JPS5934733B2 - Method for producing phenolic resin fiber or film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing phenolic resin fibers or films, and more specifically, an improvement in the method for producing fibers or films with excellent mechanical strength using phenolic resins. It is related to.

Conventionally, a thermoplastic resin called novolac, which is obtained by reacting phenol and formaldehyde under acidic conditions, is melt-spun or formed into a film, and then cured with formaldehyde to create a phenolic resin with excellent flame retardant properties. Methods of obtaining fibers or films are known.

Similarly, it is also known to obtain fibers by spinning a resol obtained by reacting phenol and formaldehyde under alkaline conditions, and then heating and curing the resol. Fibers or films obtained from these phenolic resins have a high carbon content and have a three-dimensional crosslinked structure, so they are infusible, nonflammable, and have excellent chemical resistance. For example, phenolic fibers can be used for flame-retardant clothing,
Products are being developed in a wide range of fields, including work clothes, interior wall cloth, jets, papers, various filters, battery separators, felts, curtains, and reinforcing materials for laminated materials. However, the phenolic fibers or films obtained by such conventional methods do not have sufficient mechanical strength, and improvement thereof has been strongly desired.

As a specific means to improve the strength of phenolic fibers, a method has been proposed, such as stretching the fibers in an aqueous solution of methanol and then heat-setting them, but in this case, although the mechanical strength is improved, This was not practical because the elongation decreased and the fibers became brittle. As a result of extensive research based on this viewpoint, the present inventors have found that a phenolic resin that has excellent mechanical strength and elongation when a mixture of novolac and polyamides with resol as an intermediate is used as a raw material for phenolic resin. The present invention was achieved by discovering that fibers or films can be obtained.

That is, the gist of the present invention is to provide a method for producing a phenolic resin fiber or film by melt-spinning or forming a film from a phenolic resin and then curing it with an aldehyde, in which resol is used as the phenolic resin. Novolac obtained by reacting with phenols under neutral or acidic conditions and 0.0% relative to the novolac.
A method for producing a phenolic resin fiber or film characterized by using a mixture with 5 to 40% by weight of polyamides.

Next, to explain the present invention in detail, the resol referred to in the present invention is a condensation product obtained by reacting aldehydes and phenols in the presence of a basic catalyst. Refers to phenolic alcohol that has a methylol group.

As aldehydes used to produce such resols, formaldehyde is usually used, but of course it is not limited to this, and paraformaldehyde, polyoxymethylene, trioxane, furfural, etc. are also used, and these two You may use more than one species in combination.

On the other hand, the phenols applicable to the present invention include compounds that have one or more phenolic hydroxyl groups in one molecule and have two or more vacant positions ortho or para to the phenolic hydroxyl group. If so, either is fine.

In order to generate a three-dimensional crosslinked structure during curing, a compound having three or more vacant ortho and para positions is more preferable. Of course, two or more of the above phenols may be used in combination. More specifically, for example, phenol,
Cresol, chlorophenol, phenylphenol,
Examples include bisphenol-A1 phenolpthalene, resorcinol, methylresorcinol, hydroquinone, and naphthol.

When reacting the above aldehydes and phenols,
Copolymerization can be carried out by using a trifunctional or higher-functional compound having reactivity with aldehydes, for example, a nitrogen-containing compound such as aniline, N-N-dimethylaniline, melamine, cyanuric acid, or a urea compound.

The synthesis of resols needs to be carried out under basic conditions, but there are no particular restrictions on the basic substances used at that time.
Any known basic compound can be used.

For example, basic substances such as those shown below may be mentioned. A
Group bases (1) Periodic table 1 to lithium hydroxide, potassium hydroxide, sodium hydroxide, calcium hydroxide, barium hydroxide, strontium hydroxide, aluminum hydroxide, etc.
Group 3 metal hydroxide.

(2) Tertiary amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, dimethylbenzylamine and triphenylamine.

(3) Tetramethylammonium hydroxide,
Quaternary ammonium hydroxides such as tetraethylammonium hydroxide, tetrabutylammonium hydroxide and trimethylbenzylammonium hydroxide.

(4) High molecular compounds having tertiary or quaternary nitrogen in their side chains, such as strongly basic ion exchange resins.

Group B bases (1) ammonia (2) methylamine, ethylamine, propylamine,
Primary amines such as butylamine and phenylamine.

(3) Secondary amines such as dimethylamine, diethylamine, dipropylamine, dibutylamine and diphenylamine.

