KR20170062543A

KR20170062543A - Low free formaldehyde amino resin and method for producing same

Info

Publication number: KR20170062543A
Application number: KR1020177013956A
Authority: KR
Inventors: 간 다케우치; 신스케 가리우라; 이쿠에 하마모토
Original assignee: 디아이씨 가부시끼가이샤
Priority date: 2014-11-06
Filing date: 2015-09-24
Publication date: 2017-06-07
Also published as: WO2016072167A1; CN107075059A; JP5928671B1; MY163830A; JPWO2016072167A1; KR20170142216A

Abstract

A method for producing an amino resin capable of effectively lowering the content of free formaldehyde and showing no increase in the formaldehyde content even during storage, and to provide a low-free formaldehyde amino resin obtained by the above-mentioned process. (1) a step of polycondensation reaction of an amino compound and an aldehyde in a solvent to obtain a reaction mixture containing an amino resin, (2) heating the reaction mixture in the above step to 80 to 150 ° C, A method for producing a low-free formaldehyde amino resin characterized by having a step of dissolving a low-formaldehyde amino resin and a low-boiling formaldehyde amino resin obtained by the method.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-formaldehyde amino resin,

TECHNICAL FIELD The present invention relates to an amino resin, and more particularly, to an amino resin having a reduced free formaldehyde content and a method for producing the same.

The amino resin such as urea resin, melamine resin and benzoguanamine resin which is widely used as a resin for paints and the like is a decomposition product of an unreacted component of formaldehyde used as a raw material thereof and a by- It is known that free formaldehyde is contained in an amount of about several percent by mass.

It is known that this free formaldehyde adversely affects the surface hardness and water resistance when used as a coating material, and there is also attention as a causative substance of recent sick house syndrome, so that free formaldehyde contained in the amino resin is reduced as much as possible Has become an important task.

Examples of the method for reducing free formaldehyde in the amino resin include a method of containing a compound obtained by intercalating a metal into a hydrazine derivative or a crystalline layered phosphate compound or a formalin capturing agent such as activated alumina when the composition is a coating composition (See, for example, Patent Document 1), and a method in which amino resin having a primary amine and a hydroxyl group in a molecule and having 3 or more and less than 10 carbon atoms is contained in the amino resin (see, for example, Patent Document 2) Are provided.

However, the introduction of the unreacted component into the coating composition, which is provided in Patent Document 1, sometimes affects the strength of the cured coating film, and the storage stability of the coating composition may become poor, It is hard to say that it is a solution. On the other hand, the method provided in Patent Document 2 certainly has a certain effect in that it is low-free formaldehyde as an amino resin, but the reduction effect does not reach a practical level, There is no verification as to whether the effect can be sustained.

Japanese Patent Application Laid-Open No. 2005-298694 Japanese Patent Application Laid-Open No. 11-335521

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a method for producing an amino resin capable of effectively lowering the content of free formaldehyde, and to provide a low-free formaldehyde amino resin obtained by the above process.

As a result of intensive studies, the inventors of the present invention have found that, after a step of obtaining an amino resin, the reaction mixture containing the amino resin is heated to a specific temperature range and refluxed or solvent is removed, Aldehyde, and by-products which are decomposed during storage and are likely to generate formaldehyde, thereby obtaining a low-free formaldehyde amino resin. The present invention has been accomplished on the basis of this finding.

That is, the present invention relates to a process for producing (1) a process for producing a reaction mixture comprising an amino resin by subjecting an amino compound and an aldehyde to a polycondensation reaction in a solvent,

(2) heating the reaction mixture in the above step to 80 to 150 ° C to reflux or remove the organic phase, and a process for producing a low-free formaldehyde amino resin obtained by the above- Resin.

The amino resin obtained by the production method of the present invention has extremely few free formaldehyde contained therein as compared with the conventional amino resin. Therefore, it can be suitably used as a composition for paints which can cope with the recent regulation of formaldehyde.

The amino resin produced in the present invention may be an amino resin obtained by polycondensation of an amino compound and an aldehyde, or may be an air condensate obtained by using two or more amino compounds in combination.

