether for copolymerization reaction. Compared with other schemes, the production process of the present invention is obviously simple, and the raw materials are mixed after preheating part of the solid polyol, and the one-step molding technology has simple process, low cost and more industrial application potential.

[0036] Compared with adding nanocomposite fillers, the present invention does not need to use ultrasonic dispersion equipment to realize the processing and mixing of nanofillers, and there will be no agglomeration and precipitation of nanofillers during the mixing process, resulting in uneven material dispersion; while constructing an IPN structure involves a cross-linking reaction between multiple different types of polymers, which requires more control of the reaction raw materials and reaction conditions; from the perspective of introducing magnetic filler to enhance the magnetic damping of the material to increase energy dissipation, the magnetic material has aggregation and requires special dispersion technology. At the same time, after long-term use, the magnetic filler particles will fall off and decompose, the performance will decrease, and the recovery process will be more difficult, and the cost and technology of recycling will be greatly improved. By using a chain extender with different lengths of hanging chains, the hanging chains are introduced into the polyurethane hard segment structure to improve the damping performance of the polyurethane. The material form of the chain extender is mostly solid, and in order to ensure that the reaction is complete, it needs to be preheated in advance and foamed using a semi-prepolymer method, which is difficult to process and increases the cost. If a one-step molding preparation method is used, there will be a problem of uneven dispersion, which affects the uniformity of the foam.

[0037] Obviously, according to the above contents of the present invention, in accordance with common technical knowledge and customary means in the art, without departing from the above basic technical ideas of the present invention, other various forms of modification, replacement or change may be made.

[0038] The above contents of the present invention are further described in detail below through specific implementation methods in the form of embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples. All technologies realized based on the above contents of the present invention belong to the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION

[0039] In the following examples and experimental examples, reagents and materials not particularly described are all commercially available.

[0040] In the following examples, different chain extenders were selected, and the amount of the chain extender was converted according to the hydroxyl value parameter.

[0041] Example 1 A modified rigid polyurethane foam material and a preparation method thereof

[0042] The modified polyurethane material of this embodiment is prepared by the following method:

[0043] First, place 4110 polyether polyol in a refrigerator at 5°C for 24h. Then, add 90.05g 4110 polyether polyol, 10.01g phthalic anhydride polyester polyol PA (CAS No.: 32472-85-8), 7.36g 1,2-propylene glycol, 9.01g propylene glycol, 1.31g water, 2.10g S-6920 foam stabilizer, 0.405g 2040 catalyst and 1.84g tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester to the container. Stir the agitator at 3000r / min for 75s to allow the polyether polyol mixture to be fully mixed. Weigh 192.47g polyphenyl polymethylene polyisocyanate, the isocyanate index R is 1.05. After the stirring is completed, the isocyanate is quickly added to the polyol mixture and stirred at a speed of 3000r / min for 20-25s. Finally, the stirred combination is poured into the mold for foaming for 232s. After the foaming process is completed, it is aged at room temperature for 24h and then taken out for use.

[0044] Example 2 A modified rigid polyurethane foam material and a preparation method thereof

[0045] The method of Example 1 is followed, except that 10.01 g of phthalic anhydride polyester polyol PA is replaced by 10.00 g of polypropylene glycol PPG-200, the amount of 4110 polyether polyol is 90.04 g, the amount of 1,2-propylene glycol is 7.34 g, the amount of water is 1.30 g, the amount of 2040 catalyst is 0.40 g, and the amount of polyphenyl polymethylene polyisocyanate is 197.51 g.

[0046] Example 3 A modified rigid polyurethane foam material and its preparation method

[0047] The method of Example 1 is followed, except that phthalic anhydride polyester polyol PA is replaced by polypropylene glycol PPG-400, the amount of 4110 polyether polyol is 90.01 g, the amount of 1,2-propylene glycol is 7.35 g, the amount of water is 1.305 g, the amount of S-6920 foam stabilizer is 2.11 g, the amount of 2040 catalyst is 0.40 g, the amount of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is 1.85 g, and the amount of polyphenyl polymethylene polyisocyanate is 196.45 g.

