JPH09108084A - Tableware and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an addition amount of an antibacterial agent while securing antibacterial effect. SOLUTION: This invention relates to a tableware which comprises a skin layer 1 on the surface thereof and a core layer 2 inside. An antibacterial agent is contained in the skin layer 1. This enables the containing of the antibacterial agent in the skin layer 1 with the quantity thereof allowing a sufficient antibacterial effect even if the content of the antibacterial agent is reduced with respect the whole of the tableware.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to tableware containing an antibacterial agent and a method for producing the same.

[0002]

2. Description of the Related Art Tableware made of resin molding is less likely to be damaged than ceramic tableware and can be easily decorated.
Various types are provided because of their light weight and low cost. However, compared to ceramic tableware, resin-molded tableware has a problem that fungi, such as mold, easily propagate on the surface. Therefore, tableware containing an antibacterial agent formed by adding an antibacterial agent to a resin and molding the resin has been provided.

[0003]

In the tableware containing the antibacterial agent as described above, the antibacterial agent is necessary only on the surface of the tableware in order to prevent bacteria from propagating on the surface of the tableware. It is not necessary to contain it inside the thick wall. However, in order to add the antibacterial agent to the resin to mold the tableware, the antibacterial agent is contained even inside the wall thickness of the tableware,
The problem is that the antibacterial agent contained in unnecessary parts is wasted, and it is necessary to add a large amount of antibacterial agent in order to allow the antibacterial agent in an amount that prevents bacterial growth to exist on the surface of the tableware. was there.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a tableware and a method for producing the same in which the amount of the antibacterial agent added can be reduced while ensuring the antibacterial effect. is there.

[0005]

DISCLOSURE OF THE INVENTION The tableware according to the present invention is characterized by comprising a skin layer 1 on the surface and a core layer 2 on the inside, wherein the skin layer 1 contains an antibacterial agent. Is. The invention according to claim 2 is the core layer 2
Is formed of the same material as the skin layer 1 containing no antibacterial agent.

The invention according to claim 3 is characterized in that the core layer 2 is made of a recycled material. The invention according to claim 4 is characterized in that the core layer 2 is formed of a heat storage material. The tableware manufacturing method according to the present invention uses an injection molding machine 3 for three-layer molding including two cylinders 6a, 6b, and one nozzle 7, and an antibacterial agent is first introduced into the cavity 5 of the molding die 4 from one cylinder 6a. A skin layer formed by the skin material 9 by injecting the compounded skin material 9, then injecting the core material 10 from the other cylinder 6b, and then injecting the skin material 9 containing the antibacterial agent from the one cylinder 6a. 1 is characterized in that the tableware A having a three-layer structure in which the core layer 2 made of the core material 10 is wrapped is molded.

[0007]

Embodiments of the present invention will be described below. FIG. 1 shows an example of tableware A. A skin layer 1 made of a skin material 9 wraps a core layer 2 made of a core material 10 to form a three-layer structure in which both inner and outer surfaces are skin layers 1. is there. Then, the antibacterial agent is added only to the skin material 9 to form the tableware A, so that the surface skin layer 1
Only contains antibacterial agent. In this way, since the inner core layer 2 does not contain an antibacterial agent, even if the content of the antibacterial agent with respect to the whole dish A is reduced, the skin layer 1 has an antibacterial effect of a sufficient amount. The agent can be contained, and the amount of the antibacterial agent added can be reduced while ensuring the antibacterial effect on the surface of the tableware A.

FIG. 2 shows a three-layer injection molding machine 3 for molding the tableware A having a three-layer structure as described above. The three-layer injection molding machine 3 has two cylinders 6a, 6b.
1 equipped with both cylinders 6a and 6b
It is formed by including one nozzle 7. The skin material 9 is supplied from the hopper 16a to one cylinder 6a, and the core material 10 is supplied to the other cylinder 6b from the hopper 16b. Each cylinder 6a, 6
Screws 17a and 17b are provided in the b, respectively, and the skin material 9 and the core material 10 supplied from the hopper 16a and the hopper 16b are kneaded by the rotation of the screws 17a and 17b while being melted and sent forward, By advancing 17a and 17b, the melted skin material 9 and core material 10 are injected from the nozzle 7. Also, the nozzle 7 is one cylinder 6
The resin outflow passage 18 of a is formed in the nozzle chamber 19 through which the tip of the resin outflow passage 20 of the other cylinder 6b is introduced, and the tip of the nozzle 7 is opened as a nozzle port 21. is there.

