JP3105366B2 - Method for imparting release property to molded article of thermoplastic polyester resin using mold release agent for molding in synthetic resin mold and thermoplastic polyester resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for imparting releasability to a molded article of a thermoplastic polyester resin using a release agent for molding a synthetic resin mold, and to a thermoplastic polyester resin composition.

[0002]

2. Description of the Related Art Conventionally, as a release agent for molding in a synthetic resin mold, 1) waxes such as montan wax, carnauba wax, beeswax, petroleum wax, and modified products thereof (JP-A-54-4742, JP-A-60-18846
3) 2) Synthetic ester waxes (JP-A-55-86)
837), 3) Metallic soaps of higher fatty acids (JP-B-54)
4742), 4) Polygen-polyvinyl graft copolymer (JP-A-63-54462), 5) Siloxane oils such as polydimethylsiloxane and polyphenylsiloxane (JP-A-64-69306), 6) Polyfluoroethylene Fluoropolymers, etc., have been proposed, and as a method of imparting releasability to a molded article in a synthetic resin mold using these, kneading them into a synthetic resin or applying them to the mold surface is performed. ing.

However, the above-mentioned release agents 1) to 4) include:
Since heat resistance is inferior, it tends to be thermally decomposed when kneaded with a synthetic resin, and there is a disadvantage that gaseous substances and carbides generated thereby contaminate the surface of the mold and the surface of the molded product. Such disadvantages are polyethylene terephthalate melt molded at high temperatures,
This is remarkable in in-mold molding of a thermoplastic polyester resin such as polybutylene terephthalate. 5),
The release agent of 6) has excellent heat resistance, but has poor kneading properties with the synthetic resin and undergoes phase separation. There is a disadvantage that surface contamination and the like occur. Therefore, its use is limited to mold surface application.

[0004]

The problem to be solved by the present invention is that a conventional method for imparting release properties to a molded article in a synthetic resin mold using a mold release agent for molding in a synthetic resin mold has a problem in that the heat resistance is low. It is inferior and contaminates the surface of a mold or a molded product, or is poor in kneading with a synthetic resin and causes various obstacles due to phase separation.

[0005]

Means for Solving the Problems Thus, the present inventors have
As a result of intensive studies to solve the above-mentioned problems, a polysiloxane-polyvinyl graft copolymer having a specific structure obtained by graft-polymerizing a vinyl monomer to a polyorganosiloxane was used as a mold release agent for molding in a synthetic resin mold. It has been found that it is correct and suitable to incorporate a mold release agent for in-mold molding at a predetermined ratio to the thermoplastic polyester resin and carry out in-mold molding.

That is, the present invention relates to a mold for molding in a synthetic resin mold comprising a polysiloxane-polyvinyl graft copolymer mainly formed of a siloxane unit represented by the following formula 1 and a siloxane unit represented by the following formula 2. A method for imparting releasability to a molded article of a thermoplastic polyester resin, wherein the mold agent is contained in a ratio of 0.07 to 3 parts by weight with respect to 100 parts by weight of a thermoplastic polyester resin and molded in a mold. And a thermoplastic polyester resin composition comprising 0.07 to 1 part by weight of the release agent for molding in a synthetic resin mold per 100 parts by weight of the thermoplastic polyester resin.

[0007]

(Equation 1)

[0008]

(Equation 2)

[In the formulas 1 and 2, R ^{1 to} R ³ : a hydrocarbon group having a carbon atom directly bonded to a silicon atom and having the same or different, unsubstituted or substituted radically non-polymerizable group. A: a divalent organic group having a carbon atom directly bonded to a silicon atom and linked to B. B: Vinyl polymer block. ]

