Monosaccharide modified polyurethane rigid foam as well as preparation method and application thereof

Abstract

The invention relates to the technical field of polyurethane foam, in particular to monosaccharide modified polyurethane rigid foam as well as a preparation method and application thereof. The monosaccharide modified polyurethane rigid foam is prepared from the following components: polyethylene glycol-400 partially substituted by monosaccharide or a monosaccharide liquefied product, polymethylene polyphenyl polyisocyanate, triethylamine, dibutyltin dilaurate, dimethyl silicone oil, n-pentane and water. The preparation method of the monosaccharide modified polyurethane foam comprises the following steps: preparing a monosaccharide partially substituted polyethylene glycol-400 mixed suspension or a monosaccharide liquefied product, and preparing the monosaccharide modified polyurethane rigid foam. According to the preparation method, the polyurethane foam is prepared by taking the green and renewable monosaccharide as a raw material instead of polyhydric alcohols, the preparation method is simple, the prepared monosaccharide modified polyurethane rigid foam is high in compression strength and good in thermal insulation performance, the performance index of the monosaccharide modified polyurethane rigid foam is far higher than the requirement of national III-class building thermal insulation rigid polyurethane foam, and the monosaccharide modified polyurethane rigid foam has wide market application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethane foam, and particularly relates to a monosaccharide-modified rigid polyurethane foam and its preparation method and application. Background Art

[0002] Polyurethane (PU), also known as polycarbamate, is an artificially synthesized polymer material, generally obtained by the interaction of binary or polyvalent organic isocyanates and polyols. Due to the differences in the structures of the prepared polyurethanes, their properties will also change. By using the different structures of polyurethanes, polyurethane polymers can be made into plastics, rubbers, fibers, coatings, adhesives, foams, etc. respectively. In recent years, the application of polyurethane in the preparation of polyurethane foams has become increasingly widespread. Polyurethane foam (PUF), as one of the main varieties of polyurethane synthetic materials, has attracted people's attention due to its unique physical properties (high porosity, low relative density, good mechanical properties, etc.) and good biocompatibility, making it widely used in fields such as construction, transportation, furniture, textiles, experimental research, etc.

[0003] Polyurethane foams are divided into soft polyurethane foams, semi-rigid polyurethane foams and rigid polyurethane foams. Among them, rigid polyurethane foam is a high-density closed-cell material, and due to its advantages of strong corrosion resistance, good sound insulation effect and excellent heat insulation performance, it has been widely used in refrigeration, construction projects, transportation and aviation fields. Polyols, as the main raw materials for the preparation of polyurethane foams, are mainly divided into polyether polyols and polyester polyols. Currently, polyester polyols are commonly used, which are generally synthesized from petroleum-based compounds. Considering the renewable nature and sustainable development of raw materials as well as environmental pollution, in recent years, scientific researchers have been working hard to find suitable substitutes for petroleum-based polyols.

[0004] In the prior art, the Chinese patent application for invention "A Preparation Method of a Bio-based Polyurethane Material" with the publication number CN113929858A discloses a bio-based rigid polyurethane foam material prepared by a full-water foaming method using starch-based polyether polyol and polymethylene polyphenyl polyisocyanate as the main raw materials. Its optimized formula is as follows: adding 1.0 - 2.0% of a surfactant, 2.0 - 3.0% of a foaming agent, 0.2 - 0.3% of a catalyst and 110 - 150% of isocyanate based on the mass of the polyol. Under the above optimized formula, the compression strength of the prepared bio-based polyurethane foam material is 238.5 - 374.7 KPa, and the apparent density is 48.1 - 58.3 kg / m 3, with a thermal conductivity of 0.016 - 0.024 W / (m·K) and a dimensional change rate of 1.5 - 2.9%, fully meeting the index requirements of the polyurethane insulation material SY / T 0415 - 96 standard. On the one hand, it provides degradability for the product, and on the other hand, it significantly reduces the preparation cost of polyurethane foam. However, the following problems still exist in this polyurethane foam: (1) The mixed polyol used in the raw materials for preparing polyurethane foam is prepared from bio - based polyol and petroleum - based polyol, and among them, the preparation method of bio - based polyol is relatively complex; (2) The mechanical strength of the prepared polyurethane foam is low and the heat - preservation performance is poor.

[0005] Based on the above problems, the present invention uses monosaccharide to replace part of polyethylene glycol - 400 as raw material to prepare monosaccharide - modified rigid polyurethane foam, aiming to provide a rigid polyurethane foam for building thermal insulation boards with low production cost, simple preparation method, high mechanical strength and good heat - preservation performance, and to realize the high - value utilization of biomass resources and reduce the dependence on fossil resources. Summary of the Invention

[0006] The purpose of the present invention is to provide a monosaccharide - modified rigid polyurethane foam.

[0007] Another purpose of the present invention is to provide a preparation method of the above - mentioned monosaccharide - modified rigid polyurethane foam.

[0008] A further purpose of the present invention is to provide the application of the above - mentioned monosaccharide - modified rigid polyurethane foam in the preparation of thermal insulation boards for building thermal insulation.

