WO1992019661A1

WO1992019661A1 - Cocondensed urea resin

Info

Publication number: WO1992019661A1
Application number: PCT/JP1991/000590
Authority: WO
Inventors: Yoshiyasu Yamagishi; Hiroaki Yoshida; Kinji Taki; Seinosuke Horiki
Original assignee: Nagoya Oilchemical Co., Ltd.
Priority date: 1991-04-30
Filing date: 1991-04-30
Publication date: 1992-11-12
Also published as: CA2086418A1; DE4193551T1

Abstract

A cocondensed resin produced by cocondensing urea with a polyhydric phenol for the purpose of improving a urea resin in the resistances to water, weathering and boiling and workability. Although it is difficult to cocondense urea with a polyhydric phenol, the invention enables a cocondensate resin to be readily obtained by reacting 1 mol of urea with 0.2 to 2.0 mol of a polyhydric phenol and 0.1 to 2.0 mol of an aldehyde donor under heating in a pH range of 4 to 9.

Description

Specification

Urine-based co-condensation resin

Industrial applications

The present invention relates to a urea-based co-condensation resin which is inexpensive and has remarkably improved water resistance, weather resistance, boiling resistance and workability, and the urea-based co-condensation resin is made of wood, fiber, paper, glass fiber, etc. It is useful as an adhesive or binder for organic or inorganic materials.

Conventional technology

Conventionally, urea resins used for bonding wood and the like are inferior in water resistance. To improve this, co-condensation resins obtained by co-condensing urea with melamine, phenol and the like have been provided. However, although the water resistance of these co-condensation resins was improved, the boiling resistance and weather resistance were still insufficient. For this reason, various attempts have been made to co-condensate urea with a polyvalent phenol such as resorcin.However, since the reaction rates of urea and polyvalent phenol monomers differ greatly from aldehyde, it is extremely difficult to co-condense. It has been considered difficult and it is virtually impossible to obtain a co-condensation resin of urea and polyhydric phenol.

Therefore, instead of the co-condensation resin of urea and polyhydric phenol, a mixture of urea resin and polyhydric phenol monomer (for example, Japanese Patent Publication No. 57-960) or urea resin and polyhydric phenol A resin mixture with an phenolic resin (for example, Japanese Patent Publication No. 58-234425) has been proposed. In these mixtures or resin mixtures, although water resistance and boiling resistance are improved, other modifying resins, organic / inorganic fillers, thickeners, curing agents or curing catalysts, etc. were added at the time of use. At times, depending on the components to be blended, the compatibility may be poor, the viscosity may increase, or mixing may not be possible.In some cases, the pot life after blending may be shortened, resulting in inconvenience such as poor workability. there were.

Also, a method has been proposed in which a polyhydric phenol and, if necessary, formaldehyde are added to the initial condensate of urea to carry out cocondensation (Japanese Patent Application Laid-Open No. 48-51448). However, in this method, since the initial condensate of urea is used, the amount of polyhydric phenol added is limited to 0.05 to 0.2 mol per mol of urea. The effect of co-condensation was still insufficient, and for example, there was a drawback that satisfactory performance was not obtained in boiling resistance and weather resistance.

Disclosure of the invention

According to the present invention, as a means for solving the above-mentioned conventional problems, 1 mole of urea, 0.2 to 2.0 moles of polyhydric phenol and 0.1 to 2.0 moles of aldehyde donor are converted to pH 4 A urea-based co-condensation resin characterized by being obtained by heat co-condensation in the range of 9 to 9 is proposed. Detailed description of the invention

Hereinafter, the present invention will be described in detail.

(Polyvalent X-Nol)

The polyhydric phenol of the present invention refers to one or more polyhydric phenols such as resorcinol, alkyl resorcinol, pyrogallol, catechol, alkyl catechol, dyloquinone, alkylhydroquinone, floroglucin, bisphenol, dihydroxynaphthalin and the like. Mixture powers, of these polyhydric phenols, desirably resorcin or alkylresorcin, and particularly desirably alkyl resorcin, which reacts faster with aldehydes than resorcin.

