JPH06157726A - Molded article of polyphenylene and its production - Google Patents

Abstract

PURPOSE:To obtain a molded article having low anisotropy, high elastic modulus, light weight and excellent recyclability and useful as a substitute for inorganic materials such as metal and ceramics by injection-molding a polyphenylene composed of a specific constituent unit. CONSTITUTION:This molded article is produced by the injection molding of a polyphenylene composed mainly of a constituent unit of the formula [R is univalent hydrocarbon group obtained by linking one to three 6-10C aromatic groups (which may be substituted with halogen, etc.) through one or more bonds selected from direct bond, O, CO, COO, OCO, CONH, N=N, CH=N and S; X is direct bond, O, etc.; (m) is 1-4]. The injection molding is carried out at the resin temperature of 250-400 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded article obtained by an injection molding method using a polyphenylene compound which has an extremely high elastic modulus, little anisotropy, and is excellent in lightweight and recyclability. .

[0002]

2. Description of the Related Art Generally, organic polymers are lighter in weight, have better moldability and are excellent in productivity as compared with inorganic materials such as metals and ceramics, and thus have replaced these inorganic materials in many fields.
On the other hand, a drawback of organic polymers is that they have a lower elastic modulus than those inorganic materials. Therefore, it was difficult to use it for various engineering materials such as structural materials where rigidity is important. Therefore, various polymers have been designed and synthesized for improved modulus.

In order to improve the elastic modulus, the linearity of the primary structure of the polymer main chain should be increased as much as possible, and the intermolecular force should be increased so that the main chain should not be extended or rotated. It was known that this can be achieved by designing.

[0004]

However, the improvement of the elastic modulus and the melt moldability are two contradictory events, and in fact, the polymers known to date have a high elastic modulus and a high productivity. What can be molded by the injection molding method, which is a molding method, is only about the liquid crystalline polyesters known as liquid crystal polymers, and other high elastic modulus polymers can be used if solution molding with poor productivity can be performed. It was still a good one, and it was usually insoluble or infusible and could not be easily molded into an arbitrary shape.

Liquid crystal polymers having melt moldability can generally be injection-molded, but due to their liquid crystallinity, they have a high elastic modulus in a certain direction, but a remarkably elastic modulus in a direction perpendicular to that direction. It has a very anisotropic property that the value becomes low, and when considered as a structural material, it was difficult to use. On the other hand, polyphenylenes have been developed as a high elastic modulus polymer. For example, unsubstituted poly-p-phenylene was expected to have a high elastic modulus, but was insoluble and infusible, and had poor moldability. Therefore, as in WO 89/07617 and JP-A-2-45521, attempts have been made to improve the solubility by introducing a side chain into the phenylene group of poly-p-phenylene, but in solution molding the productivity is improved. It was inferior in industrial utility.

Further, as disclosed in JP-A-3-182544, polyphenylene is used by mixing it with another melt-moldable polymer in order to impart melt-moldability, but a plurality of polymers are used. Good properties cannot be expressed without optimal mixing, and when mixed with a polymer having a low elastic modulus, a material having an essentially high elastic modulus could not be obtained.

[0007]

[Means for Solving the Problems] The inventors of the present invention obtained a molded product having a high elastic modulus and a small anisotropy by an injection molding method which is excellent in productivity, and thus was excellent in lightness and recyclability. As a result of synthesizing and evaluating various polymers with a rigid main chain structure in order to develop materials, surprisingly, polyphenylene with a specific structure breaks the conventional wisdom and has a so-called liquid crystal with a high elastic modulus. The present invention has been accomplished, and it was found that a molded product, unlike a polymer, in which the elastic modulus has little directional dependence, can be obtained by an injection molding method having excellent productivity. That is, the gist of the present invention is a molded product obtained by injection-molding a polyphenylene mainly composed of the structural unit (A) represented by the following general formula.

[0008]

[Chemical 4]

(In the formula, R has 6 to 10 carbon atoms which may be substituted with a halogen atom, an alkyl group or an alkoxy group.
1 to 3 aromatic groups are directly bonded, -O-, -CO-,-
COO-, -OCO-, -CONH-, -N = N-,-
It represents a monovalent hydrocarbon group which is linked by at least one bond selected from CH = N- and -S-.

