JPH08283549A - Thermoplastic polyester resin composition and sheet - Google Patents

Abstract

PURPOSE: To obtain a thermoplastic polyester resin compsn. which crystallizes quickly, can be molded in a short cycle time, and has a high heat resistance by compounding a specific crystalline polyester resin, a specific carboxylic-acid modified polyolefin, and a low-crystalline polyolefin. CONSTITUTION: This compsn. comprises 60-90 pts.wt. crystalline polyester resin which is produced from a dicarboxylic acid component contg. 80mol% or higher terephthalic acid and a diol component contg. 80mol% or higher ethylene glycol and has an intrinsic viscosity of 0.5-1.5dl/g; 0.5-20 pts.wt. carboxylic-acid- modified polyolefin having a melt flow rate of 0.1-100g/10min; and 0.5-20 pts.wt. low-crystalline polyolefin having a melt flow rate of 0.1-100g/10min. The compsn. crystallizes quickly, can be molded in a short cycle time, is excellent in heat resistance, cold resistance, impact strength, thermal stability, etc., and is suitable for a container used for heating food.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin composition having excellent heat resistance, heat stability, cold resistance, impact resistance, aroma retention, moldability and the like. More specifically, the present invention relates to a polyester resin composition and a sheet that have a high crystallization rate, can be molded in a short molding cycle, and have excellent heat resistance and that are suitable for a container used when heating food.

[0002]

2. Description of the Related Art Generally, polyester, polystyrene, polypropylene, etc. are used as a resin container for foods. Particularly, polyester resin is excellent in aroma retention, gas barrier property, transparency, hygiene, etc. It is widely used not only for containers but also for beverage bottles.

With the recent widespread use of various household cooking appliances, frozen foods that are heated using a microwave oven or a convection oven have become widespread.
It is said that the heat resistance is required to be 130 ° C. or higher for microwave ovens and 200 ° C. for heat convection ovens.

Since thermoplastic polyester has a high melting point, it is generally known that when it is crystallized, its practical heat resistance is improved depending on its crystallinity. Particularly, among the thermoplastic polyesters, crystallized polyethylene terephthalate is used. It is often introduced to use as a heating container. However, since polyethylene terephthalate has a slow crystallization rate, in order to obtain a molded product with good dimensional stability and high crystallinity, hold it in a high temperature mold for a long time during injection molding or thermoforming. There was a need. Therefore, when molding polyethylene terephthalate and its copolymer as a heat-resistant container, a drawback is that the molding cycle is long.

In order to accelerate the crystallization of these polyethylene terephthalates and the like, attempts have been made to add various crystallization accelerators, and α-olefin / maleic anhydride as disclosed in JP-A-56-103237. Addition of copolymer, addition of functional group-containing hydrocarbon polymer as disclosed in JP-A-55-161843, JP-B-45-262.
An improved method such as addition of an ionic copolymer as disclosed in Japanese Patent No. 25 is introduced. On the other hand, since polyethylene terephthalate whose crystallinity is improved by these methods has a low impact resistance particularly at low temperatures, when containing foods in a frozen state, problems such as drop strength of the container occur.

As a method for improving the impact resistance of thermoplastic polyester, the addition of various impact modifiers has been studied,
Addition of an alicyclic carboxylic acid-modified olefin elastomer as described in JP-A-58-38747, JP-A-55-
The addition of polyether and olefinic elastomers such as JP-A-86835 and the addition of acrylate-diene copolymers such as JP-B-45-22624 are introduced. However, the effect of improving the shortening of the molding cycle and the improvement of heat resistance has not been sufficiently observed only by adding these. Further, when the above-mentioned crystallization accelerator and impact modifier are used in combination, mutual affinity is poor, and thus sufficient improvement effect is not observed.

Regarding the heating container for food, a resin material usable for both a microwave oven and an oven is also introduced. Actually, the microwave oven mainly reheats the cooked food and the oven mainly heats and cooks at high temperature for a long time, and the two have different conditions such as cooking temperature and time. For this reason, especially for containers used only for microwave ovens, molding is performed to make the containers usable in both microwave ovens and heat convection ovens, although they do not require heat resistance as high as containers for heat convection ovens. The cycle, cost, etc. are hindered.

[0008]

Therefore, as a resin particularly used for a container for a microwave oven, it crystallizes rapidly in a heating mold when molding the container, and practical heat resistance after crystallization is 130 ° C. or more. Therefore, it is necessary that the low temperature impact resistance is good.

