U.S. patent application number 09/251507 was filed with the patent office on 2002-08-01 for composition of polyester sulfonate salt inomer,polyamide and polyepoxide.
Invention is credited to BASTIAENS, JOSEF H.P., CHISHOLM, BRET J., GALLUCCI, ROBERT R..
Application Number | 20020103294 09/251507 |
Document ID | / |
Family ID | 22952273 |
Filed Date | 2002-08-01 |
United States Patent
Application |
20020103294 |
Kind Code |
A1 |
CHISHOLM, BRET J. ; et
al. |
August 1, 2002 |
COMPOSITION OF POLYESTER SULFONATE SALT INOMER,POLYAMIDE AND
POLYEPOXIDE
Abstract
A thermoplastic resin composition with enhanced elongation and
good appearance comprising a compatible resin blend of a polyester
sulfonate salt ionomer and a polyamide and an effective amount of
at least one difunctional epoxy compound wherein the difunctional
epoxy compound has at least one cyclohexane ring moiety and having
two terminal epoxy functional groups, wherein at least one of the
two terminal epoxy functional groups is a substituent on the at
least one cyclohexane ring moiety; and optionally an effective
amount of a catalyst compound or rubbery impact modifier.
Inventors: |
CHISHOLM, BRET J.; (CLIFTON
PARK, NY) ; GALLUCCI, ROBERT R.; (MT. VERNON, IN)
; BASTIAENS, JOSEF H.P.; (BERGEN OP ZOOM, BE) |
Correspondence
Address: |
CANTOR COLBURN, LLP
55 GRIFFIN ROAD SOUTH
BLOOMFIELD
CT
06002
|
Family ID: |
22952273 |
Appl. No.: |
09/251507 |
Filed: |
February 17, 1999 |
Current U.S.
Class: |
525/65 |
Current CPC
Class: |
C08L 67/02 20130101;
C08L 77/00 20130101; C08L 2666/14 20130101; C08L 63/00 20130101;
C08L 67/02 20130101; C08L 67/02 20130101; C08L 77/00 20130101; C08L
77/00 20130101 |
Class at
Publication: |
525/65 |
International
Class: |
C08L 051/00 |
Claims
1. A thermoplastic resin composition having enhanced elongation and
good appearance comprising a compatible resin blend of a polyester
sulfonate salt ionomer and a polyamide and an effective amount of
at least one difunctional epoxy compound, said at least one
difunctional epoxy compound having at least one cyclohexane ring
moiety and having two terminal epoxy functional groups, wherein at
least one of the two terminal epoxy functional groups is a
substituent on the at least one cyclohexane ring moiety.
2. A thermoplastic resin composition according to claim 1 wherein
at least one difunctional epoxy compound is selected from the group
consisting of bis(3,4-epoxycyclohexyl) adipate; vinylcyclohexene
diepoxide; 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane
carboxylate and mixtures of any of the foregoing.
3. A thermoplastic resin composition of claim 2 wherein said epoxy
compound is present from 0.1-5.0 wt. % based on the total
composition.
4. A thermoplastic resin composition according to claim 3 wherein
said wherein said difunctional epoxy compound comprises
3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate.
5. A thermoplastic resin composition according to claim 1 wherein
the said resin blend comprises about 5 to 95 wt. % polyester
sulfonate salt ionomer as part of resin blend.
6. A thermoplastic resin composition according to claim 1 wherein
said polyester ionomer comprises an alkylene aryl polyester
copolymers having metal sulfonate units represented by the formula
IA: 4or the formula IB: (M.sup.+n O.sub.3S).sub.d--A--(OR"OH).sub.p
where p=1-3, d=1-3, p+d=2-6, n=1-5, M is a metal, and A is an aryl
group containing one or more aromatic rings where the sulfonate
substituent is directly attached to an aryl ring, R" is a divalent
alkyl group and the metal sulfonate group is bound to the polyester
through ester linkages.
7. A thermoplastic resin composition according to claim 6 wherein
p=2, d=1, and M is an alkaline or alkaline earth metal.
8. A thermoplastic resin composition of claim 6 where the metal
sulfonate polyester copolymer (a) has the formula III: 5where the
ionomer units, x, are from 0.1-50 mole %, R is halogen, alkyl,
aryl, alkylaryl or hydrogen, R.sup.1 is derived from a diol
reactant comprising straight chain, branched, or cycloaliphatic
alkane diols and containing from 2 to 12 carbon atoms, A.sup.1 is a
divalent aryl radical.
9. A thermoplastic resin composition of claim 8 wherein R is
hydrogen, x=1.0-10 mole percent, R.sup.1 is C.sub.2-C.sub.8 alkyl,
and Al is derived from iso- or terephthalic acid or a mixture of
the two.
