JP2991401B2 - PVC foam insulating resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PVC resin composition used for an insulator, a sheath or the like of an electric cable.
In particular, it relates to a PVC-based foamed insulating resin composition for a foamed insulated cable using the foamed polyethylene resin composition for an insulator, a sheath, and the like.

[0002]

2. Description of the Related Art In recent years, the number of insulated wires covered with a synthetic resin has increased. In many cases, the purpose of use of such an insulating material is also to serve as a structural material, but the main purpose is to electrically insulate it from a conductor. However, even if the electrical insulation is excellent, the heat resistance is poor,
It is difficult to process, the price increases,
If the workability of the construction deteriorates, it cannot be used as an insulating material. For this reason, as an insulating material, not only the electrical characteristics are good, but also in addition to the electrical characteristics, heat resistance, ease of processing, price, ease of construction, etc. Is an important criterion for selection. As a synthetic resin used for insulating such electric 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 is conventionally comprised by mixing a plasticizer, a stabilizer, and a filler with polyvinyl chloride. Such a vinyl insulated vinyl sheath cable such as an automobile electric wire using a vinyl chloride resin has a configuration as shown in FIG. That is, the vinyl insulated vinyl sheath cable 1 covers the conductor 2 with the insulator 3 of vinyl chloride resin, and the insulator 3
Is covered with a sheath 4 of a vinyl chloride resin. Then, such a vinyl chloride resin is used as the conductor 2
In the case of coating as a sheath 4 or as a sheath 4, polyvinyl chloride gelled by blending a plasticizer, a stabilizer and a filler is extruded using an extruder.

[0003] In recent years, with the increasing use and size of electric appliances, the amount of electric wires to be wired indoors has been increasing, and the weight of electric wires in the wiring room has exceeded the imagination. Also, with the spread of AT (auto transmission) vehicles, control devices for automobiles have been changed from carburetors to electronic fuel injection devices, and on-board devices such as various instruments have been digitized. With the digitization of such in-vehicle devices, the number of electric and electronic wiring circuits in automobiles has significantly increased, the space occupied in automobiles has increased, and the total weight of automobiles due to electric wires for automobiles has increased. . Such an increase in the weight of the insulated wires has resulted in a robust construction of the building and a reduction in the fuel efficiency of the automobile.
It is desirable to be lightweight from the viewpoint of the structure of the building or from the viewpoint of improving fuel efficiency, and an increase in the amount of insulated wires used goes against the point of reducing the weight of the insulated wires. However, with the increasing use of electric appliances and their larger size, or in order to run automobiles safely and comfortably with a microcomputer, the use of general indoor insulated wires and the use of automobile wires have been increasing. The increase cannot be avoided. Therefore, in recent years, research has been conducted on weight reduction of insulated wires for general indoor use and wires for automobiles.

[0004] To reduce the weight used of the insulated wire,
This can be realized by reducing the conductor diameter of the insulated wire, but when the conductor outer diameter is reduced, the mechanical strength is reduced, and there is a problem that a joint portion of the conductor 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.
It is possible to reduce the weight of the insulator and sheath by reducing the thickness of the insulator and sheath.
If the thickness of the sheath is reduced, the conductors are short-circuited due to an abnormally high temperature in the engine room, and a problem occurs in electrical insulation even in normal use, which is difficult to realize. In order to sufficiently secure the thickness of the insulator and the sheath and reduce the weight of the insulator and the sheath, it is conceivable to use a polyvinyl chloride foam for the vinyl chloride resin of the insulator and the sheath. A conventional polyvinyl chloride foam is formed by blending polyvinyl chloride with a phthalate plasticizer, a Pb stabilizer, magnesium silicate (filler), and ADCA (foaming agent). This foaming is based on physical foaming, which applies physical changes such as decompression of compressed gas and vaporization of evaporative gas, or by using a gas generated in the process of polycondensation of a material by adding a foaming agent. Either method of chemical foaming for foaming is employed.

