Development of Non-Lead Stabilized PVC Compounds
for Insulated Wires and Cables
by Koichi Mizuno * , Hiroshi Hirukawa * , Osamu Kawasaki *2 ,Hideo Noguchi *3 and Osamu Suzuki *3

With the present trend toward eliminating risks to the environment, electrical appli-

ABSTRACT ance and motor vehicle manufacturers have already taken the lead in promoting

green procurement and eco-projects, giving preference to the purchase of raw materials having
reduced environmental impact. This paper reports on the development of materials using safer Al/
Mg/Ca/Zn-based compounds as stabilizers for the polyvinyl chloride (PVC) used in sheaths forelectrical power cables to replace the lead-stabilized compounds conventionally used. It was confirmed that the materials developed exhibited a level of electrical properties and stabilization equivalent
to that of lead stabilizers. Power wire products too, were confirmed to be equivalent to products
using conventional lead stabilizers in terms of both initial properties and reliability, as shown in longterm tests for resistance to weather and water immersion.

1.

INTRODUCTION

At COP3--Session 3 of the Conference of the Parties tothe U.N. Framework Convention on Climatic Change--heldin Kyoto in December 1997, agreement was reached toreduce emission of carbon dioxide and other greenhousegases by 5% or more, relative to 1990 levels.
Monitoring of organic substances--paricularly heavy
metals--is being similarly strengthened, and the OECD iscontinuing its risk-reduction activities with respect to fivepilot substances: lead, mercury, cadmium, bromine-based
flame retarding agents and methylene chloride.
Influenced by this trend toward eliminating risks to theenvironment, manufacturers of electrical appliances andmotor vehicles are taking the lead in adopting green procurement policies that promote the purchase of raw materials that impose a lower environmental burden, and actively pursuing eco-projects. Environmental concerns obviously impinge on the field of power cables too, and measures are being considered to use lead-free and halogenfree materials for PVC sheaths for motor vehicle wire harnesses, wiring for electrical appliances, and the like. Under these circumstances it will be possible, even in thearea of PVC insulation for power cables, to replace thelead stabilizers used heretofore with compounds that offer even greater safety.

* 1st Development Sec., Hiratsuka Lab., R & D Div.
* 2 Industrial Engineering Sec., Industrial Engineering
Dept., Industrial Cables Div.
* 3 Factory Management Sec., Insulated Wire Production
Dept., Industrial Cables Div.

2.

REGULATIONS GOVERNING LEAD

Table 1 shows the various international and Japanese regulations relating to lead compounds. The only specific international regulations are those under the Basle Treaty,
and the European Association of Consumer Electronics
Manufacturers, as a policy of voluntary restraint, have listed
those purchased substances that impact the environmentand have established standards for content. When a material purchased appears on this list, the supplier is asked
to provide content information. Nearly 50 substances areregistered as impacting the environment, including PVC,
Cd, hexavalent Cr, Pb and Sb.
Within Japan as well, standards regarding harmful substances have become stricter of late, and restriction on
the use of lead and other harmful heavy metals can be
expected to be tightened as time goes on.

3.

PVC MATERIALS AND THEIR STABILIZERSThe substances most commonly used as stabilizers forpolyvinyl chloride are lead-based, and the properties aredescribed below.
3.1 The Function of Stabilizers
Without the addition of a stabilizer, PVC resins begin todegrade at temperatures of 160°C or more, the main reaction being dehydrochlorination. Figure 1 shows the results of measurement of the chlorine in the hydrogen chloride gas produced by the degradation of PVC during heat-111

Table 1

Regulations governing lead

Regulation[Internationally]. Basle Treaty

Provisions

Mandated levels

Regulation of import, export, etc. of harmful waste

Pb and Pb compounds: 0.1%

. EACEM

List of purchased substances impacting theenvironment

Pb and Pb compounds: 100 ppm. IEC Guide 109

Guide to design for the environment (DFE)