10. A thermoplastic resin composition of claim 8 wherein the metal
sulfonate polyester of formula III is a alkylene polyester wherein
Al is the residue from a diacid component of iso or tere phthalic
acid and derivatives thereof and R.sup.1 is the residue from a diol
component selected from the group consisting essentially of
ethylene glycol, propanediol, butanediol, or cyclohexanedimethanol,
and derivatives thereof.
11. A thermoplastic resin composition according to claim 1 having
an additional alkylene aryl polyester with repeating units of the
following general formula: 6wherein n is an integer of from 2 to 6
and R is a C.sub.6-C.sub.20 aryl radical comprising a
decarboxylated residue derived from an aromatic dicarboxylic
acid.
12. A thermoplastic resin composition according to claim 11 wherein
the polyesters are polybutylene terephthalate and polyethylene
terephthalate.
13. A thermoplastic resin composition of claim 1 wherein said blend
further comprises an impact modifier.
14. A thermoplastic resin composition of claim 13 wherein the
impact modifiers is present in an amount less than about 1 to about
25% by weight.
15. A thermoplastic resin composition of claim 13 wherein said
impact modifier is selected from the group consisting of: MBS, SEBS
and SEBS graft MA.
16. A thermoplastic resin composition according to claim 1
containing an effective amount of a catalyst.
17. A composition of claim 16 wherein the effective catalyst is a
metal halide, metal carboxylate, metal carbonate or metal
bicarbonate.
18. A composition of claim 16 wherein the effective catalyst is
present from 0.01 to 1.0 wt. % of the composition.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a molding composition comprising a
polyester ionomer resin and a polyamide resin.
BACKGROUND OF THE INVENTION
[0002] Blending of an aromatic polyester resin and a polyamide
resin offers the advantage of reduced moisture absorption compared
to pure polyamide and higher heat compared to pure aromatic
polyester. However, such blends are incompatible resulting in poor
surface appearance, delamination, poor ductility, and difficult
injection molding. The advantage of incorporating sulfonate salt
groups into a poly(1,4-butulene terephthalate) polyester is that
the sulfonate groups impart inherent compatibility between the
sulfonated polyester ionomer and polyamide resulting in improved
surface appearance, reduced delamination, and improved
processability. However the blends still are britt;e with poor
elongation.
[0003] U.S. Pat. No. 4,097,446 to Abolins and Holub discloses a
wide variety of blends of different thermoplastic resins with a
very rapidly crystallizing polyester; namely polybutylene
terephthalate and fiber glass. Nylon is shown as an example of a
suitable blend resin. Fiber glass is important in obtaining
improved processability.
[0004] U.S. Pat. No. 5,300,572 to Tajima, et al. relates to
moldable polyester resin compositions which include the resin
components: (A) between 2 to 98% by weight of a compatibilizing
metal sulfonate group-containing aromatic polyester copolymer which
is the polycondensation reaction product of (a) an aromatic
dicarboxylic acid or its ester-forming derivative, (b) a diol
compound or its ester-forming derivative, and (c) an ester-forming
compound containing a metal sulfonate group; (B) between 2 to 98%
by weight of an additive resin which is one of (B-I) an olefin
copolymer which is the copolymerization reaction product between an
olefin with at least one of an alpha.beta.-unsaturated carboxylic
acid or its derivative and a vinyl alcohol or its ester, and (B-II)
a polyamide resin; and, optionally (C) between 0 to 96% by weight
of a non-compatibilizing aromatic polyester resin.
[0005] As set forth in Tajiima, et al. the modified aromatic
polyester copolymer having metal-sulfonate-containing units
introduced into the copolymer's backbone structure of aromatic
polyester copolymer is compatible with both polyolefin and
polyamide resins, and serves as a compatibilizer when an unmodified
(i.e., one not containing metal-sulfonate units) aromatic polyester
is further blended with the modified polyester copolymer and either
a polyolefin or a polyamide resin.
[0006] A problem with blends of comprising a polyester ionomer
resin and a polyamide resin is the lack of ductility. Despite
improved compatibilization of the polyamide blend with the
polyester sulfonate salt, leading to finer morphology and better
appearance than a blend of nylon with a standard thermoplastic
polyester, the blends show poor elongation and impact. The melt
strength is also deficient for processes like blow molding, profile
extrusion and thermoforming. An additional problem may be
encountered if the polyester ionomer and polyamide resin blend is
not dried well before processing. Hydrolysis may cause molecular
weight degradation which also may result in a reduction in
mechanical properties.
[0007] Accordingly, there is a need for improved polyester resin
compositions which exhibit improved elongation, good appearance and
good melt processing capability.
