A kind of organic silicon foam and preparation method thereof

Abstract

The invention discloses a kind of organosilicon foam and its preparation method, and relates to the technical field of foam materials. When preparing organosilicon foam, the present invention reacts octamethylcyclotetrasiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane and trifluoropropylmethylcyclotrisiloxane to obtain functionalized polysiloxane; diallyl chlorophosphite and 4-aminomethyl-2,2,6,6-tetramethylpiperidine are reacted to obtain phosphorus-containing monomer; tetraethyl orthosilicate and sodium metaaluminate are reacted to obtain microporous molecular sieve, and then acid treatment is used to obtain macroporous molecular sieve, and then silane coupling agent is grafted and reacted with tetramethylguanidine to obtain antibacterial macroporous molecular sieve; finally, pure water is used as a foaming agent, diphenylmethane diisocyanate, functionalized polysiloxane, phosphorus-containing monomer, 2,2-dihydroxymethylbutyric acid and antibacterial macroporous molecular sieve are foamed in one step to obtain organosilicon foam. The organosilicon foam prepared by the present invention has high strength, excellent anti-aging performance, flame retardant performance and antibacterial performance.

Description

Technical Field

[0001] The invention relates to the technical field of foam materials, in particular to an organosilicon foam and a preparation method thereof. Background Art

[0002] Silicone foam is a foam product based on silicone, which has many unique properties, such as high and low temperature resistance, excellent electrical insulation, and good strength. These properties make it an ideal material choice in industries such as aerospace, construction, electronics and medical.

[0003] Although silicone foam has many unique properties, it also has some disadvantages, such as the lack of antibacterial function, which limits its application in situations where antibacterial or antimicrobial properties are required; at the same time, although the aging resistance of silicone foam is good, its performance may gradually deteriorate in harsh environments such as high temperature or ultraviolet radiation; in addition, it is not flame retardant and is easy to burn when encountering open flames, creating safety hazards. At the same time, the noise reduction and anti-seismic effects of silicone foam are average. Therefore, the preparation of multifunctional silicone foam can broaden its application field. The silicone foam prepared by the present invention has high strength, excellent anti-aging properties, flame retardant properties, antibacterial and shock-absorbing and noise-reducing properties. Summary of the invention

[0004] The purpose of the present invention is to provide a silicone foam and a preparation method thereof to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A method for preparing silicone foam comprises the following steps:

[0007] (1) Octamethylcyclotetrasiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane and trifluoropropyltrimethylcyclotrisiloxane are mixed uniformly in a mass ratio of 1:0.8-1:2.0-2.5, heated to 80-90°C under nitrogen protection, stirred for 30-40 min at a stirring speed of 400-500 r / min, and then heated to 110-120°C, 0.02-0.03% of the mass of octamethylcyclotetrasiloxane in a 25wt% tetramethylammonium hydroxide aqueous solution is added, and then 0.3-0.4% of the mass of octamethylcyclotetrasiloxane in pure water is added, and the mixture is stirred for 3-4h, heated to 150°C, reacted for 3-4h, and decompressed to 2-2.5Kpa, and reacted for 3-4h to obtain a functionalized polysiloxane;

[0008] (2) Diallyl chlorophosphite, 4-aminomethyl-2,2,6,6-tetramethylpiperidine and dichloromethane are mixed uniformly in a mass ratio of 1:1-1.2:50-60, and triethylamine in an amount of 0.3-0.4 times the mass of diallyl chlorophosphite is added under nitrogen protection, reacting at room temperature for 22-24 hours, filtering and washing with dichloromethane for 3-4 times, and then washing with saturated sodium bicarbonate for 3-4 times, and drying under vacuum at room temperature for 22-24 hours with a vacuum degree of 0.08 MPa to obtain a phosphorus-containing monomer;

[0009] (3) Aluminum isopropoxide and 1 mol / L sodium hydroxide aqueous solution were mixed and stirred at a mass volume ratio of 1:1000-1500 for 1-2 hours at a stirring speed of 200-300 r / min, and then tetrapropylammonium hydroxide was added and stirred for 1-2 hours, and ethyl orthosilicate was slowly added dropwise at a rate of 2 mL / min. After the addition was completed, stirring was continued for 1-2 hours, and urea was added and stirred for 11-12 hours. The reaction system was transferred to a polytetrafluoroethylene reactor, reacted at 180°C for 22-24 hours, filtered, washed with pure water for 6-8 times, and dried in a vacuum drying oven for 6-8 hours to obtain a microporous molecular sieve;

[0010] (4) The macroporous molecular sieve obtained after the acid treatment of the microporous molecular sieve, 3-chloropropyltrimethoxysilane and anhydrous ethanol are mixed uniformly in a mass ratio of 1:1.5-2:50-60, stirred at 200-300 r / min for 22-24 hours, then ultrasonicated at 20-40 kHz for 20-30 minutes, filtered and washed with ethanol 3-4 times, then washed with pure water 3-4 times, redispersed in xylene with an equal volume of anhydrous ethanol, added with tetramethylguanidine with a mass of 0.6-0.8 times of 3-chloropropyltrimethoxysilane, heated to 100-120°C, stirred for 3-4 hours at a stirring speed of 300-400 r / min, cooled to room temperature, filtered and washed with pure water 3-4 times, and dried at 50-60°C for 6-8 hours to obtain an antibacterial macroporous molecular sieve;

