JPH0322418B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a thermoplastic resin composition containing polyvinyl chloride resin as a main ingredient and having excellent rodent repellency, and the purpose of this invention is to obtain a thermoplastic resin composition which is highly effective in repelling rodents. In addition, heat resistance, water resistance, UV resistance,
Since the safety is dramatically improved compared to conventionally known rodent-proofing resin compositions, it is possible to stabilize the rodent-proofing effect and moldability of the product itself that is actually molded using this composition. The aim is to improve economic efficiency. The composition can be used in various forms such as films, sheets, tapes, tubes, wire coatings, injection molded products, etc., but it is especially useful for indoor and outdoor wiring where there is a risk of electric leakage fires caused by rodent damage. It is highly effective as a material for insulation, sheaths, protective tubes, tapes, etc. for vinyl insulated wires for use in commercial use, computers and signal cables where there is concern about serious social damage due to communication interruptions or malfunctions. [Prior Art] Conventionally, various drugs have been used to protect electric wires, cables, etc. from rat attacks, as mentioned above, but among them, cycloheximide (hereinafter referred to as CHI) crystals have been widely used due to its efficacy and safety. ,
We have a long track record. However, it is known that when CHI crystals are heated to high temperatures, they are thermally decomposed and the residual rate of the drug is reduced, and especially in the coexistence of polyvinyl chloride, the thermal stability is significantly reduced. Therefore, when adding CHI crystals to resin and mixing and kneading, it is common practice to add an extra amount of CHI crystals in advance and mix and knead them in anticipation of a decrease in the residual rate. Using large quantities was a major economic hindrance. Furthermore, CHI crystal itself has poor water resistance, chemical resistance, and ultraviolet resistance, leaving concerns about the stability of the rat-proofing effect when molded products to which it is added are used for long periods of time. Furthermore, when CHI crystals are added and kneaded at high temperatures such as when molding ordinary resins, or when CHI crystals are kneaded into resin in advance (hereinafter, this pellet-like material is referred to as a compound), ) is further heated and melted and molded, it emits a pungent odor that humans dislike, which hinders work.
Additionally, there were problems in terms of environment and safety, such as dust and exhaust gas. [Object of the Invention] The present invention aims to improve the heat resistance, water resistance, ultraviolet resistance, safety, etc., while taking advantage of the high rat repellent effect of the conventional rat-proof thermoplastic resin composition containing CHI crystals. As a result of research aimed at improving
By skillfully combining kneading methods and the like, we have found a rodent-proof thermoplastic resin composition that has improved the above-mentioned drawbacks, has good moldability, and is extremely economically viable. [Structure of the Invention] The present invention consists of: a. 100 parts by weight of polyvinyl chloride resin; b.
Contains cycloheximide with a content of 1 to 40% by weight, and has a primary particle size of 0.1 to 10 μm and a secondary particle size of 1 to 10 μm.
80μ microencapsulated formulation 0.5-10 parts by weight, c.
A rodent-proof thermoplastic resin composition containing 20 to 200 parts by weight of a plasticizer, an electric wire or cable coated with the composition, and a protective tube made of the composition;
Film, sheet or tape. As the rodent repellent used in the present invention, cycloheximide microencapsulated using melamine resin (trade name: Naramycin Microcapsules, manufactured by Tanabe Pharmaceutical Co., Ltd.) is used, and the particle size of the primary particle is 0.1. ~10μ, with a secondary particle diameter in the range of 1~80μ. The reason for this is that most of the electric wires, cables, tubes, etc. that are used are extrusion-molded products, and the surface appearance of these products is a problem in terms of their product value.As a result of extensive research, the inventor of the present invention found that It has been found that the particle size of the CHI microencapsulated preparation to be added, especially its secondary particle size (hereinafter referred to as particle size), has a significant effect on its surface appearance, especially its smoothness and local unevenness. Specifically, it is desirable that the primary particle size is in the range of 0.1 to 10 μm and the secondary particle size is in the range of 1 to 80 μm.If the particle size is larger than that, the entire surface of the product may become rough, or parts of the product may become rough. If the particle size is smaller than this range, there will be a lot of dust during addition and kneading, which will have a negative impact on the working environment. In addition, conventional soft polyvinyl chloride resin containing CHI crystals does not have the necessary rodent-repellent properties.
It is known that the effective amount of CHI is around 0.1% by weight or more, and it is known that the effective amount of CHI is around 0.1% by weight or more.
Since the CHI content is usually 8% by weight, the amount added to the microencapsulated preparation is approximately 1.25%.
