Molding resins based on blends of acid copolymer/hydrocarbon polyolefin/reinforcing fiber/wetting agent

Blends of hydrocarbon polyolefin, reinforcing fiber, acid copolymer of .alpha.-olefin and .alpha.,.beta.-ethylenically unsaturated carboxylic acid and wetting agent are provided wherein the acid copolymer has from 0 to about 90 percent of the acid groups ionized by neutralization with metal ions. Such blends have excellent Izod impact values and fast molding cycles and as such are particularly suitable as molding resins.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to molding resins and more specifically it relates 
to molding resins based on acid copolymer/hydrocarbon 
polyolefin/reinforcing fiber blends modified by the addition of wetting 
agents. 
2. Description of the Prior Art 
U.S. Pat. No. 3,639,331, "Glass Fiber Reinforced Resins Containing 
Dispersion Aid" discloses improved glass dispersibility in a thermoplastic 
resin at glass concentrations ranging from 20-90 weight % using as the 
dispersing aid a hydrocarbon lubricant, or a plasticizer or a low 
molecular weight resin at concentrations ranging from 0.5 to 8.0 weight %. 
This patent primarily refers to low molecular weight oils and plasticizer 
as dispersing aids using an 80% by weight glass concentrate and blending 
this with unreinforced polymer to give a final product having 20% glass 
fiber content. This two step blending process shows no significant 
improvement in physical properties. 
U.S. Pat. No. 3,640,943, "Polymer-Filler Composition", discloses a 
composition comprising a base polymer, a filler and a surface-active 
additive which is a block copolymer (polydiphenyl 
siloxane-polydimethylsiloxane). The block copolymer additive contains at 
least two polymerized comonomers, one of which is compatible with the base 
polymer thereby imparting stability to the composition and the second of 
which is surface active in the composition so that the block copolymer is 
concentrated at the interface between the filler and base polymer to 
provide a bond therebetween. Although this patent claims improved 
stiffness and greater dimensional stability, other physical properties 
were not significantly improved. 
In neither one of the above patents is there any disclosure of blends based 
on ionomers nor of the use of simple wetting agents to give improved 
physical properties at high filler loadings in hydrophobic polymer 
systems. 
U.S. Pat. No. 3,856,724 discloses reinforced thermoplastic compositions 
based upon a reinforcing agent such as glass fiber or alpha cellulose with 
a polyolefin such as polyethylene, polypropylene, polyisobutylene, etc. 
and a minor amount of an ionic hydrocarbon copolymer, such as an 
ethylene-methacrylic acid copolymer which has been reacted with an 
ionizable metal compound. It is disclosed that generally, the amount of 
the ionic hydrocarbon copolymer will be from about 0.05 to about 35 
percent by weight and, preferably, from about 1 to about 30 percent by 
weight based on the weight of the reinforced thermoplastic composition. 
Copending patent application Ser. No. 236,718 filed Feb. 23, 1981, now U.S. 
Pat. No. 4,387,188 (Attorney Docket No. AD-5095) discloses compositions of 
about 38 to 90% by weight of acid copolymer (from 0 to about 90% 
neutralized), about 5-60% by weight of linear polymer of .alpha.-olefin 
and about 2-50% by weight of reinforcing fiber. 
