JP2002348482A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide at a low cost a thermoplastic resin composition having not only excellent fluidity but also high mechanical strength or toughness, without incurring occurrence of bleed out or reduction of thermal resistance and durability and further impairing transparency. SOLUTION: The thermoplastic resin composition containing from 70 to 99% by mass of a specific thermoplastic resin (A) and from 1 to 30% by mass of a specific polyester resin (B), wherein the polyester resin (B) is composed of a specific acid component containing from 80 to 100 [% by mol] of aromatic dicarboxylic acid units and a specific alcohol component containing ethylene glycol units, wherein the difference between the refractive index (a) of the thermoplastic resin (A) and the refractive index (b) of the polyester resin (B) is 0.029 or less, and the melt viscosity Cb of the polyester resin (B) is less than 0.4 time the melt viscosity Ca (Pa.s) of the thermoplastic resin (A).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition, and more particularly, to a thermoplastic resin composition in which mechanical properties are maintained at a high level and moldability is further improved.

[0002]

2. Description of the Related Art Condensed thermoplastic resins generally have heat resistance,
It is excellent in mechanical strength, dimensional stability, electrical properties, transparency, etc., and is used for various uses such as mechanical parts, electronic parts, and parts for vehicles. Polyester, one of the condensed thermoplastic resins, is particularly excellent in chemical resistance, heat resistance, mechanical strength, toughness, moldability, and fluidity, so it can be used to obtain thin molded products by injection molding. Are suitable. For example, polyethylene terephthalate (PET) resin is widely used alone or as a composite material reinforced with glass fiber or the like for use in thin or complex-shaped parts.

It is known that fluidity, which is one of the important properties of a resin, generally depends on its molecular weight. In the case of PET having a number average molecular weight of 10,000 to 40,000, meltability is an indicator of fluidity. Viscosity C (Pa · s)
And the number average molecular weight Mn of PET, the relationship shown in Formula 3 below generally holds, and the lower the molecular weight of PET, the smaller the melt viscosity and the better the fluidity. Therefore, PET or the like having a small molecular weight and high fluidity has been used for injection molding of a thin or complex shape. C = 3.5 × 10−10 × Mn ^2.7 (Equation 3) (However, in Equation 3, the melt viscosity C is a value measured at 270 ° C. and a shear rate of 1200 / (1 / sec).)

In addition to the method of controlling the molecular weight of a resin to control its flowability, a method of modifying the flowability of a resin is to add a low molecular weight compound having good solubility in a resin as a plasticizer. Also, it is generally well known that only the melt viscosity is reduced without changing the molecular weight of the resin, and it is industrially practiced for vinyl chloride resin and the like. Further, a modification method capable of improving the moldability without impairing the excellent various properties of the aromatic plastic by blending the aromatic plastic with a styrene oligomer having a specific molecular weight and a specific molecular weight distribution is disclosed in Japanese Unexamined Patent Application Publication No. Hei 9-1997. No. 328589.

On the other hand, in recent years, various attempts have been made to recover and reuse useful PET resin from PET resin waste. For example, JP-A-5-293885 discloses a method for producing a polyester sheet by melt-extruding a low-viscosity polyester resin such as a recovered polyester resin under reduced pressure,
JP-A-6-255645 discloses solid-phase polymerized regenerated P.
A method for producing a bottle by biaxially stretching an ET resin is disclosed. However, the sheets and bottles obtained by these methods are inferior in physical properties such as the intrinsic viscosity of the recovered PET resin, which is a raw material, as compared with pelletized PET resins on the market. There is a problem that characteristics such as important mechanical strength cannot be sufficiently obtained. Methods for improving mechanical strength such as impact resistance include, for example, Japanese Patent Publication No. 58-47419 and Japanese Patent Publication No.
JP-A-3-4566 and JP-B-1-26380 disclose methods of melting and kneading various epoxy group-containing ethylene copolymers and the like.

[0006]

However, there is a problem in the above-mentioned method for improving the fluidity and impact resistance of a resin. That is, in the method of controlling the fluidity by adjusting the molecular weight of the resin, mechanical properties such as mechanical strength and toughness of the thermoplastic resin also strongly depend on the molecular weight, the higher the molecular weight, the better the mechanical properties Therefore, when a low-molecular-weight thermoplastic resin having excellent fluidity is used, there is a problem that the mechanical properties of the obtained molded product are deteriorated. Therefore, according to the mechanical properties required for the product,
The lower limit of the molecular weight of the usable thermoplastic resin was determined, and it was difficult to use a thermoplastic resin having sufficient fluidity. In the method of modifying the fluidity by adding a low molecular weight substance of a thermoplastic resin, the heat during melt shaping causes an exchange reaction between the low molecular weight substance and the thermoplastic resin, resulting in a decrease in the molecular weight and a variation in the molecular weight. As a result, there is a problem that the mechanical properties of the molded body are deteriorated. If a low-molecular weight plasticizer is added to a thermoplastic resin to maintain its mechanical strength and reduce only the melt viscosity, the bleed-out of the plasticizer will cause the resin to become dirty, and the glass transition temperature will decrease, resulting in heat resistance. And other problems. Furthermore, in order to plasticize a resin having good chemical resistance such as PET in addition to such a decrease in physical properties, it is necessary to select a special compound as a plasticizer, and the cost and durability are also restricted. was there. In addition, for example, in the case of polyester, the addition of a polyester incompatible with the polyester significantly lowers the transparency. Therefore, there is a problem when high transparency is required. Furthermore, when the plasticizer itself is a liquid, there are practical restrictions such as difficulty in hopper blending with polyester.

