JP2003064232A - Pvc-based resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a PVC-based resin composition capable of preventing electric characteristics from deterioration due to low susceptibility to temperature and moisture. SOLUTION: The PVC-based resin composition is obtained by blending a soft polyvinyl chloride compound with a foamed acrylonitrile-based polymer. The soft polyvinyl chloride compound is a molding material just prior to molding a soft polyvinyl chloride resin article prepared by blending a polyvinyl chloride resin with a stabilizer, a lubricant, a pigment, a filler and a plasticizer and kneading. The foamed acrylonitrile-based polymer is an acrylic resin foam. Such PVC-based resin composition is used as a sheath material 13 which covers collectively insulated wires 12, 12 in a flat cable 11.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PVC resin composition used for insulators, sheaths and the like of insulated wires and cables. [0002] In recent years, the number of insulated wires covered with a synthetic resin has increased. Although the purpose of using such a synthetic resin insulating material often serves also as a purpose as a structural material, the main focus is on electrically insulating the conductor from a conductor. However, even if the electrical insulation is excellent, the heat resistance is poor, the processing is difficult, the price is high, and the workability of the construction is poor. Will be gone. For this reason, as an insulating material, not only good electrical characteristics, but also good electrical characteristics, as well as heat resistance, ease of processing, cost, ease of construction, etc. Is an important criterion for selection. As a synthetic resin used for insulating such insulated wires and cables, a vinyl chloride resin is mainly used. Such a vinyl chloride resin is used for an insulator or a sheath of a power cable, an indoor electric wire, an electric wire for an automobile, or the like to be wired in a general building.
And the vinyl chloride resin composition which comprises an insulator and a sheath conventionally mixes a plasticizer, a stabilizer, and a filler with polyvinyl chloride. [0004] A vinyl insulated vinyl sheath cable such as an electric wire for an automobile using such a vinyl chloride resin composition has a structure as shown in FIG. That is, the vinyl insulated vinyl sheath cable 1 is
Are covered with vinyl chloride resin insulators 3 and 3, and the insulators 3 and 3 are covered with a vinyl chloride resin sheath 4. When such a polyvinyl chloride resin is coated on the conductors 2 and 2 or as the sheath 4, gelled polyvinyl chloride containing a plasticizer, a stabilizer, and a filler is mixed using an extruder. This is done by extruding. [0005] In recent years, with the increasing use and size of electric appliances, the amount of electric wires laid indoors has been steadily increasing. And the weight of the wires in the wiring room is beyond imagination. In automobiles, the number of electrical and electronic wiring circuits in automobiles has increased significantly due to the digitization of in-vehicle devices, etc. Have been. Therefore, in recent years, research has been conducted on reducing the weight of insulated electric wires for general indoor use and electric wires for automobiles. [0006] The use weight of the insulated wire can be reduced by reducing the conductor diameter of the insulated wire. However, when the conductor diameter is reduced, the mechanical strength is reduced, and the joint of the conductor is reduced. There is a problem that a part is detached or a disconnection occurs. Therefore, attempts have been made to reduce the weight of the insulator and sheath covered by the conductor of the insulated wire to reduce the total weight of the wire used in the automobile. In order to reduce the weight of the insulator and the sheath, it is conceivable to reduce the thickness of the insulator and the sheath. It has been found that it is difficult to realize such a short circuit between conductors and a problem in electrical insulation even in normal use. Therefore, in order to sufficiently secure the thickness of the insulator and the sheath and to reduce the weight of the insulator and the sheath, it is necessary to use a polyvinyl chloride foam for the vinyl chloride resin of the insulator and the sheath. Can be considered. Conventional polyvinyl chloride foams are obtained by adding phthalate plasticizer, Pb stabilizer, magnesium silicate (filler) to polyvinyl chloride.