In the formulas 1 and 2, R ^{1 to} R ³ are unsubstituted or substituted, non-radical polymerizable hydrocarbon groups having a carbon atom directly bonded to a silicon atom. Among these, examples of the unsubstituted hydrocarbon group include an alkyl group, a cycloalkyl group, an aryl group, an alkylaryl group, an aralkyl group and the like. Four alkyl groups or phenyl groups are advantageously chosen. Examples of the substituted hydrocarbon group include a substituted hydrocarbon group having a halogen, an epoxy group, a cyano group, a ureido group, and the like. Among them, a γ-glycidoxypropyl group and a β- (3,4- Epoxy) cyclohexylethyl, γ-chloropropyl, trifluoropropyl and the like are advantageously selected. These unsubstituted hydrocarbon groups and substituted hydrocarbon groups can be in any ratio.

In Formula 2, A is a divalent organic group having a carbon atom directly bonded to a silicon atom and being bonded to B. A is important as a group connecting the vinyl polymer block to the polyorganosiloxane. Examples of A include an ethylene group, a propylene group, a 3-oxo-4-oxa-1,7-heptanediyl group, a 2-methyl-3-oxo-4-oxa-1,7-heptanediyl group, and a trimethylenethioxy group. And the like.

In the formula 2, B is a vinyl polymer block obtained by graft-polymerizing a vinyl monomer. In B, a vinyl monomer containing a vinyl monomer having a fluorine substituent is graft-polymerized in addition to a vinyl polymer block obtained by graft-polymerizing a vinyl monomer having no fluorine substituent. And the resulting vinyl polymer block. And here, the vinyl polymer block obtained by graft-polymerizing a vinyl monomer containing a vinyl monomer having a fluorine substituent is obtained by graft-polymerizing a vinyl monomer having a fluorine substituent. In addition to the vinyl polymer block, a vinyl polymer block obtained by graft-polymerizing a vinyl monomer having a fluorine substituent and a vinyl monomer having no fluorine substituent is included (hereinafter, these are referred to simply as Vinyl polymer block).

Examples of the vinyl monomer having no fluorine substituent include: 1) alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, and cyclohexyl methacrylate;
2) alkyl acrylates such as methyl acrylate, ethyl acrylate and butyl acrylate; 3) aromatic vinyl monomers such as styrene and α-methyl styrene; 4)
Vinyl benzoate, vinyl esters such as vinyl acetate, and the like, among which aromatic vinyl monomers,
Those containing at least 90% by weight of one or more selected from alkyl (meth) acrylate and acrylonitrile, particularly styrene, methyl (meth) acrylate and ethyl (meth) acrylate are preferred.

Examples of the vinyl monomer having a fluorine substituent include 1) 1H, 1H, 11H-eicosafluoroundecyl acrylate, 1H, 1H-heptafluorobutyl acrylate, hexafluoroisopropyl acrylate, 1H, 1H Fluoroalkyl acrylates such as 1,5H-octafluoropentyl acrylate, 1H, 1H-pentadecafluorooctyl acrylate, 2,2,3,3-tetrafluoropropyl acrylate, and 2,2,2-trifluoroethyl acrylate;
2) 1H, 1H, 11H-eicosafluoroundecyl methacrylate, 1H, 1H-heptafluorobutyl methacrylate, hexafluoroisopropyl methacrylate, 1H, 1H, 5H-octafluoropentyl methacrylate, 1H, 1H-pentadecafluorooctyl methacrylate Fluoroalkyl methacrylates such as 2,2,3,3,3-pentafluoropropyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate and 2,2,2-trifluoroethyl methacrylate; 2,3,3-tetrafluoropropyl-2- (trifluoromethyl) propenoate, 2,
Α-fluoroalkylacrylic acid esters such as 2,2-trifluoroethyl-2- (trifluoromethyl) propenoate, 4) α-fluoroalkylvinylcarboxylic acid esters such as 1- (trifluoromethyl) vinyl acetate, 5) vinyl fluorocarboxylates such as vinyl trifluoroacetate; 6) fluoro-substituted styrenes such as 3-fluorostyrene and 4-fluorostyrene; 7) α- such as α-trifluoromethylstyrene.
Examples thereof include fluoroalkylstyrenes, among which those having no fluorine substituent or fluoroalkyl group near the vinyl group are preferable. This is because the influence of the electron absorption of fluorine and the steric effect due to the fluoroalkyl group is small, and the graft polymerization is excellent. When using a vinyl monomer having no fluorine substituent and a vinyl monomer having a fluorine substituent as the vinyl monomer, each having a fluorine substituent, an aromatic vinyl monomer, vinyl carboxylate, 1 selected from alkyl (meth) acrylates
Those containing 2% by weight or more of two or more species are preferred.

