JP2005118630A - Manufacturing method of steel sheet reinforcing material for car - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reinforcing material having a predetermined shape to the predetermined region of a steel sheet for a car at a low cost. <P>SOLUTION: The one-pack type curable resin SOL1 for an intermediate layer stored in a first tank 12 is applied to the predetermined region of the steel sheet W for the car and the one-pack type curable resin SOL2 for the reinforcing material stored in a second tank 14 is applied to the resin layer on the steel sheet W. Thereafter, both resins SOL1 and SOL2 are heated to be cured to such a degree that the surface layers of both resins SOL1 and SOL2 lose flowability but hold flowability internally. Subsequently, shower water washing, chemical forming treatment and electrodeposition coating are applied to the steel sheet W for the car and both resins SOL1 and SOL2 are internally solidified when the electrodeposited coating is dried and solidified to form an epoxy/urethane intermediate layer 40 having air bubbles 44 and an epoxy reinforcing layer 42. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing an automotive steel plate reinforcing material that reinforces an automotive steel plate such as a door panel connected to an automobile body.

  From the viewpoint of protecting the global environment, in order to improve the fuel efficiency of an automobile and suppress the exhaust gas emission amount, the components of the automobile have been reduced in weight. Specifically, it is possible to reduce the plate thickness of an automotive steel plate such as a door panel.

  However, a member having a small plate thickness has low rigidity. Therefore, in order to ensure rigidity, as shown in FIG. 4, it is widely practiced to provide the reinforcing material 2 at a predetermined portion of the door panel (automobile steel plate) 1. This type of reinforcing material 2 is, for example, a predetermined preformed body obtained by press-molding a steel workpiece with a synthetic resin such as rubber, bitumen, alkyd resin, epoxy resin, urethane resin, urea resin, or the like. It is produced by applying a chemical conversion treatment and electrodeposition coating to the preform, and then heating and curing the resin when drying the electrodeposited paint. In addition, a filler and an additive may be mixed with resin as needed.

  By the way, when providing the reinforcing material 2 in the door panel 1 as mentioned above, there exists a malfunction that resin deform | transforms by the shower water washing performed as pre-processing of a chemical conversion treatment, or falls. In order to avoid this problem, if the resin is heated to be cured in advance before washing with shower water, the oil applied in advance for rust prevention of the preform is seized. It becomes difficult to remove.

  As this measure, it is conceived to use a two-component curable resin that can be cured by adding a curing agent. In this case, the two-component curable resin can be cured without requiring heating, and therefore it is possible to avoid seizing the oil.

  However, since the two-component curable resin begins to cure immediately after the main agent and the curing agent are mixed, it is difficult to manage the tube and coating gun for applying the mixture because it must be avoided. Moreover, since the surplus of the mixture of a main ingredient and a hardening | curing agent cannot be stored, it is necessary to discard it, and thus problems such as disadvantages in cost have become obvious.

  Therefore, in Patent Document 1, a composition in which a specific plasticizer and acrylic particles are blended with a mixture of a thermally activated curing agent and an epoxy resin, and the composition is applied to a steel sheet, and then preheated to epoxy resin. It has been proposed to obtain a reinforcing material by physically swelling and acrylic gel.

JP-A-8-302278

  The present invention has been made in connection with the above-described technique, and can prevent the resin from being deformed or detached. For this purpose, it is possible to provide a reinforcing material having a predetermined shape at a predetermined portion. An object of the present invention is to provide a manufacturing method of a steel plate reinforcing material for automobiles.

In order to achieve the above object, the present invention includes a first step of applying a thermosetting resin that cures when heated to an automotive steel sheet;
A second step of heating the resin until the fluidity of the surface layer of the resin disappears while maintaining the fluidity of the resin inside;
After performing chemical conversion treatment and electrodeposition coating on the steel plate for automobiles, a third step of drying the electrodeposited paint and curing the interior of the resin to form a steel plate reinforcement for automobiles;
Have
A one-component curable resin is used as the resin.

  In the present invention, since it is cured until the fluidity of the surface layer disappears in the second step, the applied resin causes misalignment or diffuses during the water washing applied to the steel plate for automobiles thereafter. Can be avoided. Therefore, by hardening the resin to the inside in the third step, the automobile steel plate reinforcing material can be reliably provided at a predetermined site.

