KR20190037496A - Polyester resin composition and molding produced from the same - Google Patents

Abstract

The present invention relates to a polyester resin composition and a molded article manufactured from the same. More specifically, the polyester resin composition has excellent hydrolysis resistance properties, fluidity, and impact resistance and can be easily molded into various molded articles by injection molding or extrusion molding. The molded article manufactured by the polyester resin composition according to the present invention has improved hydrolysis resistance properties and also has excellent fluidity, thereby being able to be applied to the manufacture of various products such as connectors for automobiles, electric and electronic appliances and the like having a complicated structure.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a polyester resin composition,

The present invention relates to a polyester resin composition and a molded article produced therefrom.

Generally, polybutylene terephthalate (PBT) resins are excellent in heat resistance, chemical resistance, electrical properties, mechanical strength and molding processability, and are used in automobiles, electric and electronic parts, and the like. Particularly, PBT resin is widely used for electric and electronic applications because of its excellent electrical properties such as dielectric breakdown strength and arc resistance due to low water absorption. It is widely used for electric parts with complicated structures such as various connectors, capacitors, And it has been used as automotive component material requiring high electrical characteristics such as spark plugs.

As parts for automobiles become miniaturized, the structure becomes complicated and there is a problem of cracking of the lance. When the fluidity is low, there is a possibility of molding problems, so it is required to develop a shockproof, high-dynamic PBT resin. The PBT resin is decomposed into hydroxyl and carboxyl groups by contact with an acid or an aqueous base solution and under hydrothermal conditions under high temperature and high humidity. Such hydrolysis continuously produces a carboxyl group, promotes the hydrolysis of the PBT resin, and results in a very rapid decrease in tensile and flexural strength elongation, elastic modulus, impact strength, and the like.

Korean Patent Laid-Open Publication No. 2006-0116072 proposes a method of solid-phase polymerization of PBT resin prepared by adding carbodiimide to PBT polymer in the prior art, but the viscosity is increased due to solid-state polymerization, There is a disadvantage in cost increase due to the increase in cost.

Korean Patent Publication No. 2007-0087859 proposes an impact-resistant and hydrolysis-resistant technology by prescribing Et-nBA-GMA copolymer and carbodiimide hydrolysis inhibitor in PBT resin. However, there is a disadvantage that breaking strength may be drastically lowered after the moisture-dissipating test, and the lance portion of the connector may be broken.

Therefore, development of a PBT resin which can improve the hydrolysis resistance and prevent the hydrolysis of the PBT resin and at the same time enhance the impact resistance and the flowability is desired.

Disclosed is a PBT resin composition which is improved in hydrolysis resistance and which is low in strength and elongation deterioration even in a high temperature and high humidity environment, secures impact resistance and high flowability, and is advantageous in manufacturing a complex product having a complicated structure and small size.

As a preferred embodiment according to the present invention, a polybutylene terephthalate resin; 5 to 30 parts by weight of a thermoplastic polyetherester elastomer (TPEE) relative to 100 parts by weight of the polybutylene terephthalate resin; 3 to 20 parts by weight of an impact modifier; And 1 to 3 parts by weight of a hydrolysis inhibitor containing a carbodiimide-based compound.

The polybutylene terephthalate resin may have an intrinsic viscosity of 0.6 dl / g to 1.8 dl / g.

The thermoplastic polyetherester elastomer may be characterized in that the surface hardness is shore 39d to 72d.

The impact modifier may include glycidyl methacrylate.

The carbodiimide compound may be N, N'-di-o-tolylcarbodiimide, N, N'-diphenylcarbodiimide, N, N'- , N, N'-di-2,6-diisopropylphenylcarbodiimide, N, N'-di-2-naphthylcarbodiimide, Di-tert-butylphenylcarbodiimide, N, N'-di-p-nitrophenylcarbodiimide, N, N'-di- N, N'-di-p-toluylcarbodiimide, N, N'-di-p-toluylcarbodiimide, Bis-dicyclohexylcarbodiimide, ethylene-bis-diphenylcarbodiimide, benzene-2-dicyclohexylcarbodiimide, Diisocyanato-1,3,5-tris (1-methylethyl) homopolymer, 2,4-diisocyanato-1,3,5-tris (1-methylethyl) - diisop And copolymers of polyisocyanate and polyisocyanate and copolymers of polyisocyanate and isophthalic acid.

As another preferred embodiment according to the present invention, there is provided a molded article made of the above-mentioned polyester resin composition.

The molded product may have a tensile elongation of 90% or more, a tensile strength retention ratio of 90% or more, a fluidity of 30 g / 10 min or more, and a bending strength retention ratio of 90% or more after a pressure cooker test of 144 hours.

