Preparation method of polyurethane sponge with high mechanical strength and high biomass content

Abstract

The invention discloses a preparation method of polyurethane sponge with high mechanical strength and high biomass content. The sponge is prepared from pure biomass polyol, a polyurethane cross-linking chain extender, a pore opening agent, foaming agent water, an organosilicon foam stabilizer, a reaction catalyst and isocyanate. The density is greater than 50kg / m < 3 >, the biomass content is greater than 75%, the tear strength is greater than 5N / cm, and the tensile strength is greater than 0.25 N / mm < 2 >. During preparation, in a polyurethane sponge foaming standard formula, pure biomass polyol accounts for 100% of the total amount of polyol in the formula; according to the standard formula, 0-3 parts of a polyurethane cross-linking chain extender, 1-4 parts of a pore opening agent, 1-2 parts of foaming agent water, 0.6-1.2 parts of a reaction catalyst and 28-40 parts of isocyanate are adopted, an intermittent mold casting method is adopted and comprises two modes of manual casting foaming and semi-automatic casting foaming, the temperature of raw materials is controlled to be 20-25 DEG C in the foaming process, the curing time in a natural ventilation environment after mold stripping is not less than 48 hours, and the foaming temperature is controlled to be 20-25 DEG C; the polyurethane sponge disclosed by the invention has the advantages of environmental friendliness, excellent performance, simplicity and convenience in preparation, stable quality and the like.

Description

Technical Field

[0001] The invention belongs to the technical field related to biomass sponges with high biomass content, and specifically relates to a method for preparing a polyurethane sponge with high mechanical strength and high biomass content. Background Art

[0002] Ordinary soft polyurethane sponge is made by chemically synthesized petroleum polyols, which react with isocyanate in the presence of catalysts, foaming agents, foam stabilizers and other additives to produce a chemical foaming reaction. This type of sponge uses petroleum-based polyols as its raw material, which is extremely difficult to degrade naturally in the natural environment. Therefore, it will cause white environmental pollution. Also, due to its limited resources, it cannot be produced sustainably.

[0003] Density ≥50Kg / m 3 Ordinary polyurethane sponge has poor mechanical strength. Its tear strength is generally ≤5N / cm and its tensile strength is generally ≤0.25N / mm 2 Therefore, ordinary petroleum-based polyurethane sponge cannot be used in products that require high tear and tensile strength and good wear resistance, thus limiting its scope of use; ordinary petroleum-based polyurethane sponge has poor mechanical strength and short service life, which is bound to cause serious waste of natural resources and serious damage to the natural environment on which human beings depend for survival. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a polyurethane sponge with high mechanical strength and high biomass content, so as to solve the problems of insufficient mechanical strength and difficulty in natural degradation of ordinary petroleum-based polyurethane sponges mentioned in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A biomass polyurethane sponge with high mechanical strength and high biomass content is prepared from pure biomass polyol, polyurethane cross-linking chain extender, polyurethane foam cell opener, foaming agent water, organosilicon foam stabilizer, reaction catalyst and isocyanate.

[0007] Preferably, the density of the sponge is greater than 50 kg / m 3 , biomass content greater than 75%, tear strength greater than 5N / cm, tensile strength greater than 0.25N / mm 2 .

[0008] Preferably, the biomass content of the pure biomass polyol is greater than 99.5%, the average molecular weight is 2000, the functionality is 2, and it accounts for 100% of the raw material polyol in the entire sponge foaming standard formula.

[0009] Preferably, the polyurethane cross-linking chain extender is a small molecule biomass diol, and the amount added in the foaming standard formula is 0-3% of the pure biomass diol.

[0010] Preferably, the polyurethane foam cell opener is added in an amount of 1-4% based on 100 parts of pure biomass polyol in the standard foaming formula.

[0011] Preferably, the amount of water as a foaming agent added in the standard foaming formula is 1-2% based on 100 parts of pure biomass alcohol.

[0012] Preferred reaction catalysts include amine catalysts and organotin catalysts, and the amount added in the standard foaming formula is 0.6-1.2% based on 100 parts of pure biomass alcohol.