According to the methods described in JP-B-58-47419, JP-B-63-4566, JP-B-1-26380, etc., although the impact resistance is improved, the polyester resin and the epoxy group New problems occur such as the melt viscosity remarkably increasing due to the chemical reaction occurring between the ethylene copolymer and the fluidity (moldability), and the transparency being significantly impaired. .
Also, when using recycled polyester resin for injection molding, most of the PET resin used for bottles has a higher molecular weight than general PET for injection molding, so thin molded products such as boxes and containers and large There is also a problem that when molding a molded article or the like, fluidity is insufficient, and it is difficult to obtain a good product. As described above, it has conventionally been very difficult to obtain a thermoplastic resin having low melt viscosity, excellent fluidity, and maintaining physical properties such as mechanical properties at low cost.

An object of the present invention is to provide a thermoplastic resin composition having excellent fluidity and high mechanical strength and toughness without causing bleed-out, deterioration in heat resistance and durability, and further improving transparency. It is also to provide at low cost without spoiling.

[0009]

Means for Solving the Problems The thermoplastic resin composition of the present invention has a number average molecular weight of 18,000 or more and 27
70-99% by mass of a thermoplastic resin (A) having a melt viscosity at 0 ° C of 200 Pa · s or more, a polyester resin having a number average molecular weight of 3000 or more and a melt viscosity at 270 ° C of less than 200 Pa · s (B) a thermoplastic resin composition containing 1 to 30% by mass, and a polyester resin (B)
Is composed of an acid component containing 80 to 100 [mol%] of an aromatic dicarboxylic acid unit and an alcohol component containing an ethylene glycol unit, and the mole fraction of dibasic acid units other than the aromatic dicarboxylic acid unit in the acid component And the molar fraction of diacid base units other than ethylene glycol units in the alcohol component is 50 [mol%] or less, and the molar fraction of a polyvalent component contained in the acid component and the alcohol component Is from 0.05 to 3 [mol%] with the molar fraction of the polyvalent component contained in
The refractive index a of the thermoplastic resin (A) and the refractive index b of the polyester resin (B) satisfy the following formula 1, and the melt viscosity Ca (Pa · s) of the thermoplastic resin (A) and the polyester The resin (B) is characterized in that the melt viscosity Cb satisfies the following expression (2). | Ab− ≦ 0.029 (Equation 1) Cb <0.4 × Ca (Equation 2) (However, in Equation 2, the melt viscosities Ca and Cb are 27
It is a value measured at 0 ° C. and a shear rate of 1200 (1 / second). 4) Of the acid components constituting the polyester resin (B), 4
It is preferable that 0 [mol%] or more be isophthalic acid units and / or phthalic acid units. The thermoplastic resin (A) and the polyester resin (B) are incompatible,
Particle size 0.02-5μ in continuous phase of thermoplastic resin (A)
m of the polyester resin (B) particles are preferably dispersed. The thermoplastic resin (A) is preferably a polycarbonate resin and / or a polyamide resin.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
As the thermoplastic resin (A) used in the present invention, polyester resin, polyarylate resin, polycarbonate resin, polyphenylene ether resin, polyamide resin,
Examples thereof include a polysulfone resin, a polyethersulfone resin, and a polyphenylene sulfide resin, and these can be used alone or in combination of two or more. Among these thermoplastic resins (A), polyester resins,
When using polycarbonate resin and polyamide resin,
Since a molded article having excellent transparency can be obtained, it is preferable to use these resins particularly for applications requiring transparency.

Here, the polyester resin used as the thermoplastic resin (A) is a thermoplastic polyester resin containing a hydroxycarboxylic acid compound as a structural unit, or
It is a thermoplastic polyester resin having an acid component such as a dicarboxylic acid and an alcohol component such as a diol as constituent units, and may be a mixture thereof. Examples of the hydroxycarboxylic acid unit include malic acid, citric acid, p-hydroxybenzoic acid, p-hydroxyethylbenzoic acid, and the like.

