Polyethylene terephthalate molding resin blends

Glass fiber reinforced polyethylene terephthalate molding resin blends are provided which crystallize rapidly after being injection molded and which have engineering resin performance characteristics. In addition to polyethylene terephthalate and glass fibers, the blends contain an aliphatic polyester, an ionic hydrocarbon polymer, an antioxidant, and, optionally, polythylene and/or a polymeric epoxy compound. The blends can be flame retarded with a brominated polystyrene and an antimonate without substantial loss of, or change in, properties.

This invention lies in the field of glass fiber reinforced polyethylene 
terephthalate molding resin blends. 
Polyethylene terephthalate molding resin blends which are reinforced with 
glass fibers, asbestos fibers, or other fibrous mineral material are 
known, as are polyethylene terephthalate blends which are able to 
crystallize relatively rapidly (as desired) after being injection molded 
into the typical water cooled molds employed in the injection molding 
industry (which attain surface mold temperatures ranging from about 
85.degree. to 110.degree. C.). Oil cooled molds, which have higher mold 
surface temperatures, may, of course, be used if desired. 
It is difficult to get fiber reinforced polyethylene terephthalate molding 
resin blends to display both rapid crystallization characteristics and a 
combination of acceptably high, from a commercial viewpoint, thermal and 
mechanical properties. Thus, even when a particular polyethylene 
terephthalate molding resin blend displays both good crystallization 
characteristics and, after injection molding, some good strength 
characteristics, it may not be suitable for use in many molding resin 
blend applications because it does not also possess other commercially 
required characteristics. For example, apart from crystallization rate, 
for use in so-called engineering resin applications, a glass fiber 
reinforced polyethylene terephthalate molding resin blend needs to have 
the following combination of minimal level resin performance 
characteristics: 
a relatively low flow rate after molding (typically ranging from about 3 to 
about 10 g/10 min. measured at 275.degree. C. using 2.16 kg); 
an adequate combination of minimal physical strength characteristics in a 
molded body at ambient temperatures; for example, a flexural modulus of at 
least about 1.4 million psi, a flexural strength of at least about 27 
thousand psi, a tensile strength at break of at least about 18 thousand 
psi, an elongation at break of at least about 2 percent, an Izod strength 
(notched) of at least about 1.4 ft.lb./in., and an Izod strength 
(unnotched) of at least about 8 ft.lb./in.; 
a heat distortion temperature after molding of at least about 210.degree. 
C. at a load of 1820 kiloPascals (kPa); 
a commercially acceptable molding temperature window as shown, for example, 
by differential scanning calorimeter data, such as follows: 
a Tg of not more than about 75.degree. C. 
a Tcc of not more than about 117.degree. C. 
a Tm of at least about 250.degree. C. 
a Tmc of at least about 200.degree. C., and 
a crystallization window of at least about 47; and 
an ability to produce a molded part which has a smooth, glossy surface 
after such part is removed from a mold which has a mold surface 
temperature at or below about 110.degree. C. 
It is also difficult to get a fiber reinforced polyethylene terephthalate 
molding resin blend which displays an after-molding flow rate which is 
greater than about 10 g/10 min (measured as above indicated). For example, 
one prior art effort to increase flow rate of such a blend is understood 
to have involved water addition thereto in a manner apparently aimed at 
achieving a controlled and limited hydrolysis of the polyethylene 
terephthalate ester linkages. This procedure is considered to be 
unsatisfactory from a practical standpoint because the effect of the water 
is difficult to control, and because a loss of desirable resin blend 
properties seems to be associated with the water addition. 
