JPH04283230A - Copolyester and its composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is capable of melt polymerization,
A copolymerized polyester with improved flowability that has excellent melt flowability and moldability, and can provide molded products with excellent heat resistance, rigidity, and mechanical properties such as impact resistance by ordinary molding methods. and its composition.

0002

[Background Art] In recent years, demands for higher performance plastics have been increasing, and many polymers with various new performances have been developed. Among them, optically anisotropic liquid crystal polymers have excellent mechanical properties. (JP-A-51-8395, JP-A-49-72393).

0003

As the above-mentioned liquid crystal polymer, for example, a liquid crystal polymer prepared by copolymerizing polyethylene terephthalate with p-hydroxybenzoic acid is known (Japanese Patent Application Laid-open No. 72393/1983). However, this polymer has drawbacks such as insufficient heat resistance and poor mechanical properties, and it has been found that injection molded products that satisfy both characteristics cannot be obtained from this polymer. Moreover, to improve heat resistance, the amount of p-hydroxybenzoic acid is 80%
It was also found that solid phase polymerization is necessary because solidification occurs during polymerization.

On the other hand, as a means for improving the fluidity of such a polymer, improving melt moldability, and further improving mechanical properties, there is a method as described in, for example, Japanese Patent Application Laid-Open No. 51-8395. A method of copolymerizing polyethylene terephthalate with p-acyloxybenzoic acid, aromatic dicarboxylic acid, and aromatic diol has been proposed, but although the mechanical properties of the injection molded product obtained by this method are improved, the heat resistance is poor. was found to be insufficient. On the other hand, as stated in Japanese Patent Publication No. 47-47870,
- Injection molded products made of wholly aromatic polyester made by copolymerizing hydroxybenzoic acid with 4,4'-dihydroxybiphenyl and terephthalic acid have good heat resistance, but have a softening temperature of 4.
It was found that melt polymerization was difficult because the temperature was 00°C or higher, and the mechanical properties were not fully satisfactory.

Furthermore, as electrical and electronic components become more densely packaged, materials with soldering heat resistance and thin-wall moldability (fluidity) are required, but in terms of the balance of these, materials are not suitable for the liquid crystal polymers mentioned above. It turns out that this is not always sufficient.

Therefore, the present invention solves the above problems, and can be obtained only by melt polymerization, has excellent melt fluidity and moldability, and has excellent heat resistance, rigidity, strength, and impact resistance by ordinary molding methods. The object of the present invention is to obtain a copolymerized polyester with improved fluidity that can provide molded articles having mechanical properties represented by physical properties.

[0007]

[Means for Solving the Problems] The present inventors have made extensive studies to achieve the above-mentioned problems, and as a result, have arrived at the present invention.

That is, the present invention provides: 1) the following structural unit (
I) to (IV), and the structural unit [(I)+(II)
] is [(I)+(II)+(III)]80-99
Mol%, structural unit (III) is [(I)+(II)+
(III)], and the structural unit (I
)/(II) molar ratio is 75/25 to 95/5, and (
The molar ratio of II)/(III) is 90/10 to 40/6
0, a melting point (Tm, °C) satisfies formula (1), and a copolymerized polyester having melt anisotropy whose logarithmic viscosity is 3.0 to 10.0 dl/g,

[0009]

[Case 2]

-15<Tm+7.70x-374.4<15
...(1) (However, x in formula (1) is the structural unit (II
The ratio (mol %) of I) to [(I)+(II)+(III)] is shown. ) 2) Temperature of melting point (Tm) + 10°C, shear rate 1000s
-1) The copolymerized polyester according to item 1) having a melt viscosity of 100 to 2000 poise as measured in 3) The copolymerized polyester according to item 1), which is produced by polymerizing at a temperature of melting point (Tm) + 30°C or lower. Polyester, 4) A copolymerized polyester composition obtained by adding a filler to the copolymerized polyester described in item 1), and 5) Deflection temperature under load (HDT, °C, 18.6 kgf/c
The present invention provides a copolyester composition according to item 4), in which m2) satisfies the following formula (2).

