JP2642129B2 - Glass fiber reinforced polyester resin composition with excellent crystallinity - Google Patents

Description

The present invention relates to a glass fiber reinforced polyester resin composition having excellent crystallization properties, improved moldability, and excellent thermal and mechanical properties. About.

[Prior Art] Polyalkylene terephthalate is very important as a raw material for producing fibers, films or molded products. Among them, polyethylene terephthalate (hereinafter abbreviated as PET) is particularly suitable for producing various industrial products because of its many excellent physical properties such as heat resistance, chemical resistance, mechanical properties, and electrical properties. However, when this PET is to be used as an injection-molded article for plastics applications, it is necessary to use a high mold temperature (about 140 ° C) in the production of the molded article.
° C) and a relatively long processing time is required. That is, it is difficult to perform molding at such a high temperature with a general molding apparatus used for molding other thermoplastic resins such as polyamide, polypropylene, polyacetal, and polybutylene terephthalate. Therefore, it is necessary to provide a special molding apparatus. In addition, there is a disadvantage that the operation for raising the temperature becomes complicated, and the working efficiency is remarkably reduced. Further, there is a disadvantage that the molding cost is increased due to a long molding cycle. Such a drawback in the molding of PET is attributable to the crystallization characteristics of PET, which is different from other thermoplastic resins, that is, the crystallization speed is slow, and it is important to improve this point.

Although many methods are known as means for improving the crystallization rate of PET, a method of blending a PET with a crystal nucleating agent (nucleating agent) or a crystallization accelerator is generally adopted. For example, inorganic compounds such as talc, metal oxides such as calcium oxide, and metal salts of organic carboxylic acids such as sodium benzoate and sodium stearate (Japanese Patent Publication No.
29977, JP-B-47-14502), α-olefin and α,
Ionic copolymers composed of metal salts of β-unsaturated carboxylic acids (JP-B-45-22625), alkali metal salts of polycarboxylic acids (JP-B-48-4098) and the like are used as nucleating agents. JP-A-59-161427 discloses that a copolymer of an alkali metal salt of sulfonic acid and polyester can be an effective nucleating agent for a polyester composition.

Further, JP-A-56-92918 discloses a method in which a terminal group of a polyester is converted to a metal salt such as a carboxylic acid.

[Problems to be Solved by the Invention] However, in the methods described in JP-B-46-29977 and JP-B-47-14502, the crystallization rate has not yet been sufficiently improved, and a further improvement in the crystallization rate is desired. The disadvantage is that the incorporation of nucleating agents and crystallization promoters has undesirable side effects. For example, among known nucleating agents, when an alkali metal salt of an organic carboxylic acid having a relatively large crystallization promoting effect is used, there is a problem that the molecular weight of PET is reduced and the mechanical properties of a molded article are reduced. Even the method described in JP-B-45-26225 causes problems of a decrease in mechanical strength of the molded article and deterioration of coloring during heating. Even in the method described in JP-B-48-4098, the reduction of the mechanical strength of the molded article is inevitable.

In addition, since many of the known nucleating agents have poor uniform dispersibility in a polymer, the resulting molded product is non-uniform with respect to crystallinity, and is inferior in terms of dimensional stability and shape stability. It will be.

In the method described in JP-A-59-161427, it is difficult to obtain a remarkable crystallization promoting effect. In the method described in JP-A-56-92918, a metal base such as a carboxylic acid is introduced only at the terminal of a molecule, and therefore, in ordinary polyesters, only two are introduced per molecule, which is remarkable. It is difficult to obtain a sufficient crystallization promoting effect, and in order to obtain a polyester having a sufficiently high molecular weight, it is necessary to carry out a polycondensation reaction for a longer time than usual, so that the polymer is disadvantageously colored.

Thus, it is an object of the present invention to provide an improved thermal,
An object of the present invention is to provide a glass fiber reinforced polyester resin composition which gives a molded article having excellent mechanical properties.

[Means for Solving the Problems] The present inventors have found that the crystallization speed is low and the moldability is inferior without impairing the excellent thermal and physical properties characteristic of PET.
As a result of intensive studies to improve the shortcomings of PET, as a component of polyester, in addition to the main components terephthalic acid component and ethylene glycol component, a co-functional component containing a polyfunctional component having a carboxylic acid alkali metal base was included. The inventors have found that a polymerized polyester can solve the above problems, and have completed the present invention.