A fiber reinforced polyethylene terephthalate resin blend intended for 
engineering resin applications and which accordingly has a commercially 
acceptable combination of desirable physical and chemical properties, such 
as the combination above indicated, should also be capable to having flame 
retardant material added thereto in an amount effective for achieving 
flame retardancy without a significant or commercially unacceptable loss 
of properties in such combination. However, in practice, it has proven to 
be difficult indeed to compound a fiber glass reinforced, rapidly 
crystallizable polyethylene terephthalate molding resin blend which not 
only has a commercially suitable combination of properties, but which also 
has the capacity to be diluted by up to about 1/5 or even more with a 
flame retardant system without causing unacceptable adverse changes in 
properties. 
There is a need in the art of reinforced polyethylene terephthalate molding 
resin blends for rapidly crystallizable blends which also have engineering 
resin performance characteristics. Also, there is a need in the art for 
blends of this type which display high after-molding flow rates without 
water addition and without lubricant addition. In addition, it would be 
desirable for such blends to have the capacity to be flame retarded to an 
acceptable extent by the admixture therewith of flame retardant(s) without 
excessive loss of performance characteristics. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a new and improved class 
of glass fiber reinforced polyethylene terephthalate compositions which 
have an excellent combination of rapid crystallization, physical strength, 
flow rates, heat distortion temperatures and molding window temperatures. 
Another object is to provide such a composition which can be easily and 
reliably prepared by melt extrusion. 
Another object is to provide a fiber glass reinforced polyethylene 
terephthalate molding composition which has engineering resin performance 
characteristics and which is rapidly crystallizable, and which has 
outstandingly high after-molding flow rates. 
Another object is to provide such a composition which can be molded by a 
conventional procedure with conventional equipment and still obtain 
engineering resin performance characteristics with rapid crystallization. 
Another object is to provide such a composition which can be flame retarded 
through the addition thereto of further additives which when so added do 
not cause a significant reduction in desired properties. 
Another object is to provide processes for making and using such a 
composition. 
Other and further objects, aims, purposes, features, advantages, 
embodiments, and the like will become apparent to those skilled in the art 
from the teachings of the present specification taken with the appended 
claims. 
The present invention is directed to a class of new and very useful molding 
resin blends of glass fiber reinforced polyethylene terephthalate which 
have: 
(a) a surprising and unexpectedly high after-molding flow rate after being 
injection molded, and 
(b) a surprising and unexpectedly rapid crystallization rate after being 
injection molded--along with acceptable engineering resin performance 
characteristics, such as physical strength, heat distortion, molding 
window, and surface appearance. 
A rapid crystallization rate, among other advantages, permits the 
achievement of rapid mold cycle times, as those skilled in the art will 
readily appreciate. 
A high-molding flow rate among other advantages, permits an injected resin 
to fill all cavities of an intricate mold, as those skilled in the art 
will readily appreciate. 
In addition, the molding resin blends of this invention retain to an 
unexpected and remarkable extent such an acceptable combination of 
performance characteristics when a selected class of flame retardants is 
admixed therewith even up to a level of about 20 weight percent, or even 
somewhat higher, if desired. This achievement with such flame retardants 
is particularly unexpected because various other flame retardants cannot 
even be mixed with a molding resin blend of this invention under extrusion 
mixing conditions without causing a significant and unacceptable 
deterioration of the polyethylene terephthalate matrix resin (for reasons 
which are not now known). 
Although the molding resin blends of this invention use a plurality of 
additives in combination with polyethylene terephthalate, these additives 
coact with each other and with the polyethylene terephthalate as 
demonstrated by the circumstance that the above indicated desired 
combination of engineering resin performance characteristics is not 
achieved unless all such components are present within the respective 
quantity ranges taught. 
Optionally, an additional type of additive can be compounded with a blend 
of this invention to improve further the impact strength properties of a 
product molded body made from an extruded molding resin blend of this 
invention. 
