WO2011066495A1

WO2011066495A1 - Polyamide alloy and its usage

Info

Publication number: WO2011066495A1
Application number: PCT/US2010/058159
Authority: WO
Inventors: Ying Lei; Chang Liu; Mason Zhao; David D. Zhang
Original assignee: Liu Chang International Co Ltd; EI Du Pont de Nemours and Co
Current assignee: Liu Chang International Co Ltd; EIDP Inc
Priority date: 2009-11-30
Filing date: 2010-11-29
Publication date: 2011-06-03
Anticipated expiration: 2012-05-30
Also published as: CN102079867A; CN102079867B

Abstract

Disclosed is a polyamide alloy, which comprises (a) 50-80wt% of at least one aliphatic polyamide and (b) 20-50wt% of vinyl copolymer blend comprising at least two of the following components: (i) graft-modified ethylene-olefin copolymer, (ii) graft-modified ethylene propylene rubber, and (iii) styrene rubber.

Description

POLYAMIDE ALLOY AND ITS USAGE

The invention relates to a polyamide alloy having excellent elastic property and dynamic mechanics property (high energy recovery), as well as outstanding wear resistance and low temperature flexibility. The polyamide alloy can be prepared by a simple process with low cost. The invention also relates to the use of the polyamide alloy in the manufacture of elastic articles.

Background of the Invention

The poly ether-amide block copolymer is a copolymer with A-B alternating structure. In a regular poly ether-amide block copolymer, wherein the hard segment can include polyamide 12 and the soft segment B can include poly 1 ,4-diol. The existing polyamide has excellent properties (such as good wear resistance and low temperature flexibility), and is widely used in the manufacture of sports shoes, buffer cushion against falling. It can also be used as molding thermoplastic elastomer in the manufacture of medical device parts, sport goods parts, automobile and mechanical tool parts, and electronic product parts, etc.

For example, in the auto industry, the existing poly ether-amide block copolymer can be used for the manufacture of sun visor clip, locker compound injection molding, windshield cleaning tubes, auto radio antenna, and antenna base, etc.

In sports equipment, the existing poly ether-amide block copolymer can be used for the manufacture of hiking shoes, sports shoes, sports watch shell, sports shoes spike, shoe sole, tennis racket handle, etc.

Using sports shoes as an example, the shore D hardness (ASTM D 2240) of the poly ether-amide block copolymer used for the manufacture of sports shoes is usually 60-66D; the density (ASTM D 297) is usually 0.98-1 .02; the tensile strength (ASTM D 412) is usually 380kg/cm²; the elongation at breaking point (ASTM D 412) is usually 300%; the tear strength (ASTM D 624) is usually 177kg/cm; the flexibility (sports shoes common industry standard) at -6°C is usually 150,000 times; Akron wear resistance (J IS K

6264-2:2005) is usually 0.04cc loss.

Although the conventional poly ether-amide block copolymer used in the

manufacture of sports shoes has excellent properties, this kind of poly ether-amide block copolymer is obtained in the reactor by the copolymerization, requiring expensive polymerization equipment and resulting in high manufacturing costs.

Because of the shortcomings of the existing poly ether-amide block copolymer, there are various proposals in the field using modified nylon to replace poly ether-amide block copolymer. But the existing modified nylons cannot achieve both good wear resistance and low temperature flexibility concurrently, which largely differ from the poly ether-amide block copolymer.

Therefore, there is an unmet need in the field to develop further modified nylon having better properties than existing poly ether-amide block copolymer, using simply manufacture process.

Summary of the Invention

The invention provides a polyamide alloy, which not only has similar properties to existing poly ether-amide block copolymer (such as having both good wear resistance and low temperature flexibility), but also can be prepared by a simple process without using expensive polymerization equipment, which results in the great reduction in final product costs. In addition, the polyamide alloy preferably has better tear resistance and energy recovery than the existing poly ether-amide block copolymer.

The invention further provides a manufacturing method for the polyamide alloy. The polyamide alloy amy comprise:

(a) 50-80wt% of at least one aliphatic polyamide, and

(b) 20-50wt% of vinyl copolymer blend, wherein the vinyl copolymer blend comprises at least two of the following components: (i) graft-modified ethylene-olefin copolymer, (ii) graft-modified ethylene propylene rubber, and (iii) styrene rubber;

Based on the weight of the pre-g raft-modified ethylene-olefin copolymer, the graft-modified ethylene-olefin copolymer may comprise 60-92wt% of the monomer units from ethylene and 8-40wt% of one or more monomer units from C -i₀ olefins;

Based on the weight of the pre-g raft-modified ethylene propylene rubber, the graft-modified ethylene propylene rubber may comprise 45-80wt% of the monomer units from the ethylene, 20-55wt% of the monomer units from the propylene, and 0-20wt% of one or more monomer units from C_5-io non-conjugated diene.

