CN117402562A - Method for treating joint gap between plastic and metal - Google Patents
Method for treating joint gap between plastic and metal Download PDFInfo
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- CN117402562A CN117402562A CN202311200827.2A CN202311200827A CN117402562A CN 117402562 A CN117402562 A CN 117402562A CN 202311200827 A CN202311200827 A CN 202311200827A CN 117402562 A CN117402562 A CN 117402562A
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- glass fiber
- plastic
- polyurethane
- sealant
- spraying
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- 238000000034 method Methods 0.000 title claims abstract description 61
- 229920003023 plastic Polymers 0.000 title claims abstract description 41
- 239000004033 plastic Substances 0.000 title claims abstract description 41
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 38
- 239000002184 metal Substances 0.000 title claims abstract description 38
- 239000003365 glass fiber Substances 0.000 claims abstract description 42
- 239000000565 sealant Substances 0.000 claims abstract description 35
- 239000011248 coating agent Substances 0.000 claims abstract description 30
- 238000000576 coating method Methods 0.000 claims abstract description 30
- 239000003822 epoxy resin Substances 0.000 claims abstract description 26
- 229920000647 polyepoxide Polymers 0.000 claims abstract description 26
- 238000004140 cleaning Methods 0.000 claims abstract description 20
- 239000002318 adhesion promoter Substances 0.000 claims abstract description 12
- 238000005096 rolling process Methods 0.000 claims abstract description 6
- 239000004588 polyurethane sealant Substances 0.000 claims abstract description 5
- 239000004814 polyurethane Substances 0.000 claims description 38
- 229920002635 polyurethane Polymers 0.000 claims description 38
- 238000005507 spraying Methods 0.000 claims description 32
- 239000003973 paint Substances 0.000 claims description 22
- 239000004593 Epoxy Substances 0.000 claims description 18
- 238000005498 polishing Methods 0.000 claims description 16
- 229920000728 polyester Polymers 0.000 claims description 16
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- 244000137852 Petrea volubilis Species 0.000 claims description 10
- 229910000838 Al alloy Inorganic materials 0.000 claims description 9
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- 230000007547 defect Effects 0.000 claims description 5
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- 238000010345 tape casting Methods 0.000 claims description 2
- 238000005336 cracking Methods 0.000 abstract description 12
- 238000007789 sealing Methods 0.000 abstract description 7
- 238000004381 surface treatment Methods 0.000 abstract description 3
- 239000010410 layer Substances 0.000 description 28
- 239000003795 chemical substances by application Substances 0.000 description 26
- 238000001723 curing Methods 0.000 description 20
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- 239000010408 film Substances 0.000 description 9
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
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- 238000010586 diagram Methods 0.000 description 6
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- 150000002739 metals Chemical class 0.000 description 4
- 239000007921 spray Substances 0.000 description 4
- 229940008841 1,6-hexamethylene diisocyanate Drugs 0.000 description 3
- 239000002390 adhesive tape Substances 0.000 description 3
- 230000032683 aging Effects 0.000 description 3
- 239000012459 cleaning agent Substances 0.000 description 3
- RRAMGCGOFNQTLD-UHFFFAOYSA-N hexamethylene diisocyanate Chemical compound O=C=NCCCCCCN=C=O RRAMGCGOFNQTLD-UHFFFAOYSA-N 0.000 description 3
- 229920002126 Acrylic acid copolymer Polymers 0.000 description 2
- 239000004972 Polyurethane varnish Substances 0.000 description 2
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- 241001261506 Undaria pinnatifida Species 0.000 description 2
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- UYAAVKFHBMJOJZ-UHFFFAOYSA-N diimidazo[1,3-b:1',3'-e]pyrazine-5,10-dione Chemical compound O=C1C2=CN=CN2C(=O)C2=CN=CN12 UYAAVKFHBMJOJZ-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 239000012948 isocyanate Substances 0.000 description 1
- 150000002513 isocyanates Chemical group 0.000 description 1
- 239000002075 main ingredient Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
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- 238000013008 moisture curing Methods 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
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- 238000010008 shearing Methods 0.000 description 1
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J5/00—Adhesive processes in general; Adhesive processes not provided for elsewhere, e.g. relating to primers
- C09J5/02—Adhesive processes in general; Adhesive processes not provided for elsewhere, e.g. relating to primers involving pretreatment of the surfaces to be joined