[0013] Preferably, the isocyanate is one or two of toluene diisocyanate TDI / 80-20 and TDI / 65-35, and the amount added in the standard foaming formula is 28-40% of 100 parts of pure biomass polyol.

[0014] Preferably, the preparation method of the sponge adopts an intermittent mold pouring foaming method, including manual pouring foaming and semi-automatic pouring foaming. During the foaming process, the material temperature of all raw materials is always controlled at 20-25°C; the sponge after foaming and molding needs to be placed in a natural ventilation and heat dissipation environment for maturation, and the maturation time is not less than 48 hours.

[0015] Preferably, the specific steps of the sponge preparation method are as follows:

[0016] S1. Raw material preparation

[0017] According to the mass fraction ratio of biomass polyol in the standard foaming formula, according to the size of the mold, the density of the sponge, the hardness of the sponge, etc., a certain weight of pure biomass polyol is weighed, and the biomass content of the biomass polyol is ≥99.5%, the average molecular weight is 2000, and the functionality is 2;

[0018] Weigh 0-3% polyurethane crosslinking extender based on the weight of pure biomass polyol, the crosslinking extender is a small molecule biomass diol, and its biomass content is ≥99.5%;

[0019] Weigh 1-4% of the weight of the pure biomass polyol as a polyurethane foam cell opener;

[0020] Weigh 1-2% of the weight of pure biomass polyol as a blowing agent water;

[0021] Weigh 1-4% of the weight of the polyurethane cell opener based on the weight of the pure biomass polyol;

[0022] Weigh 0.8-1.5% of the weight of pure biomass polyol as silicone foam stabilizer;

[0023] Weigh 0.6-1.2% of the weight of pure biomass polyol as a reaction catalyst, including an amine catalyst and an organotin catalyst;

[0024] Weigh 28-40% of the weight of pure biomass polyol in one or two of toluene diisocyanate TDI-80 / 20 and TDI-65 / 35;

[0025] S2, manual pouring foaming

[0026] According to the mass ratio of each raw material in the standard polyurethane foaming formula, the density of the sponge, the size of the mold, etc., a certain amount of biomass polyol, crosslinking chain extender, foaming agent, cell opener, foam stabilizer and reaction catalyst are weighed and then added to the mixing container in sequence;

[0027] First, use an electric stirring rod with a stirring blade to stir at a low speed of about 300 rpm for about 5-10 minutes to fully mix the components;

[0028] Then, the weighed isocyanate is quickly put into the mixing container, and then stirred at a speed of about 3000 rpm for about 3-5 seconds;

[0029] Finally, pour all the mixture into the mold quickly and let it foam;

[0030] S3, semi-automatic pouring and foaming

[0031] Through precision metering pumps, the mass ratios of various raw materials in the standard formula are converted into flow ratios, and are almost simultaneously and continuously input from different storage tanks through different delivery pipelines into the high-speed mixing head for mixing and stirring;

[0032] Then it is poured into the mold through the output pipeline on the mixing head for foaming. The total pouring volume of the mixture is different for molds of different density, hardness and size. The pouring volume is controlled by the flow rate and the length of pouring time.

[0033] S4. Ripening

[0034] Whether it is manual pouring foaming or semi-automatic pouring foaming, the sponge after molded must be placed in a natural ventilation and heat dissipation environment for maturation, and the maturation time should be no less than 48 hours;

[0035] S5. Cutting and subsequent processing

[0036] After the sponge is fully matured, it can be cut and processed to obtain the final product.

[0037] It should be noted that during the entire preparation process, the material temperature of all raw materials must always be controlled at 20-25°C.