(4) Polymer compounds having primary and secondary nitrogen in their side chains, such as weakly basic ion exchange resins.

The basic substances used to synthesize resol are:
As described above, the bases are broadly divided into Group A bases and Group B bases, and in order to better achieve the effects of the present invention, it is preferable to use resols synthesized using Group A bases.

Note that the reaction conditions for synthesizing the resol differ depending on whether a base from group A or group B is used. When using a group A base, the reaction temperature is in the range of 40 to 95°C, preferably 50 to 90°C, and the aldehyde used in the reaction is preferably 1 to 4 mol per 1 mol of phenol.

When the amount of aldehydes is less than 1 mole, the group A base has high activity, so the polymerization reaction is extremely unfavorable. Moreover, if it exceeds 4 moles, unreacted aldehydes will increase, which is not preferable. The amount of Group A base used is 0.5 mol% or more, preferably 0.5 to 20 mol%, based on the charged phenols.
is within the range of

The amount of Group A base is related to the reaction rate of aldehydes, and is 0.
If it is less than 5 mol%, the reaction will not proceed much and the desired resol will not be obtained. Moreover, if it exceeds 20 mol %, the initial heat generation becomes extremely large, making it difficult to control the temperature, which is not industrially advantageous. On the other hand, when using a group B base, the reaction temperature is in the range of 40 to 100°C, preferably 60 to 100°C, and the aldehydes used are phenols 1
It is preferably between 0.5 and 1 mole.

Here, the reason why phenols are used in excess of aldehydes is to add in advance the phenols necessary for reaction under neutral or acidic conditions after resol synthesis. This is because the catalytic activity of the basic substances of group B is slightly lower than that of group A, and the tendency of by-products to produce high molecular weight substances is not affected much by the charging ratio of aldehydes and phenols. After that, the step of adding phenols can be omitted. The amount of Group B base used is 0.5 to 20 mol% based on the charged phenols.
, preferably from 0.5 to 15 mol %, and its amount is related to the reaction rate of aldehydes.

It should be noted that it is not preferable for the resol in the present invention to have a high molecular weight since this will cause gelation.

Therefore, it is desirable that the content of high molecular weight compounds with a molecular weight of 400 or more does not exceed 10%. The method for producing resols has been described in detail above, but the present invention uses the thus obtained resols to react with phenols under neutral or acidic conditions to obtain novolacs, which can be used for fibers or films. It is characterized by:

The resol in the present invention consists of a phenol derivative whose main component is a single compound such as trimethylol phenol, a trimethylol compound having a dinuclear phenol nucleus, or a tetramethylol compound, or any mixture thereof. The novolac of the present invention, which uses the intermediate as an intermediate, has a molecular structure different from that of ordinary linear novolacs, that is, novolacs obtained by reacting phenols and aldehydes in the presence of an acidic catalyst and with an excess of phenols. It is thought that there is a tendency for more branched novolaks to be produced. The production of novolak in the present invention is carried out by, after synthesizing the resol as described above, making the reaction system neutral or acidic and reacting it with phenols.

Specifically, for example, when an insoluble basic polymer is used in the reaction system during resol synthesis, conditions can be adjusted simply by removing a large amount of the polymer, and other In this case, it is sufficient to add an acidic substance in an amount equal to or more than the basic substance used in the resol synthesis.

The acidic substances used in this case include, for example, inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid and perchloric acid, or organic acids such as oxalic acid, malonic acid, acetic acid and maleic acid, but especially those with low activity. Oxalic acid, which has high thermal decomposition properties, is preferred. Depending on the type of base and acid used, the salts produced when neutralizing with acids may be insoluble in the final resin, so a removal step may be necessary. .

In other words, when ammonia or primary to tertiary amine is used as a basic substance during resol synthesis, the neutralized salt will dissolve in the final resin, so there will be no problem during spinning and film formation, and the removal step can be omitted. . However, when other bases are used, the presence of their neutralized salts in the novolac may impair spinnability and reduce the mechanical strength and elongation of the cured fibers and films. Therefore, it is better to remove it by filtering or washing. As the phenols to be reacted with resol, as already described,
Any of the phenols used in synthesizing the resol can be used.

Such phenols may be newly added after the reaction system is made neutral or acidic, or at the same time as the acidic substance is added, or they may be present in excess in advance when synthesizing the resol. Good too. However, the latter case is advantageous when the resol is synthesized under conditions such that an excess of phenols does not interfere with the synthesis of the resol, for example, using a group B base. The molecular weight of the novolak finally obtained is determined by the molar ratio of total phenols and aldehydes used throughout the synthesis of the resol and the novolak. The molar ratio of phenols to aldehydes is selected to be 1.1 to 2.0, preferably 1.2 to 1.6.

