JP3729469B2 - Method for producing curable resin composition - Google Patents

Description

【００１９】
表１を参照すると、実施例１，２，３によって得られた硬化性樹脂組成物（Ａ），（Ｂ），（Ｃ）は比較的温度が低くても比較例１の硬化性樹脂組成物（Ａ−１）よりも硬化速度が速いことが認められる。
【００２０】
〔実施例４〕
実施例１と同様の反応容器中に、フェノール１モル（９４ｇ）、３７％ホルムアルデヒド水溶液０．８モル（６４．８ｇ）、３５％塩酸０．１ｇを加え、８０℃で２時間反応させた後、常圧で蒸留を行ない、４時間後に液温が１２０℃になったところで５−メチルレゾルシン０．４モル（４９．６ｇ）を加え、１２５℃で３時間反応させ硬化性樹脂組成物（Ｄ）を得た。このものの軟化点は８９℃であった。
上記硬化性樹脂組成物（Ｄ）微粉末１００重量部に対し、ヘキサメチレンテトラミン微粉末を１５重量部を加え、均一に攪拌混合した混合物を、麻繊維６０％、再生繊維２５％、パルプ５％からなる混合繊維に８％になるように添加し絡合機によってシート状に絡合した後、１３０℃、２．５kg／cm² の圧力で４５秒ホットプレスし、厚さ２mm、比重０．７のシート状に成形した。このものは軽量で耐熱性、剛性、強度ともに優れたシート状構造材が得られた。
【００２１】
〔比較例２〕
実施例４においてフェノール１モル（９４ｇ）、３７％ホルムアルデヒド水溶液０．８モル（６４．８ｇ）、３５％塩酸０．１ｇを加え、８０℃で６時間反応させた後、５−メチルレゾルシン０．４モル（４９．６ｇ）を加え、１００℃で反応させたところ、１時間後にゲル化した。
【００２２】
〔実施例５〕
実施例１と同様の反応容器中に、フェノール１モル（９４ｇ）、３７％ホルムアルデヒド水溶液０．２モル（１６．２ｇ）、蓚酸０．２ｇを加え、１００℃で１時間反応させた後、１００mmＨｇの減圧下で蒸留を行ない、２時間後に液温が１１０℃になったところで２，５−ジメチルレゾルシン０．２モル（２８ｇ）と蓚酸０．１ｇを加え、１２０℃で４．５時間反応させ硬化性樹脂組成物（Ｅ）を得た。このものの軟化点は７８℃であった。
上記硬化性樹脂組成物（Ｅ）１００重量部に対し、木粉１５０重量部、綿屑５０重量部、ステアリン酸マグネシウム２重量部、ヘキサメチレンテトラミン２０重量部を均一に混合した後、１５０℃で４０秒間熱圧プレスし厚さ５mm、密度１．５ｇ／cm³ の剛性に優れた成形材料が得られた。
【００２３】
表１により、本発明による硬化性樹脂組成物は従来のノボラック型フェノール−多価フェノール共縮合樹脂組成物に比して、低温で短時間で硬化することがわかる。また多価フェノールでもレゾルシンよりもアルキルレゾルシンの方がより低温短時間で硬化することがわかる。また比較例２により従来の製造方法では反応途中でゲル化することがあることもわかる。
【００２４】
【発明の効果】
本発明においてはフェノールホルムアルデヒド初期縮合物に多価フェノールを共縮合させる際に遊離のホルムアルデヒドが実質的に除去されているから、フェノール−多価フェノールの均一完全な共縮合体が得られ、該共縮合体からなる硬化性樹脂組成物は可使時間が長くかつ低温で速やかに硬化する。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a curable resin composition that can be cured at a low temperature in a short time.
[0002]
[Prior art]
Conventionally, as this kind of curable resin composition, a novolac type phenol-polyhydric phenol cocondensation resin composition has been provided.
The novolac type phenol-polyhydric phenol cocondensation resin composition is produced by a method in which a phenol and formaldehyde are subjected to a condensation reaction using an acid catalyst, and polyhydric phenol is added in the course of the reaction to cause cocondensation. Is done.
