CN110001092A - A kind of phenolic resin preimpregnation material and metalwork integral formation method - Google Patents

Abstract

The invention relates to a method for integrally forming a phenolic resin prepreg and a metal part. It includes: (1) the steps of pretreatment of metal parts: sandblasting the profile surface to be bonded to the metal piece, and then applying glue on the metal profile surface; (2) after the process of step (1) The steps of compounding the transition layer on the surface; (3) the step of laying up the phenolic resin prepreg: painting the phenolic resin adhesive on the profile surface compounded with the transition layer, and then applying the phenolic resin prepreg according to the design. The phenolic resin adhesive comprises 100 parts by weight of phenolic resin, 100-120 parts by weight of carboxyl-terminated nitrile rubber, and 0.5-1 part by weight of dispersant; (4) the step of curing. The method overcomes the deficiencies of the existing molding technology, provides a method that can ensure the integral molding of complex profile structural parts, and solves the problem of interface debonding after the composite material and the metal cabin are integrally formed.

Description

A kind of integral molding method of phenolic resin prepreg and metal parts

technical field

The invention relates to the technical field of component molding, in particular to a method for integral molding of a phenolic resin prepreg and a metal part.

Background technique

With the development of aerospace technology, space has become the "commanding heights" for safeguarding national security and interests, and various countries are paying more and more attention to the development of aircraft. Heat protection is one of the most critical factors that determine the safety of aircraft and the smooth completion of various tasks, and ablation heat protection has always been popular for its simple and reliable features, so it has always been the concern of space agencies and experts in various countries. Focus.

At this stage, with various technical requirements getting higher and higher, the product surface is more and more complex, and the wall thickness difference is getting bigger and bigger. According to the traditional molding method, a large margin should be left when molding the complex surface protection, and then the outer protection layer is obtained by machine addition, and finally it is bonded to the metal cabin. In this way, the production process of external protection products for parts is not only long, but also complicated and cumbersome to process. After parts-level bonding, there will be splicing gaps on the surface of the product, and there are risks in use. Therefore, the integrated integrally formed complex profile structure has become the trend of product design. The integrally formed structural member can not only improve the integrity and reliability of the product, but also simplify the production process and improve the production efficiency.

Due to the nature of cross-linking and curing of phenolic molecular chains, the high shrinkage rate of polycondensation curing is caused. Therefore, when composite materials are integrally formed on the cabin, problems such as debonding from the metal interface are often caused due to the mismatch of linear expansion coefficients. In order to solve the problem of debonding in engineering, people often use 9621 rubber film or other epoxy adhesives as a strain isolation layer to solve such problems, but because of the introduction of new materials, the bonding interface will increase, and the aircraft ( The specific shape of the cabin) will inevitably cause local stress concentration areas, so local debonding will still occur.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is: to overcome the deficiencies of the existing molding technology, to provide an integrated molding that can ensure the complex profile structural parts, and to solve the problem of interface debonding after the composite material and the metal cabin are integrally formed.

In order to solve the above-mentioned technical problems, the present invention provides the following technical solutions:

A method for integrally forming a phenolic resin prepreg and a metal part, comprising:

(1) Steps of pretreatment of metal parts: sandblasting the profile surface to be bonded to the metal piece, and then apply glue on the metal profile surface;

(2) the step of compounding the transition layer on the profile treated in step (1);

(3) The step of laying up the phenolic resin prepreg: paint the phenolic resin adhesive on the surface compounded with the transition layer, and then lay the phenolic resin prepreg according to the designed layering sequence and thickness. ; The phenolic resin adhesive comprises 100 parts by weight of phenolic resin, 100-120 parts by weight of carboxyl-terminated nitrile rubber, and 0.5-1 part by weight of dispersant;

(4) the step of curing.

Preferably, the curing is performed using an autoclave curing method.

Preferably, the autoclave curing method is carried out as follows:

Heat up to 90-100℃, pressurize 0.5MPa, keep warm for 1-1.5h;

Heat up to 115-125℃, pressurize 0.8MPa, keep warm for 2-2.5h;

Raise the temperature to 155-165°C and keep the temperature for 4-4.5h;

Stop heating, cool down to below 60°C with pressure, and depressurize rate less than 2°C/min.

Preferably, the step (2) includes: the step of preparing the transition layer; the step of adhering the transition layer; and the step of vulcanizing.

Preferably, the transition layer is a 9621 nitrile rubber transition layer.

Preferably, the vulcanization is carried out at 90-95°C, and the vulcanization time is preferably 2-2.5h.

Preferably, the step of preparing the transition layer includes: dividing the profile area of the metal body, cutting the size of the 9621 nitrile rubber, and wiping the 9621 nitrile rubber clean with acetone.

