JPH04158009A - Method of filling foam body - Google Patents

Abstract

PURPOSE:To improve the rigid forces of a vehicle body, and prevent the occurrence of noisy sound due to a foam body by inserting a bag previously formed by a thermoplastic adhesive agent into the inner space of a structural body into which a foam body is filled, and injecting a foam material into the bag and then foaming it therein, and further heating and softening the bag. CONSTITUTION:A bag 3 is formed into a bottomed cylindrical shape by a thermoplastic adhesive agent, and it has an opening 4 in its upper part. At first, the bag 3 is inserted into the hole of a pillar 1, and when a foam material is injected therein from the opening 4 by means of a discharging gun 5 and then left herein, the foam material foams in the bag 3 and expands corresponding to the shape of a pillar inner surface as a structural body l. Next, when the bag 3 is heated at the temperature slightly higher than the softening temperature of the bag constitutional thermoplastic adhesive agent, the bag 3 softens in the form of being in close contact with the pillar inner surface, so that when cooled to room temperature thereafter, it adheres firmly thereto. Accordingly, the foam body 6 and structural body 1 are adhered to each other fixedly, thereby improving the rigid forces of the structural body 1, and preventing the occurrence of noisy sound due to the vibration of the foam body 6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for filling a foam, and particularly to a method for encapsulating a foam in a structure such as an automobile pillar for vibration damping, sound insulation, and heat insulation.

(Prior art) The interior spaces of automobile body structures such as pillars, roofs, sills, and wheel houses are filled with foam for the purpose of reducing noise, absorbing vibrations, and insulating the interior and exterior of the vehicle.
is being carried out.

In the conventional foam filling method, a bag corresponding to the internal shape of the structure to be filled is inserted into the structure, a liquid foaming raw material and a foaming agent are injected into the bag, and then foaming is performed by heating or a catalyst. The idea was to foam the raw materials.

For example, the foam filling method disclosed in JP-A No. 61-205.109 uses a bag made of a rubber sheet or a synthetic resin sheet such as polyvinyl chloride, polyethylene, or polypropylene, and uses pillars, etc. A crosspiece is formed in the structure, and a bag into which foaming raw materials and a foaming agent are injected together with a catalyst is placed on the crosspiece to maintain the shape and posture of the bag.

(Problem to be Solved by the Invention) However, according to the conventional foam filling method, the bag was made of rubber or synthetic resin such as polyethylene. There was a problem in that it did not adhere to the inner surface of the body and did not contribute much to the rigidity of the vehicle body. Further, there has been a problem in that the bag body and the inner surface of the structure come into sliding contact due to vibrations when the car is running, which causes abnormal noise.

The present invention has been made in view of the problems of the prior art, and aims to improve the rigidity of a car body by filling it with foam, and to prevent the occurrence of abnormal noise due to the foam. purpose.

(Means for Solving the Problems) A first invention for achieving the above object includes inserting a bag formed in advance with a thermoplastic adhesive into the internal space of a structure to be filled with a foam, This foam filling method is characterized by injecting a foaming raw material into the bag and foaming the foaming raw material, and then softening the bag by heating the bag.

Further, a second invention for achieving the above object is 1.
A bag formed in advance with thermoplastic adhesive is inserted into the internal space of the structure to be filled with the foam, and a foaming raw material 1 that foams by exothermic reaction with the catalyst is injected into the bag together with the catalyst. This is a foam filling method characterized by foaming and softening the bag.

(Operation) According to the first invention configured as described above, when the foam is inserted into the internal space of the structure to be filled and the foaming raw material is injected into the bag and the foaming raw material is foamed, the structure The bag expands so that the inner surface of the bag and the bag body come into close contact with each other. Next, when the bag is heated to soften it, the bag and the inner surface of the structure are bonded together because the bag is molded with a thermoplastic adhesive.

In a second invention, the foam is inserted into the internal space of a structure to be filled, and a foaming raw material that generates foam by an exothermic reaction with a catalyst is injected into the bag together with the catalyst to cause foaming.
The inner surface of the structure and the bag are expanded so as to come into close contact with each other. At the same time, the bag softens due to the heat generated by this foaming reaction.
This causes the bag body and the inner surface of the structure to adhere to each other.