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/24—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials for applying particular liquids or other fluent materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/50—Multilayers
- B05D7/56—Three layers or more
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61D—BODY DETAILS OR KINDS OF RAILWAY VEHICLES
- B61D17/00—Construction details of vehicle bodies
- B61D17/04—Construction details of vehicle bodies with bodies of metal; with composite, e.g. metal and wood body structures
- B61D17/043—Construction details of vehicle bodies with bodies of metal; with composite, e.g. metal and wood body structures connections between superstructure sub-units
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06G—MECHANICAL OR PRESSURE CLEANING OF CARPETS, RUGS, SACKS, HIDES, OR OTHER SKIN OR TEXTILE ARTICLES OR FABRICS; TURNING INSIDE-OUT FLEXIBLE TUBULAR OR OTHER HOLLOW ARTICLES
- D06G1/00—Beating, brushing, or otherwise mechanically cleaning or pressure cleaning carpets, rugs, sacks, hides, or other skin or textile articles or fabrics
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2503/00—Polyurethanes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2504/00—Epoxy polymers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2508/00—Polyesters
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J2463/00—Presence of epoxy resin
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J2475/00—Presence of polyurethane
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Wood Science & Technology (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Textile Engineering (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
Abstract
The invention belongs to the technical field of vehicle sealing and surface treatment, and discloses a method for treating a plastic and metal connecting gap. The method for treating the joint gap between the plastic and the metal comprises the following steps: (1) cleaning treatment; (2) adhesion promoter treatment; (3) coating sealant: coating sealant on the gap of the area to be connected, strickling and solidifying; and (4) leveling: cleaning the region to be connected treated in the step (3), coating epoxy resin on the surface of the region to be connected, paving a glass fiber felt with the surface coated with the epoxy resin on the surface of the region to be connected, rolling the glass fiber felt, continuously paving the glass fiber felt with the surface coated with the epoxy resin, and curing the glass fiber felt at the upper layer at least 2mm wider than the glass fiber felt at the lower layer; the sealant is polyurethane sealant. The method of the invention ensures that the plastic and the metal are tightly connected, avoids the secondary cracking of the joint and forms a complete whole with the plastic and the metal.
Description
Technical Field
The invention belongs to the technical field of vehicle sealing and surface treatment, and particularly relates to a method for treating a plastic and metal connecting gap.
Background
Cracks of different lengths often occur in the gaps at the connection of the fixed cover (e.g. glass reinforced plastic) of the cab of the rail transit vehicle and the vehicle body (e.g. aluminum alloy). The situation that the crack still has the condition of cracking again after repair treatment belongs to inertial mass problem, and this kind of condition can cause great influence to sealing performance and appearance quality of vehicle. In the advanced repair process of the vehicle, the surface coating and the sealant layer are cracked through layer-by-layer polishing analysis of the cracking area, and the damage mode of the sealant layer comprises near-wall cohesive damage and adhesion damage. Currently, there is a need in the industry for an effective method to solve the problem of cracking at the connection of the stationary cover to the vehicle body.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems in the prior art described above. To this end, the invention proposes a method for treating the joint seam between plastic and metal. The method can solve the problem of cracking of the connecting gap between the plastic and the metal and the problem of appearance quality of the connecting gap between the plastic and the metal. The method is applied to the gap at the joint of the cab fixing cover (for example, glass fiber reinforced plastic) and the vehicle body (for example, aluminum alloy), and can solve the problems of gap cracking and appearance quality.
The invention is characterized in that: according to the invention, the gap between the plastic and the metal is filled by selecting the specific adhesive (namely the sealant), and after solidification, the glass fiber felt and the epoxy resin are used for leveling treatment along the glue gap for a circle, so that the plastic and the metal are tightly connected, the secondary cracking of the joint is avoided, and the plastic and the metal form a complete whole.