Examples of the amino compound include melamine, urea, benzoguanamine, acetoguanamine, spiroguanamine, cyclohexanecarbuanamine, cyclohexenecarbuanamine, benzoic acid guanamine, 2-dicyandiamide, and the like. . Among them, melamine, urea and benzoguanamine are preferably used from the viewpoint of versatility as an amino resin.

Examples of the aldehydes include polycondensation with an amino compound. Examples of the aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde and the like. From the viewpoint that the effect of the present invention is high and the versatility is excellent, formaldehyde Is preferably used.

As the amino resin, a methylated amino resin obtained by the reaction of an amino compound and an aldehyde may be etherified with an alcohol. It is preferable that some or all of the methylol groups in the methylol amino resin are etherified with alcohol from the viewpoints of the hardness of the coating film and the processability when the obtained low-free formaldehyde amino resin is used as the resin composition for paints.

The step (1) in the production method of the present invention is a step of producing a common amino resin and is not particularly limited, and the amino compound and the aldehyde described above are allowed to react in a solvent. Here, as the solvent, an alcohol is preferably contained, and it is particularly preferable to use an alcohol having 1 to 8 carbon atoms.

In the reaction of the amino-based compound and the aldehyde, it is preferable to use an acid catalyst for promoting the condensation. As the acid catalyst, it is preferable that it is dissolved uniformly in a solvent, and for example, formic acid, phosphoric acid, phthalic acid, hydrochloric acid, nitric acid, sulfuric acid and the like can be used.

The use ratio of the amino compound and the aldehyde in the step (1) is preferably 0.1 to 5.0, more preferably 0.1 to 5.0, in terms of the aldehyde group (molar ratio) in the aldehyde relative to 1.0 mole of the amino group in the amino compound from the viewpoints of workability, , And particularly preferably in the range of 0.8 to 3.2.

The timing of injecting the acid catalyst into the reaction system is not particularly limited, but from the viewpoints of workability, curability, and physical properties of the coating film, it is preferable to introduce the acid catalyst after the methylol reaction proceeds to some extent. For example, It is preferable to react the aldehydes in a solvent at 80 to 100 ° C for 0.1 to 3.0 hours and then add them.

The use ratio of the acid catalyst is preferably in the range of 0.001 to 0.1 mass% with respect to the amino compound from the viewpoint of favorable reaction and control of the functional group.

As the reaction end point of the step (1), it is possible to easily judge, for example, by measuring the Gardner viscosity and Tolerance and setting the time point to reach the target value.

As the production method of the present invention, the reaction mixture containing the amino resin obtained in the step (1) may be directly supplied to the step (2), but from the viewpoint of easily making the amino resin of the lower free formaldehyde, It is preferable to pass through the process. Although the method of the solvent is not particularly limited, it is preferably removed under a reduced pressure of about 40 to 80 Torr (5.3329 × 10 ³ to 1.0665 × 10 ⁴ Pa).

The level of the desolvation agent can be judged by the Gardner viscosity of the reaction mixture, and it is preferable to terminate at the stage where it becomes about Z1 to Z6.

Step (2) in the production method of the present invention is a step of refluxing or removing the reaction mixture obtained at 80 to 150 ° C. At this time, a reduced pressure condition is also possible.

The viscosity of the reaction mixture after the solvent removal is high, and when heated at this temperature, the temperature tends to vary in the mixture. Therefore, it is preferable to carry out the step (2) after adding a solvent capable of uniformly dissolving the reaction mixture before warming. The solvent which can be used at this time is preferably a solvent which refluxes at a temperature of from 80 to 150 ° C, which is a temperature for heating, and examples thereof include toluene, xylene, ethyl acetate, butyl acetate and methyl isobutyl ketone. Or may be used as a mixed solvent.

The use ratio in the case of using the solvent in the step (2) is not particularly limited, but it is preferable to use 0 to 200% by mass with respect to the mass of the reaction mixture in the shearing layer of the step (2) .

