Method for producing resin molded body for pest control

Abstract

To prevent the occurrence of short shots when manufacturing resin molded bodies for pest control by injection molding.SOLUTION: In a method for manufacturing, by injection molding, a resin molded body for pest control, comprising an outer frame 1, a plurality of reinforcing members 2 inside the outer frame and a plurality of square members 3 having at least a partially three-dimensional curved portion inside the outer frame, when the sum of the lengths of the outer frame, the square members and the reinforcing members is a (cm), the number of gates provided in the mold used is b (number of gates), and the logarithm of the melt flow rate (g / 10 min) measured at a load of 2.16 kgf and a test temperature of 190°C based on JISK7210 for the resin composition is c in the ordinary logarithm, (formula) a / (b×c)≤100 is satisfied and the resin is injection-molded in the mold (the melt flow rate of the resin composition is 1 to 50 g / 10 min.).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a pest control resin molded article. [Background technology]

[0002] It is known that pest control devices are installed in houses to prevent pests from entering through windows, entrances, etc. As an example of such a pest control device, a three-dimensional pest control resin molded body containing a room temperature volatile pest control agent and having an opening has been proposed (see Patent Documents 1 to 3).

[0003] These three-dimensional pest control resin moldings can have excellent insect control effects by, for example, reducing the diameter of the outer frame or timber components of the moldings, or by increasing the volume of the space in the pest control resin moldings, thereby enhancing the volatilization effect of the volatile insecticide. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-131117 A [Patent Document 2] JP 2016-123390 A [Patent Document 3] JP 2014-73089 A Summary of the Invention [Problem to be solved by the invention]

[0005] When a three-dimensional pest control resin molded article having a complex shape as described above is produced by injection molding, a defect called a shortcut, such as a defect occurring in part of the intended molded article, is likely to occur.

[0006] Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a method for easily producing a pest control resin molded article. [Means for solving the problem]

[0007] The present invention relates to a method for manufacturing a pest control resin molded body by injection molding, the pest control resin molded body including an outer frame body, a plurality of reinforcing members arranged inside the outer frame body, and a plurality of rectangular timbers having at least a three-dimensional curved portion arranged inside the outer frame body, the method comprising the steps of: After filling a resin composition containing a volatile insect repellent and a resin into an injection molding machine, When the total length of the outer frame, the square bar, and the reinforcing member is a (cm), the number of gates provided in the mold used in the injection molding is b (pieces), and the logarithm of the melt flow rate (g / 10 min) of the resin composition measured at a load of 2.16 kgf and a test temperature of 190° C. based on JIS K7210 is c, (Formula) a / (b×c)≦100 The above-mentioned problems are solved by a method for producing a pest control resin molded article, which is characterized by satisfying the above-mentioned requirements and carrying out injection molding into the mold. Effect of the Invention

[0008] According to the present invention, it is possible to prevent the occurrence of short shots when the pest control resin molded article is produced by injection molding. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing an example of a pest control resin molded body. [Diagram 2] A front view showing an example of a resin molded body for pest control. [Diagram 3] Diagram showing an example of square timber DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In the pest control resin molded article according to the present invention, the volatile insecticide used is transfluthrin (vapor pressure (25°C) 3.5 x 10 -3 Pa), Metofluthrin (vapor pressure (25°C) 1.8 x 10 -4Examples of pyrethroid compounds include pyrethroid compounds such as empenthrin (vapor pressure (25°C) 0.02 Pa), empenthrin (vapor pressure (25°C) 0.02 Pa), and profluthrin (vapor pressure (25°C) 0.01 Pa). These pyrethroid compounds exist as various optical isomers or geometric isomers, and any of these isomers can be used. These pyrethroid compounds can be used alone or in combination of two or more kinds.

[0011] The content of the volatile insect repellent is appropriately determined depending on the use environment, period of use, etc., but is usually in the range of 1 to 20% by weight based on the total amount of the resin composition.

[0012] The resin used in the present invention is not particularly limited as long as it can efficiently support the volatile insect repellent and further allows the supported volatile insect repellent to gradually volatilize from the surface of the pest control resin molded body of the present invention. Examples of the resin include polyolefin resins such as polyethylene resins and polypropylene resins, copolymers of polyolefin resins with carboxylic acid esters such as methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinyl acetate, and polymer blends of polyolefin resins with copolymers.

[0013] Among these resins, from the viewpoint of the volatility of the volatile insect repellent, it is preferable that the copolymer of polyolefin resin and carboxylic acid ester includes an ethylene-methacrylic acid copolymer or an ethylene-vinyl acetate copolymer in which the carboxylic acid ester is blended at 1 to 35% by weight relative to the polyolefin resin, and it is more preferable to use a polymer blend of a polyethylene resin with these copolymers.