SUMMARY OF THE INVENTION
[0008] We have found that modification of a blend of an aromatic
metal sulfonate co-polyester resin and a polyamide resin with an
effective amount of at least one difunctional epoxy compound
results in improved polyester resin compositions which exhibit
consistent and uniform properties, improved elongation at break and
good appearance. The resulting blends have good chemical
resistance, mechanical properties along with good processability
and reduced moisture absorbance.
[0009] In accordance with the present invention, there is provided
a thermoplastic resin composition having improved elongation and
temperature resistance comprising a compatible resin blend of a
polyester ionomer and a polyamide and an effective amount of at
least one difunctional epoxy compound, said at least one
difunctional epoxy compound having at least one cyclohexane ring
moiety and having two terminal epoxy functional groups, wherein at
least one of the two terminal epoxy functional groups is a
substituent on at least one cyclohexane ring moiety; and optionally
an effective amount of a catalyst compound.
[0010] According to the preferred embodiments, a functional
sulfonate salt "ionomer" group is incorporated into the polyester
so that a blends of polyester ionomer have improved properties as
compared to blends not utilizing the polyester ionomer and not
having the epoxy additive.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0011] The term polyester ionomer, or sulfonate polyester or metal
sulfonate polyester, refers to polyester polymers derived from the
reaction residue of an aryl carboxylic sulfonate salt, an aromatic
dicarboxylic acid, an aliphatic diol or any of their ester forming
derivatives. The ionomer polyester polymers comprise some
monovalent and/or divalent sulfonate salt units represented by the
formula IA: 1
[0012] or formula IB:
(M.sup.+O.sub.n3S).sub.d--A--(OR"H).sub.p
[0013] wherein p=1-3; d=1-3, and p+d=2-6, and A is an aryl group
containing one or more aromatic rings: for example, benzene,
naphthalene, anthracene, biphenyl, terphenyl, oxy diphenyl,
sulfonyl diphenyl or alkyl diphenyl, where the sulfonate
substituent is directly attached to an aryl ring. These groups are
incorporated into the polyester through carboxylic ester linkages.
The aryl groups may contain one or more sulfonate substituents;
d=1-3 and may have one or more carboxylic acid linkages; p=1-3.
Groups with one sulfonate substituent (d=1) and two carboxylic
linkages (p=2) are preferred. M is a metal, n=1-5. Preferred metals
are alkaline or alkaline earth metals where n=1-2. Zinc and tin are
also preferred metals. R" is a alkyl group, for example,
--CH.sub.2CH.sub.2--, --CH.sub.2CH.sub.2OCH.sub.2CH.sub.2--,
--CH(CH.sub.3)CH.sub.2--, --CH.sub.2CH.sub.2CH.sub.2--,
--CH.sub.2CH.sub.2CH.sub.2CH.sub.2--.
[0014] Typical sulfonate substituents that can be incorporated into
the metal sulfonate polyester copolymer may be derived from the
following carboxylic acids or their ester forming derivatives;
sodium sulfo isophthalic acid, potassium sulfo terephthalic acid,
sodium sulfo naphthalene dicarboxylic acid, calcium sulfo
isophthalate, potassium 4,4'-di(carbomethoxy) biphenyl sulfonate,
lithium 3,5-di(carbomethoxy)ben- zene sulfonate, sodium
p-carbomethoxy benzene sulfonate, dipotassium
5-carbomethoxy-1,3-disulfonate, sodio 4-sulfo
naphthalene-2,7-dicarboxyli- c acid, 4-lithio
sulfophenyl-3,5-dicarboxy benzene sulfonate,
6-sodiosulfo-2-naphthyl-3,5-dicarbomethoxy benzene sulfonate and
dimethyl 5-[4-(sodiosulfo) phenoxy] isophthalate. Other suitable
sulfonate carboxylic acids and their ester forming derivatives are
described in U.S. Pat. Nos. 3,018,272 and 3,546,008 which are
included herein by reference. The most preferred sulfonate
polyesters are derived from sodium 3,5-dicarbomethoxy benzene
sulfonate.
[0015] Preferred ionomer polyester polymer comprises divalent
ionomer units represented by the formula II: 2
[0016] wherein R is hydrogen, halogen, alkyl or aryl, and M is a
metal.
[0017] The most preferred polyester ionomer has the formula III:
3
[0018] where the ionomer units, x, are from 0.1-50 mole percent of
the polymer with 1.0 to 20 mole percent being preferred. Most
preferably R is hydrogen. When R is hydrogen, A.sup.1 is phenylene,
and R.sup.1is an alkylene radical of from C.sup.1-C.sup.12,
preferably from C.sup.2 or C.sup.4, and x and y are in mole
percent, then x is from about 1 to about 20 percent, and more
preferably from about 1 to about 10 percent.
