RU2722596C1 - Binding composition for producing insulating composite material and insulating composite material - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: group of inventions relates to a binder composition for producing a composite material and to an insulating material which can be used for insulating pipes, walls and channels of heating mains or ventilation channels and various parts used in conditions of high temperatures and high pressure. Binder composition for producing insulating composite material contains binder, hydrophobic particles of aerogel and hollow non-porous particles, ammonium polyphosphate and cationic surfactant (CS). Cationic surfactant is a quaternary ammonium salt - a mixture of alkyldimethylbenzylammonium chlorides, where alkyl is a mixture of normal alkyl radicals. At that, surfactant is cladded in amount of 0.1–2 wt. % of weight of binder. Composition contains the following ingredients, wt. %: hydrophobic aerogel particles and hollow non-porous particles 45–55; ammonium polyphosphate 20–30; cationic surfactant (CS) 8–10; binder making the rest.

EFFECT: invention improves heat conductivity, heat resistance and hydrophobicity of the insulating composite material.

3 cl, 5 tbl, 1 dwg

Description

The invention relates to the creation of insulating materials that can be used to insulate pipes, walls and ducts of heating mains or ventilation ducts and various parts used under conditions of elevated temperatures and high pressure, providing thermal stability, mechanical strength and / or flexibility.

BACKGROUND OF THE INVENTION

The prior art is known for HEAT-RESISTANT INSULATING COMPOSITE MATERIAL AND METHOD FOR PRODUCING IT. (Patent IZ. No. 2303744 from 07.27.2007).

Heat-resistant insulating composite material is:

(a) an insulating base layer containing hollow non-porous particles and a binder matrix, and

(b) a heat-reflecting layer containing an infrared reflecting agent and a protective binder, the heat-resistant insulating composite material having a thermal conductivity of about 0.050 W / (m ² · K) or less.

The closest in technical essence and the achieved result is “BINDING COMPOSITION CONTAINING AEROGEL AND HOLLOW PARTICLES, INSULATING COMPOSITE MATERIAL AND METHOD FOR PREPARING THEM” (Patent FROM No. 2315071 from 01.20.2008).

An insulating composite material and a binder composition with airgel and hollow particles can be used to isolate, for example, parts of motorized vehicles or devices, providing thermal stability, mechanical strength and / or flexibility.

The binder composition of the prototype contains airgels made of silicon dioxide, titanium dioxide and alumina. Hydrophobic airgel particles may contain silencers that reduce the thermal conductivity of hydrophobic airgel particles. Any suitable silencers can be used: wax, paraffins, soot, carbon fiber, titanium dioxide and modified carbon components.

According to the invention, any type of hollow, non-porous particles is used in the prototype, including materials called microspheres, micro bubbles, microscopic hollow balls, cenospheres.

Hollow non-porous particles can be made of any suitable material, including organic and inorganic materials, preferably they are made of a material with relatively low thermal conductivity. Organic materials include, for example, vinylidene chloride / acrylonitrile copolymers, phenolic materials.

They are made of a material with relatively low thermal conductivity (aluminosilicate microspheres - 0.1 W / m ² K, ceramic microspheres - 0.034 W / m ² K, foams (poroplastics) - 0.043 W / m ² K.

The protective layer gives a higher degree of mechanical strength to the insulating composite material and protects the lower insulating layer from destruction due to one or more environmental factors (e.g., heat, humidity, friction, shock, etc.). A protective binder can be any suitable binder that is resistant to the specific conditions (e.g., heat, load, humidity, etc.) to which the insulating composite material will be exposed. Thus, the choice of binder will depend in part on the specific properties desired in the insulating composite. The protective binder may be the same as the binder of the lower insulating layer, or different. Suitable binders include aqueous and non-aqueous natural and synthetic binders. Self-crosslinking binders, such as self-crosslinking acrylic binders, are particularly preferred. The protective layer may contain almost no or no hollow non-porous particles. in an amount of about 20 vol.% or less, such as about 10 vol.% or less, or even about 5 vol.% or less (for example, about 1 vol.% or less).