The invention fills and seals the gap between plastics (such as a cab fixing cover of a vehicle, usually glass fiber reinforced plastic) and metals (such as aluminum alloy) by using the low-modulus high-elasticity adhesive, and can effectively avoid the cracking of the adhesive joint caused by thermal stress in the running process of the vehicle. The surface of the glue line is leveled by adding the glass fiber felt and the epoxy resin, so that the problems of uneven surface and cracking of the epoxy resin coating caused by shrinkage of the adhesive are effectively solved. The joint treatment of the adhesive, the glass fiber felt and the epoxy resin ensures that gaps between plastics and metals are well filled and are not easy to crack.
In addition, after the leveling treatment, the surface of the formed glass fiber felt and the epoxy resin plastic layer is further improved in surface flatness and appearance quality through a composite coating of epoxy primer, unsaturated polyester putty, polyurethane intermediate coat and polyurethane finish coat. Thereby solving the appearance quality problem of the joint of the plastic and the alloy well, and ensuring smooth and beautiful appearance connection.
A first aspect of the invention provides a method of treating a plastic to metal joint gap.
Specifically, a method for treating a joint gap between plastic and metal comprises the following steps:
(1) Cleaning: cleaning the plastic and metal to-be-connected area, polishing the to-be-connected area, and cleaning;
(2) Adhesion promoter treatment: wiping the area to be connected with the adhesion promoter, and airing;
(3) And (3) coating and beating a sealant: coating sealant on the gap of the area to be connected, strickling and solidifying;
(4) Leveling: cleaning the region to be connected treated in the step (3), coating epoxy resin on the surface of the region to be connected, paving a glass fiber felt with the surface coated with the epoxy resin on the surface of the region to be connected, rolling the glass fiber felt, continuously paving the glass fiber felt with the surface coated with the epoxy resin, and curing the glass fiber felt at the upper layer at least 2mm wider than the glass fiber felt at the lower layer;
the sealant is polyurethane sealant.
Preferably, the polyurethane sealant at least meets any one of the following conditions:
(1) The tensile strength is more than or equal to 7MPa;
(2) The shearing strength is more than or equal to 4MPa;
(3) The elongation at break is more than or equal to 400 percent;
(4) The curing speed is more than or equal to 3mm/24h;
(5) The glass transition temperature is less than or equal to 60 ℃;
(6) The right-angle tearing strength without cutting is more than or equal to 15N/mm.
Preferably, in the step (1), the plastic is a cab fixing cover; further preferably, the plastic is glass fiber reinforced plastic.
Preferably, in step (1), the metal is a vehicle body; further preferably, the metal is an aluminum alloy.
Preferably, in the step (1), the surface of the area to be connected between the plastic and the metal is cleaned to remove grease and dust.
Preferably, the cleaning process comprises the following steps: the surface of the area to be connected between the plastic and the metal is dipped with clean and non-dehairing wiping paper to wipe the surface of the area to be connected between the plastic and the metal, so that grease and dust are removed.
Preferably, in the step (1), the surface of the area to be connected is polished by using 80-150 mesh sand paper until the body color of the base material (plastic and metal) is exposed.
Preferably, in the step (1), the specific process of cleaning treatment is as follows: the surface of the area to be connected between the plastic and the metal is dipped with clean and non-dehaired wiping paper, and the cleaning agent is dried for more than 10 minutes. For example, air-dried for 11-100 minutes.
Preferably, in the step (2), the adhesion promoter includes an activator and a primer, which are commercially available conventional products, for example, the adhesion promoter is a Sika Aktivator activator and a Sika206 g+p primer, wherein the Sika Aktivator activator is a silane coupling agent and the Sika206 g+p primer is an isocyanate homopolymer.
Preferably, in step (2), the drying time is 15 minutes or longer, for example, 16 to 100 minutes.
Preferably, in step (2), the area to be joined is wiped with a wiping paper or a sponge block dipped with an adhesion promoter, and the wiping back and forth, i.e., one-way wiping, is prohibited.
Preferably, in the step (2), the thinner the film layer formed by wiping the adhesion promoter, the better the film layer, the more the film layer needs to fully cover the area to be connected without exposing the bottom.
Preferably, in the step (3), a pneumatic or electric glue gun is used for coating and beating the sealant in the gap of the to-be-connected area, and a glue nozzle penetrates into the bottom of the gap as far as possible during glue injection, and the sealant is compacted and scraped to be flat by a scraping plate, so that sealing is ensured to be free of holes.
