Abstrict Blends of a polyester with a desiccant and one or more of a poly(mono-1-olefin);
a rubbery diene/monovinylarene block copolymer; or a poly(mono-1-olefin)
and a rubbery block copolymer, optionally with a resinous poly(monovinylarene).
Any of these blends can further employ an oil as an additional component.
Claims I claim:
1. The polyester composition consisting essentially of
(a) about 50 to 90 weight percent polyalkylene terephthalate polyester,
(b) rubbery block copolymer, and
(c) desiccant, wherein said desiccant is selected from the group
consisting of calcium oxide, magnesium oxide, strontium oxide, barium
oxide, and aluminum oxide;
optionally further with (f) light mineral oil.
2. The polyester composition consisting essentially of
(a) about 50 to 90 weight percent polyalkylene terephthalate polyester,
(b) rubbery block copolymer,
(c) desiccant, wherein said desiccant is selected from the group
consisting of calcium oxide, magnesium oxide, strontium oxide, barium
oxide, and aluminum oxide; and
(d) poly(mono-1-olefin);
optionally further with (f) light mineral oil.
3. The polyester composition consisting essentially of
(a) about 25 to 75 weight percent polyalkylene terephthalate polyester,
(b) rubbery block copolymer
(c) desiccant, wherein said desiccant is selected from the group
consisting of calcium oxide, magnesium oxide, strontium oxide, barium
oxide, and aluminum oxide;
(d) poly(mono-1-olefin), and
(e) poly(monovinylarene);
optionally further with (f) light mineral oil.
4. The composition according to claim 1 2 or 3 further including
said (f) light mineral oil.
5. The composition of claim 1 employing about 5 to 40 weight percent
(b), and about 3 to 20 weight percent (c); and where present about
0.5 to 5 weight percent (f).
6. The composition of claim 5 employing about 70-85 weight percent
(a), about 10-20 weight percent (b), and about 5-10 weight percent
(c); and where present about 1-2 weight percent (f).
7. The composition of claim 2 employing (a), about 3 to 30 weight
percent (b), about 3 to 20 weight percent (c), and about 3 to 25
weight percent (d); and where present about 0.5 to 5 weight percent
(f).
8. The composition of claim 7 employing about 60 to 80 weight percent
(a), about 10 to 20 weight percent (b), about 5 to 10 weight percent
(c), and about 5 to 10 percent (d); and where present about 1 to
2 weight percent (f).
9. The composition of claim 3 employing (a), about 3 to 30 weight
percent (b), about 3 to 30 weight percent (c), about 10 to 35 weight
percent (d), and about 3 to 30 weight percent (e); and where included
about 0.5 to 5 weight percent (f).
10. The composition of claim 9 employing about 35 to 50 weight
percent (a), about 10 to 20 weight percent (b), about 10 to 20 weight
percent (c), about 20 to 25 weight percent (d), and about 5 to 10
weight percent (e); and where employed about 1 to 2 weight percent
(f).
11. The composition of claim 1 2 3 5 6 7 8 9 or 10 wherein
said (a) is polyethylene terephthalate, and said (c) desiccant is
a calcium oxide.
12. The composition of claim 1 2 3 5 6 7 8 9 or 10 wherein
said (b) is a butadiene/styrene block copolymer, said (a) is polyethylene
terephthalate, and said (c) is a calcium oxide.
13. The composition of claim 2 3 7 8 9 or 10 wherein said
(a) is polyethylene terephthalate, said (d) is a polyethylene, and
said (c) is a calcium oxide.
14. The composition of claim 2 3 7 8 9 or 10 wherein said
(a) is polyethylene terephthalate, said (b) is a butadiene/styrene
block copolymer, said (d) is a polyethylene, and said (c) is a calcium
oxide.
15. The composition of claim 3 9 or 10 wherein said (a) is a
polyethylene terephthalate, said (b) is a butadiene/styrene block
copolymer, said (c) is a calcium oxide, said (d) is a polyethylene,
and said (e) is a polystyrene.