An infrared light reflecting agent can be any compound or composition that reflects or otherwise blocks infrared radiation, including a silencer, such as carbon materials (e.g. carbon black), carbon fibers, titanium dioxide (rutile) and metallic and non-metallic particles, pigments and fibers and mixtures thereof. Preferred infrared light reflecting agents include metal particles, pigments and pastes such as aluminum, stainless steel, copper-zinc alloys and copper and chromium alloys. Particularly preferred are aluminum particles, pigments and pastes. In order to prevent deposition of the infrared light reflecting agent in the protective binder, the protective layer advantageously contains an antioxidant, for example, colloidal metal oxides, clays and organic suspending agents. Preferred antioxidants are colloidal metal oxides, such as colloidal silicon dioxide, and clays, such as hectorites. The protective layer may also contain a wetting agent, such as a non-foaming surfactant.

Preferred protective layer formulations contain reinforcing fibers.

The technical problem to which the invention is directed is the production of an insulating composite material, which provides many of the advantages of insulating materials containing airgel (for example, good heat and / or sound insulation), and with improved wear resistance and heat resistance.

The technical result compared with the prototype provided by the developed invention is to improve the thermal conductivity, heat resistance and hydrophobicity of the material.

The technical problem is solved and the technical result is achieved by developing a binder composition, to obtain an insulating composite material that contains a binder, hydrophobic airgel particles and hollow non-porous particles, and additionally includes ammonium polyphosphate and a cationic surfactant (QUAS), which is a quaternary ammonium salt - a mixture of alkyldimethylbenzylammonium chlorides, where alkyl is a mixture of normal alkyl radicals, while the surfactant is taken in an amount of 0.1-2 wt. % by weight of a binder in the following ratio of ingredients, wt. %:

hydrophobic airgel particles and hollow non-porous particles 45 - 55

ammonium polyphosphate 20-30

cationic surfactant (CAS) 8-10

binding rest.

The cationic surfactant (CAS) is dimethylcobenzylammonium chloride (MCB-80), a molecular weight of 350, a density of 0.98 g / m ³ , and a viscosity of 75 mPaПs.

The technical result is also achieved by the fact that the insulating composite material contains a main insulating layer based on a binder composition comprising airgel particles and hollow non-porous particles, a binder and additionally ammonium polyphosphate and a cationic surfactant. Moreover, the insulating layer is characterized by a density of not less than 157 kg / m ³ and a thermal conductivity of the layer of not less than 0.035 W / m ² K and an external heat-reflecting layer containing an aqueous acrylic binder, hollow non-porous particles in an amount of not more than 20 vol. %, ammonium polyphosphate and aluminum powder as an agent reflecting infrared light, while the thermal conductivity of the insulating composite material after drying is not more than 0.060 W / m ² K.

The use of ammonium polyphosphate and surfactant in the composition together with the declared other ingredients of the binder composition to obtain the main insulating layer leads to the achievement of a technical result - an improvement in the thermal conductivity, heat resistance and hydrophobicity of the insulating composite material.

Aerogels are known to provide excellent heat and sound insulating properties. Airgel-containing insulation materials are prepared by mixing dry airgel particle compositions with binders to form a bound mass of particles. Also, binder compositions with airgel, providing good heat and sound insulation, can exhibit low wear resistance and thermal degradation at high temperatures.

The invention provides a binder composition with airgel and hollow particles, mainly consisting of an aqueous binder, hydrophobic particles of airgel, hollow non-porous particles, ammonium polyphosphate and cationic surfactant (CPAS).

The invention also provides an insulating composite material mainly consisting of a main insulating layer and a protective layer consisting of a binder, hydrophobic airgel particles, hollow non-porous particles, ammonium polyphosphate and an infrared light reflecting agent. The resulting insulating composite material has additional waterproofing, heat-insulating and heat-reflecting effects, as well as fire-fighting properties.

A method of preparing a binder composition with an airgel and hollow particles, mainly consisting of an aqueous binder, ammonium polyphosphate and surfactant, shaking the binder composition and joining the foamed binder composition with hydrophobic airgel particles and hollow non-porous particles to obtain a binder composition with airgel and hollow particles.

DETAILED DESCRIPTION OF THE INVENTION

The binder composition with airgel and hollow particles contains an aqueous binder, hydrophobic airgel particles, hollow non-porous particles, ammonium polyphosphate and cationic surfactants.

All surfactants can be divided into two large groups - nonionic and ionic.

Ionogenic substances in water solutions dissociate into ions. According to the charges of ions, they can be divided into: anionic, cationic and amphoteric. Cationic (acidic) are those compounds in which aqueous solutions are determined by cations (ions with a positive charge).