The invention also provides a method for the polyamide alloy comprising (a) providing 50-80wt% of at least one aliphatic polyamide;

(b) providing 20-50wt% of vinyl copolymer blend, wherein the vinyl copolymer blend comprises at least two of the following components: (i) graft-modified

ethylene-olefin copolymer, (ii) graft-modified ethylene propylene rubber, and (iii) styrene rubber; and

(c) mixing to prepare the polyamide alloy,

Wherein the graft-modified ethylene-olefin copolymer and graft-modified ethylene propylene rubber are described as above.

Brief Description of the Figures

Figure 1 is the dynamic mechanics curves comparing the polyamide alloy sample described herein with the control sample of prior art.

Figure 2 is the energy recovery comparative diagram at different temperatures between the polyamide alloy described herein and the control sample of prior art.

Detailed Description of the Invention

The inventors discovered that when a single type of graft-modified elastomer or rubber vinyl copolymer is added to the aliphatic polyamide, the improved low temperature flexibility and wear resistance of the final polyamide alloy cannot be achieved in spite of the improvement in impact property. The final polyamide alloy can have better low temperature flexibility and wear resistance only when using compound graft-modified vinyl copolymer. The inventors also discovered that the polyamide alloy also has improved tear resistance and energy recovery.

1 . Aliphatic polyamide

The polyamide alloy described herein comprises at least one aliphatic polyamide. The aliphatic polyamide can be any aliphatic polyamide known in the field.

The non-limiting examples of the aliphatic polyamide are:

(i) The condensation producst of one or more amino acids;

The suitable non-limiting examples of the amino acids are a, ω-amino acids such as amino hexanoic acid, 7-amino heptanoic acid, 1 1 -amino-undocanic acid,

12-amino-dodecanoic acid, and 4-(aminomethyl)benzoic acid, etc.

(ii) The condensation products of one or more lactams;

The suitable non-limiting examples of lactams are β, β-dimethyl propyl lactam, a, α-dimethyl propyl lactam, δ-volerolactam, ε-caprolactam, heptyl lactam, octyl lactam, and dodecyl lactam, etc.

(iii) The condensation product of one or more amino acids with one or more lactams; The suitable non-limiting examples of amino acids and lactams are described as above;

(iv) The condensation products of one or more diamines with one or more diacids, or their salts;

The suitable non-limiting examples of the diamines are 1 ,6-hexane-diamine,

1 .5- pentane-diamine, 1 ,12-dodecane-diamine, 1 ,4-butane-diamine, 1 ,8-octane-diamine, 1 ,10-decane-diamine, 1 -methyl-1 ,4-butane-diamine, 2, 2,4-trimethyl-1 ,6-hexane-diamine, isophorone diamine, 2-methyl-1 ,5-pentane-diamine, 4,4'-diaminodicyclohexyl-methane, bis (3- methyl -4-amino cyclohexyl) methane, bis(p-aminocyclohexyl) methane, trimethyl-1 ,6-hexane-diamine and 5,6-dimethyl-pentane-1 ,6-diamine, etc.

The suitable non-limiting examples of diacids are: hexanedioic acid, nonanedioic acid, butanedioic acid, cyclohexanedioic acid, octanedioic acid, decanedioic acid, and dodecandioic acid, etc.

(v) The condensation products of one or more lactams, one or more diamines, and one or more diacids, or their salts;

The suitable non-limiting examples of lactams, diamines, and diacids are stated as above; and

(vi) The condensation products of one or more amino acids, one or more diamines, and one or more diacids, or their salts.

The suitable non-limiting examples of amino acids, diamines, and diacids are stated as above.

The non-limiting examples of aliphatic polyamide include the condensation product

(PA-6/12) of caprolactam and dodecane-12-lactam; the condensation product (PA-6/6,6) of caprolactam, hexanedioic acid and 1 ,6-hexane-diamine; the condensation product (PA-6/12/6,6) of caprolactam, dodecane-12-lactam, hexanedioic acid and

1 .6- hexane-diamine; the condensation product (PA-6/6, 9/1 1/12) of caprolactam, dodecane-12-lactam, 1 1 -amino-undocanic acid, nonanedioic acid and

1 ,6-hexane-diamine; the condensation product (PA-6/6, 6/1 1/12) of caprolactam, dodecane-12-lactam, 1 1 -amino-undocanic acid, hexanedioic acid and

1 ,6-hexane-diamine; and the condensation product (PA-6/6, 9/12) of

dodecane-12-lactam, nonanedioic acid and 1 ,6-hexane-diamine. The blend of the aliphatic polyamide can also be used for the polyamide alloy described herein, such as the blend of two or more of above aliphatic polyamides in any ratio.

