JP2003181932A - Method for connecting molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely obtain a high connecting strength irrespective of a type of a thermoplastic resin for constituting moldings 1, 2 to be connected when the moldings 1, 2 are connected to each other by utilizing the heat generated from a heating member 4 by interposing the member 4 capable of electrically generating the heat between the moldings 1 and 2 made of thermoplastic resins. <P>SOLUTION: A method for connecting the moldings comprises the steps of integrally providing the heating member 4 for generating the heat by energizing heating of induction heating in a state in which a part is exposed from a connecting surface 3 of the one molding 1, interposing the heated member 4 between the connecting surface 3 of the one product 1 having the member 4 and a connecting surface 5 of other molding 2 to be pressed into contact with each other, intruding the member 4 from the connecting surface 5 of the other molding 2 into its interior, and connecting the moldings 1 to 2 to each other. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention interposes a heat-generating member capable of electrically generating heat between molded products made of a thermoplastic resin, and uses the heat generated by the heat-generating members to join the molded products together. Regarding the method.

[0002]

2. Description of the Related Art Conventionally, as a method for joining molded products by utilizing the heat generated by a heat-generating member capable of electrically generating heat, a voltage is applied to a circumferential welded portion of a thermoplastic resin molded product. When a heat generating member with a circular or polygonal cross section that heats up is sandwiched in a circumferential shape and the heat generating members generate heat while pressing the molded products together, an annular groove is formed in the welded part of one molded product and a welded part of the other molded product. A method is known in which an annular rib that fits into the annular groove is provided, and the inner wall portion of the annular groove and the tip end portion of the annular rib are melted and fused by the heat of the heat generating member (Japanese Patent No. 2977035).

[0003]

However, in the above-mentioned conventional method, since the welded portions of both molded articles to be joined are melted by the heat of the heat-generating member to be heat-welded, the two methods to be joined in particular are described. When the molded product is composed of different types of resins having poor compatibility, there is a problem that sufficient bonding strength cannot be obtained. Even when the two molded products to be joined are made of the same kind of resin having good compatibility, sufficient joining strength can be obtained depending on the amount of the molten resin generated and the range of the joining surface into which the molten resin enters. It may not exist, and there is also a problem of lack of certainty.

The present invention has been made in view of the above problems of the prior art. A heat-generating member capable of electrically generating heat is interposed between molded articles made of a thermoplastic resin, and the heat generated by the heat-generating member is generated. An object of the present invention is to surely obtain a high bonding strength when bonding molded products by utilizing each other, regardless of the kind of thermoplastic resin forming the molded products to be bonded.

[0005]

According to the present invention, the conventional joining is heat welding by heat generation of the heat generating member, and the heat generating member is used only for melting the resin. The above object is achieved by functioning as a connecting member for joining the molded products.

That is, according to the first aspect of the present invention, a heat-generating member, which has generated heat due to electric heating or induction heating, is sandwiched between the joint surface of one molded article made of a thermoplastic resin and the joint surface of this one molded article. A molded product characterized by pressing the joint surfaces of the other molded product made of the thermoplastic resin, and causing the heat-generating member to penetrate into the interior of each of the molded products from the joint surface of both molded products to bond the molded products together. In the second aspect of the present invention, a heat generating member that generates heat by electric heating or induction heating is integrally formed in a state where a part of the heat generating member is exposed from the joint surface to which the other molded product made of the thermoplastic resin is joined. One molded article made of a generalized thermoplastic resin is formed, and the joint surface of one molded article having this heat generating member and the joint surface of the other molded article sandwich the heat generating member that has generated heat. Press together to reduce the heat generation Both by bite into the inside from the joint surface of the other of the molded article, there is provided a joining method of a molded article, which comprises bonding the molded article each other.

According to the present invention, the heat generating member is embedded in both molded products to be joined, and the heat generating member itself functions as a connecting tool. Therefore, a high bonding strength can be reliably obtained regardless of the type of resin of the molded product.

