JPS6347748B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to aromatic polyester compositions. More specifically, the present invention relates to an aromatic polyester composition which has good shape stability of the resin (parison) in a molten state, and has excellent thermal stability and mechanical properties. Aromatic polyester can be manufactured by injection molding, blow molding,
It is processed and put into practical use by various molding methods such as film molding. Among various molding methods,
Particularly when obtaining hollow molded articles by blow molding or when extruding tubes, it is important that the molten polymer (parison) can be held in a constant shape for a sufficient period of time during processing, i.e. in the molten state. It is necessary that the shape stability is good. To this end, as a means of improving the shape stability in the molten state, methods of increasing the molecular weight of the polymer and increasing the melt viscosity are proposed, or as disclosed in JP-A-52-114687 and JP-A-52-80391. A method of increasing the melt strength of polyester by adding a branching agent such as a polyvalent isocyanate or an epoxy compound has been proposed. However, there are two ways to increase the molecular weight of a polymer: one is to increase the molecular weight by melt polymerization, and the other is to obtain a polymer with an intermediate molecular weight by melt polymerization and then polymerize it in a solid phase, but both methods generally have low productivity. is low. Furthermore, in polymers with increased melt strength obtained by adding branching agents such as polyvalent isocyanates or epoxies, it is difficult to obtain the required viscosity level with good reproducibility; However, there are drawbacks such as the tendency to form gelled substances. As a result of intensive studies to improve the shape stability of the aromatic polyester during melting, the present inventors found that the aromatic polyester contains both a copolymer having an epoxy group and a trivalent organic phosphorus compound. The inventors have discovered that the composition has a stable high melt viscosity when melted and satisfies the above object, and has thus arrived at the present invention. That is, in the present invention, an unsaturated monomer having an epoxy group and another unsaturated monomer are copolymerized with 100 parts by weight of an aromatic polyester consisting of an aromatic dicarboxylic acid and a fatty acid diol having 2 to 10 carbon atoms. 1 to 40 parts by weight of copolymer and trivalent organic phosphorus compound
The object of the present invention is to provide an aromatic polyester composition containing 0.1 to 10 parts by weight and having excellent shape stability during melting. The aromatic polyester composed of an aromatic dicarboxylic acid and an aliphatic diol having 2 to 10 carbon atoms used in the present invention is a polyester having an aromatic ring in the chain unit of the polymer.
It is a polymer or copolymer obtained by a condensation reaction using an aliphatic diol having 2 to 10 carbon atoms (or an ester-forming derivative thereof) as the main starting materials. Aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, bis(P-carboxyphenyl)methane, anthracene dicarboxylic acid, 4,4'- These include diphenyl ether dicarboxylic acid or its ester-forming derivatives. In addition, if the acid component is 40 mol% or less, aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, alicyclic dicarboxylic acids such as 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, etc. etc. (such as their ester-forming derivatives) may be substituted with dicarboxylic acids other than aromatic dicarboxylic acids. Examples of aliphatic diols having 2 to 10 carbon atoms include ethylene glycol, propylene glycol, and 1,4-
Butanediol, neopentyl glycol, 1,
These include 5-pentanediol, 1,6-hexanediol, decamethylene glycol, cyclohexanediol, and mixtures thereof. Specific examples of polyesters include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate, and polyethylene-2,6-
Examples include naphthalate. Particularly preferred among these polyesters is polybutylene terephthalate, which has moderate mechanical strength. Additionally, these aromatic polyesters contain 0.5%
The relative viscosity of the orthochlorophenol solution measured at 25°C is preferably in the range of 1.4 to 1.8. The relative viscosity of aromatic polyester is 1.4
If it is less than 1.8, sufficient shape stability during melting cannot be obtained, and if it is 1.8 or more, a molded product with good surface gloss cannot be obtained, and both are undesirable. Epoxy groups constituting a copolymer (hereinafter abbreviated as epoxy group-containing copolymer) consisting of an unsaturated monomer having an epoxy group and at least one other unsaturated monomer used in the present invention What is an unsaturated monomer with the general formula (R is a hydrocarbon group having one ethylenically unsaturated bond.) Unsaturated glycidyl esters represented by the general formula (X is -CH ₂ -O- or

