JP4911401B2 - Plastic molded product having double wall and method of welding and joining - Google Patents

Description

  The present invention relates to a plastic molded article having a double wall in which an outer wall and an inner wall are welded and joined by a laser welding method, and a method for welding and joining the double walls.

For example, Patent Document 1 describes an invention relating to a cosmetic container in which a transparent outer container is externally fitted and formed into a double wall to an opaque inner container for protecting contents. By making the container into a double wall shape in this way, the inner container having a shielding effect suppresses the deterioration of the quality of the cosmetics, and in combination with the transparent outer container, the entire container is rich and varied. An excellent decorative effect can be exhibited.
JP-A-10-59357

  As a method of assembling and fixing the outer member and the inner member in a container having a double wall, in Patent Document 1, an engagement piece is provided at the upper end of the inner container, and an engagement notch is provided in the outer container. The method of fitting the piece into the engagement notch and assembling, and the method of assembling and fixing the both with the assembly ring, which is the third member, are described, but in this method the shape of the molded product is complicated Or the number of parts increases.

  On the other hand, as a method of assembling and fixing the two members by welding and joining, there is also a method using ultrasonic waves, high frequency, spin, etc., but it is difficult to sufficiently control the range and amount of melting of the resin at the welding surface part, Excessive resin may flow out from the welding surface and the appearance may be impaired. Also, the welding method using ultrasonic waves melts while vibrating the welding surface, so it will inevitably generate wrinkles at the joints, or may be whitened by heat depending on the resin, especially when the outer member is transparent In addition, there is a problem that bonding of inclined surfaces or the like is basically impossible.

  An object of the present invention is to create a method for welding and joining an outer member and an inner member, which can be easily assembled without complicating the shape of the member and does not impair the appearance even when a transparent outer member is used. Accordingly, an object of the present invention is to provide a plastic molded article having a double wall with high function and high decorativeness.

Of the present invention for solving the above technical problem, the means of the first invention is:
In the plastic molded product in which the inner member is fitted and assembled to the outer member having transparency to form a double wall,
With the insertion limit of the inner member, the two inclined surfaces formed with inclination with respect to the insertion direction are in contact with both members, and the positioning of both members is performed.
Both inclined surfaces were welded and joined by laser light irradiation from the outer member side in the contact state,
It is in.

With the above-described configuration of the first invention , the inner member is positioned by contacting the inclined surfaces formed by inclining the two members with respect to the inserting direction at the limit of insertion of the inner member. The operation of inserting and assembling the members can be performed smoothly along both inclined surfaces. In addition, in a state where both inclined surfaces are in contact with each other, by applying a pressing force in the insertion direction, both the inclinations can be brought into close contact with each other, and welding joining can be reliably achieved.

  The method using laser light irradiation does not apply dynamic displacement on the contact surface unlike the method using ultrasonic waves or spin, so that the pressing force acts obliquely on the contact surface. However, welding and joining can be carried out smoothly and reliably.

In addition, the laser beam is excellent in straightness, and the luminous flux does not diffuse, so that it is possible to irradiate a predetermined portion of the contact surface in a limited manner, that is, the melting range of the resin can be controlled with high accuracy. Even if the width of the contact surface is in millimeters, the resin is not melted excessively, and it is possible to prevent excess molten resin from flowing out of the contact surface. In addition, since the melting of the resin in the vicinity of the abutting surface proceeds extremely statically, the molten resin does not cause wrinkles or whitening at the cooled and solidified portion, so the outer member is transparent. Even if it exists, an external appearance is not impaired by the welding joining part.
In the present invention, “having transparency” includes translucency and some visible light transparency.

According to a second aspect of the present invention , in the first aspect, the two inclined surfaces are provided around the inner peripheral surface of the outer member and the outer peripheral surface of the inner member.

With the above-described configuration of the second aspect of the present invention , the outer member and the inner member can be easily and stably positioned by providing both inclined surfaces.
In addition, the welding joining of both inclined surfaces by laser light irradiation does not necessarily need to weld over the perimeter, For example, according to a use purpose, a welding part can also be formed in several positions at equal center angles. .

According to a third aspect of the present invention , in the first or second aspect of the invention , the outer member is made of a transmissive resin related to laser light, and the inner member is made of a non-transmissive resin.

The above-described configuration of the third invention relates to a specific method for melting the resin in the vicinity of the contact surfaces of both inclined surfaces, and this configuration is generally referred to as an LTW (Laser Transmission Welding) method. This is a method in which a plastic part that transmits laser light (transparent resin part) and a plastic part that absorbs laser light (non-transparent (light-absorbing resin part)) are stacked and pressed with an appropriate pressure to transmit the laser light. This is a method of irradiating from the side of the transparent resin component, in which the laser beam is transmitted through the transparent resin component, and the non-transparent resin component is heated and melted in the vicinity of the boundary surface to weld and join both components.