16. The composition of any of claims 5 6 7 8 9 or 10 wherein
said (a) is a PET bottle regrind.
17. A polyester blend composition consisting of:
(a) about 50 to 90 weight percent polyalkylene terephthalate,
(b) about 5 to 40 weight percent rubbery block copolymer of a hydrocarbon
conjugated diene with a monovinylarene, and
(c) about 3 to 20 weight percent of a desiccant selected from the
group consisting of calcium oxide, magnesium oxide, strontium oxide,
barium oxide, and aluminum oxide; and optionally
(f) about 0.5 to 5 weight percent of light mineral oil.
18. A polyester blend composition consisting of:
(a) about 50 to 90 weight percent polyalkylene terephthalate,
(b) about 3 to 30 weight percent of a rubbery block copolymer of
a hydrocarbon conjugated diene with a monovinylarene,
(c) about 3 to 20 weight percent of a desiccant selected from the
group consisting of calcium oxide, magnesium oxide, strontium oxide,
barium oxide, and aluminum oxide, and
(d) about 3 to 25 weight percent of a poly(mono-1-olefin); and
optionally
(f) about 0.5 to 5 weight percent of light mineral oil.
19. A polyester blend composition consisting of:
(a) about 25 to 75 weight percent polyalkylene terephthalate,
(b) about 3 to 30 weight percent of a rubbery block copolymer of
a hydrocarbon conjugated diene with a monovinylarene,
(c) about 3 to 20 weight percent desiccant selected from the group
consisting of calcium oxide, magnesium oxide, strontium oxide, barium
oxide, and aluminum oxide,
(d) about 10 to 35 weight percent of a poly(mono-1-olefin), and
(e) about 3 to 20 weight percent of a polymonovinylarene; and optionally
(f) about 0.5 to 5 weight percent of light mineral oil.
Description FIELD OF THE INVENTION
The invention pertains to improved polyester blends. In another
aspect, the invention pertains to blends of a polyester with a desiccant
and one or more of a poly(mono-1-olefin), a block copolymer of diene/monovinylarene,
and a poly(monovinylarene). In another aspect, the invention pertains
to improved polyethylene terephthalate blends derived from recycling
of PET bottles.
BACKGROUND OF THE INVENTION
A major source of polyester, such as polyethylene terephthalate
(PET), is the recycle of bottles made therefrom. These bottles conventionally
are prepared from a polyethylene terephthalate resin with a base
overlay cup of high density polyethylene (HDPE) resin. Paper labels,
etc. are utilized.
The usual separation plant, such as described in Modern Plastics,
April, 1980 page 82-3 crushes the received material, grinds it,
and separates fines and paper labels through such as fluidized-bed
separation procedures. The remaining materials primarily are polyethylene
and polyethylene terephthalate. Further separatory procedures are
employed to obtain these two materials as separate streams for individual
recycle and reuse.
Recently, a foamed polystyrene wrap-around label has been applied
to the PET body. This presents an additional problem, now adding
a third major different polymer component to be separated.
Another problem experienced in the reuse of polyesters, whether
obtained from PET bottle recycling or other, has been the fact that
the thermoplastic polyesters are subject to hydrolysis in the presence
of moisture when in the molten state during (re)processing. This
hydrolysis results in a marked decrease in molecular weight, which
then is reflected by marked lowering of physical properties, particularly
toughness. To prevent hydrolysis during (re)processing, it has been
necessary to dry the polyester to a moisture content of less than
such as about 0.005 weight percent or less, a difficult procedure
without deteriorating the polyester.
Needed are improved methods of reuse of the tremendous quantities
of PET available in the form of recycle material. This material
is either from recycle of the tremendous use of PET bottles, or
from scrap in primary polyester bottle forming and other purposes.
