Method of making a graft polymer

Abstract

Provided is a process for forming a polymer composition, wherein the process comprises (a) providing a slurry in an aqueous medium, wherein the slurry comprises (i) pellets comprising a polyolefin block copolymer, wherein the block copolymer comprises a crystalline block and an amorphous block, (ii) one or more vinyl monomers, (iii) one or more initiator, wherein the slurry comprises, by weight based on the total weight of the slurry, 0 to 0.01% of all surfactants, and 0 to 0.01% of all water-soluble polymers; and (b) polymerizing the one or more vinyl monomers.

Claims

1. A process for forming a polymer composition, wherein the process comprises (a) providing a slurry in an aqueous medium, wherein the slurry comprises (i) pellets comprising a polyolefin block copolymer, wherein the block copolymer comprises a crystalline block and an amorphous block, (ii) one or more vinyl monomers, (iii) one or more initiator, wherein the slurry comprises, by weight based on the total weight of the slurry, 0 to 0.01% of all surfactants, and 0 to 0.01% of all water-soluble polymers; and (b) polymerizing the one or more vinyl monomers.

2. The process of claim 1, wherein the vinyl monomer comprises one or more (meth)acrylate monomer, and wherein the slurry further comprises (iv) one or more non-aqueous solvent.

3. The process of claim 1, wherein the vinyl monomer comprises one or more vinyl aromatic monomer.

4. The process of claim 1, wherein the polymerizing is conducted by a method that comprises making a mixture at a temperature below 30° C. comprising the pellets, the vinyl monomer, and the initiator, in the absence of water, and then adding water to the mixture to create the slurry, and then heating the slurry to a temperature above 30° C.

5. The process of claim 1, wherein the one or more initiators comprises a thermal initiator, and the slurry is at a temperature high enough to cause the initiator to produce sufficient radicals to initiate polymerization of the vinyl monomer.

6. The process of claim 1, wherein the process is conducted at atmospheric pressure.

Description

EXAMPLE 2: GRAFTING WITH STYRENE MONOMER

(1) 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:

(2) TABLE-US-00002 TABLE 2 Grafting with Styrene % % test % Ex PO % PO styrene Toluene 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 .sup.(8A)soluble fraction 0.92% by weight based on the original weight of PO-B2 .sup.(8B)soluble fraction 0.99% by weight based on the original weight of PO-B2

(3) 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

(4) 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).

(5) 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.

(6) 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.

(7) 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:

(8) TABLE-US-00003 TABLE 3 Blends with acrylic polymer Acrylic- Example PO Type PO wt % 1 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

(9) 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

(10) Paintability Sample Preparation:

(11) 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.

(12) 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.

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

(14) 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.