JPH0364549B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermoplastic polyester composition with excellent impact resistance. Thermoplastic polyesters such as polyethylene terephthalate are widely used as packaging materials for films, sheets, containers, etc. due to their excellent properties such as mechanical strength, rigidity, heat resistance, chemical resistance, and oil resistance. In recent years, these properties have been utilized as engineering plastics to be applied to mechanical parts, electrical appliance parts, automobile parts, etc. However, although thermoplastic polyesters such as polyethylene terephthalate have the above characteristics, they have insufficient impact resistance compared to other engineering plastics, so they are not often used in fields where high impact resistance is required. was the current situation. One way to improve the impact resistance of thermoplastic polyester is to add ethylene to thermoplastic polyester.
Method of adding and mixing propylene rubber, etc. (Tokukosho
No. 46-5225) has been proposed, but the effect of improving impact resistance is insufficient. Furthermore, a method of melt-mixing a thermoplastic polyester with a modified ethylene polymer having a crystallinity of 75% or less, which is grafted with an α,β-unsaturated carboxylic acid or its derivative (Tokuko Showa)
No. 57-54058 and Japanese Patent Publication No. 57-59261) have been proposed, but although this method improves impact resistance, it reduces fluidity and may cause filling defects in injection molded products. Divided. When graft polymerizing α,β-unsaturated carboxylic acid or its derivatives to ethylene polymer with crystallinity of 75% or less in an extruder, α,α′-bis-t-butylperoxy-p - It is necessary to add a peroxide such as diisopropylbenzene as a reaction accelerator, but this also crosslinks the ethylene polymer, resulting in poor fluidity. From this point of view, the present inventors have developed a method that does not impair the appearance and impact resistance of thermoplastic polyester.
As a result of various studies aimed at improving melt fluidity, we have found that the above objective can be achieved by adding a specific ethylene/α-olefin copolymer and an unsaturated carboxylic acid-modified ethylene polymer to thermoplastic polyester. As it turns out, we have arrived at the present invention. That is, the present invention provides thermoplastic polyester (A) 60
an ethylene/α-olefin random copolymer having an ethylene content of 40 to 93 mol%, a crystallinity of 40% or less by X-rays, and a melting point of 40 to 100°C when exhibiting crystallinity. Combined (B) 2 to 39% by weight
and a modified ethylene polymer in which the grafting amount of unsaturated carboxylic acid or its derivative component unit is 0.01 to 3.0 parts by weight based on 100 parts by weight of the base ethylene polymer (D) and the degree of crystallinity by X-rays exceeds at least 75%. A thermoplastic polyester composition comprising 0.1 to 15% by weight of a coalesce (C). The thermoplastic polyester (A) used in the present invention includes ethylene glycol, propylene glycol, 1,
4-butanediol, neopentyl glycol,
Aliphatic glycol such as hexamethylene glycol, alicyclic glycol such as cyclohexanedimethanol, aromatic dihydroxy compound such as bisphenol, or a dihydroxy compound unit selected from two or more of these, and terephthalic acid, isophthalic acid, 2 , aromatic dicarboxylic acids such as 6-naphthalene dicarboxylic acid, aliphatic dicarboxylic acids such as oxalic acid, succinic acid, adipic acid, sebacic acid, undecadicarboxylic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, or these. A polyester formed from dicarboxylic acid units selected from two or more of the following, as long as it exhibits thermoplasticity:
It may be modified with a polyhydroxy compound, polycarboxylic acid, or the like having a higher value than the polyhydric acid. Specifically, these thermoplastic polyesters include polyethylene terephthalate, polybutylene terephthalate,
Examples include polyethylene isophthalate/terephthalate copolymer. The ethylene/α-olefin random copolymer (B) used in the present invention has an ethylene content of 40 to
It is a random copolymer of ethylene and α-olefin having a crystallinity of 93 mol%, preferably 70 to 92 mol%, and a crystallinity measured by X-rays of 40% or less, preferably 30% or less. If the ethylene content is less than 40 mol%, the effect of improving impact resistance, especially at low temperatures, is small, and 93
If the amount exceeds mol%, there is almost no impact resistance improvement effect. If the X-ray crystallinity exceeds 40%, the impact resistance will hardly be improved. In addition, when the ethylene/α-olefin random copolymer (B) exhibits crystallinity, its melting point is usually 40
The temperature ranges from 100℃ to 100℃. Those with a melting point exceeding 100°C tend to have little effect on improving impact resistance. The ethylene content of the ethylene/α-olefin random copolymer (B) in the present invention is ¹³ C-NMR
The melting point is a value measured according to ASTM D3417 using a differential scanning calorimeter (DSC). Further, the ethylene/α-olefin random copolymer (B) used in the present invention usually has a melt flow rate (MFR: ASTM D1238, E) of 0.01 to 50.