The surfactant used in this composition refers to cationic surfactants and is a quaternary ammonium salt - a mixture of alkyl dimethylbenzylammonium chlorides, where alkyl is a mixture of normal alkyl radicals. Correlates with a group of cationic surfactants. In concentrated form it has the form of a viscous liquid with a faint specific odor, with unlimited solubility in water.

Dimethyl cocobenzylammonium chloride (MCB-80), molecular weight 350, density 0.98 g / m ³ , viscosity 75 mPa · s.

The combination of the claimed ingredients of the binder composition leads to the achievement of a technical result - an improvement in the thermal conductivity, heat resistance and hydrophobicity of the insulating composite material.

CPAS improves adhesion between hydrophobic airgel particles and an aqueous binder. Also, the surfactant improves the rheology of the aqueous binder (e.g., in spray applications) and, in particular, allows the binder to foam when the combined binder and surfactant are mixed or agitated (e.g., foaming) before or after the introduction of hydrophobic airgel particles and / or hollow non-porous particles. In addition, the surfactant is used to obtain a foamed binder composition with airgel and hollow particles having a lower density than the non-foamed composition.

Preferably, about 0.1 to 2 wt. %, Surfactant by weight of the binder.

The thermal conductivity of the binder composition with airgel and hollow particles will partially depend on the specific formulation used to obtain the lower insulating layer. Preferably, the lower main insulating layer is formed so that after drying it has a density of less than 157 kg / m ³ , thermal resistance less than 0.20 m ² K / W and thermal conductivity of the layer less than 0.037 W / (m ² * K).

Insulating Composite Material

The lower insulating layer may have any desired thickness. Insulating composite materials containing thicker lower insulating layers have better heat and / or sound insulating properties; however, the insulating composite material in accordance with the invention allows the use of a relatively thin lower insulating layer, nevertheless providing excellent heat and / or sound insulating properties. For most applications, the lower insulating layer with a thickness of about 1-15 mm, such as, for example, about 2-6 mm, provides sufficient insulation.

The protective layer gives a higher degree of mechanical strength to the insulating composite material and / or protects the lower main insulating layer from destruction due to one or more environmental factors (e.g., heat, humidity, friction, impacts, etc.). A protective binder can be any suitable binder that is resistant to the specific conditions (e.g., heat, load, humidity, etc.) to which the insulating composite material will be exposed. Thus, the choice of binder will depend in part on the specific properties desired in the insulating composite. Binders are aqueous binders, such as aqueous acrylic binders. Self-crosslinking binders, such as self-crosslinking acrylic binders, are particularly preferred.

An infrared light reflecting agent can be any compound or composition that reflects or otherwise blocks infrared radiation, including a silencer, such as carbon materials (e.g. carbon black), titanium dioxide (rutile) and metallic and non-metallic particles, pigments and mixtures thereof. Preferred infrared light reflecting agents include metal particles, pigments and pastes such as aluminum, stainless steel, copper-zinc alloys and copper and chromium alloys. Particularly preferred are aluminum particles, pigments and pastes.

The thickness of the protective layer will depend in part on the degree of protection and the desired strength. Although the protective layer can be of any thickness, it is often desirable to keep the thickness of the protective insulating composite material to a minimum and thus reduce the thickness of the protective layer to the minimum necessary to provide a sufficient degree of protection for a particular application. Typically, sufficient protection can be provided by a protective layer with a thickness of about 1 mm or less.

The thermal conductivity of the insulating composite material will primarily depend on the particular formulation of the lower main insulation layer, although the protective layer formulation may also have some effect. Preferably, the insulating composite material is designed to have a thermal conductivity of less than 0.060 W / (m ² K) after drying.

The insulation composite is heat resistant. The term “heat-resistant” as used to describe an insulating composite material of the invention means that the insulating composite material will not noticeably decompose under conditions of intense heating. In particular, conditions of strong heating are ensured by the use of a 250 W heating element connected to a hot blower with thin aluminum panels mounted around the pipe forming apparatus. The insulating composite material is subjected to strong heating (protective layer facing the heating element) at a distance of about 20 mm from the heating element, in which the hot blower (when fully installed for blowing and lower installation for heating) provides a continuous flow of air between the heating element and the insulating composite material. It is desirable that the insulating composite material does not deteriorate noticeably under such conditions.