The second aspect of the present invention includes, as a preferred embodiment, that the supporting area of the heat generating member against the pressing force of both molded products is larger on the one molded product side than on the other molded product side. The above first and second aspects of the present invention
Means that the heat generating member is a plate-shaped body or a rod-shaped body made of metal, the engaging portion with the thermoplastic resin is formed in advance on the heat generating member, and the heat generating member is a metal coil. The preferred embodiments include pressing the molded products together in the radial direction of the coil and subjecting the surface of the heat-generating member to a surface treatment for improving the adhesion with the thermoplastic resin in advance.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be further described with reference to FIGS. 1 to 11, the same reference numerals denote the same members or parts.

1 and 2 show a first example of the present invention, in which 1 and 2 are molded articles made of thermoplastic resin.

The molded product 1 on the left side of the drawing is integrally formed with a heat generating member 4 which generates heat by electric heating or induction heating in a state in which a part of the molded product 1 on the right side of the drawing protrudes from a joint surface 3. It has become a thing.

The heat generating member 4 is a member that is electrically heated or induction-heated as described above, and, as will be described later, is a member that is embedded between the molded products 1 and 2 and joins them together. Therefore, it is preferable to use a material having conductivity and high mechanical strength. So, for example, iron, copper,
Metals such as these alloys are preferred.

The heat generating member 4 in the present example is a plate-like member, about half of which is embedded in the molded product 1 in the width direction, and the other half is outward from the joint surface 3 of the molded product 1. It is protruding.

The heat-generating member 4 can be integrated with the molded product 1 by outsert molding. For example, a recess for fitting the heat-generating member 4 into the molded product 1 is formed and the heat-generating member 4 is inserted into this recess. It may be carried out by fitting or adhering, but outsert molding is preferable because integration is easy and reliable.

The heat-generating member 4 is preferably surface-treated to improve the adhesion with the thermoplastic resin. Examples of the surface treatment include washing with an organic solvent, etching with phosphoric acid or maleic acid, application of a polar group, sandblasting, flame treatment and the like. By performing these treatments, the adhesion between the molded product 1 and the heat generating member 4 can be improved, and
At the time of joining, which will be described later, the adhesion between the molded product 2 and the heat generating member 4 can be improved, and the bonding force between the molded products 1 and 2 can be improved.

The thermoplastic resin forming the molded products 1 and 2 is
There is no particular limitation as long as it is generally used for injection molding or extrusion molding. For example, polystyrene, rubber-reinforced styrene resin (eg, high impact polystyrene, medium impact polystyrene, etc.), styrene-acrylonitrile copolymer (SAN resin), acrylonitrile-butyl acrylate rubber-styrene copolymer (AA
S resin), acrylonitrile-ethylene propyl rubber-styrene copolymer (AES), acrylonitrile-polyethylene chloride-styrene copolymer (ACS), ABS
Resin (for example, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-butadiene-styrene-alphamethylstyrene copolymer, acrylonitrile-methylmethacrylate-butadiene-styrene copolymer, etc.), modified polyphenylene ether (m-PPE)
Styrene resin such as; polymethylmethacrylate (P
Acrylic resin such as MMA); olefin resin such as low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP); polyvinyl chloride, polyvinylidene chloride, ethylene-vinyl chloride
Vinyl chloride-based resins such as vinyl acetate copolymers and ethylene-vinyl chloride copolymers; polyester-based resins such as polyethylene terephthalate (PETP, PET), polybutylene terephthalate (PBTP, PBT), polycarbonate (PC), modified polycarbonate, etc. Polycarbonate resin; Polyamide resin such as polyamide 66, polyamide 6 and polyamide 46; polyacetal (POM) such as polyoxymethylene copolymer and polyoxymethylene homopolymer; other engineering resin; polyether sulfone (PES), polyether Imide (PEI), thermoplastic polyimide (TP
I), polyetherketone (PEK), polyetheretherketone (PEEK), polyphenylene sulfide (PSU) and other super engineering resins; cellulose acetate (CA), cellulose acetate butyrate (CAB), ethyl cellulose (EC) and other celluloses. Derivatives; liquid crystal polymers such as liquid crystal polymers and liquid crystal aromatic polyesters; further, thermoplastic polyurethane elastomer (TPU), thermoplastic styrene butadiene elastomer (SBC), thermoplastic polyolefin elastomer (TPO), thermoplastic polyester elastomer (TPEE), Examples thereof include thermoplastic elastomers such as thermoplastic vinyl chloride elastomer (TPVC) and thermoplastic polyamide elastomer (TPAE).