  In this case, since the fluidity of the surface layer is hardened until it disappears, it is possible to avoid the oil from being seized on the steel plate reinforcing material for automobiles.

  Further, even if the resin contains a filler or extender pigment, the resin is cured until the fluidity of the surface layer disappears, so the steel plate reinforcing material for automobiles is immersed in the chemical conversion solution. At this time, the elution of the filler and extender into the chemical conversion solution is avoided. In other words, it is possible to avoid contamination of the chemical conversion solution.

  In addition, in the present invention, since a one-part curable resin that is cured by heating is used, management is easier than in the case of using a two-part curable resin, and it is not necessary to discard the surplus. Cost can also be reduced.

  In addition, the technique described in the above-mentioned patent document 1 does not cure the epoxy resin as described in paragraph [0028] of the above-mentioned patent document 1, but physically uses the epoxy resin and the acrylic powder particles. It causes swelling. On the other hand, the second step of the present invention cures only the surface layer of a one-component curable resin such as an epoxy resin, and does not physically swell. In this respect, the present invention is different from the technique described in Patent Document 1.

  Here, in the second step, for example, by holding a temperature of 160 ° C. or higher for at least 3 minutes using a heater, the fluidity of the surface of the one-part curable resin is lost and the fluidity is maintained inside. It can be cured to a state. Alternatively, in the second step, infrared rays may be irradiated to maintain a temperature of 300 ° C. or higher for at least 2 minutes.

  Then, before the first step, a one-component curable resin containing a foaming agent is applied, and the one-component curable resin retains the fluidity inside the resin in the second step, while the surface layer of the resin It is preferable to provide an intermediate layer by curing until the fluidity of the resin disappears, and curing and foaming to the inside of the resin in the third step. This is because when the intermediate layer is present, the reinforcing effect is remarkably improved as compared with the case where the reinforcing material is provided alone.

  Preferable examples of the one-component curable resin that is a raw material for the intermediate layer include a mixed resin of an epoxy resin and a urethane resin.

  When applying the one-component curable resin, which is the raw material of the intermediate layer, to the steel plate for automobiles, it is preferable to rotate the discharge pipe. Thereby, resin is apply | coated to the steel plate for motor vehicles in the state in which the edge part was curved. When the resin having the curved end portion is cured in this manner, the steel plate for automobiles is suppressed from being attracted when the resin contracts with the effect. For this reason, it can avoid that distortion arises in the steel plate for cars.

  As a suitable example of the one-component curable resin that is a raw material of the steel plate reinforcing material for automobiles, an epoxy resin can be exemplified.

  For the reasons described above, it is preferable to rotate the discharge pipe also when applying the one-component curable resin, which is the raw material of the reinforcing material, to the automobile steel plate. Of course, the same applies when no intermediate layer is provided.

  According to the present invention, since the one-component curable resin is used as a raw material for the reinforcing material, the management becomes easy and the cost can be reduced. Further, by hardening until the fluidity of the surface layer disappears in the second step, it is possible to avoid the resin from being displaced or diffused during subsequent water washing, so that the steel plate reinforcing material for automobiles Can be reliably provided at a predetermined site. In addition, in this case, it is possible to avoid seizing the oil present on the surface of the steel plate for automobiles.

  Hereinafter, preferred embodiments of the method for manufacturing a steel plate reinforcing material for automobiles according to the present invention will be described in detail with reference to the accompanying drawings.

  The manufacturing method of the steel plate reinforcing material for automobiles according to the present embodiment includes a first step of applying a resin to an automobile steel plate, a second step of heating only the surface layer by heating the resin, and bringing the resin into the interior. And a third step of curing.

  FIG. 1 shows a schematic overall view of a coating apparatus 10 for performing the first step. The coating apparatus 10 adopting the swirl method includes a first tank 12 storing a sol SOL1 of a mixed resin of an epoxy resin and a urethane resin, which is a raw material of an epoxy / urethane intermediate layer, which will be described later, and an epoxy reinforcing layer as a reinforcing material. A second tank 14 storing an epoxy resin sol SOL2 which is a raw material of the first pump 16, a first pump 16 for sucking a sol-state one-component curable resin from the first tank 12 and the second tank 14, respectively. It has a pump 18, a booster 20 for increasing the coating pressure, and a coating robot 24 having a discharge pipe 22 for discharging the sols SOL1 and SOL2. Pipings 26, 28, 30 are bridged between the first pump 16, the second pump 18 and the booster 20, and between the booster 20 and the coating robot 24. Between them, a switching valve 32 is arranged.