Therefore, the foam and the structure are firmly bonded to each other, the rigidity of the structure is improved, and it is also possible to prevent the generation of abnormal noise due to vibration of the foam.

(Example) First, an example of the first invention will be described based on the drawings.

FIG. 1 is a perspective view showing an embodiment of the first invention, FIG. 2 is a sectional view of a structure filled with foam of the same embodiment, and FIG. 3 is a process diagram showing the same embodiment. A case will be explained in which the foam is filled into the pillars of an automobile.

A hole 2 is bored above the cabin 1 (structure) of the automobile body according to this embodiment, and a bag body 3 according to this embodiment
is inserted through this hole 2. It is preferable that this hole be used in common as a hole for assembling the parts, and it is preferable that the hole be drilled in a selected area that will be hidden by interior parts such as a garnish when the filling operation is completed. Bag body 3 according to this embodiment
is formed into a bottomed cylindrical shape using thermoplastic adhesive, and has an opening 4 at the top for injecting the foaming raw material and foaming agent. Further, it is formed into an appropriate size depending on the volume of the structure to be filled. Note that the opening 4 for injecting the foaming raw material as in this embodiment does not necessarily need to be provided at the top of one bag 3, but may be provided on the side surface depending on the structure to be inserted or the hole position of the structure. You can also do that.

Generally, the thermoplastic adhesive constituting the bag 3 according to this embodiment is chemically stable, so it is less likely to decompose during storage and has excellent durability. In addition, since it is already a polymer when bonded, it has excellent workability, and it also has the advantage that the composition of the polymer can be changed by copolymerization or blending depending on the application, making it compatible with a wide range of adherends. are doing.

The thermoplastic adhesive that can be applied to the bag body 3 according to this embodiment is a copolymer of ethylene and vinyl acetate, or a copolymer of ethylene and vinyl acetate, or a copolymer of this with an unsaturated acid such as acrylic acid, methacrylic acid, or maleic acid. Alternatively, polyamide adhesives such as dimer acid polyamide made from unsaturated fatty acid dimer and ethylene diamine, co-condensation polyester adhesives of glycol, terephthalic acid, cepacic acid, etc., and isocyanate and alcohol are used in excess of alcohol. Examples include polyurethane adhesives that have been reacted with.

Using such a thermoplastic adhesive, the bag 3 is previously formed by blow molding or the like according to the shape of the structure 1 to be filled.

On the other hand, the foaming raw material according to this embodiment uses a resin capable of bead foaming, such as polystyrene, polyethylene, polypropylene, etc., and can be foamed by applying a certain pressure and heating steam. Moreover, it is also possible to mold polyurethane foam by mixing a polyisocyanate liquid and a mixed liquid of a polyol, a blowing agent, a catalyst, a surfactant, and the like.

Next, a process of filling a pillar of an automobile with a foam using the filling method of this embodiment will be described.

First, the bag 3 is inserted into the hole 2 of the pillar 1 with the opening 4 facing upward and the bottom facing downward, and the nozzle 5a of the gun 5 that discharges the foaming material from the opening 4 of the bag 3 is inserted. Then, the foaming raw material is injected by the discharge gun 5 in an amount calculated from the volume of the pillar 1. When left in this state for a predetermined period of time, the foaming raw material foams within the bag 3 and is engraved in accordance with the shape of the inner surface of the pillar that is the structure 1 (see FIG. 2).

Next, either transport the car body to a drying device or
is heated locally to a temperature slightly higher than the softening temperature of the thermoplastic adhesive constituting the bag body 3. As a result, the bag body 3 made of thermoplastic adhesive softens while in close contact with the inner surface of the pillar, so that when it is subsequently cooled to room temperature, the bag body 3 and the inner surface of the pillar 1 are firmly bonded.

It should be noted that the set temperature for the main heating step must be determined not only by the softening temperature of the thermoplastic adhesive mentioned above, but also by taking into account the influence on other parts assembled in the automobile.

As described above, according to the filling method of this embodiment, the foam 6 and the structure 1 are firmly bonded, the rigidity of the structure 1 is improved, and the noise caused by the vibration of the foam 6 is reduced. Occurrence can also be prevented.