Preferably, in the step (3), aiming at the poor appearance parts such as corners, interfaces and the like, the sealant repairing agent is used for finishing, so that the flatness and the attractiveness of the sealant are ensured.
Preferably, in step (3), the curing is performed at room temperature for 48 hours or more. For example, curing for 50-100 hours.
Preferably, in the step (3), when the gap depth exceeds 12mm, the sealant is coated and applied for multiple times, and the adhesion promoter treatment (namely, the adhesion promoter is coated on the surface of the sealant) is performed according to the step (2) before each sealant coating and application.
Preferably, in the step (4), the specific cleaning process is as follows: and (3) dipping the cleaning agent into clean and hair-free wiping paper to wipe the to-be-connected area until grease and dust are removed, polishing the cleaned surface by using 80-150-mesh sand paper until the color of the substrate body is exposed, dipping the cleaning agent into the wiping paper to wipe the surface, and airing for more than 10 minutes.
Preferably, in step (4), the curing is at room temperature for more than 24 hours, for example 15-35 hours.
Preferably, in the step (4), the bubbles at the bottom layer are removed by rolling.
Preferably, in step (4), the number of layers of the glass fiber mat is at least 3, for example 3-10.
Preferably, after the step (4), the method further comprises the steps of spraying the epoxy primer in the step (5), scraping and coating elastic polyester putty in the step (6), spraying polyurethane intermediate coat in the step (7), and spraying polyurethane colored paint in the step (8).
Preferably, the specific process of the epoxy primer spraying treatment in the step (5) is as follows: polishing the surface of the glass fiber felt by using 80-150-mesh sand paper, cleaning and dedusting by using a dust-binding cloth, preparing an epoxy primer, spraying the epoxy primer on the surface of the glass fiber felt for 2-5 times by adopting a wet-on-wet spraying process, drying the surface for about 30-40min between each time, and curing at room temperature for more than 16 hours after the whole spraying is finished.
Preferably, the specific process of the step (6) of knife coating elastic polyester putty is as follows: the elastic polyester putty is coated on the surface of the epoxy primer by using a soft scraper, wherein the elastic polyester putty is usually required to be coated for 2 times or 4 times, a longitudinal and transverse staggered blade coating mode is adopted between every two times, the thickness of each time of blade coating is not more than 1mm, the total thickness is not more than 3mm until the surface flatness meets the requirement, and the epoxy primer is cured for more than 3 hours at room temperature.
Preferably, the specific process of spraying the polyurethane mid-coat paint in the step (7) is as follows: after the polyurethane intermediate coat is sprayed, the polyurethane intermediate coat is cured for more than 16 hours at room temperature, meanwhile, the surface flatness of a region to be connected is checked, if the region to be connected is concave, elastic polyester putty is further used for repairing, after the polyurethane intermediate coat is dried and polished, white polyurethane finish coat is sprayed, defects are found under a high-light condition, and if the defects exist, the elastic polyester putty is used for repairing again.
Preferably, the specific process of spraying the polyurethane color paint in the step (8) is as follows: according to the art designer's requirements, polyurethane finish paint with corresponding color number is sprayed on the paint surface in the spraying polyurethane.
In a second aspect the invention provides the use of a method of treating a plastic to metal joint gap.
The method for processing the connecting gap between the plastic and the metal is applied to processing the connecting gap between the fixing cover of the cab of the vehicle and the vehicle body.
Preferably, the vehicle is a rail transit vehicle.
Compared with the prior art, the invention has the following beneficial effects:
(1) According to the invention, the gap between the plastic and the metal is filled by selecting the specific adhesive (namely the sealant), and after solidification, the glass fiber felt and the epoxy resin are used for leveling treatment along the glue gap for a circle, so that the plastic and the metal are tightly connected, the secondary cracking of the joint is avoided, and the plastic and the metal form a complete whole.
