JP2003507498A - Method for preparation of polyamide nanocomposite composition by in situ polymerization - Google Patents

Abstract

(57) Abstract In-situ polymerization of polyamide monomers and silicate materials produces polyamide nanocomposites with desired physical properties. The nanocomposites produced include homopolymers and copolymers. The choice of monomer, silicate type, and polymerization conditions can alter the properties of the nanocomposite.

Description

Detailed Description of the Invention

[0001]   Field of the invention   The present invention is directed to a polyamide matrix having treated silicates dispersed therein.
The present invention relates to a nanocomposite material containing a composite. In more detail
Ming is a silicate material treated with at least one ammonium ion
Relates to nanocomposite materials dispersed in.

[0002]   BACKGROUND OF THE INVENTION   International application WO 93/04118 has platelet particles therein.
Disclosed is a method of preparing a polymer nanocomposite that is dispersed in a matrix. This way
Is an intercalated laminate that is swellable and compatible with polymers.
 A shear rate sufficient to melt process the layered material) and dissociate it
Includes frequent calls. Having the function of silane or the function of onium cation 1
Compatibilizing the laminate material with one or more "effective swell / compatibilizers".

International application WO 93/04117 discloses a method for preparing a polymer nanocomposite having platelet particles dispersed therein, the polymer and an insertable laminate material that is swellable and polymer compatible. Is melt processed. The laminating materials are compatibilized by one or more "effective swell / compatibilizers" selected from primary ammonium, secondary ammonium and quaternary phosphonium ions. The selected swelling / compatibilizer promotes exfoliation (which makes the surface of the material more organophilic than that compatibilized by the tertiary and quaternary ammonium ion complexes) and shear during mixing This results in lower stress and degradation of the polymer, making the composite more thermally stable than other cation (such as quaternary ammonium cation) swell / compatibilizers.

International patent application WO 94/22430 discloses a nanocomposite material having a polyamide matrix comprising at least one gamma phase polyamide in which a matrix of nanometer-scale particulate material is dispersed. There is. By adding particulate material to nylon 6, compared to unfilled nylon 6,
The result was improved flexural modulus and flexural strength (7 to 35%). The addition of particulate material to nylon 6,6 resulted in little improvement in flexural modulus and strength (1 to 3%) compared to unfilled nylon 6,6.

International patent application WO 93/100098 discloses a polymer composite made by melt processing a polymer with an insertable laminate material that is swellable and polymer compatible, the material being on the surface of the layer. It includes a layer having a reactive organosilane species covalently bound thereto.

International patent application WO 95/14733 discloses a method of producing a polymer composite that does not exhibit a melting or glass transition by melt processing a polymer with a laminated gallery-containing crystalline silicate. Examples of this are intercalated sodium silicate and crystalline poly (ethylene oxide), montmorillonite intercalated with quaternary ammonium and polystyrene, and montmorillonite intercalated with quaternary ammonium and nylon 6.

None of the above references (alone or in combination) discloses the claimed invention.

SUMMARY OF THE INVENTION The present invention relates to polymer nanocomposite compositions suitable for automotive, electronics, film and fiber applications where a combination of tensile strength, tensile modulus and flexural modulus is required. It is a thing. In addition, the claimed polymer nanocomposite compositions have the desired surface appearance, toughness, ductility and dimensional stability. This composition is well processed and resistant to a wide range of molding conditions.

Such a polymer nanocomposite composition comprises a polyamide and a treated silicate, the treated silicate comprising a silicate material treated with at least one ammonium ion of the formula:

[0010]         ⁺NR₁R_TwoR_ThreeR_Four R in the above formula₁, R_Two, R_ThreeAnd R_FourIs saturated or unsaturated C₁To C₂₂Carbonized water
Independently selected from the group consisting of elementary, substituted and branched hydrocarbons
Or R₁And R_TwoForms an N, N-cyclic ether. In this example,
Saturated or unsaturated alkyl, including alkylene, hydroxyalkyl, alkoxy
Alkyl, alkoxy, aminoalkyl, acid alkyl, halogenated alkyl, sulfur
Substituted alkyls such as alkyl halides and alkyl nitrates, branched alkyls
Alkyl, alkylaryl, alkoxyaryl, alkylhydroxyaryl
, Aryl such as alkylalkoxyaryl and substituted aryl
. Optionally R₁, R_Two, R_ThreeAnd R_FourOne of them is hydrogen. In detail below
Described milligrams of treated silicate per 100 grams of silicate treated
Rum (MER) is approximately 10 milliequivalents / cation exchange capacity of the untreated silicate /
From 100 g lower, about 30 mm from the cation exchange capacity of untreated silicate
Equivalent / up to 100g. Testing composite polymer matrix materials
Then the tensile strength is increased, compared to that of the polymer without the treated silicate.
The tensile and flexural moduli are improved without a significant decrease in
As used herein, "significantly lowers" means a statistically determined deviation.
Means a drop over.

The present invention further relates to a method for preparing the polymer nanocomposite composition described above, which method comprises forming a flowable mixture of polyamide and treated silicate material, and at least about 50 of the treated silicate. % (But not all) is dissociated (this term is described in detail below). The treated silicate is a silicate material treated with at least one ammonium ion of the formula:

[0012]         ⁺NR₁R_TwoR_ThreeR_Four R in the above formula₁, R_Two, R_ThreeAnd R_FourIs saturated or unsaturated C₁To C₂₂Carbonized water
Independently selected from the group consisting of elementary, substituted and branched hydrocarbons
Or R₁And R_TwoForms an N, N-cyclic ether. In this example,
Saturated or unsaturated alkyl, including alkylene, hydroxyalkyl, alkoxy
Alkyl, alkoxy, aminoalkyl, acid alkyl, halogenated alkyl, sulfur
Substituted alkyls such as alkyl halides and alkyl nitrates, branched alkyls
Alkyl, alkylaryl, alkoxyaryl, alkylhydroxyaryl
, Aryl such as alkylalkoxyaryl and substituted aryl
. Optionally R₁, R_Two, R_ThreeAnd R_FourOne of them is hydrogen. In detail below
Described milligrams of treated silicate per 100 grams of silicate treated
Rum (MER) is approximately 10 milliequivalents less than the cation exchange capacity of the untreated silicate.
/ 100g to about 30 milliequivalents, which exceeds the cation exchange capacity of untreated silicates
Up to / 100 g. Tested composite polymer matrix material, processed
Significantly reduced tensile strength compared to that of polymers without silicates
Without any increase in tensile and flexural moduli.

Description of the Preferred Embodiments of the Invention The polyamide of the present invention is a synthetic linear polycarbonamide, which is the presence of repeating carbonamide groups as an integral part of the polymer chain separated from each other by at least two carbon atoms. Characterized by This type of polyamide is
It can be obtained from diamines and diacids, including polymers commonly known in the art as nylons, having repeating units represented by the following general formula:

—NHCOR ₅ COHNR ₆ — wherein R ₅ is an alkylene group of at least 2 carbon atoms (preferably about 2 to about 11), or at least about 6 carbon atoms (about 6 to about 6). 17 are preferred) and R ₆ is selected from R ₅ and aryl groups. Also included are copolyamides, terpolyamides, etc. obtained by known methods, for example by condensation of a mixture of hexamethylenediamine and a diacid consisting of terephthalic acid and adipic acid. The aforementioned polyamides are well known in the art and include, for example, poly (hexamethylene adipamide) (nylon 6,6).
, Poly (hexamethylene sebacamide) (nylon 6,10), poly (hexamethylene isophthalamide), poly (hexamethylene terephthalamide), poly (heptamethylene pimeramide) (nylon 7,7), poly (octa Methylene suberamide) (nylon 8,8), poly (nonamethylene azamide) (nylon 9,9)
, Poly (decamethylene sebacamide) (nylon 10,9), poly (decamethylene sebacamide) (nylon 10,10), poly [bis (4-aminocyclohexyl) methane 1,10-decanecarboxamide)] , Poly (m-xylene adipamide), poly (p-xylene sebacamide), poly (2,2,2-trimethylhexamethylene terephthalamide), poly (piperazine sebacamide), poly (p-phenylene terephthalate) Amides), poly (metaphenylene isophthalamide), and copolymers and terpolymers of the aforementioned polymers. Other polyamides include
There are nylon 4,6, nylon 6,9, nylon 6,10, nylon 6,12, nylon 11, nylon 12, amorphous nylon, aromatic nylon and copolymers thereof.

Other useful polyamides are those formed by the polymerization of amino acids and their derivatives such as lactams. Examples of these useful polyamides are poly (
Caprolactam) (nylon 6), poly (4-aminobutyric acid) (nylon 4), poly (7-aminoheptanoic acid) (nylon 7), poly (8-aminooctanoic acid) (
Nylon 8), poly (9-aminononanoic acid) (nylon 9), poly (10-aminodecanoic acid) (nylon 10), poly (11-aminoundecanoic acid) (nylon 11), poly (12-aminodocecanoic acid) (nylon) 12) etc.

