WO1998050467A1

WO1998050467A1 - Resin composition and board made by using the same

Info

Publication number: WO1998050467A1
Application number: PCT/JP1998/001426
Authority: WO
Inventors: Tsuyoshi Kono
Original assignee: Tsuyoshi Kono
Priority date: 1997-05-05
Filing date: 1998-03-30
Publication date: 1998-11-12
Also published as: JP3361819B2

Abstract

A resin composition excellent in strength performance and water resistance due to the use of a lignin; and a board excellent in strength performance and water resistance due to the use of the resin composition. The resin composition is one which is obtained by reacting a lignin with a phenol and an aldehyde, and in which at least 30 wt.% of the nonvolatile matter is accounted for by ingredients derived from a gramineous lignin. The resin composition is added to a lignocellulosic substance in an amount of 0.2 to 30 wt.% on a dry basis based on the lignocellulosic substance, and the mixture is heated and pressed to obtain a board.

Description

TECHNICAL FIELD Resin composition and board using the same

The present invention relates to a resin composition using lignin used as an adhesive, a binder, a molding material, and the like, and a board using the same as an adhesive, such as a particle board and a fiber board.

Landscape technology

Since phenol aldehyde resins exhibit excellent water resistance, they are widely used in adhesives for wood and the like, particularly in fields requiring water resistance.

On the other hand, research on the production of adhesives by reacting lignin separated and purified from waste wood pulp with phenols and formaldehyde has been conducted.

24, p84, Hanui et al. (19669) ”, Japanese Patent Publication No. 53-284642, Japanese Patent Publication No. 62-51693, Japanese Patent Publication No. Hei 6-50 Japanese Patent Publication No. 6 967, Japanese Patent Publication No. 7-5 3 858

However, the cost of these lignin-based adhesives is not significantly different from that of conventional phenol-aldehyde resin adhesives due to the need for complicated manufacturing processes and the use of multi-star phenol. However, the strength performance and water resistance have not reached the level of conventional phenol aldehyde resin adhesives and have not been put to practical use.

An object of the present invention is to provide a resin composition which exhibits excellent strength performance and water resistance by using lignin, has a high use ratio of lignin, and is economically advantageous as compared with a commercially available phenol aldehyde resin. It is in.

Another object of the present invention is to provide a board having excellent strength performance and water resistance using such a resin composition.

Disclosure of the invention

The present inventors have found that lignin of the Gramineae plant is extremely advantageous as a raw material for a resin composition. Lignin is industrially produced by extraction from pulp waste liquor, but until now pulp production in Japan and Western Europe has been essentially only wood pulp. As a result, research on the use of lignin was limited to wood lignin.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have obtained a resin composition having excellent strength performance and water resistance by effectively using lignin of the grass family. That is, the resin composition of the present invention is a resin composition in which phenols and aldehydes are reacted with lignin, and that 30% or more of non-volatile components are components derived from a lignin plant of the Poaceae family. It is a feature.

The board of the present invention may be formed by adding a resin composition containing the above resin composition or a component derived from lignin derived from a grass plant of 30% by weight or more to a lignocellulose substance, and heating and pressurizing the board. For example, a particle board, a fiber board, and the like are included.

Gramineous plant lignin to be used in the resin composition of the present invention includes lignin of all grasses such as rice, wheat, bamboo, sugar cane, ash and kolyan.

Such lignin of the Gramineae plant may be of course directly extracted from the Gramineae plant, but the one extracted from the pulp waste liquid is industrially advantageous. When lignin extracted from pulp waste liquid is used, the types of digestion methods include so-called chemical pulping, semi-chemical pulping, thermomechanical pulping, and organic methods such as the Kraft method, the sulfite method, and the soda method. There are solvent methods and the like, and any of them can be used. The lignin used in the resin composition of the present invention is preferably composed of only the above-mentioned lignin of the grass family, but if it is 50% by weight or less, lignin other than the grass family such as wood may be used. Good.

As the phenols used in the resin composition of the present invention, all phenols such as phenol, cresol, xylenol, bisphenol A, bisphenol F, resorcinol, etc. can be used. It is particularly preferable to use phenol from the viewpoint. The use amount thereof is preferably 100% by weight or less, and particularly preferably 5 to 60% by weight, based on the lignin of the grass family. The amount used may exceed 100% by weight, but it will only increase the cost and cannot improve the physical properties.

As the aldehydes, formaldehyde, acetate aldehyde, furfural, benzaldehyde, dalioxal, etc. can be used, but in terms of performance and cost. It is particularly preferred to use formaldehyde or furfural. These may be used alone or in combination of two or more. The amount used is preferably in the range of 0.2 to 5 in terms of the molar ratio of formyl group to phenol monomer.