Next, a method for producing the polysiloxane-polyvinyl graft copolymer in the present invention will be described.
First, a compound capable of forming a silanol group by hydrolysis (hereinafter referred to as a silanol group-forming compound) is hydrolyzed in an aqueous medium in the presence of a hydrolysis catalyst such as an acid or an alkali to form a silanol compound. Next, the silanol compound is polycondensed in the presence of a polycondensation catalyst such as an inorganic acid or an organic acid to form an aqueous emulsion of polysiloxane. In order to reduce the average particle size of the aqueous emulsion and form a stable aqueous emulsion of polysiloxane, a surfactant may be appropriately used in a hydrolysis reaction system of a silanol group-forming compound or a polycondensation reaction system of a silanol compound. it can. Finally, a vinyl monomer and a radical polymerization catalyst are added to the aqueous emulsion of polysiloxane to perform graft polymerization, and a vinyl polymer block is introduced into the polysiloxane.

Examples of the silanol group-forming compound include various alkoxysilanes, chlorosilanes, hydrogensilanes, acyloxysilanes, cyclosiloxane compounds and the like. In the present invention, a silanol group-forming compound in which two silanol groups are formed by hydrolysis is used as a main raw material. Further, in the present invention, as described above, in order to introduce a vinyl polymer block into polysiloxane, as a silanol group-forming compound, a silanol group-forming compound having a functional group such as a radical polymerizable group or a thiol group in a molecule. Is used.

The silanol group-forming compound which forms the siloxane unit represented by the formula 1 includes: 1) a silane compound such as dimethyldimethoxysilane, dimethyldichlorosilane, dimethyldihydrogensilane, or dimethylchlorosilanol; ) Siloxane compounds such as hexamethyldisiloxane and octamethylcyclotetrasiloxane; 3) γ-glycidoxypropyl-methyl-dimethoxysilane; γ-ureidopropyl-methyl-dimethoxysilane; N, N-dimethylaminopropyl-methyl. Silane compounds having a hydrocarbon group substituted by a polar group such as dimethoxysilane; and the like.

Examples of the silanol group-forming compound that forms the siloxane unit represented by the formula 2 include methacryloyloxypropyl methyl dimethoxysilane,
Examples include silane compounds such as vinyl methyl dimethoxy silane, aryl methyl dimethoxy silane, and mercaptopropyl methyl dimethoxy silane.

As described above, in the present invention, a polysiloxane-polyvinyl graft copolymer is produced by using, as a main raw material, a silanol group-forming compound capable of forming two silanol groups by hydrolysis. For the purpose of controlling the molecular weight of the polysiloxane obtained by the condensation polymerization of the silanol compound and controlling the structure of the terminal group of the polysiloxane, a silanol group-forming compound that forms one silanol group by hydrolysis is appropriately used. Can be. The use ratio of such a silanol group-forming compound is usually 2 mol% or less, preferably 1 mol% or less as a siloxane unit in all the silanol group-forming compounds.