[0011] (5) Weigh polyether polyol, functionalized polysiloxane, 2,2-dihydroxymethylbutyric acid, pure water, dibutyltin dilaurate, triethylenediamine and antibacterial macroporous molecular sieve, stir at a stirring speed of 500-600 r / min for 20-30 min, add diphenylmethane diisocyanate and phosphorus-containing monomer at 3000 rpm / min, stir for 10-20 s, pour into a mold preheated to 80-90°C, cure at 80°C for 3-4 h, and then heat to 110-120°C for 2-3 h to obtain silicone foam.

[0012] As an optimization, the weighed amounts of the reagents in step (3) are, by mole, 1-2 parts of aluminum isopropoxide, 10-12 parts of tetrapropylammonium hydroxide, 50-55 parts of tetraethyl orthosilicate, and 40-42 parts of urea.

[0013] As an optimization, the specific steps of obtaining the macroporous molecular sieve by acid treatment of the microporous molecular sieve in step (4) are as follows: uniformly mixing the microporous molecular sieve and 1 mol / L hydrochloric acid aqueous solution at a mass volume ratio of 1:20-30, heating to 60-70°C, continuing to stir the reaction for 1-2h at a stirring speed of 500-600r / min, filtering and washing with pure water for 6-8 times, and drying in a vacuum drying oven at a vacuum degree of 0.08MPa for 6-8h to obtain the macroporous molecular sieve.

[0014] As an optimization, the weighing amounts of the components in step (5) are, by mass, 30-40 parts of polyether polyol, 10-20 parts of functionalized polysiloxane, 10-20 parts of 2,2-dihydroxymethylbutyric acid, 2-3 parts of pure water, 0.2-0.3 parts of dibutyltin dilaurate, 0.2-0.3 parts of triethylenediamine, 10-20 parts of antibacterial macroporous molecular sieve, 50-60 parts of diphenylmethane diisocyanate, and 10-12 parts of phosphorus-containing monomer.

[0015] As an optimization, the polyether polyol model in step (5) is 450L, purchased from Hengfeng Polyurethane Industrial Co., Ltd.

[0016] The present invention also provides an organosilicon foam prepared according to the preparation method of the organosilicon foam.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0018] When preparing the organosilicon foam, the present invention comprises the following steps: reacting octamethylcyclotetrasiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane and trifluoropropylmethylcyclotrisiloxane to obtain functionalized polysiloxane; reacting diallyl chlorophosphite and 4-aminomethyl-2,2,6,6-tetramethylpiperidine to obtain a phosphorus-containing monomer; reacting tetraethyl orthosilicate and sodium aluminate to obtain a microporous molecular sieve, then treating the microporous molecular sieve with an acid to obtain a macroporous molecular sieve, then grafting the microporous molecular sieve with a silane coupling agent and reacting the microporous molecular sieve with tetramethylguanidine to obtain an antibacterial macroporous molecular sieve; and finally using pure water as a foaming agent, foaming diphenylmethane diisocyanate, functionalized polysiloxane, a phosphorus-containing monomer, 2,2-dihydroxymethylbutyric acid and an antibacterial macroporous molecular sieve in one step to obtain the organosilicon foam.

[0019] First, octamethylcyclotetrasiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane and trifluoropropylmethylcyclotrisiloxane are reacted to obtain functionalized polysiloxane; 1,3,5,7-tetramethylcyclotetrasiloxane is subjected to ring-opening polymerization to introduce hydroxyl groups at both ends of the siloxane and fluorine elements on the side chains. The hydroxyl groups at both ends of the functionalized polysiloxane can be foamed with diphenylmethane diisocyanate and polyether polyol in one step to obtain silicone foam, and fluorine-containing siloxane is introduced into the foam. The siloxy groups on the main chain of the siloxane can promote the carbonization of the silicone foam at high temperature to form a silicate protective layer. The silicon element can also absorb active free radicals, terminate the chain reaction, and give the silicone foam excellent flame retardant properties. The fluorine element on the side chain has extremely strong electronegativity, which can enhance the strength and flame retardant properties of the silicone foam.