  In the following, a mixed resin sol SOL1 of an epoxy resin and a urethane resin stored in the first tank 12 is used as an intermediate layer one-part curable resin SOL1, and an epoxy resin sol SOL2 stored in the second tank 14 is used. Are each referred to as a one-component curable resin SOL2 for reinforcing material. Moreover, the one-component curable resin SOL1 for the intermediate layer and the one-component curable resin SOL2 for the reinforcing material are both one-component curable resins that are cured by heating.

  Here, as a suitable example of an epoxy resin, the thing of a bisphenol A type can be mentioned. Moreover, as a suitable example of a urethane resin, the one-component block urethane resin which is a well-known substance can be mentioned. This urethane resin is obtained by blocking the end group of a prepolymer obtained by polymerizing isocyanate in advance with a blocking agent such as an amine, an oxime compound, or a lactam compound, and this blocking agent is released when heated. Then, it reacts with an active hydrogen compound to form a urethane bond. Examples of the isocyanate include tolylene diisocyanate, methylene diphenyl diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, hydrogenated methylene diphenyl diisocyanate, and isophorone diisocyanate.

  In this case, the one-part curable resin SOL1 for the intermediate layer includes, for example, diazoaminobenzol, azoisobutylnitrile, benzolsulfohydrazide, azodicarbonamide, PP′-oxybenzolsulfohydrazide, benzylmonohydrazole and the like. A foaming agent such as an organic foaming agent or a thermally expandable capsule is added. The addition amount of the foaming agent is preferably 0.2 to 3% by weight. Moreover, you may make it add foaming adjuvants, such as a urea and its derivative (s), zinc white, a zinc compound, as needed.

  Furthermore, you may make it mix | blend a filler, an additive, etc. with respect to the one-component curable resin SOL1 for intermediate | middle layers. Suitable examples of fillers include calcium carbonate, barium sulfate, talc, clay, kaolin, mica, zinc white, titanium oxide, silicon oxide, aluminum oxide, plastic balloons, glass balloons, etc. There are certain substances. In particular, scaly materials such as mica and fiber-based fillers such as glass fibers are more preferable because they can constitute an epoxy / urethane intermediate layer having excellent rigidity.

  On the other hand, suitable examples of additives include extender pigments, dehydrating agents, hygroscopic agents, sagging inhibitors, thixotropic additives, dispersants, reaction catalysts, UV absorbers, high-boiling solvents for improving coating workability, epoxy Examples include reactive diluents, plasticizers, powder rubbers for increasing the oil level adhesion effect, zeolites, acicular calcium metasilicate, acrylic resins for increasing the steel plate reinforcing effect, and the like. The blending amount of these fillers and additives is preferably 10% by mass at the maximum.

  And as a suitable example of the one-component curable resin SOL2 for the reinforcing material, a bisphenol A type epoxy resin can be exemplified as described above. Moreover, you may make it mix | blend the above fillers and additives also to this one-component curable resin SOL2 for reinforcing materials.

  In the first step, as shown in FIG. 1, for the automotive steel plate W such as a door panel positioned at a predetermined position of the support board S, first, the one-layer curing type for the intermediate layer stored in the first tank 12. Resin SOL1 is applied. That is, the one-layer curable resin SOL1 for the intermediate layer is sucked under the action of the first pump 16, the discharge pressure is increased by the booster 20, and then discharged from the discharge pipe 22 of the coating robot 24.

  At the time of this application, in the swirl type application device 10, the discharge pipe 22 rotates helically. By this rotation operation, the one-part curable resin SOL1 for the intermediate layer is applied to the automobile steel plate W with the end portion being curved, as shown in FIG.

  When the discharge pipe 22 is linearly displaced while rotating as described above, the one-component curable resin SOL2 for reinforcing material is applied within a predetermined range of the steel plate W for automobiles.