[0005]

The conventional polyvinyl chloride foam has an electrical characteristic (volume specific resistance) which is lower than that of the vinyl insulated vinyl sheath cable 1 shown in FIG.
However, it is not suitable for use as an insulator or a sheath coated on a conductor of an insulated wire.

[0006] The electrical characteristics (volume resistivity) of the conventional polyvinyl chloride foam are reduced by the blowing agent (ADC).
It is considered that a residue containing a hydroxyl group (OH group) is generated when A) foams. For this reason, the conventional polyvinyl chloride foam cannot be used as an insulator or sheath for covering the conductor of the insulated wire, and the thickness of the insulator and the sheath is sufficiently secured, and the weight of the insulator and the sheath is reduced. The problem is that it is not possible to alleviate the problem.

An object of the present invention is to provide a foamed state similar to the foamed state of the conventional polyvinyl chloride foam by using a smaller amount of the foaming agent than the conventional polyvinyl chloride foam. As a result, the foaming rate of the foaming agent is improved as compared with the conventional one, and the insulating material and the sheath thickness are kept the same as the conventional one by using a smaller amount of the insulating material and the sheath material. In order to prevent the deterioration of the electric characteristics.

[0008]

According to the first aspect of the present invention,
A vinyl chloride resin composition to which a plasticizer, a stabilizer, and a foaming agent have been added is one or more of anhydrous calcium silicate, anhydrous magnesium silicate, and anhydrous aluminum silicate, all of which are stearic acid and palmitic acid. Oleic acid or a filler that has been surface-treated with oleic acid. According to the second aspect of the present invention, 30 parts by weight of a phthalate plasticizer is added to 100 parts by weight of polyvinyl chloride.
To 100 parts by weight, 1 to 5 parts by weight of a Sn-based stabilizer, a Pb-based stabilizer or a Ca-Zn-based stabilizer, and 0.1 to 5 parts by weight of ADCA.
1 to 5 parts by weight of calcium silicate surface-treated with stearic acid, palmitic acid or oleic acid, or magnesium silicate surface-treated with stearic acid, palmitic acid or oleic acid, or stearic acid , An aluminum silicate surface-treated with either palmitic acid or oleic acid, and 30 to 70 parts by weight of a filler.

[0009]

According to the first aspect of the present invention, a surface treatment of a polyvinyl chloride resin composition obtained by adding a plasticizer, a stabilizer and a foaming agent to polyvinyl chloride is carried out with stearic acid, palmitic acid or oleic acid. Any one of magnesium silicate surface-treated with any of calcium silicate, stearic acid, palmitic acid, and oleic acid, and / or aluminum silicate surface-treated with any of stearic acid, palmitic acid, and oleic acid Since two or more fillers are blended and configured, the foaming of the conventional polyvinyl chloride foam can be performed with a blending amount smaller than the blending amount of the foaming agent blended in the conventional polyvinyl chloride foam. Rate can be obtained, and the foaming agent decomposition product residue can be reduced to prevent a decrease in electric characteristics. According to the invention as set forth in claim 2, 30 to 100 parts by weight of a phthalate ester-based plasticizer and 1 to 5 parts by weight of a Sn-based stabilizer, a Pb-based stabilizer or a Ca-Zn-based stabilizer are added to 100 parts by weight of polyvinyl chloride. Parts by weight, ADCA to 0.1 to 5 parts by weight, stearic acid,
Surface treated with either calcium silicate treated with palmitic acid or oleic acid, magnesium silicate treated with stearic acid, palmitic acid, or oleic acid, stearic acid, palmitic acid, or oleic acid Since one or more fillers of the treated anhydrous aluminum silicate are blended in an amount of 30 to 70 parts by weight, the amount of the foaming agent blended in the conventional polyvinyl chloride foam is The foaming rate of the conventional polyvinyl chloride foam can be obtained with a smaller blending amount, and the foaming agent decomposition product residue can be reduced to prevent a decrease in electric characteristics.

