Polydiorganosiloxane compositions and methods for use thereof in forming wood plastic composites

Patent metadata

Field	Value
Publication number	US-12215233-B2
Application number	US-202318482042-A
Country	US
Kind code	B2
Filing date	Oct 6, 2023
Priority date	Aug 7, 2019
Publication date	Feb 4, 2025
Grant date	Feb 4, 2025

Abstract

A polydiorganosiloxane is useful in a composition and a method for preparing a wood plastic composite article. The wood plastic composite article is useful as a building material. The polydiorganosiloxane may be added to the composition in liquid form or may form part of a solid carrier component used to make the wood plastic composite article.

First claim

The invention claimed is:

1. A composition for preparing a wood plastic composite article, said composition comprising:
40 weight % to 70 weight % of (a) a lignocellulosic-based filler;
29 weight % to 59 weight % of (b) an ethylene-based polymer;
1 weight % to 4 weight % of (c) a trialkyl-siloxy terminated polydialkylsiloxane of formula

where each R is an independently selected alkyl group of 1 to 18 carbon atoms, and subscript x has a value sufficient to give the polydiorganosiloxane a viscosity of 5,000 mPa·s to 50,000 mPa·s as measured at 25° C. at 0.1 RPM to 50 RPM on a Brookfield Dy-III cone & plate viscometer with #CP-52 spindle; and
0 to 4 weight % of (d) a maleated ethylene-based polymer;
each based on combined weights of starting materials (a), (b), (c), and (d) in said composition.

2. The composition of claim 1 , where starting material (a) the lignocellulosic-based filler comprises a lignocellulosic material derived from wood, plants, agricultural by-products, chaff, sisal, bagasse, wheat straw, kapok, ramie, henequen, corn fiber or coir, nut shells, flax, jute, hemp, kenaf, rice hulls, abaca, peanut hull, bamboo, straw, lignin, starch, or cellulose and cellulose-containing products, and combinations thereof, and starting material (a) is present in an amount of 45 weight % to 65 weight %.

3. The composition of claim 1 , where (a) the lignocellulosic-based filler is a wood filler comprising lignin in an amount of 18 weight % to 35 weight % and carbohydrate in an amount of 65 weight % to 75 weight %, and optionally inorganic minerals in an amount up to 10 weight %.

4. The composition of claim 1 , where (a) the lignocellulosic-based filler is a wood filler comprising 29 weight % to 57 weight % alpha-cellulose, based on dry weight of the wood filler.

5. The composition of claim 1 , where starting material (b) the ethylene-based polymer is selected from the group consisting of High Density Polyethylene (HDPE), Medium Density Polyethylene (MDPE), Low Density Polyethylene (LDPE), Linear Low Density Polyethylene (LLDPE), Low Density Low Molecular Weight Polyethylene (LDLMWPE), and a combination thereof, and starting material (b) is present in an amount of 31 weight % to 51 weight %.

6. The composition of claim 1 , where (b) the ethylene-based polymer is selected from the group consisting of HDPE, LLDPE, and a combination thereof.

7. The composition of claim 1 , where (b) the ethylene-based polymer comprises >50% recycled polyethylene.

8. The composition of claim 1 , where in starting material (c) the trialkyl-siloxy terminated polydialkylsiloxane, each R is an alkyl group of 1 to 12 carbon atoms, subscript x has a value sufficient to give the polydiorganosiloxane a viscosity of 5,000 mPa·s to 20,000 mPa·s, and starting material (c) is present in an amount of 1 weight % to 2 weight %.

9. The composition of claim 1 , where in starting material (c) the trialkyl-siloxy terminated polydialkylsiloxane each R is an alkyl group of 1 to 6 carbon atoms, and subscript x has a value sufficient to give the trialkyl-siloxy terminated polydialkylsiloxane a viscosity of 5,000 mPa·s to 15,000 mPa·s.

10. The composition of claim 1 , where starting material (c) is a trimethylsiloxy-terminated polydimethylsiloxane.

11. The composition of claim 1 , where the composition further comprises an additional starting material selected from the group consisting of (e) an additional filler which is distinct from the lignocellulosic-based filler of starting material (a), (f) a colorant, (g) a blowing agent, (h) a UV stabilizer, (i) an antioxidant, (j) a process aid, (k) a preservative, (l) a biocide, (m) a flame retardant, (n) an impact modifier, and (o) a combination of two or more of (e) to (n).