A preferred polyamide is Vydyne® nylon, which is poly (hexamethylene adipamide) (nylon 6,6), for the applications contemplated herein, tensile strength , A composite material having the desired combination of tensile and flexural moduli (Vydyne® is Solutia).
, Inc. Is a registered trademark of).

The preferred molecular weight of the polyamide is in the range of 30,000 to 80,000 D (weight average), more preferably at least 40,000 D (weight average). Increasing the weight average molecular weight of the polyamide from about 35,000 to 55,000 D results in an unexpected increase in toughness, as shown by the notched Izod impact test. The toughness increases slightly as the weight average molecular weight of the polyamide in the polyamide neat increases from about 35,000 to 55,000D, while a similar increase in the molecular weight in the nanocomposite increases the toughness about twice. Will result. Therefore, the increase in toughness in the nanocomposite is even greater than that of polyamide neat.

In a preferred embodiment, the polyamide has a ratio of amine end groups to acid end groups greater than 1. More preferably, the concentration of amine end groups is at least 10 mol% higher than the concentration of carboxylic acid end groups. In a more preferred embodiment, the polyamide has a concentration of amine end groups that is at least 20 mol% higher than the concentration of carboxylic acid end groups, and in the most preferred embodiment the polyamide has a concentration of amine end groups that is at least 30% higher than the concentration of carboxylic acid end groups. Mol% higher. In another preferred embodiment, the concentration of amine end groups is about equal to the concentration of carboxylic acid end groups.

Among the preferred embodiments are nylon 6, nylon 6,6, blends thereof and copolymers thereof. The range of nylon 6 to nylon 6,6 ratio in the formulation is about 1/100 to 100/1. This range is about 1/10 to 10/1
Is preferred. The range of nylon 6 to nylon 6,6 ratio in the copolymer is about 1/100 to 100/1. This range is preferably about 1/10 to 10/1.

Optionally, the nanocomposite composition comprises at least one additional polymer. Examples of suitable polymers are polyethylene oxide, polycarbonate, polyethylene, polypropylene, poly (styrene-acrylonitrile), poly (acrylonitrile-butadiene-styrene), poly (ethylene terephthalate), poly (
Butadiene terephthalate), poly (trimethylene terephthalate), poly (ethylene naphthalate), poly (ethylene terephthalate-co-cyclohexanedimethanol terephthalate), polysulfone, poly (phenylene oxide)
Alternatively, poly (phenylene ether), poly (hydroxybenzoic acid-co-ethylene terephthalate), poly (hydroxybenzoic acid-co-hydroxynaphthalic acid), poly (ester amide), poly (ether imide), poly (phenylene sulfide) , Poly (phenylene terephthalamide).

The mixture may include various optional ingredients that are commonly used additives for polymers. Such optional ingredients include surfactants, nucleating agents, coupling agents, fillers, impact modifiers, chain extenders, plasticizers, compatibilizers, colorants, mold release lubricants, Antistatic agents, pigments, flame retardants, etc.

Suitable examples of fillers are carbon fiber, glass fiber, kaolin clay, wollastonite and talc. Suitable examples of compatibilizers include acid modified hydrocarbon polymers such as maleic anhydride grafted prepyl ethylene, maleic anhydride grafted ethylene butylene styrene block copolymers. Suitable examples of mold release lubricants are alkyl amines, stearamides, and aluminum di- or tristearate.

Suitable examples of impact modifiers include ethylene propyl rubber, ethylene propyl diene rubber, methacrylate butadiene styrene (having a core-shell morphology), poly (butyl acrylate) with or without carboxyl modification.
, Poly (ethylene acrylate), poly (ethylene methacrylate), poly (ethylene acrylic acid), poly (ethylene acrylate) ionomer, poly (ethylene methacrylate acrylic acid) terpolymer, poly (styrene-butadiene) block copolymer, poly (styrene-) Butadiene-styrene) block terpolymers, poly (styrene-ethylene / butadiene-styrene) block terpolymers and poly (styrene-ethylene / butadiene-styrene carboxylate)
There are block terpolymers.

Silane coupling agents are well known in the art and are useful in the present invention. Examples of suitable coupling agents are octadecyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane.
Aminopropylphenyldimethoxysilane, γ-glycidoxypropyltripropoxysilane, 3,3-epoxycyclohexylethyltrimethoxysilane, γ
-Proprionamidotritoxysilane, N-trimethoxysilylpropyl N (
β-aminoethyl) amine, trimethoxysilylundecylamine, trimethoxysilyl-2-chloromethylphenylethane, trimethoxysilylethylphenylsulfonyl azide, N-trimethoxysilylpropyl-N, N, N-trimethylammonium chloride, N- (trimethoxysilylpropyl) -N-methyl-N
, N-diallyl ammonium chloride, trimethoxysilylpropyl cinnamate,
Examples include 3-mercaptopropyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane. The preferred silane is γ-aminopropyltriethoxysilane. Optionally, a silane coupling agent is added to the laminated silicate at about 0.
Add to the polymer composite in the range of 5 to 5% by weight. The preferred concentration range of the silane coupling agent is about 1 to 3% by weight of the silicate material in the composite.

[0025] In one embodiment, the nanocomposite composition further comprises a composition in which the acid end of the polyamide is attached to the surface of the treated laminated silicate by a silane coupling agent.

The silicate material of the present invention is selected from the group consisting of laminated silicates and fibers, chain-like silicates, including phyllosilicates. Examples of fibers, chain-like silicates include chain-like minerals such as sepiolite and attapulgite, with sepiolite being preferred. Such silicates are described, for example, in Japanese patent application Kokoku 6-84435 published on October 26, 1994. Examples of laminated silicates are montmorillonite, nontronite, beidellite,
There are folkonscoites, Laponite® synthetic hectorites, natural hectorites, saponites, sauconites, magadites, and laminated smectite clay materials such as Kenyaite, fermicrite. Other useful materials include laminated illite materials such as Ladykite, and mixtures of illite and one or more of the aforementioned clay materials. Preferred laminated silicates are montmorillonite, nontronite, beidellite, folconscoite,
Laponite® is a laminated smectite clay material such as synthetic hectorite, natural hectorite, saponite, sauconite, magadaite, and kenyaite.

Laminated silicate materials suitable for use in the present invention are well known in the art and are sometimes referred to as “swellable laminated materials”. A further description of the claimed laminated silicates and platelets formed when melt processed with polyamides is included in International Patent Application WO 9
Seen on 3/04117. Laminated silicate materials typically have planar layers arranged in a coherent, coplanar structure, with the bonds in the layers such that when processed the material exhibits increased spacing between the interlayers. Stronger than the bond between different layers.

The laminated silicate material requires treatment with the ammonium ions of the present invention as described in detail below, and the swelling and / or intermediate layer swellability required for the performance of the treated silicates of the present invention. Or provide an interval. As used herein, "intermediate layer spacing" is the distance between the layers' surfaces. This is because these layers are assembled in the treated material before any delamination (ie delamination) occurs. Preferred clay materials are intermediate layers or Li ⁺ , Na ⁺ ,
It generally contains exchangeable cations such as Ca ⁺² , K ⁺ , Mg ⁺² . In this state, these materials have interlayer spacings that delaminate to a low extent only in the host polymer melt, typically about 4 A or less and independent of mixing. In the claimed embodiment, the cationic treating agent is capable of exchanging with intermediate cations such as Li ⁺ , Na ⁺ , Ca ⁺² , K ⁺ , Mg ⁺² to improve delamination of the laminated silicate. Is.

The treated silicates of the present invention are the aforementioned silicate materials treated with at least one ammonium ion of the formula:

[0030]         ⁺NR₁R_TwoR_ThreeR_Four R in the above formula₁, R_Two, R_ThreeAnd R_FourIs saturated or unsaturated C₁To C₂₂Carbonized water
Independently selected from the group consisting of elementary, substituted and branched hydrocarbons
Or R₁And R_TwoForms an N, N-cyclic ether. In this example,
Saturated or unsaturated alkyl, including alkylene, hydroxyalkyl, alkoxy
Alkyl, alkoxy, aminoalkyl, acid alkyl, halogenated alkyl, sulfur
Substituted alkyls such as alkyl halides and alkyl nitrates, branched alkyls
Alkyl, alkylaryl, alkoxyaryl, alkylhydroxyaryl
, Aryl such as alkylalkoxyaryl and substituted aryl
. Optionally R₁, R_Two, R_ThreeAnd R_FourOne of them is hydrogen. According to the present invention
Thus, mixtures of two or more ammonium ions are contemplated.