The thermoplastic resin forming the molded products 1 and 2 is
It may be a blend of one or more thermoplastic resins. It is also possible to add commonly used additives such as plasticizers, colorants, ultraviolet absorbers, antistatic agents, and fillers. Inorganic substances are also included as the filler. For example, glass fibers, glass beads, calcium carbonate, mica, asbestos, powders of metals such as iron, copper, zinc and aluminum, hollow bodies, flakes, and metal oxides and metals of these metals. A hydroxide may be used.

The above-mentioned molded products 1 and 2 are joined to each other by joining the joining surface 3 of one of the molded products 1 from which the heat generating member 4 projects and the joining surface 5 of the other molded product 2 to be joined to the joining surface 3. This can be performed by sandwiching the protruding heat-generating member 4 and facing each other and pressing them against each other, and heating the heat-generating member 4 by electric heating or induction heating. When the heat generating member 4 generates heat and the joint surface 5 of the molded product 2 against which the heat generating member 4 is pressed melts, the heat generating member 4 is pushed into the joint surface 5 of the molded product 2, so that the joint surface 3 of the molded products 1 and 2 is melted. The molded products 1 and 2 can be joined by pushing them in until they come into contact with each other and cooling them. In addition, molded article 1,
The joining of 2 can also be performed by heating the heating member 4 to a required temperature and then pressing the joining surfaces 3 and 5 with the heating member 4 interposed therebetween.

When the molded products 1 and 2 are joined as described above, as shown in FIG.
The embedded products are laid across the space, and the molded products 1 and 2 can be joined via the heat generating member 4. Therefore, even if the thermoplastic resin forming the molded article 1 and the thermoplastic resin forming the molded article 2 are different types having poor compatibility or incompatibility, a firm and firmly joined state is surely obtained. be able to.

By the way, when the heat generating member 4 is pushed into the molded product 2 from the joint surface 5, the thermoplastic resin melted by the heat of the heat generating member 4 (mainly the thermoplastic resin forming the molded product 2) is bonded to the joint surface 5. Since it is extruded to the joint of 3 and 5, the heat fusion by this can also be used for joining.
From the viewpoint of enabling this heat fusion to be used in combination, it is preferable that the thermoplastic resin forming the molded article 1 and the thermoplastic resin forming the molded article 2 have good compatibility, and particularly the same kind of heat is used. It is preferably a plastic resin.

When the heating member 4 is heated and pushed in, it is preferable that the joint surfaces 3 and 5 are not melted as a whole. Joining surface 3,5
When the whole is melted, the joint surfaces 3 and 5 are pressed against each other to cause crushing and easily deformed, and the melt-recured thermoplastic resin is inferior in mechanical properties.
The holding force of the heat generating member 4 after cooling is reduced, and the bonding strength is likely to be reduced.

When the heat-generating member 4 is pushed in, the heated heat-generating member 4 is prevented from being largely pushed into the molded product 1 in which the heat-generating member 4 is previously integrated, so that the heat-generating member 4 is reliably pressed against the molded product 2. It is preferable to be able to push in the required amount. For that purpose, the molded product 1 can be cooled, but when the molded product 1 and the molded product 2 are pressed against each other via the heat generating member 4, the supporting area of the heat generating member 4 on the molded product 1 side against the pressing force. Is preferably larger than the supporting area on the molded product 2 side. This will be described in detail later. Further, by setting the melting point of the thermoplastic resin forming the molded product 1 higher than the melting point of the thermoplastic resin forming the molded product 2, it is possible to prevent the heat generating member 4 from being pushed into the molded product 1.

