JP7076049B1 - Wood Adhesive Compositions, Wood Adhesive Kits, Wood Materials and Their Manufacturing Methods - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition for wood capable of exhibiting sufficient adhesive strength even at cold pressure or hot pressure at a low temperature in the production of wood-based materials such as plywood. SOLUTION: A secondary reaction resol type phenol resin obtained by resolving a novolak type phenol resin, an organic acid ester, and resorcinol are contained in an adhesive composition for wood. [Selection diagram] None

Description

The present invention relates to an adhesive composition for wood, an adhesive kit for wood, a wood material, and a method for producing the same.

Conventionally, as an adhesive for adhering a wood single plate in the production of plywood, a resole-type phenol resin (alkaline phenol resin) in which phenols and aldehydes are reacted under an alkali catalyst is known.
In order to enhance the curability of the resol-type phenol resin, a curing accelerator may be added to the resol-type phenol resin. As the curing accelerator, sodium carbonate, propylene carbonate, ethylene carbonate, γ-butyl lactone, ethyl butyrate and the like are known (Patent Documents 1 to 5).

Japanese Unexamined Patent Publication No. 2000-117704 JP-A-2002-018808 Japanese Unexamined Patent Publication No. 2002-137201 Japanese Unexamined Patent Publication No. 2006-257271 Japanese Unexamined Patent Publication No. 2012-201728

However, in Patent Documents 1 to 5, although the curability of the resol type phenol resin is improved to some extent by the addition of the curing accelerator, the plywood production is carried out at a high thermal pressure temperature exceeding 100 ° C. Considering the productivity of plywood, it is desirable that it can be sufficiently cured at a lower hot pressure temperature without lengthening the hot pressure time or at cold pressure to develop sufficient adhesive strength.

INDUSTRIAL APPLICABILITY The present invention relates to an adhesive composition for wood and an adhesive kit for wood that can exhibit sufficient adhesive strength even at cold pressure or hot pressure at low temperature in the production of wood-based materials such as plywood, and sufficient adhesion even at a low hot pressure temperature. It is an object of the present invention to provide a strong wood material and a method for producing the same.

As a result of diligent studies, the present inventor has found that the above problems can be solved by combining a specific resor-type phenol resin with an organic acid ester and resorcinol, and completed the present invention.

The present invention has the following aspects.
[1] A secondary reaction resol-type phenol resin obtained by resolving a novolak-type phenol resin, an organic acid ester, and a resorcinol-containing adhesive composition for wood.
[2] The wood adhesive composition according to the above [1], wherein the organic acid ester is at least one selected from the group consisting of a lactone, a monocarboxylic acid ester, a dicarboxylic acid monoester and a dicarboxylic acid diester.
[3] The organic acid ester is a carbonate ester such as ethylene carbonate, propylene carbonate, dimethyl carbonate and the like; γ-butyrolactone, α-acetlactone, β-propiolactone, triacetin, ethylene glycol diacetate, triethylene glycol diacetate, From the group consisting of ethyl acetate, methyl butyrate, ethyl butyrate, ethyl formate, methyl salicylate, ethyl acetoacetate, dimethyl succinate, diethyl succinate, dimethyl adipate, diethyl adipate, dimethyl glutarate, diethyl glutarate and diethyl malonate. The wood adhesive composition according to the above [1] or [2], which is at least one selected.
[4] The organic acid ester contains at least one selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, γ-butyrolactone, α-acetolactone, β-propiolactone, triacetin and ethylene glycol diacetate. , The adhesive composition for wood according to any one of the above [1] to [3].
[5] Any of the above [1] to [4], wherein the content of the organic acid ester is 1.0 to 20.0 parts by mass with respect to 100 parts by mass of the secondary reaction resol type phenol resin. Adhesive composition for wood.
[6] For wood according to any one of the above [1] to [5], wherein the content of the resorcinol is 1.0 to 10.0 parts by mass with respect to 100 parts by mass of the secondary reaction resorcinol type phenol resin. Adhesive composition.
[7] The adhesive composition for wood according to any one of the above [1] to [6], wherein the pH of the secondary reaction resole-type phenol resin is 10.0 to 13.5.
[8] The adhesive composition for wood according to any one of the above [1] to [7], wherein the secondary reaction resol type phenol resin has a weight average molecular weight of 2,000 to 10,000.
[9] Secondary reaction in which the novolak-type phenol resin is resolated A first container containing the first agent containing the resol-type phenol resin, and
An adhesive kit for wood comprising a second container containing a second agent containing an organic acid ester and resorcinol.
[10] A wood-based material in which two or more woods are bonded via a cured product of the wood adhesive composition according to any one of the above [1] to [8].
[11] The wood-based material of the above [10], which is plywood.
[12] The wood-based material of the above-mentioned [10], which is a laminated lumber.
[13] Secondary reaction in which novolak-type phenol resin is resolated A step of mixing a resol-type phenol resin, an organic acid ester, and resorcinol to prepare an adhesive composition for wood.
A step of stacking a plurality of woods via the wood adhesive composition to obtain a laminate, and
A method for producing a wood-based material, which comprises a step of applying cold pressure or hot pressure to the laminate to cure the wood adhesive composition.

According to the present invention, an adhesive composition for wood capable of exhibiting sufficient adhesive strength even at cold pressure or hot pressure at low temperature in the production of wood-based materials such as plywood, and sufficient adhesive strength even at cold pressure or hot pressure at low temperature. It is possible to provide a wood-based material having the above and a method for producing the same.

A graph showing the results of Test Example 1 (horizontal axis: elapsed days, vertical axis: viscosity). The graph which shows the result of Test Example 2 (horizontal axis: ester addition amount, vertical axis: gelation time). Graphs showing the results of Examples 1 to 5 and Comparative Examples 1 to 5 (horizontal axis: resin pH, vertical axis: adhesive strength). Graphs showing the results of Examples 7 to 11 and Comparative Examples 7 to 11 (horizontal axis: F / P molar ratio, vertical axis: adhesive strength). Graphs showing the results of Examples 3, 14 to 17, and Comparative Example 14 (horizontal axis: resorcinol content, vertical axis: adhesive strength, gelation time). Graphs showing the results of Examples 3, 18 to 23 and Comparative Example 15 (horizontal axis: propylene carbonate content, vertical axis: adhesive strength, gelation time). Graphs showing the results of Examples 24 to 32 and Comparative Example 15 (horizontal axis: triacetin content, vertical axis: adhesive strength, gelation time). A graph showing the results of Test Example 3 (horizontal axis: cold pressure time, vertical axis: adhesive strength). The graph which contrasts the adhesive strength of Example 3, Comparative Examples 16, 18, and 19. The graph which contrasts the adhesive strength of Examples 27, 17, 20, 21.

In the present invention, the pH is a value at 25 ° C. unless otherwise specified.
The viscosity is a value measured by an E-type viscometer at 25 ° C.
The weight average molecular weight (hereinafter, also referred to as “Mw”) of the phenol resin (secondary reaction resol-type phenol resin, novolak-type phenol resin) is measured by gel permeation chromatography (hereinafter, also referred to as “GPC”). , Standard polystyrene conversion value.
The solid content is a non-volatile content. The non-volatile component is the residue when 1.5 g of the sample is heated at 135 ° C. for 1 hour.
A specific method for measuring the solid content concentration (nonvolatile content concentration) of the sample is shown below.
Weigh the mass C ₁ (g) of an aluminum foil dish (inner diameter 50 mm, height 15 mm), weigh the sample into 1.5 ± 0.1 g, and dry the specific mass of the sample. Let it be the previous sample mass S (g). This aluminum foil dish is placed in an incubator kept at 135 ± 1 ° C in advance, dried for 60 ± 2 minutes, allowed to cool in a desiccator, and its mass C ₂ (g) is measured. .. From the result, the sample mass D (mass of the sample remaining on the aluminum foil dish after the drying treatment) (g) after drying is calculated by the following formula (1), and the solid content concentration is calculated by the following formula (2). do.
D = C ₂ -C ₁ ... (1)
Solid content concentration (mass%) = D / S × 100 ・ ・ ・ (2)

[Adhesive composition for wood]
The wood adhesive composition according to one aspect of the present invention (hereinafter, also referred to as “the present composition”) contains a secondary reaction resole-type phenol resin, an organic acid ester, and resorcinol.
The present composition may further contain other components other than the secondary reaction resor-type phenol resin, the organic acid ester and resorcinol, if necessary.

<Secondary reaction resole-type phenol resin>
The secondary reaction resol-type phenol resin is a resin obtained by resolving a novolak-type phenol resin. Specifically, it is a reaction (secondary reaction, resol type reaction) product of a novolak type phenol resin and aldehydes in the presence of an alkaline catalyst.
The novolak-type phenol resin is a product of a reaction (primary reaction, novolak-type reaction) between phenols and aldehydes in the presence of an acid catalyst.

