JP2505643B2 - Liquid crystal polyester resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a liquid crystal polyester resin composition having excellent heat resistance, moldability, mechanical properties, especially mechanical properties at high temperatures, and anisotropy. .

<Prior Art> In recent years, the demand for higher performance of plastics has increased more and more, and many polymers having various new performances have been developed and put on the market, and in particular, they are characterized by a parallel arrangement of molecular chains. Attention has been paid to the optically anisotropic liquid crystal polymer having excellent mechanical properties.

Examples of the polymer forming the anisotropic molten phase include p-
Liquid crystal polymer obtained by copolymerizing polyethylene terephthalate with hydroxybenzoic acid (JP-A-49-72393), p-
A liquid crystal polymer obtained by copolymerizing hydroxy-2-naphthoic acid (JP-A-54-77691), and a liquid crystal polymer obtained by copolymerizing p-hydroxybenzoic acid with 4,4'-dihydroxybiphenyl, terephthalic acid and isophthalic acid ( Japanese Patent Publication 57-
No. 24407) is known.

Further, it is known that glass fiber is blended for the purpose of improving heat resistance and mechanical strength of the liquid crystal polymer.

<Problems to be Solved by the Invention> However, what has been known so far as this liquid crystal polymer has a low deflection temperature under load of less than 190 ° C. and has insufficient heat resistance, or a deflection temperature under load of 190 ° C. or higher. Although the heat resistance was good, it was difficult to obtain a liquid crystal polymer having a balance between heat resistance and moldability, such as a high liquid crystal starting temperature that was too high to form at 400 ° C. and a high melt viscosity.

Further, when glass fibers are added to the liquid crystal polymer, mechanical strength and heat resistance are improved, but there is a problem that fluidity is lowered. In order to improve this fluidity, there is a method of copolymerizing a monomer containing ethylene oxylet, but there is a problem that heat resistance, especially mechanical properties at high temperature, is deteriorated. Moreover, it was found that even if glass fibers were added to these liquid crystal polymers, the anisotropy was not necessarily sufficiently low and the moldability was not sufficient.

Therefore, it is an object of the present invention to solve the above problems and to obtain a liquid crystal polyester resin composition having excellent heat resistance, mechanical properties at high temperature, excellent moldability, and low anisotropy.

<Means for Solving the Problems> The present inventors have arrived at the present invention as a result of extensive studies to solve the above problems.

That is, the present invention provides the following structural units (I), (II),
Structural unit consisting of (III) and (IV) [(I) + (I
I)] is 75 to 95 mol% of [(I) + (II) + (III)],
Structural unit (III) is [(I) + (II) + (III)] 25-
5 mol% and the molar ratio of structural units (I) / (II) is 75
Melt-moldable liquid crystal polyester resin 1/25 to 95/5 1
With respect to 00 parts by weight, the average fiber diameter is 3 to 9 μm, and the fiber length is
The present invention provides a liquid crystal polyester resin composition obtained by filling 5 to 200 parts by weight of glass fiber of 1000 to 5 × 10 ⁴ μm.

_{O-R 1 -O ...... (II} ) OCH 2 CH 2 -O ...... (III) CO-R 2 -CO ...... (IV) ( provided that, R ₁ in the formula is R ₂ is one or more groups selected from And one or more groups selected from Further, X in the formula represents a hydrogen atom or a chlorine atom. ) In the present invention, it is important to use glass fibers having a specific diameter, whereby a liquid crystal polyester resin composition having excellent anisotropy, which is excellent in heat resistance, mechanical properties at high temperature, and moldability can be obtained. Of.