SUMMARY OF THE INVENTION 
According to the present invention, there is provided a composition 
consisting essentially of 
(a) from about 5 to about 85 percent by weight of acid copolymer selected 
from the group consisting of direct copolymers and graft copolymers 
wherein, 
(A) said direct copolymer is the copolymer of .alpha.-olefin having the 
formula R--CH.dbd.CH.sub.2, where R is a radical selected from the class 
consisting of hydrogen and alkyl radicals having from 1 to 8 carbon atoms 
and .alpha.,.beta.-ethylenically unsaturated carboxylic acids having from 
3 to 8 carbon atoms, the acid moieties being randomly or nonrandomly 
distributed in the polymer chain, 
(1) the .alpha.-olefin content of the copolymer being at least 25 weight 
percent, based on the .alpha.-olefin-acid copolymer, 
(2) the unsaturated carboxylic acid content of the copolymer being from 
about 0.5 to about 50 weight percent, based on the .alpha.-olefin-acid 
copolymer, and 
(3) any other monomer component optionally copolymerized in said copolymer 
being monoethylenically unsaturated, and 
(B) said graft copolymer is obtained by grafting 0.1 to 5 percent by weight 
of .alpha.,.beta.-unsaturated carboxylic acid having 3 to 8 carbon atoms 
or an unsaturated carboxylic acid anhydride onto a preformed polyolefin 
backbone derived from ethylene or ethylene and C.sub.3 to C.sub.8 
.alpha.-olefin, in which polyolefin backbone any other optionally 
copolymerized monomer component is monoethylenically unsaturated, 
said direct or graft acid copolymers having from 0 to about 90 percent of 
the carboxylic acid groups ionized by neutralization with metal ions, said 
ionic copolymers having solid state properties characteristic of 
crosslinked polymers and melt-fabricability properties characteristic of 
uncrosslinked thermoplastic polymers, 
(b) from about 10 to about 90 percent by weight of at least one hydrocarbon 
polyolefin selected from the group consisting of linear polymer of 
.alpha.-olefin having the formula R-CH.dbd.CH.sub.2, where R is a radical 
selected from the class consisting of hydrogen and alkyl radicals having 
from 1 to 8 carbon atoms; copolymer of ethylene and propylene where the 
ethylene content is up to about 20% by weight; linear copolymer of 
ethylene with at least one .alpha.-olefin comonomer having from four to 
ten carbon atoms, where the .alpha.-olefin comonomer content is from about 
2 to about 25 percent by weight; and low density branched homopolymer of 
ethylene; 
(c) from about 5 to about 50 percent by weight of at least one reinforcing 
fiber selected from the group consisting of glass fiber, natural mineral 
fiber, man made mineral fiber and high modulus organic fiber; and 
(d) from about 0.05 to about 5.0 percent by weight of at least one wetting 
agent selected from the group consisting of alkanol amides; betaine 
derivatives; block copolymers comprising a series of condensates of 
ethylene oxide with hydrophobic bases formed by condensing propylene oxide 
with propylene glycol; ethoxylated compounds comprising alcohols, alkyl 
phenols, amines and amides; sulfonated derivatives comprising alkyl 
sulfonates, aryl sulfonates, alkyl-aryl sulfonates, amine and amide 
sulfonates, olefin sulfonates, sulfosuccinates, sulfonated fatty acid 
esters, sulfonates of ethyoxylated alkyl phenols and of oils and of fatty 
acids, naphthalene and alkyl naphthalene sulfonates, condensed naphthalene 
sulfonates, naphthalene and alkyl naphthalene sulfonates and petroleum 
sulfonates, and dodecyl and tridecyl benzene sulfonates; dodecyl and 
tridecyl sulfonic acids; sulfates of alcohols, of ethoxylated alcohols, of 
ethoxylated alkyl phenols, of oils, of fatty acids, of fatty esters, 
alkaryl sulfates, and sodium, ammonium and amine salts of alcohol 
sulfates; phosphate derivatives comprising phosphate esters, phosphate 
alcohol ethoxylates, phosphate ether ethoxylates, phosphate alkyl acids 
and phosphate alkyl quaternaries; quaternary surfactants; and liquid 
polyesters. 
As used herein, the term "consisting essentially of" means that the named 
ingredients are essential; however, other ingredients which do not prevent 
the advantages of the present invention from being realized can also be 
included. 
DETAILED DESCRIPTION OF THE INVENTION 
Surprisingly, it was found that relatively small amounts of wetting agents 
enable substantial amounts of reinforcing agents to be readily 
incorporated into ionomer blends. The toughness and flexibility of these 
compositions are significantly improved over compositions without 
surfactant. 