X is a direct bond, --O--, --CO--, --C.
OO-, -OCO-, -CONH-, -N = N-, -C
Represents at least one bond selected from H = N- and -S-. m represents an integer of 1 to 4. ). Hereinafter, the present invention will be described in detail. The polyphenylene of the present invention is mainly characterized by comprising a structural unit (A) represented by the following general formula.

[0011]

[Chemical 5]

(In the formula, R represents 6 to 10 carbon atoms which may be substituted with a halogen atom, an alkyl group or an alkoxy group.
1 to 3 aromatic groups are directly bonded, -O-, -CO-,-
COO-, -OCO-, -CONH-, -N = N-,-
It represents a monovalent hydrocarbon group which is linked by at least one bond selected from CH = N- and -S-.

X is a direct bond, --O--, --CO--, --C.
OO-, -OCO-, -CONH-, -N = N-, -C
Represents at least one bond selected from H = N- and -S-. m represents an integer of 1 to 4. ) The -X-R group substituting the phenylene group of the main chain can be selected depending on the purpose and the availability of the monomer, but is preferably

[0014]

[Chemical 6]

[0015] The number of aromatic groups contained in R is 1 to 3. The melt moldability improves as the number of aromatic groups increases and the overall length increases, and as the hydrogen of the aromatic group is replaced with another substituent, the elastic modulus tends to decrease. In order to improve the melt moldability by changing the structure of the side chain, it is better to extend the length of some substituents by making the number of chains of aromatic groups longer than 4 to make it a block copolymer. It is also possible to introduce a long-chain aliphatic into the side chain to improve the melt moldability, but it is disadvantageous in terms of heat resistance and the synthesis of the monomer becomes difficult.

Polymerization degree (n) of the polyphenylene of the present invention
Is preferably 30 or more, more preferably 50 on average.
To 200. In order to increase the elastic modulus as much as possible, it is preferable that the phenyl groups in the main chain are essentially composed of only 100% para bonds, but if the highest elastic modulus is not required for some purposes, some meta bonds or orthos may be used. A bond may be included. In this case, the elastic modulus is lower than that in the case where all are para-bonds, but conversely, elongation and toughness are improved. In order to secure a high elastic modulus, it is preferable that the proportion of the constituent units other than the para bond is 30 mol% or less, but the proportion may be determined in consideration of the balance of the physical properties of the entire material.

The substituents -X-R need not all be the same, and mono- and poly-substitutions may be mixed. In the present invention, the structural unit (A) is preferably contained in at least 70 mol% in all structural units.
Examples of the other structural unit include a structural unit composed of an unsubstituted phenylene group, but the proportion thereof is 30 mol% of the whole.
It is preferably less than. This is because if the non-substitution ratio is too high, the melting point becomes high, and finally the injection molding which is the object of the present invention becomes impossible.

Various methods are known for synthesizing the polyphenylene of the present invention, and Japanese Patent Publication No. 59-523.
Alternatively, the method disclosed in JP-A-61-233014, that is, an aromatic dihalogen compound in an aprotic solvent under a transition metal catalyst such as nickel or palladium,
It can be easily obtained by reacting in the presence of an appropriate ligand, co-catalyst and reducing agent.

In the present invention, among the above polyphenylenes, particularly those having a molecular weight distribution {ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw / Mn)} of 4 or less are injection-molded. Surprisingly, a molded product having improved moldability and good physical properties can be obtained. The molecular weight distribution of the polyphenylene of the present invention can be measured by a usual GPC method, and is usually obtained based on polystyrene. The ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 1 if there is no molecular weight distribution, but it is generally considerably wide in the polycondensation type polymer such as the present invention. On the other hand, considering the relationship between the melt viscosity and the molecular weight distribution, in the conventional coiled polymer with a low elastic modulus, the wider the molecular weight distribution is, the larger the contribution of the low molecular weight portion becomes, as long as the molecular weight distribution is similar. The viscosity tended to decrease. Therefore, the wider the molecular weight distribution, the better the injection moldability.