Examples of the silanol group-forming compound in which one silanol group is formed by hydrolysis include: 1)
Trimethylmethoxysilane, trimethylchlorosilane,
Silane compounds such as trimethyl hydrogen silane,
2) siloxane compounds such as hexamethyldisiloxane,
3) silane compounds such as γ-glycidoxypropyl dimethyl methoxysilane, γ-ureidopropyl dimethyl methoxysilane, N, N-dimethylaminopropyl dimethyl methoxysilane, 4) methacryloyloxypropyl dimethyl methoxy And silane compounds such as silane, vinyl dimethyl methoxy silane, aryl dimethyl methoxy silane, and mercaptopropyl dimethyl methoxy silane.

In order to produce a polysiloxane-polyvinyl graft copolymer, as described above, a silanol group-forming compound is hydrolyzed in an aqueous medium, and the resulting silanol compound is polycondensed to obtain an aqueous emulsion of polysiloxane. Get. The aqueous medium used here is 30% by weight of water.
Above, preferably a homogeneous solvent containing at least 90% by weight. Examples of the solvent that can be used in combination with water include water-soluble solvents such as methanol, ethanol, isopropanol, acetone, and tetrahydrofuran.

The graft polymerization is carried out by adding a radical polymerization catalyst and a vinyl monomer to an aqueous polysiloxane emulsion and stirring the mixture under an inert gas atmosphere. The reaction at this time can be carried out at a temperature from room temperature to the boiling point of the vinyl monomer used.

Thus, an aqueous emulsion of a polysiloxane-polyvinyl graft copolymer in which a vinyl monomer is graft-polymerized to the polysiloxane is obtained. Although the present invention is not particularly limited as to the method for separating the polysiloxane-polyvinyl graft copolymer from the aqueous emulsion, 1) sodium chloride,
A method of adding an alkali metal salt such as potassium chloride, potassium bromide or sodium sulfate, or 2) adding a water-soluble alkaline earth metal salt such as calcium chloride or magnesium chloride and salting out and separating the polysiloxane-polyvinyl graft copolymer. It is advantageous. The salts of the above 1) and 2) are any one or 2
Seeds or more may be added as they are or as a concentrated aqueous solution. If necessary, the product obtained by salting out is further centrifuged, separated by filtration, removed of salts by washing with water or the like, and dried.

In the present invention, the ratio of the siloxane unit represented by the formula (2) to the total siloxane units among the siloxane units forming the polysiloxane-polyvinyl graft copolymer is not particularly limited, but the ratio is usually 10 mol. % Or less, preferably 4 mol% or less.
The polysiloxane moiety in the polysiloxane-polyvinyl graft copolymer has a molecular weight of 7000 to 50.
0000 is preferable, and 20,000 to 100,000
Are more preferred. The proportion of the vinyl polymer block in the polysiloxane-polyvinyl graft copolymer varies depending on the type of the vinyl polymer block and the synthetic resin to be applied, but is preferably 1 to 80% by weight from the viewpoint of physical properties. More preferably, it is 10 to 50% by weight.

The polysiloxane-polyvinyl graft copolymer is used as a mold release agent for molding in a synthetic resin mold, and polyethylene terephthalate, polyethylene terephthalate, or the like is used as a thermoplastic polyester resin for imparting mold releasability to a molded product obtained by molding in a mold. Examples include polybutylene terephthalate and polyethylene naphthalenedicarboxylate.

In order to use a release agent for in-mold molding of a synthetic resin to impart releasability to a molded article of a thermoplastic polyester resin obtained by in-mold molding, it is necessary to use a polysiloxane-polyvinyl graft as the release agent. The copolymer is contained in an amount of 0.07 to 3 parts by weight, preferably 0.7 parts by weight or less, based on 100 parts by weight of the thermoplastic polyester resin. The present invention is not particularly limited with respect to the method of including the release agent in the synthetic resin. As such a method, 1) a method in which a release agent is added to and mixed with a thermoplastic polyester resin, and if necessary, melt kneading, 2) a master product of a thermoplastic polyester resin containing a high concentration of the release agent is prepared. In advance,
There is a method in which this is added to a thermoplastic polyester resin and diluted so as to have a predetermined content ratio. In the present invention, by blending the release agent with the thermoplastic polyester resin in this way, a thermoplastic polyester resin composition having improved release properties and suitable for in-mold molding can be obtained. Since the generation of gas during molding is suppressed, they are also excellent in the effect of preventing mold contamination. The amount of the release agent is preferably 0.07 to 1 part by weight, more preferably 0.07 to 100 parts by weight of the thermoplastic polyester resin.
When the amount is set to 0.7 parts by weight, the releasing effect and the effect of preventing mold contamination can be more sufficiently obtained.