[0003]
[Problems to be solved by the invention]
However, according to such a method, the amount of formaldehyde added must be increased by an amount corresponding to the amount of polyhydric phenol. As a result, a large amount of active aldehyde is present in the reaction system, and the reaction can be controlled. There is a problem that only a polyhydric phenol is difficult to react with formaldehyde or gelation occurs during the reaction, making it difficult to obtain a uniform and complete cocondensation reaction.
[0004]
[Means for Solving the Problems]
In the present invention, as means for solving the above conventional problems, 0.05 to 0.9 mol of formaldehyde and / or formaldehyde donor is added in terms of free formaldehyde with respect to 1 mol of phenol, and a catalyst is added. Step 1 in which a phenol-formaldehyde precondensate is produced by heating reaction
Step 2 of distilling the reaction solution to remove excess formaldehyde
Step 3 of adding 0.01 to 0.5 mol of polyphenol to the heated melt of the phenol-formaldehyde initial condensate and causing the reaction to heat
The manufacturing method of the curable resin composition which consists of the above processes 1, 2, and 3 is provided.
Desirably, the reaction in step 1 is carried out at a temperature of 50 to 100 ° C. for 0.5 to 10 hours, and the distillation in step 2 is carried out at a temperature of 120 to 180 ° C. for 0.5 to 5 hours at normal pressure. In the case of reduced pressure of ˜150 mmHg, the reaction is carried out for 0.5 to 5 hours until it reaches 70 to 110 ° C., and the reaction in Step 3 is carried out at a temperature of 80 to 130 ° C. for 0.5 to 5 hours.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below, but the examples in the following description do not limit the present invention.
[Formation of phenol-formaldehyde initial condensate (step 1)]
Examples of the phenols used in the present invention include phenol, alkylphenols such as o-cresol, m-cresol, p-cresol, ethylphenol, iso-propylphenol, xylenol, 3,5-xylenol, butylphenol, and nonylphenol, or o-fluorophenol, m-fluorophenol, p-fluorophenol, o-chlorophenol, m-chlorophenol, p-chlorophenol, o-bromophenol, m-bromophenol, p-bromophenol, o-iodophenol, m-iodophenol, p-iodophenol, o-aminophenol, m-aminophenol, p-aminophenol, o-nitrophenol, m-nitrophenol, p-nitrophenol, 2,4, -dinitrophenol, 2, Monohydric phenol substitutes such as 4,6-trinitrophenol Alternatively, one or a mixture of two or more monohydric phenols such as naphthols is exemplified.
[0006]
In the present invention, if desired for the above phenols, urea, melamine, thiourea, benzoguanamine, toluene, xylene, coumarone, cyclohexanone, cashew oil, tannins, dammer, shellac, rosin or rosin derivative, petroleum resin, methanol, One or more of ethanol, isopropanol, butanol, ethylene glycol, glycerin, furfuryl alcohol, linseed oil, tung oil, castor oil and the like may be added for modification.
[0007]
In the present invention, the above phenols are subjected to a condensation reaction with formaldehyde and / or an aldehyde donor. Examples of the aldehyde donor used in the present invention include paraformaldehyde, trioxane, acetaldehyde, propionaldehyde, polyoxymethylene, chloral, Hexamethylenetetramine, furfural, glyoxal, n-butyraldehyde, caproaldehyde, benzaldehyde, acrolein, tetraoxymethylene, phenylacetaldehyde, o-tolualdehyde, m-tolualdehyde, p-tolualdehyde, salicylaldehyde, etc. A mixture of two or more of these is exemplified.
[0008]
As the catalyst used in the condensation reaction in the present invention, an acid catalyst and / or a divalent metal salt is used. Examples of the acid catalyst include hydrochloric acid, sulfuric acid, orthophosphoric acid, boric acid, oxalic acid, formic acid, acetic acid, butyric acid, benzenesulfonic acid, phenolsulfonic acid, p-toluenesulfonic acid, naphthalene-α-sulfonic acid, naphthalene-β-sulfonic acid, Inorganic or organic acids such as methanesulfonic acid, or organic acid esters such as dimethyl oxalate, acid anhydrides such as maleic anhydride, phthalic anhydride, ammonium chloride, ammonium sulfate, ammonium nitrate, ammonium oxalate, ammonium acetate, Ammonium salts such as ammonium phosphate, ammonium thiocyanate and ammonium imide sulfonate, monochloroacetic acid and its sodium salt, organic halides such as α, α 'dichlorohydrin, hydrochloric acid of amines such as triethanolamine hydrochloride and aniline hydrochloride Salt, salci Urea adducts such as acid urea adduct, urea stearate adduct, urea heptanoate adduct, N-trimethyltaurine, zinc chloride, zinc acetate, calcium chloride, calcium sulfate, magnesium chloride, magnesium sulfate and other divalent metal salts, second chloride There is iron. Two or more acid catalysts may be used in combination.