[0019] Typical glycol or diol reactants, R.sup.1, include straight
chain, branched, or cycloaliphatic alkane diols and may contain
from 2 to 12 carbon atoms. Examples of such diols include but are
not limited to ethylene glycol; propylene glycol, i.e., 1,2- and
1,3-propylene glycol; butane diol, i.e., 1,3- and 1,4-butane diol;
diethylene glycol; 2,2-dimethyl-1,3-propane diol; 2-ethyl,
2-methyl, 1,3-propane diol; 1,3- and 1,5-pentane diol; dipropylene
glycol; 2-methyl-1,5-pentane diol; 1,6-hexane diol; dimethanol
decalin, dimethanol bicyclo octane; 1,4-cyclohexane dimethanol and
particularly its cis- and trans-isomers; triethylene glycol;
1,10-decane diol; and mixtures of any of the foregoing. A preferred
cycloaliphatic diol is 1,4-cyclohexane dimethanol or its chemical
equivalent. When cycloaliphatic diols are used as the diol
component, a mixture of cis- to trans-isomers may be used, it is
preferred to have a trans isomer content of 70% or more. Chemical
equivalents to the diols include esters, such as dialkyl esters,
diaryl esters and the like.
[0020] Examples of aromatic dicarboxylic acid reactants, as
represented by the decarboxylated residue A.sup.1, are isophthalic
or terephthalic acid, 1,2-di(p-carboxyphenyl)ethane,
4,4'-dicarboxydiphenyl ether, 4,4' bisbenzoic acid and mixtures
thereof. All of these acids contain at least one aromatic nucleus.
Acids containing fused rings can also be present, such as in
1,4-1,5- or 2,6-naphthalene dicarboxylic acids. The preferred
dicarboxylic acids are terephthalic acid, isophthalic acid or
mixtures thereof.
[0021] The most preferred ionomer polyesters are poly(ethylene
terephthalate) (PET) ionomers, and poly(1,4-butylene terephthalate)
ionomers, (PBT), and (polypropylene terephthalate) (PPT)
ionomers.
[0022] Also contemplated herein are the above polyester ionomers
with minor amounts, e.g., from about 0.5 to about 15 percent by
weight, of units derived from aliphatic acid and/or aliphatic
polyols to form copolyesters. The aliphatic polyols include
glycols, such as poly(ethylene glycol) or poly(butylene glycol).
Such polyesters can be made following the teachings of, for
example, U.S. Pat. Nos. 2,465,319 and 3,047,539.
[0023] The preferred poly(1,4-butylene terephthalate) ionomer resin
used in this invention is one obtained by polymerizing an ionomer
component comprising a dimethyl 5-sodium
sulfo-1,3-phenylenedicarboxylate, from 1 to 10 mole %, a glycol
component of at least 70 mole %, preferably at least 90 mole %, of
tetramethylene glycol and an acid component of at least 70 mole %,
preferably at least 90 mole %, of terephthalic acid, and
polyester-forming derivatives therefore.
[0024] The glycol component should contain not more than 30 mole %,
preferably not more than 20 mole %, of another glycol, such as
ethylene glycol, trimethylene glycol, 2-methyl-1,3-propane glycol,
hexamethylene glycol, decamethylene glycol, cyclohexane dimethanol,
or neopentylene glycol.
[0025] The acid component should contain not more than 30 mole %,
preferably not more than 20 mole %, of another acid such as
isophthalic acid, 2,6-naphthalene dicarboxylic acid,
1,5-naphthalene dicarboxylic acid, 4,4'-diphenyldicarboxylic acid,
4,4'-diphenoxyethane dicarboxylic acid, p-hydroxy benzoic acid,
sebacic acid, adipic acid and polyester-forming derivatives
thereof.
[0026] It is also possible to use a branched polyester ionomers in
which a branching agent, for example, a glycol having three or more
hydroxyl groups. Furthermore, it is sometimes desirable to have
various concentrations of acid and hydroxyl end groups on the
polyester, depending on the ultimate end-use of the
composition.
[0027] In some instances, it is desirable to reduce the number of
acid end groups, typically to less than about 30 micro equivalents
per gram, with the use of acid reactive species. In other
instances, it is desirable that the polyester has a relatively high
carboxylic end group concentration.
[0028] Blends of polyesters ionomers with non sulfonate salt
polyesters may also be employed as the polyester ionomer
composition. For example, the invention may consist of a blend of
sulfonate salt PBT and the unmodified PBT resin. Preferred non
sulfonate salt polyesters are the alkylene phthalate
polyesters.
[0029] It is preferred that the sulfonate salt polyester be present
in amounts greater than or equal to the non sulfonate salt
polyester.