Elimination of Pb and otherharmful substances. OECD Risk Reduction

Pb, Cd, Hg methylene chloride and bromine-based
flame retarding agents

Pb not yet decided; toward
voluntary monitoring. ISO 14000

Environment management system[In Japan]. Law for the Preventionof Atmospheric Pollution

Standard local emission levels for lead

10 mg/m3 or less

. Labor Safety and Public
Health Law

Lead concentrations in working environments

0.1 mg/m3 or less

. Law for the Treatment
and Cleaning of Waste
Products

Lead dissolution standards for supervisorytreatment plants

0.3 mg/l or less

. Sewers Law

Standard levels for discharge into sewers

0.1 mg/l or less

. Ministry of Health andWelfare Standards for
Water Quality

Lead concentrations in tap water

0.05 mg/l or less

. Law for the Preventionof Water Pollution

Standard levels for purification of undergroundwater

0.01 mg/l or less

. JIS K 6742

Dissolution of lead from hard PVC water pipes

0.008 mg/l or less

14042: Evaluation of environmental
impact and influence

Sample: 1 g; degradation time: 3 hr

Table 2

Formulation tested

Chlorine generated (Cl/g)

0.8

Parts in formulation

0.7
0.6

Treatment
temperature

0.5

PVC resin(ave. degree of polymerization: 1000)
Plasticizer (DOP)
Calcium carbonate
Paraffin wax
Stabilizer

PVC only

0.4
0.3

100
50
30
0.2
4

with lead stabilizer

0.2
0.1
0
140

160

Figure 1

180

200
220
240
Temperature (˚C)

260

280

Heat degradation of PVC

ing. As can be seen, the addition to the resin of a leadstabilizer reduces the amount of hydrogen chloride produced. As heat degradation proceeds, the resin graduallyshows brown discoloration, eventually becoming black. At
the molecular level, dehydrochlorination causes the formation of double bonds, the cutting of molecular chains,and cross-linking, resulting in a reduction of processability,
together with a degradation in mechanical strength andelectrical properties. Since PVC is generally processed attemperatures between 160°C (at which degradation begins) and 210°C, it is only through the addition of a stabilizer that it can be molded.
3.2 Lead Stabilizers
At present lead stabilizers are commonly used as PVC
stabilizers, and this is particularly true of power cable applications, where lead is used in all but a few specialized
areas. The compounds used include white lead, tribasic
lead sulfate, dibasic lead phthalate, dibasic lead stearate,112

lead stearate and so on. Lead stabilizers are characterized by outstanding thermal stability, low cost, outstanding electrical properties, and by the fact that the lead chloride produced during the stabilization process does notpromote dehydrochlorination1), and there is a need for nonlead stabilizers that can take their place.

4.

TARGETS FOR DEVELOPMENT OF NONLEAD STABILIZERSIn addition to lead stabilizers, there are known to be anumber of stabilizers composed of a plurality of metallic
soaps, such as Cd/Ba, Ba/Zn, Ca/Zn, and so on. It is further known that organotin stabilizers, and specifically mercaptide, have an extremely high stabilizing effect.
The selection of metallic compounds as non-lead stabilizers was based on the fact that their effect on the humanbody is slight, and that there was thus little likelihood of
their becoming subject to regulation in the future. Possible
metals are aluminum, potassium , magnesium, calcium,zinc, etc. Accordingly stabilizers made from these metals
were combined and a PVC resin with a non-lead stabilizer was developed for use in power wire insulation.

Furukawa Review, No. 18. 1999

The project was targeted at developing a non-lead- stabilized formulation that was equal to or better than leadstabilized PVC in terms of:
1. Static and dynamic thermal stability,
2. Electrical properties,
3. Mechanical properties,
4. Tinting, and
5. Processability

5.

ity tests using the Congo red method were carried out at
190°C. For the volume resistivity tests, observations ofchanges in resistivity after heating and immersion in water were also made, in addition to the standard JIS method.
The degree of tinting of the heated samples was measured in terms of the color difference (∆E) compared tothe original samples. Measurements were made using a
JP7200F high-grade spectrum color sensor manufactured
by Color Technology Systems.
In addition to static thermal stability tests using the Congo
red method, dynamic thermal stability tests for evaluatingprocessing stability were carried out using a Labo
Plastomill (30C150) made by Toyo Seiki. Test conditions
were jacket temperature of 210°C and roller speed of 100
rpm. Dynamic thermal stability as used here signifies thetime from the start of the test to the time at which, once
Plastomill torque stabilized, torque began to increase due
to scorching of the material.

