JPS648026B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyethylene terephthalate composition for molding, which can give molded products with good surface gloss and excellent mechanical properties such as impact resistance by injection molding using a relatively low-temperature mold. . Injection molding compositions made of polyethylene terephthalate mixed with glass fibers and fine nucleating agents are known to have excellent mechanical properties such as rigidity and high heat distortion temperatures, and are already used in electrical and electronic parts. Widely used in the field of auto parts. However, injection molded products obtained from polyethylene terephthalate containing glass fibers have a problem in that their appearance including surface gloss is extremely poor, and improvement of this drawback is strongly desired. As a means to improve this problem, injection molding of a polyethylene terephthalate composition is carried out at 120 to 170°C.
Method using a mold (Special Publication Act 18788
However, this method is not only complicated to operate, but also disadvantageous from a thermoeconomic standpoint. Therefore, the present inventors aimed to obtain a glass fiber-containing polyethylene terephthalate composition that has good surface gloss and can give molded products with excellent mechanical properties by injection molding using a mold at 80 to 120°C. As a result of intensive studies, it was discovered that the above object can be effectively achieved by a polyethylene terephthalate composition containing specific amounts of glass fibers having a specific average fiber length, a specific nucleating agent, and a specific nucleating agent.The present invention reached. That is, the present invention has (A) polyethylene terephthalate per 100 parts by weight, (B) a diameter of 5 to 15 μm, and an average fiber length.
Glass fiber of 0.15 to 0.4 mm (However, if the content of glass fiber is 15% by weight or more of the entire composition, the fiber length of 0.4 mm or more in the total composition is less than 15% by weight) glass fiber) from 5 to 100
Parts by weight, (C) Neutral clays, oxides of metals from Group Group of the Periodic Table, silicates, stearates, benzoates, terephthalates, monomethylterephthalic acid of Group Group metals of the Periodic Table 0.1 to 2 parts by weight of at least one compound selected from the group consisting of salts and monomethyl isophthalates, and (D) a montanate of a metal from group ~ of the periodic table or a carbon number of 2
Montanic acid ester salts partially neutralized with ~10 aliphatic diols, higher aliphatic amides with 10 to 40 carbon atoms, dibenzoic acid esters of aliphatic polyols or polyalkylene glycols, higher aliphatic esters with 10 to 40 carbon atoms 0.01 to 5 of at least one compound selected from the group consisting of alcohol and paraffin
The object of the present invention is to provide a polyester composition for molding characterized in that it contains parts by weight. The base polymer component (A) of the composition of the present invention is mainly polyethylene terephthalate.
Copolymerized polyethylene terephthalate containing a small proportion of a dicarboxylic acid component other than terephthalic acid and/or a glycol component other than ethylene glycol can also be used. The dicarboxylic acid components other than terephthalic acid mentioned here include aliphatic dicarboxylic acids having 2 to 20 carbon atoms such as azelaic acid, sebacic acid, adipic acid, and dodecanedicarboxylic acid;
Isophthalic acid, orthophthalic acid, naphthalene dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid,
Aromatic dicarboxylic acids such as diphenylethane-4,4'-dicarboxylic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, β-oxyethoxybenzoic acid, p-oxybenzoic acid, etc., and glycol components other than ethylene glycol is an aliphatic glycol having 3 to 20 carbon atoms, such as propylene glycol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, decamethylene glycol, cyclohexanedimethanol,
cyclohexanediol etc. or molecular weight
400-6000 long chain glycols, such as polyethylene glycol, poly-1,3-propylene glycol, polytetramethylene glycol, and mixtures thereof. In addition, the above polyethylene terephthalate is
The relative viscosity of a 0.5% orthochlorophenol solution measured at 25°C is 1.2-2.0 (intrinsic viscosity 0.36-2.0).
1.39), preferably in the range of 1.3 to 1.8 (intrinsic viscosity 0.52 to 1.18), less than 1.2 (intrinsic viscosity
If it is less than 0.36), sufficient mechanical properties cannot be obtained, and if it exceeds 2.0 (intrinsic viscosity 1.39), a molded product with good surface gloss cannot be obtained, so both are undesirable. The glass fibers (B) present in the composition of the present invention have a diameter of 5 to 15μ and an average fiber length of 0.15 to 0.4
mm. If the average fiber length of the glass fiber is 0.4 mm or more, the surface appearance of the molded product will be impaired.
Further, if the thickness is less than 0.15 mm, not much can be expected from the mechanical properties of the composition. Here, when the glass average fiber length is short, it goes without saying that the smaller the fiber diameter is, the more advantageous it is in terms of mechanical properties. The appropriate content of these glass fibers is 5 to 100 parts by weight per 100 parts by weight of polyethylene terephthalate; if it is less than 5 parts by weight, the effect of improving mechanical properties is insufficient, and if it is more than 100 parts by weight, it will be removed from the composition. This is not preferable because the surface gloss of the molded product will be impaired. Note that the content of glass fiber is
When the content is 15% by weight or more, it is necessary to consider the fiber length distribution of the glass fibers in the composition, and even if the average fiber length is in the range of 0.15 to 0.4 mm, the fiber length If glass fibers of 0.4 mm or more are present in an amount of 15% by weight or more, the appearance of the molded product will be impaired. The glass fibers used in the present invention include commonly commercially available milled fibers with an average fiber length of 0.15 to 0.4 mm, chopped strand type short fibers, and roving type long fibers with an average fiber length of 0.15 to 0.4 mm.
Examples include those cut in advance to fit within the range of . In addition, by using the above chopped strand short fibers as they are and selecting extrusion conditions that cause the glass fibers to be shredded during melt-kneading of the composition, it is possible to have an average fiber length in the final composition in the range of 0.15 to 0.4 mm. It is also possible to disperse it so that The glass fibers to be used are pre-prepared with ordinary coupling agents such as silane, alkoxysilane, epoxysilane, and titanium, and binding agents such as polyvinyl acetate, polyvinyl alcohol, epoxy resin, and ethylene-acrylic acid copolymer. It may be a processed one. The component (C) contained in the composition of the present invention is a so-called nucleating agent that acts as a crystal nucleating agent, and basically has the function of increasing the crystallization temperature of polyethylene terephthalate and increasing the crystallization rate.