[0009]
In the condensation reaction of the phenols with formaldehyde and / or aldehyde donor, the formaldehyde and / or aldehyde donor is usually added in an amount of 0.05 to 0.9 mol in terms of free formaldehyde with respect to 1 mol of phenol. The reaction temperature is usually 50 to 100 ° C. and the reaction time is usually 0.5 to 10 hours. And the addition amount of an acid catalyst and / or a bivalent metal salt is added about 0.001-10 weight part with respect to 100 weight part of phenols. The above condensation reaction is solvent-free or water or a mixed solvent of water and a water miscible solvent such as methyl alcohol, ethyl alcohol, iso-propanol, acetone, methyl ethyl ketone, tetrahydrofuran, ethyl acetate, cellosolve acetate, methyl cellosolve, ethyl cellosolve, etc. Done in. Here, free formaldehyde means all formaldehyde having the possibility of reacting with phenol in the reaction of phenols.
In the condensation reaction, a phenol-formaldehyde initial condensate is produced.
[0010]
[Distillation (Process 2)]
In the reaction product in which the phenol-formaldehyde initial condensate is generated, excess formaldehyde is contained in a free state. Therefore, when the reaction product is distilled and a solvent is present, excess formaldehyde is removed from the reaction product together with the solvent.
The distillation is carried out at normal pressure or reduced pressure. In the case of normal pressure, the distillation is usually carried out at a temperature of 120 to 180 ° C. for 0.5 to 5 hours. Until 70-110 ° C. Moreover, you may add azeotropic components, such as xylene, toluene, and benzene, if necessary at the time of the said distillation.
Excess free formaldehyde contained in the reaction product is substantially removed by the distillation.
[0011]
[Reaction with polyhydric phenol (step 3)]
In the present invention, polyphenol is added in the molten state of the phenol-formaldehyde initial condensate.
Examples of the polyhydric phenol include resorcin, alkyl resorcin, catechol, alkyl catechol, hydroquinone, alkyl hydroquinone, pyrogallol, phloroglysin, bisphenol, dihydroxynaphthalene, etc. Among the polyhydric phenols, alkyl resorcin is particularly desirable. There is. The curable resin composition of the present invention using the alkylresorcin is excellent in storage stability and cured in a short time at a low temperature, and the cured product is excellent in water resistance, heat resistance, weather resistance and excellent flexibility.
Examples of the alkyl resorcin include 5-methyl resorcin, 5-ethyl resorcin, 5-propyl resorcin, 5-n-butyl resorcin, 4,5-dimethyl resorcin, 2,5-dimethyl resorcin, 4,5-diethyl resorcin, 2 , 5-diethyl resorcin, 4,5-dipropyl resorcin, 2,5-dipropyl resorcin, 4-methyl-5-ethyl resorcin, 2-methyl-5-methyl resorcin, 2-methyl-5-ethyl resorcin, 2 -Methyl-5-propylresorcin, 2,4,5-trimethylresorcin, 2,4,5-triethylresorcin, etc. Among them, 5-methylresorcin is particularly good at low temperature curability and water, heat and weather resistance It is desirable as a polyhydric phenol used in the present invention because it gives a cured product having excellent flexibility. In addition, mixed alkyl resorcin (shale oil resorcin) obtained by dry distillation of Estonian oil shale is obtained at a lower cost, and gives a curable resin composition that is more excellent in low temperature curability, flame resistance, water resistance, heat resistance, weather resistance, etc. Therefore, it is a particularly desirable polyphenol.