Examples of the alkyl resorcinol include 5-methyl resorcinol, 5-ethyl resorcinol, 5-propyl resorcinol, 5—n-butyl resorcinol, 4,5-dimethyl resorcinol, 2,5-dimethyl resorcinol, 4,5—j Tilresorcinol, 2,5-getylresorcinol, 4,5-dipropylresorcinol, 2,5-dipiπpyrresorcinol, 4-methyl-1-5-ethyl resorcinol, 2-methyl-1 5-ethylethylresorcinol, 2 —Methyl-5-propyl resorcinol, 2, 4, 5—trimethyl resorcinol, 2,4,5-triethyl resorcinol, etc., but above all, 5-methyl resorcinol is particularly easy to co-condensate with urea and low A co-condensation resin with urea having good thermosetting properties and excellent water resistance, weather resistance and boiling resistance can be obtained. Also, the polyvalent phenol mixture obtained by dry distillation of Estonia's polyester is inexpensive and contains a large amount of various highly reactive alkylresorcinols in addition to 5-methylresorcinol. Phenol.

(Aldehyde donor)

Aldehyde donors include formalin, formaldehyde, paraformaldehyde, trioxane, acetoaldehyde, propionaldehyde, polyoxymethylene, chloral, hexamethylenetetramine, furfural, glyoxal, n-butylaldehyde, Turnip aldehyde, benzaldehyde, acrolein, tetraoxymethylene, phenylacetaldehyde, 0-tolualdehyde, sultylaldehyde, etc., compounds having an aldehyde group or compounds that decompose to release aldehyde groups upon heating One or a mixture of two or more is exemplified.

(Complexing agent)

In the present invention, a polyhydric phenol, particularly an alkylresorcin such as 5-methylresorcin, has a remarkably high reactivity with an aldehyde, so that a complexing agent for relaxing the reaction may be added. Examples of such complexing agents include phenol of polyvalent phenol. There is a compound having a ketone group or an amide group capable of forming a complex with a thiol group, and examples thereof include acetone and thioprolactam. Among them, acetone is a preferred complexing agent. The amount of the complexing agent to be added is not particularly limited, but usually about 0.4 to 0.8 mol per 1 mol of the polyvalent phenol is desirable.

(Third component)

In the condensation reaction of the co-condensation resin of the present invention, melamine, thiourea, phenol, alkylphenol, benzoguanamine, if desired, other than the urea, polyhydric phenol, aldehyde donor and complexing agent as a third component. , Toluene, xylene, coumarone, cyclohexanone, cashew oil, tannins, dammers, shellac, rosin or rosin derivatives, petroleum resins, methanol, ethanol, isopi-panol, butanol, ethylene glycol, diethylene glycol, One or more of polyethylene glycol, glycerin, furfuryl alcohol, linseed oil, tung oil, castor oil, etc. may be added or denatured as a co-condensing agent or denaturing agent.

(Production of co-condensation resin)

To obtain the co-condensation resin of the present invention, 0.2 to 2.0 moles, preferably 0.4 to 2.0 moles of the polyhydric phenol per mole of urea and, if necessary, 0.1 to 0.1 moles of the complexing agent. 6 to 1.6 And the pH is adjusted to 4.0 to 9.0, preferably 8.0 to 8.5 with an acid or alkali, and then 0.1 to 2.0 mol of an aldehyde donor is added to the mixture. The reaction is usually heated at 75 to 80 ° C. After the reaction is completed, it is desirable to cool the reaction mixture to room temperature and adjust the pH to about 8.0.

