WO2019112460A1 - Composition for impregnating reinforcing material and method for producing same - Google Patents

Abstract

The group of inventions relates to binders for polymeric composite materials, more particularly for materials for outer space applications, and to methods for producing same. Proposed is a method for producing a composition of melt binders based on metal chelates and oligocyanurate resins with reactive cyanate groups for impregnating reinforcing material in polymer composite materials for outer space applications, wherein a resin is heated to a molten state, a catalyst, consisting of metal chelates in the form of dry powder with a particle size of 40-125 µm, is introduced into the melt produced, the amount of catalyst added being 50-600 ppm based on the ratio of metal ion mass to the total weight of the composition, and the melt is then mixed to a visually uniform state. The composition for impregnating reinforcing material in polymer composite materials for outer space applications produced by the proposed method is in the form of a solution or melt comprising 50-600 ppm of complex compounds or mixtures thereof comprising ions of aluminium, transition metals and rare-earth elements with various organic ligands in resins having reactive cyanate groups, and is solvent- or diluent-free.

Description

 COMPOSITION FOR IMPREGNATION OF REINFORCING MATERIAL AND

 METHOD OF OBTAINING IT

TECHNICAL FIELD

 The group of inventions relates to a binder for polymer composite materials, in particular for materials for space purposes, and to methods for their preparation.

 BACKGROUND

 In the manufacture of polymer composite materials for space applications, three types of thermosetting binders are mainly used: epoxy, bismaleimide, and polycyanurate. Polycyanurate binders differ from epoxy and bismaleimide binders, first of all, by increased crack resistance during thermal cycling, reduced moisture absorption, high resistance to cosmic radiation, and better dielectric characteristics; therefore, they are most suitable for manufacturing dimensionally stable structures for space purposes.

 Known compositions based on aromatic or perfluoroaliphatic dicyanates and metal chelates (patent US 3694410). These compositions make it possible to obtain polymers with different physicomechanical properties and at different curing temperatures, depending on the amount and type of metal chelate used. The disadvantage of these compositions is that organic solvents, such as methylene chloride or chloroform, are used to obtain them, which leads to residual solvents in the binder and, as a consequence, the formation of pores in the molding process, which reduces the physicomechanical characteristics of composite materials.

Known compositions based on aromatic dicyanates and liquid solutions of metal acetylacetonates in high-boiling alkyl phenols (patent US 4847233A). These compositions also allow to obtain polymers with different physicomechanical properties and at different curing temperatures, depending on the amount and type of metal chelate used, moreover, the absence of a low-boiling solvent solves the problem of increased pore formation during the molding of products. The disadvantage of these compositions is that a large amount of alkylphenol is used to obtain them (10 or more times the amount of metal acetylacetonate), which is partially chemically bound to the polymer, forming thermally unstable hydrophilic imidocarbonate structures that promote increased moisture absorption and gas evolution at elevated temperatures . Chemically unbound alkylphenol under conditions of high vacuum when the product is in open space can diffuse outward, leaving behind micropores, which will lead to a change in the geometry of the precision dimensionally stable design. In addition, the alkylphenol particles diffusing to the outside can settle due to electrostatic interaction on sensitive instruments of the spacecraft, for example, optics, which can lead to loss of device performance.

 The closest known are compositions based on aromatic dicyanates with nanoscale (average particle size from 1 to 100 nm) filler - zinc oxide in the amount of 0.001-1 weight fractions without the use of solvents and diluents (patent JP 2006-328177). These compositions have a low dependence of catalyst activity on temperature and slightly increase the viscosity of the binder after the introduction of the catalyst.

 The disadvantage of these compositions is that curing temperatures are required for their polymerization, well above 120-125 ° C, which limits their use and complicates the process of manufacturing polymer composite materials. In addition, zinc oxide is insoluble in melts of aromatic dicyanates, this complicates the process of dispersion and control of the uniform distribution of the catalyst.

 SUMMARY OF INVENTION

 A common task addressed by the group of inventions, and a common technical result achieved using a group of inventions, is the development of a polycyanurate binder with a minimum curing temperature not higher than 125 ° C, which eliminates the use of solvents and / or diluents and reduces the gas evolution of composite materials in products space destination.