The polyphenol is added in an amount of 0.01 to 0.5 mol per mol of phenol. When the reaction is further continued after the addition of the polyhydric phenol, the polyhydric phenol undergoes a condensation reaction with the active aldehyde present in the phenol-formaldehyde precondensate. In the above reaction, if desired, the same catalyst as that used for the phenol-formaldehyde initial condensate may be used. In this way, in the present invention, a curable resin composition in which polyphenol is further co-condensed with the phenol-formaldehyde initial condensate is obtained. Excess free aldehyde is substantially removed, so that the reaction can be easily suppressed and a uniform reaction can be obtained.
[0012]
[Third substance]
In the present invention, if necessary, a third substance can be added to the curable resin composition. Examples of the third substance include natural rubber and derivatives thereof, SB, AB, ABS, SBR, NBR, CR, EPT, isoprene rubber, isoprene-isobutylene rubber and the like synthetic rubber, vinyl acetate resin, ethylene-vinyl acetate copolymer resin , Acrylic resin, methacrylic resin, vinyl chloride resin, vinylidene chloride resin, polystyrene, polyethylene, polypropylene, chlorinated polyethylene, chlorinated polypropylene, polyester resin, urethane resin, polyamide resin, epoxy resin, butyral resin, polyacrylic acid, polyacrylamide , Synthetic resins such as polyvinyl alcohol, cellulose derivatives such as methyl cellulose, carboxymethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, sodium alginate, starch, starch inducer Body, gelatin, glue, protein such as blood powder, calcium carbonate, talc, carbon black, silica, wood powder, walnut powder, coconut shell powder, wheat flour, filler, pigment, dye, preservative, insecticide, anti-aging agent UV absorbers, antioxidants, antimony trioxide, aluminum hydroxide, bromide and other flameproofing agents, waxes, mold release agents such as silicone resins, water repellents, etc., one or more of these It may be added and modified for blending.
[0013]
【Example】
[Example 1]
In a reaction vessel equipped with a thermometer, a cooler, and a stirrer, 1 mol of phenol (94 g), 37 wt% (hereinafter simply referred to as “%”) formaldehyde aqueous solution 0.5 mol (40.5 g), and oxalic acid 0.5 g After reacting at 75 ° C. for 6 hours, distillation was performed at normal pressure, and after 3 hours, when the liquid temperature reached 115 ° C., 0.2 mol (22 g) of resorcin was added and reacted at 120 ° C. for 4 hours to cure. A resin composition (A) was obtained.
The softening point of this product was 86 ° C.
[0014]
[Comparative Example 1]
In the same reaction vessel as used in Example 1, 1 mol of phenol (94 g), 0.5 mol of 37% formaldehyde aqueous solution (40.5 g) and 0.5 g of oxalic acid were added and reacted at 75 ° C. for 9 hours. Then, 0.2 mol (22 g) of resorcin was added, reacted for 4 hours under reflux, and then dehydrated to obtain a curable resin composition (A-1). The softening point of this product was 85 ° C.
[0015]
[Example 2]
A reaction was carried out under the same conditions as in Example 1 except that resorcin was changed to 0.2 mol (24.8 g) of 5-methylresorcin in Example 1, thereby obtaining a curable resin composition (B). The softening point of this product was 87 ° C.
[0016]
Example 3
A curable resin composition (C) was obtained by carrying out the reaction under the same conditions as in Example 1 except that resorcin was changed to 0.2 mol (29.6 g) of alkylresorcin in Example 1. The softening point of this product was 86 ° C.
[0017]
The curable resin compositions (A), (B), (C), and (A-1) obtained in Examples 1, 2, 3 and Comparative Example 1 were finely powdered, and each 100 parts by weight of hexa Table 1 shows the results of measuring the gelation time at each temperature of a mixture obtained by adding 15 parts by weight of methylenetetramine fine powder, sufficiently stirred and uniformly mixed according to JIS-K6910.
[0018]
[Table 1]

[0019]
Referring to Table 1, the curable resin compositions (A), (B), and (C) obtained in Examples 1, 2, and 3 were curable resin compositions of Comparative Example 1 even when the temperature was relatively low. It is recognized that the curing rate is faster than (A-1).