When formaldehyde is used in combination with other aldehydes, the use ratio is preferably at least 30% by weight, more preferably at least 50% by weight of the whole aldehyde. When furfural is used in combination with other aldehydes, the use ratio is preferably at least 10% by weight, more preferably at least 30% by weight of the whole aldehyde.

As formaldehyde, all formaldehydes such as formalin, paraformaldehyde and polyxylene can be used. The amount used is preferably in the range of 1.2 to 5.0, more preferably in the range of 1.8 to 3.5, as a molar ratio to the phenol monomer. By using a small amount of formaldehyde, the resin composition exhibits excellent strength performance.

When furfural is used, the amount of the furfural is preferably in the range of 0.2 to 3.0, more preferably in the range of 0.5 to 2.0 in terms of molar ratio to the phenol monomer. Use of furfural is effective in improving water resistance. When furfural is used, it is more preferable to use formaldehyde in combination. In this case, the use ratio of formaldehyde to furfural is preferably in the range of 0.1 to 20 in molar ratio.

In the present invention, furfuryl alcohol, which is a derivative of furfural, may be used instead of furfural.

The resin composition of the present invention is characterized in that the use of the above-mentioned lignin, phenols and aldehydes allows the non-volatile matter to contain at least 30% by weight or more of a component derived from a waste liquid of a grass pulp, preferably 50 to 95% by weight or more. Particularly preferably, the content is 60 to 80% by weight. Those containing less than 30% by weight of components derived from lignin of the Gramineae plant cannot achieve the object of the present invention. In addition, this content indicates the weight% of the lignin of the Gramineae plant used in the production of the resin composition, based on the nonvolatile content of the resin composition. In the resin composition of the present invention, the reaction between the lignin and the phenols and aldehydes is preferably carried out under an alkaline condition of pH 9 or more, and pH HI 0 or more. More preferably, the reaction is carried out under alkaline conditions. As the catalyst, any alkali catalyst that satisfies such pH conditions, such as oxides and hydroxides of alkali metals and alkaline earth metals, can be used.

However, it is not necessarily limited to alkaline conditions. For example, it is also possible to obtain a novolak resin composition by reacting lignin, phenol and formaldehyde in the presence of an acidic catalyst such as oxalic acid, hydrochloric acid or sulfuric acid.

The reaction of lignin with phenols and aldehydes includes a method of reacting aldehydes with a reaction product of lignin and phenols, a method of simultaneously reacting lignin with phenols and aldehydes, and a method of reacting phenols with aldehydes. Although there is a method of reacting lignin with a reaction product, a method of reacting lignin with a reaction product of a phenol and an aldehyde is particularly preferable.

As a method of reacting lignin with a reaction product of a phenol and an aldehyde, for example, there is a method using formaldehyde as the aldehyde, and an example thereof is shown below.

First, as a reaction product of the above phenols and aldehydes, the weight average molecular weight is 120 to 500, preferably 150 to 300, and the content of the methylol compound of the phenol monomer is 2 The reaction product of phenols and formaldehyde in an amount of 0% by weight or more, preferably 40% by weight or more is used. The methylol form of the phenol monomer includes monomethylol, dimethylol, and trimethylol, and the higher the content of trimethylol and then dimethylol, the more preferable. The reaction products of the above-mentioned phenols and formaldehyde are, for example, a molar ratio of formaldehyde to phenol monomer of 1.8 to 3.5 and a molar ratio of alkali metal to phenol monomer of 0.1 to 0.5; It is obtained by reacting at a temperature of 880 ° C. for 30 minutes to 2 hours.

Next, a desired resin composition is obtained by adding the reaction product of the above phenols and aldehydes to lignin and reacting at a temperature of 50 to 95 ° C for 20 minutes to 5 hours. Another example of a method of reacting lignin with a reaction product of the above-mentioned phenols and aldehydes is one using furfural as the aldehyde. One example is shown below.

First, the reaction products of the above phenols and aldehydes are as follows: the molar ratio of furfural to phenol monomer is 0.5 to 2.0, and the molar ratio of alkali metal to phenol monomer is 0.1 to 1.0. It is obtained by reacting at a temperature of 50 to 130 ° C. for 20 minutes to 5 hours.

Next, a desired resin composition is obtained by adding the reaction product of the above phenols and aldehydes to lignin and reacting at a temperature of 60 to 95 ° C for 1 to 8 hours.