[0031]   In a preferred embodiment of the invention R₁Is hydrogenated tallow, unsaturated tallow or less
Both selected from the group consisting of hydrocarbons having 6 carbons, R_Two, R_ThreeAnd R _Four Independently has 1 to 18 carbon atoms. Tallow consists mainly of octadecyl chains.
It has a small amount of homologues and an average degree of unsaturation of 1 to 2. Rough composition
Is C₁₈Is 70%, C₁₆Is 25%, C₁₄Is 4% and C₁₂Is 1%.
In another preferred embodiment of the invention, hydrogenated tallow, unsaturated tallow or at least
R from the group consisting of hydrocarbons having 6 carbons₁And R_TwoIs selected, R_ThreeOh
And R_FourIndependently has 1 to 12 carbons.

Examples of suitable R ₁ , R ₂ , R ₃ and R ₄ groups are alkyl, such as methyl, ethyl, octyl, nonyl, tert-butyl, ethylhexyl, neopentyl, isopropyl, secondary butyl, dodecyl, 1 -Alkenyl such as propenyl, 1-butenyl, 1-pentynyl, 1-hexynyl, 1-heptenyl and 1-octenyl, cycloalkyl such as cyclohexyl, cyclopentyl, cyclooctyl and cycloheptyl, alkoxy such as ethoxy and hydroxyalkyl, methoxymethyl , Alkoxyalkyl such as ethoxymethyl, butoxymethyl, propoxymethyl, pentoxybutyl, phenoxyphenyl, phenoxymethyl, phenoxydecyl,
Allyloxyalkyl and aryloxyaryl such as phenoxyoctyl, arylalkyl such as benzyl, phenylethyl, 8-phenyloctyl, 10-phenyldecyl, alkylaryl such as 3-decylphenyl, 4-octylphenyl and nonylphenyl.

Preferred ammoniums for treating silicate materials include dimethyldi (hydrogenated tallow) ammonium, dimethylbenzyl hydrogenated tallow ammonium, dimethyl (
Ethylhexyl) tallow ammonium hydride, trimethylammonium tallow ammonium, dimethylbenzyldi (hydrogenated tallow) ammonium, N, N-2-cyclobutoxydi (hydrogenated tallow) ammonium, trimethyltallow ammonium, methyldihydroxyethyl tallow ammonium, octadecyl Onium such as methyldihydroxyethylammonium and dimethyl (ethylhexyl) tallow ammonium hydride,
And there are mixtures of these. Particularly preferred ammonium includes quaternary ammonium such as dimethyldi (hydrogenated tallow) ammonium, dimethylbenzyldihydrogenated tallow ammonium, methyldihydroxyethyl tallow ammonium, octadecylmethyldihydroxyethylammonium, dimethyl (ethylhexyl) tallow ammonium and the like. There are mixtures of these.

Treatments with ammonium ions, also referred to as “cationic treatments”, can include introducing ions into the silicate material by ion exchange. In the embodiment where the silicate material is a laminated silicate, the cationic treating agent can be introduced between the respective layers (almost all layers), i.e. between most layers of the laminated material, and thus the result The resulting platelet layer contains less than about 20 particles in its thickness. The platelet layer is preferably less than about 8 particles in thickness, more preferably less than about 5 particles in thickness, and most preferably about 1 or 2 particles in thickness. Is.

The treated silicates have a MER from about 10 milliequivalents / 100 g, which is less than the cation exchange capacity of the untreated silicates, to about 30 milliequivalents / 100 g, which exceeds the cation exchange capacity of the untreated silicates. MER is the milliequivalent amount of treatment per 100 grams of silicate. Each untreated silicate has a cation exchange capacity, which is the milliequivalent amount of cation available for exchange per 100 grams of silicate. For example, the cation exchange capacity of laminated silicate montmorillonite may be about 95, and the exchange capacity of sepiolite ranges from about 25 to 40. When the MER of the treated silicate substantially exceeds the cation exchange capacity,
There is an excess of cationic treating agent available for reaction with the polyamide. This excess can cause deterioration of the properties of the polyamide.

The higher the MER, the lower the concentration of silicate in the treated silicate. Thus, the first nanocomposite sample may have a higher concentration of treated silicate but a lower concentration of silicate than the second nanocomposite sample. This is because the first sample has a higher MER than the second sample.

When the MER value of the treated silicate is substantially below its exchange capacity (eg about 85 MER for the preferred montmorillonite), few cationic treating agents have any useful effect. If the MER is greater than about 125, excess ammonium can impair the properties of nylon. When the untreated montmorillonite has an exchange capacity of 95, the treated laminated silicate has a viscosity of about 85 to about 1.
It is preferred to have a cation exchange capacity of 25.

The amount of treated silicate contained in the composition is about 0.1 to 12 of the composite material.
It is in the range of% by weight. The concentration was adjusted to provide a composite polymer matrix material, which (when tested) exhibits increased tensile and flexural moduli with no reduction in tensile strength. Increase in tensile and flexural modulus is at least about 1
It is preferably 0%. More preferably, the increase in tensile modulus and flexural modulus is at least about 20%. Too little treated silicate will not provide the desired increase in tensile and flexural modulus. Too much treated silicate provides a polyamide composite with reduced tensile strength. further,
It may be desirable to have a crystalline region of polyamide in the nanocomposite composition that is less than 1.0 μm.

The particle size of the treated silicate is such that it promotes optimal contact between the polymer and the treated silicate. The particle size range may be from about 10 microns to about 100 microns. The particle size is preferably in the range of about 20-80 microns. Most preferably, the particle size is less than about 30 microns (eg, through a 450 mesh screen) and the resulting polymer nanocomposite has improved efficacy properties.

Optionally, the silicate can be treated with a mixture of one or more ammonium ions of the formula below and one or more quaternary ammonium ions.

[0041]         ⁺NR_aR_bR_cR_d R in the above formula_a, R_bAnd R_cAt least one of hydrogen (H) is R_dIs saturated
Or unsaturated C₁To C₂₂Hydrocarbons, substituted hydrocarbons and branched
It is selected from the group consisting of hydrocarbons. This example includes saturated alkylene or
Unsaturated alkyl, hydroxyalkyl, alkoxyalkyl, alkoxy, amine
Alkyl, acid alkyl, alkyl halide, sulfonated alkyl, nitrated alkyl
Substituted alkyl, such as rualkyl, branched alkyl, alkylaryl,
Alkoxy aryl, alkyl hydroxy aryl, alkyl alkoxy aryl
Aryl and substituted aryl. Ammonium ion mentioned above
R_dThe definition of the group is R in ammonium ion_FourSince it is generally the same as the definition of radical,
(In this embodiment, quaternary ammonium), R_FourAlso the above example of the radical
R_d2 is an exemplary group. Optionally R_dThe group further contains a carboxylic acid moiety.
Only ammonium ion         ⁺NR_aR_bR_cR_d Is an amino acid (eg, 12-ammonium laurate). In this embodiment
It is especially preferred that the ratio of amine end groups to acid end groups of the polyamide is greater than 1.
Yes.

A preferred mixture comprises at least one of dimethyldi (tallow hydride) ammonium, methyldihydroxyethyl tallow ammonium and / or dimethyl (ethylhexyl) tallow ammonium hydride, alone or in combination with ammonium 12-laurate.

Optionally, the treated silicate can be further treated with an azine cationic dye such as nigrosine or anthracin. The cationic dye should provide color fixation and color uniformity and should further increase the intercalation of polymer molecules.

It is further desirable to have a polymeric composite that has both the desired strength and flexibility and is lighter in weight. This is achieved by minimizing the concentration of treated silicate in the nanocomposite. A preferred nanocomposite comprises about 0.1 to about 12.0% by weight of the composite of a treated silicate concentrate. The most preferred nanocomposite comprises from about 0.5 to about 6.0% by weight of the composite of treated silicate concentrate.

In a first embodiment of the invention, a nanocomposite composition is prepared using a two-step method. One step involves forming a flowable mixture of polyamide as polymer melt and treated silicate material. Another step involves dissociating at least 50% (but not all) of the treated silicate material. As used herein, the term "dissociate" means to delaminate or separate the treated silicate material into submicron scale structures that contain individual or small numbers of units. In embodiments using laminated silicates, this dissociation step comprises delaminating the treated silicate material into submicron scale platelets, which may contain multiple individual or small layers.
In embodiments that use fibre, chain-like silicates, this dissociation step comprises separating the treated silicate material into submicron scale fibrous structures that include individual or small multiple units.