[0014] In addition to the volatile insecticide and the resin, the resin composition of the present invention may contain a fine powder carrier such as talc, alumina, silica, white carbon (microcrystalline silica or fine powdered silicic acid), diatomaceous earth, zeolites, clay minerals, wood powder, etc., in order to adjust the volatilization rate of the volatile insecticide from the surface of the pest control resin molding.

[0015] The resin composition may contain synergists, antibacterial agents, antifungal agents, fragrances / deodorants, flavorings, colorants, antistatic agents, antioxidants, ultraviolet absorption inhibitors, and crystal precipitation inhibitors.

[0016] From the viewpoint of productivity, the resin composition is prepared by melt-kneading the respective raw materials in a known kneader such as a pressure kneader, extruding the mixture into pellets, and then feeding the pellets into an injection molding machine.

[0017] The resin composition is adjusted so that its melt flow rate (MFR), measured according to JIS K7210 at a load of 2.16 kgf and a test temperature of 190° C., is preferably 1 to 50 g / 10 min, more preferably 3 to 40 g / 10 min. When the MFR is within this range, the resin composition can be smoothly poured into a mold during injection molding, and the cooling time of the mold after injection molding can be shortened.

[0018] The pest control resin molded body of the present invention comprises an outer frame 1, a plurality of reinforcing members 2 arranged inside the outer frame, and a plurality of rectangular timbers 3 having three-dimensional curved portions at least in part arranged inside the outer frame. Examples of the pest control resin molded body include pest control resin molded bodies as shown in Figures 1 to 3. However, the pest control resin molded body is not limited to these examples.

[0019] The thickness of the outer frame 1, the reinforcing member 2, and the square members 3 is preferably in the range of 0.1 to 3 mm from the viewpoint of the volatility of the volatile insect repellent.

[0020] The width of the outer frame 1, the reinforcing member 2, and the square timber 3 is preferably in the range of 0.1 to 3 mm from the viewpoint of the volatility of the volatile insect repellent.

[0021] The height 31 of the three-dimensional curved portion of the square timber 3 is preferably in the range of 2 to 20 times the thickness of the square timber from the viewpoint of the volatility of the volatile insect repellent. Also, it is preferable that one square timber intersects with another square timber in order to increase the volatility of the volatile insect repellent from the surface of the resin molded body.

[0022] The total area of ​​the openings 4 in the pest control resin molded body is preferably in the range of 40 to 85% of the total surface area of ​​the pest control molded body, and more preferably 50 to 75%, from the viewpoint of the volatility of the volatile insecticide.

[0023] The total length a (cm) of the outer frame 1, the reinforcing member 2, and the square bar 3 is appropriately designed depending on the usage environment, period of use, resin strength, etc., but is preferably in the range of 100 to 15,000 cm, and more preferably 100 to 10,000 cm.

[0024] The pest control resin molded body of the present invention is manufactured by a known injection molding method, which, for example, includes a step of melting the resin composition in the cylinder of an injection molding machine, and then injecting the resin composition into a cavity in a mold through a gate provided in the mold to obtain the pest control resin molded body.

[0025] Examples of the gate provided in the mold used in the present invention include a direct gate, a side gate, a pin gate, a film gate, a valve gate, etc. With regard to the diameter of the gate, the diameter φ is preferably 0.2 to 1.0 mm, more preferably 0.3 to 0.8 mm, from the viewpoint of productivity. The number of the gates is set so as to satisfy the manufacturing method of the present invention, based on the total of the outer frame, the squared material, and the reinforcing member of the pest control resin molded body, the shape of the molded body, and the logarithm of the melt flow rate of the resin composition used.

[0026] The temperature inside the cylinder of the injection molding machine is set to 160 to 220° C. If it is lower than 160° C., molding defects (short shots) occur, such as the molten resin composition not being able to reach the end of the mold, and if it is higher than 220° C., the room temperature volatile insect repellent may decompose.

[0027] The mold temperature during injection molding is 150 to 200° C., and preferably 160 to 190° C. The injection pressure of the resin composition into the mold is 100 to 300 MPa, and preferably 150 to 250 MPa. After a predetermined amount of the resin composition is injected into the mold cavity, the pressure is maintained for about 1 to 5 seconds, and then the mold is cooled and molded, and the mold is opened to obtain a pest control resin molded article.

[0028] The pest control resin molded article thus obtained is used while being stored in a container having an opening, since there is a risk that the volatile insecticide will volatilize from the surface and come into contact with hands.