That is, the present invention relates to (A) a polyester comprising a dicarboxylic acid component a mainly composed of terephthalic acid and a glycol component b mainly composed of alkylene glycol having 2 to 4 carbon atoms. A glass fiber reinforced polyester resin composition comprising 100 parts by weight of a copolyester containing 0.01 to 8 mol% of oxymonocarboxylic acid component c with respect to component a and (B) 5 to 150 parts by weight of glass fiber.

The dicarboxylic acid component a in the copolymerized polyester (A) of the present invention mainly targets a terephthalic acid component, and a part thereof, that is, less than 10 mol%, is a dicarboxylic acid component other than the terephthalic acid component. It may be replaced.
Examples of the dicarboxylic acid component other than the terephthalic acid component include aromatic dicarboxylic acids such as isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, diphenoxyethane dicarboxylic acid, and diphenyl dicarboxylic acid, and adipic acid and cyclohexane-1. And aliphatic or alicyclic dicarboxylic acids such as 1,4-dicarboxylic acid.

The glycol component b mainly comprising an alkylene glycol having 2 to 4 carbon atoms in the copolymerized polyester of the present invention mainly includes an ethylene glycol component, a tetramethylene glycol component and the like.
Less than mol% may be replaced by another glycol component other than the alkylene glycol component having 2 to 4 carbon atoms. Such other glycol components include hexamethylene glycol, neopentyl glycol, cyclohexane-1,4-
Examples thereof include aliphatic or alicyclic glycols such as dimethanol, and aromatic glycols such as hydroquinone, resorcin, and bisphenols. Furthermore, oxycarboxylic acids such as oxybenzoic acid, oxycaproic acid, and hydroxyethoxybenzoic acid may be copolymerized.

The greatest feature of the present invention is that the polyester contains a dioxymonocarboxylic acid component c having an alkali metal base of a carboxylic acid as a component of the polyester in addition to the two components a and b. The introduction of the polyfunctional component c having an alkali metal base of a carboxylic acid is carried out by reacting an alkali metal salt of dioxymonocarboxylic acid with the dicarboxylic acid component a or the glycol component b or a reaction product thereof, and performing polycondensation. Can be achieved.

Such a polyfunctional component c is a dioxymonocarboxylic acid component having an alkali metal base of a carboxylic acid, and specific examples thereof include an aliphatic, alicyclic or aromatic having 3 or more carbon atoms, preferably 3 to 22 carbon atoms. Alkali metal salts of group dioxymonocarboxylic acids are preferred, most preferred are the alkali metal salts of dimethylolpropionic acid.
Specific examples of the polyfunctional component c other than those described above include, for example, alkali metal salts such as glyceric acid, 4,4-bis (4-hydroxycyclylhexyl) valeric acid, and 9,10-dioxyoctadecanoic acid. .

These dioxymonocarboxylic acids may be substituted with a non-functional substituent such as an alkyl group.

The present invention is not limited to these exemplified components. Examples of the alkali metal salt include a lithium salt, a sodium salt, and a potassium salt, and a sodium salt is particularly preferably used.

The content of the polyfunctional component c in the copolymerized polyester (A) for achieving the object of the present invention is 0.01 to 8 mol%, more preferably 0.1 to 5 mol, based on the dicarboxylic acid component a. %. If the amount is less than 0.01 mol%, the effect of accelerating the crystallization, which is the object of the present invention, is not substantially exerted. On the other hand, if it exceeds 8 mol%, a disadvantage that mechanical properties are deteriorated appears, which is not preferable.

