JP7169869B2 - Wholly aromatic polyesteramide, polyesteramide resin composition, and polyesteramide molded article - Google Patents

Description

TECHNICAL FIELD The present invention relates to a wholly aromatic polyester amide, a resin composition containing the wholly aromatic polyester amide, and a molded article thereof.

Liquid crystalline polymers are widely used as high-performance engineering plastics because they have a good balance of fluidity, mechanical strength, heat resistance, chemical resistance, electrical properties, and the like. As liquid crystalline polymers, for example, wholly aromatic polyesters obtained by copolymerizing 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and optionally other monomer components are known. In addition, a wholly aromatic polyesteramide is known in which an amino group is introduced into a wholly aromatic polyester. Since hydrogen bonds are formed between polymer chains, wholly aromatic polyester amides tend to be superior to wholly aromatic polyesters in performance such as mechanical strength, heat resistance, moldability, and elastic modulus.

Of the wholly aromatic polyester amides, those using three specific raw material monomers include, for example, copolymerization of 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and 3-aminobenzoic acid. What is obtained is known (Patent Document 1).

Japanese Patent Application Laid-Open No. 2004-339462

However, in the wholly aromatic polyester amide represented by Patent Document 1, when the wholly aromatic polyester amide obtained by copolymerizing the above-mentioned three specific types in combination is used, the tensile modulus of elasticity is not sufficient.

By increasing the amount of a monomer containing an amino group (for example, 3-aminobenzoic acid or 4-aminobenzoic acid), the proportion of amide bonds is increased, and the proportion of hydrogen bonds formed by the hydrogen atoms of amide bonds is reduced. There is a method of improving the tensile modulus by increasing the size.

However, if the amount of the amino group-containing monomer increases, the polymer may harden and it may be difficult to discharge, so there is a problem that the ratio of hydrogen bonds with strong bonding strength cannot be easily increased.

The present invention has been made in view of the conventional problems described above, and an object of the present invention is to provide a wholly aromatic polyesteramide having a high tensile modulus.

As a result of intensive research to achieve the above object, the present inventors have found that by using multiple types of monomers containing amino groups and increasing the proportion of amide bonds, the proportion of hydrogen bonds with strong bonding strength increases, It has been found that a rigid polymer can be obtained and is effective for achieving the above object.

One aspect of the present invention for achieving the above object is as follows.

(1) Including structural units represented by the following general formulas (I), (II) and (III), the structural units represented by the general formula (I) being 40 to 70 mol% of all structural units, The total of structural units represented by general formula (II) and general formula (III) is 30 to 60 mol%, and the total of structural units represented by general formulas (I), (II), and (III) is 100 mol %, and the ratio of the structural unit represented by general formula (II) to the structural unit represented by general formula (III) is 0.5 to 2.

(2) The wholly aromatic polyesteramide according to (1) above, which has a tensile modulus of 40 cN/dtex or more.

(3) A polyesteramide resin composition containing the wholly aromatic polyesteramide described in (1) or (2) above.

(4) A polyesteramide molded article formed from the wholly aromatic polyesteramide described in (1) or (2) above or the polyesteramide resin composition described in (3) above.

(5) The polyesteramide molded article according to (4) above, wherein the molded article is a fiber.

According to the present invention, a wholly aromatic polyesteramide having a high elastic modulus can be provided.

<Whole aromatic polyester amide>
Raw materials necessary for forming the wholly aromatic polyesteramide constituting one aspect of the present embodiment are described below.

One of the raw materials used in one aspect of the present embodiment contains a structural unit represented by the following general formula (I). Another raw material used in one aspect of the present embodiment contains a structural unit represented by the following general formula (II). Furthermore, another one of the raw materials used in one aspect of the present embodiment contains a structural unit represented by the following general formula (III).

Monomers from which structural units represented by general formula (I) are derived include, for example, 6-hydroxy-2-naphthoic acid (hereinafter also referred to as “HNA”).

The monomer from which the structural unit represented by general formula (II) is derived is, for example, 4-aminobenzoic acid (hereinafter also referred to as "pABA") or 4-acetamidobenzoic acid (hereinafter also referred to as "pAABA"). ), etc.
Since the reaction is milder when using pAABA than when using pABA, pAABA is used in the examples described later.