[0009]

Means for Solving the Problems As a result of intensive studies for achieving the above object, the present inventors have found that a polyester prepared by co-adding a specific carboxylic acid-modified polyolefin and a low crystalline polyolefin to a thermoplastic polyester. We have found that the resin composition is excellent in heat resistance, low temperature impact resistance, and crystallization rate, and reached the present invention.

That is, the gist of the present invention is that (A) 80 mol% or more of the dicarboxylic acid component is terephthalic acid and 80 mol% or more of the diol component is ethylene glycol.
60 to 99 parts by weight of a crystalline polyester resin having an intrinsic viscosity of 0.5 to 1.5 dl / g, and (B) a carboxylic acid-modified polyolefin having a melt flow rate of 0.1 to 100 g / 10 min. And a thermoplastic polyester resin composition comprising (C) 0.5 to 20 parts by weight of (C) a low crystalline polyolefin having a melt flow rate of 0.1 to 100 g / 10 minutes.

The present invention will be described in detail below. The crystalline polyester resin (A) used in the resin composition of the present invention is
A polyester having terephthalic acid and ethylene glycol as main repeating units, wherein 80 mol% or more, preferably 90 mol% or more, more preferably 95 mol% or more of the dicarboxylic acid component is terephthalic acid, and 80 mol% of the diol component. Mol% or more, preferably 90 mol% or more,
More preferably, 95 mol% or more is ethylene glycol. When a dicarboxylic acid component other than terephthalic acid is used in an amount exceeding 20 mol% of the dicarboxylic acid component and when a diol component other than ethylene glycol is used in an amount exceeding 20 mol% of the diol component, the crystallinity of the polyethylene terephthalate chain is reduced. However, it is not preferable because it is inferior in heat resistance.

The total content of the dicarboxylic acid content other than terephthalic acid in the dicarboxylic acid component and the diol content other than ethylene glycol in the diol component is usually 30 mol% or less, preferably 20 mol% or less,
More preferably, it is 10 mol% or less. When these copolymerization components are used in an amount of more than 30 mol%, the crystallinity of the polyethylene terephthalate chain is lowered and the heat resistance is poor, which is not preferable.

The dicarboxylic acid which can be used as a copolymerization component within a range not exceeding 20 mol% of the dicarboxylic acid component includes isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid,
Examples thereof include 1,4-cyclohexanedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, succinic acid, adipic acid, sebacic acid and the like. Of these, 1,4-cyclohexanedicarboxylic acid and 2,6 are preferred.
-Naphthalenedicarboxylic acid, isophthalic acid. Further, in the present invention, an oxycarboxylic acid component such as hydroxybenzoic acid and glycolic acid, a trifunctional or higher functional carboxylic acid component such as trimellitic acid, trimesic acid and pyromellitic acid, etc., in an addition amount within a range that does not impair the performance thereof. Can also be treated as a dicarboxylic acid component and replaced.

As the diol which can be used as a copolymerization component within a range not exceeding 20 mol% of the diol component, 1,4-cyclohexanedimethanol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,6- Hexamethylene glycol, neopentyl glycol and the like can be mentioned. Of these, 1,4-cyclohexanedimethanol, diethylene glycol and 1,4-butanediol are preferable. Further, in the present invention, the addition amount of the range that does not impair the performance, trimethylolethane, trimethylolpropane,
A trifunctional or higher functional hydroxy component such as pentaerythritol or glycerin, or a polyalkylene glycol having a number average molecular weight of 100 to 10000 such as polyethylene glycol, polypropylene glycol or polytetramethylene glycol can be treated and substituted as the diol component.

When diethylene glycol is used as a copolymerization component, diethylene glycol is partly produced as a by-product from ethylene glycol during the polymerization reaction. Therefore, in addition to the case where a predetermined amount is used as a polymerization raw material, reaction conditions, additives, etc. It is also possible to control the diethylene glycol component ratio by making an appropriate selection.

These copolymerization components may be used alone or in combination of two or more. When the above-mentioned trifunctional or higher-functional copolymerization component is added, the melt tension is good, so that the moldability at the time of molding a sheet or the like is improved.
Addition of more than mol% is not preferable because it promotes gelation. Regarding these terephthalic acid, ethylene glycol and the above-mentioned copolymerizable dicarboxylic acid and diol components, they can be used in the form of a derivative capable of forming a polyester at the stage of polymerization raw material.