More particularly, the molding resin blends of this invention are 
compositions comprising (on a 100 weight percent total basis): 
(a) from about 30 to about 75 weight percent of polyethylene terephthalate 
having an intrinsic viscosity of at least about 0.25; 
(b) from about 25 to about 65 weight percent of glass fibers having an 
average cross-sectional thickness in the range from about 7 to about 15 
microns and an average length in the range from about 2 to about 8 
millimeters; 
(c) from about 0.5 to about 7 weight percent of aliphatic polyester having 
a number average molecular weight ranging from about 7,500 to about 20,000 
and which is a condensation product of a dialkanoic acid containing from 
about 8 to about 12 carbon atoms per molecule and a dialkanol containing 
from 2 to about 5 carbon atoms per molecule; 
(d) from about 0.1 to about 7 weight percent of a metal salt of an ionic 
hydrocarbon copolymer of an alpha-olefin containing from 2 to 5 carbon 
atoms per molecule and an alpha, beta ethylenically unsaturated carboxylic 
acid containing from 3 to about 5 carbon atoms per molecule in which 
copolymer the carboxyl groups have been at least partially neutralized 
with cations of said metal, said polymer having a molecular weight before 
such neutralization of at least about 3,000, said metal being selected 
from the group consisting of sodium and potassium; 
(e) from about 0.1 to about 1 weight percent of an antioxidant, and 
(f) from 0 to about 3 weight percent of a polyethylene having a number 
average molecular weight in the range from about 500 to about 10,000. 
Preferably, the thus-described blend consists essentially of ingredients 
(a)-(e). 
Optionally, to increase impact strength, such a blend of this invention can 
additionally contain from greater than 0 to about 3 weight percent of a 
polymeric epoxy compound of the type comprised of a condensation product 
of bisphenol A with epichlorohydrin. The average number of repeating units 
of bisphenol A/epichlorohydrin per molecule in such a condensate can range 
from about 0.1 to about 20. 
To flame retard a blend of this invention, one admixes therewith from 
greater than 0 to about 20 weight percent, or even a higher amount if 
desired (as when a change in other molded product properties is not 
objectionable), of a composition consisting essentially of: 
(a) brominated polystyrene having a number average molecular weight ranging 
from about 200,000 to about 400,000, and having a bromine content in the 
range from about 55 to about 75 weight percent (based on total weight of 
the brominated polystyrene), and 
(b) antimonate of at least one metal selected from Group I, Group II, and 
Group VII of the Periodic Table--wherein the weight ratio of said 
brominated polystyrene to said antimonate ranges from about 2:1 to about 
12:1.

DETAILED DESCRIPTION 
The Polyethylene Terephthalate 
The polyethylene terephthalate employed herein has an inherent viscosity of 
preferably at least about 0.25, preferably about 0.4 as measured by ASTM 
D-2857. The polyethylene terephthalate preferably has an upper limit on 
inherent viscosity of about 1.2. Inherent viscosity is measured in a 3:1 
volume ratio of methylene chloride and trifluoroacetic acid at 30.degree. 
C. The polyethylene terephthalate can optionally contain up to 50 percent 
by weight of other comonomers, such as diethylene glycol, glutaric acid, 
polybutylene terephthalate, polyalkylene oxide, cyclohexane dimethanol, 
and other diols. Mixtures of polyethylene terephthalate resins can be 
used. Suitable polyethylene terephthalate polymers are commercially 
available. 
The Glass Fibers 
The glass fibers have an average cross-sectional thickness in the range 
from about 7 to 15 preferably about 8 to about 10 microns and an average 
length in the range from 2 to about 8 millimeters, preferably about 2.5 to 
about 5 millimeters. Such glass fibers are commercially available. 
The Polyester 
Polyesters have a number average molecular weight in the range from about 
7,500 to about 20,000, preferably about 8,000 to about 10,000. Preferred 
dialkanoic acid comonomers for such polyesters contain 8 to 10 carbon 
atoms per molecule and preferred dialkanol comonomers for such polyesters 
contain 3 to 4 carbon atoms per molecule. One presently most preferred 
such polyester is a condensation product of sebacic acid with 1,2 
propanediol. Characteristically, the polyester is in the physical form of 
a liquid at ambient conditions. It is believed that the polyester reacts 
with the resin matrix during extrusion processing conditions. 