A known kneading process can be applied to prepare a thermoplastic polyester resin composition containing a release agent for in-mold molding of a synthetic resin comprising a polysiloxane-polyvinyl graft copolymer. As such a kneading process, there is a process using a mill, a calender, a kneader, an extruder, or the like. The kneading temperature is not lower than the melting point of the thermoplastic polyester resin to be applied, generally from 160 to 30.
0 ° C.

The present invention is not particularly limited as to the in-mold molding method to be employed, but the injection molding method is advantageous.

In the present invention, in order to impart a high degree of mold releasability to a thermoplastic polyester resin molded product obtained by molding in a mold, a polysiloxane-polyvinyl graft copolymer as a mold release agent must be melted. Temperature 50-260
It is preferable to use one having a temperature of ° C. When an injection molding method is applied as an in-mold molding method to obtain a molded product, a polysiloxane-polyvinyl graft copolymer as a release agent is used at a temperature equal to or higher than the temperature of the mold to be applied and equal to or lower than the melting point of the thermoplastic synthetic resin. It is preferable to use one having a melting temperature of

[0030]

EXAMPLES In order to make the constitution and effect of the present invention more concrete, a synthesis example of a polysiloxane-polyvinyl graft copolymer will be described as Test Section 1 and an in-mold molding example will be described as Test Section 2. In each example, “part” represents “part by weight” and “%” represents “% by weight”. Various physical properties and characteristics in Test Category 1 were measured or evaluated as follows.

The molecular weight of the polysiloxane portion in the polysiloxane-polyvinyl graft copolymer A part of the aqueous emulsion of the polysiloxane before graft polymerization of the vinyl monomer was taken out, tetrahydrofuran was added thereto, and the mixture was shaken and stirred. The polysiloxane was extracted. In this case, an appropriate amount of calcium chloride was added as needed in order to enhance the effect of extracting the polysiloxane from the aqueous emulsion. Tetrahydrofuran was distilled off from the obtained polysiloxane extract under reduced pressure to obtain a polysiloxane for molecular weight measurement.
The molecular weight (in terms of polystyrene) was measured using GPC.

Melting temperature The sample was placed in a melting point measuring apparatus, heated and adjusted at a rate of 1 ° C./min from the point at which the sample began to melt, and the temperature at which the entire sample was melted was measured. This was taken as the melting temperature.

Test Category 1 (Synthesis Example of Polysiloxane-Polyvinyl Graft Copolymer) Synthesis Example 1 100.6 g of octamethylcyclotetrasiloxane
(0.34 mol), 1.6 g of hexamethyldisiloxane
(10 mmol), 2.0 g (8.8 mmol) of γ-methacryloxypropylmethyldimethoxysilane, 1.1 g of dodecylbenzenesulfonic acid, and 315 g of ion-exchanged water
And dispersed with a homomixer. Next, this was passed through a homogenizer and uniformly emulsified to obtain 421 g of an aqueous emulsion of a silanol compound. This was charged into a flask and subjected to condensation polymerization at 80 ° C. for 5 hours. Thereafter, the mixture was gradually cooled for 16 hours, neutralized with a saturated aqueous solution of sodium carbonate, and filtered to obtain an aqueous emulsion of polysiloxane. The aqueous emulsion of polysiloxane obtained here was charged into another flask, and 1.6 g of potassium persulfate and 400 g of ion-exchanged water were added.
And heated to 70 ° C. After replacing the reaction system with nitrogen,
45 g (0.43 mol) of styrene was added dropwise over 2 hours. After completion of the dropwise addition, the mixture was heated to 80 ° C. and aged for 4 hours.
The mixture was gradually cooled to ℃ and filtered. 10. Calcium chloride in the filtrate
After adding 6 g for salting out, the mixture was filtered, washed with 1000 g of warm water, and dried. A white powder was obtained. The polysiloxane-polyvinyl graft copolymer as a white powder thus obtained had a molecular weight of the polysiloxane portion of about 11,000.