As described above, the heat generating member 4 can generate heat by electric heating or induction heating. However, in the case of electric heating, it is necessary to connect a conductive wire to the heat generating member 4, and normally this is done after joining. Although it takes time and effort to remove the conductive wire, induction heating such as high-frequency induction heating is preferable because it does not take such trouble.

FIGS. 3 and 4 show a second example of the present invention, which is basically the same as the first example described with reference to FIGS. 1 and 2, but the heat generating member 4 is a rod-shaped member. And about 1 / in the axial direction
2 is embedded in the molded product 1, and the remaining approximately 1/2 of the axial direction projects from the joint surface 3, and the molded products 1 and 2 are pressed and joined from the axial direction of the heat generating member 4.
When the heat-generating member 4 is a rod-shaped body as in this example, it is also possible to form a screw that is screwed into the molded product 1 and the heat-generating member 4 and to integrally mount the heat-generating member 4 on the molded product 1 by zip-fastening. it can.

The heat generating member 4 has engaging portions 6 and 6 at both ends.
It has seven. The engaging portions 6 and 7 engage the molded products 1 and 2 in the pulling-out direction of the heat-generating member 4 from the molded products 1 and 2, respectively, after the molded products 1 and 2 are joined. It is formed as a portion that has a larger diameter than the middle portion and projects outward. When such engaging portions 6 and 7 are provided on the heat generating member 4, the holding force of the heat generating member 4 of the molded products 1 and 2 is increased, and the joining force can be increased.

When the heat-generating member 4 is a rod-shaped member, the engaging portions 6 and 7 are provided as large-diameter portions formed at the ends of the heat-generating member 4 as described above, and are also formed on the peripheral surface of the heat-generating member 4. It can also be provided as a protrusion or a recess. The heat generating member 4 is shown in FIG.
In the case of the plate-like body described with reference to FIG. 2, it is provided as a hole or is formed into a corrugated plate-like body that undulates in the joining direction of the molded products 1 and 2, so that the undulations of the surface are engaged. It can also be 7.

5 and 6 show a third example of the present invention, which is basically the same as the first example described with reference to FIGS. 1 and 2, but the heat generating member 4 is a coil. , 1 / in the radial direction
2 is embedded in the molded product 1, and the remaining approximately 1/2 of the radial direction projects from the joint surface 3, and the molded products 1 and 2 are pressed and joined together from the radial direction of the heat generating member 4.

As described above, when the heat generating member 4 is a coil, the heat generating member 4 of the molded products 1 and 2 can be formed without providing the engaging portions 6 and 7 described in the second example of FIGS. 3 and 4. The holding force of the can be increased, and the joining force can be increased.

FIGS. 7 and 8 show a fourth example of the present invention, in which a molded product 1 having a heat generating member 4 has a recess 8 into which an end of a molded product 2 having a joint surface 5 is fitted. However, the bottom surface of the recess 8 becomes the joint surface 3. The heat generating member 4 is provided integrally with the molded product 1 so as to project from the joint surface 3 of the molded product 1 as described above.
Is similar to the example.

When the recess 8 is provided as described above, the end portion of the molded product 2 is held in the recess 8 after joining, so that the joining strength can be increased. In addition, the heat generating member is a molded product 2
The molten resin extruded as it is pushed into the joint surface 3,
Even if it sticks out from the joint of 5, it can be covered up.

In this example, the heat generating member 4 is used as the molded product 1.
Although it is provided in the concave portion 8 of the above, it may be provided integrally with the molded article 2 by projecting from the joint surface 5 of the molded article 2 instead. Also, in the first to third examples described above, the heat generating member 4 can be provided in the molded product 2.

