Hexanedioic acid polymer with 1,4-dibutanediamine
File No: PLC/42.
Date:
NATIONAL INDUSTRIAL CHEMICALS NOTIFICATION
AND ASSESSMENT SCHEME
FULL PUBLIC REPORT
Hexanedioic acid polymer with 1,4-
dibutanediamine
T h i s Assessment has been compiled in accordance with the provisions of the
Industrial Chemicals (Notification and Assessment) Act 1989 (the Act), and
R e g u l a t i o n s . This legislation is an Act of the Commonwealth of Australia. The
National Industrial Chemicals Notification and Assessment Scheme (NICNAS) is
administered by Worksafe Australia which also conducts the occupational health &
safety assessment. The assessment of environmental hazard is conducted by the
Department of the Environment, Sport, and Territories and the assessment of
public health is conducted by the Department of Health and Family Services.
For the purposes of subsection 78(1) of the Act, copies of this full public report may
b e inspected by the public at the Library, Worksafe Australia, 92-94 Parramatta
Road, Camperdown NSW 2050, between the hours of 10.00 am and 12.00 noon
and 2.00 pm and 4.00 pm each week day except on public holidays.
For Enquiries please contact the Administration Coordinator at:
Street Address: 92 Parramatta Rd Camperdown, NSW 2050, AUSTRALIA
Postal Address: GPO Box 58, Sydney 2001, AUSTRALIA
Telephone: (61) (02) 9577-9466 FAX (61) (02) 9577-9465
Director
Chemicals Notification and Assessment
PLC/42
FULL PUBLIC REPORT
Hexanedioic acid polymer with 1,4-dibutanediamine
1. APPLICANT
Bribros Pty Ltd of 51-57 Buckhurst Street, SOUTH MELBOURNE VIC 3205 has
submitted a notification statement accompanying their application for assessment
of a synthetic polymer of low concern, hexanedioic acid polymer with 1,4-
dibutanediamine.
2. IDENTITY OF THE POLYMER
Chemical Name: hexanedioic acid polymer with 1,4-
dibutanediamine
Chemical Abstracts Service 50327-77-0
(CAS) Registry No.: (previously listed as 50327-22-5)
Other Name(s): poly[imino(1,4-dioxo-1,4-butanediyl)imino-
1,6-hexanediyl], polyamide 4.6, nylon 4.6
Trade Name(s): Stanyl
[NH-(CH2)4-NH-C(O)-(CH2)4-C(O)]n, where
Molecular Formula:
n = 100
Structural Formula:
NH CH2 CH2 CH2 CH2 NH C CH2 CH2 CH2 CH2 C
O O n
Number-Average Molecular
Weight: 40 900
Maximum Percentage of Low
Molecular Weight Species
(Polymers and Oligomers)
(Molecular Weight < 1 000): < 1.0%
(Molecular Weight < 500): < 1.0%
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Table 1: Polymer Constituents
Constituent CAS No. % Weight
hexanedioic acid 124-04-9 60
1,4-butanediamine 110-60-1 40
Means of Identification Fourier Transform Infra-red spectrum
3. PHYSICAL AND CHEMICAL PROPERTIES
Appearance at 20癈 and
101.3 kPa: smooth hard shiny solid
Melting Point/Glass-transition
Temperature: 295癈
1 180 kg/m3
Density:
Water Solubility: insoluble
Partition Co-efficient
(n-octanol/water): not applicable
Hydrolysis as a Function of not applicable until high temperatures
pH: (>80癈 remains slow)
Flammability Limits: see below
Autoignition Temperature: 420癈
Explosive Properties: spark may cause fines to be explosive in
air
(fines to remain < 10 g/m3)
Reactivity: generally inert, may react with some
metallic chlorides and strong oxidising
compounds, soluble in strong acids, very
polar solvents, and cresol, resorcinol and
chloroform.
Particle Size Distribution: extruded cylindrical granules, 2 to 3 mm
range - 祄 diameter, minimal fines as supplied but
may collect during processing
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Comments on Physico-Chemical Properties
Hexanedioic acid polymer with 1,4-dibutanediamine, commercially marketed as
Stanyl, is a nylon plastic formed from non-hazardous monomers. Given its
extremely high molecular weight and the absence of ionisable groups within the
polymer, Stanyl is insoluble in water. The polymer does not contain functional
groups that will readily hydrolyse or further react and hence is biologically inert.