  Then, the limited range in the vicinity of the contact surfaces of the both inclined surfaces can be limitedly melted by this LTW method to achieve welding joint with high accuracy.

Here, as the transparent resin related to the laser light, amorphous transparent resin such as polystyrene, polycarbonate, PMMA (methacrylic acid resin), crystalline transparent such as polyethylene terephthalate, low density polyethylene, polypropylene, polyamide resin, Or most general synthetic resins, such as a semi-transparent synthetic resin, can be used.
As the non-transparent resin, a synthetic resin in which a pigment that absorbs laser light or a light-absorbing colorant of dye is dispersed is used.

According to a fourth aspect of the present invention , in the first, second, or third aspect of the invention , the focal point of the laser beam is formed on the contact surface and welding is performed.

The configuration of the fourth aspect of the invention also relates to a specific method for melting the resin with abutment surface near the both inclined surfaces, the configuration of the fourth invention, both in particular melted to the point-like This method is suitable for joining inclined surfaces. Here, even if it is made of the above-described transmissive resin, it absorbs the laser beam to some extent and generates heat, so that the light-absorbing colorant is not dispersed by narrowing the light beam and forming a focal point on the contact surface. However, it is possible to join both surfaces by melting in a point shape.

According to a fifth aspect of the present invention , in the first , second , third, or fourth aspect , the molded product is a cylindrical double container.

The above-described configuration of the fifth invention relates to a specific application example, and the double wall provides an excellent decorative effect that is rich in change and deep in containers for cosmetics and the like. Can be made.

According to a sixth aspect of the present invention , in the first , second , third, or fourth aspect of the invention , the molded product is a lid whose top plate has a double wall shape.

The above-described configuration of the sixth invention also relates to a specific application example. With the above-described configuration of the sixth invention , the top plate has a double wall, so that it can be changed to a lid for use such as a compact container. A rich and deep decorative effect can be achieved.

The seventh invention relates to a method of welding and joining a double wall formed by fitting and assembling a plastic inner member to a plastic outer member,
The method is
At the insertion limit of the inner member, both the inclined surfaces formed to be inclined with respect to the insertion direction on both members are in contact with each other, and the positioning of both members is performed.
In a state in which both inclined surfaces are in contact with each other, both members are pressed along the fitting direction, and a pressing force is applied between the inclined surfaces.
The laser beam is irradiated from the outer member side to weld and join both inclined surfaces.

By the above method of the seventh invention , both members are pressed in the insertion direction from the state where both inclined surfaces are in contact with each other, and a pressing force is applied between both inclined surfaces, so that the assembled state is stably maintained. The laser beam can be irradiated with both inclined surfaces in close contact with each other and pressed, and the resin can be melted and pressed with high precision and smoothness within a predetermined range of the inclined surfaces, thereby deteriorating the appearance. Without this, the double-wall welding can be easily achieved.

The present invention has the above-described configuration, and has the following effects.
In the first invention , the fitting operation of the inner member can be carried out smoothly, and in a state where both inclined surfaces are in contact, both the slopes are brought into close contact with each other by applying a pressing force in the fitting direction, Welding and joining can be achieved smoothly.

  In addition, the melting range of the resin in the vicinity of the contact surface can be controlled with high accuracy by laser light, and the melting of the resin can be prevented more than necessary, and the melting of the resin proceeds extremely statically, The melted resin does not wrinkle or whiten in the cooled and solidified portion, and even if the outer resin is transparent, the appearance is not impaired by the welded joint portion.

In the second aspect of the present invention , the outer member and the inner member can be assembled easily and stably by providing both inclined surfaces.

In the third invention , the limited range in the vicinity of the contact surfaces of the both inclined surfaces can be melted by the LTW method to achieve the welding joint with high accuracy.

In the fourth aspect of the invention , by focusing the light flux and positioning the focal point on the joining surface, it is possible to melt and join in a point shape even when the light-absorbing colorant is not dispersed.

In the fifth invention , due to the double wall, an excellent decorative effect which is rich in change and deep can be exhibited in a container for use such as cosmetics.

In the sixth aspect of the invention , by making the top plate a double wall, it is possible to bring out an excellent decorative effect that is rich in change and deep in a lid for a use such as a compact container. .