In this case, if the polyhydric phenol is less than 0.2 mol, a large amount of unreacted urea remains in the obtained resin, and a resin having water resistance and boiling resistance cannot be obtained, or 2.0 mol or more. If it is, the stability of the obtained resin is deteriorated. Further, when the polyvalent phenol is less than 0.4 mol, unreacted urea remains in the co-condensate depending on the type of the polyvalent phenol, and the performance of the resin may be deteriorated. It is desirable that the amount of the metal added be 0.4 to 2.0 mol.

When the third component is added to the co-condensation resin of the present invention, the third component may be added to the reaction system before the condensation reaction. It may be added later.

[Formulation]

In order to prepare an adhesive, a binder, a coating agent, and the like using the co-condensation resin of the present invention, usually, an aldehyde donor 1 5 to 80 parts by weight are added and mixed.If necessary, natural rubber and its derivatives, synthetic rubber such as SBR, NBR, CR, various synthetic resins such as vinyl acetate resin, acrylic resin, urethane resin, CMC, PVA, Fillers such as starch, nika, gelatin, blood powder, walnut powder, coconut powder, flour, calcium carbonate, talc, gypsum, pigments, dyes, flame retardants, insect repellents, preservatives, and other third substances Add and mix.

[Use]

The composition containing the co-condensation resin of the present invention obtained by the above composition is applied as an adhesive, a binder, and a coating agent, and is cured at room temperature or under heat. In particular, when heated to 100 ° C. or more, it cures in an extremely short time, and forms a cured resin product having excellent adhesion to woody and fibrous materials.

Accordingly, the co-condensation resin of the present invention is made of wood such as plywood, laminated wood, particle board, corrugated cardboard, felt, non-woven fabric, fiber, paper, glass fiber, rock wool, organic matter such as ceramic fiber or carbon fiber, It can be used as an inorganic material adhesive, binder, coating agent, etc.

Unlike the conventional urea resin, the curing of the co-condensation resin of the present invention does not require the addition of an acidic curing catalyst, so that the resin is kept neutral, and the resin cured product is converted into residual acid even after a long period of use. Thus, high durability is obtained without fear of being hydrolyzed and without deteriorating the wood to be adhered. But necessary If this is the case, the addition of an acidic catalyst will not work.

Further, the co-condensation resin according to the present invention is different from the conventional urea resin due to co-condensation with a polyhydric phenol, and has water resistance and boiling resistance close to the performance of the polyhydric phenol resin such as resorcinol and alkylresorcinol, Weather resistance is obtained.

In addition, when paraformaldehyde was added as a curing agent to a resorcinol-based resin, the curing speed was too high and the pot life was short, so that hexamethylenetetramine had to be used as a curing agent. However, unlike the co-condensation resin of the present invention, the pot life when adding paraformaldehyde is 2 hours or more, and the resin cures at room temperature. Further, when heated, curing is completed in a relatively short time at a relatively low temperature of 100 to 120 ° C. Therefore, the workability of the co-condensation resin of the present invention is extremely good.

Further, in the co-condensation resin of the present invention, the density of cross-links formed between urea and aldehyde by co-condensation with polyvalent phenol: phenol decreases, the resin itself becomes soft, and the stress accompanying the curing shrinkage of the resin is reduced. And the resulting cured resin layer is less likely to crack, deform, etc., and has excellent durability.

(Example 1)

In a reaction flask, 60 parts by weight (1 mol) of urea, 62 parts by weight (0.5 mol) of 5-methylresorcin and a complexing agent were added. Then, 14.5 parts by weight (0.25 mol) of acetone was added, and the pH was adjusted to 8.0 with a 40% aqueous solution of caustic soda. Then, the mixture was stirred at 50 to 55 at a temperature of 50 to 55. 40.5 parts by weight (0.5 mol) of formalin was added dropwise over 30 minutes, and the mixture was further reacted at 75 to 85 for 90 minutes. After cooling, the pH was adjusted to 8.0 again. A co-condensation resin (sample 1) was obtained. The resin was stable at room temperature for more than a few months.