[0030] Overall the blend can have from 5-95 wt. % polyamide and
95-5 wt. % total polyester where at least 20 wt. % and preferably
greater than or equal to 50 wt. % of the polyester is sulfonate
salt polyester copolymer.
[0031] The polyamide component of the resin blend comprises a
suitable polyamide. Typical polyamide resins include polyamide-6,
polyamide-6,6, polyamide-11, polyamide-12, polyamide-4,6,
polyamide-6,10 and polyamide-6,12, as well as polyamides prepared
from terephthalic acid and/or isophthalic acid and
trimethylhexamethylenediamine; from adipic acid and
m-xylylenediamines; from adipic acid, azelaic acid,
2,2-bis-(p-aminocyclohexyl) propane, and from terephthalic acid and
4,4'-diaminodicyclohexylmethane. Mixtures and/or copolymers of two
or more of the foregoing polyamides or prepolymers thereof,
respectively, are also within the scope of the present
invention.
[0032] Furthermore, the polyamides may be made by any known method,
including the polymerization of a monoamino monocarboxylic acid or
a lactam thereof having at least 2 carbon atoms between the amino
and carboxylic acid group, of substantially equimolar proportions
of a diamine which contains at least 2 carbon atoms between the
amino groups and a dicarboxylic acid, or of a monoaminocarboxylic
acid or a lactam thereof as defined above, together with
substantially equimolar proportions of a diamine and a dicarboxylic
acid. The dicarboxylic acid may be used in the form of a functional
derivative thereof, for example, a salt, an ester or acid
chloride.
[0033] A detailed description of polyamides and polyamide presursor
materials is provided in U.S. Pat. No. 4,755,566 to Yates. Other
useful polyamides often referred to as "Nylons" are disclosed in
U.S. Pat. Nos. 4,732,938 to Grant et al., 4,659,760 to Van der
Meer, and 4,315,086 to Ueno et al., each also incorporated herein
by reference. The polyamide used may also be one or more of those
referred to as "toughened nylons", which are often prepared by
blending one or more polyamides with one or more polymeric or
copolymeric elastomeric toughening agents. Examples of these types
of materials are given in U.S. Pat. Nos. 4,174,358; 4,474,927;
4,346,194; 4,251,644; 3,884,882; 4,147,740; all incorporated herein
by reference.
[0034] The preferred polyamides for this invention are polyamide-6;
6,6; 6,12; 11 and 12, with the most preferred being
polyamide-6,6.
[0035] The resin blend includes an effective amount of at least one
difunctional epoxy compound. The preferred difunctional polyepoxy
compound is 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane
carboxylate. The preferred catalysts are salts of aliphatic or
aromatic carboxylic acids.
[0036] The epoxy component is at least one difunctional epoxy
compound. By difunctional epoxy compound is meant a compound having
two terminal epoxy functionalities. Preferably the compound will
contain only carbon, hydrogen and oxygen. The compound will
preferably have a molecular weight of below about 1000 to
facilitate blending with the polyester resin.
[0037] Preferred difunctional epoxy compounds will have at least
one of the epoxide groups on a cyclohexane ring. Examples of
preferred difunctional epoxy compounds are
3,4-epoxycyclohexylmethyl-3,4-epoxycyclo- hexane carboxylate,
bis(3,4-epoxycyclohexyl) adipate, vinylcyclohexene di-epoxide,
epoxy cyclohexane adducts of carboxylic acids and the like.
Especially preferred is
3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate.
[0038] The difunctional epoxide compounds can be made by techniques
well known to those skilled in the art. For example, the
corresponding alpha, beta.-dihydroxy compounds can be dehydrated to
produce the epoxide groups, or the correspondingly unsaturated
compounds can be epoxidized by treatment with a peracid, such as
peracetic acid, in well-known techniques. The compounds are also
commercially available.
[0039] The difunctional epoxy compound may be employed in any
effective amount, but preferably small amounts are use, e.g., at a
range of about 0.1 to about 5 percent by weight. However, a
particularly preferred range is from about 0.1 to about 3.5 percent
by weight. A more preferred range is from about 0.5 to about 2
percent by weight. Within this particularly preferred range it has
been found advantageous to employ in certain compositions from
about 1 to about 2.0 percent by weight of the difunctional
polyepoxy compound. All percentages are based on the total weight
of the blend.
[0040] Another optional component of the present invention consists
of the catalyst compound. Preferred catalysts are salts free from
direct carbon-phosphorous bonds and containing at least one of
alkali metal cations and halide anions. It is apparent that this
class contains a large number of compounds. They include alkali
metal halides, alkali metal carboxylates, and alkali metal
carbonates and bicarbonates.