The copolymerized polyester (A) of the present invention is produced by a known method usually used for producing a polyester. First, a reaction is performed by raising the temperature of a mixture of reaction components in the presence or absence of a catalyst, at atmospheric pressure or under pressure, in an inert gas atmosphere. In that case, each raw material component is used in the form of an acid or alcohol or an ester-forming derivative thereof. The temperatures employed to carry out these reactions are in the range from 180 to 270 ° C, preferably in the range from 210 to 260 ° C. After the completion of the reaction, the obtained oligomer product is polycondensed. The polycondensation reaction is carried out in the presence of a compound such as a known polycondensation catalyst such as antimony, germanium, titanium, zinc, cobalt, or manganese at a pressure of 10 mmHg or less, preferably 1 mmHg or less, at a temperature in the range of 270 to 300 ° C. . Where c
The addition of the polyfunctional compound for introducing the components is possible at any stage during the production of the polyester, and may be, for example, at the stage of esterification or transesterification, at the stage of polycondensation, or further added after the polycondensation. The polycondensation may be continued to complete the reaction.

The intrinsic viscosity of the copolymerized polyester (A) of the present invention is 30
When measured in an equal weight mixed solvent system of phenol and tetrachloroethane at a temperature of 0.3 to 1.2, preferably 0.
It is in the range of 4 to 1.0. When the intrinsic viscosity is less than 0.3, the strength physical properties of the polyester are reduced, which is not preferable.
If it is larger, the melt viscosity increases significantly, which causes disadvantages, especially in injection molding.

Copolyester (A) used in the present invention
In the above, the polyfunctional component c is introduced into the polymer molecule by copolymerization. For example, in a copolymerized polyester used in the present invention obtained from terephthalic acid, ethylene glycol and sodium dimethylolpropionate, the polyester is dissolved in a solvent, trifluorinated acetic acid, and 500 MHz ¹
According to the H-NMR spectrum, the absorption of the proton of the methyl group was observed as a singlet at a position of 1.3 ppm in addition to the absorption appearing in PHT, and the copolymerized polyester was dissolved in a solvent (equal weight of phenol and tetrachloroethane). In a sample dissolved in a mixed solvent) and reprecipitated with methanol, the absorption of protons of the methyl group is observed in the same manner (position and intensity), and together with this information, sodium dimethylolpropionate (solvent: In the same spectrum, the absorption of the proton of the methyl group appears at 1.1 ppm, 1.2 ppm and 1.3 ppm, and each peak is Considering that it can be attributed to the structure of the above, it is clear that sodium dimethylolpropionate is introduced into the polymer molecule as a copolymer component, not simply mixed or introduced at the polymer terminal in the polyester. . However, this does not exclude the case where the multifunctional component c is bonded to the terminal in the copolymerized polyester (A) of the present invention.

Since the copolyester (A) of the present invention has the alkali metal base-containing component c, which is considered to act as a crystal nucleating agent, already incorporated in the polymer molecule as a polyester component, the copolyester (A) alone can be sufficiently crystallized. High conversion speed. Therefore, when used as a molding material,
In the conventional PET, it is practically unnecessary to separately add a nucleating agent required for promoting crystallization, and the above-mentioned problems associated with the addition of such a nucleating agent are inevitably solved.

The glass fibers (B) used in the present invention may be ordinary glass fibers used for reinforcing plastics, and preferably have a diameter of 3 to 30 μm. Depending on the production method, various forms of roving or chopped strand can be used. The glass fiber is preferably subjected to a treatment such as a silane treatment or a chromium treatment for the purpose of improving the adhesion to plastics.

Generally, the amount of the glass fiber (B) used is suitably 150 parts by weight or less based on 100 parts by weight of the copolymerized polyester (A). If the amount exceeds 150 parts by weight, the fluidity of the system becomes poor and molding becomes difficult, and the surface gloss of the molded product tends to be impaired.

In the composition of the present invention, when 5 parts by weight or more of the glass fiber is blended, the heat distortion temperature becomes high similarly to the ordinary glass fiber reinforced polyester resin composition. Particularly, in order to obtain a composition having excellent physical properties and a high heat distortion temperature, the glass fiber (B) is preferably used in an amount of 10 to 120 parts by weight based on 100 parts by weight of the copolymerized polyester (A).

In the glass fiber reinforced polyester resin composition of the present invention, a plasticizer may be added as needed in order to further enhance the crystallinity of the polyester molecules at a low temperature. As such a substance, any known substance can be used as long as it functions as described above.

