Photoinitiated foamed material and method for its production

Abstract

The application discloses a kind of photo-initiated foaming material and preparation method thereof, the raw material of the material includes polymer prepolymer, photo-initiated foaming agent and photo-initiator, wherein the photo-initiated foaming agent epoxy hyperbranched organosilicon polymer, structural formula is (I);Its preparation method is as follows: (1) raw materials are mixed, and cast to mold;(2) foaming, curing is obtained under the irradiation of ultraviolet lamp, and the foaming material;The foaming material is introduced into the photo-initiated foaming agent epoxy hyperbranched organosilicon polymer, and can realize rapid foaming, curing under the condition of ultraviolet light, and the foaming material is obtained;The preparation time of thermosetting epoxy resin foam and the required energy consumption are greatly shortened, the demand for large equipment of thermosetting epoxy resin foam material production is reduced, the construction site rapid foaming is realized, and has wide application prospect in aerospace, military national defense, automobile industry, biology, electronics, medicine field.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of foamed materials and its preparation method, especially a kind of photo-initiated foamed material and its preparation method. BACKGROUND

[0002] A kind of lightweight high molecular material formed by a large number of gas micro-holes uniformly dispersed in solid plastic is called foam plastic or porous plastic. Traditionally, foam materials are generally prepared by free foaming or molding foaming method. According to the different foaming agents, there are mainly three methods to prepare foam materials, namely chemical foaming method, physical foaming method and hollow microsphere filling method.

[0003] Hollow microsphere filling method, that is, adding hollow microspheres in resin material system, and then curing to form lightweight composite material. Chinese patent CN103965585A prepares hollow glass bead modified resin composite material by adding organic montmorillonite and temperature segmentation pouring curing method. This method can effectively solve the problem of phase separation of composite material, and realize the uniform dispersion of hollow glass beads in matrix. But due to the limitation of the density and the amount of hollow microspheres, this method is often used to prepare high-density resin-based foam materials, and cannot be used to prepare low-density lightweight foam materials.

[0004] Physical foaming method is to use low-boiling point liquid as foaming agent, and use the heat released by resin curing reaction to evaporate low-boiling point liquid to foam, and then pouring or spraying to prepare foam plastic products or foam plastic coating. Chinese patent CN114316340A uses azo foaming agent to blend with resin material and filler, and uses pouring molding method to prepare semi-rigid resin-based foam material. But the foam material obtained by this method has poor cell uniformity and poor thermal stability, and the application of low-boiling point foaming agent has been limited due to environmental considerations.

[0005] Chemical foaming method is to use the heat of resin curing to decompose chemical foaming agent to produce gas, which is dispersed in resin to foam, and then pouring to prepare foam plastic products. Chinese patent CN110499017A introduces isocyanate group into resin system, and uses the reaction of isocyanate and water to generate carbon dioxide gas to prepare resin foam material. But the introduction of isocyanate reduces the thermal stability of resin material, and the foaming method has long construction period, high energy consumption and inconvenient construction. From the perspective of convenience and environmental protection, it has obvious defects.

[0006] In summary, the current resin-based foam preparation methods all have the problems of serious environmental pollution, single application scene, long processing period and high energy consumption of equipment. Therefore, a resin-based foam material preparation method with universality, rapid forming, convenient operation and low dependence on processing equipment has become the top priority of foam material development.

[0007] UV curing technology is a new technology in the field of polymer preparation. Under the irradiation of UV light, the photo initiator in liquid material is excited, and the polymerization reaction of the compound with unsaturated bond in the material is initiated, and the polymer network structure is crosslinked. Its outstanding features are energy saving, high efficiency, fast polymerization rate and high yield. In the production process, no heating is required, energy consumption is low, investment is small, and no post-treatment process is required. Under the influence of the green economy advocated in various countries in the world, the development prospect is very promising. If the photo-curing technology is introduced into the preparation of resin-based foam materials, the problems currently faced by the traditional foam material preparation industry can be greatly solved.

[0008] However, due to the high difficulty of the research and development of photo-curing foaming process, the patent of the foam material preparation technology using photo-curing process is still in a blank state. If a breakthrough is made in this field, it will be a great innovation for the resin-based foam material processing industry. SUMMARY

[0009] The first object of the present application is to provide a photo-initiated foaming material which is foamed and cured under the condition of UV light irradiation. The second object of the present application is to provide a preparation method of the photo-initiated foaming material.