[0048] Example 4 A modified rigid polyurethane foam material and its preparation method

[0049] The method of Example 1 is followed, except that phthalic anhydride polyester polyol PA is replaced by polypropylene glycol PPG-600, the amount of 4110 polyether polyol is 90.04 g, the amount of 1,2-propylene glycol is 7.35 g, the amount of 2040 catalyst is 0.41 g, the amount of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is 1.85 g, and the amount of polyphenyl polymethylene polyisocyanate is 189.41 g.

[0050] Example 5 A modified rigid polyurethane foam material and its preparation method

[0051] The method of Example 1 is followed, except that phthalic anhydride polyester polyol PA is replaced by polypropylene glycol PPG-1000, the amount of 4110 polyether polyol is 90.04 g, the amount of propylene glycol is 9.00 g, the amount of water is 1.30 g, the amount of S-6920 foam stabilizer is 2.105 g, the amount of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is 1.85 g, and the amount of polyphenyl polymethylene polyisocyanate is 188.07 g.

[0052] Example 6 A modified rigid polyurethane foam material and its preparation method

[0053] The method of Example 1 is followed, except that phthalic anhydride polyester polyol PA is replaced by polypropylene glycol PPG-1500, the amount of 4110 polyether polyol is 90.13 g, the amount of 1,2-propylene glycol is 7.35 g, the amount of glycerol is 9.00 g, the amount of water is 1.305 g, the amount of S-6920 foam stabilizer is 2.10 g, the amount of 2040 catalyst is 0.41 g, and the amount of polyphenyl polymethylene polyisocyanate is 188.24 g.

[0054] Example 7 A modified rigid polyurethane foam material and its preparation method

[0055] The method of Example 1 is followed, except that 10.01 g of phthalic anhydride polyester polyol PA is replaced by 10.02 g of tetrahydrofuran polyether PTMG-650, the amount of 4110 polyether polyol is 90.06 g, the amount of 1,2-propylene glycol is 7.34 g, the amount of water is 1.30 g, the amount of S-6920 foam stabilizer is 2.105 g, the amount of 2040 catalyst is 0.40 g, the amount of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is 1.85 g, and the amount of polyphenyl polymethylene polyisocyanate is 186.84 g.

[0056] Example 8 A modified rigid polyurethane foam material and its preparation method

[0057] According to the method of Example 1, the difference is that 10.01g of phthalic anhydride polyester polyol PA is replaced by 10.00g of tetrahydrofuran polyether PTMG-850, the amount of 4110 polyether polyol is 90.06g, the amount of 1,2-propylene glycol is 7.34g, the amount of water is 1.305g, the amount of S-6920 foam stabilizer is 2.105g, the amount of 2040 catalyst is 0.41g, and the amount of polyphenyl polymethylene polyisocyanate is 185.82g. PTMG-850 is a waxy solid or a colorless transparent liquid (depending on the ambient temperature). In order to ensure uniform mixing of the materials, the tetrahydrofuran polyether PTMG-850 needs to be preheated in advance, heated in a 50°C oven for 30min, and then mixed with other materials.

[0058] Example 9 A modified rigid polyurethane foam material and its preparation method

[0059] The method of Example 1 is followed, except that phthalic anhydride polyester polyol PA is replaced by tetramethylene ether PTMG-1000, the amount of 4110 polyether polyol is 90.01 g, the amount of 1,2-propylene glycol is 7.35 g, the amount of water is 1.30 g, and the amount of polyphenyl polymethylene polyisocyanate is 187.31 g. The treatment method of tetramethylene ether PTMG-1000 is the same as that of Example 8.

[0060] Example 10 A modified rigid polyurethane foam material and a preparation method thereof

[0061] The method of Example 1 is followed, except that phthalic anhydride polyester polyol PA is replaced by tetrahydrofuran polyether PTMG-2000, the amount of 4110 polyether polyol is 90.04 g, the amount of 1,2-propylene glycol is 7.35 g, the amount of water is 1.30 g, the amount of S-6920 foam stabilizer is 2.105 g, and the amount of polyphenyl polymethylene polyisocyanate is 187.67 g. The treatment method of tetrahydrofuran polyether PTMG-1000 is the same as that of Example 8.

[0062] Example 11 A modified rigid polyurethane foam material and a preparation method thereof

[0063] The method of Example 1 is followed, except that phthalic anhydride polyester polyol PA is replaced by tetrahydrofuran polyether PTMG-2000, the amount of 4110 polyether polyol is 90.04 g, the amount of 1,2-propylene glycol is 7.34 g, the amount of glycerol is 9.04 g, the amount of S-6920 foam stabilizer is 2.11 g, the amount of 2040 catalyst is 0.395 g, and the amount of polyphenyl polymethylene polyisocyanate is 188.40 g. The treatment method of tetrahydrofuran polyether PTMG-1000 is the same as that of Example 8.