As mentioned in the mixture forming step, a flowable mixture is a mixture capable of dispersing dissociated treated silicate material on a submicron scale. A polymer melt is a melt processable polymer or mixture of polymers that has been heated to a temperature high enough to produce a viscosity low enough to cause submicron scale mixing. The processing temperature must be at least as high as the melting point of the polyamide used and below the decomposition temperature of the polyamide and the organic treatment temperature of the silicate. The actual extrusion temperature may be at least below the melting point of the polyamide used. This is because the heat is generated by the flow. The processing temperature is high enough so that the polymer remains in the polymer melt during the performance of the process. In the case of crystalline polyamide, the temperature is above the melting temperature of the polymer. For example, a typical nylon 6 having a melting point of about 225 ° C can be melted in an extruder at any temperature above about 225 ° C (eg, between about 225 ° C and about 260 ° C). For nylon 6,6, temperatures of about 260 ° C to about 320 ° C are preferably normally used.

The flowable mixture can be formed using conventional methods. For example, flowable mixtures can be prepared by using conventional polymers and additive compounding means, heating the polymer to a temperature sufficient to form a polymer melt, for example a Banbury® type mixer. , Brabender (
In a suitable mixer, such as an extruder, such as a (registered trademark) type mixer, a Farrel (R) continuous mixer, combine with the desired amount of treated silicate material in the form of granules or powder.

In one embodiment, the flowable mixture can be formed by mixing the polyamide and the previously formed treated silicate-containing concentrate. The concentrate comprises treated silicate and polymeric carrier. The concentration of treated silicate material in the concentrate is selected to provide the desired treated silicate concentration in the final nanocomposite composition. Examples of suitable polymers for the carrier polymer of the concentrate are polyamide, ethylene propylene rubber, ethylene propylene diene rubber, ethylene ethyl acrylate, ethylene ethyl methacrylate or ethylene methacrylate. Examples of this include Iotek® ionomer and Esc
There are also or® ATX acid terpolymers, both available from Exxon. Suitable polyamide polymers for the carrier polymer include nylon 6 and nylon 6
, 6, nylon 4,6, nylon 6,9, nylon 6,10, nylon 6,12
, Nylon 11, nylon 12, amorphous nylon, nylon such as aromatic nylon, and copolymers thereof. The carrier polymer may be the same as or different from the polyamide of the flowable mixture. For example, both polymers may be polyamides (especially nylon 6,6) but may have the same or different molecular weights. The preferred weight average molecular weight of the carrier polymer of the concentrate is about 5
The range is from 1,000 D to about 60,000 D. The most preferred range of weight average molecular weight for the carrier polymer is in the range of about 10,000D to about 40,000D. In this embodiment, the dissociation step of the method of the invention described above may occur at least in part through the formation of a concentrate such that the dissociation step may precede the step of forming a flowable mixture. . Thus, it is understood that the steps (eg, formation and dissociation) of the method can occur sequentially, either simultaneously or in any combination thereof. In the second step, the flowable mixture is thoroughly mixed to form a dissociated silicate dispersed nanocomposite structure in the polymer melt, which is then cooled. The silicate can be dissociated by subjecting it to a shearing machine with an effective shear rate. As used herein, an effective shear rate refers to the nearly homogeneous distribution of silicates that aids their dissociation and that the individual units (eg, platelets or fiber chains) are substantially unbroken. A shear rate effective to provide a composition comprising a polyamide matrix having a silicate.

Any method that can apply shear stress to the flowable mixture or any polymer melt can be used. The shearing action can be provided by any suitable method such as mechanical means, heat shock, pressure modification, or ultrasound. Stirrer, Banbury® type mixer, Brabe
nder (registered trademark) type mixer, Farrel (registered trademark) continuous mixer,
And the flowable polymer mixture is preferably sheared by a mechanical method of flowing a portion of the melt to another portion of the mixture by using mechanical means such as an extruder. Most preferably, the mixture is subjected to multiple shears. In addition to the increased shear stress provided by multiple shears, a greater residence time is also provided, which results in improved efficacy properties. Other procedures use heat shock. In this, alternatively, by raising or lowering the temperature of the mixture (
Shear stress is obtained, which causes thermal expansion, which leads to internal stresses that cause shear). In yet another procedure, shear stress is obtained by ultrasonic techniques in which a portion of the mixture is oscillated or excited in different phases and then sheared by sudden pressure changes, cavitation or resonant oscillations of the pressure modification method. These methods of shearing flowable polymer mixtures and polymer melts are merely exemplary of useful methods, using any method known in the art for shearing flowable polymer mixtures and polymer melts. can do.

Shearing can be accomplished by introducing polymer pellets at one end of an extruder (single or twin screw) and receiving the sheared polymer at the other end of the extruder. A preferred twin screw extruder is Werner and Pfle.
It is a co-rotating perfect intermesh type, such as ZSK manufactured by the Iderer Company. The laminated silicate can be fed to the feed throat or downstream vent of a twin screw extruder. A preferred method is to feed the downstream vent with laminated silicates, which produces composite polymers with improved potency properties.

Optionally, additional processing steps such as solid state polymerization can be added and the compounded pellets are held at an elevated temperature below the melting point of the polymer for several hours. For example, typical solid state polymerization conditions are heating the solid polymer in the range of about 200 to 240 ° C. for about 2 to 5 hours. The additional processing steps result in increased molecular weight and improved toughness, ductility and tensile strength of the nanocomposite.

Another optional processing step may be a heat treatment step, heating the composition to improve the insertion of nylon molecules into the silicate structure. The heat treatment step is performed by heating the composition at a temperature in the range of about 200 to 240 ° C. for about 2 to 5 hours.

Another preferred continuous compounder is the Farrel Continuous Mix.
r (FCM). For compositions using Vydyne® 21 nylon, the preferred temperature of the melt is in the range of about 275 to 315 ° C, and the most preferred range is about 275 to 295 ° C.

Reactive extrusion can also form polymer melts containing nanodispersed dissociative silicate materials. In this, the silicate material is first dispersed as an agglomerate, ie as a nanoscale liquid or solid monomer, and then this monomer is polymerized in an extruder or the like. Alternatively, the polymer can be granulated and dry mixed with the treated silicate material and then the composition heated in a mixer until the polymer melts to form a flowable mixture.

The method for forming the nanocomposite is preferably carried out in the absence of air, for example in the presence of an inert gas such as argon, neon or nitrogen. The process can be carried out in a batch or discontinuous manner, for example by carrying out the reaction in a sealed vessel. As an alternative, the process is carried out in a continuous manner in one processing zone, for example using an extruder in which the air is largely excluded, or in a plurality of such reaction zones in series or in parallel. It can be performed.

In another embodiment of the present invention, a method for preparing a polymeric nanocomposite composition comprises forming a first flowable mixture of polyamide, at least one monomer, and a treated silicate material, At least 5 of treated silicate materials
Includes 0% (but not all) dissociation and polymerizing the monomers. It is understood that in the method of this embodiment, the polymerizing step may occur simultaneously or sequentially with one or more other steps. At least one monomer of the third embodiment preferably comprises monomers such as ε-caprolactam, lauryllactam, and their corresponding lactones.

In another embodiment of the present invention, a method for preparing a polymer nanocomposite composition comprises forming a flowable mixture of polyamide and treated silicate material, at least 50% of the treated silicate material ( Dissociating (but not all) and adding an additional amount of the polyamide (most preferably during the dissociation step).

In each of the foregoing embodiments of the method for preparing the polymer nanocomposite composition, an additional step of solid phase polymerization (ie, composition that increases residence time in the mixer and removes water condensation products) is added. Additional steps or treatments, such as melt polymerization) may follow.

The compositions of the present invention can be made into, but not limited to, fibers, films or molded articles.

Examples The following examples are provided to further illustrate the present invention and are not intended to limit the scope of the claims in any way.

The nylons used in the following examples are all nylon 6,6. Unless otherwise indicated, the nylon is from Solutia, Inc. Nylon h manufactured by K.K. was used, and the characteristic values are shown in the following nylon type table. All percentages are weight percentages unless otherwise indicated. Clay% is the total weight of untreated clay in the final composite, whether untreated or pretreated. Tensile strength and Young's modulus were measured according to ASTM method D638 and are reported in kpsi and MPa. Flexural modulus was measured according to ASTM method D790, kpsi and M
Reported in Pa.

[0062]   Work numbers with "-c" are control standards.

Clay-type Table 1 Unless otherwise indicated, all silicates shown below are South
ern Clay Products Inc. Montmorillonite having a clay exchange capacity of about 95 manufactured by. The treatment indicated below is an ammonium treatment. Items AH are controls, while items I-AA are examples of quaternary ammonium treated silicates of the invention.

[0064]

[Table 1]

Clay-type Table 2 Items GG to NN, unless otherwise indicated, are examples of montmorillonites of the present invention treated with a plurality of quaternary ammonium or a blend of quaternary ammonium and ammonium. Items OO through TT are examples of the tertiary ammonium silicates of this invention.

[0066]

[Table 2]

[0067]

[Table 3]

Amine end and acid end are the equivalents of unreacted amine and unreacted acid functions on the nylon. M _w is the weight average molecular weight measured in Daltons.