The heating in the step (2) is required to be 80 to 150 占 폚 as described above. When the temperature is lower than 80 ° C, it is difficult to effectively remove formaldehyde (unreacted components) and by-products from the reaction mixture, which are decomposed and are likely to become formaldehyde, so that a desired low-free formaldehyde amino resin can not be obtained . On the other hand, if the temperature exceeds 150 ° C, the amino resin tends to be deteriorated easily, and the intended molecular weight distribution of the amino resin is easily affected. The heating temperature in the step (2) is more preferably in the range of 80 to 130 占 폚.

The determination of the end point of the step (2) can be performed, for example, by measurement of free formaldehyde. As a standard, the heating time is about 0.5 to 6.0 hours.

After the step (2), the amino resin is purified (isolated). However, this method is not particularly limited, and the work performed after the synthesis of the usual amino resin can be used as it is. For example, after the reactor is cooled to room temperature, the catalyst may be adjusted as necessary to prepare the nonvolatile matter with a desired solvent.

The content of the free formaldehyde as measured by the octylamine method is 1% by mass or less, particularly 0.5% by mass or less. This value does not rise even after storage at 25 ° C for 12 months, for example, at 60% of nonvolatile content, and it is a great feature that formaldehyde as a decomposed product does not occur even by long-term storage.

The use of the low-boiling formaldehyde amino resin of the present invention is not particularly limited and can be suitably used in applications where conventional amino resins are used. For example, the composition can be used in combination with a polyester resin, an alkyd resin, and an acrylic resin, and can be used as a baking general paint.

[Example]

Hereinafter, the present invention will be further described by way of examples, but the present invention is not limited to these examples. Unless otherwise noted, parts and percentages are by weight.

Example 1

847.4 parts of n-butanol, 329.4 parts of 92% paraform, 142.3 parts of water and 230.0 parts of melamine were poured into a flask equipped with a stirrer, a temperature sensor and a decanter and heated to 93 to 98 DEG C with stirring, To 6.2. Subsequently, n-butanol refluxing reaction was carried out at 95 to 110 ° C. When the content of normal hexane toluene was 500% or more and methanol / water = 9/1 toluene was 400% or less, the reaction was stopped and a vacuum decomposition agent was carried out. When the Gardner viscosity reached Z1, the decompression was broken and 650.0 parts of xylene for industrial use was added and the solvent was removed at 120 to 140 ° C. It was confirmed that the amount of free formaldehyde was 0.1% or less, and after cooling, the nonvolatile content was adjusted to 58 to 62%. Butylated melamine resin (1) having 0.09% of free formaldehyde, 60.2% of nonvolatile matter, 1,350 of weight average molecular weight (Mn) and an acid value of 1 or less.

Example 2

900.0 parts of 92% paraform, 976.1 parts of methanol, 81.2 parts of water, 0.56 parts of 25% caustic soda aqueous solution and 400.0 parts of melamine were poured into a flask having a stirrer, a temperature sensor and a decanter and heated to 70 to 80 DEG C with stirring Methylol reaction was carried out. After 1 hour, 1000.0 parts of methanol was injected and cooled to 40 占 폚 or lower. 98% sulfuric acid was added thereto to adjust the pH to 4 or less, and the reaction was carried out at 30 to 50 ° C. When the content of 9% NaCl toluene became 200% or less, the reaction was stopped and the pH was adjusted to 10.0 to 10.5 with a 25% aqueous solution of caustic soda, followed by decompression desolvation. When the Gardner viscosity reached Z6 to Z7, the decompression was broken and 950 parts of industrial xylene was added and the solvent was removed at 130 to 140 deg. It was confirmed that the amount of free formaldehyde was 0.5% or less, and after cooling, the nonvolatile content was adjusted to 58 to 62%. Methylated melamine resin (1) having 0.3% of free formaldehyde, 60.1% of nonvolatile matter, 515 of weight average molecular weight (Mn) and an acid value of 1 or less was obtained.