The novolak-type phenol resin contains a phenol condensate in which aromatic rings of two or more phenols are bonded to each other via a methylene group. In the secondary reaction, aldehydes are added to the aromatic ring of the phenol condensate to generate a methylol group, and a part of the generated methylol group reacts with another phenol condensate to increase the molecular weight. Therefore, the secondary reaction resol-type phenol resin has a methylol group and contains a phenol condensate having a higher molecular weight than the phenol condensate contained in the novolak-type phenol resin.
Secondary reaction Since the resol-type phenol resin passes through the novolak-type phenol resin, it has a lower molecular weight of trinuclear or less than the resol-type phenol resin obtained by reacting phenols and aldehydes only in the presence of an alkaline catalyst. The content of the molecular weight component is low, and the average molecular weight of the entire resin tends to be high.

Phenols are compounds having an aromatic ring and a hydroxyl group bonded to the aromatic ring, and are, for example, phenols, alkylphenols (o, m, p cresols, o, m, p ethylphenols, and xylenol isomers). Etc.), polyaromatic ring phenols (α, β naphthols, etc.), polyhydric phenols (bisphenol A, bisphenol F, bisphenol S, pyrogallol, resorcinol, catechol, hydroquinone, etc.) and the like. One of these phenols may be used alone, or two or more of them may be used in combination.
As the phenols, those other than resorcinol are preferable from the viewpoint of storage stability of the secondary reaction resol type phenol resin. Practical substances as phenols other than resorcinol are phenol, o, m, p cresols, and xylenol isomers.

The aldehydes are at least one compound selected from the group consisting of a compound having a formyl group and a multimer thereof, and examples thereof include formaldehyde, paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, salicylaldehyde, and glioxal. One of these aldehydes may be used alone, or two or more thereof may be used in combination. Of these, practical substances are formaldehyde and paraformaldehyde.

The acid catalyst used for the primary reaction is not particularly limited as long as the primary reaction proceeds. For example, inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid, oxalic acid, acetic acid, citric acid, tartrate acid, benzoic acid and paratoluene. Examples thereof include organic acids such as sulfonic acid and organic acid salts such as zinc acetate and zinc borate. One of these acid catalysts may be used alone, or two or more of them may be used in combination.

The amount of the acid catalyst used is preferably 0.05 to 2.0 parts by mass, more preferably 0.1 to 1.0 parts by mass with respect to 100 parts by mass of the phenols. When the amount of the acid catalyst used is not less than the above lower limit value, a sufficient reaction rate can be obtained, and when it is not more than the above upper limit value, the reaction can be easily controlled.
In this specification, preferable upper limit values and lower limit values can be appropriately combined. For example, the amount of the acid catalyst used may be 0.05 to 1.0 part by mass or 0.1 to 1.0 part by mass with respect to 100 parts by mass of the phenol.

The molar ratio of aldehydes / phenols (hereinafter, also referred to as “F / P molar ratio”) in the novolak type phenol resin is preferably 0.6 to 0.9, more preferably 0.7 to 0.8. When the F / P molar ratio in the novolak-type phenol resin is equal to or higher than the above lower limit, the amount of aldehydes during the resolation reaction (during the secondary reaction) can be reduced, and the heat generation during the reaction can be suppressed. If it is not more than the upper limit, gelation during the novolak reaction (during the primary reaction) can be suppressed.

The Mw of the novolak type phenol resin is preferably 1,000 to 8,000, more preferably 1,500 to 6,000. When the Mw of the novolak-type phenol resin is within the above range, the Mw of the secondary reaction resol-type phenol resin tends to be within the preferable range described later.

The alkaline catalyst used in the secondary reaction is not particularly limited as long as it can allow the secondary reaction to proceed, and various alkaline substances can be used. Specific examples include alkali metal hydroxides (sodium hydroxide, potassium hydroxide, etc.) such as sodium and potassium, alkaline earth metal oxides such as calcium, magnesium, and barium, and hydroxides, sodium carbonate, and ammonia. Inorganic alkaline substances such as; tertiary amines such as triethylamine and trimethylamine, DBU (1,8-diazabicyclo [5.4.0] undec-7-ene), DBN (1,5-diazabicyclo [4.3.0]). ] Nona-5-ene) and other organic alkaline substances such as cyclic amines; and the like. These alkaline catalysts may be used alone or in combination of two or more.

The preferable amount of the alkaline catalyst used is defined by the molar ratio of the alkaline catalyst / phenols (hereinafter, also referred to as “alkali / P molar ratio”).
The alkali / P molar ratio is preferably 0.25 to 0.45, more preferably 0.30 to 0.40. When the alkali / P molar ratio is at least the above lower limit value, a secondary reaction resole-type phenol resin can be quickly obtained, and when it is at least the above upper limit value, it is easy to control the secondary reaction.

The F / P molar ratio in the secondary reaction resole-type phenol resin is preferably 2.0 to 2.6, more preferably 2.1 to 2.5.
Here, the F / P molar ratio in the secondary reaction resole-type phenol resin is the molar ratio of the total amount of aldehydes used in the primary reaction and the secondary reaction to the phenols used in the primary reaction. Hereinafter, this molar ratio is also referred to as "final F / P molar ratio".
When the final F / P molar ratio is equal to or higher than the above lower limit, a sufficient amount of methylol groups are present in the secondary reaction resole-type phenol resin, and low molecular weight components of trinuclear bodies or less are sufficiently reduced. Therefore, the adhesive strength between woods is more excellent. When the final F / P molar ratio is not more than the above upper limit value, the amount of formaldehyde emission is small.

The weight average molecular weight (Mw) of the secondary reaction resole-type phenol resin is preferably 2,000 to 10,000, more preferably 3,000 to 10,000, still more preferably 3,000 to 9,000, and 4, 000 to 9,000 is particularly preferable, and 5,000 to 8,000 is most preferable. When the weight average molecular weight of the secondary reaction resole-type phenol resin is at least the above lower limit value, the adhesive strength between woods tends to be better, and when it is at least the above upper limit value, the viscosity of the present composition is low and the coating is applied. Workability tends to improve.
The weight average molecular weight of the secondary reaction resol-type phenol resin is preferably about 2 to 5 times the weight average molecular weight before resolation, that is, the weight average molecular weight of the novolak-type phenol resin as a raw material.

The ratio of the low molecular weight component of trinuclear body or less to the total of polynuclear bodies and mononuclear body contained in the secondary reaction resole-type phenol resin is preferably 5 area% or less, and more preferably 3 area% or less. preferable. The lower limit is not particularly limited and may be 0 area%. When the ratio of the low molecular weight component is not more than the above upper limit value, the adhesive strength between woods is more excellent.
The proportion (area%) of the low molecular weight components of trinuclear or less is the total proportion of trinuclear, dinuclear and mononuclear, and is calculated from gel permeation chromatography (GPC).
A polynuclear body means a component having two or more phenol skeletons, for example, a phenol condensate, an unreacted phenol having two or more phenol skeletons, and a methylol body having a methylol group added to the phenols. Can be mentioned. At least some of the polynuclear bodies are phenolic condensates. The trinuclear body means a component having three phenol skeletons among the polynuclear bodies. The binuclear body means a component having two phenol skeletons among the polynuclear bodies. The mononuclear body means a component having one phenol skeleton, and examples thereof include unreacted phenols having one phenol skeleton, and methylols having a methylol group added to the phenols.
The ratio of low molecular weight components of 3 nuclei or less can be adjusted by the molar ratio of phenols and aldehydes charged.

The secondary reaction resole-type phenolic resin typically contains an alkaline substance and water in addition to the phenolic condensate.
Examples of the alkaline substance include the above-mentioned alkaline catalyst.
At least some of the alkaline substances are usually alkaline catalysts used in secondary reactions. A part of the alkaline substance may be added after the secondary reaction (for example, at the time of preparation of the present composition).

The molar ratio of the alkaline substance / phenol in the secondary reaction resole-type phenol resin is preferably 0.4 to 1.0, more preferably 0.5 to 0.9, and even more preferably 0.6 to 0.8.
Here, the molar ratio of alkaline substances / phenols in the secondary reaction resole-type phenolic resin was added to the total amount of phenols used in the primary reaction with the alkaline catalyst used in the secondary reaction and after the secondary reaction. It is the molar ratio of the total amount of alkaline substances. Hereinafter, this molar ratio is also referred to as "final alkaline substance / phenolic molar ratio". When no alkaline substance is added after the secondary reaction, the total amount of the alkaline catalyst used in the secondary reaction and the alkaline substance added after the secondary reaction is the amount of the alkaline catalyst used in the secondary reaction.
If the final molar ratio of alkaline substances / phenols is above the above lower limit, the amount of free formaldehyde can be reduced without significantly increasing the molecular weight (without increasing the viscosity), and if it is below the above upper limit. , Sufficient reaction rate can be obtained and it is easy to control.

The pH of the secondary reaction resole-type phenol resin is preferably 10.0 to 13.5, more preferably 11.0 to 13.5, still more preferably 11.5 to 12.5. When the pH is at least the above lower limit value, the solubility of the secondary reaction resol type phenol resin is more excellent, and when it is at least the above upper limit value, a constant curing rate can be maintained.