The resin composition of the present invention is generally used in the form of a liquid, particularly an aqueous solution or a suspension of water, but may be used in the form of a powder by dehydration to dryness.

Among the resin compositions of the present invention, those reacted under an alkaline condition of pH 9 or more become thermosetting, preferably 150 ° C. or more, more preferably 180 ° C. to 250 ° C. It cures when heated at a temperature of C. However, it is not necessarily limited to thermosetting. For example, a resin composition (adhesive) can be cured at room temperature by adding 0.5 to 5.0 moles of alkali metal to phenol mononuclear and mixing with an organic acid ester when used. It is.

The resin composition of the present invention can be used in all applications where conventional thermosetting resins are used, such as adhesives, binders, molding materials, etc., but adhesives, especially particle boards, fiber boards, and plywood Demonstrates excellent performance as an adhesive for wood, etc. Further, the resin composition of the present invention may be used in combination with other agents such as a water repellent, a release agent, and a flame retardant. Further, the resin composition of the present invention may be used in combination with another synthetic resin such as a urea resin and a melamine resin.

Next, the board of the present invention will be described.

The board in the present invention is a board formed by mixing small pieces of a lignocellulosic substance such as wood, pulp, or vegetation, such as particle board and fiber board, with an adhesive, and applying heat and pressure. is there.

The board of the present invention preferably contains 30% by weight or more of a component derived from a lignin of a grass family. Preferably, the resin composition containing 50 to 95% by weight or more, particularly preferably 60 to 80% by weight, is 0.2 to 30% by weight on a dry weight basis with respect to the lignocellulose substance. Or〗 to 20% by weight, mixed and heated and pressed to form a plate. As the adhesive, the above-described resin composition of the present invention is preferable, but lignin itself may be used. Some wood adhesives may be used in combination.

The hot press forming of the board of the present invention may be carried out by using an ordinary hot press, but is not limited thereto. For example, a steam injection press, a high frequency press, or the like may be used.

The molding temperature is preferably from 180 to 250 ° C, more preferably from 200 to 240 ° C. If the molding temperature exceeds 250 ° C, the lignocellulosic material deteriorates, which is not preferable.

The molding time depends mainly on the target board thickness, molding temperature and the type of hot press used. The molding pressure mainly depends on the specific gravity and thickness of the target board and the type of hot press used.

The board of the present invention has mechanical strength and water resistance equal to or higher than that of a board product using a conventional phenol aldehyde resin adhesive.

In the production of the board of the present invention, additives such as a water repellent, a release agent, and a preservative may be used. These additives may be added to and mixed with the resin composition (adhesive) in advance. It may be added separately from the resin composition (adhesive) during board production.

BEST MODE FOR CARRYING OUT THE INVENTION

The reason why the resin composition of the present invention exhibits excellent performance is considered to be due to the special structure of lignin of the grass family.

Lignin other than gramineous plants such as wood has a methoxy group in the luteol position of the phenol skeleton as shown in the formula (1) or (2), while lignin of the gramineous plant is represented by the formula (3). As shown, there is no methoxy group. According to the reaction theory of phenol, phenol is said to have a reactive activity at the ortho or para position, and lignin with a phenol skeleton having no methoxy group at the ortho position is rich in reactivity It is expected to be.

In the resin composition of the present invention, the reason why phenol is preferably used in the form of a methylol in the reaction between lignin and phenol is exemplified by using trimethylol phenol, which is the most preferred of the methylols. Trimethylolphenol represented by the formula (4) is easily dehydrated and condensed with lignin to form an oligomer in which the phenol monomer represented by the formula (5) and lignin are alternately polymerized with a methylene group interposed therebetween. Moreover, the methylol groups required for the crosslinking reaction remain in the phenol skeleton. As described above, a resin composition of a type that is cured by a cross-linking reaction of a methylol group by efficiently using a small amount of phenol and formaldehyde is formed.

However, R represents lignin. Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

In the examples, lignin powder extracted from barley straw pulp waste liquid by the soda cooking method was used as the lignin of the grass family. In Comparative Examples 1 and 2, lignin powder extracted from conifer pulp waste liquid by the craft digestion method was used as wood lignin.

The measured value of the weight-average molecular weight in this example was obtained by gel filtration chromatography (manufactured by Shimadzu Corporation) for the THF (tetrahydrofuran) soluble matter after neutralizing the sample to pH 5-7 with formic acid. Using a column "Shimazu LC Column GP C-801 150" "), carrier: THF 1 cc / min, detector UV. The phenol monomer methylol content was It is represented by the area% of the molecular weight distribution chart.

