JPS59529B2 - Method for improving properties of compositions containing ungrafted crystalline polypropylene - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for improving the properties (including crystallization rate) of compositions containing ungrafted crystalline polypropylene.

Polymers, particularly polyolefins, modified by graft polymerization with about 0.1 to 15% by weight of mono- or polycarboxylic unsaturated carboxylic acid monomers or derivatives thereof to unmodified polyolefins.
When added at a concentration of , it imparts significant advantages to the properties of the unmodified polyolefin.

Grafting of acrylic acid and glycidyl acrylate is particularly noteworthy for these purposes. The unmodified polyolefin may be of a type with or without fillers added. The present invention is applicable to various types of polyolefins.

A. Nucleated varieties The crystalline polymers exiting the reactor have high tensile strength and great hardness in their normal form, but at the same time they lack transparency or sharpness and, in the case of fairly thick articles, become opaque or translucent, forming thin films. In this case, clouding occurs.

Highly crystalline polypropylene also has relatively low impact resistance, especially at low temperatures.

It is known that adding nucleating agents to the polymer greatly reduces the opacity and haze problems.

This obviously modifies the crystallization process and in particular changes the size of the spherulites formed during crystallization. Certain nucleating agents reduce crystallization time and warpage to some extent. Most nucleating agents result in increased mold shrinkage, which is undesirable in most cases. Known nucleating agents are finely divided solid inorganic materials such as silica, or organic fatty or polycarboxylic acids and their derivatives. All of these are relatively difficult to mix into the base polypropylene. See U.S. Patent Nos. 2,991,264, 3,517,086, and 3,207,735-739.

B. Filled molding varieties A wide variety of materials are used in polyolefins as fillers and reinforcements.

These typically include inorganic materials such as glass fiber, asbestos, mica, and the like. "Modern Plastics Dictionary"
edia), 1970-71, pages 330-368, such materials are extensively disclosed. In contrast to transparency, which is often required in nucleated varieties, this property is not required in filled molded varieties.

Nevertheless, the latter varieties possess one or more of the following properties to an even greater extent than other varieties: good impact resistance, high tensile strength, good secant flexural modulus, and good thermal deflection. I need. C Impact-resistant varieties These can be added with or without fillers as required.

Usually they have copolymer or elastomer components or both, so transparency is not required. One or more other characteristics mentioned above are often required. Glass fiber is covered by French Patent No. 1,511,863 and British Patent No. 1,094.
, 439, U.S. Patent Nos. 3,579,476 and 3,
No. 437,550 with grafted polyolefins.

In accordance with the present invention, it has been discovered that olefin polymers grafted with certain acids (or derivatives thereof) can be added in relatively small proportions to other polymers, particularly crystalline olefin polymers, to produce novel compositions. It was done. These new compositions exhibit outstanding properties as impact resistant filled nucleated varieties. Such grafted polymers can thus act not only as nucleating agents, but also as modification additives for all purposes, i.e. for all molding varieties, especially impact-resistant and filled varieties. .

The resulting polymer compositions containing such additives require only a substantially shorter time to reach their maximum crystallization rate under isothermal conditions. They crystallize even at relatively high temperatures when cooled from the melt, producing smaller spherulites than comparable unnucleated polypropylene polymers. Other physical properties of crystalline olefin polymers (with or without fillers) modified with additives of this type are impact properties, secant flexural modulus (ASTMD 79O) and tensile strength (ASTMD 638).

For unfilled and non-impact varieties, the clarity of the polymer is considerably improved. Furthermore, the polymer compositions of the present invention produced by combining small amounts of the modifiers described herein with unmodified polymers exhibit substantially less molded warpage than polymers that do not contain the additives of the present invention. show.

They require less molding time. moreover,
They have a greater tendency to shrink in the mold and therefore have better fibrous properties under certain conditions. One of the most important properties that filled polymers have is their resistance to deformation or flow properties under certain loads at elevated temperatures.