[0064] Comparative Example 1

[0065] The preparation method of Example 1 is followed, except that phthalic anhydride polyester polyol PA is not used, the amount of 4110 polyether polyol is 100.01 g, the amount of 1,2-propylene glycol is 7.35 g, the amount of glycerol is 9.00 g, the amount of water is 1.15 g, the amount of S-6920 foam stabilizer is 2.11 g, the amount of 2040 catalyst is 0.40 g, and the amount of polyphenyl polymethylene polyisocyanate is 173.73 g.

[0066] Comparative Example 2

[0067] The preparation method of Example 1 is followed, except that phthalic anhydride polyester polyol PA is not used, the amount of 4110 polyether polyol is 100.04 g, the amount of 1,2-propylene glycol is 7.345 g, the amount of water is 1.11 g, the amount of S-6920 foam stabilizer is 2.12 g, the amount of 2040 catalyst is 0.41 g, the amount of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is 1.85 g, and the amount of polyphenyl polymethylene polyisocyanate is 173.73 g.

[0068] Comparative Example 3

[0069] The preparation method of Example 1 is followed, except that phthalic anhydride polyester polyol PA is not used, the amount of 4110 polyether polyol is 100.02 g, the amount of 1,2-propylene glycol is 7.34 g, the amount of water is 1.09 g, the amount of S-6920 foam stabilizer is 2.105 g, and the amount of polyphenyl polymethylene polyisocyanate is 189.39 g.

[0070] The technical solution of the present invention is further illustrated by experiments below.

[0071] In the following experimental examples, the tested materials are rigid polyurethane foam materials prepared according to the methods described in Examples 1-11 and Comparative Examples 1-3, respectively.

[0072] Experimental Example 1 Characterization of Density and Damping Performance of Polyurethane Materials

[0073] Rigid polyurethane foam (RPUF) is prepared by reacting polyether (or polyester) polyol and polyisocyanate in the presence of auxiliary agents such as blowing agent, catalyst, foam stabilizer, etc.

[0074] In the comparative example, 4110 polyether single component was used as polyether polyol to successfully prepare a rigid polyurethane foam material; in the example, 4110 polyether was compounded with other different types of polyether (or polyester) polyols at a weight ratio of 1:9 to prepare a modified rigid polyurethane foam material. This experimental example screened out a low-density rigid polyurethane foam material with excellent damping performance by comparing the density, the maximum value of the loss factor (Tanδ) and the glass transition temperature.

[0075] 1. Experimental Methods

[0076] 1. Determination of density

[0077] According to GB / T 6343-2009, after removing the surface skin, the foam is cut into standard cubic samples with a size of 30mm×30mm×30mm. Take 8 samples at random, measure the length, width and height of the samples with a vernier caliper to an accuracy of 0.02mm, and then weigh the mass of the foam samples with an analytical balance. The ratio of the sample mass to the sample volume is the apparent core density of the polyurethane foam.

[0078] 2. Determination of 25℃ loss factor Tanδ, maximum loss factor (Tanδmax) and glass transition temperature (Tg)

[0079] (1) The dimensions of the sample were measured using a vernier caliper, and the average value of the measurements at multiple locations was recorded on a dynamic mechanical analyzer (DMA).

[0080] (2) Mode selection on the dynamic thermomechanical analyzer: Static load control is controlled by the size of the contact force, the contact force is 0.1N, the proportional factor is 1.3, and the static strain limit is 1%. Dynamic load control is deformation control, the dynamic deformation is 0.03mm, the dynamic force limit is 20N, the alternating load is none, and the load frequency is 1Hz. Liquid nitrogen refrigeration is selected for atmospheric conditions, and the purge gas is turned on. Maintain a heating rate of 5K / min, increase the temperature from 0℃ to 230℃, and keep warm for 300s. The equipment will record the data of its tanδ changing with temperature in real time. Save the parameters, name the file, and run the program. After completing the experiment, export the data and find the tanδ value at 25℃.