Example 3

847.4 parts of n-butanol, 329.4 parts of 92% paraform, 142.3 parts of water and 230.0 parts of melamine were poured into a flask equipped with a stirrer, a temperature sensor and a decanter and heated to 93 to 98 DEG C with stirring, To 6.2. Subsequently, n-butanol refluxing reaction was carried out at 95 to 110 ° C. When the content of normal hexane toluene was 500% or more and methanol / water = 9/1 toluene was 400% or less, the reaction was stopped and a vacuum decomposition agent was carried out. When the Gardner viscosity reached Z1, the decompression was broken, 650.0 parts of xylene for industrial use was added, and the solvent was removed at 60 to 100 DEG C under a reduced pressure of 80 to 120 Torr. It was confirmed that the amount of free formaldehyde was 0.6% or less, and after cooling, the nonvolatile content was adjusted to 58 to 62%. Butylated melamine resin (2) having 0.5% of free formaldehyde, 60.2% of nonvolatile matter, 1,250 of weight average molecular weight (Mn) and an acid value of 1 or less was obtained.

Example 4

847.4 parts of n-butanol, 329.4 parts of 92% paraform, 142.3 parts of water and 230.0 parts of melamine were poured into a flask equipped with a stirrer, a temperature sensor and a decanter and heated to 93 to 98 DEG C with stirring, To 6.2. Subsequently, n-butanol refluxing reaction was carried out at 95 to 110 ° C. When the content of normal hexane toluene was 500% or more and methanol / water = 9/1 toluene was 400% or less, the reaction was stopped and a vacuum decomposition agent was carried out. When the Gardner viscosity reached Z1, the decompression was broken, 650.0 parts of xylene for industrial use was added, and the solvent was removed at 80 to 120 DEG C under a reduced pressure of 250 to 350 Torr. It was confirmed that the amount of free formaldehyde was 0.2% or less, and after cooling, the nonvolatile content was adjusted to 58 to 62%. Butylated melamine resin (3) having 0.09% of free formaldehyde, 60.2% of nonvolatile matter, a weight average molecular weight (Mn) of 1,230, a molecular weight distribution (Mw / Mn) of 3.0 and an acid value of 1 or less.

Comparative Example 1

847.4 parts of n-butanol, 329.4 parts of 92% paraform, 142.3 parts of water and 230.0 parts of melamine were poured into a flask equipped with a stirrer, a temperature sensor and a decanter and heated to 93 to 98 DEG C with stirring, To 6.2. Subsequently, n-butanol refluxing reaction was carried out at 95 to 110 ° C. When the content of normal hexane toluene was 500% or more and methanol / water = 9/1 toluene was 400% or less, the reaction was stopped and a vacuum decomposition agent was carried out. When the Gardner viscosity reached Z1, the reduced pressure was broken and the non-volatile content was adjusted to 58 to 62% with xylene after cooling. The obtained amino resin was a butylated melamine resin (4) having 3.0% of free formaldehyde, 59.8% of nonvolatile matter, 1,200 of weight average molecular weight (Mn) and an acid value of 1 or less.

Comparative Example 2

900.0 parts of 92% paraform, 976.1 parts of methanol, 81.2 parts of water, 0.56 parts of 25% caustic soda aqueous solution and 400.0 parts of melamine were poured into a flask having a stirrer, a temperature sensor and a decanter and heated to 70 to 80 DEG C with stirring Methylol reaction was carried out. After 1 hour, 1000.0 parts of methanol was injected and cooled to 40 占 폚 or lower. 98% sulfuric acid was added thereto to adjust the pH to 4 or less, and the reaction was carried out at 30 to 50 ° C. When the content of 9% NaCl toluene became 200% or less, the reaction was stopped and the pH was adjusted to 10.0 to 10.5 with a 25% aqueous solution of caustic soda, followed by decompression desolvation. When the Gardner viscosity became Z6 to Z7, the reduced pressure was broken, and after cooling, the nonvolatile content was adjusted to 58 to 62% by using xylene and isobutanol. The resulting amino resin was a methylated melamine resin (2) having 4.6% of free formaldehyde, a weight average molecular weight (Mw) of 500, and an acid value of 1 or less.

The analysis of the amino resin and the confirmation of the progress of the reaction are carried out by the following methods.

5.00 g of the sample is collected in a 100 ml Erlenmeyer flask using an upper dish scale.