The standard method of testing a given polymer property in this regard is the heat deflection point, or more commonly the "heat deflection temperature" (H
DT). ,
This test is fully described in ASTM D648-56 and, simply put, the standard test bar is rated at 66 or 264 ps.
i is to measure the temperature at which it deflects 0.010 inch under any specified load.

Crystalline polyolefins, especially reinforced and filled crystalline polypropylene compounds used in environments where high temperatures are a problem, desirably have relatively high HDT.

These items are used under the 7th door of cars, washing machines,
It is known that the use of fillers (mica) and reinforcements such as glass fibers in the dryer increases the HDT of thermoplastics. In accordance with the present invention, it has been found that small amounts of modifiers in polypropylene compositions increase the heat deflection temperature of both filled and unfilled varieties. but,
More importantly, the present invention shows that glass fiber-reinforced polypropylene containing small amounts of modifiers exhibits heat deflection temperatures that are much higher than the effect of either addition alone, thus exhibiting a significant synergistic phenomenon. There was found.

The modifiers of the present invention further offer several important advantages.

One of the most important of these is in the field of mixing. For example, micronized versions of materials known in the art to act as nucleating agents, such as silica or organic acids, can be used to prepare relatively large particles to be nucleated! It is very difficult to mix with molecular weight polymers. It is desirable that the modifier has essentially the same physical properties as the material to be molded, and therefore can be blended into the material to be molded like any other compatible polymer, and it is achieved by. Furthermore, a class of known nucleating agents based on organic acids are usually difficult to handle and present problems during molding.

Thus, these substances are very often slightly volatile to extremely volatile. Under the high temperatures of molding, they tend to plate out onto the mold, causing fouling and other undesirable contamination of the mold, which is very expensive. In sharp contrast, the additives of the present invention do not have these drawbacks. Sodium benzoate, which has been used commercially as a nucleating agent, must be added as very fine particles to be effective.

It requires an expensive grinding stage. The additives of the present invention are also very advantageous in that they can be used in relatively small amounts, so that the total blend is endowed with considerable economic benefits.

It should also be noted that the spherulite dimensions of the crystallized particles produced from the compositions of the present invention are similar to those found in particles produced in the same manner from the same polymer without the use of modifiers. The clarity of films or even thicker shaped articles made from the nucleated compositions prepared according to the present invention is also substantially improved compared to articles that are not nucleated.

Another advantage of the present invention is that the modifier generally provides better mixing or homogenization of the polymer melt blend.

Thus, the modifiers of the present invention are more easily and more uniformly dispersed than conventional additives, especially conventional nucleating agents. Another advantage of the present invention is that because the novel compositional mixture of the present invention coagulates at a somewhat higher temperature than the same polymers without modifiers, processing can be carried out in a considerably shorter time and the cycle time This means that the processing equipment that has invested a large amount of capital can be used more effectively.

Thus, the benefits of reduced cycle time and reduced warpage are obtained from the nucleation effect of the modifier even when clarity is not a desirable property. As mentioned above, in addition to the clarity problem, one of the disadvantages in the mechanical properties of crystalline polyolefins such as polypropylene is the lack of impact strength, especially at low temperatures.

A number of techniques have corrected this drawback, but perhaps the best known is the addition of flexible polymers, such as rubber-like materials, into crystalline polymers. These rubbery materials include polyisobutylene, polybutadiene, polyethylene-propylene elastomers, and the like.

In addition, the elastomeric and plastic components that make up the binary mixture are flexible and interact with the other two polymers in an unknown manner to create a ternary mixture of good impact strength in various polyethylene and ethylene copolymers. Therefore, it can be denatured. Crystalline polyolefins, such as C2 to C8 α such as polypropylene, polyethylene, etc.
- Although particular emphasis has been placed on olefin polymers, many other crystalline thermoplastics may also benefit from the techniques of the present invention, whether blended with crystalline polyolefins such as polypropylene or used completely separately. receive.

