Wholly aromatic synthetic fibers spun from liquid crystal polymer solution, a method of obtaining such fibers and the use of such fibers

 

The invention relates to the technology of wholly aromatic synthetic fibers electrical components and can be used to produce paper, prepreg and printed circuit boards. Wholly aromatic synthetic fibers spun from liquid-crystalline polymer solutions, have the size of the crystal (plane 110) not more thanand the content of ionic substances is not more than 1.0 wt.%. These fibers have a low content of ionic substances while maintaining the inherent high heat resistance and high young's modulus. The method of obtaining such fibers includes the formation and neutralization of sulfuric or postinoculation solution polyparaphenyleneterephtalamide, regulating the moisture content of the obtained fibers to 15 to 300 wt.% and deionizers processing with heat or without. From fibers to become insulating and discoveredlacoste materials, cord, fabric, sheet-like structure for printed circuit boards. Fibers have superior insulating properties and other operational characteristics. 7 C. and 7 C.p. f-crystals, 2 tab.

The invention relates to wholly aromatic synthetic fibers spun and is skoe ion content, high young's modulus, good dimensional stability, excellent heat resistance and insulating properties; the method of their derivation and use of these fibres.

Wholly aromatic synthetic fibers spun from liquid-crystalline polymer solutions was previously used as a technical fibers or fibers for fabrics for special purposes because of their excellent heat resistance and a high young's modulus. Polyparaphenyleneterephtalamide (PFTA) fiber and poliparafenilenvinilena (PBO) fibers, for example, is known as representatives of such wholly aromatic synthetic fibers spun from liquid-crystalline polymer solutions.

In accordance with a known method of obtaining PPTA and PBO fibers polymers are translated into the liquid-crystalline state with a strong acid, which is used as a solvent for dissolving polymers to obtain a spinning solution, and then subjected to shearing force provided by Villeroy when molding the fiber vysokomaslichnoy orientation. Immediately after spinning svezhevorovanny fibers are washed with water and treated with sulfuric acid or fosforo, dried upset and heat treated at temperatures not lower than 150oWith and then wound in the form of filaments (from U.S. patent 3767756 and 5296135).

U.S. patent 3869430 (Japanese patent publication 14567/1984) also considers a method of producing filaments, where svezhevorovanny fibers spun from liquid crystal polymer solution, subjected to a neutralizing treatment with alkali and then washed with water. The size of the crystal polyamide fibers to heat treatment, which are obtained according to the same patent, exceedas calculated on the basis of radiographic techniques specifically described here.

Thus obtained contain fiber, as used here, the salt or salts formed during neutralization, and usually the salt content of the fibers is in the range of 0.5-3 wt.%. For example, when sulfuric acid is used as solvent and sodium hydroxide is used to neutralize ions, the components of salt, are mainly PA+and SO4-2and their molar ratio is approximately 2:1.

This salt is able to dissociates in the presence of water, when the fibers are used in the conditions of increasing the change there, where required insulating properties.

On the other hand, it is known that paper, rope, cord or fabric, obtained from PPTA or PBO fibers exhibit excellent characteristics such as good dimensional stability, processability, high young's modulus and low shrinkage at high temperature treatments attributable to their polymeric structures, as insulation and nuscodebetting materials when used as elektronasosnyh materials. However, when used in applications requiring vysokodotatsionnyh characteristics, such as the material for the substrate electric circuit, there is the possibility that ionic substance causes the migration, as described above, which imposes constraints on the development of additional applications.

The aim of the present invention is to solve the above problems in the existing technology and the creation of a wholly aromatic synthetic fibers spun from liquid-crystalline polymer solutions, while maintaining high heat resistance and high young's modulus inherent in the wholly aromatic synthetic fibers, such as PPTA and PBO fibers also have a low ion content is I and their applications. Summary of the invention.

