JP2022125544A - Antimicrobial resin molded product and its manufacturing method - Google Patents

Abstract

To provide a manufacturing method for an antimicrobial resin molded product in which either inorganic or organic antimicrobial agents can be used, and in which a utilization efficiency of the antimicrobial agent is increased.SOLUTION: A manufacturing method for an antimicrobial resin molded product includes: pouring a thermoplastic resin R1 into a first cavity C1 formed by closing an upper mold 10 and a first lower mold 20; molding a main body part 2 by cooling and solidifying the thermoplastic resin R1 in the upper mold 10 and the first lower mold 20; opening the upper mold 10 and the first lower mold 20 while the upper mold 10 holds the body main part 2; replacing the first lower mold 20 with a second lower mold 30 that is cooler than a temperature of the main body part 2 held in the upper mold 10; pouring an urethane resin material R2 into a second cavity C2 formed by closing the upper mold 10 and the second lower mold 30; and molding an antimicrobial layer 3 by curing the urethane resin material R2.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to an antibacterial resin molded article and a method for producing the same.

An antibacterial resin molded product containing an antibacterial agent is known from Patent Document 1 and the like.

Japanese Patent Laid-Open No. 9-216563

By the way, the above patent document describes a method of manufacturing an antibacterial resin molded article by forming an antibacterial layer in advance on the cavity surface of a mold and then pouring a resin into the mold. In this case, the antibacterial layer formed on the mold cavity surface may flow and come off when the resin is poured.
Further, other antibacterial resin molded articles are often formed by injection molding using a resin containing an antibacterial agent. However, in such a method, only the antibacterial agent exposed on the surface contributes to the antibacterial property, but the antibacterial agent embedded in the resin does not contribute to the antibacterial property, and there is a large amount of the antibacterial agent that does not participate in the antibacterial action. become. Therefore, the utilization efficiency of the antibacterial agent is poor.
Further, organic antibacterial agents cannot be used because they are degraded by heat during injection molding.

SUMMARY OF THE INVENTION An object of the present invention is to provide an antibacterial resin molded article which can use both inorganic and organic antibacterial agents and which has improved utilization efficiency of the antibacterial agent, and a method for producing the same.

According to one aspect of the invention,
A method for producing an antibacterial resin molded article having a main body made of a thermoplastic resin and an antibacterial layer provided on at least a part of the surface of the main body, comprising:
closing the upper mold and the first lower mold that open and close vertically to form a first cavity for forming the main body, pouring a thermoplastic resin into the first cavity,
cooling and solidifying the thermoplastic resin in the closed upper mold and the first lower mold to mold the main body;
opening the upper mold and the first lower mold while holding the main body in the upper mold;
replacing the first lower mold with a second lower mold whose temperature is lower than the temperature of the main body held by the upper mold;
closing the upper mold and the second lower mold to form a second cavity for forming the antibacterial layer between the main body and the second lower mold;
pouring a liquid urethane resin raw material containing an inorganic or organic antibacterial agent into the second cavity;
A method for producing an antibacterial resin molded product is provided, comprising heating the second lower mold to cure the urethane resin raw material to form the antibacterial layer.

In the production method of the present invention described above,
The specific gravity of the antibacterial agent may be higher than the specific gravity of the urethane resin raw material.

In the production method of the present invention described above,
The urethane resin raw material may be of a two-liquid type in which two kinds of liquids are mixed and then poured into the second cavity.

In the production method of the present invention described above,
The viscosity of the urethane resin raw material poured into the second cavity may be 20 mPa·s or more and less than 150 mPa·s.

In the production method of the present invention described above,
A curing time for curing the antibacterial layer may be longer than a cooling time of the body portion within the first cavity.

In the production method of the present invention described above,
The urethane resin raw material containing the antibacterial agent may be stirred in a tank storing the urethane resin raw material before being poured into the second cavity.

In the production method of the present invention described above,
The thermoplastic resin may be ABS (acrylonitrile-butadiene-styrene) resin or PC-ABS (polycarbonate ABS) resin.

According to one aspect of the invention,
a main body made of thermoplastic resin;
An antibacterial resin molded article having an antibacterial layer provided on at least part of the surface of the main body,
The antibacterial layer is composed of a urethane resin containing an inorganic or organic antibacterial agent,
The average particle size of the antibacterial agent is 1/1000 or more and less than 1/5 of the thickness of the antibacterial layer,
An antibacterial resin molded product is provided in which the concentration of the antibacterial agent in the surface layer of the antibacterial layer is higher than the concentration of the antibacterial agent in the central portion in the thickness direction of the antibacterial layer.