If the insulating composite material is to be used in a particular class of flammability, for example, where it may be exposed to open flames or at extremely high temperatures, it is desirable that the insulating composite material include a suitable flame retardant. Fire retardant may be included in the protective layer of the insulating composite material. Suitable flame retardants include aluminum hydroxides, magnesium hydroxides, ammonium polyphosphates and various phosphorus-containing substances, and other commercially available flame retardants, and intumescent fire retardants.

A method of preparing a binder composition of an insulating composite material is as follows: a binder composition with airgel and hollow particles can be obtained by any suitable method. For example, hydrophobic airgel particles, hollow non-porous particles and an aqueous binder can be combined in any suitable way to form a binder composition with airgel and hollow particles, which can be applied to the substrate, for example, by spreading, extruding or spraying a binder composition with airgel and hollow particles on the basis of.

In accordance with the invention, there is provided a method of preparing a binder composition with airgel and hollow particles and other ingredients, which can be used to obtain the lower main insulation layer to obtain an insulating composite material. In particular, a binder composition with an airgel and hollow particles obtained according to the invention has a reduced tendency to “wet” the airgel particles and / or hollow non-porous particles, thereby reducing the tendency of the airgel particles and / or hollow non-porous particles to separate from the composition. In addition, the method in accordance with the invention provides a binder composition that can be sprayed.

The invention is illustrated by examples with different content of surfactants by weight of the binder.

Example 1

This example illustrates the preparation and characteristics of a binder composition with an airgel and hollow particles according to the invention.

A binder composition was prepared by combining 200 g. (15 wt.%) aqueous acrylic binder (Acrylic dispersion CHP 536 (Finland)), 133 g (10 wt.%) CPAS (Alkyl dimethylbenzylammonium chloride “Catamine AB”), in a high-speed mixer. The binder composition was mixed until 4 dm was obtained.³foamed binder composition. Hydrophobic airgel particles and hollow non-porous particles containing 300 g of muffled hydrophobic balls of airgel, 300 g of glass microspheres (45 wt.%) And 400 g (30 wt.%) ammonium polyphosphate, was slowly added with stirring, to maintain the volume at a value of 4 dm³, thereby obtaining a binder composition with airgel and hollow particles.

The sample was applied to a frame measuring 25 cm × 25 cm, having a thickness of 1.5 cm using a spatula. The frames were lined with aluminum foil. The composition was dried for 18 hours at 74 ° C. After the compositions had cooled, 15 cm × 15 cm samples were cut from the frames, and the thermal conductivity of each sample was measured on a device to determine thermal conductivity with an upper plateau temperature of 36 ° C and a lower plateau temperature of 10 ° C. Density of the samples was determined by dividing the weight of each sample by its size.

The results are shown in Table 1.

Table 1 Sample A type Density (kg / m³) Thermal Resistance (m²K / W) Thermal Conductivity (W / m²K) 1 Airgel / Microspheres / Acrylic / Polyphosphate / CPAS (10%) 244 0.24 0,043

These results show that, according to the invention, a binder composition with airgel and hollow particles can be prepared, which has good thermal conductivity, thermal resistance and low density.

Example 2

The binder composition was prepared by combining 200 g (16 wt.%) Of an aqueous acrylic binder (Acrylic dispersion CHP 536 (Finland), 113 g (9 wt.%) CPAS (Alkyl dimethylbenzylammonium chloride “Catamine AB”), 325 g of muffled hydrophobic airgel beads and 300 g of glass microspheres (50 wt.%), 313 g of ammonium polyphosphate (25 wt.%) were slowly added with stirring, thereby obtaining a binder composition with airgel and hollow particles.

The results are shown in Table 2.

table 2 Sample A type Density (kg / m³) Thermal Resistance (m²K / W) Thermal Conductivity (W / m²K) 2 Airgel / Microspheres / Acrylic / CPAA (9%) 157 0.20 0,035

Example 3

A binder composition was prepared by combining 200 g (17 wt.%) Of an aqueous acrylic binder (Acrylic dispersion CHP 536 (Finland), 94 g (8 wt.%) CPAS (Alkyl dimethylbenzylammonium chloride “Catamine AB”). Then 347 g of muffled hydrophobic balls of airgel, 300 g of glass microspheres (55 wt.%), 235 g (20 wt.%) of ammonium polyphosphate, thereby obtaining a binder composition with airgel and hollow particles.

The results are shown in Table 3.