The crystalline polyester resin (A) used in the resin composition of the present invention is 3 in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (weight ratio = 1/1).
When measured at 0 ° C, the intrinsic viscosity is 0.5 to 1.5 dl /
g, preferably 0.5 to 1.2 dl / g, and more preferably 0.6 to 1.0 dl / g. When the intrinsic viscosity of the crystalline polyester is less than 0.5 dl / g, the strength of the molded product obtained by molding the obtained polyester resin composition is low, which is not preferable. On the other hand, the intrinsic viscosity is 1.5
When it exceeds dl / g, the moldability of the obtained polyester resin composition is poor, and the cost of the resin composition and the sheet increases, which is not preferable.

The crystallinity of the crystalline polyester resin (A) used in the resin composition of the present invention is usually 5% or more, preferably 10% or more, more preferably 15% or more.
When the crystallinity is less than 5%, the heat resistance is inferior, which is not preferable. As a crystallinity measuring method, a general measuring method such as a method using a differential scanning calorimeter or a method using density measurement is used. In the case of the differential scanning calorimeter method,
A value of 26.9 KJ / mol (140 J / g) can be used as the heat of fusion of a completely crystalline polyethylene terephthalate chain (Polymer Data Handbook, published by Baifukan). In the case of the method based on the density measurement, a value of 1.335 g / cm ³ as a completely amorphous density and a value of 1.455 g / cm ³ as a perfect crystal density can be used. However, if the density changes due to copolymerization, this must be corrected.

The amount of the crystalline polyester resin (A) used in the resin composition of the present invention is 60 to 99 parts by weight, preferably 80 to 98 parts by weight, particularly preferably 90 parts by weight based on 100 parts by weight of the resin composition. ~ 98 parts by weight. If the amount is less than 60 parts by weight, the strength of the resin composition is insufficient and 9
If the amount exceeds 9 parts by weight, the crystallization rate and impact resistance of the resin composition are poor, which is not suitable.

The thermoplastic polyester resin composition of the present invention contains a carboxylic acid-modified polyolefin (B) as an essential component as a crystallization accelerator. The carboxylic acid-modified polyolefin (B) is composed mainly of an olefin and an unsaturated carboxylic acid.

The olefin component constituting the carboxylic acid-modified polyolefin (B) is usually α-represented by ethylene, propylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene and the like. Examples include olefins. Among these, ethylene, propylene, 1
-Butene is preferred.

The carboxylic acid component constituting the carboxylic acid-modified polyolefin (B) usually has 3 to 10 carbon atoms.
Unsaturated carboxylic acids and derivatives thereof, specifically acrylic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters, fumaric acid, itaconic acid, itaconic anhydride, nadic acid, nadic acid anhydride, maleic acid, maleic anhydride , Maleic acid ester and the like are used. Among these, acrylic acid, methacrylic acid and maleic anhydride are particularly preferable. Further, a plurality of these unsaturated carboxylic acids and their derivatives can be used in combination.

Further, the carboxylic acid-modified polyolefin (B) may contain other monomers copolymerizable with α-olefins such as vinyl acetate, glycidyl methacrylate, divinylbenzene, vinylsilane, etc. within a range that does not significantly impair the effects of the present invention. It may be copolymerized.

The composition ratio of the olefin component and the unsaturated carboxylic acid component constituting the carboxylic acid-modified polyolefin (B) is such that the olefin component is usually 60 to 98 mol%, preferably 70 to 98 mol%. The component is usually 2 to 40 mol%, preferably 2 to 30 mol%. If the composition ratio of the unsaturated carboxylic acid component is less than 2 mol%, the effect of promoting crystallization is insufficient, and the amount is 40 mol%.
If it exceeds, the affinity with the low crystalline polyolefin (C) is deteriorated, which is not preferable.