The Ionic Hydrocarbon Copolymer 
Representatives of the ionic hydrocarbon copolymer are sodium and/or 
potassium salts of copolymers of such olefins (especially ethylene) with 
acrylic acid, methacrylic acid, or mixtures thereof which are at least 
about 30 percent neutralized. Suitable polymers are commercially 
available. 
The polyester and the ionic hydrocarbon copolymer (also known as ethylene 
acid copolymer or ionomer) are believed to cooperate with one another in a 
synergistic manner when in combination with polyethylene terephthalate to 
induce rapid crystallization of the polyethylene terephthalate when such 
combination is melt injected into a mold having a surface temperature at 
about or under 110.degree. C., and to result in good molded product 
properties. Typical crystallization times with such a mold temperature are 
characteristically not more than about 30 seconds. 
The Polyethylene 
The polyethylene has a number average molecular weight ranging from about 
500 to about 10,000, preferably about 600 to about 3,000. Such polymers 
are commercially available. Representatives include the trademarked 
materials "Epolene N34" or "Epolene C-10" from Eastman Chemical Company 
and "Polywax 500", "Polywax 655", and "Polywax 1000" from Petrolite 
Specialties Polymer Group. 
The Antioxidant 
Many different antioxidants can be used. In general, preferred antioxidants 
are thermally stable at the processing temperature employed. Hindered 
phenol antioxidants are presently preferred. The antioxidant which is 
presently most preferred is available from Ciba-Geigy Corporation as 
"Irganox 1010", the active component of which is believed to be tetrakis 
(methylene 3-[3,5-di-t-butyl-4-hydroxyphenyl]propionate) methane. Other 
suitable antioxidants include: 
(A) Borg Warner's "Ultranox 626" the active agent of which is 
bis[2,4-di-t-butyl phenyl pentaerythritol]diphosphite; 
(B) Ciba-Geigy's "Irganox 259" the active agent of which is 
1,6-hexamethylene bis(3,5-di-t-butyl-4-hydroxy-hydrocinnamate) and/or 
1,6-hexamethylene bis (3-[3,5-di-t-butyl-4-hydroxyphenyl]-propionate); 
(C) Ferro Corporation's "OXI-Chek 116", the active agent of which is 
octadecyl 3,5-di-t-butyl-4-hydroxyhydrocinnamate; and 
(D) Ciba-Geigy's "Irganox 1098", the active agent of which is 
n,n'-hexamethylene bis[3,5-di-t-butyl-4-hydroxyhydrocinnamide]. 
The Polymeric Epoxy Compound 
Such polymers are commercially available. Representatives include the 
trademarked products "Epon 828", "Epon 1001 F", and "Epon 1009 F" 
available from Shell Chemical Company. 
The Brominated Polystyrene 
Preferably, the bromine content is at least about 60 weight percent of such 
polymer. Preferably, such polymer has a number average molecular weight 
ranging from about 200,000 to about 400,000, preferably about 225,000 to 
about 350,000. Such brominated polystyrene is available commercially. 
For purposes of achieving flame retardancy, the combined weight of the 
brominated polystyrene and the antimonate (see below) in a resin blend is 
preferably at least about 4 weight percent of the total resin blend. A 
presently preferred weight ratio of brominated polystyrene to antimonate 
compound(s) from about 3:1 to about 10:1. 
The Antimonate 
A presently particularly preferred antimonate is sodium antimonate although 
zinc antimonate and nickel antimonate and mixtures thereof are also 
preferred. The antimonate is usually employed in a finely-divided 
particulate or powder form. 
Other Additives 
In addition to the components discussed herein, the blends of the invention 
may contain other additives commonly employed (and in the quantities known 
to the art) with polyethylene terephthalate, such as, for examples, 
colorants, mold release agents, tougheners, heat and ultraviolet light 
stabilizers, fillers, and the like. Usually, the total quantity of such 
other additives is not more than about 20 weight percent of a total resin 
blend although higher amounts could be used if desired. 