[0009] To achieve the above purposes, the technical solutions adopted by the present invention are as follows:

[0010] The monosaccharide - modified rigid polyurethane foam described in the present invention comprises the following components in parts by mass: 100 parts of monosaccharide - partially - replaced polyethylene glycol - 400 or monosaccharide liquefaction product, 98.5 parts of polymethylene polyphenyl polyisocyanate, 0.04 - 0.08 parts of triethylamine, 0.04 - 0.08 parts of dibutyltin dilaurate, 0.8 - 1.2 parts of dimethyl silicone oil, 3.0 - 4.0 parts of n - pentane, 0.12 - 0.24 parts of water;

[0011] The monosaccharide is one or two of xylose and glucose;

[0012] In the monosaccharide - partially - replaced polyethylene glycol - 400, the substitution rate of monosaccharide for polyethylene glycol - 400 is 10 - 20 wt%;

[0013] The monosaccharide liquefaction product is prepared by adding monosaccharide and polyethylene glycol - 400 into a two - necked flask with a stirring and reflux system, carrying out liquefaction, and then cooling to room temperature.

[0014] Preferably, the monosaccharide in the present invention is xylose.

[0015] Preferably, in the monosaccharide partially substituted polyethylene glycol-400 of the present invention, the substitution rate of the monosaccharide for polyethylene glycol-400 is 15-20 wt%.

[0016] More preferably, in the monosaccharide partially substituted polyethylene glycol-400 of the present invention, the substitution rate of the monosaccharide for polyethylene glycol-400 is 15 wt%.

[0017] Preferably, the monosaccharide liquefaction product of the present invention is prepared by adding monosaccharide and polyethylene glycol-400 with a mass ratio of 15:85 into a two-necked flask with a stirring and reflux system for liquefaction, setting the temperature at 120 °C, the time at 45 min, and the stirring speed at 500 r / min; immediately after the reaction, the flask is immersed in cold water and cooled to room temperature.

[0018] Preferably, in the formulation composition of the monosaccharide-modified polyurethane rigid foam of the present invention, the triethylamine is 0.06 parts by mass; the dibutyltin dilaurate is 0.06 parts by mass; the mass ratio of the triethylamine to the dibutyltin dilaurate is 1:1; the dimethyl silicone oil is 1 part by mass; the n-pentane is 3.5 parts by mass; the water is 0.18 parts by mass.

[0019] The preparation method of the monosaccharide-modified polyurethane rigid foam of the present invention includes the following steps:

[0020] S1 Prepare a monosaccharide partially substituted polyethylene glycol-400 mixed suspension or a monosaccharide liquefaction product; wherein, the preparation method of the monosaccharide partially substituted polyethylene glycol-400 mixed suspension is: adding monosaccharide into polyethylene glycol-400 and stirring at room temperature to obtain it;

[0021] S2 Prepare the monosaccharide-modified polyurethane rigid foam: sequentially add triethylamine, dibutyltin dilaurate, dimethyl silicone oil, n-pentane, and water into the monosaccharide partially substituted polyethylene glycol-400 mixed suspension or the monosaccharide liquefaction product prepared in step S1, stir for 5 min to obtain a mixed solution; then add polymethylene polyphenyl polyisocyanate into the mixed solution and continue to stir until the system turns white; pour the mixture into a mold and freely foam at room temperature; after the foam is cooled to room temperature, put it into an electric heating blast drying oven for curing, and take it out and cool to obtain the product.

[0022] Preferably, in the preparation method of the monosaccharide-modified polyurethane rigid foam of the present invention, the stirring speed of the stirring at room temperature in step S1 is 1000 r / min, and the stirring time is 1 h.

[0023] Preferably, in the preparation method of the monosaccharide-modified polyurethane rigid foam of the present invention, the curing temperature in step S2 is 80 °C, and the curing time is 1 h.

[0024] Application of the monosaccharide-modified polyurethane rigid foam in preparing a heat-insulating board for building thermal insulation.

[0025] Advantages of the present invention:

[0026] 1. The present invention uses green and renewable monosaccharides to partially replace polyethylene glycol-400 as raw materials to prepare polyurethane rigid foam. The process flow is simple and the production cost is low. It not only provides a new way for the high-value utilization of biomass resources, but also reduces the dependence on fossil resources in the production of polyurethane foam, and has broad market application prospects.

[0027] 2. The inventors compared and investigated the types of monosaccharides and substitution rates for partially replacing polyethylene glycol-400. The results showed that when xylose was used to partially replace polyethylene glycol-400 as the raw material and the xylose substitution rate was 15 wt%, the prepared monosaccharide-modified polyurethane rigid foam had high mechanical strength and the best heat insulation performance. Its density was 80.63 kg / m 3 , the compressive strength was 0.31472 MPa, and the thermal conductivity was 0.0074 W / (m·K). The above performance indicators are far higher than the requirements for rigid polyurethane foam for thermal insulation of Class III buildings in China. Description of the drawings

[0028] Figure 1 It is the morphology diagram of PU in Example 1;

[0029] Figure 2 It is the morphology diagram of PU in Comparative Example 3;

[0030] Figure 3 It is the morphology diagram of PU in Comparative Example 4;

[0031] Figure 4 It is the morphology diagram of PU in Comparative Example 5;

[0032] Figure 5 It is the morphology diagram of PU in Comparative Example 6;

[0033] Figure 6 It is the morphology diagram of PU in Comparative Example 7. Detailed implementation manners

[0034] The technical solutions of the present invention will be described in detail below in conjunction with specific embodiments. The following embodiments are only for explanation and illustration, and do not constitute a limitation to the technical solutions of the present invention.

