JPH07279084A - Heat-resistant felt - Google Patents

Abstract

PURPOSE:To obtain a heat-resistant felt in the form of nonwoven fabric by using heat-resistant new fibers having a highly favorable combination of prescribed properties of industrial heat-resistant felts used for e.g. a papermaking implement, i.e., heat resistance and physical and mechanical durability for weaving the base fabric and/or web. CONSTITUTION:This heat-resistant felt consists of a base fabric, or is composed of a base fabric and web(s) laminated on one or both of the surfaces of this base fabric. Part or the whole of each of the base fabric and the web(s) comprises heat-resistant fibers which are produced by melt spinning of a thermoplastic resin consisting mainly of an aliphatic polyamide having aromatic ring in the main chain (nylon 6-T) obtained by polycondensation between hexamethylenediamine and terephthalic acid.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an aliphatic polyamide having an aromatic ring in its main chain (referred to as nylon 6-T), which has excellent heat resistance (heat distortion resistance at high temperature, heat deterioration resistance; the same applies hereinafter). The present invention relates to a heat resistant felt used for a part or all of a base fabric composed of a part or all of a heat resistant fiber obtained by melt spinning a resin and / or a web formed on one side or both sides of the base fabric. Particularly in the fiber materials for papermaking tools used in the papermaking field, in detail, such as press felt used in Yankee dryer, multi-cylinder dryer, hot pressing, press drying, impulse drying, etc. The present invention relates to a felt for a high-temperature press, a press-dry (dry felt, canvas) used in a dry part, and a heat-resistant felt used for various industries.

[0002]

2. Description of the Related Art Conventionally, fiber materials for papermaking tools used in the field of papermaking include fibers such as woolen yarns, monofilaments, multifilaments and the like used for weaving base cloth, and opened short fibers (steel). -Pull fiber-) is used as a web sheet and laminated on one side or both sides of a base fabric, and is mainly used for needle punching. Suitable examples of the fiber material are nylon 6, nylon 66, nylon 46, nylon 11 and nylon 12, which are aliphatic polyamides.
Nylon 610, Nylon 612, Nylon 1212,
Alternatively, a general-purpose fiber having a relatively low heat melting temperature such as copolymerized nylon such as nylon 6/66 and polyethylene terephthalate (PET) is used.

On the other hand, acrylic, aramid, PPS, PE
Fibers with a high heat melting temperature such as EK and PI have poor physical and mechanical durability (compaction fatigue, abrasion resistance, fiber splitting / cracking; the same applies below), and in particular they are used for high temperature press felts. The value is extremely low. As a web constituting a felt for a paper machine in JP-A-5-214694, nylon 10-T,
Nylon 12-T has been proposed, but no technique contributing to heat resistance has been obtained. Further, in Japanese Patent Application Laid-Open No. 4-41792, there is proposed a wear-resistant endless paper-making fabric made by weaving a copolymerized nylon monofilament of nylon 6 and nylon 6-T. It was still not sufficient in that it did not take any means to bring it out sufficiently.

Generally, a papermaking tool is of a type in which webs formed by opening crimped fibers are laminated on a woven base fabric and entangled by a nidle punching method, and the required characteristics are required. Must have an extremely high press load and friction and wear resistance associated with high speed running. On the other hand, so-called high-temperature pressing technology has been developed with the aim of improving the dryness and texture of the web, and there is a demand for papermaking tools that have both heat resistance and physical and mechanical durability. .

However, press felts used in Yankee dryers and multi-cylinder dryers, and press dry used in dry parts (dry felt, canvas),
Alternatively, the heat-resistant surface of the papermaking tool, which has been conventionally used in high-temperature pressing, is a general-purpose fiber such as nylon, polyester (PET), acrylic, aramid, PPS, PEEK, or PI, or a conventional heat-resistant fiber. Not only in terms of physical and mechanical durability, it is hard to say that they are still exerting sufficient functions, and the emergence of a papermaking tool having these required characteristics has been awaited.

[0006]

DISCLOSURE OF THE INVENTION The present invention is a heat-resistant fiber made of a new fiber having a high degree of required properties as an industrial heat-resistant felt for the above-mentioned papermaking tools, that is, heat resistance and physical and mechanical durability. It is an object of the present invention to provide a non-woven fabric heat-resistant felt (hereinafter referred to as heat-resistant felt) that is used as a base fabric and / or a web.

[0007]

DISCLOSURE OF THE INVENTION As a result of earnest studies to achieve the above object, the present inventors have found that heat-resistant nylon 6-T fiber is a papermaking tool in all aspects.
In particular, they have found that the heat-resistant felt is suitable for papermaking and the like, and completed the present invention. That is, the heat-resistant felt used for the base cloth and / or the web of the heat-resistant fiber obtained by melt-spinning the thermoplastic resin containing nylon 6-T as the main component of the present invention is as follows.

An aliphatic polyamide (hereinafter referred to as nylon 6-T) having an aromatic ring in the main chain, which is polycondensed with hexamethylenediamine and terephthalic acid and whose chemical structure is represented by the following general formula, is mainly used. A base fabric composed of a part or all of a heat-resistant fiber obtained by melt-spinning a thermoplastic resin as a component, and / or a part or all of a web formed on one side or both sides of the base fabric, the heat-resistant fiber. It is a heat-resistant felt composed of.

[Chemical 1]

In addition, the present invention is based on the chemical structure represented by the following general formula: 1 to 20% by weight of an aliphatic polyamide (hereinafter referred to as PA) component and 99 to 80% by weight of a nylon 6-T component. Part of a web formed by weaving a base fabric with a part or all of heat-resistant fibers obtained by melt-spinning a thermoplastic resin containing a block copolymer as a main component, and / or forming one or both sides of the base fabric. Alternatively, it is a heat-resistant felt made entirely of the heat-resistant fiber.