These include nylon (polyamide), polyester, polyacetal, polycarbonate, and the like. A feature of the present invention is that the modifiers of the present invention are equally effective, but to some extent even more effective when nucleated with binary and ternary impact mixtures of crystalline polyolefins, particularly those predominant in polypropylene. be. Ethylene-propylene reactor copolymers also benefit from the addition of the modifiers of this invention. Furthermore, in most cases,
Additives need only be added in very small amounts.

Furthermore, although some improvements in the clarity of binary or ternary blends are obtained by using the additives of the present invention, more important improvements are seen in other properties. As mentioned above, one of the advantages of the present invention is that the mixing can be carried out directly in the extruder, unlike the intensive mixing, e.g. heated rolls and Banbury that was required with prior art nucleating agents such as sodium benzoate. Kneading by a mixer becomes unnecessary. Photomicrographs of modified compositions of the invention containing glass fiber fillers show that the degree of adhesion to glass is much greater than in the absence of graft components.

Clearly, the grafting component, ie acrylic acid or glycidyl acrylate, is interacting with the reinforcement in some way. Also, great emphasis has been placed on the use of relatively small amounts of modifiers, which are believed to be the first novel feature of the invention, but which provide the greatest improvement in certain physical properties (e.g. heat deflection). To achieve this, a considerably large amount of denaturing agent must be used.

Such amounts may be on the order of 15-60%, preferably 20-50%, most preferably 30-50% by weight. Other properties of polypropylene compositions that are improved by relatively large amounts of modifiers are tensile strength and Izod impact strength.

These are often glass-reinforced compositions and are used in applications such as under-hood dishwasher stirrers, gears, etc., which are subject to very harsh conditions. Gardner
er) Except for impact properties, other properties of such compositions (containing relatively large amounts of modifier) are not degraded, but above relatively small levels of modifier there is no improvement in nucleation. I can't do it. It is usually not economically advantageous to use an excess of modifying lice, i.e., greater than 60% by weight, than when the special properties described herein are desired. For purposes of this invention, the term "modifier-" is defined as the specific graft polymer additives discussed in detail herein.

It excludes additives traditionally incorporated into polymers. Special cases often arise where more than the usual amount of modifier is required, such as when using certain pigments.

Some pigments tend to interact with the acid component of the modifier;
nullify its effect. Therefore, in this case larger amounts of modifier must be used to counteract this adverse effect. However, glycidyl acrylate graft modifiers are not subject to inactivation by pigments. Another feature of the present invention is the MFR characteristics of the base polymer that are comparable to the MFR of the graft polymer modifier.

Therefore, both MFRs are preferably relatively high. That is, from 3 to 500, preferably from 5 to 2001, most preferably from 5 to 100. Modifier with relatively high MF
Addition to the base polymer of R is not necessary, but is preferred in some cases, as it produces superior results.

There is another inventive feature of the present invention that is noteworthy.

Thus, preformed metal salts of acid (preferably acrylic acid) grafts are also very effective as nucleating agents. Not only can they be used as nucleating agents, but they can also be used in other end uses for which the modifiers of this invention have been described as being particularly useful. Particularly preferred preformed salts are formed from alkali metals, especially sodium and aluminum. The term "preformed salt" is used to distinguish salts that result from in-situ reactions with functional groups of the graft from salts or ash that remain in either the grafted polymer or the modified polymer.

The amount of grafting substances or components or monomers that can be conveniently added to or grafted onto the base polymer to be used for the modifier typically ranges from 1 to 20% by weight, depending on the grafting system used.

In the case of extruder grafting, the grafting reaction takes place in a very short time and in a relatively confined space while the polymer passes through the extruder. Therefore, generally about 1 to 10
It is advantageous to graft % by weight of the graft polymer onto the backbone polymer without producing an excess amount of homopolymer, such as, for example, a polymer of homocarboxylic acids or acid derivatives. 1 to 40% by weight of homopolymer in the grafting monomer is an acceptable amount without adverse effects.
However, amounts of homopolymer above that limit are not preferred. However, for purposes of this invention, the additive graft polymer, or modifier, generally contains about 0.1 to 15, preferably 2 to 8, and most preferably 4 to 10 weight percent of the graft component.