[0035] Example 1

[0036] Xylose-modified polyurethane rigid foam formula:

[0037] 15 g of xylose, 85 g of polyethylene glycol - 400, 0.06 g of triethylamine, 0.06 g of dibutyltin dilaurate, 1.0 g of dimethyl silicone oil, 3.5 g of n - pentane, 0.18 g of water, 98.5 g of polymethylene polyphenyl polyisocyanate.

[0038] Preparation method of xylose - modified polyurethane rigid foam:

[0039] S1: Prepare a mixed suspension with xylose partially replacing polyethylene glycol - 400:

[0040] Take xylose and add it to polyethylene glycol - 400. Stir with an electric stirrer at a speed of 1000 r / min for 1 h at room temperature to make the above compounds evenly mixed, thus obtaining it.

[0041] S2: Prepare xylose - modified polyurethane rigid foam:

[0042] Add triethylamine, dibutyltin dilaurate, dimethyl silicone oil, n - pentane and water to the mixed suspension prepared in step S1 in sequence, stir for 5 min to obtain a mixed solution; then add polymethylene polyphenyl polyisocyanate to the mixed solution and continue stirring until the system turns white; pour the mixture into a mold and let it freely foam at room temperature; after the foam cools to room temperature, put it into an electro - thermal blast drying oven at 80 °C for curing for 1 d, and take it out and cool to obtain xylose - modified polyurethane rigid foam.

[0043] Example 2

[0044] Formulation of glucose - modified polyurethane rigid foam:

[0045] 15 g of glucose, 85 g of polyethylene glycol - 400, 0.06 g of triethylamine, 0.06 g of dibutyltin dilaurate, 1.0 g of dimethyl silicone oil, 3.5 g of n - pentane, 0.18 g of water, 98.5 g of polymethylene polyphenyl polyisocyanate.

[0046] Preparation method of glucose - modified polyurethane rigid foam:

[0047] S1: Prepare a mixed suspension with glucose partially replacing polyethylene glycol - 400:

[0048] Take glucose and add it to polyethylene glycol - 400. Stir with an electric stirrer at a speed of 1000 r / min for 1 h at room temperature to make the above compounds evenly mixed, thus obtaining it.

[0049] S2: Prepare glucose - modified polyurethane rigid foam:

[0050] Triethylamine, dibutyltin dilaurate, dimethyl silicone oil, n-pentane and water were successively added to the mixed suspension prepared in step S1, and stirred for 5 min to obtain a mixed solution; then polymethylene polyphenyl polyisocyanate was added to the mixed solution, and stirring was continued until the system turned white; the mixture was poured into a mold and freely foamed at room temperature; after the foam was cooled to room temperature, it was placed in an electric blast drying oven at 80 °C for curing for 1 day, and after taking out and cooling, glucose-modified polyurethane rigid foam was obtained.

[0051] Example 3

[0052] Formulation of mixed monosaccharide-modified polyurethane rigid foam:

[0053] Xylose 7.5 g, glucose 7.5 g, polyethylene glycol-400 85 g, triethylamine 0.06 g, dibutyltin dilaurate 0.06 g, dimethyl silicone oil 1.0 g, n-pentane 3.5 g, water 0.18 g, polymethylene polyphenyl polyisocyanate 98.5 g.

[0054] Preparation method of mixed monosaccharide-modified polyurethane rigid foam:

[0055] S1 Preparation of a mixed suspension with mixed monosaccharides partially replacing polyethylene glycol-400:

[0056] Xylose and glucose were taken and added to polyethylene glycol-400, and stirred with an electric stirrer at a rotation speed of 1000 r / min for 1 h at room temperature to make the above compounds evenly mixed, thus obtaining.

[0057] S2 Preparation of mixed monosaccharide-modified polyurethane rigid foam:

[0058] Triethylamine, dibutyltin dilaurate, dimethyl silicone oil, n-pentane and water were successively added to the mixed suspension prepared in step S1, and stirred for 5 min to obtain a mixed solution; then polymethylene polyphenyl polyisocyanate was added to the mixed solution, and stirring was continued until the system turned white; the mixture was poured into a mold and freely foamed at room temperature; after the foam was cooled to room temperature, it was placed in an electric blast drying oven at 80 °C for curing for 1 day, and after taking out and cooling, mixed monosaccharide-modified polyurethane rigid foam was obtained.

[0059] Example 4

[0060] Formulation of xylose-modified polyurethane rigid foam:

[0061] Xylose 15 g, polyethylene glycol-400 85 g, triethylamine 0.06 g, dibutyltin dilaurate 0.06 g, dimethyl silicone oil 1.0 g, n-pentane 3.5 g, water 0.18 g, polymethylene polyphenyl polyisocyanate 98.5 g.

[0062] Preparation method of xylose-modified polyurethane rigid foam:

[0063] S1 Preparation of xylose liquefied product:

[0064] Add xylose and polyethylene glycol - 400 into a two - necked flask equipped with a stirring and reflux system for liquefaction. Set the temperature at 120 °C, the time at 45 min, and the stirring speed at 500 r / min. Immediately immerse the flask in cold water to cool it to room temperature after the reaction ends, and that's it.

[0065] S2 Preparation of xylose - modified polyurethane rigid foam:

[0066] Add triethylamine, dibutyltin dilaurate, dimethyl silicone oil, n - pentane, and water into the xylose liquefied product obtained in step S1 in sequence, stir for 5 min to obtain a mixed solution. Then add polymethylene polyphenyl polyisocyanate into the mixed solution and continue stirring until the system turns white. Pour the mixture into a mold and let it freely foam at room temperature. After the foam cools to room temperature, put it into an electric blast drying oven at 80 °C for curing for 1 d, take it out and cool to obtain xylose - modified polyurethane rigid foam.