[Chemical 2] However, PA has the general formula _{- [- NH (CH 2)} m CO -] n - m: 1~11 n: ring-opening polymerization of cyclic lactam represented by the repeating unit or the formula - [- NH (CH _{2) m NH -CO (CH 2) n} CO -] l - l: repeating units m: 1 to 11 n: a polycondensate of a diamine and a dicarboxylic acid represented by 1 to 11.

Further, according to the present invention, a heat-resistant fiber obtained by melt spinning a thermoplastic resin containing nylon 6-T as a main component and 1 to 20% by weight of PA component and 99 to 9% of nylon 6-T component.
80% by weight of a block copolymer as a main component, a base fabric made by mixing and weaving a heat-resistant fiber obtained by melt-spinning a thermoplastic resin, and / or a base fabric obtained by mixing the heat-resistant fiber. Is a heat-resistant felt that constitutes a part or all of a web formed on one side or both sides.

The heat-resistant fiber constituting the heat-resistant felt has an amount of carboxyl end groups larger than that of amino end groups, and the difference is within the range of 5 to 30 meq / kg. And
The heat-resistant felt comprises a phenolic antioxidant represented by a hindered phenol in a thermoplastic resin.

The heat-resistant felt according to the present invention is obtained by weaving a part or all of the above-mentioned heat-resistant fibers into a base cloth, and / or making the heat-resistant fibers into a web with an opening machine, and then weaving the web onto the woven base cloth. Are laminated and obtained by the needle punching method. In order to obtain the heat resistant fiber, a commonly used melt spinning method is suitable and there is no particular limitation, but the key is to maintain a melt viscosity applicable to melt spinning. The present inventors have found that the melt flow rate (hereinafter referred to as MFR) according to the JIS K7210 A method for flow test of thermoplastics is one of the applicable melt viscosities, and this has been found out. Suggest as follows:

That is, the length of the steel die is 8 mm, the die inner diameter is 2
mm, test load 1kgf, MFR at a set temperature of 350 ℃ is measured, and the measured value is 1 to 100g / 10min, preferably 50 to
Prepare a thermoplastic resin having a degree of polymerization such that the thermoplastic resin falls within the range of 75 g / 10 min. The thermoplastic resin containing the block copolymer as a main component takes into consideration not only the heat resistance but also the physical and mechanical durability, and the PA segment component constituting the block copolymer is described below. Is 1 to 20% by weight and the nylon 6-T component is in the range of 99 to 80% by weight, and it is needless to say that the degree of polymerization is adjusted to be in the range of the MFR. .

Next, the aliphatic polyamide (referred to as PA) which constitutes the block copolymer has the general formula

[Chemical 3] (M = 3 to 11) represented by ε-capramide, poly-ω-
Polyamide obtained by ring-opening polymerization from ω-amino acid such as nonamide, poly-ω-laurinamide or ω-lactam, or polyhexamethylene adipamide, polytetramethylene adipamide, polyhexamethylene sebaca It is a polyamide obtained from a diamine such as amide and a dicarboxylic acid, or a copolymer of these constituent components, or a blend of various copolymers thereof.

To give a concrete example of the designation of nylon, nylon 4, nylon 6, nylon 8, nylon 11, nylon 12, nylon 46, nylon 66, nylon 6
10, Nylon 612, Nylon 1212, and other aliphatic polyamides, or Nylon 6/66, Nylon 6 /
An aliphatic copolyamide such as 610 can be used.

The PA segment component constituting the block copolymer is 1 to 20% by weight, and the nylon 6-T component is 99 to
Copolymerization in the range of 80% by weight is an important requirement for achieving the present invention. Those that deviate from this range do not have heat resistance, physical or mechanical durability. For example,
When the proportion of the PA segment component exceeds 20% by weight, the heat resistance is deteriorated, and when the block copolymer is formed into a fiber by the melt spinning method, a yarn breakage such as a single yarn breakage or a yarn breakage is deteriorated. .

On the other hand, depending on the ratio of the constituents of the block copolymer, there is a tendency that heat resistance and physical and mechanical durability conflict with each other. This is embodied as follows.

[Table 1] The reason for this is not clear, but the PA segment forms an amorphous site in the block copolymer and serves as an elastic soft segment-like element, while nylon 6-T segmet forms a crystalline site and forms a hard site. It can be inferred that it is responsible for segmental elements. That is, the element that realizes the heat resistance is the nylon 6-T hard segment, and conversely, the PA soft segment that realizes the physical and mechanical durability.

The proportions of the respective components of the block copolymer which can be used in the present invention are within the above-mentioned ranges, and particularly for papermaking applications, they are preferably used in a Yankee dryer and a multi-cylinder dryer. In the case of the press felt, the PA segment is about 20% by weight or less, and in the case of a high-temperature press felt such as hot pressing, press drying or impulse drying, the PA segment is about 5% by weight or less, and it is used in the dry part. In the case of press dry (dry felt, canvas), about 10% by weight or less is suitable.

Further, as an important factor for exerting the effect of the present invention, heat-resistant fibers melt-spun from a thermoplastic resin containing nylon 6-T as a main component, and an aliphatic polyamide (PA) component and nylon 6 are used. There is adjustment of the amount of carboxyl terminal groups and the amount of amino terminal groups of heat resistant fibers produced by a melt spinning method from a thermoplastic resin containing a block copolymer containing -T as a main component. That is, in the heat-resistant fiber, the amount of carboxyl end groups is larger than the amount of amino end groups, and the difference must be within the range of 5 to 30 meq / kg.