The dicarboxylic acid unit includes oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, sebacic acid, azelaic acid, decanedicarboxylic acid, dodecandionic acid, dimer acid, 1,3 or 1,4-cyclohexane Dicarboxylic acid, cyclopentanedicarboxylic acid,
Aliphatic dicarboxylic acids such as 4,4'-dicyclohexyldicarboxylic acid; phthalic acid, terephthalic acid, isophthalic acid,
Naphthalene-1,4 or 2,6-dicarboxylic acid, anthracenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenoxyethanedicarboxylic acid,
4,4′-diphenyl ether dicarboxylic acid, 4,4 ′
Aromatic dicarboxylic acids such as -diphenylsulfondicarboxylic acid, 5-sulfoisophthalic acid and sodium 3-sulfoisophthalate, and ester-forming derivatives thereof. As the diol unit, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, dodecanediol, dimer diol, cyclohexanediol , Cyclohexanedimethanol, hydroquinone, 4,4'-
In addition to dihydroxybiphenyl, bisphenols,
2,2-bis (4-β-hydroxyethoxyphenyl)
And propane and the like and ester-forming derivatives thereof.

The polyester resin is a resin obtained by using the above units in combination as necessary. Among them, a polyester resin comprising an aromatic dicarboxylic acid and ethylene glycol as main components is preferable. Preferred is a polyester in which at least 80 [mol%] of the components are terephthalic acid and at least 60 [mol%] of the alcohol components are ethylene glycol. Particularly, polyesters in which at least 80 [mol%] of the acid component is terephthalic acid and at least 80 [mol%] of the alcohol component is ethylene glycol are widely used as PET or modified PET, and are preferred. Can be used.

Further, the thermoplastic resin (A) used in the present invention may be a recycled polyester. The recycled polyester is a recovered PET resin or a non-standardized PET resin that is formed again as a molded product such as a PET bottle or a food tray and then collected again. Also,
The recycled polyester may be an extraordinary product generated at the time of molding a PET sheet, a container, or the like.

The polycarbonate resin used as the thermoplastic resin (A) includes 2,2'-bis (4-hydroxyphenyl) propane (hereinafter referred to as bisphenol A), 4,4'-dihydroxydiphenylalkane,
4,4'-dihydroxydiphenyl sulfone, 4,4 '
Preferred are those which use at least one selected from -dihydroxydiphenyl ether as a main raw material, and particularly those which are manufactured using bisphenol A as a main raw material. Specifically, polycarbonate obtained by using the above bisphenol A as a dihydroxy component and by a transesterification method or a phosgene method is preferable. Further, a part of bisphenol A, preferably 10 [mol%] or less, is converted to 4,4'-dihydroxydiphenylalkane or 4,4'-dihydroxydiphenylsulfone, 4,4 '.
Those substituted with -dihydroxydiphenyl ether or the like are also preferable.

The polyamide resin used as the thermoplastic resin (A) is synthesized by condensation of a diamine and a dicarboxylic acid, condensation of an amino acid, ring opening of a lactam, and the like. For example, lactam polymers such as butyrolactam, δ-valerolactam, ε-caprolactam, enantholactam, ω-laurolactam, and heavy acids such as aminocarboxylic acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. Coalescence, hexamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, undecamethylenediamine, 2,2,4-
Or a diamine unit such as 2,4,4-trimethylhexamethylenediamine, 1,3- or 1,4-bis (aminomethyl) cyclohexane, m- or p-xylylenediamine, and glutaric acid, adipic acid, or suberic acid ,
Sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid, polycondensates with dicarboxylic acid units such as isophthalic acid,
And copolymers thereof. Specific examples thereof include nylon 4, nylon 6, nylon 7, nylon 9, nylon 12, nylon 66, nylon 69, and nylon 61.
0, nylon 611, nylon 612, nylon 6T,
Nylon 6I, nylon MXD6, nylon 6/66,
Nylon 6/610, Nylon 6/12, Nylon 6 /
6T, nylon 6I / 6T and the like. Further, in order to improve transparency, trimethylhexamethylenediamine, bis (4-aminocyclohexyl) methane, bis- (4-amino-1,2-methylcyclohexyl) methane, bis- (4-amino-3-methyl) Cyclohexyl) methane or the like can be copolymerized.

As the thermoplastic resin (A), a resin whose melt viscosity measured at 270 ° C. at a shear rate of 1200 (1 / sec) is 200 Pa · s or more is used. When the melt viscosity is less than 200 Pa · s, the fluidity is good, but the mechanical strength, toughness, heat resistance and the like are insufficient. The thermoplastic resin (A) has a number average molecular weight Mn of 1
8000 or more, preferably 21,000
The above are used. Number average molecular weight Mn is 1800
If it is less than 0, the mechanical properties of the thermoplastic resin (A), particularly the impact resistance, are low. When the molecular weight is 18,000 or more, properties such as mechanical properties, toughness, and impact resistance are excellent, and the molecular weight is 210
If it is 00 or more, these characteristics are more excellent. further,
The most preferred thermoplastic resin (A) has a number average molecular weight Mn of 22,000 to 40000. If such a thermoplastic resin (A) having a number average molecular weight Mn is used, the mechanical properties of the thermoplastic resin composition finally obtained can be improved. Both characteristics and fluidity are excellent in a well-balanced manner.