This graft polymer modification, when used as a nucleating agent and for purposes other than very high tensile strength and high Izod impact strength, generally It is used in amounts of 0.1 to 15, preferably 0.5 to 5, particularly preferably 0.5 to 3 and most preferably 0.5 to 2% by weight.

Thus, the amount of grafted component in the resulting blend is very low.

This is shown as follows. Based on the above considerations, the appropriate amount of modifier to be used can be easily calculated. Graft polymers which suitably act as modifiers such as nucleating agents in the compositions of the invention and methods for their preparation are described in the literature.

For example, U.S. Pat. No. 3,177,269;
, No. 270, No. 3,270,090 and British Patent No. 1
, 217,231 and 679,562. However, the most preferred are those prepared by the method described below. Preferred monomers that are grafted onto the backbone polymer to form the modifiers of the present invention are unsaturated acids containing C3 to ClO, preferably C3 to C3 unsaturated mono- and polycarboxylic acids, preferably containing at least one olefinic unsaturated acid. Contains saturated compounds, acid anhydrides, salts, esters, ethers, amides, nitriles, thio, glycidyl, cyano, hydroxyl glycols, and other substituted derivatives thereof.

Examples of such acids, acid anhydrides and their derivatives are maleic acid, fumaric acid, itacone acrylic acid, glycidyl acrylate, glycidyl methacrylate,
C1-C2O alkyl cyanoacrylate, hydroxyethyl methacrylate, acrylic acid polyether, acrylic anhydride, methacrylic acid, crotonic acid, isocrotonic acid, mesaconic acid, angelic acid, maleic anhydride, itaconic anhydride, citratronic anhydride, acrylonitrilic acid , metatalylonitrile, sodium acrylate, calcium acrylate and magnesium acrylate.

Other monomers that can be used alone or in combination with one or more carboxylic acids or derivatives thereof are C8-C5O vinyl monomers such as monovinyl aromatics, i.e. styrene, styrene chloride, styrene bromide, Contains α-methylstyrene, etc.

Other monomers that can be used are vinyl and allyl esters of C,O-C5O such as vinyl butyrate, vinyl laurate, vinyl acetate, vinyl stearate, vinyl adipate, etc., dibutylbenzene, ethylene dimethacrylate, triallyl phosphite, Monomers having two or more vinyl groups such as diallyl cyanurate and triallyl cyanurate.

Nevertheless, in order to obtain the most significant results, it is preferred that the graft copolymers meet some high specific criteria.

The first is that not only does the graft copolymer contain grafting active functional groups, but the molecular weight of the backbone polymer itself is at least somewhat or significantly reduced, so that it has a lower molecular weight than other components (e.g. fillers) in the overall composition. They will be compatible and will have a stronger synergistic effect on the overall composition. Furthermore, C3 to ClO monocarboxylic acids (and derivatives thereof)
Graft polymers are the most effective. Preferred graft polymers for use in the novel compositions of this invention are characterized in several respects. That is, (1) 1 to 100
0, preferably 10 to 250, most preferably 10 to 100, at least 25%, better 50%, most preferably than the MFR or M of the starting polymer having an MI or MFR of no flow to 50. is 200% higher (measured under the conditions of ASTM test number D-1238-65T).

(2) 0.1 to 15, preferably 2 to 8, most preferably 4 to 1, based on the total weight of the graft copolymer.
Graft comonomer content of 0.

(3) at least 5%, preferably 10%, of the base polymer;
% small dice well. In a particularly preferred embodiment, the present invention provides a C2-C3 α-olefin or its acrylic acid (
or a derivative thereof), and the graft is prepared by a special method.

Polymers of C2 to C8 α-olefins are commonly referred to as polyolefins, and for the purposes of this invention include homopolymers as well as copolymers containing C2 to C8 α-olefins and copolymers with other monomers. Diolefin-containing polymers such as butadiene and isoprene are also suitable.