In the present invention, an antibacterial agent is added to and mixed with the above-mentioned skin material 9. As the antibacterial agent, any conventionally provided antibacterial agent can be used and is not particularly limited. For example, a thiosulfato silver complex salt supported on silica gel provided in JP-A-7-233279 can be used. Can be used. Although the amount of the antibacterial agent added to the skin material 9 varies depending on the kind of the antibacterial agent,
Generally, the range of 0.5 to 7% by weight with respect to the skin material 9 is preferable.

As the skin material 9, a thermoplastic resin such as polypropylene resin (PP), polycarbonate resin (PC), polybutylene terephthalate resin (PBT), polyethylene terephthalate resin (PET), polyester elastomer, or a thermosetting resin is used. Can be used. Further, as the core material 10, a thermoplastic resin such as PP, PET, polyethylene (PE), polyamide resin (PA), polystyrene (PS), ethylene propylene copolymer resin (EP), polyester elastomer, or a thermosetting resin is used. be able to. For the skin material 9 and the core material 10, it is preferable to select and use a resin having a difference in softening temperature of 0 to 80 ° C.

The skin material 9 and the core material 10 may be made of the same resin. When the same resin is used as the skin material 9 and the core material 10 in this way, the skin layer 1 and the core made of the skin material 9 are made. Since the core layer 2 made of the material 10 is formed of the same resin, the tableware A can be formed as a substantially single layer structure, and the skin layer 1 and the core layer 2 can be formed.
There is no risk of delamination and the like between and.

Further, by using the above-mentioned resin mixed with the heat storage material as the core material 10, the heat storage material can impart the heat storage property to the core layer 2, and the tableware A can be provided by the heat storage effect of the core layer 2. It is possible to give the performance of keeping warm and cold. As the heat storage material, microcapsules of fluororesin or silicone resin and sodium carbonate (10
Hydrate), sodium sulfate (10 hydrate), calcium chloride (hexahydrate), sodium acetate (3 hydrate) and the like in an amount of 10 to 50% by weight based on the resin. Encapsulated substances, paraffins, polyhydric alcohols such as polyethylene glycol and polypropylene glycol, and the like can be used. This heat storage material preferably has a melting temperature of 45 to 70 ° C.

Further, as the core material 10, a recycled material obtained by recovering a resin such as polypropylene used for molding once (or a plurality of times) from a molded product may be used as it is, or the above resin may be mixed with the recycled material. it can. Since the core layer 2 formed from the core material 10 is not exposed on the surface, it is inexpensive, and even if a recycled material that is preferably reused for resource saving is used, there is no problem in appearance. is there. As such a recycle material, sprues, runners, burrs, and other wastes of the molded product can be crushed and used.

Therefore, the above-mentioned injection molding machine 3 for three-layer molding is used.
When the tableware A is molded by using the mold, the nozzle 8 of the nozzle 7 of the three-layer molding injection molding machine 3 is attached to the gate 8 of the molding die 4 including the fixed mold 4a and the movable mold 4b as shown in FIG. Combine. Then, first, the valve of the resin outflow passage 18 of the cylinder 6a is opened and the valve of the resin outflow passage 20 of the cylinder 6b is closed, and as shown in FIG.
Screw 17a is moved forward to move the skin material 9 to the nozzle 7
Is injected into the cavity 5 of the molding die 4. Next, the valve of the resin outflow passage 18 of the cylinder 6a is closed and the valve of the resin outflow passage 20 of the cylinder 6b is opened, and the screw 17b of the cylinder 6b is advanced to move the core material 10 out of the nozzle as shown in FIG. 2 (b). It is injected into the cavity 5. The core material 10 is injected into the cavity 5 so as to sneak into the skin material 9 that has been previously injected into the cavity 5, and the core material 10 pushes the skin material 9 to spread it out. Core material 10 in most of the space
And the skin material 9 is filled. After this, the valve of the resin outflow passage 18 of the cylinder 6a is opened again and the cylinder 6b is opened.
2 is closed, the screw 17a of the cylinder 6a is further advanced to inject the skin material 9 from the nozzle 7 into the cavity 5 of the molding die 4 as shown in FIG. The gate 8 portion of the mold 4 is filled with the skin material 9 so that the core material 10 is completely covered with the skin material 9 and the inside of the cavity 5 is completely filled with the core material 10 and the skin material 9. After that, by cooling and opening the molding die 4, it is possible to obtain a bowl A as shown in FIG. 1 or tableware A used as a bowl, a plate or the like.