12. The composition of claim 11 , where starting material (e) the additional filler is present in an amount of 10 weight % to 15 weight %, and starting material (e) is a mineral filler.

13. A method for preparing a wood plastic composite article comprises:
(1) preparing composition for preparing a wood plastic composite article by combining starting materials comprising:
40 weight % to 70 weight % of (a) a lignocellulosic-based filler;
29 weight % to 59 weight % of (b) an ethylene-based polymer;
1 weight % to 4 weight % of (c) a trimethylsiloxy-terminated polydialkylsiloxane of formula

where each R is an independently selected alkyl group of 1 to 18 carbon atoms, and subscript x has a value sufficient to give the polydiorganosiloxane a viscosity of 5,000 mPa·s to 50,000 mPa·s as measured at 25° C. at 0.1 RPM to 50 RPM on a Brookfield Dy-III cone & plate viscometer with #CP-52 spindle; and
0 to 4 weight % of (d) a maleated ethylene-based polymer; each based on combined weights of starting materials (a), (b), (c), and (d) in said composition; and
(2) forming the wood plastic composite article from the composition.

14. The method of claim 13 , further comprising:
(i) mixing (a) the lignocellulosic based filler and (b) the ethylene-based polymer before adding (c) the trimethylsiloxy-terminated polydialkylsiloxane;
(ii) heating (b) the ethylene-based polymer to melt (b) the ethylene-based polymer before and/or during forming the composition;
(iii) mixing a mixture of (a) the lignocellulosic-based filler and (c) the polydiorganosiloxane before adding (b) the ethylene-based polymer; or
(iv) any combination of (ii) and (i) or (iii).

15. The method of claim 13 , further comprising:
(i) (c) the trimethylsiloxy-terminated polydialkylsiloxane is a liquid when combining (c) the polydiorganosiloxane with another starting material of the composition; or
(ii) (c) the polydiorganosiloxane is present within a solid carrier component, and the method further comprises melting the solid carrier component when combining (c) the polydiorganosiloxane with another starting material of the composition.

16. The method of claim 13 , where
(i) forming the wood plastic composite article from the composition further comprises forming the composition into a desired shape;
(ii) forming the wood plastic composite article from the composition comprises extruding the composition;
(iii) forming the wood plastic composite article from the composition comprises molding the composition; or
(iv) any combinations of (i) to (iii).

17. The method of claim 13 , further comprising using the wood plastic composite article as a building material selected from the group consisting of decking, railing, fencing, siding, trim, skirts, and window framing.

18. The method of claim 17 , where the building material is decking and the method further comprises: 3) adding a cap stock layer to the decking after step 2).

19. A solid carrier component comprising:
10 weight % to 30 weight % of (i) a trimethylsiloxy-terminated polydialkylsiloxane of formula

where each R is an independently selected alkyl of 1 to 18 carbon atoms, and subscript x has a value sufficient to give the polydiorganosiloxane a viscosity of 5,000 mPa·s to 50,000 mPa·s measured at 25° C. at 0.1 RPM to 50 RPM on a Brookfield Dy-III cone & plate viscometer with #CP-52 spindle; and
70 weight % to 90 weight % of (ii) a polymer component selected from the group consisting of:
an ethylene-based polymer,
a

Assignees

• Dow Silicones Corp

Inventors

• Mecca Jodi
• Keenihan James
• Courtemanche Marc-Andre
• Bruce Keith
• Chorvath Igor
• Gaal Sean

Classifications

• C08L2205/03

  containing three or more polymers in a blend · CPC title

• C08L23/0869

  with unsaturated acids, e.g. [meth]acrylic acid; with unsaturated esters, e.g. [meth]acrylic acid esters · CPC title

• C08L97/02 Primary

  Lignocellulosic material, e.g. wood, straw or bagasse {(manufacture of articles made from lignocellulosic material by dry processes B27N)} · CPC title

• C08L83/04

  Polysiloxanes · CPC title

• C08L23/06 Primary

  Polyethylene · CPC title