[0020] Secondly, diallyl chlorophosphite and 4-aminomethyl-2,2,6,6-tetramethylpiperidine are reacted to obtain a phosphorus-containing monomer; the prepared phosphorus-containing monomer contains not only flame-retardant phosphorus elements but also hindered amine structures; the phosphorus-containing monomer contains two double bonds, which can undergo a silylation reaction with hydroxyl-terminated hydrogen-containing siloxane in the subsequent foam formation process to form a cross-linked structure and introduce phosphorus elements and hindered amine structures into the foam. The phosphorus element has good flame retardant properties, and the hindered amine structure can terminate free radical chain reactions, giving the silicone foam excellent anti-aging properties;

[0021] Then, ethyl orthosilicate and sodium aluminate are reacted to obtain a microporous molecular sieve, which is then treated with an acid to obtain a macroporous molecular sieve, which is then modified with a silane coupling agent to obtain a modified macroporous molecular sieve, which is then reacted with tetramethylguanidine to obtain an antibacterial macroporous molecular sieve. The molecular sieve, as an inorganic filler, can be added to the foam to improve the hardness of the foam; the acid treatment can increase the pores of the molecular sieve, and this pore structure can improve the shock-absorbing and noise-reducing capabilities of the silicone foam; the silane coupling agent grafted on the molecular sieve reacts with tetramethylguanidine to obtain a molecular sieve with a quaternary ammonium salt structure, which provides antibacterial properties for the silicone foam;

[0022] Finally, diphenylmethane diisocyanate, functionalized polysiloxane, phosphorus-containing monomer, 2,2-dihydroxymethylbutyric acid and antibacterial macroporous molecular sieve are used for one-step foaming to obtain silicone foam. Diphenylmethane diisocyanate, functionalized polysiloxane and 2,2-dihydroxymethylbutyric acid are copolymerized, and the phosphorus-containing monomer undergoes hydrosilylation with the functionalized polysiloxane through double bonds. The antibacterial macroporous molecular sieve, as a quaternary ammonium salt-type positively charged inorganic filler, can electrostatically adsorb 2,2-dihydroxymethylbutyric acid to increase the dispersion of the molecular sieve in the polymer. At the same time, due to its porous structure and high specific surface area, the molecular sieve exhibits a strong adsorption capacity, which can adsorb the gas and heat generated during the combustion process, reduce the flammability of the material, and help the flame retardant to be evenly dispersed in the polymer matrix, thereby forming a seamless carbon layer during the combustion process. It can be used as a flame retardant synergist and can work together with phosphorus silicon to further enhance the flame retardancy of the silicone foam. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0024] The polyether polyol used in all the following examples and comparative examples is 450L, purchased from Hengfeng Polyurethane Industrial Co., Ltd.

[0025] Embodiment 1:

[0026] (1) Octamethylcyclotetrasiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane and trifluoropropyltrimethylcyclotrisiloxane were mixed uniformly in a mass ratio of 1:0.8:2.0, heated to 90°C under nitrogen protection, stirred for 40 min at a stirring speed of 500 r / min, and then heated to 120°C, 0.02% of the mass of octamethylcyclotetrasiloxane in a 25wt% tetramethylammonium hydroxide aqueous solution was added, and then 0.3% of the mass of octamethylcyclotetrasiloxane in pure water was added, and the mixture was stirred for 4 h. The mixture was heated to 150°C, reacted for 4 h, and the pressure was reduced to 2.5 KPa, and the reaction was continued for 4 h to obtain a functionalized polysiloxane;

[0027] (2) Diallyl chlorophosphite, 4-aminomethyl-2,2,6,6-tetramethylpiperidine and dichloromethane were mixed uniformly in a mass ratio of 1:1:50, and triethylamine (0.3 times the mass of diallyl chlorophosphite) was added under nitrogen protection, and the mixture was reacted at room temperature for 24 hours. The mixture was filtered and washed with dichloromethane for 4 times, and then washed with saturated sodium bicarbonate for 4 times. The mixture was dried under vacuum at room temperature for 24 hours, and the vacuum degree was 0.08 MPa to obtain a phosphorus-containing monomer.

[0028] (3) Weigh 1 part of aluminum isopropoxide, 10 parts of tetrapropylammonium hydroxide, 50 parts of tetraethyl orthosilicate, and 40 parts of urea in molar proportions, mix aluminum isopropoxide and 1 mol / L sodium hydroxide aqueous solution at a mass volume ratio of 1:1000 and stir for 1 h at a stirring speed of 300 r / min, then add tetrapropylammonium hydroxide and continue stirring for 2 h, slowly add tetraethyl orthosilicate dropwise at a dropping rate of 2 mL / min, continue stirring for 2 h after the addition is completed, add urea and continue stirring for 12 h, transfer the reaction system to a polytetrafluoroethylene reactor, react at 180°C for 24 h, filter and wash with pure water 8 times, and dry in a vacuum drying oven for 8 h to obtain a microporous molecular sieve;

[0029] (4) The microporous molecular sieve and 1 mol / L hydrochloric acid aqueous solution were mixed uniformly at a mass volume ratio of 1:20, heated to 70°C, and stirred for 2 h at a stirring speed of 600 r / min. The mixture was filtered and washed with pure water for 8 times, and dried in a vacuum drying oven at a vacuum degree of 0.08 MPa for 8 h to obtain a macroporous molecular sieve;

