Binder for prepregs, prepreg and article made from it

FIELD: production of binders for prepregs for making heavily-loaded articles used in aeronautical engineering and intended for operation under high humidity conditions (tropics, marine climate); automobile manufacture; shipbuilding and other industries.

SUBSTANCE: proposed binder for prepreg contains the following components, parts by mass: epoxy triphenol resin, 40-60;low-molecular epoxy diane resin, 25-35; high-molecular epoxy diane resin, 3-6; dicyanodiamide, 5.5-7.0 and bis-(N,N'-dimethyl carbamide) of diphenyl methane, 0.05-2.0; solvent, 0-90; silicon dioxide, 1-6. Prepreg contains also 30-42 mass-% of epoxy binder and 58-70 mass-% of fibrous filler. Articles are made from prepreg by molding.

EFFECT: increased gelatinization time; improved quality of prepreg; enhanced strength characteristics.

3 tbl, 6 ex

The invention relates to the field of polymeric composite materials (KM) - based epoxy resins and various fibrous fillers and can be used in aeronautical engineering for the production of highly structural products, working in conditions of high humidity (tropical Maritime climate), as well as in the automobile, shipbuilding and other industries.

Known epoxy composition comprising an epoxy resin, the hardener is dicyandiamide and hardener 9, the solvent and alarmedly complex as a modifier. The specified composition impregnated fiberglass with obtaining the prepreg. Next, the resulting prepreg is collected in a bag and carry out the molding with obtaining fiberglass (RF patent No. 2172328).

The disadvantage of fiberglass, obtained on the basis of the specified epoxy compositions are low strength properties.

The closest analogues adopted for the prototype, is the composition to obtain a binder for prepregs, including, parts by weight: apositively resin - 50-60, low-molecular epoxygenase resin - 25-35, high molecular epoxygenase resin - 4-10, dicyandiamide - 3-4, bis-(N,N'-dimethylcarbamyl)difenilmetana - 4-6, solvent - 0-82, as well as a prepreg, in which the binder using the composition, and as a fibrous filler - glass, organic, carbon strings, tapes, fabrics and yarns, and combinations thereof, and the product obtained by molding the specified prepreg (RF patent No. 2176255).

However, middleware prototype has a short gelling time and lack of adaptability that leads to marriage in the manufacture of large thick-walled and raznoformnyh products, and composite materials made from the prepreg of the prototype, have lower strength properties and high enough degree of preservation of their after exposure to operational factors.

The technical task of the invention is to increase the time of gelatinization and the improvement of the efficiency of the binder, increasing the strength characteristics of KM and products from them and enhancing their preservation after exposure to operational factors (high temperature and humidity).

For the technical solution proposed:

Binder for prepregs, including apositively resin, low-molecular epoxygenase resin, high-molecular epoxygenase resin, dicyandiamide, bis-(N,N'-dimethylcarbamyl)difenilmetana and a solvent, characterized in that it further comprises silicon dioxide at the next

the ratio of components, parts by weight:

A prepreg comprising the specified epoxy binder and the fibrous filler in the following ratio, wt.%:

and as the fibrous filler used glass, organic or carbon filament bundles, fabrics, ribbons, and combinations thereof.

The product obtained by molding the specified prepreg. An important criterion for assessing the structural health KM is its deformation resistance, defined, in particular, the glass transition temperature (T_g) binder (polymer matrix). The above T_gthe higher the degree of implementation of uprugoopticheskii properties of the filler in KM at elevated temperatures of operation. In the present invention T_gMasoumeh is 135-160° With, while the prototype is 120-125°C. As is well known, T_gdepends on the degree of crosslinking (density grid) during curing of the binder. Used as a hardener dicyandiamide allows to obtain a tightly crosslinked network structure, which gives the material high strength and heat resistance. But the effect of dicyandiamide significantly activated at temperatures start molding KM - 120-130°C. Use in the prototype latent but very active at temperatures of 120-130°curing system consisting of bis-(N,N'-dimethylcarbamyl)difenilmetana and dicyandiamide in the ratio 5:3, leads to a rapid (avalanche) the course of the curing reaction with a large evolution of heat and formation of irregular mesh structure. This, in turn, leads to obtaining less strong and less heat-resistant polymer matrix, as well as to the risk of overheating thick-walled workpieces curable material from the exothermic effect. In the present invention, a proper selection of the ratio of dicyandiamide and bis-(N,N'-dimethylcarbamyl)difenilmetana, wherein the dicyandiamide plays the role of a hardener, and bis-(N,N'-dimethylcarbamyl)difenilmetana only slightly activates the curing reaction at temperatures from 80°allows to shift the beginning of the curing reaction in the area of higher to those who of erator, to reduce exothermic effect at temperatures of 120-130°With, attaching the binder to the moment of reaching the end temperature molding (180° (C) optimal properties. When molding large-sized thick-walled and raznoformnyh products is of great importance manufacturability binder. In the present invention gelling time of the binder at temperatures molding 120-130°C is from 30 to 110 minutes In this case, the product has time to warm up evenly at the temperature of molding throughout the volume before the beginning of the active phase of the curing reaction, while in the process of curing a more regular structure of the polymer matrix, which, ultimately, allows you to get AWAY with higher and more stable level uprugoopticheskii properties and save them at a high level when exposed to elevated temperatures and humidity. The middleware prototype gelling time is a little longer than 10 min, which in the case of manufacturing a thick-walled products allows you to get AWAY with a fairly stable properties.