The structural unit (I) is a structural unit of polyester produced from p-hydroxybenzoic acid, and the structural unit (II)
Is 4,4'-dihydroxybiphenyl, hydroquinone,
2,6-dihydroxynaphthalene, t-butyl hydroquinone. A structural unit formed from one or more aromatic diols selected from 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybiphenyl and phenylhydroquinone,
Structural unit (III) is a structural unit produced from ethylene glycol, structural unit (IV) is terephthalic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-bis (phenoxy) ethane -4,4'-dicarboxylic acid, 1,2-bis (2-chlorophenoxy) ethane-4,
Each of the structural units formed from one or more aromatic dicarboxylic acids selected from 4'-dicarboxylic acid and 4,4'-diphenyl ether dicarboxylic acid is shown.

Of these, R ₁ is But for R ₂ Is most preferred.

Of the above structural units (I) to (IV), the structural unit [(I) + (II)] is 7 of [(I) + (II) + (III)].
It is 5 to 95 mol%, preferably 82 to 93 mol%, and more preferably 85 to 90 mol%.

The structural unit (III) is [(I) + (II) + (III)]
Is 5 to 5 mol%, preferably 18 to 7 mol%, and more preferably 15 to 10 mol%. Structural unit [(I) +
If (II)] is more than 95 mol% of [(I) + (II) + (III)], melt flowability is lowered and solidified during polymerization, and if it is less than 75 mol%, heat resistance becomes poor, which is not preferable. . The molar ratio of structural unit (I) / (II) is 75/25 to 95/5, preferably 78/22 to 93/7. If it is less than 75/25 or more than 95/5, the heat resistance and fluidity are poor, and the object of the present invention cannot be achieved. Also,
The structural unit (IV) is substantially equimolar to the structural unit [(II) + (III)].

The method for producing the liquid crystal polyester used in the present invention is not particularly limited, and it can be produced according to a known polyester polycondensation method.

The liquid crystal polyester used in the present invention preferably has a melt viscosity of 10 to 15,000 poise, and more preferably 20 to 5,000 poise.

The melt viscosity is a value measured by a Koka type flow tester under the condition of (liquid crystal starting temperature + 40 ° C) and shear rate of 1,000 (1 / sec).

On the other hand, the logarithmic viscosity of this liquid crystalline polyester can be measured in pentafluorophenol at a concentration of 0.1 g / dl and 60 ° C., preferably 0.5 to 5.0 dl / g, particularly preferably 1.0 to 3.0 dl / g.

When polycondensing the liquid crystal polyester used in the present invention, in addition to the components constituting the above structural units (I) to (IV), isophthalic acid, 3,3′-diphenyldicarboxylic acid,
Aromatic dicarboxylic acids such as 2,2′-diphenyldicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, chlorohydroquinone, methyl Aromatic diols such as hydroquinone, 4,4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxybenzophenone, 4,4′-dihydroxydiphenyl ether, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, Aliphatic and alicyclic diols such as 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol, and aromatic hydroxycarboxylic acids such as m-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid, or aromatic imide compounds A small proportion that does not impair the object of the present invention It can be allowed to further copolymerization.

The glass fiber used in the present invention is preferably weakly alkaline, which is excellent in mechanical strength and is suitable for reinforcing the resin of liquid crystal polyester.

The average diameter of the glass fibers is in the range of 3 to 9 μm, preferably 4 to 8 μm, more preferably 6 μm. The fiber length is 1.00 to 5 × 10 ⁴ μm, preferably 1,500 to 1
It is 3,000 μm. The filling amount is 5 to 200 parts by weight, preferably 10 to 100 parts by weight, based on the liquid crystal polyester.

The average diameter of the glass fiber is less than 3 μm or 9 μm
If it is larger, the reinforcing effect is small, so that the effect of reducing anisotropy is small and the moldability is not sufficient.

Further, it is preferable to add an organic flame retardant to this resin composition, since not only flame retardancy is imparted thereto, but also this anisotropy reducing effect and moldability are further improved.

The method for producing the glass fiber having the above-mentioned diameter is not particularly limited, but it is preferable to cut a spun long fiber having a uniform diameter.

