RU2688511C1 - Water-filled solid-phase polymer composite and method of its production - Google Patents

Abstract

FIELD: manufacturing technology.SUBSTANCE: invention relates to polymer composite materials having high fire-resistance, which can be used as structural materials, or means of protecting objects of various technical purposes from destructive effect of high temperatures in emergency situations accompanied by fire, by increasing time of the protected object achievement of the maximum critical temperature, at which the object loses operational properties. Water-filled solid-phase polymer composite based on polyester resin contains a stabilizing additive in the polymer matrix. Polymer matrix used is 48–81 vol% styrene-free polyester resin – a mixture of polyethylene glycol-maleinate phthalate and ethylene glycol methacrylate ester, with the following ratio of components, vol%: polyethylene glycol-malein phthalate – 40–45; methacrylic ether of ethylene glycol – 55–60; stabilizing additive is a fine-dispersed phase of free water uniformly distributed throughout the volume in amount of 17–50 vol% and additionally surface active substance bis-2-ethylhexyl-sulphosuccinate sodium – AOT in amount of 1–2 vol%.EFFECT: high heat-resistance and fire-retardant properties of the polymer composite.2 cl, 7 dwg, 5 ex

Description

The invention relates to polymeric composite materials with high fire resistance, which can be used as structural materials, or means of protecting objects of various technical purposes from the destructive effects of high temperatures in emergency situations accompanied by fire, by increasing the time the protected object reaches the maximum critical temperature at which the object loses operational properties.

The established and reflected in the existing standards requirements for fire resistance of materials used in construction and engineering, in general, cover a one-hour range of resistance to the action of a flame at temperatures up to 1000 ° C. So, according to the requirements of GOST 30247.0-94. “Building constructions. Test methods for fire resistance ", during a standard fire, the external surface of an object struck by fire is exposed to temperature effects in the range from 500 ° C to 1000 ° C for approximately 1.5 hours from the start of the fire.

According to the requirements of GOST R 50862-2012 "Safes, safe rooms and storage of valuables Requirements and test methods for resistance to cracking and fire resistance" the time to reach the critical temperature is determined by testing in accordance with the heating mode according to GOST 30247.0-94. Depending on the fire resistance class, the heat exposure time is 10-60 minutes.

Critical temperature, i.e. the temperature at which consumer and functional properties of an object deteriorate sharply and a significant change in its physicochemical properties occurs, determined by the type of object, the composition of its components, parts, structures, etc. So, to protect the structural elements of buildings and structures during a fire from aluminum alloys, it is necessary to maintain the temperature below 200 ° C, for steel structures - below 500 ° C. For the safety of safes (protection of paper documents) - below 170 ° С, for electronic equipment and memory cards - (70-100) ° С.

The above data indicates the need for insulating materials that ensure that the temperature of protected objects in the range of 70-150 ° C is maintained during a fire for at least 10-60 minutes, which is considered sufficient to eliminate the active phase of the fire, as well as to have a low smoke emission.

Currently, for this purpose, polymeric composites are widely used as the basis for thermo- and flame-retardant materials and structures. Conventionally, they can be divided into several groups:

- materials with low thermal conductivity (passive thermal protection), which have a low thermal conductivity and a certain thickness, which can be constant or change during a fire (intumescent materials);

- materials - coatings, or individual structures, with filling with fire retardant additives that suppress material burning due to the suppression or reduction of the rate of chain reactions of material burning, which is very sensitive to extraneous impurities (materials with fire retardants and special quenching additives);

- materials with high heat absorption (active heat protection) and heat resistance, including due to the chemical structure of the polymer component, which during temperature exposure undergo various physical and chemical transformations with a large endothermic effect: heating, melting, boiling, evaporation, destruction, chemical decomposition, etc. (materials with different chemical nature of polymeric binder).