Preferably, the step of adhering the transition layer includes: applying glue on the profile surfaces of the 9621 nitrile rubber and the metal body respectively, and then adhering to the metal body in sequence according to the divided areas.

Preferably, the dispersant is selected from polyvinyl alcohol and/or polypyrrolidone.

Preferably, after curing, a machining step is further included: performing three-dimensional digital model processing on the outer contour of the cured product.

beneficial effect

The above-mentioned technical scheme of the present invention has the following advantages:

Metal blasting before bonding can "roughen" the surface and improve the bonding quality. In theory, the metal parts can be used within three days after sandblasting. After sandblasting treatment, apply a thin layer of glue on the surface in time to prevent the sandblasting area from being oxidized and affecting the bonding quality of the rubber sheet.

When traditionally using 9621 rubber film or other epoxy adhesives as the strain isolation layer, only one adhesive is selected. However, the adhesive forces of the two interfaces of the three substances cannot be "dynamically balanced". The adhesion of the transition layer is large, so the composite material and the transition layer are often debonded. The present invention takes "dynamic balance" as the starting point and adds another modified adhesive, wherein the "affinity" between the carboxyl-terminated nitrile rubber filler and the rubber sheet and the "affinity" between the bulk phenolic and the composite material improve the transition layer The adhesion between the rubber sheet and the composite material is sufficient to balance the adhesion of the other interface, thus ensuring the quality of the interface adhesion.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

In a first aspect, the present invention provides a method for integrally molding a phenolic resin prepreg and a metal part, the method comprising:

(1) Steps of pretreatment of metal parts: sandblasting the surface of the metal parts to be bonded, and then apply glue on the metal surface. Before sandblasting, the surface of the metal parts to be bonded can also be wiped clean with alcohol or acetone. After sandblasting, you can wipe the sandblasted surface clean with alcohol or acetone, and then apply glue after drying. The glue can be selected? .

(2) The step of compounding a transition layer on the profile treated in step (1). This step specifically includes:

(21) The step of preparing the transition layer. The transition layer is preferably a 9621 nitrile-butadiene rubber transition layer, and can be a 9621 nitrile-butadiene rubber sheet in form. This step can be carried out as follows: Divide the profile area of the metal body, cut the size of the 9621 nitrile rubber, and wipe the 9621 nitrile rubber with acetone. (22) The step of bonding the transition layer. This step can be carried out as follows: respectively apply glue on the profile surfaces of 9621 nitrile rubber and the metal body, and then adhere to the metal body in sequence according to the divided areas. The glue used here can be epoxy glue, such as epoxy resin solution.

(23) The step of vulcanization, the vulcanization is preferably carried out at 90-95°C, for example, it can be 90°C, 91°C, 92°C, 93°C, 94°C, 95°C, preferably 2-2.5°C vulcanization at this temperature h.

(3) The step of laying up the phenolic resin prepreg: paint the phenolic resin adhesive on the surface compounded with the transition layer, and then lay the phenolic resin prepreg according to the designed layering sequence and thickness. ; The phenolic resin adhesive comprises 100 parts by weight of phenolic resin, 100-120 parts by weight of carboxyl-terminated nitrile rubber, and 0.5-1 part by weight of dispersant. If the proportion of phenolic resin is too large, the curing of the glue will be brittle; The proportion of carboxyl-terminated nitrile rubber is too large, and the glue is too viscous, which affects the manufacturability. The dispersant may be polyvinyl alcohol and/or polypyrrolidone.

(4) the step of curing. The present invention preferably adopts an autoclave curing method for curing, and the autoclave curing method is carried out according to the following method:

Heat up to 90-100℃, pressurize 0.5MPa, keep warm for 1-1.5h;

Heat up to 115-125℃, pressurize 0.8MPa, keep warm for 2-2.5h;

Raise the temperature to 155-165°C and keep the temperature for 4-4.5h;

Stop heating, cool down to below 60°C with pressure, and depressurize rate less than 2°C/min.

After curing, a machining step may also be included: performing three-dimensional digital model processing on the outer contour of the cured product.

The following are examples of the present invention.

Example 1

To prepare the external heat protection of a complex-shaped aircraft (cabin) of a certain project, the integrated molding process includes the following steps:

1. Pretreatment of the cabin: Wipe the metal surface to be bonded with alcohol, and then perform sand blasting. After blowing the sand, scrub the surface with alcohol, wait for it to dry, and then apply the epoxy resin glue for the first time;

2. Preparation of nitrile rubber transition layer: divide the cabin profile area, pre-cut 9621 nitrile rubber with the same size as the profile, wipe clean with acetone front and back, and wait for use;

3. Bonding between rubber and cabin: Apply glue on the rubber sheet and the sand-blown surface of the cabin respectively, then bond them to the cabin in sequence according to the pre-divided areas, deal with the seam area, and then vacuumize Pre-vulcanize in an oven at 90°C for 2h;