DEVELOPMENT OF PVC USING NONLEAD STABILIZERS

5.1 Experimental Methodology
Tests were carried out using a basic formulation of soft
PVC used in insulation for electrical wires (see Table 2).
The lead stabilizers used for comparison were 4 parts eachof tribasic lead sulfate (3PbO.PbSO4H2O) and dibasic lead
stearate (2PbO.Pb(C18H35O2)2).
In terms of sample formulation and test conditions, thetests were conducted fundamentally in accordance withJIS K 6723-1995 (Plasticized polyvinyl chloride compounds), although some changes were made with respect
to measurement times and temperatures. Tests for tensile
strength after heating, however, were carried out after heating at 100°C for 5, 14 and 21 days, and the thermal stabil-

Table 3

5.2 Improvement in Electrical Properties
Table 3 compares the stabilization effect of lead stabilizers with those of an ordinary Ca/Zn stabilizer and of one
type of Al/Mg/Ca/Zn stabilizer. The Ca/Zn stabilizer wasmarkedly inferior to the lead stabilizer in terms of thermal
stability, and volume resistivity, measured at both 30 and
60°C, was also lower. It is therefore impossible, whether in

Comparison of lead and non-lead stabilizers
Type of stabilizer

Property

Unit
Pb

Ca/Zn

Al/Mg/Ca/Zn

Initial tensile strength
Initial elongation
Thermal stability at 180˚C

MPa
%
min.

20
290
315

18
270
170

18
290
475

Volume resistivity
at 30˚C
at 60˚CΩ.cmΩ.cm

6.6E+139.5E+127.0E+124.8E+112.1E+13
1.0E+12

Table 4

Improvement in electrical properties
Type of stabilizer

Property

Unit
Pb

Non-Pb A

Non-Pb B

Non-Pb C

Initial tensile strength
Initial elongation

MPa
%

17
250

18
250

18
250

17
260

After heating at 100˚C for 5 days
Residual tensile strength ratio
Residual elongation ratio

%
%

104
97

103
98

100
97

100
98

2.2

3.3

4.6

3.4

107
90

106
89

107
89

108
89

5.4

9.7

11.9

8.6

%
%

117
80

111
77

112
79

109
84

9.2

19.0

18.8

14.6

Thermal stability at 190˚C

min.

100

210

245

250

Volume resistivity
at 30˚C
at 60˚CΩ.cmΩ.cm

7.2×1013
3.6×1012

2.1×1013
1.0×1012

1.1×1014
1.3×1013

1.4×1014
1.2×1013Ω.cm

3.2×1014

2.9×1014

2.9×1014

2.6×1014∆E * (ab)After heating at 100˚C for 14 days
Residual tensile strength ratio
Residual elongation ratio%%∆E * (ab)After heating at 100˚C for 21 days
Residual tensile strength ratio
Residual elongation ratio∆E * (ab)After heating at 100˚C for 21 days
and immersion in hot water (60˚C)
for 3 days

113

Table 5tivity as the lead stabilizer. The purpose of this test was toinvestigate the effect of the metal chlorides produced during stabilization on the electrical properties.
As has been shown above, non-lead stabilizers B andC both satisfied the development target of electrical properties equivalent to lead stabilizers, whereas both sufferedsomewhat more tinting when heated. Thus it was decided
to select non-lead stabilizer C, which has the lesser discoloration of the two, and to find the optimum formulation
using it.
5.3 Improvement in Dynamic Thermal Stability
It having been established that the non-lead C stabilizer
offers outstanding electrical properties plus thermal stability, tests were carried out to determine dynamic thermal
stability under actual processing conditions.
These tests showed that while, in terms of static stability, the non-lead C stabilizer outperformed lead stabilizers
by a factor of 2.5, it was inferior in dynamic thermal stability tests in which a shear was applied. Accordingly evaluations were carried out on three improved versions of sta0.20