Such examples include, for example, aliphatic esters of polyhydric alcohols, aromatic esters of polyhydric alcohols, esters of polycarboxylic acids, polyalkylene glycols, mono- or dialkyl ethers of polyalkylene glycol, Polyester diols composed of aliphatic glycol and aliphatic dicarboxylic acid, polyester diols obtained by ring-opening polymerization of cyclic esters (lactones), mono- or dialiphatic and / or aromatic carboxylic acid esters of various polyester diols , Aromatic sulfonamides, sodium aromatic sulfonate,
And fluorinated polyolefins.

Among these substances, polyalkylene glycols and mono- or dialkyl ethers of polyalkylene glycol are preferably used.

Among these general formulas _{R 1 OR 2 O n R 1} '...... (I) (R 1, R 1' is H or alkyl having 1 to 10 carbon atoms, acyl, represents aroyl, R ₂ is C2-4 Represents an alkylene group, and n is a number of 5 or more.) In particular, a substance in which R ₁ and R ₁ ′ are a lower alkyl group is preferred. For example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol and their mono or dialkyl ethers (such as monomethyl or dimethyl ether, monoethyl or diethyl ether, monopropyl or dipropyl ether, monobutyl or dibutyl ether, etc.), mono or dialkanoate and mono or Diarene carboxylate (for example, monoacetate, diacetate, mono-2-ethylhexanoate, di-2-ethylhexanoate, monobenzoate, dibenzoate, etc.) can be mentioned. In the present invention, the polyalkylene glycol preferably has an alkyl ether at both ends in that the intrinsic viscosity of the polyester resin at the time of molding is small. When a monoalkyl ether having only one end etherified or a polyalkylene glycol having hydroxyl groups at both ends is used, the intrinsic viscosity of the polyester resin at the time of molding is greatly reduced. It is necessary to use a polyester resin. It is necessary that the degree of polymerization n of the polyalkylene glycol (I) is 5 or more, and if it is less than 5, the polyalkylene glycol (I) tends to emerge on the surface of the molded product, which is not preferable. The amount of the polyalkylene glycol (I) to be used is suitably 10 parts by weight or less, preferably 5 parts by weight or less based on 100 parts by weight of the copolymerized polyester (A). If the amount is more than 10 parts by weight, the rigidity of the molded product decreases, which is not appropriate.

In the glass fiber reinforced polyester fiber composition of the present invention, it is possible to use a crystal nucleating agent in hope of further improving the crystallinity.

In the glass fiber reinforced polyester resin composition of the present invention, a flame retardant can be added as needed.

As the flame retardant used in the present invention, all known flame retardants such as organic halogen type and phosphorus type can be used.

Particularly preferred flame retardants include poly (halogenated styrene), halogenated epoxy compounds and the like.

Further, in the present invention, various flame retardant auxiliaries can be used in combination with the flame retardant. Antimony trioxide, antimony compounds such as sodium antimonate, borates, aluminum hydroxide,
Zirconium oxide or molybdenum oxide is exemplified.

In the glass fiber reinforced polyester resin composition of the present invention, a polymer other than the components described above within a range that does not impair the effects of the present invention, for example, polyester resin, polyolefin resin, acrylic resin, polycarbonate resin, polyamide resin, rubber-like elastic material And the like, and may contain additives commonly used in polyester resins, such as colorants, release agents, antioxidants, and ultraviolet stabilizers.

The glass fiber reinforced polyester resin composition of the present invention,
It is manufactured by mixing each component by any known means.

The composition can be manufactured in any shape by injection molding depending on the shape of the mold.

The molded article of the glass fiber reinforced polyester resin composition of the present invention can be produced not only by injection molding but also by melt molding such as extrusion molding. Molded products obtained by extrusion molding include rods, sheets, plates,
Any shape can be manufactured depending on the shape of the forming die such as a tube or a pipe.

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

 In the present invention, all parts in the examples are on a weight basis.