Surprisingly, however, in the case of the rigid polymer polyphenylene used in the present invention, contrary to the conventional knowledge, it was found that the narrower the molecular weight distribution, the lower the melt viscosity. In the case of the present invention, the molecular weight distribution is preferably 4 or less, more preferably 3 or less. Even if the molecular weight distribution exceeds 4, the melt moldability is exhibited, but the moldability decreases with the same molecular weight. Conversely, when the melt viscosity is the same, the molecular weight distribution is 4
If the following is the case, a polymer having such a large molecular weight can be used, so that the physical properties of the obtained molded product are improved even with the same moldability.

There are no particular restrictions on the control of the molecular weight distribution, but it is preferable to sufficiently stir during the polymerization so that the monomers react uniformly and to improve the purity of the monomers and the catalyst used. Further, by strictly controlling the temperature, a crosslinking reaction does not occur and a polymer having a narrow molecular weight distribution can be obtained. The melt viscosity of the polyphenylene of the present application has a shear rate of 100.
At 0 / sec, it is preferably in the range of 1000 to 50000 poise at any temperature in the range of 250 to 400 ° C. More preferably, 3000-20
It is in the range of 000 poise. If the melt viscosity is higher than 50,000 poise, injection molding is difficult. If the melt viscosity is lower than 1,000 poise, injection molding is easy, but the physical properties are significantly deteriorated. That is, although the melt viscosity is lowered by lowering the molecular weight, mechanical properties are inevitably lowered. On the other hand, it is not impossible to give, for example, shear liquid crystallinity to the polyphenylene by the combination of the molecular design of the polyphenylene of the present application and the molding conditions, and in that case, the melt viscosity of 1000 poise or less is not accompanied by the deterioration of the physical properties. Can be more easily injection molded. However, imparting liquid crystallinity to the polyphenylene of the present application is not always preferable when it is desired to obtain a molded product having an isotropically high elastic modulus because the molded product obtained tends to have anisotropy.

The polyphenylene of the present invention can be easily injection-molded using an ordinary commercially available injection molding machine to obtain a molded product having an arbitrary shape. Optimum conditions vary depending on the polymer without using any special method or technique in the injection molding method, but for example, molding is performed at a resin temperature of about 250 ° C. to 400 ° C. and a mold temperature of room temperature to about 200 ° C. Is preferred. It should be noted that these conditions can be greatly influenced by the type of molding machine, the shape of the target molded article, etc., and are not limited to these molding conditions. If a particularly large molded piece is to be obtained for the purpose, use a molding method with improved injection molding, such as injection press molding that performs press molding after injection molding or injection compression molding that simultaneously performs injection molding and compression molding. It is also possible to obtain a molded product by combining injection molding with another molding method such as extrusion molding.

In the injection molding method, in general, shear orientation of polymer chains easily occurs due to shear between the polymer melt and the mold, but in the polymer of the present invention, the shear orientation is higher than that of other high elastic modulus polymers, especially liquid crystal polymers. Is less likely to occur and it is easy to obtain a molded product having a high elastic modulus isotropically. However, if the polymer melt is made to pass through a too thin channel at a high speed, anisotropy due to shear orientation is likely to occur. Therefore, it is advisable to prevent anisotropy by devising a die design or the like. If the polymer shown in the present invention is used, and more preferably the shape of the mold is devised, the bending elastic modulus in at least one plane can easily be 5 GPa or more and / or the bending elastic modulus in any direction. It is possible to obtain a molded product having a deviation of ± 20% or less.

On the contrary, when a high elastic modulus is required in a certain direction even if the anisotropy is strong depending on the purpose, shearing occurs by increasing the injection speed or shortening the distance between the mold surfaces. A molded body having a higher elastic modulus can be obtained by making it easier. In this case, it is possible to easily obtain a molded product having a bending elastic modulus of at least 10 GPa in at least one direction.

In the present invention, the above-mentioned high elastic modulus and low anisotropy are exhibited without adding an inorganic filler for strengthening or lowering anisotropy in the polymer, which is lighter and more recyclable. However, if the elastic modulus and cost are more important than the lightness and recyclability, inorganic fillers such as GF, CF, silica and mica may be added.