Tm-HDT<80°C...(2) The above structural unit (I) is a structural unit of polyester produced from p-hydroxybenzoic acid, and the structural unit (II) is produced from 4,4'-dihydroxybiphenyl. The structural unit (III) is a structural unit produced from 2,6-dihydroxynaphthalene, and the structural unit (IV) is a structural unit produced from terephthalic acid.

On the other hand, among the above structural units (I) to (IV), the structural unit [(I)+(II)] is the structural unit [(I)+
(II) + (III)] is 80 to 99 mol%,
Preferably it is 88 to 98 mol%.

Further, the structural unit (III) is the structural unit [(
I)+(II)+(III)] from 20 to 1 mol%, preferably from 12 to 2 mol%. Structural unit [(I
)+(II)] is the structural unit [(I)+(II)+(II
If it exceeds 99 mol %, melt fluidity decreases and solidification occurs during polymerization, or moldability is impaired. If it is less than 80 mol%, heat resistance will be poor, and either case is not preferred. Also, the molar ratio of structural units (I)/(II) is 7
5/25 to 95/5, preferably 80/20 to 9
2/8, more preferably 80/20 to 90/10
It is. If it is less than 75/25 or greater than 95/5, the heat resistance will be poor or the fluidity will be poor, making it impossible to achieve the object of the present invention.

[0014] Furthermore, the molar ratio of structural units (II)/(III) is one of the important points in the present invention, and its range is from 90/10 to 40/60, and from 85/15 to 45.
/55 is preferred. If larger than 90/10 or 40/
If it is less than 60, the above formula (1) is not satisfied and the fluidity becomes poor, which is not preferable.

Further, the structural unit (IV) is substantially equimolar to the structural unit [(II)+(III)].

The method for producing the copolyester of the present invention is preferably a melt polymerization method in view of the randomness of the polymer, and a bulk polymerization method in which part or all of the polymer is in a solid polydisperse state is not preferred. Further, the polymer thus obtained may be subjected to solid phase polymerization in combination.

A particularly preferred production method is a method in which p-hydroxybenzoic acid, 4,4'-dihydroxybiphenyl is reacted with acetic anhydride, 2,6-diacetoxynaphthalene, and terephthalic acid, and then acetic acid depolymerization is performed in the molten state. can be mentioned.

Although this polycondensation reaction proceeds without a catalyst,
It is sometimes preferable to add metal compounds such as stannous acetate, tetrabutyl titanate, sodium and potassium acetates, antimony trioxide, magnesium metal, and the like.

Furthermore, when producing the copolymerized polyester of the present invention by the melt polymerization method, the melting point (Tm) +3
Preferably, the polymerization is carried out at a temperature below 0°C. It goes without saying that when solid phase polymerization is further used, it is carried out at a temperature below the melting point (Tm).

[0020] Maximum polymerization temperature is melting point (Tm) + 30°C
If it is higher than that, the obtained polymer may have poor fluidity.

The melting point (Tm, °C) of the copolymerized polyester thus obtained must satisfy the following formula (1).

-15<Tm+7.70x-374.4<15
...(1) Here, x in formula (1) is the structural unit (I
The ratio (mol%) of II) to [(I)+(II)+(III)] is shown.

Even if the composition ratio of structural units (I) to (IV) satisfies the above conditions, the composition distribution of the polymer,
If the melting point of equation (1) above is exceeded due to randomness, there are problems such as poor balance between fluidity, heat resistance, and mechanical properties of the molded product, and the polymer tends to decompose at high temperatures. Therefore, it is undesirable. Here, the melting point (Tm) is measured by a differential scanning calorimeter at a heating rate of 20°C.
It refers to the endothermic peak temperature observed when measured at /min, Tm2, which will be described later.

In addition, in the above-mentioned differential calorimetry, the polymerized polymer was heated from room temperature to a temperature above the melting point for 20 minutes.
Endothermic peak temperature (hereinafter abbreviated as Tm1) observed when measuring under heating conditions of °C/min and Tm after observation of Tm1
1 The endothermic peak temperature (hereinafter referred to as Tm2 ) between |Tm1 -Tm2 |≦1
It is preferable that there is a relationship of 0°C, |Tm1 −Tm2
|≦6°C is more preferable. If this temperature difference is greater than 10° C., there is a possibility that a non-uniform structure exists in the polymer, which is not preferable.