[0038] Compared with the prior art, the present invention provides a method for preparing a polyurethane sponge with high mechanical strength and high biomass content, which has the following beneficial effects:

[0039] Environmentally friendly: High biomass content reduces dependence on non-renewable resources such as oil, reduces white pollution, and is conducive to environmental protection and sustainable development;

[0040] Excellent mechanical properties: tear strength greater than 5N / cm and greater than 0.25N / mm 2 The tensile strength can meet the use requirements of products with high tear resistance, tensile strength and good wear resistance, which expands the application range of sponges and can be widely used in household, underwear, cleaning, washing, grinding and polishing, automotive interior and other materials;

[0041] High quality and high stability: good foam structure and appearance flatness improve the quality and stability of the product;

[0042] Customized flexibility: By adjusting the ratio of raw materials, sponges with different densities and properties can be prepared to meet diverse market needs;

[0043] High efficiency and energy saving: Optimized foaming process and raw material combination improve energy efficiency and reduce production costs;

[0044] Convenient post-processing: Long pouring operation time and good leveling make the production process easier to control and operate;

[0045] Long-term reliable performance: Long aging time and high-quality raw material selection ensure the long-term performance and stability of the sponge and extend its service life;

[0046] Safety and health: The raw materials and preparation process used are relatively environmentally friendly, reducing potential harm to human health and the environment. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] The present invention provides a technical solution:

[0049] A polyurethane sponge with high mechanical strength and high biomass content is prepared from pure biomass polyol, a polyurethane cross-linking chain extender, a polyurethane foam cell opener, foaming agent water, an organosilicon foam stabilizer, a reaction catalyst and isocyanate.

[0050] The density of the sponge is greater than 50kg / m 3 , biomass content greater than 75%, tear strength greater than 5N / cm, tensile strength greater than 0.25N / mm 2 .

[0051] The biomass content of pure biomass polyol is greater than 99.5%, the average molecular weight is 2000, the functionality is 2, and in the standard polyurethane foaming formula, it accounts for 100% of all polyol raw materials.

[0052] The polyurethane cross-linking chain extender is a small molecule biomass diol, which accounts for 0-3% of the biomass diol in the standard formula.

[0053] Polyurethane foam cell opener, accounting for 1-4% of biomass alcohol in standard formulation.

[0054] Foaming agent water accounts for 1-2% of biomass alcohol in the standard formula.

[0055] The reaction catalyst comprises an amine catalyst and an organic tin catalyst, and the total mass accounts for 0.6-1.2% of the biomass alcohol in the standard formula.

[0056] The isocyanate is one or two of toluene diisocyanate TDI-80 / 20 and TDI-65 / 35, and the total mass of the isocyanate accounts for 28-40% of the biomass polyol in the standard formula.

[0057] The preparation method of high mechanical strength and high biomass content polyurethane sponge adopts intermittent mold casting method, including manual pouring foaming and semi-automatic pouring foaming. During the foaming process, the material temperature of all raw materials is always controlled at 20-25°C; the sponge after foaming and molding needs to be placed in a natural ventilation and heat dissipation environment for maturation, and the maturation time is not less than 48 hours.

[0058] ① Pure biomass polyol: EV-2056, a 2000 molecular weight, bifunctional pure biomass polyol, derived from plant oils and fats, with a biomass content of ≥99.5%, accounting for 100% of the polyol in the standard polyurethane sponge foaming formula;

[0059] ②Polyurethane pore opener: milky white pore opener K8113, BMD-4; transparent pore opener K4900, sK1900, etc., can be used alone or in combination. The total amount of pore opener is 1-4% of biomass diol EV-2056. The specific amount depends on the pore opening effect of the pore opener. In principle, it is necessary to ensure that the sponge is pore-opened, does not shrink, and does not step on bubbles;

[0060] ③ Foaming agent water, water reacts with toluene diisocyanate to generate polyurethane, while releasing CO2 gas, which takes away the reaction heat of sponge foaming, ensuring safe foaming. CO2 gas expands due to heat, which can stretch the foam body and reduce the density of the sponge. That is, the amount of water can determine the density of the sponge; the density range of the polyurethane sponge of the present invention is ≥50kg / m 3 , and the water content of EV-2056 is about 0.5%, so in the standard formula of the polyurethane sponge with high mechanical strength and high biomass content of the present invention, the number of parts of the foaming agent water used is ≤1.5.