If the amount is less than 1.1 times, the reaction between the constituent substances of the resol will be significant, leading to high molecular weight and even gelation, which is undesirable. If the amount exceeds 2.0 times, a large amount of unreacted phenols will react. Not only does it remain in the system, but also the molecular weight of the resulting resin becomes too low, resulting in a resin with a low viscosity that is unsuitable for spinning and film formation, which is undesirable.

The reaction between resol and phenols is usually carried out at 70 to 120°C, preferably 90 to 120°C, for 0.5 to 18 hours, but the reaction is very rapid as the reaction is mainly between the methylol group and the phenols. proceed.

Next, in order to further advance the reaction and drive water out of the system, heating dehydration is usually carried out at a temperature of 100 to 180°C, and when the distillation of water has almost stopped, the temperature is increased to 0 to 50 mmHg.
A nopolac for spinning and film formation can be obtained by expelling unreacted phenols from the system under reduced pressure of 160 to 250°C. The usual aspects of the novolac production method of the present invention have been described above, but when trimethylolphenol is used as the raw material resol, it is said that ideally a branched novolac with the following structural formula can be obtained. .

(American Chemical Society.
DivisiOnOfOrganicOatings
andPIaStic8chemistryll966
(Refer to March 2015, Vol. 26, Black 1, pp. 107-111) Similarly, when a phenol dinuclear tetramethylol compound is used as the raw material resol, for example, the following branched novolak can be obtained. It is thought that it will be possible.

Thus, the novolak obtained under the optimum conditions of the present invention is
It usually has a number average molecular weight of 500 to 2,000 and can be used in melt spinning or film formation without any problem, but it is more preferably 600 to 1,200.

If the molecular weight is less than 500, melt spinning becomes difficult, yarn breakage occurs, or the softening temperature is low, which tends to cause sticking between spun yarns, which is not preferable.

On the other hand, if the molecular weight exceeds 2,000, polymerization is difficult, melt spinnability is rather reduced, and curing reaction is also reduced, which is not preferable. The molecular weight of the novolac used in the present invention can be easily adjusted by, for example, the resol synthesis conditions, the reaction conditions of the resol and the novolac (especially reaction temperature), the vacuum degassing conditions, or the mixing of two or more types of novolac. can be done.

A feature of the present invention is that when producing phenolic resin fibers or films, a mixture of polyamides and a novolak obtained using the above-mentioned resol as an intermediate is used as a phenolic resin raw material. .

To explain the polyamides, examples of the polyamides include 6-nylon, 7-nylon, 9-nylon, 11-nylon, 12-nylon, 6.6-nylon, 6.10-nylon and general formula: 0c ＝《 》
-CONH-C6Hl2岨.

6T-nylon represented by, or general formula; -FOC
{}CONH-CllH22岨.

Examples include 11T-nylon shown in . Further, the polyamide needs to be melt-mixed in an amount of 0.5 to 40% by weight based on the nopolak. This mixture of novolac and polyamides has excellent melt spinnability or film forming properties, and when cured with aldehydes,
Fibers or films with excellent mechanical strength and elongation can be obtained. The mixture of novolak and polyamide obtained in the present invention is melt-spun or formed into a film, and then cured according to a conventionally known curing method.

For example, it is immersed in a mixed aqueous solution of 8 to 25% by weight of an acidic catalyst and 8 to 25% by weight of aldehydes, heated from 20 to 40°C to 80 to 130°C over 1 to 5 hours, and then further heated to that temperature. Curing is carried out by holding for 5 to 50 hours (single-stage curing), or 8 to 25% by weight of an acidic catalyst and 8
immersed in a mixed aqueous solution with ~25% by weight of aldehydes,
80-130℃ over 0.5-4 hours from 20-40℃
After raising the temperature to [2] and holding at that temperature for an additional 0.5 to 4 hours, add 0.5 to 10 wt.% of the basic catalyst and 1 to 40 wt.% of the basic catalyst.
Curing is carried out by a method of curing by treating in a mixed aqueous solution of aldehydes at a temperature of 70 to 120° C. for 0.5 to 3 hours (two-stage curing). As the aldehydes used in the curing reaction, those used in the synthesis of the resol can be used as they are, but formaldehyde is usually preferably used.