Polyolefins are most often produced using transition metal (Ziegler) melts, but can also be produced using Phillips catalysis or high pressure processes. Methods for making C2-C8 polyolefins are well known and do not form part of this invention. Examples of suitable polyolefins, including both plastic and elastomeric polymers, are low or high density polyethylene, polypropylene, polybutene-1, poly-3-methylbutene-1, poly-4-methyl-pentene-1, or ethylene-propylene copolymers. copolymers of monoolefins and other olefins (mono- or diolefins) or with vinyl monomers, such as
or copolymers of monoolefins and one or more additional monomers, such as EPDMl ethylene/butylene copolymers, ethylene/vinyl acetate copolymers, ethylene/ethyl acrylate copolymers, propylene/4-methylbenzene-1 copolymers, and the like.

The term "copolymer" includes two or more components and substituted derivatives thereof.

Preferred polyolefins used as base polymers to prepare modifiers include propylene or ethylene or both.

namely polypropylene and polyethylene. The starting polymer used as the base material of the present invention is 1 to 40,
A melt index (M) of preferably 5 to 40, most preferably 15 to 40, or a melt flow rate of about 0.1 to 50, preferably 0.1 to 5.0, most preferably 0.5 to 2. (MFR). In the preparation of normally solid polymers of 1-olefins, certain rheological properties are often utilized for control purposes.

One of these more commonly utilized rheological properties is the melt index or melt flow rate, which characterizes the additivity of a polymer and more closely indicates the molecular weight of the polymer. Polyethylene melt index is usually A. S. T. M-Iken D-1238-65T
Measured according to

In this test, the extrusion rate of the polymer (f per 10 minutes, passing through a 0.0825 inch square 0.315 inch long orifice) was 190°C, the weight of the 0.373 inch diameter piston, and 2. The weight is determined based on the combined weight of the 1607 plunger. The melt flow rate (MFR) of polypropylene is A. S. T. M. Volume 1238-
65T, except that the temperature is 230°C.

The equipment used to determine the melt index is
A. S. T. M
．． Defined in the handbook. Generally, polypropylene from the reaction vessel has an MFR of 1 or less, while polyethylene from the reaction vessel can have an MI of about 0.5 to 30.

Preferred monomers to be grafted onto C2-C8 polyolefins and other polymers to prepare the modifiers of the present invention are maleic anhydride, acrylic acid, methacrylic acid, glycidyl acrylate, hydroxy C2-C2O alkyl methacrylates and derivatives thereof. . Others that can be used are described elsewhere herein. However, other monomers may be added to the mixture to form the graft copolymer, such as maleic anhydride (MA), styrene, acid esters, salts, etc. M
A and styrene or MA and acrylic acid are preferred over MA alone when a polymer graft of MA is desired. The grafting reaction is preferably initiated by a free radical initiator of an organic peroxide compound.

Particularly preferred peroxides are t-butyl perbenzoate, digmyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxy-3-hexyne (LupersOnlO).
, α, α-bis(t-butylperoxydiisopropylbenzene (UlCupR')) or any free radical initiator with a half-life of 10 hours above 80°C or a mixture thereof. Generally, the decomposition temperature of the peroxide is The higher the better.Modern Plastics 1971, 11, which is cited here by reference for a more complete list of such compounds.
See pages 66-67 of May. A particularly preferred polymer is D
It is produced by the method described in OS2, 2l6, 7l8.

The grafting process is applicable to all types of elastomers that can be processed in an extruder.

Examples include natural rubber, polyisobutylene, butyl, chlorobutyl, polybutadiene, butadiene-styrene, ethylene-propylene, ethylene-propylene-diene terpolymer elastomers and mixtures thereof with each other or with thermoplastic polymers. Blends of elastomer and fluorine zinc in any proportion are particularly advantageous for processing by the preferred method. 30 to 80% by weight
5 to 85% by weight of an elastomer such as polypropylene, EPR or EPDM and 35 to 10% by weight of high density polyethylene.
, preferably 10 to 60, most preferably 10 to 3
A 0% by weight glass fiber fill is one of the preferred blends that benefits from several key properties with the addition of the modifier of the present invention.