In the seventh invention , the assembled state is stably maintained, and the laser beam can be irradiated in a state in which both inclined surfaces are in close contact with each other and pressed, and is highly accurate and smooth within a predetermined range of the inclined surface. In addition, the melting of the resin and the pressure bonding can be advanced, and the double-wall welding can be easily achieved without impairing the appearance.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a half vertical front view of a double container having a double wall as a body portion according to the first embodiment of the present invention.
The outer member 1 is a bottomed cylindrical injection molded product made of polypropylene resin having transparency, and the inner member 2 is made of polypropylene resin in which a light-absorbing colorant is dispersed, and has a bottomed cylindrical body. It is a box-shaped blow-molded product in which the mouth tube portion 12 is erected.
In addition, an inclined surface 3a is provided around the inner peripheral surface at the upper end of the outer member 1, and an inclined surface 3b is provided around the outer peripheral surface at the upper end of the body portion of the inner member 2 (see also FIG. 2 (a)).

  FIG. 2 is an enlarged view of the shape in the vicinity of the portion surrounded by a circle in FIG. 1, and is a schematic explanatory view showing a method for welding and joining the outer member 1 and the inner member 2 of the double container 11. . FIG. 2A shows a method of assembling the inner member 2 to the outer member 1. The body portion of the inner member 2 is inserted into the body portion of the outer member 1, and finally the inclined surface of the inner member 2. 3b is inserted from above the inclined surface 3a of the outer member 1 along the insertion direction Di shown by the white arrow in the figure, and both the inclined surfaces 3a, 3b come into contact with each other, and the insertion limit is reached. Is done.

  FIG. 2B illustrates the welding and joining process using the laser beam L, and both the members 1 and 2 along the insertion direction Di in a state where both the inclined surfaces 3a and 3b are in contact and positioned as described above. Are pressed against each other and a pressing force is applied between the inclined surfaces 3a and 3b so that the inclined surfaces 3a and 3b are brought into close contact with each other. The surface 5 is irradiated and both inclined surfaces 3a and 3b are welded and joined.

  The welding method of the present embodiment is a method referred to as an LTW (Laser Transmission Welding) method, and an outer member 1 made of a transmissive resin that transmits laser light L and an inner member 2 made of a non-transmissive resin that absorbs laser light L. The laser beam L is irradiated from the outer member 1 while pressing the contact surface 5 with an appropriate pressure. Then, the laser beam L passes through the outer member 1 and heats and melts the resin of the inner member 2 in the vicinity of the contact surface 5. Further, this heat is conducted to the outer member 1 and the outer member 1 is also melted. The molten resins 1 and 2 are pressure-bonded by the pressing force, and both inclined surfaces 3a and 3b are welded and joined.

  Here, since both the inclined surfaces 3a and 3b are in contact with each other at the insertion limit of the inner member 2 and the positioning of the members 1 and 2 is performed, the inner member 2 is fitted along the both inclined surfaces 3a and 3b. Assembling operation can be carried out smoothly, and both inclined surfaces 3a and 3b are brought into close contact with each other by applying a pressing force in the fitting direction Di in a state where both inclined surfaces 3a and 3b are in contact with each other. Bonding can be reliably achieved.

  Further, since the predetermined portion of the contact surface 5 can be controlled to be limitedly controlled by the laser beam L, the outer member 1 is transparent without generating wrinkles or whitening in the cooled and solidified portion. In addition, the appearance is not impaired by the joint portion.

In addition, the welding joining of both the inclined surfaces 3a and 3b can be welded over the entire circumference, for example, it can be welded in a point shape at a plurality of locations at equal central angles, and the strength of assembly, appearance, etc. can be improved. You can select it while considering it.
And in the molded product which has rotational symmetry around the central axis as in this embodiment, when welding over the entire circumference, the position of the irradiation device M is fixed and the double container 11 is used as a rotating jig. A method of irradiating the laser beam L while fixing and rotating around the central axis can be applied. Further, in the case where welding is performed at, for example, four positions at an equal central angle, a method of applying a method of welding by arranging the irradiation device M at four facing positions can be applied.

  Moreover, in this embodiment, the inner member 2 can be prevented from being deteriorated in the quality of contents such as cosmetics by providing light-shielding properties by coloring. In addition, with respect to the outer member 1 and the inner member 2, various forms of decoration such as printing, vapor deposition, and hot stamping can be added depending on the purpose of decoration. The outer member 1 can also be colored within a range where transparency or semi-transparency can be maintained, and further adding a sense of quality by dispersing the filler or the like to make the outer member 1 milky white. You can also.

  3 and 4 illustrate a lid 21 for a compact container according to a second embodiment of the present invention. The planar shape of the lid 21 is circular, and is used by being mated with a thin dish-shaped compact container body by a hinge. FIG. 3 is a longitudinal front view of the lid body 21 in which two members of the outer member 1 and the inner member 2 are assembled and the top plate is a double wall. Here, the outer member 1 is made of milky white translucent ABS resin, and the inner member 2 is made of ABS resin in which a light-absorbing colorant is dispersed.