Further, in order to examine the strength performance and water resistance of the resin composition of the present invention, a particle board using the resin composition of the present invention as an adhesive was manufactured.

The particle board is made of flakes with a water content of 5% obtained by cutting the building demolition material using a knife ring flaker (pal I man) with a blade of 0.6 mm. Apply 10% by weight of adhesive with a spray gun After addition, the plated hands and pine Bok Fomin grayed the forming box of 22 cm square, with a spacer size of 1 cm (target specific gravity 0. 7 g, cm3), at a pressure 50 kgf / cm ^{2 2} Manufactured by heating at a temperature of 10 ° C. for 15 minutes. The flexural strength was measured to examine the strength performance of the board, and the water absorption thickness expansion rate was measured to examine the water resistance. The flexural strength was determined by the average value of the measured values of three test pieces pressed to a size of 50 × 200 mm according to JISA 59085.5. The coefficient of expansion of the water absorption thickness was determined by the average value of the measured values of three test pieces pressed to a size of 50 × 50 mm according to JISA 5908 5.10.

Example 1

In a reaction vessel equipped with a condenser and stirrer, formalin with a molar ratio of phenol to phenol of 3 and sodium hydroxide with a molar ratio of phenol to 0.33 are reacted at 50 ° C for 40 minutes. Thus, a reaction product X of phenol and formaldehyde was obtained. The content of the methylol form of the phenol monomer in the reaction product X is 0-methylolphenol 9%, p-methylolphenol and 2,6-dimethylol 10%, 2,4-dimethylolphenol 12%, Trimethylolphenol was 30%, for a total of 61%. The weight average molecular weight was 158.

Next, the above reaction product X is added to the gramineous plant dandanin such that the ratio of the phenol in the reaction product becomes 20% by weight relative to the gramineous plant lignin, and further the concentration becomes 40% by weight. Was added thereto and reacted at 80 ° C. for 90 minutes to produce a resin composition of the present invention. In this resin composition, the ratio of the component derived from lignin of the grass family was 74% by weight.

Next, a particle board was manufactured using this resin composition as an adhesive. The bending strength of this board was 25.3 N / cm ² , and the coefficient of expansion of the water absorption thickness was 8%.

Comparative Example 1

A resin composition was produced in the same manner as in Example 1 except that wood lignin was used instead of grass lignin.

Next, a particle board was manufactured using this resin composition as an adhesive. The bending strength of this board was 14.6 N / cm ² , and the coefficient of expansion of the water absorption thickness was 23%. Example 2

In a reaction vessel equipped with a condenser and a stirrer, furfural with a molar ratio of phenol to phenol of 1.5 and sodium hydroxide with a molar ratio of 0.80 to phenol are reacted at 70 ° C for 2 hours. A reaction product Y of phenol and furfural was produced.

Next, the above reaction product Y is added to the gramineous plant dandanin such that the ratio of the phenol in the reaction product Y becomes 20% by weight with respect to the gramineous plant lignin, and further, the ag becomes 40% by weight. As described above, water was added and reacted at 80 ° C. for 3 hours to produce a resin composition of the present invention. In this resin composition, the proportion of the component derived from the lignin of the grass family was 60% by weight.

Next, a particle board was manufactured using this resin composition as an adhesive. The bending strength of this board was 15.6 N / cm ² , and the coefficient of expansion of the water absorption thickness was 11%.

Comparative Example 2

Next, a particle board was manufactured using this resin composition as an adhesive. The bending strength of this board was 5.6 NZcm ² , and the coefficient of expansion of the water absorption thickness was 65%.

Example 3

The reaction product X produced in Example 1 was added to the grass lignin such that the ratio of phenol in the reaction product X was 10% by weight with respect to the grass lignin. The reaction product Y prepared in the above is added so that the ratio of the phenol in the reaction product Y becomes 10% by weight with respect to the lignin of the grass family, and water is further added so that the concentration becomes 40% by weight. The mixture was added and reacted at 8 (TC for 2 hours) to produce a resin composition of the present invention. In this resin composition, the ratio of a component derived from a lignin derived from a gramineous plant was 67% by weight.

Next, a particle board was manufactured using this resin composition as an adhesive. The bending strength of this board was 23.1 N / cm ² , and the coefficient of expansion of the water absorption thickness was 6%.

