JPH10266075A - Curable phenolic resin composition for felt and felt molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a curable phenolic resin composition only, slight in the generation of the smell of ammonia, etc., excellent in workability, and useful for felt substrate binders suitable for producing felt products having sufficient strengths. SOLUTION: This curable phenolic resin composition for binding fibrous felt substrates comprises 100 pts.wt. of a phenolic resin, 2-40 pts.wt. of boric acid and 2-25 wt.% of hexamethylenetetramine. The phenolic resin may preliminarily be treated with the boric acid to produce the boric acid-modified phenolic resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a curable phenolic resin composition which can be advantageously used for producing a felt molded article,
The present invention also relates to a felt molded product obtained by binding a fibrous felt base material using the curable phenol resin composition.

[0002]

2. Description of the Related Art Curable phenolic resins are excellent in various points such as heat resistance, chemical resistance, adhesiveness, and economical efficiency. Widely used as a binder for fixing. When using this curable phenolic resin for binding a felt molded product, a fibrous felt base material was mixed with a phenolic resin as a curable component and hexamethylenetetramine as a curing agent, and then the mixture was molded. Thereafter, a method of heating and curing to obtain a felt molded product is generally used. This hexamethylenetetramine is useful as a curing agent for curing phenolic resins in consideration of its high curing ability and excellent versatility, but it generates ammonia during heat curing and deteriorates the manufacturing work environment. There is a problem that the obtained felt molded product is liable to cause ammonia odor to remain easily. It is necessary to avoid as much as possible the deterioration of the working environment due to such ammonia and the ammonia smell remaining on the felt molded product. However, if the addition amount of hexamethylenetetramine is reduced for the purpose of reducing the amount of generated ammonia, the curing ability is reduced, so that the time required for curing (that is, the gel time) becomes longer, There is a problem that the strength of the felt molded product is easily reduced.

[0003]

The object of the present invention is to provide a felt-molded article which, when used in the production of a felt-molded article, produces less odor such as ammonia, has excellent workability, and has sufficient strength. It is an object of the present invention to provide a curable phenol resin composition that can be used.

[0004]

According to the present invention, there is provided a curable phenolic resin composition for felt comprising 100 parts by weight of a phenolic resin, 2 to 40 parts by weight of boric acid, and 2 to 25 parts by weight of hexamethylenetetramine. It is in. In the present invention, the fibrous felt base material may be a phenol resin 1
There is also a felt molded article characterized by being bound by a heat-cured product of a composition of 00 parts by weight, 2 to 40 parts by weight of boric acid, and 2 to 25 parts by weight of hexamethylenetetramine. The present invention further provides a boric acid-modified phenolic resin 102.
To 140 parts by weight (100 parts by weight of phenol resin component and 2 parts by weight)
Curable phenolic resin composition for felt, characterized in that the curable phenolic resin composition comprises 2 to 25 parts by weight of hexamethylenetetramine). Further, in the present invention, the fibrous felt base material may contain 102 to 140 parts by weight of a boric acid-modified phenol resin (consisting of 100 parts by weight of a phenol resin component and 2 to 40 parts by weight of a boric acid component) and 2 to 25 parts by weight of hexamethylenetetramine. There is also a felt molded product characterized by being bound by a heat-cured product of the composition of (1).

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The curable phenolic resin composition for felt of the present invention and a felt molded product produced using the phenolic resin composition will be described in detail below. The phenolic resin of the curable composition of the present invention can be arbitrarily selected and used from various phenolic resins used in conventional felt binders. Examples of such phenolic resins include phenol (or phenol derivatives such as cresol, xylenol, resorcin, bisphenol A) and formaldehyde (formaldehyde or formaldehyde such as paraformaldehyde, formalin, trioxane, etc.). And a novolak-type phenolic resin obtained by reacting with an acid catalyst (oxalic acid, sulfuric acid, hydrochloric acid, paratoluenesulfonic acid, etc.), and a novolak-type phenolic resin and a resol-type phenolic resin. And the like.

The boric acid used together with the phenolic resin may be preliminarily reacted with the phenolic resin to obtain a boric acid-modified phenolic resin, which may be mixed with hexamethylenetetramine, or may be simply mixed with phenolic resin, hexamethylenetetramine and boric acid. May be used as a mixture. The boric acid is used in an amount of 2 to 40 parts by weight (preferably 5 to 35 parts by weight, more preferably 10 to 30 parts by weight) based on 100 parts by weight of the phenol resin. If the amount of boric acid is
If the amount is less than 2 parts by weight with respect to 100 parts by weight of the phenolic resin, the generation of odors such as ammonia during curing of the phenolic resin with hexamethylenetetramine cannot be sufficiently suppressed. None of them is preferable because the physical properties of the product are deteriorated.

[0007] The amount of hexamethylenetetramine used is not particularly limited as long as it is an amount sufficient to cure the phenolic resin to be cured.
It is used in an amount of 2 to 25 parts by weight based on 00 parts by weight.
If the amount of hexamethylenetetramine is too small, sufficient curing of the phenolic resin cannot be achieved, while if the amount of hexamethylenetetramine is too large, the amount of odors such as ammonia gas generated during curing becomes too large. However, the effect of adding boric acid cannot be sufficiently exhibited.