The monomer from which the structural unit represented by the general formula (III) is derived is, for example, 3-aminobenzoic acid (hereinafter also referred to as "mABA") or 3-acetamidobenzoic acid (hereinafter also referred to as "mAABA"). ), etc.
Since the reaction is milder when using mAABA than when using mABA, mAABA is used in the examples described later.

In the wholly aromatic polyesteramide of one aspect of the present embodiment obtained by polycondensation of raw materials containing structural units represented by general formulas (I), (II), and (III), the polymerization ratio of each structural unit is important for developing an excellent tensile modulus, which is the object of one aspect of the present embodiment.

Specifically, the structural unit represented by general formula (I) is 40 to 70 mol% with respect to all structural units, and the total number of structural units represented by general formula (II) and general formula (III) is 30 to 60 mol%, the total of the structural units represented by general formulas (I), (II), and (III) is 100 mol%, relative to the structural units represented by general formula (III) The ratio of structural units represented by general formula (II) is 0.5-2. The tensile elastic modulus of the wholly aromatic polyester amide of one aspect of the present embodiment is preferably 40 cN/dtex or more, more preferably 45 cN/dtex or more, and even more preferably 50 cN/dtex or more.

The wholly aromatic polyesteramide of the present embodiment contains 40 to 70 mol % of structural units represented by general formula (I) with respect to all structural units. When the content of the structural unit represented by the general formula (I) is within the above range, a rapid increase in torque due to thickening during polymerization is less likely to occur, and stable polymerization can be achieved, which is preferable. The content of the structural unit represented by general formula (I) is preferably 45 to 70 mol%, more preferably 45 to 65 mol%, still more preferably 50 to 65 mol%, particularly preferably 50 to 60 mol%. is.

In this embodiment, the total content of structural units represented by general formulas (II) and (III) is 30 to 60 mol %. When the total content is within the above range, hydrogen bonds are appropriately formed, so that it is possible to obtain a wholly aromatic polyester amide having a high tensile modulus while ensuring manufacturability. The total content is preferably 30 to 55 mol%, more preferably 35 to 55 mol%, still more preferably 35 to 50 mol%, particularly preferably 40 to 50 mol%.

Structural units containing amino groups with respect to all structural units of a wholly aromatic polyesteramide using a raw material containing a structural unit represented by general formula (II) and a raw material containing a structural unit represented by general formula (III) is preferably increased. As described above, the use of two raw materials containing a structural unit containing an amino group reduces the molecular cohesive force, resulting in a softening point depression, and only one raw material containing a structural unit containing an amino group is the same. Thickening of the raw material can be suppressed as compared with the case of using a large amount. For this reason, it is possible to prevent the polymer from solidifying and being unable to be discharged, thereby making it impossible to produce the wholly aromatic polyesteramide.

In this embodiment, the ratio of the structural unit represented by general formula (II) to the structural unit represented by general formula (III) is 0.5-2. When the ratio is within the above range, thickening of the raw material is suppressed, and a wholly aromatic polyesteramide can be obtained. The ratio is preferably 0.5-1.5, more preferably 0.75-1.5.

It is preferable to carry out polycondensation using only the structural units represented by general formulas (I), (II) and (III). When polycondensation is performed using only the above three components, the homogeneity of the raw materials can be maintained, and the lowering of the melting point can be suppressed.

As described above, a wholly aromatic polyesteramide having a high tensile modulus can be produced by setting the polymerization ratio of each structural unit within the range described above.

Next, properties of the wholly aromatic polyesteramide will be described. The wholly aromatic polyester amide of the present embodiment exhibits optical anisotropy when melted. Exhibiting optical anisotropy when melted means that the wholly aromatic polyesteramide of the present embodiment is a liquid crystalline polymer.

In the present embodiment, the fact that the wholly aromatic polyester amide is a liquid crystalline polymer is an essential factor for the wholly aromatic polyester amide to have both thermal stability and easy processability. Wholly aromatic polyester amides composed of structural units represented by the general formulas (I), (II), and (III) form an anisotropic melt phase depending on the constituent components and the sequence distribution in the polymer. The polymer of this embodiment is limited to a wholly aromatic polyester amide that exhibits optical anisotropy when melted, although there are some that do not.