In the antibacterial resin molded article of the present invention described above,
The antibacterial layer may have a thickness of 50 μm or more.

In the antibacterial resin molded article of the present invention described above,
The average particle size of the antibacterial agent may be 5 μm or more.

In the antibacterial resin molded article of the present invention described above,
The thermoplastic resin may be ABS (acrylonitrile-butadiene-styrene) resin or PC-ABS (polycarbonate ABS) resin.

INDUSTRIAL APPLICABILITY According to the present invention, an antibacterial resin molded product which can use both inorganic and organic antibacterial agents and which has improved utilization efficiency of the antibacterial agent and a method for producing the same are provided.

1 is a cross-sectional view of an antibacterial resin molded product according to the present invention; FIG. It is a schematic diagram which shows the state which closed the upper mold|type and the 1st lower mold|type, and formed the 1st cavity. It is a schematic diagram which shows a mode that a main-body part is shape|molded by pouring a thermoplastic resin into a 1st cavity. FIG. 4 is a schematic diagram showing how the upper mold and the first lower mold are opened while the main body is held by the upper mold. It is a schematic diagram which shows a mode that a 1st lower mold and a 2nd lower mold are exchanged. FIG. 4 is a schematic diagram showing how a urethane resin raw material is poured into a second cavity formed by an upper mold and a second lower mold; FIG. 4 is a schematic diagram showing how a urethane resin raw material is cured to form an antibacterial layer. FIG. 4 is a diagram showing how a liquid urethane resin raw material containing an antibacterial agent is poured into the second cavity.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described based on embodiments with reference to the drawings. The same or equivalent constituent elements, members, and processes shown in each drawing are denoted by the same reference numerals, and duplication of description will be omitted as appropriate. Moreover, the embodiments are illustrative rather than limiting the invention, and not all features and combinations thereof described in the embodiments are necessarily essential to the invention.

FIG. 1 is a cross-sectional view of an antibacterial resin molded article 1 according to an embodiment of the present invention. As shown in FIG. 1, the antibacterial resin molded product 1 has a main body 2 made of thermoplastic resin and an antibacterial layer 3 provided on at least part of the surface of the main body 2 . The main body 2 is made of thermoplastic resin such as ABS (acrylonitrile-butadiene-styrene) resin or PC-ABS (polycarbonate ABS) resin. The thickness T of the antibacterial layer 3 is preferably 50 μm or more.

The antibacterial layer 3 is made of urethane resin containing an inorganic or organic antibacterial agent 4 (see FIG. 8). As the antibacterial agent 4, a particulate antibacterial agent 4 can be used. The average particle size of the antibacterial agent 4 is preferably 5 μm or more. The average particle size can be obtained as a volume average particle size (D50) using a laser scattering diffraction method particle size distribution analyzer.

As the particulate antibacterial agent 4, for example, an inorganic antibacterial agent such as a silver-supported inorganic antibacterial agent or a copper-supported inorganic antibacterial agent can be used. For example, the following can be employed as inorganic antibacterial agents.
silver-supporting inorganic antibacterial agents and copper-supporting inorganic antibacterial agents using phosphates such as zirconia phosphate, aluminum phosphate, hydroxyapatite, and calcium phosphate as carriers;
Silver-supported inorganic antibacterial agents and copper-supported inorganic antibacterial agents using silicates such as zeolite and silica gel as carriers,
Silver-supported inorganic antibacterial agents and copper-supported inorganic antibacterial agents using glass, activated carbon, carbon fiber, etc. as carriers

Alternatively, the following can be employed as organic antibacterial agents.
Aldehyde antibacterial agents such as α-bromocinnamaldehyde Carboxylic acid antibacterial agents such as sodium benzoate Phenolic antibacterial agents such as 2-benzyl-4-chlorophenol 3-Iodo-2-propylbutylcarbamate and other agents Organic iodine-based antibacterial agents Pentsuimidazole-based antibacterial agents such as 2-(4-thiazolyl)pentimidazole Isothiazoline-based antibacterial agents such as 2-n-octyl-4-isothiazolin-3-one 2,4,5,6 - Nitrile antibacterial agents such as tetrachloroisophthalonitrile Pyridine antibacterial agents such as 2,3,5,6-tetrachloro-4-(methylsulfonyl)pyridine N,N',N"-trishydroxyethylhexahydro -Triazine antibacterial agents such as s-triazine N-haloalkylthio antibacterial agents such as N-(fluorodichloromethylthio)phthalimide Quaternary ammonium salt antibacterial agents such as didecyldimethylammonium chloride Bis(pyridine-2- Pyrithione-based antibacterial agents such as thiol-l-oxide) zinc salts Organic copper-based antibacterial agents such as 8-oxyquinoline copper Organic arsenic-based antibacterial agents such as 10,10'-oxybisphenoxaarsine Wasabi, mustard, cypress Plant-derived organic antibacterial agents such as