The polyester resin (B) used in the present invention has a molecular weight of 3000 or more. When the molecular weight is less than 3000, the polyester resin (B) easily bleeds out of the finally obtained thermoplastic resin composition, and the mechanical strength, toughness,
The problem that the heat resistance or the like is reduced is likely to occur. Further, the transesterification reaction proceeds and the thermoplastic resin (A)
The risk of significantly lowering the molecular weight of Also,
The effect of modifying the fluidity of the thermoplastic resin (A) by blending the polyester resin (B) is also reduced. It is not clear why the fluidity-modifying effect is reduced, but the compatibility with the thermoplastic resin (A) is probably too high, and the thermoplastic resin (A) and the polyester (B) in the thermoplastic resin composition are not compatible with each other. It is considered that this is caused by the disappearance of the phase separation structure. The preferred molecular weight of the polyester resin (B) is 5
When the molecular weight is 000 or more and 5000 or more, bleed out from the thermoplastic resin composition is significantly reduced.
The molecular weight is more preferably 10,000 or more, and the degree of reduction in the molecular weight of the thermoplastic resin (A) is very small and is within an acceptable range even when transesterification occurs partially at such a molecular weight. In addition, from the viewpoint of maintaining the physical properties of the thermoplastic resin composition, the most preferable molecular weight of the polyester resin (B) is 20,000 or more, but the optimum molecular weight is the molecular weight and the melt viscosity of the thermoplastic resin (A), It is appropriately selected according to the use of the thermoplastic resin composition.

The polyester resin (B) contains 270
It has a melt viscosity of less than 200 Pa · s measured at ° C. When the melt viscosity is 200 Pa · s or more, the effect of improving fluidity cannot be obtained when blended with the thermoplastic resin (A).
Preferably, a polyester resin (B) having a melt viscosity at 270 ° C. of less than 100 Pa · s is used.

The acid component constituting the polyester resin (B) of the present invention contains from 80 to 100 [mol%] of aromatic dicarboxylic acid units from the viewpoint of heat resistance, and preferably from 85 to 100 [mol%].
100 [mol%]. As the aromatic dicarboxylic acid unit, terephthalic acid, isophthalic acid, naphthalene-
1,4 or 2,6-dicarboxylic acid, anthracenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,
Examples thereof include 4′-diphenyl ether dicarboxylic acid, 5-sulfoisophthalic acid, and sodium 3-sulfoisophthalate, and ester-forming derivatives thereof can also be used. Examples of the ester-forming derivatives include lower alkyl esters, aryl esters, carbonates, and acid halides. In particular, it is preferable that 40 [mol%] or more of the acid components constituting the polyester resin (B) are isophthalic acid units and / or phthalic acid units. If the aromatic dicarboxylic acid unit in the acid component is less than 80 [mol%], the refractive index of the polyester resin (B) decreases, and the transparency of the finally obtained thermoplastic resin composition also decreases. Examples of the dibasic acid unit other than the aromatic dicarboxylic acid unit include an aliphatic dicarboxylic acid unit, and specific examples thereof include oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, sebacic acid, azelaic acid, and dodecane Examples include dionic acid, dimer acid, 1,3 or 1,4-cyclohexanedicarboxylic acid, cyclopentanedicarboxylic acid, 4,4′-dicyclohexyldicarboxylic acid, and the like, or ester-forming derivatives thereof.

The alcohol component constituting the polyester resin (B) of the present invention contains an ethylene glycol unit, and other components include diethylene glycol, triethylene glycol, propylene glycol, 1,4-butanediol, and 1,6-hexane. Diol, neopentyl glycol, dimer diol, cyclohexanediol, cyclohexanedimethanol, 1,1-bis (4- (2-
Hydroxyethoxy) phenyl) cyclohexane, 4,
4'-bis (2-hydroxyethoxy) benzene, 2,
2-bis (4-β-hydroxyethoxyphenyl) propane or the like may be contained as a structural unit.

In the polyester resin (B) used in the present invention, the mole fraction of dibasic acid units other than the aromatic dicarboxylic acid unit in the acid component and the mole fraction of the dibasic acid unit other than the ethylene glycol unit in the alcohol component are used. The sum of the mole fractions of the acid-base units is 50 [mol%] or less. By setting the sum of these mole fractions particularly in such a range, a decrease in the refractive index of the polyester resin (B) can be suppressed, and the transparency of the polyester resin (B) can be maintained.