Acid copolymers suitable for the present invention are selected from the 
group consisting of direct copolymers and graft copolymers wherein (A) 
said direct copolymer is the copolymer of .alpha.-olefin having the 
formula R--CH.dbd.CH.sub.2, where R is a radical selected from the class 
consisting of hydrogen and alkyl radicals having from 1 to 8 carbon atoms, 
and .alpha.,.beta.-ethylenically unsaturated carboxylic acid having from 3 
to 8 carbon atoms, the acid moieties being randomly or nonrandomly 
distributed in the polymer chain, (1) the .alpha.-olefin content of the 
copolymer being at least 25 weight percent, based on the 
.alpha.-olefin-acid copolymer, (2) the unsaturated carboxylic acid content 
of the copolymer being from about 0.5 to about 50 weight percent, based on 
the .alpha.-olefin-acid copolymer, and (3) any other monomer component 
optionally copolymerized in said copolymer being monoethylenically 
unsaturated, and (B) said graft copolymer being obtained by grafting 0.1 
to 5 percent by weight of .alpha.,.beta.-unsaturated carboxylic acid 
having 3 to 8 carbon atoms or an unsaturated carboxylic acid anhydride 
onto a preformed polyolefin backbone derived from ethylene or ethylene and 
C.sub.3 to C.sub.8 .alpha.-olefin, in which polyolefin backbone any other 
optionally copolymerized monomer component is monoethylenically 
unsaturated, said direct or graft acid copolymers having from 0 to about 
99% of the carboxylic acid groups ionized by neutralization with metal 
ions, said ionic copolymers having solid state properties characteristic 
of crosslinked polymers and melt fabricability properties characteristic 
of uncrosslinked thermoplastic polymers. The acid copolymers are further 
described in U.S. Pat. Nos. 4,351,931; 4,026,967; 4,252,924; and 
4,248,990. The ionic copolymers are described in U.S. Pat. No. 3,264,272. 
Acid copolymers can also be derived by reacting .alpha.-olefin polymers 
with unsaturated acids. Hence, polyolefins or olefin copolymers can be 
reacted with .alpha.,.beta.-unsaturated acids either thermally or by using 
a peroxide catalyst to give acid functionalized graft copolymers. These 
polymers can be used in place of or in conjunction with the directly 
copolymerized acid copolymers or they can be partially neutralized to give 
materials which can be used in place of or in conjunction with the 
directly copolymerized acid copolymers or their ionomers. 
The acid copolymers generally are present in the amount of from about 5 to 
about 85 percent by weight in the reinforced compositions of the present 
invention. Preferably the acid copolymer is present in the amount of from 
about 20 to about 60 percent and most preferably from about 25 to about 55 
weight percent. 
Higher levels of acid copolymers are preferred because they result in 
greater resistance to Gardner impact and improved room temperature Izod 
impact strength. 
Preferably the .alpha.,.beta.-ethylenically unsaturated acid is acrylic 
acid or methacrylic acid and most preferably it is methacrylic acid. The 
ionic copolymer is preferably neutralized to the extent of from about 5 to 
about 80 percent and most preferably from about 15 to about 75 percent. 
The .alpha.-olefin content of the copolymer is preferably at least about 
70 weight percent, based on the .alpha.-olefin-acid copolymer and most 
preferably it is at least about 88 weight percent. The unsaturated 
carboxylic acid content of the copolymer is preferably from about 3 to 
about 30 weight percent and most preferably from about 3 to about 12 
weight percent, based on the .alpha.-olefin-acid copolymer. 
The metal ions are preferably selected from the group consisting of sodium, 
potassium, calcium, magnesium, zinc and strontium, and most preferably the 
metal ion is zinc. 