The carboxylic acid-modified polyolefin (B) is
The carboxylic acid in the carboxylic acid-modified polyolefin (B) may be an ionic one partially or completely neutralized with a monovalent to trivalent metal. Neutralizing the carboxylic acid is particularly preferable because the crystallization promoting effect is improved. The metal for neutralizing carboxylic acid is usually a monovalent salt such as sodium, potassium or lithium, a divalent salt such as zinc, magnesium, calcium, cobalt, nickel, manganese or copper, or a trivalent salt such as aluminum. Salts are mentioned, preferably sodium, zinc, magnesium, and particularly preferably sodium is used. The degree of neutralization of the carboxylic acid component, which is expressed as a percentage of the neutralized carboxylic acid with respect to the total carboxylic acid, is usually 5 to 100%, preferably 5 to 80%. If the degree of neutralization of the carboxylic acid component is less than 5%, the effect of promoting crystallization due to neutralization is insufficient.

The carboxylic acid-modified polyolefin (B) is
The melt flow rate when measured according to ASTM D1238 is 0.1 to 100 g / 10 minutes, preferably 0.3 to 50 g / 10 minutes, and more preferably 0.5 to 2
It is 5 g / 10 minutes. When the melt flow rate of the modified polyolefin is less than 0.1 g / 10 minutes, the dispersibility in the crystalline polyester resin (A) is poor, the moldability is lowered, and heat deterioration due to an increase in shearing heat during kneading is caused. Is not preferable because it occurs. On the other hand, when the melt flow rate exceeds 100 g / 10 minutes, the resulting polyester resin composition has low impact resistance, which is not preferable.

The compounding amount of the carboxylic acid-modified polyolefin (B) is 0.5 to 20 with respect to 100 parts by weight of the resin composition.
Parts by weight, preferably 1 to 10 parts by weight, particularly preferably 1
~ 5 parts by weight. If it is less than 0.5 parts by weight, the crystallization promoting effect is small, and if it exceeds 20 parts by weight, the dispersion state in the polyester is poor and the strength is lowered.

The thermoplastic polyester resin composition of the present invention contains a low crystalline polyolefin (C) as an essential constituent as an impact modifier and a crystallization accelerator. The low crystalline polyolefin (C) is usually
Examples include homopolymers containing α-olefin as a constituent, copolymers containing α-olefin as a main component, and olefin-based elastomers.

The α-olefin used in the homopolymer containing α-olefin as a constituent and the copolymer containing α-olefin as a main component is usually ethylene, propylene, 1-butene or 3-methyl-1. -Butene, 4-methyl-1-pentene and the like can be mentioned.

Homopolymers containing α-olefin as a constituent component include polyethylene, polypropylene and carbon atoms of 4
The above α-olefin polymers and the like can be mentioned. Specifically, as polyethylene, in addition to high-density polyethylene, low-density polyethylene with many long-chain branches by the high-pressure method,
Examples include linear low density polyethylene produced by the low pressure method.
Examples of polypropylene include isotactic polypropylene and syndiotactic polypropylene. Examples of the α-olefin polymer having 4 or more carbon atoms include polymers such as 1-butene and 4-methyl-1-pentene, and other types of α-olefin are not limited,
Various olefin polymers are used. Of these, high-pressure low-density polyethylene and linear low-density polyethylene are preferable, and high-pressure low-density polyethylene is particularly preferable. High-density polyethylene having high crystallinity and homopolypropylene having high isotacticity are not preferable because the resin composition is inferior in impact resistance.

Further, the copolymer containing α-olefin as a main component is usually ethylene-propylene, ethylene-
In addition to ethylene-α-olefin copolymers such as 1-butene and ethylene-1-hexene copolymers, copolymers of ethylene with vinyl acetate, acrylic acid ester, methacrylic acid ester and the like can be used. In these cases, either a random copolymer or a block copolymer may be used, and a copolymer composed of three or more components is also included. Ethylene-propylene copolymers and ethylene-1-butene copolymers are preferable, and ethylene-propylene copolymers are particularly preferable. Copolymers containing these α-olefins as the main component are α-olefins within a range that does not significantly impair the effects of the present invention.
Monomers capable of copolymerizing with olefins, for example, bifunctional monomers such as divinylbenzene, derivatives of unsaturated carboxylic acids such as glycidyl methacrylate, vinylsilanes, etc. may be further copolymerized.

Specific examples of the olefin elastomer include ethylene-propylene copolymer rubber, ethylene-propylene-non-conjugated diene copolymer rubber, ethylene-
Examples thereof include amorphous or low crystalline elastic copolymers such as butene-non-conjugated diene copolymer rubber and propylene-butadiene copolymer rubber. Among these, ethylene-propylene copolymer rubber is particularly preferable. When the diene component is contained in the elastomer component, the diene component is usually 20 mol% or less of the elastomer. When it exceeds 20 mol%, the molded article obtained from the composition is greatly deteriorated by heat and the strength is lowered, which is not preferable.