Preparation 
The blend compositions are prepared by blending together the components by 
any convenient means. For example, dry polyethylene terephthalate can be 
dry mixed in any suitable blender or tumbling means with the other 
components and the resulting mixture melt-extruded. Preferably, the 
polyester is preblended with the glass fibers and then this mixture is 
itself dry mixed with the other additives before melt-extrusion. A 
convenient melt extrusion temperature ranges from about 540.degree. to 
580.degree. F. (282.degree. to 304.degree. C.). The extrudate is 
preferably in a strand form which can be chopped into pellets or the like 
as desired. 
Composition 
The molding resin blend compositions of this invention are summarized by 
the following Table I: 
TABLE I 
______________________________________ 
Quantity (100 wt. % basis) 
I.D. Broad Range 
Preferred Range 
No. COMPONENT wt. % wt. % 
______________________________________ 
1. Polyethylene 30-75 38.4-63.6 
Terephthalate 
2. Glass fibers 25-65 30-45 
3. Polyester 0.5-7 2.7-4.6 
4. Ionic Hydrocarbon 
0.1-7 0.4-0.6 
Copolymer 
5. Polyethylene 0-3 0.1-1.5 
6. Antioxidant 0.1-3 0.4-0.6 
7. Epoxy Compound 0-5 0.5-0.95 
8. (Flame Retardant)* 
0-20 12.5-15.9 
______________________________________ 
*Weight ratio of brominated polystyrene to metal antimonate specified 
above. 
Usage and Characteristics 
The molding resin blend compositions of this invention are conventionally 
moldable and are useful in engineering resin applications as shown by 
their characteristics as illustrated, for example, in Table II below. 
Table II presents properties for resin blends of the invention and molded 
bodies made therefrom which have glass fiber contents ranging from about 
30 to about 45 weight percent (100 weight percent total blend basis). 
Table II demonstrates the rapid crystallization and high after-molding 
flow rates characteristic of these blends. 
A blended, melt extruded, pelletized composition of this invention can be 
conventionally injection molded, for example, using an injection molding 
temperature with range from about 520.degree. to 580.degree. C. 
(271.degree. to 304.degree. C.) into molds typically ranging in surface 
temperature from about 185.degree. to about 230.degree. F. 
(85.degree.-110.degree. C.). 
TABLE II 
__________________________________________________________________________ 
non-flame 
flame 
art recognized 
retarded 
retarded 
engineering resin 
w/out epoxy 
w/out epoxy 
Properties minimal values 
compound.sup.1 
compound.sup.2 
__________________________________________________________________________ 
Flow rate 3-10 23-27 31-58 
after molding 
Strength 
2.1 flexural modulus 
at least 1.4 
1.5-2.1 1.4-2.3 
2.2 flexural strength 
at least 27 
34.0-39.0 
27.9-29.7 
2.3 tensile strength 
at least 18 
20.2-20.9 
18.0-19.7 
(at break) 
2.4 elongation 
at least 2 
4.1-4.9 3.0-3.9 
2.5 Izod (notched) 
at least 1.4 
2.1-2.2 1.4-1.9 
2.6 Izod (unnotched) 
at least 8 
15.9-20.0 
8.2-9.8 
Thermal Characteristics 
3.1 heat distortion 
at least 210 
221-227 212-222 
3.2 DSC 
3.2.1 Tg not more than 75 
73-75 71-72 
3.2.2 Tcc not more than 117 
119-120 117-118 
3.2.3 Tm at least 250 
252-254 253-254 
3.2.4 Tmc at least 200 
205-209 204-206 
3.2.5 Cw at least 47 
48 47-49 
Surface appearance 
smooth & glossy 
smooth & glossy 
smooth & glossy 
Crystalliz. time 
about 30-90 
less than 30 
less than 30 
__________________________________________________________________________ 
Footnotes for Table II: 
.sup.1 Invention blends without flame retardant 
.sup.2 Invention blends with flame retardant 
Comments On Table II 
Item 1: Flow rate (before and after molding) is measured in an extrusion 
plastometer by ASTM procedure D1238 at 275.degree. C. using a 2.16 
kilogram load as grams per 10 minutes. 