[0081] The peak value corresponding to the loss peak is obtained by peak marking with data processing software as Tanδmax, the temperature corresponding to the peak value of the loss peak is the glass transition temperature Tg, and the average value of multiple samples is taken.

[0082] 2. Experimental Results

[0083] The results are shown in Table 1: According to the method of the embodiment of the present invention, the modified polyurethane material prepared by compounding other polyether (or polyester) polyols with 4110 polyether has a density equivalent to that of the comparative example, or a small change. This shows that the method of the present invention ensures that the polyurethane material has a lower density.

[0084] Compared with the comparative example, when other polyether (or polyester) polyols are introduced and compounded with 4110 polyether, the Tg of the polyurethane material is significantly reduced and the Tanδmax is significantly improved. In particular, when the compounded polyether (or polyester) polyol is phthalic anhydride polyester polyol PA, the Tanδmax of the polyurethane material is most significantly improved and the Tg is reduced the most.

[0085] The above results show that when other polyether (or polyester) polyols are introduced and compounded with 4110 polyether, the density of the polyurethane material does not change significantly, but Tg is significantly reduced and Tanδmax is significantly improved, proving that the damping properties of the material have been significantly improved. In particular, when the other polyether (or polyester) polyol is phthalic anhydride polyester polyol PA, the improvement in damping properties is most obvious.

[0086] Table 1 Determination results of density, Tanδmax, Tg and Tanδ

[0087]

[0088]

[0089] Experimental Example 2 Characterization of other properties of polyurethane materials

[0090] 1. Experimental Methods

[0091] 1. Determination of compressive strength and modulus

[0092] Test compressive strength and compressive modulus: refer to GB 8813-2020 "Determination of compression properties of rigid foam plastics", the sample size is 30mm×30mm×30mm, and the compression rate is 3mm / min. The yield strength is selected as the compressive strength, and according to the derived displacement-force curve, the tangent at the maximum slope of the curve is selected, and its corresponding value is the compression modulus.

[0093] 2. Determination of flexural strength and flexural modulus

[0094] Bending strength, refer to GB8812.1-2007 "Determination of flexural properties of rigid foam plastics Part 1: Basic bending test" for sample preparation, sample size 120mm×25mm×20mm, span 100mm, test speed 10mm / min. Record its load-strain curve, when the sample is less than 5% strain, record the breaking load. Calculation of bending strength and bending modulus refers to GBT8812.2-2007 "Determination of bending strength and apparent bending elastic modulus".

[0095] 3. Determination of impact strength

[0096] According to GB / T 1043.1-2008 "Determination of impact properties of plastic simply supported beams", the unnotched simply supported beam impact test was carried out, the sample size was 120mm×15mm×10mm, the test span was 70mm, the test pendulum was 2J, and the speed was 2.9mm / s. The fracture strength was selected as the impact strength.

[0097] 4. Determination of non-stick time S

[0098] Test non-stick time: According to the definition of various foaming reaction characteristic parameters, test conditions and test methods in HG / T 4574-2014 "Determination method of foaming reaction characteristics of polyurethane raw materials", non-stick time and other parameters are measured. That is, the time from the beginning of material mixing to the time when the gloved finger or glass rod touches the foam surface without sticking.

[0099] 5. Determination of water absorption

[0100] Select a sample of 150mm×150mm×30mm, and obtain the dry weight m1 and foam volume v by measurement. Immerse the sample in water, and remove bubbles on the surface of the sample with a soft brush or by stirring. Weigh again after 24 hours to obtain the wet weight m2. Water absorption rate = (m2-m1) / v.

[0101] 2. Experimental Results

[0102] The results of other properties are shown in Table 2: The introduction of other polyether polyols and polyester polyols in the preparation method of the present invention does not significantly reduce the compressive strength, bending performance, impact strength, non-stick time and water absorption of the rigid polyurethane foam. Among them, when the other polyether (or polyester) polyol introduced is phthalic anhydride polyester polyol PA, the various properties are relatively excellent.

[0103] Table 2 Determination results of other properties

[0104]

[0105]

[0106] The results show that when other polyether (or polyester) polyols are introduced into the preparation method of the present invention, the load-bearing capacity, rigidity, bending performance and water absorption rate of the rigid polyurethane foam will not be significantly reduced. In particular, when the other polyether (or polyester) polyol introduced is phthalic anhydride polyester polyol PA, various properties are relatively excellent and it has the potential for application in the fields of aerospace, marine engineering, ship transportation, military equipment, and automobile industry.

