KR20030015071A - Process for Preparing Phenolic Resin Nanocomposite comprising Exfoliated Layered-Silicate Using Resol-type Phenolic Resin - Google Patents

Abstract

PURPOSE: Provided is a method for producing a phenol resin-layered silicate nanocomposite by using a resol type phenol resin and the phenol resin-layered silicate nanocomposite therefrom. CONSTITUTION: The method for producing a phenol resin-layered silicate nanocomposite by using a resol type phenol resin comprises the steps of adding water to a water-soluble resol type phenol resin solution to precipitate the resol type phenol resin, followed by drying the precipitation to obtain solid phenol resin; separately, absorbing a layered silicate with an absorbing compound for modification; and kneading the solid phenol resin with the modified layered silicate, followed by thermal treatment to obtain a phenol resin-layered silicate nanocomposite.

Description

Process for Preparing Phenolic Resin Nanocomposite comprising Exfoliated Layered-Silicate Using Resol-type Phenolic Resin

The present invention relates to a method for producing a phenol resin-layered silicate nanocomposite using a resol type phenol resin. More specifically, the present invention is to prepare a peelable phenol resin-layered silicate nanocomposite by kneading a solid resol type phenolic resin obtained by adding excess water to a water-soluble resol type phenolic resin solution and modifying the layered silicate and heat treatment. A method and a phenolic resin-layered silicate nanocomposite prepared therefrom.

Unlike conventional microcomposites, polymer-layered silicate nanocomposites using nano-sized layered silicates exhibit high mechanical properties, thermal stability, self-extinguishing, dimensional stability, and gas permeability even with the addition of small amounts of silicates. This is a very good phenomenon because the structure of the silicate is plate-shaped, and the aspect ratio is large and the area that can interact with the polymer is large. Because of its applicability, the nanocomposites have been actively studied in the United States, Europe, Japan, and the like, and as a good example, Toyota, Japan, used nylon-layered silicate nanocomposites to cover timing belts of automobiles. -belt cover) was the first commercialized product.

However, since layered silicates are hydrophilic and do not mix well with conventional hydrophobic polymers, it is difficult to expect intercalation of the polymers. Therefore, it is not so simple to manufacture polymer-layered silicates. Therefore, in general, alkylammonium or the like is used to convert the layered silicate to hydrophobic, and then insert the polymer between the layers to prepare a nanocomposite. For example, a gas phase monomer or a monomer dissolved in a solvent is organicized. An in-situ method of inserting into silicate and then polymerizing to obtain a nanocomposite was developed by Usuki et al. (A. Usuki et al., J. Mater. Res. , 8 , 1174 (1993)). . Ruiz et al. Also developed a solution insertion method in which a polymer is dissolved in a solvent without the use of monomers, and then inserted into a layered silicate layer (see E. Ruiz-Hitzky and P. Aranda, Adv. Mater ., 2 , 545 (1990)). However, in addition to the disadvantage that the method is not applicable to the polymer processing method widely used in the current industrial field, the former has the advantage that the monomer is easily inserted between the first layer, but there is a problem that requires a post-polymerization process, In the latter case, there is a disadvantage in that the selection of a solvent capable of dissolving the polymer is difficult.

Thus, the Giannelis group of Cornell University developed a method for preparing polymer-layered silicate nanocomposites by using a melt insertion method in which a polymer is directly inserted between layers of silicates in a molten state (see RA Vaia). et al., Chem. Mater. , 5 , 1694 (1993). The melt insertion method is well suited to the processing methods of polymers currently used, which is advantageous for mass production, and does not require the use of a solution, which is advantageous in terms of environment. Recently, methods for synthesizing polymer-layered silicates by direct synthesis of silicates in the presence of polymers have also been developed (KA Carrado, P. Thiyagarajan and DL Elder, Clays Clay Miner ., 44 , 506 (1996)).

By the above methods, layered silicate nanocomposites were prepared for various polymer materials, examples of which are as follows: Nylon (A. Usuki et al., J. Mater. Res. , 8 , 1174 (1993) Polycaprolactone (PB Messersmith et al., Chem. Mater ., 5 , 1064 (1993)), polymethylmethacrylate (L. Biasci et al., Polymer , 35 , 3296 (1994) ), Polystyrene (RA Vaia et al., Chem. Mater ., 5 , 1694 (1993)), polyimide (T. Lan et al., Chem. Mater ., 7 , 573 (1994)) , Polypropylene (M. Kawasumi et al., Macromolecules , 30 , 6333 (1997)), polyethylene (HG Jeon et al., Polym. Bull ., 41 , 107 (1998)), epoxy (see: T. Lan et al., Chem. Mater. , 6 , 2216 (1994)).