A number of technical solutions are known that describe flame retardant materials that swell when heated. Thus, the known polymer composition containing oxidized graphite, and according to the invention, the material contains oxidized graphite with a degree of expansion of 50-400 (patent RU 2103314 from 01/27/1998, MKI C09K 21/14).

The disadvantage of this material is its inability to apply in a closed, limited volume, in the internal volumes of buildings for various purposes, for example, in transport packaging, designs that have fixed dimensions: doors, wall openings, bulkheads on ships, etc. Although it is successfully used as a coating of various metal structures, when there is an unlimited space where it can expand.

It is also known technical solution for the use of foamed fire-resistant polymeric composite materials containing perforated foamed polymer, the pores of which are filled with a filler based on an organosilicon polymer with a fire resistance of 200 to 700 ° C, a hardener, a stabilizer and a modifier. The porous base is filled with a liquid filler and cured thermally. The material holds a temperature of about 500 ° C for 30-40 minutes. (patent RU 2491318, published 08/27/2013, MKI C09K 21/14).

Also known is a variant of a flame-retardant polymer composite material based on a perforated foamed polymer base, the pores of which are filled with liquid synthetic rubber with a hardener and a flame retardant, and which is obtained by curing during the day. The fire resistance of the composition - at 1000 ° C - no more than 20-60 s, depending on the filler (patent RU 2430138, published 09/27/2011. MKI C09K 21/14).

The disadvantage of these materials is the need for a rather complex production technology and relatively low fire resistance, ability to ignite at temperatures of about 1000 ° C and smoke emission.

Also known technical solutions for obtaining fire-resistant polymer composite materials, where fire resistance is determined by the structure of the used polymer base, individual or filled with flame retardants. In this case, the flame retardants use either active, reacting with the base during combustion, or passive, which suppress the combustion chain reactions as radical scavengers.

So, fire-resistant polymer compositions are known for structural products based on resins of various structures:

- resistant to burning for several minutes and slightly fuming when burning on the basis of polybutylene terephthalate, polytetrafluoroethylene and block copolymer of butanediol with oligotetramethylene oxide with an organohalogen or antimony flame retardant (patent RU 2254349, published 06/20/2005, MKI C09K 21/14);

- flame retardant resin composition based on a complex polyester obtained from polylactic acid, polybutylene succinate, polycaprolactone, polytrimethylene terephthalate and flame retardant from phosphorylated polysaccharide; such products have fire resistance up to 800 ° C, formability and toughness (patent RU 2468051, published November 27, 2012, MKI C09K 21/14);

- non-combustible composite material based on epoxy diane resin and phenol formaldehyde resin, combined with a phosphate binder (with metals aluminum, aluminum chromium, boron aluminum); an organomineral polymer matrix with increased plasticity and incombustibility is obtained (patent RU 2598675, published 09/27/2016, MKI SKK 21/12, C08J 5/24);

- fire-resistant material based on ultrahigh molecular weight polyethylene (UHMWPE) of a fraction of 20-50 μm, mixed with ammonium polyphosphate of a fraction of 10 μm, obtained by pressing at elevated temperature (patent RU 2350642, published March 27, 2009, MKI C09K 21/14).

Also known are a number of technical solutions for producing flame-retardant polymer composites with fillers or reinforcing flame retardants.

Thus, compositions based on thermoplastic polymers with phosphorus-containing flame retardant additives are known, for example, based on a mixture of zeolite and aminotrismethylene phosphonic acid (patent RU 2252241, published 20.05.2005, MKI C09K 21/14); tin-containing dibutyl tin diacetate type fire retardants mixed with silanes incorporated into siloxane rubber (patent RU 2492201, published September 10, 2013, MKI C09K 21/14).