Items 2.1 and 2.2: Flexural modulus and flexural strength are each measured 
in accordance with the procedure defined in ASTM D790 in million psi and 
in thousand psi, respectively. 
Items 2.3 and 2.4: Tensile strength at break and elongation at break are 
each measured in accordance with the procedure defined in ASTM D638 in 
thousand psi and in percent, respectively. 
Items 2.5 and 2.6: Izod impact strength both notched and unnotched is 
measured in accordance with the procedure defined in ASTM D256 in 
ft.lb./in. 
Item 3.1: Heat distortion is measured in accordance with the procedure 
described in ASTM D648 in degrees C. at a load of 1820 kiloPascals. 
Item 3.2: "DCS" references thermal data determined by a Differential 
Scanning Calorimeter. 
Item 3.2.1: "Tg" references glass transition temperature, degrees C. 
Item 3.2.2: "Tcc" references the temperature at which an amorphous polymer 
starts to crystallize when heated, degrees C. 
Item 3.2.3: "Tm" references the melt temperature at ambient pressure, 
degrees C. 
Item 3.2.4: "Tmc" references the temperature at which a molten polymer 
starts to crystallize, degrees C. 
Item 3.2.5: "Cw" references the crystallization window as defined by the 
equation: (Tmc-Tcc)/(Tm-Tg) multiplied by 100 (where Tmc, Tcc, Tm, and Tg 
have their above defined meanings). 
Item 5: Crystallization time is measured in seconds. 
The following examples are presented in further illustration of the 
invention and are not to be considered as unduly limiting the scope of 
this invention. 
EXAMPLES 1-10 
The following examples illustrate molding resin blends of this invention 
and their properties. All of the data are based on actual runs, although 
some values are averages of a plurality of runs. 
A series of dry blends were prepared by tumble mixing the respective 
components together, each blend having a composition as summarized in 
Table III below. The polyethylene terephthalate was preliminarily dried 
for about 16 hours at 250.degree. F. (121.degree. C.) in a vacuum oven. 
Each blend was further mixed by being melt extruded through a 38 mm single 
screw extruder at a melt temperature of about 580.degree. F. (304.degree. 
C.). The melt from the extruder was passed through a stranding die and the 
strand was cooled and chopped into pellets. The pellets were dried at 
about 250.degree. F. (121.degree. C.) for about 16 hours in a vacuum oven. 
The dried, chopped strands were molded in a 1.5 ounce injection molding 
machine at approximately 540.degree. F. (282.degree. C.) with a fast ram 
using a delayed injection time of 0.1 second, a hold time of 4 seconds, a 
cool time of 25 seconds, and an open time of 3 seconds. The mold cavity 
surface temperature was 235.degree. F. (113.degree. C.). The objects 
molded include an ASTM standard "dog bone" and an impact bar for Izod 
impact testing, heat distortion testing, and flexural property testing. 
The properties of each resin blend and of objects molded therefrom are 
summarized in Table IV below. These properties show that these blends have 
engineering resin performance characteristics with rapid crystallization 
rates and high after-molding flow rates. 
TABLE III 
__________________________________________________________________________ 
Composition of Examples 1-10 
Composition in Weight Percent 
I.D. 
COMPONENT Example Number 
No. 