Further, the acid component and / or the alcohol component of the polyester resin (B) used in the present invention contains a polyvalent component as a constituent, and the mole fraction of the polyvalent component contained in the acid component; The sum with the mole fraction of the polyvalent component contained in the alcohol component is in the range of 0.05 to 3 [mol%]. That is, the polyvalent carboxylic acid unit contains 0.05 to
If the alcohol component contains 0.05 to 3 mol%, or the alcohol component contains 0.05 to 3 mol%, the mole fraction of the polyhydric component contained in the acid component and the alcohol component The sum of the mole fractions of the polyvalent components is 0.05
To 3 [mol%] in some cases. Here, specific examples of the trivalent or more polyvalent carboxylic acid include polyvalent carboxylic acids such as trimellitic acid, pyromellitic acid and anhydrides thereof, and trimethylolpropane as the trivalent or more polyhydric alcohol. Pentaerythritol, glycerin and the like. When the trivalent or higher carboxylic acid and the trivalent or higher alcohol are contained within the above range, the structure of the polyester resin (B) is branched, and as a result,
Fluidity, toughness, of the finally obtained thermoplastic resin composition,
Better performance balance such as impact resistance.

A molar fraction of a polyvalent component contained in the acid component,
If the sum with the mole fraction of the polyvalent component contained in the alcohol component is less than 0.05 [mol%], the effect of using these will not be sufficiently exhibited, and if it exceeds 3 [mol%],
The gelation makes it difficult to control the reaction for producing the polyester resin (B). More preferably, it is in the range of 0.1 to 2 [mol%]. The preferred amount of the polyvalent component also depends on the molecular weight of the polyester resin (B). In particular, when the polyester resin (B) contains 0.2 to 2 trivalent or tetravalent polycarboxylic acids or polyhydric alcohols as constituent units on average per one molecule of the polyester resin (B), The fluidity is efficiently improved, or the impact resistance of the finally obtained thermoplastic resin composition is stably exhibited. The approximate molecular weight of the polyester resin (B) can be measured by gel permeation chromatography, and the number of polyvalent components per molecule can be easily calculated from the obtained number average molecular weight and the amount of polyvalent component used. The effect of further increasing the performance balance by branching becomes apparent when the amount of the polyvalent component per molecule of the polyester resin (B) is 0.2 or more. In the production of the resin (B), the viscosity rises sharply at the end of the polymerization, and it tends to be relatively difficult to produce with good reproducibility.

The polyester resin (B) can be produced by a known direct polymerization method or transesterification method. In the esterification reaction or transesterification reaction, a commonly used esterification catalyst or transesterification catalyst such as titanium butoxide, dibutyltin oxide, magnesium acetate, and manganese acetate can be used, if necessary. After the esterification reaction or transesterification reaction, water or alcohol generated in the reaction is removed according to a conventional method. In the polymerization reaction, it is preferable to carry out the polymerization while distilling and removing the diol component under a vacuum at a pressure of 20 kPa or less. For the polymerization, a known polymerization catalyst such as titanium butoxide, dibutyltin oxide, tin acetate, zinc acetate, tin disulfide, antimony trioxide, and germanium dioxide can be used. Further, the polymerization temperature and the amount of the catalyst are not particularly limited, and can be arbitrarily set as needed.

The terminal carboxyl group or terminal hydroxyl group of the polyester resin (B) may be replaced by another terminal group. The so-called end-capping treatment can be carried out, for example, by coexisting an appropriate amount of a monocarboxylic acid or a monoalcohol during the polymerization of the polyester resin (B),
The effect of suppressing the transesterification occurring at the time of melt-mixing with the thermoplastic resin (A) can be expected by the terminal sealing. The molecular weight of the polyester resin (B) used in the present invention is 10,000
When the end capping is performed in the case where the amount is not more than 2 or the amount of the polyfunctional component in the polyester resin (B) is 2 [mol%] or more, excessive transesterification can be suppressed, and even when the heat history is high and long-term. Even in the case of receiving, the performance balance of the finally obtained thermoplastic resin composition can be kept stable.

The mixing ratio of the thermoplastic resin (A) and the polyester resin (B) in the thermoplastic resin composition of the present invention is as follows:
The thermoplastic resin (A) is in the range of 70 to 99% by mass, and the polyester resin (B) is in the range of 1 to 30% by mass. When the amount of the polyester resin (B) is less than 1% by mass, the fluidity of the thermoplastic resin (A) can be sufficiently improved. When the amount exceeds 30% by mass, the mechanical strength, toughness, The durability etc. decrease.