The number average molar mass M_n of the suitable aliphatic polyamide in the polyamide alloy described herein is usually larger than or equal to 12000, preferably 15000-50000. Its weight average molar mass M_w is usually larger than 24000, preferably 30000-100000. Its inherent viscosity is usually larger than 0.9 ( 5x10^"3g/^crT|3 m-cresol sample was measured at 25°C according to ISO 1628-1 ).

The suitable aliphatic polyamide used in the polyamide alloy can be purchased from the market, for example, Zytel^® 7301 NC 010 (Nylon 6), Zytel^® 101 NC 010 (Nylon 66) or Herox^® 1010 (Nylon 1010), purchased from U.S. Du Pont & Co. Besides, it can be UBS 1015B (Nylon 6) purchased from Japan Ube Industries, Ltd.

In a preferred example herein, a long chain aliphatic nylon was used as the aliphatic polyamide, as the long chain aliphatic nylon makes better contribution for the yellowing resistance of the final polyamide alloy. The examples of the long chain aliphatic nylon are poly(decyldiamide decyldiamine) (Nylon 1010), polyundecylamide (Nylon 11 ),

polydodecylamide (Nylon 12), poly(dodecyldiamide hexyldiamine) (Nylon 612), or the combinations of the two or more thereof in any ratio, etc.

2. Vinyl copolymer blend

The polyamide alloy described herein also comprises a vinyl copolymer blend. The vinyl copolymer blend comprises at least two of the following components: (i)

graft-modified ethylene-olefin copolymer, (ii) graft-modified ethylene propylene rubber, and (iii) styrene rubber.

(i). Graft-modified ethylene-olefin copolymer

The graft-modified ethylene-olefin copolymers suitable for the polyamide alloy herein come from elastomer type or rubber type ethylene-olefin copolymers (simplified as ethylene-olefin copolymer hereafter). The ethylene-olefin copolymers include monomer units from ethylene and one or more monomer units from C_4-io olefins.

The suitable non-limiting examples of C_4-io olefins are: C_4-io a-olefins such as 1 - butene, 1 -pentene, 1 -hexene, 1 -heptene and 1 -octene, and other olefins such as

2- heptene, 2-butene, 2-octene and 2-hexene, etc.

The ethylene-olefin copolymer can be a binary copolymer of ethylene and an olefin. The ethylene-olefin copolymer, on the premise of without changing its properties, may comprises one or more other monomer units to form ternary or multi- copolymer. In a preferred example herein, the other monomer is selected from C -i₀ a-olefins such as

1 - butene, 1 -pentene, 1 -hexene, 1 -heptene and 1 -octene, and other olefins such as

2- heptene, 2-butene, 2-octene and 2-hexene, etc.

Based on the total weight of the ethylene-olefin copolymer, the ethylene-olefin copolymer comprises 60-92wt% of the monomer units from ethylene, preferably

65-88wt%, more preferably 72-80wt%; 8-40wt% of the monomer units from C_4-io olefins, preferably 12-35wt%, more preferably 18-20wt%.

In a preferred example herein, the ethylene-olefin copolymer is selected from ethylene-octylene binary copolymer (ethylene-octylene elastomer). The raw rubber Mooney viscosity ML(1 +4)of the ethylene-octylene elastomer was measured at 125°C as 16-24.

The graft-modified ethylene-olefin copolymer refers to the above mentioned elastomer type or rubber type ethylene-olefin copolymers grafted with one or more acids, acid anhydrides or epoxy functional groups on its branches. The non-limiting examples of the functional groups are: glycidyl methacrylate, methacrylic acid, methacrylic anhydride, maleic acid, maleic anhydride, fumaric acid, itaconic acid, citric acid, allyl succinic acid, cyclohex-4-ene-1 ,2-dicarboxylic acid, 4-methyl-cyclohex-4-ene-1 ,2-dicarboxylic acid, bicycle[2.2.1 ]hept-5-ene-2,3-dicarboxylic acid, x-methyl-bicyclo

(2.2.1 )-hept-5-ene-2,3-dicarboxylic acid, itaconic anhydride, citric anhydride, allyl succinic anhydride, cyclohex-4-ene-1 ,2-dicarboxylic anhydride,

4-methyl-cyclohex-4-ene-1 ,2-dicarboxylic anhydride, bicycle [2.2.1 ]

hept-5-ene-2,3-dicarboxylic anhydride, and x-methyl-bicycle [2.2.1 ]

hept-5-ene-2,3-dicarboxylic anhydride. The grafting degree of the graft-modified ethylene-olefin copolymer is 0.01 -5wt%, preferably 0.1 -3wt%, more preferably 0.2-1wt%.