Like many plastics, stanyl possesses electrostatic properties which can assist
sparking. Fines in air may therefore form explosive mixtures. Stanyl hydrolyses
only slowly at higher temperatures in water ( > 80癈). Oxidation occurs very slowly,
assisted by UV and temperature. Stanyl is marketed for its physical toughness,
temperature resistance, and lack of reactivity to be used in physically demanding
situations, eg automobile engine accessories.
4. PURITY OF THE CHEMICAL
Table 2: Maximum Weight-Percentage of Residual Monomers
Residual Monomers CAS No. % Weight
hexanedioic acid 124-04-9 0.01
1,4-butanediamine 110-60-1 <0.0005
Table 3: Maximum Weight-Percentage of Impurities
Impurity CAS No. % Weight
pyrrolidine 123-75-1 0.004
pyrroline 109-66-6 0.04
aminobutyronitrile 32754-99-7 0.001
5. USE, VOLUME AND FORMULATION
Hexanedioic acid polymer with 1,4-dibutanediamine will be imported as
small granules (2-3mm) combined in several formulations with glass fibres
or stainless steel for example, and in polymer mixtures with other plastics,
such as polytetrafluoroethylene and polytribromostyrene. A formulation with
polytribromostyrene and antimony trioxide (7%) is used in flame retardant
grades.
Stanyl is to be remoulded in Australia for automotive and
electrical/electronic components, for example:
a) engine - oil filters, chain tensioners, inlet manifolds, and pushrod
guides
b) transmission - clutch components, gearbox thrust bearings, and
switch housings
c) cooling - radiator end caps
d) electrical - alternator parts, sensors and switches, lighting
components
e) brakes ABS controllers
f) circuit board mounted parts
FULL PUBLIC REPORT 4
Import volumes are expected to progressively increase from 20 tonnes in
the first year to 250 tonnes in the fifth year. At no time is Stanyl expected to
be manufactured in Australia.
6. OCCUPATIONAL EXPOSURE
Stanyl will be imported in hermetically sealed bags shrink-wrapped on pallets in
containerised shipments with other plastic products. Warehouse personnel will
unpack and reload the pallets preserving the hermetic seal to protect the moulding
properties of Stanyl, which is hygroscopic. After shipping to the moulding plants,
Stanyl will be added to hoppers and fed into high temperature injection moulding
systems conventional to the plastics industry.
This process, which involves heating Stanyl to temperatures over 300癈, if not
performed in well ventilated surroundings, may expose workers to fumes of toxic
chemicals, such as antimony trioxide, which is added to fire retardant grades of
Stanyl. Recovery and recycling of unused plastic may involve grinding processes
with the possibility of dust and increased fines.
In the first year the notifiers estimate 10 to 20 people at 3 or 4 sites would be
involved in handling Stanyl. This number does not include end use workers.
Workers involved would include dock, warehouse, transport and plastic moulding
workers. As an end product Stanyl will be handled by automotive, electrical and
electronic industry workers during assembly and repair. Home repair workers and
hobbyists may also be exposed.
7. PUBLIC EXPOSURE
No toxicological data on hexanedioic acid polymer with 1,4-
dibutanediamine was supplied. However the high molecular weight, 40
900, of the notified polymer prevents its absorption across biological
membranes into tissues. The monomeric constituents of the polymer
together are reported to constitute less than 0.02% by weight of Stanyl.
The monomers are not hazardous. Other possible contaminants are
present at less than 0.05% collectively and are not considered to cause
any appreciable exposure.
The notified polymer will not be sold to the public, but plastic articles made
from the notified polymer will be made available to the public, resulting in
some public exposure. However the notified uses of Stanyl as plastic
components in the automobile and electrical industries will limit the nature
of that exposure. Ground water contamination as a result of disposal is
unlikely because of the low water solubility and the high molecular weight
of Stanyl.
Based on the above information, the proposed use of the notified polymer
is not considered to pose a significant threat to public health. If the
FULL PUBLIC REPORT 5
conditions of use are varied such that greater exposure occurred, further
information may be required to assess the hazards to public health.
8. ENVIRONMENTAL EXPOSURE
Release
Release to the environment of the notified polymer as a result of
manufacturing is expected to be minimal. The polymer will be fed
automatically into moulding machinery from a hopper. Sprue will be
reground and reused. Contaminated polymer scraps will be deposited
into municipal landfills. Overall, such waste streams would account for
between 1% (large production runs) and 5% (small production runs) of the
annual throughput (i.e. a maximum of 12.5 tonnes waste polymer to landfill
is possible). Used articles containing the polymer will also eventually be
deposited in landfills.