  Then, the switching valve 32 operates, the pipe 26 is closed and the pipe 28 is opened. In accordance with this, the one-liquid curing type for reinforcing material is transferred from the second tank 14 to the booster 20 under the suction action of the second pump 18. Resin SOL2 is transferred. Finally, the one-component curable resin SOL2 for reinforcing material is discharged from the discharge pipe 22 of the coating robot 24 through the same process as described above, and is applied so as to be laminated on the one-component curable resin SOL1 for the intermediate layer. The Of course, also during this application, the discharge pipe 22 is displaced linearly while rotating helically. Therefore, the one-component curable resin SOL2 for the reinforcing material is laminated on the one-component curable resin SOL1 for the intermediate layer in a state where the end portion is curved.

  Next, the intermediate layer one-part curable resin SOL1 and the reinforcing member one-part curable resin SOL2 are heated in the second step.

  This heating is performed until the surface layers of both the resins SOL1 and SOL2 lose their fluidity and are cured so that the inside maintains the fluidity. More specifically, 40 ° C. tap water is discharged from an outlet having an opening diameter of 13.5 mm at approximately 7000 g / min for 30 seconds, and both resins SOL1 and SOL2 arranged at a distance of 400 mm below the outlet are provided. What is necessary is just to make it not to spread | diffuse.

  The heating conditions capable of curing both resins SOL1 and SOL2 to such a degree differ depending on the heating method. For example, in a heater in which warm air is supplied to both resins SOL1 and SOL2, it is preferable to maintain a temperature of 160 ° C. or higher for at least 3 minutes. The heating source may be gas or electricity. Moreover, when heating both resin SOL1 and SOL2 with the far-infrared apparatus which irradiates a far-infrared, it is preferable to hold | maintain the temperature of 300 degreeC or more for at least 2 minutes.

  In any case, it is not particularly necessary to heat the entire steel plate W for automobiles, and it is only necessary to heat both the applied resins SOL1 and SOL2. For this reason, as a heating device, a small-sized and power-saving device can be used. Therefore, equipment can be simplified and energy can be saved.

  Thus, after hardening both resin SOL1 and SOL2 to such an extent that the surface lose | disappears fluidity | liquidity, the steel plate W for motor vehicles is washed with shower water. At this time, if the temperature, the discharge amount, and the discharge time of the shower water are set as described above, it is possible to surely prevent the both resins SOL1 and SOL2 from diffusing or causing displacement.

  And the steel plate W for motor vehicles is immersed in the tank in which the chemical conversion liquid was stored. As described above, since both the resins SOL1 and SOL2 are cured to such a degree that the surfaces lose their fluidity, even if both the resins SOL1 and SOL2 contain fillers and extender pigments, Sometimes these fillers and extenders do not elute. Therefore, it is possible to reliably avoid contamination of the chemical conversion treatment liquid.

  After this chemical conversion treatment, oil components such as rust preventive oil and press molding lubricant are removed, electrodeposition coating is applied to the steel plate W for automobiles. That is, the paint is electrodeposited.

  Thereafter, in the third step, the electrodeposited paint is dried and solidified to provide a coating film. Specifically, the automobile steel plate W is passed through an oven at about 180 ° C. over about 20 to 30 minutes. In this drying step, both the one-part curable resin SOL1 for the intermediate layer and the one-part curable resin SOL2 for the reinforcing material are cured to the inside together with the paint. As a result, as shown in FIG. 40 and an epoxy reinforcing layer 42 are formed. Here, the epoxy reinforcing layer 42 has a slightly larger shrinkage than the epoxy / urethane intermediate layer 40.

  Note that, as described above, the one-part curable resin SOL1 for the intermediate layer is applied to the automobile steel plate W in a state where the end portion is curved. In this case, when the applied resin SOL1 is cured, the automotive steel plate W is suppressed from being attracted to the resin SOL1 that is cured and contracted. For this reason, it can avoid that distortion arises in the steel plate W for motor vehicles.

  Moreover, in this Embodiment, since the foaming agent and the foaming adjuvant are mixed with the one-component curable resin SOL1 for the intermediate layer, bubbles are generated during the curing of the resin SOL1. For this reason, many bubbles 44 exist in the formed epoxy / urethane intermediate layer 40. Thus, even if the air bubbles 44 are generated during the curing of the resin SOL1, the occurrence of distortion in the automotive steel plate W is avoided.

  Thus, by providing the epoxy / urethane intermediate layer 40, it is possible to avoid the occurrence of distortion in the automotive steel sheet W. In addition, in this case, there is an advantage that the reinforcing force is remarkably increased as compared with the single layer of the epoxy reinforcing layer 42.