The task and the required technical result is achieved due to the new method of obtaining the composition of melt binders based on metal chelates and oligocyanurate resins with active cyanate groups for impregnation of reinforcing material in polymer composite materials for space purposes, in which the resin is heated to melt state, the catalyst is introduced into the resulting melt in the form of a dry powder of metal chelates with a particle size of 40-125 microns in an amount of 50- 600 ppm in the ratio of the mass of metal ions to the mass of the composition and mix the melt to a visually homogeneous state.

 The task and the required technical result is also achieved due to the new composition for impregnating reinforcing material in polymer composite materials for space, obtained by the proposed method, in the form of a solution or melt 50-600 ppm of complex compounds or their mixtures of aluminum ions, transition metals and rare earth elements, with various organic ligands in resins with active cyanate groups, without using any solvents or diluents.

 DISCLOSURE OF INVENTION

According to the invention, the composition is a solution or melt of complex compounds or their mixtures of aluminum ions, transition metals and rare earth elements, with various organic ligands in resins with active cyanate groups, without using any solvents or diluents. The proposed composition (binder) includes monomers with active cyanate groups or oligomers with active cyanate groups or their mixtures, contains 50-600 million parts (in terms of the mass of metal ions to the composition) of the dissolved catalyst and does not contain solvents or active diluents. As catalysts, for example, coordination-saturated complex compounds or their mixtures can be used, in which metal ions are used as complexing agents, and acetylacetonate ions and / or neutral molecules capable of binding to complexing agent, for example, 1, 10 are used as ligand. -fenantrolin, 2,2 ^'-bipiridin or triphenylphosphine oxide.

The binder may also contain various additional components: various polymers, resins, fillers, dyes, pigments, thickeners, lubricants or flame retardants acting as modifiers a binder, and not being solvents or diluents of the metal complex catalyst.

 According to the invention, the method of obtaining the composition (binder) consists in the fact that at first the catalyst is crushed to a particle size of preferably 40-125 μm and only after that is introduced into the resin. This method allows to obtain a homogeneous solution (melt) of the catalyst in the resin (as opposed to the patent US 4847233A) without using any solvents or diluents. To achieve the result, the particle size may be somewhat outside the specified range, however, the use of particles smaller than 40 microns leads to a significant electrification of particles and makes sowing difficult, and the use of particles larger than 125 microns increases the mixing time or does not allow to achieve homogeneity of the melt.

 The present invention is illustrated by the following examples.

 Examples of comparison.

A resin (3 samples of 20 g each) based on bisphenol A dicyanate oligomerized at 170–200 ° C (viscosity of 1.5 Pa ^* s at 80 ° C) is taken and heated to melt state at 80 ° C. Next, the catalyst is introduced into the melt. In the first case (obr.1) in the form of a dry powder of copper acetylacetonate with a particle size of not more than 100 microns in an amount of 300 ppm - 0.0247 g. In the second case (obr.2) in the form of a solution 200 ppm - 0.0655 g of acetylacetonate copper in 0,400 g of nonylphenol. In the third case (obr.z) in the form of a solution of 150 ppm - 0.0124 g of copper acetylacetonate in 0.400 g of nonylphenol. After the introduction of the catalyst, the melts are well stirred until homogeneous (the homogeneity of the composition is established visually by the formation of a transparent melt colored in the color of the corresponding catalyst).

Part of the prepared compositions, 10 g each, is poured into molds and cured at 125 ° C for 10 hours, the glass transition temperature of the obtained samples is measured. The remaining parts of the prepared compositions are maintained at 80 ° C, periodically measuring the viscosity. The results of viscosity measurements are shown in the table.

