JPS5934727B2 - 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.

1 Conventionally, thermoplastic resins obtained by reacting phenol and formaldehyde under acidic conditions, so-called novolak resins, are melt-spun or film-formed, and then hardened with formaldehyde to create phenolic resins with excellent flame retardant properties. Methods of obtaining resin fibers or films are known.

Similarly, a method is also known in which fibers are obtained by spinning a resol obtained by reacting phenol and formaldehyde under alkaline conditions and then simply heating and curing the resulting 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 and nonflammable, and also have excellent chemical resistance. For example, phenolic fibers are being developed in a wide range of fields as disaster prevention clothing, work clothes, interior wall fabrics, jets, papers, various filters, battery separators, felts, curtains, and reinforcing materials for laminated materials. . However, the phenolic resin 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 used novolac with resol as an intermediate as a phenolic resin raw material, and performed curing treatment with aldehydes for a long time in the presence of an acidic catalyst. It was discovered that a phenolic fiber or film having excellent mechanical strength and elongation can be obtained, and the present invention was achieved. That is,
The gist of the present invention is to provide 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 to obtain a neutral resin. Alternatively, using a novolac obtained by reacting with phenols under acidic conditions, and curing with the aldehyde in the presence of an acidic catalyst, the temperature is raised from 20 to 40 °C to 80 to 130 °C over 1 to 5 hours, 5-5 more to that temperature
The present invention relates to a method for producing a phenolic resin fiber or film, characterized in that the method is carried out by holding for 0 hours. 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 used in 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, examples include phenol, cresol, chlorophenol, phenylphenol, 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.

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

(Branch) 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 (support) Primary amines such as methylamine, ethylamine, propylamine, butylamine and phenylamine.

(3) Secondary substances such as dimethylamine, diethylamine, dipropylamine, dibutylamine and diphenylamine
grade amine.

(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 vary 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 0.

It is 5 to 15 mol%, and the 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 because it 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 and reacts them with phenols under neutral or acidic conditions to obtain novolaks, which are then used for fibers or films. It is characterized by this.

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 branched novolaks to be produced in large numbers.

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 final novolak is determined by the molar ratio of total phenols and aldehydes used throughout the resol synthesis and novolak synthesis. The molar ratio of the phenols to the phenols 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 noticeable, 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 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 the resol and the phenols is usually carried out at 70 to 120°C, preferably 90 to 120°C, for 0.5 to 18 hours. Zko:;
For the purpose of extracting X::-, heat dehydration is usually carried out at a temperature of 100°C, and when the water has almost subsided, unreacted ferrals are removed from the system under conditions of 160 to 250°C under 0 to 50 mmHg. By expelling it to the outside, novolak for spinning and film formation can be obtained.

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. o(America)
nChemicalSOciety. DivisiOn
OfO wholesaleRcOatingsandPlas-Tic
(See Chemistryll March 966, 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 novolaks can be obtained. It is thought that it can be obtained.

7-1
---2: Enemy:,':X':! ′! ．． =W:: Lieutenant Governor;
It can be used without any problem in melt spinning or film formation, but more preferably 60
It is 0-1200.

If the molecular weight is less than 500, melt spinning is 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, resol synthesis conditions, reaction conditions (especially reaction temperature) of the resol and novolac, vacuum degassing conditions, or mixing two or more types of novolac. can be done.

After the novolak obtained in the present invention is melt-spun or formed into a film, it is cured by reacting with an aldehyde in the presence of an acidic catalyst.

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,
Sulfuric acid, phosphoric acid, oxalic acid, hypochlorous acid, para-toluenesulfonic acid and the like are mentioned, and hydrochloric acid is particularly preferably used. The above aldehydes and acidic catalysts are usually both used as aqueous solutions, and their concentrations range from 8 to 25%.
% by weight is particularly preferred.

An important feature of the present invention is the temperature control method during the curing reaction.