[0061] ④Polyurethane chain extender and crosslinker: biomass low molecular weight diol or biomass low molecular weight triol, such as biomass ethylene glycol, biomass 1,3 propylene glycol, etc., the mass fraction of which is 2-3% of the biomass polyol EV-2056;

[0062] ⑤ Organic silicon foam stabilizer, organic silicon foam stabilizer is mainly composed of surfactant and organic silicon compound. When preparing foam, the role of stabilizer is to form a thin film covering the surface of bubbles to prevent bubbles from bursting and maintain the stability of foam. Since the foaming reaction activity of this biomass sponge is relatively high, low-activity silicone oil such as B-8002 and L-3002 is used. The amount used is about 0.8-1.5% of biomass polyol EV-2056;

[0063] ⑥ The reaction catalysts include amine catalysts and organotin catalysts. There are many varieties of ammonia catalysts. Because the reaction activity of pure biomass diol EV-2056 is relatively special, that is, the reaction rate of EV-2056 with TDI is much slower than the reaction rate of water with TDl, that is, the foaming reaction rate is much faster than the gel reaction rate of biomass diol EV-2056 with TDl, so the amine polyurethane catalyst E300 and delayed ammonia catalyst A300 with strong gel function are used, and the mass fraction is about 0.6-1% of the biomass diol EV-2065. Although organotin has a strong gel effect on the polyurethane reaction, it has a narrow use tolerance and is easy to cause sponge closed cell shrinkage. Therefore, it accounts for a small proportion of the catalyst used in the entire formula, and its amount is generally less than 0.2% of the biomass diol EV-2056;

[0064] ⑦ Toluene diisocyanate TDI, including two isomers TDI / 80-20 and TDI / 65-35. The activity of TDl / 80-20 is slightly higher than that of TDⅠ / 65-35. Since the foaming reaction is characterized by a fast reaction in the early stage and slow maturation in the later stage, some isomers TDI / 65-35 are added to slow down the initial reaction to obtain a longer pouring operation time, which is conducive to the full leveling of the poured mixture in the mold, and the obtained foam structure is better and the appearance is smoother. The amount of TDl in the foaming formula is about 28-40% of the biomass diol EV-2056. The specific amount is determined according to the sponge density and hardness, that is, the foaming index and TDl index; manual / semi-automatic pouring foaming Specific embodiment:

[0066]

[0067]

[0068] Technical description:

[0069] a) The above table and content are the raw material names and standard formulas corresponding to different specific embodiments 1, 2, 3, and 4, as well as the density, tear strength, tensile strength, and biomass content test results of the sponges prepared in each specific embodiment. The sponge density, tear strength, and tensile strength are tested according to the ASTM D3574 test standard and method; the biomass content is tested according to the ASTM D6866 standard and method, which uses the radioactive carbon-14 method to test the product.

[0070] b) The water content in the specific embodiments 1, 2, 3, and 4 does not include the water content in the biomass diol EV-2056. The water content of the biomass diol EV-2056 is about 0.5%, which has been included in the mass fraction of the foaming agent water when designing the sponge density and TDl dosage.

[0071] c) A300 is an amine catalyst with delayed foaming and strong gelling effect. With it as a catalyst, the foaming reaction of polyurethane is slow in the early stage and matures quickly in the later stage, so a longer pouring time can be obtained for the mixture, which is conducive to the full leveling of the mixture in the mold; the sponge prepared with it as a catalyst also matures quickly in the later stage, and the prepared sponge is more open. E300 is a new type of polyurethane chain extender, curing agent and cross-linking agent, which is a mixture of two isomers of 2,4- and 2,6-dimethylthiotoluenediamine. It can greatly improve the problem of difficult late-stage maturation of biomass polyurethane sponge, and can improve the mechanical properties and foaming efficiency of biomass sponge.

[0072] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A polyurethane sponge with high mechanical strength and high biomass content, characterized in that: The polyurethane sponge is made of pure biomass polyol, polyurethane cross-linking chain extender, polyurethane foam cell opener, foaming agent water, organic silicon foam stabilizer, reaction catalyst and isocyanate.

2. A polyurethane sponge with high mechanical strength and high biomass content according to claim 1, characterized in that: The density of the sponge is greater than 50kg / m 3 , biomass content greater than 75%, tear strength greater than 5N / cm, tensile strength greater than 0.25N / mm 2 .

