KR101535527B1 - Manufacturing method of phenol-urea-formaldehyde co-polymerized resin adhesive - Google Patents

Abstract

(a) obtaining a basic mixed solution by adding a strong base to an aqueous phenol solution; (b) adjusting the molar ratio of formaldehyde / phenol to 1.07 to 1.23 by adding primary formalin to the basic mixed solution at a reaction temperature of 40 to 50 ° C; (c) adding urea to the reactant in step (b), raising the reaction temperature to 85 to 95 캜, and maintaining the reaction; (d) adding a second formalin to the reactant in the step (c) to adjust the molar ratio of formaldehyde / phenol to 2.1 to 2.4 and conducting a condensation reaction; And (e) cooling the reactant in step (d) to obtain a final product. The present invention also provides a method for producing a phenol-urea-formaldehyde cocondensation resin adhesive and a method for producing a fiberboard using the adhesive prepared by the method do.

Description

{Manufacturing method of phenol-urea-formaldehyde co-polymerized resin adhesive}

The present invention relates to a method for producing a phenol-urea-formaldehyde cocondensed resin adhesive and a method for producing a fiberboard using the adhesive, and more particularly, to a method for producing a phenol-urea-formaldehyde cocondensed resin adhesive by adding a specific amount of urea And a phenol-formaldehyde condensate which can maintain the formaldehyde emission amount at a much lower value than the super grade E0 (Super E0), which is the highest grade based on the KS standard, without decreasing the physical properties of the fiber board, The present invention relates to a method for producing a resin adhesive for co-condensation of urea-formaldehyde and a method for producing a fiber board using the adhesive prepared by the method.

Fiberboard is a wooden plate product manufactured by molding and thermo-compression by applying glue to wood fiber obtained by firing woody material at high temperature. It can be produced up to 2.5 ~ 35mm in thickness, And is widely used in all fields of furniture used indoors. In producing such a fiberboard, an urea-formaldehyde resin adhesive or a melamine-urea-formaldehyde co-condensation resin adhesive which is colorless, excellent in adhesive strength and low in cost is widely used. However, even after the adhesive is cured, It is known that formaldehyde is released slowly and is harmful to the human body when using the product. Particularly, since fiberboard is mainly used indoors, it is known that it affects the indoor air quality by the adhesive used in the production of fiberboard, and it has a direct effect on human health. In the world, various regulations such as regulation of formaldehyde emission of wood- And indoor air quality control law is currently being implemented in Korea. Therefore, as one of the efforts to reduce the amount of formaldehyde emission of wood-based sheet products, efforts are being made to change the components and additives of adhesives.

As a prior art related to the present invention, Korean Patent No. 10-1980-0000885 discloses that when the thermosetting phenol-formaldehyde resin is prepared, the molar ratio of formaldehyde to phenol in the aqueous reaction medium in which the metal salt of the carboxylic acid is present is about 1.7 : 1 or more to react with each other to form a resin, and adding a sufficient amount of strong acid as a catalyst to cure at a high temperature. However, by using an acidic reaction catalyst and a curing catalyst, However, Patent Citation 10-2012-0110540 discloses a method for producing a phenol resin having transparency after curing. However, after an addition reaction of phenol and formaldehyde is carried out to form an intermediate, water produced as a by- It is a hassle to remove it.

In recent years, problems related to the toxicity of formaldehyde have been emphasized, and environmental regulations have been strengthened, so that it is indispensable to manufacture and use eco-friendly lignocellulosic products with reduced formaldehyde emission.

The first object of the present invention is to limit the molar ratio of the initial formaldehyde / phenol to the formaldehyde / phenol molar ratio when the formaldehyde and the urea / phenol are condensed, to add a certain amount of urea to adjust the molar ratio of the final adhesive, Thereby lowering the manufacturing cost of the adhesive.

A second object of the present invention is to provide a novel phenol-urea-formaldehyde-based resin composition which is capable of suppressing hydrolysis due to moisture and the like in the air when ultimately suppressing the release of formaldehyde, And a method for producing a condensed resin adhesive.

A third object of the present invention is to provide a method for producing a fiberboard using the phenol-urea-formaldehyde co-condensation resin adhesive.

According to an embodiment of the present invention, there is provided a method for preparing a basic solution, comprising: (a) obtaining a basic mixed solution by adding a strong base to an aqueous phenol solution; (b) adjusting the molar ratio of formaldehyde / phenol to 1.07 to 1.23 by adding primary formalin to the basic mixed solution at a reaction temperature of 40 to 50 ° C; (c) adding urea to the reactant in step (b), raising the reaction temperature to 85 to 95 캜, and maintaining the reaction; (d) adding a second formalin to the reactant in the step (c) to adjust the molar ratio of formaldehyde / phenol to 2.1 to 2.4 and conducting a condensation reaction; And (e) cooling the reactant in step (d) to obtain an end product. The present invention also provides a method for preparing a phenol-urea-formaldehyde cocatalyst adhesive.