Comparative Example 3

In a reaction vessel with a cooler and stirrer, the molar ratio of phenol to phenol Formalin 2 and sodium hydroxide having a molar ratio to phenol of 0.33 were reacted at 80 ° C for 3.5 hours to produce a phenol aldehyde resin composition having a weight average molecular weight of 950. This resin composition corresponds to a standard board adhesive. Next, a particle board was manufactured using this resin composition as an adhesive. The flexural strength of this board was 19.6 NZ cm ² ′ and the coefficient of expansion of the water absorption thickness was 13%. Industrial applicability

According to the present invention, the following effects can be obtained.

(1) The resin composition of the present invention exhibits excellent strength performance equal to or higher than that of a conventional phenol aldehyde resin.

(2) The resin composition of the present invention exhibits excellent water resistance equal to or higher than that of a conventional phenol aldehyde resin.

(3) The resin composition of the present invention is economically advantageous because it has a high ratio of lignin and can be produced at a lower raw material cost than conventional phenolaldehyde resins.

(4) The resin composition of the present invention exhibits particularly excellent strength performance as an adhesive for lignocellulosic substances such as particle board, fiber board, and plywood.

(5) The resin composition of the present invention exhibits particularly excellent water resistance as an adhesive for lignocellulosic substances such as particle board, fiber board, and plywood.

(6) The board of the present invention has excellent mechanical strength.

(7) The board of the present invention has excellent water resistance.

(8) The resin composition of the present invention solves the problem of environmental pollution due to pulp waste liquid.

(9) In addition, resources can be used effectively.

(10) The board of the present invention is economically advantageous because a lignocellulosic board can be produced at a low raw material cost.

(11) The board of the present invention is safe for the human body since the amount of formaldehyde used is extremely small or not used at all as compared with the conventional wood bonding. is there.

Claims

The scope of the claims

1. A resin composition comprising a reaction composition of lignin with phenols and aldehydes, wherein 30% by weight or more of non-volatile components are components derived from lignin of the grass family.

2. Formaldehyde is used as at least 30% by weight or more as the aldehydes, and formaldehyde is used in a molar ratio to the phenol monomer in the range of 0.2 to 5.0. The resin composition according to 1.

3. It is a reaction product of lignin with phenols and formaldehyde under alkaline conditions of pH 9 or more, and formaldehyde is used in a molar ratio to phenol monomer in the range of 1.8 to 3.5. The resin composition according to claim 2, wherein the resin composition is prepared.

4. The weight-average molecular weight is from 120 to 500 and the non-volatile content is not less than 20% by weight. 4. The resin composition according to claim 3, wherein:

5. The reaction product of the above-mentioned phenols and formaldehyde has a weight average molecular weight of 150 to 300, and 40% by weight or more of nonvolatile components is a methylol derivative of a phenol monomer. Item 6. The resin composition according to Item 4.

6. The aldehydes, wherein furfural is used in an amount of at least 10% by weight or more, and furfural is used in a molar ratio to the phenol monomer in the range of 0.2 to 3.0. 6. The resin composition according to any one of 1 to 5.

7. The resin composition according to claim 6, wherein a reaction product of phenols and furfural under an alkaline condition of pH 9 or more is reacted with lignin.

8. A resin composition, which is a reaction product of lignin with phenols and furfuryl alcohol, wherein 30% by weight or more of non-volatile components is derived from lignin of the grass family.

9. A board formed by heating and pressurizing a lignocellulose material, wherein a resin composition in which 30% by weight or more of non-volatile components is derived from a lignin plant is dry-laid on the lignocellulose material. A board characterized by being added in an amount of 0.2 to 30% by weight.

10. The board according to claim 9, wherein the board is formed by heating and pressing at a temperature of 0.180 to 250 ° C.

11. The board according to claim 9, wherein the resin composition is a reaction product of lignin with phenols and aldehydes under an alkaline condition of pH 9 or more.

12. The resin composition is characterized in that formaldehyde is used at least 30% by weight or more as aldehydes, and the molar ratio of formaldehyde to phenol monomer is 1.2 to 5.0. The board according to claim 11, wherein

13. The resin composition has a weight-average molecular weight of 120 to 500 and a non-volatile content of not less than 20% is a reaction product of a phenol with a methylol derivative of phenol monomer and formaldehyde. 13. The board according to claim 12, wherein the board is reacted with lignin.

14. The resin composition contains at least 10% by weight of furfural as the aldehyde, and the furfural is used in a molar ratio to the phenol monomer in the range of 0.2 to 3.0. Claims characterized in that

11 The board described in 1.

15. The resin composition according to claim 14, wherein the resin composition is obtained by reacting a reaction product of phenols and furfural under a reaction condition of pH 9 or more with lignin. board.