JPH0259313A - Polyester molded matter and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a molded matter whose ratio between bending strength of an injection direction and that of a right angle direction to the injection direction does not exceed a specific value, by a method wherein copolyester of a specific composition is injection-molded under a specific condition. CONSTITUTION:When thermotropic liquid crystalline random copolyester where it is constituted mainly of a constituent unit as shown by formulas I-III, their mol ratios of the formulas I, III are equal to each other and falls within a range of 15/85-40/60, and its intrinsic viscosity is at least 0.5 is injection-molded, a molded product whose ratio between bending strength of an injection direction and that of a right angle direction to the injection direction does not exceed 6 can be obtained. Hereupon. Ar<1> shows trivalent aromatic group and Ar<2> and Ar<3> show bivalent aromatic group. However, an aromatic ring may have a substituent group. Then when a molding temperature ( deg.C), a fluid starting temperature ( deg.C) of the copolyester, a mold temperature ( deg.C) and a glass transition temperature ( deg.C) of the copolyester are made respectively Ts, Tf, Tk and Tg at the time of injection molding, it is necessary to perform injection molding under a state satisfying two formulas of S<=Tf+30, 70<=Tk<=Tg-10.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention is made of a phosphorus-containing thermodropink liquid crystalline copolyester, which has excellent heat resistance and flame retardancy.

The present invention also relates to a polyester molded product with reduced anisotropy and excellent impact strength, and a method for producing the same.

(Prior Art) Fully aromatic polyester has been well known as a heat-resistant polymer. However, most wholly aromatic polyesters are materials that are difficult to mold.

It has limited uses.

Furthermore, although wholly aromatic polyesters generally have excellent properties, they have extremely high melting points.

Moreover, since the melt viscosity is high, there is a problem that molding must be performed at high temperature and high pressure.

Therefore, interest has been focused on the development of thermotropic liquid crystalline polyesters with good melt moldability, and many proposals have been made.

The present inventors have also developed specific aromatic diol components, aromatic dicarboxylic acid components, and aromatic hydroxycarboxylic acid components as thermotropic liquid crystalline polyesters that have excellent heat resistance, tl flammability, etc., and good melt moldability. We previously proposed a copolyester made from
issue).

(Problem to be solved by the invention) However, since this copolyester has strong liquid crystallinity, the molded product obtained by injection molding it under normal conditions has large anisotropy, that is, the strength in the injection direction is Although very expensive,
The problem remained that the strength in the direction perpendicular to the injection direction was extremely small.

The technical problem of the present invention is to obtain an injection molded product with relaxed anisotropy from a thermotropic liquid crystalline copolyester having excellent heat resistance, flame retardancy, and melt moldability as described above. .

(Means for Solving the Problems) As a result of intensive research in order to solve the above problems, the present inventors have found that this object has been achieved by injection molding a copolyester with a specific composition under specific conditions. The present invention was achieved based on this discovery.

That is, the gist of the present invention is as follows.

(1) Mainly consists of structural units represented by the following structural formulas [1] to [3], and the molar ratio of each structural unit is [1] and [2].
] are substantially equal, and [1] and [3] are 15/85
-40/60 and has an intrinsic viscosity of 0.5 or more, the injection molded product is made of thermotropic liquid crystalline random copolyester, and has a bending strength in the injection direction and a bending strength in a direction perpendicular to the injection direction. A polyester molded article characterized in that the ratio is 6 or less.

Cost p O=P ■-0-Ar'-
0-10C-Ar2-Co-〇〇-Ar3-0- ■(Ar' is a trivalent aromatic group, Ar'' and Ar3 are divalent aromatic groups. However, the aromatic ring is (2) The thermotropic liquid crystalline copolyester described in (1) above is injection molded under conditions satisfying the following formulas [a] and [b]. 12. The method for producing a polyester molded article according to 11.

Ts≦Tf+30 of 70≦Tk≦Tg-10 ◎ [Ts is the molding temperature (°C), Tf is the flow start temperature of the copolyester (°C), Tk is the mold temperature (°C), and Tg is the glass transition temperature of the copolyester (°C). ] The copolyester in the present invention is a thermotropic liquid crystalline copolyester mainly consisting of a phosphorus-containing aromatic diol residue unit of formula (1), an aromatic dicarboxylic acid residue unit of formula (2), and an aromatic hydroxycarboxylic acid residue unit of formula (2). It is polyester.

Ar', Ar2 and Ar3 in formulas 1 to 2 are preferably benzene rings and naphthalene rings, and the aromatic rings in 2 to 2 are alkyl groups having 1 to 20 carbon atoms, alkoxy groups, and aryl groups having 6 to 20 carbon atoms. It may have a substituent such as a group, an allyloxy group or a halogen atom.