Next, a method for manufacturing the antibacterial resin molded product 1 will be described with reference to FIGS. 2 to 8. FIG.
First, as shown in FIG. 2, the upper mold 10 and the first lower mold 20 are closed to form the first cavity C1 for forming the main body portion 2 . The upper mold 10 and the first lower mold 20 are vertically movable relative to each other. Here, it is assumed that the upper mold 10 does not move vertically and the first lower mold 20 can move vertically.

Next, as shown in FIG. 3, a molten thermoplastic resin R1 is poured into the first cavity C1 formed by the upper mold 10 and the first lower mold 20. Then, as shown in FIG. After filling the first cavity C1 with the thermoplastic resin R1, the upper mold 10 and/or the first lower mold 20 are cooled to cool and solidify the thermoplastic resin R1, thereby molding the main body portion 2.

Next, as shown in FIG. 4 , the upper mold 10 and the first lower mold 20 are opened while holding the main body 2 on the upper mold 10 . Here, the main body part 2 is attached to the upper mold 10 by cooling the main body part 2 and shrinking the main body part 2 more than the upper mold 10 .

Note that the method of holding the body portion 2 on the upper mold 10 is not limited to this example. The main body part 2 may be provided with a protruding part that protrudes toward the upper mold 10 for preventing separation in the direction of the first lower mold 20 . Alternatively, the upper mold 10 may be provided with a protruding portion projecting toward the first cavity C1 for preventing the main body portion 2 from detaching toward the first lower mold 20 . Alternatively, such a projecting portion provided on the upper mold 10 may be configured by a movable pin capable of advancing into the first cavity C1.

FIG. 5 is a schematic diagram showing how the first lower mold 20 and the second lower mold 30 are exchanged. As shown in FIG. 5, the first lower mold 20 is replaced with a second lower mold 30 set to a temperature lower than the temperature of the main body 2 held by the upper mold 10 . Here, the upper mold 10 is moved in the left-right direction to above the cooled second lower mold 30 . The second lower mold 30 is kept at a temperature lower than that of the main body 2 by water cooling or air cooling.
Note that setting the second lower mold 30 to a lower temperature than the temperature of the main body 2 held by the upper mold 10 means that the temperature obtained by measuring the main body 2 held by the upper mold 10 at the time of mold opening is The temperature of the second lower mold 30 may be set so that the cavity surface of the second lower mold 30 is at a low temperature. Alternatively, the temperature of the main body 2 held by the upper mold 10 at the time of mold opening is experimentally confirmed in advance, and the temperature of the second lower mold 30 may be set to be equal to or lower than this temperature. Alternatively, since the temperature of the main body 2 is higher than the temperature of the upper mold 10 when the mold is opened, the temperature of the second lower mold 30 may be set to the temperature of the upper mold 10 or less.

Next, as shown in FIG. 6, the upper mold 10 and the second lower mold 30 are closed, and a second mold for forming the antibacterial layer 3 is placed between the main body 2 and the second lower mold 30. A cavity C2 is formed. The cavity formed by the upper mold 10 and the second lower mold 30 includes a space for accommodating the body part 2 and a second cavity C2 for forming the antibacterial layer 3 . Therefore, the cavity formed by the upper mold 10 and the second lower mold 30 is larger than the first cavity C1 for forming the body portion 2 .

Next, as shown in FIG. 7, a liquid urethane resin raw material R2 containing the antibacterial agent 4 is poured into the second cavity C2. Further, the second lower mold 30 is heated to react and harden the urethane resin raw material R2 to form the antibacterial layer 3 . Thus, the antibacterial resin molded product 1 having the antibacterial layer 3 provided on at least part of the surface of the main body 2 is formed.