[0029] The resin molded article for pest control exhibits an excellent control effect against arthropods including many insects, particularly flying pests, specifically, mosquitoes such as Culex pipiens, Culex pipiens molestus, and Aedes albopictus, black flies, midges, flies, moths, and the like. EXAMPLES

[0030] Hereinafter, the present embodiment will be described with reference to specific examples and comparative examples, but the present embodiment is not limited to the examples described below.

[0031] In measuring the melt flow rate, the resin compositions produced in the examples and comparative examples described later were finely crushed with nippers to prepare measurement samples, and the measurements were performed at a load of 2.16 kgf and a test temperature of 190° C. according to JIS K7210. EXAMPLES

[0032] 90 parts by weight of ethylene-methyl methacrylate copolymer (ratio of methyl methacrylate in the copolymer: 20% by weight, trade name: Acryft WH206, manufactured by Sumitomo Chemical Co., Ltd.) and 10 parts by weight of 2,3,5,6-tetrafluoro-4-methoxymethylbenzyl (1R)-trans-2,2-dimethyl-3-[(Z)-1-propenyl]cyclopropanecarboxylate (Metofluthrin, trade name: Eminence, manufactured by Sumitomo Chemical Co., Ltd.) were melt-kneaded at 200°C using an internal pressure kneader (manufactured by Moriyama Seisakusho Co., Ltd.), and the kneaded product obtained was hot-cut while being extruded from the extruder to obtain a pellet-shaped resin composition. The melt flow rate of this resin composition was 4.0. Next, the resin molding for pest control was designed to have an elliptical shape with a long diameter of 135 mm and a short diameter of 105 mm as shown in Figure 1, with the outer frame 1 having a thickness of 1 mm and a width of 1 mm, the reinforcing member 2 having a thickness of 3 mm and a width of 2 mm, and the beam 3 having a thickness of 1 mm, a width of 1 mm and a height 31 of 3 mm, with curved parts, so that the total length (a) of the outer frame, reinforcing member and beam of the resin molding for pest control was 520 cm. The pellet-shaped resin composition was melted at 190°C in an injection molding machine, and the resin was injected into the mold at a pressure of 200 MPa, with 9 gates (b) and a gate diameter of 0.7 mm to produce the insect-controlling resin molded article of Example 1.

[0033] In Example 1, only the number of gates (b) was changed to eight, and thus a pest-controlling resin molded article of Comparative Example 1 was produced. EXAMPLES

[0034] 7 parts by weight of ethylene-vinyl acetate copolymer (vinyl acetate content in copolymer: 20% by weight, product name: Ebatate H4011, manufactured by Sumitomo Chemical Co., Ltd.) and 2,3,5,6-tetrafluorobenzyl (1R,3S)-2,2-dimethyl-3-(2,2-dichlorovinyl)cyclopropanecarboxylate (Transfluthrin, product name: Biothrin) R12.5 parts by weight of polyethylene (Sumikathene FV405, manufactured by Sumitomo Chemical Co., Ltd.), 4.5 parts by weight of Carplex #80, and 76 parts by weight of polyethylene (Sumikathene FV405, manufactured by Sumitomo Chemical Co., Ltd.) were melt-kneaded using an internal pressure kneader (manufactured by Moriyama Seisakusho Co., Ltd.), and the kneaded product obtained was hot-cut while being extruded from an extruder to obtain a pellet-shaped resin composition. The melt flow rate of this resin composition was 18. Next, the shape of the pest control resin molded article was the same as that of Example 1, and the pellet-shaped resin composition was melted at 190°C in an injection molding machine, and then the resin was injected into the mold at a pressure of 200 MPa, the number of gates (b) was 5, and the gate diameter was 0.7 mm to produce a pest control resin molded article.

[0035] In Example 1, only the number of gates (b) was changed to four, and a pest-control resin molded article of Comparative Example 2 was produced. EXAMPLES

