RU2302431C1 - Method of production of the prepreg - Google Patents

Abstract

FIELD: chemical industry; aerospace industry; shipbuilding industry; other industries; methods of production of prepreg.

SUBSTANCE: the invention is pertaining to the method of production of the prepreg used at manufacture of the polymeric composite materials for aerospace, ship-building and other industries, requiring materials with the improved fire-fighting properties. The method includes impregnation of the fibrous roll long-sized material with the thermoreactive binding, excision of the excesses of the thermoreactive binding by gating of the impregnated fibrous roll long-sized material through the squeeze rollers with the subsequent drying. Before drying on the impregnated with the binding fibrous roll long-sized material they apply the layer of the powdery fire-retardant agent from 20 mass % up to 50 mass % of the gross weight of the thermoreactive binding and the powdery fire-retardant agent. Then the material additionally is gating through the stitch rollers with the adjustable force of the pressure. At that the force of the pressure is set such that after the stitching on the material there should stay the layer of the non-rolled powdery fire-retardant agent of no less than 10 mass % of the applied layer with the subsequent excision of the non-rolled powdery fire-retardant agent. As the powdery fire-retardant agent use the hydroxide of a metal. The invention allows to produce the prepreg with the high fire-fighting properties.

EFFECT: the invention ensures production of the prepreg with the high fire-fighting properties.

5 tbl, 3 ex

Description

The invention relates to the field of producing a prepreg by impregnating fibrous rolled lengthy materials with liquid, including melt materials and can be used in the manufacture of polymer composite materials for aerospace, shipbuilding and other industries requiring materials with improved fire properties.

Known methods for impregnating a rolled long material, including impregnating a sheet substrate with a polymer material, removing excess polymer material using squeeze rolls, and subsequent drying (A.S. USSR No. 579032, No. 628195, Japanese application No. 63-36921).

A known method of producing a prepreg, comprising impregnating the polymer material with a binder, applying a layered coating to its surface, the top coating layer being anti-adhesive, folding the prepreg into a roll and subsequent drying (US application No. 200491622).

The disadvantages of the known methods are the inability to ensure the impregnation of the sheet substrate with liquid polymer material mixed with the powder material due to the sticking of the powder on the squeeze rolls and, therefore, the inability to ensure high fire-fighting properties of the polymer composite material made from such a prepreg.

The closest adopted for the prototype is a method for producing a prepreg, comprising impregnating a fibrous roll of lengthy material with a thermosetting binder, removing excess thermosetting binder by passing the impregnated fibrous roll of lengthy material through spinning rolls, followed by drying of the prepreg (Japanese Application No. 59133016).

The known method does not allow to obtain a fireproof prepreg with a uniform distribution of components due to the sticking of the powder on the squeeze rolls while removing excess impregnating mixture; due to the rapid depletion of the mixture, i.e. reducing the percentage of the liquid component due to its greater, compared with the powder, ability to pass into the fiber and soak it.

The technical task of the invention is the creation of a method that allows to obtain a prepreg with high fire properties.

To solve the technical problem, a method for producing a prepreg is proposed, including impregnating a fibrous roll of lengthy material with a thermosetting binder, removing excess thermosetting binder by passing the impregnated fibrous roll of lengthy material through squeeze rolls, followed by drying, characterized in that before drying, the impregnated fibrous roll of lengthy material is applied a layer of powder flame retardant from 20 wt.% to 50 wt.% of the total weight of the thermosetting binder and a particulate flame retardant, and further passed through the stitching rollers with adjustable clamping force, the pressing force is adjusted so that, after the stitching on a material layer remained neprikatannogo retardant powder is not less than 10 wt.% of the damage, followed by removal neprikatannogo retardant powder.

Metal hydroxide is used as a powder flame retardant.

The theoretical justification of the proposed method is that the impregnated fibrous rolled lengthy material with a layer of powder flame retardant deposited on it additionally passes between the press rolls, which, passing the material with a layer of powder flame retardant with a certain pressure, push the powder flame retardant into the impregnating material of the thermosetting binder moreover, the amount of pressed powder flame retardant depends on the clamping force. In order to reliably prevent the sticking of powder flame retardant on the stocking rolls, the clamping force is set so that part of the powder flame retardant remains non-rolled, i.e. not pressed into a thermosetting binder. This portion of the flame retardant powder is subsequently removed. The exclusion of the sticking of the thermosetting binder in the mixture with the powder flame retardant particles pressed into it allows maintaining the obtained high degree of uniformity of the content of the liquid and powder components in the prepreg, which, in turn, improves the fire-fighting properties of the polymer composite material obtained from such a prepreg.