To 100 parts by weight of sample 1, 20 parts by weight of coconut husk powder as a filler and 20 parts by weight of paraformaldehyde as a hardening agent were added and mixed to prepare an adhesive, and a plywood was manufactured under the following conditions and bonded. Table 1 shows the measurement results of the force.

Composition Lauan 3-ply 1.5—3.0—1.5mm Coating amount 3 5 gr Z300X300 Hidden ²

Heat pressure 1 Okg / cnf— 105 ° C X 4 min (Table 1)

(Adhesion test: According to JAS structural plywood test method) (Example 2)

In place of 5-methylresorcin used in Example 1, 55 parts by weight (0.5 mol) of resorcinol was used, and other conditions were obtained by co-condensing under the same mixing ratio and reaction conditions as in Example 1. Using the obtained resin (sample 2), a plywood similar to that of Example 1 was prepared, and the results of an adhesive strength test are shown in Table 2.

(Table 2)

(Example 3)

Using co-condensation resin sample 1 and sample 2 used in Examples 1 and 2, 100 parts by weight of each resin and 20 parts by weight of paraform were added, and the weight ratio was 10% with respect to the unraveled hardwood chip. A considerable amount was added and mixed, and hot-pressed at 14 (TC for 2 minutes) to produce a fiber board having a thickness of 3 and a specific gravity of 0.8, and its performance is shown in Table 3.

(Comparative Example 1)

For comparison with Example 3, the normal 50% urea resin 1 The same test as in Example 3 was conducted for an adhesive prepared by adding 0.6 parts by weight of ammonium chloride as a curing agent to 100 parts by weight, and the results are shown in Table 3.

(Table 3)

Flexibility: Flexible and unchanging when bent at 20 ° from the center of a test piece of width 50 hidden and length 300 mm, 〇, broken and broken one that does not break, What was soiled was X.

(Example 4)

In a reaction flask, 60 parts by weight (1 mol) of urea, 74 parts by weight (0.5 mol) of alkylresorcin obtained by dry distillation of oil shell, and 14.5 parts by weight (0.25 part) of acetone as a complexing agent. Mol), and the pH was adjusted to 8.0 with a 40% aqueous solution of caustic soda, and then, while stirring, 370.5% formalin was added at a temperature of 50 to 52 ° C with 40.5 parts by weight.

(0.5 mol) was added dropwise over 30 minutes, and then the temperature was reduced to 80 After raising to 885 and reacting for 100 minutes, the mixture was cooled to room temperature, the pH was adjusted to 8.5, and a co-condensation resin (sample 3) was obtained. The resin was stable for more than three months at room temperature.

To 100 parts by weight of this sample, 15 parts by weight of walnut powder and 15 parts by weight of paraform were added and mixed to form an adhesive. A plywood was prepared under the same conditions as in Example 1, and the pot life and adhesion test were performed. Table 4 shows the results.

(Comparative Example 2)

For comparison with Example 4, a mixture of 80% by weight of a usual 50% urea resin and 20% by weight of a 50% alkylresorcin resin was mixed with 15 parts by weight of walnut powder and 3 parts by weight of paraform as a curing agent. The same test as in Example 4 was performed for the adhesive with the addition and adjustment of the parts, and Table 4 shows the results.

(Table 4)

(Working time: according to the test method of JISK 6480) From Examples 1 to 3, the co-condensation resin according to the present invention has good adhesion, water resistance and boiling resistance, and among the polyhydric phenols, resorcinol It can be seen that the resin using alkylresorcin has more flexibility. Example 4 also shows that the pot life is longer and the workability is better than when the urea resin and the polyvalent phenol resin are blended.

Claims

The scope of the claims

Urea-based co-condensation resin obtained by heating and reacting 1 mol of urea with 0.2 to 2.0 mol of polyhydric phenol and 0.1 to 2.0 mol of aldehyde donor in the pH range of 4 to 9