Further, in the thermoplastic resin composition of the present invention, the refractive index a of the thermoplastic resin (A) and the refractive index b of the polyester resin (B) must satisfy the following formula (1). | Ab | ≦ 0.029 (formula 1) Here, the refractive index is a value measured at room temperature. If the difference between the refractive index a of the thermoplastic resin (A) and the refractive index b of the polyester resin (B) exceeds 0.029, the thermoplastic resin composition becomes opaque and its use is restricted, and industrial use is restricted. Use value is significantly reduced. In order to more reliably maintain the transparency of the thermoplastic resin composition, the refractive index a of the thermoplastic resin (A) and the refractive index b of the polyester resin (B)
Is preferably 0.015 or less, more preferably 0.005 or less, and most preferably 0.002 or less.

Further, the melt viscosity Ca of the thermoplastic resin (A)
(Pa · s) and melt viscosity Cb of polyester resin (B)
Needs to satisfy the following expression (2). Cb <0.4 × Ca (Equation 2) The melt viscosities Ca and Cb are values measured at 270 ° C. and a shear rate of 1200 (1 / sec). When the melt viscosity Cb of the polyester resin (B) is at least 0.4 times the melt viscosity Ca of the thermoplastic resin (A), the thermoplastic resin (A)
The effect of improving the fluidity of the powder is small, and a high balance between practical properties such as mechanical strength and fluidity cannot be obtained. Preferably, the melt viscosity Cb of the polyester resin (B) is 0.2 times or less the melt viscosity Ca of the thermoplastic resin (A).
When the melt viscosity Cb of the polyester resin (B) is 0.2 times or less of the melt viscosity Ca of the thermoplastic resin (A), the fluidity of the thermoplastic resin composition is further increased, and excellent fluidity and mechanical properties are obtained. Are expressed in a very well-balanced manner. For example, when recycled PET is used as the thermoplastic resin (A), the polyester resin (B) is often more expensive than the thermoplastic resin (A). It is preferred to reduce the amount used. In such a case, if the melt viscosity Cb of the polyester resin (B) is 0.2 times or less of the melt viscosity Ca of the thermoplastic resin (A), it is sufficient even if the amount of the polyester resin (B) is 20% by mass or less. Thus, a thermoplastic resin composition having excellent fluidity can be obtained. More preferably, the melt viscosity Cb of the polyester resin (B) is 0.1 times or less of the melt viscosity Ca of the thermoplastic resin (A). In such a case, the content of the polyester resin (B) is 1% in the thermoplastic resin composition.
Even when the content is 5% by mass or less, the thermoplastic resin composition exhibits extremely excellent fluidity, can maintain high heat resistance and mechanical properties, and has a better balance between these properties.

In the thermoplastic resin composition of the present invention, the thermoplastic resin (A) and the polyester resin (B) are preferably incompatible with each other, and the polyester is contained in the continuous phase of the thermoplastic resin (A). When the resin (B) particles are dispersed, both the mechanical properties and the fluidity are particularly excellent. The size of the polyester (B) particles in the continuous phase of the thermoplastic resin (A) may vary depending on kneading conditions, molding conditions, and the like, and is not particularly limited. )) Is preferably in the range of 0.02 to 5 μm. If the particle diameter is less than 0.02 μm, the fluidity of the thermoplastic resin (A) may not be sufficiently improved, and if it is more than 5 μm, the thermoplastic resin (A) and the polyester resin (B)
Of the thermoplastic resin composition may be insufficient, resulting in a decrease in mechanical strength and toughness of the thermoplastic resin composition. More preferably, the particle size of the polyester (B) is in the range of 0.02 to 2 μm. In such a case, the fluidity, mechanical strength, and toughness of the thermoplastic resin composition are both excellent, and the balance between them becomes optimal. The state of the thermoplastic resin (A) phase and the polyester resin (B) phase can be confirmed, for example, by observing the thermoplastic resin composition after melt shaping with a transmission electron microscope.

The thermoplastic resin composition of the present invention can be obtained by mixing the thermoplastic resin (A) and the polyester resin (B), but the mixing method is not particularly limited.
In a known method usually used when mixing resins,
What is necessary is just to mix so that it may become substantially uniform as a whole.
For example, when a melt mixing method is adopted, the melt mixing may be performed at 200 to 300 ° C. using a melt extruder. As a melt extruder, for example, a single screw extruder, a twin screw extruder,
A multilayer extruder can be used. In some cases, it is also possible to omit the work of kneading and simultaneously perform melt mixing and molding by an extruder or an injection molding machine, etc.
These can be appropriately determined according to the screw configuration of the molding machine, the use of the molded product, and the like. In the production of the thermoplastic resin composition, a part of the thermoplastic resin (A) and the polyester resin (B) may be mixed to form a master batch, and then the remaining thermoplastic resin (A) may be mixed. Further, in addition to the above-mentioned thermoplastic resin (A) and polyester resin (B), other resins may be mixed into the thermoplastic resin composition, if desired. Further, the thermoplastic resin composition of the present invention may be blended with various additives or fillers for imparting specific performance. Examples of additives and fillers include reinforcing fibers such as glass fibers and carbon fibers, inorganic particles such as silica, talc, kaolin and calcium carbonate, pigments such as titanium oxide and carbon black, ultraviolet absorbers, mold release agents. And flame retardants.