[0067] Example 5

[0068] Formulation of glucose - modified polyurethane rigid foam:

[0069] Glucose 15 g, polyethylene glycol - 400 85 g, triethylamine 0.06 g, dibutyltin dilaurate 0.06 g, dimethyl silicone oil 1.0 g, n - pentane 3.5 g, water 0.18 g, polymethylene polyphenyl polyisocyanate 98.5 g.

[0070] Preparation method of glucose - modified polyurethane rigid foam:

[0071] S1 Preparation of glucose liquefied product:

[0072] Add glucose and polyethylene glycol - 400 into a two - necked flask equipped with a stirring and reflux system for liquefaction. Set the temperature at 120 °C, the time at 45 min, and the stirring speed at 500 r / min. Immediately immerse the flask in cold water to cool it to room temperature after the reaction ends, and that's it.

[0073] S2 Preparation of glucose - modified polyurethane rigid foam:

[0074] Add triethylamine, dibutyltin dilaurate, dimethyl silicone oil, n - pentane, and water into the glucose liquefied product obtained in step S1 in sequence, stir for 5 min to obtain a mixed solution. Then add polymethylene polyphenyl polyisocyanate into the mixed solution and continue stirring until the system turns white. Pour the mixture into a mold and let it freely foam at room temperature. After the foam cools to room temperature, put it into an electric blast drying oven at 80 °C for curing for 1 d, take it out and cool to obtain glucose - modified polyurethane rigid foam.

[0075] Example 6

[0076] Formulation of mixed monosaccharide modified rigid polyurethane foam:

[0077] Xylose 7.5 g, glucose 7.5 g, polyethylene glycol - 400 85 g, triethylamine 0.06 g, dibutyltin dilaurate 0.06 g, dimethyl silicone oil 1.0 g, n - pentane 3.5 g, water 0.18 g, polymethylene polyphenyl polyisocyanate 98.5 g.

[0078] Preparation method of mixed monosaccharide modified rigid polyurethane foam:

[0079] S1 Preparation of mixed monosaccharide liquefied product:

[0080] Add xylose, glucose and polyethylene glycol - 400 into a two - necked flask with a stirring and reflux system for liquefaction. Set the temperature at 120 °C, the time at 45 min, and the stirring speed at 500 r / min. Immediately immerse the flask in cold water to cool it to room temperature after the reaction ends, and it is obtained.

[0081] S2 Preparation of mixed monosaccharide modified rigid polyurethane foam:

[0082] Add triethylamine, dibutyltin dilaurate, dimethyl silicone oil, n - pentane and water into the mixed monosaccharide liquefied product obtained in step S1 in sequence, stir for 5 min to obtain a mixed solution. Then add polymethylene polyphenyl polyisocyanate into the mixed solution and continue stirring until the system turns white. Pour the mixture into a mold and freely foam at room temperature. After the foam cools to room temperature, put it into an electro - thermal blast drying oven at 80 °C for curing for 1 d, and take it out and cool to obtain the mixed monosaccharide modified rigid polyurethane foam.

[0083] In order to further verify the reliability of the present invention, the inventor conducted a series of tests as follows:

[0084] 1. Equipment and materials

[0085] The main reagents and equipment are shown in Table 1.

[0086] Table 1 Main reagents and equipment

[0087]

[0088] 2. Preparation of monosaccharide modified rigid polyurethane foam

[0089] The material prepared in this study is rigid polyurethane foam (PURF), which is mainly used for building thermal insulation boards. The formula of industrial PURF is usually prepared by the reaction of polymethylene polyphenyl polyisocyanate (PAPI) and polyethylene glycol (PEG-400). Some additives will be added during the preparation process, namely the catalysts dibutyltin dilaurate and triethylamine, the blowing agents water and n-pentane, and the foam stabilizer dimethyl silicone oil. The national standards for rigid polyurethane thermal insulation boards are shown in Table 2.

[0090] Table 2 National Standards for Rigid Polyurethane Thermal Insulation Boards

[0091]

[0092] The invention team prepared PURF using the industrial formula and tested its performance indicators. The results are as follows: the density is 117.4 kg / m 3 ; the compressive strength is 0.29768 MPa; the thermal conductivity is 0.0248 W / (m·K), meeting the performance requirements of Class III thermal insulation boards in the national standards.

[0093] To further improve the performance of thermal insulation boards, reduce industrial production costs, and achieve the high-value utilization of biomass resources and reduce dependence on fossil resources. Based on in-depth research, the R & D team used green and renewable monosaccharides (xylose, glucose or a mixture of the two) to replace part of the polyol to prepare rigid polyurethane foam. The formula and preparation method are as follows:

[0094] Formula for monosaccharide-modified rigid polyurethane foam:

[0095] 100 g of polyglycol-400 partially replaced by monosaccharides or the liquefaction product of monosaccharides, 98.5 g of polymethylene polyphenyl polyisocyanate, 0.04 - 0.08 g of triethylamine, 0.04 - 0.08 g of dibutyltin dilaurate, 0.8 - 1.2 g of dimethyl silicone oil, 3 - 4 g of n-pentane, and 0.12 - 0.24 g of water. Among them, in the polyglycol-400 partially replaced by monosaccharides, the substitution rate of monosaccharides for polyglycol-400 is 10 - 20 wt%, and the mass ratio of the catalyst triethylamine to dibutyltin dilaurate is 1:1.