[0041] Illustrative compounds within this class are lithium
fluoride, lithium iodide, potassium bromide, potassium iodide,
sodium acetate, sodium benzoate, sodium caproate, sodium stearate,
and potassium oleate.
[0042] The catalyst component can be present in the composition of
the present invention in any effective amount. Preferably the
catalyst is present in an amount ranging from about 0.01 to about 1
weight percent, more preferably from about 0.03 to about 0.1 weight
percent based on the total weight of the resin composition.
[0043] The composition may optionally contain impact modifiers such
as a rubbery impact modifier. Preferably such impact modifiers are
utilized in an amount less than about 30%, and preferably from 1 to
25% by weight, more preferably less than about 20 percent, even
more preferably less than about 15 percent by weight based on the
total weight of the composition. Typical impact modifiers are
derived from one or more monomers selected from the group
consisting of olefins, vinyl aromatic monomers, acrylic and
alkylacrylic acids and their ester derivatives as well as
conjugated dienes. Especially preferred impact modifiers are the
rubbery high-molecular weight materials showing elasticity at room
temperature. They include both homopolymers and copolymers,
including random, block, radial block, graft and core-shell
copolymers as well as combinations thereof. Suitable modifiers
include core-shell polymers built up from a rubber-like core on
which one or more shells have been grafted. The core typically
consists substantially of an acrylate rubber or a butadiene rubber.
One or more shells typically are grafted on the core. The shell
preferably comprises a vinylaromatic compound and/or a vinylcyanide
and/or an alkyl(meth)acrylate. The core and/or the shell(s) often
comprise multi-functional compounds which may act as a
cross-linking agent and/or as a grafting agent. These polymers are
usually prepared in several stages.
[0044] Olefin-containing copolymers such as olefin acrylates and
olefin diene terpolymers can also be used as impact modifiers in
the present compositions. An example of an olefin acrylate
copolymer impact modifier is ethylene ethylacrylate. Other higher
olefin monomers can be employed in copolymers with alkyl acrylates,
for example, propylene and n-butyl acrylate. The olefin diene
terpolymers are well known in the art and generally fall into the
EPDM (ethylene propylene diene) family of terpolymers. Polyolefins
such as polyethylene, especially low density polyethylene (LDPE),
and polyethylene copolymers with alpha olefins are also of use in
these compositions.
[0045] Polyolefin copolymers with gylcidyl acrylates or
methacrylates may be especially effective in the impact
modification of polyester containing blends. Terpolymers of
ethylene with alkyl acrylates or methacrylates and glycidyl
methacrylates may be especially preferred.
[0046] Styrene-containing polymers can also be used as impact
modifiers. Examples of such polymers are
acrylonitrile-butadiene-styrene (ABS),
acrylonitrile-butadiene-alpha-methylstyrene, styrene-butadiene,
styrene- butadiene-styrene (SBS), styrene-ethylene butylene-styrene
(SEBS), methacrylate-butadiene-styrene (MBS), and other high impact
styrene-containing polymers.
[0047] The polyolefin or SEBS rubbers can be further modified by
reaction with maleic anhydride, itaconic anhydride and related
unsaturated carboxylic acid anhydrides to give anhydride grafted
rubbers.
[0048] Most preferred rubbery impact modifiers are MBS, SEBS and
SEBS maleic anhydride grafted rubbers.
[0049] Additionally, it may be desired to employ inorganic fillers
to the thermoplastic resin provided the favorable properties are
not deleteriously effected. Typical inorganic fillers include:
alumina, amorphous silica, anhydrous alumino silicates, mica,
wollastonite, clays, talc, metal oxides such as titanium dioxide,
zinc sulfide, ground quartz, and the like. Low levels (0.1-10.0 wt.
%) of very small particle size (largest particles less than 10
microns in diameter) are preferred.
[0050] The composition of the present invention may include
additional components which do not interfere with the previously
mentioned desirable properties but enhance other favorable
properties such as antioxidants, lubricants, mold release
materials, colorants, nucleants or ultra violet (UV)
stabilizers.
[0051] Flame-retardant additives are desirably present in an amount
at least sufficient to reduce the flammability of the polyester
resin, preferably to a UL94 V-0 rating. The amount will vary with
the nature of the resin and with the efficiency of the additive. In
general, however, the amount of additive will be from 2 to 30
percent by weight based on the weight of resin. A preferred range
will be from about 15 to 20 percent.
[0052] Typically halogenated aromatic flame-retardants include
tetrabromobisphenol A polycarbonate oligomer, polybromophenyl
ether, brominated polystyrene, brominated BPA polyepoxide,
brominated imides, brominated polycarbonate, poly (haloaryl
acrylate), poly (haloaryl methacrylate), or mixtures thereof.