[0010] Technical scheme: The photo-initiated foaming material provided by the present application comprises a polymer prepolymer, a photo-initiated foaming agent and a photo initiator, wherein the photo-initiated foaming agent is an epoxy-based hyperbranched organosilicon polymer, and the structural formula thereof is as follows:

[0011]

[0012] wherein R is one or a combination of glycidyl ether epoxy and epoxy cyclohexane epoxy, and R' is one or a combination of phenyl, methyl, n-propyl, n-hexyl, isopropyl, isobutyl, cyclohexyl, n-octyl, n-dodecyl and n-hexadecyl.

[0013] The structural formula of the glycidyl ether epoxy is as follows:

[0014]

[0015] The structural formula of the epoxy cyclohexane epoxy is as follows:

[0016]

[0017] The epoxy-based hyperbranched organosilicon polymer plays a role of photo-initiated foaming agent on one hand, and foams under the irradiation of UV light after being initiated by the photo initiator; on the other hand, the hyperbranched epoxy resin can form a crosslinked network structure with the polymer prepolymer, and plays a role of improving the performance of the final material.

[0018] The preferred epoxy value of the epoxy-based hyperbranched organosilicon polymer is 0.01-2.

[0019] The role of the polymer prepolymer is to serve as a foam material matrix structure, giving the foam material certain strength and toughness. The polymer prepolymer is one or more of a class of polymers containing at least one epoxy group in the molecular chain. Preferably, the polymer prepolymer is an F-51 type epoxy resin, an E-44 type epoxy resin, an E-51 type epoxy resin, or a polyurethane modified epoxy resin.

[0020] The role of the photoinitiator is that under ultraviolet light irradiation, the cationic photoinitiator (photoacid generator) absorbs energy and undergoes photolysis, releasing acidic substances (super strong protonic acid), catalyzing the release of volatile small molecule gas from the siloxane condensation in the epoxy-based hyperbranched organosilicon monomer, playing a role in pore forming and foaming in the reaction system. At the same time, the cationic active center attacks the epoxy group to initiate ring-opening polymerization, causing the molecular weight of the reaction system to rapidly increase, thereby achieving the role of inducing monomer crosslinking and curing in a short time. The combination of the above two reaction mechanisms realizes the preparation of a photo-initiated foam material. Preferably, the photoinitiator is one or more of diazonium salt, diaryl iodonium salt, triaryl sulfonium salt, alkyl sulfonium salt, iron arene salt, sulfonyloxy ketone, and triaryl silyl ether.

[0021] Preferably, the prepolymer is selected from F-51 type epoxy resin, and the epoxy-based hyperbranched organosilicon polymer has an epoxy cyclohexane ring epoxy and a methyl group, and the structure is as follows:

[0022]

[0023] The epoxy-based hyperbranched organosilicon polymer is combined with the F-51 type epoxy resin to obtain a hard foam material with high compression resistance and temperature resistance under ultraviolet light induction. The F-51 type epoxy resin is purchased from SINOPEC Baling Petrochemical Co., Ltd.

[0024] Preferably, the prepolymer is selected from E-44 type epoxy resin, and the epoxy-based hyperbranched organosilicon polymer has a glycidyl ether group and a n-octyl group, and the structure is as follows:

[0025]

[0026] The epoxy-based hyperbranched organosilicon polymer is combined with the E-44 type epoxy resin to obtain a soft foam material with high resilience under ultraviolet light induction. The E-44 type epoxy resin is purchased from SINOPEC Baling Petrochemical Co., Ltd.

[0027] Preferably, the prepolymer is selected from E-51 type epoxy resin, and the epoxy-based hyperbranched organosilicon polymer has a glycidyl ether group and a phenyl group, and the structure is as follows:

[0028]

[0029] The epoxy-based hyperbranched organosilicon polymer is combined with the E-51 type epoxy resin to obtain a semi-rigid foamed material with slow rebound under the induction of ultraviolet light.

[0030] Preferably, the raw materials of the foamed material further include one or more of reinforcing fillers, nucleating agents, structure control agents, and flame retardants.

[0031] The reinforcing fillers improve the mechanical strength and flame retardant performance of the foamed material, and meanwhile, improve the dimensional stability of the product, reduce the shrinkage, and reduce the thermal deformation.