Various public known methods can be used to graft functional groups to the ethylene-olefin copolymers. For example, the mixture of ethylene-olefin copolymer and above functional groups can be heated to about 150-300°C to graft, at the presence or absence of solvents, with or without free radical initiators.

The suitable graft-modified ethylene-olefin copolymer used in the polyamide alloy can be purchased from the market, for example, Fusabond® 493D (a maleic anhydride grafted ethylene-octylene elastomer) purchased from U.S. Du Pont & Co.

(ii) graft-modified ethylene propylene rubber

The graft-modified ethylene propylene rubber suitable for the polyamide alloy described herein includes one or more monomer units not only from ethylene and propylene, but also from C_5-io non-conjugated diene. The suitable non-limiting examples of the C5-10 non-conjugated dienes are 1 ,4-pentadiene, 1 ,4-hexadiene, 1 ,5-hexadiene, 1 ,4-heptadiene, 1 ,5-heptadiene, 1 ,4-octadiene, 1 ,5-octadiene, etc. Besides, the ethylene propylene rubber, on the premise of without changing its properties, may comprise small amount of one or more other monomer units.

Based on the total weight of the ethylene propylene rubber, the ethylene propylene rubber comprises 45-80wt% of the monomer units from ethylene, preferably 45-78wt%, more preferably 45-75wt%; 20-55wt% of the monomer units from propylene, preferably 20-53wt%, more preferably 20-50wt%; 0-20wt% of the monomer units from C_5-io

non-conjugated diene, preferably 2-18wt%, more preferably 5-15wt%.

In a preferred example herein, the ethylene propylene rubber is selected from an ethylene-propylene-non-conjugated diene ternary copolymer (ternary ethylene propylene rubber EPDM). The ternary ethylene propylene rubber comprises 65-75wt% of ethylene monomer units, having raw rubber Mooney viscosity ML 1 +4 17.5-22.4, measured at 125°C, density 0.88, and crystallinity less than 30%.

The graft-modified ethylene propylene rubber refers to the above mentioned ethylene propylene rubber grafted with one or more acids, acid anhydrides or epoxy functional groups on its branches. The non-limiting examples of the functional group are: glycidyl methacrylate, methacrylic acid, methacrylic anhydride, maleic acid, maleic anhydride, fumaric acid, itaconic acid, citric acid, allyl succinic acid,

cyclohex-4-ene-1 ,2-dicarboxylic acid, 4-methyl-cyclohex-4-ene-1 ,2-dicarboxylic acid, bicycle [2.2.1 ] hept-5-ene-2,3-dicarboxylic acid, x-methyl-bicyclo

4-methyl-cyclohex-4-ene-1 ,2-dicarboxylic anhydride, bicycle [2.2.1 ] hept-5-ene-2,3-dicarboxylic anhydride, and x-methyl-bicycle [2.2.1 ]

hept-5-ene-2,3-dicarboxylic anhydride. The grafting degree of the graft-modified ethylene propylene rubber is 0.01 -5wt%, preferably 0.1 -3wt%, more preferably 0.2-1 wt%.

The suitable graft-modified ethylene propylene rubber used in the polyamide alloy can be purchased from the market, for example, Fusabond® 416D (a maleic anhydride grafted ternary ethylene propylene rubber) purchased from U.S. Du Pont & Co.

(iii) Styrene rubber

The suitable styrene rubber used in the polyamide alloy can be any known

Styrene/butadiene random copolymer or its modified copolymer with 50-90 mol% of styrene. The styrene/butadiene random copolymer can be prepared by solution polymerization or emulsion polymerization. The non-limiting examples are

styrene/butadiene rubber (SBR styrene-butadiene-rubber) and maleic anhydride modified styrene/butadiene rubber, etc.

In a preferred example herein, the raw rubber Mooney viscosity ML 1 +4 of the styrene rubber was measured at 100°C as 48-58.

The suitable styrene rubber used in the polyamide alloy can be purchased from the market, for example, SBR 1502 purchased from Germany BASF and PSBR (Powder SBR, 90% SBR 1502, 10% calcium carbonate, molecular weight 200,000-300,000) from Shangdong Gaoshi Scientific Industry & Trade., Ltd., etc.

3. Polyamide Alloy

Based on the total weight of the polyamide alloy, the aliphatic polyamide is present in an amount of 50-80wt%, preferably 55-75wt%, more preferably 60-70wt%. The vinyl copolymer blend is present in an amount of 20-50wt%, preferably 25-45wt%, more preferably 30-40wt%.