In the copolymerized polyester of the present invention, the copolymerization amount of the structural unit (III) with respect to [(I)+(II)+(III)] and the molar ratio of (II)/(III) are important. , (II)/(III) satisfies the scope of the present invention, and the structural unit (III) [(I
)+(II)+(III)], the effects of the present invention are achieved only when the copolymerization amount and melting point are in a constant relationship.

Further, the logarithmic viscosity of this copolyester is 3.0 to 10.0 dl/g, measured in pentafluorophenol at a concentration of 0.1 g/dl and 60°C, and is 3.5 to 7. .5 dl/g is preferred. If the value of logarithmic viscosity is less than 3.0 dl/g, the mechanical properties are insufficient;
If it exceeds 10.0 dl/g, the fluidity will be impaired, which is not preferable in any case.

Furthermore, the molecular weight distribution of the copolymerized polyester of the present invention can be found, for example, in Kobunshi Ronshu Vol. 45, p. 531 (198
It can be measured by the method described in 8), but the weight average molecular weight (MW) and number average molecular weight (M
The value of the ratio MW/MN of N) is preferably less than 3.0, and 2.
More preferably less than 8. If the value of MW/MN is greater than 3.0, fluidity may be impaired, which is not preferable.

The melt viscosity of the copolymerized polyester of the present invention is preferably 100 to 2,000 poise, particularly 100 to 1
,000 poise is preferred.

[0029] This melt viscosity is (melting point (Tm) + 1
This is a value measured using a Koka type flow tester at a temperature of 0)°C and a shear rate of 1,000 s-1.

When polycondensing the copolymerized polyester of the present invention, in addition to the components constituting the structural units (I) to (IV), 4,4'-diphenyldicarboxylic acid,
3,3'-diphenyldicarboxylic acid, 2,2'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid,
4,4'-diphenyl ether dicarboxylic acid, 1,2-
bis(phenoxy)ethane-4,4'-dicarboxylic acid,
1,2-bis(2-chlorophenyxy)ethane-4,4
´-Aromatic dicarboxylic acids such as dicarboxylic acid and isophthalic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hydroquinone, 2,7 -dihydroxynaphthalene, t-butylhydroquinone, 3,3',5,5'-tetramethyl-4
, 4'-dihydroxybiphenyl, phenylhydroquinone, chlorhydroquinone, methylhydroquinone,
4,4'-dihydroxydiphenylsulfone, 4,4'
- Aromatic diols such as dihydroxydiphenylpropane, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenyl ether, ethylene glycol, 1,
Aliphatic and alicyclic diols such as 4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol, and m-hydroxybenzoic acid, 2,6-
Aromatic hydroxycarboxylic acids such as hydroxynaphthoic acid, p-aminophenol, p-aminobenzoic acid, aromatic imide compounds, and the like can be further copolymerized within a small proportion that does not impair the object of the present invention. The copolyester with improved fluidity of the present invention obtained by the melt polymerization method thus obtained has excellent melt fluidity and moldability, and can be processed by ordinary molding methods such as injection molding, extrusion molding, and blow molding. It can be processed into three-dimensional molded products, films, containers, hoses, etc. that have excellent heat resistance and mechanical properties such as rigidity, strength, and impact resistance.

Addition of fillers such as glass fibers, carbon fibers, and asbestos, nucleating agents, pigments, antioxidants, stabilizers, plasticizers, lubricants, mold release agents, and flame retardants to the copolymerized polyester of the present invention Agents and other thermoplastics can be added to impart desired properties.

Furthermore, by adding a filler to the copolymerized polyester of the present invention, the mechanical properties and heat resistance can be further improved.

When a filler is added, the amount added is preferably 200 parts by weight or less, particularly preferably 15 to 130 parts by weight, based on 100 parts by weight of the copolyester.

It is preferable that the deflection temperature under load of the copolyester composition obtained by adding a filler satisfies the formula (2).

Tm-HDT<80°C (2) However, in equation (2), HDT represents the deflection temperature under load (18.6 kgf/cm2) of the molded product.

[0036] The deflection temperature under load may vary due to differences in composition distribution, randomness, or non-uniformity of polymerization.
When formula 2) is satisfied, the melt fluidity of the polymer and the mechanical properties and heat resistance of the molded article will be mutually well balanced.