4. Prepreg layering: apply phenolic resin adhesive on the surface of the cabin after step 3. The formula of the phenolic resin adhesive is: 100 parts by weight of phenolic resin, 100 parts by weight of carboxyl-terminated nitrile rubber, and 0.5 parts by weight of dispersant polyvinyl alcohol parts by weight, and then lay up layers according to the designed layering sequence and thickness;

5. Autoclave curing: vacuumize the product after step 4 and push it into the autoclave to wait for curing. The curing procedure is as follows: room temperature—start to heat up (fixed temperature 90°C)—90°C—pressurize 0.5MPa, hold for 1h—heat up (constant temperature 120°C)—120°C—pressurize 0.8MPa, hold for 2h— Heating up (fixed temperature 160℃)——160——Keep warm for 4h, turn off the heating, cool down to below 60℃ with pressure (the cooling rate is less than 2℃/min), and take out the tank;

6. Machining: 3D digital model processing is performed on the outer contour of the integrally solidified product, and the final product is obtained after processing.

Refer to the standard GJB 1038.1A-2004 ultrasonic inspection, use NDTS-90 simulator to test, set the dB value to 45, and no debonding area is found within the probe accuracy range.

Example 2

To prepare the external heat protection of a complex-shaped aircraft (cabin) of a certain project, the integrated molding process includes the following steps:

1. Pretreatment of the cabin: Wipe the metal surface to be bonded with alcohol, and then perform sand blasting. After blowing the sand, wipe the surface with alcohol, and dry it for the next day;

2. Preparation of nitrile rubber transition layer: divide the cabin profile area, pre-cut 9621 nitrile rubber with the same size as the profile, wipe clean with acetone front and back, and wait for use;

3. Bonding between rubber and cabin: Apply glue on the rubber sheet and the sand-blown surface of the cabin respectively, then bond them to the cabin in sequence according to the pre-divided areas, deal with the seam area, and then vacuumize Pre-vulcanize in an oven at 90°C for 2h;

4. Prepreg layering: apply phenolic resin adhesive on the surface of the cabin after step 3. The formula of the phenolic resin adhesive is: 100 parts by weight of phenolic resin, 100 parts by weight of carboxyl-terminated nitrile rubber, and 0.5 parts by weight of dispersant polyvinyl alcohol parts by weight, and then lay up layers according to the designed layering sequence and thickness;

5. Autoclave curing: vacuumize the product after step 4 and push it into the autoclave to wait for curing. The curing procedure is as follows: room temperature—start to heat up (fixed temperature 90°C)—190°C—pressurize 0.5MPa, hold for 1h—heat up (constant temperature 120°C)—120°C—pressurize 0.8MPa, hold for 2h— Heating (constant temperature 160°C) - 160°C - keep warm for 4h, turn off the heating, cool down to below 60°C with pressure (cooling rate less than 2°C/min), take out the tank;

6. Machining: 3D digital model processing is performed on the outer contour of the integrally solidified product, and the final product is obtained after processing.

Referring to the standard GJB 1038.1A-2004 ultrasonic inspection, the NDTS-90 simulator was used to test, and the dB value was set to 45. Within the accuracy range of the probe, three areas of debonding were measured, and the areas were 5cm×7.5cm, 4.5cm× 8cm, 12cm×3.5cm, both of which are the debonding between the metal cabin and the rubber transition layer.

Example 3

To prepare the external heat protection of a complex-shaped aircraft (cabin) of a certain project, the integrated molding process includes the following steps:

1. Pretreatment of the cabin: Wipe the metal surface to be bonded with acetone, and then carry out sand blasting treatment. After blowing the sand, wipe the surface with acetone immediately, wait for it to dry, and apply the epoxy resin glue for the first time;

2. Preparation of nitrile rubber transition layer: divide the cabin profile area, pre-cut 9621 nitrile rubber with the same size as the profile, wipe clean with acetone front and back, and wait for use;

3. Bonding between rubber and cabin: Apply glue on the rubber sheet and the sand-blown surface of the cabin respectively, then bond them to the cabin in sequence according to the pre-divided areas, deal with the seam area, and then vacuumize Pre-vulcanize in an oven at 90°C for 2h;

4. Prepreg layering: After step 3, the surface of the cabin is layered according to the designed layering sequence and thickness;

5. Autoclave curing: vacuumize the product after step 4 and push it into the autoclave to wait for curing. The curing procedure is as follows: room temperature—start to heat up (fixed temperature 90°C)—90°C—pressurize 0.5MPa, hold for 1h—heat up (constant temperature 120°C)—120°C—pressurize 0.8MPa, hold for 2h— Heating (constant temperature 160°C) - 160°C - keep warm for 4h, turn off the heating, cool down to below 60°C with pressure (cooling rate less than 2°C/min), take out the tank;

6. Machining: 3D digital model processing is performed on the outer contour of the integrally solidified product, and the final product is obtained after processing.