Fate
In the case of accidental spillage, pellets of the polymer are expected to
remain where they are deposited. Should a spill occur to water, the pellets
should settle onto the bottom sediments, where they could be collected.
Due to the anticipated negligible solubility of the polymer, leaching from
landfill is highly unlikely, and no movement from the landfill site is expected.
The majority of the polymer is not expected to be released to the
environment until it has been moulded into components. Biodegradation is
unlikely. The high molecular weight of the substance also means that
bioaccumulation is not likely to occur.
Surface photodegradation of the finished components is expected with
sunlight, but this is only likely to occur after the product has been disposed
of to landfill, or discarded inappropriately.
9. ASSESSMENT OF ENVIRONMENTAL EFFECTS
No ecotoxicological data were provided which is acceptable for polymers of
low concern with a NAMW > 1 000 according to the Industrial Chemicals
(Notification and Assessment) Act.
10. ASSESSMENT OF ENVIRONMENTAL HAZARD
Disposal of the notified polymer to landfill is unlikely to present a hazard to
the environment as it will be in a pellet form or as a finished product.
Bioconcentration and leaching are both considered to be unlikely to occur,
due to the high molecular weight of the product and its insoluble nature.
Biodegradation of the product is also considered unlikely.
The low environmental exposure of the polymer as a result of the proposed
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use, together with its expected negligible environmental toxicity, indicate that
the overall environmental hazard should be negligible.
11. ASSESSMENT OF OCCUPATIONAL AND PUBLIC HEALTH AND SAFETY
EFFECTS
Hexanedioic acid polymer with 1,4-dibutanediamine is a nylon plastic polymer with
a molecular weight of 40 900. No reactive or charged groups remain in the notified
polymer. The molecular weight and its biological inertness ensure that no
significant amount of the polymer will cross biological membranes or be absorbed
if ingested or inhaled. The residual monomers, in the notified polymer, are not
hazardous and are present at or below 0.01% by weight. Any impurities are also
present at extremely low levels, below any significant exposure.
The notified polymer will be imported as a commercial product, Stanyl, in different
formulations modified by additives to alter the physical properties for particular
uses. Stanyl is packed in hermetically sealed bags containing small granules.
Unless there is an accidental spill, workers or the public will not be exposed to the
notified polymer during importation and transport. The notified polymer, is not
classified as hazardous according to Worksafe Australia criteria.
During processing, Stanyl will be loaded into hoppers and injected at high
temperature into mouldings to make end-use products. Heating to over 300癈
and machining, including regrinding for sprue recovery and recycling, create the
possibilty of occupational exposure via skin, eyes and airways to fumes and dust.
Since the polymer itself is capable of carrying an electrostatic charge, fines may
form dangerously explosive mixtures in air during processing. Physical irritation to
the airways and eyes is also possible due to mechanical irritation. The explosive
danger, alone, necessitates minimum levels of Stanyl dust and electrical
grounding of possible local charge sources.
Workers involved in the processing of Stanyl, should also be aware that there are
health concerns associated with additives used to change its properties as a
plastic product. These include flame retardant grades containing up to 7%
antimony trioxide. The atmospheric occupational exposure standard for antimony
trioxide is 0.5mg/m3 according to Worksafe, Australia National Exposure Standards
for Atmospheric Contaminants (1). The International Agency for Research on
Cancer(IARC) in 1993 listed antimony trioxide as being possibly carcinogenic to
humans (2).
In addition, animal studies, with chronic low exposure to antimony trioxide, have
shown increased eye cataracts in rats (3) and clastogenic effects in mice (4). Two
studies involving workers exposed to antimony trioxide fumes have shown skin
sensitisation or skin reaction including pustules (5,6). These studies in
conjunction with current recommended exposure standards would indicate that
exposure be kept to a minimum and that monitoring of workplace atmosphere
antimony trioxide levels should be conducted wherever the flame retardant grades
FULL PUBLIC REPORT 7
of Stanyl are processed. The Material Safety Data Sheets for such products
contain suitable warnings to the hazardous nature with respect to antimony
trioxide. Flame retardant grades of Stanyl containing more than 1% antimony
trioxide are classified as hazardous according to Worksafe Australia criteria with
danger of irreversible effects (7).