FIG. 4 is an enlarged view of the shape in the vicinity of the portion surrounded by a circle in FIG.
It is a schematic explanatory drawing which shows the welding method of the outer member 1 and the inner member 2 of the cover body 21 which used the top plate as the double wall.
FIG. 4A shows a method of assembling the inner member 2 to the outer member 1. Assembling is performed by inserting the flange portion 22 of the inner member 2 into the peripheral edge of the lower end of the outer member 1 and finally both inclined surfaces. It becomes the insertion limit which 3a and 3b contact | abut, and both members 1 and 2 are positioned.

  FIG. 4B illustrates the welding and joining process using the laser beam L. In the same manner as described in the first embodiment, the insertion direction in a state where both inclined surfaces 3a and 3b are in contact and positioned. Both members 1 and 2 are pressed against each other along Di, a pressing force is applied between the inclined surfaces 3a and 3b, and the both inclined surfaces 3a and 3b are in close contact with each other, and irradiation is performed from the outer member 1 side. The apparatus M irradiates the contact surface 5 with laser light L, and welds and joins both inclined surfaces 3a and 3b.

Thus, by welding and joining the two inclined surfaces 3a and 3b by irradiation of the laser beam L, the outer member 1 and the inner member 2 can be firmly assembled and fixed, and the top plate can be made into a double wall, The combination of the milky white and translucent outer member 1 and the colored inner member 2 allows the lid 21 to exhibit an excellent decorative effect rich in change and deep.

  As described above, the plastic molded product having a double wall according to the present invention can be easily assembled without complicating the shape of the member, and does not impair the appearance even when a transparent outer member is used. It is expected that the double wall can exhibit an excellent decorative effect that is varied and deep, and is widely used and deployed in the field of cosmetic containers and the like.

It is a half vertical front view which shows the double container which is 1st Example of the molded article of this invention. (A) in the welding joining of the outer side member and inner side member of the container of FIG. 1 is a schematic explanatory drawing which shows an assembly | attachment process, (b) is a welding process. It is a vertical front view which shows the cover body which is 2nd Example of the molded article of this invention. (A) in the welding joining of the outer side member and inner side member of the container of FIG. 3 is a schematic explanatory drawing which shows an assembly | attachment process and (b) is a welding process.

DESCRIPTION OF SYMBOLS 1; Outer member 2; Inner member 3a; (Outer member) Inclined surface 3b; (Inner member) Inclined surface 5; Contact surface (joint surface)
11; double container 12; mouth tube portion 21; lid 22; flange portion M; irradiation device L; laser beam Di;

Claims (5)

A synthetic resin inner member (2) in which a light-absorbing colorant composed of a pigment or dye that absorbs laser light is dispersed is fitted into the outer member (1) made of a transparent resin related to the laser beam (L). a synthetic resin molded article to form a double wall, said at insertion limit of the inner member (2), an inner circumferential surface and an inner member of the outer member is inclined with respect to the fitting ingress direction (1) (2 The two inclined surfaces (3a, 3b) provided around the outer peripheral surface of the outer contact surface are in contact with each other to position the members (1, 2). by laser light irradiation (L), the both inclined surfaces abutting (3a, 3b), a plastic molded article, characterized in that welded joint. Abutment surface to thereby form a focus of the laser beam (L) fusion bonded claims 1 plastic article according. The plastic molded article according to claim 1 or 2 , wherein the molded article is a cylindrical double container (11). The plastic molded article according to claim 1 or 2 , wherein the molded article is a lid (21) whose top plate (22) has a double wall shape. A method of welding and joining a double wall formed by inserting and assembling a plastic inner member (2) to a plastic outer member (1),
The outer member (1) is made of a transmission resin related to the laser beam (L), and the inner member (2) is made of a synthetic resin in which a light absorbing colorant composed of a pigment or dye that absorbs the laser beam is dispersed,
Wherein at insertion limit of the inner member (2), an inner peripheral surface both inclined surfaces provided around the outer peripheral surface of the inner member (2) of the outer member (1) is inclined with respect to the fitting ingress direction (3a, 3b) are in contact with each other and the positioning of both members (1, 2) is made, and in the state where both inclined surfaces (3a, 3b) are in contact, both members (1, 2) are aligned with each other along the insertion direction. pressed, the both inclined surfaces (3a, 3b) in a state in which the action of pressing force between, by irradiating laser light (L) from the outer member (1) side, the both inclined surfaces (3a, 3b) A method of welding and joining double walls to be welded and joined.

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