JPH10194303A - Resin bag with zipper and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin bag with a zipper which is artistic with no design restrictions, and to provide the method for producing the same inexpensively and good in quality. SOLUTION: Using thermoplastic resin and a resin bag with a zipper with a thermoplastic resin film attached on the tape part of the thermoplastic resin zipper whose teeth part and tape part are integrally injection formed, the teeth part and the tape part of the zipper are integrally injection formed, the thermoplastic resin film is adhered to the tape part and the resin bag is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fastener-equipped resin bag in which both the fastener and the film are made of resin, and a method for producing the same.

[0002]

2. Description of the Related Art Zippered resin bags are widely used for stationery, portable cases, resin bags, and the like. However, most of the shapes are limited. The biggest reason is that the fastener is manufactured by extrusion molding, so that the engagement portion of the fastener is limited to a linear shape. In addition, for some stationery, etc., a resin bag with a zipper having a curved toothed part is also commercially available, but such a resin bag is manufactured by secondary bending at the corner part. For this reason, wrinkles, distortions, and the like are generated, and as a result, not only the product value is reduced due to the reduction in design, but also the slider slidability at corners is problematic at present.

[0003]

SUMMARY OF THE INVENTION Accordingly, the present invention is to provide a resin bag with a zipper which is not restricted in design and is excellent in design, and a method for producing the resin bag inexpensively and with good quality. It is.

[0004]

The resin bag with a zipper of the present invention is manufactured by injection molding a thermoplastic resin for each of the male and female parts of the zipper, and then bonding the film, preferably by high-frequency heating welding or super-heating. Sonic heating and welding
After commercializing or inserting the film into the injection mold and injecting the thermoplastic resin into the product, the product is made into a product, so the fastener is the shape of the injection mold and the film is the shape of the trimming mold. Design is possible. In addition, since secondary bending, which causes deterioration in quality such as wrinkles and strains, is not required, a product with low cost and stable quality can be obtained.

That is, the gist of the present invention is that (1) a thermoplastic resin film is adhered to the tape portion of a thermoplastic resin fastener in which a tooth portion and a tape portion are integrally formed by injection molding. The resin bag with a fastener and (2) a thermoplastic resin are injection-molded integrally with a tooth portion and a tape portion of the fastener, and a thermoplastic resin film is adhered to the tape portion to form a resin bag. A method for manufacturing a resin bag with a fastener according to any one of claims 3 to 3.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION A resin bag with a fastener according to the present invention comprises a fastener made of a thermoplastic resin and a thermoplastic resin film, and the fastener further comprises a toothed portion and a tape portion integrally formed by injection molding. ,Also,
The film must be adhered to the tape section. On the other hand, the method of manufacturing a resin bag with a fastener according to the present invention includes at least two steps, namely, an injection molding step of a thermoplastic resin and a tape of a thermoplastic resin film for integrally forming the tooth section and the tape section. The step of bonding to the part is essential. However, as described above, when using a mold into which a thermoplastic resin film is inserted during injection molding, both of these steps are performed simultaneously.

Hereinafter, a resin bag with a fastener according to the present invention and a method for manufacturing the same will be described with reference to the accompanying drawings. FIG. 1 is a schematic process diagram illustrating an example of a method for manufacturing a resin bag with a fastener according to the present invention. FIGS. 2A and 2B are plan views respectively showing an example of a resin bag with a fastener of the present invention and a fastener manufactured by injection molding. FIGS. 3A and 3B are schematic cross-sectional views showing a process of bonding a fastener and a film using a bonding die. Thus, the fastener shown in FIG. 3A corresponds to an enlarged cross section taken along line BB ′ of FIG. 2B.

In the figure, (1) is a tooth portion, (2) is a tape portion, (3) is a fastener, (4) is a film, (5) is an adhesive portion, (6) is a slider, and (8) is Gate section,
(9) is a runner part, (10) is a resin bag with a zipper, (20) is an adhesive type, (21) is a runner-shaped groove, and (22) is a flat part.

In the method of the present invention, a fastener made of a thermoplastic resin in which a tooth portion and a tape portion are integrally formed is manufactured by injection molding in the method of the present invention. Then, as shown in FIG.
The fastener (3) has a shape that is thinner than the flow length,
Often a small cross section. Therefore, due to insufficient resin fluidity, short shots often occur when the number of resin inflow gates is small, and inconveniences such as the occurrence of weld lines even when the number of inflow gates is large often occur. Such a defect is caused by injecting the molten resin into the cavity for forming the fastener (3) from the film gate or multi-gate provided along the longitudinal direction of the cavity, and installing a runner before entering the gate. It can be solved by passing through. In this case, after the injection molding, the molded product taken out by opening the mold is provided with a runner portion (8) and a gate portion (9) where the resin is solidified in the runner and the gate as shown in FIG. The runner portion is cut off from the fastener at this gate portion in a later step.