Just for example, the above referred to Modern Plastics article
indicated an estimated 1.5 billion PET soft-drink bottles shipped
during 1979 accounting for an approximate total of 150000 metric
tons of resin in that single usage. In the intervening time, this
likely has doubled; presenting a large potential area for useful
recycle. Additionally, probably equivalent quantities of PET are
used elsewhere in many other applications presenting equivalent
opportunities for recycle.
BRIEF SUMMARY OF THE INVENTION
I have solved many of the problems in reusing polyesters. My invention
is based on a blend of (a) a polyester and (c) a desiccant.
(A) By blending (a) the polyester with (b) a block copolymer of
a conjugated diene with a monovinylarene, and (c) a desiccant selected
from calcium, magnesium, strontium, barium, or aluminum oxides,
I am able to produce a tough pliable product without the necessity
of any drying, retaining essentially the effective properties of
the polyester.
(B) In a further aspect of my invention, I blend (a) polyester,
(b) the aforesaid block copolymer of a conjugated diene with a monovinylarene,
(c) the aforesaid desiccant, further with (d) a poly(mono-olefin)
such as high density polyethylene. This produces a tough, pliable
product, with useful impact strength and elongation for injection
molding, well suited as a substitute for impact polystyrene, for
example.
(C) In another embodiment of my invention, I blend (a) polyester,
(b) the block copolymer of a conjugated diene with a monovinylarene,
(c) the desiccant, (d) the polymono-1-olefin, preferably high density
polyethylene, and (e) a polymonovinylarene, preferably polystyrene.
In accordance with this aspect of my invention, the product is a
tough, pliable product, suitable for molding of high impact parts.
The product can be prepared from blending, such as by grinding together,
a PET bottle including the base cup and polystyrene label, supplementing
with such added components as necessary for a balanced product,
and including my important additive the conjugated diene/monovinylarene
block copolymer.
(D) In a further embodiment of my invention, I blend (a) the polyester,
(d) the poly(mono-1-olefin), and the (c) desiccant.
In related aspects of any of the above, I further use (f) an oil,
preferably a light mineral process oil.
DETAILED DESCRIPTION OF THE INVENTION
(a) Polyester
The (a) component is any of the polyesters known as polyester resins.
These are described in detail in such as the Condensed Chemical
Dictionary, 7th Edition, by Rose and Rose, pages 758-759 (Reinhold,
N.Y., 1966). These polyesters also are described in such as Block
Copolymers by Allport and Janes (John Wiley, 1973) pages 264 and
following. Polyesters are prepared by esterification procedures,
alcoholysis, acidolysis, ester-ester interchange, or reaction of
acid chloride with alcohol, as described in many publications. Primary
preparation commercially, of course, is by esterification, reaction
of a polyol with a polyacid. Most important of the polyester resins
are those designated as the polyalkylene terephthalates.
Particular types include such as polyethylene terephthalate, polypropylene
terephthalate, polybutadiene terephthalate, and various blends of
the polyalkylene terephthalates or reaction products of a mixture
of reactants. Most important commercially at present are the polyethylene
terephthalate (PET), having a density of the order of about 1.34
to 1.39 g/cc, commonly employed in the PET beverage bottles.
(b) Conjugated Diene Monovinylarene Block Copolymers
The (b) component is a block copolymer of a conjugated diene with
a monovinylarene, with a sufficient balance of conjugated diene:monovinylarene
to be designated as a thermoplastic of rubbery (elastomeric) character.
These block copolymers can be depicted by the formula (AB).sub.n
Y wherein A and B respectively represent segments or blocks of polymonovinylarene
(polymonovinyl-substituted aromatic compound), and polyconjugated
diene, and wherein Y is a residue of a polyfunctional initiator
or a polyfunctional coupling agent. The block copolymers can be
prepared either by polymerization procedures effective to prepare
a linear block structure, or by sequential polymerization procedures
with coupling, all as is well known in the art.
Suitable conjugated dienes are the hydrocarbon conjugated dienes
used alone or in admixture, and containing of the order of 4 to
12 carbon atoms per molecule, more usually 4 to 8 carbon atoms per
molecule, including such as 13-butadiene and isoprene, both of
these presently being preferred, as well as such as 23-dimethyl-13-butadiene,
piperylene, 3-butyl-13-octadiene, and the like.