The invention will be further illustrated by the following examples. Example 1 Various commercially available highly crystalline isotactic polypropylene compositions were prepared by adding either a commercially available nucleate, sodium benzoate, or a graft polymer modifier comprising acrylic acid grafted to polypropylene.
A series of polypropylene polymer compositions were prepared.

The graft had a melt flow rate of about 50, contained about 6% by weight grafted acrylic acid, and was produced by the extruder grafting method described above. Acrylic acid grafted polymers were generally tested at 1 to 10% by weight and the nucleation effect was calculated in various ways.

The results of these tests and calculations are summarized in Table 1. Table I above
As can be seen, the nucleating agent of the present invention reduces the size of spherulites to a size comparable to that obtained with commercially available nucleating agents.

Furthermore, the temperature of maximum crystallization of compositions containing the nucleating agents of the present invention is at least comparable to, and in some cases higher than, the temperatures obtained with commercially available nucleating agents. The maximum temperature is about 125°C. Furthermore, it can be seen that the time to maximum crystallization rate decreased more rapidly than the time for polymers containing no nucleating agent. Also, when using 10% by weight of the grafted acrylic acid polymer, a considerable improvement in the base polymer is observed, but the nearly comparable results are only 1.
It is noteworthy that only % by weight of the graft polymer can be obtained.

This represents one of the advantageous embodiments of the present invention in that only very small and therefore economical amounts of modifiers, such as nucleating agents, of the present invention are required. A direct comparison of the polypropylene formed with sodium benzoate and the polypropylene nucleated according to the present invention shows that the two are comparable in spherulite size.

Polypropylene nucleated according to the invention has very good crystallization temperature properties, and sodium benzoate has very good maximum crystallization times. All percentages used herein are by weight unless otherwise indicated. Some of the above modified polymers were further tested for flexural modulus, tensile strength and Izod impact energy.

The results are shown in the table below. As can be seen from the table below, the use of modifiers produces compositions of the invention with improved secant flexural modulus and tensile strength.

Regarding Izod impact strength, they are almost the same at very low temperatures, which is an important area for examining impact strength. Example 2 To demonstrate the significant synergistic effect of the additives of the invention used in relatively small amounts. In combination with various homopolymer glass-filled compositions used as homopolymers,
Enjay E-115” and “EnJayE-
A brand (variety) marked as ``117'' was used.

Both of these brands are highly crystalline in nature and have an E-
They are high molecular weight molded grade polypropylenes with the main difference being that 115 has an MFR of 5 and E-117 has an MFR of 12. To these compositions, a grafted homopolymer of polypropylene containing 6% by weight acrylic acid and having a melt flow rate of about 1.5 to 2.0
wt% added.

This variety was prepared by the extruder technique described above. E-
The composition produced from 115 was designated as D-540, and the composition produced from E-1
The composition produced from No. 17 was designated as D-541.

The polypropylene compositions of D-540 and D541 contained a total of about 0.10 to 0.20 weight percent acrylic acid grafted to the base polymer. These compositions were supplemented with 10% by weight of 1/4 inch Johns-Manville CS308A.
Glasses are blended and have a set of representative physical properties, e.g.
-115 and E-1 17 base compositions were determined for the compositions with added acrylic acid graft and the compositions with added glass fiber.

The results are summarized in Table I as follows. As is clear from Part 1 above, significant improvements in the physical properties of the base polymer were obtained with the addition of relatively small amounts of graft polymer modifier. Improvements in physical properties are particularly evident at heat deflection temperatures, where 66 psi and 264 p
It can be seen that when loading with si, synergistic improvements are obtained with the use of both glass fibers and modifiers. The above tests are known to those skilled in the art of plastic molding;
There is no need to describe this point in detail as it is a standard ASTM test. E-117 above, to show that in heat deflection tests, 100% grafted polypropylene performs no better than a homopolymer containing significantly less grafted polypropylene, i.e., a 5096 polypropylene/150% grafted polypropylene mixture.
A series of tests were carried out on polypropylene composition A containing 3% by weight of grafted acrylic acid having an MFR of 12 and a MFR of 12.