Table 3 Sample A type Density (kg / m³) Thermal Resistance (m²K / W) Thermal Conductivity (W / m²K) 3 Airgel / Microspheres / Acrylic / Polyphosphate / CPAS (8%) 357 0.26 0,054

The process of obtaining an insulating composite material as a whole consists of two stages:

1. Spraying the lower main insulating layer on the surface of the product with a coolant. Layer thickness 5-20 mm.

2. Application of an external heat-reflecting layer on the surface of the insulating layer, by spraying or with a brush. Layer thickness 1-10 mm.

A binder composition of the external heat-reflecting layer was prepared by combining 200 g of an aqueous acrylic binder (Acrylic dispersion CHP 557 (solids 60%, MFFT, 0 ° C, Particle size, 500 Nm), 4 g aluminum powder (AVL Metal Powders, density 0.22 -0.32 g / cm ³ , Average particle size 21-175 μm, Covering ability on water 4500-6500 cm ² / g), in a mixer, Then 50 g of glass microspheres and 100 g of ammonium polyphosphate are introduced. until you get a homogeneous mass.

The thermal conductivity of the insulating composite material is 0.060 W / m²K

Each of the insulating composite materials was placed in an apparatus designed to determine the heat resistance of the insulating composite material. In particular, the device included a 250 W heating element connected to a hot blower with thin aluminum panels mounted around the device to form a pipe. The insulating composite material was subjected to strong heating for about 30 minutes at a distance of about 20 mm from the heating element (protective layer facing the heating element), and a hot blower (when installed on a full blow and lower installation on heating) provided a continuous flow of air between the heating element and insulating composite material. The temperature of the reverse side of the insulating composite material (i.e., the side opposite the protective layer and the heating element) was monitored throughout the test to determine the maximum supported temperature.

The results of these measurements are shown in table 4.

Table 4 No. p / p Sample Name Test Time (min.) Surface temperature (° C) 1 composite material (0.1% CPAS) thirty 42 2 composite material (1% CPAS) thirty 26 3 composite material (2% CPAS) thirty 33

Indicators of hydrophobicity of the insulating composite material.

Table 5 Sample A type Density (kg / m³) α - hydrophobicity 1 composite material (1% CPAS)
Sample 37 157 ≥110 ° 2 composite material (2% CPAS) Sample 56 257 ≥ 90 °

Based on the above results given in the tables, the following conclusions can be drawn that the insulating composite material consisting of two layers (the main insulating and protective), due to the combination of its constituent components and the use of ammonium polyphosphate and surfactant in the composition of the material, provides a technical result. The indicators of thermal conductivity, heat resistance and hydrophobicity of the material are improved.

A graph of the moisture absorption of the material is shown in FIG. 1.

Where, days of the test, along the axis of the abscess: Weight of the sample material (in g) immersed in water. The upper curve shows the amount of moisture absorption by the material (sample 56). The lower curve shows the amount of moisture absorption by the material (sample 37).

Claims (4)

1. A binder composition for producing an insulating composite material containing a binder, hydrophobic airgel particles and hollow non-porous particles, characterized in that it further comprises ammonium polyphosphate and a cationic surfactant (CPAS), which is a quaternary ammonium salt - a mixture of alkyl dimethylbenzylammonium chlorides where alkyl is a mixture of normal alkyl radicals, while the surfactant is taken in an amount of 0.1-2 wt. % by weight of an aqueous acrylic binder in the following ratio of ingredients, wt. %: hydrophobic airgel particles and hollow non-porous particles 45 - 55 ammonium polyphosphate 20 - 30 cationic surfactant (CPAS) 8 - 10 water acrylic binder rest 2. The binder composition according to claim 1, characterized in that the surfactant is dimethylcobenzylammonium chloride (MCB-80), a molecular weight of 350, a density of 0.98 g / m ³ , a viscosity of 75 MPa · s. 3. An insulating composite material containing a main insulating layer based on a composition containing airgel particles and hollow non-porous particles, a binder and optionally ammonium polyphosphate and a cationic surfactant (CAS), wherein said insulating layer has a density of at least 157 kg / m ³ and a thermal conductivity of the layer of at least 0.035 W / (m ² K) and an external heat-reflecting layer containing an aqueous acrylic binder, hollow non-porous particles in an amount of not more than 20 vol. %, ammonium polyphosphate and aluminum powder as an agent, reflecting infrared light, while the thermal conductivity of the insulating composite material is not more than 0.060 W / m ² K.

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