The present invention shows that by skillfully combining the kneading temperature and kneading method during the production of the composition, the CHI residual rate can be increased, that is, the amount of expensive microencapsulated preparations added can be reduced, and economic efficiency can be improved. Well, I found it. Specifically, the CHI residual rate can be reduced by lowering the kneading temperature when adding microencapsulated preparations to a temperature that is as low as the melting temperature of the resin, and by delaying the addition time, that is, by shortening the thermal history of microencapsulated preparations as much as possible. It is possible to raise it. Furthermore, the present inventors have found that economical efficiency can be further improved by forming the wire covering portion or tube into a two-layer structure and thinly coating the high concentration portion of the microencapsulated preparation on the outer layer. In other words, in the scope of the claims of the present invention, the amount of b added is determined by the balance between rodent resistance and economical efficiency, as described in the examples, and by combining these with other compounding agents, it is possible to achieve In the present invention, we have discovered an excellent rodent-proof thermoplastic resin composition that has advantages that cannot be overcome. In addition, the polyvinyl chloride resin in the present invention refers to not only vinyl chloride homopolymer but also replacing all or part of it with a copolymer resin mainly composed of vinyl chloride resin to the extent that the properties of the vinyl chloride resin are not impaired. You can also do it. Examples of such copolymer resins include ethylene/vinyl chloride copolymers, vinyl acetate/vinyl chloride copolymers, and others. In addition, the plasticizers may be those commonly used, such as phthalate ester plasticizers, fatty acid ester plasticizers such as adipate esters, trimellitic acid ester plasticizers, phosphate ester plasticizers,
Examples include chlorine-containing plasticizers such as chlorinated paraffin, plasticizers made of epoxy derivatives, polyester plasticizers made of polymers of dibasic acids and dihydric alcohols, and others. The amount of plasticizer can be varied in the range of 20 to 200 parts by weight depending on the flexibility and other requirements of the product, and the range of 30 to 150 parts by weight is widely used for flexible polyvinyl chloride resin. be. The composition of the present invention does not prevent the addition of other compounding agents, such as heat stabilizers, colorants, lubricants, anti-aging agents, fillers, flame retardants, etc. that are added to ordinary vinyl chloride resins. can be added. [Example] Examples will be described below. [Example 1] The blended composition shown in Table 1 was kneaded for about 5 minutes in a 16-inch diameter heated roll mill, and the mixture was kneaded to a thickness of 2 to
The 3 m/m sheet is further cut into 2 to 5 m/m square pellets using a pelletizer (hereinafter, this pellet form is referred to as PVC compound). '', the kneading temperature is the surface temperature of the heating roll, and the ``normal'' and ``post-feeding'' kneading methods refer to the method of blending all the compounded compositions in advance and feeding them into the rolls at once. ”, and among combination drugs
"Post-injection" is a method in which ingredients other than the microencapsulated formulation containing CHI are blended in advance, rolled, kneaded, and gelled, and then only the microencapsulated formulation containing CHI is added afterwards. Furthermore, the "theoretical value of CHI content" is the weight percent of the active ingredient CHI calculated from the formulation shown in Table 1, and the "CHI residual rate" is the theoretical value of the actual measured CHI content in the PVC compound. It is a percentage divided by the value, and based on past experience, approximately 80% or more is preferable. Also, using the above PVC compound, 50m/mφ
The wire was extruded and coated using an extruder, and the resulting wire was subjected to a feeding damage test with actual rats. The wire structure is a single-core bare copper wire with a diameter of 1.6 mm, and the PVC compound is melt-coated to a thickness of 0.8 mm.
During extrusion, the temperature of the extruder die and crosshead was maintained at approximately 170°C, and the resin temperature was maintained at approximately 175°C, so that the wires were produced under the same temperature conditions as possible. "Odor during kneading and wire processing" in Table 1 represents the difference in the level of the pungent odor characteristic of CHI around the workplace during kneading in a roll mill and during wire extrusion coating. Explanation of symbols: ○...Low irritating odor ×...Strong irritating odor Also, the "surface appearance of the electric wire" refers to the smoothness of the surface of the prepared electric wire and the presence or absence of irregularities. Explanation of symbols: ○...Smooth and clean △...Slightly rough ×...Rough and partially uneven For the "rat-proofing effect of electric wires", we used a prepared electric wire cut into approximately 20 cm as a sample. Evaluation was conducted through a feeding damage test using actual rats. The details of the test method are as follows (1) Test mouse: Male or female Wistar rat, weight 350-450 g (2) Test procedure: A control wire (CHI (Electric wire of the same structure using the PVC compound of Comparative Example 10 that does not contain eyelashes) was installed to each one, fed and watered, and
After leaving it overnight (17 hours), visually observe the results of extraction. The cages used were 8 female cages and 6 male cages. (3) Explanation of symbols: ○...Extent of scratches on the surface (almost in its original shape) △...Deep scratches ×...Corrosion damage to the extent that exposed core wires are visible "Weather resistance of electric wires"'', a sample cut into approximately 20cm pieces was placed directly in a sunshine weather meter, and surface discoloration was observed after exposing it to a sunshine carbon arc lamp at 83°C for 600 hours. Explanation of symbols: ○...No change △...Slightly yellowish ×...Significant yellowish discoloration As shown in the examples and comparative examples in Table 1, CHI
By skillfully combining the particle size, kneading temperature, kneading method, etc. of the microencapsulated preparation containing CHI, we can increase the residual rate of CHI, which is effective for rat-proofing, and create excellent rodent-proof wires or tubes with a good surface appearance. This is a new discovery that it can be manufactured.