Table 1 shows composites of four different types of treated clay. The control using the non-ammonium-treated clay of the present invention was the same as the previous (i.e., comparative, except for the control, 3-C, which showed no change in tensile strength when compared to 1-C. When compared to a sample that does not contain clay (i.e., 2-C, 3-C,
(Comparing 4-C with 1-C, 6-C, 7-C, 8-C with 5-C) shows an overall decrease in tensile strength.

Work numbers 1-C to 4-C were operated with a ZSK twin screw extruder, and work numbers 5-C to 8-C were operated with an FCM mixer.

[0071]

[Table 4]

Table 2 shows more than 125 MERs with four different quaternary ammonium treatments.
7 shows a composite of clay with. The composite material was processed using a ZSK mixer. All controls show a decrease in tensile strength when compared to the previous (corresponding) sample without clay.

[0073]

[Table 5]

Table 3 shows composites prepared in an FCM mixer from 13 different quaternary ammonium treated clays. All composites except 35, 36 and 47 show an increase in tensile and flexural modulus without a decrease in tensile strength when compared to nylon without treated clay. However, 35, 36, 47
Considering the standard deviation of the samples, it is likely that the samples can provide tensile strengths equal to or higher than that of their control.

[0075]

[Table 6]

Table 4 shows composites processed from eight different quaternary ammonium treated clays in a ZSK twin screw extruder. All of the composites show an increase in tensile and flexural modulus with no decrease in tensile strength when compared to the sample without treated clay.

[0077]

[Table 7]

In Table 5, the following four nylon 6,6 products listed in the Nylon Type table,
A composite material was prepared using nylon d, nylon c, nylon b, and nylon h. The nylon is shown above in order of decreasing average molecular weight. Composite material is Z
Processed using a SK twin screw extruder.

All composites show an increase in tensile and flexural modulus without a decrease in tensile strength when compared to the sample without treated clay.

[0080]

[Table 8]

In Table 6, composite materials were prepared using a polymer blend of nylon h and nylon b. One blend, Example 85, was made by preparing a clay concentrate in nylon h such as Control Sample 83-C and then blending the concentrate with a second polymer such as b. A second blend, Example 86, was made by preparing a clay concentrate of nylon b and blending it with nylon h. These composites were processed using a ZSK twin screw extruder.

[0082]

[Table 9]

In Table 7, the treated clay and polymer concentrates other than polyamide are shown as nylon h
Let down or dilute. The control is a mixture of the polymer alone and nylon h.

[0084]

[Table 10]

The runs in Table 8 have varied feed points operating with clay treated with nylon. The clay was fed at the mouth of the ZSK twin screw extruder or downstream of the mouth. The nylon used is a copolymer of 80% nylon 6,6 and 20% nylon 6.

[0086]

[Table 11]

In Table 9, composites are prepared from silicates treated with eight different quaternary ammonium / ammonium blends. The composites are processed using a ZSK twin screw extruder. Taking into account the standard deviation of tensile strength measurements, all samples show an increase in tensile and flexural modulus without a decrease in tensile strength. Samples 125 through 135 show the effect of changing the nylon type.

[0088]

[Table 12]

In Table 10, composites were prepared from 6 different tertiary ammonium treated silicates. The composites are processed using a ZSK twin screw extruder. Considering the effect of the standard deviation of tensile strength measurements, all samples show an increase in tensile and flexural modulus without a decrease in tensile strength.

[0090]

[Table 13]

In Table 11, samples 147, 150, 152, 154, 156 are solid state polymerized. Shows dramatic improvements in tensile strength and elongation.

[0092]

[Table 14]

In-situ Polymerization of Nylon Nanocomposites Description of Method: In-situ polymerization states that improved clay dispersion and enhanced interfacial strength with nylon covering silicates is obtained by melt mixing. I have great hope. Efficient modulus strengthening of over 20% increase
It has been found in nanocomposites containing only 0.1 wt% nanosilicate. Silane may be added to the reactor feed to improve interfacial bonding in the final nanocomposite.

The polyamide nanocomposite composition comprises forming an aqueous mixture of a treated silicate material and a polyamide monomer, treating the mixture to polymerize the polyamide monomer, and a polyamide nanocomposite composition. Forming at least about 50% of the silicate material to form an article.

In certain embodiments, the layered silicates (montmorillonite, saponite, hectorite, laponite) and the chain silicates (sepiolite) are treated with a salt solution of hexamethylene adipamide (HMA) nylon 6,6 prior to polymerization. It can be incorporated into nylon 6,6 and nylon 6,6 / 6 copolymers by exfoliating and dispersing the clay therein. Copolymers of nylon 6,6 / 6 can be produced by including a component of ε-caprolactam in the monomer feed. This method is suitable for laboratory scale and pilot (250 lb (1
13 kg)) Proven in a scale autoclave.

In another embodiment directed to the preparation of the copolymer, the silicate may be predispersed in the caprolactam component before being added to the salt solution. Alternatively, a concentrate may be added in a caprolactam solution of nylon 6 or its precursor, preferably a peptizer, for later addition into the polymerization mixture of nylon 6,6, to make a concentrate. A low molecular weight liquid polyamide can be used as a carrier for the nanoclay. Concentrates of nanoclays exfoliated by high shear homogenization in these carriers can later be added to the nylon 6,6 polymerization cycle after removal of the aqueous ionic environment.

[0097]   The following factors may affect work performance.

A. Use of clay pre-dispersed in water prior to introduction to the polymerization mixture or wet undried clay b. Use of high shear ultrasonic energy or Venturi cavitation flow to exfoliate laminated clay prior to polymerization c. Salt concentration d. pH e. Diamine / acid ratio in HMA salt solution f. Ion exchange of cations on the surface to modify the hydrophobicity and reactivity of clay or the physical interaction of nylon with the polymer matrix g. Clay concentration h. Type of silicate i. Molecular weight of nylon at the time of adding clay to polymerization j. Nylon polymer / copolymer composition

This work was done with a “diamine spike”, ie to stop the acidification due to the clay or its treatment, and to compensate for the loss of HMD due to evaporation during the polymerization cycle in the mixture of hexamethylenediamine ( It may be preferable to work with a higher molar concentration of HMD) than adipic acid. The resulting high viscosity of the polymerized melt indicates that a large molecular weight was established in the polymer matrix.

Silicate Materials Certain mineral types are preferred for in situ polymerization processes at various points in the reaction cycle and are commercially available from SCP under the tradename Laponite®. Examples thereof include synthetic laponite, hectorite, sepiolite, saponite, and montmorillonite. It has been found preferable to first obtain a good dispersion in water of the silicate layer which has been peeled off before contacting with the salt solution. In this regard, it may be useful to start with an undried aqueous dispersion or suspension rather than a dry silicate. Alternatively, the dried silicate may be hydrated before it participates in the polymerization process. The silicates can be dispersed by high shear homogenization or by cavitation generated by ultrasonics or passing the aqueous suspension through a Venturi tube or by other methods known in the art.

The silicate material can be organically modified to create a stronger interface with the nylon matrix of the final nanocomposite. Such organoclays are more hydrophobic than untreated minerals and are therefore in water or nylon 6,
A stable colloidal dispersion may not form in the salt solution of 6. However, as in the melt-mixing method of the previous patent application, the polymer must penetrate between the layered clay structures later in the polymerization cycle after the aqueous phase has been largely removed by evaporation. You can On the contrary, its low molecular weight should enhance the rate of infiltration during, which is the more complete state of delamination and consequently the thickness obtained by direct melt mixing with the prepolymerized nylon resin. The smaller particles of the lead to the strengthening of the final composite.

Non-Ionic State In embodiments designed to avoid ionic environments altogether, the silicate material is added later in the polymerization cycle after the salt has been converted to the oligomer or lower molecular weight polymer. An alternative approach to avoid the effects of ions is to start the process with molten anhydrous salt instead of salt solution.

Peptizer In order to prevent gelation, the concentration of other minerals is preferably limited to 2% or 4%. Higher concentrations up to about twice this limit may be possible when a peptizer is also present in the mixture. They contain phosphate ions which can delay the development of structures in aqueous suspension. Phosphate also acts as a pH controlling buffer, which is desirable to achieve a high degree of dispersion of the clay.

Example Southern Clay Product, Gonzales, TX
s, Inc. 4 types of clays, Clayton type AF, APA, and mineral colloids BP and MO obtained from, in water, 70% solution of caprolactam in water, and 50% aqueous solution of hexamethylene adipamide (HMA), At 1%, a Dispermat mixer was used to disperse by running at 50 rpm for 60 seconds. Of these four clays, only the slightly BP dispersion in water was stable. High shear mixing is preferred. The Omni mixer is an example of a commercially available machine that provides high shear mixing.