[0030] (5) The macroporous molecular sieve, 3-chloropropyltrimethoxysilane and anhydrous ethanol were mixed uniformly in a mass ratio of 1:1.5:50, stirred at 300 r / min for 24 h, then ultrasonicated at 40 kHz for 30 min, filtered and washed with ethanol 4 times, then washed with pure water 4 times, redispersed in xylene with an equal volume to anhydrous ethanol, added with tetramethylguanidine (0.6 times the mass of 3-chloropropyltrimethoxysilane), heated to 120°C, stirred for 4 h at a stirring speed of 400 r / min, cooled to room temperature, filtered and washed with pure water 4 times, and dried at 60°C for 8 h to obtain an antibacterial macroporous molecular sieve;

[0031] (6) Weigh 30 parts of polyether polyol, 10 parts of functionalized polysiloxane, 10 parts of 2,2-dihydroxymethylbutyric acid, 2 parts of pure water, 0.2 parts of dibutyltin dilaurate, 0.2 parts of triethylenediamine, 10 parts of antibacterial macroporous molecular sieve, 50 parts of 4,4'-diphenylmethane diisocyanate, and 10 parts of phosphorus-containing monomer, and stir the polyether polyol, functionalized polysiloxane, 2,2-dihydroxymethylbutyric acid, pure water, dibutyltin dilaurate, triethylenediamine and antibacterial macroporous molecular sieve at a stirring speed of 600 r / min for 30 min. Then, add 4,4'-diphenylmethane diisocyanate and phosphorus-containing monomer at 3000 rpm / min and stir for 20 seconds. Then, pour the mixture into a mold preheated to 90°C, cure at 80°C for 4 hours, and then heat to 120°C for 3 hours to obtain silicone foam.

[0032] Embodiment 2:

[0033] (1) Octamethylcyclotetrasiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane and trifluoropropyltrimethylcyclotrisiloxane were mixed uniformly in a mass ratio of 1:0.9:2.3, heated to 85°C under nitrogen protection, stirred for 35 min at a stirring speed of 450 r / min, and then heated to 115°C, 0.022% of the mass of octamethylcyclotetrasiloxane in a 25wt% aqueous solution of tetramethylammonium hydroxide was added, and then 0.35% of the mass of octamethylcyclotetrasiloxane in pure water was added, and the mixture was stirred for 3.5 h. The mixture was heated to 150°C, reacted for 3.5 h, and the pressure was reduced to 2 KPa, and the reaction was continued for 3.5 h to obtain a functionalized polysiloxane;

[0034] (2) Diallyl chlorophosphite, 4-aminomethyl-2,2,6,6-tetramethylpiperidine and dichloromethane were mixed uniformly in a mass ratio of 1:1.1:55, and triethylamine (0.35 times the mass of diallyl chlorophosphite) was added under nitrogen protection, and the mixture was reacted at room temperature for 23 hours. The mixture was filtered and washed with dichloromethane for 3 times, and then washed with saturated sodium bicarbonate for 3 times. The mixture was dried under vacuum at room temperature for 23 hours, and the vacuum degree was 0.08 MPa to obtain a phosphorus-containing monomer.

[0035] (3) Weigh 1 part of aluminum isopropoxide, 11 parts of tetrapropylammonium hydroxide, 52 parts of tetraethyl orthosilicate, and 41 parts of urea in molar proportions, mix aluminum isopropoxide and 1 mol / L sodium hydroxide aqueous solution at a mass volume ratio of 1:1200, and stir for 1.5 h at a stirring speed of 250 r / min, then add tetrapropylammonium hydroxide and continue stirring for 1.5 h, slowly add tetraethyl orthosilicate dropwise at a dropping rate of 2 mL / min, continue stirring for 1.5 h after the addition is completed, add urea and continue stirring for 11.5 h, transfer the reaction system to a polytetrafluoroethylene reactor, react at 180°C for 23 h, filter and wash with pure water 7 times, and dry in a vacuum drying oven for 7 h to obtain a microporous molecular sieve;

[0036] (4) The microporous molecular sieve and 1 mol / L hydrochloric acid aqueous solution were mixed uniformly at a mass volume ratio of 1:25, heated to 65°C, and stirred for 1.5 h at a stirring speed of 550 r / min. The mixture was filtered and washed with pure water for 7 times, and dried in a vacuum drying oven at a vacuum degree of 0.08 MPa for 7 h to obtain a macroporous molecular sieve;

[0037] (5) The macroporous molecular sieve, 3-chloropropyltrimethoxysilane and anhydrous ethanol were mixed uniformly in a mass ratio of 1:1.7:55, stirred at 230 r / min for 23 h, then ultrasonicated at 30 kHz for 25 min, filtered and washed with ethanol 3 times, then washed with pure water 3 times, redispersed in xylene with an equal volume of anhydrous ethanol, added with tetramethylguanidine (0.7 times the mass of 3-chloropropyltrimethoxysilane), heated to 110 ° C, stirred for 3.5 h, stirring speed 350 r / min, cooled to room temperature, filtered and washed with pure water 3 times, and dried at 55 ° C for 7 h to obtain an antibacterial macroporous molecular sieve;