[0107] Through the above-mentioned embodiment and experimental example, it can be seen that the present invention provides a kind of low-density, high-strength, high-damping rigid polyurethane foam.The specific molecular structure design of rigid polyurethane foam is realized by copolymerization of polyether and polyester polyol of multiple special structures, and a series of rigid polyurethane foam materials with significantly improved damping performance are obtained.These materials have low-density, high-strength, high-damping performance.When the polyether (or polyester) polyol introduced is phthalic anhydride polyester polyol PA in particular, various performances are more excellent.This polyurethane material also has good toughness, impact resistance, low water absorption, good bending resistance and good stability, and shows the development potential in the fields of aerospace, marine engineering, ship transportation, military equipment, automobile industry, etc., and has good application prospects.

Claims

1. A low-density, high-strength, high-damping rigid polyurethane foam, characterized in that: The invention is prepared by using the following raw materials in parts by weight: Polyether / polyester polyol A 80-140 parts, Polyether / polyester polyol B 3-25 parts, Chain extender 5-30 parts, 5 to 36 parts of crosslinking agent, 0.5-4.0 parts of foaming agent, 100-300 parts of isocyanate; The polyether / polyester polyol B is phthalic anhydride polyester polyol.

2. The low-density, high-strength, high-damping rigid polyurethane foam according to claim 1, characterized in that: The isocyanate index R is 1 to 1.

25.

3. The low-density, high-strength, high-damping rigid polyurethane foam according to claim 1, characterized in that: The polyether polyol A is selected from 4110 polyether polyol, 8345 polyether polyol, and 2490 polyether polyol; the polyester polyol A is selected from polyethylene phthalate glycol ester diol, polyneopentyl phthalate glycol ester diol, and PS-3512 phthalic anhydride polyester diol; the chain extender is selected from aliphatic diols: 1,2-propylene glycol, ethylene glycol, 1,2-pentanediol, 1,2-octanediol, diethylene glycol, and aromatic diamines: 4,4-bis-sec-butylaminodiphenylmethane and toluenediamine; the cross-linking agent is selected from glycerol, trimethylolethane, diethanolamine, triethanolamine, and diethylenetriamine; and the foaming agent is water.

4. The low-density, high-strength, high-damping rigid polyurethane foam according to claim 1, characterized in that: The isocyanate is selected from polyphenyl polymethylene polyisocyanate and diphenylmethane diisocyanate.

5. The low-density, high-strength, high-damping rigid polyurethane foam according to any one of claims 1 to 4, characterized in that: It is prepared by a method comprising the following steps: Step 1, polyether / polyester polyol A is mixed with polyether / polyester polyol B, a chain extender, a crosslinking agent, and a foaming agent to prepare a polyol mixture; Step 2, isocyanate reacts with the polyol mixture and ages to obtain a product.

6. The low-density, high-strength, high-damping rigid polyurethane foam according to claim 5, characterized in that: In step 1, the mixing is mixing polyether / polyester polyol A with polyether / polyester polyol B, a chain extender, a cross-linking agent, a foaming agent, a foam stabilizer, an amine catalyst and an antioxidant.

7. The low-density, high-strength, high-damping rigid polyurethane foam according to claim 5, characterized in that: The foam stabilizer is selected from S-6920 foam stabilizer and AK8805 surfactant; and / or the amine catalyst is 2040 catalyst; and / or the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

8. The low-density, high-strength, high-damping rigid polyurethane foam according to claim 6, characterized in that: The weight ratio of polyether / polyester polyol A to foam stabilizer, amine catalyst and antioxidant is 80-140:0.5-5:0.1-1:0.5-4.

9. The method for preparing a low-density, high-strength, high-damping rigid polyurethane foam according to any one of claims 1 to 8, characterized in that: The steps include: Step 1, polyether / polyester polyol A is mixed with polyether / polyester polyol B, a chain extender, a crosslinking agent, and a foaming agent to prepare a polyol mixture; Step 2, isocyanate reacts with the polyol mixture and ages to obtain a product.

10. Use of the low-density rigid polyurethane foam with excellent damping performance as claimed in any one of claims 1 to 8 as a material in aerospace vehicles, marine engineering, ship transportation, automobile industry, protective equipment, and military equipment.

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