It has been found that treatment of clay with aminolauric acid provides improved stability to colloidal suspensions of clay in salt solution. In fact, 4% aminolauric acid-treated montmorillonite, a macroscopically uniform product, was polymerized in nylon 6,6 in a laboratory autoclave. However, transmission electron microscopy (TEM) and wide-angle X-ray scattering (WAXS) revealed that the silicates of this composite material were not well exfoliated. The mechanical properties of injection molded specimens were not enhanced by the presence of clay.

Tallow bases (eg dimethyl dihydrogen tallow ammonium (2M2HT))
Foaming was observed in the tube of in-situ polymerization in a laboratory autoclave using the above-mentioned organoclay, but untreated (untreated) sodium and calcium montmorillonite did not exfoliate according to the clamp seen under the optical microscope. It was It was found that the use of the tertiary ammonium silicate treatment resulted in less foaming than the use of the quaternary ammonium silicate.

Nylon 6 / nylon 6,6 97.5 / 2.5 copolymer 4% by weight of 1
Polymerized in the presence of organo-montmorillonite 2-aminolaurate. The product exhibited significantly enhanced toughness and ductility over nylon 6,6 homopolymer nanocomposites. Optical microscopy showed no residual micron-sized clay, suggesting a higher degree of delamination of the clay than that of the homopolymer described above. This was confirmed with a transmission electron microscope (TEM). The injection-molded product of this sample had high properties, and showed a high strengthening effect of 25% increase in tensile modulus and 50% increase in yield strength with only about 1% by volume of silicate.

Alkoxy-modified organoclays containing more polar ammonium ions synthesized from alkoxy-functional Jeffamines are
It was observed to produce a more stable colloidal suspension in the MA / caprolactam mixed solution. In-situ polymerization was performed using ethoxy modified montmorillonite with good results. Initially, the temperature was kept low (<260 ° C) to protect the clay coating from degradation. Small test tube size polymerization
In a reactor manufactured by r), polymerization of the treated montmorillonite over the ammonium cations was carried out without stirring for the entire ethylene oxide / propylene oxide sequence range. Measurements by WAXS showed polymer infiltration into the silicate structure to the same extent as the samples prepared with stirring in a lab autoclave. The coating composition has a nylon 6,6 content, without impeding penetration into the silicate,
It made it possible to raise by 12%.

One of the propylene oxide quats produced a particularly stable colloidal suspension of a 50/50 mixture of nylon 6,6 salt solution and caprolactam, which did not phase separate at room temperature for several days. It was In contrast, the untreated sodium-montmorillonite suspension was found to be unstable at room temperature over a range of HMA / caprolactam mixed compositions. However, Southern Clay Product
ts, Inc. Gelwhite (Gelwhite) untreated C supplied by
In-situ polymerization of straight nylon 6 nanocomposite from a caprolactam solution containing a-montmorillonite produces a smooth stream concentrate and later letdown to nylon 6,6 to form a blended nanocomposite. I was able to.

Gelwhite L nanocomposite in nylon 6, prepared in a laboratory autoclave, at a concentration of 5%, 10%, 15%, was applied to a salt solution of hexamethylene adipamide before polymerization of nylon 6,6. It was let down to nylon 6,6 by adding it inside. The fibers of the resulting blend were clear and smooth, showing no clumps of clay, but no improvement in physical properties was observed.

Hydration of Silicates When montmorillonite is fully hydrated, whether it is a undried slurry or by first completely suspending dry clay in water, it is It was found to form a more stable colloidal suspension in methylene adipamide salt solution. The following types, gel white H, gel white L (Ca-montmorillonite exchanged with sodium), mineral colloid BP (untreated N)
a-montmorillonite), poly (propylene oxide) -treated montmorillonite,
It was found that the hydroxy-terminated poly (ethylene oxide / propylene oxide) copolymer treated montmorillonite produced a stable 3% colloidal suspension in water after high shear mixing with an Omni homogenizer. 72 hours after adding a solution of the salt in the water slurry in an amount corresponding to 4% clay in the final nanocomposite, of the following types: gel white H and L, mineral colloid BP and polyether organoclay. Some remained in suspension. The other slurries were stable for at least 1 hour. It was also found that none of the clays not hydrated in water became a suspension when the nylon salt was added.

Several suspensions of the following clays made by the above technique: Gel White H and L, Mineral Colloid BP and Polyether Organoclay were
Polymerization was then carried out in a test tube using a Pearl reactor without mixing. However, the d-spacing of the silicate layer of the resulting nanocomposite as measured by WAXS is
It was still low (13.9Å to 14.3Å), indicating low polymer ingress, at least in some clays. However, the spacing is greater than that seen with the as-received mineral colloid BP, Na-montmorillonite. The addition of carboxymethyl cellulose (CMC) was investigated to keep the clay surface separate until the low molecular weight polymer was formed.

Nylon 6 Example A nylon 6 nanocomposite was prepared using a modified nylon 6,6 2 hour batch polymerization cycle to include Ca-montmorillonite, Na-montmorillonite, synthetic hectorite laponite RD, attapulgite. Prepared in situ from an aqueous solution of caprolactam containing a range of untreated nanoclays. Laponite appeared to disperse most easily and showed no peaks in the WAXS spectrum of the resulting nanocomposite. The relative viscosity (RV) of the resulting nanocomposite was comparable to the control standard without clay, its transparency indicating good dispersion of the clay. An increase in recrystallization temperature of 4-9 ° C relative to the control standard indicates that the nanoparticles modify the crystal structure of the nylon matrix like a nucleating agent.

[0114]

[Table 15]

Therefore, it can be seen that the presence of silicate does not seem to affect the polymerization of nylon. Tensile test data for a sample of nylon 6 nanocomposite film prepared by pressing at elevated temperature from an autoclave between slabs shows that by increasing the concentration of Gel White H untreated Ca-montmorillonite,
It shows that tensile strength and elongation are somewhat reduced, but overall stiffness is increased. The modulus of the composite made with mineral colloid BP untreated Na-montmorillonite was found to be significantly higher (40%) than any of the other tested clays.

[0116]

[Table 16]

As an additional operation, the above experiment was repeated with 1% and 2.5% minerals with the addition of Laponite B minerals. Addition of a tetrasodium pyrophosphate (TSPP) peptizer to the Gel White H sample during homogenization helped form the dispersion. The resulting fiber was matte compared to the other candidates. 1% of all
The nanocomposite demonstrated a recrystallization temperature increase of 10 ° C.

Experiments were conducted on the lamination silicate infiltration of low molecular weight fused nylon into untreated Ca-montmorillonite.

Nylon 6 nanocomposite fibers with 2.5% Laponite RD silicate spun from a polymerization autoclave showed some electrical conductivity in high voltage tests. At the 5% and 10% concentrations, the melt viscosity was so high that the nanocomposite melt could not be removed from the autoclave.

Further mechanical data were obtained for nylon 6 fibers. Gel White L and Laponite RD are preferred over Mineral Colloid BP, Gel White H, Laponite B, and Attapulgite to improve modulus without loss of tenacity and elongation. Both spun and drawn yarns were bright and had no humps.

[0121]

[Table 17]

All clay types showed a nucleating effect. The clay was pre-dispersed in 70% caprolactam solution and the above experiment was repeated in part with 0.5% and 1.0% clay loading. The fourth cycle of the standard nylon 6,6 polymerization cycle is 3
It was extended from 0 minutes to 60 minutes.

[0123]

[Table 18]

These nanoclays produce some tenacity at 0.5% levels, while producing high modulus at 0.5% and 1.0% levels. They also prove to be effective nucleating agents for nylon 6. However, they also produced high levels of gels with HPLC fluorescence numbers around 100 ppm compared to 0-1 ppm for the nylon control.

Nylon 6,6 Examples Nylon 6,6 nanocomposites are commercially available from Nylon Plastics Hand.
book "(Melvin I. Kohan, Hanser Publishe
rs, Munich, 1995, pp. It can be polymerized by standard industrial means described in 17-23).

Gel White L is an in-situ polymerized product (Rohm and Haas Co.).
Tamol 850, a sodium polymethacrylate from nd Haas Company, is included to help disperse the clay) to a concentrate of up to 20% in nylon 6. These concentrates were extruded to give a water quench at the end of the third cycle of the standard polymerization process. The nanocomposite was comminuted and put back into the polymerization of nylon 6,6 either at the beginning of the process in a salt solution or later after the batch reached a temperature of 220 ° C. The latter technique produced a gel and neither enhanced the mechanical properties of the spun fiber.

Further, ion-exchanged C in which all Ca ²⁺ ions are exchanged for Na ⁺ ions
Polymerization was carried out by adding an undried slurry of a-montmorillonite containing polyacrylic acid as a peptizer into nylon 6,6 fiber at a concentration of 1%.
The yarn properties were not improved in any way. The melt viscosity was high, but spinning was possible. The appearance of the obtained yarn was smooth, but it was not glossy. Ca ²⁺ mining ore is attractive for fiber applications due to its white color. However, the aspect ratio of these exfoliated platelets is known to be lower than that of mined Na-montmorillonite.