As described above, the tableware A having a three-layer structure in which the core layer 2 is sandwiched between the skin layers 1 can be produced in one step of injection molding, and the three layers are individually molded. Compared with the case of manufacturing by laminating, the productivity is increased to about 3 times, and the production cost can be reduced. Moreover, since the skin layer 1 is molded so as to wrap around the core layer 2, there is no peeling at the bonded portion as in the case where the skin layer 1 and the core layer 2 are bonded, and boiling resistance or boiling resistance It is possible to improve durability such as properties, and it is also possible to prevent the bonded joint portion from appearing and impairing the appearance.

Here, as the above-mentioned molding die, it is preferable to use one in which a gate 8 is provided at or near the center of the cavity 5 (for example, the center of the bottom surface of the tableware A).
When the gate 8 is provided near the center of the cavity 5 as described above, the skin material 9 and the core material 1 injected into the cavity 5 are formed.
Since 0 is filled in the cavity 5 so as to spread from the vicinity of the center of the cavity 5 to the periphery, it becomes easy to fill the core material 10 with the skin material 9 in the cavity 5. It is easy to form the tableware A into a three-layer structure in which the skin layer 3 made of the skin material 9 wraps the core layer 2 made of the core material 10.

[0017]

The present invention will be described below in detail with reference to examples. (Example 1) As a skin material 9, a polypropylene resin ("RF1167" manufactured by Ube Industries, Ltd.) containing 2% by weight of an antibacterial agent ("Amenitop" manufactured by Matsushita Electric Industrial Co., Ltd.) was used as a core material 10.
A polypropylene resin (the same as above) to which no antibacterial agent was added was used as each. And 2 cylinders 6a, 6
b, a three-layer injection molding machine 3 including one nozzle 7 and a molding die 4 in which a gate 8 is provided at the center of a cavity 5 having a volume of 200 cm ^{3 and which} is formed for bowl formation, Molding was performed as in 2 (a) (b) (c) to obtain tableware A having a three-layer structure in which the weight ratio of the skin layer 1 and the core layer 2 was 50:50. The molding conditions at this time were: injection time: 10 seconds, cooling time: 120 seconds, injection pressure: 200 kg /
cm ² , the temperature of the molding die 4 was 40 ° C, the temperature of the cylinder 6a was 200 ° C, and the temperature of the cylinder 6b was 200 ° C.

(Example 2) A polypropylene resin containing the same antibacterial agent as in Example 1 was used as the skin material 9, a polypropylene resin which was reused for the second time was used as the core material 10, and the rest was molded in the same manner as in Example 1. A table A having a three-layer structure in which the weight ratio of the skin layer 1 and the core layer 2 was 55:45 was obtained.

(Example 3) Ethylene propylene copolymer resin (EP resin; "Toughmer P08" manufactured by Mitsui Petrochemical Co., Ltd.)
80) 20 parts by weight and about 140 parts by weight of high-density polyethylene (HDPE; "BZ50U" manufactured by Mitsubishi Chemical Industry Co., Ltd.)
Liquid paraffin as a heat storage material (“Liquid paraffin 155” manufactured by Nippon Seiro Co., Ltd .; melting point 69)
C.) 70 parts by weight were added and mixed uniformly, and the mixture was extruded with a uniaxial extruder, cooled with water, drained and granulated with a pelletizer to prepare a core material 10 containing a heat storage material.

The core material 10 and the polypropylene material containing the same antibacterial agent as in Example 1 were used as the skin material 9, and the molding was performed in the same manner as in Example 1 except that the weight ratio of the skin layer 1 to the core layer 2 was 60. : 40 pieces of tableware A having a three-layer structure was obtained. The molding conditions were: injection time: 10 seconds, cooling time: 120 seconds, injection pressure: 200 kg / cm ² , molding die 4 temperature: 40 ° C., cylinder 6a temperature: 200 ° C., cylinder 6b temperature: 150 ° C. It was

(Comparative Example 1) A polypropylene resin (“RF1167” manufactured by Ube Industries, Ltd.) containing no antibacterial agent and having a volume of 20 was used by using an injection molding machine having one cylinder and one nozzle.
0 cm ³ single-layer tableware (rice bowl) was molded. The conditions for this molding are: injection time 10 seconds, cooling time 120 seconds,
The injection pressure was 200 kg / cm ² , the mold temperature was 40 ° C., and the cylinder temperature was 200 ° C.