The raw material of the thermoplastic resin film used for the production of the resin bag may be either a roll or a sheet. These raw materials are cut using an appropriate trimming mold to obtain a film having a shape conforming to the design of the final product.

As the material, the fastener is a thermoplastic resin which can be produced by injection molding, and the film is a roll or sheet of thermoplastic resin which is commercially available. For example, polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as 6-nylon, 66-nylon, 610-nylon, 11-nylon and 12-nylon, hard and soft vinyl chloride resins , An acrylic resin, a polycarbonate, a polystyrene, a polyester elastomer, a polyamide elastomer, a polyurethane elastomer and the like. Any thermoplastic resin may be used as long as it can be processed by injection molding, bonding, or the like.

[0012] Preferably, a thermoplastic resin capable of high-frequency heating welding or ultrasonic heating welding may be used. Preferably, the fastener and the film are both made of a soft polyvinyl chloride resin composition from the viewpoints of cost and workability. Here, the soft polyvinyl chloride-based resin composition refers to a plasticizer of 10 parts by weight or more based on 100 parts by weight of the polyvinyl chloride-based resin, and is necessary for expressing various properties such as weather resistance, cold resistance, and good moldability. It contains appropriate amounts of heat stabilizer, lubricant, filler, modifier, pigment and the like. The soft polyvinyl chloride resin composition can be set to a desired hardness by the content of the plasticizer, and is excellent in high-frequency heat welding property and ultrasonic heating welding property. It is the most preferable material for the bag.

A fastener manufactured by injection molding (generally, a pair of male and female which can be fitted to each other with different shapes of engaging teeth, but in the present specification, both refer to both unless otherwise specified. ) And the film obtained by the cutting are preferably subjected to an annealing treatment prior to commercialization, for example, before the bonding step. In this treatment, the surface temperature of each member, that is, the fastener or the film is adjusted to 40 ° C. or more and 120 ° C. or less for 2 seconds to
This is done by heating under conditions that are maintained for less than a time. This is a process taking into account that some molding distortion generally remains in a molded article of a thermoplastic resin regardless of the molding method. If a final product is produced with molding distortion remaining, shrinkage or deformation due to residual stress occurs depending on the storage and use conditions, and as a result, wrinkles and deflections often occur in the product. Annealing treatment under the above-described conditions is an effective means for relaxing this residual stress. When the heating temperature is lower than 40 ° C., there is no effect of relaxing the residual stress, and when the heating temperature exceeds 120 ° C., the resin molded article may be deformed. If the time is less than 2 seconds, the effect is not obtained, and if the time exceeds 5 hours, the effect is not increased, and it is uneconomical.

In the bonding step, a pair of fasteners (3) manufactured by injection molding are bonded (5) to the film (4) cut into a predetermined shape at each tape portion (2). The bonding step after injection molding is preferably performed by high-frequency heating welding or ultrasonic heating welding. Normal heat welding is not economical because not only is there a concern that heat will be applied to portions other than the position where welding is to be performed, but also the process time is extremely long.

In the method of the present invention, when the fastener and the film are bonded after injection molding, it is preferable to use a bonding die engraved with a runner shape. For example, FIG.
When using the bonding die (20) shown in (a) and (b), first, the runner portion (9) of the fastener is inserted into the runner-shaped groove (21) cut into the bonding die (20). It is positioned by burying it. In other words, the runner part functions as a shape stable fixed guide. Therefore,
The shape of the groove portion (21) is preferably prepared so that the runner portion (9) is securely accommodated and does not float in the groove portion (21) after being accommodated. Next, the cut film (4) is set so as to be overlapped at a predetermined position on the tape portion (2) of the fastener, and the overlapped portion is bonded, preferably by high-frequency heating welding or ultrasonic heating welding. I do. In order to surely perform this superposition, it is preferable that the height of the flat portion (22) of the bonding die (20) in contact with the tape portion (2) of the fastener is matched with the surface of the tape portion. That is, this makes it possible to set the film (4) at a predetermined position without fail. In addition, since the flat portion (22) has a stepped shape lower by the thickness of the tape portion at the position where the flat portion (22) is in contact with the tape portion (2), it also plays an important role in positioning the fastener. .

In general, fasteners are often long and thin in design.
Bending and other deformations make positioning for bonding difficult. Therefore, if the shape at the time of injection molding is created so that the above-mentioned runner part (9) can be set on the bonding die (20) for positioning, positioning becomes easy,
Poor quality due to misalignment can be reduced. For example, if the volume of the runner is too small compared to the volume of the cavity forming the tooth portion (1) and the tape portion (2), the above-described bending is unavoidable, and the bottom surface of the tape portion of the fastener is bonded. When placed on the mold, it does not form a predetermined plane. On the other hand, if it is too large, the molding yield of the resin is undesirably deteriorated. Further, the cross-sectional shape of the runner (9) is not limited to the circular shape shown in FIG.
It may be a polygon, a semicircle, an ellipse, or the like. The arrangement of the runner part (9) may be close to the tape part (2) as shown in FIG. 3 (a) or may be close to the tooth part (1) as shown in FIG. 3 (b). .

