JP2010260262A - Method of manufacturing laminated member having resin foam disposed in-between - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To fill the clearance with a resin foam easily responding to variation even if there is variation in the clearance between substrates 1, 2 in a laminated member obtained by disposing the resin foam between the substrates at least one of which is a resin substrate. <P>SOLUTION: The laminated structure body 10 of a resin foam body layer 11 obtained by previously foaming with a non-foamed resin layer 12 containing a laminated foaming agent therein is disposed between resin substrates 1, 2. Afterward, the non-formed resin layer 12 is heated at the temperature below the deformation of the resin substrates 1, 2 to foam the non-foamed resin layer and produces a post-foaming layer 13, and the clearance between the substrates 1, 2 is filled up with the resin foam body layer 11 and the post-foaming layer 13. Preferably, a mastic adhesive foamed and cured in a sheet shape is used for the resin foam body layer 11. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a laminated member having a resin foam interposed therebetween, and in particular, to manufacture a laminated member in which a resin foam is arranged between substrates, at least one of which is a resin substrate. It relates to a suitable manufacturing method.

  A member that requires a certain level of cushioning as well as a required strength, such as a vehicle outer plate (hood, door, roof, etc.), generally uses a resin foam as a cushioning material between two thin metal plates. Arranged configuration is taken. By arranging the resin foam in between, the weight of the member can be reduced. In manufacturing such a laminated member, as described in Patent Document 1, an adhesive sheet containing a curing agent and a foaming agent is attached to a metal plate, and electrodeposition coating is applied to the metal plate. When the electrodeposition coating film is heated and baked, a technique is employed in which the adhesive sheet is foam-cured by using heat at the time of baking. As an example of an adhesive sheet used for such applications, a mastic adhesive as described in Patent Document 2 is known, and by using this type of mastic adhesive, the tension rigidity of the laminated member is improved. be able to.

  Further, Patent Document 3 discloses that a laminated member having a cushioning property is obtained by integrally bonding a pair of thermoplastic resin members having a clearance variation between bonding surfaces with a resin foam of an adhesive thermoplastic material. Are listed.

JP 61-41537 A JP 2000-96026 A JP 2001-162709 A

  The mastic adhesive that has been conventionally used to manufacture a laminated member having the resin foam disposed therebetween is developed on the assumption that it is used between two thin metal sheets. Many of them are foam-cured at a temperature of about 170 ° C., which is the temperature at the time of baking the electrodeposition coating applied to the film. In recent years, there has been a movement to use both or either of the two-layered outer plates as resin substrates for the purpose of improving fuel efficiency by further reducing the weight of the vehicle, and SMC and polypropylene made of unsaturated polyester resin. A resin based on polyamide or a resin based on polyamide has been used as a resin substrate for an outer plate.

  However, the resin material is inferior in heat resistance as compared with the metal plate, and if the resin material is passed through an electrodeposition baking furnace having a temperature of about 170 ° C., the resin base material may be deformed. Therefore, when a resin base material is used as the outer plate portion, a manufacturing method is adopted in which a conventional mastic adhesive having a foaming temperature of about 170 ° C. is used, and the mastic adhesive is foamed and cured simultaneously with electrodeposition baking. This is a problem that cannot be solved.

  A mastic adhesive that has been foam-cured into a sheet in advance can be fastened to a resin substrate with an adhesive or adhesive, but the mastic should match the change in clearance between the two substrates. It is difficult to foam and cure the adhesive in advance, and even if possible, it is necessary to prepare several types of molded mastic materials according to the size and shape of the clearance between the two outer plates. Must not. It may be possible to match the height of the molded mastic material that has been foam-cured in advance to the thickness of the widest clearance area, but high pressure is required to crush the mastic material in areas where the clearance is narrow, which constitutes the outer plate Assembling of the resin base material becomes extremely difficult, and in some cases, a desired external shape may not be obtained.

  As described in Patent Document 3, a technique is known in which a pair of thermoplastic resin members are integrally bonded with a resin foam of an adhesive thermoplastic material. When a base material is used, as described above, the clearance between the two base materials varies widely, so that the entire clearance portion is filled with a single foamable material so as to have a desired buffering property. Therefore, it is necessary to prepare a foamable material having various foaming ratios and capable of foaming the foaming agent at a temperature lower than the deformation temperature of the resin material constituting the resin base material.

  The present invention has been made in view of the above circumstances, and in a laminated member in which a resin foam is disposed between substrates, at least one of which is a resin substrate, the clearance between the substrates is reduced. It is an object of the present invention to disclose a method for manufacturing a laminated member that can easily be filled with a resin foam even when there is variation, so that it can be filled with a resin foam.