 The larger the catalyst, the shorter the time it takes to bind a viscous state and the higher the glass transition temperature after curing. Based on the data obtained, it can be seen that the lifetime depends on both the amount of the introduced catalyst and the presence of nonylphenol (sample 2 is given as an example to confirm this conclusion). Examples of comparison should be considered arr. 1 and arr. 3, as samples with approximately the same time to maintain a viscous state. The glass transition temperature of these samples turned out to be the same according to DSC data - 135-140 ° C. This suggests that the compositions obtained in the absence of a diluent are not inferior in the glass transition temperature to compositions obtained using a diluent, provided that they have the same lifetime. The advantage of the present invention (for example, Obr.1) is the absence in the composition of solvents and diluents, which reduces the porosity and moisture absorption of products made of composite materials.

 Example 1

The oligocyanurate resin (30 g) based on bisphenol M dicyanate is heated to 50 ° C (melt viscosity at a given temperature of 0.5 Pa * s). Next, a catalyst (300 ppm Zn) —0.0636 g of powder of phenanthrolinate zinc acetylacetonate (Zn (acac) 2phen) with a particle size of not more than 100 μm is introduced into the melt and the melt is well mixed at 50 ° С to a homogeneous state (a transparent mass of light orange). The resulting composition is poured into a mold and cured at 125 ° C for 10 hours. The obtained plastic sample after cooling has a glass transition temperature in the region of 103-108 ° C (according to DSC data). The gelation time of this composition is more than 20 hours at 50 ° C.

 Example 2

 The oligocyanurate resin (30 g) based on bisphenol A dicyanate is heated to 80 ° C (the melt viscosity at this temperature is 1, 5 Pa * s). Next, a catalyst is injected into the melt (50 ppm Fe) - 0.0094 g of iron acetylacetonate powder (Fe (ac) h) with a particle size of not more than 40 μm and the melt is well mixed at 80 ° C to a homogeneous state (a transparent mass of dark red is formed colors). The resulting composition is poured into a mold and cured at 125 ° C for 10 hours. The obtained plastic sample after cooling has a glass transition temperature of 133-138 ° C (according to DSC). The gelation time of this composition is about 3 hours at 80 ° C.

 Example 3

 The oligocyanurate resin (30 g) based on bisphenol A dicyanate is heated to 80 ° C (the melt viscosity at this temperature is 1, 5 Pa * s). Next, a catalyst (300 ppm Zr) —0.0636 g of zirconium acetylacetonate powder (Zr (acac) 4) with a particle size of not more than 125 μm is introduced into the melt and the melt is well mixed at 80 ° C to a homogeneous state (a transparent yellow mass is formed) . The resulting composition is poured into a mold and cured at 125 ° C for 10 hours. The obtained plastic sample after cooling has a glass transition temperature of 125-130 ° C (according to DSC). The gelation time of this composition is about 8 hours at 80 ° C.

 Example 4

The oligocyanurate resin (30 g) based on bisphenol E dicyanate is heated to 40 ° C (melt viscosity at a given temperature of 0.3 Pa ^* s). Then, a catalyst (600 ppm Tm) —0.0690 g of thulium acetylacetonate phenanthrolinate powder (Tm (acac) 3phen) with a particle size of not more than 100 μm is introduced into the melt and the melt is well mixed at 40 ° C until homogeneous yellow color). The resulting composition is poured into a mold and cured at 125 ° C for 10 hours. The obtained plastic sample after cooling has a glass transition temperature in the region of 150-155 ° C (according to DSC data). The gelation time of this composition is more than 20 hours at 40 ° C.

Claims

CLAIM  1. The method of obtaining the composition of melt binders based on metal chelates and oligocyanurate resins with active cyanate groups for impregnation of a reinforcing material in polymer composite materials for space purposes, in which:  heat the resin to melt;  catalyst is introduced into the melt obtained in the form of a dry powder of metal chelates with a particle size of 40-125 μm in an amount of 50-600 ppm in relation to the weight of metal ions to the weight of the composition; and  mix the melt to a visually homogeneous state.  2. Composition for impregnation of reinforcing material in polymer composite materials for space purposes, obtained by the method according to claim 1, in the form of a solution or melt 50-600 ppm of complex compounds or their mixtures of aluminum ions, transition metals and rare earth elements, with organic ligands resins with active cyanate groups, without using any solvents or thinners.