The purpose of this invention is to provide a wholly aromatic synthetic fibers spun from liquid crystal polymer solution, the method of their production and their use, which differ in characteristics, summarized in the following: (1) wholly aromatic synthetic fibers spun from liquid-crystalline polymer solutions have the size of the crystal (plane 110)or less and a content of ionic substances to 1.0 wt.% or less; (2) wholly aromatic synthetic fiber according to p.(1), where the specified wholly aromatic synthetic fiber pradesa of liquid crystalline polymer solution is polyparaphenyleneterephtalamide fiber; (3) wholly aromatic synthetic fiber according to p.(1), where the specified wholly aromatic synthetic fiber pradesa of liquid crystalline polymer solution is poliparafenilenvinilena fiber; (4) wholly aromatic synthetic fiber according to any one of paragraphs.(1) to(3), the moisture content is in the range of 15 to 300 wt.%; (5) wholly aromatic synthetic fibers, to the tional processing; (6) wholly aromatic synthetic fiber having a crystal size greaterwhich is obtained by heat treatment of the fiber under item(5); (7) the method of obtaining polyparaphenyleneterephtalamide fibers, which is characterized by spinning and neutralization of the sulfuric acid solution polyparaphenyleneterephtalamide, regulation of the moisture content of the obtained fibers to 15 to 300 wt.% and then Deianeira processing without heat treatment; (8) the method of obtaining polyparaphenyleneterephtalamide fibers, characterized by heat treatment polyparaphenyleneterephtalamide fibres obtained by way of getting under item(7), at a temperature of 150-500oC; (9) the method of obtaining poliparafenilenvinilena fibers, which is characterized by spinning and neutralization postinoculation solution paraphenylenediamine, adjusting the moisture content of the obtained fibers to 15 to 300 wt.% and then holding them Deianeira processing without heat treatment;
(10) the method of obtaining poliparafenilenvinilena fibers, characterized by heat treatment poliparafenilenvinilena fibres obtained by way of getting under item(9), at a temperature of 150-700o;
(11) insulating the fiber, described in paragraph(5);
(12) cord, characterized in that it contains wholly aromatic synthetic fibers, which are described in paragraph(5);
(13) fabric, characterized in that it contains wholly aromatic synthetic fibers, which are described in paragraph(5);
(14) leaf structure for the substrate electric circuit, characterized in that it contains wholly aromatic synthetic fibers, which are described in paragraph(5).

Hereinafter the invention is described in more detail.

This invention provides a wholly aromatic synthetic fibers spun from liquid-crystalline polymer solutions, which have the size of the crystal (plane 110)or less and a content of ionic substances to 1.0 wt.% or less.

Used here, the term "wholly aromatic synthetic fibers spun from liquid-crystalline polymer solutions" means synthetic fibers obtained by spinning of liquid crystalline solution fully aromatic polymer or copolymer, such as a wholly aromatic polyamide. Type wholly aromatic polymer or copolymer critically is not limited, if it recognita predpochtitelnye as wholly aromatic fibers, obtained by the spinning of liquid crystalline solution, in particular, the first of the two, i.e. PPTA fibers are the most desirable. Accordingly, hereinafter the invention is described in relation mainly to PPTA fibers, but you should understand that the invention does not imply a limitation only PPTA fibers, but is similarly applicable to any other wholly aromatic synthetic fibers obtained by spinning of liquid crystalline solutions of fully aromatic polymers or copolymers.

PFTA used in the present invention is a polymer obtained, for example, by polycondensation of terephthalic acid and paraphenylenediamine, which may contain a minor amount of other dicarboxylic acid and/or diamine, copolymerizing in it. Typically, the polymer or copolymer preferably has srednekamennogo molecular weight in the range of 20000-25000.

PBO is a polymer obtained, for example, by polycondensation of terephthalic acid and diaminobenzene, and usually the resulting polymer has srednekamennogo molecular weight 30000-50000.

Forming PPTA or PBO fibers may be spinning their zhidkokristal the acid or phosphoric acid with the formation of a viscous solution, containing 18-20 wt.% such a polymer, passing the solution through the die plate and spinning in a gaseous environment such as air, nitrogen, argon, helium, carbon dioxide or the like, which fills the narrow gap between Villeroy and coagulating bath, and then in the water, which is used as a coagulant. In this case, the shear rate at the time of exit from the die, preferably, is 25000-50000 with-1. When the polymer is PFTA, fiber, consistently coagulated in a spinning bath, subjected to a neutralizing treatment with an aqueous solution of sodium hydroxide and then dried at 100-150oWith, preferably, within 5-20 C. When using PBO, fiber, coagulated in a spinning bath, washed with an aqueous solution of phosphoric acid and water and then dried.

Thus obtained wholly aromatic synthetic fibers typically have a size of crystalor less, preferably, in the range ofWhen such fibers thermoablative at temperatures in the range of 150-700oWith, preferably 150-500oWith their crystal size exceedsusually becoming the procedure is termoobrabotki is usually in the range of 15 to 300 wt.%, in particular 20-70 wt.%
According to the present invention wholly aromatic synthetic fibers spun from liquid-crystalline polymer solutions, as described above, for example, PFTE or PBO fibers preferably have a content of ionic substances is not more than 1.0 wt.%, more preferably, not more than 0.5 wt.%, intr li not more than 0.2 wt.% before heat treatment. The adjustment of the content of ionic substances in the fibers can be, for example, by regulating the concentration values specified in an aqueous solution of sodium hydroxide or phosphoric acid used for neutralization of spun fibers, or conditions (e.g., temperature, time) neutralizing treatment, and/or by implementing Deianeira processing of fibers.