In preparing the curable phenolic resin composition of the present invention, a method of simply mixing a predetermined amount of phenolic resin, boric acid, and hexamethylenetetramine can be used. However, in order to efficiently modify the phenolic resin with boric acid, it is desirable to previously react the phenolic resin with boric acid to obtain a boric acid-modified phenolic resin and mix it with hexamethylenetetramine.

A more detailed operation of the method for once preparing the boric acid-modified phenol resin is as follows. 2 to 40 parts by weight of boric acid are mixed with 100 parts by weight of a phenol resin obtained by reacting phenol and aldehyde in the presence of an acid catalyst, and the mixture is melted by heating to a temperature of 130 to 200 ° C. Thus, a boric acid-modified phenol resin is obtained. Next, the boric acid-modified phenol resin is uniformly mixed with 2 to 25 parts by weight of hexamethylenetetramine with respect to 100 parts by weight of the phenolic resin component in the modified product, and the resulting mass is pulverized. Since the phenol resin composition obtained by such a method is in a powder form, it is difficult to block, and becomes a curable phenol resin composition suitable for practical use.

Next, an operation for producing a felt molded article using the curable phenol resin composition of the present invention will be described. The felt base material is usually an organic fiber or an inorganic fiber or a mixture thereof, and is used by sufficiently opening the fiber when producing a molded product. Then, for example, 10 parts by weight with respect to 100 parts by weight of the opened felt base material.
-60 parts by weight (preferably 20-50 parts by weight) of the curable phenolic resin composition of the present invention is added and mixed well. Then, the mixture is passed through a dryer heated to about 150 ° C. to be pre-cured. Then, the pre-cured product is put into a mold heated to about 200 ° C., and then put under pressure for about 30 seconds by a molding machine so as to have a predetermined cotton density, thereby obtaining a felt molded product. Alternatively, the curable phenolic resin composition of the present invention is sprayed on the opened felt base material, and then supplied to a fleece manufacturing machine. A method of producing a felt by uniformly mixing and dispersing the composition to form a fleece, applying a heated air thereto to melt the resin composition, advance the curing, and bond the fibers of the felt base material to each other. Can also be used.

[0011]

EXAMPLES In the following Examples and Comparative Examples, "parts" means "parts by weight" unless otherwise specified.

Example 1 282 g (3 mol) of phenol, 160 g (2.5 mol) of 47% formalin, and 17 g (0.13 mol) of oxalic acid were placed in a three-necked flask equipped with a condenser and heated at 100 ° C. And reacted under reflux for 3 hours. Next, after allowing the reaction solution to stand, the supernatant is removed. Then, the internal temperature of the reaction solution was increased to 16
Dewater by raising to 0 ° C over 3.5 hours. Then, the dehydrated product was placed under reduced pressure to remove unreacted phenol to obtain a phenol novolak resin. The softening point of the obtained phenol novolak resin was 115 ° C., and the residual amount of unreacted phenol was 3.5%. 10 parts of hexamethylenetetramine and 10 parts of boric acid were mixed with 100 parts of the above phenol novolak resin, mixed well, and then pulverized with a pulverizer to obtain a powdery curable resin composition. Table 1 shows the properties of the obtained curable resin composition.

Example 2 A powdery curable resin composition was obtained in the same manner as in Example 1 except that the amount of boric acid was changed to 20 parts. Table 1 shows the properties of the obtained curable resin composition.

Example 3 A powdery curable resin composition was obtained in the same manner as in Example 1 except that the amount of boric acid was changed to 30 parts. Table 1 shows the properties of the obtained curable resin composition.

Example 4 282 g (3 mol) of phenol, 153 g (2.4 mol) of 47% formalin, and 17 g (0.13 mol) of oxalic acid were placed in a three-necked flask equipped with a condenser and heated at 100 ° C. And reacted under reflux for 3 hours. Next, the condenser is removed, and while removing water generated from the reaction solution, the internal temperature is raised to 160 ° C. over 3.5 hours to perform dehydration. Then, the dehydrated product was placed under reduced pressure to remove unreacted phenol to obtain a phenol novolak resin. 60 g of boric acid (equivalent to 20 parts per 100 parts of phenol resin) was added to the obtained phenol novolak resin,
Heat to 160 ° C. and melt mix. When this molten mixture is cooled, a boric acid-modified phenol novolak resin is obtained. The softening point of this boric acid-modified phenol novolak resin was 113 ° C. The above phenol novolak resin 1
To 100 parts, 10 parts of hexamethylenetetramine was blended, sufficiently mixed, and then pulverized with a pulverizer to obtain a powdery curable resin composition. Table 1 shows the properties of the obtained curable resin composition.