If the clay dispersion in the salt solution of nylon 6,6 is aged for just a few hours, it begins to set. Polymerization of the dispersion aged for 1 day results in a low RV of nylon 6,6.

Silicate Concentrate Carrier Solution An alternative embodiment to the preparation of silicate / polyamide nanocomposites by in situ polymerization is a high concentration of pre-dispersed clay in a carrier for addition to a polymerization vessel (" As "concentrate"). For example, Gel White L
10% to 30% in an aqueous solution containing 25% of a 70% ε-caprolactam solution in water (based on the weight of the clay component) and 1% to 5% tamol 850 dispersant.
It was found that dispersion was possible at the concentration of. These dispersions remained stable at room temperature for over 3 weeks. Without the dispersant, Gel White L dispersion is 1
It results in a gel that cannot be cast at a concentration of 0% or higher. The advantage of using these clay concentrates is that they can be added to the reaction mixture later in the polymerization after the aqueous ionic environment has been largely eliminated by evaporation, thus reducing the opportunity for aggregation. . In this example, the dispersion was injected into a batch of nylon 6,6 polymerization when the temperature was in the range of 220 ° C to 235 ° C. The resulting fibers contained small clumps and fluoresced under UV light indicating the presence of gel. Therefore, the fiber properties were not improved over the nylon control.

In another example of the above technique, Laponite RD was combined with 70% caprolactam solution in water at a high concentration of 10% 3% Tamol® 850 together with 100% ethylene glycol (concentration Both could be dispersed (based on the weight of the clay).

According to WAXS data, tetrasodium pyrophosphate (TSPP) and carboxymethylcellulose (CMC) are not effective peptizers for stabilizing montmorillonite suspensions after addition to nylon 6,6 salt solution. I knew it wasn't.

Tamol® dispersant is a nanocomposite material of mineral colloid BP 1.5.
% To 2% was effective to polymerize in a nylon blend containing 20% to 30% of nylon 6 in nylon 6,6 made from an aqueous mixture of caprolactam and hexamethylene adipamide. However, the viscosity of the 2% nanocomposite was so high that it could not be extruded from the reactor. The copolymer composition is attractive because the low salt concentration reduces clay agglomeration, while the caprolactam component enhances penetration into the clay structure leading to more effective exfoliation.

Potassium tripolyphosphate (KTPP) has been found to be an effective peptizer for nanosilicates in salt solutions of nylon 6,6. It is also considered to suppress gel formation. The spun and drawn fibers prepared by later injecting the stabilized gel white slurry into a nylon 6,6 polymerization cycle were small chunks obtained by a routine procedure using TSPP and Tamol® 850 peptizer. Unlike a fluorescent gel, it was transparent and gel-free. The fiber containing 0.3% nanoclays retained its matrix properties.

[0134]

[Table 19]

Fibers containing 0.6% mineral colloid BP, 1% KTPP and a small amount of caprolactam based on clay weight were also transparent in appearance with only a few small lumps occurring.

Many of the quaternary ammonium halides, such as those used for organomontmorillonite, lack the thermal stability required to withstand the polymerization temperatures of nylon 6,6 from 280 ° C to 300 ° C. Lauryl-dimethyl-3-sulfopropyl betaine (Ralufon DL from Rascip Corp.), which has high temperature stability, has 7
When successfully infiltrated into Gelwhite L untreated Ca-montmorillonite at a 1% concentration in 0% caprolactam solution and injected later in the polymerization cycle of nylon 6,6,
At 0.3% mineral concentration, it produced gel-free nylon 6,6 fibers with excellent gloss along with good mechanical properties.

To avoid exposing 2% nanocomposites of mineral colloid BP, aminolauric acid and (2-ethylhexyldimethylhydrogenated tallow) modified montmorillonite to the ionic environment of the salt solution, the molten hexamethylene adipamide salt And low RV (9-10) nylon 6,6 polymer by infiltration. W
The AXS data show that the latter improves the infiltration of the polymer and approaches the complete unraveling of the clay structure.

Nylon 6,6 nanocomposite with 1% nanoclay was prepared from an undried aqueous suspension, except for Dry Gel White H, which had to be redispersed in water. The predispersion was introduced into the salt solution using an Omni homogenizer and then mixed under high shear for an additional 10 minutes.

[0139]

[Table 20]

All the above clays were obtained from SCP. The Ca-montmorillonite slurry was exchanged with sodium ions and an acrylic peptizer was mixed therein.

Samples 8515, 8517, 8520 were removed from the autoclave for polymerization due to the high viscosity suggesting significant clay exfoliation despite the presence of the WAXS residual peak at 14.4 Å. I couldn't push it. The large width of the peaks indicates that the deposition of the first flakes of clay reduced the thickness somewhat. Nylon 6,6 nanocomposite with 1% nanoclay from Na-montmorillonite undried slurry showed high reinforcing efficiency with 15% increase in tensile modulus. Sample 8522 was injection molded into a tensile test bar which, in the presence of a small amount of clay,
High efficiency enhancement from 435 kpsi (about 3.00 x 10 ⁶ kPa) to 500 k
It showed a 15% modulus increase to psi (about 3.45 x 10 < ⁶ > kPa).

The presence of clay does not appear to significantly affect the molecular weight of the polymer formed or its distribution. In sample number 8515, the presence of CMC reduced the molecular weight as expected.

Five mock test articles of carpet fiber and industrial tire cord fiber modified with 0.5% and 1.0% of Gel White L were used, 1 each for KTPP and Tamor 850 based on the weight of clay. Made in a small autoclave from 10% clay predispersed in a 70% aqueous solution of caprolactam containing 10%. The clay slurry was poured into polymerizing nylon 6,6 at 235 ° C during the second cycle of the process. Both concentration levels increased the 10% -20% modulus in the spun fiber, but this advantage was retained after drawing only in the carpet fiber at the lower concentration level. The tenacity and elongation of both types of spun and drawn fibers showed a slight decrease. Later, it was shown that it would be preferable to omit the tamol component in this particular formulation.

250 lbs (113k) with very low mineral concentrations with significant height nano-reinforcement
g) was achieved in injection molded articles of nylon 6,6 nanocomposite produced by in-situ polymerisation in batch. Laponite RD synthetic raw hectorites were loaded with 90 kpsi of raw nylon by incorporating a mineral content of only 0.072% by weight.
There is an increase in tensile modulus above about 0.62 × 10 ⁶ kPa) (20%), which means 10 times the maximum gain that can be predicted from the classical strengthening mechanism. Very small size micelles exhibiting nucleation could be detected in these nanocomposites by optical microscopy through orthogonal polarizers.

Untreated sepiolite of chain silicates has proven to be as effective as montmorillonite or hectorite in reinforcing nylon fibers by in situ polymerization. At a concentration of 0.1% it offers high drawability and enhanced mechanical properties. The following fiber properties were obtained at a draw ratio of 6.5 relative to the raw nylon control. Modulus 84: g / denier vs. 76 g / denier, tenacity:
10.2 g / denier vs 9.1 g / denier, elongation at break: 12.3% vs 10.
4%. The RV of the nylon matrix was comparable to the control of raw nylon.

Sepiolite (1%) increased the flexural modulus by 13% in laboratory autoclave polymerized nylon 6,6. However, 250 pounds (113 kg
) Autoclave, the sepiolite nanocomposite did not demonstrate significant improvement over the same nanocomposite as in the small scale experiments. Injection moldings containing 0.09% by weight untreated sepiolite showed lower toughening than the corresponding Laponite material. Tensile strength is still 11.1 kpsi to 12.0 kp compared to unreinforced nylon 6,6 control
increased significantly up to si. The increase in modulus was modest only 6%, while the elongation still reached 30% deformation. As with Laponite, the presence of sepiolite minerals during the polymerization of nylon had no effect on the nylon polymer and an RV of 42 and acid / amine end group concentrations of 72 / 52.4 were registered. One of the advantages of sepiolite is that it can be directly and efficiently dispersed in a salt solution of HMA without having to make a predispersion in water.

Silanes, especially aminopropyltriethoxysilanes, can be incorporated into polyamides such as nylon 6,6 by addition to nanoclays to the salt solution prior to polymerization. At low amounts (0.12% to 0.25%), no significant benefit was provided to the resulting nanocomposite, which also contained only low amounts of nanoclays (0.1%). However, high concentrations of both silane (up to 0.5%) and nanoclays (up to 2%) used in injection molding serve to increase the ductility of the nanocomposite. Obviously, the interfacial strengthening due to silanes in conventional melt-mixing systems can also be effective by in-situ polymerization. On the other hand, in the absence of the silicate, the silane alone showed some of its own reinforcing potential in the drawn fiber.