On the other hand, phenolic resins are widely used in various fields such as thermostable materials, molding compounds, castings, wood industry, coatings, composites, etc. because of excellent ablative properties, heat resistance, dimensional stability and solvent stability. However, unlike the polymers listed above, it is very difficult to produce nanocomposites using layered silicates, which is very difficult to insert between layers of layered silicates due to the three-dimensional structure of the oligomers of the phenolic resin itself. Because it is difficult. In order to overcome this, Usuki et al. Disclose a method for preparing phenol resin-layered silicate nanocomposites by synthesizing phenolic resins in the presence of layered silicates in US Pat. No. 4,889,885, and Lee et al. A method for preparing a phenol resin nanocomposite using a melt insertion method using a silicate modified with a noblock resin and an alkyl ammonium is disclosed ( JD Lee et al., Polym. Prepr. (Am. Chem. Soc., Div.). Polym. Chem.) , 38 , 688 (1997). In addition, Choi Hoon et al. Prepared a layered silicate modified with a linear noblock resin and various types of alkylammonium using melt-insertion method, and published the morphology and curing behavior at that time, layered silicate prepared according to the type of alkylammonium -Phenol resin nanocomposite mechanical properties have been reported to vary greatly (MH Choi et al., Chem. Mater ., 12 , 2977 (2000); Choi Min-ho, Ph.D. thesis, Korea Advanced Institute of Science and Technology (2001)).

However, these techniques are a method of converting hydrophilic layered silicates into hydrophobic groups using alkylammonium, and then inserting linear noblock resins by melt-insertion method, in which each layer constituting the layered silicates is completely separated. Compared with, it implies a fundamental limitation in the physical properties of nanocomposites. Therefore, the necessity of developing new phenol resin-layered silicate nanocomposites is constantly emerging.

Therefore, the present inventors have overcome the shortcomings of the conventional techniques, and as a result of diligently trying to establish a technique capable of producing a polymer material that can obtain excellent physical properties using nano-sized layered silicate, the resol type phenolic resin adsorption compound When kneading with the layered silicate modified with the present invention, it was confirmed that each layer of the layered silicate can be completely separated, and came to complete the present invention.

After all, the main object of the present invention is to provide a method for producing a peelable phenol resin-layered silicate nanocomposite using a resol type phenol resin.

Another object of the present invention is to provide a peelable phenolic resin-layered silicate nanocomposite prepared from the electric method.

1 is an X-ray diffraction analysis of the resol-type phenolic resin-monnorylonitrile nanocomposite of the present invention.

In the method for producing a phenol resin-layered silicate nanocomposite using the resol type phenolic resin of the present invention, an excessive amount of water is added to a water-soluble resol type phenolic resin solution to precipitate the resol type phenolic resin, and then the precipitate is dried to obtain a solid phenolic resin. Obtaining process; Apart from this, the step of modifying the layered silicate into an adsorbent compound; And mixing the solid phenolic resin with the modified layered silicate, followed by heat treatment to obtain a peelable phenolic resin-layered silicate nanocomposite.

Hereinafter, a method of preparing a phenol resin-layered silicate nanocomposite using the resol type phenol resin of the present invention will be described in more detail by process.

First step : obtaining a solid phenolic resin

Excess water is added to the aqueous solution of a sol-type phenolic resin to precipitate the sol-type phenolic resin, and then the precipitate is dried to obtain a solid phenolic resin: a phenol resin and a nobloc type and basic compound in which phenol and formaldehyde are synthesized under acidic conditions. As the phenol resin used in the present invention is divided into resol type synthesized under the conditions, a monomer is substituted with 1 to 3 methylol (-CH ₂ OH) groups in the phenol ring. One to thirty monomers are linked by a dimethyl ether group or a methyl group, and those having a weight average molecular weight of 4,000 or less are used. This is because when the weight average molecular weight of the phenol resin exceeds 4,000, the viscosity of the phenol resin is too high, resulting in a problem of poor dispersion when adding the layered silicate in a later step.