(2) The invention fills and seals the gap between plastics (such as a cab fixing cover of a vehicle, usually glass fiber reinforced plastic) and metals (such as aluminum alloy) by using the low-modulus high-elasticity adhesive, and can effectively avoid the cracking of the adhesive joint caused by thermal stress in the running process of the vehicle. The surface of the glue line is leveled by adding the glass fiber felt and the epoxy resin, so that the problems of uneven surface and cracking of the epoxy resin coating caused by shrinkage of the adhesive are effectively solved. The joint treatment of the adhesive, the glass fiber felt and the epoxy resin ensures that gaps between plastics and metals are well filled and are not easy to crack.
(3) After the leveling treatment, the surface of the formed glass fiber felt and the epoxy resin plastic layer is coated with a composite coating of epoxy primer, unsaturated polyester putty, polyurethane intermediate coat and polyurethane finish coat, so that the surface flatness and the appearance quality are further improved. Thereby solving the appearance quality problem of the joint of the plastic and the alloy well, and ensuring smooth and beautiful appearance connection.
Drawings
FIG. 1 is a view showing a gap formed at the joint of a cab mount cover and a vehicle body of a motor train unit according to embodiment 1;
FIG. 2 is a diagram showing the connection between the cab-fixed hood and the vehicle body of the vehicle set after the treatment in step (4) of example 1;
FIG. 3 is a diagram showing the connection between the cab-fixed hood and the vehicle body of the vehicle set after the treatment in step (6) of example 1;
FIG. 4 is a diagram showing the connection between the cab-fixed hood and the vehicle body of the vehicle set after the treatment in step (12) of example 1;
fig. 5 shows the cab fixing cover and the car body of the motor train unit treated by the method of example 1 after outdoor full weather aging for 2 years.
Detailed Description
In order to make the technical solutions of the present invention more apparent to those skilled in the art, the following examples will be presented. It should be noted that the following examples do not limit the scope of the invention.
The starting materials, reagents or apparatus used in the following examples are all available from conventional commercial sources or may be obtained by methods known in the art unless otherwise specified.
Example 1
The gap at the joint of the cab fixing cover (made of glass fiber reinforced plastic) and the car body (made of aluminum alloy) of the motor train unit is selected as an example (shown in figure 1), and the sealing bonding and the surface treatment are carried out by adopting the method.
A method of treating a plastic to metal joint gap comprising the steps of:
(1) Before operation, confirming the temperature and humidity of the surrounding environment, wherein the temperature is 15-35 ℃, the relative humidity is 50-75%, and the protective adhesive tapes are adhered along the two sides of a gap at the joint of the cab fixing cover and the vehicle body in a circle, and the adhesive tapes are required to be adhered after extending 3mm from the gap, so that the sealing surface meets the requirement of subsequent sizing;
(2) Dipping clean and unhairing wiping paper in absolute alcohol to wipe the surfaces of the fixed cover and the vehicle body to-be-connected area until grease and dust are removed, polishing the surfaces of the to-be-connected area by using a pneumatic polisher and matching 80-mesh sand paper until the body colors of the glass fiber reinforced plastics and the aluminum alloy are exposed (note: polishing the deeper area of the gap should finish cleaning polishing operation before the fixed cover is installed), dipping the wiping paper in absolute alcohol again to wipe the surfaces of the fixed cover and the vehicle body to-be-connected area, and airing for 15min;
(3) Wiping a region to be connected by using a nano sponge dip Sika Aktivator activator, airing for 20 minutes, brushing a thin film layer on the surface of the region to be connected by using a nano sponge dip Sika206 G+P primer, airing for 20 minutes, wherein the thinner the film layer is, the better the film layer is, the full coverage of the region to be connected is achieved, and the back and forth brushing is forbidden;
(4) Coating Sika265 single-component moisture curing polyurethane sealant on a gap between a fixed cover and a vehicle body to be connected by using a pneumatic sealant gun, wherein a sealant nozzle of the pneumatic sealant gun penetrates into the bottom of the gap as far as possible during sealant injection, so that sealant is ensured to overflow outwards from the bottom, the sealant is compacted and scraped by a scraper after the coating is finished, sealing is ensured to be free of holes, and the sealant needs to be cured for 50 hours under the room temperature condition after the coating;