The viscosity of the secondary reaction resole-type phenol resin is preferably 50 to 3,000 mPa · s, more preferably 50 to 2,000 mPa · s, further preferably 50 to 1,000 mPa · s, and 100 to 1,000 mPa · s. Is particularly preferable, and 100 to 400 mPa · s is most preferable. If the viscosity of the secondary reaction resole-type phenol resin is at least the above lower limit value, the viscosity of the present composition can be easily adjusted, and if it is at least the above upper limit value, the coatability is excellent in adhesion between woods.
The viscosity of the secondary reaction resole-type phenol resin can be adjusted by the reaction time in the secondary reaction and the like.

The solid content concentration of the secondary reaction resole-type phenol resin is preferably 20 to 60% by mass, more preferably 30 to 55% by mass. When the solid content concentration of the secondary reaction resol type phenol resin is within the above range, the viscosity of the secondary reaction resol type phenol resin is likely to be within the above-mentioned preferable range. The solid content concentration of the secondary reaction resole-type phenol resin may be further set to 35 to 55% by mass or 30 to 50% by mass.

The secondary reaction resole-type phenol resin can be produced, for example, by the method described in JP-A-2018-53131.

<Organic acid ester>
The organic acid ester functions as a curing accelerator. It is considered that the curing reaction is promoted by hydrolyzing the organic acid ester to generate an organic acid and lowering the pH of the present composition when cold pressure or hot pressure is applied.

Examples of the organic acid ester include carbonate esters such as ethylene carbonate, propylene carbonate and dimethyl carbonate; lactones such as γ-butyrolactone, α-acetolactone and β-propiolactone; triacetin, ethylene glycol diacetate and triethylene glycol di. Monocarboxylic acid esters such as acetate, ethyl acetate, methyl butyrate, ethyl butyrate, ethyl formate, methyl salicylate, ethyl acetoacetate; dimethyl succinate, diethyl succinate, dimethyl adipate, diethyl adipate, dimethyl glutarate, diethyl glutarate , Dicarboxylic acid monoesters such as diethyl malonate, or dicarboxylic acid diesters. One of these organic acid esters may be used alone, or two or more thereof may be used in combination.

As the organic acid ester, at least one selected from the group consisting of carboxylic acid esters of carbonic acid esters, lactones and polyols is preferable because of its excellent low temperature curability and relatively high boiling point. At least one selected from the group consisting of ethylene, propylene carbonate, dimethyl carbonate, γ-butyrolactone, α-acetlactone, β-propiolactone, triacetin and ethylene glycol diacetate is more preferable. Among these, at least one selected from the group consisting of propylene carbonate, γ-butyrolactone, triacetin and ethylene glycol diacetate is preferable because the curing promoting effect can be obtained in a smaller amount. If necessary, organic acid esters other than these may be used in combination.

<Other ingredients>
The other components are not particularly limited, and examples thereof include various additives and sugars.
As the additive, a component known as a constituent component of the adhesive composition for wood can be appropriately used. Examples of additives include curing accelerators, thickeners, bulking agents, viscosity modifiers and the like other than organic acid esters.
Examples of other curing accelerators include alkali metal carbonates such as sodium carbonate, sodium hydrogencarbonate, potassium carbonate, and potassium hydrogencarbonate.
Examples of the thickener include polysaccharides such as wheat flour.
Examples of the bulking agent include alkaline earth metal carbonates such as calcium carbonate.
Examples of the viscosity modifier include high boiling water-soluble organic solvents such as glycerin, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexylene glycol, and phenoxyethanol. Can be mentioned.

When the present composition contains sugars, particularly reducing sugars, it is possible to reduce the amount of formaldehyde emitted during curing of the present composition and from the cured product, and to lighten the color tone of the cured product.
The reducing sugar is not particularly limited, and may be, for example, a monosaccharide, an oligosaccharide, a dextrin, or the like. Here, "oligosaccharide" is a combination of 2 or more and 10 or less monosaccharides, and "dextrin" includes a general concept of maltodextrin and refers to a sugar composition having a DE of 20 or less.
Examples of the monosaccharide include glucose, fructose, mannose, galactose, ribose, xylose and the like.
Examples of oligosaccharides include disaccharides such as maltose, lactose and isomaltose; trisaccharides such as maltotriose; oligosaccharides having tetrasaccharides or more (for example, malto-oligosaccharides, isomalto-oligosaccharides, fructooligosaccharides, manno-oligosaccharides, galactooligosaccharides and the like). And so on.
Any one of these reducing sugars may be used alone or in combination of two or more.

<Composition of this composition>
In the present composition, the content of the organic acid ester is preferably 1.0 to 20.0 parts by mass, more preferably 1.0 to 10.0 parts by mass with respect to 100 parts by mass of the secondary reaction resol type phenol resin. .. When the content of the organic acid ester is equal to or higher than the above lower limit, when cold pressure or hot pressure is applied at a preferable temperature (25 to 80 ° C.) described later when producing a wood-based material using this composition, the present invention is used. The curability of the composition and the adhesive strength between woods tend to be better. When the content of the organic acid ester is not more than the above upper limit value, the adhesive strength between woods is more excellent when cold pressure or hot pressure is applied at the above preferable temperature, and the thickening of the present composition is suppressed and can be used. The time tends to be long.

The lower the temperature at which cold pressure or hot pressure is applied, the higher the preferable content of the organic acid ester tends to be.
When the temperature at which cold pressure or hot pressure is applied is within 70 ° C ± 10 ° C, the content of the organic acid ester is 0.1 to 10.0 mass by mass with respect to 100 parts by mass of the secondary reaction resole-type phenol resin. Parts are more preferable, 0.1 to 8.0 parts by mass are further preferable, 0.1 to 4.0 parts by mass are particularly preferable, and 0.5 to 3.0 parts by mass are most preferable.
When the temperature at the time of applying cold pressure or hot pressure is within 50 ° C. ± 10 ° C., the content of the organic acid ester is 0.1 to 15.0 mass by mass with respect to 100 parts by mass of the secondary reaction resole type phenol resin. More preferably, 0.1 to 12.0 parts by mass, particularly preferably 1.0 to 5.0 parts by mass, and most preferably 2.0 to 4.0 parts by mass.
When the temperature at the time of applying cold pressure or hot pressure is within 30 ° C. ± 10 ° C., the content of the organic acid ester is 2.0 to 20.0% by mass with respect to 100 parts by mass of the secondary reaction resole type phenol resin. More preferably, 2.0 to 17.0 parts by mass, particularly preferably 2.0 to 6.0 parts by mass, and most preferably 3.0 to 5.0 parts by mass.

The preferred content of the organic acid ester may vary depending on the temperature at which cold or hot pressure is applied, as well as the type of organic acid ester.
For example, the preferred content of propylene carbonate or γ-butyrolactone tends to be lower than the content of triacetin or ethylene glycol diacetate.
Taking the case where the temperature at the time of applying cold pressure or hot pressure is within 50 ° C. ± 10 ° C. as an example, when the organic acid ester is propylene carbonate or γ-butyrolactone, the content of the organic acid ester is secondary. 1.5 to 4.5 parts by mass is more preferable, and 2.0 to 4.0 parts by mass is further preferable with respect to 100 parts by mass of the reaction resole type phenol resin. When the organic acid ester is triacetin or ethylene glycol diacetate, the content of the organic acid ester is more preferably 2.0 to 20.0 parts by mass with respect to 100 parts by mass of the secondary reaction resole type phenol resin. It is more preferably 0 to 17.0 parts by mass, particularly preferably 2.0 to 10.0 parts by mass, and most preferably 3.0 to 8.0 parts by mass. When the organic acid ester is a mixture of dimethyl glutarate, dimethyl succinate and dimethyl adipate, the content of the organic acid ester is 4.0 to 20.0 with respect to 100 parts by mass of the secondary reaction resole-type phenolic resin. The parts by mass are more preferable, and 6.0 to 20.0 parts by mass are further preferable. When the content of the organic acid ester is at least the above lower limit value, the curability of the present composition and the adhesive strength between woods tend to be more excellent when the temperature at which cold pressure or hot pressure is applied is within the above range. There is. When the content of the organic acid ester is not more than the above upper limit value, the adhesive strength between woods is more excellent when the temperature at which cold pressure or hot pressure is applied is within the above range, and the thickening of the present composition is achieved. Is suppressed and the pot life tends to be long.

The content of resorcinol is preferably 0.5 to 10.0 parts by mass, more preferably 0.5 to 8.0 parts by mass, and 0.5 to 7. 0 parts by mass is more preferable, 0.5 to 5.5 parts by mass is even more preferable, 1.0 to 5.0 parts by mass is particularly preferable, and 1.5 to 4.5 parts by mass is most preferable. When the content of resorcinol is within the above range, the curability of the present composition and the adhesive strength between woods tend to be more excellent.

The total ratio of the solid content of the secondary reaction resole-type phenol resin to 100% by mass of the solid content of the present composition, the organic acid ester and resorcinol, is preferably 60.0% by mass or more, more preferably 70.0% by mass or more. It may be preferably 100% by mass.

The pH of the composition is preferably 10.5 to 13.5, more preferably 11.0 to 13.0. When the pH is at least the above lower limit value, the permeability to wood is good and the adhesive strength is more excellent, and when the pH is at least the above upper limit value, the curing time is sufficiently fast and the adhesive strength is also excellent.