That is, after melt spinning or film formation, it is first immersed in a curing bath maintained at 20 to 40°C, slowly raised to 80 to 130°C over 1 to 5 hours, and then heated to that temperature for 5 The aim is to continue the heat treatment for a long time of up to 50 hours. It is undesirable to immerse the fiber or film in a curing bath with a temperature exceeding 40° C. from the start of the curing process, or to start raising the temperature rapidly after immersion even at a low temperature, as this may cause the fibers or film to stick or devitrify. Furthermore, 80-1
After raising the temperature to a predetermined temperature of 30° C., it is necessary to complete the curing treatment over a sufficient period of 5 to 50 hours. This long-term curing is an essential step in order to obtain favorable mechanical strength and elongation of the fiber or film. 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, 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. 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 can be used as an industrial material. It is expected that it will be widely used not only in the field of interior design 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, the infrared absorption spectrum is 1480CTf.
L-1 and 1440Cr! The ratio of absorbance with L-1,
When group B bases are used, 760 礪二1 and 820CTr
There is a tendency for the ratio of absorbance to L-1 to become larger.

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" indicate "parts by weight".

Production of resol; A-1 to A-18 61 parts of phenol, 158 parts of 37% formalin aqueous solution [
Sodium hydroxide was added to a mixture of formalin/phenol (mole ratio: 3 to 3) 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
A-18 was obtained from -2.

The results are summarized in Table 1.

In addition, The reaction rate of formaldehyde is Determined using the hydroxylamine method.

Production of resol; B-1 to B-10 150 parts of phenol, 80 parts of 37% formalin aqueous solution [
Dimethylamine was added to a mixture of phenol/formalin = 1.4 (mole ratio) in an amount of 4 mol % based on phenol, and a heating reaction was carried out at 70°C for 3 hours to obtain resol B-1.

At this point, the formaldehyde reaction rate was 47%. In addition, resol B
B-10 was obtained from -2.

The results are summarized in Table 2.

Example 1 [Manufacture of novolak] Manufacture of resols 190 parts of phenol and 6 parts of oxalic acid were added to each of the resols obtained in A-1 to A-18.
After reacting at 8°C for 2 hours, 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 in the system reaches 170°C,
Further, various novolaks were obtained by heat treatment for 1 hour under reduced pressure of a maximum of 10 TIL mHg. Table 3 shows the measurement results of the viscosity, molecular weight, residual phenol content, absorbance ratio of IR spectrum, etc. of these resins. The measurement method for each physical property in Table 3 is as follows.

Viscosity; Intrinsic viscosity at 30°C in dimethylformamide solution Molecular weight; VapOurPressureOsmOme
It was measured using ter.

Amount of residual phenol; gas chromatography method D76O/D82O, . Dl48O/Dl44O; KB
760, 1 and 82 of the infrared absorption spectrum obtained by the r method.
Ratio of absorbance at 0 cm-1, 1480 cm-1 and 1440 cm-1 [Production of fibers] Next, the novolaks 1 to 18 obtained as described above were prepared using a spinneret with a hole diameter of 0.25 mmφ (30 spinnerets), 135
Melt spinning was carried out at ~160°C, and a spun yarn was obtained by winding at a winding speed of 500 m/1 inch.

Next, each spun yarn was mixed with 17.5% by weight of hydrochloric acid and 17.5% by weight of hydrochloric acid.
% by weight of formaldehyde at 35°C.
The temperature was raised to 100°C over 2 hours, and the temperature was increased to 98°C.
A temperature of ˜102° C. was maintained for 10 hours. Each cured fiber thus obtained was mixed with 2.0% by weight of ammonia and 50% by weight.
6 in a mixed aqueous solution consisting of methanol at a temperature of 60°C.
After processing for 0 minutes, it was washed with water and dried. The fineness, breaking strength, and breaking elongation of the cured phenolic fibers obtained as described above were measured.

The results are shown in Table 4. The measurement method for each physical property in Table 4 is as follows.

Breaking strength: A test yarn with a length of 2 (1-JmoV!) is pulled at a speed of 20 min/min, and the load applied at the point when the yarn breaks is measured.

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.

Example 2 [Manufacture of novolac] Manufacture of resols 30 parts of a 10% oxalic acid aqueous solution was added to each of the resols obtained in B-1 to B-10, transferred to an acidic environment, and reacted at 98°C for 2 hours. I did this.

The obtained reaction product was heated and dehydrated until the temperature inside the system reached 170°C, and further heat-treated for 1 hour under reduced pressure of 10 mmHg maximum to obtain a novolak.