The range is g/10min. If the MFR is outside the above range, the moldability and appearance may be poor, and the effect of improving impact resistance may be poor. The ethylene polymer (D) that is the base material of the modified ethylene polymer (C) used in the present invention is a homopolymer of ethylene, ethylene and other α-olefins, or ethylene and vinyl acetate, acrylic ester, vinyl chloride, etc. It is a copolymer with a vinyl compound of
Usually the ethylene content is 95 mol% or more, preferably
It is highly crystalline with a crystallinity of 98 mol% or more and an X-ray crystallinity of more than 75%, preferably 80% or more, and usually has a melt flow rate (MFR; ASTM
D1238, E) is in the range of 0.01 to 50 g/10 min, preferably 5 to 20 g/10 min.
Specifically, the α-olefin copolymerized with ethylene includes propylene, 1-butene, 4
Examples include -methyl-1-pentene, 1-hexene, 1-octene, and 1-decene. The modified ethylene polymer (C) used in the present invention has a grafting amount of unsaturated carboxylic acid or its derivative component unit of 0.01 to 3.0 parts by weight, preferably 0.5 to 3.0 parts by weight, based on 100 parts by weight of the ethylene polymer (D). 2.5
Crystallinity by weight and X-rays is at least 75%
Normal melt flow rate (MFR; ASTM D1238, E), preferably 80 to 85%
is 0.01 to 50g/10min, preferably 5 to 50g/10min.
It is in the range of 20g/10min. Furthermore, the modified ethylene polymer (C) has a molecular weight distribution (w/
n) usually ranges from 3 to 8, preferably from 3 to 7. If the grafting amount of the unsaturated carboxylic acid or its derivative component unit is less than 0.01 part by weight, there will be no compatibility with the polyester, making it impossible to obtain a thermoplastic polyester composition with excellent impact resistance and appearance (lamination delamination occurs). On the other hand, the amount of graft is 3.0
If the amount exceeds 1 part by weight, the degree of crosslinking of the graft modified product will increase, the dispersibility in the thermoplastic polyester (A) will decrease, and the impact resistance and appearance will not be improved. If the crystallinity of the modified ethylene polymer is 75% or less, the rigidity of the thermoplastic polyester composition will decrease, and if the MFR is outside the above range, the moldability of the composition will be poor, and the impact resistance and appearance will deteriorate. etc. may not be improved. Although impact resistance can be improved by using a modified ethylene polymer with a molecular weight distribution exceeding 8, the effect may be small. Examples of the unsaturated carboxylic acid or its derivative component unit of the graft monomer component constituting the modified ethylene polymer (C) include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, and tetrahydrophthalic acid. , methyltetrahydrophthalic acid, endocis-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid (nadic acid), methyl-endocys-bicyclo[2.2.1]hept-5-ene −
Examples include unsaturated carboxylic acids such as 2,3-dicarboxylic acid (methylnadzic acid), and derivatives of unsaturated carboxylic acids such as acid halides, amides, imides, acid anhydrides, and esters of the unsaturated carboxylic acids. Examples include maleyl chloride, maleimide, maleic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate, and glycidyl maleate. Among these, unsaturated dicarboxylic acids or their acid anhydrides are preferred, and maleic acid, nadic acid, and their acid anhydrides are particularly preferred. To produce the modified ethylene polymer (C) by graft copolymerizing the graft monomer selected from the unsaturated carboxylic acids or derivatives thereof to the ethylene polymer (D), various conventionally known methods can be employed. I can do it. For example, there is a method of melting the ethylene polymer (D) and adding a graft monomer to carry out graft copolymerization, or a method of dissolving the ethylene polymer (D) in a solvent and adding a graft monomer to carry out graft copolymerization. In any case, in order to efficiently graft copolymerize the graft monomer, it is preferable to carry out the reaction in the presence of a radical initiator. The grafting reaction is usually carried out at a temperature of 60 to 350°C. The proportion of the radical initiator used is usually in the range of 0.01 to 20 parts by weight per 100 parts by weight of the crystalline ethylene polymer. Examples of the radical initiator include organic peroxides, organic peresters, and azo compounds. The thermoplastic polyester composition of the present invention contains 60 to 97% by weight of the thermoplastic polyester (A), preferably 60 to 89% by weight, and 2 to 39% by weight of the ethylene/α-olefin random copolymer (B). ,