[0038] (6) Weigh 35 parts of polyether polyol, 15 parts of functionalized polysiloxane, 15 parts of 2,2-dimethylolbutyric acid, 3 parts of pure water, 0.2 parts of dibutyltin dilaurate, 0.3 parts of triethylenediamine, 15 parts of antibacterial macroporous molecular sieve, 55 parts of 4,4'-diphenylmethane diisocyanate, and 11 parts of phosphorus-containing monomer, and mix the polyether polyol, functionalized polysiloxane, 2,2-dimethylolbutyric acid, pure water, dibutyltin dilaurate, and 0.2 parts of dibutyltin dilaurate. Dibutyltin laurate, triethylenediamine and antibacterial macroporous molecular sieve were stirred at a stirring speed of 550 r / min for 25 min, 4,4'-diphenylmethane diisocyanate and phosphorus-containing monomer were added at 3000 rpm / min and stirred for 15 s. The mixture was poured into a mold preheated to 85°C, cured at 80°C for 3.5 h, and then cured in an oven heated to 115°C for 2.5 h to obtain silicone foam.

[0039] Embodiment 3:

[0040] (1) Octamethylcyclotetrasiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane and trifluoropropyltrimethylcyclotrisiloxane were mixed uniformly in a mass ratio of 1:1:2.5, heated to 80°C under nitrogen protection, stirred for 30 min at a stirring speed of 400 r / min, and then heated to 110°C, 0.03% of the mass of octamethylcyclotetrasiloxane in a 25wt% tetramethylammonium hydroxide aqueous solution was added, and then 0.4% of the mass of octamethylcyclotetrasiloxane in pure water was added and stirred for 3 h, heated to 150°C, reacted for 3 h, reduced pressure to 2 KPa, and continued to react for 3 h to obtain functionalized polysiloxane;

[0041] (2) Diallyl chlorophosphite, 4-aminomethyl-2,2,6,6-tetramethylpiperidine and dichloromethane were mixed uniformly in a mass ratio of 1:1:60, and triethylamine (0.4 times the mass of diallyl chlorophosphite) was added under nitrogen protection, and the mixture was reacted at room temperature for 22 hours. The mixture was filtered and washed with dichloromethane for 3 times, and then washed with saturated sodium bicarbonate for 3 times. The mixture was dried under vacuum at room temperature for 22 hours, and the vacuum degree was 0.08 MPa to obtain a phosphorus-containing monomer.

[0042] (3) Weigh 2 parts of aluminum isopropoxide, 12 parts of tetrapropylammonium hydroxide, 55 parts of tetraethyl orthosilicate, and 42 parts of urea in molar proportions, mix aluminum isopropoxide and 1 mol / L sodium hydroxide aqueous solution at a mass volume ratio of 1:1500 and stir for 1 hour at a stirring speed of 200 r / min, then add tetrapropylammonium hydroxide and continue stirring for 1 hour, slowly add tetraethyl orthosilicate dropwise at a dropping rate of 2 mL / min, continue stirring for 1 hour after the addition is completed, add urea and continue stirring for 11 hours, transfer the reaction system to a polytetrafluoroethylene reactor, react at 180°C for 22 hours, filter and wash with pure water 6 times, and dry in a vacuum drying oven for 6 hours to obtain a microporous molecular sieve;

[0043] (4) The microporous molecular sieve and 1 mol / L hydrochloric acid aqueous solution were mixed uniformly at a mass volume ratio of 1:20, heated to 60°C, and stirred for 1 h at a stirring speed of 500 r / min. The mixture was filtered and washed with pure water for 6 times, and dried in a vacuum drying oven at a vacuum degree of 0.08 MPa for 6 h to obtain a macroporous molecular sieve;

[0044] (5) The macroporous molecular sieve, 3-chloropropyltrimethoxysilane and anhydrous ethanol were mixed uniformly in a mass ratio of 1:2:60, stirred at 200 r / min for 22 h, then ultrasonicated at 20 kHz for 20 min, filtered and washed with ethanol three times, then washed with pure water three times, redispersed in xylene with an equal volume to anhydrous ethanol, added with tetramethylguanidine (0.8 times the mass of 3-chloropropyltrimethoxysilane), heated to 100 ° C, stirred for 3 h at a stirring speed of 300 r / min, cooled to room temperature, filtered and washed with pure water three times, and dried at 50 ° C for 6 h to obtain an antibacterial macroporous molecular sieve;

[0045] (6) Weigh 40 parts of polyether polyol, 20 parts of functionalized polysiloxane, 20 parts of 2,2-dihydroxymethylbutyric acid, 3 parts of pure water, 0.3 parts of dibutyltin dilaurate, 0.3 parts of triethylenediamine, 20 parts of antibacterial macroporous molecular sieve, 60 parts of 4,4'-diphenylmethane diisocyanate and antibacterial macroporous molecular sieve at a stirring speed of 500 r / min for 20 min, add 4,4'-diphenylmethane diisocyanate and phosphorus-containing monomer at 3000 rpm / min, stir for 10 s, pour into a mold preheated to 80°C, cure at 80°C for 3 h, and then heat to 110°C for 2 h to obtain silicone foam.