In the first to fourth examples, the heat generating member 4 is integrally provided in the molded product 1 in advance.
The molded products 1 and 2 and the heat-generating member 4 are separately prepared, and the joint surface 3 of the molded product 1 and the joint surface 5 of the molded product 2 are pressed against each other with the heat-generating member 4 that has generated heat interposed therebetween, so that both heat-generating members 4 are joined together. It is also possible to join the molded products 1 and 2 by digging into the respective interiors from the bonding surfaces 3 and 5 of the molded products 1 and 2. However, it does not take time to position the heat generating member 4,
Since the joining operation becomes easy, it is preferable to previously provide the heat-generating member 4 integrally with one of the molded products 1 or 2 as in the first to fourth examples.

As mentioned above, when the heat-generating member 4 prepared as a separate member is used to join the molded products 1 and 2 made of the same thermoplastic resin, the molded products 1 and 2 are pressed with the heat-generating member 4 interposed therebetween. When combined, the heat generating member 4 is
It is preferable that the heat generating member 4 has a symmetrical shape in the joining direction of the molded products 1 and 2 so that the heating member 4 is pressed into the mold 2 as evenly as possible. Further, when the melting points of the thermoplastic resins forming the molded products 1 and 2 are different, the cross-sectional area of the molded product 1 or 2 side having a high melting point is made small and the cross-sectional area of the molded product 2 or 1 side having a low melting point is made large. It is preferable to use the heat generating member 4.

9 to 11 show the molded product 1 (molded product 2) in advance.
However, when the molded product 1 and the molded product 2 are pressed against each other via the heat generating member 4, the heat generating member 4 is prevented from being pushed into the molded product 1. Heat generation member 4 against pressing force so that
The heating member 4 shown in FIG. 9 is a plate-shaped body or a rod-shaped body, and the molded product 1 side has a larger supporting area on the molded product 1 side than the molded product 2 side. The end portion on the side has a flange-shaped receiving portion 9 protruding outward from the molded product 2 side. Further, the heat generating member 4 shown in FIG. 10 is a rod-like body and is similarly provided with the receiving portion 9, but the receiving portion 9 is more than the locking portion 7 provided at the tip of the molded product 2 side. It has a large diameter. Figure 11
The heat generating member 4 shown in (1) is a coil, and the receiving portion 9 is provided on the side embedded in the molded product 1 as a rod member or a plate member attached in the axial direction.

When the receiving portion 3 as described above is provided, it is easy to suppress the heat generating member 4 from being pushed into the molded product 1 side when the heat generating member 4 is heated to press the molded product 2 together. Therefore, the required amount can be surely pushed into the molded product 2.

[0036]

EXAMPLES Example 1 Plate-shaped test pieces of polystyrene (PS) and polyethylene (PE) were each tested to have a length of 127 mm and a width of 12.7 mm.
Created with a thickness of 6.3 mm, length (the direction of pushing into the molded product) 10 mm, width (direction perpendicular to the direction of pushing into the molded product) 6.3 mm, through hole of 1 mm diameter in a 0.1 mm thick iron plate. The zigzag shape is used as a heat generating member
The test piece and PE test piece were joined.

One end face of the PS test piece and the one end surface of the PE test piece are opposed to each other with the heat generating member washed with an organic solvent sandwiched therebetween, and a current of 5 V is applied to the heat generating member while being pressed by 5 kg from the other end faces of both test pieces. Then, the PS test piece and the PE test piece were made to generate heat, and the heat generating member was pushed into both test pieces until the end surfaces of the PS test piece and the PE test piece contacted with each other.

After both bonded test pieces were left to cool for 24 hours, the PS test piece side end and the PE test piece side end were mounted on a chuck of a tensile tester and pulled at a speed of 5 mm / min. The breaking load was measured. Breaking load is 25
It was kg.

Example 2 Example 1 was repeated except that a nichrome wire having a diameter of 0.5 mm was wound around a coil having a diameter of 3.0 mm as the heat generating member.
Bonding was performed in the same manner as in, and the breaking load was measured in the same manner as in Example 1. The breaking load was 35 kg.