Usually, the amount of each of carboxyl end groups and amino end groups of PA, nylon 6-T, aromatic polyamide (hereinafter referred to as aramid), etc. is 30 to 100 meq / kg.
It is widely known that the physical properties are significantly reduced while yellowing, thermal decomposition reaction and cross-linking reaction are caused by thermal oxidation because the amounts are almost equal in the range. The mechanism of such deterioration undergoes a complicated process leading to hydrogen abstraction, cleavage, and molecular cleavage under the action of heat, light, and oxygen. The use of stabilizers), i.e. radical chain inhibitors, is suitable. However, the use of the antioxidant alone cannot sufficiently satisfy the function of the heat-resistant felt using the heat-resistant fiber as intended by the present invention. That is, the heat-resistant felt of the present invention has more carboxyl end groups than amino end groups, and the difference is 5 to 30 meq.
By using the heat-resistant fiber in the range of / kg, the function can be enhanced to a level sufficiently satisfying as a papermaking tool.

The control of the amount of the molecular terminal group achieved in the present invention is a molecular terminal adjuster at the time of polymerization, as a monocarboxylic acid such as acetic acid and benzoic acid, a dicarboxylic acid such as adipic acid, sebacic acid and terephthalic acid, and / or Or heterocyclic compounds such as triazines, piperazines and pyrimidines, or N, N-dimethylformamide, N, N-dimethylacetamide, hexamethyleneadipamide, hexamethylenesebacamide, hexamethyleneterephthalamide, etc. The amide compounds of 1) and imide compounds such as mono-biscarbodiimide are suitable. Regarding the molecular end modifier, generally, in the process of polymerizing the thermoplastic resin, a method in which the molecular end modifier is mixed and stirred immediately before the completion and then the polymer is discharged from the polymerization kettle is adopted.

The regulator for controlling the amount of the molecular end groups is a compound known per se, and is disclosed in JP-B-3-4.
As described in Japanese Patent No. 7326, a method of blocking the carboxyl end group of the polyester fiber, or a method of blocking the amino end group of the polyamide fiber, which is not specified, is known, and adjustment of these carboxyl end group and amino end group is a chemical method. Although effective for improving stability, it is different from the present invention in terms of action and effect.

That is, the amount of carboxyl terminal groups of the heat resistant fiber made of the thermoplastic resin of nylon 6-T is larger than the amount of amino terminal groups, and the difference in the amount of molecular terminal groups is 5 to 5.
The heat-resistant felt of the present invention using heat-resistant fibers in the range of 30 meq / kg has a great advantage that it can be used even under thermal conditions without causing yellowing, thermal decomposition reaction or crosslinking reaction. There is. The reason for this is not clear, but it is considered that there is an intermolecular interaction, that is, in the state where the amount of the carboxyl end groups is larger than that of the amino end groups, the amino end groups are blocked by the carboxyl end groups of the adjacent molecules. On the other hand, the amount of carboxyl end groups is larger than that of amino end groups, and the difference in the amount of molecular end groups is 30 me.
In a heat-resistant felt using heat-resistant fiber of q / kg or more, since the carboxyl end groups involved in intermolecular interaction are excessive, the low-polymerized material remaining in the heat-resistant fiber is The so-called transamidation reaction is likely to occur, which is not suitable for carrying out the present invention.

In the present invention, heat-resistant fibers made of a thermoplastic resin containing nylon 6-T as a main component whose molecular end group amount is adjusted in this manner or a block made of a PA component and a nylon 6-T component. In the case of heat-resistant fibers made of a thermoplastic resin containing a polymer as a main component, in order to further improve its heat resistance, that is, to impart heat stability during fiber production by melt spinning, and heat resistance as a heat-resistant felt. A phenolic antioxidant represented by a hindered phenol may be added to the thermoplastic resin in order to improve the properties.

It is particularly preferable that the thermoplastic resin used in the present invention has a heat melting temperature of more than 300 ° C.
Special attention should be paid to the selection of the antioxidant (heat-resistant stabilizer), and as a result of diligent studies by the present inventors, among phenol-based antioxidants represented by hindered phenol,
2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,6, -di-tert-butyl-p-cresol, 2,2'-methylenebis (4-ethyl-6tert)
-Butylphenol), preferably a high heat-resistant polymer type hindered phenol having a melting point of 200 ° C. or more is useful as an additive in melt spinning. As an example, di- (2-methyl-4-hydroxy-5-tertbutylphenyl) butane (trade name: Adekaskabu AO manufactured by Asahi Denka Co., Ltd.
-40), and / or 1,3,5 trimethyl-2,4,6
-Tri (3,5-di-tert-butyl-4-hydroxybenzyl) benzene (trade name: ADEKA STAB AO manufactured by Asahi Denka Co., Ltd.
-330) is preferable.

The additives may be internally added to the thermoplastic resin between the hopper of the spinning machine and the spinneret.
Therefore, the additive may be added in the hopper or before it. For example, a method in which a thermoplastic resin and additives are mixed and stirred in a mixer and then supplied to a hopper, when the thermoplastic resin is polymerized, the additives are mixed immediately before the end of the polymerization, and after stirring, the polymer is removed from the polymerization kettle. How to pay out, or after completion of polymerization,
In the process of molding the polymer discharged from the polymerization kettle into chips, additives may be added to prepare chips for spinning raw material and stored. Alternatively, a so-called master-batch method may be used in which, when the additive is added to the thermoplastic resin, a master pellet containing the additive in a high concentration is prepared, and further, the mixture is diluted and melt-spun with the resin.

However, it is important that the additives are uniformly dispersed during melt spinning in order to prevent yarn unevenness during spinning, but the compounding ratio of the additives is within the range of MFR of 1 to 100 g /
It is important to keep it in 10 min, preferably 50 to 100 g / 10 min in order to keep the melt viscosity at the time of melt spinning moderately, and it is preferable to use it in the range of 0.5 to 5% by weight with respect to the resin.