The modified ethylene polymer (C) preferably comprises 10 to 39% by weight and 0.1 to 15% by weight, preferably 1 to 15% by weight. If the amount of the ethylene/α-olefin random copolymer (B) is less than 2% by weight, a thermoplastic polyester composition with excellent impact resistance cannot be obtained, while if it exceeds 39% by weight, the rigidity of the composition will decrease. descend. If the amount of the modified ethylene polymer (C) is less than 0.1% by weight, a composition with excellent impact resistance cannot be obtained, while if it exceeds 15% by weight, only a composition with poor impact resistance can be obtained. In order to obtain the thermoplastic polyester composition of the present invention, the thermoplastic polyester (A), ethylene/α
- A method of mixing the olefin random copolymer (B) and the modified ethylene polymer (C) in the above range using various known methods, such as a Henschel mixer, a V-blender, a ribbon blender, a tumbler blender, etc.; Thereafter, a method may be adopted in which the mixture is melt-kneaded using a single-screw extruder, twin-screw extruder, kneader, Banbury mixer, etc., and then granulated or pulverized. The thermoplastic polyester composition of the present invention includes heat stabilizers, weather stabilizers, antistatic agents, lubricants, slip agents, nucleating agents, pigments or dyes, glass fibers,
Carbon fiber, aromatic polyamide fiber, glass flakes, calcium carbonate, calcium sulfate, talc,
Inorganic or organic reinforcing materials, fillers, etc. such as silica, mica, wollastonite, and potassium titanate fibers may be blended within the range that does not impair the object of the present invention. The thermoplastic polyester composition of the present invention has excellent impact resistance, appearance, and melt flowability compared to conventional compositions that mix ethylene/propylene rubber or compositions that mix modified ethylene polymer, so it can be molded by injection molding. , extrusion molding, compression molding, foam molding, etc. are suitable for applications that require rigidity, heat resistance, and impact resistance, such as automobile parts, electrical appliances, mechanical parts, and industrial parts. Examples will be described below. The measurement method used in the examples of the present invention is as follows. Tensile strength: ASTM D638 Flexural modulus: ASTM D790 Izo impact strength: ASTM D256, notched surface gloss: Visually determined in 3 stages Spiral flow injection molding machine: IS-50 manufactured by Toshiba Machine Co., Ltd. using the following injection pressure The length of the resin injected into the spiral flow test mold is measured under the following conditions: Spiral mold: semicircular connection type R ₁ = 30mm (minimum diameter) Spiral cross-sectional area 9.1mm ^2Mold temperature: 50℃ Injection pressure: 1000Kg/cm ^2Resin temperature: 270℃ Example 1 Polyethylene terephthalate [Product name: Kanebo Bell PETSUTO EFG7, manufactured by Kanebo Gosen Co., Ltd. [η] = 0.78
dl/g; hereinafter abbreviated as PET] 89% by weight, ethylene-propylene random copolymer [ethylene content 80 mol%, X-ray crystallinity 2%, melting point 48
°C, MFR2g/10min; hereinafter abbreviated as EPC] 10% by weight and maleic anhydride-modified ethylene polymer [maleic anhydride grafting amount: base ethylene polymer 100%
2 parts by weight, crystallinity by X-ray 82
%, MFR 4g/10min and w/n5.6; or less
MAH-PE (abbreviated as 1% by weight) was mixed in a Henschel mixer, and then melted and kneaded in a 40 mm diameter single screw extruder set at 270°C to obtain a composition. The obtained pellets were dried under reduced pressure at 130°C for 5 hours, and then the composition was heated to the resin temperature using an IS-50 injection molding machine manufactured by Toshiba Machinery Co., Ltd.