Reinforcement by high aspect ratio is generally achieved by in situ polymerized nylon 6,
Produces high properties in fibers drawn from 6 nanocomposites. Therefore, montmorillonite and hectorite are more effective than Laponite B, which in turn is more effective than Laponite RD.

By incorporating the nanoclay during the polymerization, the crystallinity is slightly increased,
The recrystallization temperature generally increases (up to 8 ° C). Sepiolite, saponite, and to a lesser extent, hectorite is the most effective nanosilicate nucleating agent.

Further examples of fibers spun and drawn from pilot plant scale in situ polymerized nylon 6,6 nanocomposites include those untreated with montmorillonite, hectorite, laponite B and ion-exchanged with ammonium cations. Including both. Only 0.1 by weight, which is important for tire cord applications
A 15% increase in modulus and tenacity was achieved with a 30% increase in creep resistance at low concentrations of minerals. 3 with increasing tenacity up to 10%
A higher modulus increase to 0% was observed on a bench scale.

Of particular interest was the stretching of 0.1% untreated hectorite nanocomposite 16.
The 2% secant rate of the 6 g / denier carpet yarn was 44% higher than the 11.7 g / denier control yarn made in the same test and drawn to the same denier. The elongation at break was comparable to the control, while the tenacity was slightly higher. The good performance of this nanocomposite may be due to the predispersion of the silicate in the small amount of caprolactam component of the formulation.

Dihydroxycetyl octadecyl ammonium is a preferred cation for ion exchange on phyllosilicate minerals for in situ polymerization of nylon 6,6. The in-situ polymerized nanocomposite with either 0.2% and 0.4% montmorillonite previously treated with this cation showed improved appearance retention in carpet walk tests. Due to their low hydrophilicity, organoclays are predispersed at concentrations up to 5% directly in solutions of nylon salts rather than in pure water, as is preferred for untreated minerals.

Nylon 6,6 which can occur at higher silicate concentrations (eg 2%)
Some hindrance to the polymerization can be overcome by extending the reactor residence time in the finishing cycle by about 30%.

The increased modulus with slightly decreasing ductility is an indication of a better dispersion of nanoparticles provided by the ultrasonic energy initially applied to the clay slurry.

The ideal mineral concentration for fiber spinning is about 1% or less by weight, preferably about 0.1%.
% To about 0.2%. Upon injection molding application, high injection molded product properties were found for a silicate content of 1.5%. That is, tensile strength: 91 MPa
, Modulus: 3.4 GPa, ultimate elongation: 47%, whereas standard raw nylon 6,6 homopolymers are 80 MPa, 3.0 GPa, respectively.
Displayed 60%.

Fiber Applications Fiber applications seek to approach the advantages gained by in situ polymerization from the lower modulus for plastic molding applications. To that end, it may be used at low clay concentration levels where nanoscale interactions play a major role. In the process of spinning and drawing fibers, higher levels of orientation can occur than in injection molding. The use of high drawing temperatures further improves the performance of the nanocomposite yarn by controlling the molecular deformation. Gloss, smoothness (no small lumps), opacity are indicators of the particle size remaining in the clay contained in the spun and drawn fibers.

Solid State Polymerization of In Situ Polymerized Nanocomposite Solid state polymerization was performed at 200 ° C. for 1.5 hours using in situ polymerized nylon 6,6 with four different silicates. The molecular weight was measured before and after solid phase polymerization. The nanocomposite sample showed an increase in molecular weight similar to raw nylon 6,6.

[0158]

[Table 21]

Comparison of Compositions Obtained by In Situ Polymerization vs. Compositions Obtained by Melt Mixing A fully hydrated, undried slurry of mineral colloid BP (Na-montmorillonite) was treated with 50% nylon 6,6 salt solution. In addition, homogenize, polymerize, wt%
In this way, 1.0% and 1.25% nanocomposite materials were produced. The nanocomposite material was injection molded and tensile tested according to ASTM method D-638. A nanocomposite material for comparison is a similar montmorillonite pretreated with an ammonium compound to enable penetration and exfoliation by the nylon melt, as taught in the patents previously filed by the inventors. And a twin screw extruder on a twin screw extruder. The two treatments that produced nearly identical results were the dimethyldihydrogen tallow ammonium and the dimethyl (ethylhexyl) hydrogen tallow ammonium cations. The tensile modulus data plotted in relation to the mineral content of the nanocomposite show that the in-situ polymerized composition has higher performance at the same loading as the comparative material made by melt mixing. (Figure). Both are superior to traditional composites in which nanoparticles are packed with non-exfoliated kaolin clay.

[Brief description of drawings]

[Figure 1]   The relationship between the mineral content and the tensile elastic modulus in the nanocomposite material is shown.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE), OA (BF, BJ , CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, K E, LS, MW, SD, SL, SZ, UG, ZW), E A (AM, AZ, BY, KG, KZ, MD, RU, TJ , TM), AE, AL, AM, AT, AU, AZ, BA , BB, BG, BR, BY, CA, CH, CN, CR, CU, CZ, DE, DK, DM, EE, ES, FI, G B, GD, GE, GH, GM, HR, HU, ID, IL , IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, M G, MK, MN, MW, MX, NO, NZ, PL, PT , RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, V N, YU, ZA, ZW (72) Inventor Lysetsk, Bruce A.             32533, Kan, Florida, United States             Tonment, Broken Arrow Ray             N940 (72) Inventor Middleton, Jiyoung Shee             35244, Bar, Alabama, United States             Mingham, Rasset Hill 1788 F-term (reference) 4J001 DA01 DB01 DB03 EA06 EA08                       EA14 EB02 EC02 EE18 GA12                       JA01 JA02 JA04 JA12 JA15                       JB21 JB23                 4J002 CL001 CL031 CL051 DF006                       DJ006 FD016 GM00

Claims (23)

[Claims] 1. A method for preparing a polyamide nanocomposite composition, the method comprising forming an aqueous mixture of a silicate material and a polyamide monomer, and
A method comprising treating the mixture to polymerize polyamide monomers to form a polyamide nanocomposite composition. 2. The polyamide is nylon 6, nylon 6,6, nylon 4,
The method according to claim 1, which is 6, nylon 6,9, nylon 6,10, nylon 6,12, nylon 11, nylon 12, amorphous nylon, aromatic nylon, or a copolymer thereof. 3. The method according to claim 1, wherein the polyamide is a copolymer of nylon 6,6 and nylon 6. 4. The method according to claim 1, wherein the monomer is hexamethylene adipamide, ε-caprolactam, lauryllactam, ε-caprolactone, or lauryl lactone. 5. The method of claim 1, wherein the monomer is hexamethylene adipamide. 6. The method according to claim 1, wherein the monomer is a mixture of hexamethylene adipamide and ε-caprolactam. 7. The method of claim 1, wherein the silicate material is laponite, hectorite, sepiolite, saponite, attapulgite or montmorillonite. 8. The method of claim 1, wherein the silicate material is added in a fully hydrated form, a non-dried slurry form, an aqueous slurry form, or an aqueous suspension form. 9. The method of claim 1, wherein the silicate material is a colloidal dispersion of silicate material that is fully hydrated and exfoliated in water. 10. The method of claim 1, wherein the silicate material is an organically treated silicate. 11. The method of claim 1, wherein the mixture further comprises a dispersant. 12. The dispersant is sodium polymethacrylate.
The method according to 1. 13. The method of claim 1, wherein the mixture further comprises silane. 14. The method of claim 13, wherein the silane is aminopropyltriethoxysilane. 15. The method of claim 1, wherein the concentration of silicate material in the polyamide nanocomposite composition is less than about 2% by weight. 16. The method of claim 1, wherein the concentration of silicate material in the polyamide nanocomposite composition is less than about 1% by weight. 17. The method of claim 1, wherein the concentration of silicate material in the polyamide nanocomposite composition is between about 0.05% and about 0.2% by weight. 18. The method of claim 1, wherein the mixture has a higher hexamethylenediamine molar concentration than adipic acid. 19. The method of claim 1, wherein prior to the polymerizing step, the mixture further comprises an oligomer of polyamide monomer or a low molecular weight polymer of polyamide monomer. 20. The method of claim 1, further comprising dissociating at least about 50% of the silicate material. 21. The method of claim 20, wherein the silicate material is dissociated by mechanical devices, pressure changes, ultrasonic waves, stirrers, or high shear homogenizers. 22. A polyamide nanocomposite composition prepared by the method of claim 1. 23. A polyamide nanocomposite composition comprising a polyamide and a silicate material, wherein the polyamide nanocomposite has a higher tensile modulus than the tensile modulus of the composition containing the components prepared by melt insertion at the same concentration. Composite material composition.