As the glass fiber, those treated with a silane coupling agent are preferably used, and an epoxysilane type is particularly preferable. Further, it is preferably treated with an epoxysilane-based sizing agent.

When flame retardancy is required in the present invention, an organic flame retardant can be added, and the organic flame retardant is an organic bromine compound and / or an organic phosphorus compound, and the organic bromine compound is bromine in the molecule. Those having atoms, particularly those having a bromine content of 20% by weight or more are preferable. Specifically, low molecular weight organic bromine compounds such as decabromodiphenyl ether, ethylene bis- (tetrabromophthalimide), brominated polycarbonate (for example, a polycarbonate oligomer produced from brominated bisphenol A as a raw material or a copolymer thereof with bisphenol A). ), Brominated epoxy compounds (for example, diepoxy compounds produced by reaction of brominated bisphenol A with epichlorohydrin, monoepoxy compounds obtained by reaction of brominated phenols with epichlorohydrin), poly (brominated benzyl acrylate), bromine Polyphenylene ether, brominated bisphenol A, condensate of cyanuric chloride and brominated phenol, brominated polystyrene,
Cross-linked brominated polystyrene, cross-linked brominated poly-α-methylstyrene and other halogenated polymers and oligomers, or mixtures thereof may be mentioned, among which ethylene bis- (tetrabromophthalimide), brominated epoxy oligomers or polymers, Brominated epoxy oligomers or polymers, brominated polystyrenes, cross-linked brominated polystyrenes, brominated polyphenylene ethers and brominated polycarbonates are preferred, with ethylene bis- (tetrabromophthalimide), brominated polystyrenes and brominated polycarbonates being particularly preferred.

The amount of these organic flame retardants added is 100% liquid crystal polyester.
It is preferably 0.2 to 30 parts by weight, more preferably 1 to 20 parts by weight per part by weight, but since the flame retardancy is closely related to the copolymerization amount of the structural unit (III) of the liquid crystal polyester, It is preferable that the addition amount is as follows. That is, the amount of the organic bromine compound to be added is preferably 60 to 280 parts by weight, particularly preferably 100 to 200 parts by weight, per 100 parts by weight of the structural unit (III) in the liquid crystal polyester.

On the other hand, the organic phosphorus compound used in the present invention is
Having a phosphorus atom in the molecule, phosphoric acid, phosphorous acid, compounds synthesized from phosphonic acid, phosphine, phosphine oxide, compounds such as phospholane and compounds of the following structural formula and these compounds as at least one component It is a polymer contained.

Examples of this polymer include polymers having the following structural units.

The most preferable organic phosphorus compound among these is the following polymer.

(However, R ₃ represents an alkyl group, an aryl group, and R ₄ represents a chain-like or cyclic alkylene residue or an arylene residue.) Incidentally, a part of these organic phosphorus compounds may be a metal salt. The organic phosphorus compound is added in an amount of 0.2 to 30 parts by weight, preferably 0.5 to 15 parts by weight, based on 100 parts by weight of the liquid crystal polyester 100 having the structural formulas (I), (II), (III) and (IV). The amount is preferably 2 to 150 parts by weight, and particularly preferably 10 to 100 parts by weight, based on 100 parts by weight of the structural unit (III) in the liquid crystal polyester.

Further, in the present invention, a small amount of an organic bromine compound, preferably brominated polystyrene, brominated polycarbonate, brominated epoxy polymer, brominated polyphenylene ether may be used in combination, and a bromine-containing organic compound such as a polymer composed of an organic phosphorus compound may be used. It may be a phosphorus compound.

