Adhesive system

Abstract

The invention relates to an adhesive system comprising a protein and one or more polymers containing acetoacetoxy groups. It also relates to a method of producing a laminated wood based product and a particle board.

Description

EXAMPLES

Example 1

Veneered products were made by applying different compositions onto a 15×15 cm different particle boards followed by drying for 5 days. The dried adhesive layers were then remoistened followed by veneering a layer of 0.6 mm beech onto the boards. The assemblies were pressed during 1 minute at 130° C. The fiber tear (chisel) was tested.

The compositions tested were:

• 1) 14 g soy protein isolate (SPI) (Supro®500E from Solae), 100 ml water.
• 2) 8 g soy protein isolate (SPI) (Supro®500E from Solae), 50 g acetoacetylated polyvinyl alcohol solution (AAPVA) (Gohsefimer® Z-220 from Nippon Gohsei) (5 wt %),
• 3) 8 g soy protein isolate (SPI) (Supro®500E from Solae), 50 g acetoacetylated polyvinyl alcohol solution (AAPVA) (Gohsefimer® Z-220 from Nippon Gohsei) (10 wt %).

TABLE 1
First applied	Amount		Fiber tear (%)
component	first applied	Remoistening	Warm	Cold
SPI	2.7 g	1 g water	20–30	~5
SPI	2.7 g	1 g AAPVA	50–60	50–60
		(12 wt %)
SPI + AAPVA	3.7 g	1.4 g water	~90	~30
(5 wt %)
SPI + AAPVA	3.7 g	1.4 g water	100	100
(10 wt %)
SPI + AAPVA	3.7 g	1.1 g	100	100
(10 wt %)		polyvinylamine
		(11 wt %)

Example 2

A particle board was manufactured by mixing 864 g wood chips, having a moisture content of 2 weight %, with 205 g of an aqueous solution of about 11 weight % acetoacetylated polyvinyl alcohol (AAPVA) (Gohsefimer® Z-220 from Nippon Gohsei), followed by mixing in about 85 g of a soy protein isolate (SPI) (Prisolate® 601 EM from Food Partner). The SPI had a protein content of >90 weight % and a dry content of 94 weight %. The chips mixture was formed into a sheet of 30×30 cm and pressed at 185° C. for three minutes and pressed into a board of 16 mm thickness. The sequence of pressure was 160 kg/cm² during 30 s, 40 kg/cm² during 2.5 min and no pressure during the last 30 s. The tensile strength (internal bond, IB), thickness swelling (TSW) and water absorption (ABS) were measured.

A further particle board was manufactured in the same way as previously by mixing 994 g wood chips, having a moisture content of 2 weight %, with about 85 g of a soy protein isolate (Supro® 500E from Solae). The SPI had a protein content of >90 weight % and a dry content of 94 weight %. The tensile strength (internal bond, IB) was measured.

TABLE 2
				Moisture
				content
Wood				before		TSW	ABS
chips		Protein	AAPVA	pressing	IB	24 h	24 h
(g)	Protein	(g)	(11%), (g)	(%)	(kPa)	(%)	(%)
864	SPI	85.3	205	14.6	490	30.2	93.7
994	SPI	79.6	—	7.8	10	—*	—*
*not measured

Example 3

Particle boards were manufactured in a smaller scale by mixing 50.7 g wood chips respectively, having a moisture content of 2 weight %, with 1 g of acetoacetylated polyvinyl alcohol (AAPVA) (Gohsefimer® Z-220 from Nippon Gohsei), present as an aqueous solution of about 16.5 weight %, followed by mixing in soy protein isolate (SPI) (Supro® 500E from Solae) in various amounts. The SPI had a protein content of >90 weight % and a dry content of 94 weight %. A reference with no SPI and a reference with no AAPVA was also prepared. The chips mixtures were pressed into boards of 10 mm thickness. The pressing was made at 9 kg/cm² at 180-185° C. during 5 minutes. The internal bond strength (IB) was measured by gluing pieces of 5×5 cm onto two metal blocks and tearing them apart.

TABLE 3
Amount protein
(SPI)	Amount AAPVA	IB
(g)	(g)	(kPa)
—	1	127
0.2	1	222
0.5	1	359
2	1	480
5	1	322
5	—	176

Claims

1. Adhesive system comprising a protein and one or more polymers (P) containing acetoacetoxy groups.

2. Adhesive system according to claim 1, wherein the weight ratio protein to one or more polymers (P) is from about 1:2 to about 100:1.

3. Adhesive system according claim 1, wherein the weight ratio protein to one or more polymers (P) is from about 1:1 to about 20:1.

4. Adhesive system according to claim 1, which comprises an adhesive composition.

5. Adhesive system according to claim 4, wherein the adhesive composition comprises from about 5 to about 30 weight % of the protein.

6. Adhesive system according to claim 4, wherein the adhesive composition comprises from about 3 to about 15 weight % of the one or more polymers (P).

7. Adhesive system according to claim 1, comprising the protein and the one or more polymers (P) as separate components.

8. Adhesive system according to claim 1, wherein the one or more polymers (P) comprise acetoacetylated polyvinylalcohol.

9. Adhesive system according to claim 1, comprising one or more polymers (P1) containing amino groups or amide groups.

10. Adhesive system according to claim 1, wherein the one or more polymers (P1) comprise polyvinylamine.

11. Method of producing a wood based product comprising providing an adhesive system comprising a protein and one or more polymers (P) containing acetoacetoxy groups onto one or more pieces of a wood based material and joining the pieces with one or more further pieces of a material.

12. Method according to claim 11, wherein the adhesive system is provided onto pieces of a wood-based material as an adhesive composition.

13. Method according to claim 12, wherein the adhesive composition is dried after application and later activated by adding water or an aqueous composition comprising the one or more polymers (P) or an aqueous composition comprising one or more polymers (P1) containing amino groups or amide groups.

14. Method according to claim 11, wherein the adhesive system is provided onto pieces of a wood-based material as separate components, wherein one component comprises the protein and another component comprises the one or more polymers (P).

15. Method according to claim 14, wherein the first component applied comprises a protein solution or dispersion and the second component applied comprises a solution or dispersion of the one or more polymers (P).

16. Method according to claim 14, wherein the first component applied comprises a solution or dispersion of the one or more polymers (P) and the second component comprises the protein, either as a solution or dispersion or as a dry material.

17. Method according to claim 15, wherein the first component applied is dried after application before the second component is applied.

18. Method according to claim 11, wherein the adhesive system comprises one or more polymers (P1) containing amino groups or amide groups as a separate component.

19. Method according to claim 13, wherein the one or more polymers (P1) comprise polyvinylamine.

20. Method according to claim 18, wherein the one or more polymers (P1) comprise polyvinylamine.

21. Method according to claim 11, wherein the pieces are one or more of sheets, lamellas and veneers.

22. Method according to claim 21, wherein the wood based product is a laminated flooring material, veneered flooring, a veneered furniture material, plywood, a wall panel, a roofing panel or a laminated beam.

23. Method according to claim 11, wherein the pieces are wood chips or wood particles.

24. Method according to claim 23, wherein the wood based product is a chip-, particle- or fibre board, or an oriented strand board.

25. Wood based product obtained by the method according to claim 11.