Further, an olefin thermoplastic elastomer can be used as the olefin elastomer. Specifically, a crosslinked and / or non-crosslinked olefinic thermoplastic elastomer composed of an olefinic resin and an olefinic rubber is used. Some of these olefin-based thermoplastic elastomer components can be replaced with other thermoplastic elastomers as long as the effects of the present invention are not significantly impaired. Examples of other thermoplastic elastomers include ester-based thermoplastic elastomers and styrene-based thermoplastic elastomers, and ester-based thermoplastic elastomers are particularly preferably used.

As the low crystalline polyolefin (C), a homopolymer containing α-olefin as a constituent component, α-olefin
It is also possible to use a plurality of olefin resins such as a copolymer containing olefin as a main component and an olefin elastomer, and an olefin elastomer in combination.

The low crystallinity polyolefin (C) has an ultimate crystallinity as a polyolefin of usually 0 to 75%, preferably 1 to 70%, more preferably 5 to 60%. When the ultimate crystallinity exceeds 75%, the impact resistance is poor because the crystallinity in the resin composition is high, and the affinity with the carboxylic acid-modified polyolefin (B) is poor, which is not suitable. Although a completely amorphous polyolefin can be used as the low crystalline polyolefin, a polyolefin having a crystallinity of 1% or more is preferable in order to maintain the strength of the resin composition. As a method of measuring the ultimate crystallinity, a general measuring method such as a method using a differential scanning calorimeter, a method using density measurement, or a method using X-ray measurement is used. As the sample to be measured, a sample is used in which crystallization is completed by melting the sample at a melting temperature or higher and then holding the sample at a temperature at which the crystallization rate of the sample is highest.

Α as the low crystalline polyolefin (C)
When an olefin homopolymer or a copolymer containing α-olefin as the main component is used, the end temperature of the melting peak measured by a differential scanning calorimeter according to JIS K7121 may be 120 ° C. or lower. Particularly preferred. Polyolefin whose melting peak end temperature is 120 ° C. or lower has already started melting at the temperature at which the temperature rising crystallization of the crystalline polyester resin (A) is started, but in this case, the crystalline polyester resin (A) The crystallization-promoting effect on the crystal is further enhanced.

The low crystalline polyolefin (C) is AS
The melt flow rate when measured according to TM D1238 is 0.1 to 100 g / 10 minutes, preferably 0.
1 to 50 g / 10 minutes, more preferably 0.2 to 25 g
/ 10 minutes. Melt flow rate is 0.1g / 10
When it is less than minutes, crystalline polyester resin (A)
Is not preferable because it has poor dispersibility with respect to, and further deteriorates moldability and causes thermal deterioration due to an increase in shear heat generation during kneading. On the other hand, when the melt flow rate exceeds 100 g / 10 minutes, the resulting polyester resin composition has low impact resistance, which is not preferable.

When the resin composition of the present invention is used in a container such as food, it is preferable that the low crystalline polyolefin (C) does not swell with n-heptane or the like from the viewpoint of oil resistance at high temperature. . The low crystalline polyolefin (C) is compounded in an amount of 0.5 to 20 parts by weight, preferably 1 to 10 parts by weight, and particularly preferably 1 to 5 parts by weight, based on 100 parts by weight of the resin composition. If it is less than 0.5 part by weight, the effect of improving impact resistance is small, and if it exceeds 20 parts by weight, the dispersion state in the polyester is poor and the strength is lowered, which is not suitable.

In the resin composition of the present invention, the compounding ratio of the carboxylic acid-modified polyolefin (B) and the low crystalline polyolefin (C) is arbitrary. However, from the viewpoint of the balance between the crystallization acceleration effect and the impact improvement, the ratio of the low crystalline polyolefin (C) content to the carboxylic acid-modified polyolefin (B) content is 0.5 or more by weight. preferable. When the weight ratio is 0.5 or more, the impact resistance can be further improved while maintaining a high crystallization promoting effect.