It is constituted by blending ADCA (foaming agent). This foaming employs chemical foaming in which a foaming agent is added and foaming is performed using gas generated in a polycondensation process of the material. The above-mentioned conventional polyvinyl chloride-based foam has an electrical characteristic (volume specific resistance) which is lower than that of the vinyl insulated vinyl sheath cable 1 shown in FIG. It is inferior and cannot be used as an insulator or a sheath coated on the conductor of the insulated wire. (The electric characteristics (volume resistivity) decrease because the foaming agent (ADCA) When the hydroxyl group (OH
It is conceivable that a residue containing the group is generated). Further, in the above-mentioned conventional polyvinyl chloride foam, since it is a chemical foam, seasonal variations are unavoidable due to the influence of temperature and humidity. The present invention has been made in view of the above circumstances, and has as its object to provide a PVC resin composition which is hardly affected by temperature and humidity and can prevent a decrease in electric characteristics. [0012] The PVC resin composition of the present invention according to the first aspect of the present invention, which has been made to solve the above problems, is obtained by blending an acrylonitrile polymer foamed into a soft vinyl chloride compound. It is characterized by becoming. According to the first aspect of the present invention,
Soft vinyl chloride compound is a molding material immediately before compounding a stabilizer, a lubricant, a pigment, a filler, and a plasticizer into a vinyl chloride resin, kneading and molding into a soft vinyl chloride resin product, and a foamed acrylonitrile-based material. The coalescence is an acrylo resin foam. The acryl resin foam is a foam formed by decomposing a foaming agent in the production process and simultaneously crosslinking a polymer. A PVC resin composition obtained by blending a foamed acrylonitrile polymer with a soft vinyl chloride compound has a low specific gravity and can provide the same effect as a conventional polyvinyl chloride foam. Further, since the foamed acrylonitrile-based polymer has good compatibility, a decrease in stress and elongation can be suppressed. Furthermore, since no by-products are generated, a decrease in electrical characteristics is suppressed. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of an insulated wire / cable to which the PVC resin composition of the present invention is applied. In addition, the PVC resin composition of the present invention comprises:
The present invention can be applied to general indoor insulated wires and cables, automotive wires and cables, and the like. In the present embodiment, a flat cable will be described as an example. In FIG. 1, a flat cable 11 has insulated wires 12, 12 arranged in parallel on the same plane, and a sheath 13, which is collectively covered on the insulated wires 12, 12. It is configured. The insulated wires 12, 1
2 has conductors 14 and 14 of a known configuration, and insulators 15 and 15 coated thereon. Also,
The sheath 13 (which may include the insulators 15 and 15) is formed of the PVC resin composition of the present invention. The PVC resin composition will be specifically described in the following examples. The resin composition is obtained by mixing a foamed acrylonitrile-based polymer with PVC as a sheath material. By mixing the foamed acrylonitrile-based polymer with PVC, a foamed PVC-based resin composition is obtained. Such a PVC-based resin composition of the present invention has advantages such as low specific gravity, good compatibility, and no generation of by-products (no generation of residues). EXAMPLES Specific examples of the PVC resin composition will be described. Here, Example 1, Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3 will be described as examples. Example 1 In Example 1, as shown in Table 1, 10 parts by weight of a foamed acrylonitrile-based polymer (Dieform: manufactured by Dainichi Seika Co., Ltd.) was added to 100 parts by weight of a soft vinyl chloride compound. Parts. The specific gravity of the soft vinyl chloride compound (described as "soft PVC" in Table 1) is 1.36, and the specific gravity of the acrylonitrile-based polymer is 0.11. Example 2 In Example 2, as shown in Table 1, 20 parts by weight of a foamed acrylonitrile-based polymer (Dieform: manufactured by Dainichi Seika Co., Ltd.) was added to 100 parts by weight of a soft vinyl chloride compound. Parts. The specific gravity of the soft vinyl chloride compound (described as "soft PVC" in Table 1) is 1.36, and the specific gravity of the acrylonitrile-based polymer is 0.11. Comparative Example 1 In Comparative Example 1, as shown in Table 1, 30 parts by weight of a foamed acrylonitrile-based polymer (Dieform: manufactured by Dainichi Seika Co., Ltd.) was added to 100 parts by weight of a soft vinyl chloride compound. Parts. The specific gravity of the soft vinyl chloride compound (described as "soft PVC" in Table 1) is 1.36, and the specific gravity of the acrylonitrile-based polymer is 0.11. Comparative Example 2 In Comparative Example 2, as shown in Table 1, 40 parts by weight of an acrylonitrile-based polymer (die form: manufactured by Dainichi Seika Co., Ltd.) was foamed with respect to 100 parts by weight of a soft vinyl chloride compound. Parts. The specific gravity of the soft vinyl chloride compound (described as "soft PVC" in Table 1) is 1.36, and the specific gravity of the acrylonitrile-based polymer is 0.11. Comparative Example 3 In Comparative Example 3, as shown in Table 1, 0.04 parts by weight of ADCA (foaming agent) was added to 100 parts by weight of a soft vinyl chloride compound. Here, in measuring the volume resistivity in Table 1, the following process is performed. That is, the sample 16 is extruded from the extruder to form a 150 mm × 150 mm square sample 1 mm thick sheet 16 as shown in FIGS. The main electrode 17 is formed by attaching an aluminum foil to the front surface of the sample 16, and the counter electrode 18 is similarly formed by attaching an aluminum foil to the back surface. Reference numeral 19 denotes a guard electrode, which is formed in a ring shape around the main electrode 17 so as not to contact the main electrode 17. Thus, the three electrodes 17, 18, 19
Between the main electrode 17 and the counter electrode 18 of the sample 16 on which
After applying a voltage of 0 V for one minute, a current flowing through the sample 16 between the main electrode 17 and the guard electrode 19 was measured.
Is measured by the ammeter 20. This volume specific resistance value ρV is given by ρV = (πd ² / 4t) × Rv
(ΡV: volume resistivity [Ω · cm], R
v: volume resistance [Ω], t: sample thickness [cm], d: main electrode diameter [cm]). The sheath deformation, stress (tensile strength) and elongation in Table 1 are based on Japanese Industrial Standard JIS C 3005.