[0096] Preparation method of monosaccharide-modified rigid polyurethane foam:

[0097] (1) Prepare a mixed suspension of polyglycol-400 partially replaced by monosaccharides

[0098] Take monosaccharides (glucose, xylose or a mixture of the two), add them to polyglycol-400, and stir with an electric stirrer at a speed of 1000 r / min for 1 h at room temperature to make the above compounds evenly mixed, thus obtaining it.

[0099] (2) Prepare the liquefaction product of monosaccharides

[0100] Add monosaccharides (glucose, xylose or a mixture of the two) and polyethylene glycol - 400 into a two - necked flask equipped with a stirring and reflux system for liquefaction. Set the temperature at 120 °C, the time at 45 min, and the stirring speed at 500 r / min. Immediately after the reaction, immerse the flask in cold water and cool it to room temperature to obtain the product.

[0101] (3) Preparation of monosaccharide - modified rigid polyurethane foam

[0102] Add triethylamine, dibutyltin dilaurate, dimethyl silicone oil, n - pentane and water successively into the mixed suspension obtained in (1) where monosaccharides partially replace polyethylene glycol - 400 or the monosaccharide liquefaction product obtained in (2), stir for 5 min to obtain a mixed solution. Then add polymethylene polyphenyl polyisocyanate to the mixed solution and continue stirring until the system turns white. Pour the mixture into a mold and let it foam freely at room temperature. After the foam cools to room temperature, place it in an electric blast drying oven at 80 °C for curing for 1 d, take it out and cool to obtain the monosaccharide - modified rigid polyurethane foam.

[0103] 3. Verification of performance indicators of monosaccharide - modified rigid polyurethane foam

[0104] 3.1 Experimental setup

[0105] A total of 13 groups were set up in the method to verify the feasibility of the method, namely Examples 1 - 6 of the present invention and Comparative Examples 1 - 7. The formulations and preparation methods of Comparative Examples 1 - 7 are as follows:

[0106] Comparative Example 1

[0107] Rigid polyurethane foam formulation:

[0108] Polyethylene glycol - 400 100 g, triethylamine 0.08 g, dibutyltin dilaurate 0.08 g, dimethyl silicone oil 1.0 g, n - pentane 3 g, water 0.18 g, polymethylene polyphenyl polyisocyanate 98.5 g.

[0109] Rigid polyurethane foam preparation method:

[0110] Add triethylamine, dibutyltin dilaurate, dimethyl silicone oil, n - pentane and water successively into polyethylene glycol - 400, stir with an electric stirrer at a speed of 1000 r / min for 5 min at room temperature to obtain a mixed solution. Then add polymethylene polyphenyl polyisocyanate to the mixed solution and continue stirring until the system turns white. Pour the mixture into a mold and let it foam freely at room temperature. After the foam cools to room temperature, place it in an electric blast drying oven at 80 °C for curing for 1 d, take it out and cool to obtain the rigid polyurethane foam.

[0111] Comparative Example 2

[0112] Xylose-modified polyurethane rigid foam formula:

[0113] Xylose 10 g, polyethylene glycol - 400 90 g, triethylamine 0.06 g, dibutyltin dilaurate 0.06 g, dimethyl silicone oil 1.0 g, n-pentane 3.5 g, water 0.18 g, polymethylene polyphenyl polyisocyanate 98.5 g.

[0114] Preparation method of xylose-modified polyurethane rigid foam:

[0115] S1 Prepare a mixed suspension with xylose partially replacing polyethylene glycol - 400:

[0116] Take xylose and add it to polyethylene glycol - 400. Stir with an electric stirrer at a speed of 1000 r / min at room temperature for 1 h to make the above compounds mix evenly, and you will get it;

[0117] S2 Prepare xylose-modified polyurethane rigid foam:

[0118] Add triethylamine, dibutyltin dilaurate, dimethyl silicone oil, n-pentane and water to the mixed suspension prepared in step S1 in sequence, stir for 5 min to obtain a mixed solution; then add polymethylene polyphenyl polyisocyanate to the mixed solution and continue to stir until the system turns white; pour the mixture into a mold and freely foam at room temperature; after the foam cools to room temperature, put it into an electric blast drying oven at 80 °C for curing for 1 d, take it out and cool to obtain xylose-modified polyurethane rigid foam.

[0119] Comparative Example 3

[0120] Xylose-modified polyurethane rigid foam formula:

[0121] Xylose 20 g, polyethylene glycol - 400 80 g, triethylamine 0.06 g, dibutyltin dilaurate 0.06 g, dimethyl silicone oil 1.0 g, n-pentane 3.5 g, water 0.18 g, polymethylene polyphenyl polyisocyanate 98.5 g.

[0122] Preparation method of xylose-modified polyurethane rigid foam:

[0123] S1 Prepare a mixed suspension with xylose partially replacing polyethylene glycol - 400:

[0124] Take xylose and add it to polyethylene glycol - 400. Stir with an electric stirrer at a speed of 1000 r / min at room temperature for 1 h to make the above compounds mix evenly, and you will get it;

[0125] S2 Prepare xylose-modified polyurethane rigid foam:

[0126] Triethylamine, dibutyltin dilaurate, dimethyl silicone oil, n-pentane and water were successively added to the mixed suspension prepared in step S1, and stirred for 5 min to obtain a mixed solution; then polymethylene polyphenyl polyisocyanate was added to the mixed solution, and stirring was continued until the system turned white; the mixture was poured into a mold and freely foamed at room temperature; after the foam was cooled to room temperature, it was placed in an electrothermal blast drying oven at 80 °C for curing for 1 day, and then taken out and cooled to obtain xylose-modified polyurethane rigid foam.