[0046] Comparative Example 1

[0047] The preparation method of the silicone foam of Comparative Example 1 is different from that of Example 2 in that step (2) is omitted and step (6) is replaced by weighing 35 parts of polyether polyol, 15 parts of functionalized polysiloxane, 15 parts of 2,2-dihydroxymethylbutyric acid, 3 parts of pure water, 0.2 parts of dibutyltin dilaurate, 0.3 parts of triethylenediamine, 15 parts of antibacterial macroporous molecular sieve, and 55 parts of 4,4'-diphenylmethane diisocyanate, by weight, and mixing the polyether polyol, the functionalized polysiloxane, and the 2,2-dihydroxymethylbutyric acid. Siloxane, 2,2-dihydroxymethylbutyric acid, pure water, dibutyltin dilaurate, triethylenediamine and antibacterial macroporous molecular sieve were stirred at a stirring speed of 550 r / min for 25 min, 4,4'-diphenylmethane diisocyanate was added at 3000 rpm / min and stirred for 15 s, and then poured into a mold preheated to 85°C, cured at 80°C for 3.5 h, and placed in an oven at 125°C for 2.5 h to obtain silicone foam.

[0048] Comparative Example 2

[0049] The preparation method of the silicone foam of Comparative Example 2 is different from that of Example 2 in that steps (3), (4) and (5) are omitted, and step (6) is modified to weigh 35 parts of polyether polyol, 15 parts of functionalized polysiloxane, 15 parts of 2,2-dihydroxymethylbutyric acid, 3 parts of pure water, 0.2 parts of dibutyltin dilaurate, 0.3 parts of triethylenediamine, 55 parts of 4,4'-diphenylmethane diisocyanate, and 11 parts of phosphorus-containing monomer, and add polyether polyol to the mixture. , functionalized polysiloxane, 2,2-dihydroxymethylbutyric acid, pure water, dibutyltin dilaurate and triethylenediamine, stirred at a stirring speed of 550r / min for 25min, added 4,4'-diphenylmethane diisocyanate and phosphorus-containing monomer at 3000rpm / min, stirred for 15s, poured into a mold preheated to 85°C, cured at 80°C for 3.5h, and placed in an oven at 125°C for 2.5h to obtain silicone foam.

[0050] Comparative Example 3

[0051] The difference between the preparation method of the silicone foam of Comparative Example 3 and Example 2 is that step (5) is modified to uniformly mix the macroporous molecular sieve, 3-chloropropyltrimethoxysilane and anhydrous ethanol in a mass ratio of 1:1.7:55, stir at 230 r / min for 23 hours, then ultrasonicate at 30 kHz for 25 minutes, filter and wash with ethanol 3 times, then wash with pure water 3 times, and dry at 55°C for 7 hours to obtain the antibacterial macroporous molecular sieve.

[0052] Comparative Example 4

[0053] The preparation method of the silicone foam of Comparative Example 4 is different from that of Example 2 in that step (1) is modified to uniformly mix octamethylcyclotetrasiloxane and 1,3,5,7-tetramethylcyclotetrasiloxane in a mass ratio of 1:0.9, heat to 85°C under nitrogen protection, stir for 35 min at a stirring speed of 450 r / min, continue to heat to 115°C, add 25wt% tetramethylammonium hydroxide aqueous solution with a mass ratio of 0.022% of octamethylcyclotetrasiloxane, then add pure water with a mass ratio of 0.35% of octamethylcyclotetrasiloxane, continue to stir for 3.5 h, heat to 150°C, react for 3.5 h, reduce the pressure to 2 KPa, and continue to react for 3.5 h to obtain functionalized polysiloxane;

[0054] Test Example 1

[0055] Flame retardant performance test

[0056] Test method:

[0057] The limiting oxygen index of the examples and comparative examples was tested according to GB / T 2406-93 standard. The results are shown in Table 1.

[0058] Table 1

[0059]

[0060] From the comparison of the experimental data of Examples 1-3 and Comparative Examples 1-4 in Table 1, it can be found that the organic silicone foam prepared in the present invention has good flame retardant properties.