According to another embodiment of the present invention, 10 to 20 parts by weight of a phenol-urea-formaldehyde cocondensation resin adhesive prepared by the method of any one of claims 1 to 5, and 10 to 20 parts by weight of a curing agent, And 5 parts by weight of a binder resin.

The phenol-urea-formaldehyde cocondensed resin adhesive prepared by the present invention can simplify the process of synthesizing an adhesive to reduce the cost of producing an adhesive, and can reduce the amount of formaldehyde emission without deteriorating the physical properties of a fiberboard produced using an adhesive or an adhesive Can be used to make low fiberboard.

According to one embodiment of the present invention, a process for preparing a phenol-urea-formaldehyde cocatalyst adhesive is provided.

The manufacturing method may be concretely composed of the following steps. In step (a), a strong base is added to the phenol aqueous solution to obtain a basic mixed solution. The strong base may be sodium hydroxide or potassium hydroxide, and may be added in the form of an aqueous solution. At this time, the pH of the basic mixed solution may be adjusted to 11.5 to 12.5, preferably 11.8 to 12.2 in order to maintain the water-solubility of the adhesive, improve the hardenability, and maintain the water resistance after curing.

In step (b), the molar ratio of formaldehyde / phenol is adjusted to 1.07 to 1.23 by adding primary formalin to the basic mixed solution at a reaction temperature of 40 to 50 ° C.

In the present production method, formalin is not added at one time but is divided into primary and secondary products. The formalin may be a 35-50 wt% formaldehyde aqueous solution. To allow formaldehyde to react sufficiently at the ortho- and para-positions of the phenol reaction sites to produce an initial reactant in the form of methylol phenol, the primary formalin is slowly added over a period of several tens minutes, for example, about 25 to 35 minutes . And the reaction temperature is kept the same for about 10 minutes after the formalin addition is completed to complete the production of methylol phenol. By controlling the formaldehyde to an excess molar ratio of 1.07 to 1.23 than phenol, it is possible to increase the amount of methylol phenol which is highly reactive and to increase the reactivity with the urea in the next step.

(b) Result of the reaction of the step (b) The reaction of the phenol can be inhibited through the control of the reaction conditions such as the pH, the reaction temperature and the formalin addition method, and the reaction can proceed only to the methylolization step.

In step (c), urea is added to the reaction product of step (b), and the reaction temperature is raised to 85 to 95 캜 and maintained. When the reaction temperature is less than 85 ° C, it is difficult to cause a smooth reaction, and when the reaction temperature exceeds 95 ° C, it is difficult to control the reaction. For example, the reaction temperature is adjusted to 90 ± 2 ° C over 30 minutes and then maintained for 30 minutes. The addition of these elements can lead to the copolymerization of phenol and urea.

In step (d), the molar ratio of formaldehyde / phenol is adjusted to 2.1 to 2.4 by adding the second formalin to the reaction product of step (c), and the condensation reaction is carried out. The reaction temperature may be maintained in the same manner as in the step (c). For example, the condensation reaction is carried out while maintaining the reaction at 90 占 占 폚. By controlling the molar ratio of formaldehyde / phenol as described above, the reaction of the methylol phenol and the urea is promoted to induce a co-condensation reaction, or the unreacted element and the formaldehyde react with each other to capture unreacted formaldehyde . The viscosity of the product of step (d) corresponds to C to D when measured at 25 ± 0.5 ° C. using a Gardner bubble viscometer and is measured using a Brookfield viscometer (100 rpm, spindle # 1) The viscosity of the solution is 85 ~ 100 cP.

In step (e), the reaction product of step (d) is cooled to obtain a final product. By cooling the reaction to 25 + -5 DEG C, the reaction of the phenol-urea-formaldehyde cocondensation resin is terminated to yield the final product of desired viscosity. When using actual adhesives, it is necessary to keep the final viscosity value properly after cooling in order to smoothly apply by using a sprayer. Accordingly, the viscosity of the final product corresponds to E to F when measured at 25 ± 0.5 ° C using a Gardner bubble viscometer and has a viscosity of 125 to 140 cP as measured by a Brookfield viscometer.

The adhesive prepared according to the above-described method of controlling the reaction temperature, the reaction time, the content of the raw material and the like can be suitably used for producing the fiber board. According to an embodiment of the present invention, there is provided a method of manufacturing a fiberboard using an adhesive made by the above manufacturing method.