Add normal hexane to the contents of the flask with buret and mix well.

The inside of the flask is accurately adjusted to 25.0 캜 with a thermometer, placed on the examination object, and viewed from the top. The sample is dropped through the liquid layer of the Erlenmeyer flask until the type becomes unreadable, and the dropping amount of the solvent is measured.

Tolerance (%) = amount of solvent used ml × 20

Add the methanol / water = 9/1 solution to the contents of the flask with buret and mix well.

Tolerance (%) = amount of solvent used ml × 20

<9% NaCl Tolerance>

Add 9% NaCl aqueous solution to the contents of the flask with buret and mix well.

Tolerance (%) = amount of solvent used ml × 20

Collect 1.50 g of the sample in a 100 ml Erlenmeyer flask with an upper dish scale.

Add 70 ml of a mixed solvent (xylene (industrial grade) / isobutyl alcohol = 1 / 1wt) to a 100 ml measuring cylinder and dissolve.

Add 10 ml of a 1 mol / L 2-ethylhexylamine mixed solution (2-ethylhexylamine / mixed solvent = 70/430 mL) with the hole pipette.

And the mixture is stirred for 1 hour.

Using a potentiometer, PH7.0 is terminated with 1 mol / L salicylic acid solution.

A blank test is conducted in this manner.

Content of free formaldehyde (%) = ((B-T) x F x 3) / S

B: Amount of the 1 mol / L salicylic acid solution used in the blank test (ml)

T: Amount of the 1 mol / L salicylic acid solution (ml)

F: Potency of 1 mol / L salicylic acid solution

S: Amount of sample (g)

&Lt; Weight average molecular weight (Mn) >

Measuring device ; HLC-8120GPC manufactured by Tosoh Corporation

Column: Made by Tosoh Co., Ltd. TSK-GUARDCOLUMN H _XL -H

+ Made by Toso Co., Ltd. TSK-GEL G5000H _XL

+ Made by Toso Co., Ltd. TSK-GEL G4000H _XL

+ Made by Toso Co., Ltd. TSK-GEL G3000H _XL

+ TSK-GEL G2000H _{XL made by} Toso Co., Ltd.

Detector ; RI (differential refractometer)

Data processing ; MultiStation GPC-8020modelII

Measuring conditions ; Column temperature 40 캜

menstruum Tetrahydrofuran

Flow rate 1.0 ml / min

Standard Using monodisperse polystyrene (A-500, F-20, F-80, F-288, A-2500, F-10, F-40, F-128 and F-380 manufactured by Tosoh Corporation) And a calibration curve was created.

sample ; A tetrahydrofuran solution of 0.5% by mass in terms of resin solid content was filtered with a microfilter (100 μl)

Collect 10.0 g of the sample in a 100 ml Erlenmeyer flask with an upper dish scale.

Add 30 ml of a mixed solvent (toluene / methanol = 7 / 3wt) to a 100 ml measuring cylinder and dissolve.

Add 2 to 4 drops of phenolphthalein indicator.

Titrate with 0.1 mol of alcoholic KOH, and titrate until discoloration lasts for 30 seconds.

Acid value (mgKOH / g) = (V x F x 5.61) / S

V: 0.1 mol / L Alcoholic KOH usage (ml)

F: Tonicity of 0.1 mol / L alcoholic KOH

S: Amount of sample (g)

<Non-volatile matter>

The mass of the metal chalet is weighed with the upper dish scale.

Collect 1.00 g of the sample in the chalet with the upper dish scale.

5 ml of a mixed solvent (toluene / methanol = 7 / 3wt) is added to dissolve.

And dried in a hot air circulating dryer adjusted to 107.5 DEG C for 60 minutes.

After drying, put the chalet into a desiccator, allow it to cool to room temperature, and weigh it with an upper dish scale.