The properties of melt anisotropy can be confirmed by a conventional polarization inspection method using crossed polarizers. More specifically, melting anisotropy can be confirmed by using an Olympus polarizing microscope, melting a sample placed on a Linkcom hot stage, and observing it under a nitrogen atmosphere at a magnification of 150 times. Liquid crystalline polymers are optically anisotropic and transmit light when interposed between crossed polarizers. If the sample is optically anisotropic, polarized light will be transmitted even in the quiescent molten state, for example.

Since a nematic liquid crystalline polymer significantly lowers in viscosity above its melting point, exhibiting liquid crystallinity at a temperature equal to or above the melting point is generally an index of workability. From the viewpoint of heat resistance, the melting point is preferably as high as possible, but considering the thermal deterioration of the polymer during melt processing, the heating capacity of the molding machine, etc., 380° C. or less is a preferable standard. The melting point is preferably 260 to 370°C, more preferably 270 to 370°C, still more preferably 280 to 370°C.

Next, a method for producing the wholly aromatic polyesteramide of the present embodiment will be described. The wholly aromatic polyesteramide of the present embodiment is polymerized using a direct polymerization method, a transesterification method, or the like. In the polymerization, a melt polymerization method, a solution polymerization method, a slurry polymerization method, a solid phase polymerization method, or a combination of two or more thereof is used. is preferably used.

In this embodiment, in the polymerization, an acylating agent for the polymerization monomer or a terminal-activated monomer as an acid chloride derivative can be used. Acylating agents include fatty acid anhydrides such as acetic anhydride.

Various catalysts can be used in these polymerizations, and representative ones include potassium acetate, magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, antimony trioxide, tris ,4-pentanedionato)cobalt (III), and organic compound catalysts such as N-methylimidazole and 4-dimethylaminopyridine. The amount of catalyst used is generally about 0.001 to 1% by weight, preferably about 0.003 to 0.2% by weight, based on the total weight of the monomers.

[Polyesteramide resin composition]
The wholly aromatic polyester amide of the present embodiment can be blended with various fibrous, powdery, plate-like inorganic and organic fillers depending on the purpose of use to form a polyester amide resin composition.

Examples of inorganic fillers to be blended in the polyesteramide resin composition of the present embodiment include fibrous, granular, and plate-like fillers.

Examples of fibrous inorganic fillers include glass fiber, silica fiber, silica/alumina fiber, alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, silicate fiber such as wollastonite, Inorganic fibrous materials such as magnesium sulfate fibers, aluminum borate fibers, and fibrous materials of metals such as stainless steel, aluminum, titanium, copper, and brass can also be used. A particularly representative fibrous filler is glass fiber.

Examples of powdery inorganic fillers include carbon black, graphite, silica, quartz powder, glass beads, milled glass fiber, glass balloons, glass powder, calcium silicate, aluminum silicate, kaolin, clay, diatomaceous earth, and wollastonite. silicates such as night, iron oxide, titanium oxide, zinc oxide, antimony trioxide, metal oxides such as alumina, metal carbonates such as calcium carbonate and magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate Salt, other ferrite, silicon carbide, silicon nitride, boron nitride, various metal powders, and the like.

Examples of plate-like inorganic fillers include mica, glass flakes, talc, and various metal foils.

Examples of organic fillers blended in the polyesteramide resin composition of the present embodiment include heat-resistant and high-strength synthetic fibers such as aromatic polyester fibers, liquid crystalline polymer fibers, aromatic polyamide fibers, and polyimide fibers. .

These inorganic and organic fillers can be used alone or in combination of two or more. Combined use of a fibrous inorganic filler and a granular or plate-like inorganic filler is a preferable combination for achieving mechanical strength, dimensional accuracy, electrical properties, and the like. Particularly preferably, glass fiber is used as the fibrous filler, and mica and talc are used as the plate-like filler. Department. By combining the glass fiber with mica or talc, the polyesteramide resin composition has a particularly remarkable improvement in heat distortion temperature, mechanical properties, and the like.