Identity footnote 
1 2 3 4 5 6 7 8 9 10 
__________________________________________________________________________ 
1. Polyethylene Terephthalate 
1 63.6 
49.9 
49.0 
38.4 
63.6 
64.2 
64.2 
50.5 
49.6 
39.0 
2. Glass fibers 2 30 45 30 45 30 30 30 45 30 45 
3. Polyester 3 4.6 3.5 3.5 2.7 4.6 4.6 4.6 3.5 3.5 2.7 
4. Ethylene Acid Copolymer 
4 0.6 0.5 0.5 0.4 0.6 0.6 0.6 0.5 0.5 0.4 
5. Antioxidant 5 0.6 0.5 0.5 0.4 0.6 0.6 0.6 0.5 0.5 0.4 
6. Polyethylene 6 0.6 0.6 0.6 0.6 0.6 -- -- -- -- -- 
(Flame retardant) -- -- (15.9) 
(12.5) 
-- -- -- -- (15.9) 
(12.5) 
7. Sodium Antimonate 
7 -- -- 4.0 3.1 -- -- -- -- 4.0 3.1 
8. Brominated Polystyrene 
8 -- -- 11.9 
9.4 -- -- -- -- 11.9 
9.4 
Total Composition Wt. % 
-- 100 100 100 100 100 100 100 100 100 100 
__________________________________________________________________________ 
Table III Footnotes: 
1 The polyethylene terephthalate has intrinsic viscosity of about 0.65. 
2 The glass fibers are obtained from the manufacturer, OwensCorning 
Company under the trade designation 492AA. These fibers are believed to 
have average diameters of about 9 microns and average lengths of about 3 
millimeters. The fibers are initially in the form of clumps. 
3 The polyester is obtained from C. P. Hall Company under the trademark 
"Paraplex G25" and is believed to be a condensation product of sebacic 
acid and 1,2propanediol. The polyester has a numberaverage molecular 
weight of about 8,000. 
4 The ethylene acid copolymer is obtained from Schulman Company under the 
trademark "Formion 105" and is believed to be a copolymer of ethylene and 
methacrylic acid containing about 10 weight percent methacrylic acid whic 
is 50 weight percent neutralized with sodium. This copolymer is believed 
to have a number average molecular weight in excess of 5,000 before salt 
formation. 
5 The antioxidant is obtained from CibaGeigy Corporation under the 
trademark "Irganox 1010" and the active component thereof is believed to 
be tetrakis [methylene 3(3,5-di-t-butyl-4-hydroxyphenyl) propionate] 
methane. 
6 The polyethylene is obtained from Petrolite Speciality Polymers Group 
under the trademark "Polywax 655". The material is a crystalline wax whic 
is believed to have a number average molecular weight of about 700. 
7 The sodium antimonate is obtained from M&T Chemicals under the trademar 
"Thermogard FR". 
8 The brominated polystyrene is obtained from Ferro Corporation under the 
trademark "PyroChek 68PB" and is believed to have a number average 
molecular weight of from about 280,000 to about 300,000. This polymer is 
also believed to have a bromine content of about 68 weight percent (total 
brominated polystyrene weight basis). 