Synthesis Example 2 97.7 g of octamethylcyclotetrasiloxane (0.
33 mol), 4.3 g (19.6 mmol) of γ-glycidoxypropylmethyldimethoxysilane, 7.6 g of γ-methacryloxypropylmethyldimethoxysilane (3 g)
2.4 mmol) to obtain a mixed siloxane monomer. This was added to 300 g of ion-exchanged water in which 1.0 g of dodecylbenzenesulfonic acid was dissolved, dispersed by a homomixer, and further uniformly emulsified by a homogenizer to obtain an aqueous emulsion of a silanol compound. Next, 31 g of dodecylbenzene sulfonic acid and 217 g of ion-exchanged water were charged into a flask and dissolved well.
The temperature was raised to 5 ° C., and the aqueous emulsion of the silanol compound was added dropwise over 2 hours. After dropping is complete,
Aged for hours. After aging, the mixture was cooled to room temperature and neutralized with sodium carbonate to obtain an aqueous emulsion of polysiloxane. 483 g of ion-exchanged water and 1.5 g of potassium persulfate were dissolved in the aqueous emulsion of polysiloxane obtained here, transferred to another flask, and heated to 70 ° C. while flowing nitrogen. And 100 g of styrene (0.96 mol)
Was slowly added dropwise. After completion of the dropwise addition, the mixture was aged for 3 hours, and a white powder was obtained in the same manner as in Synthesis Example 1 using calcium chloride. The polysiloxane-polyvinyl graft copolymer as a white powder thus obtained had a molecular weight of about 67000 in the polysiloxane portion.

The contents of the polysiloxane-polyvinyl graft copolymers obtained in Synthesis Examples 1 and 2 were calculated from the charge ratio of the raw materials for synthesis, and the results are shown in Table 1.

[0036]

[Table 1]

In Table 1, * 1: siloxane unit represented by formula 1 / siloxane unit represented by formula 2

Test Category 2 (Example of In-Mold Molding) Examples 1-4, Comparative Examples 1-4 (Examples of Injection Molding) Commercially available polybutylene terephthalate resin (trade name) After mixing with Novador, intrinsic viscosity [η]: 1.10 dl / g, manufactured by Mitsubishi Kasei Co., Ltd.), the mixture was kneaded and extruded with an extruder to obtain pellets. Injection molding was performed using the pellets, and the physical properties of the molded product, resin fluidity during molding, mold release properties, and generated gas were measured or evaluated. The results are shown in Table 2.

Physical property measuring method Tensile test: conforming to ASTM D638 Izod impact strength: conforming to ASTM D256

Flowability measurement method Spiral flow length measurement test mold (cavity: width 6 mm)
× thickness 2 mm), molding was performed under the conditions of a cylinder temperature of 260 ° C., an injection pressure of 1150 kg / cm ² , and a mold temperature of 80 ° C., and the fluidity was evaluated from the flow length (molded product length).