Next, an embodiment of the second invention will be described based on the drawings.

FIG. 4 is a perspective view showing an embodiment of the second invention, FIG. 5 is a longitudinal sectional view showing a bag body of the same embodiment, and FIG. 6 is a process diagram showing the steps of the same embodiment. In this embodiment, similarly to the embodiment according to the first invention described above, a case will be described in which the pillar of an automobile is filled with a foam.

The present invention attempts to utilize the reaction heat generated in the foaming reaction when softening the bag after foaming the foaming raw material.

The foam according to this example mainly consists of a polyol that is a mixture of three types: a liquid containing isocyanate as its main component, a blowing agent such as Freon, a catalyst such as a tertiary amine or a salt removed, and a silicone surfactant. It is possible to use a foam made by mixing a liquid with a liquid. When filling this foam, as shown in FIG.
．． 10, the two solutions are mixed by a discharge gun 5, and the foaming stock solution is injected into the bag body 3 through a nozzle 5a in an amount calculated from the volume of the pillar 1.

Furthermore, as shown in FIG. 5, the bag 3 according to this embodiment is made by blow molding a sheet with a two-layer structure in which the outer surface of a heat-resistant film 7 made of polyurethane or the like is coated with a thermoplastic adhesive 8. It is molded into a cylindrical shape. This heat-resistant urethane layer 7 is intended to sufficiently maintain its shape even if high-temperature heat is transferred to the bag body 3 during the foaming reaction. Therefore, a material may be selected in consideration of heat resistance depending on the exothermic temperature of the foaming reaction. The thermoplastic adhesive 8 coated on the outer surface of the heat-resistant urethane layer 7 may be the same adhesive as in the embodiment described above.

In this embodiment configured in this way, first, the bag body 3
The bag is inserted into the hole 2 of the pillar 1 with the opening 4 facing upward and the bottom facing downward, and the nozzle 5a of the discharge gun 5 is inserted into the opening 4 of the bag 3. Pillar 1 while mixing the foaming raw materials, foaming agent, catalyst, etc.
Inject only the amount calculated from the volume. When left in this state for a predetermined period of time, the foaming raw material foams inside the bag 3 and forms the structure 1.
The engraving is done in accordance with the shape of the inner surface of the pillar.

At the same time, since this foaming reaction is an exothermic reaction, the reaction heat is transmitted through the urethane layer 7 of the bag, softening the thermoplastic adhesive 8 coated on the outer surface of the bag, and then cooling the bag to room temperature. This results in strong adhesion between the inner surface of the pillar and the inner surface of the pillar.

As described above, according to the filling method of this example, the foam and the structure are firmly bonded, the rigidity of the structure is improved, and the occurrence of abnormal noise due to vibration of the foam is also prevented. be able to.

Note that the present invention is not limited to the above-described embodiments, and can be modified in various ways without departing from the gist of the present invention.

(Effects of the Invention) As described above, according to the foam filling method of the present invention,
Filling with foam can improve the rigidity of the vehicle body, and can also prevent the foam from producing abnormal noise.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the first invention, FIG. 2 is a sectional view of a structure filled with foam of the same embodiment, and FIG. 3 is a process diagram showing the same embodiment. , FIG. 4 is a perspective view showing an embodiment of the second invention, FIG. 5 is a longitudinal sectional view showing a bag body of the same embodiment, and FIG. 6 is a process diagram showing the same embodiment. 1... Pillar (structure), 2... Hole, 3... Bag, 6... Foam. Patent applicant Nissan Motor Co., Ltd. agent Patent attorney Mikio Heda (and 1 other person) Figure 3 Figure 6

Claims (2)

[Claims] (1) After inserting a bag previously formed with thermoplastic adhesive into the internal space of the structure to be filled with foam, and injecting foaming raw material into the bag to foam the foaming raw material, A method for filling a foam, the method comprising softening the bag by heating the bag. (2) A bag previously formed with thermoplastic adhesive is inserted into the internal space of the structure to be filled with foam, and a foaming material that foams by exothermic reaction with the catalyst is injected into the bag together with the catalyst. A method for filling a foam, which comprises softening the bag while foaming the bag.