[0032] The nucleating agents induce the generation of cells, and meanwhile, make the pores more fine and uniform.

[0033] The structure control agents adjust the proportion of linear units and crosslinking units in the foamed material, and improve the flexibility of the foamed material.

[0034] Preferably, the raw materials of the foamed material include, by weight, 5-80 parts of polymer prepolymer, 15-40 parts of the light-initiated foaming agent epoxy-based hyperbranched organosilicon polymer, 3-5 parts of the light initiator, 0-40 parts of the structure control agent, 0-10 parts of the reinforcing filler, 0-10 parts of the nucleating agent, and 0-10 parts of the flame retardant.

[0035] The preparation method of the light-initiated foamed material includes the following steps:

[0036] (1) mixing the raw materials and pouring into a mold;

[0037] (2) foaming and curing under the irradiation of an ultraviolet lamp to obtain the foamed material.

[0038] In actual use, for the convenience of use and sales, the polymer prepolymer, the filler and the photoinitiator can be configured as the B component, and the photoinitiating foaming agent, the structure control agent and the nucleating agent can be configured as the A component for packaging. When the foam material is needed, the A and B components can be mixed uniformly, and then the foam material can be obtained through corresponding reaction conditions.

[0039] In the preparation of the foam material, the polymer prepolymer and the structure control agent are rapidly cured and formed under light irradiation, and a large amount of gas is generated from the photoinitiating foaming agent under the induction of the photoinitiator, which can generate a large number of microporous structures in the polymer and has a synergistic effect with the structure control agent.

[0040] As preferred, the light source of the photoinitiating foaming process is an ultraviolet lamp with a wavelength of 254 nm to 405 nm.

[0041] Invention mechanism: The present application provides a new idea for preparing a foam material: gas production and pore formation of a photoinitiating foaming agent. The polymer prepolymer is directly cured and formed under light irradiation, and the photoinitiating foaming agent, epoxy-based hyperbranched organosilicon polymer, is induced to generate gas under light irradiation, and the gas diffuses in the cured product to leave a pore structure, so that the cured product forms a low-density foam material with a porous structure.

[0042] The present application realizes rapid in-situ foaming at room temperature by introducing the photoinitiating foaming agent, and can successfully prepare an epoxy resin foam material with uniform texture, low density, high strength and high temperature resistance within tens of seconds or even seconds. At the same time, by adjusting the formula of the photoinitiating foaming precursor composition, epoxy resin foam materials with hard, semi-hard and soft properties can be prepared.

[0043] Advantages: Compared with the prior art, the present application has the following obvious advantages: (1) By introducing the photoinitiating foaming agent, epoxy-based hyperbranched organosilicon polymer, rapid foaming and curing can be realized under ultraviolet light irradiation to obtain a foaming material; (2) The method greatly shortens the preparation time and energy consumption of the thermosetting epoxy resin foam, reduces the demand for large equipment in the production of the thermosetting epoxy resin foam material, realizes rapid foaming on the construction site, and has a wide application prospect in the fields of aerospace, military and national defense, automobile industry, biology, electronics and medicine. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 The figures are schematic diagrams of the photoinitiating foaming precursor composition before and after foaming of Example 1, (a) is the diagram of the photoinitiating foaming precursor composition before foaming, and (b) is the diagram of the photoinitiating foaming precursor composition after foaming;

[0045] Figure 2 It is a compression performance test diagram of the hard silicone-modified epoxy foam prepared in Example 1.

[0046] Figure 3 Thermogravimetric analysis diagram of the hard silicone modified epoxy foam prepared in Example 1, (a) is a TG test diagram, (b) is a DTG test diagram;

[0047] Figure 4 Bending test diagram of the soft silicone modified epoxy foam prepared in Example 2, (a) is a foam bending test diagram, (b) is a diagram after the foam bending recovery;

[0048] Figure 5 Compression performance test diagram of the soft silicone modified epoxy foam prepared in Example 2;

[0049] Figure 6 Thermogravimetric analysis diagram of the soft silicone modified epoxy foam prepared in Example 2, (a) is a TG test diagram, (b) is a DTG test diagram;

[0050] Figure 7 Scanning electron microscope test diagram of the hard silicone modified epoxy foam prepared in Example 3 at different magnifications;

[0051] Figure 8 Compression performance test diagram of the semi-hard silicone modified epoxy foam prepared in Example 3;

[0052] Figure 9 Thermogravimetric analysis diagram of the semi-hard silicone modified epoxy foam prepared in Example 3, (a) is a TG test diagram, (b) is a DTG test diagram. DETAILED DESCRIPTION

[0053] The technical solutions of the present application will be further described below in combination with examples.