As reinforcing fire retardants in polymer composites, it is known to use layered structures comprising a porous fibrous material impregnated with a water-containing component. Thus, a laminate is known, with an external shock and heat resistant layer (of the ceramic coating type), then alternating layers of refractory porous fibrous material with low thermal conductivity of the type of mineral wool (passive thermal protection), and layers of porous fiber material impregnated with a water-based component based on water-soluble oligomers or polymers (active heat protection). (The patent of the Russian Federation №2162189 published January 20, 2001, MKI C09K 21/14). Thermal stabilization material of a single action for protection of an element of electronic equipment under the thermal effect of low-temperature flame, which is a nonwoven polymeric material impregnated with an aqueous solution of polyacrylamide with hemihydrate calcium sulphate, also belongs to this class of protection. (patent RU 2394868, published 07/20/2010, MKI C09K 21/14).

The disadvantage of this protection is the difficulty or impossibility of creating a large number of thin layers of material with a given total thickness, since the effectiveness of the entire protection depends on the number of successively boiling water-containing layers, and this reduces the overall effectiveness of protection, as well as the relatively low fire resistance.

The closest to the proposed technical solution adopted for the prototype is a heat-resistant polymer composite material obtained in two stages from the prepreg synthesized by the radiation method, followed by curing by vacuum-autoclave molding at 180-250 ° C.

The prepreg, at the first stage of the process, is obtained by treatment with ionizing radiation with a dose of 0.03-0.3 MGy (30-300 kGy) to the desired tackiness of the composite based on the stabilizing additive of the fibrous filler — glass or carbon fabrics, threads, tows impregnated with the composition, comprising: unsaturated polyether resin unsaturated polyester of maleate type in triethylene glycol dimethyl acrylate (polyether maleate phthalate), modified with a solution of cobalt n-butyl phthalate in oligoether acrylate, or epoxy acrylate, triallyl cyanurate or riallilizotsianurat in a ratio to the resin 58,6-66,7: 33,3-41,4 wt. %, respectively, as well as an additional epoxy resin (epoxy Novolac phenolic-bakelite resin) with a hardener - boron trifluoride complex with aniline. (patent RU 2304591, published 08/20/2007, MKI C08J5 / 24).

The disadvantages of the technical solution of the prototype are the complexity of the technology for producing composite material - a two-stage technology: the first stage is the synthesis of prepreg under the influence of ionizing radiation, the second stage is the processing of the prepreg into the product under elevated temperatures, and a relatively low fire and fire resistance is noted: only the ability to work for a long time at 150-200 ° C. The heat resistance of the obtained composite material according to the patent is 200-230 ° C.

The aim of the present invention is to develop a water-filled solid-phase polymer composite with improved thermal and flame retardant properties and a method for producing it in one stage in any desired form.

An object of the invention is to create a solid-phase polymer composite material, where as the main fire and fire suppressant substance is a flame retardant, water is used in a mycelial state in the composite body. Such a water-filled polymer composite with high thermal and flame-retardant properties simultaneously provides layer-by-layer boiling of water, preventing the burning of the polymer component of the material and promoting the formation of a coke porous layer with low thermal conductivity when exposed to high temperatures during a fire. The technical solution of the method of obtaining this composite is radiation-chemical synthesis.

The technical result of the invention is to improve the heat resistance and flame retardant properties of the polymer composite.

FIG. 1 - Scheme of the experiment to measure the heat resistance of the polymer composite. The arrows indicate the direction of the flame of the burner.

FIG. 2 - Photograph of fire tests of the polymer composite (side view).

FIG. 3 - Photograph of fire tests of a polymer composite (sample after 1 hour of exposure to high temperature)

FIG. 4 - Change in temperature rise during fire exposure to a flame (1000 ° С) at a sample depth of 10 mm from the impact surface.

FIG. 5 - Change in temperature rise at fire exposure to flame (1000 ° C) at a sample depth of 10 mm from the impact surface for a composite polymer material with a water content of 36% by volume

FIG. 6 - Temperature variation in the thickness of two polymer composite samples with a water concentration of 50% at a depth of 10 mm under the influence of a burner flame (t = 800 ° C).