[0036] 50 parts by weight of ethylene-vinyl acetate copolymer (ratio of vinyl acetate in copolymer: 20% by weight, trade name: Ebatate H4011, manufactured by Sumitomo Chemical Co., Ltd.), 10 parts by weight of 2,3,5,6-tetrafluoro-4-methoxymethylbenzyl (1R)-trans-2,2-dimethyl-3-[(Z)-1-propenyl]cyclopropanecarboxylate (Metofluthrin, trade name: Eminence, manufactured by Sumitomo Chemical Co., Ltd.), 5 parts by weight of Carplex #80 (manufactured by EVONIK Co., Ltd.), and 35 parts by weight of polyethylene (Sumikathene FV405, manufactured by Sumitomo Chemical Co., Ltd.) were melt-kneaded using an internal pressure kneader (manufactured by Moriyama Seisakusho Co., Ltd.), and the kneaded product obtained was hot-cut while being extruded from the extruder to obtain a pellet-shaped resin composition. The melt flow rate of this resin composition was 28. Next, the pest control resin molding was designed to have an elliptical shape with a long diameter of 135 mm and a short diameter of 105 mm, with curved parts such that the outer frame 1 was 1 mm thick and 1 mm wide, the reinforcing member 2 was 1 mm thick and 1 mm wide, the square 3 was 1 mm thick and 1 mm wide, and the height 31 was 10 mm, and the total length (a) of the outer frame, reinforcing member and square 3 of the pest control resin molding was 802 cm. The pellet-shaped resin composition was melted at 190°C in an injection molding machine, and the resin injection pressure into the mold was set to 200 MPa, the number of gates (b) was 6, and the gate diameter was set to 0.7 mm to produce the pest control resin molded body of Example 3. EXAMPLES

[0037] 40 parts by weight of ethylene-vinyl acetate copolymer (ratio of vinyl acetate in copolymer: 25% by weight, trade name: Acryft RK307, manufactured by Sumitomo Chemical Co., Ltd.), 10 parts by weight of 2,3,5,6-tetrafluoro-4-methoxymethylbenzyl (1R)-trans-2,2-dimethyl-3-[(Z)-1-propenyl]cyclopropanecarboxylate (Metofluthrin, trade name: Eminence, manufactured by Sumitomo Chemical Co., Ltd.), and 50 parts by weight of polyethylene (Sumikathene FV405, manufactured by Sumitomo Chemical Co., Ltd.) were melt-kneaded using an internal pressure kneader (manufactured by Moriyama Seisakusho Co., Ltd.), and the kneaded product obtained was hot-cut while being extruded from the extruder to obtain a pellet-shaped resin composition. The melt flow rate of this resin composition was 7.9. Next, the pest control resin molding was designed to have an elliptical shape with a long diameter of 135 mm and a short diameter of 105 mm, with curved parts such that the outer frame 1 was 1 mm thick and 1 mm wide, the reinforcing member 2 was 1 mm thick and 1 mm wide, and the square 3 was 1 mm thick, 1 mm wide and 3 mm high, and the total length (a) of the outer frame, reinforcing member and square 3 of the pest control resin molding was 257 cm. The pellet-shaped resin composition was melted at 190°C in an injection molding machine, and the resin injection pressure into the mold was set to 200 MPa, the number of gates (b) was 3, and the gate diameter was set to 0.7 mm to produce the pest control resin molded body of Example 4.

[0038] Table 1 shows the production results. [Table 1] [Explanation of symbols]

[0039] 1 Outer frame 2 Reinforcement members 3. Timber 4 Openings

Claims

1. A method for manufacturing a pest control resin molded body by injection molding, the pest control resin molded body comprising an outer frame body, a plurality of reinforcing members arranged inside the outer frame body, and a plurality of rectangular timbers having at least a three-dimensional curved portion arranged inside the outer frame body, the method comprising the steps of: After filling a resin composition containing a volatile insect repellent and a resin into an injection molding machine, The resin composition is melted in a cylinder of an injection molding machine, and then the resin composition is injected into a cavity in a mold through a gate provided in the mold to obtain the pest control resin molded body (wherein the temperature in the cylinder is 160 to 220°C, the mold temperature is 150 to 200°C, and the injection pressure of the resin composition is 100 to 300 MPa). When the total length of the outer frame, the square bars, and the reinforcing members is a (cm), the number of gates provided in a mold used in the injection molding is b (pieces), and the logarithm of the melt flow rate (g / 10 min) of the resin composition measured at a load of 2.16 kgf and a test temperature of 190° C. based on JIS K7210 is c in common logarithm, (Formula) a / (b×c)≦100 and then injection-molding the resin composition into the mold, the resin composition satisfying the above condition (wherein the melt flow rate of the resin composition is 1 to 50 g / 10 min).

2. A method for manufacturing a resin molded body for pest control as described in Claim 1, wherein the thickness or width of the outer frame body, the reinforcing member and the square timber are each in the range of 0.1 to 3 mm.

3. A method for manufacturing a resin molded body for pest control as described in claim 1 or 2, wherein the total length of the outer frame body, the square timber, and the reinforcing members is 100 to 15,000 cm.

4. A method for producing a resin molded body for pest control described in any one of claims 1 to 3, wherein the resin contains one or more types selected from the group consisting of ethylene-methacrylic acid copolymers and ethylene-vinyl acetate copolymers.

5. A method for producing a resin molded body for pest control described in any one of claims 1 to 4, wherein the volatile insect repellent contains a pyrethroid compound.

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