Chlorine generated (Cl/g)

terms of stability during processing or of insulation performance for the wire, to simply substitute it for the lead stabilizer. The Al/Mg/Ca/Zn stabilizer, on the other hand, hadoutstanding static thermal stability, and approached leadin terms of volume resistivity, so that it was decided that it
would serve as the basis for development of a non-leadstabilizer for power wire sheaths.
Since the Al/Mg/Ca/Zn stabilizer was slightly inferior to
the lead stabilizer in terms of volume resistivity, improvements were effected. Table 4 shows the test results. Nonlead stabilizers B and C represent adjustments in the constituents of stabilizer A that influence electrical properties.
The values for initial tensile strength and elongation bytensile tests were substantially the same for all of the stabilizers. Even after heating at 100°C for 21 days, the residual elongation ratios for non-lead stabilizers A throughC were substantially the same as for the lead stabilizer,
demonstrating ample thermal stability. However the color
difference (∆E), which is an index of tinting, was muchgreater for the non-lead stabilizers A through C than thatfor the lead stabilizer.
Thermal stability as measured at 190°C by the Congo
red method, which was 100 min for samples containing
the lead stabilizer, was more than double for all of the nonlead stabilizers. This confirmed that in static thermal stability tests using the Congo red method, the Al/Mg/Ca/Znstabilizer was superior.
Comparing results in the volume resistivity tests, nonlead stabilizer A was lower than the lead stabilizer, andwas below the standard value of 5 x 1013Ω.cm at 30°C
that is mandated for PVC insulation by JIS K 6723. In contrast, non-lead B and C both had higher volume resistivity
than the lead stabilizer. It was also confirmed that evenwhen immersed in water at 60°C for 3 days after the heating test, they maintained virtually the same volume resis-

0.15

0.10

Lead stabilizer

0.05

Non-lead C-2
Ordinary non-lead
0.00
0

100

200

300

400

Time (min)Figure 2

Dehydrochlorination curves at 240°C

Improvement in dynamic thermal stability
Type of stabilizer

Property

Unit
Non-Pb C

Non-Pb C-1

Non-Pb C-2 Non-Pb C-3

Dynamic thermal stability
at 210˚C , 100 rpm

min.

28

19

26

30

31

Initial tensile strength
Initial elongation

MPa
%

21
297

20
313

21
300

21
300

20
303

After heating at 135˚C for 1 day
Residual tensile strength ratio
Residual elongation ratio

%
%

100
92

103
97

99
98

95
101

105
97

6.7

11.7

14.7

15.6

16.5

104
87

103
81

102
81

100
94

102
90

12.5

21

32.5

33.4

34.7

104
71

113
67

111
69

97
77

106
80

16

37.8

39.1

41.4

43.1

1.80E+14

5.40E+13

4.40E+13

4.30E+13

4.50E+13

Degree of discoloration ∆E * (ab)After heating at 135˚C for 2 days
Residual tensile strength ratio
Residual elongation ratio%%

Degree of discoloration ∆E * (ab)After heating at 135˚C for 3 days
Residual tensile strength ratio
Residual elongation ratio%%

Degree of discoloration ∆E * (ab)Volume resistivity
at 30˚C114

Pb stabilizerΩ.cm

Furukawa Review, No. 18. 1999

bilizer C (C-1, C-2 and C-3).
Table 5 shows the results of measurements of dynamic
thermal stability. It can be seen that the value for the leadstabilizer, at 28 min, and non-lead C at 19 min were thereverse of those for static thermal stability using the Congo
red method. But non-lead stabilizers C-1 through C-3
showed improved dynamic thermal stability, with the value
for C-2 somewhat better than that for the lead stabilizer.
Yet for C-2 more than C-1, and even more for C-3, improvements in dynamic thermal stability tended to be accompanied by greater discoloration (∆E). The expression∆E*(ab) in Table 5 represents the difference in color fromthe original, so that a smaller numerical value indicates alower degree of discoloration. It was judged that non-leadC-2 offered the optimum balance.
Table 6

6.

