Adhesive system

Abstract

The invention relates to an adhesive system comprising a protein and one or more polymers containing primary, secondary, or tertiary amino groups, or pendant amide groups. It also relates to a method of producing a laminated wood based product and a particle board.

Description

EXAMPLES

Example 1

Particle boards were manufactured by mixing 864 g wood chips, having a moisture content of 2 weight %, with increasing amounts of an aqueous solution of about 4 weight % (11 weight % including salts) polyvinyl amine (Lupamin® 9095 from Basf), followed by mixing in about 80 g of a protein respectively. Both soy protein isolate (Supro® 500E from Solae) and soy meal (Provabis® 200/80 from Cargil Foods) was used. The SPI had a protein content of >90 weight % and a dry content of 94 weight % and the soy meal had a protein content of 52-56 weight % and a dry content of 93-95 weight %. The chips mixture was formed into sheets 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) was measured by gluing pieces of 5×5 cm onto two metal blocks and tear them apart. For the best IB-value also thickness swelling (TSW) and water absorption (ABS) was measured. Thickness swelling is measured by determining the degree of swelling after a piece of 5×5 cm has been immersed in water (20° C., 24 hrs). Water absorption is measured by determining the weight increase after a piece of 5×5 cm has been immersed in water (20° C., 24 hrs).

TABLE 1
				Moisture
				content
Wood			Polyvinyl	before		TSW	ABS
chips		Protein	amine	pressing	IB	24 h	24 h
(g)	Protein	(g)	(11%), (g)	(%)	(kPa)	(%)	(%)
994	SPI	79.6	—	7.8	10	—	—
994	SPI	79.6	42.3	7.0	130	—	—
994	SPI	79.6	106.7	9.0	390	65.7	120.9
994	soy	80	—	7.5	110	—	—
	meal
994	soymeal	80	43.2	7.2	260	—	—
	meal
994	soy	80	106.7	9.3	380	91.2	137.9
	meal

It is concluded that addition of polyvinylamine increases the internal bond strength.

Example 2

Particle boards were manufactured in a smaller scale by mixing 50.7 g wood chips respectively, having a moisture content of 2 weight %, with 10.9 g of an aqueous solution of about 4 weight % (11 weight % including salts) polyvinyl amine (Lupamin® 9095 from Basf), followed by mixing in about 5 g of a protein. As proteins a soy protein isolate (SPI) (Nurish® 1500 from Solae) having a protein content of >90 weight % and a dry content of about 94 weight %, a corn protein (Glutalys® from Roquette) having a protein content of about 57 weight % and a dry content of about 88 weight %, and a potato protein (Tubermine® from Roquette). The proteins were also tested without any amine- or amide-group-containing polymer, but with added water to achieve a moisture content before pressing for the chips mixture of 16.1 weight %. 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 2
Wood				Moisture
chips	Protein	Polyvinyl amine	Water	content	IB
(g)	(g)	(11%), (g)	(g)	(%)	(kPa)
50.7	SPI	—	9.5	16.1	97
50.7	SPI	10.9	—	16.1	387
50.7	corn	—	9.5	16.1	35
	protein
50.7	corn	10.9	—	16.1	293
	protein
50.7	potato	—	9.5	16.1	90
	protein
50.7	potato	10.9	—	16.1	247
	protein

It is concluded that the effect of addition of polyvinylamine is present for different types of proteins.

Example 3

Particle boards were manufactured by mixing 864 g wood chips, having a moisture content of 2 weight %, with 205 g of an aqueous solution of about 4 weight % (11 weight % including salts) polyvinyl amine (Lupamin® 9095 from Basf), followed by mixing in about 85 g of a protein. As proteins a soy protein isolate (Supro® 500E from Solae) having a protein content of >90 weight % and a dry content of 94 weight %, a corn protein (Glutalys® from Roquette) having a protein content of about 57 weight % and a dry content of about 88 weight % and a potato protein (Tubermine® from Roquette) having a protein content of 78 weight % and a dry content of 91 weight %, respectively were used. The moisture content of the chips mixture before pressing was determined. The chips mixtures were formed into sheets of 30×30 cm and pressed at 185° C. for three minutes into boards 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) was measured as well as thickness swelling and water absorption.