FIG. 7 - Shot hardness depending on the dose of radiation

When exposed to temperature during a fire, the following endothermic processes occur in the proposed material: the outer layer is heated to the boiling point of water, boiling of water occurs at a temperature of about 100 ° C, therefore the deeper layer is exposed to the boiling point. After all the water in the outer layer turns into steam, the pressure rises above the strength of the outer polymer layer and the outer layer of the polymer matrix collapses, thermal decomposition and decomposition of the polymer occur with the formation of coke porous material. After this, the inner layer is heated, but already at lower heat fluxes, since coke protection has already formed. And further, these processes of layer-by-layer heating, boiling, destruction of the outer layer and coking continue until the process of vaporization is completed in the layer opposite to fire.

The time interval from the beginning of the fire exposure to the time it reaches the critical temperature of the protected object depends on both the amount of water in the dispersed phase of the composite and the size of water droplets. The more crushed the dispersed aqueous phase and the more water is contained in the polymer composite, the longer the low temperature at the protected object is maintained during a fire.

The thermal conductivity of the material obtained was measured by the flat layer method (plate method) using the measurement method for building boards using an electronic thermal conductivity meter ITP MG4 "100" under conditions of temperature of about 800 ° C for 3 samples) Thermal conductivity values in dimensions W / (m * s) amounted to 0.035-0.041.

The method of obtaining a solid-phase polymer composite consists in the sequential preparation of an emulsion from a liquid resin and water by dispersing, followed by pouring into the desired shape (sheet, cylinder, sphere, or any other complex form), and further radiation curing, either when exposed to gamma radiation or exposure to a stream of accelerated electrons.

Examples of obtaining a water-filled solid-phase polymer composite.

Example 1

The polymer composition was prepared by mixing styrene-free polyester resin, which is a product of mixing 40% polyethylene glycol-maleinate phthalate with 60% methacrylic ether of ethylene glycol in an amount of 81% by volume and water, in an amount of 17% by volume. To obtain a stable and finely dispersed emulsion (“water in oil”), sodium bis-2 ethylhexyl sulfosuccinate was used as a surfactant in an amount up to 2% of the volume of water.

The components were mixed using a mechanical multi-blade mixer at speeds from 500 to 800 rpm. The prepared emulsion was poured into a rectangular shape with a flat bottom and a side of 25 mm. Thickness of the cast layer up to 25 mm. Then the emulsion was irradiated in the indicated form with gamma radiation from a cobalt-60 radionuclide to an absorbed dose of 15 kGy for complete polymerization. Received two flat samples with a thickness of 20 mm.

The method of flat layer (plate method) measured the thermal conductivity of the material obtained according to the measurement method for building boards using an electronic thermal conductivity meter ITP MG4 "100" under conditions of temperature of about 800 ° C for 3 samples). The values of the thermal conductivity coefficient in the dimension W / (m * s) were 0.035-0.041.

Conducted determination of the indentation of the sample hardness using a TN-210 Shore hardness tester (according to ISO 868 for the case of plastics). The values obtained were in the range of 64.7-68.4.

Fire tests were carried out on the cured samples of the composite. The dimensions of the test specimen, in the form of a flat plate (1) were 54 (37 (20 mm), in the body of the sample at a depth of 10 mm from the heated surface, a hole (2) with a depth of 10 mm was drilled from the surface of the 54 × 37 surface to accommodate a thermocouple. using an air burner flame from the opposite side. A glass blowing gas burner with air blowing was used as a fire source. The flame temperature was maintained at 800 ° C. During the test, the temperatures on the surface of the material opposite to flame and at a depth of 10 mm composite layer (at half the sample thickness) .To reduce heat transfer from the burner to the thermocouple, located on the back of the sample, bypassing the sample thickness, the sample was insulated at the edges with asbestos fiber (3). 1. The photo of the experiment is shown in Fig. 2. The test results of sample No. 1 of the proposed protective material are shown in Fig. 4: curve 4 — PN-609M resin without water; curve 5 - declared composite (sample No. 1), containing 17% of the fine phase of free water; curve 6 - the declared composite (sample No. 2) containing 29% of a fine phase of free water ;.