Such a thermoplastic resin composition has high mechanical properties, particularly high impact resistance and toughness, and excellent fluidity, and also has excellent bleed-out, heat resistance, and durability. Moreover, it is inexpensive. Therefore, the thermoplastic resin composition is extremely useful as a material for injection molding used for thin-walled molded products such as partition boards, panels, cases and cups, and especially for large-sized molded products such as trash boxes and pallets using recycled polyester.

[0033]

The present invention will be described below in detail with reference to examples. In addition, the part in an example represents a mass part unless there is particular description. Reference Example In the examples and comparative examples, the following thermoplastic resins (A1) to (A4) were used. Thermoplastic resin (A1): Dicarboxylic acid unit is composed of terephthalic acid, diol unit is composed of 67 [mol%] of ethylene glycol and 33 [mol%] of 1,4-cyclohexanedimethanol, and has a refractive index of 1.560. Polyester copolymer thermoplastic resin (A2): bisphenol A type polycarbonate having a refractive index of 1.584 Thermoplastic resin (A3): polyethylene terephthalate composed of terephthalic acid and ethylene glycol and having a refractive index of 1.575 Thermoplastic resin (A4): 39.9 [mol%] of isophthalic acid, 8.9 [mol%] of dodecanedicarboxylic acid (above dicarboxylic acid component), hexamethylene diamine 26.1
[Mole%], 25.1 [Mole%] bis (3-methyl-4-amino-cyclohexyl) methane (above the diamine component), and an alicyclic transparent nylon having a refractive index of 1.535

The number average molecular weight and the melt viscosity of these thermoplastic resins were measured. The results are summarized in Table 1. The number average molecular weight was determined by gel permeation chromatography manufactured by Tosoh Corporation using chloroform as a solvent in terms of standard polystyrene. The melt viscosity C was measured at 270 ° C. and a shear rate of 1200 (1/1) using an orifice having a diameter of 1 mm and L / D = 10 using a Capillograph manufactured by Toyo Seiki Seisaku-sho.
(Seconds) and the value when extruded was measured.

[Production Example 1] [Synthesis of polyester resin (B1)] Phthalic acid component 30
[Mol%] and an isophthalic acid component 70 [mol%], an acid component (dicarboxylic acid component), trimethylolpropane 1.5 [mol%] and ethylene glycol 9
Using an alcohol component (diol component) composed of 8.5 [mol%] and 500 ppm of an antimony trioxide catalyst,
Polyester resin (B
1) was obtained. Table 2 shows the number average molecular weight, melt viscosity, and refractive index of the polyester resin (B1). The number average molecular weight and the melt viscosity were determined in the same manner as in the above reference example.
As for the refractive index, a thermoplastic resin and a polyester resin were each independently heated to soften or melt at a temperature at which molding is possible, press-molded, rapidly cooled and solidified to form a thin flat plate. This was measured using an Atago Abbe refractometer according to JIS K71.
05. Table 2 shows the results.

[Production Examples 2 to 5] [Synthesis of Polyester Resins (B2) to (B5)] Polyester resins (B2) to (B5) having compositions shown in Table 2 using the same method as in Production Example 1. And the number average molecular weight, melt viscosity and refractive index thereof were determined in the same manner as in Production Example 1. Table 2 shows the results.

Example 1 Polyester resin (B1) 1
0 parts, 90 parts of the thermoplastic resin (A1) and 0.1 parts of triethylphosphine are mixed and supplied to a twin screw extruder.
The polyester resin composition shown in Table 3 was obtained by melt-kneading at 260 ° C. The transparency of the obtained polyester resin composition was evaluated, and the melt viscosity and the Iz impact strength were measured. Table 3 shows the results. The Iz impact strength is A
It was measured according to STM D256. The test pieces were molded using an injection molding machine at a cylinder temperature of 260 ° C. and a mold temperature of 10 ° C. The Iz impact strength was measured for two weeks after the molding. The polyester (A) was observed by observing the injection-molded test piece with a transmission electron microscope.
It can be confirmed that the polyester resin (B1) particles are dispersed in the continuous phase of 1), and the particle size distribution is 0.03.
The range was from μm to 2.0 μm. The transparency was evaluated by using an injection molding machine, preparing a 1.6 mm thick plate-like test piece at a cylinder temperature of 260 ° C. and a mold temperature of 10 ° C., and measuring the haze value visually. A haze value of less than 10 was defined as transparent (symbol in the table:）), and a haze value of 10 or more was defined as opaque (symbol in the table; ×). The melt viscosity was determined in the same manner as in Reference Example.