3. A polyurethane sponge with high mechanical strength and high biomass content according to claim 1, characterized in that: The biomass polyol used has a biomass content of ≥99.5%, an average molecular weight of 2000, a functionality of 2, and accounts for 100% of the total mass of the polyol in the standard polyurethane sponge foaming formula.

4. A polyurethane sponge with high mechanical strength and high biomass content according to claim 1, characterized in that: The polyurethane cross-linking chain extender is a small molecule biomass diol, and its mass fraction in the raw material is 0-3 parts.

5. A polyurethane sponge with high mechanical strength and high biomass content according to claim 1, characterized in that: The mass fraction of the polyurethane foam cell opener in the raw materials is 1-4 parts.

6. A polyurethane sponge with high mechanical strength and high biomass content according to claim 1, characterized in that: The mass fraction of foaming agent water in the raw materials is 1-2 parts.

7. A polyurethane sponge with high mechanical strength and high biomass content according to claim 1, characterized in that: The reaction catalyst comprises an amine catalyst and an organotin catalyst, and the total weight fraction thereof is 0.6-1.2 parts.

8. The polyurethane sponge with high mechanical strength and high biomass content according to claim 1, characterized in that: The isocyanate is one or two of toluene diisocyanate TDI-80 / 20 and TDI-65 / 35, and its mass fraction in the raw material is 28-40 parts.

9. A method for preparing a polyurethane sponge with high mechanical strength and high biomass content according to any one of claims 1 to 8, characterized in that: The preparation method of the sponge adopts an intermittent mold pouring method, including manual pouring foaming and semi-automatic pouring foaming. During the foaming process, the material temperature of all raw materials is always controlled at 20-25°C; the sponge after foaming and molding needs to be placed in a natural ventilation and heat dissipation environment for maturation, and the maturation time is not less than 48 hours.

10. The method for preparing a polyurethane sponge with high mechanical strength and high biomass content according to claim 9, characterized in that: The above-mentioned sponge preparation method has the following specific steps: S1. Raw material preparation Weigh pure biomass polyol according to mass fraction, wherein the biomass content is ≥ 99.5%, the average molecular weight is 2000, the functionality is 2, and the mass fraction is 100 parts; Weigh 0-3 parts by weight of a polyurethane cross-linking chain extender, which is a small molecule biomass diol; Weigh 1-4 parts by weight of a polyurethane foam cell opener; Weigh 1-2 parts by mass of foaming agent water; Weigh 0.8-1.5 parts by mass of an organosilicon foam stabilizer; Weigh 0.6-1.2 parts by weight of reaction catalyst, including amine catalyst and organotin catalyst; Weigh 28-40 parts by mass of isocyanate, which is one or two of toluene diisocyanate TDI-80 / 20 and TDI-65 / 35; S2, manual pouring foaming Add weighed biomass polyol, crosslinking chain extender, foaming agent, cell opener, foam stabilizer and reaction catalyst into a mixing container in sequence; First, use an electric stirring rod with a stirring blade to stir at a low speed of about 300 rpm for about 5-10 minutes to fully mix the components; Then, the weighed isocyanate is quickly put into the mixing container, and then stirred at a speed of about 3000 rpm for about 3-5 seconds; Finally, pour the entire mixture cleanly and quickly into the mold and let it foam; S3, semi-automatic pouring and foaming Various raw materials are fed from their respective storage tanks through their respective delivery pipelines almost simultaneously and continuously into the high-speed mixing head for mixing and stirring; Then pour it into the mold through the output pipeline on the mixing head for foaming. The amount of raw materials poured into each mold is controlled according to the size of the mold and the density of the sponge, the flow rate of the mixed material output, and the pouring time; S4. Ripening Whether it is manual pouring foaming or semi-automatic pouring foaming, the sponge after molded must be placed in a natural ventilation and heat dissipation environment for maturation, and the maturation time should be no less than 48 hours; S5. Cutting and subsequent processing After the sponge is fully matured, it can be cut and processed in other ways to obtain the final product. It should be noted that during the entire preparation process, the material temperature of all raw materials must always be controlled at 20-25°C.

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