RU2764442C1 - Polymer composition for the production of high-strength, thermo- and fire-resistant syntactic foams - Google Patents

Abstract

FIELD: polymers.

SUBSTANCE: present invention relates to a polymer composition for the production of high-strength, thermo- and fire-resistant syntactic foams. This composition is a polymer composition based on epoxy resins with increased specific functionality, nitrogen-containing hardeners and hollow microspheres with a diameter of 10 to 500 microns. The epoxy component is a mixture obtained by mixing epoxy resin and vinyl cyclohexene monoxide in a reactor. The hardener is a mixture of an amino adduct of para-aminobenzylaniline with an epoxy resin-diglycidyl ether of poly epichlorohydrin obtained by the interaction of epoxy resin with amine, and 4,4'-diphenylmethanediisocyanate blocked by methylpyrazole. The amount of hardener is from 40 to 80 pts. wt. % per 100 pts. wt. %, of the epoxy component. Polymer base: microspheres ratio ranges from 90:10 to 50:50 pts. wt. %.

EFFECT: polymer composition makes it possible to obtain high-strength, thermo- and fire-resistant syntactic foams without ignition when curing samples filled with hollow microspheres up to 400 mm thick.

1 cl, 2 tbl, 4 ex

Description

The invention relates to the field of obtaining high-strength, heat- and fire-resistant syntactic foam plastics - spheroplastics, resistant to long-term solar radiation.

Known polymer composition, patent No. 2226202 publ. 03/27/2004, bul. No. 9. The invention relates to polymer products used for the manufacture of protective coatings for building structures, pipelines for the purpose of their thermal insulation and complex insulation. Heat-insulating composition with a density of 51-75 kg/m ³ based on rigid polyurethane foam containing 70-95 wt. % polyurethane and 5-30 wt. % glass microspheres. Fractions of glass microspheres with a size of 30-50 microns, 60-140 microns, as well as mixtures of these fractions are used.

The disadvantage of the composition is insufficient light fastness.

Known polymer composition, patent No. 2220990 publ. 01/10/2004, bul. №27 Invention relates to self-extinguishing polymer compositions with filler in the form of hollow microspheres, which serve to fill sections of honeycomb structures used in aviation technology. The polymer composition includes, parts: epoxy resin 32-35, oligoamidoamine 20-23, hollow glass microspheres 26-30, ammonium phosphate 16-18 and powder of cured phenol-formaldehyde resin 5-15.

The disadvantages of the known compositions is that they have insufficiently high compressive strength.

A composition using epoxy compounds and hollow microspheres is known, which, according to the authors, makes it possible to obtain high-strength spheroplastics (patent RU 2540084, publ. 27.01.2015, bull. No. 3, prototype). This patent provides polymer compositions based on cycloaliphatic epoxy resins UP-612, UP-632 and UP-639, called oligomers by the authors of the prototype, although in fact they are at least 99% monomeric dioxides, traditionally referred to in the industry as resins. The disadvantages of the mentioned compositions are the low strength properties of polymers based on them and poor adhesion to glass fibers and microspheres, tk. they are olefin dioxides. The most important strength indicators - tensile and static bending strength - of cured resins UP-612 and UP-632 are 2–3 times lower than those of polymers based on the most common resins ED-20 and ED-16 (Handbook of plastics / ed. V. M. Kataeva, V. A. Popova, B. I. Sazhina, Moscow: Chemistry, 1975, vol. 2, 567 p.). In addition, polymers based on cycloaliphatic resins UP-632 and others are combustible, like all paraffins or cycloparaffins (their coke number is zero, while for polymers based on resins of the ED-20 type it is 35%, and for non-combustible phenol-formaldehyde polymers - 55%).

It is known that the highest strength characteristics in combination with increased heat resistance of cast samples of polymers and glass-filled materials are achieved using compositions based on epoxidized aromatic and heterocyclic amines. These are resins such as UP-610, EHD and ETs. Moreover, the latter composition, containing a triazine cycle and being an analogue of melamine-formaldehyde resins in terms of the structure of the cycle, is resistant to flame, solar radiation, and corona discharges. However, due to the high activity of these resins in the process of curing with any serial hardeners (due to the catalytic action of tertiary nitrogen included in their structure and an increased content - 30 ÷ 40% - of epoxy groups), they spontaneously ignite due to the strong release of exothermic heat in cast samples with a thickness of 30 ÷ 50 mm, which is exacerbated by the introduction of heat-insulating hollow microspheres.

The purpose of the claimed invention is a polymer composition that makes it possible to obtain high-strength, heat- and fire-resistant spheroplasts without ignition during curing of specimens up to 400 mm thick filled with hollow microspheres.