The viscosity of the present composition is preferably 100 to 3,000 mPa · s, more preferably 500 to 2,000 mPa · s. When the viscosity of the present composition is at least the above lower limit value, sufficient adhesive strength can be maintained when temporarily adhering wood, and when it is at least the above upper limit value, the coatability of the present composition is more excellent.

The solid content concentration of the present composition is preferably 30.0 to 60.0% by mass, more preferably 35.0 to 55.0% by mass, still more preferably 40.0 to 50.0% by mass. When the solid content concentration of the present composition is within the above range, the viscosity of the present composition is likely to be within the above-mentioned preferable range.

<Preparation method of this composition>
The present composition can be prepared by mixing each of the above-mentioned components. For example, the present composition can be obtained by mixing a secondary reaction resor-type phenol resin, an organic acid ester, resorcinol, additional water or an alkaline substance if necessary, and other components.
When the secondary reaction resol type phenol resin is mixed with at least one of the organic acid ester and resorcinol, the thickening due to the gelation of the secondary reaction resol type phenol resin is likely to proceed, so that the secondary reaction resol type The phenolic resin and the organic acid ester and resorcinol are preferably mixed immediately before the production of the wood material. The time from mixing the secondary reaction resor-type phenol resin with at least one of the organic acid ester and resorcinol to applying the present composition to wood is preferably 1 hour or less.
The organic acid ester and resorcinol may be individually mixed with the secondary reaction resol type phenol resin, or may be mixed in advance before mixing with the secondary reaction resol type phenol resin. It is preferable that the organic acid ester and resorcinol are mixed in advance from the viewpoint that the manufacturing process of the wood material can be simplified.
As a method for preparing the present composition, a method of mixing the first agent and the second agent of the wood adhesive kit described later is preferable.

This composition is for wood and is used to bond wood to each other. Wood will be described in detail later. A wood-based material can be obtained by adhering two or more pieces of wood with this composition. It can be said that this composition is for producing wood-based materials.

Since this composition contains a secondary reaction resole-type phenol resin, an organic acid ester, and resorcinol, even if the hot pressure temperature is low or the cold pressure alone is relatively low in the production of wood-based materials such as plywood. Sufficient adhesive strength can be developed by taking time.
For example, conventionally, when plywood is produced using a resole-type phenol resin, the thermal pressure temperature is about 120 to 140 ° C. On the other hand, when a wood-based material such as plywood is produced using this composition, even if the thermal pressure temperature is less than 120 ° C. (for example, about 20 to 100 ° C. or about 30 to 100 ° C.), it is the same as the conventional one. It cures sufficiently in the heat pressure time of, and the adhesive strength is developed.
Therefore, according to this composition, the energy cost in the production of wood-based materials can be reduced.
The reason for achieving the above effect is that the secondary reaction resol-type phenol resin has less low molecular weight components of trinuclear bodies or less than the resol-type phenol resin in which phenols and aldehydes are reacted only with an alkali catalyst. Due to its large molecular weight, it cures relatively quickly from the beginning, and the presence of resorcinol together with the secondary reaction resole-type phenolic resin and organic acid ester further improves the reactivity, especially at low temperatures, and resorcinol. Phenol is incorporated into the skeleton of the cured product and reacts quickly, but since it is basically a monomer, it has good permeability to wood, and it is thought that it brings about a firm anchoring effect when the wood is bonded.

〔kit〕
The wood adhesive kit according to one aspect of the present invention (hereinafter, also referred to as “this kit”) includes a first container containing the first agent and a second container containing the second agent. To prepare for.

The first agent contains a secondary reaction resole-type phenol resin. The first agent is preferably free of organic acid esters and resorcinol. The first agent may further contain other components.
The secondary reaction resole-type phenol resin, the organic acid ester, and other components are as described above, and the preferred embodiments are also the same.
The pH of the first agent is preferably 11.0 to 13.5, more preferably 11.5 to 12.5.
The viscosity of the first agent is preferably 50 to 3,000 mPa · s, more preferably 50 to 2,000 mPa · s, further preferably 50 to 1,000 mPa · s, and particularly preferably 100 to 400 mPa · s.
The solid content concentration of the first agent is preferably 30.0 to 60.0% by mass, more preferably 40.0 to 55.0% by mass, and particularly preferably 40.0 to 50.0% by mass.

The second agent comprises an organic acid ester and resorcinol. The second agent preferably does not contain a secondary reaction resole-type phenol resin. The second agent may further contain other components.

The preferable content (parts by mass) of the organic acid ester in the second agent with respect to 100 parts by mass of the secondary reaction resol type phenol resin of the first agent is the organic acid with respect to 100 parts by mass of the secondary reaction resol type phenol resin in the present composition. Similar to the preferred ester content.

The preferable content (parts by mass) of resorcinol in the second agent with respect to 100 parts by mass of the secondary reaction resol-type phenol resin of the first agent is the preferable content of resorcinol in 100 parts by mass of the secondary reaction resol-type phenol resin in the present composition. Similar to quantity.

Secondary reaction to the total of 100% by mass of the solid content of the first agent and the solid content of the second agent It is the same as the preferable ratio (% by mass) of the total of the solid content of the resole-type phenol resin, the organic acid ester and resorcinol. ..

In this kit, the first agent and the second agent are mixed to form the present composition, which is used to bond woods to each other.

[Wood-based materials]
The wood-based material according to one aspect of the present invention is one in which two or more pieces of wood are bonded via a cured product of the present composition.

Examples of wood include solid wood and wood-based materials, which are typically solid wood.
Examples of the solid wood include hippo wood, paulownia wood, cedar wood, cypress wood, pine wood, hiba wood, Spanish mackerel wood, pine wood and the like. The form of solid wood may be sawn timber, sawn board, or the like.
Examples of the wood material include plywood, laminated wood, orthogonal laminated wood, single board laminated material, block board, veneer, wood board and the like. Examples of the wood board include IB (insulation board), MDF (medium density fiberboard), HB (hard board), particle board, OSB (oriented strand board) and the like.

Examples of the wood-based material of this embodiment include the same wood-based materials as those mentioned as examples of wood. As the wood material of this embodiment, plywood or laminated wood is preferable.
In the case of plywood, a plurality of wooden veneers are bonded via a cured product of the present composition. The wood veneer is not particularly limited, and a known wood veneer for plywood can be used. For example, sugi, larch and the like are preferably used as materials for wood veneer. The number of wooden veneers constituting the plywood is not particularly limited, and may be, for example, 2 to 20 sheets.
In the case of laminated wood, multiple laminas are bonded via the cured product of the present composition. Lamina is generally a cut board. The number of laminas constituting the laminated wood is not particularly limited, and may be, for example, 2 to 30 sheets.

[Manufacturing method of wood materials]
The method for producing a wood-based material according to one aspect of this aspect is
A secondary reaction in which a novolak-type phenol resin is resolated A step of mixing a resol-type phenol resin, an organic acid ester, and resorcinol to prepare an adhesive composition for wood, and a step of preparing an adhesive composition for wood.
A step of stacking a plurality of woods via the wood adhesive composition to obtain a laminate, and
It has a step of applying cold pressure or hot pressure to the laminate to cure the adhesive composition for wood.
In the step of curing the adhesive composition for wood, cold pressure may be applied and then hot pressure may be applied.
Hereinafter, the manufacturing method of this embodiment will be described by taking as an example the case of manufacturing plywood or laminated lumber as a wood material. However, the production method of this embodiment is not limited to the following examples.

<Plywood manufacturing method>
The method for producing the plywood in this example is a step of preparing the present composition by mixing a secondary reaction resol-type phenol resin obtained by resolving a novolak-type phenol resin, an organic acid ester, and resorcinol (composition preparation step). )When,
A step of stacking a plurality of veneers via the present composition to obtain a laminate (lamination step), and
A step (adhesion step) of curing the present composition by applying cold pressure only, hot pressure only, or cold pressure and hot pressure to the obtained laminate.
Have.
After the curing step, if necessary, the produced plywood may be stacked and cured for a certain period of time.

The composition preparation step is the same as the above-mentioned method for preparing the present composition.

In the laminating step, the present composition is applied to at least one surface of overlapping veneers in plywood, and a plurality of veneers are laminated. The method of applying the present composition and the method of stacking veneers may be the same as the methods used in the production of known plywood, respectively.
Examples of the coating amount of the present composition include 100 to 350 g / m ² as the mass per unit area of the laminated surface of the veneer.
In the composition preparation step, the time from mixing the secondary reaction resor-type phenol resin with at least one of the organic acid ester and resorcinol to applying the present composition to the single plate is 1 hour or less as described above. It is preferable to have.