When using these fillers, a sizing agent or a surface treatment agent can be used if necessary.

As described above, the polyesteramide resin composition of the present embodiment contains, as essential components, the wholly aromatic polyesteramide of the present embodiment and, if necessary, an inorganic or organic filler. Other components may be included as long as they are not included. Here, the other component may be any component, and examples thereof include additives such as other resins, antioxidants, stabilizers, pigments, and crystal nucleating agents.

Moreover, the method for producing the polyesteramide resin composition of the present embodiment is not particularly limited, and the polyesteramide resin composition can be prepared by a conventionally known method.

[Polyesteramide molding]
The polyesteramide molded article of the present embodiment is obtained by molding the wholly aromatic polyesteramide or polyesteramide resin composition of the present embodiment. The molding method is not particularly limited, and a general molding method can be adopted. Examples of general molding methods include injection molding, extrusion molding, compression molding, blow molding, vacuum molding, foam molding, rotational molding, gas injection molding, and inflation molding.

The polyesteramide molded article of the present embodiment has a high tensile modulus because it is obtained by molding the above-described wholly aromatic polyesteramide or polyesteramide resin composition of the present embodiment.

In addition, the wholly aromatic polyester amide and polyester amide resin composition of the present embodiment are excellent in moldability and can be processed into various three-dimensional molded articles, fibers, films, and the like.

Preferable applications of the polyesteramide molded article of the present embodiment having the properties as described above include connectors, CPU sockets, relay switch parts, bobbins, actuators, noise reduction filter cases, electronic circuit boards or heat fixing rolls for OA equipment, Examples include ropes, cords, protective clothing, and the like.

EXAMPLES The present embodiment will be described in more detail below with reference to examples, but the present embodiment is not limited to the following examples.

A wholly aromatic polyesteramide was prepared by the method described below.

(Example 1)
A polymerization vessel equipped with a stirrer, a reflux column, a monomer inlet, a nitrogen inlet, and a pressure reduction/effluent line was charged with the following raw material monomers, a fatty acid metal salt catalyst, and an acylating agent to initiate nitrogen substitution. The following (I) to (III) are monomers from which the structural units of general formulas (I) to (III) are derived, respectively.
(material)
(I) 6-hydroxy-2-naphthoic acid (HNA): 97.6 g (50 mol%)
(II) 4-acetamidobenzoic acid (pAABA): 46.5 g (25 mol%)
(III) 3-acetamidobenzoic acid (mAABA): 46.5 g (25 mol%)
Potassium acetate (fatty acid metal salt catalyst): 11 mg
Acetic anhydride (acylating agent): 54 g (1.02 times the hydroxyl equivalent of HNA)
After charging the raw materials, the temperature of the reaction system was raised to 140° C., and the reaction was carried out at 140° C. for 1 hour. After that, the temperature was further raised to 330° C. over 3.3 hours, and the pressure was reduced to 10 Torr (that is, 1330 Pa) over 15 minutes to distill off acetic acid, excess acetic anhydride, and other low-boiling components. condensation was performed.

<Evaluation>
In the above-described polycondensation, after the stirring torque reached a predetermined value, nitrogen was introduced to change from a reduced pressure state to a normal pressure state to a pressurized state, and whether the polymer was discharged from the bottom of the polymerization vessel was evaluated. Table 1 shows the evaluation results. Moreover, when discharging, it was pelletized to obtain resin pellets.

[Tensile modulus]
The obtained resin pellets were drawn at 300° C. using a capillograph (CHAPILOGRAPH 1D, manufactured by Toyo Seiki Co., Ltd.) equipped with a melt tension measuring device to obtain fibers drawn 45 times. The obtained fiber was subjected to a tensile test using a tensile tester (TENSILON RTM-100, manufactured by Orientec Co., Ltd.) to calculate the tensile modulus. Table 1 shows the evaluation results.

(Examples 2, 3, Comparative Examples 1-5, 7-9)
Polycondensation was carried out in the same manner as in Example 1, except that the types of raw material monomers and the charging ratio (mol %) were as shown in Table 1. Then, the same evaluation as in Example 1 was performed. Table 1 shows the evaluation results.