TABLE 3
				Moisture
				content
Wood			Polyvinyl	before		TSW	ABS
chips		Protein	amine	pressing	IB	24 h	24 h
(g)	Protein	(g)	(11%), (g)	(%)	(kPa)	(%)	(%)
864	soy	85.3	205	16.5	880	15.8	83.2
	protein
	isolate
864	Corn	85.3	205	16.6	470	22.3	94.0
	protein
864	potato	85.3	205	16.6	500	21.3	81.9
	protein

It is concluded the addition of polyvinylamine gives excellent internal bond strength and water resistance values for various protein types.

Example 4

Particle boards were manufactured in a smaller scale by mixing 50.7 g wood chips respectively, having a moisture content of 2 weight %, with 1.2 g of amine- or amide-group containing polymers added as solutions having dry contents of between 10 and 20 weight %, followed by mixing in 5.0 g of soy protein isolate (Supro® 500E from Solae). The SPI had a protein content of >90 weight % and a dry content of 94 weight %. 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 4
Wood			Dry content of
chips	Protein		polymer solution	IB
(g)	(g)	Polymer	(g)	(kPa)
50.7	—	Polyvinyl formamide1	1.2	477
50.7	5.0	Polyvinyl formamide1	1.2	530
50.7	—	Polyamine2	1.2	258
50.7	5.0	Polyamine2	1.2	645
50.7	—	Polyvinyl amine4	1.2	239
50.7	5.0	Polyvinyl amine4	1.2	927
50.7	—	Poly(vinyl alcohol-co-	1.2	262
		vinyl formamide)4
50.7	5.0	Poly(vinyl alcohol-co-	1.2	524
		vinyl formamide)4
50.7	—	Polyacryl amide5	1.2	154
50.7	5.0	Polyacryl amide5	1.2	671
50.7	—	Polyethylene imine6	1.2	536
50.7	5.0	Polyethylene imine6	1.2	1236
1Lupamin ® 9000 (Basf),
2Lupasol ® SC-86X (Basf),
3Lupamin ® 9095 (Basf),
4M6i (Erkol),
5Praestaret K325 (Basf),
6PEI 25000 (Aldrich)

Example 5

An adhesive composition was made by mixing 16 g of a soy protein isolate (Supro® 500E from Solae) and 100 g of an aqueous solution of about 7.5 weight % (22 weight % including salts) polyvinyl amine (Lupamin® 9095 from Basf). The SPI had a protein content of >90 weight % and a dry content of 94 weight %. The weight average molecular weight of the polyvinyl amine was 340.000 g/mol. As a reference 16 g of the same soy protein isolate (SPI) was mixed with 100 g of Milli-Q water. Veneered products were manufactured by gluing a 0.6 mm veneer of beech onto a particle board. The adhesive composition was applied onto a 15×15 cm particle in an amount of 120 g/m². The assembly was pressed during 2 minutes at 130° C. The gluing strength measured as fiber tear (chisel), the higher value the better) was measured 5, 30 and (only for SPI) 60 seconds and (only for SPI+polyvinylamine) as a cold assembly, respectively, after pressing.

	TABLE 5
	Fiber tear,	Fiber tear,	Fiber tear,	Fiber tear,
	5 s,	30 s,	60 s,	cold,
	(%)	(%)	(%)	(%)
SPI	30	30	20	—*
SPI + polyvinylamine	90	100	—*	70
*not measured

It is concluded that addition of polyvinyl amine increases the bond strength.