[0020]
Example 4
In the same reaction vessel as in Example 1, 1 mol of phenol (94 g), 37% formaldehyde aqueous solution 0.8 mol (64.8 g), and 35 g hydrochloric acid 0.1 g were added and reacted at 80 ° C. for 2 hours. Then, distillation was performed at normal pressure, and after 4 hours, when the liquid temperature reached 120 ° C., 0.4 mol (49.6 g) of 5-methylresorcin was added and reacted at 125 ° C. for 3 hours to obtain a curable resin composition (D ) The softening point of this product was 89 ° C.
A mixture obtained by adding 15 parts by weight of hexamethylenetetramine fine powder to 100 parts by weight of the curable resin composition (D) fine powder and uniformly stirring and mixing the mixture is 60% hemp fiber, 25% regenerated fiber, and 5% pulp. After being added to the mixed fiber consisting of 8% and entangled in a sheet form by an entanglement machine, it was hot-pressed at 130 ° C. and a pressure of 2.5 kg / cm ² for 45 seconds, thickness 2 mm, specific gravity 0. 7 into a sheet shape. This was a lightweight sheet-like structural material with excellent heat resistance, rigidity and strength.
[0021]
[Comparative Example 2]
In Example 4, 1 mol of phenol (94 g), 0.8 mol (37. 8 g) of 37% aqueous formaldehyde solution and 0.1 g of 35% hydrochloric acid were added and reacted at 80 ° C. for 6 hours. When 4 mol (49.6 g) was added and reacted at 100 ° C., gelation occurred after 1 hour.
[0022]
Example 5
In a reaction vessel similar to Example 1, 1 mol of phenol (94 g), 37% formaldehyde aqueous solution 0.2 mol (16.2 g) and 0.2 g of oxalic acid were added and reacted at 100 ° C. for 1 hour, and then 100 mmHg 2 hours later, when the liquid temperature reached 110 ° C., 0.2 mol (28 g) of 2,5-dimethylresorcin and 0.1 g of oxalic acid were added and reacted at 120 ° C. for 4.5 hours. A curable resin composition (E) was obtained. The softening point of this product was 78 ° C.
After uniformly mixing 150 parts by weight of wood flour, 50 parts by weight of cotton dust, 2 parts by weight of magnesium stearate and 20 parts by weight of hexamethylenetetramine with respect to 100 parts by weight of the curable resin composition (E), at 150 ° C. A molding material excellent in rigidity having a thickness of 5 mm and a density of 1.5 g / cm ³ was obtained by hot-pressing for 40 seconds.
[0023]
Table 1 shows that the curable resin composition according to the present invention is cured at a low temperature in a short time as compared with the conventional novolac type phenol-polyhydric phenol cocondensation resin composition. In addition, it can be seen that alkylresorcin is cured at a lower temperature and in a shorter time than polyresphenol. It can also be seen from Comparative Example 2 that the conventional production method may cause gelation during the reaction.
[0024]
【The invention's effect】
In the present invention, since the free formaldehyde is substantially removed when the polyhydric phenol is co-condensed with the phenol formaldehyde initial condensate, a uniform and complete co-condensate of phenol-polyhydric phenol is obtained. The curable resin composition composed of the condensate has a long pot life and is rapidly cured at a low temperature.

Claims (3)

Formaldehyde and / or formaldehyde donor is added in an amount of 0.05 to 0.9 mol in terms of free formaldehyde with respect to 1 mol of phenols, and a catalyst is added to cause a heat reaction to form a phenol-formaldehyde initial condensate. Process 1
Step 2 of distilling the reaction solution to remove excess formaldehyde
Step 3 of adding 0.01 to 0.5 mol of polyphenol to the heated melt of the phenol-formaldehyde initial condensate and causing the reaction to heat
A method for producing a curable resin composition comprising the above steps 1, 2, 3 The reaction in Step 1 is carried out at a temperature of 50 to 100 ° C. for 0.5 to 10 hours, and the distillation in Step 2 is carried out at a temperature of 120 to 180 ° C. for 0.5 to 5 hours at normal pressure, and 100 to 150 mmHg. 2. The curable resin composition according to claim 1, wherein the pressure is reduced to 70 to 110 ° C. in 0.5 to 5 hours, and the reaction in Step 3 is performed at a temperature of 80 to 130 ° C. for 0.5 to 5 hours. Manufacturing method The method for producing a curable resin composition according to claim 1 or 2, wherein the catalyst used in step 1 and step 3 is an acid catalyst and / or a divalent metal salt.