[0053] Examples of other suitable flame retardants are brominated
polystyrenes such as polydibromostyrene and polytribromostyrene,
decabromobiphenyl ethane, tetrabromobiphenyl, brominated alpha
omega-alkylene-bis-phthalimides, e.g.
N,N'-ethylene-bis-tetrabromophthali- mide, oligomeric brominated
carbonates, especially carbonates derived from tetrabromobisphenol
A, which, if desired, are end-capped with phenoxy radicals, or with
brominated phenoxy radicals, or brominated epoxy resins.
[0054] The flame retardants are typically used with a synergist,
particularily inorganic antimony compounds. Such compounds are
widely available or can be made in known ways. Typical, inorganic
synergist compounds include Sb.sub.2O.sub.5, SbS.sub.3, sodium
antimonate and the like. Especially preferred is antimony trioxide
(Sb.sub.2O.sub.3). Synergists such as antimony oxides, are
typically used at about 0.5 to 15 by weight based on the weight
percent of resin in the final composition.
[0055] Also, the final composition may contain
polytetrafluoroethylene (PTFE) type resins or copolymers used to
reduce dripping in flame retardant thermoplastics.
[0056] The blends of this invention can be processed by various
techniques including injection molding, blow molding, extrusion
into sheet, film or profiles, compression molding and etc. They can
also be formed into a variety of articles for use in, for example;
electrical connectors, electrical devices, computers, building and
construction, outdoor equipment, trucks and automobiles.
EXAMPLES
[0057] The following examples illustrate the present invention, but
are not meant to be limitations to the scope thereof. The examples
of Tables 1-6 where all prepared and tested in a similar
manner:
[0058] All ingredients of the blend where tumbled together for 1-5
min. at room temperature and fed into a 30 mm twin screw extruder
where they were melted and mixed at 520.degree. F.; 300 rpm using
vacuum venting All ingredients were throat fed. The compounded
strands where cooled in a water bath, blown dry with air and
chopped into pellets. Samples where dried for 4h at 190.degree. F.
in a dehumidifying hopper dryer prior to injection molding.
[0059] Samples were injection molded on an 85 ton molding machine
using the following conditions: barrel temperature, 510.degree. F.;
mold temperature, 150.degree. F.; cycle time, 37 sec. Samples where
immediately paced in a sealed foil bag and where tested from the
bags after a few days cooling.
[0060] Tensile elongation at break was tested on 7.times.1/8 in.
injection molded bars with a crosshead speed of 2 in./min. using
ASTM method D648.
[0061] Melt Viscosity (MV) was measured at 250.degree. C. or 266 C.
using a Tinius Olsen model UE-4-78 rheometer, a weight of 21,6000
g, and an orifice with a 0.042 inch diameter. Samples where dried 1
h at 150.degree. C. prior to testing.
[0062] Polyester sodium sulfonate ionomer resins where made by melt
reaction of dimethyl terephthalate (DMT), butane diol and sodium
sulfo dimethyl isophthalate. The sodium sulfo isophthalate was used
at 3 or 5 mole % based on DMT content. The blend was heated with
100-200 ppm titanium octyl titanate catalyst under vacuum until the
desired viscosity was achieved. The reaction was cooled and the
resin isolated and granulated for compounding and blending.
Examples 1-3
[0063] Table 1 shows a series of PBT Ionomer resins with 5 mole %
sodium sulfo isophthalate units blended with 30 to 70 wt % Nylon
6,6. As can be seen comparing the examples to the controls with no
ERL epoxide; 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane
carboxylate (ERL4221 from Union Carbide Co.), elongation at beak
and melt viscosity are increased in most cases. Blends with higher
nylon content tend to show more improvement.
[0064] Examples 1-3 all show good appearance with no
pearlescence.
1 TABLE 1 Control Exp. Invention Exp. A B C 1 2 3 PBT I-5% 69.85
49.85 29.85 28.65 48.65 68.65 PA 6,6 30 50 70 70 50 30 ERL 0 0 0
1.1 1.1 1.1 NaSt 0 0 0 0.1 0.1 0.1 I-1076 0.15 0.15 0.15 0.15 0.15
0.15 MV @ 266 oC 1988 2012 2969 5638 3671 2620 % Elong. 4 4 6 19 10
5 IRGANOX 1076 is a hindered phenol ester antioxidant from Ciba
Geigy Co. NaSt is sodium stearate
Examples 4-6
[0065] As shown in Table 2 the 5 mole % PBT ionomer resin of the
previous examples with Nylon 6 shows superior elongation with the
addition of epoxide. In this case, as in Table 1, sodium stearate
(NaSt) was added as a catalyst. Again higher level of nylon favor
improved elongation and higher MV. The examples 4-6 showed no
pearlescence and good appearance.