This corresponds to a 50/50 blend of 6% by weight graft and unmodified polypropylene. Composition B, a polypropylene composition containing 6% by weight acrylic acid and having an MFR of 10, was also used.

This corresponds to 100% modifier. The results are summarized in Table ■. Example 4 A further series of compositions and tests were conducted to demonstrate the effect of the modifiers of the present invention on impact blends.

Impact resistant polypropylene is used either with or without added glass. When using glass, the demand is in dishwashing pipes, washing machine lids, and other equipment where low warpage, impact strength, creep resistance, and hardness are important. Impact resistant varieties can be made from polypropylene by incorporating several polyethylene blocks into a polypropylene copolymer or by incorporating various blends of elastomers and high and low pressure polyethylene, as indicated herein. It can be produced by producing a copolymer in a reactor.

Impact blends containing 40% by weight ethylene-propylene copolymer, 40% by weight high density polyethylene and 20% by weight isotactic crystalline polypropylene were blended with homopolypropylene in various proportions.

When relatively large proportions of polypropylene were blended into this impact blend, a decrease in secant flexural modulus and tensile strength was observed. Impact properties are primarily measured by two different industrial tests.

One of these is the Izod impact test of the ASTM D-256-56 test. This is a test in which the pendulum is released to destroy the sample, and the force used to destroy it is calculated from the height reached by the pendulum. The Izot test is also performed on unnotched samples. Other impact tests are performed on the Gardner Modified Variable Height Impact Tester for Hard Plastics, Gardner Instrument Company, 5521 Lundy Lane, Bethesda, Maryland.

The test consists of dropping a 2 or 4 pound weight from a graduated height of 40 inches to produce a 1 pound impact force from 0 to 160 inches. Loss is defined as visible destruction of the target area. The number of plastic sheets to be tested is 30.
~125 mils thick. - Generally, according to the present invention, both the Izod and Gardner impact energies of 100% homopolypropylene are similarly reinforced by adding an impact concentrate to the acid-modified polypropylene within a certain range. as well, but without the large loss of stiffness seen with homopolypropylene.

However, when glass-filled homopolymers or glass-filled modified polymers are subjected to the conventional Gardner impact test at room temperature, the results are poor.

On the other hand, glass-filled reactor copolymers or impact-resistant varieties of polypropylene have good Gardner impact resistance, but
It lacks the stiffness, tensile strength and heat deflection temperature properties that even glass-filled homopolypropylene has.

Thus, a feature of the present invention is that certain blending techniques can be used to obtain good properties of both the glass-filled reactor copolymer and the glass-filled modified polypropylene.

To demonstrate the beneficial effects of modifiers on improving the secant modulus, tensile strength, and heat deflection temperature properties of impact blends, the above impact blends were included in this example, designated as "Impact Concentrate". Several compositions were made containing:

Two of these contained a small proportion of the same modifier as composition B, except that the MFR was 50.

This is referred to as composition C. The product composition was compared to a control without denaturant. Table V above summarizes the results in Table V below.
As can be seen, small amounts of modifier greatly improve the important properties of the impact blend.

Example 6 One of the problems in preparing glass-reinforced impact varieties that require either high Izot properties or high Gardner properties is that the two appear to be contradictory properties.

Izod properties are such that the adhesion of matrix fibers to glass fibers is beneficial to Izod impact, and the strong adhesion of Rikijin glass fibers to matrix compositions, improved by the presence of graft modifiers, is detrimental to Cardner impact. Both conflicting properties should be blended into the base polymer and modifier
A balance can be achieved by selecting the amount of tetrasexual concentrate.

A series of compositions were prepared and a number of physical properties of each, such as the relationship between deflection temperature and other important properties, and the relationship between Cardner impact properties and Izod impact properties, can be understood from the table below.

The following embodiments of the present invention can be considered.

(1) The crystalline polymer according to claim 1 is C
A composition that is a 2-C8 polyolefin.