According to the present invention, it is possible to provide a polyester resin composition which has excellent moisture resistance, flowability and impact resistance and can be easily molded into various molded articles by injection molding or extrusion molding.

In addition, the molded article made from the polyester resin composition according to the present invention can be applied to the manufacture of various products such as connectors for automobiles, electrical appliances and the like, which have a complicated structure, because the moisture-decomposing performance is improved and the fluidity is excellent.

A preferred embodiment of the present invention is a polybutylene terephthalate resin; 5 to 30 parts by weight of a thermoplastic polyetherester elastomer (TPEE) relative to 100 parts by weight of the polybutylene terephthalate resin; 3 to 20 parts by weight of an impact modifier; And 1 to 3 parts by weight of a hydrolysis inhibitor containing a carbodiimide-based compound.

Hereinafter, the present invention will be described in more detail.

[ Polybutylene terephthalate (PBT) resin]

The polybutylene terephthalate resin may be prepared by direct esterification reaction or transesterification reaction through 1,4-butanediol and dimethyl terephthalate. The polybutylene terephthalate resin may have an intrinsic viscosity of 0.6 dl / g to 1.8 dl / g. If the intrinsic viscosity of the resin is less than 0.6 dl / g, the mechanical properties thereof deteriorate. There is a problem of deterioration. At this time, the intrinsic viscosity is a value obtained by dissolving polybutylene terephthalate resin in methylene chloride and measuring the resultant filtrate using a Uberode-type viscometer at 20 ° C.

[Thermoplastic Polyether ester  Elastomer (Thermoplastic polyester elastomer, TPEE ) Suzy]

The thermoplastic polyetherester elastomer resin is a random block copolymer prepared by condensation reaction of 1,4-butanediol with dimethyl terephthalate and polytetramethylene oxide glycol.

The thermoplastic polyetherester elastomer resin may have a surface hardness of 39 d to 72 d and a hardness of the thermoplastic polybutylene terephthalate resin of less than 39 d may cause low temperature impact and poor compatibility with polybutylene terephthalate And when the shore is more than 72 d, the content of the oil chain composed of the combination of dimethyl terephthalate and polytetramethylene oxide glycol may be lowered and the water blocking effect may be lowered.

The thermoplastic polyetherester elastomer resin may include 5 to 30 parts by weight based on 100 parts by weight of the polybutylene terephthalate resin. When the amount of the thermoplastic polyetherester elastomer resin is less than 5 parts by weight, impact strength and moisture blocking effect may not be obtained. When the amount of the thermoplastic polyetherester elastomer resin is more than 30 parts by weight, fluidity may be lowered and compatibility with polybutylene terephthalate may be decreased.

[ Impact modifier ]

The impact modifier includes glycidyl methacrylate and is excellent in compatibility with polyester and reacts with the carboxyl group at the terminal of the polyester to improve the hydrolysis resistance and to provide a shock which is required in electronic parts such as various connectors, capacitors, Strength can be given.

The impact modifier may include 3 to 20 parts by weight based on 100 parts by weight of the polybutylene terephthalate resin. If the amount of the impact modifier is less than 3 parts by weight, impact strength may be lowered. If the amount of the impact modifier is more than 20 parts by weight, mechanical properties may decrease and fluidity may be deteriorated.

[Hydrolysis inhibitor]

 The hydrolysis inhibitor may be a carbodiimide compound. The hydrolysis inhibitor may include 1 to 3 parts by weight based on 100 parts by weight of the polybutylene terephthalate resin. If the content of the hydrolysis inhibitor is less than 1 part by weight, If it is more than the weight part, the problem of cost increase may occur.

The carbodiimide compound may be N, N'-di-o-tolylcarbodiimide, N, N'-diphenylcarbodiimide, N, N'- , N, N'-di-2,6-diisopropylphenylcarbodiimide, N, N'-di-2-naphthylcarbodiimide, Di-tert-butylphenylcarbodiimide, N, N'-di-p-nitrophenylcarbodiimide, N, N'-di- N, N'-di-p-toluylcarbodiimide, N, N'-di-p-toluylcarbodiimide, Bis-dicyclohexylcarbodiimide, ethylene-bis-diphenylcarbodiimide, benzene-2-dicyclohexylcarbodiimide, Diisocyanato-1,3,5-tris (1-methylethyl) homopolymer, 2,4-diisocyanato-1,3,5-tris (1-methylethyl) - diisop And copolymers of acrylic diisocyanate and polyisocyanate, and copolymers of ropyl diisocyanate.