[0054] Example 1

[0055] The raw materials of the light-initiated foaming material of the present application include, by weight fraction: 55 parts of polymer prepolymer F-51 type epoxy resin, 15 parts of light-initiated foaming agent ester ring type epoxy-based hyperbranched silicone resin, 5 parts of light initiator diaryl iodonium salt, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylmethyl 7 parts of acid ester, 8 parts of trimethylolpropane glycidyl ether, 2 parts of nucleating agent silicon dioxide, 3 parts of weather white carbon black, and 5 parts of glass powder as filler; wherein the structure formula of the light-initiated foaming agent ester ring type epoxy-based hyperbranched silicone resin is as follows:

[0056]

[0057] The preparation method of the photoinitiating foaming agent ester ring epoxy hyperbranched organosilicon resin is as follows: 123g (0.5mol) of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 68g (0.5mol) of methyltrimethoxysilane, 150g of methanol are weighed and placed into a three-necked flask equipped with a condenser, a constant pressure dropping funnel and a thermometer. The mixture is stirred evenly, and then 5ml of 36.5wt% hydrochloric acid is added dropwise. After the addition is completed, the mixture is refluxed at 120℃ for 4h. After the reaction is completed, stirring is stopped, and byproducts are removed by rotary evaporation at 55℃ to obtain the ester ring epoxy hyperbranched organosilicon resin.

[0058] The preparation method of photo-initiated foaming material is as follows:

[0059] (1) Preparation of photo-initiated foaming material precursor composition: The raw materials are put into a round bottom flask and stirred and mixed in the dark for 30 minutes. After high-speed mixing, the photo-initiated foaming material precursor composition is obtained.

[0060] (2) Preparation of photo-initiated foaming material: The photo-initiated foaming material precursor composition was poured into a transparent mold and cured by UV irradiation. The sample was irradiated for 120 seconds under a 365nm UV lamp with a power of 100W. After the sample cooled, it was demolded and placed at room temperature for 30 minutes for post-curing. Finally, a high-compression-resistant and high-temperature-resistant rigid silicone-modified epoxy foaming material was obtained.

[0061] Figure 1 Images before and after light exposure show the photo-initiated foaming precursor composition, demonstrating a foaming ratio of 5.5 times. The density of this foaming material was measured to be 0.16 g / cm³. 3 Its hardness is 82 Shore A, and its compressive strength is 220 kPa. Figure 2 ), T 5％ =351.2℃, residual mass at 1000℃ 24% ( Figure 3 It has hardness, high compressive strength, and temperature resistance.

[0062] Example 2

[0063] The photoinitiated foaming material of the present invention comprises, by weight, the following raw materials: 20 parts of E-44 type epoxy resin prepolymer, 25 parts of photoinitiator hyperbranched silicone resin with terminal epoxy groups, 5 parts of photoinitiator diazonium tetrafluoroborate, 15 parts of structure control agents 1,6-hexanediol diglycidyl ether and 20 parts of 3-ethyl-3-hydroxymethyloxetane, 9 parts of silica gel particles and 1 part of carbon black as nucleating agents, and 5 parts of chopped glass fiber as filler; wherein, the structural formula of the photoinitiator hyperbranched silicone resin with ester ring epoxy groups is as follows:

[0064]

[0065] The preparation method of the light-initiated foaming agent terminal epoxy hyperbranched organosilicon resin is as follows: 118 g (0.5 mol) of 3-glycidyl ether propyl trimethoxysilane, 68 g (0.5 mol) of methyl trimethoxysilane and 150 g of tetrahydrofuran are weighed respectively, and then are mixed uniformly in a three-necked flask equipped with a condenser, a constant pressure dropping funnel and a thermometer, then 3 ml of 36.5 wt% hydrochloric acid is added dropwise, and after the dropwise addition is completed, the reaction is carried out at 70 DEG C for 24 h under reflux. After the reaction is completed, the stirring is stopped, and the by-product is removed by rotary evaporation at 55 DEG C to obtain the terminal epoxy hyperbranched organosilicon resin.