Second Step : Degeneration of Layered Silicate

Apart from the above process, the layered silicate is modified with an adsorbent compound: wherein the layered silicate is composed of montmorillonite, hectorite, saponite and fluorohectorite As the at least one material selected from, a layer having a thickness of 7 to 12 GPa and an aspect ratio of 10 to 1000 are used. In addition, the adsorption compound is methylamine, propylamine, butylamine, octylamine, decylamine, dodecylamine, N-methyloctadecylamine (N -methyloctadecylamine), 1,6-hexamethylenediamine, 1,12-dodecanediamine, 1,12-dodecanediamine, hexamethylenetetramine, 6-aminohexanoic acid (6 -aminohexanoic acid) and a halogen acid salt of at least one compound selected from the group consisting of 12-aminododecanoic acid; Tetramethylammonium chloride, octadecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, dioctadecyldimethylammonium bromide, dimethylbenzyloctamide bromide bromide bromide ), Bis (2-hydroxyethyl) methyloctadecylammonium chloride (bis (2-hydroxyethyl) methyloctadecylammonium chloride) and hexadecylpyridium bromide, betaalanine (β-alanine), 6-aminocap One or more compounds selected from the group consisting of 6-aminocaproic acid, 12-aminododecainoic acid are used. On the other hand, the amount of the adsorbent compound adsorbed on the layered silicate is preferably 5 to 50wt% of the total amount of the modified layered silicate.

Step 3 : Preparation of Peelable Phenolic Resin-Layered Silicate Nanocomposites

The electrically solid phenolic resin and the modified layered silicate are kneaded and then subjected to heat treatment to prepare a peelable phenolic resin-layered silicate nanocomposite, wherein the amount of the modified layered silicate mixed with the solid phenolic resin is based on the total weight of the nanocomposite. 0.1 to 70 wt%, preferably 1 to 10 wt% is used. If the amount of silicate exceeds 90wt%, the hardening reaction does not occur even after the heat treatment, thereby deteriorating the physical properties of the composite. On the other hand, heat treatment of the modified layered silicate and phenol resin is carried out at 65 ℃ to 220 ℃, for 1 minute to 5 hours. The glass transition temperature of the resol type phenolic resin is about 65 ° C., and heat treatment at a temperature higher than this gives a nanocomposite of a desired physical property. When the heat treatment temperature exceeds 220 ° C., the thermal decomposition of the phenolic resin starts. Not desirable

As the method of heat treatment usable in the present invention, any method capable of maintaining a constant temperature of the resin and silicate mixture can be used. Heat treatment can be performed under vacuum as well as atmospheric pressure, and an apparatus such as an injection machine or a brabender is used. Doing heat treatment without departing from the spirit of the present invention.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are only for illustrating the present invention in more detail, and it will be apparent to those skilled in the art that the scope of the present invention is not limited to these examples according to the gist of the present invention.

Example 1 Preparation of Resol-type Phenol Resin-Monmorillonite Nanocomposite

First, an aqueous water-soluble resol type phenol resin (number average molecular weight 1,026, weight average molecular weight 2,473) containing 85% solids was added to precipitate solids by adding excess water (0.5 times), and then dried in a freeze dryer for about a week. The resultant was dried in a vacuum oven at 80 ° C. for at least 3 days to obtain a solid phenolic resin.

Next, apart from the preparation of the phenol resin, 5 g of montmorillonite (Kunipia-F; Kunimine Co .; CEC = 119 meq / 100 g) was suspended in 400 ml of tertiary distilled water and stirred for at least one day to obtain a montmorillonite dispersion. Then, 12 mmol of 6-aminocaproic acid and 1.2 ml of hydrochloric acid were added to 100 ml of tertiary distillation, and vigorously stirred at 85 ° C. for 1 hour to the montmorillonite dispersion. The precipitate precipitated in the reactor was washed three times with distilled water at the same temperature as the reaction temperature and filtered, and then filtered through a silver mirror reaction to confirm that the unreacted substance was completely washed. The reaction was dried in a lyophilizer for two days, and then dried again in a vacuum oven at a temperature of 100 ° C. or lower for 3 days to obtain modified montmorillonite (adsorption ratio of 6-aminocaproic acid: 15 wt%).

Finally, after mechanically kneading the obtained solid phenolic resin and the modified layered silicate (1, 2, 3, 4 and 5wt% based on the total weight of the resol type phenolic resin-montmorillonite nanocomposite), at 110 ° C Heat treatment for 60 minutes to obtain a phenol resin-montmorillonite nanocomposite.

For the resol-type phenolic resin-silicate nanocomposites prepared above, tensile specimens were prepared according to the method of ASTM638-94, and mechanical properties such as tensile strength were measured, and then summarized in Table 1 below.

Layered Silicate Content (wt%) Tensile Strength (MPa) Tensile Modulus (GPa) Elongation at Break (%) Toughness (MPa) 0 38.09 1.88 1.64 32.89 One 46.13 2.75 2.54 66.73 2 56.50 2.86 2.86 84.15 3 58.33 2.92 3.02 98.03 4 50.17 2.92 2.37 69.69 5 45.80 3.02 2.22 56.21

As shown in Table 1, the phenol resin-montmorillonite nanocomposite of the present invention, despite the montmorillonite content of less than 5wt%, it can be seen that all physical properties such as tensile modulus, tensile strength, elongation at break, stiffness significantly increased. In view of the tendency to decrease all physical properties other than the tensile modulus when using a conventional filler, the effect can be said to be a unique effect of the nanocomposite of the present invention, because the aspect ratio of the nanocomposite of the present invention is very large Judging.