Since the injection-molded article of the present invention is lightweight and has a high elastic modulus and a low anisotropic material, it can be used as a material for replacing inorganic materials such as metals and ceramics in parts for vehicles, ships, aircraft and exterior parts. It can be used in a very large number of fields such as plate and inner wall materials, wall materials for houses and buildings, electric and electronic materials such as substrates, exterior materials and various parts.

[0027]

The present invention will be described in more detail with reference to the following examples. In the following, “part” means “part by weight”. (Reference Example 1) 2,5-Dichlorobenzoic acid was reacted with thionyl chloride to synthesize the corresponding acid chloride. Next, this acid chloride compound and benzene or diphenyl ether are subjected to Friedel-Crafts reaction in the presence of aluminum chloride, and each reaction crude product is recrystallized twice with ethanol to obtain dichloro-form monomers, respectively 2,
5-dichlorobenzophenone (monomer 1), 2,5-
A purified product of dichloro-4'-phenoxybenzophenone (monomer 2) was obtained.

Reference Example 2 Monomer 1 (2890 parts),
NiCl ₂ (50 parts), triphenylphosphine (7
50 parts), sodium iodide (150 parts), and zinc powder (1200 parts) were dispersed in NMP (15000 parts) with stirring, heated, and reacted at 95 ° C for 2 hours. After the viscous solution was precipitated in methanol / dilute hydrochloric acid to dissolve the residual metal, it was washed with water, methanol and acetone to recover polymer 1 almost quantitatively. In NMP solvent (30 ° C)
Ηinh measured at 1.8 dl / g, and 32
The melt viscosity at 0 ° C. and a shear rate of 1000 / sec was 40,000 poise.

Reference Example 3 Polymer 2 was synthesized in the same manner as in Reference Example 2 except that 3950 parts of Monomer 2 was used instead of Monomer 1 of Reference Example 2, and Polymer 2 was recovered almost quantitatively. . Ηinh measured in an NMP solvent (30 ° C.) was 2.3 dl / g, and the melt viscosity at 280 ° C. and a shear rate of 1000 / sec was 6,000 poise. When this polymer was measured by a light scattering method in an NMP solvent, the Mw was 68,000 and the radius of gyration was 300 〓. It was calculated from the radius of gyration assuming that the polymer was completely extended in this solvent. Mn is 19000
Met.

Comparative Example 1 A polymer was synthesized in the same manner as in Reference Example except that 1850 parts of commercially available 2,5-dichlorotoluene was used in place of Monomer 1 of Reference Example 2, and a powder of Polymer 3 was recovered. . This polymer was infusible up to 400 ° C.

Example 1 Various polymers having different molecular weight distributions were synthesized in the same manner as the polymer 2 except that the same monomer as the polymer 2 was used and the purity of the monomer was changed, and the solution viscosity, melt viscosity and The molecular weight distribution was measured by GPC. Incidentally, ηinh is 0.5 g / dl, 30 ° C.,
Measured in NMP solvent. The melt viscosity is 280 ° C,
It is a value at γ = 1000. Mw and Mn are NMP
It was calculated in terms of polystyrene in a solvent at 40 ° C.

[0032]

[Table 1]

Comparative Example 2 Using the same monomer as Polymer 2, various polymers having different molecular weight distributions were synthesized in the same manner as in Example 1, and the solution viscosity, melt viscosity and GPC were used to determine the molecular weight distribution in the same manner as in Example 1. Was measured.

[0034]

[Table 2]

Example 2 Polymer 2 and polymer 3 were used for injection molding at a molding temperature of 290 ° C. and a mold temperature of 120 ° C. to obtain a molded piece (30 × 3 × 1 mm thick), and its bending properties were evaluated. It was measured. Bending properties are ASTM-D-7
It measured according to 90. Polymer 2: Bending elastic modulus 15.5 GPa, bending strength 19
5 MPa, bending strain 1.3% Polymer 3: bending elastic modulus 16.6 GPa, bending strength 24
1 MPa, bending strain 1.6%

Comparative Example 3 Polymer 8 was injection-molded at a molding temperature of 290 ° C. and a mold temperature of 120 ° C. to obtain molded pieces (thickness of 30 × 3 × 1 mm), the bending properties of which were determined in Example 2. It measured similarly to. Polymer 8: Flexural modulus 13.0 GPa, flexural strength 13
6 MPa, bending strain 1.1%