Here, polyvinyl chloride (PVC) having an average degree of polymerization of 800 to 2,000 is suitable. The fact that the phthalate ester plasticizer is 30 to 100 parts by weight means
This is the general blending amount of the polyvinyl chloride foam. Sn-based stabilizers, Pb-based stabilizers, and Ca-Zn-based stabilizers are conventionally used stabilizers, and 1 to 5 parts by weight is a general stabilizer used in polyvinyl chloride-based foams. It is a suitable amount. Azodicarbonamide (ADCA)
Is a polyvinyl chloride blowing agent. This ADCA is a decomposable foaming agent, which mainly generates N ₂ gas by thermal decomposition, and has been widely used as an inexpensive foaming agent in polyvinyl chloride foams. This ADC
The compounding amount of A is generally 0.1 to 5 parts by weight based on 100 parts by weight of polyvinyl chloride. When the amount of ADCA is 0.1 to 5 parts by weight, if the amount of ADCA is less than 0.1 part by weight, the amount of foaming of polyvinyl chloride is small, and the body does not form as a polyvinyl chloride foam. This is because, even if added in excess of 5 parts by weight, the amount of foaming does not increase in proportion to the amount added, and the amount of metal residues increases, resulting in a decrease in electrical characteristics. Calcium anhydrous magnesium, anhydrous magnesium silicate, and anhydrous aluminum silicate are all fillers, and are surface-treated with stearic acid, palmitic acid, or oleic acid. This stearic acid,
Palmitic acid, anhydrous calcium silicate surface-treated with either oleic acid, anhydrous magnesium silicate,
The filler of anhydrous aluminum silicate is shown in FIGS. That is, the filler 5 is composed of granular (generally having a particle size of 30 to 100 μm) granules 6 of anhydrous calcium silicate, anhydrous magnesium silicate, and anhydrous aluminum silicate.
Is formed by forming a coating film 7 of stearic acid, palmitic acid, and oleic acid on the surface of. These three fillers may be blended alone, or two or three of them may be blended and blended. In this case, the compounding amount is 30 to 70 parts by weight as in the case of the conventional filler. Calcium anhydride, magnesium silicate, and aluminum silicate surface-treated with stearic acid, palmitic acid, or oleic acid increase viscosity when polyvinyl chloride is melted when blended with polyvinyl chloride. There is. This thickening effect increases the shearing force when extruding the polyvinyl chloride resin composition with an extruder, and the temperature of the molten resin is uniformly increased by the shear heat insulation during the extrusion, and the blowing agent is added at the same amount as before. Even with this, a foaming rate higher than the conventional foaming rate can be obtained.

[0011] The amount of 30 to 70 parts by weight of anhydrous calcium silicate, anhydrous magnesium silicate and anhydrous aluminum silicate means that 0.1 to 5 parts by weight of ADCA added to 100 parts by weight of polyvinyl chloride is sufficient. That is, it is a necessary and sufficient addition amount for foaming.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the first and second aspects of the present invention will be described with reference to Tables 1 and 2 in comparison with conventional examples. Example 1 In this example, 60 parts by weight of dioctyl phthalate (DOP), 2 parts by weight of a Pb-based stabilizer, and 100 parts by weight of polyvinyl chloride (specifically, an average degree of polymerization of 1300) were used.
It contains 0.2 parts by weight of CA (azodicarbonamide) and 50 parts by weight of anhydrous calcium silicate. Example 2 In this example, ADCA (azodicarbonamide) was added in 0.1%.
4 parts by weight, and the rest is the same as the first embodiment. Example 3 In this example, ADCA (azodicarbonamide) was added in 0.1%.
6 parts by weight, and the rest is the same as the first embodiment. Example 4 In this example, ADCA (azodicarbonamide) was added to 0.1%.
8 parts by weight, and the rest is the same as Example 1. Example 5 In this example, ADCA (azodicarbonamide) was prepared by adding 1.
Other parts are the same as those in the first embodiment except that they are 0 parts by weight. Comparative Example In this comparative example, 60 parts by weight of dioctyl phthalate (DOP), 2 parts by weight of a Pb-based stabilizer, and 50 parts by weight of anhydrous calcium silicate were used for 100 parts by weight of polyvinyl chloride (specifically, an average degree of polymerization of 1300). Parts by weight, foaming agent AD
It does not contain CA (azodicarbonamide).