In the bonding step, the cold pressure condition and the hot pressure condition need only be able to cure the present composition.
Examples of the cold pressure condition include a temperature: room temperature (25 ° C.), a cold pressure time: 10 to 60 minutes, and a pressure: 0.1 to 2.0 MPa.
As the thermal pressure condition, the temperature is preferably 100 ° C. or lower, more preferably 80 ° C. or lower, more preferably 20 ° C. or higher, more preferably 25 ° C. or higher, and 40 ° C. or higher in consideration of productivity. Is even more preferable. The heat pressure time is, for example, 10 to 100 seconds per 1 mm of thickness after heat pressure in the direction of applying heat pressure. The pressure is, for example, 0.1 to 2.0 MPa.
When applying hot pressure after applying cold pressure in the bonding process, the time between applying the composition to a single plate in the laminating process and applying cold pressure in the bonding process, the so-called open deposition time (so-called open deposition time). The open assembly time) is preferably 40 minutes or less. The time between applying the cold pressure and applying the hot pressure, that is, the so-called closed deposition time (closed assembly time) is preferably 3 hours or less.
After applying cold pressure or hot pressure, a treatment such as applying a load may be performed, if necessary.

<Manufacturing method of laminated wood>
The method for producing the assembly material of this example is a step of preparing the present composition by mixing a secondary reaction resol-type phenol resin obtained by resolving a novolak-type phenol resin, an organic acid ester, and resorcinol. Process) and
A step of stacking a plurality of laminas via the present composition to obtain a laminate (lamination step) and
It has a step (adhesion step) of curing the present composition by pressing the obtained laminate at room temperature for a certain period of time.
If necessary, the prepared laminated wood may be stacked and cured at a constant temperature for a certain period of time.

The composition preparation step is the same as the above-mentioned method for preparing the present composition.

In the laminating step, for example, the composition is applied to at least one laminated surface of adjacent or overlapping lamina among a plurality of lamina, and the plurality of woods are laminated with each other. The method of applying the present composition and the method of stacking wood may be the same as the methods used in the production of known laminated lumber, respectively.
Examples of the coating amount of the present composition include 100 to 350 g / m ² as the mass per unit area of the laminated surface of Lamina.
As described above, the time from the mixing of the secondary reaction resor-type phenol resin with at least one of the organic acid ester and resorcinol to the application of the present composition to the lamina in the composition preparation step is 1 hour or less. Is preferable.

Examples of the pressing conditions in the bonding step include conditions of temperature: room temperature (25 ° C.), time: 30 to 240 minutes, and pressure: 0.1 to 2.0 MPa.
The time from application of the present composition to compression, the so-called open deposition time (open assembly time), is preferably 30 minutes or less.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the examples. In each of the following examples, "part" and "%" indicate "parts by mass" and "% by mass", respectively, unless otherwise specified.

<Abbreviation>
The esters used below are shown below.
PC: Propylene carbonate.
GBL: γ-Butyrolactone.
TACN: Triacetin.
EGDA: Ethylene glycol diacetate.
TEGDA: Triethylene glycol diacetate.
DBE: Mixture of dimethyl glutarate / dimethyl succinate / dimethyl adipate = 60/20/20 (mass ratio) (Changle Yili Chemicals, China).
In the following, resorcinol may be abbreviated as Re.

<Measurement method>
(Weight average molecular weight measured by GPC)
3 g of the sample (phenolic resin) was diluted with 50 g of pure water, and the pH was adjusted to 4.0 with a 3% aqueous sulfuric acid solution while checking the pH. This is No. After filtering with the filter paper of No. 2, the filtered material was further washed with 100 g of pure water, and then air-dried to prepare a sample for GPC measurement.
The obtained GPC measurement sample was subjected to GPC measurement under the following measurement conditions, and the polystyrene-equivalent weight average molecular weight was confirmed from the results.
Column: TSKgel G3000HXL 7.8 x 300 mm x 1 (manufactured by Tosoh),
TSKgel G2000HXL 7.8 x 300 mm x 2 (manufactured by Tosoh).
Column temperature: 40 ° C.
Detector: RI (Differential Refractometer).
Solvent: THF (tetrahydrofuran).
Flow rate: 0.8 mL / min.

(viscosity)
The viscosity was measured at 25 ° C. with an E-type viscometer.

(Solid content concentration)
Weigh the mass C ₁ (g) of an aluminum foil dish (inner diameter 50 mm, height 15 mm), weigh the sample into 1.5 ± 0.1 g, and dry the specific mass of the sample. The previous sample mass S (g) was used. This aluminum foil dish was placed in an incubator kept at 135 ± 1 ° C in advance, dried for 60 ± 2 minutes, allowed to cool in a desiccator, and its mass C ₂ (g) was weighed. rice field. From the result, the sample mass D (mass of the sample remaining on the aluminum foil dish after the drying treatment) (g) after drying is calculated by the following formula (1), and the solid content concentration is calculated by the following formula (2). did.
D = C ₂ -C ₁ ... (1)
Solid content concentration (mass%) = D / S × 100 ・ ・ ・ (2)

(Gelification time (GT))
Weigh 6 g of the sample into a test tube (dimensions: inner diameter 15 mm x 150 mm), put a stirring rod in it, immerse it in an oil bath kept at a predetermined measurement temperature (120 ° C or 80 ° C), press the stopwatch, and press the stopwatch. Stir continuously with a stir bar. The time (seconds) from the immersion of the sample in the oil bath until it could not be stirred by gelation was read, and the value was taken as the gelation time (hereinafter, also referred to as "GT").

(Plywood adhesive strength)
Ten test pieces of 150 mm × 150 mm were cut out from the plywood, and each test piece was immersed in warm water at 60 ° C. for 3 hours. Then, with respect to the test piece taken out from warm water, the adhesive strength (class 2) was measured based on the test method described in the wood section of the JAS standard, and the average value was obtained. The adhesive strength (class 2) is preferably 0.7 MPa or more, more preferably 1.0 MPa or more.
In Test Example 3 and Test Example 5 described later, the 10 cut-out test pieces were further immersed in cold water for 2 hours, steamed at 130 ° C. for 2 hours, immersed in cold water for 1 hour, and again at 130 ° C. After steaming for 2 hours, the adhesive strength (special) was measured based on the test method described in the JAS standard wood edition, and the average value was calculated. The adhesive strength (special type) is preferably 0.7 MPa or more, more preferably 0.9 MPa or more, and even more preferably 1.0 MPa or more.
In the following, the adhesive strength in the examples other than Test Example 3 and Test Example 5 refers to the adhesive strength (class 2).

The gelling time and adhesive strength may vary slightly depending on the temperature and humidity at the time of measurement. Therefore, in the following, the gelling time or the adhesive strength of Examples and Comparative Examples shown in the same table were measured at almost the same timing in order to make an accurate comparison.

<Manufacturing of secondary reaction resole-type phenolic resin>
(Manufacturing Example 1: Manufacture of base resin)
517.0 parts of phenol, 264.0 parts of 50% formalin (F / P molar ratio: 0.80), 1.7 parts of 30% sulfuric acid, 93 parts of water in a 2 L flask equipped with a reflux tube, a stirrer and a thermometer. 0 parts were charged and reacted under reflux conditions for 3 hours. Then, 256.9 parts of a 30% sodium hydroxide aqueous solution (sodium hydroxide / phenol molar ratio: 0.35), 495.0 parts of 50% formalin (final F / P molar ratio: 2.30), water 173. .8 parts were added, and the mixture was reacted at 70 ° C. until the viscosity became 4,500 to 5,500 mPa · s, and cooled to 40 ° C. or lower to obtain a base resin (secondary reaction resole-type phenolic resin).
Hereinafter, the sodium hydroxide / phenol molar ratio is also referred to as “NaOH / P molar ratio”.

(Manufacturing Example 2: Production of Resin A)
To 327.0 parts of the base resin obtained in Production Example 1, 20.0 parts of 30% sodium hydroxide (final NaOH / P molar ratio: 0.50) was added, and the solid content concentration was 42.0 to 43. Water was added so as to have a concentration of 0.0% to obtain a resin A (secondary reaction resole-type phenol resin).

(Manufacturing Example 3: Production of Resin B)
To 327.0 parts of the base resin obtained in Production Example 1, 33.3 parts of 30% sodium hydroxide (final NaOH / P molar ratio: 0.60) was added, and the solid content concentration was 42.0 to 43. Water was added so as to have a concentration of 0.0% to obtain a resin B (secondary reaction resole-type phenol resin).

(Manufacturing Example 4: Production of Resin C)
To 327.0 parts of the base resin obtained in Production Example 1, 46.7 parts of 30% sodium hydroxide (final NaOH / P molar ratio: 0.70) was added, and the solid content concentration was 42.0 to 43. Water was added so as to have a concentration of 0.0% to obtain a resin C (secondary reaction resole-type phenol resin).

(Manufacturing Example 5: Production of Resin D)
To 327.0 parts of the base resin obtained in Production Example 1, 60.0 parts of 30% sodium hydroxide (final NaOH / P molar ratio: 0.80) was added, and the solid content concentration was 42.0 to 43. Water was added so as to have a concentration of 0.0% to obtain a resin D (secondary reaction resole-type phenol resin).

(Manufacturing Example 6: Production of Resin E)
To 327.0 parts of the base resin obtained in Production Example 1, 73.3 parts of 30% sodium hydroxide (final NaOH / P molar ratio: 0.90) was added, and the solid content concentration was 42.0 to 43. Water was added so as to have a concentration of 0.0% to obtain a resin E (secondary reaction resole-type phenol resin).