Comparative Example 1 Using a test piece welding machine, the PS test piece and the PE test piece similar to those in Example 1 were joined together by heat welding. Welding is
Hot plate temperature 220 ℃, melting margin 1.0mm, melting time 20s
ec, crushing margin of fusion part by pressing together 1.0m
m, and the welding time was 30 sec.

Breaking load was measured in the same manner as in Example 1 for both the joined test pieces. The breaking load was 3 kg.

[0042]

The present invention is as described above, and it is possible to reliably obtain a high bonding strength even when the molded products to be bonded are made of different thermoplastic resins having poor compatibility. Therefore, it is useful for joining the molded products, which is difficult to obtain the required strength by the general welding process. In addition, particularly if one of the molded products is previously held integrally with the heat-generating member, it can be joined by being heated by energization or induction heating from the outside, so melting by pressing of a generally-used hot plate, It is also useful for joining parts where it is difficult to perform processing such as melting due to vibration heat generation and melting due to laser light.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first example of the method of the present invention.

FIG. 2 is a cross-sectional view of a joining portion according to the first example.

FIG. 3 is a perspective view showing a second example of the method of the present invention.

FIG. 4 is a sectional view of a joining portion according to a second example.

FIG. 5 is a perspective view showing a third example of the method of the present invention.

FIG. 6 is a cross-sectional view of a joining portion according to a third example.

FIG. 7 is a perspective view showing a fourth example of the method of the present invention.

FIG. 8 is a cross-sectional view of a joining portion according to a fourth example.

FIG. 9 is a cross-sectional view showing an example of a case where the supporting area on one molded product side of the heat generating member against the pressing force is made larger than the supporting area on the other molded product side.

FIG. 10 is a cross-sectional view showing another example of a case where the supporting area of one molded product side of the heat generating member against the pressing force is made larger than the supporting area of the other molded product side.

FIG. 11 is a cross-sectional view showing still another example of the case where the supporting area on one molded product side of the heat generating member against the pressing force is made larger than the supporting area on the other molded product side.

[Explanation of symbols]

1 molded product 2 molded products 3 joint surface 4 Heat generating member 5 Bonding surface 6 Engagement part 7 Engagement part 8 recess 9 Receiver

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Claims (7)

[Claims] 1. A joining surface of one molded article made of a thermoplastic resin and the other thermoplastic resin joined to the joining surface of this one molded article with a heating member that has generated heat by electric heating or induction heating interposed therebetween. 2. The method for joining molded articles, wherein the joined surfaces of the molded articles are pressed against each other, and the heat-generating member is made to penetrate into the inside of each of the joined surfaces of the molded articles to join the molded articles together. 2. One of a thermoplastic resin in which a heat generating member that generates heat by electric heating or induction heating is integrated in a state where a part of the heat generating member is exposed from a bonding surface to which the other molded product made of the thermoplastic resin is bonded. The molded surface of the molded article is formed, and the joint surface of one molded article having this heat generating member and the joint surface of the other molded article are pressed against each other with the heat generating member that has generated heat interposed therebetween, and at least this heat generating member is A method for joining molded articles, characterized in that the molded articles are joined together by digging into the inside from the joining surface of the other molded article. 3. The method for joining molded products according to claim 2, wherein the supporting area of the heat generating member against the pressing force of both molded products is larger on the one molded product side than on the other molded product side. 4. The method for joining molded products according to claim 1, wherein the heat generating member is a metal plate or rod. 5. The method for joining molded products according to claim 1, wherein an engagement portion with the thermoplastic resin is formed in advance on the heat generating member. 6. The method for joining molded products according to claim 1, wherein the heat generating member is a coil made of metal, and the molded products are pressed against each other in the radial direction of the coil. 7. The joining of the molded article according to claim 1, wherein the surface of the heat generating member is previously subjected to a surface treatment for improving adhesion with a thermoplastic resin. Method.