The hydrolysis inhibitor containing the carbodiimide compound may be a monomer type or a polymer type among the specific examples of the carbodiimide compound described above. More preferably, the hydrolysis inhibitor is a carbodiimide type monomer having excellent reactivity with a carboxyl group Lt; / RTI > In the monomer type, one molecule of the carbodiimide compound reacts with the polyester terminal group to give hydrolysis property, and the polymer type is a polymer type in which the terminal group of the carbodiimide compound reacts with the terminal group of the polyester Therefore, when the monomer type and the polymer type are added in the same amount, the monomer type excellent in reactivity with the polyester terminal group is preferable.

In addition, the polyester resin composition of the present invention may contain additives in accordance with required characteristics. The additives are stabilizers. Antioxidant. A light stabilizer, a release agent, a compatibilizer, a dye, a pigment, a colorant, a plasticizer, a lubricant, and the like.

The stabilizer is a substance that prevents decomposition of a polymer such as heat, oxidation by light, and an acid scavenger. Examples of the antioxidant include phenol-based, phosphorus-based, thioether-based, and amine-based antioxidants. The light stabilizer is a substance that prevents the chains of the polymer from being broken by oxidation by UV. The release agent may be selected from a metal salt of stearic acid, a metal salt of montanic acid, a montanic ester wax, a polyethylene wax, and a silicone-based release agent. The compatibilizing agent is a substance used for the purpose of improving the kneading and dispersing properties of the two or more kinds of materials. The dye and the pigment are used for the purpose of imparting various colors. The dye is soluble in a solvent, but the pigment is insoluble in a solvent. The colorant comprises at least one dye, at least one pigment, or a mixture thereof. The plasticizer is a material which increases the thermoplasticity of the polymer, thereby giving rise to moldability and flexibility. The lubricant is a material which imparts lubricity to the inside and the outside of the polymer to facilitate the process using an extruder or an injection machine.

Another preferred embodiment of the present invention is to provide a molded article produced from the above-described polyester resin composition.

The polyester resin composition according to the present invention comprises a polybutylene terephthalate resin and a hydrolysis inhibitor compound comprising a carbodiimide compound and an impact modifier compound comprising a thermoplastic polyetherester elastomer resin and glycidyl methacrylate .

The above composition is able to produce a molded article satisfying both high flowability, high water resistance and impact resistance. Specifically, the molded article is put in a autoclave at 121 ° C, 100% RH and 2 atmospheres for 144 hours, After the pressure cooker test 144 hr to be evaluated, it may be that the tensile elongation is 90% or more, the tensile strength retention rate is 90% or more, the fluidity is 30 g / 10 min or more, and the bending strength retention ratio is 90% or more. The molded article according to the present invention may be applied to automotive connectors and electric / electronic parts.

[ Example ]

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited to the following examples.

Example  One

10 parts by weight of TPEE (KP3339, Kolon) having a hardness of 39 d and 100 parts by weight of a PBT resin (intrinsic viscosity of 0.9 dl / g, Bulestar) were mixed with glycidyl methacrylate , 5 parts by weight of an impact modifier (PTW, Dupont), and a hydrolysis inhibitor (ZIKA-AH362, ZIKO) containing a carbodiimide compound were uniformly mixed, The mixture was put into a hopper of a twin-screw extruder and then uniformly dispersed through melt-kneading. The kneaded melt was cooled while passing through a water bath and cut to prepare a polyester resin composition in the form of a chip.

Example  2 to 6 and Comparative Example 1  To 4

A polyester resin composition was prepared in the same manner as in Example 1 except that the hardness and weight parts of TPEE, the weight parts of the impact modifier and the weight parts of the carbodiimide compound were changed according to the composition shown in the following Table 1 .

PBT
(Parts by weight) TPEE Impact modifier
(Parts by weight) Hydrolysis inhibitor
(Parts by weight) Hardness (D) content
(Parts by weight) Example 1 100 39 10 5 One Example 2 100 72 10 5 One Example 3 100 40 10 5 3 Example 4 100 40 5 5 One Example 5 100 72 30 5 One Example 6 100 39 10 20 One Comparative Example 1 100 40 10 5 0.5 Comparative Example 2 100 39 40 5 One Comparative Example 3 100 - - 15 One

The chips prepared in Examples and Comparative Examples were dried in a dehumidifying dryer at 120 ° C. for 4 hours or more, and then a test piece was produced using a uniaxial extruder. The tensile strength, tensile elongation, flexural strength, flexural modulus, impact strength, melt flowability and retention of the physical properties were measured in the following manner, and the pressure cooker test was measured to evaluate the hydrolysis resistance of the polyester resin composition. Table 2 shows the results.

(1) Tensile strength, tensile elongation

Tensile strength and tensile elongation were measured according to ASTM D638.

(2) Flexural strength, valgus modulus

Flexural strength and flexural modulus were measured according to ASTM D790.

(3) Impact strength

The impact strength was measured according to ASTM D 256.

