Bonding resin for wood-based composites providing light coloring, low platen sticking, and water resistance

Patent metadata

Field	Value
Publication number	US-2016024354-A1
Application number	US-201414338606-A
Country	US
Kind code	A1
Filing date	Jul 23, 2014
Priority date	Jul 23, 2014
Publication date	Jan 28, 2016
Grant date	—

Abstract

Disclosed herein are adhesives, wood-based composites incorporating the adhesives, and methods of forming wood-based composites using the adhesives. Wood-based composites formed using the adhesives demonstrate an optimal combination of characteristics desirable to the wood products industry. Specifically, the wood products formed using the adhesive demonstrate (1) a light appearance when wet; (2) relatively low moisture content after soaking in water; (3) relatively little thickness swelling after soaking in water; and (4) minimal adhesion to metal press platens during press-forming of the wood products.

First claim

1 . An adhesive emulsion, comprising:
(a) a continuous phase, comprising an aqueous, alkaline solution comprising a melamine/urea/formaldehyde resin; and (b) a dispersed phase, comprising a multifunctional aromatic isocyanate component; wherein the aqueous, alkaline solution comprising the melamine/urea/formaldehyde resin has a percent solids content of about 1.0% to about 90.0%; and wherein the melamine/urea/formaldehyde resin and the multifunctional aromatic isocyanate component are present in a ratio of about 92:8 to about 40:60 on a solids mass basis.

2 . The adhesive emulsion of claim 1 , wherein the aqueous, alkaline solution comprising the melamine/urea/formaldehyde resin has a percent solids content of about 40.0% to about 70.0%.

3 . The adhesive emulsion of claim 1 , wherein the aqueous, alkaline solution comprising the melamine/urea/formaldehyde resin is present in about 38.0-93.0 parts on a solids mass basis and the multifunctional aromatic isocyanate component is present in about 7.0-62.0 parts on a solids mass basis.

4 . The adhesive emulsion of claim 1 , wherein the multifunctional aromatic isocyanate component comprises PMDI (polymeric methylene diphenyldiisocyanate); toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, mixtures of toluene 2,4-diisocyanate and toluene 2,6-diisocyanate (TDI), 2,4′-methylene bis(phenylisocyanate), 4,4′-methylene bis(phenylisocyanate) (MDI), and combinations thereof.

5 . The adhesive emulsion of claim 1 , wherein the melamine/urea/formaldehyde resin comprises a melamine-based component that is about 5.0% or greater of the solids mass of the melamine/urea/formaldehyde resin.

6 . The adhesive emulsion of claim 1 , wherein the melamine/urea/formaldehyde resin comprises a urea-based component that is about 5.0% or greater of the solids mass of the melamine/urea/formaldehyde resin.

7 . The adhesive emulsion of claim 1 , wherein the melamine/urea/formaldehyde resin comprises a formaldehyde-based component that is about 30.0% or greater of the solids mass of the melamine/urea/formaldehyde resin.

8 . The adhesive emulsion of claim 1 , wherein the melamine/urea/formaldehyde resin is a condensation polymer derived from melamine, urea, and formaldehyde.

9 . The adhesive emulsion of claim 1 , wherein the aqueous, alkaline solution comprising a melamine/urea/formaldehyde resin has a pH of about 7.5-11.

10 . The adhesive emulsion of claim 1 , wherein the aqueous, alkaline solution comprising the melamine/urea/formaldehyde resin further comprises an alkaline component.

11 . The adhesive emulsion of claim 9 , wherein the alkaline component is selected from the group consisting of sodium hydroxide, potassium hydroxide, ammonium hydroxide, and organic amines.

12 . The adhesive emulsion of claim 1 , further comprising an additive selected from the group consisting of surfactants, diluents, viscosifying agents, colorants, preservatives, formaldehyde scavengers, and combinations thereof.

13 . The adhesive emulsion of claim 1 , wherein the adhesive emulsion contains no catalyst.

14 . A wood-based composite comprising wooden elements adhered together by a polyurethane polymer formed by the reaction of a continuous phase and a dispersed phase of an adhesive emulsion, comprising:
(a) a continuous phase, comprising an aqueous, alkaline solution comprising a melamine/urea/formaldehyde resin; and (b) a dispersed phase, comprising a multifunctional aromatic isocyanate component; wherein the aqueous, alkaline solution comprising the melamine/urea/formaldehyde resin has a percent solids content of about 1.0% to about 90.0%; and wherein the melamine/urea/formaldehyde resin and the multifunctional aromatic isocyanate component are present in a ratio of about 92:8 to about 40:60 on a solids mass basis.

15 . The wood-based composite of claim 14 , wherein the wooden elements are selected from the group consisting of strands, flakes, particles, fibers, veneer, and combinations thereof.

16 . The wood-based composite of claim 14 , wherein the wood-based composite is of a type selected from the group consisting of oriented strandboard, particleboard, medium-density fiberboard, oriented strand lumber, parallel strand lumber, laminated veneer lumber, laminated strand lumber, and plywood.

17 . The wood-based composite of claim 14 , further comprising an additive selected from the group consisting of a wax, a second adhesive, a preservative, a fire retardant, a coating, a sealant, a colorant, a marking, and combinations thereof.

18 . A method of forming a wood-based composite, comprising:
(a) coating a plurality of wooden elements with an adhesive emulsion to provide coated wooden elements, the adhesive emulsion comprising:
(i) a continuous phase, comprising an aqueous, alkaline solution comprising a melamine/urea/formaldehyde resin; and
(ii) a dispersed phase, comprising a multifunctional aromatic isocyanate component;
wherein the aqueous, alkaline solution comprising the melamine/urea/formaldehyde resin has a percent solids content of about 1.0% to about 90.0%; and
wherein the melamine/urea/formaldehyde resin and the multifunctional aromatic isocyanate component are present in a ratio of about 92:8 to about 40:60 on a solids mass basis;
(b) forming the coated wooden elements into a mat; (c) applying pressure to the mat with a press; and (d) heating the mat to form the wood-based composite.

19 . The method of claim 17 , wherein the adhesive emulsion is applied at level of about 1-15%, based on the dry mass of the wooden elements.

20 . An adhesive composition, comprising;
(a) a suspended phase comprising melamine/urea/formaldehyde resin powder; and (b) a continuous phase comprising a multifunctional aromatic isocyanate component; wherein the melamine/urea/formaldehyde resin powder and the multifunctional aromatic isocyanate component are present in a ratio of about 1:99 to 55:45 on a solids mass basis.

21 . An adhesive composition, comprising;
(a) a suspended phase comprising a melamine/formaldehyde resin powder; and (b) a continuous phase comprising a multifunctional aromatic isocyanate component; wherein the melamine/formaldehyde resin powder and the multifunctional aromatic isocyanate component are present in a ratio of about 1:99 to 55:45 on a solids mass basis.

Assignees

• Weyerhaeuser Nr Co

Inventors

• Winterowd Jack G
• Parker Erik M

Classifications

• B32B2317/16

  Wood, e.g. woodboard, fibreboard, woodchips · CPC title

• B32B21/02

  the layer being formed} of fibres, chips, or particles {, e.g. MDF, HDF, OSB, chipboard, particle board, hardboard · CPC title

• B32B2419/04

  Tiles for floors or walls · CPC title

• B32B21/042

  of wood (B32B21/13 takes precedence) · CPC title

• B32B2419/06

  Roofs, roof membranes · CPC title