COMPARISON OF HCl UPTAKE

A non-lead stabilized PVC material was successfully developed, having dynamic thermal stability approaching thatof lead-stabilized materials, as determined in sheet property tests and a Labo Plastomill. Here we compare actual
HCl uptake with that of lead stabilizer.
6.1 Measurement Methodology
A material containing the stabilizer was placed in a glass
container, heated to 240°C, and the amount of chlorine
produced was measured in an atmosphere with a nitrogen gas flow of 50 ml/min. The HCl produced by PVC
degradation was trapped in water in the form of chloride
ions, the concentration of which was measured by an ion

Properties of insulated wire (IV 2 mm2)
Type of stabilizer
UnitStandard
Pb

Electrical properties
Withstand voltage 1.5 kV—

Should withstandSpark (7500 V x 0.15 sec)—

Should withstandBreakdown voltage

Non-Pb C-2

kV

—

29

30

MΩ.km

50<

7180

1379

MPa
%

10<
100<

25
330

23
320

After heating at 100˚C for 7 days
Residual tensile strength ratio
Residual elongation ratio%%(5 days)
85<
80<

93
95

97
100

Oil resistance at 70˚C for 4 hrs
Residual tensile strength ratio
Residual elongation ratio%%(tubular)
85<
80<

87
86

93
89

Heating while wound at 120˚C for 1 hr—

Should not crack

Low-temperature winding (-10˚C by JIS)—

Should not crack-40˚C>-40˚C>

Cold-resistance by JIS

˚C

—

-22

-22

Heat shrinkage factor at 100˚C for 1 hr

%

3<

0.1

0.1

Dielectric resistivity at 20˚C
(measured at 25˚C)
Properties of insulation
Initial tensile strength
Initial elongation

Table 7

Properties of insulated cable (XLPE-insulated with PVC sheath, 3-core x 8 mm2)
Type of stabilizer
Unit

Electrical properties
Withstand voltage 1.5 kVStandard
Pb

Non-Pb C-2—

Should withstand

MΩ.km

2000<

∞

∞

MPa
%

10<
120<

19
340

22
320

After heating at 100˚C for 2 days
Residual tensile strength ratio
Residual elongation ratio

%
%

85<
80<

100
97

99
98

Oil resistance at 70˚C for 4 hrs
Residual tensile strength ratio
Residual elongation ratio

%
%

80<
60<

96
89

98
91

Heating while wound at 120˚C for 1 hr—

Should not crack

Cold-resistance by JIS

˚C

-15>

-23

-23

Heat deformation

%

50>

11.3

9.8

Flame retardancy—

Should selfextinguish within
60 secDielectric resistivity at 20˚C
(measured at 25˚C)
Properties of sheath material
Initial tensile strength
Initial elongation

115

Table 8

Properties after accelerated exposure tests

10000

Insulation resistance (MΩ.km)

Type of stabilizer
Property

Unit
Pb

Non-Pb C-2

Initial tensile strength
Initial elongation

MPa
%

24.5
335

23
323

Embrittlement temperature

˚C

-22

-22

Weatherometer for 2000 hr
Residual tensile strength ratio
Residual elongation ratio

%
%

85
90

91
96

Embrittlement temperature

˚C

-8

-7

Lead stabilizer
Non-lead C-2
1000

100

10
0

50

100

150

200

Duration of immersion (days)

Weatherometer for 2500 hr
Residual tensile strength ratio
Residual elongation ratio