(5) After the sealant is solidified, tearing off the protective adhesive tape, dipping clean and non-dehairing wiping paper in absolute alcohol to wipe the surfaces of the vehicle body, the fixed cover and the sealant until grease and dust are not contained, polishing the cleaned surface by using a pneumatic polisher and 80-mesh sand paper until the color of the fixed cover (glass fiber reinforced plastic) and the body of the vehicle body (aluminum alloy) are exposed, dipping the wiping paper in absolute alcohol again to wipe the surface, and airing for 15min;
(6) The glass fiber mats with cutting widths of 80mm, 100mm and 120mm and lengths of 5890mm are respectively reserved, and according to the mixture of a main agent (the main agent comprises epoxy resin (50%) and modified toughening resin (40%), the model of the main agent is MegaGlue 4006/B20) and a curing agent (the curing agent is modified amine, and the model of the main agent is MegaGlue HD 4006/B20) is 3:1, uniformly coating epoxy resin on the surfaces of the vehicle body, the fixed cover and the sealant, which need to be leveled, by using a roller to dip the epoxy resin, uniformly coating the epoxy resin on the surfaces of the glass fiber mats with the width of 80mm, paving the glass fiber mats on the surfaces of the vehicle body, the fixed cover and the sealant, which need to be leveled, and rolling the upper surfaces of the paved glass fiber mats by using the roller to dip the epoxy resin after finishing, so as to ensure that the epoxy resin completely infiltrates the glass fiber mat layer, and simultaneously, driving out bottom air bubbles in a rolling mode;
(7) After the glass fiber felt (first layer) with the width of 80mm is paved and adhered, the glass fiber felt (second layer) with the width of 100mm and the glass fiber felt (third layer) with the width of 120mm are paved and adhered in sequence by the same method, and the glass fiber felt is solidified for 30 hours at room temperature;
(8) After the glass fiber felt layer is solidified, polishing the surface of the glass fiber felt layer by using 80-mesh sand paper, cleaning and dedusting by using a dust-binding cloth, and mixing a main agent (mainly epoxy resin is used as a main agent, THD06WEP-200 is used as a main agent product model) and a curing agent (polyamide emulsion is used as a main component of the curing agent, WEP-200-G is used as a curing agent product model) according to the main agent (5: 1, preparing epoxy primer in a weight ratio, spraying the epoxy primer on the surface of the glass fiber felt layer for two times by using a high-pressure airless spray gun and adopting a wet-on-wet spraying process, wherein the surface is required to be dried for about 30 minutes in each time, and curing the epoxy primer for 20 hours at room temperature after the whole spraying is finished, wherein the average dry film thickness is controlled to be about 60 mu m;
(9) The surface of the epoxy primer was lightly sanded with sandpaper and cleaned with a dust cloth at a rate of 100:2.5, blending elastic polyester putty (Square Weikai of manufacturers, model UP 100) according to a weight ratio, leveling a region with larger pits in advance, fully scraping the elastic polyester putty by using a soft scraper after curing for 3 hours, transversely scraping the elastic polyester putty along the outer part of the fixed cover in the first time, vertically scraping the putty along the periphery of the fixed cover in the second time, slightly downwards regulating the consistency of the elastic polyester putty in the third time (gradually adding 2% of different diluents for 3 times, wherein the main component of the diluents is styrene, improving the fluidity of the putty until the pores and tiny pits on the surface can be fully filled), fully scraping by adopting a transverse scraping method and a vertical scraping method respectively, wherein the scraping thickness of each scraping method is not more than 1mm, the total thickness is 3mm until the surface smoothness meets the requirement, and curing for 4 hours at room temperature in each time to form a putty layer;
(10) Step-by-step polishing the putty layer by using 80-mesh, 120-mesh and 180-mesh sand paper and cleaning the putty layer by using dust removing cloth, wherein the steps are as follows: 1 (the polyurethane intermediate paint comprises a main agent and a curing agent, wherein the main agent is mainly acrylic resin emulsion, the model TBZ04 WIPU-100, the curing agent is mainly 1, 6-hexamethylene diisocyanate homopolymer, and the model WIPU-100-G), the surface of a putty layer is sprayed with the polyurethane intermediate paint for two times by using an air spray gun and adopting a wet-on-wet spraying process, the surface of each time is about 30 minutes, the polyurethane intermediate paint is cured at room temperature for 18 hours after the whole spraying is finished, and the average dry film thickness is controlled to be about 50 mu m, so as to form a polyurethane intermediate coating;