(Manufacturing Example 7: Manufacture of Resin F)
258.5 parts of phenol, 132.0 parts of 50% formalin (F / P molar ratio: 0.80), 0.9 parts of 30% sulfuric acid, 46 parts of water in a 1 L flask equipped with a reflux tube, a stirrer and a thermometer. Five parts were charged and reacted under reflux conditions for 3 hours. Then, 128.5 parts of a 30% sodium hydroxide aqueous solution (NaOH / P molar ratio: 0.35), 214.5 parts of 50% formalin (final F / P molar ratio: 2.10), and 75.4 parts of water. Parts are added and reacted at 70 ° C. until the viscosity reaches 4,500 to 5,500 mPa · s to obtain 128.5 parts of 30% sodium hydroxide (final NaOH / P molar ratio: 0.70). Water was added so that the solid content concentration was 42.0 to 43.0%, and resin F (secondary reaction resole-type phenol resin) was obtained.

(Manufacturing Example 8: Production of Resin G)
258.5 parts of phenol, 132.0 parts of 50% formalin (F / P molar ratio: 0.80), 0.9 parts of 30% sulfuric acid, 46 parts of water in a 1 L flask equipped with a reflux tube, a stirrer and a thermometer. Five parts were charged and reacted under reflux conditions for 3 hours. Then, 128.5 parts of 30% sodium hydroxide aqueous solution (NaOH / P molar ratio: 0.35), 231.0 parts of 50% formalin (final F / P molar ratio: 2.20), water 81.2. Parts are added and reacted at 70 ° C. until the viscosity reaches 4,500 to 5,500 mPa · s to obtain 128.5 parts of 30% sodium hydroxide (final NaOH / P molar ratio: 0.70). Water was added so that the solid content concentration was 42.0 to 43.0%, and resin G (secondary reaction resole-type phenolic resin) was obtained.

(Manufacturing Example 9: Manufacture of Resin H)
258.5 parts of phenol, 132.0 parts of 50% formalin (F / P molar ratio: 0.80), 0.9 parts of 30% sulfuric acid, 46 parts of water in a 1 L flask equipped with a reflux tube, a stirrer and a thermometer. Five parts were charged and reacted under reflux conditions for 3 hours. Then, 128.5 parts of 30% sodium hydroxide aqueous solution (NaOH / P molar ratio: 0.35), 264.0 parts of 50% formalin (final F / P molar ratio: 2.40), water 92.8. Parts are added and reacted at 70 ° C. until the viscosity reaches 4,500 to 5,500 mPa · s to obtain 128.5 parts of 30% sodium hydroxide (final NaOH / P molar ratio: 0.70). Water was added so that the solid content concentration was 42.0 to 43.0%, and resin H (secondary reaction resole-type phenolic resin) was obtained.

(Manufacturing Example 10: Production of Resin I)
258.5 parts of phenol, 132.0 parts of 50% formalin (F / P molar ratio: 0.80), 0.9 parts of 30% sulfuric acid, 46 parts of water in a 1 L flask equipped with a reflux tube, a stirrer and a thermometer. Five parts were charged and reacted under reflux conditions for 3 hours. Then, 128.5 parts of a 30% sodium hydroxide aqueous solution (NaOH / P molar ratio: 0.35), 280.5 parts of 50% formalin (final F / P molar ratio: 2.50), and 98.6 parts of water. Parts are added and reacted at 70 ° C. until the viscosity reaches 4,500 to 5,500 mPa · s to obtain 128.5 parts of 30% sodium hydroxide (final NaOH / P molar ratio: 0.70). Water was added so that the solid content concentration was 42.0 to 43.0%, and resin I (secondary reaction resole-type phenolic resin) was obtained.

(Manufacturing Example 11: Manufacture of Resin J)
258.5 parts of phenol, 132.0 parts of 50% formalin (F / P molar ratio: 0.80), 0.9 parts of 30% sulfuric acid, 46 parts of water in a 1 L flask equipped with a reflux tube, a stirrer and a thermometer. Five parts were charged and reacted under reflux conditions for 3 hours. Then, 180.0 parts of 30% potassium hydroxide aqueous solution (KOH / P molar ratio: 0.35), 247.5 parts of 50% formalin (final F / P molar ratio: 2.30), water 87.0. Parts are added and reacted at 70 ° C. until the viscosity reaches 4,500 to 5,500 mPa · s, and 180.0 parts of 30% potassium hydroxide (final KOH / P molar ratio: 0.70) is added. Water was added so that the solid content concentration was 42.0 to 43.0%, and resin J (secondary reaction resol type phenol resin) was obtained.

<Manufacturing of resole-type phenolic resin>
(Manufacturing Example 12: Production of Resin K)
94.0 parts of phenol, 139.2 parts of 50% formalin (F / P molar ratio: 2.32), 59.9 parts of 48% sodium hydroxide aqueous solution, in a 1 L flask equipped with a reflux tube, a stirrer, and a thermometer. 73.8 parts of water was charged, reacted at 90 ° C. until the viscosity became 140 mPa · s, and cooled to 40 ° C. or lower. Then, water was added so that the solid content concentration became 44.0% to obtain a resin K (resole-type phenol resin).

<Manufacturing of secondary reaction resole-type phenolic resin>
(Manufacturing Example 13: Production of Resin L)
258.5 parts of phenol, 132.0 parts of 50% formalin (F / P molar ratio: 0.80), 0.9 parts of 30% sulfuric acid, and 18. 0 parts were charged and reacted under reflux conditions for 3 hours. Then, 96.4 parts of 48% sodium hydroxide aqueous solution (NaOH / P molar ratio: 0.35), 231.0 parts of 50% formalin (final F / P molar ratio: 2.20), water 31.5. Parts are added and reacted at 65 ° C. until the viscosity reaches 7,500 to 8,500 mPa · s to add 96.4 parts of 48% sodium hydroxide (final NaOH / P molar ratio: 0.70). Addition was made to obtain resin L (secondary reaction resole-type phenolic resin).

(Manufacturing Example 14: Manufacture of Resin M)
258.5 parts of phenol, 132.0 parts of 50% formalin (F / P molar ratio: 0.80), 0.9 parts of 30% sulfuric acid, and 18. 0 parts were charged and reacted under reflux conditions for 3 hours. Then, 96.4 parts of 48% sodium hydroxide aqueous solution (NaOH / P molar ratio: 0.35), 247.5 parts of 50% formalin (final F / P molar ratio: 2.30), water 33.8. Parts are added and reacted at 65 ° C. until the viscosity reaches 7,500 to 8,500 mPa · s to add 96.4 parts of 48% sodium hydroxide (final NaOH / P molar ratio: 0.70). Addition was made to obtain resin M (secondary reaction resole-type phenolic resin).

(Manufacturing Example 15: Production of Resin N)
258.5 parts of phenol, 132.0 parts of 50% formalin (F / P molar ratio: 0.80), 0.9 parts of 30% sulfuric acid, and 18. 0 parts were charged and reacted under reflux conditions for 3 hours. Then, 96.4 parts of 48% sodium hydroxide aqueous solution (NaOH / P molar ratio: 0.35), 264.0 parts of 50% formalin (final F / P molar ratio: 2.40), water 36.0. Parts are added and reacted at 65 ° C. until the viscosity reaches 7,500 to 8,500 mPa · s, and 96.4 parts of 48% sodium hydroxide (final NaOH / P molar ratio: 0.70) is added. A resin N (secondary reaction resole-type phenolic resin) was obtained.

(Manufacturing Example 16: Production of Resin O)
258.5 parts of phenol, 132.0 parts of 50% formalin (F / P molar ratio: 0.80), 0.9 parts of 30% sulfuric acid, and 18. 0 parts were charged and reacted under reflux conditions for 3 hours. Then, 96.4 parts of a 48% sodium hydroxide aqueous solution (NaOH / P molar ratio: 0.35), 280.5 parts of 50% formalin (final F / P molar ratio: 2.50), and 38.3 parts of water. Parts are added and reacted at 65 ° C. until the viscosity reaches 7,500 to 8,500 mPa · s to add 96.4 parts of 48% sodium hydroxide (final NaOH / P molar ratio: 0.70). Addition was performed to obtain resin O (secondary reaction resole-type phenolic resin).

Tables 1 and 2 show the final F / P molar ratio, final NaOH / P molar ratio or KOH / P molar ratio, pH, weight average molecular weight, viscosity, and gelation time at 120 ° C. of the resins A to O. , Indicates the solid content concentration.

<Test Example 1>
In this test, the effect of the addition of resorcinol on the change in resin viscosity over time was verified.
100 parts of the resin C and 3 parts of resorcinol were mixed, and the obtained mixture was allowed to stand at 25 ° C. Separately, the resin C was allowed to stand at 25 ° C. as it was.
The viscosities of each of the mixture and the resin C were measured every day from the start of standing. The results are shown in FIG. FIG. 1 is a graph in which the number of days elapsed from the start of standing still is on the horizontal axis and the viscosity is on the vertical axis.
As shown in FIG. 1, when resorcinol (Re) was added, the rate of increase in resin viscosity increased, and it can be seen that resorcinol promoted gelation of the resin.