(Comparative Example 2) Tableware having a one-layer structure was formed in the same manner as in Comparative Example 1 except that polypropylene resin containing 2% by weight of the same antibacterial agent as in Example 1 was used. (Comparative Example 3) Tableware having a one-layer structure was molded in the same manner as in Comparative Example 1 except that polypropylene resin containing 1% by weight of the same antibacterial agent as in Example 1 was used.

Examples 1 to 3 obtained as described above
The antibacterial effect of the tableware of Comparative Examples 1 to 3 was tested. The test was carried out by allowing E. coli having a concentration of 10 ⁴ cfu / ml to stand still on the concave surface of the dish and allowing it to stand in an atmosphere having a temperature of 37 ° C. and a humidity of 90% for 24 hours and measuring the E. coli concentration. Table 1 shows the results.

[0024]

[Table 1]

As shown in Table 1, in each of the examples, even if the ratio of the antibacterial agent to the whole tableware is about 1% by weight, the surface portion should contain the antibacterial agent at a density of 2% by weight. It is confirmed that a high antibacterial effect can be obtained.
On the other hand, in Comparative Example 3, when the ratio of the antibacterial agent to the entire tableware is 1% by weight, the antibacterial effect is insufficient,
In order to obtain a high antibacterial effect, the ratio of the antibacterial agent to the whole tableware needs to be 2% by weight as in Comparative Example 2.

[0026]

As described above, the tableware according to the present invention is characterized by comprising an antibacterial agent in the skin layer in the tableware comprising the surface skin layer and the inner core layer. Even if the content of the antibacterial agent with respect to the whole tableware is reduced, the skin layer can contain an amount of the antibacterial agent that can sufficiently obtain the antibacterial effect. The addition amount can be reduced.

The invention according to claim 2 is characterized in that the core layer is made of the same material as the skin layer containing no antibacterial agent, and the core layer and the skin layer are made of the same resin. The tableware can be formed into a substantially single-layered structure, and problems such as delamination can be eliminated.
The invention according to claim 3 is characterized in that the core layer is formed of a recycled material, and the cost can be reduced and the effect of resource saving can be obtained with an inexpensive recycled material. It is possible.

The invention according to claim 4 is characterized in that the core layer is formed of a heat storage material, and heat retention performance or cold insulation performance can be obtained by heat storage by the heat storage material,
It is possible to obtain tableware excellent in heat retention and cold retention. A method of manufacturing tableware according to the present invention includes a 2 cylinder,
Using a three-layer injection molding machine consisting of one nozzle, the skin material containing the antibacterial agent was first injected from one cylinder into the cavity of the molding die, and then the core material was injected from the other cylinder, and then By injecting a skin material mixed with an antibacterial agent from one of the cylinders, a skin layer of the skin material is formed into a table having a three-layer structure in which the core layer of the core material is wrapped. It is injected into the cavity so as to immerse into the skin material that has been previously injected into the cavity, and molding can be performed by wrapping the core layer of the core material with the skin layer of the skin material, The tableware can be produced without the need to bond the skin layer and the core layer in the later step, and the tableware can be produced in one step of injection molding. Than it is.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of tableware according to the present invention.

FIG. 2 shows an embodiment of a method for manufacturing tableware according to the present invention, in which (a), (b) and (c) are sectional views, respectively.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Skin layer 2 Core layer 3 Injection molding machine for three-layer molding 4 Mold 5 Cavity 6a Cylinder 6b Cylinder 7 Nozzle 9 Skin material 10 Core material

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08K 3/22 KAE C08K 3/22 KAE C08L 101/00 C08L 101/00 // B29L 31:00

Claims (5)

[Claims] 1. A tableware comprising a surface skin layer and an inner core layer, wherein the skin layer contains an antibacterial agent. 2. The core layer is formed of the same material as the skin layer containing no antibacterial agent.
Tableware described in. 3. The tableware according to claim 1, wherein the core layer is made of a recycled material. 4. The tableware according to claim 1, wherein the core layer is made of a heat storage material. 5. A two-cylinder, one-nozzle injection molding machine for three-layer molding is used to first inject a skin material containing an antibacterial agent into the cavity of a molding die from one cylinder and then from the other cylinder. By injecting the core material, and then injecting the skin material mixed with the antibacterial agent from the cylinder on one side, it is possible to form a three-layer tableware in which the core layer of the core material is wrapped with the skin layer of the skin material. Characteristic tableware manufacturing method.