JPS61262114A - Preparation of rodent resistant molding - Google Patents

Abstract

PURPOSE:To obtain a rodent-resistant molding having extremely high residue of cycloheximide, by supplying the mixture of powders of a polymer of vinyl chloride type and a cycloheximide to the feed zone of extruder, and molding by extrusion. CONSTITUTION:Raw material are fundamentally the powders of polymer of vinyl chloride type and cycloheximide, and if necessary, may be also mixed with agents which are usually compounded in the polymer of vinyl chloride type, for example esteric plasticizers, inorganic fillers, stabilizers or lubricants, pigments, etc. The usage of cycloheximide is 0.1-10 parts, preferablly 0.5-5 parts by weight to 100 parts by weight of the polymer of vinyl chloride type. The used raw materials are practically uniformly mixed into the state of powder mixing, and this mixture is supplied to the feed zone of the extruder. While these condition are satisfied, it is possible to mix in various methods and supply to the extruder.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a novel method for manufacturing windproof molded articles, such as ratproof cables.

[Prior art]

BACKGROUND ART Conventionally, in order to protect plastic structures installed on the ground or underground, such as cables and pipes, from wind damage, it has been widely adopted to coat the plastics with a windproofing agent, cycloheximide.

However, since paints containing cycloheximide have problems such as toxicity and flammability, it has recently been proposed to mix cycloheximide directly into plastics (for example, Japanese Utility Model Application No. 57-76315).

[Problem that the invention seeks to solve]

By the way, experiments conducted by the present inventors have revealed that cycloheximide has a problem in that it rapidly decomposes when heated in the coexistence of a vinyl chloride-based trimer such as polyvinyl chloride. For this purpose, when a vinyl chloride polymer and cycloheximide are mixed under heating using a Banbury mixer or the like, pelletized, and the pellets are fed to an extruder for extrusion molding according to the conventional method, during these series of processing steps, Most of the cycloheximide decomposes, leaving only a portion of the amount used remaining in the molded product. Some proposals have been made to incorporate a large amount of cycloheximide in advance in anticipation of the amount of decomposition during the processing process, but as it is well known that dicycloheximide is an extremely expensive chemical, such a large amount of compounding may increase the cost of the molded product. Become.

[Means for solving problems]

In order to solve the above-mentioned problems, the present inventors conducted extensive research and confirmed the following fact. That is, when a mixture of vinyl chloride polymer powder and cycloheximide powder is fed to an extruder and extruded under the usual extrusion conditions for the polymer, compared to the conventional method that involves kneading and pelletizing steps, , the residual amount of cycloheximide in the extruded product is extremely high; and (b) even if a mixture of the above powders is mixed to some extent and extrusion molded by direct extrusion, the degree of dispersion of cycloheximide in the extruded product is low. The two points are that it has sufficient uniformity when purchased and there is no problem in terms of wind protection.

The present invention has been completed based on the novel findings of (P) and (H) above. That is, the present invention involves mixing vinyl chloride polymer powder and cycloheximide powder, and extruding the resulting powder mixture. It is an object of the present invention to provide a method for producing a rodent-proof molded article, which is characterized in that the product is supplied to a feed zone of a machine and extrusion molded by the extruder.

[For production]

Unlike the conventional method described above, a mixture of powders of vinyl chloride polymer and cycloheximide is extruded without going through the vatting process. It only needs to be heated, so its decomposition is unexpectedly mild. Furthermore, from the viewpoint of rodent resistance, cycloheximide is substantially and sufficiently dispersed in the extruded product.

[Detailed description of the invention]

Examples of vinyl chloride polymers to be used in the present invention include polyvinyl chloride, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate-vinyl chloride graft copolymer, and ethylene-ethyl acrylate-vinyl chloride graft copolymer. Polymer, ethylene-propylene-vinyl chloride ST kraft copolymer, ethylene-butene-1-vinyl chloride graft copolymer, chlorinated polyethylene, chlorinated polyethylene-vinyl chloride graft copolymer, chlorosulfonated polyethylene, chlorosulfone Polyethylene chloride-vinyl chloride graft copolymer, etc.

The raw materials used in the present invention are basically vinyl chloride polymer powder and cycloheximide powder, but if necessary, agents that are usually blended with vinyl chloride polymers,
For example, esters of organic acids such as phthalic acid, adipic acid, trimellitic acid, and azefiic acid, ester plasticizers such as polyester, inorganic fillers such as talc, clay, and calcium carbonate, tribasic lead sulfate, and dibasic Stabilizers such as lead sulfate, lubricants, pigments, etc. may be mixed.