<Test Example 2>
In this test, the effect of ester addition on gelation time was verified.
To 100 parts of the resin C, 7 parts of a 50% resorcinol (Re) aqueous solution was added, and a predetermined amount (part) of the ester was further mixed, and the gelation time of the obtained mixture was measured at 80 ° C. As the organic acid ester, PC, GBL, TACN, EGDA, TEGDA or DBE was used. The results are shown in FIG. FIG. 2 is a graph in which the amount of ester added is on the horizontal axis and the gelation time is on the vertical axis. The ester content is the ratio (parts) of the resin to 100 parts by mass of the solid content.
As shown in FIG. 2, as the amount of ester added increased, the gelation time tended to become shorter. Further, among the added esters, PC, GBL, TACN, and EGDA were found to have a shorter gelling time with a smaller amount than TEGDA and DBE, and were excellent in the curing promoting effect of the secondary reaction resolated phenol resin. ..

<Examples 1 to 6, Comparative Examples 1 to 6>
(Preparation of adhesive composition for wood)
According to the formulation shown in Table 3, a 50% aqueous solution of resorcinol (Re) and an ester (PC or GBP) were mixed with the resin (resins A to E), and the wood adhesives of Examples 1 to 6 and Comparative Examples 1 to 6 were mixed. The composition was obtained.

(Making plywood)
Using any of the wood adhesive compositions of Examples 1 to 6 and Comparative Examples 1 to 6 as the adhesive, a single plate of larch with a length of 150 mm, a width of 150 mm, and a thickness of 3.1 mm (without drying) was used. , Moisture 5-15%) was used.
Apply the adhesive to the first veneer with the following application amount, stack the second veneer so that they intersect, apply the same amount of adhesive to the second veneer, and intersect. As described above, the third veneer was laminated, and the obtained laminate was heat-pressed to obtain a plywood having a thickness of about 9 mm in 3 ply.
The time from mixing each material in the preparation of the wood adhesive composition to applying the wood adhesive composition in the production of plywood was set to 3 minutes. The time from the application of the wood adhesive composition to the application of heat pressure was 7 minutes. The molding conditions are shown below.
-Adhesive application amount: 20 g / scale angle (= 220 g / m ² ).
-Heat pressure condition: 50 ° C., heat pressure time: 10 minutes (67 seconds per 1 mm thick after heat pressure of plywood), pressure: 10 kgf / cm ² (= 1 MPa).

Table 3 shows the gelation time of the wood adhesive composition of each example at 80 ° C. and the adhesive strength of the plywood.
FIG. 3 shows a graph in which the pH of the resins used in Examples 1 to 5 and Comparative Examples 1 to 5 are plotted on the horizontal axis and the adhesive strength of the plywood is plotted on the vertical axis.

Comparing Example 1 and Comparative Example 1, Example 1 containing resorcinol (Re) was superior in the adhesive strength of the plywood. The same tendency was observed in the comparisons of Examples 2 to 6 and Comparative Examples 2 to 6.
Further, when the examples 1 to 5 were compared, the resin pH tended to be the maximum in the vicinity of 12.0 to 12.5.

<Examples 7 to 11 and Comparative Examples 7 to 11>
(Preparation of adhesive composition for wood)
According to the formulation shown in Table 4, a 50% aqueous solution of resorcinol (Re) and an ester (TACN) are mixed with the resin (resins C to J), and the wood adhesive compositions of Examples 7 to 11 and Comparative Examples 7 to 11 are used. Got

(Making plywood)
Plywood was obtained in the same manner as in Examples 1 to 6 and Comparative Examples 1 to 6 except that any of the wood adhesive compositions of Examples 7 to 11 and Comparative Examples 7 to 11 was used as the adhesive.

Table 4 shows the gelation time of the wood adhesive composition of each example at 80 ° C. and the adhesive strength of the plywood.
FIG. 4 shows graphs in Examples 7 to 11 and Comparative Examples 7 to 11 with the F / P molar ratio on the horizontal axis and the adhesive strength of the plywood on the vertical axis.

Comparing Example 7 and Comparative Example 7, Example 7 containing resorcinol (Re) was superior in the adhesive strength of the plywood. The same tendency was observed in the comparisons of Examples 8 to 11 and Comparative Examples 8 to 11.
Further, when the examples 7 to 11 were compared, the F / P molar ratio tended to be the maximum in the vicinity of 2.25 to 2.35.

<Examples 3, 14 to 17, Comparative Example 14>
(Preparation of adhesive composition for wood)
According to the formulation shown in Table 5, a 50% aqueous solution of resorcinol (Re) and PC were mixed with the resin C to obtain an adhesive composition for wood of Examples 3, 14 to 17, and Comparative Example 14.

(Making plywood)
Plywood was obtained in the same manner as in Examples 1 to 6 and Comparative Examples 1 to 6 except that the wood adhesive composition of any one of Examples 3, 14 to 17 and Comparative Example 14 was used as the adhesive.

Table 5 shows the gelation time of the wood adhesive composition of each example at 80 ° C. and the adhesive strength of the plywood.
FIG. 5 shows a graph in which the content of resorcinol in each of Examples 3, 14 to 17 and Comparative Example 14 is on the horizontal axis, the adhesive strength of plywood is on the left vertical axis, and the gelation time is on the right vertical axis. .. The content of resorcinol is a ratio (part) to 100 parts by mass of the resin C.

The wood adhesive compositions of Examples 3 and 14 to 17 exhibited adhesive strength at a heat pressure of 50 ° C.
On the other hand, the wood adhesive composition of Comparative Example 14 containing no resorcinol did not exhibit adhesive strength at a heat pressure of 50 ° C., and the veneers separated from each other when the test pieces were immersed in warm water.

<Examples 3, 18-23, Comparative Example 15>
(Preparation of adhesive composition for wood)
According to the formulation shown in Table 6, a 50% aqueous solution of resorcinol (Re) and PC were mixed with the resin C to obtain an adhesive composition for wood of Examples 3, 18 to 23 and Comparative Example 15.

(Making plywood)
Plywood was obtained in the same manner as in Examples 1 to 6 and Comparative Examples 1 to 6 except that the wood adhesive composition of any one of Examples 3, 18 to 23 and Comparative Example 15 was used as the adhesive.

Table 6 shows the gelation time of the wood adhesive composition of each example at 80 ° C. and the adhesive strength of the plywood.
FIG. 6 shows a graph in which the PC content in each of Examples 3, 18 to 23 and Comparative Example 15 is plotted on the horizontal axis, the adhesive strength is plotted on the left vertical axis, and the gelation time is plotted on the right vertical axis. The content of PC is a ratio (part) of the resin C to 100 parts by mass.

The wood adhesive compositions of Examples 3 and 18 to 23 exhibited adhesive strength at a heat pressure of 50 ° C.
On the other hand, the wood adhesive composition of Comparative Example 15 containing no PC did not exhibit adhesive strength at a heat pressure of 50 ° C., and the veneers separated from each other when the test pieces were immersed in warm water.

<Examples 24 to 32, Comparative Example 15>
(Preparation of adhesive composition for wood)
According to the formulation shown in Table 7, a 50% aqueous solution of resorcinol (Re) and TACN were mixed with the resin C to obtain an adhesive composition for wood of Examples 24 to 32 and Comparative Example 15.

(Making plywood)
Plywood was obtained in the same manner as in Examples 1 to 6 and Comparative Examples 1 to 6 except that the wood adhesive composition of any of Examples 24 to 32 and Comparative Example 15 was used as the adhesive.

Table 7 shows the gelation time of the wood adhesive composition of each example at 80 ° C. and the adhesive strength of the plywood.
FIG. 7 shows a graph in which the TACN content in each of Examples 24 to 32 and Comparative Example 15 is plotted on the horizontal axis, the adhesive strength of plywood is plotted on the left vertical axis, and the gelation time is plotted on the right vertical axis. The content of TACN is a ratio (part) of the resin C to 100 parts by mass.

The wood adhesive compositions of Examples 24 to 32 exhibited adhesive strength at a heat pressure of 50 ° C.
On the other hand, the wood adhesive composition of Comparative Example 15 containing no TACN did not exhibit adhesive strength at a heat pressure of 50 ° C., and the veneers separated from each other when the test pieces were immersed in warm water.

<Test Example 3>
In this test, the effect of cold pressure time on the adhesive strength in the production of plywood was verified.
Examples 1 to 5 and Comparative Examples except that the wood adhesive composition of Example 27 was used as the adhesive and the adhesive was applied only with cold pressure for a predetermined time without performing hot pressure. Plywood was obtained in the same manner as in 1-5. Adhesive strength (class 2 and special class) was measured for the obtained plywood.
・ Cold pressure condition: 25 ° C., 15 minutes to 4 hours, pressure: 10 kgf / cm ² (= 1 MPa)
FIG. 8 shows a graph in which the cold pressure time is taken on the horizontal axis and the adhesive strength of the plywood is taken on the vertical axis.
As shown in FIG. 8, as the cooling pressure time became longer, the adhesive strength (special) tended to improve.

<Comparative Examples 16-21>
(Preparation of adhesive composition for wood)
According to the formulation shown in Table 8, a 50% aqueous solution of resorcinol (Re) and TACN were mixed with the resin (resin C or K) to obtain the wood adhesive compositions of Comparative Examples 16 to 21.