Among the suitable monovinylarenes are those of 8 to 18 carbon
atoms per molecule, such as the presently preferred styrene, as
well as 3-methylstyrene, 4-n-propylstyrene, 4-cyclohexylstyrene,
4-decylstyrene, 2-ethyl-4-benzylstyrene, 4-p-tolylstyrene, the vinyl
naphthalenes, and the like, alone or in admixture.
Among the presently preferred block copolymers are such as the
butadiene/styrene block copolymers, in which the blocks can be homopolymeric,
or tapered, isoprene/styrene block copolymers of similar nature,
butadiene/styrene/vinyltoluene random block terpolymers, and other
terpolymers such as the butadiene/styrene/alpha-methylstyrene block
terpolymers. Most preferably the block copolymer will have a ratio
of about 50:50 conjugated diene:monovinylarene copolymerized weight
ratio to 75:25 presently preferred about 60:40.
(c) Desiccant
The (c) component is a desiccant capable of absorbing or reacting
with water, and as a desiccated component selected from the group
consisting of calcium oxide, magnesium oxide, strontium oxide, barium
oxide, aluminum oxide, partially hydrated aluminum oxide. Presently
preferred is desiccated calcium oxide.
Presently preferred and available commercially is a commercial
admixture of either about 90 weight percent or 80 weight percent
desiccated calcium oxide and correspondingly 10 or 20 weight percent
of a light mineral process oil employed both to provide a convenient
means of handling the calcium oxide in effectively powdery, yet
easily flowing form as well as a protection of the calcium oxide
from absorbing moisture, thus providing an easily dispersible form
of the calcium oxide in polymers.
(d) Poly(mono-1-olefin)
The (d) component is a poly(mono-1-olefin), such as and presently
particularly preferred a high density or low density polyethylene,
most preferably high density polyethylene. Other poly(mono-1-olefin)s
employable are the normally solid polypropylene, polybutylene, polyisobutylene,
poly(1-pentene), ethylene/butylene copolymers, ethylene/1-hexene
copolymers, and various blends thereof.
It should be noted that the term "polyethylene" in the
industry has come to include a variety of copolymers in which several
significant percents of butylene, isobutylene, or 1-hexene, are
included in the generalized term "polyethylene".
Presently most preferred because of its use as a protective lower
cup exteriorly on PET bottles is a high density polyethylene, of
a density of about 0.93 to 0.97 g/cc.
(e) Poly(monovinylarene)
The (e) component is a poly(monovinylarene) (poly(monovinyl-substituted
aromatic compound)) based on hydrocarbon monovinylarenes. These
are normally solid, resinous materials, well known in the art. Presently
preferred are the commercially available polystyrenes. Alternatively,
useful and suitable materials include such as poly(alpha-methylstyrene),
poly(vinyltoluene), and various blends thereof. Particularly useful
commercial polystyrenes are those having a density of about 1.03
g/cc and a melt flow of such as about 2.5 g/10 min. However, any
of the poly(monovinylarenes) prepared from the monovinylarenes as
detailed above are usable. Many of the poly(monovinylarenes) may
contain as copolymerized components other ethylenically saturated
compounds such as alpha-methylstyrene, acrylonitrile, methacrylates,
and the like.
(f) Light Mineral Oil
The light mineral oil is an optional but desirable component in
any of my blends. A suitable light mineral oil is described as a
primarily paraffic and naphthenic oil derived from crude oil, coal,
oil shale and the like, having an aromatic content of about 10 to
49 percent by weight, a specific gravity of about 0.85 to 0.95
a flash point of about 300.degree. F. to 600.degree. F., and a viscosity
at 100.degree. F. of about 60 to 3500 SUS.
COMPOSITIONS
In my blends, any suitable and effective proportions can be used.