In the liquid crystal polyester of the present invention, the structural unit (III) is 5 to 25 mol% of the structural unit [(I) + (II) + (III)]. In the test (ASTM D790 standard), it can be V-0 at a thickness of 1/32 ″. When the structural unit (III) is less than 5 mol%, the melting point of the liquid crystal polyester becomes high, so that the liquid crystal polyester is melted by the flame retardant. It is not preferable because it decomposes, the degree of polymerization is lowered, the mechanical properties are deteriorated even if a filler is added, and the molded product drips when burned.On the other hand, when the structural unit (III) is more than 25 mol%. Not only the heat resistance such as deflection temperature under load is greatly lowered, but also it is necessary to add a large amount of organic bromine compounds and organic phosphorus compounds in order to impart flame retardancy, and flame retardant aids such as antimony compounds are added. Mechanical as it needs to be added Undesirable because sex is greatly reduced.

In the present invention, it is possible to further contain the following fillers, carbon fiber, aromatic polyamide fiber, potassium titanate fiber, gypsum fiber, brass fiber, stainless fiber, steel fiber, ceramic fiber, boron fisca fiber,
Fibers such as mica, talc, silica, calcium carbonate, glass beads, glass flakes, glass microballoons, clay, wollastonite, titanium oxide and graphite,
Examples thereof include powder, granular or plate-like inorganic fillers.

Furthermore, the composition of the present invention contains an antioxidant and a heat stabilizer (for example, hindered phenol, hydroquinone, phosphites and their substitution products), and UV absorption within a range that does not impair the object of the present invention. Agents (eg resorcinol, salicylate, benzotriazole, benzophenone, etc.) lubricants and mold release agents (montanic acid and its salts, its esters, its half esters, stearyl alcohol, stearamide and polyethylene wax, etc.), dyes (eg nitrocin) and Colorants, plasticizers, including pigments (eg cadmium sulfide, phthalocyanine, carbon black, etc.),
Conventional additives such as antistatic agents and other thermoplastic resins can be added to impart predetermined characteristics.

The resin composition of the present invention is preferably melt-kneaded, and a known method can be used for melt-kneading. For example, using a Banbury mixer, a rubber roll machine, a kneader, a single-screw or twin-screw extruder, and the like, the composition can be melt-kneaded at a temperature of 200 to 350 ° C.

<Examples> Hereinafter, the present invention will be described in detail with reference to Examples.

Reference Example 1 881 parts by weight of p-hydroxybenzoic acid, 158 parts by weight of 4,4′-dihydroxydiphenyl, 907 parts by weight of acetic anhydride, 141 parts by weight of terephthalic acid and 245 parts by weight of polyethylene terephthalate having an intrinsic viscosity of about 0.6 dl / g. The reaction vessel was equipped with a stirring blade and a distillation tube, and deacetic acid polycondensation was carried out under the following conditions.

First, in a nitrogen gas atmosphere at 100 to 250 ° C for 5 hours, 250 to 3
After reacting at 00 ℃ for 1.5 hours, 0.5mmHg at 300 ℃ for 1 hour
When the pressure was reduced to 2, and the reaction was further continued for 2.25 hours to complete the polycondensation, almost the theoretical amount of acetic acid flowed out to obtain a resin (a) having the following theoretical structural formula.

k / l / m / n = 75/10/15/25 Moreover, the polyester was placed on the sample stage of a polarizing microscope and the temperature was raised to confirm the optical anisotropy. As a result, the liquid crystal starting temperature was 264 ° C. And showed optical anisotropy. The inherent viscosity of this polyester (measured in pentafluorophenol at a concentration of 0.1 g / dl at 60 ° C) is 1.96 dl / g, 304
The melt viscosity at ℃ and shear rate of 1.000 (1 / sec) was 910 poise.

