Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
1999-03-10
2001-02-20
Edwards, N (Department: 1771)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S373000, C442S199000, C442S361000
Reexamination Certificate
active
06190768
ABSTRACT:
FIELD OF THE INVENTION
This invention is related to fibers and to fabrics and articles fabricated therefrom. The fibers are prepared from polymers which comprise at least one substantially random interpolymer comprising polymer units derived from one or more &agr;-olefin monomers with one or more vinyl or vinylidene aromatic monomers and/or hindered aliphatic or cycloaliphatic vinyl or vinylidene monomers.
BACKGROUND OF THE INVENTION
A variety of fibers and fabrics have been made from thermoplastics, such as polypropylene, highly branched low density polyethylene (LDPE) made typically in a high pressure polymerization process, linear heterogeneously branched polyethylene (e.g., linear low density polyethylene made using Ziegler catalysis), blends of polypropylene and linear heterogeneously branched polyethylene, blends of linear heterogeneously branched polyethylene, and ethylene/vinyl alcohol copolymers.
Of the various polymers known to be extrudable into fiber, highly branched LDPE has not been successfully melt spun into fine denier fiber. Linear heterogeneously branched polyethylene has been made into monofilament, as described in U.S. Pat. No. 4,076,698 (Anderson et al.), the disclosure of which is incorporated herein by reference, and into fine denier fiber, as disclosed in U.S. Pat. No. 4,644,045 (Fowells), U.S. Pat. No. 4,830,907 (Sawyer et al.), U.S. Pat. No. 4,909,975 (Sawyer et al.) and in U.S. Pat. No. 4,578,414 (Sawyer et al.), the disclosures of which are incorporated herein by reference.
Blends of such heterogeneously branched polyethylene have also been successfully made into fine denier fiber and fabrics, as disclosed in U.S. Pat. No. 4,842,922 Krupp et al.), U.S. Pat. No. 4,990,204 (Krupp et al.) and U.S. Pat. No. 5,112,686 (Krupp et al.), the disclosures of which are all incorporated herein by reference.
In addition to heterogeneously branched LLDPE, fibers have also been made from narrow molecular weight distribution ethylene copolymers produced using the so called single site catalysts as described by Davey et al., in U.S. Pat. No. 5,322,728 and WO 94/12699.
Fibers have also been made from other polymeric materials. U.S. Pat. No. 4,425,393 (Benedyk) discloses monofilament fiber made from polymeric material having an elastic modulus from 2,000 to 10,000 psi. which includes plasticized polyvinyl chloride (PVC), low density polyethylene (LDPE), thermoplastic rubber, ethylene-ethyl acrylate, ethylene-butylene copolymer, polybutylene and copolymers thereof, ethylene-propylene copolymers, chlorinated polypropylene, chlorinated polybutylene or mixtures of those.
Many applications for such fibers require varying degrees of softness or stiffness and have different operating temperature requirements depending upon the application. For instance U.S. Pat. No. 5,068,141 (Kubo et al.) discloses making nonwoven fabrics from continuous heat bonded filaments of certain heterogeneously branched LLDPE having specified heats of fusion.
The present invention relates to fibers and fabricated articles therefrom prepared from polymer compositions which comprise at least one substantially random interpolymer comprising polymer units derived from one or more &agr;-olefin monomers with one or more vinyl or vinylidene aromatic monomers and/or a hindered aliphatic or cycloaliphatic vinyl or vinylidene monomers or blends therefrom. Unique to these novel materials is the ability to precisely tune both the glass transition process (location, amplitude and width of transition) in the vicinity of the ambient temperature range, and the stiffness and modulus of the material in its final state. Both these factors can be controlled by varying the relative amount of &agr;-olefin(s) and vinyl or vinylidene aromatic and/or hindered aliphatic vinyl or vinylidene monomers in the final interpolymer or blend therefrom. Further variation in the Tg of the polymer composition used in the present invention can be introduced by variation of the type of component blended with the substantially random interpolymer including the presence of one or more tackifiers in the final formulation. This control of the Tg and modulus allows the stiffness or softness of the fiber to be varied to suit a given application.
BRIEF SUMMARY OF THE INVENTION
We have discovered new fibers, fabrics and articles fabricated therefrom. These fibers and fabrics are made from novel substantially random interpolymers of &agr;-olefins and vinyl or vinylidene aromatic and/or hindered aliphatic or cycloaliphatic vinyl or vinylidene monomers or blends therefrom. These interpolymers have a processability in fiber and fabric processes similar to homogeneous and heterogeneously branched linear low density polyethylene, which means that the new fibers and fabrics can be produced on the conventional equipment used for the various synthetic fiber or fabric processes (e.g., continuous wound filament, spun bond, and melt blown). The present invention pertains to fibers comprising;
(A) from about 50 to 100 wt % (based on the combined weights of Components A and B) of at least one substantially random interpolymer having an I
2
of from about 0.1 to about 1,000 g/10 min, a density greater than about 0.9300 g/cm
3
, and an M
w
/M
n
of about 1.5 to about 20; which comprises;
(1) from about 0.5 to about 65 mol % of polymer units derived from;
(i) at least one vinyl or vinylidene aromatic monomer, or
(ii) at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, or
(iii) a combination of at least one aromatic vinyl or vinylidene monomer and at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, and
(2) from about 35 to about 99.5 mol % of polymer units derived from ethylene and/or at least one C
3-20
&agr;-olefin; and
(B) from 0 to about 50% by weight (based on the combined weights of Components A and B) of at least one tackifier.
The fibers and fabrics and fabricated articles of the present invention show good elasticity, abrasion resistance, good viscoelastic properties such as resiliency, and possess both styrenic and olefinic functionality providing compatability with other styrenic-based materials and enabling their use as processing aids. For the fibers having a Tg close to body temperature, fabrics and clothing or other articles comprising said fibers and for use on the human body show excellent body conformability.
Thus the fibers of the present invention have applications such as chemical separation membranes, dust masks, carpet fibers, elastic fibers, wigs, doll hair, personal/feminine hygiene applications, diapers, athletic sportswear, shin pads, wrinkle free and form-fitting apparel, upholstery, and medical applications including, but not restricted to, surgical masks, bandages, gamma sterilizable fibers.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
All references herein to elements or metals belonging to a certain Group refer to the Periodic Table of the Elements published and copyrighted by CRC Press, Inc., 1989. Also any reference to the Group or Groups shall be to the Group or Groups as reflected in this Periodic Table of the Elements using the IUPAC system for numbering groups.
Any numerical values recited herein include all values from the lower value to the upper value in increments of one unit provided that there is a separation of at least 2 units between any lower value and any higher value. As an example, if it is stated that the amount of a component or a value of a process variable such as, for example, temperature, pressure, time and the like is, for example, from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, it is intended that values such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 etc. are expressly enumerated in this specification. For values which are less than one, one unit is considered to be 0.0001, 0.001, 0.01 or 0.1 as appropriate. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this ap
Stewart Kenneth B
Turley Robert R.
Edwards N
The Dow Chemical Company
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