As shown in later examples, the polyamide alloy has not only good tear resistance, low temperature flexibility and wear resistance, but also better energy recovery compared to existing poly ether-amide block copolymer. Generally, the polyamide alloy has 165 N/mm or higher tear resistance, 0.04 or lower wear resistance. It can also pass -6°C, 150,000 times, 60° bending test or -20°C, 40,000 times, 90° bending test (Ross Flex

Testing).

4. Additive The polyamide alloy described herein may also comprise various conventional additives. The suitable examples of the additives are heat stabilizer, UV absorbers, nucleating agents, antistatic agent, lubricant, flame retardants, colorants, pigments, brightening agents, antioxidants, inorganic fillers, plasticizers, or the mixtures of two or more thereof .

There is no special restriction on the amount of additives added, depending on the particular usages. In a preferred example, based on the total weight of the polyamide alloy, 0-5wt%, preferably 0.1 -3wt%, more preferably 0.5-2.5wt% of additives are added.

The invention combines the aliphatic polyamide and compound vinyl copolymer blend to obtain a polyamide alloy having aliphatic polyamide as continuous phase and vinyl copolymer blend as dispersed phase. This alloy has equal or better low temperature flexibility and wear resistance than poly ether-amide block copolymer elastomer as well as better tear resistance than poly ether-amide block copolymer elastomer. Besides, the inventors have discovered that the polyamide alloy has better energy recovery than poly ether-amide block copolymer elastomer.

Manufacturing Method

The polyamide alloy can be obtained by blending extrusion using, for excample. twin-screw extruder. Besides this apparatus, the alloy can also be prepared by BUSS mixer, double roller mixing mill, BRABENDER mixer, etc. There is no special restriction on the the process condition of blending extrusion, depending on the usage of the final product.

In a preferred example, the process conditions of the blending extrusion is listed as below:

1 . Extrusion: all materials were fed through a feeder to an extruder (for example

Toshiba37 twin-screw extruder), plasticized, blended, extruded and granulated at temperature 240-260°C and controlled screw speed 300-350rpm.

2. Testing specimen preparation: select suitable molding according to testing requirements, plasticize the extruded granulators via injection molding machine, formed at temperature 240-260°C. The formed sprcimen can be tested according to actual situation.

Compared to the existing poly ether-amide block copolymer, the polyamide alloy has no need of special expensive equipment to make, resulting in the great reduction of manufacturing costs.

In addition, the polyamide alloy described herein has similar properties to existing poly ether-amide block copolymer resin (simplified as existing resin hereafter): its shore D hardness (ASTM D 2240) is 64-68D (the existing resin is 60-66D); its density (ASTM D 297) is 0.99-1 .01 (the existing resin is 0.98-1 .02); its tensile strength (ASTM D 412) is 333-373 (the existing resin is 380kg/cm²); its elongation at breaking point (ASTM D 412) is 159-190% (the existing resin is 300%); its tear strength (ASTM D 624) is 177-21 1 kg/cm (the existing resin is177kg/cm); its flexibility molding at 23°C is 548-801 MPa (the existing resin is 376 MPa); its flexibility molding at -20°C is 965-1061 MPa (the existing resin is 1234 MPa); its Akron wear resistance (JIS K 6264-2:2005) is 0.018-0.04cc loss (the existing resin is 0.04cc loss); and its flexibility molding at -6°C can reach the same level as the existing resin.

The following examples further illustrate the polyamide alloy.

Examples

The following products were used as raw materials in the following examples: UBE 1015B: PA6 produced by Japan Ube Industries, Ltd., its melting point was about 220°C;

Herox®1010: PA1010 produced by XingDa Du Pont & Co, LTD.; its melting point was about 205°C;

Fusabond® N493D: a maleic anhydride grafted ethylene-octylene elastomer) produced by U.S. Du Pont & Co.

Fusabond® E226D: a maleic anhydride grafted poly ethylene produced by U.S. Du Pont & Co.

Fusabond® N416D: a maleic anhydride grafted ternary ethylene propylene rubber (ethylene propylene non-conjugated diene copolymer produced by U.S. Du Pont & Co.

PSBR: Powder SBR, purchased from Shangdong Gaoshi Scientific Industry & Trade., Ltd.,

Pebax 7033: poly ether-amide block copolymer elastomer produced by Arkema;

Pebax 6333: poly ether-amide block copolymer elastomer produced by Arkema; Pebax 5533: poly ether-amide block copolymer elastomer produced by Arkema; UD64D10: Polyurethane (TPU) produced by Bayer (Ure-Tech Group of Taiwan); Anox 20: an antioxidant produced by Chemtura Corporation USA.