Further, the thermoplastic polyester resin composition of the present invention is within a range that does not significantly impair the effects of the present invention.
In addition to the above essential components, additional components may be contained. Specifically, a phenol-based, phosphorus-based, or thioether-based antioxidant, a coloring agent such as titanium dioxide, a nucleating agent such as talc, a plasticizer, and the like may be appropriately mixed. Agent, foaming agent, flame retardant, heat stabilizer, hydrolysis resistant agent, antistatic agent, ultraviolet absorber, light stabilizer, dispersion aid, molecular weight modifier, resin additive such as various waxes, etc. Good. Depending on the purpose and use of the product, mica, calcium carbonate, glass fiber, silica,
It may contain various inorganic fillers such as whiskers. These additional components can be added in appropriate combination.

Next, the method for producing the thermoplastic polyester resin composition of the present invention will be described in detail. First, in producing the thermoplastic polyester resin composition of the present invention, the crystalline polyester resin (A), the carboxylic acid-modified polyolefin (B), and the low crystalline polyolefin (C), which are raw materials, have been conventionally known. What was manufactured by the method of can be used.

The crystalline polyester resin (A) can be produced by a conventionally known method such as melt polymerization or subsequent solid phase polymerization. By using the copolymerized polyethylene terephthalate produced by solid phase polymerization, a polyester resin composition having a high molecular weight and a smaller content of acetaldehyde can be obtained.

As the catalyst for polycondensation of the crystalline polyester resin (A) of the present invention, antimony type catalysts, germanium type catalysts, titanium type catalysts, cobalt type catalysts and other general polyesters capable of ester condensation are used. Polymerization catalysts can be used. As the co-catalyst and the stabilizer, a general polyester co-catalyst and stabilizer can be used, and phosphoric acid esters, phosphorous acid esters, acidic phosphoric acid esters and other phosphorus compounds are preferably used. . As a transesterification catalyst,
Alkali metal salts such as sodium and lithium, alkaline earth metal salts such as magnesium and calcium, metal compounds such as zinc and manganese, and other general transesterification catalysts can be used. Can be used.

Regarding the method for producing the carboxylic acid-modified polyolefin (B), for example, high-pressure radical polymerization or coordination anionic polymerization, and further, a polyolefin resin and an α, β-unsaturated carboxylic acid and / or its anhydride are used. A method such as melt kneading may be used. Further, when a treatment such as washing is performed to remove the residual carboxylic acid component, a polyester resin composition suitable for odor-sensitive contents such as food applications can be obtained.

Examples of the method for producing the low crystalline polyolefin (C) include high pressure radical polymerization and coordinated anionic polymerization. In molding the resin composition of the present invention, each component may be directly added to the molding machine by chip blending, or a composition which is melt-kneaded in advance may be used. The same applies to additional components other than the main component, which may be added at the same time as the raw material resin during melt kneading, or may be contained in the raw material resin in advance. It may be added as a dry blend with the product at the time of molding.

When the resin composition of the present invention is charged into a melt-kneader or a molding machine, each component or a melt-kneaded product thereof may be charged in an amorphous state or may be crystallized. However, in order to eliminate the deterioration of the resin and the poor bite, it is preferable to dry and crystallize the resin in advance before charging.

When the resin composition is melt-kneaded in advance, for example, each component in the form of pellets, powder, flakes, bales, and other additives and other additives are extruded as a single-screw or twin-screw kneader. It can be obtained by melt-kneading using a kneader such as a Banbury mixer, a small batch mixer, a continuous mixer, a mixing roll, a kneader, etc., and two or more kinds of them can be used in combination. Of these, an extruder or a Banbury mixer is suitable, and a single-screw type or a twin-screw type extruder is particularly preferable. In the case of melt kneading by an extruder, the temperature is usually 200 to 300 ° C, preferably 2
It is carried out by setting the temperature to 20 to 280 ° C. Each component may be added to the kneader at the same time, but it is also possible to add one component or two components first and add the other components afterwards from a side feeder or the like. By performing such a melt-kneading operation, it is possible to further improve the dispersion of the carboxylic acid-modified polyolefin and the low crystalline polyolefin in the polyester resin composition of the present invention.

The resin composition of the present invention obtained as described above is subjected to a usual molding method, that is, extrusion molding (sheet molding,
It can be formed into a sheet shape, a linear shape, and other shapes by a melt molding method such as blow molding), injection molding, or compression molding. When these melt moldings are performed, the temperature is usually set to 200 to 300 ° C, preferably 220 to 280 ° C.

