JPS6357466B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a reinforced polyethylene terephthalate composition with excellent moldability, physical properties, and appearance of molded products. Since polyethylene terephthalate has a slow crystallization rate at low temperatures, there is a limit to the degree of crystallinity that can be achieved using conventional molding methods, and it has the disadvantage that only products with poor moldability and physical properties can be obtained. On the other hand, it is known that moldability and physical properties can be improved by adding an inorganic filler such as glass fiber to increase rigidity, but this alone does not provide sufficiently satisfactory physical properties. In particular, the dependence of heat resistance on the degree of crystallinity is large, and the heat distortion temperature of polyethylene terephthalate molded in a mold with a secondary transition point of about 80°C or lower in the amorphous state is 80 to 90°C. When molded in a mold with a crystallization initiation temperature of about 120°C or higher, the heat distortion temperature approaches 200°C, and the effect of glass fiber filling becomes noticeable. Therefore, if heat resistance is required for reinforced polyethylene terephthalate, it is necessary to mold it in a mold at a high temperature of 140 to 150°C, which is a major drawback in molding processing. In this regard, the addition of a crystal nucleating agent is effective, as it increases the crystallization rate and degree of crystallization, resulting in a mold that exhibits a fairly high heat distortion temperature even at low temperatures, and has various nucleating effects. compounds have been reported. For example, according to Japanese Patent Publication No. 44-7542, carbon powder, neutral clays, divalent metal oxides, or benzoates are effective.
According to Special Publication No. 45-9470, CaCO ₃ , Sb ₂ O ₃
and glass powder. Although it is true that the heat resistance is improved by adding these, it does not completely eliminate mold temperature dependence and is not fully satisfactory. As a result of intensive research into more effective nucleating agents, the present inventors discovered that glass foil has a remarkable effect of promoting crystallization.
At this time, it was discovered that the physical properties could be further improved by adding a reactant in which an epoxy compound having a triazine ring and an aromatic carboxylic acid or its acid anhydride were reacted in a specific ratio, and the present invention was completed. That is, in the present invention, 0.5 to 2 of the aromatic carboxylic acid or its acid anhydride is added to 1 mole of the epoxy compound having polyethylene terephthalate and a triazine ring.
0.05 to 5% by weight of the reactant obtained by reacting the mole with respect to polyethylene terephthalate and in the total composition.
10-50% by weight fibrous reinforcing filler and 1-40% by weight
The present invention relates to a reinforced polyethylene terephthalate composition characterized by comprising a glass foil. Although it is known that adding an epoxy resin to reinforced polyethylene terephthalate improves its physical properties and moldability, the epoxy resins that have been used so far do not necessarily show satisfactory effects and cannot be said to be sufficient. Commonly used epoxy resins include bisphenol type such as diglycidyl ether of bisphenol A, polyol ether type, and polyhydric carboxylic acid ester type, but when these are added to reinforced polyethylene terephthalate, uniform In some cases, the physical properties do not improve, and some actually cause a decrease in strength. Although bisphenol type epoxy compounds show a comparative effect of improving physical properties, the effects are not necessarily high and remain at a low level overall. On the other hand, epoxy compounds having a triazine ring bring about extremely significant improvement in mechanical properties and exhibit a particularly large effect. However, when an epoxy compound having a triazine ring is added alone to reinforced polyethylene terephthalate, there are disadvantages in that the fluidity becomes poor and moldability decreases, and coloration occurs during molding, impairing the appearance and lowering the commercial value. This drawback is