Synthesis 1-4 dimethyl terephthalate 97 parts, ethylene glycol 68
Parts, manganese acetate (0.024 part) and sodium dimethylolpropionate as a denaturing agent were charged at the respective ratios shown in Table 1 into a reactor equipped with a stirrer, a rectification column and a methanol distillation cooling tube, and then heated from 150 ° C. The mixture was heated to 235 ° C. and subjected to a transesterification reaction while distilling methanol produced by the reaction out of the system.At the time when the distillation of methanol was completed, 0.01 parts of phosphorous acid was used as a stabilizer and 0.034 parts of antimony trioxide was used as a polycondensation catalyst. Parts were added. The obtained reaction mixture was transferred to a reactor equipped with a stirrer and an ethylene glycol distilling condenser, and the temperature of the system was gradually raised from 235 ° C. to 285 ° C. while gradually increasing the system pressure from normal pressure to a high vacuum of 1 mmHg or less. The condensation reaction proceeded while lowering. The polycondensation reaction was terminated when a predetermined melt viscosity was reached. The following evaluation was performed on the obtained polymer, and the results are shown in Table 1.

The intrinsic viscosity ([η]) of the polymer was measured at 30 ° C. using an equal weight mixed solvent system of phenol and tetrachloroethane.

The crystallization rate was evaluated by ΔT obtained by the following method.
ΔT = Tcc−Tch where Tcc and Tch are differential scanning calorimeters (Mettler,
DSC, TA-3000). Tcc indicates the exothermic peak temperature when the sample was put in a calorimeter and melted at 290 ° C. for 5 minutes in a nitrogen stream, and then cooled at a rate of 10 ° C./min. About 50μ with a heated press
FIG. 5 shows the crystallization exothermic peak temperature when the temperature of the substantially amorphous film sample formed into the above film and rapidly cooled with liquid nitrogen was increased at a rate of 10 ° C./min. Regarding the relationship between the crystallization rate and these peak temperatures by DSC, the higher the Tcc and the lower the Tch, the faster the crystallization rate,
Therefore, the larger the value of ΔT, the faster the speed.

The melting point (Tm), which is an index of heat resistance, was expressed as a crystal melting peak obtained when the above-mentioned amorphous film was measured by DSC at a heating rate of 10 ° C./min.

The polymer obtained in Synthesis 3 was dissolved in trifluoroacetic acid and analyzed by 500 MHz ¹ H-NMR.
At the pm position, the absorption of the proton of the methyl group was observed as a singlet. Further, the same NMR analysis was performed on a sample obtained by dissolving the polymer in an equal weight mixed solvent of phenol and tetrachloroethane and reprecipitating with methanol. As a result, it was found that the absorption of the proton of the methyl group was about 1.3 ppm. Observed at intensity.

Synthetic 5-6 PE without adding sodium dimethylolpropionate
Polyester (Synthesis 6) was obtained in the same manner as in Synthesis 1 except that T (synthesis 5) or sodium dimethylolpropionate in an amount (shown in Table 1) out of the range of the present invention as shown in Table 1 was used. The results are shown in Table 1.

Examples 1 to 6 and Comparative Examples 1 to 2 100 parts by weight of the copolymerized polyester obtained by Synthesis 1 to 6 and glass fiber (chopped strand, fiber diameter 9 μm, fiber length 3 mm) shown in Table 2 After being dried and mixed in advance, the mixture was put into a hopper of a 40 mmφ extruder (UT-40-H manufactured by Plastics Engineering Laboratory Co., Ltd.), and the cylinder temperature was 250 ° C.-270 ° C.-275 ° C.-275 ° C.-275 ° C. , Die temperature 285
The mixture was extruded while being melt-kneaded at a temperature of ° C, and the obtained strand was cooled with water and cut with a cutter to obtain a pellet.

After the resulting pellets were dried with hot air at 120 ° C for 15 hours,
Cylinder temperature 240 ℃ -275 ℃ -275 ℃, nozzle temperature 280
A test piece was molded by an injection molding machine (manufactured by Nissei Plastics Co., Ltd., FS 80S 12A SE type) adjusted to a temperature of 120 ° C. and a mold temperature of 120 ° C.

Evaluate the mold releasability at the time of molding and the gloss of the obtained molded product,
The results are shown in Table 2. The physical properties of the obtained test pieces were measured and are shown in Table 2. In addition, it evaluated by the following method.

Releasability The two pieces are 30mm and 25mm long, 10mm deep and 0.5m thick
The ease of mold release when forming a box-shaped molded product of m was evaluated on a five-point scale.

◎ Very good, ○ Good, △ Good, × Bad, ×× Very bad Surface gloss The surface gloss of the flat specimen was measured with a gloss meter (Suga Test Instruments Co., Ltd. UGV-50). Visual evaluation was added, and the evaluation was made according to the following criteria.