[0066] The preparation method of the light-initiated foaming material is as follows:

[0067] (1) Preparation of the light-initiated foaming material precursor composition: the raw materials are put into a round-bottom flask, and are mixed uniformly under stirring in the dark for 30 min, and then the light-initiated foaming material precursor composition is obtained;

[0068] (2) Preparation of the light-initiated foaming material: the light-initiated foaming material precursor composition is poured into a transparent mold, and is irradiated and cured by using a 254 nm ultraviolet lamp with a power of 100 W for 30 s. After the sample is cooled, the mold is removed, and the sample is placed at room temperature for 2 h for post-curing, and finally a high-resilience soft silicone modified epoxy foaming material is obtained.

[0069] As shown in Figure 4 , the prepared foaming material exhibits high compression resilience characteristics. The density of the high-resilience soft silicone modified epoxy foaming material is 0.20 g / cm 3 , the hardness is 8 shore A, the compression strength is 62 KPa Figure 5 , the T 5％ = 304.1 DEG C, and the residual mass at 1000 DEG C is 17% Figure 6 .

[0070] Example 3

[0071] The light-initiated foaming material of the present application comprises, by weight fraction, 40 parts of a polymer prepolymer E-51 type epoxy resin, 40 parts of a light-initiated foaming agent glycidyl ether type epoxy hyperbranched organosilicon resin, 5 parts of a light initiator triaryl sulfonium salt, 5 parts of a nucleating agent talc powder and 5 parts of calcium carbonate, and 5 parts of a filler hollow glass microsphere. The structural formula of the light-initiated foaming agent glycidyl ether type epoxy hyperbranched organosilicon resin is as follows:

[0072]

[0073] The preparation method of the photoinitiated foaming agent glycidyl ether epoxy-based hyperbranched organosilicon resin is as follows: 118 g (0.5 mol) of 3-glycidyl ether propyl trimethoxysilane, 120 g (0.5 mol) of phenyl triethoxysilane and 150 g of ethanol are weighed respectively, and are loaded into a three-necked flask with a condenser, a constant pressure dropping funnel and a thermometer, and are uniformly mixed, then 2.5 ml of hydrochloric acid with a concentration of 36.5 wt% is added dropwise, after the dropwise addition is completed, reflux reaction is carried out at 100°C for 6 h, after the reaction is completed, stirring is stopped, and the byproduct is removed by rotary evaporation at 55°C, to obtain an epoxy group-terminated hyperbranched organosilicon resin.

[0074] The preparation method of the photoinitiated foaming material is as follows:

[0075] (1) Preparation of the photoinitiated foaming material precursor composition: the raw materials are put into a round-bottom flask, and are mixed by stirring in the dark for 30 min, and are uniformly mixed by high-speed mixing, to obtain the photoinitiated foaming material precursor composition;

[0076] (2) Preparation of the photoinitiated foaming material: the photoinitiated foaming material precursor composition is poured into a transparent mold, and is irradiated by a 395 nm ultraviolet lamp with a power of 100 W for 60 s in a way of ultraviolet irradiation curing, after the sample is cooled, the mold is demolded, and is placed at room temperature for 1 h for post-curing, to finally obtain a slow-rebound semi-hard silicone modified epoxy foaming material.

[0077] As shown in Figure 7 , the prepared foaming material is a typical open-cell structure, and the pore size can be 10-1000 microns, and the foaming is uniform. It is tested that the density of the slow-rebound semi-hard silicone modified epoxy foaming material is 0.25 g / cm 3 , the hardness is 20 shore A, the compressive strength is 99 KPa Figure 8 , the T 5％ = 297°C, and the residual mass at 1000°C is 16.2% Figure 9 .