Shall conform to the test of In the evaluation of the sheath deformation, a foaming rate of 0% or more is good (denoted by “○”), and the deformation is slightly better than that of 0% (denoted by “△”), and the deformation is easily poor. (Described as “x”). In the tensile strength test, the material (Examples 1 and 2,
A sheet having a thickness of 1 to 2 mm was extruded by extruding a sheet (based on each composition of Comparative Examples 1 to 3) and allowed to stand at room temperature for 24 hours or more. , Predetermined tensile speed (200mm / min)
And the maximum tensile load (tensile strength) of the test piece and the length (elongation) between the marked lines at the time of cutting are simultaneously measured. The target value of the tensile strength is 10 MPa or more (if it is less than 10 MPa, there is a concern about brittleness).
The target value of the tensile elongation is 200% or more (because sufficient flexibility cannot be obtained if the elongation is less than 200%). [Table 1] From the results shown in Table 1, the foaming ratio (%) was “10%” in Example 1, “20%” in Example 2, “32%” in Comparative Example 1, and “39%” in Comparative Example 2. And Comparative Example 3 is "20
% ", The specific gravity of Example 1 was" 1.24 ", Example 2 was" 1.11 ", Comparative Example 1 was" 1.22 ", Comparative Example 2
Was "0.863" and Comparative Example 3 was "1.09".
Example 1 and Example 2 have the effect that the specific gravity is light, the thickness of the sheath is sufficiently secured, and the weight can be reduced, as in Comparative Example 3 of the chemical foaming. Further, since the foamed acrylonitrile-based polymer has a higher ratio in the soft vinyl chloride compound than ADCA, it also has an effect of being uniformly dispersed and obtaining a stable foamed state. From the results in Table 1, the volume resistivity (Ω · cm) of Example 1 was “1.58 × 10 ¹² Ω · cm”.
cm), Example 2 is “0.95 × 10 ¹² Ω · cm”,
Comparative Example 3 was “0.112 × 10 ¹² Ω · cm” (Comparative Examples 1 and 2 were omitted). In Examples 1 and 2, even if a foamed acrylonitrile-based polymer was blended, there was no generation of by-products as in the case of using a chemical foaming agent (ADCA) or the like. Resistance) can be suppressed. From the results in Table 1, the sheath deformation is
Example 1 was “○”, Example 2 was “○”, Comparative Example 1 was “△”, Comparative Example 2 was “×”, and Comparative Example 3 was “○”. Example 1 and Example 2 have an effect that the foaming ratio is equal to 0% together with Comparative Example 3 of chemical foaming. From the results of Comparative Example 1 and Comparative Example 2, it was found that when the blended amount of the foamed acrylonitrile-based polymer was 30 parts by weight or more, there was difficulty in sheath deformation. From the results shown in Table 1, the stress (MPa)
In Example 1, "12.5 MPa" was used, and in Example 2, "12.5 MPa" was used.
1.0 MPa ", Comparative Example 1 was" 10.0 MPa ", Comparative Example 2 was" 9.4 MPa ", and Comparative Example 3 was" 10.5 MPa ".
a ”, and the elongation (%) was“ 350% ”in Example 1,
Example 2 was "320%", Comparative Example 1 was "280%", Comparative Example 2 was "250%", and Comparative Example 3 was "315%". Example 1 and Example 2 have an effect that sufficient stress (MPa) and elongation (%) can be obtained as compared with Comparative Example 3 of chemical foaming. Further, since the foamed acrylonitrile-based polymer has good compatibility, it also has an effect of suppressing a decrease in stress (MPa) and elongation (%). On the other hand, apart from the results shown in Table 1, Examples 1 and 2 have an effect that there is no seasonal variation because no chemical blowing agent (ADCA) is used. In addition, it goes without saying that the present invention can be variously modified without departing from the spirit of the present invention. That is, in the above description, the PVC resin composition of the present invention is applied to the sheath 13 and used. However, the present invention is not limited to this, and the sheath can be used for the insulator 15 of the insulated wire 12. As described above, according to the present invention,
The effect of being able to provide a PVC-based resin composition that is less susceptible to temperature and humidity and that can prevent a decrease in electrical properties can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an embodiment of an insulated wire / cable to which a PVC resin composition according to the present invention is applied. FIG. 2 is an explanatory view in a perspective direction regarding a method of measuring a volume specific resistance value. FIG. 3 is an explanatory diagram in a front view direction regarding a method of measuring a volume specific resistance value. FIG. 4 is a perspective view of a conventional vinyl insulated vinyl sheath cable. [Description of Signs] 11 Flat cable 12 Insulated wire 13 Sheath 14 Conductor 15 Insulator

Claims (1)

Claims: 1. A PVC resin composition comprising a foamed acrylonitrile polymer mixed with a soft vinyl chloride compound.