Block copolymer composition for overmolding any nylon

• US 7,842,747 B2
• Filed: 10/13/2008
• Issued: 11/30/2010
• Est. Priority Date: 03/05/2004
• Status: Active Grant

• Current Assignee: Avient Corp.
• Original Assignee: GLS Corp. (Avient Corp.)
• Inventors: Gu, Jiren, Venkataswamy, Krishna
• Primary Examiner(s): Lipman; Bernard
• Application Number:
  US12/287,554
• Publication Number:
  US 20090069487A1
• Time in Patent Office: 778 Days
• Field of Search: 524/505
• US Class Current: 524/505
• CPC Class Codes: C08F 8/00 Chemical modification by after-treatment graft polymers, block polymers, crosslinking with unsaturated monomers or with polymers C08F251/00 - C08F299/00; of conjugated diene rubbers C08C
• CPC Class Codes: C08K 3/00 Use of inorganic substances as compounding ingredients
• CPC Class Codes: C08K 3/013 Fillers, pigments or reinforcing additives
• CPC Class Codes: C08K 3/34 Silicon-containing compounds
• CPC Class Codes: C08L 23/04 Homopolymers or copolymers of ethene
• CPC Class Codes: C08L 51/00 Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds for ABS polymers C08L55/02; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 53/02 of vinyl-aromatic monomers and conjugated dienes
• CPC Class Codes: C08L 53/025 modified
• CPC Class Codes: C09D 123/04 Homopolymers or copolymers of ethene
• CPC Class Codes: C09D 151/00 Coating compositions based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds based on ABS polymers C09D155/02; Coating compositions based on derivatives of such polymers
• CPC Class Codes: C09D 153/02 Vinyl aromatic monomers and conjugated dienes

Abstract

A thermoplastic elastomer (TPE) for overmolding (OM) a nylon substrate with an overmolded layer consists essentially of an inert filler, a plasticizer, preferably a mineral oil, and chosen combinations of ingredients from the following: (i) a functionalized “high rubber” SHDS (styrene-hydrogenated diene-styrene) having a functionality of 1%, the “small end blocks” together present in an amount in the range from about 8-25% by weight; (ii) hydrogenated SDS or SHDS block copolymer having polystyrene endblocks and a polymerized vinyl aromatic monomer in the poly(conjugated diene) midblock, the polystyrene endblocks together present in an amount in the range from 20-30% by weight of the block copolymer, excluding weight of the polystyrene in the polydiene midblock; (iii) a functionalized “high rubber” SHDS having a functionality of >1% but <2%, the “small end blocks” together present in an amount in the range from about 8-25% by weight; (iv) from 0-30% by weight of the composition, of a functionalized polyolefin (F3), the olefin having from 2 to 4 carbon atoms; (v) from 0-15% by wt of the composition, of a hydrogenated nonfunctionalized hydrogenated polystyrene-poly(conjugated diene)-polystyrene (SHDS) block copolymer; and, (vi) an additive to enhance the useful life of the composition.

Claims

1. A thermoplastic elastomer (“

TPE”

) composition for overmolding a predominantly nylon substrate consisting essentially of,

an essentially polyamide-free blend of,

(a) an inert filler present in an amount in the range from 5 to 40% by weight of the composition,

(b) a plasticizer, unreactive with an ingredient in the composition, present in a minor amount by weight relative to the composition;

(c) a block copolymer selected from the group consisting of

(C1), a polystyrene-polydiene-polystyrene block copolymer (SDS rubber), or an at least partially hydrogenated polystyrene-polydiene-polystyrene block copolymer (SHDS rubber), the SDS and SHDS each having polystyrene endblocks, one at each end of a polydiene midblock, which midblock includes a polymerized vinyl aromatic monomer, the polystyrene endblocks being together present in an amount in the range from about 20% to 30% by weight of the block copolymer, not including the polystyrene in the polydiene midblock, so that (C1) has a weight average molecular weight (“

Mw”

) high enough to be thermally stable at 282°

C. (540°

F.),

(C2), a functionalized at least partially hydrogenated “

high rubber”

SHDS having a functionality of essentially 1%, the “

small end blocks”

together present in an amount in the range from about 8-25% by weight (that is, each endblock has a much lower molecular weight than the rubbery midblock), and

(C3), a functionalized at least partially hydrogenated SHDS having a functionality of >

1% but <

2%, in which the end blocks are together present in an amount in the range from >

25%-35% by weight;

in any combination, provided that only (C2) may be present without (C1) and (C3);

(d) from 0-30% by weight of the composition, of a functionalized polyolefin (FP), the olefin having from 2 to 8 carbon atoms;

(e) from 0-15% by wt of the composition, of a hydrogenated nonfunctionalized hydrogenated polystyrene-polydiene-polystyrene (SHDS) block copolymer; and

,

(f) an additive to enhance the useful life of the composition.

2. The composition of claim 1 wherein,

in (C1), the polymerized vinyl aromatic monomer in the polydiene midblock is polystyrene;

the polydiene midblock is selected from hydrogenated polybutadiene, polyisoprene, and poly(isoprene/butadiene); and

,

(C1) has a molecular weight Mw in the range from 20,000-400,000.

3. The composition of claim 2, wherein

(C2) is present in an amount in the range from 5-25% by weight of the composition, and has a molecular weight in the range from 20,000-300,000;

(C3) is present in an amount in the range from 5-25% by weight of the composition and has a molecular weight in the range from 20,000-300,000; and

, plasticizer (b) is present in an amount from 10-40% by weight of the composition.

4. The composition of claim 3, including

from 1-20% of a substantially fully hydrogenated, non-functionalized SDS (“

SHDS”

).

5. The composition of claim 3, wherein (C1) and (C3) are absent, and (C2) is present in an amount from 10-40% by weight of the composition.

6. The composition of claim 1 wherein each functionalized SHDS is functionalized with a polar group selected from the group consisting of acid anhydride, carboxyl, carboxylic acid, and amine epoxy.

7. The composition of claim 1 wherein, if the functionalized polyolefin is present, the olefin is selected from ethylene and propylene, and the polyolefin is functionalized with maleic anhydride present in an amount from 0.5-4% of the grafted polymer.

8. A process for the preparation of an article comprising bonding a thermoplastic elastomeric overmolding composition to a nylon substrate, the process comprising, heating a composition according to claim 1 to a temperature in the range from about 182°

C.-282°

C. (360°

F.-540°

F.), followed by combining the heated composition with the polar substrate so as to overlie at least a portion of the substrate.

9. An article of arbitrary shape having a layer of the composition of claim 1 molded to at least a portion of the article'"'"'s surface.