The hydrocarbon polyolefin suitable in the blends of the present invention 
is selected from the group consisting of linear polymer of .alpha.-olefin 
having the formula R--CH.dbd.CH.sub.2, where R is a radical selected from 
the class consisting of hydrogen and alkyl radicals having from 1 to 8 
carbon atoms; copolymer of ethylene and propylene where the ethylene 
content is up to about 20% by weight; linear copolymer of ethylene with at 
least one .alpha.-olefin comonomer having from 4 to 10 carbon atoms, where 
the .alpha.-olefin comonomer content is from about 2 to about 25 percent 
by weight; and low density branched homopolymer of ethylene. Preferably 
the linear polyolefin is selected from the group consisting of 
polyethylene, polypropylene, polybutene-1, poly-4-methyl pentene-1, and 
copolymers thereof and most preferably the linear polyolefin is 
polyethylene. 
When polyethylene is the linear polyolefin in the blends of the present 
invention, it has generally a density of from about 0.91-0.97, preferably 
from about 0.935 to about 0.970 and most preferably from about 0.95 to 
0.97. The melt index (MI) of the linear polyethylene is generally from 
about 0.1 to about 100, preferably from about 0.2 to about 5 and most 
preferably from about 0.3 to about 3. Linear homopolymers of ethylene, 
such as a 3 MI narrow molecular weight distribution resin, appear to give 
adequate toughness and heat deflection temperatures. However, if higher 
toughness is needed, a medium molecular weight distribution homopolymer 
with a 0.45 melt index can be used. Such materials will reduce the melt 
flow of the final blend. 
Generally, from about 10 to about 90 percent by weight of linear polyolefin 
is used in the blends of the present invention. Preferably the amount is 
from about 20 to about 55 percent by weight. 
The third essential ingredient of the blends of the present invention is 
the reinforcing fiber which can be selected from the group consisting of 
glass fibers, natural mineral fibers, man-made, manufactured mineral 
fibers (e.g., graphite, aluminum oxide, etc.), and high modulus organic 
fibers. The reinforcing fibers generally used in thermoplastic materials 
are subjected to shearing during extrusion and molding, hence their 
lengths and aspect ratios are reduced. Glass fibers usually range from 
0.001 to 0.030 inches in length after compounding, and minerals are 
usually shorter. Any compounding system which does not lower the lengths 
or aspect ratios to this degree should give improved stiffness properties 
in the final composite materials. Before compounding, the reinforcing 
fibers have an L/D aspect ratio of from about 10 to about 1500. 
The type of glass or mineral fiber employed does not appear to be critical. 
However, fibers with high L/D ratios appear to give higher heat deflection 
temperatures. Commercial glass fibers sold as reinforcing agents for 
thermoplastics are useful for this application and appear to give better 
properties than the shorter mineral fibers. 
Owens-Corning's fiber glass comes with various types of coatings. Their 
available products have sizing denoted by the following numbers and are 
recommended for the listed thermoplastics. 
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Sizing Recommended for Thermoplastics 
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409 Polycarbonate and Acetal 
411 Nylon 
414 ABS and SAN 
415 HDPE and Polycarbonate 
418 In Polycarbonate at Low Loadings 
419 Thermoplastic Polyester and Nylon 
452 Polypropylene 
497 Polyphenylene Oxide 
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Glass OCF-415AA or OCF-415BB and OCF-419AA appear to give the best 
combination of tensile properties, toughness and heat deflection 
temperature. 
A similar glass from Pittsburgh Plate Glass, PPG-3450, gave good results. 
The preferred reinforcing fibers are glass fibers and mineral fibers having 
an L/D aspect ratio of from about 20 to about 1000, and most preferably of 
from about 100 to about 400. 
Generally, the amount of the reinforcing fiber is from about 5 to about 50 
percent by weight. Preferably the fiber should be present in from about 10 
to about 35 percent by weight and most preferably from about 12 to about 
25 percent by weight. 