  The present invention relates to a method for manufacturing a laminated member in which a resin foam is disposed between substrates, at least one of which is a resin substrate, the resin foam layer formed by foaming in advance and the resin foam layer A step of disposing a laminated structure with a non-foamed resin layer containing a foaming agent laminated on at least one side between the substrates, and a step of heating the non-foamed resin layer to foam the non-foamed resin layer , Including.

  In the production method according to the present invention, a laminated structure of a resin foam layer previously foamed and an unfoamed resin layer containing a foaming agent laminated on at least one surface of the resin foam layer is disposed between the substrates. To do. In this case, the resin foam layer previously foamed fills a region that can be grasped as an approximately equal thickness in the clearance between the two substrates. Therefore, the resin foam layer may be a foam sheet having a predetermined thickness and is easy to manufacture. Although not limited, preferably, the resin foam layer is a conventional sheet-like mastic adhesive. Thereby, big tension rigidity can be provided to the laminated member after manufacture. The unfoamed resin layer fills the uneven portion on the back surface side of the base material formed on one side or both sides of the region that can be grasped as the same thickness in the clearance between the two base materials.

  When the laminated structure of the resin foam layer and the unfoamed resin layer is disposed between two substrates, the laminated structure has substantially the same thickness as the resin foam layer, After placing between the base materials, there is no problem in assembling the two base materials together. After the assembly, at least the unfoamed resin layer is heated to foam and cure the unfoamed resin layer. The unfoamed resin layer expands due to foaming and fills the concavo-convex portion on the back side of the substrate. Therefore, even if there is a variation in the clearance between the two substrates at the place where the laminated structure is arranged, all the clearance is filled with the foam material by using the laminated structure of one kind of thickness. be able to. Thereby, desired rigidity and buffering properties are imparted to the laminated member after foam molding.

  In the manufacturing method by this invention, it is preferable to use the foaming agent whose foaming temperature is below the temperature which the said resin base material deform | transforms as a foaming agent contained in the said non-foamed resin layer. Thereby, a required foaming process can be performed, without producing a deformation | transformation in a resin base material. The temperature at which the resin base material deforms is usually about 120 ° C. or less, although it depends on the type of resin. Therefore, the foaming agent is preferably one that foams at a temperature of about 120 ° C. or less, and an example of such a foaming agent is hydrous sodium silicate.

  In the production method of the present invention, even when a mastic adhesive that requires a foaming temperature of about 170 ° C. is used, a mastic adhesive that has already been foam-cured into a sheet is used. This temperature does not require a high temperature of 170 ° C. Therefore, when forming a coating film necessary for the resin base material, the non-foamed resin layer can be obtained by using a paint having a baking temperature not higher than a temperature at which the resin base material is not deformed (for example, about 90 to 120 ° C.). The heating can be performed by the heat at the time of baking of the paint applied to the resin base material. Thereby, simplification of processing is achieved.

  In this invention, there is no restriction | limiting in particular in the resin material which forms a resin foam layer, Foams, such as PVC, urethane, a synthetic rubber, are used suitably. One type of foam of these materials may be sufficient, and the foam of what mixed them may be sufficient. The elastic modulus of the resin foam layer is not particularly limited, but when the laminated member according to the present invention is a vehicle outer plate (a hood, a door, a roof, etc.), it is preferably in the range of 100 to 400 kPa.

  Although there is no restriction | limiting in particular also in the resin material which forms an unfoamed resin layer, It may be an elastic component which is PVC, urethane, synthetic rubber etc. similarly to the resin foam layer. One kind of these materials may be sufficient, and what mixed them may be sufficient. Preferably, the same resin material is used for the resin foam layer and the unfoamed resin layer. Thereby, the integrity between the layers is improved. Although the foaming agent contained in the unfoamed resin layer has been described above, the foaming agent is preferably added at 0.1 to 1% by weight with respect to the resin component (elastic component), and the expansion ratio is 2 to 4 times. A post-foamed resin layer is obtained. When the foaming agent is 0.1% by weight or less, sufficient foaming of the unfoamed resin layer cannot be obtained, and the variation in clearance may not be filled with the foaming material as desired. If the foaming agent exceeds 1% by weight, the expansion ratio becomes too large, the rigidity of the surface of the outer plate is insufficient, and there is a possibility that it is likely to be deformed by an external force.