The application of the proposed binder of silicon dioxide allows you to optimize the rheological properties of the binder, that is, to increase the viscosity of the binder to the optimal values at the temperature of molding. One of the characteristics of rheological voistlusega is the mass fraction of the fluid resin. This indicator binder prototype 1.5-2 times higher than that of the binder according to the invention. A high proportion of the fluid resin results in spontaneous bleeding binding of the prepreg in the molding process, and therefore KM is obtained with a high content of pores in the structure, which in turn leads to a decrease in the heavily loaded resource of products, particularly in terms of marine and tropical climate. The introduction of silicon dioxide prevents excessive depletion molded package product binder, and also improves and such technological properties of prepregs, such as stickiness, drape, etc. that greatly facilitates the process of manufacturing articles of complex configuration method calculations.

As apositively resin in the present invention use triglycerol ester of 1,1,3-three(oxyphenyl)propane on THE other 2225-316-09201208-94.

As the low molecular weight epoxygenase resin used resin with molm 300-500 brands ED-16, ED-20, ED-22, etc. according to GOST 10587-84, as the high-molecular epoxygenase resin - resin with molm 900-1800 brands of e-40 (GOST 5.1408-72), e-41 (TU 6-10-607-78), e-49 (TU 6-10-606-79) and other

In the examples according to the invention is used dicyandiamide on THE 6-09-3967-80 and bis-(N,N'-dimethylcarbamyl)difenilmetana on THE 6-14-22-159-83.

As of silicon dioxide can be used Aerosil and ELA soot.

As fillers in examples according to the invention were used: example 1 - the roving RUN-N 10-400-14 (TU 6-48-05786904-142-94, in example 2, carbon harness Chis-M-3K (TU 1916-146-05763346-96), example 3 - thread technical SVM-N (TU 2272-018-51605609-2000), in example 4, the glass roving and carbon tow in the ratio of 1:1, in example 5 - fiberglass T-10-80 (GOST 191-70).

A binder according to the invention can be used to produce prepregs as rasplavnoj and mortar technology, using as solvent a mixture of aliphatic alcohol (ethyl, isopropyl) and acetone in their mass ratio of 3:5.

Examples of implementation

Example 1.

In the reactor - mixer with a propeller stirrer download 10 parts by weight of the low molecular weight epoxygenase resin, 50 parts by weight of apositively resin and 6 parts by weight of the high molecular epoxygenase resin and stirred at a temperature of 160-170°C for 3 hours to obtain a homogeneous mass (melt). Later in the mixer load of 5.5 parts by weight of dicyandiamide, and 0.5 parts by weight of bis-(N,N'-dimethylcarbamyl)difenilmetana, 5 parts by weight of white carbon black and 20 parts by weight of the low molecular weight epoxygenase resin in the form of pre-cooked pasta, and then produce the components are mixed for 1.5-2 hours at a temperature of 65-75°C. the Obtained binder can be stored in a tightly closed container for 3 months the EV at room temperature and 6 months - at a temperature of 5-10°C. the Obtained binder in the amount of 30 wt.% impregnate the fibrous filler is glass roving in the amount of 70 wt.% and winding method with the subsequent molding in an autoclave made spar blades of the helicopter.

Technology for producing a binder for examples 2-4 is similar to example 1. Example 5 used the mortar technology for producing binder.

Table 1 shows the compositions of the binder according to the invention and prototype, in table 2 - properties of binders and prepreg in table 3 - types of fillers and properties of KM according to the invention and of the prototype. According to example 2 was manufactured blade motor fan method calculations with subsequent molding in an autoclave, for example 3 - the protective outer shell of the fan motor winding method, followed by curing in an oven, for example 4 - spar blades of the helicopter by winding with a subsequent molding in an autoclave, for example 5 - butt part of the spar the blades of the helicopter method calculations with subsequent molding in an autoclave.

The invention is not limited to the given examples.

As can be seen from the data of tables 2 and 3, the gelling time of the binder is increased from 3 to 10 times, depending on the nature and structure of the filler, the strength characteristics of the KM increased by an average of 12-15%, the level of conservation of properties pravoslavie elevated temperatures rose to 92-98%, water absorption decreased on average by 20%.

Thus, the proposed junction has reduced in comparison with the prototype reactivity and optimized rheological properties in the curing process, so as to avoid defects in the manufacture of large thick-walled and raznoformnyh products, such as spars blades of helicopters, etc. Increased the glass transition temperature of the polymer matrix in KM has a positive effect on the operating characteristics of KM, such as water and moisture resistance, fatigue and creep rupture strength, creep, that allows to increase the reliability and service life of products.

1. Binder for prepregs, including apositively resin, low-molecular epoxygenase resin, high-molecular epoxygenase resin, dicyandiamide, bis-(N,N'-dimethylcarbamyl)difenilmetana and a solvent, characterized in that it additionally contains silicon dioxide in the following ratio of components, parts by weight:

2. A prepreg comprising an epoxy binder and a fibrous filler, wherein the binder using a binder according to claim 1 in the following ratio, wt.%:

3. The prepreg according to claim 2, characterized in that as the fibrous filler used glass, organic or carbon filament bundles, fabrics, ribbons, and combinations thereof.

4. The product, characterized in that it is made by molding the prepreg according to claim 2.