Particularly, the resin composition of the present invention has a thickness of 0.0
When molded into a sheet of 5 to 3 mm and then thermoformed, a molded product excellent in heat resistance, low temperature impact resistance and the like can be obtained. If the thickness is less than 0.05 mm, the self-holding property of the molded body is poor, and if the thickness exceeds 3 mm, it is difficult to obtain a sheet having good surface properties, which is not preferable.

In order to form the resin composition of the present invention into a sheet, a general sheet forming method, for example, a uniaxial or biaxial extruder is used, and a die is optionally provided via a gear pump, a filter and the like. A connected molding machine or the like can be used. The temperature of the molding machine is usually 200 to 300 ° C,
It is preferably carried out by setting the temperature at 220 to 280 ° C. The resin composition to be charged is preferably dried, and the hopper to be charged to the molding machine is also preferably a closed type. The sheet extruded from the die is usually obtained by being wound by a casting roll or a roll with a contact device and cooled. In order to stabilize the surface temperature of the roll and improve the cooling efficiency of the sheet, the roll preferably circulates a refrigerant inside. When the thickness of the sheet exceeds 1 mm, it can be obtained in a plate shape by taking it out in a flat shape and cooling it.

The thermoplastic polyester resin composition of the present invention is used at a relatively low temperature of 130 ° C. or lower when injection-molded to obtain a molded piece or when pressure-pressing and / or vacuum-forming a sheet to obtain a container. Molding with a die is possible, and a product with high crystallinity can be obtained in a short molding cycle. The polyester resin composition of the present invention and the molded article obtained as described above have excellent heat resistance, thermal stability, cold resistance, impact resistance, moldability, etc. It can be suitably used as a molded part or the like.

[0052]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. Examples 1 to 7 and Comparative Examples 1 to 6 The resins used below are shown.

P-1: Homopolyethylene terephthalate resin (Novapex GS400, IV manufactured by Mitsubishi Chemical Co., Ltd.)
Value 0.70, crystallinity 28%) P-2: dicarboxylic acid component is terephthalic acid, diol component is ethylene glycol 96 mol%, 1,4-
A copolyester resin having an IV value of 0.70, which is composed of 4 mol% of cyclohexanedimethanol. Crystallinity 13%. P-3: Copolyester resin having an IV value of 0.73 in which the dicarboxylic acid component is 70 mol% terephthalic acid and 30 mol% isophthalic acid, and the diol component is ethylene glycol. Amorphous. -I-1: ethylene-methacrylic acid copolymerized ionomer (manufactured by Mitsui DuPont, high milan 1707, sodium salt, MFR 0.9) -I-2: maleic anhydride-modified polyolefin resin (manufactured by Mitsubishi Chemical Corporation, Novatec AP229L, MFR1. 1) -E-1: Low-density polyethylene (Mitsubishi Chemical Co., Mitsubishi Polyethylene LF225M, MFR 0.8, melting point 113 ° C) -E-2: Low-density polyethylene (Mitsubishi Chemical Co., Mitsubishi Polyethylene LF480M, MFR1.5) Melting point 117 ° C.) E-3: Highly crystalline homopolypropylene (Mitsubishi Chemical Co., Mitsubishi Polypro MA3, MFR10)

The IV value of the polyester resin is the value of intrinsic viscosity [dl / g] measured at 30 ° C. in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (weight ratio = 1/1). ] Is shown. For polyester resin,
The amount of diethylene glycol present as a by-product during the polymerization is
It is not included in the composition shown below. The crystallinity of the polyester resin was measured using a differential scanning calorimeter according to JIS K7122, and calculated from the calorific value at the time of melting when an amorphous sample was heated at a rate of 20 ° C./min. . At this time, a value of 140 J / g was used as the heat of fusion of complete crystals. MFR of polyolefin is ASTM D1238
Melt flow rate [g / 10 min]
Indicates. The melting point indicates the end temperature of the melting peak measured by a differential scanning calorimeter according to JIS K7121.

Using the TEX30 twin-screw extruder manufactured by Japan Steel Works, Ltd. at the compounding amounts shown in Table 1 at 280 ° C.
(Comparative Example 6 only, 260 ° C.) was melt-kneaded, and a pelletizer was used to produce chips. At this time, the polyester to be used had a water content adjusted to 50 ppm or less by a dryer in advance and was subjected to melt kneading. The chips of the obtained composition were dried with a drier to remove water, and then 40 m manufactured by Tanabe Plastic Co., Ltd.
An amorphous sheet having a thickness shown in Table 1 was formed using a mφ uniaxial sheet forming machine under the condition of 280 ° C. (260 ° C. in Comparative Example 6 only) using a T die and a roll.