  In the method for manufacturing a laminated member having a resin foam interposed therebetween according to the present invention, the two opposing substrates may be both resin substrates, and only one of them is a resin substrate. Also good. In any case, the resin material of the resin base material is not particularly limited, but is preferably a thermoplastic resin for reasons such as moldability, and is preferably SMC, polypropylene resin, or polyamide made of unsaturated polyester resin. Examples of such resins are listed below. When one is a resin substrate, the other may be a metal plate or an appropriate inorganic plate.

  Furthermore, the unfoamed resin layer may be laminated on both sides of the resin foam layer, or may be laminated only on one side. Either one is selected according to the purpose of use of the laminated member to be manufactured. When only one is a resin substrate, the unfoamed resin layer is at least laminated on the surface of the resin foam layer on the side facing the resin substrate. In any case, the unfoamed resin layer can be formed by applying to the surface of the resin foam layer.

  Further, the laminated structure may be disposed so as to cover the entire surface of the substrate, or may be partially disposed at an appropriate position of the substrate. When placing the laminated structure on the substrate, place an appropriate adhesive between the substrate and the laminated structure to prevent free movement of the laminated structure until foaming of the unfoamed resin layer is complete. It is preferable to keep it. An appropriate pressure-sensitive adhesive may be added to the unfoamed resin layer so as to have adhesiveness after firing.

  According to the manufacturing method of the present invention, even when a clearance having a variation is formed between two substrates, at least one of which is a resin substrate, even if it is a laminated member, it can easily cope with the variation in the clearance. A laminated member filled therewith with a resin foam can be obtained.

The figure which shows an example of the manufacturing method of the laminated member which has arrange | positioned the resin foam by this invention in between. The figure which shows the other example of the manufacturing method of the laminated member which has arrange | positioned the resin foam by this invention. The figure which shows the further another example of the manufacturing method of the laminated member which has arrange | positioned the resin foam by this invention.

Embodiments of the present invention will be described below.
In the example shown in FIG. 1, the laminated structure 10 according to the present invention is disposed between resin substrates 1 and 2. Either one may be a base material made of another material such as a metal plate. A coating film 3 is formed on the surface of the resin substrate 2. As shown to Fig.1 (a), the laminated structure 10 is the foamed resin layer 11 formed beforehand, and the non-foamed resin layer 12 containing the foaming agent formed by drying after application | coating on both surfaces , 12. The thickness of the laminated structure 10 is smaller than the clearance between the two resin substrates 1 and 2 by a distance p. Adhesive tapes 4 and 4 containing an adhesive made of acrylic or rubber are preferably attached to both surfaces of the laminated structure 10, and the lower surface of the laminated structure 10 is placed on the lower resin by the adhesive tape 4. Fixed to the substrate 1.

In the laminated structure 10, the resin foam layer 11 is obtained by foaming and curing a mastic adhesive in a sheet shape at a temperature of about 170 ° C., for example. The unfoamed resin layer 12 is obtained by, for example, dissolving nitrile rubber with a solvent and adding an appropriate amount of foaming agent (about 0.1 to 1% by weight) therein. Examples of the foaming agent include hydrous sodium silicate ( For example, sodium metasilicate pentahydrate _{Na 2 SiO 3 · 5H 2 O} ) and the like. The hydrous sodium silicate foams when moisture in the hydrous sodium silicate is removed at a temperature of about 90 ° C. to 120 ° C. to form a hollow glass sphere.

  As shown in FIG. 1A, after the laminated structure 10 is disposed between the resin bases 1 and 2, the coating film 3 is formed on the surface of the resin base 2. As the coating material for the coating film 3, a type of coating material that is baked at a temperature equal to or lower than the temperature at which the resin base materials 1 and 2 are deformed is used. The coating film 3 is baked in the state shown in FIG. Baking is performed at a temperature equal to or lower than the temperature at which the resin base materials 1 and 2 are deformed by heat. The unfoamed resin layers 12 and 12 are foamed by heat at the time of firing, and form foamed layers 13 and 13 having elasticity. Due to the expansion of the volume, the thickness of the laminated structure 10 becomes thick, and the upper surface thereof is in close contact with the back surface of the upper resin base material 2 via the adhesive tape 4 as shown in FIG. .

  As described above, many portions of the clearance between the resin bases 1 and 2 are filled with the resin foam layer 11 that is previously foamed, and the portion of the distance p described above is the unfoamed resin layer 12. , 12 are filled by foaming at a foaming ratio of about 2 to 4 times, for example. In the example shown in FIG. 1, there is no variation in the clearance between the two resin substrates 1 and 2, and the gap is a uniform gap of distance p. Even if there is variation in the clearance between the two, all the gaps can be filled with the foamed material depending on the behavior of the unfoamed resin layers 12 and 12 during foaming.