The amount of cycloheximide used is vinyl chloride polymer 1
0.1-101 per 00 parts by weight! It is a quantity part.

If the amount is less than 0.1 part by weight, the rodent repellent effect will be poor.On the other hand, in the present invention, the remarkable effect of the present invention is due to the fact that a high percentage of cycloheximide remains and the rodent repellent effect of cycloheximide is saturated. Therefore, using more than 10 parts by weight of cycloheximide is wasteful and causes an increase in cost. The preferred amount of cycloheximide used is 0.5 to 5 parts.

When using plasticizers and inorganic fillers, the use of excessive amounts of these agents will reduce the physical properties of the resulting composition, so the amount of these agents used should be less than 100% of the vinyl chloride polymer.
It is preferable that the amount of each is less than 100 parts by weight, particularly less than 80 parts by weight, per heavy weight part.

In the present invention, the raw materials used are mixed almost uniformly (mixed to form a powder mixture state, and this mixture is supplied to the feed zone of the extruder. As long as this condition is satisfied, the raw materials used are mixed in various ways and extruded. For example, a method of mixing using a low-speed mixer such as a Tump-Two or a high-speed mixer such as a Henschel mixer and feeding the resulting powdery mixture to an extruder; A method may also be used in which the drug is mixed at low or high speed while being fed into the feed zone of the extruder.Which mixing method is adopted, mixing should be carried out at a low temperature of 120°C or lower, especially 100°C or lower. preferable.

In the present invention, raw materials containing the three components consisting of vinyl chloride polymer powder, cycloheximide powder, and plasticizer, as well as other chemicals added as necessary, are heated to 50℃ and 10℃.
It is particularly preferable to mix using a high-speed mixer such as a Henschel mixer in a temperature range of 0° C. or lower. According to this method, a mixture can be obtained in which the additive agent described above is uniformly and firmly captured in the vinyl chloride polymer powder. The mixture in this state is difficult to separate cycloheximide, so it is easy to handle after mixing, and it is also easy to extrude. There is an advantage that an extrusion molded product with a better dispersion state of dicycloheximide can be obtained.

Apply the above powder mixture on the sheath of the insulated wire KO01~
A rodent-proof wire extruded to a thickness of 2fi is a preferred embodiment of the present invention.

〔Example〕

Examples 1 to 3, Comparative Example 1 The table below summarizes the composition, mixing, and extrusion processing conditions of the compositions used in each Example and Comparative Example.

In Examples 1 to 3, powder mixtures obtained by mixing using a Henschel mixer were supplied to an extruder and extruded. In Comparative Example 1, a mixture obtained by Dohuy blending using a conventional method was fed to a mixtruder whose temperature was adjusted to 130°C to 140°C, followed by cross-wire extrusion, then pelletizing, and the resulting pellet was fed in an extrusion manner. Extruded.

The amount of residual cycloheximide was determined using the sample taken from the wire coating obtained by extrusion molding according to "Yakugaku Kenkyu" Vol. 33, 4.
The apparatus was set up using the spectroscopic method described on page 54 (1961) K. The residual rate was calculated from the detected residual amount and the amount administered for formulation.

The following margins (Note 1) Powder of ethylene-vinyl chloride copolymer (ethylene content j17.5X electric%, average degree of polymerization 1050) (Note 2) Powder of polyvinyl chloride (average degree of polymerization 00) (Note 8) Ethylene・Vinyl acetate-vinyl chloride graft copolymer (ethylene, vinyl acetate containing mso superposition %)
It will be understood from the table above that a large residual rate of cycloheximide was achieved by the method of the present invention, compared to the residual rate of cycloheximide in the comparative example.

Further, the dispersion state of cycloheximide in each example was extremely good.

[Effects of the Invention] According to the present invention, cycloheximide, which is an extremely expensive drug, can be left in a product at a high residual rate, and the drug can actually be blended with good dispersibility.

Claims (1)

[Claims] 1. The method is characterized by mixing vinyl chloride polymer powder and cycloheximide powder, supplying the resulting powder mixture to the feed zone of an extruder, and extrusion molding the extruder. A method for manufacturing a rodent-proof molded product. 2. The manufacturing method according to claim 1, wherein the vinyl chloride polymer powder and the cycloheximide powder are uniformly mixed by high-speed mixing at a temperature of 100° C. or lower.