US 6,048,909 AGranted

Foams having increased heat distortion temperature made from blends of alkenyl aromatic polymers and alpha-olefin/vinyl or vinylidene aromatic and/or sterically hindered aliphatic or cycloaliphatic vinyl or vinylidene interpolymers

AssigneeThe Dow Chemical Company

InventorsBharat I. Chaudhary, Russell P. Barry, Stephanie C. Cirihal

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Abstract

The present invention pertains to improved alkenyl aromatic polymer foams (and processes for their preparation) having increased heat distortion temperature and improved dimensional stability while maintaining good tensile/tear, creep and environmental dimensional change properties. The closed cell low density alkenyl aromatic polymer foams exhibit increased heat distortion temperature, when substantially random interpolymers of about 21 to about 65 mol % styrene are blended in. When these same alkenyl aromatic polymer foams are made without these interpolymers, the heat distortion temperature is not improved.

Claims29

Dependent claims

A process for making a closed cell alkenyl aromatic polymer foam having increased heat distortion temperature, which process comprises;

(I) forming a melt polymer material comprising;
(A) from about 80 to about 98 percent by weight (based on the combined weight of Components A and B) of one or more alkenyl aromatic polymers, and wherein at least one of said alkenyl aromatic polymers has a molecular weight (M.sub.w) of from about 100,000 to about 500,000;
and
(B) from about 2 to about 20 percent by weight (based on the combined weight of Components A and B) of one or more substantially random interpolymers having an I.sub.2 of about 0.1 to about 1000 g/10 min, an M.sub.w /M.sub.n of about 1.5 to about 20, comprising;
(1) from about 21 to about 65 mol % of polymer units derived from;
(a) at least one vinyl or vinylidene aromatic monomer, or
(b) at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, or
(c) 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 79 mol % of polymer units derived from at least one of ethylene and/or a C.sub.3-20 .alpha.-olefin;
and
(3) from 0 to about 20 mol % of polymer units derived from one or more of ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2);
and
(C) optionally, one or more nucleating agents and
(D) optionally, one or more other additives;
and
(II) further incorporating into said melt polymer material at an elevated pressure to form a Foamable gel
(E) one or more blowing agents present in a total amount of from about 0.2 to about 5.0 gram-moles per kilogram (based on the combined weight of Components A and B);
(III) cooling the foamable gel to an optimum temperature;
and
(IV) extruding the gel from step III through a die to a region of lower pressure to form a foam,
wherein as a result of said process the heat distortion temperature of said foam is increased by about 2.degree. C. or more relative to a corresponding foam without the substantially random interpolymer.

18 more elements

A process for making a closed cell alkenyl aromatic foam in the form of thermoplastic foam beads having increased heat distortion temperature, which process comprises;

(I) forming a melt polymer material comprising;
(A) from about 80 to about 98 percent by weight (based on the combined weight of Components A and B) of one or more alkenyl aromatic polymers, and wherein at least one of said alkenyl aromatic polymers has a molecular weight (M.sub.w) of from about 100,000 to about 500,000;
and
(B) from about 2 to about 20 percent by weight (based on the combined weight of Components A and B) of one or more substantially random interpolymers having an I.sub.2 of about 0.1 to about 1000 g/10 min, an M.sub.w /M.sub.n of about 1.5 to about 20, comprising;
(1) from about 21 to about 65 mol % of polymer units derived from;
(a) at least one vinyl or vinylidene aromatic monomer, or
(b) at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, or
(c) 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 79 mol % of polymer units derived from at least one of ethylene and/or a C.sub.3-20 .alpha.-olefin;
and
(3) from 0 to about 20 mol % of polymer units derived from one or more of ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2);
and
(C) optionally, one or more nucleating agents;
and
(D) optionally, one or more other additives;
and
(II) cooling and granulating the product from Step I to form discrete resin particles;
and
(III) suspending said resin particles in a liquid medium in which they are substantially insoluble;
(IV) incorporating into the suspension formed in Step III, at an elevated pressure and temperature in an autoclave or other pressure vessel;
(E) one or more blowing agents present in a total amount of from about 0.2 to about 5.0 gram-moles per kilogram (based on the combined weight of Components A and B);
(IV) rapidly discharging the product formed in Step IV into the atmosphere or a region of reduced pressure to form foam beads;
wherein
the heat distortion temperature of said foam is increased by about 2.degree. C. or more relative to a corresponding foam without the substantially random interpolymer.

21 more elements

A process for making expandable thermoplastic foam beads, which process comprises;

(I) providing;
(A) an alkenyl aromatic monomer and optionally a second monomer, which is different from and copolymerizable with said alkenyl aromatic monomer;
(II) dissolving in at least one of said monomers;
(B) one or more substantially random interpolymers comprising polymer units derived from;
(a) at least one vinyl or vinylidene aromatic monomer, or
(b) at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, or
(c) 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) polymer units derived from at least one of ethylene and/or a C.sub.3-20 .alpha.-olefin;
and optionally
(3) polymer units derived from one or more of ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2);
and
(C) optionally, one or more nucleating agents;
and
(D) optionally, one or more other additives;
and
(III) polymerizing the product from Step II to form thermoplastic particles;
and
(IV) incorporating during and/or after polymerization;
(E) one or more blowing agents into the thermoplastic particles;
and
(V) cooling the thermoplastic particles to form expandable foam beads.

18 more elements

A closed cell alkenyl aromatic polymer foam having increased heat distortion temperature, comprising;

(A) from about 80 to about 98 percent by weight (based on the combined weight of Components A and B) of one or more alkenyl aromatic polymers, and wherein at least one of said alkenyl aromatic polymers has a molecular weight (M.sub.w) of from about 100,000 to about 500,000;
and;
(B) from about 2 to about 20 percent by weight (based on the combined weight of Components A and B) of one or more substantially random interpolymers having an I.sub.2 of about 0.1 to about 1000 g/10 min, an M.sub.w /M.sub.n of about 1.5 to about 20;
comprising;
(1) from about 21 to about 65 mol % of polymer units derived from;
(a) at least one vinyl or vinylidene aromatic monomer, or
(b) at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, or
(c) 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 79 mol % of polymer units derived from at least one of ethylene and/or a C.sub.3-20 .alpha.-olefin;
and
(3) from 0 to about 20 mol % of polymer units derived from one or more of ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2);
and
(C) optionally, one or more nucleating agents and (D) optionally one or more other additives;
and
(E) one or more blowing agents present in a total amount of from about 0.2 to about 5.0 gram-moles per kilogram (based on the combined weight of Components A and B);
wherein
the heat distortion temperature of said foam is increased by about 2.degree. C. or more relative to a corresponding foam without the substantially random interpolymer.

14 more elements

Dependencies are inferred from the claim text.