In carrying out the present invention, a step of adjusting the amount of molecular end groups and / or an antioxidant (additive)
In each of the blending step and the final melt-spinning step, the molecular end group amount or MFR before and after each step
It is needless to say that, in order to obtain a desired molecular end group amount and the MFR, a degree of polymerization in each step may be required in advance in order to carry out the present invention, since the degree of polymerization represented by is changed. Yes.

In the present invention, in order to more efficiently bring out the effect of a phenolic antioxidant represented by hindered phenol as an antioxidant (heat resistant stabilizer), another antioxidant (heat resistant stabilizer) is used. Agent) may be used in combination. For example, copper compounds such as copper halide and copper acetate, phosphorus-based antioxidants, sulfur-based antioxidants, hindered amines (HALS), benzophenone-based compounds such as 2-hydroxy-4-methoxybenzophenone, triazol-based compounds Compounds such as 2- (2'-hydroxy-3 ', 5'-di-tertbutylphenyl) -5-chlorobenzotriazo-
It is also possible to use an oxazole, an oxazole compound, or an imidazole compound in combination.

The thermoplastic resin containing nylon 6-T as a main component or the thermoplastic resin containing a block copolymer composed of a PA component and a nylon 6-T component as a main component used in the present invention is an object of the present invention. The above-mentioned thermoplastic resin and other thermoplastic resins such as polyphenylene sulfide (PPS) and polyether ether ketone (PEE) within a range that does not impair
K) and a thermoplastic resin obtained by blending a thermoplastic resin having a high melting point such as wholly aromatic polyester in an arbitrary ratio are also included. Weaving a base fabric with heat-resistant fibers formed by melt spinning a thermoplastic resin blended in any of these ratios,
And / or a heat-resistant felt in which a part or all of the web formed on one or both sides of the base fabric is composed of the heat-resistant fiber, the compatibility of the blended resin, melt viscosity, melt spinning method, melt spinning The yarn-forming tone, heat resistance, and physical and mechanical durability at the time of fiberizing by the method must be taken into consideration in accordance with the gist of the present invention.

[0031]

In the present invention, the durability of the above heat-resistant fiber as a heat-resistant felt is adjusted by adjusting the molecular end group amount, that is, the carboxyl end group amount is larger than the amino end group amount, and the difference is 5 to 30 meq / kg. The heat resistance of the heat resistant fiber can be dramatically improved by controlling the molecular end group amount of the heat resistant fiber and / or by using an antioxidant (heat resistant stabilizer).

In Japanese Patent Laid-Open No. 4-2849, ε
A polyamide forming unit derived from caprolactam
A polyamide resin composition comprising 100 parts by weight of a polyamide copolymer containing 99 to 75% by weight and 0.005 to 1 part by weight of a compound having a hindered phenol group and an amide group in the molecule at the same time. Although fishing nets are known, the purpose, use and action of the present invention are completely different from those of the present invention.
That is, the purpose of the above-mentioned Japanese Patent Application Laid-Open No. 4-2849 is to maintain a high level of the physical properties that are lost in the closing process (steaming) of a polyamide fishing net (knitting net), whereas the present invention is heat resistant. The function as a heat-resistant felt is enhanced by adjusting the molecular end group amount of nylon 6-T fiber and / or blending an antioxidant represented by hindered phenol. Further, the action of the antioxidant represented by the hindered phenol of the present invention is different from the invention of the above-mentioned publication in that it does not have a chemical bonding property to polyamide.

In the present invention, a thermoplastic resin containing an aromatic polyamide (nylon 6-T) polycondensed with hexamethylenediamine and terephthalic acid represented by the following formula as a main component

[Chemical 4] And a thermoplastic resin containing as a main component a block copolymer consisting of an aliphatic polyamide (PA) component and a nylon 6-T component represented by the following formula:

[Chemical 5] Melt-spun a thermoplastic resin formed by blending at a desired ratio, weaving a base fabric with the resulting heat-resistant fibers, and / or forming a part or all of a web formed on one or both sides of the base fabric. It may be a heat resistant felt.

The fineness of the heat resistant fiber used in the present invention is 1 to 50 denier, preferably 3 to 25 denier in the case of the short fiber used in the web. On the other hand, when used for a part or all of the woven base fabric, woolen yarn or multifilament composed of short fibers of 3 to 50 denier, or 0.1 to
It is a 1.0 mm monofilament. In the case of short fibers, if it is less than 1 denier, there are many problems in terms of spinnability, and if it exceeds 50 denier, it is unsuitable especially in the field of papermaking considering the influence on the web. Further, in the present invention, the shape of the heat resistant fiber is preferably short fiber (staple fiber) in the papermaking tool. The reason for this is that the papermaking tools are based on the required bulkiness, that is, the crimpability of the fibers.

The heat-resistant felt of the present invention may contain other heat-resistant fibers such as glass fiber, etc. within a range not impairing the object of the present invention.
Inorganic fibers such as carbon fiber and ceramic fiber, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyether imide (PEI), polyimide (PI), meta type, para type aromatic polyamide (para type) It can be mixed with organic fibers such as aramid) and wholly aromatic polyester, but the proportion of these other heat resistant fibers in the heat resistant felt is 40% by weight, preferably
It is important that the amount is 25% by weight or less.

[0036]

EXAMPLES The present invention will be described below with reference to examples. The measuring method of the measured value defined in this example is based on the following conditions, but the present invention is not limited to these. Measurement of melt flow rate It is a melt flow rate (MFR) according to JIS K7210 A method. Steel die length 8mm, die inner diameter 2mm, test load 1kgf, set temperature 350 ℃
The MFR at 1 to 100g / 10mi is measured.
It is necessary to prepare a thermoplastic resin having a degree of polymerization of n, preferably in the range of 50 to 75 g / min.