The fourth essential ingredient of the blend is a wetting agent. For the 
purposes of the present invention, a wetting agent is a material which 
when added in low concentration modifies the surface tension between the 
fibrous reinforcement and the polymer component. Surfactants, as generally 
classified in McCutcheon's "Emulsifiers and Detergents--North American 
Edition--1981" are one well known class of wetting agents. Surfactants 
which are effective in attaining the purposes of this invention are those 
which are selected from the group consisting of alkanol amides; betaine 
derivatives; block copolymers comprising a series of condensates of 
ethylene oxide with hydrophobic bases formed by condensing propylene oxide 
with propylene glycol; ethoxylated compounds comprising alcohols, alkyl 
phenols, amines and amides; sulfonated derivatives comprising alkyl 
sulfonates, aryl sulfonates, alkyl-aryl sulfonates, amine and amide 
sulfonates, olefin sulfonates, sulfosuccinates, sulfonated fatty acid 
esters, sulfonates of ethoxylated alkyl phenols and of oils and of fatty 
acids, naphthalene and alkyl naphthalene sulfonates, condensed naphthalene 
sulfonates, naphthalene and alkyl naphthalene sulfonates and petroleum 
sulfonates, and dodecyl and tridecyl benzene sulfonates; dodecyl and 
tridecyl sulfonic acids; sulfates of alcohols, of ethoxylated alcohols, of 
ethoxylated alkyl phenols, of oils, of fatty acids, of fatty esters, 
alkaryl sulfates, and sodium, ammonium and amine salts of alcohol 
sulfates; phosphate derivatives comprising phosphate esters, phosphate 
alcohol ethoxylates, phosphate ether ethoxylates, phosphate alkyl acids 
and phosphate alkyl quaternaries; quaternary surfactants. 
The number of surfactants in existence is enormous; the examples named 
above can be replaced by other close analogs with good results and without 
departing from the spirit of this invention. 
The preferred surface active agents are selected from the group consisting 
of alkanol amides; betaine derivatives; block copolymers consisting 
essentially of a series of condensates of ethylene oxide with hydrophobic 
bases formed by condensing propylene oxide with propylene glycol; 
ethoxylated compounds consisting essentially of ethoxylated alcohols, 
alkyl phenols, amines and amides; sulfonated derivatives consisting 
essentially of alkyl sulfonates, alkyl-aryl sulfonates, amine and amide 
sulfonates, sulfonated fatty acid esters, sulfonates of ethoxylated alkyl 
phenols and of oils and of fatty acids, naphthalene and alkyl naphthalene 
sulfonates, and condensed naphthalene sulfonates and dodecyl and tridecyl 
benzene sulfonates; sulfates of alcohols, of ethoxylated alcohols, of 
fatty acids, alkaryl sulfates, and sodium, ammonium and amine salts 
thereof; phosphate derivatives consisting essentially of phosphate esters, 
phosphate alcohol ethoxylates, phosphate ether ethoxylates, phosphate 
alkyl acids and phosphate alkyl quaternaries; quaternary surfactants. 
The most preferred surfactants are selected from the group consisting of 
alkyl sulfonates, alkyl-aryl sulfonates, amine and amide sulfonates, 
sulfonated fatty acid esters, sulfonates of ethoxylated alkyl phenyls and 
of oils and of fatty acids, naphthalene and alkyl naphthalene sulfonates, 
and condensed naphthalene sulfonates; sulfates of alcohols, of ethoxylated 
alcohols, of fatty acids, alkaryl sulfates, and sodium, ammonium and amine 
salts of alcohol sulfates; phosphate esters. 
In using surface active agents in the compositions of this invention, the 
amount is from about 0.05% to about 5% by weight, and preferably from 
about 0.1 to about 2.5%. 
In many cases, for the user's convenience, the surfactant may be offered as 
a solution or dispersion in water or in an organic solvent. In such cases, 
the percentages in the preceding paragraph refer to the amount of active 
ingredient present--and not to the product as supplied. 