Various physical properties of this resin were measured according to the above Example 1,
The results are shown in Table 5.

[Fiber manufacturing]

Next, Novolaks 19 to 28 obtained as described above were melt-spun in exactly the same manner as in Example 1, and then hardened.

The physical properties of the obtained cured yarn were measured in the same manner as in Example 1, and the results are shown in Table 6.

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, the mixture was dehydrated by heating until the temperature in the system reached 170° C., and then heat-treated for 1 hour under reduced pressure of 10 mmHg maximum to obtain a linear novolac (novolac name; abbreviated as linear novolac).

Various physical properties of this resin were measured in the same manner as in Example 1, and the results are shown in Table 7. [Manufacture of fiber] This resin was melt-spun and cured in the same manner as in Example 1 to prepare a thread, and its physical properties were measured.

The results are also listed in Table 7. As is clear from the comparison of Tables 4, 6, and 7, the yarns cured using the novolac of the present invention have better physical properties, especially their breaking strength, than those made using the conventional linear novolac. and the elongation at break has been significantly improved.

Example 3 [Production of novolacs] Novolacs 1 to 18 were produced in the same manner as in Example 1.

[Fiber manufacturing]

Next, using the novolak obtained as described above, melt spinning and curing treatment were carried out in exactly the same manner as in Example 1, except that the curing treatment was held at a temperature of 98 to 102°C for 20 hours.

The physical properties of the obtained cured yarn were measured in the same manner as in Example 1, and the results are shown in Table 8. Example 4 [Production of novolacs] Novolacs 1 to 18 were produced in the same manner as in Example 1.

[Fiber manufacturing]

Next, using the novolak obtained as described above, melt spinning and curing treatment were carried out in exactly the same manner as in Example 1, except that the curing treatment was held at a temperature of 98 to 102°C for 30 hours.

The physical properties of the obtained cured yarn were measured in the same manner as in Example 1, and the results are shown in Table 9.

Example 5 [Production of novolacs] Novolacs 19 to 28 were produced in the same manner as in Example 2.

[Fiber manufacturing]

Next, using the novolak obtained as described above, melt spinning and curing treatment were carried out in exactly the same manner as in Example 1, except that the curing treatment was held at a temperature of 98 to 102°C for 20 hours.

The physical properties of the obtained cured yarn were measured in the same manner as in Example 1, and the results are shown in Table 10. Also, as is clear from the comparison of Tables 4, 8, and 9, or the comparison of Tables 6 and 10, the longer the curing treatment time, the more
It can be seen that fibers with excellent breaking strength can be obtained.

Reference Example Using the cured phenol fibers obtained in Experimental Blacks 1 to 3 and 19 to 21 of Examples 1 and 2 and Experimental Black 29 of Comparative Example 1,
A spun yarn with a single yarn count of 20 was obtained.

The physical properties of each of these spun yarns were measured, and the results were reported in the 11th
Shown in the table. The measurement method for each physical property in Table 11 is as follows:
It is as follows.

Breaking strength: Breaking elongation according to JIS-LlO74, , / L. O. I value; LimitedOxgenIndexJ
As already shown, the phenolic fiber obtained by the method of the present invention using IS-K72Ol was excellent in both strength and elongation even as a single yarn, but as is clear from Table 11, when it was made into a spun yarn, the effect was much lower. It was noticeable.

[Brief explanation of the drawing]

1 and 2 are infrared absorption spectra of Novolaks 5 and 10 obtained in Example 1, respectively. In the figure, the horizontal axis shows the wave number, and the vertical axis shows the transmittance (%).

Claims (1)

[Scope of Claims] 1. A method for producing phenolic resin fibers or films by melt-spinning or film-forming a phenolic resin and then curing it with an aldehyde, wherein the phenolic resin is a neutral or acidic resol. Using novolak obtained by reacting with phenols under the following conditions,
and curing with the aldehydes in the presence of an acidic catalyst,
A method for producing a phenolic resin fiber or film, which is carried out by raising the temperature from 20 to 40°C to 80 to 130°C over 1 to 5 hours, and maintaining the temperature at that temperature for an additional 5 to 50 hours. 2. The manufacturing method according to claim 1, wherein the acidic catalyst used in the curing with the aldehyde is hydrochloric acid.