Used here, the term "ionic substance" refers to such substances, which are easily electrolyzed in a polar solvent such as water or ammonia, with the formation of ions, for example, PA+To+etc. as examples of such substances may be mentioned salts such as sodium sulfate, sodium chloride, sodium phosphate and calcium sulfate. These ionic substances consist mainly of strong acids and neutralizing agents, ipoleco defined, that provides the definition of the content of ionic substances on the amount of alkali metal, forming a salt.

Deianeira processing wholly aromatic synthetic fibers to heat treatment, as obtained above, can be carried out as follows. For example, wholly aromatic synthetic fibers that were spun as described above, the crystal size, moisture content, etc. which are adjusted, they can be washed or extracted with water at a temperature of about 20oC for at least 5 minutes, preferably from 30 minutes to 1 o'clock This Deianeira processing the content of the ionic substance fibers may be reduced to not more than 0.2 wt.%.

Thus obtained wholly aromatic synthetic fibers with a low content of ionic substances then thermoablative at 150-700oWith, preferably 150-500oWith the result that the size of the crystal is adjusted to not less thanpreferably in the range of
Thus obtained wholly aromatic synthetic fibers with a low content of ionic substances, which are respectively termoobrabotannyj, ISOE is in accordance with the present invention, cut to short length, can be mixed, for example, a binder formed from termotorgmash resin, or will be dissolved particles or staple fibers in a predetermined ratio, dispersed in water and recycled papermaking method, known reg se, obtaining fibrous paper. This fibrous paper shows excellent properties of wholly aromatic synthetic fibers and has a high insulating properties, because the content of ionic substances such as sodium sulfate, is low. The combination of these properties provides the best paper for use in electric and electronic parts.

Wholly aromatic synthetic fibers of the present invention are also used for receiving the cord, textiles, knitted fabrics, such as nonwoven fabric, and, in addition, leaf patterns for the substrate electric circuit, using their superior properties. In particular, by additional processing of the specified fiber paper containing wholly aromatic synthetic fiber with low content of ionic substances of the present invention, by providing in St. it is abode on the calender, impregnation termotorgmash epoxy resin with the formation of the prepreg and laminating and molding the prepreg with the receiving substrate electrical circuit, can be obtained sheet-like structure for the substrate electric circuit with excellent insulating characteristics.

Hereinafter the invention is described more specifically using examples. The physical characteristics specified in the examples are determined by the following methods.

(a) the Content of ionic substances.

If we take as an example PFTA, conventional ionic substance contained in it is sodium sulfate. Metallic sodium in the specified salt is determined by the following method.

Approximately 0.5 g of sample fibers take on a platinum plate, dissolved in sulfuric acid and with gas burners and electric Cabinet receive the ashes. Thus obtained ash is heated with sulfuric acid, nitric acid and hydrofluoric acid for decomposition. The decomposition product is dissolved in dilute nitric acid to obtain a solution of constant volume. Determination of metallic sodium in a solution of constant volume is carried out using an atomic absorption spectrochemical analysis.

< 20 min, incubated for 5 min in normal condition and weighed again.

The specified moisture content is the moisture content relative to the dry state, calculated by the equation below:

(C) the Size of the crystal.

Get samples of size 4 cm in length each and a mass of 20 mg, hardened colloid solution, where receive data using wide angle x-ray method (diffractometer). On the thus obtained data 2/intensity expect the crystal size, the half value width in the plane 110 according to the sherrer equation.

(d) the reliability of the insulation after moisture absorption.

Wholly aromatic synthetic fibers obtained by the method of this invention or by other means, cut into staple fiber, processed by hot press in fibrous paper on paper the way with a binder, is impregnated with the varnish composition of epoxy resin and dried to obtain a prepreg, which serve as substrates for printed circuit boards. Substrate laminated and molded in a printed circuit Board with copper foil, having a combined electrode. These printed circuit boards relative humidity with the application of the DC voltage of the 20th Century Thus treated PCB return to their normal state in an atmosphere with a temperature of 20oC and 60% relative humidity. The DC voltage 35 V is applied for 60 s to the combined electrodes printed circuit boards, which are left in an atmosphere with high temperature and high humidity for 0 h, 500 h and 1000 h with the determination of the values of insulation resistance, and each minimum value of insulation resistance is logged.