As can be seen from the test results, when using the proposed material with a thickness of 10 mm with a water content of 17% when exposed to a flame with a temperature of 800 ° C at a protected object (inside, for example, a safe), the temperature below 120 ° C will be maintained for about 7 minutes. And the temperature is below 170 ° C - 9 min. At the same time, on the reverse side of the sample (thickness of a full layer of 20 mm) the temperature during the experiment did not exceed 43 ° C.

Example 2

The polymer composition was prepared analogously to example 1 by mixing a styrene-free polyester resin, which is a product of mixing 45% polyethylene glycol-maleate phthalate with 55% ethylene glycol methacrylic ether (oligoether acrylate TGM-3) in an amount of 70% by volume and water, in an amount of 29% by volume. To obtain a stable and finely dispersed emulsion (“water in oil”), sodium bis-2 ethylhexyl sulfosuccinate was used as a surfactant in an amount up to 1% of the volume of water.

The prepared emulsion was poured into a circular flat shape like a Petri dish. The thickness of the cast layer is 22 mm. Then, gamma radiation from the cobalt-60 radionuclide was irradiated with an absorbed dose of 20 kGy for complete polymerization. Received two flat samples with a thickness of 18 mm. Shore hardness is about 50. The firing tests were carried out on hardened samples of the composite with a diameter of 105 mm and a thickness of 18 mm using a scheme similar to that in Example 1. The thermocouple was mounted similarly to example 1. The test results of sample No. 2 of the proposed protective material are presented in FIG. 4 (curve 6).

When exposed to a flame with a temperature of 800 ° C, for 9 minutes the temperature at a depth of 10 mm reached 135 ° C. On the back side of the sample, the temperature did not rise above 45 ° C.

For comparison, it should be noted that the obtained anhydrous cured composition based on the same polyester resin can withstand 4 minutes to a temperature of 135 ° C (Fig. 4, curve 4).

Example 3

The polymer composition was prepared analogously to example 1 by mixing a styrene-free polyester resin, which is a product of mixing 45% polyethylene glycol-maleate phthalate with 55% ethylene glycol methacrylic ether (oligoether acrylate TGM-3) in an amount of 62.5% by volume and water, in an amount of 36% by volume . To obtain a stable and finely dispersed emulsion (“water in oil”), sodium bis-2 ethylhexyl sulfosuccinate was used as a surfactant in an amount up to 1.5% by volume.

The prepared emulsion was poured into a rectangular flat shape — 200x200 mm. The thickness of the cast layer is 12 mm. Then, gamma radiation from the cobalt-60 radionuclide was irradiated with an absorbed dose of 23 kGy for complete polymerization. Received two flat samples with a thickness of 10 mm.

Measured Shore Hardness -52.

The fire tests were carried out on hardened samples of the composite 200x200 mm and 10 mm thick in a manner similar to Example 1, but the thermocouple was mounted on the opposite side of the flame plate of the composite plate as in Example 1 at depth. The test results of sample No. 4 of the proposed protective material are presented in FIG. five

When exposed to a flame with a temperature of 1000 ° C, the temperature on the reverse side of the plate with a thickness of 10 mm reached 105 ° C for 45 minutes. After 55 minutes of exposure, the temperature reached 150 ° C, and after 59 minutes the impact burned the plate.

In the course of the experiment, no harmful evaporation was observed, there was practically no smoke, evaporation of water into steam, carbonization of the material occurred (see Fig. 3). Melting of the material was not observed. Mechanical failure of the experimental sample was not observed.