[0061] By comparison, the limiting oxygen index of Examples 1-3 is greater than that of Comparative Examples 1, 2 and 4, indicating that octamethylcyclotetrasiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane and trifluoropropylmethylcyclotrisiloxane are reacted to prepare functionalized polysiloxane; 1,3,5,7-tetramethylcyclotetrasiloxane is subjected to ring-opening polymerization to introduce fluorine element on the side chain, thereby introducing fluorine-containing siloxane on the foam. The siloxy groups on the main chain of siloxane can promote the carbonization of silicone foam at high temperature to form a silicate protective layer. The silicon element can also absorb active free radicals, terminate the chain reaction, and give the silicone foam excellent flame retardant properties. The fluorine element on the side chain has a very strong electronegativity, which can enhance the flame retardant properties of the silicone foam; diallyl chlorophosphite and 4-aminomethyl-2, 2,6,6-tetramethylpiperidine is reacted to obtain a phosphorus-containing monomer; the prepared phosphorus-containing monomer contains phosphorus, which can be introduced into the foam with flame retardant properties; tetraethyl orthosilicate and sodium aluminate are reacted to obtain a microporous molecular sieve, which is then treated with acid to obtain a macroporous molecular sieve, which is then modified with a silane coupling agent to obtain a modified macroporous molecular sieve, which is then reacted with tetramethylguanidine to obtain an antibacterial macroporous molecular sieve. The molecular sieve exhibits a strong adsorption capacity due to its porous structure and high specific surface area, and can adsorb gases and heat generated during combustion, reduce the flammability of the material, and help the flame retardant to be evenly dispersed in the polymer matrix, thereby forming a seamless carbon layer during the combustion process. It can be used as a flame retardant synergist and can work together with phosphorus silicon to further enhance the flame retardant properties of silicone foam.

[0062] Test Example 2

[0063] Compression strength and anti-aging performance testing

[0064] Test method:

[0065] Compression strength test: The prepared silicone foam was cut into 30mm×30mm×30mm standard specimens by a cutting machine, and placed under a universal tensile testing machine. The compression test mode of the tensile testing machine was selected to compress the standard specimen by 66.6% according to the height, and the compression strength of the specimen was tested. The compression speed of the testing machine was 10mm / min.

[0066] Anti-aging performance test: Place a 30mm×30mm×30mm standard sample in an aging box, and age it at 120℃ and 32% oxygen concentration for 72 hours. Take it out after aging, and measure its compression strength after aging according to the compression test standard, and calculate the change rate of compression strength before and after aging. The results are shown in Table 2.

[0067] Table 2

[0068]

[0069] From the comparison of the experimental data of Examples 1-3 and Comparative Examples 1-4 in Table 2, it can be found that the organic silicone foam prepared in the present invention has high strength and good anti-aging performance.

[0070] By comparison, the compressive strength of Examples 1-3 is greater than that of Comparative Examples 2 and 4, indicating that octamethylcyclotetrasiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane and trifluoropropylmethylcyclotrisiloxane are reacted to prepare functionalized polysiloxane; 1,3,5,7-tetramethylcyclotetrasiloxane is subjected to ring-opening polymerization to introduce fluorine element on the side chain, and the fluorine element on the side chain has a very strong electronegativity, which can enhance the strength of the silicone foam; diallyl chlorophosphite and 4-aminomethyl-2,2,6,6-tetramethylpiperidine are reacted to prepare Phosphorus-containing monomer; the prepared phosphorus-containing monomer contains a hindered amine structure, thereby introducing the hindered amine structure into the foam, and the hindered amine structure can terminate the free radical chain reaction, giving the silicone foam excellent anti-aging properties; tetraethyl orthosilicate and sodium aluminate are reacted to obtain a microporous molecular sieve, which is then treated with an acid to obtain a macroporous molecular sieve, which is then modified with a silane coupling agent to obtain a modified macroporous molecular sieve, and then reacted with tetramethylguanidine to obtain an antibacterial macroporous molecular sieve. The molecular sieve, as an inorganic filler, can be added to the foam to greatly improve the hardness of the foam.

[0071] Test Example 3

[0072] Antimicrobial performance testing

[0073] Test method:

[0074] The antibacterial properties of the examples and comparative examples were tested using an oscillation method according to GB / T 20944-2008, and the bacterial species used in the test were Gram-negative bacteria Escherichia coli and Gram-positive bacteria Staphylococcus aureus. The results are shown in Table 3.

[0075] Table 3

[0076]

[0077] From the comparison of the experimental data of Examples 1-3 and Comparative Examples 1-4 in Table 3, it can be found that the organic silicone foam prepared by the present invention has good antibacterial properties.

[0078] By comparison, the antibacterial properties of Examples 1-3 are greater than those of Comparative Examples 2 and 4, indicating that a microporous molecular sieve is prepared by reacting tetraethyl orthosilicate and sodium aluminate, which is then treated with an acid to obtain a macroporous molecular sieve, which is then modified with a silane coupling agent to obtain a modified macroporous molecular sieve, which is then reacted with tetramethylguanidine to obtain an antibacterial macroporous molecular sieve, and the silane coupling agent grafted on the molecular sieve reacts with tetramethylguanidine to obtain a molecular sieve with a quaternary ammonium salt structure, which provides antibacterial properties for the silicone foam.