Specific examples of the phosphorus-containing aromatic diol forming the structural unit of formula (2) include compounds represented by the following formulas (al to (d+), and compounds of (al) are particularly preferred.

Specific examples of aromatic dicarboxylic acids forming the structural unit of formula (2) include terephthalic acid (TPA), isophthalic acid <I
PA), 4,4'-diphenyldicarboxylic acid, 2,6-
Examples include naphthalenedicarboxylic acid, 2,2-bis(4'-carboxyphenyl)propane, bis(4-carboxyphenyl)methane, and bis(4-carboxyphenyl)ether.

Particularly preferred aromatic dicarboxylic acids are TPA and IP
8, and the molar ratio of TPA and IP8 is 10010~
O/100° preferably 10010-50150. Optimally, it is best to use a ratio of 10010 to 70/30.

Specific examples of aromatic hydroxycarboxylic acids forming the structural unit 2〇 include 4-hydroxybenzoic acid, 4-
Hydroxy-3-chlorobenzoic acid 4-hydroxy-3-
Examples include phenylbenzoa, 2-hydroxy-6-naphthoic acid, 1-hydroxy-4-naphthoic acid, etc.
Particularly preferred is 4-hydroxybenzoic acid.

In the copolyester of the present invention, the ratio of the structural units (1) and (2) must be substantially equimolar; unless this condition is met, a copolyester with a high degree of polymerization cannot be obtained.

In addition, the ratio of the constituent units and ■ is 15/85 to 40
It is necessary to have a molar ratio of /60, preferably 2
A molar ratio of 0/80 to 30/70 is suitable. If the proportion of the constituent unit ■ is too small, the flow start temperature will become too high,
On the other hand, if the proportion of the structural unit (2) is too large, the anisotropy becomes too strong, which is not preferable.

Furthermore, polyesters may be copolymerized with components other than those mentioned above within a range that does not impair the properties of the polyester molded product of the present invention. Examples of such copolymerized components include resorcinol and hydroquinone.

4.4'-dihydroxydiphenyl, 2,2-bis(4
'-hydroxyphenyl)propane, bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)ether 1 ethylene glycol, diethylene glycol, 1,4-cyclohexane dimetatool, 1,4-cyclohexanediol, pentaerythritol, 1,4
-Cyclohexanedicarboxylic acid, adipic acid 8, trimellitic acid, and the like.

Heat resistance and various physical properties of polyester molded products.

In order to achieve both properties, the composition of the copolyester should be such that the flow start temperature is 330°C or lower, preferably 300°C or lower, the heat distortion temperature is 150°C or higher, preferably 155°C or higher, and optimally the flow start temperature is 150°C or higher, preferably 155°C or higher. At 240-280℃.

It is desirable to set the heat distortion temperature to 160 to 200°C.

The polyester used in the present invention needs to have an intrinsic viscosity [η] of 0.5 or more, preferably 1.
0-10.0. The optimum value is 2.0 to 6.0. If [η] is less than 0.5, various physical and mechanical properties including heat resistance will be poor, which is not preferable. However, if [η] is too large, the melt viscosity becomes too high and melt moldability is impaired, which is undesirable.
Desirably 0 or less.

The copolyester in the present invention can be produced by a conventional method for producing wholly aromatic polyesters.

For example, (i) substantially equimolar amounts of phosphorus-containing aromatic diol, aromatic dicarboxylic acid, and the amount of hydroxyl groups or more, preferably 1.05 to 1.25 times equivalent of lower fatty acid acid anhydride (e.g. (acetic anhydride) or (ii) substantially equimolar lower fatty acid ester of phosphorus-containing aromatic diol and aromatic dicarboxylic acid (preferably 0.05 to 0.25 equivalents of the amount of hydroxyl residue of lower fatty acid) (along with anhydride) is charged into a reactor and subjected to an 8-polycondensation reaction.

To prepare the copolyesters of the present invention, two typical methods are used.

A polycondensation catalyst is used, and the single polycondensation catalyst is one selected from various metal compounds and organic sulfonic acid compounds.
More than one type of compound can be used.

As the metal compound, compounds such as antimony, titanium, germanium, tin, zinc, aluminum, magnesium, calcium, manganese, potassium, sodium, or cobalt are used.

Examples of organic sulfonic acid compounds include sulfosalicylic acid, 0
Compounds such as -sulfobenzoic anhydride are used, and dimethyltin maleate and 0-sulfobenzoic anhydride are particularly preferably used.