Comparative Example 1 10 parts of hexamethylenetetramine was added to 100 parts of the phenol novolak resin synthesized in Example 1, mixed, and then pulverized with a pulverizer to obtain a powdery curable resin composition. . Table 1 shows the properties of the obtained curable resin composition.

Comparative Example 2 A powdery curable resin composition was obtained in the same manner as in Comparative Example 1 except that the amount of hexamethylenetetramine was changed to 6 parts. Table 1 shows the properties of the obtained curable resin composition.

The gel time of the curable resin composition shown in Table 1 below is a value measured by a hot plate method (150 ° C.).

[0019]

[Table 1] Table 1 ──────────────────────────────────── Properties Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 ゲ ル Gel Conversion time (seconds) 48 47 43 46 47 60 ────────────────────────────────────

From the results shown in Table 1, the curable phenolic resin composition of the present invention shows a gelation time equivalent to that of a conventional general curable phenolic resin composition, while using the hexamethylenetetramine. In Comparative Example 2 in which the amount was reduced, it can be seen that the gelation time was longer.

[Evaluation of production of felt molded article] (1) Production of felt molded article To 70 parts of felt cotton, 30 parts of one of the curable phenolic resins obtained in the above Examples and Comparative Examples were added. After sufficient mixing, pressure molding was performed under the following conditions to obtain a felt molded product. Mold size: 50 mm × 25 mm × 130 mm Mixture weight: 10 g Preheating: 150 ° C. × 3 minutes Molding temperature: 200 ° C. Molding pressure: 100 kg / cm ²

(2) Evaluation of felt molded product 1) Amount of ammonia generated: Felt molded product immediately after production
6 g was put in a 3 liter smell bag (Omi Odoair Service Co., Ltd., O type) and left in an oven at 80 ° C. for 1 hour. Then, the felt molded product was taken out and used with a Kitagawa type detection tube. And the ammonia concentration was measured. 2) Odor concentration: 2.5 g of a felt molded product was placed on a ceramic board, inserted into a ceramic combustion tube heated to 80 ° C., held for 1 hour, and 3 liters of gas coming out from the other end of the combustion tube. And the odor concentration was measured by a method according to the Tokyo three-point comparative odor bag method. 3) Bending strength: Measured using a bending tester (Autograph manufactured by Shimadzu Corporation). Table 2 shows the evaluation results of the above items.

[0023]

[Table 2] Table 2 ──────────────────────────────────── Evaluation items Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 ア ン モ ニ ア Ammonia Generation amount (ppm) 27 15 0 12 80 50 Odor concentration (-) 2.6 2.4 2.2 2.4 2.8 2.7 Flexural strength (kg / cm ² ) 315 302 296 310 326 280 ──────────────────────────────────

From the results shown in Table 2, the felt molded articles produced using the curable phenolic resin composition of the present invention containing boric acid were all replaced with the conventional curable phenolic resin composition containing no boric acid. In comparison, it can be seen that the amount of generated ammonia is small and the odor is small. Also, the bending strength tends to decrease as the amount of boric acid is increased,
This is a sufficient level for practical use. On the other hand, in Comparative Example 2 in which the amount of hexamethylenetetramine used was reduced, the decrease in strength was large.

[0025]

The curable phenolic resin composition for felts of the present invention is characterized by good curability and low generation of gas such as ammonia during curing. That is, the curable phenolic resin composition for felt of the present invention has excellent heat resistance, chemical resistance, and adhesiveness (binding property) almost equivalent to those of the ordinary curable phenolic resin composition for felt. Compared with a commonly used curable phenolic resin composition for felt, generation of gas such as ammonia during the binding operation is small. Therefore, the curable phenolic resin composition for felt of the present invention can be effectively used for producing a felt molded product having excellent physical properties in an improved working environment as compared with the production of a normal felt molded product.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takeshi Takagi 20 Meiji Kasei Co., Ltd., 1988, Ogushi, Ube City, Yamaguchi Prefecture Inside Textile Industry Co., Ltd. (72) Inventor Masanori Irie 2-10-10, Amimishirayama-cho, Kasugai-shi, Aichi 4 Inside Toyawa Textile Industry Co., Ltd. 4. Inside Towa Textile Industry Co., Ltd.

Claims (4)

[Claims] 1. 100 parts by weight of a phenol resin, 2 to boric acid
40 parts by weight, and 2 to 25 of hexamethylenetetramine
A curable phenolic resin composition for felt, comprising parts by weight. 2. The fibrous felt base material is characterized in that the fibrous felt base material is bound by a heat-cured product of a composition of 100 parts by weight of a phenol resin, 2 to 40 parts by weight of boric acid, and 2 to 25 parts by weight of hexamethylenetetramine. Felt molded product. 3. A boric acid-modified phenol resin 102 to 140.
A curable phenolic resin composition for felt, comprising: parts by weight and 2 to 25 parts by weight of hexamethylenetetramine. 4. A felt comprising a fibrous felt base material bound by a heat-cured product of a composition of 102 to 140 parts by weight of boric acid-modified phenol resin and 2 to 25 parts by weight of hexamethylenetetramine. Molded product.