[0127] Comparative Example 4

[0128] Xylose-modified polyurethane rigid foam formulation:

[0129] Xylose 15 g, polyethylene glycol-400 85 g, triethylamine 0.06 g, dibutyltin dilaurate 0.06 g, dimethyl silicone oil 0.8 g, n-pentane 3.5 g, water 0.18 g, polymethylene polyphenyl polyisocyanate 98.5 g.

[0130] Preparation method of xylose-modified polyurethane rigid foam:

[0131] S1 Preparation of xylose partially substituting polyethylene glycol-400 mixed suspension:

[0132] Take xylose, add it to polyethylene glycol-400, and stir with an electric stirrer at a speed of 1000 r / min at room temperature for 1 h to make the above compounds mix evenly, thus obtaining it.

[0133] S2 Preparation of xylose-modified polyurethane rigid foam:

[0134] Triethylamine, dibutyltin dilaurate, dimethyl silicone oil, n-pentane and water were successively added to the mixed suspension prepared in step S1, and stirred for 5 min to obtain a mixed solution; then polymethylene polyphenyl polyisocyanate was added to the mixed solution, and stirring was continued until the system turned white; the mixture was poured into a mold and freely foamed at room temperature; after the foam was cooled to room temperature, it was placed in an electrothermal blast drying oven at 80 °C for curing for 1 day, and then taken out and cooled to obtain xylose-modified polyurethane rigid foam.

[0135] Comparative Example 5

[0136] Xylose-modified polyurethane rigid foam formulation:

[0137] Xylose 15 g, polyethylene glycol-400 85 g, triethylamine 0.08 g, dibutyltin dilaurate 0.08 g, dimethyl silicone oil 1.0 g, n-pentane 3.5 g, water 0.18 g, polymethylene polyphenyl polyisocyanate 98.5 g.

[0138] Preparation method of xylose-modified polyurethane rigid foam:

[0139] S1 Preparation of xylose partially substituted polyethylene glycol-400 mixed suspension:

[0140] Take xylose and add it to polyethylene glycol-400. Stir with an electric stirrer at a speed of 1000 r / min for 1 h at room temperature to make the above compounds mix evenly, thus obtaining it.

[0141] S2 Preparation of xylose-modified polyurethane rigid foam:

[0142] Add triethylamine, dibutyltin dilaurate, dimethyl silicone oil, n-pentane and water to the mixed suspension prepared in step S1 in sequence, stir for 5 min to obtain a mixed solution; then add polymethylene polyphenyl polyisocyanate to the mixed solution and continue stirring until the system turns white; pour the mixture into a mold and freely foam at room temperature; after the foam cools to room temperature, place it in an electric blast drying oven at 80 °C for curing for 1 d, take it out and cool to obtain xylose-modified polyurethane rigid foam.

[0143] Comparative Example 6

[0144] Formulation of glucose-modified polyurethane rigid foam:

[0145] Glucose 15 g, polyethylene glycol-400 85 g, triethylamine 0.06 g, dibutyltin dilaurate 0.06 g, dimethyl silicone oil 1.0 g, n-pentane 3 g, water 0.18 g, polymethylene polyphenyl polyisocyanate 98.5 g.

[0146] Preparation method of glucose-modified polyurethane rigid foam:

[0147] S1 Preparation of glucose partially substituted polyethylene glycol-400 mixed suspension:

[0148] Take glucose and add it to polyethylene glycol-400. Stir with an electric stirrer at a speed of 1000 r / min for 1 h at room temperature to make the above compounds mix evenly, thus obtaining it.

[0149] S2 Preparation of glucose-modified polyurethane rigid foam:

[0150] Add triethylamine, dibutyltin dilaurate, dimethyl silicone oil, n-pentane and water to the mixed suspension prepared in step S1 in sequence, stir for 5 min to obtain a mixed solution; then add polymethylene polyphenyl polyisocyanate to the mixed solution and continue stirring until the system turns white; pour the mixture into a mold and freely foam at room temperature; after the foam cools to room temperature, place it in an electric blast drying oven at 80 °C for curing for 1 d, take it out and cool to obtain glucose-modified polyurethane rigid foam.

[0151] Comparative Example 7

[0152] Formulation of maltose-modified polyurethane rigid foam:

[0153] 15 g of maltose, 85 g of polyethylene glycol - 400, 0.06 g of triethylamine, 0.06 g of dibutyltin dilaurate, 1.0 g of dimethyl silicone oil, 3.5 g of n - pentane, 0.18 g of water, 98.5 g of polymethylene polyphenyl polyisocyanate.

[0154] Preparation method of maltose - modified polyurethane rigid foam:

[0155] S1 Preparation of maltose partially substituting polyethylene glycol - 400 mixed suspension:

[0156] Take maltose and add it to polyethylene glycol - 400. Stir with an electric stirrer at a speed of 1000 r / min for 1 h at room temperature to make the above compounds mix evenly, then it is obtained.