In the process of experimental work, it was found that a decrease in the layer of non-rolled powder flame retardant of less than 10 wt.% Of the applied leads to an increase in its adhesion to the stock rolls. A larger amount of non-rolled powder flame retardant does not affect its sticking to the stock rolls and only leads to an excessive consumption of powder flame retardant and an increase in the cost of its removal for subsequent return to production.

Also, in the course of experimental work, it was found that the application of a powder flame retardant on a substrate of less than 20 wt.% Of the total weight of the thermosetting binder and powder flame retardant leads to the release of heat values beyond the requirements of Aviation Rules AP-25, both in terms of the maximum heat release rate and the total amount of heat released in 2 minutes. Therefore, to solve the technical problem of the invention, it is advisable to apply powder fire retardant in an amount of from 20 wt.% To 50 wt.% Of the total weight of the thermosetting binder and powder flame retardant on the fibrous rolled lengthy material.

An example implementation.

The method of obtaining the prepreg was tested in semi-industrial conditions on the installation for the impregnation of fibrous rolled lengthy materials UPP. As a rolled lengthy material used fiberglass T-15P-76 (TU 6-48-107-94). As a thermosetting binder, thermosetting binders FPR-520 (TU-595-25-436-93), UP-2227 (TU 1-595-12-526-98), ENFB-2M (TU 1-595-25-494) were used. -96). The powder of flame retardant was aluminum hydroxide powder Al (OH) ₃ , magnesium Mg (OH) ₂ , and titanium Ti (OH) ₄ .

To fill the powder flame retardant, a hopper mounted on top of the fiberglass was used with a long slit, the axis of which was located at an angle to the moving fiberglass. Induction coils with iron cores were located on the body of the bunker. When the coils were connected to an electric current, the cores began to knock on the bunker body, creating a vibration, with the help of which the powder flame retardant was spilled onto the moving fiberglass.

A fiberglass roll T-15P-76, dipped in a thermosetting binder FPR-520, located in the bath, and impregnated with it. After impregnation, the fabric was passed through squeeze rolls to remove excess thermoset binder. Then, flame retardant powder was poured onto the impregnated fiberglass fabric in an amount of 20 wt.% Of the total weight of the thermosetting binder and powder flame retardant and passed through the rolls with effort, so that after rolling, a layer of non-welded powder flame retardant remained at least 10 wt.% from applied. After this, the prepreg passed through the heating and cooling units, where, in the latter, by blowing with compressed gas, excess powder flame retardant was removed and wound into a roll.

Table 1 shows the uniformity of the application of thermosetting binder and powder flame retardant to fiberglass. As can be seen, in the proposed method, the uneven deposition along the length of the roll is in the range +/- 1-1.2%.

Table 2 shows the experimental data on the content of powder flame retardant in the prepreg, depending on the clamping force of the rolls. The initial content of the powder flame retardant is not less than 20 wt.% And not more than 50 wt.% Of the total weight of the thermosetting binder and powder flame retardant.

As can be seen from the above data, an increase in the clamping force by a factor of 6 leads to an increase in the content of powder flame retardant in the prepreg by about 1.5 times, i.e. from 32 wt.% to 55 wt.%.%. Excess powder flame retardant (remaining unpacked) was removed by blowing with compressed gas.

Table 3 provides data on the uniformity of the content of thermosetting binder and powder flame retardant depending on the non-rolled residue of the powder flame retardant.

As can be seen from table 3, the non-uniformity of the application of thermosetting binder and powder flame retardant is very significant and has a nonrandom character, when the non-rolled powder flame retardant residue is 8% of the total amount of applied flame retardant, i.e. due to the adherence of the powder to the squeeze rolls, a sharp decrease in the content of the binder and flame retardant on the impregnated material is observed. With a non-rolled residue of 10% and 12%, the unevenness of application is negligible. The amount of non-rolled powder flame retardant was determined by the weight method by weighing the non-rolled powder collected.

Tables 4 and 5 give data on the fire-fighting properties of PCM obtained from a prepreg made by the proposed method (example 1-3) and the prototype method (example 4). Polymer composite material (PCM) is made of several layers by vacuum molding. The time of burnout of the material by a flame with a temperature of 927 ° С + 38 ° was determined according to Aviation Rules AP-25.