Fillers that can be preferably used in the present invention include glass fibers, carbon fibers, aromatic polyamide fibers, potassium titanate fibers, gypsum fibers, brass fibers, stainless steel fibers, steel fibers, ceramic fibers, and boron whiskers. Examples include fibrous, powder, granular, or plate-like inorganic fillers such as fiber, rock wool, mica, talc, silica, calcium carbonate, glass beads, glass flakes, glass microballoons, clay, wollastenite, and titanium oxide.

Among the fillers mentioned above, glass fibers are preferably used. The type of glass fiber is not particularly limited as long as it is generally used for reinforcing resins, and can be selected from, for example, long fiber type, single fiber type chopped strand, milled fiber, etc. Furthermore, the glass fibers may be coated or bundled with a thermoplastic resin such as ethylene/vinyl acetate copolymer, a thermosetting resin such as an epoxy resin, or a coupling agent such as a silane type or titanate type, or other It may be treated with a surface treatment agent.

Furthermore, the composition of the present invention may contain antioxidants and heat stabilizers (for example, hindered phenol, hydroquinone, phosphites, and substituted products thereof) to the extent that the object of the present invention is not impaired. , UV absorbers (e.g. resorcinol, salicylates, benzotriazoles, benzophenones, etc.), lubricants and mold release agents (
colorants, plasticizers, including montanic acid and its salts, its esters, its half esters, stearyl alcohol, stearamide and polyethylene wax), dyes (such as nitrosine) and pigments (such as cadmium sulphide, phthalocyanine, carbon black, etc.); Conventional additives such as antistatic agents and other thermoplastics can be added to impart desired properties.

The resin composition of the present invention is preferably melt-kneaded, and known methods can be used for melt-kneading. For example, using a Banbury mixer, rubber roll machine, kneader, single screw or twin screw extruder, etc.
The composition can be prepared by melt-kneading at a temperature of 380°C.

[0041]

[Examples] The present invention will be further explained below with reference to Examples.

Example 1 994 g (7.2 mol) of p-hydroxybenzoic acid (I) and 223 g (1.2 mol) of 4,4'-dihydroxybiphenyl (II) were placed in a reaction vessel equipped with a distillation tube and a stirring blade. ), 2
, 147 g of 6-diacetoxynaphthalene (III) (
0.6 mol), 299 g (1.8 mol) of terephthalic acid (IV)
mol) and 1077 g (10.6 mol) of acetic anhydride were charged, and acetic acid removal polymerization was carried out under the following conditions.

First, a reaction was carried out at 130 to 150° C. for 4 hours under a nitrogen atmosphere. The amount of acetic acid distillate up to this point was 52g.
This was 4.0% of the theoretical distillate amount. After that, 2.
The temperature was raised to 250℃ over 5 hours, and then heated at 250℃ for 2 hours.
．． The reaction continued for 5 hours. The amount of distillate up to this point is 10
The amount was 98 g, which was 83% of the theoretical distillation amount. moreover,
After raising the system temperature to 330℃ over 2 hours, 1
．． The pressure inside the system was reduced to 1.0 mmHg in 5 hours, and then
The reaction was continued for 0 minutes to complete the polycondensation. Before the start of pressure reduction, 1193 g of distillate, which corresponds to 90% of the theoretical distillation amount of acetic acid, had been distilled out. As a result of the above reaction, a beige colored polymer was obtained.

The theoretical structural formula of this polymer is as follows, and the elemental analysis results of this polyester showed good agreement with the theoretical values.

[0045]

[Chemical formula 3]

When the melting point of this polymer was measured using a PerkinElmer DSC-7 model at a heating rate of 20°C/min, the peak temperature of Tm1 was 327°C, Tm1
The peak temperature of 2 was 323°C. Also, formula (1)
The value of (Tm+7.7x-374.4) was 0.19.

Note that the logarithmic viscosity of this polymer (0.1 g/
dl concentration in pentafluorophenol at 60°C) is 5.21 dl/g, the melt viscosity is 333°C,
The fluidity was extremely good at 590 poise at a shear rate of 1000 (1/sec).