Testing Methods

Ross Flex Test

1 . A 2mnn thick, 1 inch wide x 6 inch long test specimen was punched on a punching machine to make a 2.5mm wide flat cut perpendicular to the direction of the specimen's 6 inch length;

2. The cut specimen was put into the test tank of the GoTach Vertical Type Freezing Tester (GT-7006-V30), the cut on the inflection point and the two ends of the specimen clamped tightly;

3. Set testing temperature, began the bending test half hour later.

The bending test conditions are listed as below:

Condition 1 : Testing Temperature: -6°C; Number of Bending:150,000, Bending Angle:60°.

Condition 2: Testing Temperature: -20°C; Number of Bending:40,000, Bending Angle:90°.

Arkon Wear Resistance

The wear resistance test was carried out on the Arkon Abrasion Tester (ARKON), referencing to the testing method- section 2 description on JISK 6264-2:2005 wear testing method for vulcanized rubber and thermoplastic rubber.

A 1 .2cm wide, 2mm thick specimen was fixed encircledly on a 62+/- 0.5mm diameter rubber wheel. The grinding wheel was added 3724 g fixed load and formed a 15° angle with the specimen. The two mill oppositely 3000 times by rolling, and the volume ratio before and after milling was measured for comparison.

Tear Strength Testing

The tear strength of the specimen was measured according to the test method described in ASTM D624.

Dynamic Mechanics Test

The dynamic mechanics test was carried out according to the method described in ASTM D5418-07. The obtained comparison of dynamic mechanics curves and tan delta are listed in Figure 1 -2.

Specimen Preparation

Tables 1 -3 list the specimen components used in Examples 1 -9 and Comparative Examples 1 -1 1 . The specimen preparation procedure is shown as following: all components according to the content listed in Tables 1 -3 were added to the twin-screw extruder, and extruded at temperature about 240°C to form the composition using twin-screw extruder. The material strips were then granulated with a granulator. After drying at 80°C for 12 hours, the articles were plasticized at 250°C with an injection molding machine to shape the specimen. The prepared specimen was then to be tested for their properties and dynamic mechanics. The results are listed in Tables 1 -3 and Figures 1 -2.

Table 1

Examples 1 -3 listed in Table 1 is the polyamide alloy which was obtained by mixing nylon and vinyl copolymer blend in different combinations of maleic anhydride grafted ethylene-octylene elastomer (Fusabond® 493D), maleic anhydride grafted ternary ethylene propylene rubber EPDM (Fusabond® 416D), and styrene/butadiene rubber (PSBR), wherein the nylon as continuous phase and the vinyl copolymer blend as dispersed phase. These polyamide alloys (Examples 1 -3) have comparable wear resistance to poly ether-amide block copolymer elastomer (Pebax 7033, comparative example 1 ), and better tear resistance than poly ether-amide block copolymer elastomer. Besides, in terms of low temperature properties, the polyamide alloys whose vinyl copolymer blends were compounded from maleic anhydride grafted ethylene-octylene elastomer and ternary maleic anhydride grafted ethylene propylene rubber or maleic anhydride grafted ternary ethylene propylene rubber and styrene-butadiene rubber, have comparable low temperature flexibility (Examples 1 and 3). The polyamide alloy whose vinyl copolymer blend was compounded from maleic anhydride grafted ethylene-octylene elastomer and styrene-butadiene rubber, has better low temperature flexibility (Example 2).

Table 2

As shown in Table 2, compared to the polyamide alloys obtained by mixing nylon and compounded vinyl copolymer blend (Examples 4-6), the polyamide alloys

(Comparative Examples 2-4) obtained by mixing nylon and single type maleic anhydride modified vinyl copolymer has comparable tear resistance, but very poor low temperature flexibility and wear resistance. Besides, the non graft modified styrene-butadiene rubber was hard to blend with nylon, whereas in the polyamide alloys, the mixability problem has been solved because of the compound of maleic anhydride grafted ethylene-octylene elastomer or maleic anhydride grafted ternary ethylene propylene rubber.

Table 3

In Examples 7-9, the polyamide alloys obtained from Nylon 6, Nylon 1010 and compounded vinyl copolymer blend, compared to the poly ether-amide block copolymer elastomer (Comparative Examples 10-1 1 ), have improved tear resistance and

comparable low temperature (-6°C) flexibility and wear resistance. When mixing nylon with single type maleic anhydride grafted ethylene-octylene elastomer (Comparative Examples 6-8), the obtained alloy has fair tear resistance and low temperature flexibility, but very poor wear resistance.

Furthermore, dynamic mechanics tests using specimens in Examples 1 , 3, 4, 7 and

9 and Comparative Examples 1 and 9 were carried out using polyurethane in

Comparative Example 9. As shown in Figures 1 and 2, within the temperature range of -20°C to 40°C, the polyamide alloy specimens (Example 1 , 3, 4, 7, and 9) described herein possess very low tan delta meaning excellent energy recovery properties, whereas poly ether-amide block copolymer elastomer (comparative example 1 ), although having wider applicable temperature range, has poor energy recovery property, especially poorer than the polyamide alloys (example 1 , 3, 4, 7 and 9) in the temperature range of -20°C to 40°C. The energy recovery property of the polyurethane in the comparative example 9 was even poorer.