(Making plywood)
Plywood was obtained in the same manner as in Examples 1 to 6 and Comparative Examples 1 to 6 except that the wood adhesive composition of any of Comparative Examples 16 to 21 was used as the adhesive.
Further, the same operation as in Examples 3 and 27 was performed again to obtain plywood.

Table 8 shows the gelation time of the wood adhesive composition of each example at 80 ° C. and the adhesive strength of the plywood.
FIG. 9 summarizes the adhesive strengths of the plywoods of Example 3 and Comparative Examples 16, 18 and 19.
FIG. 10 summarizes the adhesive strengths of the plywoods of Example 27 and Comparative Examples 17, 20, and 21.

Comparing Example 3 and Comparative Example 16, when the resin C was used as the resin, the example in which PC and resorcinol were combined was more than the comparative example 16 in which the amount of PC was increased without adding resorcinol. It had excellent adhesive strength. Although the same tendency as described above was observed in the comparison between Comparative Example 18 and Comparative Example 19 using the resin K, the effect of improving the adhesive strength was inferior to that of the case where the resin C was used.
In Examples 27, 17, 20 and 21 in which TACN was used instead of PC, the same tendency as in Example 3 and Comparative Examples 16, 18 and 19 was observed. Further, in Comparative Example 20 in which the resin K, TACN and resorcinol were combined, the adhesive strength was inferior to that in Comparative Example 17 in which the resin C and TACN were combined. From this, it was found that resorcinol does not have a sufficient curing promoting effect in combination with a general resor-type phenol resin and TACN.

<Test Example 4>
In this test, a block shear test of laminated lumber using hippo lumber was conducted in accordance with the Japanese Agricultural Standards.

(Preparation of laminated wood block shear test piece)
The wood adhesive composition of Example 27 and Comparative Example 17 was used as the adhesive, and a hippo material having a length of 150 mm, a width of 75 mm, and a thickness of 15 mm was used as the wood.
1.2 g of the adhesive composition was applied to both of the two pieces of wood, and the adhesive surfaces were overlapped with each other and cooled for a predetermined time to obtain a test piece for a laminated wood block shear test.
In accordance with the Japanese Agricultural Standard, block-shaped test pieces were cut out so that the adhesive area was 25 mm × 25 mm = 625 mm ² , and a total of 8 pieces were prepared.
The time from mixing each material in the preparation of the wood adhesive composition to applying the wood adhesive composition in the production of plywood was set to 3 minutes. The time from the application of the wood adhesive composition to the application of heat pressure was 7 minutes. The molding conditions are shown below.
-Adhesive application amount: 20 g / scale angle (= 220 g / m ² ).
-Cold pressure condition: 25 ° C., time: 4 hours, pressure: 13 kgf / cm ² (= 1.3 MPa).

Table 9 shows the gelation time of the wood adhesive composition of each example at 80 ° C. and the results of the block shear test (strength and xylem breaking rate). When the shear strength was 9.6 MPa or more and the xylem breaking rate was 60% or more, it was judged to be acceptable, and in other cases, it was judged to be unacceptable.

Comparing Example 27 with Comparative Example 17, Example 27 containing resorcinol (Re) had a stronger shear strength and a higher xylem breaking rate.

<Test Example 5>
In this test, a high-viscosity type resin was used, and the effect of room temperature adhesion on the adhesive strength in the production of plywood was verified.

(Preparation of adhesive composition for wood)
According to the formulation shown in Table 10, a curing agent solution in which resorcinol (Re) is dissolved in an ester (TACN) and water for adjusting the viscosity are added to and mixed with the resin (resins L to O), and the woods of Examples 33 to 36 are mixed. An adhesive composition was obtained. Separately, according to the formulation shown in Table 10, ester (TACN), water for adjusting the viscosity, and calcium carbonate were added to the resin (resins L to O) in order to match the glue ratio with the examples, and Comparative Examples 22 to 22 to Twenty-five wood adhesive compositions were obtained. The "glue ratio" means the ratio of the total amount of glue (total of resin, ester, resorcinol, water, and calcium carbonate) to the amount of resin, and is calculated by the following formula.
Calculation formula: Glue magnification = total amount of glue (parts by mass) ÷ amount of resin (parts by mass) x 100
The amount of TACN added in the comparative examples was adjusted so that the gelation times of the adhesive compositions of each example and the comparative example would be about the same.

(Making plywood)
Using the wood adhesive compositions of Examples 33 to 36 and Comparative Examples 22 to 25 as the adhesive, three veneers of larch (length 150 mm × width 150 mm × thickness 2.0 mm) were used as the veneers. Plates 1 to 3) and two veneers (sugi veneer 1 to 2) (no drying, water content 5 to 15%) of 150 mm in length × 150 mm in width × 3.0 mm in thickness were used.
An adhesive was applied to the surface of the Sugi veneer 1 with the following coating amount, and the larch veneer 1 was overlapped so as to intersect. The following amount of adhesive was applied to the back surface of the sugi veneer 1, and the larch veneers 2 were overlapped so as to intersect each other. An adhesive was applied to the back surface of the Sugi veneer 2 with the following coating amount, and the adhesive was layered on the larch veneer 3 so as to intersect. An adhesive was applied to the surface of the Sugi veneer 2 in the following coating amount, and the previously laminated larch veneer 1, Sugi veneer 2, and larch veneer 2 were laminated so as to intersect each other. The obtained laminate was pressed to obtain a plywood having a thickness of about 10 mm at 5 ply.
The time from mixing each material in the preparation of the wood adhesive composition to the application of the wood adhesive composition in the production of plywood was 2 minutes, and the adhesive was applied in 3 minutes. The time from the application of the wood adhesive composition to the application of heat pressure was set to 5 minutes. The molding conditions are shown below.
-Adhesive application amount: 20 g / scale angle (= 220 g / m ² ).
-Clamping conditions: temperature: 25 ° C., time: 30 minutes, pressure: 10 kgf / cm ² (= 1 MPa).
Table 10 shows the gelation time of the wood adhesive composition of each example at 80 ° C. and the adhesive strength (special) of the plywood.

The plywood produced at 25 ° C. for 30 minutes using the adhesives of Examples 33 to 36 exhibited excellent adhesive strength. On the other hand, the plywoods using the adhesives of Comparative Examples 22 to 25 containing no resorcinol were inferior in adhesive strength even though the gelation time was the same as that of Examples 33 to 36, respectively.

Claims (13)

A secondary reaction resol-type phenol resin obtained by resolving a novolak-type phenol resin, an organic acid ester, and a wood adhesive composition containing resorcinol. The wood adhesive composition according to claim 1, wherein the organic acid ester is at least one selected from the group consisting of a lactone, a monocarboxylic acid ester, a dicarboxylic acid monoester and a dicarboxylic acid diester. The organic acid ester is a carbonate ester such as ethylene carbonate, propylene carbonate, dimethyl carbonate and the like; γ-butyrolactone, α-acetlactone, β-propiolactone, triacetin, ethylene glycol diacetate, triethylene glycol diacetate, ethyl acetate, At least selected from the group consisting of methyl butyrate, ethyl butyrate, ethyl formate, methyl salicylate, ethyl acetoacetate, dimethyl succinate, diethyl succinate, dimethyl adipate, diethyl adipate, dimethyl glutarate, diethyl glutarate and diethyl malonate. The wood adhesive composition according to claim 1 or 2, which is one type. Claimed that the organic acid ester comprises at least one selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, γ-butyrolactone, α-acetolactone, β-propiolactone, triacetin and ethylene glycol diacetate. The wood adhesive composition according to any one of 1 to 3. The wood product according to any one of claims 1 to 4, wherein the content of the organic acid ester is 1.0 to 20.0 parts by mass with respect to 100 parts by mass of the secondary reaction resol type phenol resin. Adhesive composition. The wood adhesive according to any one of claims 1 to 5, wherein the content of the resorcinol is 1.0 to 10.0 parts by mass with respect to 100 parts by mass of the secondary reaction resor-type phenol resin. Composition. The wood adhesive composition according to any one of claims 1 to 6, wherein the pH of the secondary reaction resole-type phenol resin is 10.0 to 13.5. The wood adhesive composition according to any one of claims 1 to 7, wherein the secondary reaction resole-type phenol resin has a weight average molecular weight of 2,000 to 10,000. Secondary reaction in which novolak-type phenol resin is resolated A first container containing a first agent containing a resol-type phenol resin, and a first container.
An adhesive kit for wood comprising a second container containing a second agent containing an organic acid ester and resorcinol. A wood-based material in which a plurality of woods are bonded via a cured product of the wood adhesive composition according to any one of claims 1 to 8. The wood-based material according to claim 10, which is plywood. The wood-based material according to claim 10, which is a laminated wood. A secondary reaction in which a novolak-type phenol resin is resolated A step of mixing a resol-type phenol resin, an organic acid ester, and resorcinol to prepare an adhesive composition for wood, and a step of preparing an adhesive composition for wood.
A step of stacking a plurality of woods via the wood adhesive composition to obtain a laminate, and
A method for producing a wood-based material, which comprises a step of applying cold pressure or hot pressure to the laminate to cure the wood adhesive composition.

Images