Referring to the standard GJB 1038.1A-2004 ultrasonic inspection, the NDTS-90 simulator was used to test, and the dB value was set to 45. Within the accuracy range of the probe, the four defect areas measured were 2.5cm×4cm, 3cm×5.5cm , 4.5cm×7cm, and 10cm×3.5cm, all of which are the debonding between the transition layer and the composite material.

Example 4

To prepare the external heat protection of a complex-shaped aircraft (cabin) of a certain project, the integrated molding process includes the following steps:

1. Pretreatment of the cabin: Wipe the metal surface to be bonded with alcohol, and then perform sand blasting. After blowing the sand, wipe the surface with alcohol, wait for it to dry, and apply the glue for the first time;

2. Preparation of nitrile rubber transition layer: Divide the cabin profile area, pre-cut 9621 nitrile rubber with the same size as the profile, wipe the front and back with acetone, and wait for use;

3. Bonding between rubber and cabin: Apply glue on the rubber sheet and the sand-blown surface of the cabin respectively, then bond them to the cabin in sequence according to the pre-divided areas, deal with the seam area, and then vacuumize Pre-vulcanize in an oven at 90°C for 2h;

4. Prepreg layering: apply the same glue on the surface of the cabin after step 3, and then layer the layers according to the designed layering sequence and thickness;

5. Autoclave curing: vacuumize the product after step 4 and push it into the autoclave to wait for curing. The curing procedure is as follows: room temperature—start to heat up (constant temperature 90°C)—9°C—pressurize 0.5MPa, hold for 1h—heat up (constant temperature 120°C)—120°C 9—pressurize 0.8MPa, hold for 2h— - heating up (fixed temperature 160 °C) - 160 °C 9 - holding for 4 hours, turn off the heating, cool down to below 60 °C with pressure (the cooling rate is less than 2 °C/min), and take out the tank;

6. Machining: 3D digital model processing is performed on the outer contour of the integrally solidified product, and the final product is obtained after processing.

Referring to the standard GJB 1038.1A-2004 ultrasonic inspection, the NDTS-90 simulator was used to test, and the dB value was set to 45. Within the accuracy range of the probe, the two defect areas measured were 3cm×4.5cm, 7cm×5.5cm , both of which are the debonding between the transition layer and the composite material.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still be The technical solutions described in the foregoing embodiments are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. a phenolic resin prepreg and a metal part integral molding method, is characterized in that, comprises: (1) Steps of pretreatment of metal parts: sandblasting the profile surface to be bonded to the metal piece, and then apply glue on the metal profile surface; (2) the step of compounding the transition layer on the profile treated in step (1); (3) The step of laying up the phenolic resin prepreg: paint the phenolic resin adhesive on the surface compounded with the transition layer, and then lay the phenolic resin prepreg according to the designed layering sequence and thickness. ; The phenolic resin adhesive comprises 100 parts by weight of phenolic resin, 100-120 parts by weight of carboxyl-terminated nitrile rubber, and 0.5-1 part by weight of dispersant; (4) the step of curing. 2. The method according to claim 1, wherein Cured by autoclave curing method. 3. The method of claim 2, wherein Described autoclave curing method is carried out according to the following method: Heat up to 90-100℃, pressurize 0.5MPa, keep warm for 1-1.5h; Heat up to 115-125℃, pressurize 0.8MPa, keep warm for 2-2.5h; Raise the temperature to 155-165°C and keep the temperature for 4-4.5h; Stop heating, cool down to below 60°C with pressure, and depressurize rate less than 2°C/min. 4. The method of claim 1, wherein The step (2) includes: the step of preparing the transition layer; the step of adhering the transition layer; and the step of vulcanization. 5. The method according to claim 4, characterized in that, The transition layer is a 9621 nitrile rubber transition layer. 6. The method of claim 5, wherein The vulcanization is carried out at 90-95°C, and the vulcanization time is preferably 2-2.5h. 7. The method of claim 5, wherein: The steps of preparing the transition layer include: dividing the profile area of the metal body, cutting the size of the 9621 nitrile rubber, and wiping the 9621 nitrile rubber clean with acetone. 8. The method of claim 7, wherein The step of adhering the transition layer includes: applying glue on the profile surfaces of the 9621 nitrile butadiene rubber and the metal body respectively, and then adhering to the metal body in sequence according to the divided areas. 9. The method of claim 1, wherein The dispersant is selected from polyvinyl alcohol and/or polypyrrolidone. 10. The method of claim 1, wherein: After curing, a machining step is also included: three-dimensional digital model processing is performed on the outer contour of the cured product.