As can be seen from table 4, the maximum heat release rate in examples 1-3 is significantly less than the standards established by AP-25, in example 4, the maximum heat release rate significantly exceeds the limit standards.

Flammability tests conducted in accordance with AP-25 (exposure time 60 s) also showed high fire-fighting properties of fiberglass made from prepreg according to the proposed method.

In all samples according to examples 1-3, the residual burning time and burn-out length are less than the norms established by the Aviation Rules AP-25. Fiberglass, obtained from the prepreg by the prototype method, significantly exceeds the maximum allowable standards for combustibility.

Thus, the application of the proposed method allows to obtain a prepreg with high fire properties, which are ensured by a high degree of uniformity of distribution of the liquid and powder components in the prepreg. A polymer composite material made from such a prepreg will have improved reliability and safety characteristics compared to the specified analogues and prototype.

Table 1 Sample number Start of roll% The middle of the roll% End of roll% Sample No. 1 FPR-520 + AL (OH) ₃ in the ratio of 50 wt.% + 50 wt.% 36.6 38 37,2 Sample No. 2 UP-2227 + Mg (OH) ₂ in the ratio of 65 wt.% + 35 wt.% 35,4 37.8 37.5 Sample No. 3 ENFB-2M + Ti (OH) ₄ in the ratio of 80 wt.% + 20 wt.% 37.7 37.7 38.5 table 2 Clamp force kg / cm ² Start of roll% The middle of the roll% End of roll% 0.10 33 34 32 0.2 36 35 35 0.4 41 40 41 0.6 55 53 55 Table 3 No. of sample and the amount of flame retardant remaining unpacked (wt.%) Start of roll% The middle of the roll% End of roll% No. 1-8% 40,0 30,0 14.5 No. 2-10% 36.0 36.7 36,4 No. 3-12% 36.8 36,2 36.8

Table 4 Description of samples Number of layers Thickness mm Maximum heat dissipation rate kW / m ² The total amount of heat generated in 2 min kW · min / m ² Fiberglass: fiberglass T15P76 + FPR-520 + AL (OH) ₃ in the ratio of 50 wt.% + 50 wt.% four
8
12 1.15
2,36
3.48 36
47
19 fifteen
<5
> 5 Fiberglass: fiberglass + UP-2227 + Mg (OH) ₂ in the ratio of 65 wt.% + 35 wt.% four
8
12 1.10
2.17
3.34 44
53
34 thirty
10
<5 Fiberglass: fiberglass + ENFB-2M + Ti (OH) ₄ in the ratio of 80 wt.% + 20 wt.% four
8
12 1,0
2.08
3.25 55
60
52 60
fifty
25 Fiberglass: fiberglass + FPR-520 obtained by the prototype method 8 2.0 120 90

Table 5 Description of samples Number of layers Thickness mm Residual burning time, s Burnout length m Classification Fiberglass: fiberglass T15P76 +
FPR520 + AL (OH) ₃ in the ratio of 50 wt.% + 50 wt.% four
8
12 1.15
2,36
3.48 2
one
0 37
28
17 Hard to burn Fiberglass: fiberglass T15P 76 + UP-2227 + Mg (OH) ₂ in the ratio of 65 wt.% + 35 wt.% four
8
12 1.10
2.17
3.34 5
3
0 62
45
21 Hard to burn Fiberglass: glass fabric T15P 76 + ENFB-2M + Ti (OH) ₄ in the ratio of 80 wt.% + 20 wt.% four
8
12 1,0
2.08
3.25 6
four
2 70
66
41 Hard to burn Fiberglass: fiberglass T15P76 + FPR-520, obtained by the prototype method 8 2.0 eighteen 95 self extinguishing

Claims (2)

1. A method of producing a prepreg, including the impregnation of a fibrous roll of lengthy material with a thermosetting binder, removing excess thermosetting binder by passing the impregnated fibrous roll of lengthy material through squeeze rolls, followed by drying, characterized in that before drying the impregnated fibrous roll of lengthy material is coated with a powder of flame retardant 20 to 50 wt.% Of the total weight of the thermosetting binder and powder flame retardant and additionally pass black without pressurizing rolls with an adjustable clamping force, and the clamping force is set so that after rolling, a layer of non-rolled powder flame retardant remains at least 10% of the applied, followed by removal of the non-rolled powder flame retardant. 2. The method according to claim 1, characterized in that the metal hydroxide is used as a powder flame retardant.