Table 1 shows the components of each of Examples 1 to 5 and Comparative Example. Table 1 Table 1 is a composition component table of each example and comparative example.

Conventional Example 1 In Conventional Example 1, 60 parts by weight of dioctyl phthalate (DOP), 2 parts by weight of a Pb-based stabilizer, and 100 parts by weight of polyvinyl chloride (specifically, an average degree of polymerization of 1300) were used.
It contains 0.2 parts by weight of CA (azodicarbonamide) and 50 parts by weight of calcium carbonate. Conventional Example 2 In Conventional Example 2, ADCA (azodicarbonamide) was added in 0.1%.
4 parts by weight, and the rest is the same as Conventional Example 1. Conventional Example 3 In Conventional Example 3, ADCA (azodicarbonamide) was added in 0.1%.
6 parts by weight, and others are the same as the conventional example 1. Conventional Example 4 In Conventional Example 4, ADCA (azodicarbonamide) was added in 0.1%.
8 parts by weight, and others are the same as the conventional example 1. Conventional Example 5 In Conventional Example 5, ADCA (azodicarbonamide) was used.
0 parts by weight, and others are the same as the conventional example 1.

Table 2 shows the composition of each of these Conventional Examples 1 to 5. Table 2 Table 2 is a composition component table of each example and comparative example.

With respect to the vinyl chloride resin compositions based on each of the Examples and Comparative Examples, the foaming ratio and the volume resistivity were measured. The results are shown in Table 3. Table 3 Further, for the vinyl chloride resin composition based on the conventional example, the foaming ratio and the volume specific resistance value were measured. The results are shown in Table 4. Table 4 Examples 1 to 5, Comparative Examples, and Conventional Examples 1 to 5 in Tables 3 and 4
Correspond to the respective composition components shown in Tables 1 and 2.

In measuring the foaming ratio in Tables 3 and 4, first, a sample is prepared using the extruder 8 shown in FIG. The extruder 8 is a full-flight type extruder, and heaters are provided at appropriate locations (in FIG. 4, three locations C ₁ , C ₂ , and C ₃ ).
Is to be heated. In this barrel 9,
A screw 10 is provided. This screw 10
Are formed smaller as the pitch of the wings approaches the tip. Therefore, the molten resin extruded by the screw 10 is extruded in a compressed state. A hopper 11 is provided in the barrel 9, and pellet-shaped resin 12 is charged and sequentially fed into the barrel 9. A head 13 is provided at the tip of the barrel 9, and the molten resin compressed and conveyed by the screw 10 is extruded to form a polyvinyl chloride-based foam 15. The set temperature of barrel 9 is C ₁ point,
C ₂ points, C ₃ points, and a 170 ° C. In terms of the respective heads. The compression ratio of the extruder 8 is a volume ratio (V ₁ / V ₂ ) between the volume V ₁ between the blades of the screw 10 below the hopper 11 and the volume V ₂ between the blades at the tip of the screw 10, and is 1: 1:
3. The rotation speed of the screw 10 is 70 rpm. The pellet-shaped resin 12 housed in the hopper 11 is heated by a heater and compressed by the screw 10 while being conveyed by the screw 10 in the barrel 9, the foaming agent in the resin 12 foams, and polyvinyl chloride is formed. It becomes the system foam 15. The foaming rate of the polyvinyl chloride foam 15 delivered from the head 13 of the barrel 9 is Is required.