Claims

1 . A polyamide alloy comprising (a) 50-80wt% of at least one aliphatic polyamide and (b) 20-50wt% of vinyl copolymer blend wherein

the vinyl copolymer blend comprises at least two of (i) graft-modified

ethylene-olefin copolymer, (ii) graft-modified ethylene propylene rubber, and (iii) styrene rubber;

the graft-modified ethylene-olefin copolymer comprises 60-92wt% of the monomer units from ethylene and 8-40wt% of one or more monomer units from C_4-io olefins, based on the weight of the pre-g raft-modified ethylene-olefin copolymer; and

the graft-modified ethylene propylene rubber comprises 45-80wt% of the monomer units from the ethylene, 20-55wt% of the monomer units from the propylene, and 0-20wt% of one or more monomer units from C_5-io non-conjugated diene, based on the weight of the pre-g raft-modified ethylene propylene rubber.

2. The polyamide alloy of claim 1 comprising:

55-75wt%, preferably 60-70wt%, of the aliphatic polyamide, and

25-45wt%, preferably 30-40wt%, of the vinyl copolymer blend.

3. The polyamide alloy of claim 1 or 2 wherein the aliphatic polyamide is selected from: (i) the condensation product of one or more amino acids, (ii) the condensation product of one or more lactams, (iii) the condensation product of one or more amino acids with one or more lactams, the condensation product of one or more diamines with one or more diacids, or their salts, (iv) the condensation product of one or more lactams, one or more lactams, and one or more diacids, (v) the condensation product of one or more amino acids, one or more diamines, and one or more diacids, or their salts, or (vi) combinations of two or more thereof

4. The polyamide alloy of claim 1 , 2 or 3 wherein

the amino acid is a, ω-amino acids or 4-(aminomethyl)benzoic acid;

the a, ω-amino acids is selected from amino hexanoic acid, 7-amino heptanoic acid, 1 1 -amino-undocanic acid, 12-amino-dodecanoic acid, or combiations of two more thereof;

the lactam is selected from β, β-dimethyl propyl lactam, a, a-dimethyl propyl lactam, δ-volerolactam, ε-caprolactam, heptyl lactam, octyl lactam, dodecyl lactam, or combiations of two more thereof;

the diamine is selected from 1 ,6-hexane-diamine, 1 ,5-pentane-diamine, 1 ,12-dodecane-diamine, 1 ,4-butane-diamine, 1 ,8-octane-diamine, 1 ,10-decane-diamine, 1 -methyl-1 ,4-butane-diamine, 2-methyl-1 ,5-pentane-diamine,

2,2,4-thmethyl-1 ,6-hexane-diamine, isophorone diamine,

4,4'-diaminodicyclohexyl-methane, bis (3- methyl -4-amino cyclohexyl) methane, bis(p-aminocyclohexyl) methane, trimethyl-1 ,6-hexane-diamine,

5,6-dimethyl-pentane-1 ,6-diamine, or combiations of two more thereof; and

the diacid is selected from hexanedioic acid, butanedioic acid, cyclohexanedioic acid, octanedioic acid, nonanedioic acid, decanedioic acid, dodecandioic acid, or combiations of two more thereof.

5. The polyamide alloy of claim 1 , 2, 3, or 4 wherein the aliphatic polyamide is

the condensation product of caprolactam and dodecane-12-lactam;

the condensation product of caprolactam, hexanedioic acid and

1 ,6-hexane-diamine;

the condensation product of caprolactam, dodecane-12-lactam, hexanedioic acid and 1 ,6-hexane-diamine;

the condensation product of caprolactam, dodecane-12-lactam,

1 1 -amino-undocanic acid, nonanedioic acid, and 1 ,6-hexane-diamine;

the condensation product of caprolactam, dodecane-12-lactam,

1 1 -amino-undocanic acid, hexanedioic acid, and 1 ,6-hexane-diamine; or

the condensation product of dodecane-12-lactam, nonanedioic acid, and

1 ,6-hexane-diamine.

6. The polyamide alloy of any of claims 1 to 5 wherein the aliphatic polyamide has inherent viscosity larger than 0.9, and 5x10^"3g/cm³ m-cresol sample was measured at 25°C according to ISO 1628-1 .

7. The polyamide alloy of any of claims 1 to 6 wherein the graft-modified

ethylene-olefin copolymer and graft-modified ethylene comprises

65-88wt%, preferably 72-80wt%, of the monomer units from ethylene; and

12-35wt%, preferably 18-20wt%, of the one or more monomer units from C_4-io olefins.