(11) Visually checking whether a obviously uneven area exists on the surface of the coating in polyurethane under the illumination of not less than 400Lx, if so, adopting a mode of repairing putty after polishing to treat, polishing the coating in polyurethane by using 240-mesh sand paper after finishing, and cleaning by using dust removing cloth, wherein the method comprises the following steps of: 1 (the white polyurethane finish paint comprises a main agent and a curing agent, wherein the main agent is mainly acrylic acid copolymer, the model TBS04B WPU-400. The main ingredient of the curing agent is 1, 6-hexamethylene diisocyanate homopolymer, the model WPU-400-G), an air spray gun is used for spraying the white polyurethane finish paint on the surface of a polyurethane middle coating layer twice by adopting a wet-on-wet spraying process, the surface of the white polyurethane finish paint is required to be dried for about 30 minutes each time, leveling is carried out for 2 hours after the whole spraying is finished, drying is carried out for 3 hours at 60 ℃, and drying is carried out for 9 hours at room temperature, wherein the average dry film thickness is controlled to be about 30 mu m;
(12) Visually checking whether pits or other defects exist on the surface of the white polyurethane finish paint layer again under the illumination of not less than 400Lx, if so, adopting a mode of locally repairing putty after polishing to treat, polishing the polyurethane finish paint layer once by using 320-mesh sand paper and cleaning by using dust removing cloth, and the method comprises the following steps of: 1, preparing a white polyurethane finish paint in a weight ratio, spraying the white polyurethane finish paint for two times by using an air spray gun and adopting a wet-on-wet spraying process, wherein the surface drying time is about 30 minutes between each time, and then spraying polyurethane varnish after the surface drying of the finish paint is carried out for 1 hour, wherein the preparation requirement of the polyurethane varnish is that the weight ratio of a main agent to a curing agent is 3:1 (the main agent is acrylic acid copolymer, the manufacturer's square wakame; the main component of the curing agent is 1, 6-hexamethylene diisocyanate homopolymer (80%) and propylene glycol diacetate (20%), the manufacturer's square wakame), leveling for 2 hours after the whole spraying is finished, drying for 2.5 hours at 60 ℃, and drying for 18 hours at room temperature, wherein the average dry film thickness is controlled to be about 50 μm.
FIG. 2 is a diagram showing the connection between the cab-fixed hood and the vehicle body of the vehicle set after the treatment in step (4) of example 1; FIG. 3 is a diagram showing the connection between the cab-fixed hood and the vehicle body of the vehicle set after the treatment in step (6) of example 1; FIG. 4 is a diagram showing the connection between the cab-fixed hood and the vehicle body of the vehicle set after the treatment in step (12) of example 1; it can be seen that the joint of the cab fixing cover and the vehicle body of the vehicle set has no cracks. Fig. 5 shows the cab fixing cover and the car body of the motor train unit treated by the method of example 1 after outdoor full weather aging for 2 years. Even after 2 years of full weathering, no cracks appear.
Comparative example 1
In comparison with example 1, the sealant used in comparative example 1 was a field chemical 309 sealant, and the rest of the procedure was the same as in example 1.
Comparative example 2
In comparison with example 1, the glass fiber mat of example 1 was not used in comparative example 2, and the rest was the same as in example 1. As a result, after the treatment of the method of comparative example 1, a crack of 50mm in length was formed at the junction of the vehicle body and the cab-fixed hood.
Product effect test
The cab fixed cover and the car body treated by the methods of example 1 and comparative examples 1-2 were tested under the conditions of full weather aging and on-line normal operation, and whether cracks appear at the joint of the cab fixed cover and the car body was observed, and the results are shown in table 1.
TABLE 1
As can be seen from Table 1, the cab fixing cover treated by the method of example 1 of the present invention is firmly connected with the vehicle body, and is not easy to crack, while the cab fixing cover treated by the method of comparative examples 1-2 is not firmly connected with the vehicle body, and is easy to crack. Therefore, the cab fixing cover treated by the method is firmly connected with the vehicle body, and is not easy to crack.