 Judgment Glossiness (%) ◎ Very good 70 <○ Good 60-70 △ Good 40-60 × Bad 10-40 ×× Very bad <10 Physical property Evaluation according to the following method Got it.

Tensile strength: ASTM D638 Bending strength: ASTM D790 Flexural modulus: ASTM D790 Izod with notch Impact strength: ASTM D256 Thermal deformation temperature: ASTM D648, load 18.6kg / cm ² Glass fiber reinforced polyester resin composition of the present invention Things are
Molding was performed with good mold releasability during molding, and a molded article with excellent surface gloss was obtained, showing high mechanical strength and excellent heat resistance.

On the other hand, a case using Synthesis 5 (PET) without copolymerizing sodium dimethylolpropionate (Comparative Example 1) and a case using Synthesis 6 using sodium dimethylolpropionate in an amount smaller than the range of the present invention (Comparative Example 1) Example 2)
At this mold temperature, crystallization did not proceed sufficiently, the releasability was very poor, and the resulting molded article was dull. No other performance was evaluated.

Example 7 100 parts by weight of the copolymerized polyester obtained in Synthesis Example 3, 3 parts by weight of polyethylene glycol dimethyl ether (average molecular weight of polyethylene glycol portion: 1,000),
Irganox 1010 (trade name, Ciba-Geigy) 0.3
By weight, 44.3 parts by weight of glass fiber and 44.3 parts by weight of glass fiber were dried and mixed in advance, and a test piece was obtained and evaluated in the same manner as in Example 1. The results are shown in Table 3. The obtained test piece was treated for 7 days with a gear aging tester maintained at 160 ° C., and the degree of coloring was observed.

Comparative Example 3 100 parts by weight of PET obtained by Synthesis 5, 8 parts by weight of sodium salt of ethylene methacrylic acid copolymer (Himilan 1707, manufactured by Mitsui Polychemicals, Inc.), 3 parts by weight of polyethylene glycol dimethyl ether, 10 parts of Irganox 10
10 0.3 parts by weight and 47.7 parts by weight of glass fiber were dried and mixed in advance, and evaluated in the same manner as in Example 7. The results are shown in Table 3.

The glass fiber reinforced polyester resin composition of the present invention,
Crystallization proceeded sufficiently without the addition of a crystal nucleating agent, and molding could be performed with good releasability, and a molded product having excellent surface gloss was obtained. Even after heat treatment, coloring was slight.

On the other hand, a system in which a sodium salt of an ethylene / methacrylic acid copolymer was added as a crystal nucleating agent to PET also had good moldability, but was slightly inferior in rigidity and heat resistance (heat deformation temperature). And showed significant coloration.

[Effects of the Invention] According to the present invention, a glass fiber reinforced polyester resin composition having excellent thermal and mechanical properties and excellent moldability can be obtained.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Keiji Matsumura 1621 Sazu, Kurashiki-shi, Okayama Prefecture Kuraray Co., Ltd. (72) Inventor Tsujishi Kashimura 1621 Sazu, Kurashiki-shi, Okayama Kuraray Co., Ltd. (72) Invention Person Shuhei Ishino 1621 Sazu, Kurashiki-shi, Okayama Prefecture Kuraray Co., Ltd. Examiner Takeshi Sato (56) References JP-A-56-92918 (JP, A)

Claims (2)

(57) [Claims] 1. A polyester comprising (A) a dicarboxylic acid component a mainly composed of terephthalic acid and a glycol component b mainly composed of alkylene glycol having 2 to 4 carbon atoms, wherein a polyester having an alkali metal base of carboxylic acid is used. A glass fiber reinforced polyester resin composition comprising 100 parts by weight of a copolymerized polyester containing 0.01 to 8 mol% of oxymonocarboxylic acid component c based on component a and (B) 5 to 150 parts by weight of glass fiber. 2. The glass fiber reinforced polyester resin according to claim 1, wherein the dioxymonocarboxylic acid component c having an alkali metal base of a carboxylic acid in the copolymerized polyester (A) is an alkali metal salt of dimethylolpropionic acid. Composition.