8. The polyamide alloy of any of claims 1 to 7 wherein the graft-modified ethylene propylene rubber comprises 45-78wt%, preferably 45-75wt%, of the monomer units from ethylene; 20-53wt%, preferably 20-50wt%, of the monomer units from propylene; and 2-18wt%, preferably 5-15wt%, of the monomer units from C_5-i₀ non-conjugated diene.

9. The polyamide alloy of any of claims 1 to 8 wherein

the C-4-10 olefins is selected from C_4-i₀ a-olefins, 2-hexene, 2-heptene, 2-butene and 2-octene; the C_4-io a-olefin is selected from 1 -butene, 1 -pentene, 1 -hexene, 1 -heptene, or 1 -octene; and

the C-5-10 non-conjugated diene is selected from 1 ,4-pentadiene, 1 ,4-hexadiene,

1 ,5-hexadiene, 1 ,4-heptadiene, 1 ,5-heptadiene, 1 ,4-octadiene, or 1 ,5-octadiene.

10. The polyamide alloy of any of claims 1 to 9 wherein

the graft-modified ethylene-olefin copolymer and the graft-modified ethylene propylene rubber have grafted therewith one or more functional groups on their branches respectively including glycidyl methacrylate, methacrylic acid, methacrylic anhydride, maleic acid, maleic anhydride, fumaric acid, itaconic acid, citric acid, allyl succinic acid, cyclohex-4-ene-1 ,2-dicarboxylic acid, 4-methyl-cyclohex-4-ene-1 ,2-dicarboxylic acid, bicycle[2.2.1 ]hept-5-ene-2,3-dicarboxylic acid, 5-norbornene-2,3-dicarboxylic acid, itaconic anhydride, citric anhydride, allyl succinic anhydride,

cyclohex-4-ene-1 ,2-dicarboxylic anhydride, 4-methyl-cyclohex-4-ene-1 ,2-dicarboxylic anhydride, bicycle[2.2.1 ]hept-5-ene-2,3-dicarboxylic anhydride, or 5-norbornene

-2,3-dicarboxylic anhydride; and

the grafting degree is 0.01 -5wt% or 0.1 -3wt%.

1 1 . The polyamide alloy of any of claims 1 to 10 wherein

the styrene rubber is styrene/butadiene random copolymer or modified

styrene/butadiene random copolymer with 50-90mol% content; and

the modified styrene/butadiene random copolymer is maleic anhydride modified styrene/butadiene random copolymer.

12. The polyamide alloy of claim 1 1 wherei n

the vinyl copolymer blend comprises graft-modified ethylene-olefin copolymer and either the graft-modified ethylene propylene rubber or the styrene rubber;

the graft-modified ethylene-olefin copolymer is maleic anhydride modified ethylene-octylene copolymer;

the graft-modified ethylene propylene rubber is maleic anhydride modified ethylene-propylene-non-conjugated diene coplomer; and

and the styrene rubber is styrene/butadiene random copolymer or maleic anhydride modified styrene/butadiene random copolymer.

13. The polyamide alloy of claim 12 wherei n the modified styrene/butadiene random copolymer is maleic anhydride modified styrene/butadiene random copolymer.

14. The polyamide alloy of claim 1 1 wherei n the vinyl copolymer blend comprises graft-modified ethylene propylene rubber and the styrene rubber; the graft-modified ethylene propylene rubber is maleic anhydride modified ethylene propylene non conjugated copolymer; and the styrene rubber is selected from styrene/butadiene random copolymer or maleic anhydride modified styrene/butadiene random copolymer.

15. A method comprising blending at least one aliphatic polyamide and a vinyl copolymer blend to produce a mixture and extruding the mixture under conditions effective to produce a polyamide alloy as characterized in any one of claims 1 -14 wherein the vinyl copolymer blend comprises at least two of the following components: (i) graft-modified ethylene-olefin copolymer, (ii) graft-modified ethylene propylene rubber, and (iii) styrene rubber;

the aliphatic polyamide is present in 50-80wt%; the vinyl copolymer blend is present in 20-50wt%, based on the total weight of the resulting polyamide alloy;

the graft-modified ethylene-olefin copolymer comprises 60-92wt% of the monomer units from ethylene and 8-40wt% of one or more monomer units from C₄ olefins, based on the weight of the pre-g raft-modified ethylene-olefin copolymer;

the graft-modified ethylene propylene rubber comprises 45-80wt% of the monomer units from the ethylene, 20-55wt% of the monomer units from the propylene, and 0-20wt% of one or more monomer units from C₅ non-conjugated diene, based on the weight of the pre-g raft-modified ethylene propylene rubber.