[Examples 2 to 4] Polyester resins (B1) and (B2) were prepared in the same manner as in Example 1 at the ratios shown in Table 3.
And the thermoplastic resins (A1) to (A4) shown in Table 1 were melt-kneaded. In the same manner as in Example 1, while evaluating the transparency of the obtained polyester resin composition, the melt viscosity C,
The Iz impact strength was measured. Table 3 shows the results. In addition, by observation of the injection-molded test specimen with a transmission electron microscope,
It can be confirmed that each polyester resin particle is dispersed in the continuous phase of each thermoplastic resin, and the particle size distribution is 0.1%.
The range was from 03 μm to 2.0 μm.

Comparative Examples 1 to 3 Polyester resins (B3) to (B5) at the ratios shown in Table 3 in the same manner as in Example 1.
And the thermoplastic resin (A3) shown in Table 1 were melt-kneaded. In the same manner as in Example 1, the transparency of the obtained polyester resin composition was evaluated, and the melt viscosity C and the Iz impact strength were measured. Table 3 shows the results.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

[Table 3]

As described above, the thermoplastic resin compositions obtained in Examples 1 to 4 have excellent transparency, high fluidity,
Also, the mechanical strength (Iz impact strength) was excellent. On the other hand, the thermoplastic resin composition of Comparative Example 1 comprising the polyester resin (B3) having no ethylene glycol in the structural unit and the thermoplastic resin (A3) has a refractive index difference | a−b | of 0.029. The fluidity and strength were excellent, but the transparency was low. The thermoplastic resin composition of Comparative Example 2 using the polyester resin (B4) having a number average molecular weight of 2000 had good fluidity but low mechanical strength. Also,
The thermoplastic resin composition of Comparative Example 3 using the polyester resin (B5) having a melt viscosity exceeding 200 Pa · s had excellent mechanical strength but low fluidity.

[0044]

As described above, according to the present invention, mechanical properties, particularly impact resistance and toughness, are high and excellent in fluidity, and bleed out, heat resistance and durability are improved. An excellent thermoplastic resin composition can be obtained at low cost. The thermoplastic resin composition of the present invention, in particular,
It is extremely useful as an injection molding material used for thin-walled molded products such as strips, panels, cases and cups, and especially for large-sized molded products such as trash boxes and pallets using recycled polyester.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor: Ken Nii 20-1 Miyukicho, Otake City, Hiroshima Prefecture F-term in Central Research Laboratory, Mitsubishi Rayon Co., Ltd. 4J002 CF032 CF042 CF082 CF112 CF182 CG011 CG021 CL011 CL031 CL051 FD010 FD050 GC00 GG00 GT00

Claims (4)

[Claims] 1. A thermoplastic resin (A) having a number average molecular weight of 18,000 or more and a melt viscosity at 270 ° C. of 200 Pa · s or more, 70 to 99% by mass, a number average molecular weight of 3,000 or more, and A polyester resin (B) having a melt viscosity at 270 ° C. of less than 200 Pa · s is 1 to 30% by mass, and the polyester resin (B) has an aromatic dicarboxylic acid unit of 80 to 100. [Mol%], comprising an acid component containing an ethylene glycol unit and an alcohol component containing an ethylene glycol unit, and a mole fraction of a dibasic acid unit other than an aromatic dicarboxylic acid unit in the acid component, and a mole fraction other than an ethylene glycol unit in the alcohol component. The sum of the mole fraction of the diacid-base unit is 50 [mol%] or less, and the mole fraction of the polyvalent component contained in the acid component and the polyvalent component contained in the alcohol component The sum of the mole fractions is 0.05 to 3 [mol%], and the refractive index a of the thermoplastic resin (A) and the refractive index b of the polyester resin (B) satisfy the following formula 1, and A thermoplastic resin composition characterized in that the melt viscosity Ca (Pa · s) of the thermoplastic resin (A) and the melt viscosity Cb of the polyester resin (B) satisfy the following formula 2. | Ab− ≦ 0.029 (Equation 1) Cb <0.4 × Ca (Equation 2) (However, in Equation 2, the melt viscosities Ca and Cb are 27
It is a value measured at 0 ° C. and a shear rate of 1200 (1 / second). ) 2. The polyester resin (B) according to claim 1, wherein at least 40 [mol%] of the acid component is an isophthalic acid unit and / or a phthalic acid unit.
5. The thermoplastic resin composition according to item 1. 3. The thermoplastic resin (A) and the polyester resin (B) are incompatible, and the polyester resin (B) particles having a particle size of 0.02 to 5 μm are contained in the continuous phase of the thermoplastic resin (A). The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition is dispersed. 4. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin (A) is a polycarbonate resin and / or a polyamide resin.