Quantification of the amount of end groups: The amount of amino end groups and the amount of end carboxyl groups were dissolved in a sample (heat resistant fiber) using phenol and aniline as solvents, respectively, and titrated with hydrochloric acid or sodium hydroxide to conduct conductivity. Determine the amount of end groups by measurement (Polymer Society of Japan “Polymer Test Course 6, Polymer Polymerization Degree Measurement” Kyoritsu (1957) P.223). Alternatively, the following general method may be used. Determination of the amount of amino end groups Dissolve 0.5 g of sample in m-cresol and use it as an indicator.
Titration method with 1 / 10N para-toluenesulfonic acid Determination of the amount of carboxyl end groups Dissolve 0.5g of sample in a mixed solvent of benzyl alcohol / methanol (9: 1) and use 1 / 10N under the indicator. Method of titrating with potassium hydroxide

Example 1 In a step of polycondensing a nylon salt prepared by mixing stoichiometrically required amounts of hexamethylenediamine and terephthalic acid by a conventional method, the obtained nylon 6-T is the main component. Polymerization was terminated by blocking the amino terminal groups with terephthalic acid so that the MFR of the thermoplastic resin was within the range of the measured value of 50 to 100 g / 10 min. The thermoplastic resin containing Nylon 6-T as the main component had an MFR of 75 g / 10 min, the amount of carboxyl end groups was greater than the amount of amino end groups, and the difference was
It was 30 meq / kg. This thermoplastic resin was once extruded into a strand, cut into chips, washed with water and dried to obtain a resin for melt spinning.

Next, in the melt-spinning process, the inside of the system from the hopper to the melt-spinning machine is sufficiently replaced with dry nitrogen gas, and the number of holes is 130 mm with an inner diameter of 13 mm, a spinneret of 0.3 mm and a diameter of 0.3 mm. The preheat temperature in the small extruder (melt spinning machine) was set to 250 ℃, the intermediate temperature was 320 ℃, the melt temperature was 350 ℃, the spinning head temperature was 355 ℃, and the discharge rate of the gear pump was 5.5 g / min.
Melt spinning was performed at a winding speed of 450 m / min, and was rapidly cooled using a cooling chimney cold air provided vertically below the spinneret.

The rapidly solidified yarn was immediately oiled,
In the drawing zone of the first stage, 200 provided between the drawing rollers.
Stretching at a draw ratio of 3.0 times while passing through a box filled with superheated steam at ℃
Stretching was carried out with a stretching zone at 0 ° C. so that the total stretching ratio was 5.5 times, and after further relaxation treatment at a relaxation rate of 5%, the obtained yarns were converged and again oiled, and then passed through a stuffer box. Crimped, then 105 ° C net conveyor-
It was dried with a hot-air penetrating dryer and cut to a fiber length of 76 mm. The final heat-resistant fiber obtained had a fineness of 15 denier. This heat-resistant fiber has more carboxyl end groups than amino end groups, and the difference is 28 meq /
The physical properties of the heat resistant fiber are shown in Table 2.

Next, this heat-resistant fiber was made into a web sheet opened by a card system, and while being laminated on a base fabric made by weaving nylon 6, it was entangled by the nidle punch method, and the final basis weight was obtained. A heat-resistant felt composed of 1000 g / m ² was obtained. Table 3 shows the durability that the heat-resistant felt can exhibit.

Example 2 Hexamethylenediamine and terephthalic acid were mixed in a stoichiometrically required amount to form a nylon salt, which was then polycondensed by an ordinary method by adding an appropriate amount of ε-caprolactam. Shown aliphatic polyamide (PA.6) component and nylon 6
A block copolymer composed of the -T component was obtained.

[Chemical 6] In this polycondensation step, the MF of the thermoplastic resin obtained
The carboxyl terminal group was blocked with isophthalic acid to terminate the polymerization so that R was within the range of 50 to 100 g / 10 min. The block copolymer obtained had an MFR of 75 g / 10 mi.
The amount of n and carboxyl end groups is larger than the amount of amino end groups, the difference is 30 meq / kg, the PA segment component forming the block copolymer is 20% by weight, nylon 6-T
The composition was 80% by weight.

This thermoplastic resin was once extruded into a strand, cut into chips, washed with water and dried to obtain a resin for melt spinning. Preheating temperature in melt spinning machine 230 ℃, intermediate temperature 300 ℃, melt temperature 330 ℃, spinning head temperature 335 ℃
Other conditions were the same as in Example 1, and melt spinning was performed to obtain a heat resistant fiber having a fiber length of 76 mm with 13 denier. The amount of carboxyl terminal groups of the obtained heat-resistant fiber was larger than the amount of amino terminal groups, and the difference was 27 meq / kg. The physical properties that the heat-resistant fiber can exhibit are shown in Table 2. Next, this heat-resistant fiber was made into a web sheet opened by a card method, and while being laminated on a base fabric made by weaving nylon 6, it was entangled by the needle punch method, and the final basis weight was 1000 g / A heat-resistant felt composed of m ² was obtained. Table 3 shows the durability that the heat-resistant felt can exhibit.

Example 3 In the step of polycondensing a nylon salt obtained by mixing stoichiometrically required amounts of hexamethylenediamine and terephthalic acid by a conventional method, the obtained nylon 6-T is the main component. The amino terminal groups were blocked with terephthalic acid to terminate the polymerization so that the MFR of the thermoplastic resin was within the range of 50 to 100 g / 10 min, and then N, N'-bis (2,6-
The carboxyl end groups were blocked with diisopropylphenyl) -carbodiimide.

The thermoplastic resin containing Nylon 6-T as the main component had an MFR of 50 g / 10 min, the amount of carboxyl end groups was larger than the amount of amino end groups, and the difference was 10 meq / kg.
Met. This thermoplastic resin was once extruded into a strand, cut into chips, washed with water, and dried with 100 parts of the resin, which was a hindered phenol 1,3.
5 trimethyl-2,4,6, -tri (3,5-di-tert
1 part of -butyl-4-hydroxybenzyl) benzene (trade name: ADEKA STAB AO-330 manufactured by Asahi Denka Co., Ltd.) was mixed and stirred in a hopper to obtain a resin for melt spinning.