Meanwhile, the nanocomposite of the present invention was subjected to X-ray line analysis to investigate the dispersion state of montmorillonite in the phenol resin. FIG. 1 shows the results of X-ray diffraction analysis of phenol resin-montmorillonite nanocomposites containing 2, 3 and 5 wt% of modified montnorillonite (Rigaku X-ray generator; CuKα radiation, λ = 0.15406 nm, 2θ = 1.2-10 °, scanning speed = 2 ° / min.), A6M shows the diffraction curve of pure montmorillonite. As shown in Figure 1, the (001) peak seen in pure montmorillonite completely disappeared in the resol-type phenol resin-montmorillonite nanocomposite, from which it can be seen that the montmorillonite layers completely peeled and dispersed in the composite.

As described and demonstrated in detail above, in the present invention, the solid resol type phenol resin obtained by adding excess water to the water-soluble resol type phenol resin solution is kneaded with a modified layered silicate and subjected to heat treatment to release the phenolic resin-layered phase. A method for producing silicate nanocomposites and phenolic resin-layered silicate nanocomposites prepared therefrom. According to the present invention, the layered silicate reacts with the hydroxyl group of the phenolic resin and the layered silicate is completely peeled off and dispersed into the phenolic resin. Thus, the peelable phenolic resin-layered layer exhibits significantly improved physical properties while containing a small amount of silicate. Silicate nanocomposites can be prepared.

As described above in detail the specific parts of the present invention, for those skilled in the art, these specific descriptions are only preferred embodiments, which are not intended to limit the scope of the present invention. Will be obvious. Thus, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (8)

Adding an excess amount of water to a water-soluble resol type phenol resin solution to precipitate the resol type phenol resin, and then drying the precipitate to obtain a solid phenol resin; Apart from this, the step of adsorbing the layered silicate with an adsorbing compound to denature it; A method for producing a peelable phenolic resin-layered silicate nanocomposite comprising the step of kneading an electric solid phenolic resin and a modified layered silicate, followed by heat treatment to obtain a peelable phenolic resin-layered silicate nanocomposite. The method of claim 1, Resol type phenol resin is characterized in that the weight average molecular weight of less than 4,000 Method for producing a peelable phenol resin-layered silicate nanocomposite. The method of claim 1, Layered silicates are one or more materials selected from the group consisting of montmorillonite, hectorite, saponite and fluorohectorite, with a layer thickness of 7 to 12 microns and an aspect ratio. Characterized in that is 10 to 1000 Method for producing peelable phenolic resin-layered silicate nanocomposite. The method of claim 1, Adsorption compounds are methylamine, propylamine, butylamine, octylamine, octylamine, decylamine, dodecylamine, N-methyloctadecylamine ), 1,6-hexamethylenediamine, 1,12-dodecanediamine, 1,12-dodecanediamine, hexamethylenetetramine, 6-aminohexanoic acid acid) and a halogen acid salt of at least one compound selected from the group consisting of 12-aminododecanoic acid; Tetramethylammonium chloride, octadecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, dioctadecyldimethylammonium bromide, dimethylbenzyloctamide bromide bromide bromide ), Bis (2-hydroxyethyl) methyloctadecylammonium chloride (bis (2-hydroxyethyl) methyloctadecylammonium chloride) and hexadecylpyridium bromide, betaalanine (β-alanine), 6-aminocap It is characterized in that the at least one compound selected from the group consisting of (6-aminocaproic acid), 12-aminododecainoic acid (12-aminododecainoic acid) Resol type phenolic resin-layered silicate nanocomposite manufacturing method. The method of claim 1, The amount of the adsorbent compound adsorbed on the layered silicate is 5 to 50wt% of the total amount of the modified layered silicate. Method for producing a peelable phenol resin-layered silicate nanocomposite. The method of claim 1, The amount of the modified layered silicate mixed with the solid phenolic resin is 0.1 to 70wt% based on the total weight of the nanocomposite Method for producing peelable phenolic resin-layered silicate nanocomposite. The method of claim 1, Heat treatment of the modified layered silicate and the phenol resin is carried out at 65 ℃ to 220 ℃, for 1 minute to 5 hours Method for producing peelable phenolic resin-layered silicate nanocomposite. Resol type phenolic resin-layered silicate nanocomposite prepared by the method of claim 1.