[Formula], and R is the same as the explanation for formula (A). ) or the general formula (R' is hydrogen or a methyl group, and R is the same as the explanation for formula (A).) These include epoxyalkenes and P-glycidylstyrenes, and specifically, acrylic acid Glycidyl, glycidyl methacrylate, itaconate monoglycidyl ester, butenetricarboxylic acid diglycidyl ester, butenetricarboxylic acid triglycidyl ester, 2-methylallyl glycidyl ether, ethylene-P-glycidyl ether, 3,4-epoxybutene, 3,4 ―
Examples include epoxy-3-methyl-1-butene, vinylcyclohexene monoxide, and P-glycidylstyrene. These epoxy group-containing unsaturated monomers can be used in combination of two or more, and the appropriate copolymerization ratio in the epoxy group-containing copolymer is in the range of 1 to 80% by mole weight. In addition, the unsaturated monomers copolymerized with the unsaturated monomer having an epoxy group are ethylene, propylene, butene-1, decene-1, octacene-1,
Olefins such as styrene; vinyl esters containing 2 to 6 carbon atoms in the saturated carboxylic acid component such as vinyl acetate, vinyl propionate, vinyl benzoate; methyl, ethyl, propyl, butyl,
Esters of acrylic and methacrylic acids such as cyclohexyl; maleic anhydride; mono- and di-esters of maleic acid containing 1 to 18 carbon atoms in the saturated alcohol component; acrylonitrile; vinyl ethers; and acrylic acid amides Examples include compounds, and two or more of these can also be used in combination. Among the above, vinyl acetate, acrylic esters, and ethylene are particularly preferably used. In addition, diene monomers such as butadiene and hexadiene, carbon monoxide, and the like may be copolymerized in small amounts. Preferred examples of the epoxy group-containing copolymer in the present invention include ethylene/glycidyl methacrylate copolymer, ethylene/vinyl acetate/glycidyl methacrylate copolymer, ethylene/carbon monoxide/glycidyl methacrylate copolymer, and ethylene/glycidyl methacrylate copolymer. These include glycidyl acrylate copolymer, ethylene/glycidyl acrylate/vinyl acetate copolymer, and ethylene/allyl glycidyl ether copolymer. The amount of the epoxy group-containing copolymer used in the present invention is 1 to 40 parts by weight, preferably 3 to 40 parts by weight, per 100 parts by weight of the aromatic polyester.
It is 30 parts by weight. If the amount added is less than 1 part by weight, the shape stability during melting will not be improved sufficiently, while if it exceeds 40 parts by weight, the properties of the aromatic polyester itself will tend to be impaired, making it difficult to achieve the purpose of the present invention. It becomes difficult. The trivalent organic phosphorus compound, which is another component constituting the composition of the present invention, is represented by the general formula PR ₁ R ₂ R ₃ (D). Here, R ₁ to _{R 3} represent an aliphatic group, an aromatic group, an alicyclic group, an alkoxy group, an alkylthio group, an amino group, or a derivative thereof, and may be the same or different. Also
Two or more of R ₁ R ₂ R ₃ may be connected by any chemical bond. Furthermore, R ₁ to R ₃ may contain a trivalent or pentavalent phosphorus atom. That is,
Two or more phosphorus atoms may be contained in the organic phosphorus compound. R ₁ to _{R 3} are, for example, methyl, ethyl,
Propyl, butyl, octyl, decyl, benzyl, phenyl, tolyl, naphthyl, cyclohexyl, ethoxy, isodekoxy, phenoxy, dimethylamino group, etc., and one of R ₁ to _{R 3} is a halogen atom such as chlorine or bromine. May be replaced. Preferred examples of trivalent organic phosphorus compounds include triphenyl phosphite, triisodecyl phosphite, and tris(nonylphenyl) phosphite. The amount of the trivalent organic phosphorus compound added is 0.05 to 10 parts by weight, preferably 0.1 to 5 parts by weight, per 100 parts by weight of the aromatic polyester. If the amount added is less than 0.05 parts by weight, the shape stability during melting will not be improved sufficiently, while if it is more than 10 parts by weight, it will tend to reduce the melt viscosity, making it difficult to achieve the object of the present invention. be. The composition of the present invention may contain conventional additives such as antioxidants, ultraviolet absorbers, heat stabilizers, lubricants, mold release agents, colorants including dyes and pigments, fibers, etc., to the extent that the object of the present invention is not impaired. They may be modified with solid and particulate fillers and reinforcing agents, nucleating agents, flame retardants, etc. The method of blending the composition of the present invention is not particularly limited, but preferably the aromatic polyester, the epoxy group-containing copolymer, and the trivalent organic phosphorus compound are mixed in an extruder at a temperature higher than the melting point of the aromatic polyester. An example of this method is to melt and knead a homogeneous mixture. The resulting composition is extruded,
It can be molded by any method such as blow molding or injection molding, and the shape stability of the parison is particularly good when used in extrusion molding or blow molding. The present invention will be explained below with reference to Examples, and the properties of the polymers in each Example were measured according to the following methods. Melt viscosity - 250℃ using a high-speed flow tester
Measured at. Melt strength - required to extrude the polymer from the melt indexer at a temperature sufficient to keep the polymer in a molten state (250°C in this example) and extrude 10 cm of the polymer from the bottom of the melt indexer cylinder. The time (T ₁ ) required to extrude 20 cm of the same polymer without interruption is determined. Time and 10 at 20cm
Let T ₂ be the time difference in cm. The melting strength (MS) is determined by the following formula: T ₁ , T ₂
It was calculated as the ratio of MS=T ₁ /T ₂ When the polymer is used for extrusion, approximately 1.0 to approximately
A melt strength of 2.0 is preferred. Ideally, T ₁ and T ₂ should be equal, ie, the melt strength is 1.0, meaning in this case the second 10 cm section was extruded at the same rate as the first 10 cm section. T ₁ for polymers with low melt strength
As a result, T ₂ becomes smaller and smaller, and T ₁ /T ₂ becomes significantly larger than 1.0. In other words, a polymer with a high melting strength is one with a T ₁ /T ₂ ratio close to the ideal value of 1.0, and a polymer with a low melting strength is one with a high
Refers to something with a ratio of T ₁ /T ₂ . Examples 1 to 6, Comparative Examples 1 to 6 The epoxy groups shown in Table 1 were applied to 100 parts by weight of a polyester with a relative viscosity of 1.61 obtained from terephthalic acid as the aromatic dicarboxylic acid and 1,4-butanediol as the diol component. The contained copolymer and trivalent organic phosphorus compound were mixed in the proportions shown in Table 1, and melt-mixed and re-pelletized using a screw extruder set at 250°C. Table 1 shows the melt index and melt strength values of the obtained polymer composition. For comparison, an example in which neither an epoxy group-containing copolymer nor a trivalent organic phosphorus compound was added (Comparative Example 1), an example in which only an epoxy group-containing copolymer was added (Comparative Examples 2 and 3), and a trivalent organic phosphorus compound were added. Examples in which only the organic phosphorus compound was added (Comparative Examples 4 and 5) are also shown.