In measuring the specific volume resistivity values in Tables 3 and 4, the polyvinyl chloride foam 15 extruded from the extruder 8 was measured at 150 mm × as shown in FIGS.
Formed into a 150mm square, 1mm thick sheet,
A sample 16 is formed. 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 the 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. After a voltage of 500 V is applied for 1 minute between the main electrode 17 and the counter electrode 18 of the sample 16 to which the three electrodes 17, 18, 19 are attached, the sample 16 flows through the sample 16 between the main electrode 17 and the guard electrode 19. The current is measured, and the volume resistivity of the sample 16 is measured by the ammeter 20. This volume specific resistance ρV is Is determined by This volume resistivity value ρV is 1 × 10 ¹² Ω ·
Although it is not an official thing that it is more than cm, it is required in the standard of electric wire. In Table 3, in Comparative Examples in which the foaming agent ADCA (azodicarbonamide) was not blended, the blending amount of the foaming agent was both 0 parts by weight, so that the foaming ratio was 0%. The volume resistivity ρ of this comparative example is 7.9 × 10
^It shows a very high value of ¹³ Ω · cm.

Comparison of Tables 3 and 4 shows that the blowing agent ADC
The foaming ratio of Conventional Example 1 and Example 1 in which both the amounts of A (azodicarbonamide) were 0.2 parts by weight were 9.8 in Conventional Example 1
% In Example 1 was as high as 12.3%, indicating that the foaming efficiency was improved. The volume resistivity value ρ of Conventional Example 1 and Example 1 in which both the compounding amount of the foaming agent ADCA is 0.2 parts by weight is 1.2 × 10 ¹³ Ω · cm in Conventional Example 1, whereas 1 is 0.8 × 10 ¹³ Ω · cm, which is almost the same, but the conventional example 1 is slightly higher. However, Example 1
Is sufficiently higher than the standard. The foaming ratios of Conventional Example 2 and Example 2 in which both the compounding amounts of the foaming agent ADCA (azodicarbonamide) are 0.4 parts by weight are as follows:
It can be seen that the foaming efficiency is considerably improved, with the conventional example 2 being 14.7% and the example 2 being as high as 17.9%. Conventional Example 2 in which both the amounts of the foaming agent ADCA are 0.4 parts by weight.
And the volume resistivity ρ of Example 2 is 7.1 × in the conventional example 2.
In contrast to 10 ¹² Ω · cm, Example 2 has 6.4 × 10 ^12.
Ω · cm, which is slightly higher in Conventional Example 2. However, the volume specific resistance value ρ of Example 2 sufficiently exceeds the standard. Further, the foaming ratios of Conventional Example 3 and Example 3 in which the compounding amount of the foaming agent ADCA (azodicarbonamide) is both 0.6 parts by weight are as follows:
Conventional Example 3 is 18.9%, whereas Example 3 is 25.0%, which is much higher, indicating that the foaming efficiency is greatly improved. The volume resistivity ρ of Conventional Example 3 and Example 3 in which both the compounding amount of the foaming agent ADCA is 0.6 part by weight is 2.8 × 10 ¹² Ω · cm in Conventional Example 3 and 2.8 × 10 ¹² Ω · cm in Conventional Example 3. 3 is 3.4
Example 10 is slightly higher than that of Conventional Example 3 at × 10 ¹² Ω · cm. This is because the amount of foaming by the foaming agent ADCA is large and the residue is small.

The foaming ratio of Conventional Example 4 and Example 4 in which both the compounding amount of the foaming agent ADCA (azodicarbonamide) is 0.8 parts by weight is 21.4% in Conventional Example 4 and in Example 4 It is much higher at 28.3%, indicating that the foaming efficiency has been greatly improved. The volume resistivity value ρ of Conventional Example 4 and Example 4 in which the amount of the foaming agent ADCA was 0.8 parts by weight.
Is 2.3 × 10 ¹² Ω · cm in Conventional Example 4, whereas 3.0 × 10 ¹² Ω · cm in Example 4 is slightly higher in Example 4 than in Conventional Example 4. . Conventional Example 4 and Example 4
In both cases, the value of the volume specific resistance value ρ is lower than that of Conventional Example 3 and Example 3, because the amount of the foaming agent ADCA added to polyvinyl chloride is increased. The reason why the volume specific resistance value ρ of Example 4 is larger than the volume specific resistance value ρ of Conventional Example 4 is that the amount of foaming by the foaming agent ADCA is large and the residue is small. Furthermore, the foaming ratios of Conventional Example 5 and Example 5 in which both the compounding amount of the foaming agent ADCA (azodicarbonamide) is 1.0 part by weight are 22.3% in Conventional Example 5 and 30. 2%
It is clear that the foaming efficiency has been greatly improved. The volume resistivity ρ of Conventional Example 5 and Example 5 in which both the compounding amount of the foaming agent ADCA is 1.0 part by weight is
Is 1.9 × 10 ¹² Ω · cm, whereas that of Example 5 is 2.
Example 5 is slightly higher than 1 × 10 ¹² Ω · cm in Conventional Example 5. The values of the volume resistivity values ρ of the conventional example 5 and the example 5 are lower than those of the conventional example 4 and the example 4, but this is because the foaming agent ADC added to the polyvinyl chloride is used.
This is because the amount of A is increasing. The volume resistivity ρ of the fifth embodiment is the same as the volume resistivity ρ of the fifth prior art.
This is because the amount of foaming by the foaming agent ADCA is large and the residue is small. These foaming agents AD
FIG. 7 shows the change in the foaming rate with respect to the amount of CA added.
FIG. 8 shows the change in the volume resistivity ρ with respect to the amount of DCA added.
Respectively.