According to the manufacturing method of this embodiment, the body portion 2 and the antibacterial layer 3 are cured in separate steps. The curing temperature of the urethane resin raw material R2 forming the antibacterial layer 3 is 100° C. or lower, which is lower than the heat-resistant temperature at which the antibacterial effect of the organic antibacterial agent 4 is lost. Therefore, when the urethane resin raw material R2 is cured to form the antibacterial layer 3, the antibacterial effect of the organic antibacterial agent 4 can be maintained.

FIG. 8 is a diagram showing how the liquid urethane resin raw material R2 containing the antibacterial agent 4 is poured into the second cavity C2. Since resistance to the fluid flowing through the second cavity C2 is greater near the cavity surface 31 than at the center in the thickness direction of the second cavity C2, the flow velocity becomes lower. When the urethane resin raw material R2 flows through the second cavity C2, the particulate antibacterial agent 4 is less likely to stay in the center of the thickness direction of the second cavity C2 due to the fountain flow phenomenon at the flow front, It becomes easy to accumulate. For this reason, in the antibacterial resin molded product 1 obtained by the manufacturing method of the present embodiment, the concentration of the antibacterial agent 4 in the surface layer of the antibacterial layer 3 is higher than the concentration of 4. Therefore, the antibacterial agent 4 is easily exposed on the surface of the antibacterial layer 3, and the utilization efficiency of the antibacterial agent 4 is enhanced.
The average particle size of the antibacterial agent 4 is preferably 1/1000 or more and 1/5 of the thickness of the antibacterial layer 3 . If the average particle size of the antibacterial agent 4 is less than 1/1000, the antibacterial agent 4 becomes difficult to disperse in the urethane resin raw material R. If the average particle size of the antibacterial agent 4 is more than 1/5, the antibacterial agent 4 is difficult to be carried in the second cavity C2 by the urethane resin raw material R2.

Further, the specific gravity of the antibacterial agent 4 is preferably higher than the specific gravity of the urethane resin raw material R2. If the specific gravity of the antibacterial agent 4 is greater than the specific gravity of the urethane resin raw material R2, in the step of forming the antibacterial layer 3, the antibacterial agent 4 is applied to the cavity surface 31 of the second lower mold 30 constituting the lower surface of the second cavity C2. Easy to accumulate. Therefore, it becomes easier to position the antibacterial agent 4 on the surface of the antibacterial layer 3 . The specific gravity of the antibacterial agent 4 is preferably 1.5 times or more the specific gravity of the urethane resin raw material R2. More preferably, the specific gravity of the antibacterial agent 4 is at least twice the specific gravity of the urethane resin raw material R2.

Further, the urethane resin raw material R2 is preferably of a two-liquid type in which two kinds of liquids are mixed and then poured into the second cavity C2. For the two-liquid type urethane resin raw material R2, the curing speed of the urethane resin raw material R2 can be adjusted by adjusting the mixing ratio of the two types of liquids. Therefore, the curing speed can be adjusted so that the urethane resin raw material R2 is cured after the antibacterial agent 4 moves in the urethane resin raw material R2 so that the antibacterial agent 4 is exposed to the surface.

The viscosity of the urethane resin raw material R2 to be poured into the second cavity C2 is preferably 20 mPa·s or more and less than 150 mPa·s. If the viscosity of the urethane resin raw material R2 is less than 20 mPa·s, even if the urethane resin raw material R2 containing the antibacterial agent 4 is stirred, the antibacterial agent 4 immediately settles in the tank 32, and the urethane resin raw material R2 that is poured into the tank 32 is hardened. The concentration of the antibacterial agent 4 varies, and the antibacterial agent 4 tends to be concentrated in the antibacterial layer 3. - 特許庁If the viscosity of the urethane resin raw material R2 is more than 150 mPa·s, it becomes difficult for the urethane resin raw material R2 to flow through the second cavity C2. In addition, the antibacterial agent 4 is less likely to mix with the urethane resin raw material R2. Furthermore, it becomes difficult for the antibacterial agent 4 to settle within the second cavity C2.

It is preferable that the curing time for curing the antibacterial layer 3 in the process shown in FIG. 7 is longer than the cooling time of the main body 2 in the first cavity C1 in the process shown in FIG. This is because the longer the curing time of the antibacterial layer 3 is, the easier it is to secure the time for the antibacterial agent 4 to migrate (settle) in the urethane resin raw material R2.

In addition, it is preferable to pour the urethane resin raw material R2 into the second cavity C2 in a state in which the particulate antibacterial agent 4 is dispersed as evenly as possible in the urethane resin raw material R2. Therefore, it is preferable to stir the urethane resin raw material R2 containing the antibacterial agent 4 in the tank 32 (see FIG. 6) that stores the urethane resin raw material R2 before pouring it into the second cavity C2.