  Furthermore, according to the present embodiment, since a one-component curable resin that is cured by heating is used, management is easier than in the case of using a two-component curable resin, and it is necessary to discard the surplus. There is no cost advantage.

  The epoxy / urethane intermediate layer 40 and the epoxy reinforcing layer 42 are made of the one-component curable resin SOL1 for intermediate layer and the one-component curable resin SOL2 for reinforcing material that are not diffused by washing with shower water. It is provided at a predetermined site. That is, according to the present embodiment, by hardening both the resins SOL1 and SOL2 to such an extent that the fluidity of the surface disappears, the strong epoxy reinforcing layer 42 can be reliably provided at a predetermined site. Moreover, seizure of oil can be avoided.

  In the above-described embodiment, the epoxy / urethane intermediate layer 40 is provided. However, it is not particularly necessary to provide such an intermediate layer 40, and only the epoxy reinforcing layer 42 may be provided. The material of the intermediate layer and the reinforcing layer is not particularly limited to epoxy resin / urethane resin and epoxy resin, and may be a one-component curable resin that can be cured before the oil is burned.

  Further, the resin may be discharged without causing the discharge pipe 22 to rotate helically.

It is a schematic whole view of the coating device for enforcing the manufacturing method of the steel plate reinforcing material for cars concerning this embodiment. It is a schematic plane explanatory drawing which shows the shape of resin apply | coated by the coating device of FIG. It is a schematic longitudinal cross-sectional explanatory view which shows the state by which the epoxy / urethane intermediate | middle layer and the epoxy reinforcement layer were formed in the surface of the steel plate for motor vehicles. It is principal part expansion explanatory drawing of the door panel in which the reinforcing material was formed in the predetermined | prescribed site | part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Door panel (steel plate for motor vehicles) 2 ... Reinforcement material 10 ... Coating device 12, 14 ... Tank 16, 18 ... Pump 22 ... Discharge pipe 24 ... Coating robot 40 ... Epoxy / urethane intermediate layer 42 ... Epoxy reinforcement layer 44 ... Bubble SOL1 ... One-component curable resin for intermediate layer SOL2 ... One-component curable resin for reinforcing material

Claims (8)

A first step of applying a thermosetting resin that cures when heated to a steel plate for automobiles;
A second step of heating the resin until the fluidity of the surface layer of the resin disappears while maintaining the fluidity of the resin inside;
After performing chemical conversion treatment and electrodeposition coating on the steel plate for automobiles, a third step of drying the electrodeposited paint and curing the interior of the resin to form a steel plate reinforcement for automobiles;
Have
The manufacturing method of the steel plate reinforcing material for motor vehicles characterized by using one-component curable resin as said resin.   2. The manufacturing method according to claim 1, wherein, in the second step, a temperature of 160 [deg.] C. or higher is maintained for at least 3 minutes using a heater.   2. The method of manufacturing a steel plate reinforcing material for an automobile according to claim 1, wherein, in the second step, infrared rays are irradiated and a temperature of 300 [deg.] C. or higher is maintained for at least 2 minutes.   The manufacturing method according to claim 1, wherein a one-component curable resin containing a foaming agent is applied before performing the first step, and the one-component curable resin is applied to the second step. While maintaining the fluidity of the resin inside, the intermediate layer is provided by curing until the fluidity of the surface layer of the resin disappears, curing to the inside of the resin and foaming in the third step. The manufacturing method of the steel plate reinforcement material for motor vehicles characterized by these.   The manufacturing method according to claim 4, wherein a mixed resin of an epoxy resin and a urethane resin is used as the one-component curable resin containing a foaming agent.   The manufacturing method according to claim 4 or 5, wherein the discharge pipe is rotated when the one-component curable resin, which is the raw material of the intermediate layer, is applied to the automotive steel plate. Production method.   The manufacturing method of any one of Claims 1-6 WHEREIN: An epoxy resin is used as said resin used as the said steel plate reinforcing material for motor vehicles, The manufacturing method of the steel plate reinforcing material for motor vehicles characterized by the above-mentioned.   In the manufacturing method of any one of Claims 1-7, when applying the said one-component curable resin which is a raw material of the said steel plate reinforcing material for motor vehicles to a steel plate for motor vehicles, rotating a discharge pipe is carried out. A method for producing a steel plate reinforcing material for automobiles, which is characterized.

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