Specific examples of component (C) include talc, magnesium oxide, zinc oxide, magnesium silicate, sodium stearate, barium stearate, potassium benzoate, sodium terephthalate, sodium monomethyl terephthalate, sodium monomethyl isophthalate, etc. . The content of these components (C) is 0.1 to 2 parts by weight, especially 0.3 to 1.0 parts by weight, per 100 parts by weight of polyethylene terephthalate, and if it is less than 0.1 part by weight, it has almost no function as a practical crystal nucleating agent. If it exceeds 2 parts by weight, the properties of polyethylene terephthalate will be impaired, which is not preferable. The above component (D) contained in the composition of the present invention acts synergistically with the above component (C) as a lubricant to improve the crystallization rate of polyethylene terephthalate,
By widening the crystallization temperature range, it functions to speed up crystallization when using a low-temperature mold. In addition, component (D) exhibits an effective action as a mold release agent during molding. Specific examples of component (D) include montanic acid and a montanate salt made of a metal such as lithium, sodium, potassium, magnesium, calcium, or aluminum; a montanate salt made of ethylene glycol, 1,2- or 1,3-propanediol , montanic acid ester salts consisting of a montanic acid ester partially neutralized with an aliphatic diol such as 1,3- or 1,4-butanediol and the above metals, stearic acid amide, palmitic acid amide,
Higher fatty acid amides such as methylene bis stearamide and ethylene bis stearamide, dibenzoic acid esters of aliphatic polyols such as ethylene glycol, triethylene glycol, neopentyl glycol, pentaerythritol, and polyethylene glycol, cetyl alcohol, stearyl alcohol, etc. higher aliphatic alcohols and paraffins. The content of these components (D) is 0.01 to 100 parts by weight of polyethylene terephthalate.
5 parts by weight, especially 0.3 to 3 parts by weight; if it is less than 0.01 part by weight, it will not be possible to obtain a molded product with good surface gloss using a low-temperature mold, and if it is more than 5 parts by weight, the properties of polyethylene terephthalate will be impaired. This is not desirable because it causes In the composition of the present invention, the base polymer (A) component is (B)
It is important to contain the three components (D) to (D) as essential components; for example, if either (C) or (D) is missing, the desired effect cannot be obtained.
In other words, in order to obtain a composition with excellent surface gloss from a composition consisting of two components (A) and (B), 120%
Although it is necessary to use a high-temperature mold above ℃,
By using (C) and (D) together with this, 120℃
Hereinafter, it becomes possible to obtain a molded product with excellent surface gloss using a low-temperature mold of, for example, 80 to 120°C.
However, in this case, it is essential to contain both (C) and (D), and the absence of either of them is not preferable because the mold temperature for obtaining a molded product with excellent surface gloss becomes high. Also, the average fiber length of component (B) is
If it is 0.4 mm or more, it is impossible to obtain a molded product with good surface gloss using a low-temperature mold, even if (C) and (D) are used together. The means for preparing the composition of the present invention is not particularly limited, but if glass fibers of 0.4 mm or more are used, conditions must be selected so that the glass fibers are shredded during melt-mixing as described above. A preferred method is to preliminarily measure and blend the above components (A) to (D), feed this into an extruder equipped with a specific screw, melt and knead it, cool the resulting guts, and cut them into chips. There are several methods. The composition of the present invention may contain antioxidants and heat stabilizers (for example, hindered phenols typified by Ciba Geigy's Irganox 1010, hydroquinone, thioethers, phosphites, and substituted products thereof. UV absorbers (e.g. various resorcinols, salicylates, benzotriazoles, benzophenones, etc.), dyes (e.g. nitrosine) and pigments (e.g. cadmium sulfide, phthalocyanines, carbon black, etc.); flame retardants; (e.g. decabromodiphenyl ether, halogen-based such as brominated polycarbonate, melamine or cyanuric acid-based, phosphorus-based, etc.), flame retardant aids (e.g. antimony oxide, etc.), antistatic agents (e.g. sodium dodecylbenzenesulfonate, Other additives such as polyalkylene glycols, etc.) may also be included. Polyethylene terephthalate can also be used in small amounts with other thermoplastic resins (e.g. polyethylene, polypropylene, acrylic resins, fluorine resins, polyamides, polyacetals, polycarbonates, polysulfones, polyphenylene oxides, etc.), thermosetting resins (e.g. phenolic resins, melamine resins, etc.). , polyester resins, silicone resins, epoxy resins, etc.), soft thermoplastic resins (e.g. ethylene/vinyl acetate copolymers, polyester elastomers,
It may also be a blend of ethylene/propylene terpolymers, etc.). The composition of the present invention exhibits excellent effects particularly when applied to injection molding, but can also be applied to extrusion molding, compression molding, and the like. The effects of the present invention will be explained below with reference to Examples. Example 1 For 100 parts by weight of polyethylene terephthalate with a relative viscosity of 1.35 (intrinsic viscosity 0.60), a diameter of 10μ,
45 parts by weight of milled fiber with an average fiber length of 0.3 mm;
In addition, various additives shown in Table 1 are used as crystal nucleating agents.
0.7 parts by weight and 1 part by weight of various additives shown in Table 1 as lubricants were mixed, melt-blended and cooled into pellets using an extruder equipped with a screw of 65 mm diameter at a cylinder temperature of 280°C. The length of glass fibers was measured by appropriately sampling the pellets, dissolving them in θ-chlorophenol, and performing microscopic observation. The obtained pellets were dried at 130°C for 4 hours, and then molded into 80mm x 80mm squares with a thickness of 1mm and 3mm using an injection molding machine with a 5-ounce injection capacity at a cylinder temperature of 280°C and a mold temperature of 1mm and 3mm. A plate was molded and the degree of surface gloss and moldability were observed. It can be seen that the compositions according to the present invention (Nos. 7 to 26) have excellent surface gloss of molded products even at lower mold temperatures.