Example 4

The polymer composition was prepared analogously to example 3 by mixing a styrene-free polyester resin, which is a product of mixing 45% polyethylene glycol-maleate phthalate with 55% ethylene glycol methacrylic ether (oligoether acrylate TGM-3) in an amount of 48% by volume and water in an amount of 50% by volume. To obtain a stable and finely dispersed emulsion (“water in oil”), sodium bis-2 ethylhexyl sulfosuccinate was used as a surfactant in an amount up to 2% by volume. The prepared emulsion was poured into two rectangular flat shapes - 200 × 200 mm. The thickness of the cast layer is 22 mm. Then, each form was irradiated with an emulsion with a beam of accelerated electrons with an energy of 8.5 MeV in a plane perpendicular to the surface of the emulsion, picking up a dose of 25 kGy in the sequential double irradiation mode for complete polymerization. Received two flat samples with a thickness of 18 mm. Shore hardness is 47 and 45.

Fire tests were carried out on the cured samples of the composite 200x200 mm and 10 mm thick in a manner similar to Example 1.

The results of testing samples No. 5 and 6 of the proposed protective material are presented in FIG. 6 (curves 7 and 8, respectively). The scatter of the fire resistance data (time intervals / temperature) of the samples does not exceed 5-7% and is associated with experimental errors caused by two separate exposures, as well as a possible variation of the sample thickness.

As follows from Fig. 6, the samples withstand exposure to the flame of a hydrogen burner for at least 40 minutes, without burning, smoke emission and mechanical destruction, only layer-by-layer ashing of the surface exposed to the flame occurs.

Example 5

Conducted studies of the dependence of the parameters of the hardness of the composite on the magnitude of the absorbed dose of radiation in the mode of gamma irradiation of the radioisotope cobalt-60.

The polymer composition was prepared analogously to example 3 by mixing a styrene-free polyester resin, which is a product of mixing 45% polyethylene glycol-maleate phthalate with 55% ethylene glycol methacrylic ether (oligoether acrylate TGM-3) in an amount of 62.5% by volume and water, in an amount of 36% by volume . To obtain a stable and finely dispersed emulsion (“water in oil”), sodium bis-2 ethylhexyl sulfosuccinate was used as a surfactant in an amount of up to 1.5% by volume.

The prepared emulsion was poured into 15 round flat forms with a diameter of 30 mm. Irradiation was performed in 3 samples with doses of 5.0; 10.0; 15.0; 20.0 and 25.0 kGy. Shore hardness was measured using a TH210 hardness tester (scale D). The results are presented in the form of a histogram in FIG. 7 As follows from the measurement results, the hardness of the obtained composite in the dose range of 15-25 kGy is within acceptable limits: HS (D) = 70-80, which corresponds to the classification of solid material.

Thus, the proposed material is quite suitable for use in the manufacture of non-combustible fire-retardant wall panels, for example, ship bulkheads, for the walls of packaging transport containers for the transport of radioactive materials, fire-resistant safes for storing securities.

Claims (2)

1. A water-filled solid-phase polymer composite based on polyester resin containing a stabilizing additive in a polymer matrix, characterized in that it contains 48-81% by volume of a styrene-free polyester resin as a polymer matrix — a mixture of polyethylene glycol-maleate phthalate and ethylene glycol methacrylic ether in the following ratio of components ,%: polyethylene glycol-maleate phthalate - 40-45; ethylene glycol methacrylic ether - 55-60; as a stabilizing additive - uniformly distributed throughout the volume of the fine phase of free water in the amount of 17-50 vol.% and additionally surface-active substance sodium bis-2-ethylhexyl-sulfosuccinate - AOT in the amount of 1-2 vol.%. 2. A method of obtaining a water-filled polymer composite, comprising sequentially preparing the original prepreg, pouring it into the form established by the manufacturer and subsequent curing, characterized in that a stable water-polymer emulsion is obtained as a starting prepreg by dispersing the microdroplets of water in suspension by stirring in a mass of styrene-free polyester resin in the presence of a surfactant in ratios according to claim 1, and the curing of the emulsion is carried out with radiation-chemical by irradiation with gamma radiation or a beam of accelerated electrons with an absorbed dose of 15-25 kGy.

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