Thereafter, melt spinning was carried out in the same manner as in Example 1 to obtain a final heat resistant fiber having a length of 15 denier and a length of 76 mm. The amount of carboxyl terminal groups of the obtained heat-resistant fiber was larger than the amount of amino terminal groups, and the difference was 7 meq / kg. The physical properties that this heat-resistant fiber can exhibit are shown in Table 2. Next, this heat-resistant fiber was made into a web sheet opened by a card method, laminated on a base fabric made of nylon 6 weave, and mixed by a needle punch method to give a final basis weight of 1000 g / m 2. A heat-resistant felt composed of ² was obtained. Table 3 shows the durability that the heat-resistant felt can exhibit.

Example 4 In the step of polycondensing a nylon salt obtained by mixing stoichiometrically required amounts of hexamethylenediamine and terephthalic acid by a conventional method, the obtained nylon 6-T is the main component. The amino terminal groups were blocked with adipic acid to terminate the polymerization so that the MFR of the thermoplastic resin was within the range of the measured value of 50 to 100 g / 10 min. The thermoplastic resin containing Nylon 6-T as the main component has an MFR of 60 g / 10 min, the amount of carboxyl end groups is greater than the amount of amino end groups, and the difference is 25 m.
It was eq / kg.

This thermoplastic resin was once extruded in the form of a strand, cut into chips, washed with water and dried to 100 parts of the resin, which was a hindered phenol 1,3.
5 trimethyl-2,4,6-tri (3,5-di-tert-
Butyl-4-hydroxybenzyl) benzene (trade name
1 part of Asahi Denka ADEKA STAB AO-330) was mixed and stirred in a hopper to obtain a resin for melt spinning. Thereafter, melt spinning was performed in the same manner as in Example 1 to obtain a final heat-resistant fiber having a length of 15 mm and a length of 76 mm. The amount of carboxyl terminal groups of the obtained heat resistant fiber was larger than the amount of amino terminal groups, and the difference was 20 meq / kg. The physical properties that can be exhibited by this heat resistant fiber are shown in Table 2.
Next, this heat-resistant fiber was made into a web sheet opened by a card system, nylon 6 was woven, and while being laminated on a base fabric, it was entangled by the nidle punch method, and the final basis weight was 1000 g / A heat-resistant felt composed of m ² was obtained. Table 3 shows the durability that the heat-resistant felt can exhibit.

Example 5 Hexamethylenediamine and terephthalic acid were mixed in a stoichiometrically required amount to form a nylon salt, and then an appropriate amount of ε-caprolactam was added and polycondensation was carried out by a conventional method. A block copolymer composed of an aliphatic polyamide (PA.6) component and a nylon 6-T component was obtained in the same manner as in.
In this polycondensation step, the MF of the thermoplastic resin obtained
The amino terminal group was blocked with isophthalic acid to terminate the polymerization so that R was within the range of 50 to 100 g / 10 min in the measured value, and then the carboxyl terminal group was blocked with hexahydropyrazine.

The MFR of the obtained block copolymer resin is
50 g / 10 min, the amount of carboxyl end groups is larger than the amount of amino end groups, the difference is 10 meq / kg, the PA segment component constituting the block copolymer is 20% by weight, and the nylon 6-T component is 80%. % By weight. This thermoplastic resin is once extruded into a strand, cut into chips, and then
Di- (2-methyl-4-hydroxy-5), which is a hindered phenol based on 100 times the resin obtained by washing with water and drying.
1 part of -tert-butylphenyl) butane (Adeka Stab AO-40 manufactured by Asahi Denka Co., Ltd.) was mixed and stirred in a hopper to obtain a melt-spun resin.

Then, melt spinning was performed under the same conditions as in Example 2.
A heat resistant fiber having a fiber length of 76 mm was obtained with 13 denier. The amount of carboxyl terminal groups of the obtained heat-resistant fiber was larger than the amount of amino terminal groups, and the difference was 7 meq / kg. Table 2 shows the physical properties of this heat-resistant fiber.

Next, this heat-resistant fiber was used as a web sheet opened by a card system, nylon 6 was woven and laminated on a base fabric, and entangled by the nidle punch method, and finally A heat resistant felt having a basis weight of 1000 g / m ² was obtained. Table 3 shows the durability that the heat-resistant felt can exhibit.

Example 6 Obtained by forming a nylon salt by mixing hexamethylenediamine and terephthalic acid in a stoichiometrically required amount, and then adding an appropriate amount of hexamethyleneadipamide and polycondensing by a conventional method. Further, in obtaining a block copolymer represented by the following formula, which comprises an aliphatic polyamide (PA.66) component and a nylon 6-T component, the MFR of the thermoplastic resin obtained in the polycondensation step is The carboxyl terminal group was blocked with isophthalic acid to stop the polymerization so that the measured value was within the range of 50 to 100 g / 10 min. M of the obtained block copolymer resin
FR is 65 g / 10 min, the amount of carboxyl end groups is larger than the amount of amino end groups, the difference is 30 meq / kg, and the PA segment component constituting the block copolymer is 10% by weight,
The nylon 6-T component was 90% by weight.

[Chemical 7]

Then, a resin for melt spinning was obtained under the same conditions as in Example 2 and then melt-spun under the same conditions to obtain a heat resistant fiber having a fiber length of 76 mm with 13 denier. The amount of carboxyl terminal groups of the obtained heat resistant fiber was larger than the amount of amino terminal groups, and the difference was 25 meq / kg. The physical properties of this heat resistant fiber are shown in Table 2. Next, this heat-resistant fiber was made into a web sheet opened by a card method, and while being laminated on a base fabric made by weaving nylon 6, it was entangled by the needle punch method, and the final basis weight was 1000 g / m 2. ^The heat resistant felt composed of ² was obtained, and the durability that this heat resistant felt can exhibit is shown in Table 3.
Described in.