The method for producing a fiberboard according to an embodiment of the present invention comprises mixing 10 to 20 parts by weight of a phenol-urea-formaldehyde cocatalyst adhesive prepared by the above-described method with 100 parts by weight of a wood fiber and 1 to 5 parts by weight of a curing agent . Such a fiberboard can be manufactured, for example, to have a density of 700 kg / m ² or more, and can be manufactured by thermo-compression at a temperature of 180 ° C for 240 seconds.

Hereinafter, the present invention will be described in detail with reference to Examples and Test Examples. However, these are for the purpose of illustrating the present invention in more detail, and the scope of the present invention is not limited thereto.

Example 1 Preparation of phenol-urea-formaldehyde cocondensation resin

 99% - 12.1% by weight of a strong base aqueous solution prepared by adding 50% by weight aqueous solution to a mixed solution of 17.2% by weight of phenol and 16.6% by weight of distilled water was added to the reactor, the pH was adjusted to 12.0 ± 0.2 while stirring, and the reaction temperature was maintained at 45 ± 5 ° C .

While the same temperature range was maintained, the molar ratio of formaldehyde / phenol was adjusted to 1.23 and the same temperature (45 ± 5 ° C) was further maintained for 10 minutes by adding 18.1% by weight of primary formalin for 30 minutes.

18.8% by weight of urea was added and the reaction temperature was raised to 90 ± 2 ° C. over 30 minutes and the reaction was further continued for 30 minutes. 17.2% by weight of the secondary formalin was added to adjust the molar ratio of formaldehyde / phenol to 2.4 and the condensation reaction was carried out using a bubble viscometer until the viscosity of the reactant reached C to D while maintaining the same temperature (90 ± 2 ° C) Respectively. The phenol-urea-formaldehyde cocatalyst adhesive was prepared by rapidly cooling the reactant when the viscosity of the reactant reached C to D and adjusting the viscosity of the final product to E to F. The result of measurement of the physical properties of the adhesive was The results are shown in Table 1 below.

Example 2: Preparation of phenol-urea-formaldehyde cocondensation resin

99% - 12.0% by weight of a strong base aqueous solution prepared by adding 50% by weight aqueous solution to a mixed solution of 17.8% by weight of phenol and 16.5% by weight of distilled water was added to the reactor, the pH was adjusted to 12.0 ± 0.2 while stirring and the reaction temperature was maintained at 45 ± 5 ° C . The formaldehyde / phenol molar ratio was adjusted to 1.18 and the same temperature (45 ± 5 ° C) was further maintained for 10 minutes by adding 18.0% by weight of the primary formalin for 30 minutes while maintaining the same temperature range as described above.

18.7% by weight urea was added and the reaction temperature was raised to 90 ± 2 ° C over 30 minutes, and the reaction was further continued for 30 minutes. 17.1% by weight of the secondary formalin was added to adjust the molar ratio of formaldehyde / phenol to 2.3 and the condensation reaction was carried out using a bubble viscometer until the viscosity of the reactant reached C to D while maintaining the same temperature (90 ± 2 ° C) Respectively.

The phenol-urea-formaldehyde cocatalyst adhesive was prepared by rapidly cooling the reactant when the viscosity of the reactant reached C to D and adjusting the viscosity of the final product to E to F. The result of measurement of the physical properties of the adhesive was The results are shown in Table 1 below.

Example 3 Preparation of phenol-urea-formaldehyde cocondensation resin

99% -11.9% by weight of a strong base aqueous solution made of 50% by weight aqueous solution was added to a mixed solution of 18.5% by weight of phenol and 16.3% by weight of distilled water. The pH was adjusted to 12.0 ± 0.2 while stirring, and the reaction temperature was maintained at 45 ± 5 ° C . The formaldehyde / phenol molar ratio was adjusted to 1.13 and the same temperature (45 ± 5 ° C) was further maintained for 10 minutes by adding 17.8% by weight of the primary formalin for 30 minutes while maintaining the same temperature range.

18.5% by weight of urea was added and the reaction temperature was raised to 90 ± 2 ° C. over 30 minutes and the reaction was further continued for 30 minutes. 17.0 wt% of the secondary formalin was added to adjust the molar ratio of formaldehyde / phenol to 2.2 and the condensation reaction was carried out until the viscosity of the reaction reached C to D using a bubble viscometer while maintaining the same temperature (90 ± 2 ° C) Respectively.