The amount of the catalyst added is usually 0.1X10-' to 100X10-' mole, preferably 0.5X10-' to 50X10-' mole, optimally 1x10-4 to 1X10-' mole, per mole of the polyester structural unit. 10XIO'-' moles are suitable.

The polycondensation reaction is first carried out at a temperature of about 150°C under normal pressure.
After carrying out the acid exchange reaction or esterification reaction for about 2 hours, the temperature is sequentially raised to about 270°C, and if necessary, the pressure is reduced to distill acetic acid while the reaction is carried out.
The reaction is carried out at a temperature of 1 Torr or less under reduced pressure for several tens of minutes to several hours.

Note that in some cases, the polycondensate solidifies during the single polycondensation reaction and becomes a solid state, and in other cases, it can be polycondensed while remaining in a molten state.

The polyester molded product of the present invention can be obtained by injection molding such a copolyester, but during injection molding, it is necessary to satisfy the conditions of the above formulas ① and ＠.

That is, the molding temperature Ts is (Tf+303''c or less).

Preferably (Tf+203℃ or less, mold temperature Tk 70
°C ~ (Tg-10) °C, preferably 100 °C ~ (T
g-30]℃. On the other hand, if Ts is too high or Tk is too low, the anisotropy of the molded product will not be sufficiently relaxed.

If the mold temperature Tk is too high, the molded product may be deformed, which is not preferable.

When injection molding is carried out under such conditions, a molded product is obtained in which the ratio of bending strength (MD) in the injection direction to bending strength (TD) in a direction perpendicular to the injection direction is c or less, usually 5 or less.

In addition, the molded product thus obtained has excellent impact strength, with an Izod impact strength of 5 kgf-ctn.
/cm or more 2 Normally 8 kgf-cm/cm or more.

The molded article of the present invention has relaxed anisotropy.

It shows sufficiently high impact strength without containing reinforcing materials or fillers, but by containing reinforcing materials or fillers,
Heat resistance and impact strength can be further improved.

Examples of reinforcing materials include glass fibers, carbon fibers, whiskers, ceramic whiskers such as A12C)r+SiC, graphite, and metallic whiskers such as chromium, copper, iron, and nickel.

Fillers include metal powders such as aluminum, copper, and iron; silicic acids such as mica, clay, talc, and asbestos; carbides such as graphite and carbon black; and metal oxides such as alumina, antimony oxide, and zirconium carbide. , and the same carbide.

If reinforcing materials or fillers are included, what are their amounts?

Usually 5 to 50% by weight, preferably 20 to 40% by weight is appropriate.

(Example) Next, the present invention will be explained in more detail with reference to Examples.

Incidentally, the method of measuring the characteristic value is as follows.

It was determined from the solution viscosity measured at 20°C using a mixed solvent of equal weights of phenol and tetrachloroethane.

ゞ! @ Soup ・Temperature (Tf) Using a flow tester (CFT 500 model manufactured by Shimadzu Corporation), the load was 100 kg/cnt and the nozzle diameter was 0.
The temperature was increased from 200°C at a rate of 10°C/min under the condition of 5mm.

It was determined as the temperature at which the polymer begins to flow out.

Glass cloud Speech (T) Differential scanning calorimeter (PerkinElmer DSC-2 model)
The measurement was performed using a temperature increasing rate of 20° C./min.

Limiting oxygen index (LOI) according to flammability JIS K7201 standard
was determined for a sample with a thickness of 1/163 inch.

Bending Agency (MD and TD) Injection molded 12.7cm square flat plate (thickness 1/8:')
A test piece cut to a width of 1.5 cm in the injection direction and a test piece cut to a width of 1.5 cm in a direction perpendicular to the injection direction were prepared and measured according to the JIS K7203 standard.

Izot'-jfp (IZ) 1/8 thickness according to ASTM D256! Measurements were made with a hole and a notch. (Unit: kgf・am/cm)
Measured under heavy load in accordance with ASTM 0648.

In addition, the thermotropic liquid crystal is Le with a hot stage.
Confirmed using an itz polarization microscope.

Example 1 In a polycondensation reactor, phosphorus-containing aromatic diol (PPQ) of the formula (a), TPA, and 4-hydroxybenzoic acid (
411BA) and acetic anhydride in a molar ratio of 30:30.
: 70 : 145, dimethyltin maleate was added as a catalyst in an amount of 4 x 10-' mol per 1 mol of polyester repeating unit, and under a nitrogen atmosphere,
The reaction was carried out at normal pressure and 150° C. for 2 hours while being mixed. This reactant further.

The reaction was carried out at 240°C for 2 hours and at 280°C for 2 hours under normal pressure.