This problem can be solved by using a reactant made by reacting an epoxy compound with a triazine ring with an aromatic carboxylic acid or its acid anhydride in a specific ratio, which has high physical properties and does not cause a decrease in fluidity or coloring of molded products. A molded product with a good appearance can be obtained. However, even in this case, it has not been possible to improve the mold temperature dependence of heat resistance, among other physical properties, and only a low heat distortion temperature can be obtained when molding with a low temperature mold of 100°C or less. . On the other hand, products containing glass foil exhibit a high heat distortion temperature of over 200°C even when molded in a low-temperature mold of 100°C or less, and are almost comparable to those molded in a high-temperature mold. Become. In addition, the molded product is homogeneous and opaque, and in particular, silver streaks on the surface are improved, and the product has excellent smoothness and gloss. Furthermore, since glass foil itself has a reinforcing effect, the physical properties are generally maintained even if a portion of the fibrous reinforcing filler used is replaced with glass foil. These points are extremely advantageous points of glass foil, and are characteristics not found in other nucleating agents. Nucleating agents other than glass foil, such as divalent metal oxides and benzoates, do not particularly improve the smoothness and gloss of the molded product and do not have any reinforcing effect on their own. Further, even glass powder having a relatively similar composition has a lower reinforcing effect than glass foil, and in particular, its crystallization promoting effect is significantly inferior to that of glass foil. If other fillers such as CaCO ₃ and Al ₂ O ₃ that are commonly used as fillers are added to reinforced polyethylene terephthalate, the strength will be significantly lowered and the nucleating agent effect will be much smaller than that of glass foil. The polyethylene terephthalate used in the present invention is a linear polyester having ethylene terephthalate units as a main constituent unit or a thermoplastic composition having the polyester as a main component, and the degree of condensation thereof is not particularly limited. As the fibrous reinforcing filler used in the present invention, in addition to commonly used glass fibers, any fibrous inorganic material such as carbon fiber, asbestos fiber, titanate fiber, etc. can be used. The amount added is 10~
A range of 50% by weight is preferable; if it is less than 10% by weight, the physical properties will be poor, and if it exceeds 50% by weight, the fluidity during molding will be reduced, which is unsuitable. The glass foil used in the present invention is a scale-like flake with a thickness of 0.5 to 10 μm and 32 meshes or less. The effects of the present invention cannot be obtained with powder or milled fiber obtained by pulverizing glass. The amount added is preferably 1 to 40% by weight; if it is less than 1% by weight, the nucleating agent effect is low and high heat resistance cannot be obtained, and if it exceeds 40% by weight, it becomes brittle and the physical properties deteriorate, so it is inappropriate. . Further, the epoxy compound having a triazine ring used in the present invention has two or more epoxy groups, and specifically includes triglycidyl isocyanurate (TGIC), triglycidyl cyanurate, N-methyl-N', Examples include N″-diglycidyl isocyanurate (DGIC).
The aromatic carboxylic acids to be reacted include benzoic acid,
Examples include toluic acid, dimethylbenzoic acid, ethylbenzoic acid, phthalic acid, and acid anhydrides thereof, and among these, benzoic acid is preferred. The reaction conditions for the epoxy compound and aromatic carboxylic acid are preferably melting and stirring at 100 to 200°C for 5 to 30 minutes. When the reaction temperature is lower than 100°C, the reaction becomes non-uniform and requires a long reaction time. or
If the temperature is higher than 200°C, the reaction product will be colored, which is inappropriate. When the reactant is viscous and difficult to add and mix, it may be diluted with an appropriate inert solvent such as tetrachloroethane, chloroform, acetone, etc. before addition. The amount of the reactant added is in the range of 0.05 to 5% by weight based on polyethylene terephthalate, and the molar ratio of the epoxy compound and aromatic carboxylic acid is