In its final form toxic components of Stanyl will be locked into the plastic matrix and
effectively unavailable to enter the environment. Only at times, of machining and
heating during the moulding process, will there be a risk of exposure to fumes and
fine dust. Good engineering practice, with exhausting of air born material and
adequate ventilation, will limit potential exposure.
The public will come into contact with plastic articles made from the notified
polymer, but the physical properties of the polymer will preclude its absorption
across biologivcal membranes. Under the conditions of use in the automobile
and electrical industries however, significant public exposure to Stanyl products,
containing the notified polymer, is considered unlikely. The proposed use of the
notified polymer is not considered to pose a significant risk to public health.
12. RECOMMENDATIONS
To minimise occupational exposure to Stanyl, the following guidelines and
precautions should be observed:
? It is good work practice to wear industrial clothing which conforms to the
specifications detailed in Australian Standard (AS) 2919 (8) and
occupational footwear which conforms to Australian and New Zealand
Standard (AS/NZS) 2210 (9) to minimise exposure when handling any
industrial chemical;
? Good personal hygiene should be practised to minimise the potential for
inhalation and ingestion;
? A copy of the relevant MSDS should be easily accessible to employees.
Workers should be aware that some products containing the notified polymer , in
particular flame retardant grades, may contain significant levels of antimony
trioxide. The Worksafe Australia document Exposure Standards for Atmospheric
Contaminants in the Occupational Environment: Guidance Note and National
Exposure Standards (1) should be used as a guide in the control of workplace
exposure to antimony trioxide in these preparations. Appropriate personal
protective equipment should be worn where necessary to minimise exposure to
this potentially harmful chemical. Workers producing plastic materials from
antimony trioxide containing Stanyl should take appropriate precautions to
minimise irreversible damage associated with exposure to this possibly
carcinogenic compound.
FULL PUBLIC REPORT 8
13. MATERIAL SAFETY DATA SHEET
The MSDS for products containing the notified polymer were provided in
accordance with the National Code of Practice for the Preparation of Material Safety
Data Sheets (10).
These MSDS were provided by the notifier as part of the notification statement. It is
reproduced here as a matter of public record. The accuracy of this information
remains the responsibility of the notifier.
14. REQUIREMENTS FOR SECONDARY NOTIFICATION
Under the Act secondary notification of Hexanedioic acid polymer with 1,4-
dibutanediamine shall be required if any of the circumstances stipulated under
subsection 64(2) of the Act arise. No other specific conditions are prescribed.
15. REFERENCES
1. National Occupational Health and Safety Commission 1995, `Adopted
National Exposure Standards for Atmospheric Contaminants in the
Occupational Environment', [NOHSC:1003(1995)], in Exposure Standards
for Atmospheric Contaminants in the Occupational Environment: Guidance
Note and National Exposure Standards, Australian Government Publishing
Service Publ., Canberra.
2. Boffetta P., 1993. Carcinogenicity of trace elements with reference to
evaluations made by the International Agency for Research on Cancer.
Scandinavian Journal of Work, Environment & Health. 19 Suppl 1 pp 67-70.
3. Newton P.E et al, 1994, ubchronic and chronic inhalation toxicity of antimony
trioxide in the rat. Fundamental and Applied Toxicology. 22(4), pp 561-576.
4. Gurnani N., Sharma A. and Talukder G. 1993. Comparison of clastogenic
effects of antimony and bismuth as trioxides in mice. Biological Trace
Element Research. 37(2) pp 281-292
5. Motolese A. et al. 1993 Contact dermatitis and contact sensitisation among
enamellers and decorators in the ceramics industry. 28(2) pp5 9-62.
6. White G.P Jr., Mathias G.G. and Davin J.S. 1993 Dermatitis in workers
exposed to antimony in amelting process. J. of Occupational Medicine.
35(4) pp 392-395.
7. National Occupational Health and Safety Commission 1994, Approved
Criteria for Classifying Hazardous Substances [NOHSC:1008(1994)],
Australian Government Publishing Service, Canberra.
8. Standards Australia 1987, Australian Standard 2919-1987, Industrial
Clothing, Standards Association of Australian Publ., Sydney.
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9. Standards Australia/Standards New Zealand 1994, Australian/New Zealand
Standard 2210-1994, Occupational Protective Footwear, Standards
Association of Australia Publ., Sydney, Standards Association of New
Zealand Publ, Wellington.
10. National Occupational Health and Safety Commission 1994, National Code
of Practice for the Preparation of Material Safety Data Sheets
[NOHSC:2011(1994)], Australian Government Publishing Service, Canberra.
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