[0078] Example 4

[0079] The photoinitiated foaming material of the present application comprises, in terms of weight fractions, 5 parts of polymeric prepolymer Slin SL3401 polyurethane modified epoxy resin, 35 parts of photoinitiated foaming agent epoxy-based hyperbranched organosilicon resin, 3 parts of dialkyl-4-hydroxyphenyl sulfonium salt photoinitiator, 2 parts of ferrocene hexafluorophosphate, 40 parts of bis(1-ethyl(3-oxetanyl) methyl) ether as a structure control agent, 2 parts of alum as a nucleating agent, 3 parts of titanium dioxide, 5 parts of meteoric white carbon black as a filler, and 5 parts of glass fiber as an auxiliary agent; wherein the structural formula of the epoxy-based hyperbranched organosilicon resin is as follows:

[0080]

[0081] The preparation method of the photoinitiated foaming agent epoxy-based hyperbranched organosilicon resin is as follows: 118 g (0.5 mol) of 3-glycidyloxypropyltrimethoxysilane, 50.8 g (0.2 mol) of n-hexyltrimethoxysilane, 102 g (0.3 mol) of cyclohexyltrimethoxysilane, and 150 g of methanol are weighed into a three-necked flask equipped with a condenser, a constant pressure dropping funnel, and a thermometer, mixed uniformly, then 0.5 ml of 36.5 wt% hydrochloric acid is added dropwise, after the dropwise addition is completed, reflux reaction is carried out at 100 DEG C for 4 h, after the reaction is completed, stirring is stopped, and the byproduct is removed by rotary evaporation at 55 DEG C to obtain an epoxy-terminated hyperbranched organosilicon resin.

[0082] The preparation method of the photoinitiated foaming material is as follows:

[0083] (1) Preparation of the photoinitiated foaming material precursor composition: the raw materials are put into a round-bottom flask, mixed by stirring in the dark for 30 min, and then uniformly mixed by high-speed mixing to obtain the photoinitiated foaming material precursor composition;

[0084] (2) Preparation of the photoinitiated foaming material: the photoinitiated foaming material precursor composition is poured into a transparent mold, and a 405 nm ultraviolet lamp with a power of 100 W is used for irradiation for 30 s in the mode of ultraviolet irradiation curing, the sample is demolded after cooling, and post-curing is carried out at room temperature for 3 h to finally obtain a glass fiber reinforced soft organosilicon modified epoxy foaming material.

[0085] Example 5

[0086] The photoinitiated foaming material of the present application comprises, by weight fraction, 80 parts of a polymer prepolymer F-51 type epoxy resin, 5 parts of a photoinitiated foaming agent epoxy-based hyperbranched organosilicon resin, 3 parts of a photoinitiator sulfonyloxy ketone, 5 parts of a structure control agent trimethylolpropane glycidyl ether, 2 parts of a nucleating agent mica, 5 parts of a filler hollow glass microsphere, and 5 parts of a flame retardant dimethyl methylphosphonate; wherein the structure formula of the epoxy-based hyperbranched organosilicon resin is as follows:

[0087]

[0088] The preparation method of the photoinitiated foaming agent epoxy-based hyperbranched organosilicon resin is as follows: 172.2 g (0.7 mol) of 2-(3,4-epoxycyclohexyl), 70.2 g (0.3 mol) of n-octyltrimethoxysilane, 66 g (0.2 mol) of isobutyltriethoxysilane, and 150 g of ethanol are weighed into a three-necked flask equipped with a condenser, a constant pressure dropping funnel, and a thermometer, mixed uniformly, then 2.5 ml of 36.5 wt% hydrochloric acid is added dropwise, after the dropwise addition is completed, reflux reaction is carried out at 70 DEG C for 12 h, after the reaction is completed, stirring is stopped, and the byproduct is removed by rotary evaporation at 55 DEG C to obtain an epoxy-terminated hyperbranched organosilicon resin.

[0089] The preparation method of the light-initiated foaming material is as follows:

[0090] (1) Preparation of the light-initiated foaming material precursor composition: the raw materials are put into a round-bottom flask, mixed and stirred in the dark for 30 min, and then uniformly mixed at high speed to obtain the light-initiated foaming material precursor composition;

[0091] (2) Preparation of the light-initiated foaming material: the light-initiated foaming material precursor composition is poured into a transparent mold, and a 395 nm ultraviolet lamp with a power of 100 W is used for irradiation for 180 s. After the sample is cooled, it is demolded and placed at room temperature for 30 min for post-curing, and finally a hollow glass microsphere reinforced hard silicone modified epoxy foaming material is obtained.