The phenol-urea-formaldehyde cocatalyst adhesive was prepared by rapidly cooling the reactant when the viscosity of the reactant reached C to D and adjusting the viscosity of the final product to E to F. The result of measurement of the physical properties of the adhesive was The results are shown in Table 1 below.

Example 4 Preparation of phenol-urea-formaldehyde cocondensation resin

  99% -11.8% by weight of a strong base aqueous solution made of an aqueous solution having a concentration of 50% by weight in a mixed solution of 19.3% by weight of phenol and 16.2% by weight of distilled water was added to the reactor and the pH was adjusted to 12.0 ± 0.2 while stirring. ≪ / RTI >

The formaldehyde / phenol molar ratio was adjusted to 1.07 and the same temperature (45 ± 5 ° C) was further maintained for 10 minutes by adding 17.6% by weight of the primary formalin for 30 minutes while maintaining the same temperature range as described above.

18.3% by weight of urea was added and the reaction temperature was raised to 90 ± 2 ° C over 30 minutes and the reaction was further continued for 30 minutes. The formaldehyde / phenol molar ratio was adjusted to 2.1 by adding 16.8% by weight of the secondary formalin and the condensation reaction was carried out using the bubble viscometer until the viscosity of the reactant reached C to D while maintaining the same temperature (90 ± 2 ° C) Respectively.

The phenol-urea-formaldehyde cocatalyst adhesive was prepared by rapidly cooling the reactant when the viscosity of the reactant reached C to D and adjusting the viscosity of the final product to E to F. The result of measurement of the physical properties of the adhesive was The results are shown in Table 1 below.

≪ Comparative Example 1 > Preparation of urea-formaldehyde resin (molar ratio of formaldehyde / urea: 1.1)

In a 1 L capacity reactor, 37% -formalin 57.2% by weight was added, and the temperature was raised to 50 ± 2 ° C. The pH of formalin was adjusted to 7.5 ~ 8.0 by slowly adding 1 drop of 20% NaOH aqueous solution. The temperature was raised to 75 ± 5 ° C and 29.3% by weight of the first component was added. The temperature of the reaction was elevated to 90 + 1 < 0 > C over 10 minutes and maintained for 30 minutes to induce the methylolization of the urea. The pH of the reactant was adjusted to a range of 4.5 to 5 by adding 1 drop of 20% -formic acid aqueous solution to induce the condensation reaction of the methylolized elements. When the viscosity of the reactant was measured by a bubble viscometer and the range of C to D was reached, 13.5% by weight of the secondary component was added. When the viscosity of the reaction reached C ~ D, the reaction was cooled to room temperature and 20% Was slowly added dropwise to adjust the final pH to 8.5 +/- 0.1 to terminate the reaction, thereby preparing a urea-formaldehyde resin adhesive.

Properties of phenol-urea-formaldehyde cocondensation resins division Solids content
(%) Gelation time ¹⁾
(minute) Example Additive quantity
(weight%) One 18.8 51.3 18.0 2 18.7 51.2 18.5 3 18.5 51.3 19.2 4 18.3 51.0 19.9 Comparative Example 1 ²⁾ 100 56.4 2.3

¹⁾ : In the examples, the gelation time of the resin was measured by adding 3% by weight of 20% -K ₂ CO ₃ aqueous solution to the resin solid content

²⁾ : In Comparative Example 1, a urea-formaldehyde resin having a molar ratio of formaldehyde / urea of 1.1 was used

≪ Example 5 >

13 parts by weight of the phenol-urea-formaldehyde cocatalyst adhesive prepared in Example 1 and 3 parts by weight of a curing agent were added to 100 parts by weight of the wood fiber to prepare a fiber board. The fiberboard was produced by hot pressing for 240 seconds at 180 ℃ with a target density of 700 kg / ㎥ and a thickness of 6 mm.

Table 2 shows the physical properties of the fiber board prepared from the phenol-urea-formaldehyde cocondensed resin adhesive prepared according to the synthesis method of the present invention.

≪ Example 6 >

13 parts by weight of the phenol-urea-formaldehyde cocatalyst adhesive prepared in Example 2 and 3 parts by weight of the curing agent were added to 100 parts by weight of the wood fiber to prepare a fiber board. The fiberboard was produced by hot pressing for 240 seconds at 180 ℃ with a target density of 700 kg / ㎥ and a thickness of 6 mm.

Table 2 shows the physical properties of the fiber board prepared from the phenol-urea-formaldehyde cocondensed resin adhesive prepared according to the synthesis method of the present invention.

≪ Example 7 >

13 parts by weight of the phenol-urea-formaldehyde cocatalyst adhesive prepared in Example 3 and 3 parts by weight of a curing agent were added to 100 parts by weight of the wood fiber to prepare a fiber board. The fiberboard was produced by hot pressing for 240 seconds at 180 ℃ with a target density of 700 kg / ㎥ and a thickness of 6 mm.