(2) A composition in which the crystalline polymer is polypropylene. (3) A composition in which the carboxylic acid monomer according to claim 1 is acrylic acid.

(4) A composition according to claim 1, wherein the amount of grafted carboxylic acid in the composition is about 0.06 to 1% by weight.

(5)(a). Most of the crystalline polypropylene (5) is an acrylic acid grafted C2-C8 polyolefin containing about 0.1 to 15% by weight of grafted acrylic acid.
Polymer composition containing 1-15% by weight.

(5) A composition in which the polyolefin of item 5 contains polypropylene.

(7) A composition in which the derivative according to claim 1 is either a sodium salt or an aluminum salt.

(6) A composition in which the polypropylene of paragraph 6 comprises essentially the entire composition excluding conventional additives.

(9) The composition of item 5 contains a filler or reinforcing material.

(Self) A composition in which the reinforcing material is glass fiber.

00 The composition of item 5 also comprises an impact resistant component selected from the group consisting of elastomeric polyethylenes and combinations thereof.

(Self) A composition in which the elastomer of item 11 is an ethylene-propylene gopolymer.

A composition in which the crystalline polymer of claim 1 is an ethylene-propylene reactor copolymer.

The method according to claim 2, wherein the grafting acid is acrylic acid.

A method in which the grafted crystalline polymer according to claim 2 is a polyolefin.

(Self) The method according to item 15, wherein the crystalline polyolefin is crystalline polypropylene.

A method in which the ungrafted polymer according to claim 2 is crystalline polypropylene, and the grafted polyolefin according to claim 3 is acrylic acid grafted polypropylene.

(auto)-A method in which the grafted acrylic acid of item 17 is present in an amount of about 2 to 8% by weight of the grafted polymer.

(Self) The amount of all graft monomer components in the polymer blend after adding the graft nucleating agent of item 18 is approximately 0.06
or 1% by weight.

(to) A method in which the derivative according to claim 2 is a sodium salt.

(Incorporated) A method in which the derivative according to claim 2 is an aluminum salt.

E2) The graft component in item 18 is poly(acrylic acid)
How to be sodium.

E3) A method in which the graft component according to claim 2 is poly(acrylic acid) aluminum.

(b) A method in which the crystalline polymer according to claim 2 contains a reinforcing material or a filler component. 5. The method of item 24, wherein the filler component is glass fiber.

(1) A method in which the crystalline polymer of item 18 contains a reinforcing material or a filler component.

@The method of Item 26, wherein the filler component is glass fiber.

(6) A method in which the derivative according to claim 2 is acrylic acid or glycidyl methacrylate.

(4) A method in which the derivative according to claim 2 is acrylic acid or glycidyl methacrylate. (1) A method in which the composition of claim 2 also contains an impact-resistant surround component selected from the group consisting of elastomers, polyethylenes, and combinations thereof. (9) The composition of paragraph 18 also contains an impact-resistant component selected from the group consisting of elastomers, polyethylenes, and combinations thereof.

(Su) The composition of paragraph 29 also contains an impact-resistant component selected from the group consisting of elastomers, polyethylenes, and combinations thereof.

(b) Does the modifier according to claim 2 mainly function as a nucleating agent, and the crystalline polymer has a nucleated form? How to be a breed.

The method of item 18, wherein the modifier primarily functions as a nucleating agent, and the polypropylene is of a nucleating variety.

(a) A method in which the polypropylene modifier of item 18 is grafted with a glycidine derivative. 1. The method according to item 35, wherein the derivative is glycidyl acrylate.

Claims (1)

[Claims] 1 A method for improving the properties (including crystallization rate) of a composition containing ungrafted crystalline polypropylene, the method comprising: (a) adding 0.1 to 15% by weight of a grafted polyolefin to said crystalline polypropylene; (b) melting the crystalline polypropylene; and (c) melting the crystalline polypropylene. wherein the composition further comprises an impact component selected from olefin elastomers, polyethylene and mixtures thereof, wherein the blend is cooled to the crystallization temperature of the blend and the modifier forms very small spherulites. A method characterized by comprising: