JP6096532B2 - In-mold adhesion molding method between different polymers and method for producing waterproof product - Google Patents

Description

  The present invention relates to a technique for adhering different polymers through a primer.

  Many devices and structures, including mobile phones and smart meters, dislike the contact and mixing of liquids including water, such as batteries, antennas, and electronic circuits. It has become. In the Great East Japan Earthquake, since many automobiles were flooded, the control system that should be called the heart of the car became unusable, and many cars were scrapped. The complete prevention function is also an important element that guarantees regional infrastructure.

Taking a cellular phone as an example, silicon resin or the like is adhered or fastened to the inside of an exterior part such as a battery cover in order to provide this complete waterproof function.
In a structure such as an O-ring, handling at the time of removal becomes difficult, and therefore, in many cases, an exterior part and silicon resin or the like are usually bonded.

In that case, the method of applying and bonding the silicon resin main body and the adhesive separately to a predetermined position of the exterior component (adhesion outside the mold) requires enormous labor.
Therefore, a method (selective bonding) is employed in which a resin in which an adhesive component is contained and dissolved in a silicon resin is used, and the resin is molded in a predetermined position of the exterior part in a mold.

In this selective bonding, flow unevenness during molding is unavoidable, and if the flow rate during molding is excessive, the silicon resin containing the adhesive component leaks from a predetermined position and adheres to the exterior component surface.
Since it contains an adhesive component, it currently requires a great deal of labor to remove these burrs and defects (see Non-Patent Document 1). Also, if the flow rate during molding is too small, adhesion failure will occur, resulting in failure in lot units, which will be a major production problem.
Quality control of waterproof packing and waterproof rubber Internet URL: http://www.kyowakg.com/products/bosui/kanagata.html Search date: February 18, 2013

  The present invention has been devised to solve the above-described conventional problems, and it is difficult to cause burrs or poor adhesion, and an adhesion technique between different polymers that is easy to remove even if burrs are generated. It is intended to provide.

In order to achieve the above object, in the in-mold adhesive molding method between different types of polymers according to claim 1, the surface of an object to be joined made of the first polymer is insert-clamped into a bonded mold. A step of injecting a primer containing or dissolving an adhesive component into the recess from the gate communicating with the recess of the mold, and forming an adhesion preparation region on the surface of the object to be joined; Injecting the melted second polymer to fill the recess with the second polymer, and preparing the adhesion of the surface of the first polymer joined object from the mold after the second polymer is solidified And a step of removing the second polymer bonded to the region .

Mold adhesion molding method between heterogeneous polymer according to claim 2, wherein the method of claim 1 assumes, further advance fine in a region corresponding to at least the adhesive preparation region definitive on the surface of the object to be bonded recess It is characterized in that a process for forming a large number of the films is provided.

  The in-mold adhesive molding method between different types of polymers described in claim 3 is based on the method of claim 2, and the mold for forming the object to be joined is irradiated with an ultrashort pulse laser to obtain a large number. The concave portion of the article to be joined is formed by transferring the concave portion.

The method for manufacturing a waterproof product according to claim 4 includes a step of inserting and clamping a surface of an object to be joined made of the first polymer to a die for molding a joint, and a gate communicating with the concave portion of the die. Then, a step of injecting a primer containing or dissolving an adhesive component into the recess to form an adhesion preparation region on the surface of the bonded product, and a state in which the second polymer for packing formation is melted from the gate And filling the second polymer into the recess, and after the second polymer is solidified, the second polymer joined from the mold to the adhesion preparation region on the surface of the first polymer joined object. And 2) removing the polymer.

This technique (in-mold adhesion) solves the problems of the out-of-mold adhesion method and the selective adhesion method.
First, an adhesive component is not included in the polymer on the bonding side such as silicon resin. Specifically, a primer is applied to a predetermined position of a heterogeneous polymer constituting a product in a mold, and only a portion constituting an adhesion portion of the product is set in an adhesion ready state.
Next, the different polymer to be bonded / bonded is molded in the mold, and bonded / bonded in the mold with the different polymer constituting the product ready for bonding.

Since all processes for molding the final product from the stage of preparing the adhesion preparation state are performed in the mold, there is no need for adhesion / joining outside the mold.
In the mold, since the different polymer to be bonded / bonded is bonded / bonded only to the different polymer constituting the product in the ready state for bonding, no burr is generated in principle.
In addition, by managing the excess and deficiency of different types of polymers to be bonded and joined by the control system of the molding apparatus, product defects due to insufficient flow rate do not occur.

  Furthermore, the above-mentioned in-mold adhesive strength is enhanced by preparing a fine regular pattern in advance in a different polymer constituting the product exterior product. By controlling the pattern shape / density, the adhesion / bonding strength of different polymers is further increased.

FIG. 1 is a plan view showing a waterproof exterior product 10 according to the present invention, which has a structure in which a waterproof packing 14 made of silicone resin is bonded and formed in a rectangular shape on the back surface of a battery cover 12 of a cellular phone made of polycarbonate resin. ing.
When the battery cover 12 is attached to the main body of the mobile phone, the waterproof packing 14 is pressed against the periphery of the battery, so that liquid can be effectively prevented from entering the battery side.

Next, a method of bonding and forming the waterproof packing 14 on the back surface of the battery cover 12 will be described with reference to FIG.
First, a die 22 having a groove-shaped recess 20 for forming a waterproof packing formed in a rectangular shape on the surface is placed on a processing table 24, and the back surface of the battery cover 12 is placed thereon.
In this state, a certain load is applied to the surface of the battery cover 12, and the mold is clamped.

A tip gate 28 of the material supply pipe 26 is connected to one location of the groove-shaped recess 20 and a discharge nozzle 30 is connected to the opposite side of the connection location.
The rear end side of the material supply pipe 26 is bifurcated and includes a first rear end opening 32 and a second rear end opening 34.

Here, a mist-like primer containing an adhesive component is injected from the first rear end opening 32 of the material supply pipe 26. The primer spreads left and right along the groove-like recess 20 of the mold 22 and is discharged from the discharge nozzle 30 to the outside.
As a result, as shown in FIG. 3 (a), the primer adheres to the back surface of the battery cover 12 along the shape of the groove-shaped recess 20, and an adhesion ready state is realized. The portion where the primer is attached and the preparation state for adhesion is completed is referred to as an adhesion preparation region 38.

  This primer contains, for example, a titanate-based, amino-based, silica-based, epoxy-based, methacrylic-based, acrylic-based, or isocyanate-based polymer based on an organic solvent (n-heptane, ethanol, n-hexane). Made of polymer.

Next, thermosetting silicone resin is injected from the second rear end opening 34 of the material supply pipe 26. This silicon resin spreads left and right along the groove-like recess 20 of the mold, and a part thereof is discharged from the discharge nozzle 30 to the outside.
As a result, as shown in FIG. 3 (b), the silicon resin 40 is tightly filled between the back surface of the battery cover 12 and the groove-shaped recess 20 of the mold 22.

  Next, after the silicone resin 40 is thermally cured, the battery cover 12 is pulled up, whereby the waterproof packing 14 made of the silicone resin 40 is bonded to the back surface thereof as shown in FIG.

Instead of mixing the adhesive component with the material for forming the waterproof packing 14 as in the past, a primer containing the adhesive component is applied to the back surface of the battery cover 12 to form the adhesion preparation region 38, and then the silicon resin Since 40 is a mechanism in which the mold 22 is filled, excess or deficiency of silicon resin is less likely to occur.
In addition, since the primer is applied to a necessary portion using a mold 22 for silicon resin, burrs are hardly generated, and since it does not contain an adhesive component even if it protrudes, it can be easily removed.

  As shown in FIG. 4, the bonding strength between the silicon resin 40 and the battery cover 12 can be increased by forming a large number of fine linear recesses 42 in advance in at least the adhesion region on the back surface of the battery cover 12. it can.

Specifically, it corresponds to forming a large number of linear concave portions 42 with a groove width of 40 μm and a depth of 11 μm at intervals of 80 μm.
Of course, the configuration of the linear recess 42 is not limited to this, and the linear recess 42 having various dimensions can be formed at various intervals according to the material and application.
Alternatively, in place of the linear recess 42, a large number of fine dot-like recesses can be formed.

  For example, the recess (microtexture) is formed by irradiating a die (not shown) for forming the battery cover 12 with an ultrashort pulse laser such as a picosecond laser or a femtosecond laser. In addition, this is realized by transferring this when the battery cover 12 is formed.

It is a top view which shows the structure of the waterproof product which concerns on this invention. It is sectional drawing which shows the in-mold adhesion molding method between the different types of polymers concerning this invention. It is an expanded sectional view showing each process of an in-mold adhesion molding method between different kinds of polymers concerning this invention. It is an expanded sectional view which shows a mode that many fine linear recessed parts were formed in the surface of to-be-joined object.

10 Waterproof exterior products
12 Battery cover
14 Waterproof packing
20 grooved recess
22 Mold
24 Processing table
26 Material supply pipe
28 Tip gate of material supply pipe
30 Discharge nozzle
32 First rear end opening of material supply pipe
34 Second rear end opening of material supply pipe
38 Adhesive preparation area
40 Silicone resin
42 Linear recess

Claims (4)

A step of clamping the surface of an object to be joined made of the first polymer to a mold for molding a bonded article by insert mold clamping;
A step of injecting a primer containing or dissolving an adhesive component into the recess from the gate communicating with the recess of the mold to form an adhesion preparation region on the surface of the object to be joined;
Injecting molten second polymer from the gate and filling the recess with the second polymer;
Removing the second polymer joined to the adhesion preparation region on the surface of the first polymer article from the mold after the second polymer has solidified;
An in-mold adhesive molding method between different types of polymers. Mold adhesion molding method between heterogeneous polymer according to claim 1, characterized in that pre-provide a step of forming a large number of at least fine recesses in a region corresponding to the adhesive preparation region definitive on the surface of the object to be bonded.   The mold for forming the object to be bonded is irradiated with an ultrashort pulse laser to form a large number of recesses, and the recesses of the object to be bonded are formed by transferring the recesses. The method for in-mold adhesion molding between different polymers according to claim 2. A step of clamping the surface of an object to be joined made of the first polymer to a mold for molding a bonded article by insert mold clamping;
A step of injecting a primer containing or dissolving an adhesive component into the recess from the gate communicating with the recess of the mold to form an adhesion preparation region on the surface of the bonded product;
Injecting the second polymer for forming a packing from the gate in a melted state, and filling the second polymer into the recess;
Removing the second polymer joined to the adhesion preparation region on the surface of the first polymer article from the mold after the second polymer has solidified;
A method for producing a waterproof product.

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