Examples of acidic catalysts used in the curing reaction include hydrochloric acid,
Examples include strong acids such as sulfuric acid, phosphoric acid, oxalic acid, hypochlorous acid, and para-toluenesulfonic acid, with hydrochloric acid being particularly preferred. On the other hand, basic catalysts include ammonia, sodium hydroxide, potassium hydroxide, pyridine, and various amines, but ammonia is usually used. In the above curing treatment, by keeping the concentrations of the acidic catalyst, basic catalyst and aldehydes within the above ranges, and further selecting the curing temperature conditions, time conditions and respective concentrations, phenol with excellent mechanical strength and elongation can be produced. A fiber or film based on this method can be obtained.

It is preferable that the phenolic fiber or film cured by the method of the present invention is then treated with ammonia or caustic soda to neutralize and remove the acid adhering to the fiber or film.

Swelling treatment with lower alcohols or acetone is more preferred because acidic catalysts, basic catalysts, aldehydes, unreacted substances, etc. can be easily removed, and fibers or films with high elongation can be obtained. The treatment in this case is usually accomplished by immersing the material in an aqueous solution of 30% by weight or more of lower alcohol or acetone at 30 to 70° C. for several minutes. By esterifying or etherifying the phenolic hydroxyl group of the phenolic fiber or film cured by the above method, a white phenolic resin fiber or film with excellent light fastness can be obtained. .

The reactivity of novolak in the curing reaction decreases as the molecular weight of novolak increases, and within the molecule, the closer the phenol group is to the end, the stronger the reactivity is. Therefore, as estimated from the manufacturing process, the novolak obtained by the present invention has a higher proportion of branched structures than ordinary linear novolak, and has a lower apparent linear shape. Since the portion is short and there are many terminals, it is thought to have excellent curing reactivity. Therefore, by melt-spinning or forming a film from the novolak obtained in the present invention, and then curing it by treating it in a mixed aqueous solution of hydrochloric acid and formaldehyde, for example, a phenolic fiber or film having extremely excellent mechanical strength and elongation can be obtained. is obtained.

Thus, the phenolic fiber or film obtained by the method of the present invention has extremely excellent mechanical strength and does not impair its properties such as infusibility, nonflammability, and chemical resistance, so it is suitable for industrial use. It is expected to be widely used not only as a material but also in the interior design field.

Note that the novolac used in the present invention and the linear novolac synthesized in one step have different infrared absorption spectra, and in particular, when a group A base is used,
Ratio of absorbance between -1 and 1440CTfL-1, B
When using group bases, 760 cm-1 and 820 cm-1
There is a tendency for the ratio of absorbance between and to increase.

In order to obtain a yarn or film with preferable physical properties, Dl4
8O/Dl44O is 0.80 to 1.50 or D76
It is preferable that O/D82O is 0.85 to 1.40. The above absorbance ratio of the infrared absorption spectrum is considered to be one measure indicating the degree of novolak branching. EXAMPLES The present invention will be specifically explained below using examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

Furthermore, in the following examples, "parts" or "parts by weight" are indicated.

[Production of resol]: A-1 to A-3 61 parts of phenol, 158 parts of 37% formalin aqueous solution [
To a mixture consisting of formalin/phenol = 3 (molar ratio)], sodium hydroxide was added in an amount of 5 mol % based on phenol, and a heating reaction was carried out at 70°C for 3 hours to obtain resol A-1.

At this point, the formaldehyde reaction rate was 73%. In addition, resol A-2, A-3
I got it.

The results are summarized in Table 1. Note that the reaction rate of formaldehyde was determined by the hydrochloric acid-hydroxylamine method. [Production of resol]; B-1 to B-3 150 parts of phenol, 80 parts of 37% formalin aqueous solution [
In a mixture consisting of phenol/formalin = 1.4 (mole ratio), 4 mol% of dimethylamine was added to the phenol.
Resol B-1 was obtained by heating and reacting at 70° C. for 3 hours.

At this point, the formaldehyde reaction rate was 47%. In addition, resols B-2 and B-3 were prepared in exactly the same manner as above except that the amount of catalyst or reaction temperature was changed as appropriate.
I got it.

The results are summarized in Table 2. F Example 1 (Experimental black 1-6
) [Manufacture of novolacs]; Novolacs 1 to 3 190 parts of phenol and 6 parts of oxalic acid were added to each of the resols A-1 to A-3 obtained in the above resol production, and the reaction was carried out at 98°C for 2 hours. After that, the mixture was washed and separated three times with 50 parts of 80° C. hot water to remove unreacted substances, oxalic acid, oxalate salts, and the like.