[0021]

According to the first aspect of the present invention, the foaming ratio of the conventional polyvinyl chloride foam is reduced by using a smaller amount of the blowing agent than the conventional polyvinyl chloride foam. Can be obtained, and a reduction in the electric characteristics can be prevented by reducing the residue generated by decomposition of the blowing agent. According to the second aspect of the present invention, the foaming rate of the conventional polyvinyl chloride foam can be obtained with a compounding amount smaller than the compounding amount of the blowing agent blended in the conventional polyvinyl chloride foam. In addition, it is possible to reduce a residue generated by decomposition of a foaming agent to prevent a decrease in electric characteristics.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of an insulated wire / cable to which the present invention is applied.

FIG. 2 is a partial cross-sectional perspective view of a filler according to the present invention.

FIG. 3 is a sectional view of the filler shown in FIG. 2;

FIG. 4 is an overall configuration diagram of an extruder;

FIG. 5 is a diagram for explaining a method of measuring a volume resistivity.

FIG. 6 is a diagram showing a relationship with electrodes when measuring the volume resistivity shown in FIG. 5;

FIG. 7 is a graph showing a change characteristic of a foaming ratio with respect to an addition amount of a foaming agent ADCA.

FIG. 8 is a change characteristic diagram of a volume resistivity value ρ with respect to an addition amount of a foaming agent ADCA.

[Explanation of symbols]

1 ……………………………………………………………………………………… Conductor 3 …………………………… Insulator 4 ………… ……… Sheath 5 ……………… Filler 6 ………………… Granules 7 ………………… Coating 8… Extruder 9 Barrel 10 Screw 11 Hopper 12 ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………. Sample 17 …………………………………………………………………………………………………… Counter electrode 19 ……………………… Guard electrode 20 ………………… … Ammeter

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // H01B 7/02 H01B 7/02 G

Claims (2)

(57) [Claims] 1. A polyvinyl chloride resin composition obtained by adding a plasticizer, a stabilizer and a foaming agent to polyvinyl chloride, wherein one or two of anhydrous calcium silicate, anhydrous magnesium silicate and anhydrous aluminum silicate are added. A PVC-based foamed insulating resin composition comprising a filler which has been subjected to a surface treatment with stearic acid, palmitic acid or oleic acid. 2. 100 parts by weight of polyvinyl chloride, 30 to 100 parts by weight of a phthalate ester-based plasticizer, and 1 to 1 part of an Sn-based stabilizer, a Pb-based stabilizer, or a Ca—Zn-based stabilizer.
5 parts by weight, ADCA 0.1 to 5 parts by weight, stearic acid,
Palmitic acid, calcium silicate surface treated with either oleic acid, or magnesium silicate surface treated with stearic acid, palmitic acid, or oleic acid, or any of stearic acid, palmitic acid, oleic acid A PVC foamed insulating resin composition comprising 30 to 70 parts by weight of one or more fillers of anhydrous aluminum silicate surface-treated with 1.