Test pieces were prepared by injection molding at 270°C. The measurement results of physical properties are shown in Table 1. Examples 2 to 3 The same procedure as in Example 1 was carried out except that the blending ratio of the ethylene/propylene random copolymer and the maleic anhydride-modified ethylene polymer was changed. The results are shown in Table 1. Example 4 In Example 2, ethylene-butene-1-random copolymer [ethylene content 91 mol%, crystallinity] was used instead of ethylene-propylene random copolymer.
17%, melting point 72℃ and MFR: 4.0g/10min; or less
The same procedure was carried out except that EBC was used. The results are shown in Table 1. Example 5 The same procedure as in Example 4 was conducted except that the blending ratio of PET and maleic anhydride-modified ethylene polymer was changed. The results are shown in Table 1. Comparative Example 1 The same procedure as in Example 2 was conducted except that the maleic anhydride-modified ethylene polymer was not used in Example 2. The results are shown in Table 1. Comparative Example 2 The same procedure as Example 2 was carried out, except that a modified ethylene/α-olefin copolymer produced by the following method was used instead of the ethylene/propylene random copolymer and the maleic acid-modified ethylene polymer in Example 2. I went in the same way. <Production example of modified ethylene/α-olefin copolymer> Ethylene content 80 mol%, crystallinity 2%,
A mixed solution consisting of 100 parts by weight of an ethylene-propylene random copolymer with an MFR of 1.2, 1.0 parts by weight of acetone, 0.02 parts by weight of α,α'-bis-t-butylperoxy-diisopropylbenzene, and 1.0 parts by weight of maleic anhydride. were mixed dropwise in a Henschel mixer and then granulated at 240°C in a 40mmφ extruder to obtain a maleic anhydride-grafted ethylene/propylene random copolymer with a crystallinity of 2%, an MFR of 0.8, and a graft amount of maleic anhydride of 0.80% by weight. Polymer [hereinafter referred to as MAH
−EPC] was obtained. Example 6 Example 1 except that the blending ratio of the modified ethylene polymer (MAH-PE) was changed.
I went in the same way. Comparative Example 3 The same procedure as in Example 6 was carried out except that a modified ethylene/α-olefin copolymer (MAH-EPC) was used instead of the modified ethylene polymer (MAH-PE).

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Claims (1)

[Claims] 1. Thermoplastic polyester (A) 60 to 97% by weight
and an ethylene/α-olefin random copolymer (B) having an ethylene content of 40 to 93 mol%, a degree of crystallinity measured by X-rays of 40% or less, and a melting point of 40 to 100°C when exhibiting crystallinity. 2 to 39% by weight
and a modified ethylene polymer in which the grafting amount of unsaturated carboxylic acid or its derivative component unit is 0.01 to 3.0 parts by weight based on 100 parts by weight of the base ethylene polymer (D) and the degree of crystallinity by X-rays exceeds at least 75%. A thermoplastic polyester composition comprising 0.1 to 15% by weight of a coalesce (C).