[0092] Example 6

[0093] The light-initiated foaming material of the present application comprises, by weight fraction, 50 parts of polymer prepolymer F-51 type epoxy resin, 20 parts of light-initiated foaming agent epoxy-based hyperbranched silicone resin, 5 parts of light initiator ferrocene hexafluorophosphate, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylmethyl 12 parts of structure control agent, 2.5 parts of nucleating agent calcium oxide and 2.5 parts of magnesium oxide, 5 parts of filler hydrated zinc borate, and 3 parts of flame retardant ammonium polyphosphate; wherein the structural formula of the epoxy-based hyperbranched silicone resin is as follows:

[0094]

[0095] The preparation method of the light-initiated foaming agent epoxy-based hyperbranched silicone resin is as follows: 118 g (0.5 mol) of 3-glycidyl ether propyltrimethoxysilane, 33 g (0.25 mol) of n-propyltrimethoxysilane, and 87 g (0.25 mol) of n-hexadecyltrimethoxysilane are weighed, 150 g of toluene is added into a three-necked flask equipped with a condenser, a constant pressure dropping funnel, and a thermometer, and then mixed uniformly. Subsequently, 5 ml of 36.5 wt% hydrochloric acid is added dropwise, and after the addition is completed, the reaction is carried out at 80°C for 4 h. After the reaction is completed, the stirring is stopped, and the byproduct is removed by rotary evaporation at 55°C to obtain an epoxy-terminated hyperbranched silicone resin.

[0096] The preparation method of the light-initiated foaming material is as follows:

[0097] (1) Preparation of the light-initiated foaming material precursor composition: the raw materials are put into a round-bottom flask, mixed and stirred in the dark for 30 min, and then uniformly mixed at high speed to obtain the light-initiated foaming material precursor composition;

[0098] (2) The preparation of the photo-initiated foaming material: pour the photo-initiated foaming material precursor composition into a transparent mold, adopt the method of ultraviolet lamp irradiation curing, irradiate under the 100W 294nm ultraviolet lamp for 180s, demold after the sample is cooled, and place at room temperature for 33min for post-curing, finally obtain a hydrophobic flame-retardant silicone modified epoxy foaming material.

[0099] Example 7

[0100] The photo-initiated foaming material of the present application comprises, in parts by weight: 45 parts of polymer prepolymer F-51 type epoxy resin, 17 parts of photo-initiated foaming agent epoxy-based hyperbranched silicone resin, 5 parts of photo-initiator diphenyl-(4-phenylthio) phenyl sulfonium hexafluoroantimonate, 20 parts of structure control agent 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylmethylate, 5 parts of nucleating agent meteorological white carbon black, 5 parts of filler decabromodiphenyl ethane and antimony trioxide, and 3 parts of auxiliary agent ammonium polyphosphate; wherein the structural formula of the epoxy-based hyperbranched silicone resin is as follows:

[0101]

[0102] The preparation method of the photo-initiated foaming agent epoxy-based hyperbranched silicone resin is as follows: take 123g (0.5mol) 2-(3,4-epoxycyclohexane) trimethoxysilane, 71.2g (0.4mol) n-butyl trimethoxysilane, 29g (0.1mol) n-dodecyl trimethoxysilane, and 150g methanol, and load them into a three-necked flask with a condenser tube, a constant pressure dropping funnel, and a thermometer, mix them uniformly, then add 3ml of 36.5wt% hydrochloric acid drop by drop, after the dropwise addition is completed, reflux at 70℃ for 4h, after the reaction is completed, stop stirring, and remove the byproduct by rotary evaporation at 55℃, to obtain an epoxy-terminated hyperbranched silicone resin.

[0103] The preparation method of the photo-initiated foaming material is as follows:

[0104] (1) The preparation of the photo-initiated foaming material precursor composition: put the raw materials into a round-bottom flask, mix them uniformly under stirring in the dark for 30min, and then obtain the photo-initiated foaming material precursor composition;

[0105] (2) The preparation of the photo-initiated foaming material: pour the photo-initiated foaming material precursor composition into a transparent mold, adopt the method of ultraviolet lamp irradiation curing, irradiate under the 100W 365nm ultraviolet lamp for 30s, demold after the sample is cooled, and place at room temperature for 30min for post-curing, finally obtain a flame-retardant silicone modified epoxy foaming material.