Nonvolatile matter (%) = (B-C) / (A-C) 100

A: metal challe + sample mass before drying (g)

B: Metal chalet + mass of sample after drying (g)

C: Mass of metal chalet (g)

Application example 1

The composition was prepared in accordance with Table 1, the filler was added, the mixture was poured into a bead mill, and a hardener was added to prepare a composition for a paint. The viscosity was adjusted to 20 seconds (25 ° C) in an Iwata cup using xylene / n-butanol / butyl cellosolve = 75/15/10 (mass ratio). The substrate was baked at 150 占 폚 for 20 minutes after coating with spray using less bonder-raising treated steel plate # 144. (Curing 25 占 폚, 50% RH 占 1 day) The coated metal sheet obtained as described above was measured for gloss, Ericsson, duopont impact, pencil hardness, and crosscut test.

Application example 2

A coating material was prepared in the same manner as in Application Example 1 except that the composition ratio (mixing ratio) shown in Table 1 was used to evaluate the coating.

Application Example 3

A base was prepared according to Table 1, a filler was added, and the mixture was coated with a bead mill. Then, a hardener was added to prepare a coating composition. The viscosity was adjusted to 100 seconds (25 DEG C) in a Ford cup using xylene / n-butanol / butyl cellosolve = 75/15/10 (mass ratio). The substrate was baked at 250 캜 for 40 seconds after coating with a bar coater using less bonder-raising treated steel plate # 144. (Curing 25 占 폚 占 50% RH 占 1 day) The obtained coated metal sheets were subjected to gloss, Ericsson, duopont impact, pencil hardness, and crosscut test.

Comparative Application Examples 1, 2

Comparative Application Example 3

A paint was prepared in the same manner as in Application Example 3, except that the composition ratio (mixing ratio) shown in Table 1 was used to evaluate the paint.

Each evaluation judgment item and its evaluation judgment method are as follows.

(1) Luster: The reflectance was measured at a mirror surface of 60 degrees.

(2) Erickson test: The extrusion length (mm) until extrusion by extrusion with an Erickson tester was measured.

(3) DuPont Impact Value: Using a DuPont impact tester, the weight was set at 1.0 kg, and the weight was dropped from the predetermined height onto the coating film with a 1/2 inch notch so that the maximum height (JIS K-5460).

(4) Hardness (pencil hardness): The drawing of the steel sheet was measured according to JIS K-5400 using a high-grade pencil specified in JIS S-6006.

(5) Crosscut test: The steel sheet was measured according to the crosscut test specified in JIS K 5600-5-6.

The raw materials used in the application examples are as follows.

※ 1 Dilution thinner: xylene / n-butanol / butyl cellosolve = 75/15/10 (mass ratio)

Acridic A-405: Acrylic resin nonvolatile content 50% Manufactured by DIC Co., Ltd.

M-6201-40-IM: denatured polyester resin non-volatile content 40% manufactured by DIC Co.

CR-95: Titanium oxide

Claims

(1) a step of polycondensation reaction of an amino compound and an aldehyde in a solvent to obtain a reaction mixture containing an amino resin,
(2) A process for producing a low-free formaldehyde amino resin, which comprises heating the reaction mixture in the above step to 80 to 150 ° C to reflux or deprotect the organic phase.

The method according to claim 1,
Wherein the solvent used in the step (1) comprises an alcohol.

The method of claim 3,
Wherein the alcohol is an alcohol having 1 to 8 carbon atoms.

The method according to any one of claims 1 to 3,
Wherein the solvent used in the step (1) is removed after the step (1), and then the solution is provided as the reaction mixture in the step (2).

The method according to any one of claims 1 to 4,
A process for producing a low-boiling formaldehyde amino resin by mixing a solvent having a boiling point of 80 DEG C or higher in the step (2) and then heating.

The method of claim 5,
Wherein the solvent having a boiling point of 80 DEG C or higher is xylene.

The method according to any one of claims 1 to 6,
Wherein the amino compound is melamine, urea, or benzoguanamine, or a low-free formaldehyde amino resin.

The method according to any one of claims 1 to 7,
Wherein said aldehyde is formaldehyde. &Lt; RTI ID = 0.0 > 11. < / RTI >

A low-free formaldehyde amino resin obtained by the production method according to any one of claims 1 to 8.

The method of claim 9,
A low free formaldehyde amino resin having a content of free formaldehyde in the resin of less than 1% by mass.