Example 7 The heat-resistant fibers obtained in Examples 3 and 5, that is, a thermoplastic resin containing an aromatic polyamide (nylon 6-T) polycondensed with hexethylenediamine and terephthalic acid as a main component was used. A heat-resistant fiber obtained by melt-spinning and a heat-resistant fiber obtained by melt-spinning a thermoplastic resin containing a block copolymer composed of an aliphatic polyamide (PA.6) component and a nylon 6-T component as a main component. , And each of them was blended in a weight ratio of 1: 1.

The amount of carboxyl end groups of this blend fiber was larger than that of amino end groups, and the difference was 7 meq / kg. Next, this heat-resistant blended fiber was made into a web sheet opened by a card method, and while being laminated on a base fabric made by weaving nylon 6, it was entangled by the nidle punch method and the final basis weight was 1000 g. A heat-resistant felt composed of / m ² was obtained. Table 3 shows the durability that the heat-resistant felt can exhibit.

COMPARATIVE EXAMPLE 1 Hexymethylenediamine and terephthalic acid were mixed in a stoichiometrically required amount to form a nylon salt, which was then polycondensed by an ordinary method by adding an appropriate amount of ε-caprolactam. A block copolymer composed of an aliphatic polyamide (PA.6) component and a nylon 6-T component was obtained in the same manner as in.
This thermoplastic resin has an MFR of 90 g / 10 min, a carboxyl end group amount is equal to the amino end group amount, the PA segment component constituting the block copolymer is 30% by weight, and the nylon 6-T component is 70% by weight. %Met.

A hinder was added to 100 parts of this thermoplastic resin.
One part of dophenol di- (2-methyl-4-hydroxy-5-tertbutylphenyl) butane (Adeka Stab AO-40 manufactured by Asahi Denka Co., Ltd.) was mixed and stirred in a hopper to obtain a resin for melt spinning. . Then, melt spinning was performed under the same conditions as in Example 2 to obtain a heat resistant fiber having a fiber length of 76 mm with 13 denier. The amount of carboxyl terminal groups of the obtained heat-resistant fiber was the same as the amount of amino terminal groups, and the physical properties of the heat-resistant fiber are shown in Table 2. Next, this heat-resistant fiber was made into a web sheet opened by a card method, and while being laminated on a base fabric made by weaving nylon 6, it was entangled by the needle punch method, and the final basis weight was 1000 g / m 2. A heat-resistant felt composed of ² was obtained. Table 3 shows the durability that the heat-resistant felt can exhibit.

Conventional Example Commercially available heat-resistant fibers polyparaphenylene terephthalamide (PPTA; Kevlar-49), polymetaphenylene isophthalamide (PMIA; Nomex), polybenzimidazole (PBI; Ceranises) , Polyphenylene sulfide (PPS; PROCON), poly-
Teru-terketone (polyoxy-1,4, -phenyleneoxy-1,4, phenylenecarbonyl-1,4, phenylene; PEEK; IYEX) was used as a card sheet-opened web sheet, and nylon 6 was used. While being laminated on the woven base fabric, it was entangled by the nidle punch method to obtain a heat-resistant felt having a final basis weight of 1000 g / m ² . The durability that the heat resistant fiber and the heat resistant felt can exhibit is shown in Tables 2 and 3, respectively.

[0060]

[Table 2]

[0061]

[Table 3]

[0062]

EFFECTS OF THE INVENTION Since the present invention has the above-mentioned constitution, it is required properties as a heat-resistant felt for industrial use such as papermaking tools, that is, heat resistance and physical and mechanical durability as shown in Tables 2 and 3. It has excellent abrasion resistance and also has resistance to hot press fatigue, and as a heat-resistant felt used in the field of papermaking and the like intended by the present invention, part or all of the heat-resistant fiber made of new fiber is used as a base fabric. And / or the nonwoven heat-resistant felt used for the web can be obtained. Further, the nylon 6-T heat resistant fiber obtained in the present invention is
Since the amount of molecular end groups is adjusted and a suitable antioxidant is added, the fiber strength retention rate after high temperature exposure becomes high.

The heat-resistant fiber obtained by melt-spinning the thermoplastic resin containing Nylon 6-T as the main component of the present invention has a high fiber strength even if it is continuously exposed to an oven at 200 ° C. for 500 hours. The retention rate is high and the effect of heat resistance is sufficient.

A heat-resistant fiber obtained by melt-spinning a thermoplastic resin containing nylon 6-T as a main component was used as an opened web sheet, which was entangled by a nidle punch method while being laminated on a base cloth. For heat-resistant felt, commercially available heat-resistant fibers (PPTA, PMIA, PBI, P
(PS, PEEK) as an opened web sheet, and has less wear amount in a wear test and less hot press fatigue compared to a heat-resistant felt that is entangled by the needle punch method while being laminated on a base fabric. Therefore, the heat-resistant felt used for various industries, particularly the durability of the function as a felt for papermaking, that is, the physical and mechanical properties are high.

A heat-resistant material obtained by melt-spinning a thermoplastic resin containing a block copolymer of 1 to 20% by weight of an aliphatic polyamide component and 99 to 80% by weight of a nylon 6-T component of the present invention as a main component. Even if the functional fiber is continuously exposed to an oven at 200 ° C for 500 hours, the fiber strength retention rate is high and the heat resistance effect is sufficient.