【table】

[Table] As is clear from Table 1, the presence of both the trivalent phosphorus compound and the epoxy group-containing copolymer makes it possible to obtain an aromatic polyester composition with high melt viscosity and high melt strength. I understand. Examples 7 to 12, Comparative Examples 7 to 12 30% of each of the polymer compositions obtained in Examples 1 to 6
Using a blow molding machine with mmφ screw
A parison having an outer diameter of 22 mm and a wall thickness of 2 mm was molded at 240 to 250°C, and the condition of the parison and the condition of the molded product were evaluated when a 500 c.c. reagent bottle was molded. These results are shown in Table 2. For comparison, the results of similar evaluations of the compositions of Comparative Examples 1 to 6 are also listed.

【table】

[Table] As is clear from Table 2, good blow molded products can be obtained when the aromatic polyester contains an epoxy group-containing copolymer and a trivalent organic phosphorus compound.

Claims (1)

[Claims] 1 A copolymer consisting of an unsaturated monomer having an epoxy group and another unsaturated monomer based on 100 parts by weight of an aromatic polyester consisting of an aromatic dicarboxylic acid and an aliphatic diol having 2 to 10 carbon atoms. An aromatic polyester composition containing 1 to 40 parts by weight and 0.05 to 10 parts by weight of a trivalent organic phosphorus compound.