[0157] S2 Preparation of maltose - modified polyurethane rigid foam:

[0158] Add triethylamine, dibutyltin dilaurate, dimethyl silicone oil, n - pentane and water to the mixed suspension prepared in step S1 in sequence, stir for 5 min to obtain a mixed solution; then add polymethylene polyphenyl polyisocyanate to the mixed solution and continue stirring until the system turns white; pour the mixture into a mold and let it freely foam at room temperature; after the foam cools to room temperature, put it into an electro - thermal blast drying oven at 80 °C for curing for 1 d, and take it out and cool to obtain maltose - modified polyurethane rigid foam.

[0159] 3.2 Results and analysis

[0160] Prepare polyurethane rigid foam according to the methods in Examples 1 - 6 and Comparative Examples 1 - 7, and test their performance indexes respectively. The results are shown in Table 3. The PU morphology diagram in Example 1 is as Figure 1 shown, and the PU morphology diagrams in Comparative Examples 3 - 7 are as Figures 2 - 6 shown.

[0161] Table 3 Performance test results of modified polyurethane rigid foam

[0162]

[0163]

[0164] As can be seen from the above table, in this study, monosaccharides, polyols, and polyisocyanates were used as basic raw materials, and foaming aids were added to prepare a series of monosaccharide - modified polyurethane rigid foams with high mechanical strength and excellent heat - insulation performance. The test results show that the monosaccharide - modified polyurethane foams prepared in this study all have a relatively low thermal conductivity, and the thermal conductivity range is 0.0074 - 0.0187 W / (m·K).

[0165] Compared with Example 1, in Example 2, glucose was selected as the reaction raw material to replace part of the polyol to prepare the monosaccharide-modified rigid polyurethane foam. Compared with using xylose as the reaction raw material to replace part of the polyol to prepare the monosaccharide-modified rigid polyurethane foam in Example 1, its thermal conductivity increased significantly, and the density and compressive strength changed less. It can be seen that the rigid polyurethane foam prepared using xylose as the raw material can obtain better heat insulation performance.

[0166] Compared with Comparative Example 1, Examples 1 and 2 show that the heat insulation performance of the polyurethane foam prepared using xylose or glucose as the raw material is significantly improved compared to the pure polyurethane foam. It can be seen that the polyurethane foams prepared by monosaccharide modification all have excellent heat insulation performance.

[0167] Compared with Example 1, in Example 4, the polyol is the liquefied product of xylose. Although the heat insulation performance in Example 4 is slightly lower than that in Example 1, compared with the traditional rigid polyurethane foam prepared in Comparative Example 1, its heat insulation performance is still significantly improved.

[0168] The density and compressive strength of the rigid polyurethane foam in Example 6 can reach 105.47 kg / m 3 and 0.35228 MPa. This is because liquefying xylose can increase the reaction contact area and improve the reaction activity, making the cell structure more regular and thus enhancing the mechanical strength of the foam.

[0169] Compared with Example 1, in Comparative Example 2, the substitution rate of the polyol is 10 wt%. The thermal conductivity of the polyurethane foam increases significantly, and the density and compressive strength also increase to some extent. This is because less xylose is added, and it is more inclined to act as a filler in the system to enhance the mechanical properties.

[0170] Compared with Example 1, in Comparative Example 3, the substitution rate of the polyol is 20 wt%. The thermal conductivity of the polyurethane foam increases to some extent, and the compressive strength decreases significantly. From Figure 2 it can be seen that there is obvious xylose residue on the cell surface. This is because too much xylose is added. Part of the xylose participates in the polymerization reaction, and the other part of the xylose destroys the uniformity of the cell formation during the foaming process, resulting in a decrease in the compressive strength of the foam.

[0171] In Example 1 and Comparative Example 4, the addition amounts of dimethyl silicone oil are 0.8 g and 1.0 g respectively, and the other conditions are the same. Compared with Example 1, the thermal conductivity in Comparative Example 4 increases significantly. This is because dimethyl silicone oil can reduce the surface tension of the reaction system and increase the cell wall thickness to control the cell uniformity. When the addition amount of silicone oil decreases, it is not conducive to the subsequent reaction and polymerization of the mixed suspension with polyisocyanate. From Figure 3 it can be seen that the cell uniformity decreases and the closed cell rate decreases, resulting in a decrease in the heat insulation performance of the foam.

[0172] In Comparative Example 5 and Example 1, the catalyst addition amounts were 0.08 g and 0.06 g respectively, and the other conditions were the same. Compared with Example 1, the mechanical properties and heat preservation performance of Comparative Example 5 both decreased. This is because the two catalysts respectively catalyze the foaming and cross-linking reactions during the polymerization process. It can be seen from Figure 4 this that excessive catalyst will lead to an unbalanced foaming process, resulting in uneven cell pores and a decrease in the closed cell rate of the foam.

[0173] In Comparative Example 6 and Example 2, the addition amounts of the foaming agent n-pentane were 3.0 g and 3.5 g respectively, and the other conditions were the same. Compared with Example 2, the compressive strength of Comparative Example 6 increased, but the heat preservation performance decreased. This is because n-pentane, as a physical foaming agent, absorbs the heat during the polymerization reaction and gasifies itself, thereby causing the polyurethane to foam and form a foam. It can be seen from Figure 5 this that when the addition amount is relatively low, it will cause the cell walls of the foam to shrink and the volume to become smaller, thereby reducing the heat preservation performance of the foam.