Example 6

An adhesive composition was made by mixing 36 g of a soy protein isolate (Supro® 500E from Solae) and 1.8 g of an aqueous solution of about 12.5 weight % a polyamineamide epichlorohydrin (PAAE) (Kymene® 557; from Hercules). The SPI had a protein content of >90 weight % and a dry content of 94 weight %. As a reference a composition of 12 g of the soy protein isolate in 100 ml water was used. The compositions were each applied onto 15×15 cm particle boards in an amount of 160 g/m². Veneers of beech (0.6 mm) were then pressed onto the boards. The assemblies were pressed during 1 minute at 130° C. The gluing strength measured as fiber tear (chisel) was measured on a warm assembly (directly after pressing) and on a cold assembly, respectively, after pressing.

	TABLE 6
	Fiber tear,	Fiber tear,
	warm	cold
	(%)	(%)
	SPI reference	90	50
	SPI + PAAE	50	20–30

It is concluded that the use of PAAE in combination with SPI has a negative impact on the the bond strength.

Example 7

An adhesive composition was made by mixing 8 g of a soy protein isolate (Supro® 500E from Solae) and 50 g of an aqueous solution of about 7.5 weight % (22 weight % including salts) polyvinyl amine (Lupamin® 9095 from Basf). The SPI had a protein content of >90 weight % and a dry content of 94 weight %. The weight average molecular weight of the polyvinyl amine was 340.000 g/mol. The adhesive composition was applied onto 15×15 cm particle boards in an amount of 120 g/m². The applied adhesive was allowed to dry for 5 days. The adhesive layers on two boards were then remoistened with 1.5 g water and 1.1 g of a solution (10 wt %) of acetoacetylated polyvinylalcohol (AAPVA) (Gohsefimer® Z-220 from Nippon Gohsei) respectively. Veneers of beech (0.6 mm) were then pressed onto the boards. The assemblies were pressed during 1 minute at 130° C. The gluing strength measured as fiber tear (chisel) was measured on a warm assembly (directly after pressing) and on a cold assembly, respectively, after pressing.

	TABLE 7
	Fiber tear,	Fiber tear,
	warm	cold
	(%)	(%)
	SPI + polyvinylamine	100	60–70
	SPI + polyvinylamine + AAPVA	100	100

It is concluded that addition of AAPVA further increases the bond strength.

Example 8

An adhesive composition was made by mixing 16 g of a soy protein isolate (Supro® 500E from solae) and 100 g of an aqueous solution of about 7.5 weight % (22 weight % including salts) polyvinyl amine (Lupamin® 9095 from BASF). The SPI had a protein content of >90 weight % and a dry content of 94 weight %. The weight average molecular weight of the polyvinyl amine was 340.000 g/mol. As a reference 16 g of the same soy protein isolate was mixed with 100 g of Milli-Q water. Flooring products for ANSI testing were manufactured by gluing a top layer of beech onto one side of a core material and a backing veneer onto the other. One assembly was pressed during 5 minutes at 90° C. and another assembly was pressed during 5 minutes at 130° C. As a further reference the same type of flooring product was manufactured using an EPI (emulsion polymer isocyanate) adhesive system. The delamination according to ANSI was tested (1 cycle: 31×73 mm pieces, water soaking for 4 h at 24° C., drying in oven for 19 h at 50° C.).

	TABLE 8
	Delamination (%)
	After 1 cycle	After 2 cycles	After 3 cycles
	Backing	Top	Backing		Backing	Top
Sample	layer	layer	layer	Top layer	layer	layer
EPI ref.	0	0	0.08	0	0.4	0
SPI ref. 90° C.	32	0	69	7	90	21
SPI +	0.6	0	18	0	25	0.09
polyvinylamine,
90° C.
SPI ref. 130° C.	2	0	77	0.5	91	0.8
SPI +	0	0	0.4	0	1	0
polyvinylamine,
130° C.

It is concluded that a performance equivalent to an EPI system can be achieved with the adhesive composition according to the present invention.

Claims

1. Adhesive system comprising a protein and one or more polymers (P) containing primary, secondary, or tertiary amino groups, or pendant amide groups.