[0106] Example 8

[0107] The raw materials of the light-initiated foaming material according to the present application include, in parts by weight, 55 parts of a polymer prepolymer F-51 type epoxy resin, 15 parts of an epoxy-based hyperbranched silicone resin selected as a light-initiated foaming agent, 5 parts of a photoinitiator diphenyl-(4-phenylthio) phenyl sulfonium hexafluoroantimonate, 10 parts of a structure control agent 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylacetate, 5 parts of a filler silicon powder, and 10 parts of an additive DeGussa AEROSIL R974 hydrophobic nano-silicon dioxide, wherein the structural formula of the epoxy-based hyperbranched silicone resin is as follows:

[0108]

[0109] The preparation method of the light-initiated foaming agent epoxy-based hyperbranched silicone resin is as follows: 123 g (0.5 mol) of 2-(3,4-epoxycyclohexane) trimethoxysilane and 82 g (0.5 mol) of n-propyl trimethoxysilane are weighed, 150 g of methanol is added, and a three-necked flask with a condenser tube, a constant pressure dropping funnel and a thermometer is used for mixing, followed by dropwise addition of 3 ml of concentrated hydrochloric acid with a concentration of 36.5 wt%, and after the dropwise addition is completed, reflux treatment is carried out at 120 DEG C for 3 h, after the reaction is completed, stirring is stopped, and the by-product is removed by rotary evaporation at 55 DEG C to obtain an epoxy-terminated hyperbranched silicone resin.

[0110] The preparation method of the light-initiated foaming material is as follows:

[0111] (1) Preparation of the light-initiated foaming material precursor composition: the raw materials are put into a round-bottom flask, mixed and stirred in the dark for 30 min, and then uniformly mixed by high-speed mixing to obtain the light-initiated foaming material precursor composition;

[0112] (2) Preparation of the light-initiated foaming material: the light-initiated foaming material precursor composition is poured into a transparent mold, and a 365 nm ultraviolet lamp with a power of 100 W is used for irradiation for 30 s in the mode of ultraviolet lamp irradiation curing, the sample is demolded after cooling, and post-curing is carried out at room temperature for 30 min, and finally a flame-retardant silicone-modified epoxy foaming material is obtained.

Claims

1. A photoinitiated foamed material, characterized in that, The raw materials include a polymer prepolymer, a photo-initiated foaming agent and a photo-initiator, wherein the photo-initiated foaming agent is an epoxy-based hyperbranched silicone polymer with a structural formula of ； wherein R is or one or a combination of both, R' is one or a combination of more than one of phenyl, methyl, n-propyl, n-hexyl, i-propyl, i-butyl, cyclohexyl, n-octyl, n-dodecyl, n-hexadecyl; the polymeric prepolymer is a polymer containing at least one epoxy group in the molecular chain.

2. The photoinitiated foamed material of claim 1, wherein, The photo-initiator is one or more of diazonium salt, diaryliodonium salt, triarylsulfonium salt, alkylsulfonium salt, iron arene salt, sulfonyloxy ketone and triarylsiloxane ether.

3. The photoinitiated foamed material of claim 1, wherein, The prepolymer is selected from F-51 type epoxy resin, and R of the epoxy-based hyperbranched organosilicon polymer is , and R' is methyl.

4. The photoinitiated foamed material of claim 1, wherein, The prepolymer is selected from E-44 type epoxy resin, R of the epoxy-based hyperbranched silicone polymer is , and R' is n-octyl.

5. The photoinitiated foamed material of claim 1, wherein, The prepolymer is selected from E-51 type epoxy resin, R of the epoxy-based hyperbranched silicone polymer is , and R' is phenyl.

6. The photoinitiated foam of claim 1, wherein, The raw materials of the foaming material further include one or more of reinforcing fillers, nucleating agents, structure control agents and flame retardants.

7. The photoinitiated foamed material of claim 6, wherein, The reinforcing fillers are one or more of glass fibers, weathered white carbon black, hollow glass microbeads, glass powder and silicon powder; the nucleating agents are one or more of talc, calcium carbonate, silicon dioxide, titanium dioxide and mica.

8. The photoinitiated foamed material of claim 6, wherein, The structure control agents are one or more of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexyl carboxylate, trimethylolpropane glycidyl ether, 1,6-hexanediol diglycidyl ether, phenyl glycidyl ether, 3-ethyl-3-hydroxymethyloxetane and bis(1-ethyl(3-oxetanyl)methyl)ether.

9. A process for the preparation of a photoinitiated foam according to any one of claims 1 to 8, characterized in that, The method comprises the following steps: (1) mixing the raw materials and pouring into a mold; (2) foaming and curing under the irradiation of an ultraviolet lamp to obtain the foaming material.

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