It is important that the reaction is carried out at a concentration of 0.5 to 2. If the amount of the reactant added is less than 0.05% by weight, the effect of improving the physical properties will be low, and if it exceeds 5% by weight, the mechanical strength will not be improved and fluidity will deteriorate, which is unsuitable. In addition, if the molar ratio of the aromatic carboxylic acid to the epoxy compound is less than 0.5, fluidity will decrease and the molded product will be colored, while if it exceeds 2, the effect of improving physical properties, especially mechanical strength, will decrease, which is undesirable. . Epoxy compounds and aromatic carboxylic acids that have a triazine ring are generally in powder form, but by reacting them, they become a sticky liquid. When added to terephthalate and mixed, the filler adheres to polyethylene terephthalate via the reactant, improving mixing and dispersibility, and advantageously, there is no scattering of the filler during mixing and kneading operations. In addition, a system in which an epoxy compound and an aromatic carboxylic acid are added as reactants has good dispersibility of the fibrous reinforcing filler and glass foil, has high physical properties, and has a good appearance, smoothness, and gloss. The method for mixing the polyethylene terephthalate, the reaction product of an epoxy compound and an aromatic carboxylic acid or its acid anhydride, the fibrous reinforcing filler, and the glass foil constituting the reinforced polyethylene terephthalate composition of the present invention is by batch melt-kneading or polyethylene terephthalate. Either method may be used, in which a fibrous reinforcing filler and glass foil are further added to the modified polyethylene terephthalate obtained by melt-kneading a mixture of the above-mentioned reactants, but the latter method yields a product with higher physical properties. It will be done. Although any commonly used melt-kneading apparatus can be used in carrying out the present invention, an extruder is particularly preferred from the viewpoint of process simplicity. Appropriate extrusion conditions are 265-300°C and an average residence time of 2-10 minutes. The present invention will be explained in more detail with reference to Examples below. Example 1 50 parts of TGIC and 20 parts of benzoic acid were placed in a 4-necked separate flask and heated at 120°C under a nitrogen atmosphere.
The reaction was carried out by melting and stirring for 30 minutes to obtain a viscous liquid. 14 parts of this reaction product was diluted with 30 parts of acetone, added to 2000 parts of polyethylene terephthalate ([η]=0.72), mixed in a tumbler, and then dried for 1 hour in a steam dryer at 80°C to remove acetone. The resulting polyethylene terephthalate chips had a uniform coating of the reactant on the surface and were somewhat sticky. To this, 712 parts of 3mm glass chopped strands and 145 parts of glass foil (200 mesh or less, thickness 3μ) were added and mixed in a tumbler. The glass fibers and glass foil adhered uniformly to the chips, resulting in less scattering. A mixture was obtained. This is L/D
Pellets were obtained by extrusion at 280° C. using a 30 mmφ extruder of 25 mm. The cylinder temperature is 280℃ using a 5oz 36mmφ screw in-line injection molding machine.
A 3.2 mm thick No. 1 dumbbell, a 3.2 mm thick thermally deformed specimen, and a 6.4 mm thick thermally deformed specimen were made by injection molding at a mold temperature of 80°C, and their physical properties were evaluated. Tensile strength is determined by ASTM D638 from a No. 1 dumbbell, and heat distortion temperature (HDT) is determined by ASTM D790 from a 6.4 mm thick heat deformed specimen.
It was measured by For comparison, various epoxy compounds were mixed in a tumbler instead of the above reactants, and the molding was evaluated in the same manner. The results are shown in Table 1. Among epoxy compounds, epoxy compounds with triazine rings, such as TGIC and DGIC, exhibit significantly high tensile strength. However, the disadvantage is that the gauge pressure of the shot is high, resulting in poor moldability and coloring of the molded product. On the other hand, compositions using the reactants of the present invention have high physical strength, low shot shot gauge pressure, good moldability, and produce molded products with excellent appearance and no coloration. Furthermore, despite the mold temperature being 80°C, HDT uniformly shows a high value of 200°C or more by adding glass foil, regardless of the type of epoxy compound.

【table】

[Table] Example 2 0.7 parts of a reactant of TGIC and benzoic acid (molar ratio 1) was added to 70 parts of the same polyethylene terephthalate used in Example 1, and a glass chopped strand of 3 mm was added. The various nucleating agents shown above were added and mixed, and pellets were extruded at 280°C using a 30 mmφ non-vent extruder with L/D=25. This was molded using a 5 ounce, 36 mmφ screw in-line injection molding machine with a cylinder temperature of 280°C and varying mold temperatures, and the physical properties were evaluated according to Example 1. The results are shown in Table-2. When molded in a low-temperature mold at 80°C, calcium benzoate and magnesium stearate exhibit heat distortion temperatures of 200°C or higher when using nucleating agents other than glass foil.