【table】

[Table] Example 2, Comparative Example 3 100 parts by weight of polyethylene terephthalate similar to that used in Example 1 and chopped strand type glass fiber with a diameter of 13 μm and an average fiber length of 3 mm or a chopped strand type glass fiber with a diameter of 10 μm and an average fiber length of 0.3 mm. 45 parts by weight of milled fiber and various additives shown in Table 2 were melt-mixed in the same manner as in Example 1, and pelletized. The obtained pellets were dried at 130°C for 4 hours, and
Using an injection molding machine with an injection capacity of 1.5 oz., a 1/2" width Izot impact test (based on ASTM D256) was conducted at a cylinder temperature of 280°C and a mold temperature of 110°C to evaluate the mechanical properties. It is shown in Table 2.

【table】

Claims (1)

[Scope of Claims] 1 (A) Per 100 parts by weight of polyethylene terephthalate, (B) Glass fibers with a diameter of 5 to 15 μm and an average fiber length of 0.15 to 0.4 mm (provided that the content of glass fibers is 15 parts by weight of the entire composition) (C) Neutral clays, periodic table oxides of group metals,
At least one compound selected from the group consisting of silicates, stearates, benzoates, terephthalates, monomethyl terephthalates, and monomethyl isophthalates of Group 3 metals of the periodic table, in an amount of 0.1 to 2 parts by weight and (D) a montanate salt of a metal from group ~ of the periodic table or a montanic acid ester salt partially neutralized with an aliphatic diol having 2 to 10 carbon atoms, a higher fatty acid amide having 10 to 40 carbon atoms, and a fat. A molding characterized by containing 0.01 to 5 parts by weight of at least one compound selected from the group consisting of a dibenzoic acid ester of a group polyol or a polyalkylene glycol, a higher aliphatic alcohol having 10 to 40 carbon atoms, and paraffin. Polyester composition for use.