Example 1 For 100 parts by weight of the liquid crystal polyester (a) of Reference Example 1, 50 parts by weight of glass fiber having a fiber diameter of 6 μm and a length of 3,000 μm and brominated polystyrene (“Pyrocheck” 68PB manufactured by Nissan Fellow Co., Ltd.) ) After mixing 8.5 parts by weight with a ribbon blender, the mixture was melt-kneaded and pelletized at 300 ° C using a 40 mmφ vented extruder. Next, the pellets obtained were subjected to a Sumitomo Nestal injection molding machine "Promat" (Sumitomo Heavy Industries, Ltd.), cylinder temperature 300 ℃, mold temperature 90
Combustion test piece (1/32 "and 1/8" x 1/2 "x
5 "), test piece for measurement (1/8" x 1/2 "x 5") and 2m
A square plate measuring m × 70 mm × 70 mm was formed. Vertical combustion test according to UL94 standard was performed on these test pieces according to ASTM D
Bending test measurements were performed according to the 790 standard. Regarding the flexural modulus, the flexural modulus at 50 to 150 ° C is 2
The flexural modulus retention rate was calculated as compared with that at 3 ° C. On the other hand, a square plate is used to measure the molding shrinkage perpendicular to the flow direction, and the square plate is cut into a width of 14 mm in the flow direction and at the right angle, and the bending elastic modulus is set at a strain rate of 1 mm / min and a span bending distance of 40 mm. Was measured and the ratio was used as a measure of anisotropy.

The moldability is evaluated by using the above-mentioned molding machine
The length (bar flow length) of a 0.5 mm thick × 12.7 mm wide test piece was determined under the conditions of 99% and an injection pressure of 500 kgc / cm ² .

Example 2, Comparative Examples 1 to 4 Glass fiber (b) and flame retardant (c) were added to the liquid crystal polyester (a) of Reference Example 1 in the types and proportions shown in Table 1, and after mixing with a ribbon blender 40 mmφ vent It was melt-kneaded and pelletized at 260 to 300 ° C using an attached extruder. Next, the obtained pellets are subjected to the Sumitomo Nestal injection molding machine "Promat" 40/25 (Sumitomo Heavy Industries, Ltd.), and carried out under the conditions of a cylinder temperature of 260 to 300 ° C and a mold temperature of 40 to 90 ° C. A molded product similar to that of Example 1 was obtained.

These molded products were evaluated in the same manner as in Example 1.

 Table 1 shows the results.

As is clear from Table 1, the molded products made of the liquid crystal polyester composition of the present invention have a higher flexural modulus at high temperature than the molded products of Comparative Examples 1 to 4, and have an anisotropy reducing effect and a rod flow length. It turns out that is large.

<Effects of the Invention> With the liquid crystal polyester composition of the present invention, a resin composition having excellent heat resistance, moldability, mechanical properties, especially mechanical properties at high temperatures, and anisotropy can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-63-139715 (JP, A) JP-A-63-118325 (JP, A) JP-A-63-30523 (JP, A) JP-A 64-- 61087 (JP, A) JP-A 63-101448 (JP, A) JP-A 1-245047 (JP, A)

Claims (2)

(57) [Claims] 1. A structural unit [(I) + (II)] consisting of the following structural units (I), (II), (III) and (IV) is [(I) + (II) + (III)] Of the structural unit (III) is 25 to 5 mol% of [(I) + (II) + (III)], and the molar ratio of the structural unit (I) / (II) is 75/95%. 25-9
The average fiber diameter is 3 to 9 μm and the fiber length is 1000 to 100 parts by weight of melt-moldable liquid crystal polyester resin of 5/5.
A liquid crystal polyester resin composition obtained by filling 5 to 200 parts by weight of 5 × 10 ⁴ μm glass fiber. _{O-R 1 -O ...... (II} ) OCH 2 CH 2 -O ...... (III) CO-R 2 -CO ...... (IV) ( provided that, R ₁ in the formula is R ₂ is one or more groups selected from And one or more groups selected from Further, X in the formula represents a hydrogen atom or a chlorine atom. ) 2. The liquid crystal polyester composition according to claim 1, further comprising 0.2 to 30 parts by weight of an organic flame retardant with respect to 100 parts by weight of the liquid crystal polyester.