Table 2 shows the physical properties of the fiber board prepared from the phenol-urea-formaldehyde cocondensed resin adhesive prepared according to the synthesis method of the present invention.

≪ Example 8 >

13 parts by weight of the phenol-urea-formaldehyde cocatalyst adhesive prepared in Example 4 and 3 parts by weight of a curing agent were added to 100 parts by weight of the wood fiber to prepare a fiber board. The fiberboard was produced by hot pressing for 240 seconds at 180 ℃ with a target density of 700 kg / ㎥ and a thickness of 6 mm.

Table 2 shows the physical properties of the fiber board prepared from the phenol-urea-formaldehyde cocondensed resin adhesive prepared according to the synthesis method of the present invention.

≪ Comparative Example 2 &

13 parts by weight of the urea-formaldehyde resin adhesive prepared in Comparative Example 1 and 3 parts by weight of a curing agent were added to 100 parts by weight of wood fiber to prepare a fiber board. The fiberboard was produced by hot pressing for 240 seconds at 180 ℃ with a target density of 700 kg / ㎥ and a thickness of 6 mm.

Physical Properties of Fiberboard Prepared with Phenol-urea-formaldehyde Cocondensable Resin Adhesive Item Density ¹⁾
(g / m 3) Peel strength ²⁾
(N / mm < 2 & 24 hours absorption thickness expansion rate ³⁾
(%) Formaldehyde
Emissions ⁴⁾
(Mg / L) Example 5 0.71 1.42 16.8 0.08 Example 6 0.72 1.40 17.0 0.08 Example 7 0.71 1.45 16.9 0.07 Example 8 0.73 1.41 17.0 0.07 Comparative Example 2 0.73 1.59 27.5 0.41

^{1), 2), 3)} : Measured according to fiber board (KS F 3200)

⁴⁾ : Measurement of formaldehyde emission of building interior materials - Measured according to the desiccator method (KS M 1998)

As shown in Table 2, although the peel strength was slightly lower than that of the fiber board produced in Examples 5 to 8 using the urea-formaldehyde adhesive used in Comparative Example 2, the peel strength was 0.6 N / mm 2 ), And the 24-hour absorption thickness expansion rate passed through the absorption thickness expansion rate standard (17% or less when the thickness was 7 mm or less) specified in KS (the element-formaldehyde resin used as a comparative example did not pass the standard) , And the amount of formaldehyde emission was much lower than that of Super E ₀ (0.3 mg / L or less), the highest KS grade.

Therefore, in the case of the phenol-urea-formaldehyde cocondensed resin adhesive prepared according to the present invention, the effect of lowering the absorption thickness expansion rate and reducing the formaldehyde emission amount was obtained without significantly lowering the peel strength as compared with the conventional adhesive.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. It will be understood that the present invention can be changed.

Claims (5)

(a) obtaining a basic mixed solution by adding a strong base to an aqueous phenol solution;
(b) adjusting the molar ratio of formaldehyde / phenol to 1.07 to 1.23 by adding primary formalin to the basic mixed solution at a reaction temperature of 40 to 50 ° C;
(c) adding urea to the reactant in step (b), raising the reaction temperature to 85 to 95 캜, and maintaining the reaction;
(d) adding a second formalin to the reactant in the step (c) to adjust the molar ratio of formaldehyde / phenol to 2.1 to 2.4 and conducting a condensation reaction; And
(e) cooling the reactant in the step (d) to obtain a final product. The method of producing a phenol-urea-formaldehyde cocondensed resin adhesive according to any one of claims 1 to 5, The method according to claim 1,
Wherein the pH of the basic solution is adjusted to 11.5 to 12.5. The method according to claim 1,
The viscosity of the product of step (d) is determined by measuring the viscosity of the phenol-urea-formaldehyde cocatalyst having a viscosity of 85 to 100 cP as measured using a Brookfield viscometer (100 rpm, spindle # 1) A method for producing a resin adhesive. The method according to claim 1,
The viscosity of the final product was measured using a Brookfield viscometer (100 rpm, spindle # 1) at 25 ± 0.5 ° C to prepare a phenol-urea-formaldehyde cocatalyst adhesive having a viscosity of 125-140 cP Way. 10 to 20 parts by weight of a phenol-urea-formaldehyde cocatalyst adhesive prepared by the method of any one of claims 1 to 4 to 100 parts by weight of a wood fiber and 1 to 5 parts by weight of a curing agent Method of manufacturing fiberboard.