The technical problem posed is solved by using a nitrogen-containing resin - triglycidyl isocyanurate brand ETs-N (TU 6-05-1190-76), widely used in the form of a solution in the manufacture of pre-impregnated glass fabrics, tapes and heat-resistant composites based on them since the times of the USSR. It is known that samples based on EC-N of small thickness have high strength and heat resistance up to +300°C. However, this resin in the initial state is a highly viscous product and does not allow one to obtain filled spheroplasts of large thicknesses, because when cured in a layer with a thickness of 30÷50 mm, it ignites when heated to +100°C even without a hardener due to the catalytic action of tertiary nitrogen in its structure.

The authors managed to overcome the shortcomings of the ETs-N resin by diluting it with vinylcyclohexene monoxide (CAS 100-40-3), an epoxy compound with the lowest viscosity at +20°C among all known epoxides, equal to 0.001 Pa⋅s, and also by using dual hardener systems that cure epoxy resins at different temperatures. This system consists of a liquid amino adduct of para-aminobenzylaniline - the result of the interaction of the latter with polyepichlorohydrin diglycidyl ether (technical name resin E-181, TU 2225-606-11131395-2003), first obtained by Lapitsky V.A. with employees, and the second component in the system of hardeners - 4,4'-diphenylmethane diisocyanate blocked with methylpyrazole, previously synthesized and patented in the USSR with the participation of one of the authors of this patent, and later described in the monograph by Lapitsky V.A. and Kritsuka A.A. "Physical and mechanical properties of epoxy polymers and fiberglass" (Kiev: Naukova Dumka, 1986. - 96 p.).

The first component begins to cure the resin part, starting from a temperature of +50°C, and the second one remains inert until unlocking at a temperature of 150÷170°C. Therefore, curing occurs in two stages with an acceptable release of exothermic heat and makes it possible to obtain highly filled spheroplastics up to 400 mm thick in one step.

Example 1

1. Getting the resin part

Epoxy resin brand ETs-N (TU 6-05-1190-76) (A) and vinylcyclohexene monoxide (CAS 100-40-3) (B) are loaded into a reactor with a high-speed stirrer in a ratio of 70:30 and at +50°C mixed for 20 minutes, after which they are unloaded into metal containers. Shelf life - 2 months.

2. Obtaining a curing system

In a reactor with a high-speed stirrer load 23 wt.h. para-aminobenzylaniline brand "Benzam ABA" (TU 2225-415-04872688-99) and raise the temperature to +90°C, and then pour the epoxy resin E-181 (TU 2225-606-11131395-2003, content epoxy groups 30%) in the amount of 10 wt. hours, i.e. with a fivefold excess of hardener from the stoichiometric amount for epoxy resin. The result is component (B). The reaction is exothermic, so the reactor must be constantly cooled. After introducing the resin to the hardener, the reaction mass is stirred for 20 minutes, and then powder of blocked isocyanate (G) is added to it in an amount of 22 wt. hours, i.e. ratio W:D=60:40, and stirred for 5 minutes. The finished product is poured into metal containers. Shelf life - 3 months.

3. Obtaining spheroplast

100 wt. including the resin part and 60 wt. hours of hardener obtained in the two previous stages, and then at a temperature of the loaded mass of +40 ° C, hollow aluminosilicate microspheres of the ASPM-500 brand with a diameter of 10 to 500 microns (TU 5717-001-11843486-2004) are introduced in a weight ratio polymer base: microspheres, equal to 70:30. The mixture is evacuated for 10 minutes, and then unloaded into restrictive metal molds and cured in two stages, the first at +70°C for 4 hours, the second at +160°C for 2 hours.

The polymer base has a high adhesive capacity, therefore, in the manufacture of samples, restrictive metal molds are coated with an anti-adhesive agent, and in the manufacture of structures coated with the resulting spheroplast, no additional glue is required.

Examples 2÷4 are carried out similarly to example 1 with a change in individual parameters according to table 1.

Claims (1)

Polymer composition for obtaining high-strength, heat- and fire-resistant spheroplasts based on epoxy resins with increased specific functionality, nitrogen-containing hardeners and hollow microspheres with a diameter of 10 to 500 μm, characterized in that the mixture obtained by mixing epoxycyanurate resin in a reactor is used as an epoxy component (A) and vinylcyclohexene monoxide (B) in the ratio A:B (wt. h.) from 80:20 to 60:40, and as a hardener - a mixture of amino adduct of para-aminobenzylaniline with epoxy resin - diglycidyl ether of polyepichlorohydrin obtained in the interaction of epoxy resin with amine at a 4÷6-fold excess of the latter from the stoichiometric amount for epoxy resin, (C) and 4,4'-diphenylmethane diisocyanate blocked with methylpyrazole, (D) in the ratio V:D (wt. h.) from 80:20 to 60:40, while 100 wt. including the epoxy component, the hardener is introduced in an amount of 40 to 80 wt. hours, and hollow microspheres are introduced in the ratio polymer base: microspheres (wt. h.) from 90:10 to 50:50.