  In the example shown in FIG. 2 (a), the laminated structure 10a is composed of a resin foam layer 11 previously foamed and an unfoamed resin layer 12 containing a foaming agent formed only on one surface thereof. This is different from that shown in FIG. When the distance (gap) p described above is small, the gap p can be filled by foaming of the unfoamed resin layer 12, as shown in FIG. It is.

  By increasing the expansion ratio of the unfoamed resin layer 12, a larger gap p can be filled by foaming of the unfoamed resin layer 12. However, when the expansion ratio is increased, the density of the foam layer is decreased and the foam layer is easily deformed. In the case of a member that needs to have a cushioning property but requires a certain degree of rigidity, such as an outer plate part of an automobile, if the foaming ratio is increased unnecessarily, foaming formed by foaming of the unfoamed resin layer 12 Due to the deformation of the material, the resin base materials 1 and 2 are easily deformed, which is not preferable. Therefore, as described above, the unfoamed resin layers 12 and 12 are preferably foamed at a foaming ratio of about 2 to 4 times, and in view of this, either the laminated structure 10 or the laminated structure 10a. Select. Alternatively, any one of them is selectively arranged depending on the difference in the width of the location and the clearance at the location.

  The example of FIG. 3 is a partial view in the case where the laminated member is an automobile door, where one base material is the inner 1a and the other base material is the outer plate 2a. And the coating film 3 is formed in the surface of the outer plate | board 2a. The outer plate 2a has a convex shape with the center swelled as a whole, and the inner 1a is a flat plate. In the illustrated example, the laminated structure 10 of the right and left ends and the central portion is disposed at an appropriate position of the inner 1a, and the outer plate 2a is laminated thereon, and the side edge 2b of the outer plate 2a is bent to be inner. It is integrated with 1a. As shown in FIG. 3 (a), the laminated structures 10 and 10 located on both sides of the inner 1a in an integrated state are substantially in contact with the back surface of the outer plate 2a and are located in the center. A gap of distance pa is formed between 10 and the back surface of the outer plate 2.

  The coating film 3 formed on the surface of the outer plate 2a is baked on the laminate in the state shown in FIG. Due to the heat at that time, the unfoamed resin layer 12 of the laminated structure 10 tends to expand due to foaming. However, since the laminated structures 10 and 10 positioned on both sides of the inner 1a are restrained by the outer plate 2a, they cannot be foamed greatly. However, the laminated structure 10 located in the center is foamed as needed, and the gap (distance) pa between the back surface of the outer plate 2a is filled with the foamed material. In this way, an automobile door having the required strength and shock-absorbing properties can be obtained. Of course, the laminated structure 10 may be disposed over the entire surface of the inner 1a, and the foaming process may be performed in the same manner. Further, the foaming treatment can be performed by applying heat to the unfoamed resin layer 12 of the laminated structure 10 by an appropriate heating means, not by heat at the time of baking the coating film. In that case, you may make it heat the unfoamed resin layer 12 in the state which pinched | interposed the inner 1a and the outer plate | board 2a with the heating hotplate.

The present invention will be described with reference to examples and comparative examples.
[Example]
A commercially available mastic adhesive (# 586 made by Iida Sangyo) was foam-cured into a sheet having a thickness of 2 mm at 170 ° C. for 20 minutes in the same manner as in the electrodeposition baking furnace. Thereafter, the nitrile rubber was dissolved in a solvent (toluene), 0.2 wt% of sodium metasilicate was added thereto, and an unfoamed resin liquid containing a foaming agent was mixed on one side of the sheet-like mastic adhesive with a thickness of 1 mm. The laminated structure was obtained by uniformly applying and drying. A 0.4 mm thick acrylic foam double-sided tape was bonded to both sides of the laminated structure to obtain a test piece.

Using the test piece, the hardness, rubber properties, adhesiveness, and clearance filling property were tested as follows. The results are shown in Table 1.
(Test items)
1. Hardness Test pieces were cut into 50 mm squares and overlapped to a height of 12 mm or more, and the hardness was measured with a hardness tester (ASTM D412 Die A type).

2. Rubber physical properties The test piece was punched into a dumbbell shape (JIS K 6251 No. 2 dumbbell), the minimum thickness of the parallel part of the test piece was measured, and a marked line with a distance of 20 mm was written at the center. This was attached to an Instron type tensile tester, pulled at a tensile speed of 50 mm / min, and measured for tensile strength, elastic modulus, and elongation.