The molded sheet was measured for crystallization temperature, heat resistance, low temperature impact resistance and yield strength by the following methods. Regarding the heat resistance, low temperature impact resistance, and yield strength tests, the sheet was heated at 170 ° C. for 10 seconds to give a crystallized sheet, which was used as a test piece.

Crystallization temperature: a sheet was cut out and
Measurement was performed using a thermal analyzer TA2000 type manufactured by A Instruments. First, the measurement is performed at a rate of 20 ° C / min for 3
The temperature was raised to 00 ° C., held for 3 minutes, and then rapidly cooled to obtain a completely amorphous sample. This was heated again at a rate of 20 ° C./min, and the temperature at which crystallization started at the crystallization peak when the temperature was raised was measured.

Heat resistance: The sheet was cut into a size of 50 mm × 100 mm, and this was placed in an oven at 130 ° C. for 1
The degree of deformation after time was observed. Regarding the change in shape, ⊚ means that there is no change at all, ◯ means that some bending occurs, Δ means that bending occurs, and × means that it deforms. Each sample was tested five times, and if there were variations in the test results, it was judged as a bad result.

Low temperature impact resistance test: 100 mm × sheet
Cut out to 100 mm, cool to -20 ° C, and
After storage for a period of time, a falling weight impact test was carried out at -20 ° C in accordance with ASTM D3763. In the measurement, the total energy required for destruction was measured, converted into a value for a 350 μm thick sheet, and compared. Yield strength: A sheet was punched into a dumbbell shape, and this was tested by a tensile tester according to ASTM D882.
The yield strength was determined by measuring at 10 mm / min under conditions of ° C and relative humidity of 50%. Table 2 shows the test results of the compositions of Examples 1 to 7 and Comparative Examples 1 to 6.

[0060]

[Table 1]

[0061]

[Table 2]

[0062]

INDUSTRIAL APPLICABILITY The thermoplastic polyester resin composition of the present invention is excellent in heat resistance, heat stability, cold resistance, impact resistance, moldability and the like, and particularly, it has a high crystallization rate, and a molded product obtained. Has excellent heat resistance and low temperature impact resistance. Therefore, the sheet obtained from the polyester resin composition of the present invention is suitable for use as a molded product such as a container used when heating food in a microwave oven or the like.

Claims (7)

[Claims] 1. (A) 80 mol% or more of the dicarboxylic acid component is terephthalic acid, 80 mol% or more of the diol component is ethylene glycol, and the intrinsic viscosity is 0.5 to.
Crystalline polyester resin 60-9 having 1.5 dl / g
9 parts by weight, (B) melt flow rate of 0.1-100
Carboxylic Acid Modified Polyolefin 0.5 g / 10 min
˜20 parts by weight and (C) melt flow rate of 0.1
A thermoplastic polyester resin composition prepared by blending 0.5 to 20 parts by weight of a low crystallinity polyolefin of 100 g / 10 min. 2. An ionic copolymer in which the carboxylic acid-modified polyolefin (B) is a copolymer of an α-olefin and an α, β-unsaturated carboxylic acid, which is partially or completely neutralized with a monovalent metal. The resin composition according to claim 1, which is a polymer. 3. The carboxylic acid-modified polyolefin (B) is an ionic copolymer obtained by partially or completely neutralizing a copolymer of an α-olefin and acrylic acid and / or methacrylic acid with sodium ions. The resin composition according to claim 1, wherein 4. The melting peak end temperature of the low crystalline polyolefin (C) determined by a differential scanning calorimeter is 120.
The resin composition according to claim 1, wherein the resin composition has a temperature of not higher than ° C. 5. The resin composition according to claim 1, wherein the low crystalline polyolefin (C) is low density polyethylene obtained by a high pressure method. 6. The weight ratio of the low crystallinity polyolefin (C) to the carboxylic acid modified polyolefin (B) is 0.5 or more, according to any one of claims 1 to 5. Resin composition. 7. A thermoplastic polyester resin sheet, which is formed by molding the polyester resin composition according to any one of claims 1 to 6 to a thickness of 0.05 to 3 mm.