In the case of continuously manufacturing the antibacterial resin molded product 1, the mold is opened from the state shown in FIG. After moving above the first lower mold 20, the cooling of the second lower mold 30 is started to prepare for the process shown in FIG.

Further, in the above description, an example was described in which the upper mold 10 can move in the horizontal direction and the first lower mold 20 and the second lower mold 30 can move in the vertical direction, but the present invention is limited to this. can't The upper mold 10 can move in the horizontal direction and the vertical direction, and the first lower mold 20 and the second lower mold 30 may be fixed. Alternatively, the upper mold 10 may be fixed, and the first lower mold 20 and the second lower mold 30 may be movable in the horizontal direction and the vertical direction.

It should be noted that the present invention is not limited to the above-described embodiments, and can be modified, improved, etc. as appropriate.
In addition, the material, shape, size, numerical value, form, number, location, etc. of each component in the above-described embodiment are arbitrary and not limited as long as the present invention can be achieved.

1 Antibacterial resin molded product 2 Main body 3 Antibacterial layer 4 Antibacterial agent 10 Upper mold 20 First lower mold 30 Second lower mold 31 Cavity surface 32 Tank C1 (for storing urethane resin raw material) First cavity C2 Second cavity R1 Thermoplastic resin R2 Urethane resin raw material

Claims (11)

A method for producing an antibacterial resin molded article having a main body made of a thermoplastic resin and an antibacterial layer provided on at least a part of the surface of the main body, comprising:
closing the upper mold and the first lower mold that open and close vertically to form a first cavity for forming the main body, pouring a thermoplastic resin into the first cavity,
cooling and solidifying the thermoplastic resin in the closed upper mold and the first lower mold to mold the main body;
opening the upper mold and the first lower mold while holding the main body in the upper mold;
replacing the first lower mold with a second lower mold whose temperature is lower than the temperature of the main body held by the upper mold;
closing the upper mold and the second lower mold to form a second cavity for forming the antibacterial layer between the main body and the second lower mold;
pouring a liquid urethane resin raw material containing an inorganic or organic antibacterial agent into the second cavity;
A method for producing an antibacterial resin molded article, wherein the second lower mold is heated to cure the urethane resin raw material to form the antibacterial layer. 2. The method for producing an antibacterial resin molded article according to claim 1, wherein the specific gravity of said antibacterial agent is higher than the specific gravity of said urethane resin raw material. 2. The method for producing an antibacterial resin molded article according to claim 1, wherein said urethane resin raw material is of a two-liquid type in which two kinds of liquids are mixed and then poured into said second cavity. 2. The method for producing an antibacterial resin molded article according to claim 1, wherein the viscosity of said urethane resin raw material poured into said second cavity is 20 mPa.s or more and less than 150 mPa.s. 2. The method of manufacturing an antibacterial resin molded product according to claim 1, wherein the curing time for curing the antibacterial layer is longer than the cooling time of the main body in the first cavity. 2. The method for producing an antibacterial resin molded article according to claim 1, wherein the urethane resin raw material containing the antibacterial agent is stirred in a tank for storing the urethane resin raw material before pouring into the second cavity. 2. The method for producing an antibacterial resin molded product according to claim 1, wherein said thermoplastic resin is ABS (acrylonitrile-butadiene-styrene) resin or PC-ABS (polycarbonate ABS) resin. a main body made of thermoplastic resin;
An antibacterial resin molded article having an antibacterial layer provided on at least part of the surface of the main body,
The antibacterial layer is composed of a urethane resin containing an inorganic or organic antibacterial agent,
The average particle size of the antibacterial agent is 1/1000 or more and less than 1/5 of the thickness of the antibacterial layer,
An antibacterial resin molded article, wherein the concentration of the antibacterial agent in the surface layer of the antibacterial layer is higher than the concentration of the antibacterial agent in the central portion in the thickness direction of the antibacterial layer. The antibacterial resin molded product according to claim 8, wherein the antibacterial layer has a thickness of 50 µm or more. 9. The antibacterial resin molded article according to claim 8, wherein the antibacterial agent has an average particle size of 5 μm or more. 9. The antibacterial resin molded article according to claim 8, wherein said thermoplastic resin is ABS (acrylonitrile-butadiene-styrene) resin or PC-ABS (polycarbonate ABS) resin.

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