[0174] Compared with Example 2, in Comparative Example 7, maltose is a glucose disaccharide, and the compressive strength of the prepared polyurethane foam decreased significantly, and the thermal conductivity increased slightly compared with Example 1. It can be clearly seen from Figure 6 this that large-scale cavities appeared in the cell pores and the surface showed a tendency of collapse. This is because the reaction steric hindrance of disaccharides is greater than that of monosaccharides, and the water solubility of maltose is lower than that of glucose, which is not conducive to the polymerization reaction with polyisocyanate. It can be seen that the polyurethane rigid foam prepared by using monosaccharides in the present invention has better heat preservation performance than the polyurethane rigid foam prepared by using disaccharides.

[0175] In summary, in this study, a series of monosaccharide-modified polyurethane rigid foams with high mechanical strength and excellent heat preservation performance were prepared by using biomass hydrolysis product monosaccharides to partially replace polyols and polymethylene polyphenyl polyisocyanates. Among them, when using xylose to partially replace polyethylene glycol-400 as the raw material and the xylose replacement rate is 15 wt%, the heat preservation performance of the prepared xylose-modified polyurethane rigid foam is the best, and its thermal conductivity is only 0.0074 W / (m·K). The performance indexes of the polyurethane rigid foam prepared in this study are higher than the requirements of Class III rigid polyurethane foam for building thermal insulation in GB / T 21558-2008 and are more environmentally friendly, having great market application prospects.

[0176] Although the present invention has been described in detail above with general descriptions, specific embodiments and experiments, based on the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A monosaccharide modified polyurethane rigid foam, characterized in that: The invention comprises the following components by weight: 100 parts of polyethylene glycol-400 or monosaccharide liquefied product partially replaced by monosaccharide, 98.5 parts of polymethylene polyphenyl polyisocyanate, 0.04-0.08 parts of triethylamine, 0.04-0.08 parts of dibutyltin dilaurate, 0.8-1.2 parts of dimethyl silicone oil, 3.0-4.0 parts of n-pentane, and 0.12-0.24 parts of water; The monosaccharide is any one or both of xylose and glucose; In the polyethylene glycol-400 partially replaced by monosaccharide, the substitution rate of monosaccharide for polyethylene glycol-400 is 10-20wt%; The monosaccharide liquefied product is prepared by adding monosaccharide and polyethylene glycol-400 into a two-necked flask with a stirring and reflux system for liquefaction and then cooling to room temperature.

2. The monosaccharide-modified polyurethane rigid foam according to claim 1, characterized in that: The monosaccharide is xylose.

3. The monosaccharide modified polyurethane rigid foam according to claim 1, characterized in that: In the polyethylene glycol-400 partially replaced by monosaccharide, the substitution rate of monosaccharide for polyethylene glycol-400 is 15-20wt%.

4. The monosaccharide modified polyurethane rigid foam according to claim 3, characterized in that: In the polyethylene glycol-400 partially replaced by monosaccharide, the substitution rate of monosaccharide for polyethylene glycol-400 is 15wt%.

5. The monosaccharide modified polyurethane rigid foam according to claim 1, characterized in that: The monosaccharide liquefaction product is prepared by adding monosaccharide and polyethylene glycol-400 with a mass ratio of 15:85 into a two-necked flask with a stirring and reflux system for liquefaction, setting the temperature to 120°C, the reaction time to 45 minutes, and the stirring speed to 500 r / min; after the reaction is completed, the flask is immediately immersed in cold water and cooled to room temperature.

6. The monosaccharide modified polyurethane rigid foam according to claim 1, characterized in that: The triethylamine is 0.06 parts by mass; the dibutyltin dilaurate is 0.06 parts by mass; the mass ratio of the triethylamine to the dibutyltin dilaurate is 1:1; the dimethyl silicone oil is 1 part by mass; and the n-pentane is 3.5 parts by mass; The water is 0.18 parts by mass.

7. The method for preparing the monosaccharide modified polyurethane rigid foam according to claim 1, characterized in that: The steps include: S1: preparing a mixed suspension of monosaccharide partially replacing polyethylene glycol-400 or a monosaccharide liquefied product; wherein the method for preparing the mixed suspension of monosaccharide partially replacing polyethylene glycol-400 is: adding monosaccharide to polyethylene glycol-400, stirring at room temperature, and obtaining the mixture; S2 prepares monosaccharide-modified polyurethane rigid foam: triethylamine, dibutyltin dilaurate, dimethyl silicone oil, n-pentane and water are sequentially added to the monosaccharide partially replaced polyethylene glycol-400 mixed suspension or monosaccharide liquefaction product prepared in step S1, and stirred for 5 minutes to obtain a mixed solution; polymethylene polyphenyl polyisocyanate is then added to the mixed solution, and stirring is continued until the system turns white; the mixture is poured into a mold and freely foamed at room temperature; after the foam is cooled to room temperature, it is placed in an electric heated forced air drying oven for maturation, and taken out and cooled to obtain the foam.

8. The method for preparing the monosaccharide-modified polyurethane rigid foam according to claim 7, characterized in that: The stirring speed of the stirring at room temperature in step S1 is 1000 r / min, and the stirring time is 1 h.

9. The method for preparing the monosaccharide modified polyurethane rigid foam according to claim 7, characterized in that: The aging temperature in step S2 is 80° C. and the aging time is 1 hour.

10. Use of the monosaccharide modified polyurethane rigid foam according to claim 1 in preparing thermal insulation boards for building thermal insulation.

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