【table】

[Example 2]

The present inventors created a two-layered structure for the coated part or tubes of the electric wire using the novel resin composition described in the claims, and thinly coated the high concentration part of the microencapsulated preparation containing CHI. We have discovered that it is possible to produce products that are more economical and highly effective against rats. Examples are shown below. An electric wire was made using a PVC compound kneaded in the same manner as in Example 1. As shown in Figure 1, the wire has a two-layer structure, with a copper wire (outer diameter 1.6 mm) coated with an inner layer and an outer layer, and a total thickness of 0.8 mm for the inner and outer layers.
Among the formulations shown in Table 2, those containing microencapsulated preparations in the outer layer and not in the inner layer are used. The "rat-proofing effect" in Table 2 was evaluated by conducting the same feeding damage test by rats as in Example 1. "Comprehensive economic efficiency" here means that expensive rodent repellents are used only on the surface, albeit at a high concentration, to reduce the total cost of the coating while maintaining rodent repellency, and the final product is It takes into account the economic efficiency of the product, and the relative evaluations were given as A: "best," B: "average," and C: "poor." However, the method of coating the outer layer of the rodent-resistant surface in such a thin manner is
This tends to cause poor appearance such as surface roughness, but this can only be achieved by using the composition according to the present invention.

【table】 [Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an electric wire coated with two layers.

Claims (1)

[Scope of Claims] 1 a. Polyvinyl chloride resin 100 parts by weight b. Microencapsulated preparation containing cycloheximide containing 1 to 40% by weight and having a primary particle size of 0.1 to 10 μm and a secondary particle size of 1 to 80 μm
A rodent-proof thermoplastic resin composition containing 0.5 to 10 parts by weight c and 20 to 200 parts by weight of a plasticizer. 2. An electric wire or cable coated with the composition according to claim 1. 3. A protective tube, film, sheet or tape made from the composition according to claim 1.