A heat-resistant fiber obtained by melt-spinning a thermoplastic resin containing this block copolymer as a main component was used as an opened web sheet, which was entangled by a nidle punch method while being laminated on a base cloth. For heat resistant felt, commercially available heat resistant fibers (PPTA, PMIA, PBI,
(PPS, PEEK) as an opened web sheet,
Compared to heat-resistant felts that are entangled by the needle punching method while being laminated on a base cloth, the heat-resistant felts used in various industries, especially papermaking, have less wear amount in a wear test and less heat press fatigue. The durability of the function as an industrial felt, that is, the physical and mechanical durability is high. In terms of abrasion resistance, the durability of the function as such a felt for papermaking is more than that of a heat-resistant felt using a heat-resistant fiber formed by melt-spinning a thermoplastic resin whose main component is nylon 6-T. To be enhanced.

The aliphatic polyamide which is a constituent of the block copolymer is a ring-opening polymer of a cyclic lactam (PA.6) or a polycondensate of a diamine and a dicarboxylic acid (PA.6).
Even in 6), the function of the present invention is sufficiently exhibited.

From heat-resistant fibers obtained by melt-spinning a thermoplastic resin containing nylon 6-T as a main component, and 1 to 20% by weight of an aliphatic polyamide component and 99 to 80% by weight of a nylon 6-T component. The heat-resistant fiber made by melt-spinning the thermoplastic resin containing the block copolymer as the main component is blended in a weight ratio of 1: 1.
Even if it was exposed to the oven for 500 hours continuously, the fiber strength retention rate was high and the heat resistance effect was sufficient.

The heat-resistant fibers obtained by blending the heat-resistant fibers are made into opened web sheets, and the heat-resistant felts are entangled by the needle punching method while being laminated on the base fabric. (PPTA, PMIA,
Webshi opened with PBI, PPS, PEEK)
As compared with the heat resistant felt that is entangled by the nidle punch method while being laminated on the base cloth, the wear amount in the wear test is small, and the heat press fatigue resistance is small,
It has high durability as a heat-resistant felt used for various industries, especially as a felt for papermaking, that is, high physical and mechanical durability. In terms of abrasion resistance, the durability of such a function as a felt for papermaking is more excellent than that of a heat-resistant felt using heat-resistant fibers formed by melt-spinning a thermoplastic resin whose main component is nylon 6-T. To be enhanced.

A heat-resistant fiber obtained by melt-spinning a thermoplastic resin containing, as a main component, a block copolymer composed of 30% by weight of an aliphatic polyamide component and 70% by weight of a nylon 6-T component. Fibers having the same amount of carboxyl end groups and amino end groups as those of the fibers which deviate from the requirements of the present invention have a low melting point and are exposed to an oven at 200 ° C for 500 hours continuously. The effect of heat resistance is insufficient, such as low retention of fiber strength.

A heat-resistant fiber obtained by melt-spinning a thermoplastic resin containing, as a main component, a block copolymer composed of 30% by weight of an aliphatic polyamide component and 70% by weight of a nylon 6-T component. A heat-resistant fiber, in which the amount of carboxyl end groups and the amount of amino end groups of the fibers are the same, which is a web that has deviated from the requirements of the present invention, is entangled by the nidle punch method while being laminated on the base fabric. The felt has a large heat-press fatigue property, and has low durability as a heat-resistant felt used in various industries, especially as a felt for papermaking, that is, physical and mechanical durability.

In the heat-resistant fiber and heat-resistant felt (Example 3) prepared by blending a phenolic antioxidant represented by hindered phenol (Example 3), the heat-resistant fiber and heat-resistant felt not blended (Example 1). ), The retention of fiber strength after 500 hours of continuous exposure in an oven at 200 ° C is even higher, and in particular the durability of the function as a felt for papermaking,
That is, the physical and mechanical durability is further enhanced.

The outermost layer of the web of the heat-resistant felt is directly exposed to high temperature heat and is subject to direct wear, so that the heat-resistant felt of the present invention in which the outermost layer of the web is made of heat-resistant fiber is particularly durable against wear. The efficiency can be enhanced efficiently.

Claims (6)

[Claims] 1. A thermoplastic resin containing an aromatic polyamide (hereinafter referred to as nylon 6-T) as a main component, which is polycondensed with hexamethylenediamine and terephthalic acid and has an aromatic ring in its main chain, is melt-spun. A heat resistant fiber comprising a part or all of a heat resistant fiber formed by and / or a part or all of a web formed on one side or both sides of the base cloth made of the heat resistant fiber. felt. 2. An aliphatic polyamide (hereinafter referred to as PA)
Consists of a part or all of heat-resistant fiber obtained by melt-spinning a thermoplastic resin whose main component is a block copolymer composed of 1 to 20% by weight of nylon and 99 to 80% by weight of nylon 6-T component. A heat-resistant felt, characterized in that a part or all of a web formed on one side or both sides of the formed base fabric and / or the base fabric is composed of the heat-resistant fiber. 3. A heat-resistant fiber obtained by melt-spinning a thermoplastic resin containing nylon 6-T as a main component, and a PA component of 1
To 20% by weight and a nylon 6-T component of 99 to 80% by weight, and a base fabric formed by mixing and weaving heat-resistant fibers obtained by melt-spinning a thermoplastic resin containing a block copolymer as a main component. /
Alternatively, a heat-resistant felt, characterized in that the heat-resistant fibers are mixed and used together to form part or all of a web formed on one side or both sides of a base fabric. 4. The heat resistant fiber has more carboxyl end groups than amino end groups and a difference of 5 to 30 meq / kg.
The heat-resistant felt according to claim 1 or 2, wherein the heat-resistant felt is within the range. 5. The heat-resistant felt according to claim 1, wherein a phenolic antioxidant represented by a hindered phenol is mixed with the thermoplastic resin. 6. The heat-resistant felt according to claim 1, wherein a part or all of the outermost layer of the heat-resistant felt is the heat-resistant fiber according to any one of claims 1 to 5.