Next, heat dehydration is performed until the temperature inside the system reaches 170°C, and further heat treatment is performed for 1 hour under reduced pressure of a maximum of 10 ml of Hg.
Various novolaks were obtained. [Manufacture of novolacs]; Novolacs 4 to 6 30 parts of a 10% oxalic acid aqueous solution was added to the resols B-1 to B-3 obtained in the above resol production, and the mixture was brought to 98°C under acidic conditions. The reaction was carried out for 2 hours.

The obtained reaction product was heated and dehydrated until the temperature in the system reached 170° C., and further heat-treated for 1 hour under reduced pressure of a maximum of 10 mmHg to obtain various novolaks. Various physical properties of Novolaks 1 to 6 obtained as described above were measured and summarized in Table 3.

The method for measuring each physical property is as follows. Viscosity: Intrinsic viscosity at 30°C in dimethylformamide solution Molecular weight:
Measured using VapOurPressureOsmOmeter.

Amount of residual phenol: Gas chromatography method (D76O/D82O, .Dl48O/Dl44O; K
760 cm-1 and 8 of the infrared absorption spectrum determined by the Br method
20c1n-1 and 1480? -1 and 1440CTI
Ratio of absorbance at L-1 [Production of fibers] Novolaks 1 to 6 obtained as above were melt-mixed with 90 tons of 10f7 of 12-nylon, and heated at 165°C using a spinneret with a diameter of 18 and a hole diameter of 0.20 nφ. Perform melt spinning at 1200
m/7f1i! It was rolled up at a winding speed of 1.

Next, each spun yarn was mixed with 12.5% by weight of hydrochloric acid and 10.0% by weight of hydrochloric acid.
in a mixed aqueous solution consisting of wt% orthophosphoric acid and 14.5 wt% formaldehyde at 39-42°C for 30 minutes, at 54-57°C for 30 minutes, and at 74-77°C for 30 minutes.
Pre-cure by immersing at 98-100°C for 30 minutes, and after washing with water, further treat at 95-97°C for 60 minutes in a mixed aqueous solution consisting of 2.0% by weight ammonia and 20% by weight formaldehyde to complete curing. I forced it. After washing the thus obtained cured yarn with water, it was treated with 3.0% by weight ammonia water.
After treatment at 5° C. for 5 hours, it was washed with water and dried. The physical properties of the obtained cured yarn were measured and are summarized in Table 4.

The method for measuring each physical property is as follows.

Breaking strength: Test yarn with a length of 2crrL was 201B/
The thread is pulled at a speed of 1 minute, and the load applied is measured at the point at which the thread breaks.

Elongation at break: A test is conducted in the same manner, and the elongation of the yarn at the time of breakage is expressed as the elongation percentage relative to the original yarn.

Comparative Example 1 [Manufacture of Novolak] A mixture consisting of 150 parts of phenol, 105 parts of a 37% aqueous formalin solution, and 7.5 parts of a 10% aqueous oxalic acid solution was
The reaction was carried out at 8°C for 4 hours.

Next, it was dehydrated by heating until the temperature in the system reached 170°C, and then heat-treated for 1 hour under reduced pressure of a maximum of 10 mL of Hg to obtain a linear novolac (abbreviation: linear novolac). Various physical properties of this resin were Measurements were made in the same manner as in Example 1, and the results are also listed in Table 3 above.

[Fiber manufacturing]

The linear novolak obtained as above was also melt-spun with 12-nylon added in the same manner as in Example 1.
A hardening process was performed.

The physical properties of the obtained cured yarn were measured in the same manner as in Example 1, and the results are also listed in Table 4 above.

As is clear from Table 4, the cured yarn obtained by mixing 12-nylon with the novolak obtained by the method of the present invention, melt-spinning it, and then curing it, is different from that when conventional linear novolak is used. In comparison, it showed very good strength and elongation.

Claims (1)

[Scope of Claims] 1. A method for producing phenolic resin fibers or films by melt-spinning or forming a film from a phenolic resin and then curing it with an aldehyde, in which resol is used as the phenolic resin under neutral or acidic conditions. 2. A method for producing phenolic resin fibers or films, which comprises using a mixture of novolak obtained by reacting with phenol and polyamide in an amount of 0.5 to 40% by weight based on the novolak. 2. The manufacturing method according to claim 1, wherein the polyamide is 12-nylon.