2 TABLE 2 Control Exp. Invention Exp. D E F 4 5 6 PBT I-5% 69.85
49.85 29.85 28.65 48.65 68.65 PA 6 30 50 70 70 50 30 ERL 0 0 0 1.1
1.1 1.1 NaSt 0 0 0 0.1 0.1 0.1 I-1076 0.15 0.15 0.15 0.15 0.15 0.15
MV @ 250 oC 7958 11804 18206 16884 15240 12077 % Elong. 16 7 22 162
16 13
Example 7
[0066] In Table 3 a PBT ionomer with only 1 mole % sodium sulfo
isophthalate units is blended with nylon 6,6 with and without ERL
epoxide. Even with only 1 mole % sodium sulfo isophthalate in the
ionomer improved elongation and good appearance is observed.
3 TABLE 3 Control Invention Exp. Exp. G 7 PBT I-1% 49.7 49.2 PA 6,6
50 50 ERL 0 0.5 PEPQ 0.15 0.15 I-1076 0.15 0.15 % Elong. 15 20
PEP-Q is an aryl phosphonite stabilizer from Clariant Co.
Examples 8-10
[0067] Table 4 shows a series of blends where a 3% sodium sulfo
isophthalate PBT of MV 1200-1600 posie @250.degree. C. is blended
with nylon 6,6, a Methyl methacrylate Butadiene Styrene core shell
impact modifier (MBS EXL2691 from the Rohm & Hass Co.) and a
standard polybutylene terephthalate homopolymer (PBT) of 700 posie
MV @250.degree. C. Note how the presence of both the ionomer resin
and epoxide enhance tensile elongation: Exp. 8, 9 and 10.
Appearance is significantly improved over control experiment I
having no polyester sulfonate resin.
4 TABLE 4 Control Experiments Invention Experiments H I 8 9 10
PBTI-3% Low 18 0 35.02 25.2 18 PBT 195 18 35.02 0 10.8 18 PA 66
53.3 54 54 53.02 53.02 MBS 10 10 10 10 10 ERL 0 0.98 0.98 0.98 0.98
Tensile Elong. % 5.6 5.7 10.1 17.66 34.3
Examples 11-19
[0068] Table 5 shows further examples of a 3% PBT ionomer resin
with MBS, ERL epoxide and Nylon 6,6, Nylon 6 or blends of both
polyamides. All examples show good elongation and appearance. In
examples 14-19 a high viscosity PBT (VALOX.RTM. 315 from GE
Plastics, of 8000 posie @250.degree. C., PBT) is blended with the
3% sodium sulfo isophthalate PBT ionomer resin mixture.
5 TABLE 5 Invention Experiments 11 12 13 14 15 16 17 18 19 PBTI-3%
35.0 35.0 35.02 24.22 24.22 24.22 17.02 17.02 17.02 High 2 2 PBT
315 0 0 0 10.8 10.8 10.8 18 18 18 PA 66 54 45 36 54 45 36 54 45 36
PA 6 0 9 18 0 9 18 0 9 18 MBS 10 10 10 10 10 10 10 10 10 ERL 0.98
0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 Tensile 25.3 22.9 23.3 90.2
28.4 85.1 50.8 33.2 161.8 Elong. % PBTI-3% MV = 8000 to 10000 High
poise @ 250.degree. C.
Example 20
[0069] Table 6 shows a blend of 3% PBT sodium sulfo isophthalate
with a low viscosity 700 posie standard PBT, Nylon 6,6 and a
mixture of two types of SEBS (Styrene-Ethylene Butylene-Styrene)
block copolymer sold by Shell Co. as KRATON.RTM. G1651 and
1901.times. FG). The 1901.times. rubber is modified with a low
level of grafted maleic anhydride, the G1651 is an unfunctionalized
SEBS rubber. Various additive are also present: PETS is
pentaerythritol tetra stearate, a mold release, IRGANOX.RTM. 1098
is a hinderd phenol amide antioxidant from Ciba Geigy Co,
SEENOX.RTM. 412 is a tetra functional thio-ester antioxidant from
Ferro Co. and PEP-Q.RTM. is a bis phosphonite stabilizer sold by
Clariant Co. Note how the added ERL epoxide improves
elongation.
6 TABLE 6 Control Exp. Invention Exp. J 20 PBT I-3% Low 17 17 PBT
195 17 17 PA 66 53.3 52.3 Kraton FG 1901X 2 2 Kraton G 1651 10 10
ERL 0 1 PETS (mold release) 0.2 0.2 Irganox 1098 0.2 0.2 Seenox
412S 0.2 0.2 PEP-Q 0.1 0.1 Tensile Elong. % 6.3 15.6
* * * * *