Next, the reaction was carried out by gradually increasing the temperature under a reduced pressure of 0.1 torr, and finally the temperature was raised to 320°C.
Melt polymerization was carried out at that temperature for 3 hours.

The obtained copolyester was molded at the temperature Ts shown in Table 1.
and injection molding at a mold temperature Tk.

Examples 2 to 6 In place of PPQ, 4++BA and TPA in Example 1, PPQ and 4HB at the charged molar ratios shown in Table 1 were used.
A. A polyester molded article was produced in the same manner as in Example 1 using TPA and IP8.

Examples 7 to 9 In Example 1, the formula (bl~(d
) A polyester molded article was produced in the same manner as in Example 1 using the phosphorus-containing aromatic diol.

Example 10 PPQ, R3 (resorcinol), 4 in the polycondensation reactor
H.B.A.

TPA, IP8 and acetic anhydride in a molar ratio of 20:1
The ratio of 0:70:27:3:145 was charged, and dimethyltin maleate was added as a catalyst in an amount of 4 x 10-' mol per 1 mol of polyester repeating unit.
The reaction was carried out under a nitrogen atmosphere at normal pressure and 150° C. for 2 hours with mixing. This reaction product was further heated at 240°C under normal pressure.
The mixture was reacted for 2 hours at 280° C. under a reduced pressure of 50 torr. Next.

The reaction was carried out by gradually increasing the temperature under a reduced pressure of 0.1 torr, and finally the temperature was raised to 310° C., and melt polymerization was carried out at that temperature for 5 hours.

The obtained copolyester was molded at the temperature Ts shown in Table 1.
and injection molding at a mold temperature Tk.

Example 11 PP port and HQ (hydroquinone) in the polycondensation reactor.

411BA, TPA, IP8, and acetic anhydride were charged in a molar ratio of 20:10:10224:6:1/15, and dimethyltin maleate was added as a catalyst at a rate of 4X per mole of polyester repeating unit. 10
-' mole was added, and the mixture was reacted under a nitrogen atmosphere at normal pressure at 150° C. for 2 hours with mixing.

This reaction product was further heated at 250° C. for 2 hours under normal pressure.

The reaction was carried out at 260° C. for 2 hours under a reduced pressure of 50 torr. Next, the reaction was carried out by gradually increasing the temperature under a reduced pressure of 0.1 Torr, and finally the temperature was raised to 320° C. and melt polymerization was carried out at that temperature for 4 hours.

The molding temperature T of the obtained copolyester shown in Table 1
Injection molding was performed at s and mold temperature Tk.

Comparative Examples 1 to 4 Copolyesters were produced in the same manner as in Example 1 except that the molar ratio of PP (1,4118^ and TPA) was changed as shown in Table 1. A polyester molded product was obtained by injection molding under the following conditions.

Table 1 shows the characteristic values of the copolyesters and molded products obtained in the above Examples and Comparative Examples.

The copolyesters in each example were all thermotropic liquid crystalline copolyesters with good color tone.

(Effects of the Invention) According to the present invention, it is possible to obtain a polyester molded product made of a phosphorus-containing thermotropic liquid crystalline copolyester and having excellent heat resistance and flame retardancy, moderated anisotropy, and excellent impact strength. Can be done.

1. The polyester molded product of the present invention has particularly high heat resistance,
ii [Extremely useful as a molded product used in applications requiring high flammability and strength.

Patent applicant: Nihon Ester Co., Ltd.

Claims (2)

[Claims] (1) Mainly consists of structural units represented by the following structural formulas [1] to [3], and the molar ratio of each structural unit is [1] and [2].
] are substantially equal, and [1] and [3] are 15/85
- 40/60, and the ratio of the bending strength in the injection direction to the bending strength in the direction perpendicular to the injection direction is an injection molded product made of thermotropic liquid crystal random copolyester having an intrinsic viscosity of 0.5 or more 6 or less. ▲There are mathematical formulas, chemical formulas, tables, etc.▼[1] -OC-Ar^2-CO-[2] -OC-Ar^3-O-[3] (Ar^1 is a trivalent aromatic group, Ar ^2 and Ar^3 represent a divalent aromatic group. However, the aromatic ring may have a substituent.) (2) The method for producing a polyester molded article according to claim 1, characterized in that the thermotropic liquid crystalline copolyester according to claim 1 is injection molded under conditions that satisfy the following formulas [a] and [b]. Ts≦Tf+30 [A] 70≦Tk≦Tg-10 [B] [Ts is the molding temperature (℃), Tf is the copolyester flow start temperature (℃), Tk is the mold temperature (℃), Tg is the copolyester The glass transition temperature (°C) of ]