Liquid polyesters are a second class of wetting agents useful in the 
practice of this invention. These materials are, in general, condensation 
products of polybasic acids and polyols. The term "liquid" in the context 
of the present invention is used to mean pourable at room temperture. The 
acid component is most often a saturated aliphatic dibasic acid or an 
aromatic dibasic acid; adipic acid, azelaic acid, phthalic acid, sebacic 
acid, and glutaric acid, or mixtures of these acids are commonly used. The 
polyol can be an aliphatic polyol or a poly oxyalkylene polyol, such as 
ethylene glycol, propylene gycol, 1,4- and 1,3-butane glycol, diethylene 
glycol, and polyethylene glycol. Preferred polyester compositions would 
consist of an acid component of which greater than 50% by weight are 
aliphatic dibasic acids, and a polyol component of aliphatic polyol or 
even more preferably aliphatic glycol. Most preferred compositions are 
based on adipic or azelaic acid, and propylene glycol or the 1,3- or 
1,4-butane glycol. The molecular weight of these plasticizers can vary 
from a low of a few hundred up to a high of about 10,000. The molecular 
weight of commercial products is seldom specified; however, typically in 
the trade, the molecular weight range of the product is classified as low, 
medium or high. The preferred range for purposes of this invention is that 
classified as medium. 
In addition to the required components, it is customary to add small 
amounts of pigments or fillers or blowing agents to the other ingredients 
of the blend. These materials, along with mold release agents and 
lubricants, can be added to the polymer blend in amounts that are normally 
used without adversely affecting the physical properties of the blend. 
In copending application Ser. No. 236,718, it was shown that blends of acid 
copolymer, linear polyolefin and reinforcing fiber having superior 
physical properties can be prepared without the use of a surfactant. 
However, such superior properties can only be achieved in an apparatus 
such as a twin screw extruder which results in extremely high shear 
forces. In older mixing devices such as single screw extruders which 
cannot be operated at sufficiently high shear rates, it was found that 
toughness was erratic and generally lower than desired. In addition, when 
subjected to repeated flexing, sheets made from the blends containing acid 
copolymer or lower ionomerized levels of acid copolymers without 
surfactants broke easily. 
The following examples serve to illustrate the present invention. All parts 
and percentages are by weight unless otherwise specified. As with most 
thermoplastic compositions, it is desired to achieve an optimum balance of 
properties. On occasion, the achievement of high toughness can result in 
reduction of flexural modulus or heat deflection temperature. Thus, in any 
particular application, the choice of ingredients will be determind by the 
balance of properties desired. 
PREATION OF BLENDS 
All of the surfactants evaluated were dissolved in small quantities of 
isopropyl alcohol (about 100 grams) and manually dispersed on the 
reinforcing fibers or on the entire composite blend in a large 
polyethylene bag. The bag was filled with air and manually shaken for 1-2 
minutes. The alcohol was allowed to evaporate in a laboratory hood 
overnight prior to either blending as described above (if 
surfactant/alcohol solution was applied only to the reinforcing fiber) or 
extrusion. The blends of Examples 1 through 29, as well as the blends of 
the Comparative Examples, were extruded on a Sterling 2" single screw 
extruder using a 10B screw with a single hole die. Example 30, because of 
its high glass content, could not be processed on the single screw 
extruder. This formulation was processed on a 28 mm W&P twin screw 
extruder at the same temperature using a two-hole die. The screw 
configuration used was designed to give the minimum amount of shear. The 
extruded strand was quenched (cooled) in a water trough and pelletized 
through a Cumberland, Size 6 Cutter. 
PREATION OF TEST PIECES 
All test pieces as specified by the various ASTM tests were made on a Van 
Dorn 6-ounce C Injection Molding Machine at temperatures ranging from 
210.degree. to 225.degree. C. with an injection pressure of 1100 psi. The 
injection and hold cycle times were both 20 seconds. 
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Test Procedures 
Test ASTM Method 
Notched Izod D-256 
Tensile Impact D-18225 
Flex Modulus D-790 
Gardner Impact D-3029-72 
180.degree. Flex Bend Test* 
-- 
Elongation, Break % D-638 
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*This is a subjective test in which a 3" .times. 5" .times. 0.125" 
injection molded plaque is bent in one direction at 180.degree. and then 
is bent in the opposite direction at 180.degree.. This constitutes one 
full cycle. After each cycle, the plaque is observed for breaking or 
cracking.