2. Adhesive system according to claim 1, wherein the weight ratio protein to the one or more polymers (P) in the adhesive system is from about 2:1 to about 10:1.

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

4. Adhesive system according to claim 3, wherein the adhesive composition comprises from about 5 to about 50 weight % of protein.

5. Adhesive system according to claim 3, wherein the adhesive composition comprises from about 5 to about 15 weight % of the one or more polymers (P).

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

7. Adhesive system according to claim 6, wherein the one or more polymers (P) are present in an aqueous composition comprising from about 2 to about 25 weight % of polymers (P).

8. Adhesive system according to claim 1, wherein the one or more polymers (P) belong to the group of polyvinyl amine, poly(vinylalcohol-co-vinylamine), poly(vinylalcohol-co-vinylformamide), polyallyl amine, polyethylene imine and polyvinyl formamide.

9. Adhesive system according to claim 1, wherein the one or more polymers (P) comprise vinyl polymers.

10. Adhesive system according to claim 9, wherein the one or more polymers (P) belong to the group of polyvinyl amine, poly(vinylalcohol-co-vinylamine), poly(vinylalcohol-co-vinylformamide), polyallyl amine, and polyvinyl formamide.

11. Adhesive system according to claim 1, which comprises one or more polymers (P1) containing acetoacetoxy groups.

12. Adhesive system comprising a protein and one or more polymers (P) containing primary, secondary, or tertiary amino groups, or pendant amide groups being vinyl polymers.

13. Adhesive system according to claim 12, wherein the one or more polymers (P) belong to the group of polyvinyl amine, poly(vinylalcohol-co-vinylamine), poly(vinylalcohol-co-vinylformamide), polyallyl amine, and polyvinyl formamide, the weight ratio protein to the one or more polymers (P) in the adhesive system is from about 2:1 to about 10:1.

14. Method of producing a wood based product comprising providing an adhesive system comprising a protein and one or more polymers (P) containing primary, secondary, or tertiary amino groups, or pendant amide groups onto one or more pieces of a wood-based material and joining the pieces with one or more further pieces of a material.

15. Method according to claim 14 wherein the adhesive system is provided onto pieces of a wood-based material as an adhesive composition.

16. Method according to claim 15 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 acetoacetoxy groups.

17. Method according to claim 14 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).

18. Method according to claim 17 wherein a first applied component comprises a solution or dispersion of the one or more polymers (P) and a second applied component comprises the protein either as a solution or dispersion, or as a dry material.

19. Method according to claim 17 wherein a first applied component comprises a solution or dispersion of the protein and a second applied component comprises a solution or dispersion of the one or more polymers (P).

20. Method according to claim 18, wherein the first component applied is dried after application before the second component is applied.

21. Method according to claim 17 wherein a first applied component comprises a protein as a dry material, and the second component applied comprises a solution or dispersion of the one or more polymers (P).

22. Method according to claim 16, wherein the adhesive system comprises the one or more polymers (P1) as a separate component.

23. Method according to claim 14, wherein the pieces are sheets or lamellas.

24. Method according to claim 23, wherein the wood based product is a laminated flooring material.

25. Method according to claim 14, wherein the pieces are wood chips or wood particles.

26. Method according to claim 25, wherein the wood based product is a chip-, particle- or fibre board.

27. Method of producing a chip-, particle- or fibre board comprising providing an adhesive system comprising a protein and one or more polymers (P) containing primary, secondary, or tertiary amino groups, or pendant amide groups onto wood chips or wood particles and pressing together the wood chips or wood particles, the adhesive system is provided onto the wood chips or wood particles as separate components, wherein one component comprises the protein and another component comprises the one or more polymers (P)

28. Method according to claim 27, wherein the one or more polymers (P) in the form of a solution or dispersion are first added to the chips followed by addition of the protein in dry form.

29. Wood based product obtained by the method according to claim 14.