Claims (10)
1. A method of treating a plastic to metal joint gap comprising the steps of:
(1) Cleaning: cleaning the plastic and metal to-be-connected area, polishing the to-be-connected area, and cleaning;
(2) Adhesion promoter treatment: wiping the area to be connected with the adhesion promoter, and airing;
(3) And (3) coating and beating a sealant: coating sealant on the gap of the area to be connected, strickling and solidifying;
(4) Leveling: cleaning the region to be connected treated in the step (3), coating epoxy resin on the surface of the region to be connected, paving a glass fiber felt with the surface coated with the epoxy resin on the surface of the region to be connected, rolling the glass fiber felt, continuously paving the glass fiber felt with the surface coated with the epoxy resin, and curing the glass fiber felt at the upper layer at least 2mm wider than the glass fiber felt at the lower layer;
the sealant is polyurethane sealant.
2. The method of claim 1, wherein in step (1), the plastic is a cab-stationary cover; the metal is a vehicle body.
3. The method of claim 1, wherein in step (1), the plastic is glass fiber reinforced plastic; the metal is an aluminum alloy.
4. The method of claim 1, wherein in step (3), when the gap depth exceeds 12mm, the application of the sealant is performed in a plurality of times, and the adhesion promoter treatment is performed in step (2) before each application of the sealant.
5. The method of claim 1, wherein in step (4), the glass fiber mat is laid with at least 3 layers.
6. The method according to any one of claims 1 to 5, further comprising, after the step (4), a step (5) of spraying an epoxy primer, a step (6) of knife coating an elastic polyester putty, a step (7) of spraying a polyurethane mid-coat paint, and a step (8) of spraying a polyurethane colored paint.
7. The method of claim 6, wherein the specific process of the epoxy primer spraying treatment of step (5) is: polishing the surface of the glass fiber felt by using 80-150-mesh sand paper, cleaning and dedusting by using dust-binding cloth, preparing epoxy primer, spraying 2-5 times of epoxy primer on the surface of the glass fiber felt by adopting a wet-on-wet spraying process, drying for about 30-40min between each time, and curing at room temperature for more than 16 hours after the whole spraying is finished;
the specific process of the step (6) of blade coating elastic polyester putty comprises the following steps: the elastic polyester putty is coated on the surface of the epoxy primer by using a soft scraper, wherein the elastic polyester putty is usually required to be coated for 2 times or 4 times, a longitudinal and transverse staggered blade coating mode is adopted between every two times, the thickness of each time of blade coating is not more than 1mm, the total thickness is not more than 3mm until the surface flatness meets the requirement, and the epoxy primer is cured for more than 3 hours at room temperature.
8. The method according to claim 6, wherein the specific process of spraying the polyurethane mid-coat paint in the step (7) is as follows: after the polyurethane intermediate coat is sprayed, the polyurethane intermediate coat is cured for more than 16 hours at room temperature, meanwhile, the surface flatness of a region to be connected is checked, if the region to be connected is concave, elastic polyester putty is further used for repairing, after the polyurethane intermediate coat is dried and polished, white polyurethane finish coat is sprayed, defects are found under a high-light condition, and if the defects exist, the elastic polyester putty is used for repairing again.
9. The method according to claim 6, wherein the specific process of spraying the polyurethane color paint in the step (8) is as follows: according to the art designer's requirements, polyurethane finish paint with corresponding color number is sprayed on the paint surface in the spraying polyurethane.
10. Use of a method of treating a plastic-to-metal joint seam as claimed in any of claims 1 to 9 for treating a vehicle cab attachment hood-to-body joint seam.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311200827.2A CN117402562A (en) | 2023-09-15 | 2023-09-15 | Method for treating joint gap between plastic and metal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311200827.2A CN117402562A (en) | 2023-09-15 | 2023-09-15 | Method for treating joint gap between plastic and metal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117402562A true CN117402562A (en) | 2024-01-16 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311200827.2A Pending CN117402562A (en) | 2023-09-15 | 2023-09-15 | Method for treating joint gap between plastic and metal |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117402562A (en) |
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2023
- 2023-09-15 CN CN202311200827.2A patent/CN117402562A/en active Pending
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