(4) Melt flowability

The flow index was measured by the method of ASTM D1238. (235 DEG C, 2.16 kg)

(5) Pressure Cooker Test

The hydrolysis resistance of the specimen was evaluated under the conditions of 121 占 폚, 100% RH and 2 atm.

(6) Property retention

The physical property value of the pressure cooker test (PCT) of 144 hours was divided by the property value of Pressure Cooker Test 0 hr and multiplied by 100 and expressed as a percentage.

liquidity
(g / 10 min) The tensile strength
Retention rate (%) Initial tensile elongation
(%) After PCT
Tensile elongation (%) Tensile elongation retention (%) Bending strength retention (%) Bending modulus retention rate
(%) Impact strength
(kgfcm / cm) Example 1 37 98 109 115 106 95 95 7.7 Example 2 41 95 75 80 107 94 93 7.1 Example 3 38 97 112 116 104 96 95 7.6 Example 4 34 94 71 73 103 92 94 6.9 Example 5 32 96 117 121 103 91 93 7.5 Example 6 31 98.5 85 91 107 97 96 13.6 Comparative Example 1 37 62 114 1.8 1.58 68 91 7.2 Comparative Example 2 24 95 124 132 107 97 98 11.2 Comparative Example 3 32 96 34 35 103 97 96 12.1

As a result of measurement of physical properties, as shown in Table 2, the thermoplastic polyetherester elastomer, the impact modifier and the carbodiimide-based hydrolysis inhibitor were added to the polybutylene terephthalate resin based on Examples 1 to 6 according to the present invention By including them in the optimum range, it is possible to secure superior water-repellent performance, fluidity and impact resistance.

On the other hand, Comparative Example 1 shows that the content of the carbodiimide hydrolysis inhibitor is low and the retention of the physical properties is low. Particularly, the retention of tensile elongation and tensile elongation after PCT is drastically lowered to deteriorate hydrolysis inhibition.

In Comparative Example 2, when the content of the thermoplastic polyetherester elastomer having a Shore hardness of 40 d exceeds the proper amount, it is confirmed that the fluidity is lowered.

In Comparative Example 3, it was confirmed that the initial tensile elongation and the tensile elongation after PCT were remarkably lowered when the thermoplastic polyether ester elastomer was not used.

Thus, the present invention has been described in detail. It will be apparent to those skilled in the art that these specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereby. Accordingly, it is to be understood that the practical scope of the invention is defined by the appended claims and their equivalents.

Claims (7)

Polybutylene terephthalate resin;
5 to 30 parts by weight of a thermoplastic polyetherester elastomer (TPEE) relative to 100 parts by weight of the polybutylene terephthalate resin; 3 to 20 parts by weight of an impact modifier; 1 to 3 parts by weight of a hydrolysis inhibitor comprising a carbodiimide compound. The polyester resin composition according to claim 1, wherein the polybutylene terephthalate resin has an intrinsic viscosity of 0.6 dl / g to 1.8 dl / g. The polyester resin composition according to claim 1, wherein the thermoplastic polyetherester elastomer has a surface hardness of from 39d to 72d. The polyester resin composition according to claim 1, wherein the impact modifier comprises glycidyl methacrylate. The method according to claim 1, wherein the carbodiimide compound is at least one compound selected from the group consisting of N, N'-di-o-tolylcarbodiimide, N, N'-diphenylcarbodiimide, N, N'-dioctyldecylcarbodiimide, N'-di-2,6-diisopropylphenylcarbodiimide, N, N'-di-2,6-diethylphenylcarbodiimide, N-toluoyl-N'cyclohexylcarbodiimide, N'-di-p-nitrophenylcarbodiimide, N, N'-di-2,6-di-tertiary-butylphenylcarbodiimide, N- Di-p-aminophenylcarbodiimide, N, N'-di-p-hydroxyphenylcarbodiimide, N, N'-dicyclohexylcarbodiimide, N, P-phenylene-bis-di-o-tolylcarbodiimide, p-phenylene-bisdicyclohexylcarbodiimide, hexamethylene-bisdicyclohexylcarbodiimide, ethylene-bisdiphenylcarbodiimide Diisocyanato-1,3,5-tris (1-methylethyl) homopolymer, 2,4-diisocyanato-1,3,5-tris (1-methyl ethyl ) And a copolymer of 2,6-diisopropyl diisocyanate. The polyester resin composition according to claim 1, wherein the polyester resin is a polyester resin. A molded article produced from the polyester resin composition according to any one of claims 1 to 5. The molded article according to claim 6, wherein the molded article has a tensile elongation of 90% or more, a tensile strength retention ratio of 90% or more, a fluidity of 30 g / 10 min or more, and a bending strength retention ratio of 90% or more after a pressure cooker test of 144 hours Shaped article.