3. Adhesion The test piece is cut to a size of 25 mm x 25 mm, an electrodeposited Al plate with a size of 100 x 25 x 2.0 (thickness) mm is attached to one side, and the same electrodeposition is performed with the opposite direction on the opposite side. An Al plate was pasted to prepare a shear adhesion test piece. The test piece was allowed to stand at room temperature for 24 hours and then deteriorated under the following conditions, and then the shear adhesive strength (tensile speed: 50 mm / min) was measured.
(1) During normal operation
(2) After heat deterioration (120 ° C x 20 days)
(3) After hot water deterioration (40 ° C hot water immersion x 20 days)
(4) After wet heat deterioration (50 ° C, 95% RH x 20 days)

4). Clearance filling property The test piece was cut to a size of 25 mm x 25 mm and attached to the center of an electrodeposited Al plate of 100 x 25 x 2.0 (thickness) mm. On top of that, an electrodeposited Al plate having the same shape was installed using a spacer so that the clearance was 3 mm, and the ends were fixed with clips. It was heated in an oven heating furnace at 90 ° C. for 20 minutes, and it was confirmed whether the clearance was filled by foaming of unfoamed resin.

[Comparative Example 1]
A commercially available mastic adhesive (# 586 made by Iida Sangyo) was foam-cured into a sheet having a thickness of 2 mm at 170 ° C. for 20 minutes in the same manner as in the electrodeposition baking furnace. A 0.4 mm thick acrylic foam double-sided tape was bonded to both sides of the laminated structure to obtain a test piece. Using the test piece, the hardness, rubber physical properties, adhesiveness, and clearance filling property were tested in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 2]
A test piece was obtained by bonding a 0.4 mm thick acrylic foam double-sided tape to both sides of a sheet-like 3 mm thick EPDM foam. Using the test piece, the hardness, rubber physical properties, adhesiveness, and clearance filling property were tested in the same manner as in Example 1. The results are shown in Table 1.

  In Table 1, the values of the judgment criteria in hardness, rubber physical properties, and adhesiveness are standard values required for the mastic adhesive when the metal plates are bonded to each other using a commercially available mastic adhesive, and exceed this value. If it is, it can be put to practical use, and it was determined to be an acceptable product (◯). Moreover, clearance filling property was set as the acceptable product ((circle)) when there was no clearance, and the rejection product (x) when there was a clearance.

[Evaluation]
Example product (product structure of the present invention) (a laminated structure of a previously foamed resin foam layer and a non-foamed resin layer containing a foaming agent laminated on at least one surface of the resin foam layer) As a resin foam to be placed between the base materials constituting the laminated member, the physical properties equivalent to those of the commercially available mastic adhesive shown in Comparative Example 1 are passed in the measurement items of hardness, rubber physical properties, and adhesiveness. It is shown that the value can be retained. And since it can satisfy clearance filling property, maintaining the physical property value equivalent to a commercially available mastic adhesive, the laminated member manufactured according to the manufacturing method by this invention using the Example goods which are this invention products Shows a high effectiveness in practical use.

  Comparative Example 2 using the EPDM foam is inferior in rubber physical properties and adhesiveness as compared with the mastic adhesive (Comparative Example 2), and naturally it cannot satisfy the clearance filling property.

1, 2 ... resin base material,
3 ... Paint,
10, 10a ... laminated structure,
11 ... Resin foam layer previously foamed,
12 ... an unfoamed resin layer containing a foaming agent,
4 ... Adhesive tape containing adhesive,
13 A rear foam layer having elasticity.

Claims (4)

A method for producing a laminated member in which a resin foam is disposed between substrates, at least one of which is a resin substrate,
Arranging a laminated structure of a resin foam layer formed in advance and an unfoamed resin layer containing a foaming agent laminated on at least one surface of the resin foam layer between the substrates;
Heating the unfoamed resin layer to foam the unfoamed resin layer;
The manufacturing method of the laminated member which has arrange | positioned the resin foam characterized by including in between.   2. The resin foam according to claim 1, wherein a foaming agent having a foaming temperature equal to or lower than a temperature at which the resin base material is deformed is used as the foaming agent contained in the unfoamed resin layer. A method for manufacturing a laminated member.   The method for producing a laminated member having a resin foam interposed therebetween according to claim 1 or 2, wherein the unfoamed resin layer is heated by heat at the time of baking of the paint applied to the resin base material. .   The laminated member having the resin foam according to any one of claims 1 to 3, wherein a mastic adhesive that is foam-cured and cured in a sheet shape is used as the resin foam layer that is foamed in advance. Manufacturing method.

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