The percentages given below are recommended for most purposes, but
it should be recognized that blends suitable for various applications
can be made outside of the designated ranges.
It is recognized that the percentages in total may total greater
than one hundred percent, but since the composition is limited to
100 percent, an increase in one component then is balanced by a
decrease in one or more other components.
In my composition (A) of (a) polyester, (b) rubbery block copolymer,
and (c) a desiccant, my inventive terblends are chosen in proportion
so as to provide high impact strength, acceptable tensile properties,
and hardness. Presently preferred are weight percentages of such
as (a) about 50-90 weight percent polyester, more preferably about
70-85 weight percent; (b) about 5 to 40 weight percent rubbery block
copolymer, more preferably about 10-20 weight percent; (c) about
3-20 weight percent of the designated desiccant, more preferably
about 5-10 weight percent; and optionally (f) about 0.5 to 5 preferably
about 1-2 weight percent of the light mineral oil.
In the embodiment of my invention (B) employing the (a) polyester,
the (b) rubbery block copolymer, (c) the desiccant, and (d) a poly(mono-1-olefin),
the proportions preferably should be in the order of (a) about 50-90
weight percent polyester, more preferably about 60-80 weight percent;
(b) about 3-30 weight percent of the rubbery block copolymer, more
preferably about 10-20 weight percent; (c) about 3-20 weight percent
of the aforesaid desiccant, more preferably about 5-10 weight percent;
(d) about 3-25 weight percent of the poly(mono-1-olefin), more preferably
about 5-10 weight percent; and, optionally (f) the light mineral
oil in the amount described above, about 0.5 to 5 preferably about
1-2 weight percent.
In the further embodiment (C) including (e) a polymonovinylarene,
presently suggested weight percents are of the order of (a) about
25-75 weight percent polyester, more preferably about 35-50 weight
percent; (b) about 3-30 weight percent rubbery block copolymer,
more preferably about 10-20 weight percent; (c) about 3-20 weight
percent desiccant, more preferably about 10 to 20 weight percent;
(d) about 10-35 weight percent poly(mono-1-olefin), more preferably
about 20 to 25 weight percent, and (e) about 3-20 weight percent
polymonovinylarene, more preferably about 5-10 weight percent; and
optionally (f) about 0.5 to 5 preferably about 1-2 weight percent
of the light mineral oil.
In my blend embodiment (D) including (a) a polyester, (d) the poly(mono-1-olefin),
and (c) the dessicant, the presently suggested weight percents are
of the order of (a) about 50 to 90 more preferably about 80 to
90 weight percent: (d) about 3 to 20 more preferably about 5 to
10 weight percent; and (c) about 3 to 20 more preferably about
5 to 10 weight percent; and optionally (f) about 0.5 to 5 preferably
about 1-2 weight percent.
BLENDING
My blends can be prepared, in any of the embodiments, by any conventional
and suitable means for combining such ingredients, such as solution
blending, milling, batch mixing, continuous extrusion, and the like.
The blends, of course, can contain conventional additives such
as antioxidants, UV stabilizers, pigments, fillers, flame retardants,
and the like, as in known in the arts. The percentages of materials
employed in the suggested and preferred blends are based on the
weight of the total polymeric ingredients plus desiccant plus, where
used, oil. These weights are exclusive of any of the other additives.
Preferably, my blends are prepared from recycled PET beverage bottles,
and effectively eliminate the need for separating bottles, base
cups, polystyrene labels, so-forth, before grinding. The blends
can be prepared by dry blending, followed by subsequent extrusion
at suitable melt temperatures into strands, cooling, cutting into
pellets, and the like.
My blends can be molded by known molding processes, such as injection
molding, into useful high impact resistant articles such as trays,
containers, automotive parts, and the like.
Most usefully, when applied to the present PET composite bottles,
I produce a useful product therefrom, and save considerable effort,
work, and energy requirements otherwise presently consumed in present
efforts to separate the individual components into individual recycle
streams for individual applications. |