TABLE IV 
__________________________________________________________________________ 
Composition Example Number 
Properties 1 2 3 4 5 6 7 8 9 10 
__________________________________________________________________________ 
Flow rate 23 27 31 58 80 97 108 102 190 108 
after molding 
Strength 
2.1 flexural modulus 
1.5 2.1 1.4 2.3 1.5 1.5 1.5 2.1 1.5 2.3 
2.2 flexural strength 
34.0 39.0 27.9 29.7 34.5 
34.6 
34.8 
39.3 
25.6 
26.8 
2.3 tensile strength 
20.2 20.9 18.0 19.7 22.4 
21.9 
21.9 
24.3 
18.3 
19.0 
(at break) 
2.4 elongation 
4.9 4.1 3.9 3.0 5.2 5.1 4.9 3.9 4.0 3.5 
2.5 Izod (notched) 
2.1 2.2 1.9 1.4 N/D -- -- -- -- -- 
2.6 Izod (unnotched) 
15.9 20.0 9.8 8.2 N/D -- -- -- -- -- 
Thermal Characteristics 
3.1 heat distortion 
221 227 212 222 N/D N/D 230 229 217 220 
3.2 DSC 
3.2.1 Tg 73 75 72 71 74 74 74 74 N/D N/D 
3.2.2 Tcc 119 120 118 117 122 122 121 120 N/D N/D 
3.2.3 Tm 254 252 254 254 254 254 254 253 N/D N/D 
3.2.4 Tmc 205 205 204 206 205 203 206 207 N/D N/D 
3.2.5 Cw 48 48 47 49 46 45 47 48 N/D N/D 
Surface Appearance 
S & G* 
S & G* 
S & G* 
S & G* 
VSD* 
SD* VSD* 
SD* SD* G* 
Crystallization time 
under 30 
under 30 
under 30 
under 30 -- -- -- -- -- 
__________________________________________________________________________ 
*S & G = "smooth and glossy", VSD = "very slightly dull", SD = "slightly 
dull", G = "glossy 
In Table IV, all property items are measured in the same manner and in th 
same units as specified in the comments for Table II above, except flow 
rate examples 5-10 measured at 275.degree. C. using a 5 kilogram load. 
EXAMPLES 11-13 
The following examples illustrate instances where molding resin blends of 
this invention experienced dramatic loss in properties when compounded 
with flame retardants other than those taught herein for the practice of 
this invention. All of the data is based on actual runs, although some 
values are averages of a plurality of runs. 
A series of dry blends were prepared by tumble mixing the respective 
components together, each blend having a composition as summarized in 
Table V below. Each blend was then subjected to a further mixing attempt 
in the same melt extruder operating under similar conditions as specified 
in Examples 1-10 above. In the case of each of these blends, it was found 
that the blend could not be melt extruded due to decomposition in the 
extruder barrel of polyethylene terephthalate polymer, flame retardant(s), 
and perhaps other additives present. The cause of these observed results 
is unknown presently. 
TABLE V 
______________________________________ 
TABLE III: Composition of Examples 11-13 
Composition 
I.D. COMPONENT Example Number 
No. Identify.sup.4 11 12 13 
______________________________________ 
1. Polyethylene Terephthalate 
53.8 53.8 53.8 
2. Glass fibers 30 30 30 
3. Ethylene Acid Copolymer 
0.3 0.3 0.3 
4. Polyester 3.8 3.8 3.8 
5. Antioxidants 0.5 0.5 0.5 
6. Sodium Antimonate 1.4 1.4 1.4 
7. F.R.A..sup.1 9.6 -- -- 
8. F.R.B..sup.2 -- 9.6 -- 
9. F.R.C..sup.3 -- -- 9.6 
Total Composition wt. % 
100 100 100 
______________________________________ 
Table V footnotes: 
.sup.1 F.R.A. (flame retardant A) is tetrabromophthalic anhydride 
.sup.2 F.R.B. (flame retardant B) is phenoxy terminated 
tetrabromobisphenolA 
.sup.3 F.R.C. (flame retardant C) is tetrabromobisphenolA-bis(2 
hydroxyethyl ether) 
.sup.4 The individual components identified in the Table V Examples are 
the same as those identified in the Table III Examples. 
EXAMPLES 14 AND 15 
The procedure of Examples 1 and 3 was repeated except that 1.0 weight 
percent of an epoxy copound ("Epon 828") was added to the initial mixture 
replacing an equal weight of such polyethylene terephthalate. All of the 
results are based on actual runs, although some values are averages of a 
plurality of runs. 
After melt extrusion and injection molding as described for Example 1 and 
3, the molded articles were evaluated and it was found that the properties 
are similar to those for such Examples 1 and 3 except that Izod impact 
strength (notched and unnotched) is improved. 
While this invention has been described in detail for the purpose of 
illustration, it is not to be construed as limited thereby but is intended 
to cover all changes and modifications within the spirit and scope 
thereof.