Example 3 Polymer 4 synthesized using the same monomer as polymer 2 (ηinh: 3.6, melt viscosity: 10,000 poise (share rate = 1000 / sec,
(280 ° C.) was injection-molded at a molding temperature of 350 ° C. and a mold temperature of 140 ° C. to obtain various molded pieces, and their bending properties were measured. In the case of a flat plate having a thickness of 80 mm × 80 mm × 3 mm: the bending elastic modulus is 45 in the MD direction, the TD direction, and from them
8.8 GPa and 6.8 GPa respectively in the ° direction
And 7.6 GPa. The bending strengths were 90 MPa, 71 MPa, and 65 MPa, respectively, and the bending strains were 1.1%, 1.1%, and 0.9%, respectively. 1/8 in. In the case of ASTM type 1 dumbbell piece: Flexural modulus 14.0 GPa, flexural strength; 91 MPa, flexural strain;
It was 2.9%. Molding shrinkage rate of flat plate 80 mm x 80 mm x 3 mm: M
It was −0.26% in the D direction and −0.48% in the TD direction. The molding shrinkage was measured according to JIS-K-6911.

Comparative Example 4 A commercially available liquid crystal polymer (a liquid crystal polyester composed of polyethylene terephthalate and oxybenzoic acid) was injection-molded at a molding temperature of 300 ° C. and a mold temperature of 100 ° C., and bending properties of various molded pieces obtained. Was measured. In the case of a flat plate having a thickness of 80 mm × 80 mm × 3 mm: the bending elastic modulus is 45 in the MD direction, the TD direction, and from them
6.4 GPa and 1.7 GPa in the ° direction
And 2.2 GPa. The bending strength was 101 MPa, 46 MPa, 55 MPa, and the bending strains were 3.4%, 6.6%, and 4.5%, respectively. 1/8 in. For ASTM type 1 dumbbell piece: Flexural modulus 6.9 GPa, flexural strength; 104 MPa, flexural strain;
It was 3.1%. Molding shrinkage rate of flat plate 80 mm x 80 mm x 3 mm: M
It was −0.06% in the D direction and −1.20% in the TD direction.

[0039]

INDUSTRIAL APPLICABILITY The injection-molded article of the present invention is lightweight and has a high elastic modulus and has a low anisotropy of mechanical properties, so that it can be used in various fields as a substitute for inorganic materials such as metals and ceramics. .

Claims (7)

[Claims] 1. A molded product of polyphenylene obtained by injection molding a polyphenylene mainly composed of a structural unit (A) represented by the following general formula. [Chemical 1] (In the formula, R is an aromatic group 1 having 6 to 10 carbon atoms which may be substituted with a halogen atom, an alkyl group or an alkoxy group.
~ 3 are directly bonded, -O-, -CO-, -COO-,-
It represents a monovalent hydrocarbon group formed by connecting at least one bond selected from OCO-, -CONH-, -N = N-, -CH = N- and -S-. X is a direct bond, -O-, -CO-, -COO-, -OCO-, -C.
It represents at least one bond selected from ONH-, -N = N-, -CH = N- and -S-. m is 1 to 4
Represents the integer. ) 2. The molded product according to claim 1, wherein at least 90 mol% of the structural unit (A) is a structural unit represented by the following general formula. [Chemical 2] 3. The molded product according to claim 1, wherein at least 90 mol% of the structural unit (A) is a structural unit represented by the following general formula. [Chemical 3] 4. The molded product according to claim 1, wherein the structural unit (A) accounts for 70 mol% or more of all structural units. 5. Polyphenylene molecular weight distribution {ratio of weight average molecular weight Mw to number average molecular weight Mn (Mw / Mn)}
Is 4 or less, The molded object according to any one of claims 1 to 4. 6. The melt viscosity of polyphenylene at a shear rate of 1000 / sec is 1000 at 250 to 400 ° C.
The molded product according to any one of claims 1 to 5, which has a porosity of 50,000 poises. 7. The method for producing a molded article according to claim 1, wherein the molding is performed at a resin temperature of 250 to 400 ° C.