(Comparative Example 6)
A polymerization vessel equipped with a stirrer, a reflux column, a monomer inlet, a nitrogen inlet, and a pressure reduction/effluent line was charged with the following raw material monomers, a fatty acid metal salt catalyst, and an acylating agent to initiate nitrogen substitution.
(material)
(I) 6-hydroxy-2-naphthoic acid (HNA): 113.1 g (60 mol%)
4-hydroxybenzoic acid (pHBA): 35.9 g (20 mol%)
3-hydroxybenzoic acid (mHBA): 35.9 g (20 mol%)
Potassium acetate (fatty acid metal salt catalyst): 11 mg
Acetic anhydride (acylating agent): 63 g (1.02 times the total hydroxyl equivalent of HNA, pHBA, and mHBA)
After charging the raw materials, the temperature of the reaction system was raised to 140° C., and the reaction was carried out at 140° C. for 1 hour. After that, the temperature was further raised to 350° C. over 3.7 hours, and the pressure was reduced to 10 Torr (that is, 1330 Pa) over 15 minutes to distill off acetic acid, excess acetic anhydride, and other low-boiling components. condensation was performed. Then, the same evaluation as in Example 1 was performed. Table 1 shows the evaluation results.

(Comparative Example 10)
A polymerization vessel equipped with a stirrer, a reflux column, a monomer inlet, a nitrogen inlet, and a pressure reduction/effluent line was charged with the following raw material monomers, a fatty acid metal salt catalyst, and an acylating agent to initiate nitrogen substitution.
(material)
(I) 6-hydroxy-2-naphthoic acid (HNA): 53.4 g (25 mol%)
(II) 4-acetamidobenzoic acid (pAABA): 101.7 g (50 mol%)
4-hydroxybenzoic acid (pHBA): 39.2 g (25 mol%)
Potassium acetate (fatty acid metal salt catalyst): 11 mg
Acetic anhydride (acylating agent): 59 g (1.02 times the total hydroxyl equivalent of HNA and pHBA)
After charging the raw materials, the temperature of the reaction system was raised to 140° C., and the reaction was carried out at 140° C. for 1 hour. After that, the temperature was further raised to 350° C. over 43.7 hours, and the pressure was reduced to 10 Torr (that is, 1330 Pa) over 15 minutes to distill off acetic acid, excess acetic anhydride, and other low-boiling components. condensation was performed. Then, the same evaluation as in Example 1 was performed. Table 1 shows the evaluation results.

In the table, "dischargeability" indicates whether or not the polymer is discharged from the polymerization vessel by ◯ (dischargeable) or x (dischargeable).

From Table 1, it can be seen that the polymer is discharged in all of Examples 1, 2, 3 and Comparative Example 6, but is not discharged in all of the other Comparative Examples because the polymer is solidified. In addition, it can be seen that Examples 1, 2 and 3, in which raw material monomers containing pAABA and mAABA are charged, have high tensile elastic modulus of the polymer and excellent tensile elastic modulus. Moreover, in Comparative Example 6, since the raw material monomer does not contain an amino group, it is considered that an improvement in the tensile elastic modulus due to hydrogen bonding could not be confirmed.

The tensile modulus tends to increase as the proportion of the amide content increases. In addition, it can be seen that there is an appropriate range for the amount of amide, and that the polymer cannot be produced without this range.

Claims (5)

Including structural units represented by the following general formulas (I), (II) and (III), the structural units represented by the general formula (I) are 40 to 70 mol% of the total structural units, and the general formula ( II) and the total amount of structural units represented by general formula (III) is 30 to 60 mol%, and the total amount of structural units represented by general formulas (I), (II), and (III) is 100 mol. % and the ratio of the structural unit represented by general formula (II) to the structural unit represented by general formula (III) is 0.5-2.

2. The wholly aromatic polyesteramide according to claim 1, which has a tensile modulus of 40 cN/dtex or more. A polyesteramide resin composition comprising the wholly aromatic polyesteramide according to claim 1 or 2. A polyesteramide molded article formed from the wholly aromatic polyesteramide according to claim 1 or 2 or the polyesteramide resin composition according to claim 3. 5. The polyesteramide molded article according to claim 4, wherein the molded article is a fiber.