Others are as low as 85-107°C, showing only a small effect compared to 87°C with no nucleating agent added. Also, in the case of calcium benzoate and magnesium stearate, the dependence on mold temperature is greater than that of glass foil, and a difference in heat distortion temperature of nearly 15 to 20 degrees Celsius is observed between an 80 degrees Celsius mold and a 150 degrees Celsius mold. On the other hand, glass foil has a low temperature of 0 to 10°C. CaCO ₃ , Al ₂ O ₃ , glass powder, etc. have low thermal deformation temperatures in low-temperature molds and have reduced tensile strength.
It cannot be said to be an effective nucleating agent. Note that with nucleating agents other than glass foil, the gloss of the molded product is generally inferior, and although it is considerably improved by raising the temperature of the mold, it is not as effective as adding glass foil. Among glass foils, the smaller the particle size, the better both the tensile strength and heat distortion temperature, but the values are uniformly high. Furthermore, even when a portion of the chopped strands was replaced with glass foil, almost no significant difference was observed in the physical properties, indicating that the glass foil itself has a reinforcing effect. However, if the amount of glass foil is less than 1% by weight, the heat deformation temperature will drop significantly, which is unsuitable. The molded product obtained from only 70 parts of polyethylene terephthalate and 30 parts of glass chopped strand has a tensile strength of 1620 kg/
cm ² and heat distortion temperature of 87°C.

[Table] Note) Gloss is judged by the naked eye: ◎ Particularly good ○ Good △
Somewhat poor × Bad Example 3 The reactants were prepared in the same manner as in Example 1 except for changing the type and quantitative ratio of the reactants, and the glass chopped strands and glass used in Example 1 were coated on polyethylene terephthalate. Foil Example 1
Table 3 shows the results of extrusion and injection molding by adding the same amount of the same amount as the above and examining the physical properties of the molded product. The appropriate molar ratio of TGIC and benzoic acid is in the range of 0.5 to 2, and the amount of reactants added is 0.05 to 5% by weight.
If it deviates from these ranges, the appearance, fluidity, strength, etc. will deteriorate, which is not preferable. (N-Methyl-N′,N″-diglycidyl isocyanurate) Coloring of molded products ◎ Not at all ○ Slightly △ Quite × Significantly

[Table] Example 4 Reactant 14 of TGIC and benzoic acid used in Example 1
1 part was added to 2000 parts of polyethylene terephthalate chips with [η] = 0.72, mixed in a tumbler, and then extruded at 280°C using a 30 mmφ extruder with L/D = 25. Example 1 After adding and mixing 375 parts of 3 mm chopped strands and 75 parts of glass foil (200 mesh or less, thickness 3 μm) to 1050 parts of the obtained modified polyethylene terephthalate pellets and extruding them using the same extruder. Injection molding was performed in the same manner as above, and the physical properties were evaluated. The molded product has good gloss with no coloration, has a tensile strength of 1820Kg/cm ² , a high heat distortion temperature of 235℃, and a shot shot gauge pressure of 18Kg/cm 2 .
The moldability was also good at ^cm2 .

Claims (1)

[Claims] 1 A reaction product obtained by reacting 0.5 to 2 moles of an aromatic carboxylic acid or its acid anhydride to 1 mole of polyethylene terephthalate and an epoxy compound having a triazine ring is added to the polyethylene terephthalate in an amount of 0.05 to 5% by weight and based on the total composition. 10-50% by weight
A reinforced polyethylene terephthalate composition comprising a fibrous reinforcing filler and 1 to 40% by weight of glass foil.