Graft copolymer composition

Abstract

Provided is a polyolefin block copolymer having covalently attached residues of one or more vinyl monomer selected from the group consisting of one or more (meth)acrylic monomers, one or more vinyl aromatic monomers, and mixtures thereof.

Claims

1. A polyolefin block copolymer having covalently attached residues of one or more vinyl monomer selected from the group consisting of one or more (meth)acrylic monomers, one or more vinyl aromatic monomers, and mixtures thereof, wherein the polyolefin block copolymer comprises one or more amorphous block and one or more crystalline block, and wherein the percent grafting of the one or more vinyl monomer to the polyolefin block copolymer is 75% or higher.

2. The polyolefin block copolymer of claim 1, wherein the vinyl monomer consists of one or more (meth)acrylic monomer.

3. The polyolefin block copolymer of claim 1, wherein the vinyl monomer consists of one or more vinyl aromatic monomer.

Description

EXAMPLE 1: GRAFTING WITH (METH)ACRYLIC MONOMERS

(1) The following graft compositions using methacrylic monomers were made using method A as follows. The amounts shown are weight percent based on total polymer (polyolefin block copolymer plus all vinyl monomers). Example numbers beginning with “C” are comparative. “nm” means not measured.

(2) TABLE-US-00001 TABLE 1 Grafting with (meth)acrylic monomers Ex PO % PO % LMA % BMA % MMA % Toluene % grafting notes 1 PO-B1 70 9 0 21 0 nm (1) 2 PO-B1 70 9 0 21 30 100 (2) 3 PO-B1 70 0 30 0 30 100 (3) C4 PO-S1 100 0 0 0 30 nm (4) 5 PO-B1 70 0 0 30 30 100 (2) C6 PO-S1 100 0 0 0 0 nm (6) C7 PO-S2 70 21 0 9 0 100 (7) (1) Monomers did not swell the pellets, reaction was not performed. (2) Final pellets look good. (3) Final Pellets felt slightly sticky when warm. (4) Pellets swelled too much by the toluene. Pellets fused together when water was heated prior to monomer addition. Graft reaction not performed. (6) Pellets fused in water when heated. (7) Pellets appeared to swell when monomer was added, but the pellets agglomerated. Graft reaction was not performed.

(3) Comparative examples C4, C6, and C7 used a polyolefin polymer that was a statistical copolymer and not a block copolymer. All swelled so badly that a grafting reaction could not be conducted.

(4) Samples similar to those described in Table 1, using (meth)acrylic monomers for grafting, were made using method B. The resulting materials were equivalent to those described in Table 1.

EXAMPLE 2: GRAFTING WITH STYRENE MONOMER

(5) Grafting was conducted with styrene as the vinyl monomer, using method B. Toluene was used for swelling during the polymerization. The other solvents were used in the test for % grafting. The amounts shown are weight percent based on total polymer (polyolefin block copolymer plus all vinyl monomers). Results were as follows:

(6) TABLE-US-00002 TABLE 2 Grafting with Styrene Ex PO % PO % styrene % Toluene test solvent % grafting C8A PO-B2 100 0 0 THF.sup.(8A) nm C8B PO-B2 100 0 0 toluene.sup.(8B) nm  9 PO-B2 85 15 30 toluene 92.8 10 PO-B2 85 15 0 toluene 99.4 11 PO-B2 85 15 0 toluene 97.1 12 PO-B2 85 15 15 toluene 99.5 13 PO-B2 85 15 15 toluene 99.7 (8A)soluble fraction 0.92% by weight based on the original weight of PO-B2 (8B)soluble fraction 0.99% by weight based on the original weight of PO-B2

(7) Styrene monomer grafts well, with or without toluene. The highest level of toluene had high % grafting (92.8%), but that level was less high than samples grafted using less toluene or no toluene.

EXAMPLE 3: COMPATIBILITY WITH ACRYLIC POLYMER

(8) Two samples were prepared by blending polyolefin block copolymer with acrylic polymer particles (Acrylic-1). The Acrylic-1 had core of crosslinked poly(BA) and a shell of poly(MMA).

(9) To make comparative example C14, PO-B1 (80% by weight) plus Acrylic-1 (20% by weight) were processed with a two roll mill (Collin Mill (W. H. Collin GmbH Maschienefabrik, Aichach, Germany) at 185° C. for 5 minutes. After the milling was completed, the molten polymer was peeled from the metal rolls, and compression molded into 500 micrometer thick sheet with a CARVER™ press (Carver Press Inc., Menomonee Falls, Wis.) under the conditions of an operating temperature of 180° C. and pressing conditions of 5000 psi for 3 minutes, followed by 20000 psi for 2 minutes, and a 5-minute cooling period (at 23° C., room temperature) at 20000 psi.

(10) To make example Ex 15, the material Ex 5 (80% by weight) plus Acrylic-1 (20% by weight), was milled and pressed by the same method as comparative example C14.

(11) For each of C14 and Ex 15, a rectangle was cut from the pressed plaque and placed in a mechanical tensile tester and stretched in the longest direction. After removal from the tensile tester, the appearance of the sample was as follows:

(12) TABLE-US-00003 TABLE 3 Blends with acrylic polymer PO PO Acrylic-1 Example Type wt % wt % Observation C14 PO-B1 80 20 extreme stress whitening throughout the elongated portion of the sample 15 Ex 5 80 20 no stress whitening

(13) Table 3 shows that polyolefin block copolymer that is grafted with (meth)acrylic monomers (Ex 5) is much more compatible with other acrylic polymers than is un-grafted polyolefin block copolymer (PO-B1).

EXAMPLE 4—PAINTABILITY

Paintability Sample Preparation

(14) The dried grafted pellets of Ex 1 were placed into a metal mold and pressed into thin plaque with a thickness of 3.2 mm (⅛ inch). A CARVER press (Carver Press Inc., Menomonee Falls, Wis.) was used with an operating temperature of 185° C. and pressing conditions of 2.268 tons for 3 minutes, followed by 9.07 tons for 2 minutes, and a 5-minute cooling period (23° C.) at 9.07 tons. Dried pellets of PO-B1 were milled and pressed in the same way.

(15) Paintability was tested as follows: Water-based dyne pen (EnerDyne, made by Enercon Industries Corp., Menomonee Falls, Wis. USA) was used to test the surface energy of the plaque sample.

(16) TABLE-US-00004 TABLE 4 Paintability Test Sample ID Dyne Pen reading Grafted PO 32 Neat PO <30

(17) The higher reading on the Dyne Pen shows that the surface of the grafted sample will more readily receive paint or ink than does the surface of the ungrafted polyolefin block copolymer.