%
%

89
90

94
93

Embrittlement temperature

˚C

-8

-6

Insulation resistance (IV 2 mm2) after immersion
in water at 60°C

Figure 3

Table 9Relative dielectric constant9

Properties after outdoor exposure tests
Type of stabilizer

Property

Unit
Pb

Non-Pb C-2

7
Lead stabilizer

Initial tensile strength
Initial elongation

MPa
%

24.5
335

23
323

After outdoor exposure for6 months
Residual tensile strength ratio
Residual elongation ratio

%
%

95
93

96
92

0

Embrittlement temperature

˚C

-17

-22

Figure 4

MΩ.km

514

134

After outdoor exposure for
12 months
Residual tensile strength ratio
Residual elongation ratio

%
%

95
95

99
97

Embrittlement temperature

˚C

-19

-21

MΩ.km

715

167

Dielectric resistivity

6

Non-lead C-2

5
50
100
150
Duration of immersion (days)

200

Relative dielectric constant (IV 2 mm2) after
immersion in water at 60°C

10000

analyzer (Shimadzu PIA-1000).
The tests were carried out with respect to samples containing the reference lead stabilized material and a material containing non-lead C-2 stabilizer, together with theordinary Al/Mg/Ca/Zn stabilizer considered in Table 3,
which had not been optimized as described above withrespect to the formulations considered.
6.2 Measured Results
Figure 2 shows the results. At the elevated temperature of
240°C, dehydrochlorination was already advanced in theordinary Al/Mg/Ca/Zn stabilizer after 60 min. In terms ofthermal stability at 180°C by the Congo red method, it
showed results superior to those of the lead stabilizer. It
would seem either that there was a sudden production of
HCl at the higher temperature, or that it was impossible toadequately suppress the corrosive effect of the ZnCl2 produced. In contrast it can be seen that non-lead C-2 maintained a dehydrochlorination suppression effect equivalent to that of the lead stabilizer even at the higher temperature of 240°C.

Insulation resistance (MΩ.km)

Dielectric resistivity

116

8

1000

100
Lead stabilizer
Non-lead C-2
100

Figure 5

7.

20

40
60
Duration of loading (days)

80

100

Electrical properties after loading with 1 kV in water

EVALUATION OF PROPERTIES OF
INSULATED WIRE

It has thus been confirmed that in terms of thermal stability and electrical properties as measured by sheet tests,
equivalence with lead stabilizer has been maintained. Next,
using actual extrusion facilities, prototype insulated wires
were manufactured using PVC materials containing nonlead C-2, and their usage properties were evaluated incomparison to conventional wire insulated in lead-stabilized PVC.

Furukawa Review, No. 18. 1999

7.1 Manufacture of Prototype Wire
The prototype wires were vinyl-insulated (IV) wire with aconductor size of 2 mm2 and an insulation thickness of
0.8 mm, and cross-linked polyethylene-insulated (XLPE)
3-core wire with a conductor size of 8 mm2 and a vinyl
sheath thickness of 1.5 mm. In both cases, the prototype
exhibited a level of extrudability that was equivalent to thatof lead-stabilized PVC.
7.2 Evaluation of Initial Wire Properties
Tests were carried out in accordance with JIS C 33071993 (600-V polyvinyl chloride insulated wires) and JIS C
3605-1993 (600-V polyethylene insulated cables and 600V cross-linked polyethylene insulated cables). Results areshown in Tables 6 and 7. In both cases, initial properties
satisfied the JIS requirements.
7.3