Example 1
One (1) kg PFT (molecular weight: approximately 20,000), obtained in the usual way, is dissolved in 4 kg of concentrated sulfuric acid, passed through a die plate having 1000 holes with a diameter of 0.1 mm, shear rate 30000-1, spun in water with a temperature of 4oC, then subjected to neutralization treatment in 10% aqueous solution of sodium hydroxide in 10oC for 15 s and then the low-temperature drying at 110aboutWith over 15 with obtaining wholly aromatic synthetic fibers, not yet subjected Deianeira processing.

The properties of these wholly aromatic synthetic fibers shown in the table.1.

These wholly aromatic synthetic fibers without as the existing heat treatment at 400oC for 30 s

Physical properties of these heat-treated deionized and wholly aromatic synthetic fibers shown in the table.1.

Thus obtained in example 1, the fibers are cut into staple fibers and processed into fibrous paper together with a binder. The paper is pressed by hot pressing on the calender and impregnating varnish of the epoxy resin and dried to obtain a prepreg used for receiving the printed circuit Board. Prepregs laminated and molded in the PCB. The result of the evaluation of their insulation resistance shown in the table.2.

Comparative example 1
Repeat example 1, except that the sample subjected to heat treatment at 180oWith in 15 seconds immediately after the neutralization treatment, and low-temperature drying is eliminated.

The physical properties of the thus obtained wholly aromatic synthetic fibers shown in the table.1.

The fibers are then cut into staple fibers and processed into fibrous paper together with a binder, pressed by hot pressing on the calender, impregnated with varnish termotorgmash epoxy resin and formed into a prepreg used for receiving printed circuit boards. Prepregs l is.2.

Are given in table.1 and 2 the results show that Deianeira processing carried out prior to the heat treatment wholly aromatic synthetic fibers, reduces the content of ionic substances mentioned fibers and provides wholly aromatic synthetic fibers with superior insulation properties.


Claims

1. Wholly aromatic synthetic fibers spun from liquid-crystalline polymer solutions, characterized in that they have the crystal size calculated by the half value width in the plane 110 according to the sherrer equation,or less, and the content of ionic substances to 1.0 wt.% or less.

2. Wholly aromatic synthetic fibers under item 1, characterized in that the mentioned wholly aromatic synthetic fibers spun from liquid crystal polymer solution are polyparaphenyleneterephtalamide fiber.

3. Wholly aromatic synthetic fibers under item 1, characterized in that the mentioned wholly aromatic synthetic fibers spun from liquid crystal polymer solution are G of PP.1-3, characterized in that the moisture content is in the range of 15 to 300 wt.%.

5. Wholly aromatic synthetic fibers spun from liquid-crystalline polymer solutions, according to any one of paragraphs.1-4, characterized in that the fiber is subjected to Deianeira processing to have the content of ionic substances is reduced to 0.2 wt.% or less.

6. Wholly aromatic synthetic fibers spun from liquid-crystalline polymer solutions, under item 5, characterized in that the fibers have an average crystal size greaterin the subsequent heat treatment.

7. The method of obtaining polyparaphenyleneterephtalamide fibers in PP.1-6, consists in the fact that it includes spinning and neutralization of the sulfuric acid solution polyparaphenyleneterephtalamide, regulating the moisture content of the obtained fibers to 15 to 300 wt.% and the subsequent conduct of their Deianeira processing without heat treatment.

8. The method according to p. 7, consists in the fact that it includes the heat treatment received polyparaphenyleneterephtalamide fibers at 150-500oC.

9. The method of obtaining poliparafenilenvinilena fibers in PP. 1-6, consists in the fact that it includes spinning and n obtained fibers to 15 to 300 wt. % and the subsequent conduct of their Deianeira processing without heat treatment.

10. The method according to p. 9, which consists in the fact that it includes the heat-treated fibers at 150-700oC.

11. Insulation and low dielectric materials, characterized in that they contain wholly aromatic synthetic fibers spun from liquid-crystalline polymer solutions, under item 5.

12. Cord, characterized in that it contains wholly aromatic synthetic fibers spun from liquid-crystalline polymer solutions under item 5.

13. Fabric, characterized in that it contains wholly aromatic synthetic fibers spun from liquid-crystalline polymer solutions under item 5.

14. Leaf patterns for printed circuit boards, characterized in that they contain wholly aromatic synthetic fibers spun from liquid-crystalline polymer solutions under item 5.

 

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