After the bonding step (including the case where the bonding step is carried out simultaneously with the above-mentioned injection molding, the same applies hereinafter), the above-mentioned step of releasing the runner portion is carried out to obtain a film with a fastener. On the other hand, the separated runner portion can be pulverized and recycled again as a raw material in the injection molding process. Note that if there is no deformation that hinders the adhesion of both the fastener and the film used for productization, the runner part is cut off before the bonding step, for example, before the annealing process or before the bonding after the annealing process. You can do it too. Of course, if there is no need for an annealing treatment, cut-off is performed before bonding after injection molding or cutting. However, even in these cases, it is preferable to use the bonding mold for positioning the fastener when bonding the fastener and the film.

Production after the bonding step is performed according to a conventional method. That is, in the assembling step, a pair of zipper-equipped films each having male and female teeth formed in the previous step and a slider for controlling opening and closing of the fastener are combined. In this step, the positioning of the fastener is facilitated by engaging the male and female of the engagement tooth portion of the fastener before combining the slider.

In the bag bottom welding step, a non-fastener-bonded side and a fastener end of the outer periphery of the resin bag of the final product are welded to another corresponding portion. Also in this welding step, high-frequency heating welding or ultrasonic heating welding is preferable for the same reason as described in the bonding step. Of course, this step can be omitted if a bottomed film is prepared.

The resin bag with a zipper of the present invention manufactured in this manner can take various shapes other than the rectangular shape with rounded corners shown in FIG. This is because the shape of the fastener is not particularly limited to the conventional linear type, but can be any shape. For example, the film to which the fastener adheres to a circle, an arc, an S-shape, etc. Examples include a circle, a rectangle having an arc-shaped top, a circle having a chord, and the like. Therefore, the resin bag of the present invention is used for a wide range of applications such as for stationery, portable cases, and resin bags.

[0021]

According to the present invention, since there is no restriction on the very important design shape due to the nature of the product, a resin bag with a zipper having a high commercial value can be obtained. Furthermore, the method of the present invention, which is a manufacturing method thereof, is an injection molding step of a fastener, and a bonding step with a film, preferably a high-frequency or ultrasonic heating welding, so that it is inexpensive and has excellent design. Products can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic process diagram showing an example of a method for manufacturing a resin bag with a fastener according to the present invention.

FIG. 2 is a plan view showing an example of a resin bag with a fastener of the present invention and a fastener manufactured by injection molding.

FIG. 3 is a schematic cross-sectional view showing a step of bonding a fastener and a film using a bonding die.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 tooth section 2 tape section 3 fastener 4 film 5 bonding section 6 slider 8 gate section 9 runner section 10 resin bag with fastener 20 bonding die 21 runner-shaped groove 22 flat section

Claims (11)

[Claims] 1. A resin bag with a fastener, wherein a thermoplastic resin film is adhered to said tape portion of a thermoplastic resin fastener in which a tooth portion and a tape portion are integrally formed by injection molding. 2. The resin bag with a fastener according to claim 1, wherein the resin fastener and the resin film are made of a soft vinyl chloride resin. 3. The resin bag with a fastener according to claim 1, wherein the resin fastener and the resin film are made of polyethylene or polypropylene. 4. The resin bag according to claim 1, wherein the engagement portion and the tape portion of the fastener are injection molded integrally using a thermoplastic resin, and a thermoplastic resin film is adhered to the tape portion to form a resin bag. 3. The method for producing a resin bag with a fastener according to any one of the above items 3. 5. The method for manufacturing a resin bag with a fastener according to claim 4, wherein the thermoplastic resin is injected from a film gate or a multi-gate through a runner to a tooth portion or a tape portion to form a fastener. 6. A zipper is formed by injecting a thermoplastic resin from a film gate or a multi-gate through a runner to a tooth portion or a tape portion, and after adhering the resin film, the runner is connected to the film gate or the multi-gate. The method for producing a resin bag with a fastener according to claim 4 or 5, wherein the resin bag is cut off. 7. The method according to claim 5, wherein the runner is buried in the bonding die engraved with the shape of the runner to position the fastener, the resin film is bonded, and then the runner is cut off at a film gate or a multi-gate portion. A method for producing a resin bag with a fastener according to claim 6. 8. The method for producing a resin bag with a fastener according to claim 4, wherein the bonding is welding. 9. The method for producing a resin bag with a fastener according to claim 8, wherein the bonding is high-frequency heating welding or ultrasonic heating welding. 10. The method for manufacturing a resin bag with a fastener according to claim 4, wherein a thermoplastic resin film is inserted into a predetermined portion of an injection molding die and then the thermoplastic resin is injection molded. 11. The method for manufacturing a resin bag with a fastener according to claim 4, wherein the fastener or the resin film is subjected to an annealing treatment and then bonded.