Evaluating method of mold releasability A screw-type injection molding machine having a diameter of 32 mm was used to measure a cavity length of 8 mm.
Using a lattice mold of 0 mm x 80 mm x 4 mm thickness, 2.5 degree reverse taper, cylinder temperature 260 ° C, injection pressure 115
Molding is performed by changing the molding cycle (mainly the cooling time) under the conditions of 0 kg / cm ² and the mold temperature of 80 ° C, and the degree of deformation of the protrusion of the protruding pin on the molded product at the time of mold release is an index of mold release properties. And Judgment of releasability ○: No deformation is observed △: Slight deformation ×: Remarkable deformation XX: Poor protrusion

Method of Evaluating Gas Generated During Molding Dirt on the mold when 100 shots were continuously molded at a cylinder temperature of 260 ° C. and a mold temperature of 50 ° C. using a gas evaluation mold with a screw type injection molding machine having a diameter of 32 mm. Was used as an index of the amount of generated gas. Judgment of generated gas ○: extremely small amount of gas △: small amount of gas ×: large amount of gas ××: extremely large amount of gas

[0043]

[Table 2]

In Table 2, added amount: 100 parts by weight of polybutylene terephthalate resin, parts by weight of release agent or compounding agent Compounding agent X: pentabromobenzyl polyacrylate Compounding agent Y: antimony trioxide R-1: molecular weight 470 A certain paraffin wax R-2: a polyolefin wax having a molecular weight of 900 R-3: a polyolefin wax obtained by copolymerizing an α-olefin having a molecular weight of 1,000 R-4: a polyolefin copolymer obtained by copolymerizing an α-olefin having a molecular weight of 4000 wax

[0045]

As is clear from the above, the present invention described above has excellent mold release properties which do not impair the surface of a mold or a molded product and which does not cause any trouble in the molding operation. There is an effect that it can be applied to a molded article in a polyester resin mold.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI B29K 67:00 (58) Fields investigated (Int.Cl. ⁷ , DB name) C08F 283/12 C08L 67/00-67/04

Claims (6)

(57) [Claims] 1. A mold release agent for molding in a synthetic resin mold comprising a polysiloxane-polyvinyl graft copolymer mainly formed from a siloxane unit represented by the following formula 1 and a siloxane unit represented by the following formula 2 A method for imparting mold releasability to a molded article of a thermoplastic polyester resin, wherein the molded article is molded in a mold by containing 0.07 to 3 parts by weight with respect to 100 parts by weight of a thermoplastic polyester resin. (Equation 1) (Equation 2) [In the formulas 1 and 2, R ^{1 to} R ³ : a hydrocarbon group having a carbon atom directly bonded to a silicon atom and having the same or different, unsubstituted or substituted, radically non-polymerizable group. A: a divalent organic group having a carbon atom directly bonded to a silicon atom and linked to B. B: Vinyl polymer block. ] 2. A polymer obtained by graft polymerization of B in the formula 2 with a vinyl monomer containing 90% by weight or more of one or more selected from aromatic vinyl monomers, alkyl (meth) acrylates and acrylonitrile. The method for imparting releasability to a molded article of a thermoplastic polyester resin according to claim 1, which is the obtained vinyl polymer block. 3. B of the formula 2 contains 2% by weight or more of one or more selected from aromatic vinyl monomers, vinyl carboxylate and alkyl (meth) acrylate each having a fluorine substituent. The method for imparting releasability to a molded article of a thermoplastic polyester resin according to claim 1, which is a vinyl polymer block obtained by graft-polymerizing a vinyl monomer. 4. The method according to claim 1, wherein the in-mold molding is injection molding.
Or the method for imparting releasability to a molded article of a thermoplastic polyester resin mold according to item 3. 5. A thermoplastic polyester resin composition comprising 0.07 to 1 part by weight of the release agent for in-mold molding of a synthetic resin according to claim 1, 2 or 3 based on 100 parts by weight of the thermoplastic polyester resin. . 6. The thermoplastic polyester resin composition according to claim 5, wherein the compounding amount of the release agent for molding in a synthetic resin mold is 0.07 to 0.7 parts by weight.