[0048] This polymer was processed using a Sumitomo Nestal injection molding machine.
Promat 40/25 (manufactured by Sumitomo Heavy Industries, Ltd.) was used to create impact test pieces with a cylinder temperature of 340°C and a mold temperature of 90°C, measuring 1/4" thick x 2 1/2" long. did. When Izod impact test with cut notch was conducted,
It showed an extremely high value of 75 kgf·cm/cm.

Example 2 45 parts by weight of glass fibers (chopped strands, 3 mm long) were dry-blended with 100 parts by weight of the polymer obtained by the same method as in Example 1, and then mixed at 330°C using a 30 mmφ twin-screw extruder. Melt-kneaded-pelletized.

The obtained pellets were molded into test pieces for measuring deflection temperature under load (HDT) (1/8" width x 1/2" thickness x 5" length) and Izod impact test pieces under the same conditions as in Example 1. For these specimens, the deflection temperature under load (
HDT) and cut-notched Izod impact strength were measured.

As a result, it was found that the deflection temperature under load was 262° C. and the Izod impact strength was 8.2 kgf·cm/cm, indicating good heat resistance and impact resistance.

Examples 3 to 6, Comparative Examples 1 to 3 In a reaction vessel equipped with the same distillation tube and stirring blade as in Example 1, p-hydroxybenzoic acid (I) and 4,4'-dihydroxybiphenyl (
II), 2,6-diacetoxynaphthalene (III)
, terephthalic acid (IV), and acetic anhydride were charged in the composition shown in Table 1, and acetic acid removal polymerization was performed under the same conditions as in Example 1.

The melting point (Tm), logarithmic viscosity, and melt viscosity of the obtained polymer were measured by the method of Example 1. The results are shown in Table 1.

[0054]

[Table 1]

Furthermore, 4 parts of glass fiber (chopped strand 3 mm long) was added to 100 parts by weight of the obtained polymer.
After dry-blending 5 parts by weight, the mixture was melt-kneaded and pelletized using a 30 mmφ twin-screw extruder.

The obtained pellets were molded into test pieces for measuring deflection temperature under load (HDT) and Izod impact test pieces using the injection molding machine of Example 1. These test pieces were measured for deflection temperature under load and notched Izod impact strength. These results are also shown in Table 1.

None of the comparative polymers satisfy the above formula (1). Although the polymer of Comparative Example 1 has a composition that does not contain 4,4'-dihydroxybiphenyl (II) units, it has a higher melt viscosity than the polymer of Examples and cannot be said to have sufficient fluidity. It was also found that the cut notched Izod impact strength was low and the toughness was poor. Moreover, although Comparative Examples 2 and 3 are polymers outside the range of the copolymer composition of the present invention, it can be seen that the melt viscosity is still high and the fluidity is poor.

[0058]

[Effects of the Invention] The copolymerized polyester of the present invention has good fluidity and can be used for various purposes such as electrical and electronic parts because it provides molded products exhibiting excellent heat resistance and mechanical properties. .

Claims (5)

[Claims] Claim 1: Consists of the following structural units (I) to (IV), where the structural unit [(I)+(II)] is [(I)+(II)
)+(III)], 80 to 99 mol% of the structural unit (I
II) is [(I)+(II)+(III)] from 20 to
1 mol%, the molar ratio of structural units (I)/(II) is 75/25 to 95/5, the molar ratio of (II)/(III) is 90/10 to 40/60, and the melting point is (Tm,
°C) satisfies formula (1), and the logarithmic viscosity is 3.0 to 10.0.
A copolymerized polyester having a melt anisotropy of dl/g. [Chemical formula 1] -15<Tm+7.70x-374.4<15
...(1) (However, x in formula (1) is the structural unit (II
The ratio (mol %) of I) to [(I)+(II)+(III)] is shown. ) [Claim 2] Melt viscosity measured at a temperature of melting point (Tm) + 10°C and a shear rate of 1000 s-1 is 100-200.
The copolyester according to claim 1, which has a poise of 0. 3. The copolymerized polyester according to claim 1, which is produced by polymerization at a temperature of melting point (Tm) + 30° C. or lower. 4. A copolyester composition comprising the copolyester according to claim 1 containing a filler. [Claim 5] Deflection temperature under load (HDT, °C, 18.
6kgf/cm2) satisfies the following formula (2).
The copolymerized polyester composition described. Tm-HDT<80(℃)...(2)