Evaluation of Long-Term Properties of Insulated
Wire
Insulated wire is a product that has a long service life.
Wires and cables for electric power applications in particular are often used outdoors for long periods, where
they are constantly exposed to sunlight, wind and rain.
The long-term properties of the prototype insulated cables
were therefore evaluated under conditions emulating thissevere environment. The results were as described below.
7.3.1 Tests to Evaluate Weather ResistanceAccelerated exposure tests were carried out using aweatherometer, under conditions set forth in Japan Cable
Standards (JCS #391 (1984)). Sunshine exposure times
were 2000 and 2500 hours, and the tests carried out were
tensile tests and low-temperature embrittlement tests.
Table 8 shows the results. Compared to lead-stabilizedmaterial, equivalent levels of both residual tensile elongation ratio and low-temperature embrittlement were maintained after exposure to sunlight for 2500 hours.
In addition, outdoor exposure tests are being carriedforward at Furukawa Electric's exposure testing facility, anddata has already been obtained for 6 and 12 months. The
exposed wire was subjected to tensile strength tests, lowtemperature embrittlement tests and measurement of dielectric resistivity, and the results are shown in Table 9.
Since the period of exposure is still short, there has been
no major change in either appearance or properties. We
will continue to obtain data for 3 years and 5 years.
7.3.2 Hot water immersion tests
Samples were immersed in water at 60°C for six months,
and observations were made of changes in dielectric resistivity and dielectric constant. This test simulated longterm use under high-humidity conditions or in an adverse
environment exposed to wind and rain, with the objectiveof confirming the influence on electrical properties. Measurements were made according to JIS C 3005. Results
are shown in Figure 3 and 4. Here too it was confirmedthat the properties exhibited were equivalent to those of
the lead-stabilized material used for comparison.

7.3.3 Immersed Loading Tests
To determine the effect of water immersion when loaded,samples loaded with a voltage of 1 kV were immersed inwater for 3 months, and the subsequent effect on electrical properties was investigated. Figure 5 shows results.
Long-term changes in dielectric resistivity showed substantially the same downward trend, and levels were suchas to pose no problem for actual use.

8.

INTRODUCTION OF THE ECO-ACE®
PRODUCT LINEA program to develop a non-lead-stabilized PVC material
that can be used as a replacement for lead-stabilizedmaterial in insulated wire and power cables in terms ofinitial and long-term properties has been completed. Thermal stability, electrical properties, etc. are considered tobe substantially equivalent to those of lead-based materials.
Furukawa Electric has begun marketing the newly developed non-lead stabilized PVC sheathed wire under the"Eco-Ace" name. It is of course equally applicable to anyof the electric power, telecommunications and vinyl cord
applications using PVC insulation or sheathing.

9.

CONCLUSION

This paper has reported the development of a non-leadstabilized PVC material in an effort to eliminate compoundsof lead, a toxic heavy metal, from PVC materials for insulated wire sheathing applications.
In addition to the problem of heavy metals, PVC materials are also beset with problems involving dioxins. At
present there are a number of views on the cause andeffect regarding PVC and dioxins, and no consensus has
been reached3)~5). PVC is 57% chlorine by weight, and thepossibility that this serves as a source of chlorine for dioxins cannot be denied, but conversely it also has a majorrole in safely fixing the chlorine that is a by-product of caustic soda.
PVCs used for electrical wire has a high rate of recovery and recycling, and product life cycles are long. Further, recent technological advances in final processing,making use of PVC as fuel for blast furnaces, raise thepossibility of it being considered more positively from thestandpoint of overall environmental impact. PVC is being
eliminated from beverage containers and the like, but it
may well make new advances in suitable applications.
Finally we would like to thank Prof. Akifumi Ueno of theFaculty of Engineering, Shizuoka University for his cooperation in evaluating the stabilizers.

117

REFERENCES

1) H.O.Writh and H.Andreas; THE STABILIZATION---, 49,(1977), 627.
2) Vinyl Session of the Kinki Chemical Association; Polyvinyl
Chloride, Nikkan Kogyo Shimbun, 1988, 339. (in Japanese)3) Tanaka et al.; Prevention Technology for Dioxin Pollution in
Refuse Disposal, N.T.S. Inc., 1997. (in Japanese)
4) T.Murata; Metropolitan Pharmaceutical Journal, 12, (1990),
No.8, 23. (in Japanese)
5) H.Asai; Polymer Digests, No.8, (1993), 60. (in Japanese)
Manuscript received on July 17, 1998.

118

Furukawa Review, No. 18. 1999