[0079] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and scope of the equivalent elements of the claims be included in the invention. Any marking in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for preparing silicone foam, characterized in that: The method comprises the following preparation steps: (1) Octamethylcyclotetrasiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane and trifluoropropyltrimethylcyclotrisiloxane are mixed uniformly in a mass ratio of 1:0.8-1:2.0-2.5, heated to 80-90°C under nitrogen protection, stirred for 30-40 min at a stirring speed of 400-500 r / min, and then heated to 110-120°C, 0.02-0.03% of the mass of octamethylcyclotetrasiloxane in a 25wt% tetramethylammonium hydroxide aqueous solution is added, and then 0.3-0.4% of the mass of octamethylcyclotetrasiloxane in pure water is added, and the mixture is stirred for 3-4h, heated to 150°C, reacted for 3-4h, and decompressed to 2-2.5Kpa, and reacted for 3-4h to obtain a functionalized polysiloxane; (2) Diallyl chlorophosphite, 4-aminomethyl-2,2,6,6-tetramethylpiperidine and dichloromethane are mixed uniformly in a mass ratio of 1:1-1.2:50-60, and triethylamine in an amount of 0.3-0.4 times the mass of diallyl chlorophosphite is added under nitrogen protection, reacting at room temperature for 22-24 hours, filtering and washing with dichloromethane for 3-4 times, and then washing with saturated sodium bicarbonate for 3-4 times, and drying under vacuum at room temperature for 22-24 hours with a vacuum degree of 0.08 MPa to obtain a phosphorus-containing monomer; (3) Aluminum isopropoxide and 1 mol / L sodium hydroxide aqueous solution were mixed and stirred at a mass volume ratio of 1:1000-1500 for 1-2 hours at a stirring speed of 200-300 r / min, and then tetrapropylammonium hydroxide was added and stirred for 1-2 hours, and ethyl orthosilicate was slowly added dropwise at a rate of 2 mL / min. After the addition was completed, stirring was continued for 1-2 hours, and urea was added and stirred for 11-12 hours. The reaction system was transferred to a polytetrafluoroethylene reactor, reacted at 180°C for 22-24 hours, filtered, washed with pure water for 6-8 times, and dried in a vacuum drying oven for 6-8 hours to obtain a microporous molecular sieve; (4) The macroporous molecular sieve obtained after the acid treatment of the microporous molecular sieve, 3-chloropropyltrimethoxysilane and anhydrous ethanol are mixed uniformly in a mass ratio of 1:1.5-2:50-60, stirred at 200-300 r / min for 22-24 hours, then ultrasonicated at 20-40 kHz for 20-30 minutes, filtered and washed with ethanol 3-4 times, then washed with pure water 3-4 times, redispersed in xylene with an equal volume of anhydrous ethanol, added with tetramethylguanidine with a mass of 0.6-0.8 times of 3-chloropropyltrimethoxysilane, heated to 100-120°C, stirred for 3-4 hours at a stirring speed of 300-400 r / min, cooled to room temperature, filtered and washed with pure water 3-4 times, and dried at 50-60°C for 6-8 hours to obtain an antibacterial macroporous molecular sieve; (5) Weigh polyether polyol, functionalized polysiloxane, 2,2-dihydroxymethylbutyric acid, pure water, dibutyltin dilaurate, triethylenediamine and antibacterial macroporous molecular sieve, stir at a stirring speed of 500-600 r / min for 20-30 min, add diphenylmethane diisocyanate and phosphorus-containing monomer at 3000 rpm / min, stir for 10-20 s, pour into a mold preheated to 80-90°C, cure at 80°C for 3-4 h, and then heat to 110-120°C for 2-3 h to obtain silicone foam.

2. The method for preparing a silicone foam according to claim 1, characterized in that: The weighed amounts of the reagents in step (3) are, by mole, 1-2 parts of aluminum isopropoxide, 10-12 parts of tetrapropylammonium hydroxide, 50-55 parts of tetraethyl orthosilicate, and 40-42 parts of urea.

3. The method for preparing a silicone foam according to claim 1, characterized in that: The specific steps of obtaining the macroporous molecular sieve by acid treatment of the microporous molecular sieve in step (4) are as follows: uniformly mixing the microporous molecular sieve and 1 mol / L hydrochloric acid aqueous solution at a mass volume ratio of 1:20-30, heating to 60-70° C., continuing to stir the reaction for 1-2 h at a stirring speed of 500-600 r / min, filtering and washing with pure water for 6-8 times, and drying in a vacuum drying oven at a vacuum degree of 0.08 MPa for 6-8 h to obtain the macroporous molecular sieve.

4. The method for preparing a silicone foam according to claim 1, characterized in that: The weighed amounts of the components in step (5) are, by mass, 30-40 parts of polyether polyol, 10-20 parts of functionalized polysiloxane, 10-20 parts of 2,2-dihydroxymethylbutyric acid, 2-3 parts of pure water, 0.2-0.3 parts of dibutyltin dilaurate, 0.2-0.3 parts of triethylenediamine, 10-20 parts of antibacterial macroporous molecular sieve, 50-60 parts of diphenylmethane diisocyanate, and 10-12 parts of phosphorus-containing monomer.

5. The method for preparing a silicone foam according to claim 1, characterized in that: The polyether polyol model in step (5) is 450L.

6. An organosilicon foam prepared according to the method for preparing organosilicon foam according to claim 1.

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